Clinical implications of low-dose aspirin on vasospastic angina patients without significant coronary artery stenosis; a propensity score-matched analysis

Vasospastic angina: a review on diagnostic approach and management

Vasospastic angina (VSA) refers to chest pain experienced as a consequence of myocardial ischaemia caused by epicardial coronary spasm, a sudden narrowing of the vessels responsible for an inadequate supply of blood and oxygen. Coronary artery spasm is a heterogeneous phenomenon that can occur in patients with non-obstructive coronary arteries and obstructive coronary artery disease, with transient spasm causing chest pain and persistent spasm potentially leading to acute myocardial infarction (MI). VSA was originally described as Prinzmetal angina or variant angina, classically presenting at rest, unlike most cases of angina (though in some patients, vasospasm may be triggered by exertion, emotional, mental or physical stress), and associated with transient electrocardiographic changes (transient ST-segment elevation, depression and/or T-wave changes). Ischaemia with non-obstructive coronary arteries (INOCA) is not a benign condition, as patients are at elevated risk of cardiovascular events including acute coronary syndrome, hospitalization due to heart failure, stroke and repeat cardiovascular procedures. INOCA patients also experience impaired quality of life and associated increased healthcare costs. VSA, an endotype of INOCA, is associated with major adverse events, including sudden cardiac death, acute MI and syncope, necessitating the study of the most effective treatment options currently available. The present literature review aims to summarize current data relating to the diagnosis and management of VSA and provide details on the sequence that treatment should follow.

Vasospastic angina: Past, present, and future

Vasospastic angina (VSA) is characterized by episodes of rest angina that are responsive to short-acting nitrates and are attributable to coronary artery vasospasm. The condition is underdiagnosed as the provocation test is rarely performed. VSA, the most important component of non-obstructive coronary artery disease, can present with angina, be asymptomatic, or can even present with fatal arrhythmias and cardiac arrest. Although most patients with VSA respond well to vasodilating medications, prognosis does not improve as expected in most patients, suggesting the existence elusive prognostic factors and pathogenesis that warrant further exploration. Moreover, patients with either severe or refractory VSA barely respond to conventional treatment and may develop life-threatening arrhythmias or suffer sudden cardiac death during ischemic attacks, which are associated with immune-inflammatory responses and have been shown to achieve remission following glucocorticoid and immunoglobulin treatments. Our recent work revealed that inflammation plays a key role in the initiation and development of coronary spasms, and that inflammatory cytokines have predictive value for diagnosis. In contrast to the existing literature, this review both summarizes the theoretical and clinical aspects of VSA, and also discusses the relationship between inflammation, especially myocarditis and VSA, in order to provide novel insights into the etiology, diagnosis, and treatment of VSA.

Healed plaque erosion as a cause of recurrent vasospastic angina: a case report

Background

Recurrent vasospastic angina sometimes occurs. Fresh thrombi have been known to arise without plaque rupture at coronary spasm sites due to blood flow stagnation and intimal erosion caused by vasospasms. The relationship between recurrence of vasospastic angina and thrombus formation remains unclear.

Case summary

A 67-year-old man presented with sudden chest pain at rest. Electrocardiography and coronary angiography indicated vasospastic angina. His chest pain persisted despite the administration of benidipine, isosorbide mononitrate, nicorandil, and nifedipine. Coronary angiography performed one month after initial presentation showed stenosis refractory to isosorbide administration. Optical coherence tomography revealed a healed plaque, and a stent was deployed. The patient remained symptom-free at 1-year follow-up.

Discussion

Prolonged coronary vasospasm with limited coronary blood flow could induce total occlusion of the coronary artery, and acute thrombus formation, which resulted in healed plaque erosion. When vasospastic angina cannot be controlled, rapidly progressive stenosis caused by healed plaque erosion could be its underlying cause and mechanism. This report indicates that antiplatelet therapy may be a preventive option for future recurrent vasospastic angina, especially in those caused by healed plaques.

Current Evidence on Long-Term Prognostic Factors in Vasospastic Angina

Vasospastic angina (VSA) is characterized by a reversible spasm of the coronary arteries and is more prevalent in Asians. Vasodilators, such as calcium channel blockers, are effective in relieving coronary spasms and preventing clinical events. Therefore, the prognosis of VSA is generally known to be better than for significant organic stenosis caused by atherosclerosis. However, coronary vasospasm is sometimes associated with fatal complications such as sudden death, ventricular arrhythmia, and myocardial infarction. Thus, it is very important to identify and actively treat high-risk patients to prevent VSA complications. Here, we will review clinical factors associated with long-term prognosis in patients with VSA.

