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How to cite: Bodnar E. (2000). The Silzone dilemma--what did we learn?. The Journal of heart valve disease, 9(2), 170–173.

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How to cite: Mestres, C. A., & Pomar, J. L. (2000). Mitral valve replacement with a pulmonary autograft: initial experience. The Journal of heart valve disease, 9(1), 169.

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How to cite: Love J. W. (2000). Future directions in tissue heart valves: impact of recent insights from biology and pathology. The Journal of heart valve disease, 9(1), 168–169.

Background and aim of the study: Recent reports have given details of early clinical failures of bioprosthetic heart valves manufactured using dye-mediated photooxidized bovine pericardium. These failures were attributed to abrasion of the inflow surface of the leaflets against the cloth-covered inner face of the outer valve frame. These failures had not been detected during preclinical testing of such valves. The aim of this study was to determine if such failure modes could be replicated during fatigue testing of the photooxidized valves, and whether lining of the inflow face of the outer frame with pericardium could eliminate these failures.

Methods: The fatigue properties of six lined and six unlined PhotoFix(R) alpha valves was determined using two Rowan Ash fatigue testers which were cycled at 15 Hz for a maximum of 210 million cycles. The closing pressure within in each chamber was 110+/-10 mm Hg. Each valve was inspected every 40 million cycles for any signs of fatigue failure. All valves were tested to at least 210 million cycles.

Results: In all six lined PhotoFix alpha valves there was no evidence that wear, tear or abrasion of the inflow aspect of the leaflets adjacent to the inflow face of the outer frame had occurred. Only one unlined valve showed any signs of damage adjacent to the outer frame, as evidenced by loss of loose connective tissue, but this did not have the imprint of the cloth covering, which would have suggested actual wear. Effectively, after 200 million cycles, no fatigue failures of either the lined or the unlined PhotoFix alpha valves had occurred. Moreover, the leaflet tears that had been observed clinically were not replicated in this study.

Conclusion: Previous studies have shown a good qualitative, quantitative association between fatigue failure in Rowan Ash accelerated fatigue testers, and clinical experience in glutaraldehyde-treated bovine pericardial valves. The accelerated fatigue tester did not provide an adequate model for the prediction of clinical failure for the photooxidized pericardial valves.

How to cite: Butterfield, M., & Fisher, J. (2000). Fatigue analysis of clinical bioprosthetic heart valves manufactured using photooxidized bovine pericardium. The Journal of heart valve disease, 9(1), 161–167.

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How to cite: Reul, H., & Potthast, K. (2000). The dilemma of accelerated bioprosthetic and polymeric valve testing. The Journal of heart valve disease, 9(1), 159–160.

Background and aim of the study: Human heart valve interstitial cells (ICs) have been understudied to date. The aim of this study was to determine whether valve ICs were uniquely different from pericardial ICs and skin fibroblasts by determining their phenotype and investigating their reactivity.

Methods: ICs were cultured from human heart valves (n = 13), pericardium (n = 4) and skin (n = 4). Cell phenotype was determined by immunofluorescence using a panel of antibodies against surface and cytoskeletal components, and intracellular calcium changes were evaluated by loading the cells with fura-2 acetoxymethyl ester.

Results: Skin fibroblasts expressed virtually no smooth muscle (SM) alpha-actin, whereas, 56.9+/-8.9% (mean +/- SEM) of ICs from valves and 21+/-7.6% of ICs from pericardium expressed SM alpha-actin. ICs from pericardium and skin fibroblasts always expressed a fibroblast surface antigen, whereas expression was variable on valve ICs (80+/-6.9%). All cells expressed prolyl 4-hydroxylase, beta-tubulin and vimentin, but not desmin. Transient increases in intracellular calcium were induced by vasoactive agents: skin fibroblasts were least responsive to all agents.

Conclusions: ICs cultured from heart valves consist of a mixed population of specific cell types, many of which express SM alpha-actin and may be classified as myofibroblasts. The intracellular calcium responses to vasoactive agents indicated that a number of receptor signaling pathways existed. Evaluation of these may help to elucidate the role of myofibroblasts and other fibroblast phenotypes in valve function/dysfunction, as well as contribute to the development of tissue-engineered valves.

How to cite: Taylor, P. M., Allen, S. P., & Yacoub, M. H. (2000). Phenotypic and functional characterization of interstitial cells from human heart valves, pericardium and skin. The Journal of heart valve disease, 9(1), 150–158.

Background and aim of the study: Thrombolysis is an emerging method to open thrombosed prosthetic heart valves. However, its applicability and safety in multiple recurrent thrombotic episodes is unclear.

Methods: Among 16 patients with thrombosed prosthetic valves treated with thrombolysis during a 33-month period, three patients (one mitral and two tricuspid) experienced four episodes each, and these were treated with repeated thrombolytic therapy. Data on patient demographics, clinical presentation, diagnosis, treatment and outcome are presented.

Results: Thrombolysis was successful in 10/12 episodes (83%); there was delayed response in one episode (8%), and partial response in one episode (8%). There were no major complications. However, a fifth thrombotic episode occurred in two patients with tricuspid prostheses, mandating re-do surgery.

