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Ischemia with no obstructive coronary arteries (INOCA) is defined as patients with evidence of myocardial ischemia without obstructive coronary artery disease. About 3–4 million people in the United States have INOCA, more commonly affecting women, and carries adverse morbidity, mortality, and relatively high healthcare costs. The pathophysiology of INOCA appears to be multi-factorial with a variety of contributing mechanisms. Diagnosis of INOCA is suggested by non-invasive or invasive testing consistent with myocardial ischemia. Due to the high prevalence of coronary risk factors and atherosclerosis in the INOCA population, current treatment strategies target angina, coronary atherosclerosis, and atherosclerotic risk factors, as well as burgeoning treatment of coronary microvascular dysfunction (CMD). Ongoing clinical trials are assessing different options.

Instantaneous wave-free ratio (iFR) has been proposed as a hemodynamic parameter that can reliably reflect the blood flow in stenosed coronary arteries. Currently, there are few investigations on the quantitative analysis of iFR in the patients regarding the variation of microcirculatory resistance (MR). The data aim to provide geometric (cross-section area of branches) and hemodynamic (flow rate and iFR of branches) parameters of normal and stenosed coronary arteries derived from CFD simulation. The CFD simulation was performed on the three-dimensional artery models reconstructed from computed tomography (CT) images of four subjects. The hemodynamic parameters were obtained in six situations of MR to simulate coronary microvascular dysfunction (CMD). This dataset could be used as the reference to estimate the iFR and flow rate in patients with CMD and stenosis in coronary arteries. The geometric parameters could be used in the modelling of coronary arteries.

Ischemia with no obstructive coronary arteries (INOCA) is defined as patients with evidence of myocardial ischemia without obstructive coronary artery disease. About 3-4 million people in the United States have INOCA, more commonly affecting women, and carries adverse morbidity, mortality, and relatively high healthcare costs. The pathophysiology of INOCA appears to be multi-factorial with a variety of contributing mechanisms. Diagnosis of INOCA is suggested by non-invasive or invasive testing consistent with myocardial ischemia. Due to the high prevalence of coronary risk factors and atherosclerosis in the INOCA population, current treatment strategies target angina, coronary atherosclerosis, and atherosclerotic risk factors, as well as burgeoning treatment of coronary microvascular dysfunction (CMD). Ongoing clinical trials are assessing different options., Competing Interests: Declaration of competing interest Dr. C. Noel Bairey Merz, serves as Board of Director for iRhythm, fees paid through CSMC from Abbott Diagnostics and Sanofi. Dr. Janet Wei served on an advisory board for Abbott Vascular.

Background: Microvascular resistance (MR) is increased in takotsubo syndrome (TTS) and can be assessed by a validated pressure-wire-free tool called nonhyperemic angiography-derived index of microcirculatory resistance (NH-IMRangio)., Objectives: The authors aimed to study whether the degree and extent of an altered MR in TTS patients were associated with 1-year prognosis., Methods: The authors recruited 181 consecutive patients with TTS who underwent cardiac angiography. Impaired MR was defined as an NH-IMRangio ≥25. The degree and extent of impaired MR were assessed by the value of maximum NH-IMRangio in each major coronary artery and by the number of coronary arteries with an NH-IMRangio ≥25, respectively. Major adverse cardiac events (MACE) were a composite of cardiovascular death, heart failure event, acute myocardial infarction, and hospitalization for symptomatic arrhythmias., Results: A total of 166 patients had NH-IMRangio available. The mean age was 74.8 years, and 83% were women. The rate of MACE at 1 year was 21.1%, mainly due to heart failure events that were generally mild. Kaplan-Meier curves showed higher rates of MACE in patients with higher NH-IMRangio (28.9% vs 13.3%; P = 0.019) and in those with 3 coronary arteries with increased MR compared to those with 2 or 1 affected arteries (33.3% vs 15.9% vs 9.5%; P = 0.040 and P = 0.040, respectively). After a multivariable Cox regression analysis, higher values of NH-IMRangio (HR: 3.41 [95% CI: 1.54-7.52]; P = 0.002) and the presence of 3 coronary arteries with increased MR (HR: 6.39 [95% CI: 1.46-27.87]; P = 0.014) were independent predictors of MACE in TTS patients., Conclusions: The degree and extent of an impaired MR assessed by a validated pressure-wire-free tool were independent predictors of MACE at 1-year follow-up in TTS patients., Competing Interests: Funding Support and Author Disclosures Dr García-García has received grants from Biotronik, Boston Scientific, Medtronic, Abbott, Neovasc, Shockwave, Phillips, and Corflow. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2022 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)