Left ventricular mass reduction after aortic valve replacement: homografts, stentless and stented valves.

BACKGROUND: We studied the effect of four different types of prosthetic aortic valves on time course and extent of regression of left ventricular hypertrophy after aortic valve replacement for aortic stenosis. METHODS: Four groups of 10 patients each were randomly assigned to receive: (1) aortic homograft preserved in antibiotic solution at 4 degrees C, (2) Toronto stentless porcine valve, (3) Medtronic Freestyle stentless valve, or (4) Medtronic Intact aortic valve. The left ventricular mass index, effective orifice area index, and peak and mean transaortic gradients were measured by Doppler echocardiography before the operation and 8 months postoperatively. RESULTS: The hemodynamic performance indices were much better for the homograft and stentless valves than for the stented one. The absolute left ventricular mass index reduction was greater in the homograft group compared with the Intact (p = 0.0004) and Toronto (p = 0.007) groups. The extent of percent left ventricular mass index reduction was greater only in the homograft group versus Intact group (p = 0.005). The multilinear regression analysis showed that the only predictors of a larger percentage of left ventricular mass index reduction were the homograft type, a higher valve size index, and a higher preoperative left ventricular mass index. CONCLUSIONS: When a stentless or homograft aortic valve was used instead of a stented valve to replace a stenotic aortic valve there was more complete or at least faster regression of left ventricular hypertrophy. The hemodynamic performance of stentless porcine valves was similar to that of aortic homografts, nevertheless the aortic homografts preserved in antibiotic solution offered a faster regression of left ventricular hypertrophy during the same period of time.     

Surgical treatment of prosthetic endocarditis. Aortic root replacement using a homograft

This article reports the successful surgical treatment of six patients who presented with prosthetic endocarditis and uncontrolled bacteremia. They were treated by replacement of the aortic root with a preserved homograft aortic valve. With this technique, ventricular-aortic continuity was established with a centrally flowing valve together with its attached aorta. The weakened aortic and the associated root abscess were thereby excluded from the high-anulus pressure systemic circulation. There were no operative deaths, and the longest postoperative survival time is 10 years. Two patients have conduction disturbance and symptoms relating to their malfunctioning aortic valves. The remaining four patients are all well at 5 years, 2 years, 9 months, and 6 months with no further evidence of infection. Homograft aortic root replacement is a suitable treatment for this potentially lethal condition.     

Intravascular hemolysis in patients with new-generation prosthetic heart valves: a prospective study

OBJECTIVE: A prospective clinical study was designed to assess the frequency and severity of intravascular hemolysis in patients with new-generation, normally functioning prosthetic heart valves. METHODS: Hemolysis was evaluated in 172 patients with a mechanical prosthesis (53 CarboMedics and 119 Sorin Bicarbon) and in 106 patients with a bioprosthesis (15 St Jude Medical Toronto, 19 Baxter Perimount, and 72 Medtronic Mosaic) in the aortic position, mitral position, or both. Aortic valve replacement was performed in 206 patients, mitral valve replacement in 59 patients, and double valve replacement in 13 patients. The presence of hemolysis was assessed on the basis of the level of serum lactic dehydrogenase and serum haptoglobin and the presence and amount of reticulocytes and schistocytes in the peripheral blood. Severity of intravascular hemolysis was estimated on the basis of serum lactic dehydrogenase. Clinical, echocardiographic, and hematologic evaluations were performed 1, 6, and 12 months after discharge. RESULTS: None of the 278 patients experienced decompensated anemia, whereas at 12 months, mild subclinical hemolysis was identified in 49 patients, 44 (26%) with a mechanical prosthesis and 5 (5%) with a bioprosthesis (P <.001). At multivariate analysis, independent predictors of the presence of subclinical hemolysis were mitral valve replacement (P <.001), use of a mechanical prosthesis (P =.002), and double valve replacement (P =.02). Frequency of hemolysis in patients with stented aortic bioprostheses was 3%, whereas it was absent in those with stentless valves. Among mechanical valve recipients, double versus single valve replacement (P =.04) and mitral versus aortic valve replacement (P =.05) were correlated with the presence of hemolysis; double valve recipients also showed a more severe degree of hemolysis (P =.03). In patients with a Sorin Bicarbon prosthesis, hemolysis was less frequent (22% vs 34%, P =.09) and severe (P <.001) than in those with a CarboMedics prosthesis. CONCLUSIONS: In normally functioning prosthetic heart valves, subclinical hemolysis is a frequent finding. A low incidence of hemolysis is found in stented biologic prostheses, and it is absent in stentless aortic valves. Modifications of valve design may contribute to minimize the occurrence of hemolysis in mechanical prostheses.     