Conclusion: Thrombolysis in re-thrombosed prosthetic heart valves is feasible, highly successful and safe, and may therefore be used judiciously in selected patients who could not, or would not, undergo redo surgery. A high recurrence rate in the tricuspid position may implicate earlier surgical intervention, which should be individualized.

How to cite: Shapira, Y., Herz, I., Birnbaum, Y., Snir, E., Vidne, B., & Sagie, A. (2000). Repeated thrombolysis in multiple episodes of obstructive thrombosis in prosthetic heart valves: a report of three cases and review of the literature. The Journal of heart valve disease, 9(1), 146–149.

Background and aim of the study: Mechanical valves are known to produce chronic, subclinical hemolysis in most patients. Generally, haptoglobin is reduced to below normal in most patients, while lactate dehydrogenase (LDH) is increased to as much as 200% above the upper normal, sometimes resulting in anemia. The study was designed to investigate the clinical hemolysis of the On-X(R) prosthetic heart valve in a multicenter experience with a standard protocol and a single clinical laboratory.

Methods: Between September 1996 and August 1998, 248 patients underwent isolated valve replacement at 10 European centers. Blood samples were collected from these preoperatively and at 3-6 months and one year postoperatively. All samples were analyzed at a central laboratory, thus assuring poolability of the data. In total, 151 patients were tested at 3-6 months, and 62 at one year. Blood parameters measured were LDH, haptoglobin, hematocrit, total hemoglobin, red cell count and reticulocyte count. Paired analysis was used to compare preoperative baseline values with 3-6-month and one-year values. Data were analyzed with regard to both valve position and size.

Results: At 3-6 months and one year after surgery, average values for hematocrit, hemoglobin, red cell count and reticulocyte count were all near the center of the normal range, regardless of valve position or size. Statistically significant increases in red cell count and decreases in reticulocyte count occurred after both aortic valve replacement (AVR) and mitral valve replacement (MVR). These changes were of no clinical importance, but indicate that anemia has not occurred in these patients. At 3-6 months, haptoglobin was reduced to below normal in 86% of both AVR and MVR patients; this also occurred after one year and was statistically significant. Postoperatively, the mean LDH value in AVR was 228 U/l (91% of upper normal, 250 U/l) at 3-6 months, and 246 U/l (98% of upper normal) at one year. In MVR, these LDH values were 271 U/l (108% of upper normal) and 265 U/l (106% of upper normal).

Conclusions: These results indicate that the On-X valve causes lower levels of chronic hemolysis in the immediate postoperative period and up to one year after surgery, especially when compared with reports of LDH elevations up to 200% of upper normal. Hemolytic anemia has not occurred in this patient population.

How to cite: Birnbaum, D., Laczkovics, A., Heidt, M., Oelert, H., Laufer, G., Greve, H., Pomar, J. L., Mohr, F., Haverich, A., & Regensburger, D. (2000). Examination of hemolytic potential with the On-X(R) prosthetic heart valve. The Journal of heart valve disease, 9(1), 142–145.

Background and aim of the study: Prosthetic valve endocarditis (PVE) is a serious complication of heart valve replacement. The use of silver-coated polyester fabric in sewing cuff fabrication is intended to reduce the incidence of PVE. In this study, three pathogenic strains of Staphylococcus epidermidis (two PVE and one peripheral vasculature pathogen) were used to evaluate infection of silver-coated and uncoated fabric.

Methods: Fabric was inoculated by preincubation for 30 min in bacterial suspensions containing 10(4), 10(5), 10(6), 10(7) or 10(8) CFU/ml, and implanted subdermally in mice for up to seven days. Bacteria adherent to fabric implanted for zero, one, three, or seven days were enumerated by sonicating the fabric and plating serial dilutions of the resulting suspension. Percent infection was assessed by implanting samples, subdermally, for seven days, then incubating explanted samples in growth media for three days and calculating the percent of fabric showing bacterial growth, for each concentration of inoculum. A logistic regression model was used to estimate curves relating percent infection to log concentration of the bacterial inoculum. These curves were used to estimate the concentration of inoculum required to produce 50% infection (ID50) for the three strains of S. epidermidis, for silver-coated and uncoated fabric.

Results: Direct enumeration showed no difference in bacteria adherent to silver-coated and uncoated fabric, and no bacteria present in either fabric type in samples implanted for seven days. Nevertheless, incubation of those samples in growth media showed that many of the samples were infected. The calculated ID50 was significantly lower for silver-coated fabric than for uncoated fabric, for all three strains of S. epidermidis tested.

Conclusion: Silver-coated fabric increases resistance to infection by S. epidermidis in this direct-contamination, mouse subdermal model.

How to cite: Illingworth, B., Bianco, R. W., & Weisberg, S. (2000). In vivo efficacy of silver-coated fabric against Staphylococcus epidermidis. The Journal of heart valve disease, 9(1), 135–141.

Background and aim of the study: The rate of recurrent postoperative endocarditis after valve replacement in early-stage acute infective endocarditis is extremely high. Metallic silver coating of the sewing ring may improve the short- and long-term outcome after valve implantation. This report details our experience with the St. Jude Medical Silzone prosthesis in early surgical treatment of acute infective endocarditis.

