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

Ischemia with non-obstructive coronary artery (INOCA): Non-invasive versus invasive techniques for diagnosis and the role of #FullPhysiology

Ischemia with non-obstructive coronary arteries (INOCA) is an increasingly recognized entity. It encompasses different pathophysiological subtypes (i.e., endotypes), including coronary microvascular dysfunction (CMD), vasospastic angina (VSA) and mixed entities resulting from the variable combination of both. Diagnosing INOCA and precisely characterizing the endotype allows for accurate medical treatment and has proven prognostic implications. A breadth of diagnostic technique is available, ranging from non-invasive approaches to invasive coronary angiography adjuvated by functional assessment and provocative tests. This review summarizes the strength and limitations of these methodologies and provides the rationale for the routine referral for invasive angiography and functional assessment in this subset of patients.

Insights into the invasive diagnostic challenges of coronary artery vasospasm - A systematic review

Coronary provocation testing is an essential diagnostic procedure when evaluating vasospastic angina. Invasive methods using acetylcholine or ergonovine are considered the current gold standard. Despite efforts from global cardiovascular institutions, current protocols vary in dosage, administration time, and procedural approach. In addition, concerns over the specificity of findings and potential complications have limited routine uptake of this procedure in clinical practice. This systematic review evaluates current diagnostic protocols, focusing on invasive provocation testing. We included studies using intracoronary provocation testing with acetylcholine or ergonovine for the assessment of coronary artery vasospasm that detailed specific elements of the procedure (dosage, administration time, etc.) and included ≥50 patients. A total of 28 articles met strict inclusion criteria. Our review highlights the heterogeneity between current diagnostic protocols for invasive provocation testing. We believe standardization of a diagnostic protocol will encourage both current and future cardiologists to incorporate such procedures in the evaluation of variant angina.

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.

Non-invasive diagnosis of vasospastic angina

Vasospastic angina (VSA), or variant angina, is an under-recognized cause of chest pain and myocardial infarction, especially in Western countries. VSA leads to a declined quality of life and is associated with increased morbidity and mortality. Currently, the diagnosis of VSA relies on invasive testing that requires the direct intracoronary administration of ergonovine or acetylcholine. However, invasive vasoreactivity testing is underutilized. Several non-invasive imaging alternatives have been proposed to screen for VSA. This review aims to discuss the strengths and limitations of available non-invasive imaging tests for vasospastic angina.

Does the intracoronary pressure differ according to two types (diffuse or focal) of coronary spasm?

BACKGROUND

Several reports show that two types of coronary vasospasm (diffuse and focal spasm) are associated with the severity or prognosis of coronary spasm in patients with vasospastic angina (VSA). It is unclear whether intracoronary pressure differs between the two spasm types.

AIM

To investigate such relationships using a pressure wire during the spasm provocation test (SPT) in patients with VSA.

METHODS

Eighty-seven patients with VSA (average age: 67 years; 50 men, 37 women) underwent SPT. During the SPT, a pressure wire was advanced into the distal portion of the right coronary artery and left anterior descending coronary artery, and the ratio of the intracoronary pressure to the aortic pressure (Pd/Pa) was continuously monitored. An SPT was performed using acetylcholine (ACh), and the presence of coronary spasm was defined as the presence of > 90% arterial narrowing in response to an ACh infusion, with the usual chest symptoms and/or ischemic ECG changes. Focal spasm was defined as total or subtotal spasm within one segment of the AHA classification, while diffuse spasm was defined as > 90% spasm with two or more segments.