Mitral Valve Replacement with Dura Mater Bioprostheses

Dura mater bioprostheses for cardiac valve replacement were first introduced in Brazil. They have been used since 1975 at the National Heart Hospital, London, as a mitral valve replacement instead of fascia lata valves or inverted aortic homograft valves. During this period 120 patients have had dura mater valves inserted in the mitral position; 29 also received an aortic valve replacement, 6 with dura mater, 20 with an aortic homograft, 2 with an aortic xeno-graft and 1 with a prosthetic valve. Perivalvular leaks occurred with seven of these mitral valves, and another seven presented with detached cusps. All but one of these 14 valves were replaced. Emboli have occurred in four of the patients, one of whom died after 35 months with thrombus on the aortic valve, but with an unaffected mitral valve. There were 15 early deaths, a hospital mortality of 12.5%. and 10 late deaths, a postoperative mortality of 9.5%. Actuarial analysis has shown a four-year postoperative survival of 78.970.     

Comparative analysis of isolated aortic valve replacement with fascia lata and homograft valves

Thirty-eight consecutive patients who underwent isolated replacement of the aortic valve with fascia lata in 1970 were compared with a similar series of patients undergoing homograft replacement of the aortic valve. These series were well matched in number, age sex of patients, symptomatology, valvular disease, electrocardiographic and roentegenographic changes, and preoperative cardiac catheterization data. The mean follow-up time was 73 months in the fascia lata series and 69.1 months in the homograft series, and all the post-operative survivors were reviewed. The early and long-term results were similar of the two series, and there was no statistical difference in the operative and late mortality, the incidence of early and late diastolic murmurs, valve failure necessitating valve replacement, infective endocarditis, thromboembolism, over-all survival, and survival with an intact valve. It is concluded that the long-term results of valve replacement using these two tissues, in the aortic position, are similar and there is little to choose between the two types of valves. If fascia lata, as we believe, is no longer acceptable as a satisafactory valve substitute, then homograft valves are not acceptable either.     

Long-term follow-up of viable frozen aortic homografts. A viable homograft valve bank

There is currently a renewed interest in the use of both fresh and commercially available frozen homograft valves for children and young adults. This has prompted us to review a series of 32 patients who received frozen homograft valves for aortic replacement between 1973 and 1975. The cryogenic technique evolved to include the use of selected antibiotics and equilibrated dimethyl sulfoxide solution to freeze homografts at a rate of 1 degrees C per minute to liquid nitrogen temperatures of -196 degrees C. Histologic sections of experimental frozen valves explanted 6 months postoperatively revealed the presence of viable donor cells, and tissue culture demonstrated the reproductive capacity of cusp fibroblasts. Of the 32 frozen viable homografts implanted in this series, 23 were inserted as free-sewn aortic replacements and nine were premounted on stents before implantation in the aortic position. There were two operative deaths, and three valves failed as a result of the technical problems of mounting in one patient and surgical insertion of a free graft in two patients. Of the 22 patients who remained at long-term risk, 13% with free-sewn grafts and 57% with premounted valves underwent reoperation for valve failure. After 10 years of follow-up, 15 (68%) of these patients, 12 (80%) with free-sewn and three (43%) with premounted valves, are alive with their original valve in place. Actuarial analysis shows that 58% of the 32 valves implanted are functional at the beginning of the eleventh year. There have been six late deaths resulting in an overall actuarial patient survival rate of 79% at 10 years and 69% after 13 years. These clinical results are believed to add support to our current application of the frozen homograft in selected patients.     

