Long-term results of porcine bioprosthetic valves

Between November 1977 and October 1980, 54 patients underwent valve replacements with porcine bioprostheses at Hyogo Kenritsu Amagasaki Hospital. The late complications and the long term durability of 53 porcine bioprostheses were documented in 48 patients after discharge (34 mitral, 7 aortic, 2 tricuspid, and 5 multiple, consisting of 38 Hancock, 15 Carpentier-Edwards prostheses). Cumulative duration of follow-up is 420 patient-years. The valve related late mortality was 0.52%/patient-years. There were 6 thromboembolic events (1.6% patient-years), only 1 episode of endocarditis (0.26%/patient-years). Valve dysfunction is defined as stenosis or regurgitation by echocardiogram or cardiac catheterization. There were 21 instances of porcine bioprosthetic dysfunction (6.6% patient-years). Freedom from valve dysfunction at 12 years was 24.4%. There were 17 valves of mitral bioprosthetic dysfunction (6.4% patient-years). The incidences of mitral stenosis (MS), mitral regurgitation (MR), and paravalvular leakage were 4.5, 3.6, and 0.7%/patient-years respectively. Freedom from MR was higher than MS at 8 years. The 14 patients were needed reoperation due to valve dysfunction (3.6%/patient-years). We concluded that the porcine bioprostheses showed a high incidence of valve dysfunction at 7 to 8 years after operation, we presently choose mechanical valve in most cases.     

Late results with bioprosthetic valves in the elderly

AIM: We report the long-term outcome of aortic and mitral bioprostheses in patients over 65 years of age at the time of implantation. The aim was to determine actuarial patient survival, causes of death, and the rate of documented primary structural deterioration. METHODS: One hundred ten patients > or = 65 years of age (mean, 73.4; range, 65-82) underwent successful bioprosthetic valve replacement (aortic, n = 71; mitral, n = 32; both, n = 7) from 1979 to 1985. The valve was pericardial in 39 cases and porcine in 78. The mean follow-up was 8.5 years (101.9 months-total; 934 patient-years; range, 2 months to 15 years). RESULTS: Actuarial patient survival was 79.6% (71-86) at 5 years and 62.4% (52-71) at 10 years. Forty-four patients died, 21 from valve-related causes and 23 from other causes. Thirteen patients (11.8%) had reoperation for valve-related complications: 10 structural deteriorations, 2 paravalvular leaks, and 1 case of endocarditis. One surgical death occurred (7.7%). Twenty-six percent of the patients were receiving anticoagulants because of atrial fibrillation, and 6.4% developed severe bleeding (2.9% patient-years). CONCLUSIONS: Long-term follow-up of these patients > 65 years of age, undergoing bioprosthetic value replacement surgery revealed a low rate of documented primary structural deterioration (0.95% per patient-year), a low mortality rate on reoperation (7.7%), and a high mortality rate due to non-value-related causes (52.3%).     

Percutaneous stent implantation to stenotic bioprosthetic valves in the pulmonary position

