Search

Background Stentless aortic bioprostheses offer excellent hemodynamics and potentially improved durability compared with other bioprostheses. The present report describes the clinical and hemodynamic outcomes for the Freestyle aortic root bioprosthesis in a large, multicenter cohort prospectively followed up for 10 years. Methods A total of 725 patients at 8 centers in North America (668 [92%] aged more than 60 years) were followed up prospectively after aortic valve replacement with the Freestyle stentless bioprosthesis. Implant technique was subcoronary in 509, total root in 178, and root inclusion in 38. Follow-up was 4,488 patient-years (mean 6.2 years/patient). Results For subcoronary, full root, and root inclusion groups, 10-year actuarial freedom from structural valve deterioration was 97.0% ± 2.2%, 96.0% ± 4.5%, and 90.9% ± 11.2%, respectively; and actuarial freedom from reoperation was 91.7% ± 3.5%, 92.3% ± 6.0%, and 92.0% ± 10.7%, respectively. Mean pressure gradient at 10 years was 8.9 ± 7.9 mm Hg for subcoronary, 7.0 ± 4.1 mm Hg for full root, and 10.0 ± 11.1 mm Hg for root inclusion groups; effective orifice area was 1.6 ± 0.5 cm 2 , 1.6 ± 0.6 cm 2 , and 1.7 ± 0.5 cm 2 , respectively. Freedom from moderate or more aortic regurgitation at 10 years was good for all three implant groups, but slightly higher for full root (97.7% ± 1.6%) compared with subcoronary (87.2% ± 2.8%) patients ( p Conclusions The Freestyle stentless aortic root bioprosthesis is a versatile option for aortic valve replacement. Measures of clinical outcomes and prosthesis durability remain excellent through 10 years.

Objectives We sought to describe the hemodynamic and clinical outcomes for the Freestyle aortic root bioprosthesis (Medtronic, Inc, Minneapolis, Minn) in a large multicenter cohort prospectively followed for 8 years. Methods A total of 700 patients (651 [93%] >60 years of age) at 8 centers in North America were followed prospectively after aortic valve replacement with the Freestyle stentless bioprosthesis; the implant technique was subcoronary in 500, total root in 162, and root inclusion in 38. Follow-up was 3395 patient-years (4.9 ± 2.3 years per patient). Clinical and echocardiographic follow-up was prospectively obtained at yearly intervals. Results For the subcoronary, total root, and root inclusion groups, actuarial freedom from valve-related death was 96.8% (SE 3.0%), 92.3% (SE 7.7%), and 90.9% (SE 11.2%), respectively, and freedom from structural deterioration was 98.6% (SE 2.0%), 100.0% (SE 0.0%), and 100.0% (SE 0.0%), respectively. Hemodynamics remained excellent at 6 years. Freedom from moderate or more aortic regurgitation was 86.0% (SE 5.1%), 98.7% (SE 3.9%), and 97.3% (SE 6.6%), respectively. Gradients were slightly lower (P = .0009), and the effective orifice area (P = .02) and freedom from aortic regurgitation were slightly higher (P = .03) with total root than subcoronary implantation. Conclusions The Freestyle stentless aortic root bioprosthesis is a versatile option for aortic valve replacement. Measures of clinical outcomes and prosthesis durability remain excellent in multicenter follow-up through 8 years in a population predominantly older than 60 years at the time of the operation.

At present no consensus exists regarding the timing of surgical revascularization after acute myocardial infarction. Patients admitted with acute myocardial infarction between January 1990 and April 1993 underwent early cardiac catheterization if they had postinfarction ischemia or positive results on a low-level exercise stress test. If indications for surgical intervention were found at the time of catheterization, patients were operated on within 1 or 2 days or were discharged and returned for the operation within 2 to 3 weeks. During this period, we performed 2175 isolated coronary artery bypass graft procedures; 23 patients were operated on within 24 hours of acute myocardial infarction with an operative mortality of 4.4 %, 30 patients underwent surgery between 24 and 72 hours after infarction with no deaths, 193 patients were operated on between 3 and 7 days after infarction with an operative mortality of 2.1%, 284 patients underwent revascularization between 1 week and 1 month after infarction with an operative mortality of 1.4%, and the 1645 patients without a recent infarction had a mortality rate of 1.9%. Multivariate statistical analysis was performed to evaluate mortality with these independent variables: reoperative surgery, sex, age, diabetes, timing of infarction, location of infarction, and type (transmural versus subendocardial). Myocardial infarction at any time interval less than 1 month before the operation was not associated with mortality when adjusted by these other risk factors. In addition, no differences were noted in length of stay, stroke rate, or prevalence of renal failure or pulmonary insufficiency. We conclude that nonemergency surgical revascularization can be done safely at any time interval after acute myocardial infarction,, certainly after 72 hours, with no increase in operative mortality and acceptable morbidity.

