Background A relevant proportion of patients with suspected coronary artery disease undergo invasive coronary angiography showing normal or nonobstructive coronary arteries. However, the prevalence of coronary microvascular disease (CMD) and coronary spasm in patients with nonobstructive coronary artery disease remains to be determined. The objective of this study was to determine the prevalence of coronary CMD and coronary vasospastic angina in patients with no obstructive coronary artery disease. Methods and Results A systematic review and meta‐analysis of studies assessing the prevalence of CMD and vasospastic angina in patients with no obstructive coronary artery disease was performed. Random‐effects models were used to determine the prevalence of these 2 disease entities. Fifty‐six studies comprising 14 427 patients were included. The pooled prevalence of CMD was 0.41 (95% CI, 0.36–0.47), epicardial vasospasm 0.40 (95% CI, 0.34–0.46) and microvascular spasm 24% (95% CI, 0.21–0.28). The prevalence of combined CMD and vasospastic angina was 0.23 (95% CI, 0.17–0.31). Female patients had a higher risk of presenting with CMD compared with male patients (risk ratio, 1.45 [95% CI, 1.11–1.90]). CMD prevalence was similar when assessed using noninvasive or invasive diagnostic methods. Conclusions In patients with no obstructive coronary artery disease, approximately half of the cases were reported to have CMD and/or coronary spasm. CMD was more prevalent among female patients. Greater awareness among physicians of ischemia with no obstructive coronary arteries is urgently needed for accurate diagnosis and patient‐tailored management.

Background The glucose-lowering independent effect of sodium glucose cotransporter-2 inhibitors (SGLT2i) on arterial wall function has not yet been clarified. This study aims to assess whether SGLT2i treatment can attenuate endothelial dysfunction related to type 2 diabetes mellitus (T2D) compared with glucose-lowering equivalent therapy. Methods In a prospective, open-label, single-center, randomized clinical trial, 98 patients with T2DM and carotid intima-media thickness above the 75th percentile were randomized 1:1 to 12 weeks of therapy with dapagliflozin or glibenclamide in addition to metformin in glucose-lowering equivalent regimens. The coprimary endpoints were 1-min flow-mediated dilation (FMD) at rest and 1-min FMD after 15 min of ischemia followed by 15 min of reperfusion time (I/R). Results Ninety-seven patients (61% males, 57 ± 7 years) completed the study. The median HbA1c decreased by − 0.8 (0.7)% and -0.7 (0.95)% following dapagliflozin and glibenclamide, respectively. The first coprimary endpoint, i.e., rest FMD changed by + 3.3(8.2)% and − 1.2(7.5)% for the dapagliflozin and glibenclamide arms, respectively (p = 0.0001). Differences between study arms in the second coprimary endpoint were not significant. Plasma nitrite 1 min after rest FMD was higher for dapagliflozin [308(220) nmol/L] than for glibenclamide (258[110] nmol/L; p = 0.028). The resistive indices at 1 min [0.90 (0.11) vs. 0.93 (0.07); p = 0.03] and 5 min [0.93 (0.07) vs. 0.95 (0.05); p = 0.02] were higher for the glibenclamide group than for the dapagliflozin group. Plasma biomarkers for inflammation and oxidative stress did not differ between the treatments. Conclusions Dapagliflozin improved micro- and macrovascular endothelial function compared to glibenclamide, regardless of glycemic control in patients with T2DM and subclinical carotid atherosclerotic disease.

Background: Coronary microvascular dysfunction (CMD) is an early feature of diabetic cardiomyopathy, which usually precedes the onset of diastolic and systolic dysfunction. Continuous intracoronary thermodilution allows an accurate and reproducible assessment of absolute coronary blood flow and microvascular resistance thus allowing the evaluation of coronary flow reserve (CFR) and Microvascular Resistance Reserve (MRR), a novel index specific for microvascular function, which is independent from the myocardial mass. In the present study we compared absolute coronary flow and resistance, CFR and MRR assessed by continuous intracoronary thermodilution in diabetic vs. non-diabetic patients. Left atrial reservoir strain (LASr), an early marker of diastolic dysfunction was compared between the two groups.Methods: In this observational retrospective study, 108 patients with suspected angina and non-obstructive coronary artery disease (NOCAD) consecutively undergoing elective coronary angiography (CAG) from September 2018 to June 2021 were enrolled. The invasive functional assessment of microvascular function was performed in the left anterior descending artery (LAD) with intracoronary continuous thermodilution. Patients were classified according to the presence of DM. Absolute resting and hyperemic coronary blood flow (in mL/min) and resistance (in WU) were compared between the two cohorts. FFR was measured to assess coronary epicardial lesions, while CFR and MRR were calculated to assess microvascular function. LAS, assessed by speckle tracking echocardiography, was used to detect early myocardial structural changes potentially associated with microvascular dysfunction.Results: The median FFR value was 0.83 [0.79–0.87] without any significant difference between the two groups. Absolute resting and hyperemic flow in the left anterior descending coronary were similar between diabetic and non-diabetic patients. Similarly, resting and hyperemic resistances did not change significantly between the two groups. In the DM cohort the CFR and MRR were significantly lower compared to the control group (CFR = 2.38 ± 0.61 and 2.88 ± 0.82; MRR = 2.79 ± 0.87 and 3.48 ± 1.02 for diabetic and non-diabetic patients respectively, [p < 0.05 for both]). Likewise, diabetic patients had a significantly lower reservoir, contractile and conductive LAS (all p < 0.05).Conclusions: Compared with non-diabetic patients, CFR and MRR were lower in patients with DM and non-obstructive epicardial coronary arteries, while both resting and hyperemic coronary flow and resistance were similar. LASr was lower in diabetic patients, confirming the presence of a subclinical diastolic dysfunction associated to the microcirculatory impairment. Continuous intracoronary thermodilution-derived indexes provide a reliable and operator-independent assessment of coronary macro- and microvasculature and might potentially facilitate widespread clinical adoption of invasive physiologic assessment of suspected microvascular disease.