Dosage

Aprotinin dosing and timing are critical to achieve its beneficial effects. Notwithstanding a recent multicenter, double-blind, placebo-controlled study of three different dosing regimens in patients undergoing first-time CABG surgery, lower aprotinin dosing regimens have not consistently reduced post-bypass blood loss over non-medicated controls. Studies indicate that platelet adhesive capacity is specifically damaged by the first pass of blood through the extracorporeal circuit and...

Helpful Hints andor Variations in Technique

Larger pulmonary allografts than would be chosen for other procedures are useful here. Proximal suture bites should include right ventricular endocardium but should be kept shallow to avoid the first septal branch of the left anterior descending coronary artery. Knots in the polytetrafluoroethylene suture should be fixed with a clip or separate suture to prevent slippage. Figure 55.6. The proximal anastomosis between allograft and right ventricular outflow tract muscle is performed next....

Rationale for Valve Choice in Atrioventricular and Ventricular Outflow Tract Reconstructions

Choosing an AV valve replacement from the available options is relatively straightforward. For the mitral position, all patients under the age of 65 or who have more than a 12 year expected survival should receive a mechanical prosthesis, unless there is a specific and significant contraindication to anticoagulation.32 While multiple styles have been used and are available, the double tilting disc valve made of pyrolytic carbon currently offers the best combination of low thromboembolic...

Comparison to Other Fontan Techniques

A persistent source of postoperative morbidity and mortality following the Fontan operation has been supraventricular arrhythmias. The reported overall incidence of early and late postoperative atrial tachyarrhythmias following various Fontan techniques has ranged from 5-32 .16-20 Four primary factors are important potential contributors to atrial arrhythmias and sinus node dysfunction 1) exposure of the right atrium to the elevated post-Fontan systemic venous pressure with subsequent atrial...

David R Clarke and Deborah A Bishop

Pulmonary valve allografts have been used successfully to reconstruct or repair the right ventricular outflow tract in a variety of pediatric cardiac conditions. One of the most attractive features of pulmonary allografts is their versatility. Allografts are available in a wide variety of sizes and are relatively easy to implant because the tissue is characteristically pliable. Allografts can be placed in critically ill neonates and infants for whom there are limited surgical options but whose...

Antibiotic Sterilization

Early investigations of sterilization methods for heart valves included ethylene oxide,79 irradiation, and b-propriolactone80 in combination with a variety of storage techniques.81 These methods killed the heart valve leaflet cells, damaged the leaflet material properties, and resulted in poor clinical performance. Kosek et al.81a recognized the damaging effects of the above sterilization methods and suggested that the use of fresh allografts would be clinically superior in patient outcome....

Early Complications

The potential sources of early morbidity from a Rastelli operation are most frequently related to anatomic features which restrict the intraventricular baffle, conduit obstruction, and injury to conduction tissue. In a recent review of out experience1 with 101 patients having the Rastelli procedure from 1973 to 1998, risk factors for hospital mortality were the presence of prior surgery (systemic to pulmonary artery shunt), use of circulatory arrest for the repair, longer cardiopulmonary bypass...

Carpentier Edwards Pericardial Valve

The Carpentier-Edwards pericardial valve was introduced into clinical use in 1981 to overcome the complications and failures associated with previous pericardial valve substitutes.28 Long-term follow-up suggest that durability in the aortic position of the CE pericardial valve may be superior to existing porcine bioprosthesis, with freedom from prosthetic dysfunction being 100 and 83 at 12 and 13 years, respec-tively.29 The initial mitral version of the CE pericardial valve was rapidly...

Brief Historical Overview

The first successful construction of a pulmonary conduit was reported in 1965 by Kirklin and coworkers,15 who fashioned a tube of pericardium in the operating room for a patient with pulmonary valve atresia. Klinner and Zenker16 in the same year reported the use of a Teflon tube to bypass the obstruction in patients with Tetralogy Ross and Somerville17 published their experience the following year. In their patients, who had pulmonary atresia, they utilized an aortic homograft as a valved...

Alternate Approaches

Left ventricular outflow tract obstruction with a hypoplastic aortic annulus and or diffuse subaortic stenosis has been a challenging lesion to manage in neonates and small infants. Standard approaches such as balloon or surgical valvotomy are only palliative and often leave the patient with substantial residual stenosis and or insufficiency.10 Many of these patients will eventually require an annular enlargement procedure or aortoventriculoplasty. The tendency to postpone these procedures...

Summary

Aortic insufficiency after the Ross procedure is an uncommon but serious complication. Current data suggests that aortic insufficiency occurs at a rate of 1 to 3 per patient-year.The development of aortic insufficiency can be minimized by careful patient selection, appropriate attention to the size match of the aortic and pulmonary roots and reinforcement of suture lines to prevent dilatation. As more experience is obtained with this operation the long-term results should continue to improve....

Hints

Helpful hints include very high cannulation of the aorta or the use of femoral artery cannula-tion in adults. In addition, the native aorta should be fully mobilized. Left ventricular venting is always used. Continuous suture lines have been advocated by some, but we find that the interrupted technique provides better visibility and allows placement of a larger aortic root on top of a smaller heart by spreading the dissimilarity over the entire circumference of the root. Similar reasoning has...

Age at Operation

Conduits implanted in younger patients survived better than conduits implanted in older children. This finding contrasts with the data of Clarke,16 Schorn et al.,17 and Bando et al. (1995).18 Five year freedom from reoperation was 43 in Clarke's series and 48 in Schorn's. In our experience, 5 and 10 year survival was 91 and 77 for infants, and 83 and 50 for children older than 3 years at the time of operation (Figure 5.6). Univariate analysis favored aortic versus pulmonary homograft and...