Methods: Ten patients (mean age 66.4 years) referred for native valve or prosthetic valve endocarditis were operated on between April 1998 and June 1999. The microorganisms responsible for the acute infection were Staphylococcus (n = 1), Streptococcus (n = 1) and Pseudomonas aeruginosa (n = 1); blood cultures remained negative in two cases. The indication for surgical treatment was related to hemodynamic condition (n = 5), a major cerebral event (stroke; n = 1), annulus abscess (n = 1), and echocardiographic evidence of large cuspal vegetations (n = 3). All patients had received preoperative intravenous antibiotics (mean 7.8 days). Four mitral, five aortic valve replacements, and one double mitral-aortic valve replacement, were performed after extensive debridement of the infected and necrotic tissues. Mean duration of postoperative antibiotic treatment was 32.3 days. Postoperative follow up (mean 6 months; range: 2-14.2 months) was 100% complete, and included prospective repeated transthoracic echocardiography at one week, and one, six and 12 months postoperatively.

Results: One patient died early in the immediate postoperative period from pneumonia and major hypoxemia. All other patients are symptom-free, without evidence of recurrent infection and perivalvular leak.

Conclusion: Although these early results with the St. Jude Medical Silzone prosthesis require confirmation by more extensive studies, they infer that silver coating of the sewing ring may dramatically improve management of patients with active endocarditis.

How to cite: Bertrand, S., Houel, R., Vermes, E., Soustelle, C., Hillion, M. L., & Loisance, D. (2000). Preliminary experience with Silzone-coated St. Jude medical valves in acute infective endocarditis. The Journal of heart valve disease, 9(1), 131–134.

How to cite: Brutel de la Riviere, A., Dossche, K. M., Birnbaum, D. E., & Hacker, R. (2000). First clinical experience with a mechanical valve with silver coating. The Journal of heart valve disease, 9(1), 123–130.

Background and aim of the study: Pericardial valves combine optimal hemodynamic properties with limited durability. To describe the long-term performance of Mitroflow pericardial valves in the aortic position, outcome and risk factors up to 12 years after implantation were analyzed.

Methods: A retrospective study, based on follow up of 1,029 patients who received 1,044 Mitroflow pericardial valves in the aortic position between February 1985 and December 1996, was performed. Follow up was 98.2% complete. Average follow up was 3.79 years. Mean patient age was 75.2+/-6.5 years (range: 27.9-90.9 years). At surgery, 86.3% of patients were aged over 70 years. Among patients, 482 (46.8%) had concomitant operations.

Results: Results (+/- SE) are given for evident and possible (in parentheses) valve-related events; the latter included all reported postoperative strokes and sudden deaths. Actuarial event-free rates after 5 and 10 years respectively were: structural valve deterioration: 99.2+/-0.5% and 77.6+/-4.4%; non-structural valve deterioration: 99.7+/-0.2% and 99.7+/-1.2%; valve-related complications: 95.7+/-0.9% and 73.5+/-4.0% (5 years 90.1+/-1.2%, 10 years 57.0+/-4.3%); endocarditis: 96.6+/-0.8% and 92.6+/-1.6%; explantation: 98.6+/-0.5% and 80.1+/-3.9%; cerebrovascular accident 95.2+/-0.9% and 82.5+/-3.5%; embolism 99.9+/-0.1% and 99.9+/-0.5%; bleeding 99.8+/-0.2% and 99.8+/-1.3%; overall mortality 69.9+/-1.8% and 35.3+/-3.0%; valve-related death 97.5 +/-1.1% and 95.1+/-4.2% (5 years 91.9+/-1.4%, 10 years 76.1+/-3.2%). The 30-day mortality rate was 4.1%. Patients aged 70 years or more with valve diameters of < or =23 mm showed 10-year freedom rates of 85.8+/-4.6% for structural valve degeneration and 95.1+/-1.2% for evident valve-related death. The detailed risk factor analysis showed results that were in accordance with clinical experience.

Conclusion: Long-term results with Mitroflow pericardial valves in the aortic position compare well with those for other widely used bioprostheses, especially in patients aged > or =70 years and with small aortic root diameters (< or =23 mm).

How to cite: Minami, K., Boethig, D., Mirow, N., Kleikamp, G., Koertke, H., Godehardt, E., & Koerfer, R. (2000). Mitroflow pericardial valve prosthesis in the aortic position: an analysis of long-term outcome and prognostic factors. The Journal of heart valve disease, 9(1), 112–122.

Background and aim of the study: This study was performed to elucidate the mechanism of primary tissue failure of bioprosthetic heart valves, which were fabricated from autologous pericardium (Autogenics). Results were compared with the degeneration pattern of heterologous pericardial bioprostheses.

Methods: Between March 1994 and December 1996, 87 Autogenics heart valves were implanted in the aortic position. Since then, 15 valves had to be explanted due to structural deterioration. The average implant period was 33+/-8 months. All explants were examined by gross morphological evaluation and X-ray analysis to identify the failure mode of these devices. In eight explanted autologous tissue valves and six explanted heterologous pericardial bioprostheses, exact morphological evaluation was performed by scanning electron microscopy, microscopic and immunohistochemical techniques.

