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To The Editor We read with great interest the study published by Fröhlich et al1 regarding long-term survival in patients undergoing fractional flow reserve (FFR)-guided percutaneous coronary intervention (PCI) or intravascular ultrasonography (IVUS)-guided PCI vs PCI guided by angiography alone. In this large cohort study, using a PCI registry in London, England, the authors expertly demonstrate that neither FFR nor IVUS, when used as adjuncts to PCI, translate into improved long-term survival in these “real-world” patients.1 These findings are not entirely surprising, since prior randomized studies and meta-analyses have failed to show a mortality benefit for PCI in addition to optimal medical therapy in the management of stable coronary disease.2,3 However, this study consisted of a more heterogeneous population than those that have been previously studied. Nearly 40% of the study population consisted of patients with non–ST-segment elevation myocardial infarction, where early PCI for high-risk patients is associated with a mortality benefit and is recommended by the American College of Cardiology Foundation/American Heart Association guidelines.4 Yet, there was no overall difference in mortality across the PCI strategies. This is perhaps explained by the fact that FFR and IVUS are only adjunctive devices used to guide and/or facilitate PCI, which is the ultimate interventional therapy in question. In addition, the patient population also significantly differed in the degree of intermediate coronary stenosis (7.5% in the angiography group had stenosis <75% as opposed to 38.7% in the FFR group and 18.5% in the IVUS group),1 which may influence the baseline risk of mortality. Therefore, comparing outcomes in these highly heterogenous groups is fraught with risk, despite careful attempts by the authors to minimize confounding using propensity matching.
Atreya AR, Lotfi A. Adjunctive Diagnostic Procedures for Percutaneous Coronary Intervention. JAMA Intern Med. 2015;175(4):647-648. doi:10.1001/jamainternmed.2014.8003