Objective: The merits of retaining the subvalvular apparatus during mitral valve replacement for chronic mitral regurgitation have been demonstrated in numerous retrospective clinical investigations but not in a randomized study. In this report we analyzed the early and late effects of complete versus partial chordal preservation on left ventricular mechanics. Methods: Forty-seven patients undergoing isolated surgical correction of mitral insufficiency were prospectively randomized to either total or partial chordal-sparing mitral valve replacement. Complete data from 36 patients were available for analysis. Of these individuals, 15 had preservation of the posterior leaflet only (P-MVR group), and 21 had complete preservation of all chordal structures (C-MVR group). Echocardiography was performed preoperatively, at the time of discharge, and after 1 year to determine dimensions, wall stress, left ventricular mass, and ejection function. Results: End-diastolic volume decreased in both groups initially but continued to decline only in the C-MVR cohort. Similarly, although end-systolic volume decreased over time with total chordal preservation, no notable changes were observed in the P-MVR group. In the C-MVR group, end-systolic stress decreased initially but rose slightly by 1 year. In contrast, end-systolic stress remained unchanged at discharge in the P-MVR group and increased at 1 year. In terms of systolic performance, ejection fraction declined after surgical intervention with partial chordal-sparing techniques and did not improve by 1 year. Ejection fraction returned to the preoperative level after an initial decrease in the C-MVR group. Finally, left ventricular mass was reduced in the C-MVR cohort versus no change in the P-MVR group. Conclusion: Complete retention of the mitral subvalvular apparatus during mitral valve replacement confers a significant early advantage by reducing left ventricular chamber size and systolic afterload compared with partial chordal preservation. Furthermore, left ventricular ejection performance continues to improve over time, probably because of more favorable left ventricular remodeling. J Thorac Cardiovasc Surg 2002;123:707-14

Background —Stentless aortic valves were designed to provide a more physiological flow pattern and lower transvalvular gradient, which may have an important bearing on postoperative left ventricular function and remodeling. In this study, we prospectively analyzed the 5-year clinical results with the Freestyle valve (Medtronic, Inc) and its hemodynamic performance by serial echocardiography. Methods and Results —Between January 1993 and August 1997, 95 patients with a mean age of 75 years underwent aortic valve replacement with the Freestyle prosthesis. Sixty-four percent of patients received valves ≤23 mm, and 37% had concomitant coronary artery bypass grafting. Average follow-up was 44±18 months (mean±SD), and echocardiography was performed preoperatively, at discharge, at 3 to 6 months, and annually thereafter. The 30-day operative mortality rate was 3%, with an overall actuarial survival rate of 80±6% (mean±SEM) at 5 years. Of the 10 late deaths, only 2 were cardiac related, thereby yielding a freedom from cardiac mortality of 94±3% after 5 years. No patient required reoperation on the aortic valve for any reason, including structural degeneration, nonstructural dysfunction, or prosthetic valve endocarditis. There were 9 thromboembolic and 3 anticoagulant-related bleeding events, none of which was fatal. The actuarial freedom from valve-related morbidity and mortality was 79±4% at 5 years. Hemodynamically, the mean transvalvular gradient significantly decreased after valve replacement and was reduced further by 41% by 6 months with a corresponding increase in effective orifice area. Left ventricular mass index fell to 75% of the preoperative value by 2 years. Conclusions —The Freestyle stentless valve can be implanted safely in the elderly with excellent midterm clinical results. It has superb hemodynamics in terms of residual transvalvular gradient, effective orifice area, and regression of left ventricular hypertrophy.

Background . Due to improved operative techniques, myocardial preservation, and perioperative care, open heart procedures are now being performed in older and sicker patients. As a result, the quality of life has become an important issue in the decision making process. Methods . Between January 1993 and October 1994, 604 patients above 65 years of age who underwent non-emergent open heart operations were followed prospectively over a 2-year period. The Health Status Questionnaire forms were distributed to all patients preoperatively and to hospital survivors at 3, 12, and 24 months. The questionnaire contains 36 questions and is divided into eight categories. Follow-up was 100% complete with 99.6% of questionnaires returned. Results . Significant quality of life improvements were noted in all categories after surgery. After reaching a peak at 12 months, there were small, but significant declines in scores relating to physical health and health perception at 24 months. In contrast, measurements for mental attributes continued to increase with time. By multivariate analysis, diabetes, older age, and female gender had a relatively adverse influence on quality of life despite improvement after operation. Similarly, patients with chronic obstructive pulmonary disease or having redo operations had lower health perception with some physical limitations. While procedure type (coronary artery bypass grafting) was associated with preoperative bodily pain, congestive heart failure symptoms were not an independent factor affecting quality of life. Conclusions . Quality of life improves with cardiac surgical interventions in this studied age group and should not be denied even in the elderly population.

