Postconditioning with Nitrates Protects Against Myocardial Reperfusion Injury: A New Use for an Old Pharmacological Agent

Cardioprotection in cardiovascular surgery

Since the invention of cardiopulmonary bypass, cardioprotective strategies have been investigated to mitigate ischemic injury to the heart during aortic cross-clamping and reperfusion injury with cross-clamp release. With advances in cardiac surgical and percutaneous techniques and post-operative management strategies including mechanical circulatory support, cardiac surgeons are able to operate on more complex patients. Therefore, there is a growing need for improved cardioprotective strategies to optimize outcomes in these patients. This review provides an overview of the basic principles of cardioprotection in the setting of cardiac surgery, including mechanisms of cardiac injury in the context of cardiopulmonary bypass, followed by a discussion of the specific approaches to optimizing cardioprotection in cardiac surgery, including refinements in cardiopulmonary bypass and cardioplegia, ischemic conditioning, use of specific anesthetic and pharmaceutical agents, and novel mechanical circulatory support technologies. Finally, translational strategies that investigate cardioprotection in the setting of cardiac surgery will be reviewed, with a focus on promising research in the areas of cell-based and gene therapy. Advances in this area will help cardiologists and cardiac surgeons mitigate myocardial ischemic injury, improve functional post-operative recovery, and optimize clinical outcomes in patients undergoing cardiac surgery.

Ischemic Postconditioning Attenuates Myocardial Ischemia-Reperfusion-Induced Acute Lung Injury by Regulating Endoplasmic Reticulum Stress-Mediated Apoptosis

OBJECTIVE

To explore the effect of ischemic postconditioning on myocardial ischemia-reperfusion-induced acute lung injury (ALI).

METHODS

Forty adult male C57BL/6 mice were randomly divided into sham operation group (SO group), myocardial ischemia-reperfusion group (IR group), ischemic preconditioning group (IPRE group) and ischemic postconditioning group (IPOST group) (10 mice in each group). Anterior descending coronary artery was blocked for 60 min and then reperfused for 15 min to induce myocardial IR. For the IPRE group, 3 consecutive cycles of 5 min of occlusion and 5 minutes of reperfusion of the coronary arteries were performed before ischemia. For the IPOST group, 3 consecutive cycles of 5 min reperfusion and 5 minutes of occlusion of the coronary arteries were performed before reperfusion. Pathological changes of lung tissue, lung wet-to-dry (W/D) weight ratio, inflammatory factors, oxidative stress indicators, apoptosis of lung cells and endoplasmic reticulum stress (ERS) protein were used to evaluate lung injury.

RESULTS

After myocardial IR, lung injury worsened significantly, manifested by alveolar congestion, hemorrhage, structural destruction of alveolar septal thickening, and interstitial neutrophil infiltration. In addition, lung W/D ratio was increased, plasma inflammatory factors, including interleukin (IL)-6, tumor necrosis factor (TNF)-α, and IL-17A, were increased, malondialdehyde (MDA) activity of lung tissue was increased, and superoxide dismutase (SOD) activity was decreased after myocardial IR. It was accompanied by the increased protein expression levels of ERS-related protein glucose regulatory protein 78 (GRP78), CCAAT/enhancer-binding protein (C/EBP) homologous protein (CHOP), and caspase-12, and the increased apoptotic indices of lung tissues.

CONCLUSION

IPOST can effectively improve myocardial IR-induced ALI by inhibiting ERS-induced apoptosis of alveolar epithelial cells.

Adverse Events Associated With Coprescription of Phosphodiesterase Type 5 Inhibitors and Oral Organic Nitrates in Male Patients With Ischemic Heart Disease : A Case-Crossover Study

BACKGROUND

Concomitant use of oral organic nitrates (nitrates) and phosphodiesterase type 5 (PDE5) inhibitors is contraindicated.

OBJECTIVE

To measure temporal trends in the coprescription of nitrates and PDE5 inhibitors and to measure the association between cardiovascular outcomes and the coprescription of nitrates with PDE5 inhibitors.

DESIGN

Case-crossover design.

SETTING

Nationwide study of Danish patients from 2000 to 2018.

PATIENTS

Male patients with International Classification of Diseases, 10th Revision (ICD-10) codes for ischemic heart disease (IHD), including those who had a continuing prescription for nitrates and a new, filled prescription for PDE5 inhibitors.

MEASUREMENTS

Two composite outcomes were measured: 1) cardiac arrest, shock, myocardial infarction, ischemic stroke, or acute coronary arteriography and 2) syncope, angina pectoris, or drug-related adverse event.

RESULTS

From 2000 to 2018, 249 541 male patients with IHD were identified. Of these, 42 073 patients had continuing prescriptions for nitrates. During this period, the prescription rate for PDE5 inhibitors in patients with IHD who were taking nitrates increased from an average of 0.9 prescriptions (95% CI, 0.5 to 1.2 prescriptions) per 100 persons per year in 2000 to 19.5 prescriptions (CI, 18.0 to 21.1 prescriptions) in 2018. No statistically significant association was found between the coprescription of nitrates with PDE5 inhibitors and the risk for either composite outcome (odds ratio [OR], 0.58 [CI, 0.28 to 1.13] for the first outcome and OR, 0.73 [CI, 0.40 to 1.32] for the second outcome).

LIMITATION

An assumption was made that concurrently filled prescriptions for nitrates and PDE5 inhibitors equaled concomitant use.

CONCLUSION

From 2000 to 2018, the use of PDE5 inhibitors increased 20-fold among Danish patients with IHD who were taking nitrates. A statistically significant association between concomitant use of these medications and cardiovascular adverse events could not be identified.

PRIMARY FUNDING SOURCE

Ib Mogens Kristiansens Almene Fond and Helsefonden.

Trend of Galectin-3 Levels in Patients with Non-ST-Elevation and ST-Elevation Myocardial Infarction

Background and Objectives: Given the fact that galectin-3 has a predictive significance on the development of myocardial dysfunction after acute myocardial infarction, the aim of our study was to examine potential factors that could be important for the dynamics of the concentration of this biomarker in the early postinfarction period. Materials and Methods: This study included 89 patients with a diagnosis of stable angina pectoris (SAP) or the first non-ST elevation (NSTEMI) or ST-elevation (STEMI) myocardial infarction, who underwent percutaneous coronary intervention (PCI). The study group included 23 patients with the first NSTEMI and 42 patients with STEMI, while the control group consisted of 24 patients with SAP hospitalized for elective PCI without a previous MI. All patients had preserved left ventricular ejection fraction. Galectin-3 levels were determined on days 1, 5, and 30 after PCI. The significance of various independent variables as predictors of galectin-3 concentration was analyzed after a series of univariate linear regression modeling in a multivariate linear regression model. Results: The average patients’ age was 63.99 ± 9.13 years. Statistically significantly higher values of C-reactive protein were established in STEMI compared to SAP (p < 0.01) or NSTEMI (p < 0.001), whereas WBC count was significantly lower in SAP than in STEMI (p < 0.001) and NSTEMI (p < 0.01) group. Although there were no statistically significant differences in measured galectin-3 concentrations between the examined groups on days 1, 5, and 30 after PCI, HTA, triglyceride level, LA size, treatment with trimetazidine and long-acting nitrates, as well as percentage of LM stenosis and E/A ratio were identified as independent predictors of galectin-3 concentration. Conclusions: In the post-MI period, very early values of galectin-3 correlate mostly with atherosclerosis factors, while on day 30 this biomarker correlates with diastolic dysfunction and “announces” left ventricular remodeling.