Results: All autologous tissue valves failed due to cuspal tears localized at the commissures. Nocalcification could be detected by X-ray analysis and microscopic methods. Endothelial cell coverage was evident at the outflow surface of all autologous bioprostheses. Histological examination showed severe disintegration of the collagen fibers by insudated plasma proteins and erythrocytes, and the absence of the original fibroblasts. Collagen fibers were vigorously altered between the inner and outer stent of the Autogenics valve. In contrast, heterologous pericardial valves failed due to severe calcification of the cusps. Histological evaluation displayed invasion of macrophages and calcific deposits. The collagenous texture of the pericardial tissue was significantly better preserved compared with autologous tissue.

Conclusion: High biocompatibility of autologous tissue valves is indicated by the absence of calcium deposits, macrophages and foreign body giant cells, and the presence of endothelial cell ingrowth. Severe disintegration of autologous tissue suggests that brief immersion in glutaraldehyde generates inadequate mechanical stability of bioprosthetic heart valve material. Heterologous valves exhibit low biocompatibility but superior preservation of the collagenous biomaterial.

How to cite: Grabenwöger, M., Fitzal, F., Gross, C., Hutschala, D., Böck, P., Brucke, P., & Wolner, E. (2000). Different modes of degeneration in autologous and heterologous heart valve prostheses. The Journal of heart valve disease, 9(1), 104–111.

Background and aim of the study: Unstented aortic valve substitutes offer many of the theoretical advantages of homografts such as superior hemodynamic performance and enhanced durability, particularly when inserted as a root. Many of these depend on the maintained flexibility of the valve components. Calcification of the aortic wall may adversely affect these phenomena. Electron beam computed tomography has been used to evaluate aortic wall calcification in patients undergoing aortic root replacement in a prospective randomized trial designed to compare the Medtronic Freestyle valve with the homograft valve replacement.

Methods: Patients were followed with electron beam computed tomography scans of the aortic root at six-monthly intervals after surgery. A calcification score (Hounsfield units) and a calcified volume score (mm3) were obtained from each scan using a new modified technique. Results were related to hemodynamic data from echocardiography. The prevalence of calcification was also related to the homograft donor age.

Results: Seventy-six patients (age range: 40-79 years) were randomized to root replacement with either homograft (n = 31) or Freestyle (n = 45) valves. Fifty-three scans of the aortic root were performed postoperatively in 37 patients. No statistical difference between the two groups was found at six and 12 months after surgery. However, after 18 months the calcified volume score was 5903.8+/-2356.8 mm3 in the homograft versus 2725.6+/-1500.5 mm3 in the Freestyle group (p = 0.017). There was a correlation between calcification score, calcified volume score and left ventricular mass (r = 0.323, p = 0.093 and r = 0.350, p = 0.068, respectively) on the one hand, and calcification score, calcified volume score and valve size on the other hand (r = 0.178, p = 0.466 and r = 0.068, p = 0.780, respectively).

Conclusions: Electron beam computed tomography provides a powerful tool for the detection of calcium in the aortic wall of valve grafts. There is a low rate of calcification during the first 18 months in the Medtronic Freestyle valve, and this appears to be lower than that observed in homografts. Longer-term follow up of the aortic root in these patients is required. This is an ongoing study.

How to cite: Melina, G., Rubens, M. B., Birks, E. J., Bizzarri, F., Khaghani, A., & Yacoub, M. H. (2000). A quantitative study of calcium deposition in the aortic wall following Medtronic Freestyle compared with homograft aortic root replacement. A prospective randomized trial. The Journal of heart valve disease, 9(1), 97–103.

Background and aim of the study: Porcine, specially manufactured bioprosthetic valves regulate blood flow from the left ventricle to pump sac (inflow valve) and from the pump to the aorta (outflow valve) in a wearable, electrically powered left ventricular support system (LVAS, Novacor). The increased need for long-term circulatory assistance requires information on the evolution of these valves when exposed to specific hemodynamic conditions and inflammatory reactions in the device. The study aim was to examine structural changes in valves from explanted LVASs.

Methods: Thirteen patients (11 males, two females; mean age 42 years (range: 17-64 years) were supported for a mean of 285 days (range: 37-1,293 days) with LVAS. Histologic sections from explanted inflow and outflow valves were studied immunohistochemically using peroxidase-labeled antibodies and avidin-biotinylated peroxidase complex for detection.

Results: In the macroscopically normal inflow valves (11/13), the outflow surface (facing the pump) was covered with a discontinuous deposit of fibrin, macrophages and granulocyte elastase. Fibrinogen, IgG, complement proteins C1q and C3 had infiltrated the extracellular matrix (ECM) between 37 and 1,293 days. The crevices were enlarged during circulatory support, and fibrinogen/fibrin insudations were detected in the spongiosa. The collagen layers in the fibrosa were disrupted after 293 days, and eroded on the inflow surface in the ventricularis after 1,293 days. In a deteriorated valve from a patient with endocarditis, Gram-positive bacteria and metalloproteinases were concentrated in the ECM. In the macroscopically normal (11/13) outflow valves, fibrin and complement proteins had penetrated the ECM from the inflow side (facing the pump), while macrophages and granulocytes were localized mainly on the outflow surface. IgG and complement proteins were detected on and beneath the cusp surface up to 200 days and covered the disrupted ECM as implant time progressed.

Conclusions: Structural changes appear to progress more rapidly in the inflow than in the outflow of bioprosthetic valves. This difference indicates that the effects of biological factors are modulated by mechanical stress.

