Coronary Adventitial and Perivascular Adipose Tissue Inflammation in Patients With Vasospastic Angina

BACKGROUND

Recent studies suggested that perivascular components, such as perivascular adipose tissue (PVAT) and adventitial vasa vasorum (VV), play an important role as a source of various inflammatory mediators in cardiovascular disease.

OBJECTIVES

The authors tested their hypothesis that coronary artery spasm is associated with perivascular inflammation in patients with vasospastic angina (VSA) using ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT).

METHODS

This study prospectively examined 27 consecutive VSA patients with acetylcholine-induced diffuse spasm in the left anterior descending artery (LAD) and 13 subjects with suspected angina but without organic coronary lesions or coronary spasm. Using CT coronary angiography and electrocardiogram-gated ¹⁸F-FDG PET/CT, coronary PVAT volume and coronary perivascular FDG uptake in the LAD were examined. In addition, adventitial VV formation in the LAD was examined with optical coherence tomography, and Rho-kinase activity was measured in circulating leukocytes.

RESULTS

Patient characteristics were comparable between the 2 groups. CT coronary angiography and ECG-gated ¹⁸F-FDG PET/CT showed that coronary PVAT volume and coronary perivascular FDG uptake significantly increased in the VSA group compared with the non-VSA group. Furthermore, optical coherence tomography showed that adventitial VV formation significantly increased in the VSA group compared with the non-VSA group, as did Rho-kinase activity. Importantly, during the follow-up period with medical treatment, both coronary perivascular FDG uptake and Rho-kinase activity significantly decreased in the VSA group.

CONCLUSIONS

These results provide the first evidence that coronary spasm is associated with inflammation of coronary adventitia and PVAT, where ¹⁸F-FDG PET/CT could be useful for disease activity assessment. (Morphological and Functional Change of Coronary Perivascular Adipose Tissue in Vasospastic Angina [ADIPO-VSA Trial]; UMIN000016675).

Advances in small-molecule therapy for managing angina pectoris in the elderly

Introduction: As our population ages, the prevalence of angina is growing, leading to increased morbidity and decreased quality of life. The management of angina in the elderly is challenging due to drug intolerance and/or drug resistance as well as frailty. Over the past decades, many new therapeutic small molecules have been investigated for the management of angina. Although none of these studies have specifically focused on the therapies for the elderly, they offer promising new avenues for the treatment of angina in the elderly. Areas covered: Herein, the authors provide a review of the recently published literature on the use of small-molecule therapies for angina management in the elderly and provide a brief overview of these therapies. Expert opinion: A variety of therapeutic classes of existing and newer small molecules are emerging for the management of angina in the elderly. An individualized approach to the management of angina in this growing population is critical for good outcomes. Many small molecules are in their initial stages of clinical use, and further research should be conducted on their utility, especially in the elderly.

Association of East Asian Variant Aldehyde Dehydrogenase 2 Genotype (ALDH2*2*) with Coronary Spasm and Acute Myocardial Infarction

Coronary spasm plays an important role in the pathogenesis of ischemic heart disease, including angina pectoris, acute myocardial infarction (AMI), silent myocardial ischemia, and sudden death. The prevalence of coronary spasm is higher among East Asians probably due to genetic as well as environmental factors. ALDH2 eliminates toxic aldehydes including 4-hydroxy-2-nonenal (4-HNE) derived from lipid peroxidation and acrolein in tobacco smoking as well as ethanol-derived acetaldehyde and thereby protects tissues and cells from oxidative damage. Deficient variant ALDH2*2 genotype is prevalent among East Asians and is a significant risk factor for both coronary spasm and AMI through accumulation of toxic aldehydes, thereby contributing to oxidative stress, endothelial damage, vasoconstriction, and thrombosis. Toxic aldehydes are thus identified as risk factors to be targeted for the treatment of coronary spasm and AMI.

