Differential incidence and type of spasm according to coronary arterial location

Characterisation and distribution of human coronary artery innervation

BACKGROUND

A detailed understanding of the sympathetic innervation of coronary arteries is relevant to facilitate the development of novel treatment approaches.

AIMS

This study aimed to quantitatively examine periarterial innervation in human epicardial coronary arteries.

METHODS

Coronary arteries with adjacent epicardial adipose tissue were excised along the left main coronary artery (LMCA), left anterior descending artery (LAD), left circumflex artery (LCx), and right coronary artery (RCA) from 28 body donors and examined histologically. Immunofluorescence staining was performed to characterise sympathetic nerve fibres.

RESULTS

A total of 42,573 nerve fibres surrounding 100 coronary arteries (LMCA: n=21, LAD: n=27, LCx: n=26, RCA: n=26) were analysed. The nerve fibre diameter decreased along the vessel course (median [interquartile range]): (proximal 46 μm [31-73], middle 38 μm [26-58], distal 31 μm [22-46]; p<0.001), with the largest nerve fibre diameter along the LMCA (50 μm [31-81]), followed by the LAD (42 μm [27-72]; p<0.001). The total nerve fibre density was highest along the RCA (123 nerves/cm² [82-194]). Circumferentially, nerve density was higher in the myocardial tissue area of the coronary arteries (132 nerves/cm² [76-225]) than in the epicardial tissue area (101 nerves/cm² [61-173]; p<0.001). The median lumen-nerve distance was smallest around the LMCA (2.2 mm [1.2-4.1]), followed by the LAD (2.5 mm [1.1-4.5]; p=0.005).

CONCLUSIONS

Human coronary arteries are highly innervated with sympathetic nerve fibres, with significant variation in the distribution and density. Understanding these patterns informs pathophysiological understanding and, potentially, the development of catheter-based approaches for cardiac autonomic modulation.

Lack of Class I Vasoreactivity Testing for Diagnosing Patients With Coronary Artery Spasm

BACKGROUND

Vasoreactivity testing, such as intracoronary acetylcholine (ACh) or ergometrine (EM), is defined as Class I for the diagnosis of patients with vasospastic angina (VSA) according to recommendations from the Coronary Vasomotion Disorders International Study (COVADIS) group and guidelines from the Japanese Circulation Society (JCS).

HYPOTHESIS

Although vasoreactivity testing is a clinically useful tool, it carries some risks and limitations in diagnosing coronary artery spasm.

METHODS

Previous reports on vasoreactivity testing for diagnosing the presence of coronary spasm are summarized from the perspective of Class I.

RESULTS

There are several problems such as reproducibility, underestimation, overestimation, and inconclusive/nonspecific results associated with daily spasm. Because provoked spasm caused by intracoronary ACh is not always similar to that caused by intracoronary EM, possibly due to different mediators, supplementary use of these vasoreactivity tests is necessary for cardiologists to diagnose VSA when a provoked spasm is not revealed by each vasoactive agent.

CONCLUSIONS

Cardiologists should understand the imperfection of these vasoreactivity tests when diagnosing patients with VSA.

Multivessel Coronary Function Testing Increases Diagnostic Yield in Patients With Angina and Nonobstructive Coronary Arteries

BACKGROUND

Invasive CFT is the gold standard for diagnosing coronary vasomotor dysfunction in patients with ANOCA. Most institutions recommend only testing the left coronary circulation. Therefore, it is unknown whether testing multiple coronary territories would increase diagnostic yield.

OBJECTIVES

The aim of this study was to evaluate the diagnostic yield of multivessel, compared with single-vessel, invasive coronary function testing (CFT) in patients with angina and nonobstructive coronary arteries (ANOCA).

METHODS

Multivessel CFT was systematically performed in patients with suspected ANOCA. Vasoreactivity testing was performed using acetylcholine provocation in the left (20 to 200 μg) and right (20 to 80μg) coronary arteries. A pressure-temperature sensor guidewire was used for coronary physiology assessment in all three epicardial vessels.

