Bileaflet mechanical, prostheses for aortic valve replacement in patients younger than 65 years and 65 years of age or older: Major thromboembolic and hemorrhagic complication

OBJECTIVE: To determine major thromboembolic and hemorrhagic complications and predictive risk factors associated with aortic valve replacement (AVR), using bileaflet mechanical prostheses (CarboMedics and St. Jude Medical). DESIGN: A case series. SETTING: Cardiac surgical services at the teaching institutions of the Univ ersity of British Columbia. PATIENTS AND METHODS: Patients in 2 age groups who had undergone AVR betwee n 1989 and 1994 were studied. Group 1 comprised 384 patients younger than 6 5 years. Group 2 comprised 215 patients 65 years of age and older. RESULTS: The linearized rates of major thromboembolism (TE) occurring after AVR were 1.54%/patient-year for group 1 and 3.32%/patient-year for group 2 ; the rates for major TE occurring more than 30 days after AVR were 1.13%/p atient-year for group 1 and 1.55%/patient-year for group 2. The crude rates for major TE occurring within 30 days of AVR were 1.04% for group 1 and 3. 72% for group 2. The death rate from major TE in group 1 was 0.31%/patient- year and in group 2 was 0.88%/patient-year. Of the major TE events occurrin g within 30 daps, 100% of patients in both age groups were inadequately ant icoagulated at the time of the event, and for events occurring more than 30 days after AVR, 45% in group 1 and 57% in group 2 were inadequately antico agulated (INR less than 2.0). The overall linearized rates of major hemorrh age were 1.54%/patient-year for group 1 and 2.21%/patient-year for group 2. There were no cases of prosthesis thrombosis in either group. The mean (an d standard error) overall freedom from major TE for group 1 patients at 5 y ears was 95.6% (1.4%) and with exclusion of early events was 96.7% (1.3%); for group 2 patients the rates were 90.0% (3.2%) and 93.7% (3.0%), respecti vely. The mean (and SE) overall freedom from major and fatal TE and hemorrh age for group 1 patients was 90.1% (2.3%) and with exclusion of early event s was 91.2% (2.3%); for group 2 patients the rates were 87.9% (3.1%) and 92 .5% (2.9%), respectively. The 5-year rate for freedom from valve-related de ath for group 1 patients was 96.3% (2.1%) and for group 2 patients was 97.2 % (1.2%). CONCLUSION: The thromboembolic and hemorrhagic complications after AVR with bileaflet mechanical prostheses occur more frequently and result in more d eaths in patients 65 years of age and older than in patients years younger than 65 years.