Intracoronary Thrombogenicity in Patients with Vasospastic Angina: An Observation Using Coronary Angioscopy

BACKGROUND

Despite significant interest in intracoronary thrombi in patients with vasospastic angina (VSA), the phenomenon remains unclarified. Therefore, we investigated a possible relationship using coronary angioscopy (CAS) in VSA patients.

METHODS

Sixty patients with VSA, for whom we could assess the spastic segment using CAS, were retrospectively studied. An intracoronary thrombus on CAS was a white thrombus and an erosion-like red thrombus. We verified the clinical characteristics and lesional characteristics as they determined the risk of intracoronary thrombus formation.

RESULTS

There were 18 (30%) patients with intracoronary thrombi. More of the patients with intracoronary thrombi were male, current smokers and had severe concomitant symptoms; however, no statistically significant difference was observed upon logistic regression analysis. There were 18 (26%) coronary arteries with intracoronary thrombi out of 70 coronary arteries recognised in the spastic segments. Furthermore, atherosclerotic changes and segmental spasms were significant factors responsible for such lesions.

CONCLUSION

Intracoronary thrombi occurred in 30% of VSA patients and much attention should be paid to the intracoronary thrombogenicity of VSA patients.

Impact of aspirin use on clinical outcomes in patients with vasospastic angina: a systematic review and meta-analysis

OBJECTIVES

The use of aspirin to prevent cardiovascular disease in vasospastic angina (VSA) patients without significant stenosis has yet to be investigated. This study aimed to investigate the efficacy of aspirin use among VSA patients.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

PubMed, Web of Science and Cochrane Central Register of Controlled Trials were searched for relevant information prior to October 2020.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Aspirin use versus no aspirin use (placebo or no treatment) among VSA patients without significant stenosis.

DATA EXTRACTION AND SYNTHESIS

Two investigators extracted the study data. ORs and 95% CIs were calculated and graphed as forest plots. The Newcastle-Ottawa Quality Assessment Scale tool and Begg's funnel plot were used to assess risk of bias.

RESULTS

Four propensity-matched cohorts, one retrospective analysis and one prospective multicentre cohort, in total comprising 3661 patients (aspirin use group, n=1695; no aspirin use group, n=1966) were included in this meta-analysis. Aspirin use and the incidence of major cardiovascular adverse events with follow-up of 1-5 years were not significantly correlated (combined OR=0.90, 95% CI: 0.55 to 1.68, p=0.829, I²=82.2%; subgroup analysis: OR=1.09, 95% CI: 0.81 to 1.47, I²=0%). No significant difference was found between aspirin use and the incidence of myocardial infarction (OR=0.62, 95% CI: 0.09 to 4.36, p=0.615, I²=73.8%) or cardiac death (OR=1.73, 95% CI: 0.61 to 4.94, p=0.444, I²=0%) during follow-up.

CONCLUSION

Aspirin use may not reduce the risk of future cardiovascular events in VSA patients without significant stenosis.

PROSPERO REGISTRATION NUMBER

CRD42020214891.

Guidelines for reasonable and appropriate care in the emergency department (GRACE): Recurrent, low-risk chest pain in the emergency department

This first Guideline for Reasonable and Appropriate Care in the Emergency Department (GRACE-1) from the Society for Academic Emergency Medicine is on the topic: Recurrent, Low-risk Chest Pain in the Emergency Department. The multidisciplinary guideline panel used The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach to assess the certainty of evidence and strength of recommendations regarding eight priority questions for adult patients with recurrent, low-risk chest pain and have derived the following evidence based recommendations: (1) for those >3 h chest pain duration we suggest a single, high-sensitivity troponin below a validated threshold to reasonably exclude acute coronary syndrome (ACS) within 30 days; (2) for those with a normal stress test within the previous 12 months, we do not recommend repeat routine stress testing as a means to decrease rates of major adverse cardiac events at 30 days; (3) insufficient evidence to recommend hospitalization (either standard inpatient admission or observation stay) versus discharge as a strategy to mitigate major adverse cardiac events within 30 days; (4) for those with non-obstructive (<50% stenosis) coronary artery disease (CAD) on prior angiography within 5 years, we suggest referral for expedited outpatient testing as warranted rather than admission for inpatient evaluation; (5) for those with no occlusive CAD (0% stenosis) on prior angiography within 5 years, we recommend referral for expedited outpatient testing as warranted rather than admission for inpatient evaluation; (6) for those with a prior coronary computed tomographic angiography within the past 2 years with no coronary stenosis, we suggest no further diagnostic testing other than a single, normal high-sensitivity troponin below a validated threshold to exclude ACS within that 2 year time frame; (7) we suggest the use of depression and anxiety screening tools as these might have an effect on healthcare use and return emergency department (ED) visits; and (8) we suggest referral for anxiety or depression management, as this might have an impact on healthcare use and return ED visits.