RESULTS

Among 87 patients, the frequencies of metabolic syndrome and having coronary atherosclerosis were higher in the focal group (n = 33) than in the diffuse spasm group (n = 54, P < 0.05). In the vessel analyses, in these 134 spastic segments, diffuse and focal spasms were detected in 100 and 34 vessels, respectively. The Pd/Pa at baseline was similar in both groups (diffuse: 0.96 ± 0.05, focal: 0.95 ± 0.05, P = 0.35); however, the Pd/Pa during coronary spasm was lower in focal spastic vessels (0.66 ± 0.20) than in diffuse spastic vessels (0.76 ± 0.11, P < 0.01), and the reduction in Pd/Pa during an SPT was also lower in focal spastic vessels (-0.29 ± 0.20) than in diffuse spastic vessels (-0.18 ± 0.11, P < 0.01). The presence of focal spasm was a significant factor responsible for reduction in Pd/Pa during SPT.

CONCLUSION

These findings suggest that focal spasm may be more severe than diffuse spasm, judging from the intracoronary pressure during coronary spasm.

Coronary Vasospastic Angina: A Review of the Pathogenesis, Diagnosis, and Management

Vasospastic angina (VSA) is an under-appreciated cause of chest pain. It is characterised by transient vasoconstriction of the coronary arteries and plays a significant role in the pathogenesis of stable angina and acute coronary syndromes. Complex mechanistic pathways characterised by endothelial dysfunction and smooth muscle hypercontractility lead to a broad spectrum of clinical manifestations ranging from recurrent angina to fatal arrhythmias. Invasive provocation testing using intracoronary acetylcholine or ergonovine is considered the current gold standard for diagnosis, but there is a wide variation in protocols amongst different institutions. Conventional pharmacological therapy relies on calcium channel blockers and nitrates; however, refractory VSA has limited options. This review evaluates the pathophysiology, diagnostic challenges, and management strategies for VSA. We believe global efforts to standardise diagnostic and therapeutic guidelines will improve the outcomes for affected patients.

Nitrates vs. Other Types of Vasodilators and Clinical Outcomes in Patients with Vasospastic Angina: A Propensity Score-Matched Analysis

Although vasodilators are widely used in patients with vasospastic angina (VA), few studies have compared the long-term prognostic effects of different types of vasodilators. We investigated the long-term effects of vasodilators on clinical outcomes in VA patients according to the type of vasodilator used. Study data were obtained from a prospective multicenter registry that included patients who had symptoms suggestive of VA. Patients were classified into two groups according to use of nitrates (n = 239) or other vasodilators (n = 809) at discharge. The composite clinical events rate, including acute coronary syndrome (ACS), cardiac death, new-onset arrhythmia (including ventricular tachycardia and ventricular fibrillation), and atrioventricular block, was significantly higher in the nitrates group (5.3% vs. 2.2%, p = 0.026) during one year of follow-up. Specifically, the prevalence of ACS was significantly more frequent in the nitrates group (4.3% vs. 1.5%, p = 0.024). After propensity score matching, the adverse effects of nitrates remained. In addition, the use of nitrates at discharge was independently associated with a 2.69-fold increased risk of ACS in VA patients. In conclusion, using nitrates as a vasodilator at discharge can increase the adverse clinical outcomes in VA patients at one year of follow-up. Clinicians need to be aware of the prognostic value and consider prescribing other vasodilators.

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.

Prognostic implications of coronary artery stenosis and coronary spasm in patients with stable angina: 5-year follow-up of the Abnormal COronary VAsomotion in patients with stable angina and unobstructed coronary arteries (ACOVA) study

BACKGROUND

In the Abnormal COronary VAsomotion in patients with stable angina and unobstructed coronary arteries study, we showed that 62% of patients with stable angina and unobstructed coronary arteries had coronary spasm. In this study, we sought to assess the 5-year prognosis in these patients.

METHODS

Data regarding the following endpoints were obtained: death, non-fatal myocardial infarction, coronary event (=cardiac death or non-fatal myocardial infarction), persistent angina and repeated coronary angiography. Quality of life was assessed using the Seattle Angina Questionnaire.

