Background and aim of the study: The study aim was to examine prospectively the clinical performance and durability of the Medtronic Mosaic bioprosthesis, a stented porcine aortic valve that combines improvements in tissue preservation, notably net zero differential pressure fixation of the leaflets, with antimineralization treatment using 2-amino-oleic acid (AOA).
Methods: A total of 158 Mosaic valves was implanted; 152 in patients aged over 70 years, and six in patients aged <70 years with contraindications to anticoagulant therapy. Mean age was 73.7 years. All valves were implanted in the supraannular position. Thirty-two patients (20%) required concomitant procedures, including coronary revascularization, ascending aorta replacement and/or mitral annuloplasty. Postoperative anticoagulation (heparin) was prescribed for ten days, followed by antiplatelet therapy. No long-term oral anticoagulants were prescribed, except in some patients with atrial fibrillation. The follow up included routine clinical and blood work-up, and echocardiography at six months and one year after surgery.
Results: There were seven early (0-30 days) and five late deaths (>30 days). One death was caused by a hemorrhagic stroke at three months in a patient without anticoagulant or antiplatelet therapy. No thromboembolic complications or structural valve deterioration were observed during follow up. At two years, freedom from endocarditis and reoperation was each 99.6%. NYHA class was excellent, with 98% of patients in class I or II at one year. Patient survival was 92% at two years. Hemodynamically, the valve was performing well, with mean systolic gradients of 13.6, 13.2, 12.6 and 9.6 mmHg for the 21, 23, 25 and 27 mm valves, respectively. There was no evidence of structural valve deterioration.
Conclusion: Long-term evaluations are mandatory to confirm the durability of any new bioprosthetic valve. Satisfactory early clinical and hemodynamic results with the new Mosaic bioprosthesis warrant its continued implantation in the aortic position for patients over the age of 70 years.