Dilation of the sinotubular junction causes aortic insufficiency after aortic valve replacement with the Toronto SPV bioprosthesis

Objective: This study was undertaken to examine the causes of late aortic i nsufficiency in patients who had aortic valve replacement with the Toronto SPV bioprosthesis (St Jude Medical, Inc, St Paul, Minn). Methods: From 1991 to 1996, 174 patients with a mean age of 63 +/- 11 years underwent aortic valve replacement with the Toronto SPV bioprosthesis and were evaluated annually by Doppler echocardiographic studies to assess valv e function. The diameters of the aortic root were retrospectively measured in all patients who had aortic insufficiency and also in a random sample of 23 patients without aortic insufficiency. The mean follow-up was 5.8 years (range 4 to 9 years). Results: Aortic insufficiency greater than 1+ developed in 19 patients. The diameter of the sinotubular junction increased in these patients and did n ot change in those without aortic insufficiency. The ratio between the diam eter of the sinotubular junction and the size of the Toronto SPV bioprosthe sis increased in patients who had aortic insufficiency and did not change i n those without aortic insufficiency. Both 2-way analysis of covariance and analysis by a mixed linear model demonstrated a significant difference in slopes between the patients with aortic insufficiency greater than 1+ and i n those without insufficiency for the ratio of the diameter of the sinotubu lar junction/diameter of the Toronto SPV relationships over time (aortic in sufficiency (.) Year; P < .001). Structural valve deterioration was observe d in 5 valves, and in 4 of them the sinotubular junction of the aortic root had dilated. The freedom from structural valve deterioration was 99% +/-1 % for patients without aortic insufficiency and 82%+/- 12% for those with a ortic insufficiency of more than 1+ at 8 years (P =.004). One patient had m oderate aortic insufficiency without structural valve deterioration and dil ation of the sinotubular junction. Conclusions: Dilation of the sinotubular junction causes aortic insufficien cy after aortic valve replacement with the Toronto SPV bioprosthesis and in creases the risk of structural valve deterioration. Banding the sinotubular junction may prevent dilation and enhance the durability of this valve.