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Prompt referral for mechanical reperfusion by urgent primary percutaneous coronary intervention (PCI) represents a pivotal step in the current management of ST-segment elevation myocardial infarction (STEMI). 1 Yet, in a sizable proportion of patients, this intervention reopens the obstructed epicardial coronary artery but does not achieve myocardial reperfusion because of coronary microvascular obstruction. Several studies have clearly shown that coronary microvascular obstruction has a negative effect on outcome, negating the potential benefit of primary PCI. Indeed, such obstruction is associated with an increased prevalence of early postinfarction complications, adverse left ventricular remodeling, late repeat hospital stays for heart failure, and death. . . .

Endothelial erosion of atherosclerotic plaques is the underlying cause of approximately 30% of acute coronary syndromes (ACS). As the vascular endothelium is profoundly affected by the haemodynamic environment to which it is exposed, we employed computational fluid dynamic (CFD) analysis of the luminal geometry from 17 patients with optical coherence tomography (OCT)-defined plaque erosion, to determine the flow environment permissive for plaque erosion. Our results demonstrate that 15 of the 17 cases analysed occurred on stenotic plaques with median 31% diameter stenosis (interquartile range 28–52%), where all but one of the adherent thrombi located proximal to, or within the region of maximum stenosis. Consequently, all flow metrics related to elevated flow were significantly increased (time averaged wall shear stress, maximum wall shear stress, time averaged wall shear stress gradient) with a reduction in relative residence time, compared to a non-diseased reference segment. We also identified two cases that did not exhibit an elevation of flow, but occurred in a region exposed to elevated oscillatory flow. Our study demonstrates that the majority of OCT-defined erosions occur where the endothelium is exposed to elevated flow, a haemodynamic environment known to evoke a distinctive phenotypic response in endothelial cells.

Objective Cardiovascular (CV) outcome trials have shown that in patients with type 2 diabetes (T2D), treatment with sodium-glucose cotransporter-2 inhibitors (SGLT-2i) reduces CV mortality and hospital admission rates for heart failure (HF). However, the mechanisms behind these benefits are not fully understood. This study was performed to investigate the effects of the SGLT-2i dapagliflozin on myocardial perfusion and glucose metabolism in patients with T2D and stable coronary artery disease (coronary stenosis ≥ 30% and < 80%), with or without previous percutaneous coronary intervention (> 6 months) but no HF. Methods This was a single-center, prospective, randomized, double-blind, controlled clinical trial including 16 patients with T2D randomized to SGLT-2i dapagliflozin (10 mg daily) or placebo. The primary outcome was to detect changes in myocardial glucose uptake (MGU) from baseline to 4 weeks after treatment initiation by [(18)F]2-deoxy-2-fluoro-D-glucose (FDG) PET/CT during hyperinsulinemic euglycemic clamp. The main secondary outcome was to assess whether the hypothetical changes in MGU were associated with changes in myocardial blood flow (MBF) and myocardial flow reserve (MFR) measured by 13 N-ammonia PET/CT. The study was registered at eudract.ema.europa.eu (EudraCT No. 2016-003614-27) and ClinicalTrials.gov (NCT 03313752). Results 16 patients were randomized to dapagliflozin (n = 8) or placebo (n = 8). The groups were well-matched for baseline characteristics (age, diabetes duration, HbA1c, renal and heart function). There was no significant change in MGU during euglycemic hyperinsulinemic clamp in the dapagliflozin group (2.22 ± 0.59 vs 1.92 ± 0.42 μmol/100 g/min, p = 0.41) compared with the placebo group (2.00 ± 0.55 vs 1.60 ± 0.45 μmol/100 g/min, p = 0.5). Dapagliflozin significantly improved MFR (2.56 ± 0.26 vs 3.59 ± 0.35 p = 0.006 compared with the placebo group 2.34 ± 0.21 vs 2.38 ± 0.24 p = 0.81; p int  = 0.001) associated with a reduction in resting MBF corrected for cardiac workload (p = 0.005; p int  = 0.045). A trend toward an increase in stress MBF was also detected (p = 0.054). Conclusions SGLT-2 inhibition increases MFR in T2D patients. We provide new insight into SGLT-2i CV benefits, as our data show that patients on SGLT-2i are more resistant to the detrimental effects of obstructive coronary atherosclerosis due to increased MFR, probably caused by an improvement in coronary microvascular dysfunction. Trial registration EudraCT No. 2016-003614-27; ClinicalTrials.gov Identifier: NCT03313752

