Sudden cardiac death caused by a right coronary artery aneurysm complicated with acute myocardial infarction: a case report

Abstract

Coronary aneurysms are defined as coronary artery ectasia (CAE) more than 1.5 times the normal adjacent segment diameter or the maximum coronary artery diameter. Although most CAE patients are asymptomatic, some patients present with acute coronary syndrome (ACS), such as angina pectoris, myocardial infarction (MI), and even sudden cardiac death. Sudden death due to coronary artery dilatation is very rare. However, we report a case of a patient with aneurysm-like dilatation of both the left and right coronary arteries, with acute inferior ST segment elevation myocardial infarction and sudden death due to third-degree atrioventricular block. After cardiopulmonary resuscitation, the patient underwent emergency coronary intervention. After thrombus aspiration and intracoronary thrombolysis in the right coronary artery, the atrioventricular block returned to normal on the fifth day of hospitalization. Following anticoagulant therapy, coronary angiography was repeated and showed that the thrombus had disappeared. The patient is recovering well after active rescue at the time of writing.

Introduction

Coronary aneurysms are defined as coronary artery ectasia (CAE) more than 1.5 times the normal adjacent segment diameter or the maximum coronary artery diameter. ¹ Although most CAE patients are asymptomatic, some patients present with acute coronary syndrome (ACS), such as angina pectoris, myocardial infarction (MI), and even sudden cardiac death. ² Sudden death due to coronary artery dilatation is very rare. We report a case of a patient with aneurysm-like dilatation of both the left and right coronary arteries, with acute inferior ST segment elevation myocardial infarction and sudden death due to third-degree atrioventricular block.

Case presentation

A 55-year-old man was admitted to the emergency department following cardiopulmonary resuscitation after developing chest pain and loss of consciousness for 10 minutes. He began to have paroxysmal poststernal chest pain with palpitations and sweating 18 hours earlier without obvious inducement. Pain-relief medications were effective, and he was not treated in a hospital. Two hours before the loss of consciousness, owing to repeated syncope, he proceeded to our hospital for treatment. On the way to the hospital, he suddenly developed chest pain followed by loss of consciousness. After cardiopulmonary resuscitation, he was presented directly to the catheterization room from the ambulance for emergency surgery. He had a 10-year history of hypertension and smoked 60 packs of cigarettes (20 cigarettes per pack) per year. There was no known family history of coronary artery disease.

Electrocardiography (ECG) revealed sinus rhythm, third-degree atrioventricular block, borderline escape rhythm, and acute inferior wall ST segment elevation myocardial infarction (Figure 1a–d). The troponin concentration was 5.14 ng/mL (normal range: <0.03 ng/mL). Emergency coronary angiography showed that the left main coronary artery, anterior descending branch, and the circumflex branch were dilated (Figure 2a), and the right coronary artery was dilated in the proximal and middle segments, with interruption of blood flow in the middle segment (Figure 2b). A SION guidewire (Asahi Intecc, Akatsuki Cho, Japan) was introduced and advanced to the distal end of the right coronary artery. The shape of the guidewire suggested no obvious stenosis in the right coronary artery, and a thrombus was considered. Therefore, a suction catheter was placed; however, the thrombus could not be extracted. Middle and distal segment vasodilation with a large number of thrombi were found on angiography (Figure 2c). As the thrombus could not be extracted through the suction catheter, we injected 20 mg of recombinant human urokinase (Tasly Pharmaceutical Co., Ltd., Shanghai, China) through the suction catheter. After 30 minutes, a large thrombus was extracted. Repeat angiography showed that the blood vessels from the opening of the right coronary artery to the opening of the left ventricular posterior branch were markedly dilated, and some thrombus shadows were still visible (Figure 3a). After thrombus aspiration, contrast agent could be seen filling the posterior and descending branches on the left ventricle; however, a large number of thrombi were still visible in these blood vessels (Figure 3b). We administered a second injection (20 mg) of recombinant human urokinase through the suction catheter. After 30 minutes, repeat angiography showed that the right coronary artery was markedly dilated, and no stenosis was visible. A thrombus shadow was also seen in the left ventricular posterior branch, with a diameter of the largest dilation of approximately 11.25 mm (Figure 3c). After the operation, enoxaparin 6000 AxaIU was injected subcutaneously once every 12 hours for 3 consecutive days. Subsequently, enoxaparin was stopped, and rivaroxaban was initiated at a dose of 20 mg orally, once daily.

Figure 1.

Electrocardiography; (a) ECG showing sinus rhythm, third-degree atrioventricular block, borderline escape rhythm, and acute inferior wall ST segment elevation myocardial infarction. (b) ECG the day after surgery showing a return to sinus rhythm, with 2:1 atrioventricular block. (c) ECG on the third day after surgery showing a return to sinus rhythm, with second-degree type I atrioventricular block and (d) ECG on the fifth day after surgery showing sinus rhythm and no atrioventricular block.