Clinical experience with heart valve homografts in Brazil

The purpose of this paper is to describe the development and progress of the first heart valve homograft bank in Brazil as well as to report the 5-year clinical results. The bank was started in 1995 and employs modern techniques of cryopreservation. Organ procurement increased from 11 hearts in 1995 to 138 hearts in 2000. In the beginning of the experience, only 2 hospitals were using these valves, but this increased to 18 centers in 2000. Clinical experience at the major center includes 117 cases of the Ross procedure, 62 aortic homograft implantations, and 18 cases of mitral homografts. Five-year survival after the Ross procedure was 99.1%, and survival free from any kind of complication was 88.8%. No patients are on anticoagulants, and the incidence of thromboembolism was null. We conclude that auto- and homografts are probably the best alternative to aortic valve replacement for young patients in developing countries.     

Aortic root replacement using a homograft for recurrent valve endocarditis

Prosthetic valve endocarditis is a relatively rare condition associated with high mortality. Endocarditis affecting 2 successive mechanical valves at the aortic position has not, to the best of our knowledge, been described. We reported such a patient whose condition was further complicated by mitral regurgitation, pulmonary hypertension, worsening heart failure, and cardiac conduction abnormalities. Considering the failure of 2 previous mechanical valves, we conducted a homograft replacement of the aortic root with coronary reattachment. Mitral regurgitation was treated by annuloplasty. The patient's early postoperative course was uneventful and he was doing well 16 months after surgery. We discuss the overall treatment strategy for recurrent prosthetic valve endocarditis and potential homograft advantages.     

Cryopreserved aortic homograft replacement in 3 patients with noninfectious inflammatory vascular disease

OBJECTIVE: Although mechanical prosthetic heart valves are most commonly used for aortic valve replacement in patients with aortic regurgitation due to noninfectious inflammatory vascular disease, postoperative perivalvular leakage and/or detachment of the prosthetic valve occurs due to the fragility of the aortic annulus. Aortic root replacement with cryopreserved homografts is reported to be useful in such patients. METHODS: Three patients having aortic regurgitation associated with severe long standing noninfectious inflammatory vascular disease-2 patients with Takayasu's arteritis and 1 patient with Beh?et disease--had the aortic root replacement by a cryopreserved aortic homograft valve and conduit. RESULTS: All surgery was successful and the postoperative course uneventful. Echocardiography showed neither aortic regurgitation nor graft detachment at 6-39 months after operation. CONCLUSIONS: Homograft valve and conduit replacement is appropriate in patients with aortic regurgitation associated with noninfectious inflammatory vascular disease, with mid-term results favorable.     

Surgical Treatment of Prosthetic Valve Endocarditis with Homograft Aortic Valve Replacement

This article presents the University of Alabama experience with homograft aortic valve replacement for prosthetic valve endocarditis. Of 117 patients who have undergone homograft aortic valve replacement since 1981, there has been a total of 22 patients who underwent operation for endocarditis. Sixteen were isolated valve replacements, three combined with other procedures, and three were aortic root replacements. When placed in a setting of active endocarditis, there have been no reoperations for endocarditis of the homograft valve. Surgical techniques are presented for the freehand sewn homograft as well as aortic root replacement. Prosthetic valve endocarditis is a highly lethal event and when aortic valve replacement is advised in this setting, we believe a homograft aortic valve should be implanted whenever possible.     

Ten Years' Experience with Pulmonary Autograft Replacements for Aortic Valve Disease

Pulmonary autograft valves have been used to replace isolated, diseased aortic valves for 10 years, with a long-term survival of 73%. The low incidence of degeneration supports the principle that the autograft valve is a potentially permanent valve replacement. Operative mortality is now less than 5%, despite the longer, more complex operation. The current use of fresh homograft valves for the pulmonary replacement has contributed to these excellent long-term results.     