Coronary artery spasm - Clinical features, pathogenesis and treatment

Coronary artery spasm (CAS) plays an important role in the pathogenesis of ischemic heart disease, including angina pectoris, myocardial infarction, and sudden death, occurring most often from midnight to early morning. CAS is prevalent among East Asians and is associated with an aldehyde dehydrogenase 2 (ALDH2)-deficient genotype (ALDH2*2) and alcohol flushing, which is prevalent among East Asians but is virtually non-existent in other populations. ALDH2 eliminates not only acetaldehyde but also other toxic aldehydes from lipid peroxidation and tobacco smoking, thereby protecting tissues and cells from oxidative damage. Risk factors for CAS include smoking and genetic polymorphisms including those of ALDH2*2, endothelial NO synthase, paraoxonase I, and interleukin-6. Accordingly, oxidative stress, endothelial dysfunction, and low-grade chronic inflammation play an important role in the pathogenesis of CAS, leading to increased coronary smooth muscle Ca²⁺ sensitivity through RhoA/ROCK activation and resultant hypercontraction. Ca-channel blockers blocking the intracellular entry of Ca²⁺ are specifically effective for treatment for CAS.

Impact of different nitrate therapies on long-term clinical outcomes of patients with vasospastic angina: A propensity score-matched analysis

BACKGROUND

Despite the short-term vasodilatory effects of nitrates, the prognostic effects of long-term nitrate therapy in patients with vasospastic angina (VSA) remains unclear. We investigated the prognostic impact of chronic nitrate therapy in VSA patients.

METHODS

Between January 2003 and December 2014, a total of 1154 VSA patients proven by ergonovine provocation tests were classified into nitrate (n=676) and non-nitrate (n=478) groups according to prescriptions for oral nitrates, including isosorbide mononitrate (ISMN) and nicorandil. The primary outcome was major adverse cardiovascular events (MACE), defined as a composite of cardiac death, myocardial infarction, any revascularization, or rehospitalization due to recurrent angina.

RESULTS

The nitrate group was found to have a higher risk of MACE (22.9% vs. 17.6%, hazard ratio [HR] 1.32, 95% confidence interval [CI] 1.01-1.73, p=0.043) than the non-nitrate group. After propensity score matching, the nitrate group had greater risks of MACE (HR 1.32, 95%CI 1.01-1.73, p=0.049). Patients who received the immediate-release formula of ISMN (HR 1.80, 95%CI 1.35-2.39, p<0.001) or were administered any forms of ISMN other than at bedtime (HR 1.90, 95%CI 1.41-2.57, p<0.001) had a significantly higher risk of MACE compared with the non-nitrate group. Nicorandil was shown to have a neutral effect on VSA patients (HR 1.11, 95%CI 0.73-1.69, p=0.62).

CONCLUSIONS

The long-term use of nitrate therapy was associated with increased risk of adverse cardiac events in VSA patients. The use of immediate-release ISMN or the administration of ISMN other than at bedtime was related with poor outcomes of VSA patients.

Nicorandil and Long-acting Nitrates: Vasodilator Therapies for the Management of Chronic Stable Angina Pectoris

Nicorandil and long-acting nitrates are vasodilatory drugs used commonly in the management of chronic stable angina pectoris. Both nicorandil and long-acting nitrates exert anti-angina properties via activation of nitric oxide (NO) signalling pathways, triggering vascular smooth muscle cell relaxation. Nicorandil has additional actions as an arterial K⁺ _ATP channel agonist, resulting in more "balanced" arterial and venous vasodilatation than nitrates. Ultimately, these drugs prevent angina symptoms through reductions in preload and diastolic wall tension and, to a lesser extent, epicardial coronary artery dilatation and lowering of systemic blood pressure. While there is some evidence to suggest a modest reduction in cardiovascular events among patients with stable angina treated with nicorandil compared to placebo, this prognostic benefit has yet to be proven conclusively. In contrast, there is emerging evidence to suggest that chronic use of long-acting nitrates might cause endothelial dysfunction and increased cardiovascular risk in some patients.