Extracellular Matrix

Increasing the duration of the warm ischemia or of the preimplantation processing results in a progressive loss of proteoglycans however, the morphologic characteristics of the elastic fibers and collagen fibrils are retained (Figure 24.1). Collagen crimp (as demonstrated by polarized light microscopy) and the extent of collagen crosslinking were unaltered by extended periods of warm ischemia (i.e., 72 hours) and allograft processing (DG Crescenzo and SL Hilbert unpublished results ). It has...

Omniscience and Omnicarbon Valve

The Omniscience valve is constructed of a pyrolytic carbon tilting disk seated in a metal housing. This valve became available in 1978 in 19 mm and 31mm sizes. Freedom from structural dysfunction of the Omniscience has been reported as 100 at 9 years.13 Reports of somewhat higher rates of thromboembolic events at five year follow-up led to the development of the Omnicarbon valve.14 The Omnicarbon is an improved version of the Omniscience valve, modified with the purpose of improving...

Experience with Pulmonary Valve Replacement Toronto

Our total experience with pulmonary valve replacement at The Hospital for Sick Children and the Toronto Congenital Cardiac Centre for Adults to the end of 1995 consisted of 661 patients. Of these, 160 (30 ) have undergone 200 reoperations to replace the prosthetic pulmonary devices. In a recent analysis of our experience from 1966 to 1994, my associates and I reviewed the first 606 patients to determine the importance of various factors in predicting long term outcome. A multivariate analysis...

Porcine Bioprosthesis

In the case of the stented porcine bioprosthe-ses, implantation is straightforward and low risk. The majority of surgeons can successfully implant a stented porcine bioprosthesis in less than 60 minutes of cross-clamp time. Operation mortality is commonly less than 5 and often less than 2 . When large size stented porcine bioprostheses are implanted hemodymanics are generally good, but in sizes of 21 millimeters in diameter or less, an outflow tract gradient is common. In terms of durability,...

Erle H Austin III

The primary concern of surgeons and cardiologists with the outcome of the Ross procedure is the development of insufficiency of the pulmonary autograft (neo-aortic valve). Although mild insufficiency is commonly noted following pulmonary autograft technique, the potential for development of severe or progressive neo-aortic insufficiency requiring reoperation has dissuaded many surgeons from including this operation in their surgical repertoire. Present evaluation of reported results of the Ross...

Indications for Rastelli Operation

Left ventricular outflow tract obstruction can be dynamic or fixed and this must be determined preoperatively in order to decide whether an arterial switch procedure with VSD closure is sufficient to correct the anatomic defect or whether alternative procedures are required. If the pulmonary valve annulus is of adequate size, then serious consideration should be given to the arterial switch approach since the outlet septum will shift towards the right ventricle once the left ventricle is...

Richard A Hopkins

Since the first report of the pulmonary autograft procedure by Donald Ross in the Lancet, 1967, there has been a slow but steady increase in its acceptance as a procedure of choice for specific patient subsets.1-8 As the advantages have been gradually delineated, the procedure has been expanded to include not only children, but neonates, and in patients with significant distortion of the left ventricular outflow tract.9-12 The durability of the pulmonary valve appears to be excellent once...

References

Replacement of the aortic and mitral valve with a pulmonary valve autograft. Lancet 1967 2 956-958. 2. Pillsbury RC, Shumway NE. Replacement of the aortic valve with the autologous pulmonic valve. Surg Forum 1966 17 176-177. 3. Barratt-Boyes BG. Homograft aortic valve replacement in aortic incompetence and stenosis. Thorax 1964 19 131-150. 4. Ross DN. Homograft replacement of the aortic valve. Lancet 1962 2 487. 5. Murray G. Homologous aortic valve segment transplants as surgical...

LTransposition of the Great Arteries with Outflow Chamber and Aortic Arch Hypoplasia

The patients with L-transposition of the great arteries with an outflow chamber and hypoplas-tic aortic arch present a technical challenge for reconstruction of the aortic arch.5,6 The aorta is positioned anterior and leftward and the main pulmonary artery is rightward and posterior (Figure 61.6). One option for repair of the aortic arch and association of the proximal main pulmonary artery into the aortic arch is accomplished by augmenting the aortic arch in the same fashion as described above...

Modulation of Valve Antigenicity

A reduction of the antigenicity of the transplant could lead to a less aggressive immune response of the acceptor. Reducing the number of cells expressing transplantation antigens, as mentioned on the preceding pages could be an option, provided the function of the valve leaflets remains unaffected. Preservation methods could therefore be considered as a form of immunomodulation, because this process disturbs the composition of the cells in the valve allograft. It has been reported by el Khatib...

Contents

vii xi Contributors xix 1 The Use of Homograft Valves Historical Perspective 3 Section II Major Clinical Series of Homograft Valve Transplants Left Ventricular Outflow Tract 2 Mayo Clinic Series 17 Robert B. Wallace and Thomas A. Orszulak 3 University of Alabama at Birmingham Series 23 David C. McGiffin and James K. Kirklin 4 Modified Root Replacement Concept Influence of Implant Technique on Allograft Durability 30 Section III Major Clinical Series of Homograft Valve Transplants Right...

Results with Procedure

The largest series of patients who have undergone the pulmonary autograft procedure are reported by Donald Ross and his colleagues in London and by Ronald Elkins et al. in Oklahoma. Total follow-up in the London series is 24 years with an 80 actuarial survival and 85 freedom from replacement at 20 years postoperative.7 The Oklahoma series offers shorter follow-up of ten years but confirms Ross' conclusions thus far.8 There has been little or no residual or recurrent left ventricular outflow...

