Cardiac microRNAs: diagnostic and therapeutic potential.

MicroRNAs are small non-coding post-translational biomolecules which, when expressed, modify their target genes. It is estimated that microRNAs regulate production of approximately 60% of all human proteins and enzymes that are responsible for major physiological processes. In cardiovascular disease pathophysiology, there are several cells that produce microRNAs, including endothelial cells, vascular smooth muscle cells, macrophages, platelets, and cardiomyocytes. There is a constant crosstalk between microRNAs derived from various cell sources. Atherosclerosis initiation and progression are driven by many pro-inflammatory and pro-thrombotic microRNAs. Atherosclerotic plaque rupture is the leading cause of cardiovascular death resulting from acute coronary syndrome (ACS) and leads to cardiac remodeling and fibrosis following ACS. MicroRNAs are powerful modulators of plaque progression and transformation into a vulnerable state, which can eventually lead to plaque rupture. There is a growing body of evidence which demonstrates that following ACS, microRNAs might inhibit fibroblast proliferation and scarring, as well as harmful apoptosis of cardiomyocytes, and stimulate fibroblast reprogramming into induced cardiac progenitor cells. In this review, we focus on the role of cardiomyocyte-derived and cardiac fibroblast-derived microRNAs that are involved in the regulation of genes associated with cardiomyocyte and fibroblast function and in atherosclerosis-related cardiac ischemia. Understanding their mechanisms may lead to the development of microRNA cocktails that can potentially be used in regenerative cardiology.

Prognostic Factors in Patients with Sudden Cardiac Arrest and Acute Myocardial Infarction Undergoing Percutaneous Interventions with the LUCAS-2 System for Mechanical Cardiopulmonary Resuscitation.

Sudden cardiac arrest (SCA) is one of the most perilous complications of acute myocardial infarction (AMI). For years, the return of spontaneous circulation (ROSC) has had to be achieved before the patient could be treated at the catheterization laboratory, as simultaneous manual chest compression and angiography were mutually exclusive. Mechanical chest compression devices enabled simultaneous resuscitation and invasive percutaneous procedures. The aim was to characterize the poorer responders that would allow one to predict the positive outcome of such a treatment. We retrospectively analyzed the medical charts of 94 patients with SCA due to AMI, who underwent mechanical cardiopulmonary resuscitation during angiography. In total, 48 patients, 8 (17%) of which survived the event, were included in the final analysis, which revealed that 83% of the survivors had mild to moderate hyperkalemia (potassium 5.0−6.0 mmol/L), in comparison to 15% of non-survivors (p = 0.002). In the age- and sex-adjusted model, patients with serum potassium > 5.0 mmol/L had 4.61-times higher odds of survival until discharge from the hospital (95% CI: 1.41−15.05, p = 0.01). Using the highest Youden index, we identified the potassium concentration of 5.1 mmol/L to be the optimal cut-off value for prediction of survival until hospital discharge (83.3% sensitivity and 87.9% specificity). The practical implications of these findings are that patients with potassium levels between 5.0 and 6.0 mmol/L may actually benefit most from percutaneous coronary interventions with ongoing mechanical chest compressions and that they do not need immediate correction for this electrolyte abnormality.

Balloon aortic valvuloplasty for severe aortic stenosis may reduce mitral regurgitation in mid-term follow-up.

Introduction: Mitral regurgitation (MR) is a frequent complication in patients with severe aortic stenosis (AS). Material and methods: Echocardiographic assessment of MR was performed at baseline, at 30 days and at 6 months after balloon aortic valvuloplasty (BAV). Results: Data of 271 patients were included in our final analysis, of which 21.2% (n = 85) had at least moderate MR at baseline (in 19 (22.3%) subjects MR was diagnosed as primary). Both groups showed similar severity of AS, but patients in the MR group had a greater left ventricle (LV) size (p = 0.003 for LVESD, p = 0002 for LVEDD) and slightly lower LV ejection fraction (p = 0.04). Mitral regurgitation parameters significantly improved both at 30 days and 6 months after BAV in the MR group (MR jet area: 7.2 (4.5-9.9) vs. 3.6 (2.3-7.2) cm2, and 7.2 (4.5-9.9) vs. 3.2 (2.1-6.7) cm2; %MR/left atrial area 34.5 (23.4-42.7) vs. 17.5 (9.3-29.5) and 34.5 (23.4-42.7) vs. 14.5 (8.3-24.5), p < 0.001 for all). In multivariate logistic regression analysis, the change at 30 days, from baseline, in the LVESD (OR = 1.87; 95% CI: 1.23-2.87; p < 0.001) and LVEF (OR = 0.95; 95% CI: 0.87-1.01; p < 0.001); MR jet area (OR = 2.2, 95% CI: 1.5-4.6; p < 0.001) and the presence of primary MR (OR = 3.2, 95% CI: 1.04-5.98; p < 0.001) were retained as independent predictors of significant persisting MR at 6 months. Conclusions: Balloon aortic valvuloplasty may reduce MR in mid-term follow-up. Predictors of persistent MR at 6 months after BAV included an increase of LVESD and MR jet area and decrease of LVEF at 30 days.

Low Ejection Fraction Predisposes to Contrast-Induced Nephropathy after the Second Step of Staged Coronary Revascularization for Acute Myocardial Infarction: A Retrospective Observational Study.

Patients who develop contrast-induced nephropathy (CIN) are at an increased short-term and long-term risk of adverse cardiovascular (CV) events. Our aim was to search for patient characteristics associated with changes in serum creatinine and CIN incidence after each step of two-stage coronary revascularization in patients with acute myocardial infarction (AMI) and multivessel coronary artery disease undergoing staged coronary angioplasty during hospitalization for AMI. We retrospectively analyzed medical records of 138 patients with acute myocardial infarction without hemodynamic instability, in whom two-stage coronary angioplasty was performed during the initial hospital stay. In-hospital serum creatinine levels were recorded before the 1st intervention (at admission), within 72 h after the 1st intervention (before the 2nd intervention), and within 72 h after the 2nd intervention. The incidence of CIN was 2% after the 1st intervention (i.e., primary angioplasty) and 8% after the 2nd intervention. Patients with significant left ventricular systolic dysfunction after the 1st intervention (ejection fraction (EF) ≤35%) exhibited higher relative rises in creatinine levels after the 2nd intervention (18 ± 29% vs. 2 ± 16% for EF ≤35% and >35%, respectively, p = 0.03), while respective creatinine changes after the 1st revascularization procedure were comparable (-1 ± 14% vs. 2 ± 13%, p = 0.4). CIN after the 2nd intervention was over five-fold more frequent in subjects with low EF (28% vs. 5%, p = 0.007). The association between low EF and CIN incidence or relative creatinine changes after the 2nd intervention was maintained upon adjustment for baseline renal function, major CV risk factors, and the use of renin-angiotensin axis antagonists prior to admission. In conclusion, low EF predisposes to CIN after second contrast exposure in patients undergoing two-stage coronary angioplasty during the initial hospitalization for AMI. Our findings suggest a need of extended preventive measures against CIN or even postponement of second coronary intervention in patients with significant left ventricular dysfunction scheduled for the second step of staged angioplasty.