Temperature-dependent coronary reactivity after perfusion with University of Wisconsin solution in the isolated rat heart.

The purpose of this study was to determine the effects of different temperatures of University of Wisconsin solution on the reactivity of the coronary vasculature in retrogradely perfused isolated rat hearts. Hearts were perfused for 30 min at 20 degrees C or single-flush perfused at 12 degrees C and 4 degrees C. To study both endothelium-dependent and direct effects on smooth muscle, vasodilation was induced with 5-hydroxytryptamine (5-HT) and nitroglycerin (GTN). The vasodilatory effects of 5-HT and GTN during basal conditions were completely lost and instead a vasoconstriction was observed after 30-min perfusion at 20 degrees C (5-HT: 23.7 +/- 5% before to -19.2 +/- 8% after perfusion; GTN: 33.7 +/- 5.5% before and -11.9 +/- 6% after perfusion). The same response was observed after single-flush perfusion at 12 degrees C (5-HT: 26.5 +/- 5% and -6.5 +/- 3% and GTN: 35.9 +/- 6% and -11.2 +/- 4% before and after perfusion, respectively). Single-flush perfusion at 4 degrees C did not alter the response to 5-HT and GTN (5-HT: 25.9 +/- 6% and 30.4 +/- 7% and GTN: 45 +/- 5% and 32.7 +/- 7% before and after perfusion, respectively). This study suggests that the coronary reactivity after perfusion with University of Wisconsin solution is dependent of the temperature of the solution and provides good preservation of the coronary vascular function at 4 degrees C, whereas temperatures above 12 degrees C might be detrimental.

Long-term Doppler echocardiographic results of aortic or mitral valve replacement with Biocor porcine bioprosthesis.

OBJECTIVES: Our objectives were to evaluate the long-term bioprosthetic and cardiac functional outcome after insertion (over a 10-year period) of a new-generation porcine zero pressure-fixed Biocor bioprosthesis, as well as to determine the echocardiographic accuracy for selection of patients requiring reoperation. The long-term systematic Doppler echocardiographic assessment after valve replacement with this bioprosthesis is lacking. METHODS: Between January 1983 and January 1993, we inserted 756 Biocor prostheses in the aortic (619) or mitral (137) positions. All 51 patients who had a reoperation during the follow-up time were evaluated echocardiographically before reoperation. Additionally, 263 of 446 patients (59%) with aortic bioprostheses and 42 of 74 patients (57%) with mitral bioprostheses who were alive in January 1993 had long-term echocardiographic follow-up. RESULTS: Group A: Normally functioning bioprostheses were found in the aortic position in 242 of 263 patients and in the mitral position in 33 of 42 patients. Group B: Thirty patients had abnormal bioprosthetic function. Eleven patients had regurgitation, 3 had a combined lesion, and signs of calcification appeared in 16 patients with aortic valves, all with a peak gradient of above 60 mm Hg. Group C: Patients who had a reoperation (41 aortic and 10 mitral) within the follow-up period were followed up echocardiographically from the detection of a possible valve dysfunction until reoperation, and the findings accorded well with those at operation in 49 of 51 patients. CONCLUSIONS: These findings suggest that, during a long-term follow-up, most bioprostheses function normally, facilitating improved heart function. Abnormalities in a bioprosthesis usually develop gradually, enabling their detection by Doppler echocardiographic evaluations performed regularly or in case of any symptomatic deterioration.

Mechanical versus biological valve prosthesis: a ten-year comparison regarding function and quality of life.

To determine the long-term outcome of biological and mechanical heart valve prostheses, we compared the Biocor, a new generation of porcine bioprosthesis, with the St. Jude Medical mechanical prosthesis. One hundred consecutive patients operated on between 1983 and 1985 with the Biocor in the aortic, mitral, or both positions (without concomitant cardiac procedures) were followed until January 1993, together with 100 matched patients implanted with the St. Jude valve. The mean age was 66 and 67 years, respectively. The follow-up was 100% complete. Valve-related mortality differed significantly, with a freedom rate of 80.7% +/- 9.0% for the St. Jude group and 97.7% +/- 1.6% for the Biocor group. There were few thromboembolic events, with no significant difference between the groups. Anticoagulant-related hemorrhage occurred almost exclusively in the St. Jude group (2.3%/patient-year), and reoperations were required almost exclusively in the Biocor group (1.8%/patient-year). The occurrence of all valve-related complications (mortality plus morbidity) differed markedly, with an actuarial freedom at 10 years of 55.8% +/- 9.8% for St. Jude and 80.0% +/- 4.4% for the Biocor. Quality of life and echocardiographic measurements did not differ significantly between the groups. We conclude from this study that the long-term performance of the Biocor and St. Jude are comparable, even though valve-related complications tended to be fewer in the Biocor group, with a significantly lower incidence of valve-related death.

