Novel Mechanical Heart Valves: Hope or Burden?

Objective: Mechanical valve prostheses outstand through their exceptional longevity and are feared for detrimental effects that come with the required life-long anticoagulation therapy. The On-X prosthesis represents a bileaflet valve with low thrombogenic profile approved for lower INR ranges in 2014. The aim of this study was to evaluate hazards with the On-X prosthesis in the aortic position at INR 2.0-3.0 in a single-centre analysis. Methods: 168 implantations were performed at the General Hospital Vienna from 1997 to 2008. Patients’ characteristics, surgical details and survival were retrieved from the documentation system. Patients were followed up using a questionnaire during a cross-sectional telephone call. Valve-related adverse events and mortality were assessed according to current guidelines. Results: 41 (24%) female and 127 (76%) male patients with a mean age of 57±11 years were enrolled. The mean follow up time was 10±5 years (range 0-26). Over-all mortality was 42.3% (n=71). 8% (n=13) were valve-related. Early deaths occurred in 6% (n=10). The actuarial survival estimates were 80%, 69%, 55% and 36% at 5, 10, 15 and 20 years after surgery. Main death causes were MACE in 21% (n=36) followed by tumour progression in 6% (n=10) and bleedings in 3% (n=5). 82 patients (n=49%) remained event-free during the entire follow-up. 60 patients (36%) suffered from hazards attributable to prosthesis or OAC. Bleedings were the most common valve-related complications affecting 42 participants (3.85% per patient-years), thromboembolic events occurred in 2.21% per patient-years (n=25). Only one patient was diagnosed with valve thrombosis. Conclusions: Bleeding events due to life-long OAC pose a great challenge and need to be addressed. Lowering the INR with MHVs might be a beneficial approach to obviate valve-related complications, particularly haemorrhage, in the future. A registry was launched at our department enrolling 200 patients with the new INR regimen. Results will be expected soon.