Survival after Spontaneous Coronary Artery Dissection Presenting with Ventricular Fibrillation Arrest

Spontaneous coronary artery dissection (SCAD) is an infrequently documented etiology of myocardial ischemia, infarction and sudden cardiac death (SCD). There have been approximately 160 reported cases since the first description in 1931. In > 70% of these cases, the diagnosis was based on postmortem examination. The exact mechanism of SCAD remains unknown. Typical coronary risk factors are usually not present. An association, however, has been documented with female gender,^1,“3 pregnancy,^4,5 vasospasm,¹ blunt trauma,⁶ vigorous exercise^7,8 and cocaine.⁹ Premortem diagnosis rests on documentation of dissection. The angiographer must have a high index of suspicion in order to confirm the diagnosis, given the spectrum of possible angiographic findings. Treatment modalities have included medical management,¹⁰ surgical revascularization,¹¹ surgical intramural hematoma resection,¹² thrombolytics,^13,14 immunosuppressive therapy¹⁵ and percutaneous coronary intervention.^16,17 We present the second reported case of survival from SCAD complicated by SCD. Our patient is a 37-year-old, otherwise healthy, female with a medical history negative for traditional cardiac risk factors. She presented to the emergency department with active chest pain. She was in her usual state of good health until the morning of presentation when she noted acute onset of severe substernal chest pain with associated diaphoresis while standing in formation. After approximately 30 minutes of persistent symptoms, she presented to the emergency room for evaluation. Medical and surgical history were unremarkable and included no connective tissue disease. She was not taking any medications and specifically denied the use of dietary supplements/stimulants, cocaine or amphetamines. Her family history was negative for atherosclerotic coronary artery disease. The presenting electrocardiogram demonstrated hyperacute T-waves in leads V2-4 (Figure 1). During her initial evaluation in the emergency department, she sustained a ventricular fibrillation arrest. The patient was subsequently defibrillated with 200 joules with a return to normal sinus rhythm and resolution of her chest pain and electrocardiographic changes (Figure 2). A bedside transthoracic echocardiogram (TTE) revealed a hypokinetic left ventricular apex and a moderately depressed ejection fraction. Emergent coronary angiography was then performed, demonstrating a mid-LAD dissection (Figure 3) with TIMI 2 flow (Figure 4). Left ventriculogram confirmed apical hypokinesis. She was medically managed with 72 hours of unfractionated heparin, aspirin, beta blockade, ACE inhibition, and HMG-CoA reductase inhibition. Serial cardiac enzymes revealed a mild troponin elevation to 2.3 (normal is < 0.08), in the context of normal creatine phosphokinase that peaked in less than 24 hours and is consistent with an aborted myocardial infarction associated with minimal myocardial necrosis. Additional significant lab data included a serum and urine drug screen that was negative for amphetamines or cocaine, as well as a negative HCG test. The patient's hospital course was uneventful, with no evidence of mechanical failure or recurrent arrhythmia. On hospital day-six, repeat coronary angiography was performed, demonstrating restoration of TIMI 3 flow with persistence of a small amount of extra luminal dye with delayed filling and washout characteristics at the mid-LAD coronary artery, consistent with a healing dissection. Repeat TTE was significant for normalization of regional wall motion abnormality. Prior to discharge, the patient underwent a full Bruce protocol exercise stress test which was clinically and electrically negative and notable for good exercise capacity. At six-month follow-up, a full Bruce protocol exercise stress test with myocardial perfusion imaging was performed. The study was again clinically and electrically negative, with imaging demonstrating a normal ejection fraction, normal wall motion and no evidence of ischemia or infarction. During 18 months of follow-up care, she has remained asymptomatic and without any manifestation of connective tissue disease. SCAD is a rarely diagnosed etiology of aborted SCD and myocardial infarction. Premortem diagnosis rests on angiographic evidence of flow in two lumens separated by a radiolucent flap of arterial intima.³ However, not all coronary artery dissections involve luminal intimal tears with a direct conduit between the true and false lumens. They may also present as intramural hematomas that may secondarily compress the true lumen.¹² These phenotypical angiographic variations likely represent different etiologies of the poorly characterized pathogenesis of SCAD. Postmortem histologic variability also supports this finding.¹ Given the spectrum of SCAD angiographic findings, the angiographer must have a high index of suspicion in order to make the appropriate diagnosis. Therefore, the diagnosis of SCAD must be considered in healthy young females without cardiac risk factors who present with acute coronary syndromes. Treatment should be highly individualized on a case-by-case basis. Given the inherent rarity of SCAD, there are no large-scale, randomized, controlled studies with outcome data to support any particular therapeutic modality. However, numerous case reports have been published utilizing the standard anti-ischemic therapies as well as novel modalities. Patients with active ischemia or failed medical management require revascularization. Thrombolytics have been used, but there is a theoretical concern for worsening of the intramural hematoma secondary to vasa-vasorum hemorrhage leading to further compression of the true lumen. Both percutaneous and surgical options are feasible but have inherent limitations as well. Percutaneous intervention may be technically challenging with regard to identifying the true lumen. In addition, there is potential for propagating the dissection or causing perforation. Surgical revascularization, likewise, can be technically difficult as the dissection may be more extensive than seen on angiography, thereby complicating target vessel and lumen identification. Isolated case reports regarding novel therapies have been published, including immunosuppressive agents and intramural hematoma resection. At this time, given the unclear pathophysiology, there are no guidelines on optimal therapy for SCAD. However, if one has a high index of suspicion for SCAD, we feel that if possible it is prudent to transfer to a facility that has catheterization capacity in order to confirm a dissection as thrombolytic therapy could propagate expansion of the false lumen. Most patients with multivessel/left main SCAD or failure of medical management are candidates for surgical revascularization. Percutaneous intervention is a viable option in well-localized lesions. Regardless of which revascularization modality is utilized, one must closely consider and monitor for the inherent limitations and complications of each. Medical management is reasonable in patients who are hemodynamically stable and without sign of ongoing ischemia. In summary, definitive therapeutic intervention is dictated by the patient's clinical status and the characteristics of the SCAD. This case is unique in many aspects. To our knowledge, this is only the second reported case of a patient with SCAD who survived an aborted SCD. Our patient experienced SCAD with minimal activity and not in the context of previously described associations. Angiographic findings were significant for a LAD dissection. After early diagnostic cardiac catheterization and conservative medical management, our patient experienced a complete recovery, returning to her pre-sudden cardiac death status without limitation. Our case suggests that medical management is a reasonable option in patients with single-vessel non-left main/proximal LAD artery SCAD. This article was reprinted with permission from the Journal of Invasive Cardiology 2005;17:E4,E6.