EXPERIENCE WITH LOW-DOSE ASPIRIN AS THROMBOPROPHYLAXIS FOR THE TISSUEMED PORCINE AORTIC BIOPROSTHESIS - A SURVEY OF 5 YEARS EXPERIENCE

Background and aims of the study: In patients in sinus rhythm followin g aortic valve replacement (AVR) with bioprosthetic valves, aspirin pr ophylaxis generally keeps bleeding complications to a minimum without increasing the risks of thromboembolic events. To study the efficacy o f aspirin prophylaxis in patients receiving the recently introduced Ti ssuemed porcine bioprosthetic implant in the aortic position we review ed our database of 145 patients who under went AVR between 1991 and 19 96. Methods: Mean patient age was 73.5 years (range: 56 to 94 years); 85 were males and 60 females. Preoperatively, 70% of the patients were in NYHA functional class III or IV. Concomitant procedures were per f ormed in 26% of patients. Following AVR, low-dose aspirin prophylaxis (75 mg/day) was commenced in all patients in sinus rhythm. The biopros thesis was evaluated using standard Society of Thoracic Surgery guidel ines. Results: Follow up was 100% complete (total cumulative follow up 253.7 patient-years (pt-yr)). There were three minor thromboembolic e pisodes, all occurring at least one year after surgery; there were no major thromboembolic complications and bleeding events. Valve-related complication rates (expressed as % pt-yr and number of events) were th romboembolism 0.7%/yr (three episodes), hemorrhage 0.4%/yr (one) and b acterial endocarditis 0.4%/yr (one). The reoperation rate was 0.4%/yr (one). At five years, actuarial freedom from thromboembolism was 95 +/ - 3.6% (SE); hemorrhage 99.2 +/- 0.75%; endocarditis 98.4 +/- 1.5; non -structural valve failure 100%; structural valve dysfunction 100% and reoperation 98.4 +/- 1.5%. The 30-day mortality rate in this elderly p opulation, influenced by clinical status (NYHA class III and IV; p = 0 .005), was 9.6% (95% CI, 4.8 to 14.4), with no early valve-related dea ths. Patient survival at five years was 78.5 +/- 3.7%. At follow up, 9 4.8% of the patients were in NYHA functional class I or II. Conclusion s: Early clinical evaluation showed that, following AVR, bleeding comp lications were minimal with no increase in thromboembolic events in th e first three months and on long-term follow up, when low-dose aspirin prophylaxis was started in patients in sinus rhythm. There was overal l improvement in patient symptoms while valve-related complications we re minimal with no episode of structural deterioration or non-structur al failure.