How to cite: Moczar, M., Houël, R., Ginat, M., Clérin, V., Wheeldon, D., & Loisance, D. (2000). Structural changes in porcine bioprosthetic valves of a left ventricular assist system in human patients. The Journal of heart valve disease, 9(1), 88–96.

Background and aim of the study: The rise of pressure in the pulmonary circulation during the course of mitral stenosis leads to pathomorphological changes and a reduction in vascular compliance. Endothelial dysfunction is also promoted, with increased expression of endothelin. This aim of this study was to evaluate whether the increase in endothelin-1 levels in pulmonary hypertension due to advanced mitral stenosis is reversible after valve replacement.

Methods: Thirty-nine patients with isolated, longlasting post-rheumatic mitral stenosis were enrolled. During preoperative Swan-Ganz catheterization blood samples were withdrawn from the pulmonary artery and capillaries for measurement of endothelin-1 (ET-1). Similar examinations were performed six months after mitral valve replacement. Hemodynamic parameters were measured also during 25-W exercise effort.

Results: The mean preoperative hemodynamic parameters of the pulmonary circulation were moderately increased. Mean plasma levels of ET-1 were about three-fold higher than normal. Capillary levels of ET-1 were significantly higher than those in the pulmonary artery (1.78+/-1.22 versus 1.03+/-1.16 pg/ml, p <0.05). There was no significant correlation between ET-1 level and any hemodynamic or clinical parameters, except NYHA functional class. After surgery, pulmonary capillary levels of ET-1 fell significantly, but were still high (1.78+/-1.22 versus 1.41+/-1.00 pg/ml); ET-1 levels in the pulmonary artery were unchanged. Patients with persistently high ET-1 levels had significantly worse exercise hemodynamic parameters, especially of pulmonary arterial compliance.

Conclusion: In patients with long-lasting, severe mitral stenosis, ET-1 levels remained increased and the ET-1 concentration gradient across the pulmonary circulation persisted for six months after valve replacement. High ET-1 capillary levels are correlated with poor exercise tolerance and poor exercise compliance of the pulmonary vessels.

How to cite: Snopek, G., Pogorzelska, H., & Korewicki, J. (2000). Influence of valve replacement on plasma endothelin-1 level in mitral stenosis. The Journal of heart valve disease, 9(1), 82–87.

Background and aim of the study: Repair of the prolapsing anterior leaflet (AML) in degenerative mitral valve disease is more demanding than that of the posterior leaflet. We reviewed our experience in the past eight years, to examine the safety, efficacy and stability of various repair artifices.

Methods: Between January 1989 and December 1997, 102 patients (mean age 64 years; range: 26-86 years) with mitral regurgitation (MR) due to prolapse of the anterior or both mitral leaflets underwent mitral valve repair. Sixty-six patients were in NYHA class > or =III, and 94 had MR grade >II. Acute endocarditis was present in 12 patients and Barlow disease in 16. Surgical techniques consisted of chordal shortening (n = 36), chordal transposition (n = 16), papillary muscle shortening or plication (n = 10), flip-over (n = 20) and artificial chordae implantation (n = 20).

Results: There was no early mortality; one patient required early mitral valve replacement (MVR) for late-appearing systolic anterior motion, and one patient benefited from a successful re-repair on day 8 for partial posterior leaflet desinsertion. Mean follow up was 30 months (range: 3-92 months); there were four late deaths (two valve-related cerebrovascular accidents); two patients required re-repair (one after three months for prosthetic ring thrombosis, and one after 10 months for rupture of shortened chordae (corrected by flip-over)). Five patients had MVR between four and 32 months later: one for mitral stenosis due to posterior leaflet calcification, and four for recurrent MR due to the rupture of shortened chordae (n = 3) or plicated papillary muscle (n = 1). One patient suffered bacterial endocarditis which was treated medically. Of the 92 remaining patients with valve repair, 81 are currently asymptomatic, five are in NYHA class II and four in class III. Transesophageal echocardiographic restudy (n = 76) at a mean of 30 months after surgery revealed no MR in 68 patients, and MR of grade <II in three.

Conclusions: AML prolapse repair is safe, durable, and therefore can be attempted even in mildly symptomatic patients. However, chordal shortening should be substituted by implantation of artificial chordae or by the flip-over technique.

How to cite:El Khoury, G., Noirhomme, P., Verhelst, R., Rubay, J., & Dion, R. (2000). Surgical repair of the prolapsing anterior leaflet in degenerative mitral valve disease. The Journal of heart valve disease, 9(1), 75–81.

Background and aim of the study: The management of concomitant moderate or severe ischemic mitral regurgitation in the presence of ischemic heart disease is important for long-term prognosis. Mitral repair by either a suture or ring annuloplasty method has been advocated, although clear superiority of either method has not been established.

Methods: Combined coronary artery bypass and mitral valve surgery for ischemic mitral incompetence was performed on 68 consecutive patients between January 1996 and December 1998. The outcome in 63 of these patients (35 females, 28 males) who underwent mitral valve repair was reviewed.

