Cardioprotective and Antianginal Efficacy of Nicorandil: A Comprehensive Review

ABSTRACT

Angina pectoris remains a significant burden despite advances in medical therapy and coronary revascularization. Many patients (up to 30%) with angina have normal coronary arteries, with coronary microvascular disease and/or coronary artery vasospasm being major drivers of the myocardial demand-supply mismatch. Even among patients revascularized for symptomatic epicardial coronary stenosis, recurrent angina remains highly prevalent. Medical therapy for angina currently centers around 2 disparate goals, viz secondary prevention of hard clinical outcomes and symptom control. Vasodilators, such as nitrates, have been first-line antianginal agents for decades, along with beta-blockers and calcium channel blockers. However, efficacy in symptoms control is heterogenous, depending on underlying mechanism(s) of angina in an individual patient, often necessitating multiple agents. Nicorandil (NCO) is an antianginal agent first discovered in the late 1970s with a uniquely dual mechanism of action. Like a typical nitrate, it mediates medium-large vessel vasodilation through nitric oxide. In addition, NCO has adenosine triphosphate (ATP)-dependent potassium channel agonist activity (K ATP ), mediating microvascular dilatation. Hence, it has proven effective in both coronary artery vasospasm and coronary microvascular disease, typically challenging patient populations. Moreover, emerging evidence suggests that cardiomyocyte protection against ischemia through ischemic preconditioning may be mediated through K ATP agonism. Finally, there is now fairly firm evidence in favor of NCO in terms of hard event reduction among patients with stable coronary artery disease, following myocardial infarction, and perhaps even among patients with congestive heart failure. This review aims to summarize the mechanism of action of NCO, its efficacy as an antianginal, and current evidence behind its impact on hard outcomes. Finally, we review other cardiac and emerging noncardiac indications for NCO use.

A Rare Case of ST-Segment Elevation Myocardial Infarction and Left Ventricular Thrombus in a Dextrocardia Patient With COVID-19 Infection

Acute coronary syndrome (ACS) is an increasingly common finding among patients presenting with Coronavirus Disease 2019 (COVID-19) pneumonia. While cardiovascular disease alone remains one of the most common causes of death among COVID-19 patients in the United States, its heightened prevalence with COVID-19 pneumonia has been well documented. Here we present the case of a 58-year-old male with an extensive cardiac history including coronary artery disease (CAD) with multiple drug-eluting stents (DES) placed and an episode of cardiac arrest requiring implantable cardioverter defibrillator (ICD) placement. He presented to the Emergency Department originally complaining of chest pain, shortness of breath, and fatigue, and was found to be positive for COVID-19 pneumonia. Cardiac catheterization demonstrated extensive CAD and evaluation for coronary artery bypass grafting (CABG) was warranted. Shortly after, the patient experienced an acute thrombotic episode in the left anterior descending (LAD) coronary artery and underwent successful emergent high-risk percutaneous coronary intervention (PCI) with DES placement. The patient was also found to have a left ventricular thrombus requiring anticoagulation. Despite his complex course, the patient had a very favorable outcome.

Native valve emphysematous enterococcal endocarditis: expanding the differential diagnosis

INTRODUCTION

Emphysematous endocarditis is caused by the gas-forming organisms Citrobacter koseri, Escherichia coli, Clostridium species, and Finegoldia magna. We report the first case of emphysematous endocarditis caused by Enterococcus faecalis.

CASE REPORT

An 82-year-old man presented with fever and rapidly progressive shortness of breath. He was found to be in atrial fibrillation with rapid ventricular rates. Two-dimensional transthoracic echocardiography demonstrated severe mitral regurgitation. Subsequent two- and three-dimensional transesophageal echocardiogram revealed a large, highly mobile vegetation on the atrial surface of the anterior mitral leaflet with aneurysmal destruction of the lateral scallop requiring mitral valve replacement. Sequencing of the vegetation revealed Enterococcus faecalis, an anaerobic gram-positive coccus that, in rare cases, produces gas using a heme-dependent catalase. Histopathological analysis of the infected valve suggested interstitial gas accumulation, leading to the diagnosis of emphysematous endocarditis.

CONCLUSIONS

E. faecalis-associated emphysematous endocarditis should be included in the differential diagnosis of valvular vegetation in patients with a rapidly progressing clinical course. When possible, histopathological analysis should be used alongside other imaging techniques to confirm the diagnosis of emphysematous endocarditis. This case also highlights the importance of collecting blood cultures prior to initiating antibiotic treatment.

Frog sign and AV nodal reentrant tachycardia: A case report

Supraventricular tachycardia is one the most frequent cardiac arrhythmias seen in patients, with AVNRT being the most common subtype. Two subgroups of AVNRT have been reported, that of typical and atypical. “Frog Sign,” long considered a classic physical exam sign, albeit rare, is associated with typical AVNRT. We present a case of a patient who presented with frog sign and ultimately was determined to have AVNRT. Knowledge of “frog” sign aids clinical diagnosis and correct treatment.

Temporal Trend, Prevalence, Predictors, and Outcomes of Pericardial Diseases in Patients Undergoing Transcatheter Aortic Valve Repair

Background Pericardial disease (PD) - acute pericarditis (AP) and pericardial effusion (PE) - is a rare complication of transcatheter aortic valve repair (TAVR) although its prevalence, predictors, and outcomes are not well studied. Methods We used the National Inpatient Sample (NIS) database to find patients who received TAVR between 2011 and 2018. TAVR patients were divided into two groups: with and without PD (AP and/or PE). The baseline characteristics between the two groups were compared using the Chi-square test and student t-test. Variables with a p-value of 0.20 or less from the univariate logistic regression were included in the multivariate logistic regression to find independent predictors of PD in TAVR patients. Results Out of 218,340 TAVR hospitalizations, 4323 (1.2%) had a concurrent diagnosis of PD. TAVR patients with PD were older (81 ± 7 vs 80 ± 6 years, p < 0.05), more likely to be females (62 vs 46%, p < 0.001), white (84.2 vs 82.9%, p = 0.83), and had a higher burden of comorbidities (Table 3). TAVR patients with PD had higher in-hospital mortality rate (12.3 vs 1.9%, p < 0.001), mean length of stay (8.4 vs 5.3 days, p < 0.001), and mean total hospital cost ($283,389 vs $224,544, p < 0.001). Age > 75, female sex, atrial fibrillation (Afib), atrial flutter (Aflutter), peripheral vascular disease (PVD), coagulopathy, cirrhosis, malnutrition, percutaneous coronary intervention (PCI), coronary artery bypass grafting (CABG), and pacemaker (PM) implantation were the independent predictors of PD in TAVR patients. Conclusion Older, white females with a higher burden of comorbidities and cardiovascular procedures are at higher risk of pericardial complications of TAVR procedure. Sex-based disparities in the prevalence of PD after TAVR is an area of further research. Careful selection of patients for TAVR is essential to reduce the burden of these complications.