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Published on: August 17, 2022
Coronary Microvascular Dysfunction in Ischemia With Nonobstructive Coronary Arteries and Associations With Sublingual
Nathaniel R Smilowitz1, Abel Salas2, Amanda Joa3
1Leon H. Charney Division of Cardiology, Department of Medicine, NYU Grossman School of Medicine, New York, New York, USA; Soter Center for Cardiovascular Research, Department of Medicine, NYU Grossman School of Medicine, New York, New York, USA; Cardiology Section, Department of Medicine, VA New York Harbor Healthcare System, New York, New York, USA.
Background:
Coronary microvascular dysfunction (CMD) is a mechanism of ischemia with nonobstructive coronary arteries (INOCA) diagnosed by invasive coronary function testing (CFT). It is unknown whether CMD reflects a systemic microcirculatory disorder. Sidestream darkfield (SDF) microscopy permits noninvasive imaging of red blood cells (RBCs) in the sublingual microcirculation.
Objectives:
We sought to evaluate whether SDF microscopy identifies sublingual microvascular abnormalities in patients with INOCA due to CMD.
Methods:
Adults with INOCA underwent CFT for CMD, defined by abnormal coronary flow reserve <2.5 or index of microcirculatory resistance ≥25. Sublingual SDF microscopy was performed to determine the endothelial glycocalyx perfused boundary region (PBR), RBC filling percentage (%RBC), and perfused microvascular density (PMVD).
Results:
A total of 135 participants with INOCA (mean age 59.3 ± 12.1 years, 80% female) underwent CFT and sublingual SDF microscopy. CMD was present in 63 participants (46.7%). The median PBR was 1.96 (IQR: 0.4), median %RBC was 72.6 (IQR: 8.0), and median PMVD was 406 (IQR: 141). No differences in sublingual PBR, %RBC, and PMVD were observed by CMD status. No correlations between sublingual parameters and continuous measures of coronary flow reserve or index of microcirculatory resistance were observed.
Conclusions:
Noninvasive SDF microscopy did not identify sublingual microvascular abnormalities in INOCA patients with CMD.
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