Location of focal vasospasm provoked by ergonovine maleate within coronary arteries in patients with vasospastic angina pectoris

Innervation of the coronary arteries and its role in controlling microvascular resistance

The coronary circulation plays a crucial role in balancing myocardial perfusion and oxygen demand to prevent myocardial ischemia. Extravascular compressive forces, coronary perfusion pressure, and microvascular resistance are involved to regulate coronary blood flow throughout the cardiac cycle. Autoregulation of the coronary blood flow through dynamic adjustment of microvascular resistance is maintained by complex interactions among mechanical, endothelial, metabolic, neural, and hormonal mechanisms. This review focuses on the neural mechanism. Anatomy and physiology of the coronary arterial innervation have been extensively investigated using animal models. However, findings in the animal heart have limited applicability to the human heart as cardiac innervation is generally highly variable among species. So far, limited data are available on the human coronary artery innervation, rendering multiple questions unresolved. Recently, the clinical entity of ischemia with non-obstructive coronary arteries has been proposed, characterized by microvascular dysfunction involving abnormal vasoconstriction and impaired vasodilation. Thus, measurement of microvascular resistance has become a standard diagnostic for patients without significant stenosis in the epicardial coronary arteries. Neural mechanism is likely to play a pivotal role, supported by the efficacy of cardiac sympathetic denervation to control symptoms in patients with angina. Therefore, understanding the coronary artery innervation and control of microvascular resistance of the human heart is increasingly important for cardiologists for diagnosis and to select appropriate therapeutic options. Advancement in this field can lead to innovations in diagnostic and therapeutic approaches for coronary artery diseases.

Acute myocardial infarction following radiofrequency catheter ablation in a child: a case report on the mechanism of coronary artery occlusion assessed by cardiovascular imaging

Background

Radiofrequency ablation is a common treatment for atrioventricular nodal re-entrant tachycardia, even in paediatric patients weighing ≥15 kg, where outcomes are similar to those in adults. However, reports of acute coronary artery occlusion after radiofrequency ablation for atrioventricular nodal re-entrant tachycardia are rare.

Case summary

An 11-year-old girl with symptomatic atrioventricular nodal re-entrant tachycardia refractory to drug treatment underwent radiofrequency ablation. During the procedure, ST elevation was observed, and coronary angiography revealed occlusion of the right coronary artery at the segment 4 atrioventricular branch. Intravascular ultrasonography showed a narrowed lumen and an abnormal area of low echogenicity in the adjacent myocardium. After dilation with a 1.5 mm diameter balloon, blood flow was successfully restored. Follow-up coronary computed tomography angiography revealed residual stenosis in the right coronary artery at the segment 4 atrioventricular branch; however, blood flow to the distal occlusion was preserved. The patient was discharged without further complications.

Discussion

To the best of our knowledge, this is the first report of coronary artery occlusion following radiofrequency ablation for atrioventricular nodal re-entrant tachycardia, evaluated using intravascular ultrasonography and coronary computed tomography angiography. Based on the imaging findings, direct thermal injury was considered the cause of occlusion.

Effects of hallucinogenic drugs on the human heart

Hallucinogenic drugs are used because they have effects on the central nervous system. Their hallucinogenic effects probably occur via stimulation of serotonin receptors, namely, 5-HT2A-serotonin receptors in the brain. However, a close study reveals that they also act on the heart, possibly increasing the force of contraction and beating rate and may lead to arrhythmias. Here, we will review the inotropic and chronotropic actions of bufotenin, psilocin, psilocybin, lysergic acid diethylamide (LSD), ergotamine, ergometrine, N,N-dimethyltryptamine, and 5-methoxy-N,N-dimethyltryptamine in the human heart.

Coronary Spasm: Ethnic and Sex Differences

Coronary spasm (CS), which may occur at the epicardial (focal or diffuse spasm) and/or microvascular (microvascular spasm) level, is a well-established cause of myocardial ischaemia, in particular in patients with anginal chest pain despite unobstructed coronary arteries. The diagnosis of CS can be confirmed during coronary angiography by an additional provocation test with vasoactive substances such as acetylcholine. Due to partially inconsistent data from large clinical studies, especially between Asian and white CS patients, ethnic differences concerning the prevalence and angiographic patterns of CS seem to exist. Furthermore, several studies in patients with coronary vasomotor disorders pointed towards differences among male and female CS patients. This article gives an overview of ethnic- and sex-related differences in patients with CS.

