Evolution of Procedural and Clinical Outcomes After Balloon-Expanding Transcatheter Aortic Valve Implantation In Canada (from the Early Canadian Experience and SOURCE XT Registries)

Transcatheter aortic valve implantation (TAVI) has evolved globally, yet its evolution and performance across the Canadian landscape have yet to be formally assessed. Patients captured within the early Canadian TAVI experience with a balloon-expanding valve (n = 339; 2005 to 2009) and those enrolled in the Canadian SOURCE XT registry (n = 415; 2012 to 2015) were systematically compared with respect to baseline clinical, echocardiographic, and procedural characteristics. Valve-related and clinical outcomes were compared across the 2 time periods according to standardized definitions. Notable baseline between-group differences were noted across time, with Society of Thoracic Surgeons Predicted Risk of Mortality score being lower in the SOURCE XT cohort compared with the earlier Canadian cohort (7.4 ± 6.6% vs 9.8 ± 6.4%, p <0.001). The SOURCE XT cohort underwent TAVI through the transfemoral approach more frequently than their earlier Canadian counterparts (75% vs 48%), at the expense of transapical access, with major access site vascular complications (2.7% vs 13%), and ≥mild residual aortic regurgitation (39% vs 69%) being significantly less frequent (p <0.001 for all). At 30-days, there were no significant differences in rates of stroke (1.9% vs 2.4%) or new pacemakers (5.8% vs 5.0%); however, 30-day and 1-year mortality rates were significantly lower in the SOURCE XT cohort (3.6% vs 10.4%; 13.0% vs 24.2%, respectively, p<0.001 for both). In conclusion, TAVIs evolution in Canada with a balloon-expanding valve coincided with more optimized patient selection and increasing use of transfemoral access, which along with increasing operator experience, contributed to improved procedural and longer term clinical outcomes.