Conclusions

There is not yet an ideal substitute for the natural pulmonary valve and its artery. In cardiac anomalies requiring construction of a connection between the right heart and the pulmonary arteries, reoperation may be inevitable. Consideration of the long term outlook for the patient should be made at the initial and at each subsequent operation. Recognizing that the absence of a pulmonary valve is well tolerated in otherwise healthy individuals for many years, the surgeon should first consider,...

Denver Patient Population

From May of 1979 through July of 1984, 24 children underwent right ventricular outflow tract reconstruction with the Carpentier-Edwards porcine valved conduit.There were 14 females (58 ) and 10 males (42 ). Patient age and weight at operation ranged from one month to 13 years (mean age 4.2 years) and Type of Right Ventricular Outflow Tract Reconstruction Type of Right Ventricular Outflow Tract Reconstruction Aortic insufficiency with or without aortic stenosis Aortic atresia, hypoplastic...

Patient Population

Between February 1985, and December 1996, 35 children received a cryopreserved aortic valve allograft to repair or replace their right ventricular outflow tract. The patient group was comprised of 22 females (63 ) and 12 males (37 ). Age at operation ranged from nine days Table 6.3. Early Postoperative Morbidity. Type of Right Ventricular Outflow Tract Reconstruction Table 6.3. Early Postoperative Morbidity. Type of Right Ventricular Outflow Tract Reconstruction Sepsis, mediastinitis or...

Explant D

Aortic allograft explant D originated from a female adult (heart beating) donor. It was cry-opreserved with DMSO 10 following antibiotic treatment and implanted in the aortic root of a male adult because of prosthetic valve endocarditis. It was explanted 5 months later, after the patient died in a car accident. No allograft aortic wall tissue was available for study as only the leaflets were explanted. The leaflets were thickened but pliable with a smooth surface. Histology showed a slight...

In Vitro Cell Seeding

The following fundamental and practical questions are being addressed in our laboratory as well as by other investigators concerning the in vitro cell seeding of TE HV scaffolds 1. What quantity of tissue is required initially and how many passages will provide an adequate number of cells for in vitro seeding 2. Is there a safe tissue source and practical method to harvest autologous vascular and valvular tissues and 3. Does the anatomic source of autologous cells affect in vivo...

Kim F Duncan

Distal extension of the allograft is seldom required, usually only in cases with nonconfluent central pulmonary arteries or when a long LV-PA conduit is required. The use of proximal extension in all cases of RVOT reconstruction incorporating a valved allograft conduit has been based on the following principles 1. Placement of the allograft valve cephalad to the native position to reduce sternal compression. 2. Use of a complete cylinder of prosthetic material at the base of the allograft to...

Heart Valve Dissection

Hearts must be received at the processing facility in time to allow for completion of dissection, evaluation and the initiation of antibiotic treatment within the established ischemic time limits. Dissection of the allograft is performed in an aseptic cleanroom environment under laminar flow conditions. The working area should be sterile and draped according to normal surgical protocol. As well as using sterile instruments, ligatures, and grafts sizers, LifeNet utilizes a specifically designed...

Technique

The patient is placed on cardiopulmonary bypass with bicaval cannulation. Hypothermic cardioplegic arrest is induced. The best way to create the ventriculotomy is to place a finger through the mitral valve so as to palpate the location of the papillary muscles (Figure 52.2) and perform the ventriculotomy relatively low on the ventricle, cutting to the surgeon's finger (Figure 52.3). The anterior papillary muscle is usually located just to the right of this ven-triculotomy.3 This technique is...

Surgical Technique

The pulmonary valve and annulus are evaluated and intracardiac repairs accessed through a vertical right ventriculotomy (Figure 55.8). When annular dimensions are deemed inadequate, the incision is extended across the pulmonary annulus and into the main pulmonary artery. The pulmonary artery trunk and distal right and left branches are evaluated and dissected out as necessary. CV-5 polytetrafluo- Figure 55.8. A vertical right ventriculotomy provides access for repair of more complex cardiac...

Right Ventricular Outflow Reconstructions with Cryopreserved Allografts

As has been clearly demonstrated in a number of centers, human tissue is superior material for reconstructions of the right ventricular outflow tract.29-33 Fontan and associates29 have reported 103 homograft reconstructions between 1968 and 1983 with no episodes of valvular dysfunction, thromboembolism, or hemolysis, although one-third of the patients died either early or late. None of these deaths was due to the aortic valve allograft itself, and only one replacement was required for the...

Recipient Sensitization

The endothelium is perhaps the most immuno-logically potent component of allografted tissues.14 Endothelial cells in a mixed lymphocyte cell culture reaction have been shown to be two to three fold more stimulatory than peripheral blood lymphocytes.2 Recipient sen-sitization, therefore, might be expected to be predictable based on antigenic properties of the endothelium, mass of endothelium present, and viability of donor cells. One of the earliest studies of allograft immunogenicity in the rat...

Viability

The demonstration of endothelial cells presence on allograft valves must not be considered equivalent to proof of cell viability. Viability is a property that has been imputed to allograft valve tissues, often with little evidence to support it. Viability has many dimensions, including the ability of the cell to replicate, synthesize essential proteins, and effect changes on other cells. These properties may be symmetrically or asymmetrically affected by storage protocols, implant techniques...

Richard A Hopkins Diane Hoffman Kim Robert H Messier Jr and Patrick W Domkowski

Extensive clinical durability of allograft valves has long been suggested to be linked to cellular viability and extracellular matrix integrity at the time of implantation.1-3 Efforts to standardize processing procedures for valve transplantation and optimize the longevity of the valves provided the original impetus for researchers to examine the effects of each processing step. This chapter focuses on the series of studies that resulted from this work. As reviewed in the previous section,...

