Functional Assessment of Coronary Artery Disease in Patients Undergoing Transcatheter Aortic Valve Implantation

The prevalence of coronary artery disease (CAD) ranges from 25% to 50% of all patients with aortic valve stenosis (AVS). Observational studies reporting outcomes of patients undergoing transcatheter aortic valve implantation (TAVI) revealed a prevalence of CAD in the range of 40% to 75%. Current guidelines state that myocardial revascularization at the time of surgical aortic valve repair is a class I recommendation in the presence of coronary stenosis ≥70% and a class IIa recommendation for angiographic stenosis 50% to 70%. Conversely, the best management of CAD in TAVI candidates is unclear. There is no evidence, at present, of increased survival or symptoms relief with a full revascularization strategy, thus raising concerns about the real functional meaning of coronary lesions incidentally found in this specific subset during the routine diagnostic workout. In this context, fractional flow reserve (FFR) measured during diagnostic angiograms may prove useful. Nevertheless, it has been demonstrated that AVS may influence coronary hemodynamics and represents a clinical and physiological condition in which functional indexes may vary consistently. TAVI has been demonstrated to exert an immediate effect on coronary flow, and recently, the immediate improvement in the coronary physiological reserve induced by the aortic valve replacement has been demonstrated using wave intensity analysis. However, little is known about the functional effects of the pressure overload on coronary stenosis and if, and to which extent, the removal of the outflow obstruction may influence the relation between coronary stenosis and FFR in severe AVS. TAVI can be a useful clinical research model of isolated valvular intervention to unmask underlying valvular–coronary interactions in AVS. Background—Aortic valve stenosis may influence fractional flow reserve (FFR) of concomitant coronary artery disease by causing hypertrophy and reducing the vasodilatory reserve of the coronary circulation. We sought to investigate whether FFR values might change after valve replacement. Methods and Results—The functional relevance of 133 coronary lesions was assessed by FFR in 54 patients with severe aortic valve stenosis before and after transcatheter aortic valve implantation (TAVI) during the same procedure. A linear mixed model was used to verify the interaction of TAVI effect with the FFR values. No significant overall change in FFR values was found before and after the aortic valve stenosis removal (0.89±0.10 versus 0.89±0.13; P=0.73). A different trend in FFR groups (positive if ≤0.8; negative if >0.8) was found after TAVI (P for interaction <0.001). Positive FFR values worsened after TAVI (0.71±0.11 versus 0.66±0.14). Conversely, negative FFR values improved after TAVI (0.92±0.06 versus 0.93±0.07). Similarly, FFR values in coronary arteries with lesions presenting percent diameter stenosis >50 worsened after TAVI (0.84±0.12 versus 0.82±0.16; P=0.02), whereas FFR values in arteries with mild lesions (percent diameter stenosis <50) tended toward improvement after TAVI (0.90±0.07 versus 0.91±0.09; P=0.69). Functional FFR variations after TAVI changed the indication to treat the coronary stenosis in 8 of 133 (6%) lesions. Conclusions—Coronary hemodynamics are influenced by aortic valve stenosis removal. Nevertheless, FFR variations after TAVI are minor and crossed the diagnostic cutoff of 0.8 in a small number of patients after valve replacement. Borderline coronary lesions might become functionally significant after valve replacement, although FFR-guided interventions were infrequent even in patients with angiographically significant lesions. (Circ Cardiovasc Interv. 2016;9:e004088. DOI: 10.1161/CIRCINTERVENTIONS.116.004088.)