RESULTS

Among patients with unobstructed coronary arteries there were three deaths (2.9%) and no non-fatal myocardial infarction. Among those with obstructive CAD 15 died (13.8%) and three had a non-fatal myocardial infarction (2.8%). Patients with obstructive CAD had a higher rate of all-cause death and coronary events compared to those without (P = 0.004). Persistent angina was more prevalent in patients with unobstructed coronaries (P = 0.042). Prognosis of patients with unobstructed coronaries regarding hard clinical events, persistent angina and repeated coronary angiography was independent of the presence of coronary spasm (all P > 0.05). However, spasm patients were more likely to take nitrate medication at follow-up (P = 0.029).

CONCLUSION

Patients with stable angina and unobstructed coronary arteries have a favorable prognosis regarding mortality and non-fatal myocardial infarction after 5 years compared to patients with obstructive CAD irrespective of the presence of coronary artery spasm. However, persistent angina remains a common issue in patients with unobstructed coronary arteries leading to a similar frequency of repeated invasive procedures as in patients with obstructive CAD.

Admission serum potassium levels and prognosis of vasospastic angina

Hypokalemia is a common electrolyte disturbance and is related to poor prognosis in patients with cardiovascular disease. However, the role of hypokalemia in patients with vasospastic angina (VSA) has not yet been studied. The present study enrolled 1454 patients diagnosed with VSA according to ergonovine provocation test results and available admission serum potassium data. The primary outcome was a composite of cardiac death, acute coronary syndrome, and new-onset life-threatening arrhythmia. Based on a hypokalemia definition as serum potassium concentration ≤ 3.5 mEq/L, the hypokalaemia group included 70 patients (4.8%). The median potassium levels were 3.4 mEq/L [interquartile range (IQR) 3.3-3.5] in the hypokalemia group and 4.1 mEq/L (IQR 3.9-4.3) in the no-hypokalemia group. The median follow-up duration was 764 days. Primary outcomes occurred in seven patients (10.0%) in the hypokalemia group and 51 patients (3.7%) in the no-hypokalemia group. The Kaplan-Meier analysis showed a higher cumulative incidence of primary outcomes in the hypokalemia group compared to that in the no-hypokalemia group (log-rank P = 0.014). Multivariate Cox regression analysis also showed that hypokalemia was an independent predictor of primary outcomes. In conclusion, hypokalemia at admission was associated with adverse clinical outcomes in VSA.

Clinical significance of prolonged chest pain in vasospastic angina

BACKGROUND

Patients with vasospastic angina (VSA) sometimes experience prolonged chest symptoms. The clinical characteristics of these patients have not been clarified.

AIM

To investigate the clinical characteristics of prolonged VSA patients.

METHODS

This study included 167 patients with VSA diagnosed by spasm provocation tests (SPTs) using acetylcholine, which recorded the frequencies of positive reactions to a low dose of acetylcholine (L-ACh), total occlusion due to spasm (TOC), focal spasm, and the unavoidable use of nitroglycerin (unavoidable-NTG) during SPTs. The patients underwent a medical interview that investigated the maximum duration and frequency of chest symptoms as well as the frequencies of variant angina and other serious symptoms. The patients were divided into two groups based on the maximal duration: The short-duration group (< 15 min; n = 114) and the long-duration group (≥ 15 min; n = 53). They were also divided into two groups based on the frequency of chest symptoms: The low-frequency group (< 4/mo; n = 88) and the high-frequency group (≥ 4/mo; n = 79).

RESULTS

The long-duration group showed higher frequencies of other serious symptoms (P < 0.001) and variant angina (P < 0.05) as well as higher frequencies of spasm induction by L-ACh (P < 0.05), TOC (P < 0.05), focal spasm (P < 0.01), and unavoidable-NTG (P < 0.01) than the short-duration group. These parameters did not differ significantly between the low-frequency and high-frequency groups.

CONCLUSION

These findings suggest that patients with VSA who experience prolonged chest symptoms may have more severe characteristics of VSA.