Results with a Cylindrical Dacron Proximal Extension

Between July 1988 and June 1996, 43 patients underwent reconstruction of the right ventricular outflow tract incorporating an allograft valve conduit with a sealed knitted Dacron extension. Ages ranged from five days to 14 years with a mean of 2.1 years. Diagnostic categories included tetralogy of Fallot with hypoplastic pulmonary arteries, pulmonary atresia with ventricular septal defect, pulmonary atresia with ventricular septum, absent pulmonary valve syndrome,transposition of the great...

Skirt Technique

With the skirt technique an oval piece of pericardium (treated or autologous) that is generously sized is sutured with a continuous suture to a longitudinal pulmonary arteriotomy (Figure 53.12). This method is utilized in Figure 53.10. Distal anastomosis is accomplished with two polypropylene (5-0 or 6-0) sutures, each begun as mattress sutures at the two triangulation junctures of the pericardium (with the allograft and the native pulmonary artery). Figure 53.10. Distal anastomosis is...

Surgical Exposure and Collateral Mobilization

In patients undergoing single stage unifocaliza-tion, our standard approach is through a midline sternotomy. Initially, we attempt to expose and control all collaterals and true pulmonary arteries before resorting to cardiopul-monary bypass, and then ligate the collaterals at the institution of bypass. This is essential to prevent collateral steal, which may be a significant cause of neurologic morbidity in these patients. In order to control and adequately mobilize all collaterals through the...

Stephen L Hilbert Frederick J Schoen and Victor J Ferrans

Despite the wide clinical use of allograft heart valves, studies of the pathological features of explanted cryopreserved allografts have been reported only recently. Further analysis of explanted allograft valves is needed to clarify the following important issues 1) whether and to what extent viable cells are retained in optimally cryopreserved allografts 2) what mechanisms of cell death (e.g., necrosis, apoptosis) underlie their attrition 3) whether and to what extent allograft cells are...

Techniques

The inclusion-root technique, or intra-aortic cylinder technique, is used primarily in the patient whose annulus is 30 mm or larger. By using the allograft valve with its intact aortic sinuses as a small cylindrical tube, competence is assured. For this technique, the selected allo-graft should have an internal diameter 1-2mm less than that of the host aortic annulus. The allograft aorta is transected 2 to 4 mm above the sino-tubular ridge the allograft is trimmed, leaving a 2- to 3-mm cuff...

Richard A Hopkins and Erle H Austin III

The spectrum of pulmonary atresia with ventricular septal defect, nonconfluent or absent central pulmonary arteries with multiple major aortopulmonary collateral arteries (MAPCAs) presents a significant surgical challenge. Complete repair requires unifocalization of all available segmental and lobar pulmonary blood supply so that a central pulmonary ventricle to pulmonary arterial reconstruction can be created. When central pulmonary arteries are not merely nonconfluent but actually absent,...

Stephen L Hilbert Frederick J Schen and Victor J Ferrans

As described above, our collective preclinical and clinical experience has served to identify clearly the pathologic changes that occur following the implantation of fresh and allograft heart valves in the systemic circulation in juvenile sheep and in human patients. The morphologic findings in this series of investigations demonstrate that a marked reduction in mitotic activity occurs in both the endothelial cells and connective tissue cells of the allografts within a few days of implantation....

Technique of DNA In Situ Hybridization for the Y Chromosome

In situ hybridization, which has its roots in the field of pathology, allows the detection of specific nucleic acid sequences in histological sec-tions.17 All chromosomes contain nucleic acid sequences in histological sections.17 All chromosomes contain nucleic acid sequences that are specific for that chromosome. Detection by ISH of such Y-chromosome specific sequences in a cell nucleus demonstrates the male origin of that specific cell. The principles of ISH are schematically outlined in...

Technique with Aortic Allograft

Allograft Ring Technique

The patient is placed on cardiopulmonary bypass usually with dual caval cannulas, but a single right atrial cannula can also be used if the only operation to be performed is pulmonary valve replacement. In the absence of septal defects, cardioplegia is contemplated on the branch pulmonary arteries. The right ventricular outflow tract is approached initially with an incision in the proximal pulmonary artery, which is extended across the region of the annulus. The incision is extended into the...

Harvesting and Transportation of the Donor Heart

The valve leaflets consist of a cellular component and an acellular component. The major acellular components are collagen types I and III, elastin and glycosaminoglycans. A network of tropocollagen molecules covalently cross-linked form the fibrous protein matrix of valve leaflet tissue. Heart valves also contain acid glycosaminoglycans (GAGs), which consist of polysaccharide (about 95 ) and protein (about 5 ). The main GAGs in heart valves are hyaluronic acid, dermatan sulfate and chondroitin...

Cell Origin in Porcine Cryopreserved Allograft Explants

Before examining human allograft explants, we studied the feasibility of establishing an ISH protocol to determine cell origin in allograft explants in a experimental setting, using a porcine model.16 Previous experience convinced us of the usefulness of the growing young pig model for valve research purposes.19 In a small series, three aortic grafts one from a male pig donor, two from female pigs were cryopreserved according to the standards for human allografts, and then implanted in the...

Early and Late Results

Experience with this procedure is much more limited when compared to the Rastelli operation. However, sources of morbidity and mortality may be similar to those of the Rastelli operation. Preliminary results indicate Figure 46.7. The aortic autograft is re-inserted into the LV outflow. The coronaries are then reimplanted anteriorly. Prior to re-establishing ascending aortic continuity, the branch pulmonary arteries Figure 46.7. The aortic autograft is re-inserted into the LV outflow. The...

Aortic Pulmonary Valvar Relationship

In performing the Ross procedure, plane must be developed first between the aortic and pulmonary valves, and then posterior to the pulmonary infundibulum. This extends 4 to 5 mm below the edge of the left facing and lateral pulmonary valvar leaflets during the harvesting of the autograft. The first area contains dense connective tissue, which must be sharply divided, but then one encounters a well developed plane of cleavage in the region of the free-standing pulmonary root. This plane is...