BACKGROUND: We evaluated stent implantation across stenotic bioprosthetic pulmonary valves in 9 patients. METHODS: Nine patients (6 male patients) underwent stent implantation across stenotic bioprosthetic pulmonary valves between July 1996 and July 1999 at the Hospital for Sick Children, Toronto. Catheter intervention was indicated if echocardiography revealed Doppler estimates of right ventricular pressure of more than two thirds of systemic arterial pressure (or systolic septal flattening with an estimated gradient of >60 mm Hg across the valve prosthesis). Catheterization was performed during general anesthesia at an age (mean +/- SD) of 9.3 +/- 3.5 years and a weight of 32.0 +/- 17.1 kg 5.9 +/- 1.8 years after surgical insertion of a bioprosthetic valve in the pulmonary position: 7 patients with tetralogy of Fallot, 1 patient with congenital pulmonary stenosis-insufficiency, and 1 patient after a Rastelli operation. All had systolic septal flattening and right ventricular dilatation with moderate-to-severe pulmonary insufficiency before intervention. Fluoroscopy times were 33.1 +/- 9.5 minutes. Seven patients received a single P4014 stent, and 2 received single P308 stents (Palmaz; Johnson & Johnson Interventional Systems, Warren, NJ) without significant complications. RESULTS: The right ventricular systemic pressure decreased acutely from 83% +/- 16% to 41% +/- 10% (P <.001, n = 9), and the transvalvular gradient decreased from 49.7 +/- 8.5 to 11.0 +/- 5.9 mm Hg (P <.001, n = 8). During the follow-up period (10.9 +/- 8.1 months, n = 8), 1 patient had an unsuccessful attempt at redilation of the stent (right ventricular pressure, 60% systemic) and underwent uneventful surgical pulmonary valve replacement. None of the remaining patients had echocardiographic evidence of systolic septal flattening, and right ventricular dimensions did not change significantly. CONCLUSION: Stent implantation is a safe and effective means of providing palliative relief of obstructed bioprosthetic valves in the pulmonary position and can safely delay the requirement for pulmonary valve replacement.     

Comparison of long-term results of Carpentier-Edwards and Hancock bioprosthetic valves

The long-term survival following valve replacement with Carpentier-Edwards or Hancock bioprostheses was compared between the two valve models and between the two groups totaling 407 patients who were discharged after valve replacement beginning in 1974. The two groups of patients were treated in a nonrandomized fashion. The actuarial survival for 299 patients with Carpentier-Edwards valves was 94 +/- 1.5% (+/- standard error) and 93 +/- 1.7% after 5 and 8 years of follow-up, respectively. Comparable figures for 108 patients undergoing valve replacement with Hancock valves were 89 +/- 3.0% and 83 +/- 3.7%, respectively (p = not significant [NS]). The probability of freedom from death and valve removal after 5 and 8 years of follow-up was 91 +/- 1.8% and 79 +/- 4.6%, respectively, with the Carpentier-Edwards valve and 84 +/- 3.5% and 75 +/- 4.3%, respectively, with the Hancock valve (p = NS). An accelerated rate of attrition for both valves was observed in the mitral position. There were no significant differences in actuarial survival between the two valves in the mitral or the aortic position or in the incidence of major valve-related complications.     

生物瓣膜失功能原因分析

目的对植入人体内1年以上损坏的生物瓣膜作损坏原因的临床分析。方法1993年6月至2004年6月,共41例(47只)生物瓣膜失功能病人行再次手术换瓣。两次换瓣间隔时间1~16年,平均(9.7±4.1)年。对失功能生物瓣膜进行标本观察及病理学检测。结果47只带支架生物瓣膜中,瓣架无一损坏,42只瓣膜发生瓣叶撕裂或穿孔,35只有不同程度的钙化现象,且在瓣环表面和瓣脚周围有纤维组织增生,2只瓣膜有赘生物及血栓形成;47只生物瓣膜中损坏较重的瓣膜送病理学检查发现大量吞噬细胞和单核细胞浸润。结论生物瓣膜早期损坏以破损撕裂为主,晚期以钙化和破损撕裂等多种因素的复合病损结果出现。     

