Stentless Bioprostheses for Aortic Valve Replacement in Calcific Aortic Stenosis

The classic case of aortic stenosis is a healthy middle-aged patient with/without symptoms, but in practical life, patients with severe calcific aortic valve come with several and severe comorbidities such as advanced age, coronary artery disease, atherosclerotic aorta, significant left ventricular dysfunction. Aortic valve replacement (AVR) is the only options in these patients, and it requires patient-by-patient analysis of clinical, echocardiograhic, and hemo‐ dynamic data with associated pathologies. The curative treatment of calcific aortic valve stenosis is the replacement of the aortic valve with a prosthetic valve, and selection of a perfect prosthetic valve is the main goal to get a successful treatment. But, there is no any perfect heart valve prosthesis which may mimic the characteristics of the normal native aortic valve: excellent hemodynamics, life-long durability, thromboresistance, and excellent implantability. That means that native valve disease will be traded for prosthetic valve disease and the outcome of AVR is affected by the type of prosthetic valve. Mechanical valves are non-limited durable, but have a substantial risk of hematologic complications (thromboemboli, thrombotic obstruction, hemorrhage related life-long anticoagulation therapy) with/without hemolysis potential. In contract, bioprosthetic valves have a low risk of thromboembolism without anticoagulation, but their durability is limited by calcific or noncalcific tissue deterioration. Biological prostheses, especially homografts, are often believed to be the substitute of choice in AVR, but the limited availability of homografts prevents their more broadly usage. To overcome this problem and all possible complications of mechanical valves, xenogenic biological prostheses have been developed. The design of bioprosthetic valves purports to mimic the anatomy of the native aortic valve and their flow characteristics are better than mechanical valves, whereas stentless bioprostheses have hemodynamic performance similar to the healthy native aortic valve. Although stented bioprostheses can be implanted easier,