Impact of Aortic Valve Intervention on Coronary Flow Reserve
Myocardial flow might be compromised in patients with severe aortic stenosis, which might be driven by CAD and concomitant atherosclerosis or a compromised capillary bed. Capillary circulation might be compromised by increased left ventricular mass (LVM) which in turn might alter coronary flow reserve (CFR).
Multiple studies have shown images of LMV regression after adequate aortic valve intervention. However, the physiological impact of aortic valve intervention on coronary circulation remains unclear.
The aim of this study by Sabbah M, et al. was to look into the impact of TAVR or SAVR (transcatheter or surgical valve replacement) in CFR and to determine whether these changes are related to a difference in LV stroke work (LVSW, mean transvalvular gradient and LV stroke volume).
This was a prospective, observational study carried out in two Danish centers. It excluded patients with ventricular function ≤45%, glomerular filtration ≤30ml/min, patients presenting associated coronary lesions, and patients with other moderate/severe valvulopathies. Coronary angiograms were done to measure CFR as well as cardiac MRI prior intervention and 6 months after.
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The study looked at the anterior descending only and assessed indexes included CFR, microcirculation resistance index (MRi) with PressureWire X, hyperemia coronary flow (QLAD) and microvascular minimal resistance (Rμ,LAD) with infusion catheter RayFlow. Mean transit time (MTT) was used as surrogate measurement of volumetric flow.
34 patients were analyzed, mean age 72±8, 71% trivalves, 50% received TAVR, 41% SAVR with bioprosthesis and 9% SAVR with mechanical valve. 50% of patients did not present ventricular hypertrophy when measured with MR.
At followup, there was mean reduction of 18.5g/m2 (Δ20%) on mass ventricular index (p≤0.001) confirmed by MR, LVSW was reduced from 20.8 to 17.9 cJ (p=0.04). Fractional flow reserve (FFR), IMR, QLAD and Rμ,LAD saw no significant change at followup.
CFR improved significantly in 71% of patients (82% of TAVR patients and 59% SAVR), with no significant changes in hyperemic flow (QLAD; 230±106mL/min to 250±101mL/min; p=0.26) or minimal microvascular resistance (Rμ,LAD; 347 [247-463] to 287 [230-456]; p=0.20). Resting MTT was higher while hyperemic MTT saw no change.
Conclusions
This study looked at the long term effects on left anterior descending physiology after TAVR or SAVR intervention. CFR increased significantly with no change in QLAD or Rμ,LAD and this increase was mainly associated to LVSW reduction.
Dr. Omar Tupayachi.
Member of the Editorial Board of SOLACI.org.
Original Title: Long-term changes in coronary physiology after aortic valve replacement.
Reference: Sabbah M, Olsen NT, Holmvang L, et al. Long-term changes in coronary physiology after aortic valve replacement [published online ahead of print, 2022 Oct 13]. EuroIntervention. 2022;18(14):1156-1164. doi:10.4244/EIJ-D-22-00621.
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