Long-term results of homograft valves in extracardiac conduits

Between 1971 and 1986, 335 patients received various extracardiac valved conduits between one of the heart chambers and the pulmonary arteries. The group of patients who received aortic homograft conduits and survived the operation were analysed in detail. The age varied between 9 days and 18 years (mean 7.1 ± 0.7 years), weight 2.4 kg–63.5 kg (mean 17.8 ± 10.8 kg). The diameter of the conduit used was 10–30 mm (mean 20.8 mm). Multivariate analysis revealed a highly significant model (P < 0.005) which showed that the time interval between harvesting and use of the homograft (P < 0.02) and the earlier date of operation (P < 0.05) were the major risk factors for obstruction. Homografts used within 3 weeks of harvesting had freedom from obstruction of 79% at 8 years; homografts used between 3–6 weeks had freedom from obstruction of only 55% at 8 years. Homografts used alone performed significantly better than those extended with woven Dacron tubes. At 10 years, 93% of homografts used alone were free of obstruction compared to 52% of homografts extended with a Dacron tube. We conclude that aortic homografts used within 3 weeks of harvesting provide a reasonably durable conduit for a period of 12 years. Longer storage, and extension of the homograft with a woven Dacron tube should be avoided.     

Long-term results of bioprosthetic mitral valve replacement: the pericardial perspective

Pericardial valve bioprostheses were introduced in early 1970s and were widely used in the 1980s. The longterm results with the Ionescu-Shiley valve, the first commercially available pericardial valve, were disappointing because of high rate cusp tears during the first decade after implantation. The enthusiasm for this type of bioprosthetic valve was further hampered by the premature failure of the Hancock pericardial valve. The long-term results of aortic valve replacement with the Carpentier-Edwards pericardial valve, which was introduced in 1981, indicated that that valve was durable and the issue of cusp tears had been resolved by an appropriate design. This knowledge prompted surgeons to revisit the merits of pericardial valves for mitral valve replacement and several other pericardial valves are now commercially available. The largest data on long-term results are with the Carpentier-Edwards pericardial mitral valve. The reported freedom from structure valve failure ranged from 69% to 85% at 10 years in patient population with mean age of 60 to 70 years. Young age is a major determinant of valve failure, which is largely due to calcification. There are also long-term data, albeit more limited on the Sorin Pericarbon and Mitroflow valves used for mitral valve replacement. This paper review the published experience with various pericardial bioprosthetic valves used for mitral valve replacement during the past 3 decades.     

Long-term results of porcine bioprosthetic heterograft; a 13-years' experience

One hundred and ninety-four patients underwent valve replacements with the glutaraldehyde-preserved porcine bioprostheses (133 Hancock valves, 39 Angell-Shiley valves, 22 Carpentier-Edwards valves and 3 other valves) from 1974 through 1979. There were 105 women and 89 men, whose age ranged 18 to 62 (mean 38.8) years. One hundred and eighty-two patients had mitral bioprosthetic valve replacement (BVR)s, of which 52 had combined aortic mechanical valve replacements, 8 had aortic BVR's, 3 had tricuspid BVR's and 3 had multi-BVR's. Operative mortality was 10.8%. Only one patient was lost to follow-up. Cumulative duration of follow-up is 1421 patient-years. Linearized rate of anticoagulant related hemorrhage, thromboembolism (TE), prosthetic valve endocarditis (PVE), primary tissue failure (PTF) and valve dysfunction (VD) were 0.07, 1.62, 0.49, 2.74 and 3.66% per patient-year. Actuarial freedom from TE, PVE, PTF and VD were 87.0 +/- 2.7%, 95.6 +/- 1.5%, 65.2 +/- 4.9% and 56.9 +/- 5.6% at 13 years. Actuarial survival rate was 67.4 +/- 4.0% at 13 years. Long term follow-up after valve replacement with porcine bioprosthetic valve confirms low thrombogenicity. But primary tissue failure was the chief cause of valve dysfunction and represent a major problem. At this time, we are going to use porcine bioprosthetic valve in the selected patients, that is in the situations in which anticoagulation is contraindicated.     

