title: Experience with low-dose aspirin as thromboprophylaxis for the Tissuemed porcine aortic bioprosthesis: a survey of five years' experience.
abstract: OBJECTIVE
  In patients in sinus rhythm following aortic valve replacement (AVR) with bioprosthetic valves, aspirin prophylaxis generally keeps bleeding complications to a minimum without increasing the risks of thromboembolic events. To study the efficacy of aspirin prophylaxis in patients receiving the recently introduced Tissuemed porcine bioprosthetic implant in the aortic position we reviewed our database of 145 patients who underwent AVR between 1991 and 1996.
  
  
  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 performed in 26% of patients. Following AVR, low-dose aspirin prophylaxis (75 mg/day) was commenced in all patients in sinus rhythm. The bioprosthesis was evaluated using standard Society of Thoracic Surgery guidelines.
  
  
  RESULTS
  Follow up was 100% complete (total cumulative follow up 253.7 patient-years (pt-yr)). There were three minor thromboembolic episodes, 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 thromboembolism 0.7%/yr (three episodes), hemorrhage 0.4%/yr (one) and bacterial 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 population, 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 deaths. Patient survival at five years was 78.5 +/- 3.7%. At follow up, 94.8% of the patients were in NYHA functional class I or II.
  
  
  CONCLUSIONS
  Early clinical evaluation showed that, following AVR, bleeding complications were minimal with no increase in thromboembolic events in the first three months and on long-term follow up, when low-dose aspirin prophylaxis was started in patients in sinus rhythm. There was overall improvement in patient symptoms while valve-related complications were minimal with no episode of structural deterioration or non-structural failure.
authors.affiliation: Department of Cardiothoracic Surgery, Walsgrave Hospital, Coventry, UK.
authors.forename: I
authors.initials: I
authors.lastname: Goldsmith
authors.forename: G Y
authors.initials: GY
authors.lastname: Lip
authors.forename: S
authors.initials: S
authors.lastname: Mukundan
authors.forename: M D
authors.initials: MD
authors.lastname: Rosin
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001021:Aortic Valve / Q000601:surgery*; D001241:Aspirin / Q000008:administration & dosage*; D001705:Bioprosthesis / Q000009:adverse effects*; D003625:Data Collection; D004305:Dose-Response Relationship, Drug; D004696:Endocarditis / Q000453:epidemiology / Q000209:etiology; D005260:Female; D005343:Fibrinolytic Agents / Q000008:administration & dosage*; D005500:Follow-Up Studies; D006349:Heart Valve Diseases / Q000175:diagnosis / Q000401:mortality / Q000601:surgery*; D006350:Heart Valve Prosthesis / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D008943:Mitral Valve / Q000601:surgery; D011336:Probability; D011475:Prosthesis Failure; D016459:Prosthesis-Related Infections / Q000453:epidemiology / Q000209:etiology; D012086:Reoperation; D018570:Risk Assessment; D015996:Survival Rate; D013923:Thromboembolism / Q000209:etiology / Q000401:mortality / Q000517:prevention & control*; D016896:Treatment Outcome
chemical_list: D005343:Fibrinolytic Agents; D001241:Aspirin