Patients with microvascular angina (MVA) often have persistence of symptoms despite full classical anti-ischemic therapy. In this study, we assessed the effect of ivabradine and ranolazine in MVA patients. We randomized 46 patients with stable MVA (effort angina, positive exercise stress test [EST], normal coronary angiography, coronary flow reserve <2.5), who had symptoms inadequately controlled by standard anti-ischemic therapy, to ivabradine (5 mg twice daily), ranolazine (375 mg twice daily), or placebo for 4 weeks. The Seattle Angina Questionnaire (SAQ), EuroQoL scale, and EST were assessed at baseline and after treatment. Coronary microvascular dilation in response to adenosine and to cold pressor test and peripheral endothelial function (by flow-mediated dilation) were also assessed. Both drugs improved SAQ items and EuroQoL scale compared with placebo (p <0.01 for all), with ranolazine showing some more significant effects compared with ivabradine, on some SAQ items and EuroQoL scale (p <0.05). Time to 1-mm ST-segment depression and EST duration were improved by ranolazine compared with placebo. No effects on coronary microvascular function and on flow-mediated dilation were observed with drugs or placebo. In conclusion, ranolazine and ivabradine may have a therapeutic role in MVA patients with inadequate control of symptoms in combination with usual anti-ischemic therapy.

Objective We recently demonstrated that treatment with sodium-glucose cotransporter-2 inhibitors (SGLT-2i) leads to an increase in myocardial flow reserve in patients with type 2 diabetes (T2D) with stable coronary artery disease (CAD). The mechanism by which this occurs is, however, unclear. One of the risk factors for cardiovascular disease is inflammation of epicardial adipose tissue (EAT). Since the latter is often increased in type 2 diabetes patients, it could play a role in coronary microvascular dysfunction. It is also well known that SGLT-2i modify adipose tissue metabolism. We aimed to investigate the effects of the SGLT-2i dapagliflozin on metabolism and visceral and subcutaneous adipose tissue thickness in T2D patients with stable coronary artery disease and to verify whether these changes could explain observed changes in myocardial flow. Methods We performed a single-center, prospective, randomized, double-blind, controlled clinical trial with 14 T2D patients randomized 1:1 to SGLT-2i dapagliflozin (10 mg daily) or placebo. The thickness of visceral (epicardial, mediastinal, perirenal) and subcutaneous adipose tissue and glucose uptake were assessed at baseline and 4 weeks after treatment initiation by 2-deoxy-2-[ 18 F]fluoro-D-glucose Positron Emission Tomography/Computed Tomography during hyperinsulinemic euglycemic clamp. Results The two groups were well-matched for baseline characteristics (age, diabetes duration, HbA1c, BMI, renal and heart function). Dapagliflozin treatment significantly reduced EAT thickness by 19% (p = 0.03). There was a significant 21.6% reduction in EAT glucose uptake during euglycemic hyperinsulinemic clamp in the dapagliflozin group compared with the placebo group (p = 0.014). There were no significant effects on adipose tissue thickness/metabolism in the other depots explored. Conclusions SGLT-2 inhibition selectively reduces EAT thickness and EAT glucose uptake in T2D patients, suggesting a reduction of EAT inflammation. This could explain the observed increase in myocardial flow reserve, providing new insights into SGLT-2i cardiovascular benefits.

Cardiovascular disease is the major cause of morbidity and mortality in breast cancer survivors. Chemotherapy contributes to this risk. We aimed to define the mechanisms of long-term vascular dysfunction caused by neoadjuvant chemotherapy (NACT) and identify novel therapeutic targets. We studied arteries from postmenopausal women who had undergone breast cancer treatment using docetaxel, doxorubicin, and cyclophosphamide (NACT) and from women with no history of such treatment matched for key clinical parameters. We explored mechanisms in WT and Nox4-/- mice and in human microvascular endothelial cells. Endothelium-dependent, NO-mediated vasodilatation was severely impaired in patients after NACT, while endothelium-independent responses remained normal. This was mimicked by a 24-hour exposure of arteries to NACT agents ex vivo. When applied individually, only docetaxel impaired endothelial function in human vessels. Mechanistic studies showed that NACT increased inhibitory eNOS phosphorylation of threonine 495 in a Rho-associated protein kinase-dependent (ROCK-dependent) manner and augmented vascular superoxide and hydrogen peroxide production and NADPH oxidase activity. Docetaxel increased expression of the NADPH oxidase NOX4 in endothelial and smooth muscle cells and NOX2 in the endothelium. A NOX4 increase in human arteries may be mediated epigenetically by diminished DNA methylation of the NOX4 promoter. Docetaxel induced endothelial dysfunction and hypertension in mice, and these were prevented in Nox4-/- mice and by pharmacological inhibition of Nox4 or Rock. Commonly used chemotherapeutic agents and, in particular, docetaxel alter vascular function by promoting the inhibitory phosphorylation of eNOS and enhancing ROS production by NADPH oxidases.