Long-term clinical results after aortic valve replacement with mechanical heart valves and mitral valve replacement with porcine valves]

Long-term clinical results of aortic valve replacement (AVR) with mechanical heart valves and mitral valve replacement (MVR) with porcine valves were analysed. Sixty-three patients received isolated AVR and 48 received isolated MVR. Sixty-eight patients with MVR including double or triple valve replacement were also added in order to evaluate the primary tissue failure (PTF). The patients with operative deaths were excluded. Survival rate at 11 years in AVR was 68 +/- 10% and 67 +/- 15% in MVR without statistical difference. At 11 years, 76 +/- 8% of the patients in AVR were free from valve-related complications in contrast with the poor result of 34 +/- 31% in MVR (p less than 0.01). Main cause of this poor result in MVR was PTF as indicated in following event free rates; 83 +/- 9% at 7 years, 61 +/- 25% at 10 years and 49 +/- 31% at 13 years. There was no statistical difference between patients of above 50 years and below 49 years in PTF. Valve-related death event free was 93 +/- 5% in AVR and 86 +/- 11% in MVR at 11 years (not significant), however, there was statistical difference in re-operation event free rate as 94 +/- 5% in AVR and 76 +/- 11% in MVR at 11 years (p less than 0.001). These results suggest that the use of porcine valves in mitral position is confined to the selected patients.     

Glutaraldehyde affects biocompatibility of bioprosthetic heart valves.

A marked release of glutaraldehyde from commercially available pericardial bioprosthetic heart valve (BHV) material in washing solutions was found by high performance liquid chromatography (up to 1.8 ppm of glutaraldehyde per gram of dry tissue). In vitro endothelial cell proliferation rate was impaired dose-dependently in the presence of increasing glutaraldehyde concentrations of the cultivation medium (r = 0.9; p less than 0.05). Cultivation of endothelial cells was impossible on the surface of commercially available BHV material, but successful and uninhibited when toxic glutaraldehyde ligands of the BHV material were antagonized by treatment with L-glutamic acid.     

Binding of preformed xenoantibodies to porcine bioprosthetic valves

We have investigated whether preformed antibodies against xenoantigens bind to cellular elements remaining on porcine bioprosthetic valves after various methods of preservation. Fresh porcine valves treated with either acetone, 4% formaldehyde, or 0.625% glutaraldehyde, as well as an unfixed valve, were incubated with antiserum against porcine xenoantigens. This serum was prepared using the affinity purification method with porcine lymphocytes as the target. The valves were stained with secondary fluorescein-conjugated antibody against immunoglobulin M or immunoglobulin G and examined under fluorescent microscopy. Intense binding of immunoglobulin M to the endocardium was observed in the unfixed valve as well as in valves fixed in acetone and formaldehyde. Glutaraldehyde fixation eliminated binding of antibody. Binding was not noted within the connective tissue. No binding of antiimmunoglobulin G was noted on the endocardium of any of the sections. Examination of three glutaraldehyde-treated porcine valves explanted from the aortic position after 10 years in situ showed no immunoglobulin deposition. These results demonstrate the elimination of antigenicity to preformed antibodies in the endocardium and connective tissue of glutaraldehyde-preserved porcine valves. The findings may, in part, explain the poor performance of formaldehyde-preserved bioprosthetic xenograft valves in the past and support the use of glutaraldehyde as a preferred agent for preservation of bioprosthetic endovascular materials.     

Effect of warfarin on calcification of spontaneously degenerated porcine bioprosthetic valves

Synthesis of a calcium-binding amino acid, gamma-carboxyglutamic acid, is a vitamin K-dependent enzymatic process. Warfarin inhibits gamma-carboxyglutamic acid synthesis and, therefore, might diminish the calcification of porcine bioprosthetic valves. To evaluate this, we studied 40 porcine bioprosthetic valves removed because of spontaneous degeneration; 17 patients were treated with warfarin (prothrombin time greater than or equal to 1.5 control) and 23 were untreated. Gross visualization of calcification corresponded closely to x-ray visualization of calcification in explanted valves. No grossly visible calcification or only a single localized nodule was shown in 11 of 17 valves (65%) in treated patients and in only five of 23 valves (22%) in untreated patients (p less than 0.02). Histologic examination showed no calcium or only fine specks of calcium in nine of 13 valves (69%) among warfarin-treated patients and three of 19 valves (16%) from untreated patients. Warfarin, therefore, administered in usual clinical doses, appeared to diminish calcification in spontaneously degenerated porcine bioprosthetic valves.     