Layered Plaque in Organic Lesions in Patients With Coronary Artery Spasm

Background

Coronary artery spasm plays a vital role in the pathogenesis of coronary plaques. We sought to investigate the plaque characteristics of co‐existing organic lesions in patients with coronary artery spasm in comparison to those without coronary artery spasm by intracoronary optical coherence tomography (OCT).

Methods and Results

We included 39 patients who presented with a symptom suspected of coronary spastic angina and had an organic lesion, defined as ≥plaque burden of 50% assessed by OCT. Coronary artery spasm was diagnosed by positive acetylcholine provocation test, or by spontaneous spasm detected during coronary angiography. A total of 51 vessels with an organic lesion were identified. Of these, coronary artery spasm was observed in 30 vessels (spasm), while not in 21 vessels (non‐spasm). Organic lesions in the spasm vessels, compared with those in the non‐spasm vessels, had a higher prevalence of layered plaque (93% versus 38%, P<0.001), macrophages (80% versus 43%, P=0.016), and intraplaque microchannels (73% versus 24%, P<0.001), and lower prevalence of macrocalcification (23% versus 62%, P=0.009) as assessed by OCT.

Conclusions

Layered plaque, macrophages, and intraplaque microchannels, were frequently observed in organic lesions in patients with coronary artery spasm. These findings suggest that coronary artery spasm induces local thrombus formation as well as active inflammatory response, therefore increasing the risk of rapid plaque progression and ischemic events in patients with coronary artery spasm.

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.

Role of acetylcholine spasm provocation test as a pathophysiological assessment in nonobstructive coronary artery disease

Coronary angiography (CAG) sometimes shows nonobstructive coronary arteries in patients with suspected angina or acute coronary syndrome (ACS). The high prevalence of nonobstructive coronary artery disease (CAD) in those patients has recently been reported not only in Japan but also in Western countries, and is clinically attracting attention. Coronary spasm is considered to be one of the leading causes of both suspected stable angina and ACS with nonobstructive coronary arteries. Coronary spasm could also be associated with left ventricular dysfunction leading to heart failure, which could be improved following the administration of calcium channel blockers. Because we rarely capture spontaneous attacks of coronary spasm with electrocardiograms or Holter recordings, an invasive diagnostic modality, acetylcholine (ACh) provocation test, can be useful in detecting coronary spasm during CAG. Furthermore, we can use the ACh-provocation test to identify high-risk patients with coronary spasm complicated with organic coronary stenosis, and then treat with intensive care. Nonobstructive CAD includes not only epicardial coronary spasm but also microvascular spasm or dysfunction that can be associated with recurrent anginal attacks and poor quality of life. ACh-provocation test could also be helpful for the assessment of microvascular spasm or dysfunction. We hope that cardiologists will increasingly perform ACh-provocation test to assess the pathophysiology of nonobstructive CAD.

Clinical outcome according to spasm type of single coronary artery provoked by intracoronary ergonovine tests in patients without significant organic stenosis

BACKGROUND

This study aimed to evaluate clinical implications of single vessel coronary spasm provoked by intracoronary ergonovine provocation test in Korean population.

METHOD

A total of 1248 patients who presented with single vessel coronary artery spasm induced by intracoronary ergonovine provocation test, excluding 1712 with negative spasms, multiple and mixed coronary artery spasms and missing data among 2960 patients in the VA-KOREA (Vasospastic Angina in Korea) registry, were classified into diffuse (n=705) and focal (n=543) groups.

RESULTS

The 24-month incidences of a composite primary endpoints (cardiac death, new-onset arrhythmia, and acute coronary syndrome) were determined. Over a median follow-up of 30months, the composite primary end point occurred more frequently in the focal type patients than in the diffuse type patients (primary endpoint: adjusted hazard ratio [aHR], 1.658; 95% confidence interval [CI] 1.272 to 2.162, P<0.001). Especially, unstable angina in ACS components played a major role in this effect (hazard ratio [HR], 2.365; 95% confidence interval [CI] 1.100 to 5.087, P=0.028).

