Mid-term follow-up in patients with Biocor porcine bioprostheses.

BACKGROUND: Prosthetic cardiac valves have increased life expectancy of patients (pts) with valvular heart disease. Bioprosthetic complications required devices replacements within 10 years of implantation; structural valve deterioration (SVD) has emerged as the major cause of reoperation. We reviewed survival and prosthetic complications of Biocor porcine bioprostheses implanted in mitral, aortic and mitro-aortic position.

METHODS: Between January 1991 and January 2001 446 pts (192 males; 254 females; mean age 73.4+/-6.7 year, range 40-91) received 258 aortic, 138 mitral and 50 mitro-aortic Biocor porcine valves; of these 83 pts have previous different types of prosthetic devices (15 aortic, 53 mitral and 15 double). Concomitant cardiac procedures, namely myocardial revascularization, were performed in 91/446 pts (20.5%). All explanted bioprostheses (BPS) were available for pathologic investigation. Follow-up included 1319 pt.-years and was 98% complete with a median time of 36 pt.-months.

RESULTS: Perioperative mortality was 6.8% (30/446 pts; 12 aortic, 17 mitral and 1 double) and was mostly related to reoperations. At the end of follow-up 18.5% of pts died (77/416), 12 deaths were valve-related with freedom from valve related mortality of 94% at 9 years. Survival was 54% at 9 years. It was 63%, 41% and 62% for aortic, mitral and double valve replacement, respectively. At follow-up 87% of pts. were in NYHA I-II class and 13% were in III-IV class; 55% were in sinus rhythm, 36% in atrial fibrillation and 9% had a pace-maker. Eighty-five percent of pts were anticoagulated. There were 6 thromboembolic and 5 anticoagulant-related haemorrhagic episodes with no significant difference between aortic and mitral position (p=0.7). The event freedom was respectively 92% and 98.5% at 9 years. Prosthetic valve endocarditis (PVE) and non-SVD freedom were 96% and 93% at 9 years. SVD due to tissue degeneration, calcification and cusp's tears affected 2 pts with 94% freedom at 9 years. Overall freedom from all valve-related complications was 80% at 9 years and freedom from reoperation was 92% at 9 years.

CONCLUSIONS: (1) Our intermediate-term follow-up of the Biocor porcine valve (BPS) showed excellent durability in all positions. (2) The aortic patients and especially the oldest group had better results than the mitral patients (41% vs. 63% 9 years survival, p=0.0004). (3) Higher mitral risk was related to higher prevalence of reoperations. (4) The incidence of anticoagulation-related complications is low in both aortic and mitral position without significant difference (p=0.7). 4) A longer follow-up is required to get more information about SVD timing.