Conservative aortic valve surgery in adults

Abstract

118 Chapter 1 reviews the current knowledge of the aortic valve. The normal anatomy and possible variations are described. The different pathological conditions are explained as wel as their natural history and the indications for intervention. The various surgical options with regard to the pathological condition are described. In particular, the results of aortic valve repair, when available, are presented. All other types of aortic valve substitutes are also described and their main advantages and disadvantages are mentioned. Finally, the aim of the present thesis is defined. Chapter 2 studies the durability of bicuspid aortic valve repair for prolapsing leaflet. Ninety-four patients were operated over an 8-year period with a mean follow-up of 5 years. Successful repair was more difficult to achieve in dilated ventricles. A total of 12 patients underwent reoperation. In three of them, the aortic valve was re-repairable. The risk of reoperation was highest the first postoperative year and then relatively constant at 2% per year. The overall freedom from aortic valve reoperation was 84% at 7 years. The repair was less durable in patients with residual aortic regurgitation after the initial procedure. Chapter 3 examines the results of valve repair in tricuspid aortic valves with leaflet prolapse. The repair was attempted in 33 patients but failed immediately in five. During a mean follow-up of 4 years, three more patients required aortic valve replacement. The freedom from aortic valve reoperation after successful initial repair was 83% at 5 years. The size of the patient group and the number of events were too small to detect risk factors for repair failure. Chapter 4 is an analysis of the results of aortic valve preservation during surgical intervention for acute Type A aortic dissection with involvement of the aortic root. From 1976 to 1999, 121 patients were operated with various techniques for aortic root reconstruction and followed for a mean of almost 4 years. Ten percent of the patient population underwent aortic valve replacement during follow-up but only one was due to intrinsic aortic valve pathology. Nine reoperations were due to aortic root dilatation. The use of fibrinous glue for aortic root reconstruction and the presence of an aortic valve annulus > 27mm were associated with a statistically significant higher incidence of aortic root reoperation. There was a trend towards better durability using GRF-glue® over Teflon® felt for aortic root reconstruction. Chapter 5 describes the initial St. Antonius Hospital experience with the aortic valve reimplantation technique as published by David. The technique replaces the aortic root with the exception of the aortic valve. Indications include aneurismal disease of the aortic root or ascending aorta but also aortic wall destruction due to aortic dissection, all complicated by (severe) aortic regurgitation. The experience with the first 13 patients was positive. The preoperative aortic regurgitation is corrected and the patients are functionally Summary 119 markedly better postoperatively. Further follow-up of this patient group remains necessary to evaluate the long-term outcome of this technique. All the above techniques avoid oral anticoagulation which is one advantage of reparative aortic valve surgery. The very long-term incidence of anticoagulation related complications after mechanical aortic valve replacement is not well known but is an important consideration, especially if a young adult, who still has a considerable life-expectancy, needs aortic valve surgery. Chapter 6 therefore analyses the incidence of anticoagulation related complications in patients who underwent a mechanical aortic valve replacement between 1963 and 1974. Follow-up was complete at a mean of almost 20 years and revealed that about half of the patients experienced one anticoagulation related event and 23% more than one event. The incidence of events was highest the first 5 postoperative years and the risk for a second event was higher than the risk for a first event. The freedom from a first anticoagulation related event was 46.8 % at 30 years. About half of the events resulted in a variable degree of permanent deficit. Chapter 7 is a comprehensive discussion in which the results of the presented studies are correlated with clinical practice. 120