Background: Many studies have demonstrated the superior hernodynamics of stentless porcine aortic valves compared to stented valves. This article describes the operative techniques and reviews our 5-year experience with the Medtronic Freestyle stentless valve. Methods: Between January 1993 and November 1997, 95 patients underwent implantation of the Medtronic Freestyle valve at a mean age of 76 years. All patients were seen at 6 months, 1 year, and annually thereafter for clinical assessment and Doppler echocardiography. Results: There were three operative and ten late deaths (two cardiac and eight noncardiac). Three strokes and four transient ischemic attacks occurred in the follow-up period. Four patients had bacteremia that was treated successfully with antibiotics. No patient required reoperation for valve-related problems. Serial echocardiograms revealed a decrease in mean systolic gradients across the valve during the first year and an increase in effective orifice areas. Ninety-one percent of patients had no, or trace, aortic insufficiency at the time of discharge and this has not increased over time. Conclusion: The Medtronic Freestyle valve has excellent hemodynamics and good clinical results. In our experience, no patient has required reoperation in a 5-year follow-up.

A technique is described for retaining the entire subvalvular apparatus in an anatomic fashion during mitral valve replacement that has resulted in no ventricular outflow tract obstruction or interference by retained chordal structures with prosthetic valve function in 128 patients.

Objective We sought to compare the 6-month angiographic patency rates of greater saphenous veins removed during coronary artery bypass grafting with the endoscopic vein harvest or open vein harvest techniques. Methods Two hundred patients undergoing nonemergency on-pump coronary artery bypass grafting were prospectively randomized to either endoscopic vein harvest or open vein harvest. Follow-up angiography of all vein grafts was scheduled at 6 months. Graft patency and disease grades were assigned independently by 2 interventional cardiologists. Leg wound healing was evaluated at discharge, 1 month, and 6 months for evidence of complications. Results There were 3 conversions from endoscopic vein harvest to open vein harvest because of vein factors. Leg wound complications were significantly lower in the endoscopic vein harvest group (7.4% vs 19.4%, P = .014). On multivariable analysis, endoscopic vein harvest emerged as the only factor affecting wound complications (odds ratio, 0.33). Three deaths (2 perioperative and 1 late) occurred in the endoscopic vein harvest group that were unrelated to vein graft closure. Twenty-four and 29 patients in the endoscopic vein harvest and open vein harvest cohorts, respectively, refused the follow-up 6-month angiography. Therefore a total of 144 angiograms (73 endoscopic vein harvests and 71 open vein harvests) and 336 vein grafts (166 endoscopic vein harvests and 170 open vein harvests) were available for analysis. The overall occlusion rates at 6 months were 21.7% for endoscopic vein harvest and 17.6% for open vein harvest. Additionally, there was evidence of significant disease (>50% stenosis) in 10.2% and 12.4% of endoscopic vein harvest and open vein harvest grafts, respectively. By means of ordinal hierarchic logistic regression, endoscopic vein harvest was not found to be a risk factor for vein graft occlusion or disease (odds ratio, 1.15). Significant predictors were congestive heart failure (odds ratio, 2.87), graft to the diagonal artery territory (odds ratio, 1.76), larger vein conduit size (odds ratio, 1.32), and graft flow (odds ratio, 0.90). Conclusion Endoscopic vein harvest reduces leg wound complications compared with open vein harvest without compromising the 6-month patency rate. The overall patency rate depends on target and vein-related variables and patient characteristics rather than the method of vein harvesting.

The Medtronic Freestyle bioprosthesis is a stentless porcine aortic root cross-linked in dilute glutaraldehyde solution with stress-free fixation for the valve leaflets. It has been treated by a process in which amino oleic acid is used to reduce the potential for calcification. As a complete aortic root, it has the same versatility as the aortic homograft but has the advantage that it is readily available in all sizes to the implanting surgeon. Between January 1993 and May 1994, we implanted 64 Freestyle bioprostheses as aortic valve replacements using a freehand technique; 5 size 19 mm, 15 size 21 mm, 16 size 23 mm, 13 size 25 mm, and 15 size 27 mm valves were used. There were 35 men and the mean age was 75.7 years (64 to 84 years). The operative mortality was 3.1% (2/64). Echocardiograms at the time of discharge revealed mean aortic valve gradients ranging from 18.2 mm Hg for 19 mm to 10.3 mm Hg for 27 mm valves. Effective orifice areas ranged from 1.0 cm 2 for 19 mm to 2.0 cm 2 for 27 mm valves. No patient had more than trace aortic insufficiency. Our early experience with this new stentless bioprosthesis shows it to have excellent hemodynamics especially in the smaller valve sizes. Using this valve in patients who have a small aortic root and require a tissue valve avoids the need for aortic root enlargement procedures. (J THORAC CARDIOVASC SURG 1995;109:871-6)