Figure 2.

Angiogram showing that the left main coronary artery, anterior descending branch, and circumflex branch are dilated (a). The right coronary artery is dilated in the proximal and middle segments with interruption of blood flow in the middle segment (b) and Middle and distal segment vasodilation with a large number of thrombi are visible on angiography (c).

Figure 3.

Post-thrombectomy angiography; (a) The blood vessels from the opening of the right coronary artery to the opening of the left ventricular posterior branch are markedly dilated, and some thrombus shadows were still visible. (b) The left ventricular posterior branch and the posterior descending branch are visible; however, a large number of thrombi can still be seen in the blood vessels. (c) The right coronary artery is markedly dilated, and no stenosis is visible. A thrombus shadow is visible in the left ventricular posterior branch, and the diameter of the largest dilation is approximately 11.25 mm and (d) The right coronary artery is markedly dilated, the distal small vessels are visible, and no thrombi are visible.

During the afternoon of the day after surgery, the patient's ECG returned to sinus rhythm, with 2:1 atrioventricular block (Figure 1b). On the morning of the third day, sinus rhythm was evident on the patient's ECG, with second-degree type I atrioventricular block (Figure 1c). On the morning of the fifth day, the patient's ECG showed sinus rhythm with no atrioventricular block (Figure 1d). During the entire treatment, there was no chest pain, chest tightness, or syncope. On the 13th day, coronary angiography showed that the entire right coronary artery, including the branch vessels, was markedly dilated, and the distal small vessels were visible, without thrombi (Figure 3d).

There are many reasons for coronary artery aneurysm, such as Kawasaki disease, connective tissue disease, infection, and coronary artery stenting.^3–5 In this patient, we also evaluated the concentrations of thyroid hormone, antinuclear antibody, antineutrophil cytoplasmic antibody, and anticardiolipin antibody; all results are normal. The patient had no other medical, surgical, or traumatic history, and he did not remember febrile childhood disease consistent with childhood Kawasaki disease. We surmised that the aneurysm was idiopathic. The patient was discharged with anticoagulants and antihypertensive drugs and advised to stop smoking.

Discussion

The incidence of coronary aneurysm ranges from 0.3% to 5.3%. ⁶ Studies have shown that approximately 50% of CAEs are caused by atherosclerosis, 20% to 30% by congenital diseases, and 10% to 20% by inflammatory or connective tissue diseases, such as Kawasaki disease, Takayasu arteritis, lupus, or rheumatoid arthritis. ⁷ The complications associated with coronary aneurysmal dilatation are thrombosis and distal embolism, and rupture and vasospasm, which lead to acute coronary syndrome, arrhythmia, or sudden death. ⁸ Our patient had aneurysmal dilatation of the right coronary artery with massive thrombosis, leading to acute inferior ST segment elevation myocardial infarction and third-degree atrioventricular block. The loss of vision and sudden death in our patient may have been related to the third-degree atrioventricular block.

Myocardial infarction in patients with CAE may be due to atherosclerotic coronary artery disease or to aneurysmal thrombosis secondary to non-laminar flow arrest that is unrelated to plaque rupture. ⁹

Drug therapy for CAE comprises antiplatelet drugs and medications to address cardiovascular risk factors, such as hypertension, diabetes, and hyperlipidemia, in accordance with a small case series. A previous recent study suggested that anticoagulant therapy may have advantages in patients with acute coronary syndrome complicated by CAE. ¹⁰ In patients with acute coronary syndrome caused by CAE, the focus is on restoring blood flow. Owing to the high burden of related thrombosis, thrombus aspiration is often performed as additional therapy. ¹¹ Our patient had a large thrombus in the dilated right coronary artery, and thrombus aspiration was incomplete. Therefore, we performed intracoronary thrombolysis, and right coronary artery blood flow reached thrombus in myocardial infarction (TIMI) level 3, with only a small amount of the thrombus remaining. After the blood flow in the patient’s right coronary artery recovered, the ECG gradually recovered from third-degree atrioventricular block to the absence of atrioventricular block.

Some investigators have used rivaroxaban at low doses (15 mg once daily) in similar cases. ¹² Other surgical options comprise aneurysm ligation, resection, or bagged implant transplantation. ¹³

Conclusion

We described a case of right coronary artery aneurysm with acute inferior myocardial infarction resulting in sudden death associated with third-degree atrioventricular block. After cardiopulmonary resuscitation, the patient underwent emergency coronary intervention. After thrombus aspiration and intracoronary thrombolysis in the right coronary artery, atrioventricular block returned to normal on the fifth day of hospitalization. Following anticoagulant therapy, repeat coronary angiography confirmed that the thrombus had disappeared. The patient is recovering well after active rescue at the time of writing. The combination of intracoronary thrombus aspiration and thrombolysis in such patients is a possible therapeutic option, and in this case, a good therapeutic effect was achieved. This study complies with the CARE reporting guidelines. ¹⁴