10-year experience with the Biocor porcine bioprosthesis in the aortic position.

Six hundred and nineteen consecutive patients had aortic valve replacement between January 1983 and January 1993 with the zero pressure fixed Biocor porcine bioprosthesis. Mean age was 66.2 years (range 17-88 years). Male/female ratio was 416/203. Concomitant cardiac procedures, mainly coronary bypass surgery, were performed in 35% (214/619). Early mortality was 5.9% (37/619). Late mortality was 15.8% (92/582). Actuarial survival at 10 years was 60.0 +/- 4.9% and freedom from valve-related mortality was 97.6 +/- 0.8%. Total follow up was 2308 years. The follow up was 99.2% complete. Thromboembolic rate was 1.1%/pty (fatal 0.1%/pty, major 0.3%/pty and minor 0.6%/pty). The incidence of prosthetic valve endocarditis was 0.3%/pty (fatal 0.1%/pty). Freedom from reoperation due to structural valve deterioration, non-structural dysfunction and prosthetic valve endocarditis was 78.1 +/- 10.7%, 98.5 +/- 0.6% and 97.6 +/- 0.9%, respectively. The occurrence of structural valve deterioration varied considerably between age groups. In patients below 50 years of age the actuarial freedom from structural valve deterioration was 52.4 +/- 22.0%, while it was 96.2 +/- 1.1% for those between 71 and 80 years. At the 10-year follow up all patients had improved clinically. Preoperatively, 75% of the patients were in NYHA classes III or IV compared to 8% at the 10-year follow up. We conclude, that the Biocor bioprosthesis has a low rate of complications in terms of thromboembolism, anticoagulant-related bleeding, prosthetic valve endocarditis and valve-related mortality as compared to mechanical valves and also to other bioprostheses. The durability of the Biocor bioprosthesis has increased slightly compared to that reported with other, earlier models when inserted in patients above 50 years of age.

10-year experience with the Biocor porcine bioprosthesis in the mitral position.

One hundred and thirty-seven consecutive patients had mitral valve replacement between January 1983 and January 1993 with Bicor porcine bioprosthesis. Concomitant cardiac procedures were performed in 37% (51/137). Mean age was 63 years. Follow up was 98% complete at a mean of 53 months. Early mortality was 13% (18/137). Within the 10-year follow up another 34 patients died, 21 due to cardiac and three to valve related causes. Overall survival at 10 years as 54.7 +/- 4.9%, and freedom from valve related mortality 94.9 +/- 2.8%. Functional class improved in all surviving patients with 84% being in NYHA class I or II at the end of the tenth year. There were 10 reoperations, three for structural valve deterioration (SVD), three for non-structural valve dysfunction (non-SVD) and four because of prosthetic valve endocarditis (PVE). Actuarial freedom from reoperation for all causes was 78.9 +/- 9.2%. None of the patients were on long term anticoagulation at hospital discharge but 57% received chronic anticoagulant treatment at the end of the 10-year follow up. Embolism occurred in 13 patients (2.5%/pty, fatal 0.4%/pty). Three patients had anticoagulant related hemorrhage (0.6%/pty, fatal 0.2%/pty). Doppler echocardiography was carried out in 52% within the last three years of follow up. Actuarial freedom from SVD (confirmed at reoperation or by echocardiography) was 80.3 +/- 9.8%. At 10 years 93.2 +/- 2.8% were free from PVE. The incidence of total mortality and morbidity was 5.9%/pty (fatal 0.8%/pty) with an actuarial freedom of 59.6 +/- 8.8% from all valve related complications.(ABSTRACT TRUNCATED AT 250 WORDS)