RESULTS

This multicenter study included a total of 228 vessels from 80 patients (57.8 ± 11.8 years of age, 60% women). Compared with single-vessel CFT, multivessel testing resulted in more patients diagnosed with coronary vasomotor dysfunction (86.3% vs 68.8%; P = 0.0005), coronary artery spasm (60.0% vs 47.5%; P = 0.004), and CMD (62.5% vs 36.3%; P < 0.001). Coronary artery spasm (n = 48) predominated in the left coronary system (n = 38), though isolated right coronary spasm was noted in 20.8% (n = 10). Coronary microvascular dysfunction (CMD), defined by abnormal index of microcirculatory resistance and/or coronary flow reserve, was present 62.5% of the cohort (n = 50). Among the cohort with CMD, 27 patients (33.8%) had 1-vessel CMD, 15 patients (18.8%) had 2-vessel CMD, and 8 patients (10%) had 3-vessel CMD. CMD was observed at a similar rate in the territories supplied by all 3 major coronary vessels (left anterior descending coronary artery = 36.3%, left circumflex coronary artery = 33.8%, right coronary artery = 31.3%; P = 0.486).

CONCLUSIONS

Multivessel CFT resulted in an increased diagnostic yield in patients with ANOCA compared with single-vessel testing. The results of this study suggest that multivessel CFT has a role in the management of patients with ANOCA.

What is the meaning of provoked spasm phenotypes by vasoreactivity testing?

Coronary artery epicardial spasm is involved in the pathogenesis of many cardiac disorders. Vasoreactivity testing, such as intracoronary injection of acetylcholine (ACH) or ergonovine (ER), is the gold standard method for the diagnosis of vasospastic angina. Provoked epicardial spasm phenotypes are classified as focal spasm and diffuse spasm. Multiple factors, including sex, ethnicity, and use of coronary vasoactive stimulators, are related to the provoked phenotypes of epicardial spasm. Diffuse-provoked spasm is often observed in females, where focal-provoked spasm is markedly more common in males. ACH provokes more diffuse and distal spasms, whereas ER induces more focal and proximal spasms. Yellow plaque and coronary thrombi are often observed in lesions with focal spasms, and intimal thickness with a sonolucent zone is significantly more common in lesions with focal spasm. Furthermore, clinical outcomes in patients with focal spasm are unsatisfactory compared with those in patients with diffuse spasm. However, the reproducibility and eternality of provoked spasm phenotypes by vasoreactivity testing is uncertain. Coronary atherosclerosis or endothelial damage may affect coronary vasomotor tone. Although coronary artery spasm may persist in the same coronary artery, provoked coronary spasm phenotypes may exhibit a momentary coronary reaction by intracoronary ACH or ER testing.

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.

Which Coronary Artery Should Be Preferred for Starting the Coronary Spasm Provocation Test?

BACKGROUND

The spasm provocation test (SPT) is a critical test for diagnosing vasospastic angina (VSA). However, the choice of vessel to be preferred for initiating the SPT-the right coronary artery (RCA) or the left coronary artery (LCA)-is unclear. This study aimed to assess SPT results including SPT-related complications while initiating the SPT in the RCA and LCA.

METHODS

We enrolled 225 patients who underwent coronary angiography and SPTs. The SPT was first performed in the RCA in 133 patients (RCA group) and the LCA in 92 patients (LCA group). We defined VSA as >90% narrowing of the coronary artery during the SPT, accompanied by chest pain and/or ST-T changes on the electrocardiogram. When coronary spasm occurs in two or more major coronary arteries, it is referred to as a multivessel spasm (MVS). SPT-related complications comprised atrial fibrillation, ventricular fibrillation, and unstable hemodynamics following catecholamine use. Analyses using propensity score matching (PSM) were performed in 120 patients.

RESULTS

No significant differences in the frequencies of VSA and complications were observed between the two groups (RCA: 79% and 19%, respectively; LCA: 85% and 22%, respectively). In both groups, spasms were most frequently provoked in the left anterior descending coronary artery (both p < 0.001) whereas spasms in the left circumflex coronary artery (LCX) were higher in the LCA group than in the RCA group (p = 0.015). Furthermore, no significant difference in the frequency of MVS was observed between both groups (RCA: 50%, LCA: 62%; p = 0.122). After PSM, no significant difference in the frequencies of VSA and complications were observed between the two groups (RCA: 82% and 15%, respectively; LCA: 88% and 18%, respectively). The frequencies of LCX spasms (RCA: 8%, LCA: 23%; p = 0.022) and MVS (RCA: 40%, LCA: 62%; p = 0.020) were higher in the LCA group than in the RCA group.