Low Temperature Compatible pH Buffers

Biocompatible pH buffered solutions should consist of at least a basic salt solution, an energy source (i.e., glucose) and a buffer capable of maintaining a neutral pH at refrigerated temperatures. In the blood of mammals the pH rises in parallel with the neutral point of water during cooling in the range of 0 C to 40 C.68 The rate of change of pH with temperature is -0.017 pH units C. This phenomenon is referred to as alpha-stat regulation in recognition of the fact that both the intracellular...

Technique with Pulmonary Allograft

Pulmonary allografts can be used as conduits or orthotopic valve replacements.8 The technique is similar to aortic allograft in the pulmonary position except that the role of the anterior leaflet of the mitral valve is replaced with a trapezoidal patch of pericardium. This patch is kept generous so as to not deform the annulus of the pulmonary valve with tightening during ventricular contractions (Figure 51.5). The distal anastomosis is usually not as oblique as with an aortic allograft, as the...

Rastellis Operation Applications and Techniques

The surgical management of complex forms of transposition of the great arteries with ventricular septal defect continues to present a challenge to the cardiac surgeon due to the wide variability in anatomy and the disappointing late results with current approaches. For this reason, several techniques have been proposed. However, Rastelli's operation remains the most widely applied procedure for surgical repair of transposition of the great arteries, ventricular septal defect and left...

Use of the Pulmonary Allografts Background

Intuitively, it seemed that a pulmonary allograft would be the ideal option for reconstitution of right ventricle to pulmonary artery continuity because it represented the most complete restoration of native structure and function. In addition, it was postulated that pulmonary allografts should not calcify as quickly as aortic allografts that have an intrinsically greater elastin and calcium content in their conduit walls (1904).As demand for aortic allografts for left ventricular outflow tract...

Distal Stenoses

When stenoses occur beyond 1-2 cm from the mid-point of the pulmonary artery confluence, deviation of the distal anastomosis to cover the stenoses becomes difficult. After splitting through the length of the stenosis (Figure 53.6), the pulmonary artery is enlarged with a patch of pericardium constructed so as to develop both height and width to the stenosed pulmonary artery (Figure 53.7). Pericardium is usually sutured with 5-0 or 6-0 monofilament suture to the pulmonary artery. The sutures are...

Modified Scallop Technique Minimal Scallop of Non Coronary Sinus

The modified scallop technique is similar to the later method of Ross,6 as it leaves the non-coronary sinus relatively intact to buttress, or fill, the base of the aortotomy incision and allows deferral of the decision on what to do with the aortic root geometry until after the proximal suture line has been completed (Figure 32.16). To use this technique, the native aortic root must not need annulus enlargement or an augmentation aortoplasty at the level of the sinus ridge. The non-coronary...

Tissue Processing Decellularization Sterilization and Storage

The currently available decellularization methods effectively remove cuspal endothelial cells and interstitial cells however, incomplete removal of conduit wall smooth muscle cells and subvalvular cardiac myocytes remain problematic. An inflammatory cell infiltrate is typi cally observed surrounding remnants of cardiac myocytes. In addition to triggering an inflammatory response, muscle cell remnants (e.g., disrupted plasma membranes) serve as nucle-ation sites for calcification. Further...

Variations in Technique

The preceding techniques are clearly derived from those described by the pioneers of allo-graft valve transplantation. Variations have been suggested by many authorities. Placement of the initial three sutures can be underneath the commissural post rather than at the base of each sinus. A 120 counterclockwise rotation can be used as originally described by Barratt-Boyes.5 We have found it easier to align the native coronary ostia to the analogous portions of the allograft coronary sinuses and...

Expression of Inflammatory Mediators

Endothelial cells express numerous mediators of the inflammatory response. One important class of mediators are the leukocyte adhesion molecules (LAMs). LAMs are involved in a wide variety of inflammatory conditions, including sepsis, autoimmune disorders, and response to allogenic tissues. Leukocytes have specific ligands for different LAMs, which are expressed by endothelial cells in response to cytokines such as interleukin-1 and tumor necrosis factor a. Thus, expression of LAMs leads to...

Indications and Contraindications

One of the major reasons for failure of freehand aortic valve implants is lack of attention to aortic root geometry and its effect on the functional anatomy of the allograft. BarrattBoyes and associates clearly demonstrated the problem of native aortic root dilatation causing failure.1 Aortoplastic techniques can be applied to both dilated and constricted aortic roots, and they are also applicable to the normal aortic root for which closure of the aortotomy would result in narrowing at the...

Pulmonary Artery Reconstruction during the Fontan Operation

Often times patients who are candidates for a Fontan operation for terminal palliation have some pulmonary distortion or need augmentation of their central pulmonary arteries. This is most frequently seen in patients following a Norwood operation where the central pulmonary artery confluence may sometimes be narrowed. Whether the patient is to undergo a total cavopulmonary connection or a hemi- Fontan, the superior cavopulmonary connection can be accomplished in the same fashion. following...

Explant A

Explant A is an aortic allograft from a female adult (heart beating) donor. Cryopreservation was with DMSO 10 after antibiotic sterilization. The allograft was used for subcoronary aortic valve replacement in an adult male recipient with aortic valve stenosis. Six months later the allograft was explanted because of para-valvular leakage. Macroscopy showed slightly thickened leaflets and an elastic aortic wall without calcifications. Routine HE histologic examination showed a variable but still...