Results: Average patient age was 61+/-9.4 years (range: 39-81 years). Average left ventricular ejection fraction (LVEF) was 42.1%; a suture annuloplasty was used in 84% and a ring in 16%. The average number of distal anastomoses was 3.9+/-1.1 (range: 1-6) and aortic cross-clamp time was 131+/-35 min (range: 58-238 min). Operative mortality rate (<30 days or in-hospital) was 12.7% and only requirement for intra-aortic balloon pumping either before or during surgery (21%) was predictive (p<0.05). On discharge, 98.2% of patients were in NYHA class I or II. Follow up (range: 1-35 months) was complete in 95% of cases. Moderate mitral regurgitation on discharge occurred in nine patients and was not related to the type of annuloplasty. Predictive risk factors were preoperative severe mitral regurgitation (p<0.04), poor LVEF (p = 0.05), and was predictive of deterioration of NYHA class (p<0.02), progression of regurgitation (p<0.05), and poor outcome (p<0.01). Poor outcome was also related to surgeon's experience. Structural valvular deterioration occurred in 21.8% of operative survivors, and there was one reoperation and four late deaths. The survival rate (including operative deaths) at 35 months was 68.3 +/- 13.1%, and event-free survival rate (no mortality, reoperation or angina) 65.2+/-6.2%.

Conclusions: The type of annuloplasty used did not influence outcome. The risk of structural mitral valve dysfunction on follow up was related to severe preoperative mitral regurgitation, poor LVEF, surgeon's experience, and was predictive of poor outcome.

How to cite: von Oppell, U. O., Stemmet, F., Brink, J., Commerford, P. J., & Heijke, S. A. (2000). Ischemic mitral valve repair surgery. The Journal of heart valve disease, 9(1), 64–74.

Background and aims of the study: Limited information is available on the healing of wounds in the mitral valve. In the present study, this process has been evaluated in young sheep.

Methods: Histologic, histochemical and transmission electron microscopic studies were made of the healing of wounds produced surgically under cardiopulmonary bypass, in the mitral valve (a 1 cm-long radially oriented incision at the free edge of the anterior leaflet) of young sheep (n = 11).

Results: All animals developed severe mitral regurgitation, as demonstrated by hemodynamic, ultrasound and ventriculographic studies. At four to five weeks, the edges of the incision were only partially covered by endothelium and had small deposits of fibrin. Two types of granulation tissue were associated with wound healing. The first covered the cut edge and consisted of myxoid tissue that extended from the valvular spongiosa and fibrosa; the second type consisted of spindle-shaped cells arranged parallel to the surface and surrounded by a slightly myxoid stroma. This granulation tissue resembled that caused by reactive fibrosis in regurgitant mitral valves. The connective tissue cells in granulation tissue developed increasing amounts of actin-like filaments as a function of time after operation. This differentiation resulted in the development of myofibroblasts. In contrast to the avascular nature of normal mitral leaflets, capillaries and arterioles first appeared in the middle portion of the leaflet at eight weeks, and at the proximal edges of the wounds at 12 weeks.

Conclusion: The healing of mitral valvular wounds is a slow process that requires between eight and 12 weeks for the formation of a dense collagenous scar at the edges and complete restoration of the endothelial lining. Progression of healing is associated with the phenotypic modulation of connective tissue cells from fibroblasts to myofibroblasts and neovascularization of the leaflets.

How to cite: Tamura, K., Jones, M., Yamada, I., & Ferrans, V. J. (2000). Wound healing in the mitral valve. The Journal of heart valve disease, 9(1), 53–63.

Background and aim of the study: The study aim was to examine comparatively the effects of prosthetic and homograft valves in the aortic position on ventricular hemodynamics and structure.

Methods: Hemodynamic evaluations were performed at rest and during exercise in 38 patients who had undergone aortic valve replacement (AVR) with either a homograft (n = 19) or prosthetic valve (19-23 mm; n = 19). Using echocardiographic, electrocardiographic and hematologic methods, the pressure gradient (PG); aortic valve area; diameters of left anterior wall, posterior wall (PW) and interventricular septum (IVS); ejection fraction (EF); left ventricular mass (LVM) and mass index (LVMI); electrocardiographic data of LV hypertrophy; hemoglobin; hematocrit and lactate dehydrogenase (LDH) levels were measured.

Results: LVM and LVMI decreased significantly after surgery in both groups (p<0.001), but the decrease was significantly greater in the homograft group (p<0.05). The IVS and PW diameters in the homograft group decreased significantly postoperatively (p<0.05); the inter-group difference was also significant (p<0.01). In the homograft group there was a significant improvement in EF (p<0.05), and the exercise PG was significantly less. Both groups showed improved LV hypertrophy and correlation between V1S >24 mm criteria and LVMI measurements. Postoperative LDH levels in the homograft group were significantly lower than preoperative levels (p<0.05); the intergroup difference was also significant (p<0.001).

Conclusions: Our data suggest that homografts, as compared to mechanical prostheses, provide significantly better hemodynamics in the aortic position.

How to cite: Basarir, S., Islamoglu, F., Ozkisacik, E., Atay, Y., Boga, M., Bakalim, T., Ozbaran, M., & Telli, A. (2000). Comparative analysis of left ventricular hemodynamics and hypertrophy after aortic valve replacement with homografts or mechanical valves. The Journal of heart valve disease, 9(1), 45–52.