Prognosis of Variant Angina Manifesting as Aborted Sudden Cardiac Death

BACKGROUND

The long-term prognosis of patients with variant angina presenting with aborted sudden cardiac death (ASCD) is unknown.

OBJECTIVES

The purpose of this study was to evaluate the long-term mortality and ventricular tachyarrhythmic events of variant angina with and without ASCD.

METHODS

Between March 1996 and September 2014, 188 patients with variant angina with ASCD and 1,844 patients with variant angina without ASCD were retrospectively enrolled from 13 heart centers in South Korea. The primary endpoint was cardiac death.

RESULTS

Predictors of ASCD manifestation included age (odd ratio [OR]: 0.980 by 1 year increase; 95% confidence interval [CI]: 0.96 to 1.00; p = 0.013), hypertension (OR: 0.51; 95% CI: 0.37 to 0.70; p < 0.001), hyperlipidemia (OR: 0.38; 95% CI: 0.25 to 0.58; p < 0.001), family history of sudden cardiac death (OR: 3.67; 95% CI: 1.27 to 10.6; p = 0.016), multivessel spasm (OR: 2.06; 95% CI: 1.33 to 3.19; p = 0.001), and left anterior descending artery spasm (OR: 1.40; 95% CI: 1.02 to 1.92; p = 0.04). Over a median follow-up of 7.5 years, the incidence of cardiac death was significantly higher in ASCD patients (24.1 per 1,000 patient-years vs. 2.7 per 1,000 patient-years; adjusted hazard ratio [HR]: 7.26; 95% CI: 4.21 to 12.5; p < 0.001). Death from any cause also occurred more frequently in ASCD patients (27.5 per 1,000 patient-years vs. 9.6 per 1,000 patient-years; adjusted HR: 3.00; 95% CI: 1.92 to 4.67; p < 0.001). The incidence rate of recurrent ventricular tachyarrhythmia in ASCD patients was 32.4 per 1,000 patient-years, and the composite of cardiac death and ventricular tachyarrhythmia was 44.9 per 1,000 patient-years. A total of 24 ASCD patients received implantable cardioverter-defibrillators (ICDs). There was a nonsignificant trend of a lower rate of cardiac death in patients with ICDs than those without ICDs (p = 0.15).

CONCLUSIONS

The prognosis of patients with variant angina with ASCD was worse than other patients with variant angina. In addition, our findings supported ICDs in these high-risk patients as a secondary prevention because current multiple vasodilator therapy appeared to be less optimal.

Incidence and factors associated with mortality in 2,476 patients with variant angina in Korea

This study investigated the incidence and risk factors of mortality in 2,476 patients with variant angina (VA) using the National Health Insurance Service–National Sample Cohort between 2004 and 2011. The risk factors of all-cause and cardiac mortality were investigated using Cox proportional hazards model. Most patients (69.5%) were less than 65 years and 42.9% were women. During the median follow-up duration of 4.9 years, there were 178 (7.2%) and 95 (3.8%) cases of all-cause and cardiac mortality, respectively. Older age, hypertension, diabetes mellitus, poor medication adherence, low household income and tertiary teaching hospitals were independent predictors for all-cause mortality, while older age, hypertension, low household income and tertiary teaching hospitals were independent predictors for cardiac mortality. In conclusion, our findings suggest that traditional risk factor control and continued medication are important to improve VA outcomes, and that household income-level factors should be considered in the assessment of risk of VA patients.