Viable cryopreserved aortic homograft for aortic valve endocarditis and annular abscesses

Six consecutive patients with active aortic valve endocarditis, including 2 with extensive subannular aortic root abscess, were successfully treated with viable cryopreserved homograft aortic valve replacement. Two patients required extensive aortic root reconstruction with an appropriately trimmed aortic homograft to cover large abscess cavities. All patients showed resolution of infection with no perioperative mortality or clinically significant morbidity. Three patients had a minor degree of aortic insufficiency on postoperative echo-Doppler study. On follow-up at 6 to 48 months, all patients were in New York Heart Association functional class I. The resistance of the unstented homograft to infection makes it an attractive choice for patients requiring aortic valve replacement for active endocarditis. The results of surgical intervention in patients with extensive aortic root involvement may be further improved by the flexibility afforded by the homograft to be "custom-fit" to the abnormal aortic root and the ability to achieve secure abnormal aortic root and the ability to achieve secure valve fixation without use of prosthetic material.     

Design and fabrication of three-dimensional scaffolds for tissue engineering of human heart valves

We developed a new fabrication technique for 3-dimensional scaffolds for tissue engineering of human heart valve tissue. A human aortic homograft was scanned with an X-ray computer tomograph. The data derived from the X-ray computed tomogram were processed by a computer-aided design program to reconstruct a human heart valve 3-dimensionally. Based on this stereolithographic model, a silicone valve model resembling a human aortic valve was generated. By taking advantage of the thermoplastic properties of polyglycolic acid as scaffold material, we molded a 3-dimensional scaffold for tissue engineering of human heart valves. The valve scaffold showed a deviation of only +/-3-4% in height, length and inner diameter compared with the homograft. The newly developed technique allows fabricating custom-made, patient-specific polymeric cardiovascular scaffolds for tissue engineering without requiring any suture materials.     

An experience with the Ross operation utilizing cryopreserved pulmonary homografts procured by and stored in our homograft valve bank

Eight patients, 4 males and 4 females ranging in age from 10 to 54 years (mean 27 +/- 13 years) underwent the Ross operation using a cryopreserved pulmonary homograft harvested by and cryopreserved in our institutional "Tissue Bank". Seven patients had a congenital bicuspid aortic valve and 3 patients had had healed infective endocarditis of the aortic valve. Four young female patients wanted to have a baby after operation. The Ross procedure was carried out utilizing aortic root replacement techniques in all patients. All patients survived and are currently in NYHA class 1, but 2 cardiac events occurred in 2 patients during the mean follow-up term of 29 +/- 19 months. The one was the anastomic stenosis between the homograft and distal pulmonary artery treated by balloon dilatation and the other was ventricular tachycardia eventually managed by the insertion of an ICD. Pulmonary autograft valve regurgitation is present in 3 patients, but it is not progressive up to the present time. Pulmonary homograft valves function well in all patients. The Ross operation for adolescents and young adults should become more popular along with more easy availability of homograft valves based upon the establishment of the "Homograft Valve Bank" system in Japan.     

Platelet survival in patients with homograft and prosthetic heart valves: Correlation with incidence of thromboembolism

Manohitharajah, S. M., Rahman, A. N., Donnelly, R. J., Deverall, P. B., and Watson, D. A. (1974).Thorax, 29, 639-642. Platelet survival in patients with homograft and prosthetic heart valves. Investigations in the past have demonstrated shortened platelet survival time in patients with prosthetic heart valves. This suggested that platelets contribute to thromboembolism in this group. Homograft valves and the newer models of the Starr-Edwards prosthesis have proved less thrombogenic than those previously employed, but platelet survival studies in patients with these valves are lacking. In this study platelet function, survival, and its relation to haemolysis were determined in 28 patients following mitral valve replacement and in two patients following mitral valvotomy: 14 patients had a frame-mounted homograft aortic valve; 13 patients had a Starr-Edwards prosthesis model 6310 or 6320, and one had a Starr-Edwards prosthesis model 6000. Normal platelet function and survival was found in both the homograft and the Starr valve groups. The patient with the earlier model of the Starr valve (model 6000) had a shortened platelet survival time. The two patients following mitral valvotomy had normal platelet survival. The fact that platelet abnormalities were not demonstrable in our patients with homograft valves and newer Starr-Edwards prostheses may explain the low incidence of thromboembolism in this group. Platelet survival studies are a useful parameter to determine the potential thrombogenic nature of prosthetic valves. Platelet survival time was not influenced by the presence or severity of haemolysis.     

