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Echocardiographic evaluation is an essential part of the diagnostic work-up in patients with known or suspected cardiovascular disease. Transthoracic Doppler echocardiography (TTDE) enables straightforward and reliable visualization of flow in the left anterior descending artery. In the absence of obstructive coronary artery disease, low TTDE-derived coronary flow velocity reserve (CFVR) is considered a marker of coronary microvascular dysfunction (CMD). TTDE CFVR is free from ionizing radiation and widely available, utilizing high-frequency transducers, pharmacologic vasodilator stress, and pulsed-wave Doppler quantification of diastolic peak flow velocities. European Society of Cardiology guidelines recommend TTDE CFVR evaluation only following preceding anatomic invasive or non-invasive coronary imaging excluding obstructive CAD. Accordingly, clinical use of TTDE CFVR is limited and CMD frequently goes undiagnosed. An evolving body of evidence underlines that low CFVR is an important and robust predictor of adverse prognosis and continuing symptoms in angina patients both with and without obstructive CAD. The majority of angina patients have no obstructive CAD, particularly among women. This has led to the suggestion that there may be a gender-specific female atherosclerotic phenotype with less epicardial obstruction, and a low CFVR signifying CMD instead. Nevertheless, available evidence indicates low CFVR is an equally important prognostic marker in both men and women. In this review, TTDE CFVR was evaluated regarding indication, practical and technical aspects, and interpretation of results. Association with symptoms and prognosis, comparison with alternative invasive and non-invasive imaging modalities, and possible interventions in angina patients with low CFVR were discussed, and key research questions were proposed.

Aims Many patients with angina, especially women, do not have obstructive coronary artery disease (CAD) yet have impaired prognosis. We investigated whether routine assessment of coronary microvascular dysfunction (CMD) is feasible and predicts adverse outcome in women with angina and no obstructive CAD. Methods and results After screening 7253, we included 1853 women with angina and no obstructive CAD on angiogram who were free of previous CAD, heart failure, or valvular heart disease in the prospective iPOWER (Improving Diagnosis and Treatment of Women with Angina Pectoris and Microvascular Disease) study. CMD was assessed by Doppler echocardiography in the left anterior descending artery as coronary flow velocity reserve (CFVR). Patients were followed for a composite outcome of cardiovascular death, myocardial infarction (MI), heart failure, stroke, and coronary revascularization. CFVR was obtained in 1681 patients (91%) and the median CFVR was 2.33 (quartiles 1–3: 2.00–2.74). During a median follow-up of 4.5 years, 96 events occurred. In univariate Cox regression, CFVR was associated with the composite outcome {hazard ratio (HR) 1.07 [95% confidence interval (CI) 1.03–1.11] per 0.1 unit decrease in CFVR; P Conclusion Assessment of CFVR by echocardiography is feasible and predictive of adverse outcome in women with angina and no obstructive CAD. Results support a more aggressive preventive management of these patients and underline the need for trials targeting CMD.

ObjectivesCoronary microvascular dysfunction (CMD) is considered to cause angina pectoris in a large proportion of women with no obstructive coronary artery disease (CAD). However, data supporting a relation between angina pectoris and CMD are limited. We compared CMD in women with angina with asymptomatic women and evaluated the relation between presence of CMD, angina characteristics, cardiovascular risk factors and results of stress testing.MethodsIn a cross-sectional study, we included 1684 women with angina and ResultsMedian CFVR was 2.33 (IQR 2.00–2.75) in symptomatic women versus 2.60 (2.19–2.95) in asymptomatic (p=0.007). CFVR ConclusionsImpaired CFVR is more prevalent in symptomatic than in asymptomatic women and related to the cardiovascular risk factors hypertension, diabetes, smoking and increased heart rate. Neither a positive bicycle test, single photon emission CT stress test nor chest pain characteristics identify women with impaired CFVR among women with angina and no obstructive CAD. Results may question the concept of microvascular angina as currently defined.

Background The inflammatory biomarker YKL‐40 has previously been studied as a potential risk marker in cardiovascular disease. We aimed to assess the prognostic reclassification potential of serum YKL‐40 in patients with stable coronary artery disease. Methods and Results The main study population was the placebo group of the CLARICOR (Effect of Clarithromycin on Mortality and Morbidity in Patients With Ischemic Heart Disease) trial. The primary outcome was a composite of acute myocardial infarction, unstable angina pectoris, cerebrovascular disease, and all‐cause mortality. We used Cox proportional hazards regression models adjusted for C‐reactive protein level and baseline cardiovascular risk factors. Improvement in prediction by adding serum YKL‐40 to the risk factors was calculated using the Cox‐Breslow method and c‐statistic. A total of 2200 patients were randomized to placebo, with a follow‐up duration of 10 years. YKL‐40 was associated with an increased risk of the composite outcome (hazard ratio per unit increase in (YKL‐40) 1.13, 95% CI 1.03–1.24, P =0.013) and all‐cause mortality (hazard ratio 1.32, 95% CI 1.17–1.49, P Conclusions Higher serum YKL‐40 was independently associated with an increased risk of adverse cardiovascular outcomes and mortality. Addition of YKL‐40 did not improve risk prediction in patients with stable coronary artery disease. Clinical Trial Registration URL: https://www.clinicaltrials.gov/ . Unique identifier: NCT00121550.

Background It has been proposed that multiple comorbidities including diabetes, hypertension and dyslipidemia contribute to a pro-inflammatory state that induces oxidative stress in the microvascular endothelium, leading to coronary microvascular dysfunction (CMD) and cardiac diastolic dysfunction. Purpose We tested the hypothesis that subclinical inflammation is an underlying cause of both CMD and diastolic dysfunction and that the effect of inflammation on diastolic function is partly mediated by CMD. Methods In a cross-sectional study design, we included women with angina but no flow limiting coronary artery stenosis (180 with diabetes, 156 without diabetes) and 95 asymptomatic controls. Blood samples were analysed for 91 mainly inflammatory cardiovascular biomarkers. Coronary microvascular function was assessed as coronary flow velocity reserve (CFVR) by transthoracic Doppler echocardiography. Correlation of each biomarker with CFVR and E/e' as a marker of diastolic function, was examined by age adjusted linear regression and mediation analysis was conducted to assess if any effect of inflammation on E/e' was mediated by impaired CFVR. Results CFVR was lowest in patients with diabetes and highest in controls and, conversely, E/e' was highest in patients with diabetes (both test for trend p Population charachteristics compared across groups with trend test (unadjusted linear regression) Diabetes (n=180) No diabetes (n=156) Control (n=95) p for trend Age, mean (min, max) 64 (36,80) 62 (32,80) 61 (32,81)* 0.003 BMI, mean (min, max) 30.7 (15.2, 45.5) 26.1 (18.6,40.0)* 24.7 (18.6,38.4)* Generic directed acyclic graph Conclusion This is the first study to link a large number of mainly inflammatory biomarkers to CMD and diastolic dysfunction in patients suspected of microvascular angina. Direct association between CMD and diastolic function was only seen in those with impaired CFVR and poorest diastolic function. Acknowledgement/Funding The Danish Council for Independent Research and the Danish Heart Foundation

Background: Studies that evaluate larger numbers of protein biomarkers in patients with coronary microvascular dysfunction (CMD) have not previously been performed, and very little is known concerning the pathogenetic mechanisms leading to CMD.Our objective was to analyze associations between a broad cardiovascular disease (CVD) protein biomarker assay and CMD, and further explore internal biomarker relations in order to identify possible targets for future treatment interventions. Methods: In 174 women with angina pectoris and no significant obstructive coronary artery disease (