Transcatheter Replacement of Stenotic Aortic Valve Normalizes Cardiac–Coronary Interaction by Restoration of Systolic Coronary Flow Dynamics as Assessed by Wave Intensity Analysis

Abstract

Background-Aortic valve stenosis (AS) can cause angina despite unobstructed coronary arteries, which may be related to increased compression of the intramural microcirculation, especially at the subendocardium. We assessed coronary wave intensity and phasic flow velocity patterns to unravel changes in cardiac-coronary interaction because of transcatheter aortic valve implantation (TAVI). Methods and Results-Intracoronary pressure and flow velocity were measured at rest and maximal hyperemia in undiseased vessels in 15 patients with AS before and after TAVI and in 12 control patients. Coronary flow reserve, systolic and diastolic velocity time integrals, and the energies of forward (aorta-originating) and backward (microcirculatoryoriginating) coronary waves were determined. Coronary flow reserve was 2.8±0.2 (mean±SEM) in control and 1.8±0.1 in AS (P<0.005) and was not restored by TAVI. Compared with control, the resting backward expansion wave was 45% higher in AS. The peak of the systolic forward compression wave was delayed in AS, consistent with a delayed peak aortic pressure, which was partially restored after TAVI. The energy of forward waves doubled after TAVI, whereas the backward expansion wave increased by >30%. The increase in forward compression wave with TAVI was related to an increase in systolic velocity time integral. AS or TAVI did not alter diastolic velocity time integral. Conclusions-Reduced coronary forward wave energy and systolic velocity time integral imply a compromised systolic flow velocity with AS that is restored after TAVI, suggesting an acute relief of excess compression in systole that likely benefits subendocardial perfusion. Vasodilation is observed to be a major determinant of backward waves. (Circ Cardiovasc Interv. 2016;9:e002356.

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

“…11 At wave intensity analysis, the microcirculatory decompression (suction) was found to decrease and the forward compression wave to increase after TAVI, reflecting the reduction in myocardial work required to eject blood past a stenosed aortic valve and the immediate improvement in the coronary physiological reserve induced by the aortic valve replacement. 11,12,29 TAVI, inducing an immediate decrease in hyperemic microvascular resistance and an increase in hyperemic flow velocity, is associated with an immediate improvement in the reserve vasodilator capacity of the coronary microcirculation. 10 Increased extravascular compression and reduced diastolic perfusion time, rather than vascular remodeling, influence coronary microvascular dysfunction in AVS.…”

“…[7][8][9] TAVI has been demonstrated to exert an immediate effect on coronary flow, 10 and recently, the immediate improvement in the coronary physiological reserve induced by the aortic valve replacement has been demonstrated using wave intensity analysis. 11,12 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.…”

Current state of the art and future of myectomy

“…One of the important factors contributing to CMC in HCM is related to "contraction-coronary coupling" as shown by wave intensity analysis (11) (Figure 8). This type of CMC is markedly aggravated by LVOTO and is expected to improve immediately after relief of LVOTO in a manner similar to that observed after relief of aortic stenosis (12). Further improvement in the coronary microcirculation after relief of LVOTO can occur due to reverse myocardial remodeling, which occurs after myectomy (13).…”

Regression of left ventricular hypertrophy provides an additive physiological benefit following treatment of aortic stenosis: Insights from serial coronary wave intensity analysis

“…Previous work has demonstrated that both LVH 9 and the presence of an outflow tract obstruction 10,12 have individual effects on coronary WIA. In this study, we have identified and separated these contrasting effects within individual patients with severe aortic stenosis and as such have shown that three states exist: With intervention, there is no immediate change in LV mass index (A).…”

“…Furthermore, ventricular remodelling may even confound some studies where a follow-up measure is performed outside of the immediate peri-operative setting as the most rapid hypertrophy regression occurs largely within the first 6 months. 10,12 Furthermore, in patients without significant valvular disease, LVH results in a relative reduction in the BDW reflecting a disruption in ventricular-coronary interaction. It has proven able to document the potentially opposing influences of LVH 9 and aortic stenosis 10 on coronary physiology where abnormalities can be appreciated in the backward decompression wave (BDW).…”