Spontaneous Multivessel Coronary Artery Dissection

pg. E5 - E6 ABSTRACT: As opposed to iatrogenic coronary dissection, spontaneous dissection is an extremely rare clinical condition. Typically seen in a single coronary vessel of peripartum women presenting with acute coronary syndrome, there are isolated case reports of men presenting multivessel involvement for this life-threatening condition. We describe a 54-year-old male with a history of diabetes, hypertension and methamphetamine abuse who presented to the emergency after a brief, witnessed cardiac arrest. Admission ECG revealed sinus tachycardia with inferior Q waves. He was found to have frequent runs of non-sustained ventricular tachycardia and minimal troponin-T elevation. His 2-D echocardiogram showed apical akinesis with an ejection fraction of 50%. Cardiac catheterization revealed a patent left main artery with a spontaneous dissection involving the mid to distal LAD artery, as well as large first diagonal branch with proximal dissection. His dominant RCA also showed long spontaneous dissection extending from proximal to distal vessel, along with distal focal 90% atherosclerotic lesion. Ramus intermedius and left circumflex vessels were free of disease. The patient underwent a 2-vessel coronary artery bypass grafting (CABG) with excellent outcome. Although cocaine abuse has been known to be associated with spontaneous dissection, this is the first reported case of a methamphetamine user presenting with multivessel coronary dissection. J INVASIVE CARDIOL 2009;21:E5–E6 Key words: apical akinesis, methamphetamine abuse Spontaneous coronary artery dissection (SCAD) is a rare and unusual cause of myocardial ischemia and sudden death.1 First described by Pretty in 1931, it was primarily a diagnosis made on autopsy before the use of coronary angiograms.2 It has been found to be associated with various pathophysiological states such as pregnancy, post-partum period, collagen diseases, cocaine abuse, oral contraceptive use, and severe hypertension. With fewer than 200 cases reported in literature, the majority (80%) occur in young women in their peri-partum period and usually involve a single coronary vessel.3,4 Outside of this group, there are only anecdotal case reports of spontaneous multivessel coronary involvement for this potentially life-threatening condition.5,6 Although methamphetamine use has been implicated in carotid and aortic dissection, this is the first reported case of coronary dissection suspected to be a result of methamphetamine abuse. Case report. Our patient is a 54-year -old male with a history of hypertension, diabetes and polysubstance abuse, including tobacco, alcohol and methamphetamines who was admitted to the emergency after a witnessed cardiac arrest. Apparently, the patient was playing a video game a few minutes after having used methamphetamines when he passed out. There was no preceding history of chest pain, shortness of breath or palpitations prior to the event. His sister called emergency medical services, who arrived to find the patient awake and trying to sit up. His vital signs included a BP of 146/82, sinus tachycardia at 108/minute with frequent premature ventricular complexes (PVC). He was afebrile and saturating well on minimal oxygen per nasal cannula and was transferred to the emergency department. Hospital course. The patient’s emergency room physical examination showed a slightly confused but awake and alert male who appeared to be in minimal distress. There was no evidence of any focal neurological deficit. His head and neck examination failed to reveal any significant bruit or jugular venous distension. His chest was clear to auscultation and sinus tachycardia with multiple PVCs was noted. However, there were no other abnormal heart sounds or murmurs heard. Abdominal and lower extremity exam was unremarkable. The patient denied any previous episodes of syncope or history suggestive of angina or heart failure. He did admit to daily methamphetamine and tobacco use but denied using cocaine in the last 20 years. Admission ECG revealed non-specific ST changes with Q waves in the inferior leads. Telemetry evaluation showed multiple runs of non-sustained ventricular tachycardia. His laboratory examination was unremarkable except for mildly elevated troponin-I of 0.1 ng/ml. A urine drug screen was positive for methamphetamines. Initial chest X-ray and non-contrast CT scan of the head was also within normal limits. At this time it was believed that his syncope was likely arrhythmogenic in etiology and a cardiac work-up was initiated. A bedside 2 D echocardiogram revealed an ejection fraction of 50% with apical akinesis but no evidence of valvular or structural heart disease. A decision was made to proceed with cardiac catheterization to rule out coronary artery disease as the underlying cause of focal cardiomyopathy and arrhythmia. It revealed a patent left main artery which