Advancements in pharmacotherapy for angina

INTRODUCTION

Angina pectoris is the most prevalent symptomatic manifestation of ischemic heart disease, frequently leads to a poor quality of life, and is a major cause of medical resource consumption. Since the early descriptions of nitrite and nitrate in the 19th century, there has been considerable advancement in the pharmacologic management of angina. Areas covered: Management of chronic angina is often challenging for clinicians. Despite introduction of several pharmacological agents in last few decades, a significant proportion of patients continue to experience symptoms (i.e., refractory angina) with subsequent disability. For the purpose of this review, we searched PubMed and Cochrane databases from inception to August 2016 for the most clinically relevant publications that guide current practice in angina therapy and its development. In this article, we briefly review the pathophysiology of angina and mechanism-based classification of current therapy. This is followed by evidence-based insight into the traditional and novel pharmacotherapeutic agents, highlighting their clinical usefulness. Expert opinion: Considering the wide array of available therapies with different mechanism efficacy and limiting factors, a personalized approach is essential, particularly for patients with refractory angina. Ongoing research with novel pharmacologic modalities is likely to provide new options for management of angina.

Fluctuations in the amplitude of ST-segment elevation in vasospastic angina: Two case reports

RATIONALE

ST-segment elevation localizes an ischemic lesion to the coronary artery supplying the area of the myocardium reflected by the electrocardiographic leads. Dynamic ST-segment elevation can be due to severe transmural ischemia secondary to a thrombus, vasospasm, or a tightly fixed coronary artery lesion or a combination of these situations.

PATIENT CONCERNS

In this study, we report on two patients with angina who had fluctuations in ST-segment amplitude on serial electrocardiograms. The amplitude of ST-segment elevation varied between 1-20 mm.

DIAGNOSES

Vasospastic angina (VSA) was diagnosed based on electrocardiography and coronary angiography.

INTERVENTIONS

Calcium antagonists were prescribed for both patients.

OUTCOMES

No recurrent VSA was noted during outpatient follow-up.

LESSONS

VSA can be associated with fluctuations in the amplitude of ST-segment elevation, indicating dynamic coronary vasospasm in different locations and extensions in patients with VSA.

Impact of Diltiazem Alone versus Diltiazem with Nitrate on Five-Year Clinical Outcomes in Patients with Significant Coronary Artery Spasm

PURPOSE

Calcium channel blockers diltiazem and nitrate have been used as selective coronary vasodilators for patients with significant coronary artery spasm (CAS). However, no study has compared the efficacy of diltiazem alone versus diltiazem with nitrate for long-term clinical outcomes in patients with CAS.

MATERIALS AND METHODS

A total of 2741 consecutive patients without significant coronary artery disease with positive CAS by acetylcholine (Ach) provocation test between November 2004 and May 2014 were enrolled. Significant CAS was defined as a narrowing of >70% by incremental intracoronary injection of 20, 50, and 100 μg of Ach into the left coronary artery. Patients were assigned to either the diltiazem group (n=842) or the dual group (diltiazem with nitrate, n=1899) at physician discretion. To adjust for potential confounders, a propensity score matching (PSM) analysis was performed using the logistic regression model. After PSM analysis, two well-balanced groups (811 pairs, n=1622, C-statistic=0.708) were generated.

RESULTS

At 5 years, there were similar incidences in primary endpoints, including mortality, myocardial infarction, revascularization, and recurrent angina requiring repeat coronary angiography between the two groups. Diltiazem alone was not an independent predictor for major adverse cardiovascular events or recurrent angina requiring repeat coronary angiography.

CONCLUSION

Despite the expected improvement of endothelial function and the relief of CAS, the combination of diltiazem and nitrate treatment was not superior to diltiazem alone in reducing mortality and cardiovascular events up to 5 years in patients with significant CAS.