CONCLUSIONS

Although the diagnostic rate of VSA and frequency of SPT-related complications were similar in the two groups, the frequency of MVS was higher in the LCA group than in the RCA group because of the increase in the number of LCX spasms. A routine SPT may be started from the LCA.

Vasospastic angina in women: Clinical backgrounds and prognoses of patients younger than and older than 60 years

BACKGROUND

We frequently encounter cases of women with vasospastic angina (VSA). Additionally, some women with VSA are younger than 60 years old. However, it is unknown whether the characteristics of VSA in women aged < 60 years are different from those in women aged ≥ 60 years.

AIM

To investigate and compare the clinical characteristics and prognosis of VSA in women aged < 60 years from those in women aged ≥ 60 years.

METHODS

We enrolled 94 women with VSA who were diagnosed using the spasm provocation test. According to the age at diagnosis, the patients were divided into two groups: Group Y (age < 60 years, n = 17) and Group O (age ≥ 60 years, n = 77). Flow-mediated dilation (FMD) and nitroglycerin (NTG)-induced dilation (NID) of the brachial artery were performed and assessed using brachial ultrasonography. Moreover, conventional coronary risk factors, such as atherosclerotic lesions (stenosis > 20%) detected using coronary angiography and focal spasms (coronary spasm within one segment of one coronary artery), and major cardiovascular adverse events (MACE) were assessed in both groups.

RESULTS

Smoking was more prevalent in Group Y than in Group O (P = 0.04). FMD was similar in both groups (Group O: 4.3% ± 3.2%, Group Y: 4.5% ± 3.3%; P = 0.75), whereas NID was higher in Group Y (20.5% ± 8.6%) than in Group O (13.6% ± 5.3%, P < 0.01). Atherosclerosis was not detected in Group Y but was detected in Group O (61%, P < 0.01). Focal spasms were less frequent in Group Y (12%) than in Group O (38%, P = 0.04). The incidence of major adverse cardiac events did not differ between the two groups (P = 0.40).

CONCLUSION

Women aged < 60 years with VSA have less atherosclerotic lesions and focal spasms. These characteristics may be affected by smoking habits and vascular smooth muscle dysfunction.

Clinical characteristics in patients with rest angina and hypoplastic right coronary artery

Hypoplastic coronary artery disease is a rare congenital abnormality reported to be associated with myocardial infarction and sudden cardiac death. Provoked positive spasm in the left circumflex coronary artery (LCX) with pharmacological spasm provocation tests was remarkably lower than other coronary arteries. We sometimes encountered patients with rest angina and hypoplastic right coronary artery (H-RCA). Among 5953 patients with diagnostic and follow-up coronary arteriography, we found 93 patients (1.6%) with H-RCA. During the same period, we could perform spasm provocation tests in 564 patients with rest angina including 13 patients with H-RCA and 249 patients with effort angina including 10 patients with H-RCA. Pharmacological spasm provocation tests were performed in 51 of 93 patients including 34 patients with ischemic heart disease (IHD) and 17 patients with non-IHD. Provoked spasm incidence in patients with IHD was higher than in those with non-IHD but not significant (52.9% vs. 29.4%, p = 0.1114). Provoked positive spasm in the LCX in patients with rest angina and H-RCA was significantly higher than that in those without H-RCA (69.2% vs. 23.4%, p < 0.001). Provoked spasm on both left anterior descending artery and LCX in patients with rest angina and H-RCA was also remarkably higher than in those without H-RCA (53.8% vs. 3.1%, p < 0,001). There were no clinical differences between patients with and without H-RCA rest angina. Two-vessel spasm (61.5% vs. 0%, p < 0.01) and LCX-provoked spasm (69.2% vs. o%, p < 0.01) were significantly higher in patients with H-RCA and rest angina than that in those with H-RCA and effort angina. In patients with rest angina and H-RCA, LCX-positive spasm was significantly higher and these patients may have a potential of high disease activity in the clinic as a coronary spastic angina.