Smoking may be more harmful to vasospastic angina patients who take antiplatelet agents due to the interaction: Results of Korean prospective multi-center cohort

Background

The interaction between smoking and the use of antiplatelet agents on the prognosis of vasospastic angina (VA) is rarely investigated.

Methods

VA-Korea is a nation-wide multi-center registry with prospective design (n = 1812). The primary endpoint was the composite occurrence of acute coronary syndrome (ACS), symptomatic arrhythmia, and cardiac death. Log-rank test and Cox proportional hazard model were for statistical analysis. Also, we conducted interaction analysis in both additive and multiplicative scales between smoking and antiplatelet agents among VA patients. For additive scale interaction, relative excess risk due to interaction (RERI) was calculated and for multiplicative scale interaction, the ratio of hazard ratio (HR) was calculated. All statistical analysis conducted by Stata Ver 16.1.

Results

Patients who were smoking and using antiplatelet agents had the highest incidence rate in the primary composite outcome. The incidence rate was 3.49 per 1,000 person-month (95% CI: 2.30-5.30, log-rank test for primary outcome p = 0.017) and HR of smoking and using antiplatelet agents was 1.66 (95%CI: 0.98-2.81). The adjusted RERI of smoking and using antiplatelet agents was 1.10 (p = 0.009), and the adjusted ratio of HR of smoking and using antiplatelet agents was 3.32 (p = 0.019). The current study observed the interaction between smoking and using antiplatelet agents in both additive and multiplicative scales.

Conclusions

Smoking was associated with higher rates of unfavorable clinical outcomes among VA patients taking antiplatelet agents. This suggested that VA patients, especially those using antiplatelet agents should quit smoking.

Impairment of platelet NO signalling in coronary artery spasm: role of hydrogen sulphide

BACKGROUND AND PURPOSE

The pathophysiology of coronary artery spasm (CAS), with its associated ischaemic crises, is currently poorly understood and treatment is frequently ineffective. In view of increasing evidence that platelet-based defects may occur in CAS patients, we investigated platelet reactivity in CAS patients and whether symptomatic crises reflect activation of platelet-endothelial interactions.

EXPERIMENTAL APPROACH

CAS patients were evaluated during acute and/or chronic symptomatic phases and compared with healthy control subjects. Inhibition of ADP-induced platelet aggregation by the NO donor sodium nitroprusside (SNP) and plasma concentrations of syndecan 1 (glycocalyx shedding marker), tryptase (mast cell activation marker) and platelet microparticles were measured.

KEY RESULTS

Inhibition of platelet aggregation by SNP was diminished in chronic CAS, with further (non-significant) deterioration during symptomatic crises, whereas plasma concentrations of syndecan 1, tryptase and platelet microparticles increased. Treatment of patients with high-dose N-acetylcysteine (NAC) plus glyceryl trinitrate rapidly increased platelet responsiveness to SNP and decreased plasma syndecan 1 concentrations. The effect of NAC on platelet responsiveness to SNP was confirmed in vitro and mimicked by the H₂ S donor NaHS. Conversely, inhibition of enzymatic production of H₂ S attenuated NAC effect.

CONCLUSION AND IMPLICATIONS

CAS is associated with substantial impairment of platelet NO signalling. During acute symptomatic exacerbations, platelet resistance to NO is aggravated, together with mast cell activation and damage to both vasculature and platelets. NAC, via release of H₂ S, reverses platelet resistance to NO and terminates glycocalyx shedding during symptomatic crises: This suggests that H₂ S donors may correct the pathophysiological anomalies underlying CAS.