Vasodilator Therapy: Nitrates and Nicorandil

Nitrates have been used to treat symptoms of chronic stable angina for over 135 years. These drugs are known to activate nitric oxide (NO)-cyclic guanosine-3',-5'-monophasphate (cGMP) signaling pathways underlying vascular smooth muscle cell relaxation, albeit many questions relating to how nitrates work at the cellular level remain unanswered. Physiologically, the anti-angina effects of nitrates are mostly due to peripheral venous dilatation leading to reduction in preload and therefore left ventricular wall stress, and, to a lesser extent, epicardial coronary artery dilatation and lowering of systemic blood pressure. By counteracting ischemic mechanisms, short-acting nitrates offer rapid relief following an angina attack. Long-acting nitrates, used commonly for angina prophylaxis are recommended second-line, after beta-blockers and calcium channel antagonists. Nicorandil is a balanced vasodilator that acts as both NO donor and arterial K(+) ATP channel opener. Nicorandil might also exhibit cardioprotective properties via mitochondrial ischemic preconditioning. While nitrates and nicorandil are effective pharmacological agents for prevention of angina symptoms, when prescribing these drugs it is important to consider that unwanted and poorly tolerated hemodynamic side-effects such as headache and orthostatic hypotension can often occur owing to systemic vasodilatation. It is also necessary to ensure that a dosing regime is followed that avoids nitrate tolerance, which not only results in loss of drug efficacy, but might also cause endothelial dysfunction and increase long-term cardiovascular risk. Here we provide an update on the pharmacological management of chronic stable angina using nitrates and nicorandil.

Impact of Renin-Angiotensin System Inhibitors on Long-Term Clinical Outcomes of Patients With Coronary Artery Spasm

Background

Coronary artery spasm (CAS) is a well‐known endothelial dysfunction, and a major cause of vasospastic angina (VSA). The renin–angiotensin system (RAS) is known to be closely associated with endothelial function. However, there are only a few studies that investigated the impact of RAS inhibitor on long‐term clinical outcomes in VSA patients.

Methods and Results

A total of 3349 patients with no significant coronary artery disease, diagnosed with CAS by acetylcholine provocation test were enrolled for this study. Significant CAS was defined as having ≥70% narrowing of the artery after incremental injections of 20, 50, and 100 μg of acetylcholine into the left coronary artery. Patients were divided into 2 groups according to whether the prescription included RAS inhibitor or not (RAS inhibitor group: n=666, non‐RAS inhibitor group; n=2683). To adjust for any potential confounders that could cause bias, propensity score matching (PSM) analysis was performed using a logistic regression model. After PSM analysis, 2 matched groups (524 pairs, n=1048 patients, C‐statistic=0.845) were generated and their baseline characteristics were balanced. During the 5‐year clinical follow‐up, the RAS inhibitor group showed a lower incidence of recurrent angina (8.7% versus 14.1%, P=0.027), total death (0.0% versus 1.3%, P=0.045), and total major adverse cardiovascular events (1.0% versus 4.1%, P=0.026) than the non‐RAS inhibitor group.

Conclusions

Chronic RAS inhibitor therapy was associated with lower incidence of cardiovascular events in VSA patients in the 5‐year clinical follow‐up.

Pharmacotherapy of Vasospastic Angina

Vasospastic angina is a diagnosis of exclusion that manifests with signs and symptoms, which overlap with obstructive coronary artery disease, most often ST-segment elevation myocardial infarction. The pharmacotherapy that is available to treat vasospastic angina can help ameliorate angina symptoms. However, the etiology of vasospastic angina is ill-defined, making targeted pharmacotherapy difficult. Most patients receive pharmacotherapy that includes calcium channel blockers and/or long-acting nitrates. This article reviews the efficacy and safety of the pharmacotherapy used to treat vasospastic angina. High-dose calcium channel blockers possess the most evidence, with respect to decreasing angina incidence, frequency, and duration. However, not all patients respond to calcium channel blockers. Nitrates and/or alpha1-adrenergic receptor antagonists can be used in patients who respond poorly to calcium channel blockers. Albeit, evidence for use of nitrates and alpha1-adrenergic receptor antagonists in vasospastic angina is not as robust as calcium channel blockers and can exacerbate adverse effects when added to calcium channel blocker therapy. Despite having a clear benefit in patients with obstructive coronary artery disease, the benefit of beta-adrenergic receptor antagonists, statins, and aspirin remains unclear. More data are needed to elucidate whether or not these agents are beneficial or harmful to patients being treated for vasospastic angina. Overall, the use of pharmacotherapy for the treatment of vasospastic angina should be guided by patient-specific factors, such as tolerability, adverse effects, drug–drug, and drug–disease interactions.