BackgroundCoronary vasomotor dysfunction represents an important mechanism responsible for myocardial ischaemia in patients with non-obstructive coronary artery disease (CAD). The use of invasive provocative tests allows identifying patients with epicardial or microvascular spasm. Of note, clinical characteristics associated with the occurrence of epicardial or microvascular spasm have still not completely clarified.Methods and resultsWe prospectively enrolled consecutive patients undergoing coronary angiography for suspected myocardial ischaemia/necrosis with evidence of non-obstructive CAD and undergoing intracoronary provocative test for suspected vasomotor dysfunction. Patients with a positive provocative test were enrolled. Clinical, echocardiographic and angiographic characteristics of patients were evaluated according to the pattern of vasomotor dysfunction (epicardial vs. microvascular spasm). We included 120 patients [68 patients with stable angina and 52 patients with myocardial infarction and non-obstructive coronary arteries (MINOCA)]. In particular, 77 (64.2%) patients had a provocative test positive for epicardial spasm and 43 (35.8%) patients for microvascular spasm. Patients with epicardial spasm were more frequently males, smokers, had higher rates of diffuse coronary atherosclerosis at angiography and more frequently presented with MINOCA. On the other hand, patients with microvascular spasm presented more frequently diastolic dysfunction. At multivariate logistic regression analysis male sex, smoking, and diffuse coronary atherosclerosis were independent predictors for the occurrence of epicardial spasm.ConclusionsOur study showed that specific clinical features are associated with different responses to intracoronary provocative test. Epicardial spasm is more frequent in males and in MINOCA patients, whereas microvascular spasm is more frequent in patients with stable angina and is associated with diastolic dysfunction.

ObjectiveLeft atrial (LA) and left ventricular (LV) mechanics are impaired in patients with atrial functional mitral regurgitation (AFMR), but their prognostic value in this subset of patients remains unknown. The present study aimed to evaluate the association between LA and LV longitudinal strain and clinical outcomes in patients with AFMR.MethodsA total of 197 patients (mean age 73±10 years, 44% men) with at least moderate AFMR were retrospectively identified. LV global longitudinal strain (GLS) and left atrial reservoir strain (LAS) were calculated by two-dimensional speckle tracking echocardiography. All-cause mortality was the primary endpoint of the study. The threshold value of LV GLS (≤16.3%) to identify impaired LV mechanics was defined based on the risk excess of the primary endpoint described with a spline curve analysis.ResultsImpaired LV GLS (≤16.3%) was found in 89 (45%) patients. During a median follow-up of 69 months, 45 (23%) subjects experienced the primary endpoint. Patients with impaired LV GLS (≤16.3%) had a significantly lower cumulative survival rate at 5 years, as compared with patients with LV GLS (>16.3%) (74% vs 93%, p<0.001). On multivariable Cox regression analysis, LV GLS expressed as continuous variable was independently associated with the occurrence of all-cause mortality (HR 0.856, 95% CI 0.763 to 0.960; p=0.008) after adjustment for age, LAS, pulmonary artery systolic pressure and severe tricuspid regurgitation. Conversely, LAS was not significantly associated with patients’ outcome.ConclusionsIn patients with significant AFMR, the impairment of LV GLS was independently associated with worse outcomes.

Percutaneous coronary intervention (PCI) is considered a relatively safe procedure associated with low rates of complications, but is inevitably associated with short and mid-to-long term increased bleeding risk. Besides the short term risk associated with the arterial access to perform PCI, enhanced bleeding risk persists for several months, given the need for antithrombotic therapy to prevent procedure-related thrombotic complications as well as ischemic recurrences. Bleeding is a powerful harbinger of adverse outcomes. This awareness has fuelled intense research on bleeding reduction strategies, including new PCI devices and techniques as well as new medications and antithrombotic regimens. We here review the mechanisms and prevalence of bleeding in PCI patients, discuss the available evidence from a practical point of view, and explore future perspectives on how to treat and prevent bleeding complications in these patients.

PLIN2 is involved in the lipid metabolism of macrophages resident in atherosclerotic plaques, and its upregulation leads to lipid droplets (LDs) accumulation. LDs enlargement results in the macrophage transformation into foam cells, a key step for the onset of atherosclerosis. In the present study, we investigated the role of PLIN2 and its regulation mechanisms in atherosclerosis and plaque instability in patients with a diagnosis of ST-elevation myocardial infarction (STEMI) and chronic coronary syndrome (CCS). We enrolled STEMI (n = 122) and CCS patients (n = 45). Peripheral blood mononuclear cells were isolated from whole blood samples. The PLIN2 protein level was analyzed in CD14+ monocytes by flow cytometry. Lipidomic panel and proteasome activity were evaluated. PLIN2 protein expression was significantly correlated with the age of CAD patients. We found no significant difference in monocyte lipid content between the two patient groups. The PLIN2 increased in STEMI as compared to CCS patients (p < 0.001). The proteasome activity being higher in STEMI as compared to CCS patients (p < 0.001), significant inverse correlations were evident between PLIN2 levels and proteasome activity in the CCS groups (p = 0.02). PLIN2 expression was higher in STEMI as compared to CCS patients, suggesting an involvement in plaque instability. Despite the proteasome activity being higher in STEMI patients, probably due to the elevated inflammatory burden, PLIN2 could escape proteasome degradation in a more efficient manner in STEMI as compared to CCS patients.