Hidden culprit: Hemodynamic unmasking of angiographically insignificant in-stent restenosis

A 79-year-old male with coronary artery disease (CAD) and drug-eluting stents (DES) to the right coronary artery (RCA) and left anterior descending (LAD) artery (2001). A decade later, catheterization for angina showed mid-RCA chronic total occlusion (CTO) with left-to-right collateral flow and 30 % LAD in-stent restenosis (ISR), managed medically. He re-presented with angina, and repeat angiography revealed similar LAD ISR. Functional assessment with CathWorks FFRangio and invasive instantaneous wave-free ratio (iFR) was discordant but confirmed hemodynamically significant ISR due to an under-expanded, fractured LAD stent on intravascular ultrasound (IVUS). This case illustrates angiographic-functional discordance and the value of multimodal assessment.