Cardiac arrest due to an anomalous aortic origin of a coronary artery: are older patients really safe?

The authors report a rare case of successful Advanced Life Support in the context of cardiac arrest due to the presence of an anomalous aortic origin of the right coronary artery in a 49-year-old patient. The patient was admitted due to chest pain and dyspnea, with rapid evolution of pulseless ventricular tachycardia and cardiopulmonary arrest. Acute myocardial infarction was considered, and in the absence of a hemodynamic laboratory in the hospital, thrombolysis was performed. Subsequently, coronary angiography revealed no angiographic lesions in the coronary arteries and an anomalous right coronary artery originating from the opposite sinus of Valsalva. Coronary computed tomography angiography confirmed this finding and determined the course between the pulmonary artery and the aorta. The patient underwent cardiac surgery with a bypass graft to the right coronary artery, with no recurrent episodes of arrythmia.

The authors report a rare case of successful Advanced Life Support in the context of cardiac arrest due to the presence of an anomalous aortic origin of the right coronary artery in a 49-yearold patient. The patient was admitted due to chest pain and dyspnea, with rapid evolution of pulseless ventricular tachycardia and cardiopulmonary arrest. Acute myocardial infarction was considered, and in the absence of a hemodynamic laboratory in the hospital, thrombolysis was performed.
Subsequently, coronary angiography revealed no angiographic lesions in the coronary arteries and an anomalous right coronary artery originating from the opposite sinus of Valsalva. Coronary computed tomography angiography confirmed this finding and determined the course between the pulmonary artery and the aorta. The patient underwent cardiac surgery with a bypass graft to the right coronary artery, with no recurrent episodes of arrythmia. which dilate during exercise and thus compress the coronary artery; an acute angle of the initial trajectory of the coronary artery; ostial abnormalities; an intramural course (course within the aortic wall prior to exiting the mediastinum); and vessel spasms and intussusception of the anomalous artery. (1,2,(9)(10)(11) An anomalous origin of the right coronary artery from the left coronary sinus is frequently associated with exercise-related sudden death. (1) Diagnosis of an AAOCA may be suggested with transthoracic or transesophageal echocardiography by abnormal biphasic flow in the left ventricular outflow tract. (1) Coronary angiography, coronary computed tomography angiography (CCTA) and cardiac magnetic resonance (CMR) allow direct visualization of an AAOCA, establishing the diagnosis. (1) The preferred method, due to its noninvasive nature and acceptable availability, in addition to its precise demonstration of the anatomy and course of the anomalous vessel, is CCTA. (4,12,13) The treatment of asymptomatic patients, especially those with an anomalous right coronary artery from the left sinus of Valsalva with an interarterial or intramural course, is controversial among authors. (11) If associated with symptoms (chest pain or syncope) or documented ischemia during stress tests and/or inducible myocardial perfusion abnormalities on advanced imaging, surgical correction is recommended according to the guidelines for the management of adults with congenital heart disease published in 2008 by the American College of Cardiology/American Heart Association (class indication I, evidence level B). (2,14,15) Sudden death is rare in individuals older than 30 years. In this population, the risk associated with surgery exceeds the potential benefits, and surgery should be avoided in both asymptomatic and symptomatic individuals unless ischemia can be documented. (2) Surgical interventions, most commonly coronary translocation, are safe, with a low incidence of mortality and postoperative complications. (16,17) Coronary artery bypass grafts should be avoided, especially in younger populations, given the potential for competitive flow from native vessels to cause graft failure. There are a few reports of percutaneous coronary intervention of anomalous coronary arteries with good results, even in critically ill newborns for whom there were no other treatment options. However, the insertion of stents into coronary arteries in young patients can be problematic. (5,14)

