Cardiovascular Disease SESSION TITLE: Student/Resident Case Report Poster - Cardiovascular Disease II SESSION TYPE: Student/Resident Case Report Poster PRESENTED ON: Tuesday, October 25, 2016 at 01:30 PM - 02:30 PM
Are We There Yet With Instant Wave-Free Ratio (iFR) Pradyumna Agasthi MD* Obiora Egbuche MD Tulani Washington-Plaskett MD; and Rajesh Sachdeva MD Morehouse School of Medicine, Atlanta, GA INTRODUCTION: Instantaneous wave-free ratio (iFR) is a novel hemodynamic resting index used to assess the severity of coronary artery stenosis. iFR calculates the gradient across a coronary lesion during a period of diastole. The index has been tested against fractional ﬂow reserve (FFR) with inconsistent results. We present a case of acute coronary syndrome (ACS) where iFR couldn’t accurately identify an ischemic lesion in comparison to FFR. CASE PRESENTATION: 45 yr. old man with medical history of coronary artery disease s/p drug eluding stent (DES) to right coronary artery (RCA) 6 years ago, hypertension and dyslipidemia presented to the emergency department with worsening exertional angina. His electrocardiogram showed left ventricular hypertrophy with repolarization abnormalities. Troponins was mildly elevated to 0.06ng/ml. He underwent cardiac catheterization that showed 90% stenosis in proximal segment of RCA and a 50% stenosis in distal segment. DES stent was deployed in the proximal stenosis. iFR was performed to determine the hemodynamic severity of the distal stenosis. iFR was measured at 0.97 suggesting a non ischemic stenosis. FFR was performed with intravenous adenosine and the value measured was 0.79 suggesting an ischemic stenosis. Another DES was deployed in distal RCA. On follow up 3 months later, patient was asymptomatic.
CONCLUSIONS: One must be cautious while interpreting hemodynamics of coronary lesions using iFR and making important decisions without robust outcome data. Reference #1: Berry, Colin, et al. “VERIFY (VERiﬁcation of Instantaneous wave-Free ratio and fractional ﬂow reserve for the assessment of coronary artery stenosis severity in everydaY practice): a multicenter study in consecutive patients.” Journal of the American College of Cardiology 61.13 (2013): 1421-1427. Reference #2: Sen, Sayan, et al. “Diagnostic classiﬁcation of the instantaneous wave-free ratio is equivalent to fractional ﬂow reserve and is not improved with adenosine administration: results of CLARIFY (Classiﬁcation Accuracy of Pressure-Only Ratios Against Indices Using Flow Study).” Journal of the American College of Cardiology 61.13 (2013): 1409-1420. DISCLOSURE: The following authors have nothing to disclose: Pradyumna Agasthi, Obiora Egbuche, Tulani WashingtonPlaskett, Rajesh Sachdeva No Product/Research Disclosure Information DOI:
Copyright ª 2016 American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.
DISCUSSION: iFR is embraced over FFR as it obviates the need for adenosine, a step that can be time-consuming, costly and is contraindicated in some patients. CLARIFY trial showed that iFR is non inferior to FFR. On the contrary VERIFY trial showed a weak co-relation between iFR and FFR. Our patient had an ischemic stenosis in the distal RCA which was misclassiﬁed as non ischemic by iFR. This suggests the need for further studies to substantiate the efﬁcacy of iFR in identifying culprit stenosis.