The impact of antiplatelet therapy on patients with vasospastic angina: A multicenter registry study of the Japanese Coronary Spasm Association

BACKGROUND

Antiplatelet therapy (APT) is generally used in patients with coronary artery disease. However, for patients with vasospastic angina (VSA), the impact of APT is not fully understood.

METHODS

In a multicenter registry study of the Japanese Coronary Spasm Association (n = 1429), patients with or without APT were compared. The primary endpoint was major adverse cardiac events (MACEs), defined as cardiac death, non-fatal myocardial infarction, unstable angina, heart failure and appropriate ICD (Implantable cardioverter defibrillator) shock. Propensity score matching and a multivariable cox proportional hazard model were used to adjust for selection bias for treatment and potential confounding factors.

RESULTS

In the whole population, 669 patients received APT, while 760 patients did not receive APT. Patients with APT had a greater prevalence of comorbidities, such as hypertension, diabetes, dyslipidemia and smoking, than those without APT. The prevalences of previous myocardial infarction, spontaneous ST changes, significant organic stenosis and medications including calcium channel blocker, nitrate, statin and angiotensin-converting enzyme inhibitor/angiotensin receptor blocker were greater in patients with APT than those without APT. After propensity matching (n = 335 for both groups), during the median follow-up period of 32 months, the incidence rate of MACE was comparable between the patients with and without APT (P = 0.24). MACEs occurred in 5.7% of patients with APT and in 3.6% of those without APT (P = 0.20). All-cause death occurred in 0.6% of patients with APT and 1.8% of those without APT (p = 0.16).

CONCLUSION

In this multicenter registry study, anti-platelet therapy exerted no beneficial effects for VSA patients.

Vasospastic angina: pathophysiology and clinical significance

The review discusses an analysis of the literature on various aspects of the pathogenesis, diagnosis and treatment of vasospastic angina (VA). Data on the prevalence of coronary artery spasm (CAS) in various populations, as well as risk factors and triggers, are presented. We considered pathophysiological mechanisms of CAS, including hyperreactivity of coronary smooth muscle cells, endothelial dysfunction, nonspecific inflammation, oxidative stress, magnesium deficiency, autonomic imbalance, etc. The relationship of CAS with coronary atherosclerosis and thrombosis is emphasized. Modern recommendations for the diagnosis and treatment of VA are presented. Invasive verification of CAS is performed by pharmacological provocation tests with certain contraindications. Calcium antagonists and their combination with long-acting nitrates play a key role in the treatment of VA. Medications with a prospect for use in VA are Rho-kinase inhibitors, ATP-sensitive potassium channel activators, alpha-1 blockers. The management of patients with refractory VA and the prospects for endovascular treatment are discussed. It was noted that patients with multi-vessel VA are more likely to develop life-threatening arrhythmias and sudden death.

Clopidogrel plus Aspirin Use is Associated with Worse Long-Term Outcomes, but Aspirin Use Alone is Safe in Patients with Vasospastic Angina: Results from the VA-Korea Registry, A Prospective Multi-Center Cohort

Anti-platelet agents are commonly used in vasospastic angina (VA) patients with comorbidity like coronary artery disease. However, long-term clinical outcomes in the use of aspirin, clopidogrel or the two agents together have rarely been investigated in VA patients. In a prospective study, we enrolled 2960 patients who received coronary angiography and ergonovine provocation test at 11 university hospitals in Korea. Among them, 1838 patients were diagnosed either with definite (n = 680) or intermediate (n = 1212) VA, using the criteria of chest pain, ECG changes and ergonovine provocation test results. They were analyzed according to their use of aspirin, clopidogrel or both, or no anti-platelet agent at all. The primary outcome was time to composite events of death from any cause, acute coronary syndrome (ACS) and symptomatic arrhythmia during a 3-year follow-up. A primary composite outcome was significantly more common in the aspirin plus clopidogrel group, at 10.8% (14/130), as compared with the non-antiplatelet group, at 4.4% (44/1011), (hazard ratio [HR] 2.41, 95% confidence interval [CI], 1.32–4.40, p = 0.004). With regard to the person-time event rate, similar results were shown, with the highest rate in the aspirin plus clopidogrel user at 4.72/1000 person months (95% CI, 2.79–7.96, log-rank test for primary outcome p = 0.016). The person-time event of the ACS rate was also highest in that group, at 2.81 (95% CI, 1.46–5.40, log-rank test for ACS p = 0.116). Kaplan-Meier survival analysis demonstrated poor prognosis in primary outcomes and ACS in aspirin plus clopidogrel users (log-rank test, p = 0.005 and p = 0.0392, respectively). Cox-proportional hazard regression analysis, adjusting for age, sex, history of coronary heart disease, hypertension, diabetes, presence or not of definite spasm, use of calcium channel blocker, demonstrated that the use of aspirin plus clopidogrel is an independent risk for the primary outcome (HR 2.01, CI: 1.07–3.81, p = 0.031). The aspirin-alone group had a similar primary and individual event rate compared to the no-antiplatelet agent group (HR 0.96, CI, 0.59–1.55, p = 0.872). Smokers using aspirin plus clopidogrel had poorer outcomes than non-smokers, with HR 6.36 (CI 2.31–17.54, p = 0.045 for interaction). In conclusion, among VA patients, aspirin plus clopidogrel use is associated with a poor clinical outcome at 3 years, especially in ACS. Aspirin alone appears to be safe for use in those patients.

