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How to cite: McKeown, A. J., & Cameron, E. (1996). Reoperative mitral valve surgery via right thoracotomy: decreased blood loss and improved hemodynamics. The Journal of heart valve disease, 5(4), 463.

Background and aims of the study: The choice of prosthesis becomes crucial in the narrow aortic annulus. The 20 mm Medtronic Hall valve has a reduced sewing ring that fits in an annulus where only a 19 mm valve would fit. This study assesses the hemodynamic performance of this prosthesis at rest and at exercise, and compares it with two 19 mm mechanical prostheses.

Materials and methods: Forty-two patients were studied by Doppler echocardiography, a mean of 34 months following surgery. Twenty-six had a 19 mm prosthesis implanted (12 standard St. Jude Medical and 14 Monostrut valves) and 16 had a 20 mm Medtronic Hall. Parameters studied were peak velocity and transvalvular gradient, both at rest and at exercise, effective orifice area and valve index.

Results: No differences were found between the two 19 mm valves, but when compared with the Medtronic Hall valve at rest, this valve showed significantly lower peak velocity and gradient (2.9 vs. 3.3 m/sec, p < 0.01, and 17 vs. 23 mmHg, p < 0.003, respectively) and higher effective orifice area and valve index (1.3 vs. 1.0 cm2, p < 0.01 and 0.81 vs. 0.62 cm2, p < 0.006, respectively). There were also significant differences under exercise.

Conclusions: The 20 mm Medtronic Hall prosthesis shows a significantly better hemodynamic performance, both at rest and under exercise, than other, 19 mm mechanical prostheses and represents a superior choice in valve replacement with a small aortic root.

How to cite: Aris, A., Ramirez, I., Camara, M. L., Carreras, F., Borras, X., & Pons-Llado, G. (1996). The 20 mm Medtronic Hall prosthesis in the small aortic root. The Journal of heart valve disease, 5(4), 459–462.

Background and aims of the study: The high prevalence of rheumatic valvular disease in the young population and the high cost of imports necessitated the development of an Indian valve. The development of a tilting disc prosthesis was successfully concluded in February 1995, when the third model completed its clinical trial. The tilting disc valve has an integrally machined cobalt alloy cage, an ultra high molecular weight polyethylene disc and a polyester suture ring. The choice of design was based on its superior hydrodynamics and the age distribution of patients, the majority of whom were below 30 years. The polymer-metal combination was selected for its extremely low wear rate and proven durability in the human body.

Materials and methods: The hydrodynamic performance was tested under steady and pulsatile flow conditions. The accelerated durability of nine test valves was evaluated at 800-840 cycles/min for over 350 million cycles each. Size 23 mm valves mere implanted in the mitral position of five sheep. In a clinical trial, 306 patients with isolated mitral or aortic valve replacements were followed up for a total of 371 patient years (mean 1.37 years and range 0-4 years).

Results: The hydrodynamic performance was comparable to that of proven clinical models. The accelerated testing indicated lifetimes in excess of 50 years and the animal trials showed the valve to be safe. In the clinical trial, there was no incidence of structural failure or paravalvular leak. The linearized rate of late thromboembolism was 6.2%/patient-year (pty), anticoagulant related hemorrhage 0.54%/pty and infective endocarditis 0.54%/pty. At two years, the total actuarial survival was 89.5%. The higher incidence of thromboembolism and the very low incidence of anticoagulant related hemorrhage illustrate the difficulty in the management of anticoagulant therapy in a developing country, while the low incidence of endocarditis reflects their greater resistance to infection.

Conclusion: These data clearly showed the valve to be safe and comparable to other similar valves in clinical use.

How to cite: Bhuvaneshwar, G. S., Muraleedharan, C. V., Vijayan, G. A., Kumar, R. S., & Valiathan, M. S. (1996). Development of the Chitra tilting disc heart valve prosthesis. The Journal of heart valve disease, 5(4), 448–458.

Background and aims of the study: Limited durability of porcine bioprostheses is mainly caused by the progressive development of calcification. We tested the hypothesis that hidden tissue anomalies or unfavorable stress concentrations of commercially available bioprostheses may lead to later calcification and dysfunction. Application of holographic interferometry for non-destructive testing of biological heart valves enables a full-field analysis of heart valves and reveals deformation irregularities of valve tissue.

