Instantaneous Wave-Free Ratio for Evaluation of Circumflex Artery Compression During Indirect Mitral Annuloplasty

Indirect mitral annuloplasty with the Carillon Mitral Contour System offers a promising treatment for functional mitral regurgitation, but it may be complicated by circumflex artery (Cx) compression. In a cohort of 92 patients treated between January 2019 and December 2021, Cx impingement occurred in 15 patients (16.3%), including 11 cases (11.95%) of Cx compression and 4 cases (4.35%) of total occlusion. Instantaneous wave-free ratio (iFR) was used in a series of 5 patients with Cx compression (5.43%) to assess hemodynamic relevance. The procedure was terminated in 3 patients (3.26%) because of Cx occlusion and in 1 patient (1.09%) because of a pathologic iFR without any further possibility of device repositioning. This case series is to our knowledge the first to demonstrate the utility of iFR in evaluating the hemodynamic relevance of coronary compression during Carillon implantation.