CONCLUSION

Focal type of single vessel coronary artery spasm in vasospastic angina (VSA) patients is found to be associated with worse clinical outcomes. It is thought that the effect is stemmed from unstable angina among ACS rather than the other components of primary endpoint. Therefore, focal type of single vessel coronary artery spasm in patients with VSA should be more carefully assessed and managed with appropriate medication.

Coronary artery spasm: Current knowledge and residual uncertainties

Myocardial ischaemia results from a direct mismatch between oxygen supply and demand, commonly arising as a result of coronary atherosclerosis, microvascular dysfunction or acute thrombosis and luminal obstruction. However, transient ischaemia may also occur due to coronary spasm leading to acute and unexpected myocardial ischaemia without obvious visible coronary pathology. Aside from symptoms of chest pain, coronary spasm can cause infarction, LV impairment, promote life threatening arrhythmias and ultimately sudden cardiac death. While therapeutic options are available, controversies exist around diagnosis, pathology, management and prognosis. This review summarises some of the common questions in this area. In particular we explore and discuss the available evidence for the pharmacological treatment of coronary spasm, and strategies for identification and management of very high risk patients to try and reduce the incidence of sudden premature death.

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Myocardial ischaemia results from a mismatch between oxygen supply and demand.

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Spasm might lead to myocardial ischaemia without visible coronary pathology.

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Coronary spasm can cause infarction, LV impairment and sudden cardiac death.

Recurrent syncope attributed to left main coronary artery severe stenosis

Patients with acute coronary syndrome (ACS) rarely manifest as recurrent syncope due to malignant ventricular arrhythmia. We report a case of a 56-year-old Chinese male with complaints of paroxysmal chest burning sensation and distress for 2 weeks as well as loss of consciousness for 3 days. The electrocardiogram (ECG) revealed paroxysmal multimorphologic ventricular tachycardia during attack and normal heart rhythm during intervals. Coronary angiograph showed 90% stenosis in left main coronary artery and 80% stenosis in anterior descending artery. Two stents sized 4.0∗18 mm and 2.75∗18 mm were placed at left main coronary artery and anterior descending artery, respectively, during percutaneous coronary intervention (PCI). The patient was discharged and never had ventricular arrhythmia again during a 3-month follow-up since the PCI. This indicated that ventricular tachycardia was correlated with persistent severe myocardial ischemia. Coronary vasospasm was highly suspected to be the reason of the sudden attack and acute exacerbation. PCI is recommended in patients with both severe coronary artery stenosis and ventricular arrhythmia. Removing myocardial ischemia may stop or relieve ventricular arrhythmia and prevent cardiac arrest.

Coronary vasomotor response to intracoronary acetylcholine injection, clinical features, and long-term prognosis in 873 consecutive patients with coronary spasm: analysis of a single-center study over 20 years

BACKGROUND

The aim of this study was to elucidate the correlation between angiographic coronary vasomotor responses to intracoronary acetylcholine (ACh) injection, clinical features, and long-term prognosis in patients with vasospastic angina (VSA).

METHODS AND RESULTS

This is a retrospective, observational, single-center study of 1877 consecutive patients who underwent ACh-provocation test between January 1991 and December 2010. ACh-provoked coronary spasm was observed in 873 of 1637 patients included in the present analysis. ACh-positive patients were more likely to be older male smokers with dyslipidemia, to have a family history of ischemic heart disease, and to have a comorbidity of coronary epicardial stenosis than were ACh-negative patients. ACh-positive patients were divided into 2 groups: those with focal (total or subtotal obstruction, n=511) and those with diffuse (severe diffuse vasoconstriction, n=362) spasm patterns. Multivariable logistic regression analysis identified female sex and low comorbidity of coronary epicardial stenosis to correlate with the ACh-provoked diffuse spasm pattern in patients with VSA. Kaplan-Meier survival curve indicated better 5-year survival rates free from major adverse cardiovascular events in patients with diffuse spasm pattern compared with those with focal spasm pattern (P=0.019). Multivariable Cox hazard regression analysis identified diffuse spasm pattern as a negative predictor of major adverse cardiovascular events in patients with VSA.

