Long-term durability of the Hancock II porcine bioprosthesis Rizzoli, Giulio; Bottio, Tomaso; Thiene, Gaetano ...
Journal of thoracic and cardiovascular surgery/The Journal of thoracic and cardiovascular surgery/The journal of thoracic and cardiovascular surgery,
07/2003, Volume:
126, Issue:
1
Journal Article
Peer reviewed
Open access
Survival and prosthetic complications of patients receiving the Hancock II second-generation bioprosthesis (Medtronic, Inc, Minneapolis, Minn) in the aortic, mitral, mitral-aortic, and tricuspid ...positions were analyzed at 15 years’ follow-up.
Between May 1983 and December 1993, 212 patients (104 men and 108 women; mean age, 63 ± 9 years; age range, 29-81 years) received 66 aortic, 114 mitral, 26 mitral-aortic, and 6 tricuspid Hancock II valves. Thirty-one percent of patients had previous valve operations, 15% had concomitant cardiac procedures, and 87% were in New York Heart Association class III or IV. Follow-up included 1704 patient-years and was 98% complete, with a median of 9 patient-years (range, 0.013-17.4 years). Forty-six patients were at risk at 14 to 15 years, and 30 were at risk after 15 years.
One hundred twenty-two (57%) of 212 patients died, 20 of them perioperatively. Fifteen-year actuarial Kaplan-Meier survival was 35.2% ± 3.8%, and freedom from valve-related mortality was 84% ± 3.5%, with no difference on the basis of position or age (<65 or ≥65 years). Percentages for freedom from thromboembolism, anticoagulant-related hemorrhage, endocarditis, and paravalvular leak were, respectively, 78.2% ± 4%, 83.5% ± 3.6%, 95.7% ± 2%, and 97.3% ± 1.4%, with no significant difference between the aortic and mitral positions. Freedom from structural valve deterioration was 71.8% ± 5.6%: 88.9% ± 6.2% in the aortic position versus 59.5% ± 3.9% in the mitral position (
P = .01) and 64.3% ± 3% in the mitral-aortic position. In patients younger than 65 years, actual freedom from structural valve deterioration was less than that seen in older patients (84.5% ± 3.5% vs 95% ± 3.0%) and was better in the aortic versus the mitral position (92% ± 4.5% vs 82% ± 4.2%).
The Hancock II porcine valve showed excellent 15-year durability. We recommend its use in patients 65 years of age, as well as in younger patients undergoing aortic replacement.
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Hancock II bioprosthesis: A glance at the microscope in mid–long-term explants Bottio, Tomaso; Thiene, Gaetano; Pettenazzo, Elena ...
Journal of thoracic and cardiovascular surgery/The Journal of thoracic and cardiovascular surgery/The journal of thoracic and cardiovascular surgery,
07/2003, Volume:
126, Issue:
1
Journal Article
Peer reviewed
Open access
The Hancock II bioprosthesis is a second-generation porcine valve xenograft treated with the detergent sodium dodecyl sulphate (T6) to retard calcification. The aim of this investigation was to study ...the gross and microscopic features in Hancock II explants to assess the structural changes occurring with time.
Among 1382 Hancock II bioprostheses (701 isolated aortic, 421 isolated mitral, 130 double) implanted from 1983 to 1997 in 1252 patients, 22 (16 mitral, 6 aortic) were removed at reoperation until 1999 and were available for pathological investigation
: infective endocarditis occurred in 5 and structural deterioration in 8, whereas in the remaining 9 xenografts reoperation was performed for nonstructural valve deterioration (paravalvular leak in 4 and prophylactic replacement in 5). Morphological investigation consisted of gross examination and x-ray, histologic, immunohistochemistry, electron microscopic, and atomic absorption spectroscopic examination.
The cause of structural valve deterioration was dystrophic calcification in 4 cases (1 aortic, 3 mitral; range of time graft was in place, 101 to 144 months), non-calcium–related tears in 3 cases (all mitral, range 121 to 163 months), and commissural dehiscence in 1 (aortic, range 156 months). Five of the nonstructural valve deterioration explants (range 42 to 122 months) showed only pinpoint mineralization at the commissures. Mean calcium content in nonstructural deterioration explants was 14.70 ± 22.33 versus 99.11 ± 81.52 mg/g in explants with structural valve deterioration. Electron microscopic examination showed early nuclei of mineralization mostly consisting of calcospherulae upon cell debris. Local or diffuse lipid insudation was observed in all but 2 explants and consisted of cholesterol clefts, lipid droplets, and lipid-laden macrophages featuring foam cells. The lipid insudation was the most plausible cause of tearing in 2 explants.
