Stentless valves for aortic valve replacement: where do we stand?

Future of cardiac surgery: minimally invasive techniques in sutureless valve resection

Aortic valve replacement with mechanical or biological heart valves is the treatment of choice for aortic valve stenosis when it is symptomatic or with severe aortic stenosis (≤ 0.6 cm2/m2) or with left ventricular dysfunction. In an effort to improve the outcomes of patients with stented biological valves, stentless valves were introduced to clinical practices in the early 1990s. Theses valves were designed to be less obstructive, and thus result in a lower transvalvular gradient. Technically the implantations of these valves are more demanding resulting in longer cross clamp and bypass times. However, important comorbid conditions in elderly patients referred for aortic valve replacement require alternative treatment options with possible reductions of the extracorporeal bypass time and reliable hemodynamic features. In order to comply with these requirements, percutaneous valves and sutureless surgical valves have been developed. The percutaneous technique has the advantage of being performed without circulatory bypass but leaving the aortic calcifications in place, thereby resulting in a high degree of paravalvular insufficiency, atrioventricular block and strokes. The surgical approach has the advantage of removing all calcifications and the valves can be optimally implanted, resulting in minimal paravalvular leak with a low incidence of atrioventricular block and strokes; however, it requires cardiopulmonary bypass. In addition, it can be performed with a low mortality (<3% in isolated aortic replacement, even in older patients). This article reviews the various techniques, strength and limitations of these sutureless valves implanted in the aortic position.

Durability of bioprosthetic cardiac valves

INTRODUCTION

The choice of type of heart valve prosthesis is determined by the patient's age since bioprostheses have a limited lifespan. This article reviews current recommendations and the literature on cardiac valve replacement.

METHODS

Selective literature search in Medline/PubMed back to 1996 and review of current national and international recommendations from specialist societies.

RESULTS

The recommendations guiding the type of heart valve replacement have been revised in recent years. Of particular interest are the new generation of biological prostheses with extended durability, a growing use of stentless bioprostheses, a decrease in mortality of reoperation and an increase in life expectancy. Comorbidities such as chronic renal insufficiency or chronic atrial fibrillation are no longer contraindications to bioprosthesis. The number of heart valve replacements in recent years rose despite a concomitant increase in valve repairs. Aortic valves are being increasingly replaced by bioprostheses.

DISCUSSION

The choice of heart valve prosthesis should be tailored to each patient taking into account the patient's age, life expectancy, comorbidities, and life style. Different decisions may be made now than those based on earlier recommendations resulting in an individualized treatment, in patients over the age of 65 or 70.