Material and methods: We developed an accelerated calcification protocol for bioprosthetic heart valves including an accelerated pulsatile valve tester for simultaneous testing of 10 heart valves under identical conditions and a rapid synthetic calcification fluid containing a final Ca x P of 130 (mg/dl)2 in barbital buffer solution. Ten porcine bioprostheses (St. Jude Medical, Bioimplant) were assessed by holographic interferometry and subjected to the pulsatile accelerated calcification process. Distribution and amount of calcification was evaluated by microradiography after 12 x 10(6) and 19 x 10(6) cycles, respectively. Areas of irregular fringe patterns detected by holography as well as areas of calcification were calculated and compared using a personal computer.

Results: All tested bioprostheses had localized or extended areas with holographic irregularities and the accelerated valve testing protocol resulted in even macroscopically visible calcifications at various sites. Comparative analysis of the obtained microradiographs revealed that 74.2% +/- 6.0% of calcified leaflet areas lay within the previously detected holographic anomalies.

Conclusions: Our first results show a strong correlation between holographic anomalies and calcification of porcine bioprostheses. We conclude that suitable methods for evaluation and quality control of bioprosthetic heart valves are available and seem to be predictive with regard to valve calcification.

How to cite: Deiwick, M., Glasmacher, B., Zarubin, A. M., Reul, H., Geiger, A., von Bally, G., Stargardt, A., Rau, G., & Scheld, H. H. (1996). Quality control of bioprosthetic heart valves by means of holographic interferometry. The Journal of heart valve disease, 5(4), 441–440.

Background and aims of the study: Percutaneous mitral valvulotomy has been shown to be an accept able alternative to surgery as treatment for selected patients with severe mitral stenosis. Uncertainty still exists regarding predictors of unsuccessful outcome.

Materials and methods: 308 patients with severe mitral stenosis underwent Inoue single balloon valvulotomy over a 48-month period and were followed up for a mean of 14.5 +/- 16.8 months (range one to 64 months). Two hundred and sixty-seven (Group I) improved clinically and remained stable throughout the follow up, while subsequent surgery was required in 41 (Group II) after 38.2 +/- 143.5 days (range one to 1,212). Clinical and echocardiographic parameters of the two groups were compared to find significant predictors of an unsuccessful outcome.

Results: Significant differences between the groups were observed for NYHA class (2.7 +/- 0.6 vs. 2.9 +/- 0.6, p < 0.05), mitral valve area (1.0 +/- 0.3 vs. 0.9 +/- 0.2 cm2, p < 0.01), left atrial end-systolic dimension by echo (51.3 +/- 8.0 vs. 55.4 +/- 10.2 mm, p < 0.01) and an echocardiographic scoring system including grading for eccentricity of the mitral orifice and distribution of commissural calcification (7.5 +/- 2.0 for Group I and 8.7 +/- 2.0 for Group II, p < 0.001).

Conclusions: Mitral valves that are more likely to have an unsuccessful outcome can be identified by hemodynamic, clinical and echocardiographic criteria, including grading for eccentricity of the mitral orifice and distribution of commissural calcification.

How to cite: Miche, E., Bogunovic, N., Fassbender, D., Baller, D., Gleichmann, U., Mannebach, H., Terwesten, H. P., Schmidt, H., Minami, K., Mirow, N., Vogt, J., & Körfer, R. (1996). Predictors of unsuccessful outcome after percutaneous mitral valvulotomy including a new echocardiographic scoring system. The Journal of heart valve disease, 5(4), 430–435.

Background and aims of the study: The purpose of this study is to analyze treatment options for valvular regurgitation with severe left ventricular dysfunction.

Material and methods: Results of valvular surgery in 98 patients with mitral or aortic regurgitation and severe systolic left ventricular dysfunction (LVD) were analyzed. Selection criteria were the absence of significant coronary heart disease and a resting ejection fraction (EF) < 40% for aortic and < 50% for mitral regurgitation.

