Determinants of ascending aortic dimensions after aortic valve replacement with a stented bioprosthesis.

Background And Aim Of The Study: Concomitant replacement of the mildly dilated ascending aorta during aortic valve replacement (AVR) is controversial because progress of aortic dilatation is uncertain after elimination of the valvular lesion. The study aim was to determine factors influencing the aortic dimensions, to analyze their clinical impact, and to identify criteria for concomitant surgery on the aorta.

Methods: Between February 1994 and May 1999, 100 patients with tricuspid aortic valve disease received the stented porcine Mosaic prosthesis within a FDA approval study. Follow up (mean 4.8 years; range: 0.1-8.8 years; total 483.4 patient-years) included documentation of adverse events and transthoracic echocardiography with measurements of the aortic sinus, sinotubular junction, and ascending aorta.

Results: Baseline aortic dimensions were dependent on gender and body surface area, but independent of the type and extent of valvular lesion, patient age, and atherosclerotic risk factors. Larger baseline aortic diameters were associated with smaller postoperative annual aortic expansion rates (r = -0.47, p <0.001). In patients with baseline aortic dilatation > or =40 mm (10.2%; mean 42.5+/-2.6 mm), aortic diameter decreased during follow up (p = 0.032; expansion rate -1.9+/-2.0 mm/year). Baseline aortic dilatation did not influence postoperative morbidity and mortality. Prosthetic regurgitation was associated with increases in aortic diameter (p <0.001). Survival was reduced in patients with aortic expansion rates >3.6 mm/year (0.0% versus 68.2+/-9.7%; p <0.001).

Conclusion: AVR without concomitant surgery on the aorta in patients with mild aortic dilatation is feasible, as aortic diameters were decreased after removal of the diseased valve. The aortic expansion rate had a strong prognostic importance, even on aortic diameters, which are considered to be within normal ranges.