Efficacy

Numerous studies have conclusively demonstrated less blood loss in aprotinin treated cardiac surgical patients in the post-bypass period when compared to non-medicated controls. The mean difference in blood loss between aprotinin treated and control patients undergoing a primary elective CABG procedure is in the region of 200-400 ml. At those institutions utilizing conservative transfusion triggers (i.e. Hgb < 9.0g dl) use of homologous blood products usually is not significantly different...

Il

Incision through the stenotic pulmonary artery confluence and sizing of the oval piece of pericardium for the skirt technique. situations where there is no main pulmonary artery, the confluence is hypoplastic, but the left and right main pulmonary arteries enlarge as they approach the hila. The pulmonary arteri-otomy is extended to the more-normal-diameter arteries in the hila. The skirt of pericardium is sutured with a continuous suture to the edges of the arteriotomy (Figure...

Assessment of Pulmonary and Aortic Annuli Geometric Mismatch

It is now well delineated that geometric mismatch between the diseased aortic valve and the normal pulmonary valve is a common cause of significant aortic insufficiency and ultimately surgical failure after the Ross procedure. TEE is an excellent tool to assess both the aortic and pulmonary valve diameters and determine surgical feasibility of the Ross procedure prior to dissection and harvesting of the pulmonary autograft. The aortic valve can be visualized in a variety of TEE imaging planes....

Management of Complicating Coronary Anatomy

In the idealized aortic valve, the sinuses are of equal size, and the right and left coronary ostia are at 120 angles.9 Techniques have been described as though one perfectly symmetric valve is always inserted into another symmetric annulus. However, just as the ancient concept of the idealized human fitting into a perfect circle was wrong, rarely is the human aortic valve so symmetric. The pathology of aortic insufficiency and stenosis further alters the native symmetry. These alterations in...

Inferences from Natural History and Surgical Experience

Survival without a pulmonary valve is possible. Shimazaki and coworkers2 gathered data from the literature on 72 patients with isolated PI. These individuals were symptom-free, with survival not different from the normal population for the first 20 to 30 years of life. After age 30, however, a rapid increase in the onset of symptoms was documented. Three of the 72 patients died, at an average of 39 months after developing symptoms. It is probable that individuals with PI and congenital heart...

Monitoring of Anticoagulation

When celite is used as the contact-activating agent (Hemochron, International Technodyne Co.), there will be a prolongation of the ACT that is independent of heparin concentration. At concentrations of aprotinin achieved clinically with the high-dose regimen, activated factors in the intrinsic coagulation cascade (XlIa, XIa, XIa, Villa) are partially inhibited. Dietrich et al.15 demonstrated that aprotinin acts as an anticoagulant by inhibiting pro-thrombin activation during CPB. Some of the...

Doff B McElhinney V Mohan Reddy and Frank L Hanley

Pulmonary atresia with ventricular septal defect is a spectrum of lesions distinguished by a marked heterogeneity of pulmonary blood supply.1-3 Perhaps the most challenging subset of patients with this anomaly are those in whom pulmonary blood flow is derived entirely or in large part from aortopulmonary collateral arteries (MAPCAs). These collaterals, which are thought to arise from the embryonic splanchnic plexus, can originate from the aorta, the subclavian or carotid arteries, the...

Recommendations

Whenever possible, reconstruction of the connection from the heart to the pulmonary arteries should be made with the patient's own tissue. incompetence accelerates. Three deaths occurred an average of 39 months after developing symptoms. It is probable that patients with pulmonary valve incompetence and associated congenital heart disease, such as Tetralogy of Fallot, will develop symptoms at a earlier age than those with pulmonary insufficiency and a normal heart. The addition of a monocusp to...

Resistance to Thrombus Formation

The normal endothelium is a powerful inhibitor of thrombus formation. Some of the properties of the endothelium that contribute to its thromboresistance include a strongly negative electrical charge, production of prostacyclin, binding of thrombin by synthesis of antithrom-bin III, elaboration of tissue plasminogen activator, and production of plasminogen-activator-inhibitors.10 This listing of potentially important antithrombotic properties does not suffice as a complete explanation for why...

Peripheral Neo Pulmonary Artery Reconstruction

Although native tissue to tissue anastomosis is almost always achievable between collaterals and other collaterals or between collaterals and true pulmonary arteries, it is sometimes beneficial to augment the peripheral neo-pulmonary arteries, either to enlarge discreetly hypoplastic or stenotic arterial segments, or to optimize the cross-sectional area of anastomosed collaterals. For this purpose, we prefer to use pulmonary artery allograft, which is more pliable and appropriate to the...

Perry L Lange and Richard A Hopkins

The use of human allograft heart valves for replacement of congenitally defective or diseased heart valves has become normal practice in cardiothoracic surgery. From the early days of using wet-stored nonviable homografts to current methods of transplanting cryopre-served viable allografts, the superiority of human heart valve implants has been well doc-umented.1-7 Clinical demand for allograft heart valves is still growing. However, supply of this valuable human resource has become a limiting...

Target Antigens

The effect of compatibility for the ABO blood group antigens between valve donor and accep tor on graft-survival has sparsely been reported in the literature. In the only available study, Balch et al. showed that there was no relationship between ABO compatibility and long term valve allograft survival.18 In this study, the majority of the patients with valve failure (130 188) were ABO compatible. Regardless of this finding, the authors mentioned the presence of denuded endothelium, fibrin...

Bjork Shiley Valve

The Bjork-Shiley valve is a single tilting disk mechanical prosthesis first implanted in the aortic position in 1969.7 Since then, it is estimated that nearly 24,000 of these valves were implanted in patients worldwide, with as many as 7,000 presently living with the valve in place.8 This valve was removed from the market in 1986 because of reports of strut fracture in certain models. A review of the valve's performance in 785 patients over a 15 year period revealed no structural deterioration,...

