Practice Update: Cardiology

CONFERENCE COVERAGE 8

ACC 2017: Round-up of key trials by Dr Joerg Herrmann

Dr Herrmann, Associate Professor of Medicine at Mayo Graduate School of Medicine in Minnesota, shares his take-home messages from some of the key trials presented at the American College of Cardiology’s 66th Scientific Session & Expo, 17-19 March, Washington DC, USA.

iFR-SWEDEHEART and DEFINE-FLAIR Two studies, one result: iFR (instant wave-free ratio)- guided percutaneous coronary intervention (PCI), at a threshold of 0.89, is noninferior to FFR (fractional flow reserve)-guided PCI, at a threshold of 0.8, in terms of key clinical endpoints (ie, major adverse cardiac events) and is better tolerated from a patient perspective. 1–2 Both studies also showed that FFR identified more lesions deemed to be hemodynamically significant and led to more interventions. The overall agreement of the two studies is remarkable as the iFR-SWEDEHEART study was a randomized clinical trial based on a comprehen- sive registry 1 whereas DEFINE-FLAIR was a traditional prospectively enrolling randomized clinical trial. 2 Most certainly, these two studies will promote the use of iFR in clinical practice, a procedure that is much easier, faster, and less costly to perform. An aspect challenged by the current data is the definition of cutoffs. The best match of iFR to an FFR value of 0.8 with a 96% sensitiv- ity and 91% specificity is in the range of 0.85 to 0.94. A hybrid approach has thus been advocated – that is, to defer PCI if the iFR is greater than 0.93, to perform PCI if the iFR is less than 0.86, and to perform FFR if the iFR is between 0.86 and 0.93. These two studies simplified this approach to an iFR cutoff of 0.89. Statistically, an iFR of 0.89 matches an FFR cutoff of 0.8 only with a 73% sensitivity and an 88% specificity, but clinically it seems closer to 100%. References 1. Götberg M, Christiansen EH, Gudmundsdottir IJ, et al., on behalf of the iFR-SWEDEHEART Investigators. N Engl J Med DOI: 10.1056/NEJMoa1616540. 2. Davies JE, Sen S, Dehbi HM, et al. N Engl J Med DOI: 10.1056/ NEJMoa1700445.

SURTAVI In August, the FDA approved the use of the bal- loon-expandable SAPIEN 3 and SAPIEN XT valves for transcatheter aortic valve replacement (TAVR) in inter- mediate-risk patients. Here now comes the answer for the self-expandable valves such as the CoreValve and Evolute R valve in patients with severe aortic stenosis at intermediate surgical risk (that is, those with an estimated risk of 30-day surgical death of 3% to 15%, according to the criteria of the Society of Thoracic Surgeons Pre- dicted Risk of Mortality [STS-PROM]) – the SURTAVI trial. 1 The key finding is that of no difference in death from any cause or disabling stroke at 24 months between TAVR and surgical aortic valve replacement (SAVR); that is, the study met its noninferiority primary endpoint. Surgery was associated with higher rates of acute kidney injury (4.4% vs 1.7%), atrial fibrillation (43.4% vs 12.9%), and transfusion requirements (40% vs 12.5%), whereas TAVR patients had a higher need for pacemaker implantation (25.9% vs 6.6%) and higher rates of residual aortic regurgitation (75% vs 33%); however, nearly none severe, 5% moderate aortic regurgitation – thus almost all patients were split only between trace or mild aortic regurgitation). Paravalvular leak was noted in 60% to 70% of TAVR patients; again, nearly none severe, 5%moderate aortic regurgitation, and thus almost all either only a trace or mild degree. TAVR resulted in better aortic valve hemodynamics (greater aortic valve area and lower aortic valve gradient) than surgery, and neither TAVR nor surgery showed evidence of structural valve deterioration at 24 months. Aortic valve re-intervention rates remained low, but were 1%, 2%, and 3% at 1, 12, and 24 months in the TAVR group vs 0.2%, 0.5%, and 0.7% with SAVR. Overall, SURTAVI results do not come as a surprise; self-expandable TAVR is on par with SAVR with regard

PRACTICEUPDATE CARDIOLOGY