Results: In patients with aortic regurgitation (n = 46) operative mortality was higher but not significantly so than in a control group of 238 cases (6.5% vs. 3.4%). The actuarial survival rates at five and 10 years were 84% and 55% vs. 84% and 67%, respectively. Independent preoperative predictors of severe postoperative LVD were rheumatic etiology and increased left ventricular end-systolic diameter. In patients with mitral regurgitation (n = 52), operative mortality was not significantly different from that of a control group of 273 cases (3.8% vs. 2.6%), whether the surgical procedure was valve replacement or valve repair. Perioperative morbidity was frequent (30% of cases), mainly low cardiac output, after valve replacement. The actuarial survival rates at eight years were respectively for the groups with and without LVD: 81% and 89% after valve repair, 60% and 75% after valve replacement. Independent predictors of severe postoperative LVD were increased left ventricular end-systolic volume and the type of surgery. Better results were observed after valve repair.

Conclusions: It is concluded that a low EF is not a predictive factor of operative mortality but it influences late survival as do the degree of left ventricular dilatation, etiology in aortic and type of surgery in mitral regurgitation. Alternatives to valvular surgery have been envisaged but information on vasodilators in these patients is scant and results of heart transplantation are known only from a few small series.

How to cite: Acar, J., Michel, P. L., Luxereau, P., Abou Jaoude, S., Cazaux, P., Dorent, R., Cormier, B., Jung, B., & Vahanian, A. (1996). How to manage patients with severe left ventricular dysfunction and valvular regurgitation. The Journal of heart valve disease, 5(4), 421–429.

A case of a false aneurysm arising at the proximal suture of an aortic root replacement with a pulmonary autograft is presented. This complication did not occur in the first postoperative month but was discovered late, and the female eight-year-old patient was in an extremely serious condition. She was reoperated on an emergency basis but died of acute pulmonary artery hypertension. The mechanism of the occurrence of such a case is discussed. In the absence of infection, structural weakness of the right ventricular muscle with progressive tearing is suggested. Strict and prolonged echocardiographic surveillance after the Ross procedure and early reoperation are mandatory.

How to cite: Metras, D., Kreitmann, B., Habib, G., Riberi, A., Yao, J. G., & Ross, D. N. (1996). False aneurysm: a rare and potentially severe complication after pulmonary autograft operation. The Journal of heart valve disease, 5(4), 414–417.

Background and aims of the study: Between January 1990 and July 1995, 108 patients underwent the Ross operation at our hospital. Most patients (90%) had severe aortic regurgitation (AR) in the setting of rheumatic heart disease. Although there have been no perioperative or late cardiac deaths, 12 patients (11%) developed severe AR requiring reoperation.

Material and methods: We performed an extensive and mostly retrospective analysis of echocardiographic data on all patients. Preoperative data were analyzed for age, sex, body surface area (BSA), size and comparison of the left and right ventricular outflow tracts (LVOT, RVOT), left ventricular (LV) size and function, and the presence of pulmonary regurgitation (PR) and concomitant mitral regurgitation (MR). Follow up data were analyzed for the presence, time of onset, evolution and severity of AR, characteristics of the AR jet, anatomic and functional aspects of the aortic root and valve, and evolution of LVOT diameter and LV size and function.

Results: Patients with autograft failure were younger with smaller BSA, larger indexed size of LVOT, RVOT and LV, and significantly more had concomitant severe MR. Postoperatively they had larger and increasing LVOT size. Trivial or mild AR was common and seen in almost all patients, as was a minimal degree of preoperative PR. Severe AR developed mostly after the first year of follow up, and reoperation was performed within three years in 11/12 patients. In nine patients cusp dilatation and prolapse (most frequently of the posterior cusp) was the cause of the AR, and rheumatic activity in three. Reoperation was not associated with mortality.

Conclusion: In our population autograft failure seems to be related to age, BSA and (indexed) LVOT, RVOT and LV size, but only the presence of significant concomitant mitral regurgitation before surgery was identified as a predictor for reoperation. Prolapse of one or more cusps were the cause of the AR in most patients. The graft is sensitive for recurrent rheumatic activity.

How to cite: Pieters, F. A., al-Halees, Z., Zwaan, F. E., & Hatle, L. (1996). Autograft failure after the Ross operation in a rheumatic population: pre- and postoperative echocardiographic observations. The Journal of heart valve disease, 5(4), 404–409.