Use of Transannular Patch Background

Because in the pediatric population, synthetic porcine valved conduits suffered from unac-ceptably high early failure rates and aortic valve allografts although fairing better, seemed never-the-less doomed to degeneration and eventual failure, many surgeons returned to Table 6.4. Allograft Replacement in Aortic Allograft Recipients. Table 6.4. Allograft Replacement in Aortic Allograft Recipients. Aortic atresia, hypoplastic aortic arch (s p Damus-Kaye-Stansel) Allograft insufficiency, distal PA...

Results

Nine of the porcine valved conduit recipients (38 ) died within 30 days of operation and are detailed in Table 6.2. As depicted in Table 6.3, 87 of all patients who received a porcine valved conduit experienced significant postoperative complications. Fifteen operative survivors have been followed for three months to 12.2 years (mean follow up 6.4 years). Two children were clinically well when they were lost to follow up at 6.8 and 6.9 years after implantation of their xenograft. Three of 13...

Central Pulmonary Artery Reconstruction

In patients with pulmonary atresia and MAPCAs, except those with generous true pulmonary arteries and minor collateral contribution to pulmonary blood flow, it is almost always necessary to augment the central pulmonary arteries. In some cases, the anatomy of collaterals and true pulmonary arteries is conducive to reconstruction of the central pulmonary arteries without the need for nonautologous tissue. But in many cases, it is necessary to reconstruct the central pulmonary arteries using...

Appendix Valve Diameters

Table A1 lists mean normal valve diameters the first column for each valve comes from the data measured by Rowlatt and associates. The Great Ormond Street (GOS) group have found that these valve measurements tend to underestimate the true in vivo sizes. The data from Rowlatt and coworkers (RRL data) were derived from a large series of normal hearts examined at autopsy. The Great Ormond Street group noted that there was a shrinkage factor due to formalin. Their angiographic estimates were...

Tubular Hypoplasia of the Transverse Aortic Arch with or without Coarctation

Hypoplastic Transverse Aortic Arch

When coarctation is associated with a diffusely hypoplastic transverse aortic arch, coarctation repair alone may not relieve the aortic obstruction because of residual obstruction across the hypoplastic transverse arch. These patients may have an associated ventricular septal Figure 61.12. The upper one-half of the anastomosis, both anteriorly and posteriorly, is made with a running suture. Figure 61.12. The upper one-half of the anastomosis, both anteriorly and posteriorly, is made with a...

Damus KayeStanzel Anastomosis with or without Aortic Arch Augmentation

Damus Kaye Patch Revision

Those patients with subaortic obstruction and who are destined to a single ventricle repair (Fontan) and who have a normal pulmonary valve, can frequently undergo a Damus Kaye Stanzel anastomosis.7'8 This involves association of the divided proximal main pulmonary artery with the aortic arch so that the unobstructed outflow tract to the pulmonary valve an be utilized for systemic outflow to the aorta (Figure 61.20). Depending upon the anatomy and relationship of the great vessels and whether...

Anatomy and Classification

In 1949, Collett and Edwards1 proposed a classification system based on the arrangement of the origins of the pulmonary arteries from the truncal artery (Figure 56.1). The classification proposed by Van Praagh and Van Praagh2 also includes cases with a single pulmonary artery and various degrees of development of the ascending aorta and ductus arteriosus. In the Collett and Edwards Type I truncus, the pulmonary arteries arise from a common pulmonary trunk that originates from the truncus. In...

Techniques to Minimize Aortic Insufficiency

Modification Manouguian Techniques

Taking these findings into account, several technical aspects may be important in minimizing the development of aortic insufficiency after the Ross procedure. The experience of Ross would suggest that implanting the pulmonary valve inside the aortic root might have significant merit. Certainly, the potential for dilatation of the aortic root would be minimized if the pulmonary valve is sewn freehand in a sub-coronary position or placed inside the aortic root as a cylinder (inclusion technique)....

ECM Scaffolds

The development of an ECM scaffold has been occurring in parallel with the research activities focusing of biodegradable polymers. As discussed above, the limitations imposed by synthetic biodegradable materials such as the polymer degradation rate and biomaterials properties, may be circumvented by the selection of a tissue-derived biomaterial capable of accommodating the biomechanical requirements of a HV. Decellularized (also referred to as acellular or devitalized) aortic and pulmonary...

Proximal Suture Line

Desenhos Tmber Quatro Menina Tubler

After preparation of the allograft and resection of the native valve, three sutures of 4-0 monofilament polypropylene on a taper-point half-circle needle are placed as simple sutures, relating the middle of each recipient sinus to the donor coronary ostia (Figure 32.3). They are placed as simple sutures beginning with the base of the left sinus of the allograft lined up to a position directly underneath the left coronary of the recipient (Figure 32.4). Similarly, a simple suture is placed...

Safety and Toxicity

One of the principal safety concerns associated with the use of aprotinin is the potential for thrombotic complications including early saphenous vein closure and perioperative MI and stroke. Cosgrove et al.4 reported a trend toward an increased incidence of MI in apro-tinin treated redo-CABG patients. Although not statistically significant, the incidence of Q-wave infarction was 17.5 in a high-dose aprotinin group versus 8.9 in a control group. In addition, autopsies of seven patients who died...

Mayo Clinic Series

Homograft Aortic Valve Replacement

Orszulak The use of cadaveric aortic valve homografts for the replacement of diseased aortic valves began at the Mayo Clinic in 1965. The impetus for initiating this program was concern regarding the available prosthetic valves, especially the hemodynamic characteristics and the incidence of thromboembolism, and the favorable early results achieved by Donald Ross1 and Brian Barrett-Boyes2 in the use of aortic valve homograft in the subcoronary position beginning...