The Konno aortoventriculoplasty for repeat aortic valve replacement

Objective: To evaluate the outcome of aortic root augmentation by the Konno-aortoventriculoplasty technique as part of reoperative aortic valve replacement. Methods: Since 1983, 15 patients, 12 males and three females, had repeat aortic valve replacement (AVR) with concomitant Konno aortoventriculoplasty. Age ranged from 1.2 to 18 years (mean 12.5 years). The underlying anatomic diagnoses were valve and subvalvar aortic stenosis in 11, truncal valve insufficiency in one, endocarditis in one, Shone's complex in one and severe aortic insufficiency associated with a ventricular septal defect in one patient. All patients had had previous AVR. The causes for reoperation were prosthetic valve stenosis due to growth in ten and paravalvular leak in one, homograft failure in two, xenograft failure in one, and left ventricular outflow tract obstruction (LVOTO) after mitral valve replacement in one patient. The mean size of explanted prostheses was 19.2 mm (13–23 mm) while the mean size of the implanted prostheses was 24.3 mm (19–27 mm) (P<0.01). Previous aortic root enlargement had been performed in 11 patients in conjunction with AVR. The Manougian technique was used previously in two, Konno aortoventriculoplasty in eight, and both techniques in one patient. The newly implanted aortic valves were a homograft in one patient and mechanical prostheses in 14 patients. Results: There was one operative death (1 of 15 or 6.6%) in a 17.5 year old patient with previous AVR and posterior root enlargement, due to low cardiac output state. Follow-up ranged from 6 months to 17 years (mean 7.2 years). The only late death occurred in an 11.6-year-old patient due to prosthetic valve endocarditis. Two patients had complete heart block and had permanent pacemaker insertion (2 of 15 or 13.3%). One patient had pulmonary valve replacement because of combined stenosis and insufficiency 5 years after operation. All 13-surviving patients are asymptomatic at latest follow up. Conclusion: Konno aortoventriculoplasty with repeat AVR may be safely performed. Excellent results may be achieved despite previous aortic root enlargement. It is a good surgical option for complex LVOTO and may even reduce reoperation in children by allowing placement of a larger prosthesis.     

Short-term result of aortic valve replacement with cryopreserved homograft valve in the University of Tokyo Tissue Bank

The short-term results after aortic root replacement with 11 cryopreserved aortic homografts was examined. Since 1998, the University of Tokyo Tissue Bank has supplied 11 aortic homograft valves. Nine of the recipients were male, and the average age was 51.2 years. Nine out of 11 patients had suffered from a serious condition of native or prosthetic valve infectious endocarditis. All of the patients underwent aortic root replacement, and the blood type between the patient and the homograft was matched in 8 of the patients. Only 1 patient died (9.1%) in the short-term due to sepsis. The preoperative degree of aortic valve regurgitation in all of the cases was third or fourth while the regurgitation disappeared after the operation in all of them. Thinking of the serious condition of our cases preoperatively, the 9.1% operative mortality was quite acceptable. Long-term follow-up is necessary to estimate the quality of the homografts.     