Now that the Ross procedure (RP) has been established as the best method of aortic valve replacement (AVR) in several cohorts of patients, it is appropriate to analyze the evolution, as well as the anatomic and physiologic bases for it. Reviewing the evolution of this operation, one may understand the time lapse between its inception and the universal performance of this procedure. Experimental work began as early as 1927 by Hochrein. He was followed by the Stanford group, Lower in 1960 and 1961, and Pillsbury and Shumway in 1966. Successful clinical application by Donald Ross in 14 patients, two in the mitral and 12 in the aortic positions, was accomplished in 1967. Several important developments followed, including Marcel Geens' study of the blood supply to the ventricular septum in 1971 together with the improvement in surgical results following the initial experience of Gonzalez-Lavin and Ross. Further developments included assessment of the tensile strength of the pulmonary valve (PV) by Gorczynski (1982), ability to grow by Murata (1984), a finding of low Ca++ content of the PV by Livi in 1987 and of excellent hydraulic function by Wareesena in 1994. Finally there was universal acceptance by Elkins, Duran, and others, culminating with the Ross Registry and the establishment of the Ross Colloquium by Oury et al. A review of the anatomical features of the PV are compared with those of the aortic valve (AV), including gross anatomy and relationship to the sinotubular junction, scan microscopy and anisotropic properties of both AV and PV. The blood supply to the ventricular septum will be outlined by reviewing Marcel Geens work. The hemodynamics as reported by several investigators are reviewed. The clinical evidence of growth by Elkins et al. is outlined. Based on this increasing knowledge, indications and contraindications for AVR by the RP are discussed.

How to cite: Gonzalez-Lavin, L., Metras, D., & Ross, D. N. (1996). Anatomic and physiologic bases for the Ross procedure. The Journal of heart valve disease, 5(4), 383–403.

Background and aims of the study: The conventional isovolumic preparation with a single balloon, although employed for many years, distorts the chordae tendineae of the intact mitral apparatus.

Material and methods: Anterior balloon (one balloon inserted via a slit in the anterior leaflet) and double balloon (two balloons through slits in both leaflets) methods were developed and compared to the conventional method and natural conditions (LV filled with saline, or 'gold standard') in six ex-vivo, non-beating porcine hearts.

Results: LV volumes measured by the double balloon, anterior balloon, and conventional techniques all correlated highly with natural conditions, but the conventional method had a lower correlation coefficient (r = 0.99, 0.98, p < 0.0001 and < 0.001; and 0.92 p < 0.01, respectively at a left ventricular (LV) pressure of 50 mmHg, while r = 1.00, 1.00, both p < 0.0001; and 0.92, p < 0.01, respectively at 70 mmHg). Epicardial echocardiography revealed that the double balloon technique filled the space behind the chordae while maintaining normal chordal geometry, but the anterior balloon alone did not (p < 0.001). Similarly, the conventional method did not fill the LV outflow tract (p < 0.001) and had a mitral annular shift toward the left atrium (p < 0.001). Photography of both leaflets showed that only the double balloon method maintained normal geometry as assessed by leaflet length ratio; the other methods produced distorted geometry compared to natural filling conditions.

Conclusions: With an intact mitral valve, the double balloon method provides more precise LV pressure-volume measurements while preserving the normal geometry of the chordae tendineae and mitral annulus.

How to cite: Komeda, M., Bolger, A. F., DeAnda, A., Jr, Tomizawa, Y., Ingels, N. B., Jr, & Miller, D. C. (1996). Improving methods of chordal sparing mitral valve replacement. Part I: A new, non-distorting isovolumic balloon preparation for the left ventricle with intact mitral subvalvular apparatus. The Journal of heart valve disease, 5(4), 376–382.

Background and aims of the study: Replacement of ruptured mitral valve chordae using expanded polytetrafluoroethylene (ePTFE) sutures is becoming an increasingly utilized repair technique. However, setting the proper length of the replacement suture is technically challenging, and the effect of a non-optimal suture length is undefined. The purpose of this study was to assess how varying the length of replacement sutures affects mitral valve function and stresses.

Materials and methods: We employed a finite element model of the mitral valve used extensively in our laboratory. Seven different valve conditions were simulated using this model: (i)normal valve, (ii) chordal rupture without repair, and (iii-iv) chordal replacement using ePTFE sutures that were equal in length to the replaced chordae (equal length), 10% longer (Long10), 3% longer (Long3), 3% shorter (Short3), and 10% shorter (Short10) than the replaced chordae. Each model was loaded to physiologic pressures.