Impact of Chronic Nitrate Therapy in Patients With Ischemic Heart Failure

PURPOSE

There is a lack of knowledge on the effects of nitrates alone in heart failure (HF). We aimed to assess the impact of nitrates use in the occurrence of ischemic events in patients with ischemic HF attending an HF clinic.

METHODS

We performed a retrospective analysis of a cohort of 632 patients managed in an HF clinic between January 2000 and December 2011. Patients with ischemic etiology were selected (n = 290). Patients were classified according to chronic nitrates use (n = 83 nitrates users vs n = 194) and followed up for 5 years for the occurrence of fatal or nonfatal myocardial infarction or stroke.

RESULTS

Nitrates users had more frequently diabetes, dyslipidemia, and higher body mass index but were less frequently treated with statins. Thirty adverse events were recorded (n = 16 in nitrates group). Variables significantly associated with the occurrence of the end point in univariate analysis were arterial hypertension, diabetes, and nitrates use. Male gender, beta-blockers, statin, and clopidogrel use had a protective effect on the occurrence of the end point. In multivariate analysis, nitrates use remained an independent predictor of adverse outcome when adjusted for each of the variables: arterial hypertension, gender, diabetes, beta-blocker, and clopidogrel use; however, when adjusted for statin use, nitrates were no longer associated with the outcome.

CONCLUSION

Long-term nitrates use in patients with ischemic HF was associated with higher occurrence of ischemic events, defined as fatal or nonfatal myocardial infarction or stroke. Our results, although from a retrospective analysis, do not support a role for chronic nitrate use in HF.

Organic Nitrate Therapy, Nitrate Tolerance, and Nitrate-Induced Endothelial Dysfunction: Emphasis on Redox Biology and Oxidative Stress

Organic nitrates, such as nitroglycerin (GTN), isosorbide-5-mononitrate and isosorbide dinitrate, and pentaerithrityl tetranitrate (PETN), when given acutely, have potent vasodilator effects improving symptoms in patients with acute and chronic congestive heart failure, stable coronary artery disease, acute coronary syndromes, or arterial hypertension. The mechanisms underlying vasodilation include the release of •NO or a related compound in response to intracellular bioactivation (for GTN, the mitochondrial aldehyde dehydrogenase [ALDH-2]) and activation of the enzyme, soluble guanylyl cyclase. Increasing cyclic guanosine-3',-5'-monophosphate (cGMP) levels lead to an activation of the cGMP-dependent kinase I, thereby causing the relaxation of the vascular smooth muscle by decreasing intracellular calcium concentrations. The hemodynamic and anti-ischemic effects of organic nitrates are rapidly lost upon long-term (low-dose) administration due to the rapid development of tolerance and endothelial dysfunction, which is in most cases linked to increased intracellular oxidative stress. Enzymatic sources of reactive oxygen species under nitrate therapy include mitochondria, NADPH oxidases, and an uncoupled •NO synthase. Acute high-dose challenges with organic nitrates cause a similar loss of potency (tachyphylaxis), but with distinct pathomechanism. The differences among organic nitrates are highlighted regarding their potency to induce oxidative stress and subsequent tolerance and endothelial dysfunction. We also address pleiotropic effects of organic nitrates, for example, their capacity to stimulate antioxidant pathways like those demonstrated for PETN, all of which may prevent adverse effects in response to long-term therapy. Based on these considerations, we will discuss and present some preclinical data on how the nitrate of the future should be designed.