Dose maximal acetylcholine dose into the left coronary artery affect the positive provoked spasm in the left circumflex artery?

BACKGROUND

Positive provoked spasm in the left circumflex artery (LCX) is lower than that in the left anterior descending artery and right coronary artery (RCA).

PATIENTS AND METHODS

We examined the provoked positive spasm in the LCX between the maximal acetylcholine (ACh) 100 μg period (January 1991 to July 2012, 1474 patients: the former period) and the maximal ACh 200 μg period (August 2012 to August 2018, 336 patients: the latter period). ACh was injected in incremental dose of 20/50/100/200 μg into the left coronary artery and of 20/50/80 μg into the RCA. Positive spasm was defined as at least 90% stenosis and usual chest symptoms or ischemic ECG changes.

RESULTS

Provoked positive spasm in the latter period was significantly higher than that in the former period (65.5 vs. 39.1%, P < 0.001). The positive spasm increase of RCA and left anterior descending artery was 143 and 159%, whereas the increase of LCX was 204%. Multiple-vessel spasm was also increased in the latter period.

CONCLUSION

Maximal ACh dose into the left coronary artery may affect the positive spasm in the LCX and multiplevessel spasm.

Relationships between more than 90% coronary luminal narrowing induced by ergonovine provocation test and ECG ischemic change as well as chest symptoms

In the clinic, patients with ≥90% luminal narrowing during ergonovine (ER) testing had variable response. We investigated ischemic findings and chest symptoms in patients with ≥90% luminal narrowing when performing ER tests, retrospectively. We performed 1210 ER tests over 26 years (1991-2016). We analyzed chest symptoms and positive ischemic ECG changes during ER tests. More than 90% luminal narrowing was found in 352 patients (29.1%) including 211 patients in the right coronary artery (RCA) and 217 patients in the left coronary artery (LCA). Chest symptom was observed in 290 patients (82.4%) including 162 patients in the RCA and 179 patients in the LCA. ST elevation was found in 154 patients including 98 in the RCA and 73 patients in the LCA, while ST depression was recognized in 81 patients including 38 patients in the RCA and 62 patients in the LCA. Two-third of patients with ≥90% luminal narrowing had significant ischemic ECG changes, whereas 60.5% of patients with ≥90% luminal narrowing complained usual chest pain accompanied with significant ischemic ECG changes. Unusual chest symptom was complained in 7.1% of patients with ≥90% luminal narrowing. Neither chest symptom nor ECG changes was found in 48 patients (13.6%) with ≥90% luminal narrowing. We should understand some limitation to diagnose positive coronary spasm during ER tests.

Differential Incidence and Morphology of Spasm According to Coronary Arterial Location by Intracoronary Ergonovine Spasm Provocation Testing

BACKGROUND

We reported less provoked spasm in the left circumflex artery (LCX) by acetylcholine testing compared with the left anterior descending artery (LAD) and right coronary artery (RCA), so we investigated the clinical characteristics of provoked spasm in the LCX by ergonovine (ER) testing.Methods and Results:We retrospectively analyzed 1,185 consecutive cases of intracoronary ER testing during 25 years. Maximal ER dose was 64 μg into the left coronary artery (LCA) and 40 μg into the RCA. Positive spasm was defined as a transient ≥90% narrowing and usual chest symptoms or ischemic ECG changes. Positive provoked spasm was recognized in 347 patients (29.3%), including 207 RCA spasms, 166 LAD spasms, and 79 LCX spasms. Spasm was provoked in the LCX significantly less than in the other vessels (P<0.001). LCX-provoked spasm was obtained in 79 patients consisting of 16 patients (20.3%) with triple-vessel spasm, 38 patients (48.1%) with double-vessel spasm and 25 patients (31.6%) with single-vessel spasm. Less than 70% patients with LCX-provoked spasm had multiple spasms, whereas approximately 60% patients had single-vessel spasm in the RCA (64.3%) or LAD (59.6%). In 25 patients with LCX single-vessel spasm, 18 patients (72.0%) had a focal spasm.

CONCLUSIONS

Under maximal ER dose of 64 μg into the LCA, LCX-provoked spasm occurred significantly less than spasm in the other vessels and less than 70% patients had multiple spasms.