Background and aim of the study: A total of 213 patients underwent the Ross operation at our institution between January 1990 and January 1999. Outcome was assessed in rheumatic (RH) patients and compared with that in patients with other etiology (non-RH).

Methods: After exclusion of 69 patients with a follow up of <18 months, the study group comprised 144 patients (119 RH, 25 non-RH). Patients were studied clinically and by echo-Doppler cardiography preoperatively, within 2 months and 6-8 months after surgery, and yearly afterwards. Preoperative assessment included age, gender, body surface area (BSA), type of aortic valve lesion and additional valve disease, left and right ventricular outflow tract (LVOT, RVOT) dimensions, and left ventricular (LV) size, function and mass. Postoperatively, patients were studied for presence and severity of autograft regurgitation, mitral regurgitation, LV size, function and mass, and incidence and timing of reoperation.

Results: On average, RH patients were older and had higher BSA, more aortic regurgitation than stenosis, more additional mitral valve disease (mostly regurgitation), larger LV size and poorer LV function. Mitral valve repair was performed in 24% of RH patients versus 0% of non-RH patients. Postoperatively, differences in LV size, function and mass remained present, but diminished during follow up. The autograft reoperation incidence was 22% (26/119) in RH patients versus 8% (2/25) in non-RH patients (p = NS). Preoperative predictors for reoperation in the RH group were severe concomitant mitral regurgitation (MR), followed by male gender and large indexed LVOT (all p<0.001 by discriminant analysis).

Conclusion: Marked differences were present in patient characteristics between rheumatic and nonrheumatic patients who underwent the Ross operation. Rheumatic patients had a higher incidence of autograft reoperation. Severe concomitant MR was the most important predictor for reoperation in rheumatic patients.

How to cite: Pieters, F. A., Al-Halees, Z., Hatle, L., Shahid, M. S., & Al-Amri, M. (2000). Results of the Ross operation in rheumatic versus non-rheumatic aortic valve disease. The Journal of heart valve disease, 9(1), 38–44.

Background and aim of the study: The surgical placement of pulmonary valve grafts into the aortic position (the Ross procedure) has been performed for three decades. Cryopreserved pulmonary valves have had mixed clinical results, however. The objectives of this study were to compare the mechanics of cryopreserved human aortic and pulmonary valve cusps and roots to determine if the pulmonary root can withstand the greater pressures of the aortic position.

Methods: Six aortic and six pulmonary valve roots were obtained from the Oxford Valve Bank. They were harvested during cardiac transplantation from hearts explanted for dilated cardiomyopathy (mean patient age 68 years). The whole roots were initially stored frozen at -186 degrees C, then shipped packed on dry ice. After complete thawing, the roots were pressurized whole; test strips were then cut from the valve cusps, roots and sinuses and tested for stress/strain, stress relaxation, and ultimate failure strength.

Results: The pulmonary roots were more distensible (30% versus 20% strain to lock-up) and less compliant when loaded to aortic pressures. The pulmonary valve cusp and root tissue also showed greater extensibility and greater stiffness (lower compliance) when subjected to the same loads.

Conclusion: We conclude that mechanical differences between aortic and pulmonary valve tissues are minimal. The pulmonary root should withstand the forces imposed on it when placed in the aortic position. However, if implanted whole, the pulmonary root will distend about 30% more than the aortic root when subjected to aortic pressures. These geometric changes may affect valve function in the long term and should be appreciated when implanting a pulmonary valve graft.

How to cite: Vesely, I., Casarotto, D. C., & Gerosa, G. (2000). Mechanics of cryopreserved aortic and pulmonary homografts. The Journal of heart valve disease, 9(1), 27–37.

Background and aim of the study: The excellent results with atrioventricular valve reconstruction have stimulated surgeons to attempt reconstruction of calcified aortic valves using decalcifying techniques, but long-term results have been disappointing. The aim of this in vitro study was to evaluate the surface structure of decalcified aortic valve tissue and its potential for recalcification.

Methods: Aortic leaflets were removed from 26 patients with aortic stenosis during elective valve replacement and decalcified by meticulous dissection. Representative specimens were prepared for scanning electron microscopy (SEM) and calcium content in the heavily calcified part of the leaflet in both macroscopically non-calcified and decalcified tissue was determined by atomic absorption spectroscopy (AAS). Additional probes of 'non-calcified' and decalcified tissue were incubated for two and four weeks with medium containing a physiological concentration of calcium to determine their potential for recalcification. As a control, 13 specimens from non-calcified valves were incubated according to the same protocol.

Results: All calcified specimens contained high calcium levels (142.70+/-53.76 mg/g). Surgical dissection reduced tissue calcium content significantly (10.04+/-13.43 mg/g). Following two weeks' incubation with calcium, these specimens retained significantly higher levels of calcium (2.88+/-5.17 mg/g) than the 'non-calcified' specimens (19.17+/-7.61 versus 13.49+/-6.27 mg/g; p<0.05); after four weeks similar calcium levels were reached (32.00+/-10.27 versus 28.35+/-9.84 mg/g; p = NS). Non-calcified tissue showed the lowest calcium uptake (4.75+/-4.55 mg/g and 12.29+/-9.43 mg/g at two and four weeks; p<0.05). SEM revealed a loss of endothelial coverage in the calcified areas; decalcification led to an irregular fibrillar surface. Only parts of the macroscopically normal tissue contained endothelial cells, whereas the control tissue showed intact cellular coverage.

