We report herein our experience with the Toronto Stentless Porcine Valve (Toronto SPV, manufactured by St. Jude Medical Inc., Minneapolis, MN, USA) for aortic valve replacement (AVR). To date 146 SPV valves have been implanted, 29 in an initial clinical trial (from October 1987 to April 1987) and 117 in the current FDA trial (September 1991 to January 1994). In the current trial the majority of patients were male (76%), aortic stenosis was the dominant lesion (73%) and 68% of the patients received a valve size 27 mm or greater. The mean age was 61.3 +/- 12.0 years. For the entire group there has been no hospital death and no patient has required a pacemaker. Perioperative complications were myocardial infarction in three patients and suspect subacute bacterial endocarditis (medically treated) in three patients. There have been two late deaths (2%), two patients have had transient ischemic attacks (2%), and one patient suffered stroke with complete neurological recovery (1%). To date there has been no case of primary valve failure. Echocardiographic assessment of the SPV valve has demonstrated excellent effective valve orifice areas with very low transvalvular gradients and 95% of the patients had either 0 or 1+ insufficiency. These results are encouraging and justify the continued use of this valve in clinical trials. Further follow-up is required to determine its durability.