10-year results of On-X bileaflet mechanical heart valve in the aortic position: low target INR regimen in Japanese.

OBJECTIVES

This study was designed to establish clinical outcomes after aortic valve replacement (AVR) with On-X bileaflet mechanical heart valve.

METHODS

Between 2006 and 2014, AVR was performed to 686 patients. Of them, 78 patients using On-X valve were enrolled. The mean age was 65 ± 11 years (ranged 33-85); 65% were men; and 81% were in sinus rhythm preoperatively. Calcific or degenerative tricuspid aortic valve was present in 73%. Concomitant procedures included coronary artery bypass grafting (22%), Bentall (8%), mitral valve procedure (3%) and other (9%). They postoperatively received lower dose warfarin [international normalized ratio (INR), 1.5-2.0] and 100 mg aspirin daily. The follow-up duration averaged 5 years (386.6 patient-years). The follow-up rate was 97.3%.

RESULTS

In-hospital mortality rates were 3.8% (n = 3). Late mortality rates were 2.6% per patient-years (n = 10). Five-year Kaplan-Meier survival rates were 84%. Freedom from major adverse valve-related stroke and cerebral bleeding events was 93.3% (n = 5, 1.29% per patient-years) and 98.6% (n = 1, 0.26% per patient-years, mild subdural hematoma). The incidence of stroke was two patients of transient ischemic attack, two patients of paralytic event, one patient of asymptomatic stroke (self-interruption of anticoagulation). The median INR was 1.92 ± 0.53, ranged from 1.00 to 8.98 (n = 1181) and 51% of all measured INR values were in the therapeutic range of 1.5-2.0.

CONCLUSIONS

AVR using On-X valve with low target INR regimen and low-dose aspirin resulted in a significantly low risk of bleeding.