Coronary spasm: It’s common, but it’s still unsolved

Coronary spasm is caused by a transient coronary narrowing due to the constriction of epicardial coronary artery, which leads to myocardial ischemia. More than 50 years have passed since the first recognition of coronary spasm, and many findings on coronary spasm have been reported. Coronary spasm has been considered as having pivotal roles in the cause of not only rest angina but also exertional angina, acute coronary syndrome, and heart failure. In addition, several new findings of the mechanism of coronary spasm have emerged recently. The diagnosis based mainly on coronary angiography and spasm provocation test and the mainstream treatment with a focus on a calcium-channel blocker have been established. At a glance, coronary spasm or vasospastic angina (VSA) has become a common disease. On the contrary, there are several uncertain or unsolved problems regarding coronary spasm, including the presence of medically refractory coronary spasm (intractable VSA), or an appropriate use of implantable cardioverter defibrillator in patients with cardiac arrest who have been confirmed as having coronary spasm. This editorial focused on coronary spasm, including recent topics and unsolved problems.

APPROACHES TO PERSONALIZED THERAPY

Approaches to personalized therapy based on practical work of physicians are discussed. Personalized treatment considers patient’s interests and position, mechanisms of symptoms, somatic and mental comorbidities, chrono medicine, environment, genetics, and prognosis. Personalized treatment may be more effective, safe and inexpensive in compare with of traditional standardized care based on randomized controlled trials and clinical practice guidelines. Limitations and weaknesses of medical guidelines of authoritative professional societies are also discussed. Recommendations of clinical guidelines are based on randomized controlled trials with strict selection of patients without severe comorbid diseases. Accordingly, trials and guidelines conclusions cannot be applied for patients with heavy comorbidity. This justifies the need for organizational solutions and computer programs for support personalized treatment of patients. It is important to develop institute of primary care physicians and to train specialists in field of comorbid somatic diseases and mental disorders.

Clinical efficacy of aspirin with identification of intimal morphology by optical coherence tomography in preventing event recurrence in patients with vasospasm-induced acute coronary syndrome

Using optical coherence tomography (OCT), we found that there were morphological differences in the coronary intima between patients with vasospasm-induced acute coronary syndrome (VACS) and those with stable variant angina. We investigated whether aspirin use would protect against chest pain recurrence in patients with VACS. A retrospective cohort study was performed. Patients with ST-segment elevation who were confirmed to have VACS by a provocation test were included. OCT was performed at the index event and when chest pain recurred to assess intimal morphology. Chest pain recurrence was defined as the first revisit to the emergency room with angina. Propensity score matching was performed between the aspirin and non-aspirin groups. For 48 months, 154 patients were followed (77 patients in each group). The baseline characteristics and OCT findings were well balanced between the two groups after propensity score matching. Myocardial infarction (17 vs. 3%, p = 0.003) and chest pain recurrence (26 vs. 9%, p = 0.006) occurred more frequently in the non-aspirin group than in the aspirin group. Multiple Cox regression analysis showed that aspirin use was a significant predictor of lower risk of myocardial infarction [hazard ratio (HR) 0.13; 95% confidence interval (CI) 0.03-0.61] and chest pain recurrence (HR 0.33; 95% CI 0.12-0.71) during the follow-up period, after adjustments for relevant covariates including OCT findings. The use of aspirin may have a preventive effect on myocardial infarction and chest pain recurrence in patients with VACS. Randomized controlled trials are necessary to confirm the result.