Orthotopic Transplantation of Aortic Valve Allografts. Early Hemodynamic Results

Summary

The aortic root as a functional unit includes the sinuses of valsalva, valve ring, the leaflets and the commissures. This unit is impaired by the insertion of a bioprosthetic three-leaflet valve. Moreover, bioprostheses fail because of fatigue and flexion stresses. Consequently a program was started for free-handed orthotopic transplantation of allogeneous aortic valves at the Department of Cardiovascular Surgery, University Kiel. A series of 16 consecutive antibiotic, sterilized aortic valve allografts were transplanted in the last 12 months without death, There were 4 females and 12 males between 18 and 63 years old (mean 47.9). The dominant lesion was aortic regurgitation (in 9), Stenosis (in 3) and mixed (in 4). Out of the 13 patients who maintained their allografts, 10 (77%) were in class III and 3 (23%) in class IV of the NYHA functional Classification. Four patients improved from class III to class I, and 9 from class III and IV to class II of the NYHA functional Classification after surgery. All patients except one had postoperative recatheterization including videodensitometry to quantitate the regurgitation, expressed as a regurgitant fraction (RGF) in percent of the total stroke volume of the left ventricle, and pressure measurements to determine systolic gradients across the aortic valve allograft, 3 to 6 days and 9 months after surgery. Eleven (68.75%) patients had no regurgitation, 2 (12.5%) patients had trivial aortic regurgitation with RGF of 7% and 10%, respectively. Three (18.75%) patients had severe aortic valve regurgitation with RGF between 40% and 60% due to technical errors and their allografts had to be replaced. In all 3 patients the early postoperative allograft valve incompetence was due to annulus distortion and loosely fixed new commissures. In 11 patients, the gradient was 0 to 5 mmHg across the allograft valve, and in 2 others gradients of 10 and 15 mmHg, respectively, were observed. Immunologie and viability studies of the ‘fresh’ stored allogeneous valves are included in the transplantation program. The internal diameter of the patients' valve annulus and that of the allograft valve annulus was 2 to 4 mm. Postoperatively, recorded gradients and RGF were not related to discrepancies between the patients' annulus and the allograft valve sizes.

Key words

Aortic valve allograft - Orthotopic transplantation - Functional anatomy of aortic root - Postoperative hemodynamic and videodensitometric study