Hyperthyroidism Is Associated with the Development of Vasospastic Angina, but Not with Cardiovascular Outcomes

Vasospastic angina (VA) is a functional disease caused by the alteration of vasomotor tone. We investigated the association of hyperthyroidism with the development and prognosis of VA. Study data were obtained from a prospective multicenter registry that included patients who had symptoms suggestive of VA. Coronary angiography and an ergonovine provocation test were performed, and patients were classified into a VA and a non-VA group. Among 1239 patients with suspected VA, 831 patients were classified in the VA group. Hyperthyroidism was more common in the VA group than in the non-VA group (10.0% vs. 3.7%, p < 0.001). After adjusting for confounding factors, hyperthyroidism was independently associated with a 3.27-fold increased risk of VA. Especially in women, hyperthyroidism was associated with a 4.38-fold higher risk of VA. All-cause death rates did not differ according to the presence or absence of hyperthyroidism. Hyperthyroidism is independently associated with the occurrence of VA especially in women but did not affect the total death in VA patients. Clinicians need to be aware of the role of thyroid function in patients with suspected VA.

Clinical impact of statin therapy on vasospastic angina: data from a Korea nation-wide cohort study

The effect of statin therapy on reducing adverse cardiovascular events in vasospastic angina (VSA) has been inconsistent. Therefore, we investigated the association between statin therapy and adverse cardiovascular events in a large, prospective VSA cohort. The Variant Angina Korea registry consecutively enrolled 2960 patients suspected VSA. Among them, we included 1713 patients who were diagnosed with VSA based on coronary provocation test. We divided the patients into the statin (n = 744) and no-statin group (n = 914) according to the medication prescribed at discharge. The primary outcome was a composite of cardiac death, acute coronary syndrome, and new-onset life-threatening arrhythmia during a 3-year follow-up period. The primary outcome occurred in 32 patients (4.3%) in the statin and 28 patients (3.1%) in the no-statin group. In Kaplan-Meier analysis before and after propensity score matching, there was no significant difference in the cumulative incidence of primary outcomes between both groups. Multivariate Cox regression analysis demonstrated that the focal type of VSA was independent predictor of primary outcomes, but statin therapy was not. Furthermore, the lack of benefit of statin therapy for primary outcomes was consistently observed across the statin intensity and spasm characteristics. In conclusion, the present study demonstrated that statin therapy did not reduce adverse cardiovascular events in patients with VSA.

Differential prognosis of vasospastic angina according to presentation with sudden cardiac arrest or not: Analysis of the Korean Health Insurance Review and Assessment Service

BACKGROUND

The long-term prognosis of vasospastic angina (VSA) patients presenting with aborted sudden cardiac death (ASCD) is still unknown. We sought to compare the long-term clinical outcomes between VSA patients presenting with and without ASCD by retrospective analysis of a nationwide population-based database.

METHODS

A total of 6972 patients in the Health Insurance Review and Assessment database who were hospitalized in the intensive care unit with VSA between July 1, 2007 and May 31, 2015 were enrolled. Primary outcome was the composite of cardiac arrest and acute myocardial infarction after discharge.

RESULTS

Five hundred ninety-eight (8.6%) VSA patients presented with ASCD. On inverse probability of treatment weighting, ASCD patients had a significantly increased risk of the composite of cardiac arrest and acute myocardial infarction (adjusted hazard ratio, 2.52; 95% confidence interval, 1.72-3.67; p < 0.001) during the median follow-up duration of 4 years. The association of ASCD presentation with a worse outcome in terms of primary outcome was consistent across various subgroups, including comorbidity type and use of vasodilators (all p-values for interaction: non-significant). ASCD patients treated with an implantable cardioverter defibrillator (ICD) had a lower incidence of the composite of cardiac arrest and acute myocardial infarction during follow-up than those without an ICD (p = 0.009).

CONCLUSIONS

VSA patients that present with ASCD are at increased risk of cardiac arrest or myocardial infarction during long-term follow-up despite adequate vasodilator therapy. An ICD is a potential therapeutic option for secondary prevention.