CONCLUSIONS

ACh-induced diffuse coronary spasm was frequently observed in female VSA patients free of severe coronary epicardial stenosis and was associated with better prognosis than focal spasm. These results suggest the need to identify the ACh-provoked coronary spasm subtypes in patients with VSA.

Clinical implications of provocation tests for coronary artery spasm: safety, arrhythmic complications, and prognostic impact: multicentre registry study of the Japanese Coronary Spasm Association

AIMS

Provocation tests of coronary artery spasm are useful for the diagnosis of vasospastic angina (VSA). However, these tests are thought to have a potential risk of arrhythmic complications, including ventricular tachycardia (VT), ventricular fibrillation (VF), and brady-arrhythmias. We aimed to elucidate the safety and the clinical implications of the spasm provocation tests in the nationwide multicentre registry study by the Japanese Coronary Spasm Association.

METHODS AND RESULTS

A total of 1244 VSA patients (M/F, 938/306; median 66 years) who underwent the spasm provocation tests were enrolled from 47 institutes. The primary endpoint was defined as major adverse cardiac events (MACEs). The provocation tests were performed with either acetylcholine (ACh, 57%) or ergonovine (40%). During the provocation tests, VT/VF and brady-arrhythmias developed at a rate of 3.2 and 2.7%, respectively. Overall incidence of arrhythmic complications was 6.8%, a comparable incidence of those during spontaneous angina attack (7.0%). Multivariable logistic regression analysis demonstrated that diffuse right coronary artery spasm (P < 0.01) and the use of ACh (P < 0.05) had a significant correlation with provocation-related VT/VF. During the median follow-up of 32 months, 69 patients (5.5%) reached the primary endpoint. The multivariable Cox proportional hazard model revealed that mixed (focal plus diffuse) type multivessel spasm had an important association with MACEs (adjusted hazard ratio, 2.84; 95% confidence interval, 1.34-6.03; P < 0.01), whereas provocation-related arrhythmias did not.

CONCLUSION

The spasm provocation tests have an acceptable level of safety and the evaluation of spasm type may provide useful information for the risk prediction of VSA patients.

Disruption of coronary vasomotor function: the coronary spasm syndrome

Abnormal coronary vasoconstriction, or coronary spasm, can be the result of several factors, including local and neuroendocrine aberrations. It can manifest clinically as a coronary syndrome and plays an important role in the genesis of myocardial ischemia. Over the past half century, coronary angiography allowed the in vivo demonstration of spasm in patients who fit the initial clinical description of the condition as reported by Prinzmetal et al. Several clinical, basic, and more recently, genetic studies have provided insight into the pathogenesis, manifestations, and therapy of this condition. It is not uncommonly encountered in patients with coronary syndromes and absence of clearly pathologic lesions on angiography. Provocation tests utilizing pharmacologic and nonpharmacologic stimuli combined with imaging (echocardiography or coronary angiography) can help make the correct diagnosis. The use of calcium channel blockers and long-acting nitrates is currently considered standard of care and the overall prognosis appears to be good. The recent discovery of genetic abnormalities predisposing to abnormal spasm of the coronaries has stimulated interest in the development of targeted therapies for the management of this condition.

Multifocal severe coronary artery vasospasm mistaken for diffuse atherosclerosis: a case report

Spontaneous severe multivessel coronary artery vasospasm is a rare but important cause of morbidity. One-third of patients have normal coronary vasculature, and these pose a significant therapeutic dilemma as lack of clinical suspicion might potentially lead to unnecessary revascularization therapies. A patient with resting chest pain and ischaemic electrocardiography demonstrated severe coronary obstruction at catheter angiography. Preangioplasty further information highlighted spasm as the likely cause and the angiographic abnormalities resolved post intracoronary nitrate. This paper emphasises thorough history-taking and judicious use of nitrates during diagnostic coronary angiography in such patients. This may negate the need for more complex cardiac interventions.