CASE DESCRIPTION
The authors present the case of a 49-year-old male patient. He was previously asymptomatic and had no relevant personal background or chronic medication. He was a current smoker but denied either alcoholic or toxic consumption. He was admitted to the emergency room due to oppressive chest pain and dyspnea that started half an hour before. Five days prior to hospital admission, the patient reported a similar episode of oppressive chest pain that started during a walk and lasted for approximately 30 minutes after resting.
Upon arrival at the emergency room, the patient was prostrated and cyanotic, with an increased respiratory rate and hypoxia despite a high debit oxygen mask. The patient evolved rapidly to cardiopulmonary arrest, so advanced life support maneuvers were initiated, and the patient was orotracheally intubated and invasively ventilated. Blood gas analysis showed severe metabolic acidosis with hyperlacticaemia (pH = 6.87; partial pressure of carbon dioxide -PaCO 2 -105mmHg, partial pressure of oxygen -PaO 2 -120mmHg, bicarbonate -HCO 3 -13.9, lactate 13.5mmol/L). An electrocardiogram revealed R-R regular wide complex tachycardia (170/minute) with right axis deviation, suggestive of ventricular monomorphic tachycardia. Since there was no response to advanced life support maneuvers with persistent pulseless ventricular tachycardia, and considering the patient's complaints of chest pain, acute myocardial infarction was considered, and thrombolysis with alteplase was performed in the absence of a hemodynamic laboratory in the hospital. After recovery to spontaneous circulation, an electrocardiogram showed sinus rhythm, 90/minute, biphasic T between V3 and V5.
Thrombolysis was complicated by bleeding at the central venous catheter puncture site and abundant hematemesis. Upper digestive endoscopy was performed, showing bleeding of the gums, digested blood and clots in the stomach. Due to active bleeding, the case was discussed in hemodynamic laboratory, and coronary angiography was delayed until clinical stabilization and bleeding cessation occurred.
Three days after admission, the patient progressively improved, allowing for orotracheal extubation. Brain computed tomography was unremarkable. A ventilation-perfusion scan was performed, excluding pulmonary embolism. Coronary angiography showed coronary arteries with no relevant angiographic lesions and a right coronary artery with an abnormal origin at the left coronary sinus (Figure 1), followed by CCTA that confirmed the abnormal origin of the right coronary artery from the left coronary sinus coursing between the pulmonary artery trunk anteriorly and the aorta posteriorly -an interarterial course with an extension of 18mm; there was no evidence of an intramural course or atherosclerotic coronary disease, with a calcium score 0 (Figures 2 and 3). Cardiac magnetic resonance was unremarkable -no late enhancement was detected.

DISCUSSION
The most likely causes of cardiopulmonary arrest in the present case are acute coronary syndrome and massive pulmonary embolism. With only mild elevation of hstroponin in a clinical setting of cardiorespiratory arrest, the absence of lesions on coronary angiography, even after thrombolysis, and the absence of late enhancement on cardiac magnetic resonance make the hypothesis of myocardial infarction unlikely. Although fibrinolysis is only indicated in patients presenting early and when anticipated ST elevation myocardial infarction diagnosis and the mediated reperfusion time is more than 120 minutes -it was performed in this case due to the inexistence of a hemodynamic laboratory in our hospital and the clinical instability that did not allow transportation to the primary percutaneous coronary intervention center. Prolonged resuscitation may increase bleeding risks and may be a relative contraindication to fibrinolysis; however, it is important to weigh the potentially life-saving effect of fibrinolysis against the potentially life-threatening side effects. This must also be weighed against the risks and benefits of delayed primary percutaneous coronary intervention. The hypothesis of a massive pulmonary embolism was also excluded in the absence of dilation and dysfunction of the right ventricle on the transthoracic echocardiogram and the absence of perfusion defects on the ventilation-perfusion scan (although it was performed after thrombolysis). Other causes, such as electrolyte disturbances, drug consumption, myocarditis and hypertrophic cardiomyopathy, were also excluded. In this case, CCTA confirmed the presence of an anomalous right coronary artery with an interarterial course. Based on the clinical history and the results of complementary diagnostic exams, the diagnosis of an abnormal coronary origin responsible for cardiorespiratory arrest was considered, and the patient was referred for cardiac surgery. He successfully underwent myocardial revascularization surgery with a bypass from the left internal mammary artery to the right coronary artery. After cardiac surgery, the patient stayed clinically stable, with no recurrent episodes of arrythmia.
Despite an extensive literature review, there appear to be just two documented cases in the European Heart Journal and British Medical Journal of survivors of cardiac arrest due to an anomalous right coronary artery documented by CCTA; these patients proceeded to undergo successful surgical correction. (18,19) The vast majority of other documented cases are from necropsy case series.