Conclusion: Aortic valve decalcification can effectively remove calcifications, but leaves a fibrillar structure that tends rapidly to accumulate calcium. Even normal-appearing tissue from diseased valves has a higher potential for calcification than normal valvular tissue. These data support the observation of only limited clinical benefits being derived after aortic valve decalcification for aortic stenosis.

How to cite: Dahm, M., Dohmen, G., Groh, E., Krummenauer, F., Hafner, G., Mayer, E., Hake, U., & Oelert, H. (2000). Decalcification of the aortic valve does not prevent early recalcification. The Journal of heart valve disease, 9(1), 21–26.

Background and aim of study: During the June 1999 World Symposium on Heart Valve Disease, the mechanism by which the aortic valve opens was discussed. It was suggested, indirectly, that the recently discovered contractile elements within the aortic valve may be responsible. We propose that aortic root dilation does not require any active mechanism within the leaflets or aortic wall, and provide an explanation based entirely on the passive hemodynamics of the aortic valve and root.

Methods and results: Previous studies using cine fluoroscopy and sonomicrometry have reported a 5-7% expansion of the aortic root during ventricular contraction, prior to aortic valve opening. Simplified force calculations indicate that the mechanical interactions between the aortic valve and root produce an inward pull on the commissures, constraining the aorta from fully dilating. During systole, as the pressure in the ventricle increases and the aortic valve becomes unloaded, the inward pull on the commissures is reduced and the aorta is able to dilate fully. Aortic dilation therefore occurs before the aortic valve opens.

Conclusion: We conclude that this mechanism of aortic root dilation prior to valve opening is purely passive, and does not require any active process by the aortic valve or the aortic root.

How to cite: Vesely I. (2000). Aortic root dilation prior to valve opening explained by passive hemodynamics. The Journal of heart valve disease, 9(1), 16–20.

Background and aim of the study: The increased use of autologous, homologous or heterologous aortic root demands a detailed knowledge of its anatomy and function. The advent of 3-D digital sonomicrometry offered the opportunity to acquire precise information on the root and leaflet movements during the cardiac cycle.

Methods: Under cardiopulmonary bypass, sonomicrometry crystals were implanted in the aortic root and valve of eight sheep. Crystals were sutured at each commissure (n = 3), the top of the sinotubular junction (n = 3), lowest point of the annulus (n = 3), and leaflet tip (n = 3). 3-D coordinates of each crystal were recorded, together with left ventricular and aortic root pressures and ECG. When the animal had returned to a stable hemodynamic condition, the maximum and minimum distances between two crystals, and areas between three crystals, were calculated. Changes in root volume and leaflet position were time-related to the pressure changes.

Results: The most significant change between maximum and minimum distance between crystals during the cardiac cycle occurred at the commissural level. Similarly, the triangle defined by the three commissural crystals showed the greatest change in area (47%). The root volume increased by an average of 22%; about 40% of this increase occurred during the isovolumic phase. The aortic leaflets began to open before ejection.

Conclusion: We postulate that aortic valve opening is initiated by the outward pull of the commissures. These findings should impact on aortic root surgery.

How to cite: Pang, D. C., Choo, S. J., Luo, H. H., Shomura, Y. U., Daniel, S., Nikolic, S., Cheung, D. T., Oury, J. H., & Duran, C. M. (2000). Significant increase of aortic root volume and commissural area occurs prior to aortic valve opening. The Journal of heart valve disease, 9(1), 9–15.

Background and aim of the study: Normal valves are known to be metabolically active, yet the route of oxygen delivery is unclear. Although diffusion from the valve surface is the presumed source, the presence, distribution and importance of the aortic valve's vascular bed is unclear.

Methods: Seventeen porcine hearts (51 cusps) were obtained at slaughter. The coronary circulation was pressure-rinsed with a heparin solution and filled with an Aquablack solution at physiological pressure. The cusps were subsequently dissected and fixed for viewing with an inverted microscope. The anterior leaflet of the mitral valve was evaluated as a control for the vessel filling protocol. Using Adobe Photoshop and captured images, whole cusps were reconstructed, a grid was overlaid and vascular distribution evaluated.

Results: Of the 15 porcine aortic valves that filled, 32/45 (71%) of the cusps contained vessels. Nine valves had vasculature in all three cusps and two valves were completely avascular. Vessels were found predominantly in the basal third of the cusps and extended in from the commissures almost to the level of the free edge. There was a statistically significant difference (p<0.001) between the appearance of vessels in the basal region and in the mid and free edge regions of the valve. No difference in vascularization pattern was noted between the left, right or non-coronary cusps.

Conclusions: The presence of a vasculature suggests that the metabolic activity of the cusp is greater than can be supported by diffusion from the cusp surface alone. The absence of functioning vessels might explain the failure associated with cryopreserved implants and may play a role in the durability problems faced by bioprosthetic valves. It will also be important to consider the role of this intrinsic circulation with the advent of tissue-engineered valves.

How to cite: Weind, K. L., Ellis, C. G., & Boughner, D. R. (2000). The aortic valve blood supply. The Journal of heart valve disease, 9(1), 1–8.