Results: Both the Long10 and chordal rupture models achieved complete valve closure, but chordal stresses were nearly double normal values. The Long3 model also demonstrated complete valve closure, but chordal stresses were increased to only one-third more than normal. Using sutures equal to or shorter than the length of the replaced chordae prevented complete valve closure, and produced stress concentrations at the anterior leaflet free edge. The resulting gaps and stress concentrations were most significant in the Short10 model and least significant in the equal length model.

Conclusions: These models demonstrate that replacement sutures equal to, or slightly longer than the replaced chordae optimize function and stresses in the repaired valve.

How to cite: Reimink, M. S., Kunzelman, K. S., & Cochran, R. P. (1996). The effect of chordal replacement suture length on function and stresses in repaired mitral valves: a finite element study. The Journal of heart valve disease, 5(4), 365–375.

Background and aims of the study: Artificial chordae made of ePTFE have been used for mitral valve repair for 10 years. The positive results obtained in experimental and clinical series have led to the extension of their clinical indications to mitral valve replacement and tricuspid valve repair. The different technical aspects of each of these applications are illustrated.

Materials, methods and results: Artificial chordae were implanted in 223 patients undergoing mitral valve repair. Seven of them had the valve replaced during the same operation due to an unsatisfactory result. Two patients died in the postoperative period. During a mean follow up of 38.1 months (range 2-114 months), two more patients died, while three reoperations were required; one thromboembolic event was reported and the actuarial rates of patient survival and event-free survival were 98.0% and 95.8%, respectively, at nine years. In 31 cases of mitral valve replacement, with unavoidable removal of the entire subvalvular apparatus, ventricular wall-mitral annulus continuity was restored with the insertion of artificial chordae. None of these patients died early or during a mean follow up of 25.2 months (range 2-110 months), in which only one thromboembolic event was reported. In five cases of tricuspid valve insufficiency in which traditional techniques of repair were inadequate, valve replacement was avoided with the application of artificial chordae. None of these patients experienced any early or late complications.

Conclusion: Based on this experience these procedures are safe, reproducible and reliable. They are a valuable support for other traditional techniques, allowing the indications for mitral and tricuspid valve repair to be extended, and restoring the ventricular-annular continuity in case of mitral valve replacement.

How to cite: Zussa C. (1996). Different applications of ePTFE valve chordae: surgical technique. The Journal of heart valve disease, 5(4), 356–361.

Background and aims of the study: Expanded polytetrafluoroethylene sutures have been used for the replacement of chordae tendineae of the mitral valve since 1985 at The Toronto Hospital. This study examines the long term results of mitral valve repair with chordal replacement with this material.

Materials and methods: From July 1985 to December 1993, 134 consecutive patients with mitral regurgitation due to degenerative disease of the mitral valve underwent mitral valve repair with replacement of elongated or ruptured chordae tendineae with one to six (mean of 2.8) Gore-Tex sutures. The patients' mean age was 61 years, range 22-86. In addition to mitral valve repair, 14 patients underwent aortic valve surgery, three underwent replacement of the ascending aorta, six underwent tricuspid valve repair, nine underwent the maze procedure for atrial fibrillation, and 13 underwent coronary artery bypass. The patients were followed for between 20 and 116 months, mean 51 months. No patient has been lost to follow up.

Results: There were one operative and eight late deaths. The actuarial survival at eight years was 88% +/- 6%. Four patients required reoperation, one for persistent hemolysis and three for recurrent mitral regurgitation. The Gore-Tex chordae were not responsible for the reoperation in any patient. The freedom from reoperation at eight years was 96% +/- 2%.

Conclusions: Expanded polytetrafluoroethylene sutures are excellent for chordal replacement during mitral valve repair and do not fail during the first decade following surgery. This material has allowed us to increase the probability of successful mitral valve repair in patients with degenerative disease of the mitral valve and prolapse of both leaflets.

How to cite: David, T. E., Armstrong, S., & Sun, Z. (1996). Replacement of chordae tendineae with Gore-Tex sutures: a ten-year experience. The Journal of heart valve disease, 5(4), 352–355.

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How to cite: Frater R. W. (1996). 10th Goretex chorda anniversary. The Journal of heart valve disease, 5(4), 348–351.