Aortic Valve Replacement with Biological Substitute

Abstract In the quest for an ideal aortic valve substitute, homografts and autografts are well-established options. We reviewed our results with homografts and autografts for aortic valve replacement during the last 5 years. From March 1992 through July 1997,189 patients (138 male and 51 female), age 8 months to 68 years (mean 31.0 2 4.2 years), underwent aortic valve replacement with a human biological substitute. Of these, 93 patients received a cryopreserved or antibiotic-preserved aortic/pulmonary homograft, whereas 96 patients underwent a Ross procedure. Etiology was rheumatic in 143 (75.6%) patients, bicuspid aortic valve in 40 (21.2%, Marfan's disease in 5 (2.6%), and myxomatous aortitis in 1 (0.5%). Among the homograft group, a scalloped subcoronary implantation technique was used in 54 patients, whereas 32 patients underwent root replacement. Five patients required aortic root and ascending aortia replacement for annuloaortic ectasia. In all patients undergoing the Ross procedure, a root replacement technique was used. Operative mortality was 7.4% (14 patients). Late mortality was 5.3% (10 patients). Follow-up ranged from 1 to 46 months postoperatively. In patients with homograft aortic valve replacement, 76 patients (91.5%) had trivial to mild aortic regurgitation, while 7 patients (8.4%) had important aortic regurgitation. In patients with the Ross procedure, 78 patients (89.6%) had trivial to mild regurgitation. Moderate to severe aortic regurgitation was present in 9 patients (10.3%). all of whom had rheumatic heart disease and were young (< 30 years at surgery). We conclude that homografts and autografts provide an excellent substitute for the diseased aortic valve. Young age (< 30 years) with rheumatic etiology is a major risk factor for early progressive aortic regurgitation in patients undergoing the Ross procedure.( J Card Surg 1998;13:1–8)     

Comparison of biomechanical and structural properties between human aortic and pulmonary valve.

OBJECTIVE: Pulmonary valve autografts have been reported as clinically effective for replacement of diseased aortic valve (Ross procedure). Published data about pulmonary valve mechanical and structural suitability as a long-term substitute for aortic valve are limited. The aim of this study was to compare aortic and pulmonary valve properties. METHODS: Experimental studies of biomechanical properties and structure of aortic and pulmonary valves were carried out on pathologically unchanged human heart valves, collected from 11 cadaveric hearts. Biomechanical properties of 84 specimens (all valve elements: cusps, fibrous ring, commissures, sinotubular junction, sinuses) were investigated using uniaxial tensile tests. Ultrastructure was studied using transmission and scanning electron microscopy. RESULTS: Ultimate stress in circumferential direction for pulmonary valve cusps is higher than for aortic valve (2.78+/-1.05 and 1.74+/-0.29 MPa, respectively). Ultimate stress in radial direction for pulmonary and aortic cusps is practically the same (0.29+/-0.06 and 0.32+/-0.04 MPa, respectively). In ultrastructural study, different layout and density in each construction element are determined. The aortic and pulmonary valves have common ultrastructural properties. CONCLUSIONS: Mechanical differences between aortic and pulmonary valve are minimal. Ultrastructural studies show that the aortic and pulmonary valves have similar structural elements and architecture. This investigation suggests that the pulmonary valve can be considered mechanically and structurally suitable for use as an aortic valve replacement.     

Medium-term results of aortic valve replacement with cryopreserved homograft valves: importance of a domestic homograft valve bank

There are advantages to using aortic homografts as aortic valve replacements (AVR), particularly in patients with complex infective endocarditis. To determine the importance of a domestic homograft valve bank, our 23 surgical cases of homograft-AVR were reviewed. Since 2000, the Tissue Bank of the National Cardiovascular Center has supplied 23 aortic homograft valves for the treatment of complex aortic valve endocarditis. Fourteen of 23 patients had prosthetic valve endocarditis and 20 patients had an aortic annular abscess. The early mortality rate was 17% (4 patients), in all of whom prosthetic valve replacement had been performed previously. No recurrent endocarditis and no recurrent aortic regurgitation were noted at medium-term follow-up. An aortic homograft valve is the conduit of choice in cases of infective endocarditis and the importance of a domestic homograft valve bank should be recognized.