These pathologic findings support the clinical results of a delayed occurrence of structural failure of Hancock II bioprostheses and a mitigation of mineralization by the anti-calcification treatment. However, other factors such as lipid insudation may come into play in the long term.
The participation of endothelin-1 (ET-1) in the control of vascular tone in humans has been questioned, on the basis of the finding of subthreshold immunoreactive (ir) ET-1 plasma levels. However, ...because most ET-1 is secreted abluminally, it might attain a higher concentration in the tunica media than in plasma. Furthermore, evidence indicates that vascular smooth muscle cells (VSMCs) can synthesize ET-1 on stimulation in vitro. We therefore looked for irET-1 in the different layers of the wall of human arteries, including renal, gastric, and internal thoracic artery wall, obtained ex vivo from consenting patients with coronary artery disease and/or high blood pressure undergoing surgery, as well as from young organ donors.
We performed immunohistochemistry with specific anti-ET-1 and anti-vWF antibodies followed by detection with an avidin-biotin complex ultrasensitive kit. The presence of preproET-1 and human endothelin-converting enzyme-1 (hECE-1) mRNA was also investigated by reverse transcription-polymerase chain reaction in homogenates of vessel wall, including preparations deprived of both endothelium and adventitia, and in isolated VSMCs. We detected irET-1 in the endothelium of all arteries and in the tunica media of internal thoracic artery from most patients with coronary artery disease. PreproET-1 and hECE-1 mRNA was also detected in VSMCs isolated from these vessels. irET-1 and irvWF staining in endothelium and tunica media was measured by use of microscope-coupled computer-assisted technology. Significant correlations between the amount of irET-1 in the tunica media and mean blood pressure (P<0.05), total serum cholesterol (P<0.05), and number of atherosclerotic sites (P<0.001) were found. Thus, in organ donors, irET-1 was detectable almost exclusively in endothelial cells, whereas in patients with coronary artery disease and/or arterial hypertension, sizable amounts of irET-1 were detectable in the tunica media of different types of arteries. In addition, VSMCs isolated from these vessels coexpressed the preproET-1 and hECE-1 genes.
Collectively, these findings are consistent with the contention that endothelial damage occurs in most patients with atherosclerosis and/or hypertension and that ET-1 is synthesized in VSMCs of these patients.
Structural and phenotypic changes of cardiomyocytes characterize atrial fibrillation. We investigated whether changes in the glucose-regulated protein GRP94, which is essential for cell viability, ...occur in the presence of chronic atrial fibrillation.
Samples of fibrillating atrial myocardium obtained from both goat and human hearts were analyzed for GRP94 expression by an immunologic approach. In goats, atrial fibrillation was induced and maintained for 2, 4, 8, and 16 weeks. After 16 weeks of atrial fibrillation, cardioversion was applied and followed by 8 weeks of sinus rhythm. GRP94 levels doubled in goat atrial myocytes after 4 to 16 weeks of fibrillation with respect to normal atria and returned to control levels in atrial myocardium of cardioverted goats. Immunohistochemical analyses confirm that GRP94 increase occurred within cardiomyocytes. Significantly, increased levels of GRP94 were also observed in samples from human fibrillating atria. In the absence of signs of myocyte irreversible damage, the GRP94 increase in fibrillating atria is comparable to GRP94 levels observed in perinatal goat myocardium. However, calreticulin, another endoplasmic reticulum protein highly expressed in perinatal hearts, does not increase in fibrillating atria, whereas inducible HSP70, a cytoplasm stress protein that is expressed in perinatal goat hearts at levels comparable to those observed in the adult heart, shows a significant increase in chronic fibrillating atria.
Our data demonstrate a large, reversible increase in GRP94 in fibrillating atrial myocytes, which may be related to the appearance of a protective phenotype.
Intracoronary artery shunt: An assessment of possible coronary artery wall damage Gerosa, Gino; Bottio, Tomaso; Valente, Marialuisa ...
Journal of thoracic and cardiovascular surgery/The Journal of thoracic and cardiovascular surgery/The journal of thoracic and cardiovascular surgery,
05/2003, Volume:
125, Issue:
5
Journal Article
Background. Incidence of tricuspid prosthesis replacement was 1.9% of all valvular operations performed between June 6, 1966 and April 18, 1996. Many series report similar figures, but institutional ...experience is limited and the consensus on treatment modalities is lacking.