trifurcated into LAD, non-dominant left circumflex and ramus intermedius branches. His LAD was described as a large caliber vessel with spontaneous dissection involving the mid-distal segment (Figure 1). It gave rise to a large diagonal branch, which also showed evidence of dissection in its proximal segment. The ramus and circumflex branches were free of significant disease. Injection of the dominant RCA showed another large, spontaneous dissection extending from the proximal to distal segment (Figure 2). The ostial portion was disease free, however there was a focal lesion involving 90% of lumen in the distal RCA. The ejection fraction was confirmed at 50% with an unremarkable aortogram. At this point consultation with cardio-thoracic surgery was obtained and given his diffuse, multivessel involvement it was agreed that the patient would benefit from coronary artery bypass graft surgery (CABG). After undergoing a successful two-vessel bypass to the distal LAD and RCA, the patient was discharged home and continues to do well after 8 months of follow up. Discussion. SCAD is a rare cause of acute coronary syndrome (ACS). With only 152 cases reported by Kamineni et al on a literature review from 1952–2002, the reported incidence varies from 0.1–1.1% of all ACS presentations.4 Patients with SCAD are usually divided into 3 groups — those (a) with significant atherosclerosis; (b) in their peri-partum period or associated with oral contraceptive use or (c) idiopathic.1,3–5 Women are considered to be at a higher risk and typically lack the traditional risk factors for coronary atherosclerosis. The usual time for presentation is during pregnancy or up to 10 weeks post-partum and the LAD or left main artery are the most common culprit vessels. In contrast, men usually present later in life, have associated atherosclerotic risk factors and the RCA is most commonly involved. The precise etiology and pathogenesis of SCAD is believed to be multifactorial and mostly unknown. Thayer et al proposed disruption of the vasa vasorum with intramedial hemorrhage with subsequent dissection.8 Rabinowitz et al postulated medial weakness secondary to accumulation of eosinophils and secretion of lytic enzymes, while a defect of collagen metabolism or cystic medial degeneration have also been proposed.9 In the past, diagnosis was mostly based on autopsy findings; however angiography is the current gold standard modality. Given the rarity of this condition and the wide variety of clinical presentation scenarios, the optimal therapy is less well defined. The decision to pursue medical management, percutaneous intervention or surgical revascularization is based on the clinical presentation, extent of dissection and the amount of myocardium at risk. Conservative treatment with antiplatelet agents, beta blockers etc. may be reasonable in asymptomatic, stable patients with limited vessel involvement. Percutaneous stenting is reasonable in symptomatic patients with single vessel (not including left main) involvement. Surgical revascularization is preferred in patients with multiple vessel involvement including left main, significant luminal compromise and recurrent ischemia. Our patient did have evidence of mild diffuse atherosclerotic coronary disease in the presence of traditional risk factors such as diabetes and hypertension. His work-up did not reveal any evidence of collagen vascular disease or recent cocaine use. This led us to consider the link between coronary dissection and methamphetamine use. Methamphetamines may induce vasospasm or result in hypertension, vasculitis, or direct vascular toxicity. Its abuse has been associated with aortic dissection as well as carotid artery dissection in published case reports.10, 11 According to our knowledge, this is the first reported case of multivessel SCAD potentially related to methamphetamine use. Conclusion. The diagnosis of SCAD should be considered in any patient who presents with symptoms suggestive of acute myocardial ischemia, particularly in young subjects without traditional risk factors for coronary artery disease. Urgent coronary angiography is indicated to establish the diagnosis and to determine the appropriate therapeutic approach. Although a clear correlation between methamphetamine use and coronary dissection is not known, we suggest that it be considered in as a potential risk factor of SCAD From the Division of Cardiology, Department of Medicine, St John Hospital and Medical Center, Detroit, Michigan. The authors report no conflicts of interest regarding the content herein. Manuscript submitted June 18, 2009, provisional acceptance given July 13, 2009, final version accepted July 24, 2009. Address for correspondence: Manreet Kanwar, MD, St John Hospital and Medical Center, 22101 Moross Road, 2nd Floor VEP, Cardiac Cath Lab, Detroit, MI 48236. E-mail: manreet.kanwar@stjohn.org

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