Long‐Term Effects of Transcatheter Aortic Valve Implantation on Coronary Hemodynamics in Patients With Concomitant Coronary Artery Disease and Severe Aortic Stenosis

Abstract

Background As younger patients are being considered for transcatheter aortic valve implantation (TAVI), the assessment and treatment of concomitant coronary artery disease is taking on increased importance. Methods and Results Thirteen contemporary lower‐risk patients with TAVI with severe aortic stenosis (AS) and moderate‐severe coronary lesions were included. Patients underwent assessment of coronary hemodynamics in the presence of severe AS (pre‐ TAVI ), in the absence of severe AS (immediately post‐ TAVI ), and at longer‐term follow‐up (6 months post‐ TAVI ). Fractional flow reserve decreased from 0.85 (0.76–0.88) pre‐ TAVI to 0.79 (0.74–0.83) post‐ TAVI , and then to 0.71 (0.65–0.77) at 6‐month follow‐up ( P <0.001 for all comparisons). Conversely, instantaneous wave‐free ratio was not significantly different: 0.82 (0.80–0.90) pre‐ TAVI , 0.83 (0.77–0.88) post‐ TAVI , and 0.83 (0.73–0.89) at 6 months ( P =0.735). These changes are explained by the underlying coronary flow. Hyperemic whole‐cycle coronary flow (fractional flow reserve flow) increased from 26.36 cm/s (23.82–31.82 cm/s) pre‐ TAVI to 30.78 cm/s (29.70–34.68 cm/s) post‐ TAVI ( P =0.012), to 40.20 cm/s (32.14–50.00 cm/s) at 6‐month follow‐up ( P <0.001 for both comparisons). Resting flow during the wave‐free period of diastole was not significantly different: 25.48 cm/s (21.12–33.65 cm/s) pre‐ TAVI , 24.54 cm/s (20.74–27.88 cm/s) post‐ TAVI , and 25.89 cm/s (22.57–28.96 cm/s) at 6 months ( P =0.500). Conclusions TAVI acutely improves whole‐cycle hyperemic coronary flow, with ongoing sustained improvements at longer‐term follow‐up. This enhanced response to hyperemic stimuli appears to make fractional flow reserve assessment less suitable for patients with severe AS. Conversely, resting diastolic flow is not significantly influenced by the presence of severe AS. Resting indices of coronary stenosis severity, therefore, appear to be more appropriate for this patient population, although large‐scale prospective randomized trials will be required to determine the role of coronary physiology in patients with severe AS.

Challenges in Diagnosis and Functional Assessment of Coronary Artery Disease in Patients With Severe Aortic Stenosis

“…In two of these studies, significant improvement in CFR at 6 and 30 months after AVR was mainly attributable to an increase in coronary blood flow during maximal hyperemia, whereas resting coronary flow remained similar before and after TAVR or SAVR, respectively ( 100 , 102 ). The small prospective study by Vendrik et al regarding the longer-term effects of TAVR on invasively measured coronary hemodynamics by dual-sensor (Doppler and pressure) wire revealed an ongoing increase in hyperemic coronary flow as well as in CFR immediately after TAVR and 6 months after the procedure compared with pre-TAVR values ( 103 ). Hyperemic microcirculatory resistance was simultaneously continued to decrease in a similar manner as the CFR increased during 6 months follow-up ( 103 ).…”

The coronary and microcirculatory measurements in patients with aortic valve stenosis study: rationale and design

“…In addition, 15% of these measurements crossed the 0.89 threshold post-AVR, potentially changing the indication for treatment. A few small-sized studies included protracted follow-up measurements at 2, 6, or 12 mo (24,27,28). Again, these studies predominantly demonstrated progressively lower FFR values over time, explained by an incremental increase in hyperemic whole cycle coronary flow but stable iFR and unchanged flow during the wave-free period of diastole.…”

“…In a more recent, echocardiographic-based study, indexed LV mass decreased from 117 to 100 g/m 2 in a surgical and 114 to 108 g/m 2 in a transcatheter AVR group after 3 mo with further reductions at 1 yr (32). Whether these global changes in LV remodeling translate into improvement of microvascular function and hence might potentially change the absolute values of the FFR and RFR measurements, is not yet known, and available data from small series are not able to provide evidence for these hypotheses (24,28). In this respect, the present study, with 6 mo invasive follow-up, will hopefully provide more insight.…”

Aortic Valve Disease and Associated Complex CAD: The Interventional Approach

“…Conversely, Vendrik et al reported a significant reduction of FFR values over time up to 6 months after TAVI, whereas iFR did not show significant variations at 6 months of follow up [ 44 ]. The authors concluded that using resting indices may be more appropriate to select TAVI candidates who require CAD treatment.…”