Methods. One hundred tricuspid operations were performed on 83 patients (46 female). A primary operation was performed in 64 cases, 13 patients had one previous operation, 4 patients had two previous operations, and 2 patients had three previous operations. Seventeen patients required a tricuspid prosthetic valve rereplacement. There were 2 emergent and 17 urgent operations. The New York Heart Association class was IV in 13 patients (mean pulmonary artery pressure, 41 mm Hg), III in 66 patients (mean pressure, 38 mm Hg), and II in 21 patients. The most frequent operation was simultaneous replacement of the mitral and tricuspid valve (41 patients). Seventy biological and 30 mechanical prostheses were used. Total follow-up time was 613 years, mean 7.4 years (median 4.2 years), with a maximum of 27.8 years, and was 92% complete.
Results. Operative mortality was 24%. Survival was 0.54 (0.48 to 0.59, n = 39) at 5 years, 0.38 (0.32 to 0.44, n = 27) at 10 years, 0.31 (0.25 to 0.36, n = 19) at 15 years, 0.29 (0.23 to 0.34, n = 11) at 20 years, and 0.17 (0.098 to 0.26, n = 3) at 25 years. Early mortality was increased from higher New York Heart Association class (hazard ratio = 2.2), congenital disease (hazard ratio = 6.9), and valvuloplasty failure (hazard ratio = 4.3). The constant risk phase (4%/patient-year) after 2 years was enhanced by older operative age (hazard ratio = 1.4). Prosthetic type had no independent effect. Biological prostheses were at risk for 300 years and had a reoperation incidence of 4.7%/patient-year (14 events); mechanical prosthesis were at risk for 137 years with a rate of 2.2%/patient-year (3 events) (
p = 0.21). Three valve thromboses were observed in old-design mechanical prosthesis. Bioprosthetic degeneration showed a steeper rate after 7 years.
Conclusions. This study does not show a clear superiority of biological versus mechanical prostheses. In the long run survival with mechanical prostheses could be superior, given the high rate of bioprosthetic degeneration after 7 years.
This report describes our experience with primary correction of tetralogy of Fallot in infants.
Fifty-one consecutive infants younger than 6 months underwent primary correction of tetralogy of Fallot ...between January 1978 and October 1994. Mean age at repair was 4.2 months. Four were neonates. Correction was accomplished through a right ventriculotomy in the first consecutive 22 patients (43%; group A); since 1991, a combined transatrial-transpulmonary approach was used in 29 consecutive patients (57%; group B). A transannular patch was necessary in 33 infants (65%) 16 of group A (73%) and 17 of group B (59%).
There was one early death from possible left anterior descending coronary artery distortion in group A and no deaths in group B. Two patients required early reoperation for systemic-to-pulmonary artery collateral ligation (postoperative day 6) and permanent pacemaker implantation (postoperative day 30). There were no late deaths. All 50 survivors are currently asymptomatic and in New York Heart Association class I. Three patients required late reoperations 36 months, 30 months, and 13 months after repair for (1) subaortic stenosis and dysfunctioning dysplastic mitral valve, (2) residual pulmonary artery branch stenosis, and (3) residual right ventricular outflow obstruction. Four patients underwent balloon dilation and stent insertion (1 patient) for peripheral pulmonary artery stenosis 1.5 year to 12 years (mean, 5 years) after initial repair. Actuarial freedom from need for reintervention at 4 years was 78.4% in group A and 85.7% in group B. Two-dimensional and Doppler echocardiographic follow-up studies showed a residual mild to moderate pulmonary artery branch stenosis in 4 patients in group A, and a recurrent subaortic stenosis in 1 patient in group A. Right ventricular peak systolic pressure was less than 40 mm Hg in all but 3 asymptomatic patients who had a residual pulmonary artery branch stenosis. Right ventricular end-systolic and end-diastolic volumes showed larger volumes and reduced ejection fraction in group A compared with group B.
This limited experience with repair of tetralogy of Fallot in patients less than 6 months of age demonstrates that the transatrial-transventricular approach is possible in neonates and young infants with a very low mortality and morbidity and also a low incidence of residual lesions. Follow-up echocardiographic data suggest that right ventricular function is better preserved in those patients who underwent the transatrial-transpulmonary repair.
Hemodynamic performances of mechanical valve prostheses in patients with aortic valve stenosis and a small aortic annulus are crucial. We analyzed the in vitro hydrodynamics of 5 currently available ...bileaflet mechanical prostheses that fitted a 21-mm-diameter valve holder of a Sheffield pulse duplicator.