Long-term results of mechanical valves in aortic position and biological valves in mitral and tricuspid positions

The long-term results of patients undergoing aortic valve replacement (AVR) with a mechanical valve (AM), mitral valve replacement with a biological valve (MB), and tricuspid valve replacement (TVR) with a biological valve (TB) operated upon from 1977 to 1988 were retrospectively analysed. A total of 899 patients received 1117 valves (381 AM, 633 TB, 103 TB) with a follow-up 3778 patient-years and 4582 valve-years. A significant incidence of thromboembolism, hemorrhage, and endocarditis was not found among AVR, MVR, TVR, or multiple valve replacement. We found a significantly decreased incidence of survival rate in multiple valve replacement compared with AVR or MVR, and a significantly increased incidence of reoperation in MB compared with AM and TB. We use AM and TB in any adult patients as a first choice. However, we prefer a mechanical valve in the mitral position except in patients over 65 years old, who have a short life expectancy, in whom anticoagulation is thought to be difficult, and who desire a biological valve.     

Long-term results of covered stent repair of internal carotid artery dissections

BACKGROUND: Traumatic and spontaneous dissections of internal carotid arteries (ICA) are rare conditions. So far, these pathologies are primarily treated conservatively, surgical revascularization being an option only after recurrent thromboembolic neurologic episodes or continuous aneurysm growth. Successful endovascular treatment strategies with covered stents have been reported in patients with ICA dissections. However, no long-term results are published so far. Herein, we report our experience of a combined conventional and endovascular repair of ICA dissections under reversed flow and their respective long-term results. METHODS: In a prospective evaluation of clinical and morphologic outcome of 6 patients with carotid artery dissections, 2 patients were treated for continuous aneurysm growth and 4 patients for high-grade ICA stenoses with recurrent thromboembolic episodes during a 6-month follow-up period. A 6-mm polytetrafluoroethylene Hemobahn endoprosthesis was inserted under reversed flow of the internal carotid artery. RESULTS: No perioperative strokes were observed; one TIA occurred, lasting less than 3 hours; no peripheral cranial nerve injuries or deaths were observed. No occlusions, hemodynamically significant stenosis, or recurrent neurologic symptoms were seen during follow-up, which ranged from 6 to 54 months (mean, 38.3 months). CONCLUSION: Open endovascular repair of the ICA of symptomatic patients with dissections with a 6-mm covered endoprosthesis is a safe alternative to conventional surgery, with excellent long-term patency.     

Long-term results of endovascular aneurysm repair with aortouni-iliac custom-made stent grafts

The purpose of this study was to review the outcome of endovascular abdominal aortic aneurysm repair (EVAR) using custom-made aortouni-iliac (AUI) devices with femorofemoral bypass. Between June 1999 and March 2001, 23 consecutive patients (1 female, 22 male) at high risk of open aortic aneurysm repair underwent EVAR with custom devices in an AUI configuration. The mean follow-up was 37 months (range 2-72 months), and the mean age was 76.8 years (range 67.5-88.7 years). Increased surgical risk was evidenced by 92% and 69% of patients with significant pulmonary or cardiac disease, respectively. The preoperative mean aneurysm diameter (n = 23) 62 +/- 8.2 mm was significantly greater than the postoperative diameter, (n = 23) 54 +/- 16.4 mm. Ten endoleaks occurred. Migration of the stent graft occurred in 9% (n = 2). Secondary interventions were necessary in 23%, whereas tertiary interventions were required in 9%. Patients at high risk of open aneurysm repair received sufficient protection from aneurysm rupture with custom-made AUI devices.