Objectives We hypothesised that low flow low gradient aortic stenosis (LFLGAS) is associated with more severe coronary microvascular dysfunction (CMD) compared with normal-flow high-gradient aortic stenosis (NFHGAS) and that CMD is related to reduced cardiac performance.
Methods Invasive CMD assessment was performed in 41 consecutive patients with isolated severe aortic stenosis with unobstructed coronary arteries undergoing transcatheter aortic valve implantation (TAVI). The index of microcirculatory resistance (IMR), resistive reserve ratio (RRR) and coronary flow reserve (CFR) were measured in the left anterior descending artery before and after TAVI. Speckle tracking echocardiography was performed to assess cardiac function at baseline and repeated at 6 months.
Results IMR was significantly higher in patients with LFLGAS compared with patients with NFHGAS (24.1 (14.6 to 39.1) vs 12.8 (8.6 to 19.2), p=0.002), while RRR was significantly lower (1.4 (1.1 to 2.1) vs 2.6 (1.5 to 3.3), p=0.020). No significant differences were observed in CFR between the two groups. High IMR was associated with low stroke volume index, low cardiac output and reduced peak atrial longitudinal strain (PALS). TAVI determined no significant variation in microvascular function (IMR: 16.0 (10.4 to 26.1) vs 16.6 (10.2 to 25.6), p=0.403) and in PALS (15.9 (9.9 to 26.5) vs 20.1 (12.3 to 26.7), p=0.222). Conversely, left ventricular (LV) global longitudinal strain increased after TAVI (−13.2 (8.4 to 16.6) vs −15.1 (9.4 to 17.8), p=0.047). In LFLGAS, LV systolic function recovered after TAVI in patients with preserved microvascular function but not in patients with CMD.
Conclusions CMD is more severe in patients with LFLGAS compared with NFHGAS and is associated with low-flow state, left atrial dysfunction and reduced cardiac performance.
- transcatheter aortic valve replacement
- aortic valve stenosis
- cardiac catheterization
- heart failure, systolic
Data availability statement
Data are available on reasonable request.
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RS and MP contributed equally.
Contributors All authors have contributed to conception and design or analysis and interpretation of data, or both, to drafting of the manuscript or revising it critically for important intellectual content and to final approval of the manuscript submitted. RS acts as guarantor of the study, accepting full responsibility for the work and/or the conduct of the study, had access to the data, and controlled the decision to publish.
Funding This study received a research grant from Abbott Vascular (n.1333-12/2020).
Competing interests This study received a research grant from Abbott Vascular (n.1333-12/2020). RS is on advisory boards for Abbott. FR received research grants from Philips and Abbott.
Patient and public involvement Patients and/or the public were not involved in the design, or conduct, or reporting, or dissemination plans of this research.
Provenance and peer review Not commissioned; externally peer reviewed.
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