Three samples of 5 high-performance production-quality prostheses, including the sewing ring cuffs, were tested in the aortic chamber of a Sheffield pulse duplicator. Sizes of the prostheses fitting the 21-mm valve holder were as follows: 18-mm ATS, 19-mm SJM Regent, 19-mm Sorin Bicarbon Slimline, 19-mm On-X, and 21-mm Carbomedics Top Hat. The tests were carried out at a fixed pulse rate (70 beats/min) and at increasing cardiac outputs of 2, 4, 5, and 7 L/min. Each valve was tested 10 times for each different cardiac output. This resulted in a total of 40 tests for each valve and 120 tests for each valve model. The aortic pressure was set at 120/80 mm Hg (mean pressure, 100 mm Hg) throughout the experiment for all cardiac outputs. Forward flow pressure decrease, total regurgitant volume, closing and leakage volumes, effective orifice area, and stroke work loss were recorded while the valve operated under each cardiac output.
The SJM Regent valve and the Sorin Bicarbon Slimline prosthesis showed the lowest mean and peak gradients at increasing cardiac outputs. The closure volume was higher for the SJM Regent and Sorin Bicarbon Slimline prostheses, unlike with the ATS prosthesis at 7 L/min of cardiac output. The ATS and SJM Regent prostheses showed the largest regurgitant volume, whereas the Sorin Bicarbon Slimline prosthesis showed the lowest regurgitant volume. The calculated effective orifice area and stroke work loss were significantly better with the SJM Regent and Sorin Bicarbon Slimline prostheses.
Assuming that the 21-mm valve holder in which all the tested prostheses were accommodated is comparable with a defined aortic valve size, this hydrodynamic evaluation model allowed us to compare the efficiency of currently available valve prostheses, and among these, the SJM Regent and the Sorin Bicarbon Slimline exhibited the best performances.
We describe the angiographic characteristics of coronary artery spasm observed in 12 out of 247 (4.9%) patients who underwent 808 coronary angiographies after heart transplantation. Coronary artery ...spasm was diagnosed when localized and reversible narrowing of the coronary lumen was identified. After coronary artery spasm identification all patients were followed-up clinically for a mean period of 5.1 years. Coronary artery spasm was documented 1–3 years after heart transplant. Coronary artery spasm affected 1 main coronary artery in 10 patients and 2 in 2 patients; in 3 patients 1 or more secondary branches were also affected. The right coronary artery was affected by coronary artery spasm in 8 patients and the anterior descending coronary artery in 6 patients. In 6 patients coronary artery spasm was mechanically induced by the catheter tip. The degree of luminal narrowing due to coronary artery spasm ranged from mild to almost complete occlusion. Coronary artery spasm appeared as a single tubular smooth and concentric stenosis in 8 patients, was discrete in 2 patients and multiple on the same vessel in 2 patients. In 1 patient coronary artery spasm was erroneously interpreted as an organic lesion and percutaneous transluminal coronary angioplasty was planned. During follow-up 3 patients out of 4 who had shown multiple coronary artery spasm died and 2 patients developed critical organic stenosis. In conclusion coronary artery spasm after heart transplant is less rare than commonly believed. Although it usually has a peculiar appearance, it can be misinterpreted as an organic lesion. Multiple coronary artery spasm appears to carry a poor prognosis.
Heart valve bioprostheses for cardiac valve replacement are fabricated by xeno- or allograft tissues. Decellularization techniques and tissue engineering technologies applied to these tissues might ...contribute to the reduction in risk of calcification and immune response. Surprisingly, there are few data on the cell phenotypes obtained after cellularizing these naturally-derived biomaterials in comparison to those expressed in the intact valve.
Aortic valve interstitial cells (VIC) were used to repopulate the corresponding valve leaflets after a novel decellularization procedure based on the use of ionic and nonionic detergents. VIC from leaflet microexplants at the third passage were utilized to repopulate the decellularized leaflets. Intact, decellularized and repopulated valve leaflets and cultured VIC were examined by immunocytochemical procedures with a panel of antibodies to smooth muscle and nonmuscle differentiation antigens. Intact and cellularized leaflets were also investigated with Western blotting and transmission electron microscopy, respectively.
Myofibroblasts and smooth muscle cells (SMC) were mostly localized to the ventricularis of the leaflet whereas fibroblasts were dispersed unevenly. Cultured VIC were comprised of myofibroblasts and fibroblasts with no evidence of endothelial cells and SMC. Two weeks after VIC seeding into decellularized leaflets, grafted cells were found penetrating the bioscaffold. The immunophenotypic and ultrastructural properties of the grafted cells indicated that a VIC heterogeneous mesenchymal cell population was present: fibroblasts, myofibroblasts, SMC, and endothelial cells.
VIC seeding on detergent-treated valve bioscaffolds has the cellular potential to reconstruct a viable aortic valve.
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