Letter by Yasue et al regarding article, "Clinical usefulness, angiographic characteristics, and safety evaluation of intracoronary acetylcholine provocation testing among 921 consecutive white patients with unobstructed coronary arteries".

Abstract

HomeCirculationVol. 131, No. 4Letter by Yasue et al Regarding Article, “Clinical Usefulness, Angiographic Characteristics, and Safety Evaluation of Intracoronary Acetylcholine Provocation Testing Among 921 Consecutive White Patients With Unobstructed Coronary Arteries” Free AccessLetterPDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessLetterPDF/EPUBLetter by Yasue et al Regarding Article, “Clinical Usefulness, Angiographic Characteristics, and Safety Evaluation of Intracoronary Acetylcholine Provocation Testing Among 921 Consecutive White Patients With Unobstructed Coronary Arteries” Hirofumi Yasue, MD, PhD, Yuji Mizuno, MD, PhD and Eisaku Harada, MD, PhD Hirofumi YasueHirofumi Yasue Division of Cardiovascular Medicine, Kumamoto Kinoh Hospital, Kumamoto Aging Research Institute, Kumamoto City, Japan Search for more papers by this author , Yuji MizunoYuji Mizuno Division of Cardiovascular Medicine, Kumamoto Kinoh Hospital, Kumamoto Aging Research Institute, Kumamoto City, Japan Search for more papers by this author and Eisaku HaradaEisaku Harada Division of Cardiovascular Medicine, Kumamoto Kinoh Hospital, Kumamoto Aging Research Institute, Kumamoto City, Japan Search for more papers by this author Originally published27 Jan 2015https://doi.org/10.1161/CIRCULATIONAHA.114.011332Circulation. 2015;131:e323To the Editor:Ong and coworkers1 reported that epicardial and microvascular spasm were frequent in white patients with unobstructed coronary arteries and that epicardial spasm was most often diffuse and located in the distal coronary segments. They combine epicardial and microvascular spasm together as coronary spasm and speculated that epicardial spasm is probably a sign of concomitant microvascular disease.1 Their findings are interesting and in agreement with those of previous studies regarding epicardial spasm or coronary spasm.2 However, we take issue with them when they combine epicardial and microvascular spasm together as coronary spasm for the following reasons:Patients with epicardial spasm or coronary spastic angina (CSA) may have preserved coronary microvascular function.3Responses to Ca-channel blockers, nitrates, and β-blockers as well as risk and precipitating factors1 differ, and treatment therefore may also differ between the epicardial and microvascular disorders.The abnormal ACh test in the absence of epicardial spasm may not necessarily mean microvascular spasm.In the accompanying editorial for this article, Kinlay defines “variant angina” as true coronary spasm with ST elevation on ECG occurring at rest and associated with focal occlusion of >90% in the proximal coronary segment and distinguishes it from angina with coronary vasoconstriction with ST depression or vasospastic angina.4 He assumes that true variant angina is a rare fish in the sea of coronary syndromes. However, the following points must be considered:The attack of coronary spasm may be associated with either ST elevation or depression depending on attacks in the same patients. ECG may shift between ST depression and elevation during the same attack. Severe diffuse vasoconstriction also is often associated with ST elevation and may shift into total or subtotal occlusion depending on doses of intracoronary ACh. Variant angina may be induced by exercise particularly in the early morning. Variant angina is therefore only 1 aspect of a continuous spectrum of myocardial ischemia caused by coronary spasm.CSA occurs most often from midnight to early morning and is usually not induced by exercise in the daytime. Moreover, there are daily, weekly, or monthly variations in the occurrence of CSA. Therefore, it is not an easy task to establish the diagnosis of variant angina or CSA even using Holter ECG monitoring. Indeed, Prinzmetal and colleagues were able to catch variant angina only by watching the patients nightly and recording ECG during the attack in the era before the Holter ECG monitoring became available. The difficulty of diagnosing CSA therefore does not necessarily mean the rarity of existence of CSA including variant angina. Moreover, CSA often coexists with obstructive coronary disease and can be induced by the intracoronary ACh even after myocardial revascularization.1,5 Predilection sites and risk factors differ, and treatment and prognosis therefore also differ between the 2 diseases.2 It is precisely for these reasons that provocation tests for CSA have been developed and widely used in East Asia including Japan and now also in Europe as reported by Ong and coworkers.1Hirofumi Yasue, MD, PhDYuji Mizuno, MD, PhDEisaku Harada, MD, PhDDivision of Cardiovascular MedicineKumamoto Kinoh HospitalKumamoto Aging Research InstituteKumamoto City, JapanSources of FundingThis work was supported in part by the Japan Heart Foundation, Tokyo, and the Japan Vascular Disease Research Foundation, Kyoto, Japan.DisclosuresNone.