Pulmonary Artery Bifurcation Allograft

When the pulmonary arteries are nonconfluent, choices exist for reconstruction. First, the pulmonary artery bifurcation can be reconstructed entirely with a pulmonary bifurcation allograft with separate end-to-end anastomoses right and left, as reported by McGrath and colleagues (Figure 53.22), or sewn to an aortic allo-graft in a manner analogous to the technique just described when the distance is great (Figure 53.23). Second, the absent posterior wall of native pulmonary arterial confluence...

The role of Homograft Valves in the Treatment of Endocarditis

Homograft Aortic Valve

The value of surgical intervention in patients with NVE who develop heart failure, uncontrolled infection and aortic root abscess formation has been previously demonstrated.18 Similarly, surgical therapy for some patients with PVE18,19 has improved the high mortality associated with this condition. Patients with PVE and heart failure, uncontrolled sepsis, prosthesis dehiscence, prosthesis obstruction and fungal etiology are the ones most likely to benefit from valve replacement. One of the...

University of Alabama at Birmingham Series

Homograft Aortic Valve Replacement

Kirklin Homograft valves have proved a useful replacement device in the management of aortic valve and aortic root pathology. Since the first insertion by Ross,1 in 1962, a number of different methods of homograft valve collection, sterilization, storage and insertion have been used. Consequently, this has made comparison of results between the centers that have achieved considerable experience with this valve difficult. The purpose of this section is to present...

Bicuspid Aortic Valve with 180 Coronary Ostia

Aortic Valve Coronary Ostium

In a situation where the coronary ostia are at 180 angles from each other in the native aortic root, simple orthotopic placement of a trileaflet valve would be defeated. Once again, if the allograft aortic valve is clearly the optimal choice for the patient, it can be managed with enlargement of the non-coronary sinus region of the native aortic root with or without an annuloplasty. Most often, an annuloplasty is also required that rotates the native coronary Figure 34.12. Large native left...

Asymmetric Placement of Coronary Ostia Within Native Sinuses Mini Rotation

Right Coronary Ostium

A common geometry involves rotational displacement of the right coronary orifice to the right within its sinus such that the right and left coronary ostia begin to approach 180 Figure 34.10 . Occasionally, asymmetry of the allograft sinuses allows management by rotating sinuses e.g. allograft left to recipient right . Usually placement of an allograft inside this geometry requires a slight rotation, placing the left coronary ostia closer to the pillar between the left and non-coronary sinuses...

Aortic and Pulmonary Valves General Morphologic Features

Heart Valve Aortic Histology

Aortic and pulmonary valves are referred to collectively as semilunar valves. The normal aortic valve is non-obstructive when open, competent when closed, non-thrombogenic, non-injurious to blood cells, durable, resistant to infection and, capable of continuously remodeling its extracellular matrix and repairing itself when injured. The dilated pockets of aortic root behind the valve cusps bulge with each systolic ejection of blood and are called sinuses of Valsalva.1 Normally, the three aortic...

Nicks Technique

Annular Enlargement Nicks

The method of Nicks and coworkers can be adapted for use with allografts.4 It is an incision similar to that originally described by Barratt- Boyes.5 The incision across the annulus is made to the right of the commissure between the left and noncoronary sinuses of the native aortic root and extended into the anterior leaflet of the mitral valve Figure 33.6 . It is posterior to the bundle of His. If only a small amount of Figure 33.6. Enlargement of the annulus by extension of the aortotomy...

Preclinical Studies

Apoptotic Bodies

Preclinical animal studies involving allograft heart valves have been conducted predominantly in non-orthotopic models in which an allograft valved-conduit also referred to as an aortic root has been implanted in the systemic circulation thus avoiding the need for car-diopulmonary bypass.1'2 Reconstruction of the right ventricular outflow tract has been accomplished in lambs using cryopreserved and antibiotic-disinfected aortic valve allografts.3 To the best of our knowledge, orthotopic aortic...

Pericardial Bioprosthesis

Pericardial Bioprosthesis

In the case of the pericardial prosthesis, implantation is also straightforward and low risk with cross-clamp times similar to those observed for the porcine bioprosthesis. The operative mortality is also similarly low. In small sizes, a mild gradient may exist across this valve although it might be slightly less than a porcine valve. In terms of durability, the first generation of stented pericardial valves Ionescu-Shiley began to fail at three to four years. However, currently available...

Coronary Arterial Anatomy in Normal Hearts

Coronary Anatomy

Critical for safe excision of the autograft is a knowledge of the anatomy of the left coronary artery. The main stem of the left coronary has been reported to vary in length from 2-20 mm.5 In the hearts examined, its length was from 1 to 8 mm. The first branch of the left anterior descending may be a infundibular branch, completing the ring of Vieussens, but the descending artery gives off from 3 to 6 perforating arteries.6 There is some discussion over whether all are similar in size, or...

Cryopreservation

Immediately following the antibiotic incubation period, packaging and subsequent cryop-reservation of the grafts is begun. All packaging should be performed under strict aseptic conditions within a certified and qualified Class 100 or cleaner laminar flow environment. The allograft is removed from the antibiotic medium, rinsed in fresh antibiotic-free medium, and packaged with enough cryoprotectant solution to produce a total volume of 100 ml. At the time of packaging, cultures of all...

Homograft Valve Insertion for Endocarditis

Valve Homograft

The general principles of the surgical management of endocarditis include a timely valve surgery in the setting of appropriate bactericidal antibiotics, b debridement of all infected tissue including abscess cavities and the infected fibrous skeleton of the heart, c removal of all prosthetic material in PVE, d reconstruction including valve replacement, annular reconstruction and closure of any holes between chambers. Abscess cavities are not specifically closed unless required for the...