Spontaneous Coronary Artery Dissection: A Review of Epidemiology, Pathophysiology and Principles of Management

Spontaneous coronary artery dissection and fibromuscular dysplasia: insights into recent developments

Spontaneous coronary artery dissection (SCAD), an uncommon cause of acute coronary syndrome, continues to be a poorly understood disease predominantly affecting females. It is characterized by an abrupt separation in the coronary arterial wall due to intramural bleeding. Fibromuscular dysplasia (FMD) is a non-atherosclerotic arteriopathy manifesting in medium and small-sized arteries. It is a concomitant disease found among SCAD patients. In some studies, FMD prevalence in SCAD patients ranges between 25%-86%, which can be explained through varying screening techniques or modalities. The potential association has been elucidated in some studies; notably, not only has a genetic link been recently delineated between SCAD and FMD, but there is data to suggest that FMD not only can predispose to SCAD but can also be a potential predictor of its recurrence. However, a clear-cut correlation between the two has still not been established due to conflicting reports in the literature. To further dive into its pathology, it is crucial to highlight the importance of systematic screening in SCAD in order to identify associated risk factors and to be used as a method of FMD detection in such patients. Together, the two pathologies pose unique challenges in understanding its pathophysiology, diagnosis and management, as there is no clear evidence of a definitive treatment plan for patients with SCAD and FMD. A potentially beneficial modality of management is physical exercise, which is currently understudied in the long-term approach to treatment for patients with concomitant SCAD and FMD. Limited research in this field brings disadvantages to the understanding of the association between these two diseases, in order to give rise to better management recommendations. This mini-review aims to highlight the recent developments in the association between SCAD and FMD, its potential genetic association and some insights in screening, diagnosis, and management.

Spontaneous Coronary Artery Dissection: An Updated Comprehensive Review

Spontaneous coronary artery dissection (SCAD) is defined as a non-iatrogenic, non-traumatic separation of the coronary artery wall, which has gained considerable recognition as an important cause of acute coronary syndrome. Despite the emerging evidence, it is still frequently missed and requires a high index of suspicion, as failure to accurately identify SCAD promptly could prove fatal. SCAD is most prevalent among middle-aged women, although it can also be found in men and postmenopausal women. Risk factors of SCAD include exogenous hormone use, physical and emotional stressors, pregnancy, and several inflammatory and connective tissue disorders. COVID-19 also contributes to the prevalence of SCAD. SCAD is classified into four main types based on the angiographic findings - type 1, type 2, type 3, and type 4. The gold standard for diagnosis is coronary angiography; however, intracardiac imaging is useful if diagnostic doubts persist. Despite the increasing recognition of this disease, there is a paucity in the guidelines on the management of SCAD. Management may be conservative, medical, or interventional. Cardiac rehabilitation is also necessary in the management of patients with SCAD. In light of the gaps in evidence, the authors aim to provide a comprehensive review of the existing literature, outlining the pathophysiology, classification, and, most importantly, the evidence and pitfalls circulating diagnosis, acute, and long-term management of SCAD.

A Case of Spontaneous Coronary Artery Dissection

Spontaneous coronary artery dissection (SCAD) is the development of an intramural hematoma that causes a false lumen to form, leading to occlusion and ischemia. It is a rare but separate pathologic cause of acute coronary syndrome, more commonly occurring in females and often associated with underlying vascular conditions. Definitive diagnosis requires invasive coronary angiography. Management is similar to that of myocardial infarction caused by atherosclerosis; however, the majority of SCADs are managed conservatively, as stenting often leads to worse outcomes. Diagnostic and management strategies are primarily based on consensus, with minimal randomized control trials or prospective analyses available to guide patient care.

A review of the risk and precipitating factors for spontaneous coronary artery dissection

Introduction

Spontaneous coronary artery dissection (SCAD) accounts for 1%-4% of cases of acute coronary syndrome (ACS). SCAD is caused by separation occurring within or between any of the three tunics of the coronary artery wall. This leads to intramural hematoma and/or formation of false lumen in the artery, which leads to ischemic changes or infarction of the myocardium. The incidence of SCAD is higher in women than in men, with a ratio of approximately 9:1. It is estimated that SCAD is responsible for 35% of ACS cases in women under the age of 60. The high frequency is particularly observed during pregnancy and in the peripartum period (first week). Traditional risk factors are rare in patients with SCAD, except for hypertension. Patients diagnosed with SCAD have different combinations of risk factors compared with patients who have atherosclerotic changes in their coronary arteries. We presented the most common so-called "non-traditional" risk factors associated with SCAD patients.

Risk factors and precipitating disorders which are associated with SCAD

In the literature, there are few diseases frequently associated with SCAD, and they are identified as predisposing factors. The predominant cause is fibromuscular dysplasia, followed by inherited connective tissue disorders, systemic inflammatory diseases, pregnancy, use of sex hormones or steroids, use of cocaine or amphetamines, thyroid disorders, migraine, and tinnitus. In recent years, the genetic predisposition for SCAD is also recognized as a predisposing factor. The precipitating factors are also different in women (emotional stress) compared with those in men (physical stress). Women experiencing SCAD frequently describe symptoms of anxiety and depression. These conditions could increase shear stress on the arterial wall and dissection of the coronary artery wall. Despite the advancement of SCAD, we can find significant differences in the clinical presentation between women and men.

Conclusion

When evaluating patients with chest pain or other ACS symptoms who have a low cardiovascular risk, particularly female patients, it is important to consider the possibility of ACS due to SCAD, particularly in conditions often associated with SCAD. This will increase the recognition of SCAD and the timely treatment of affected patients.

Spontaneous Coronary Artery Dissection: A Challenging Diagnosis

Spontaneous coronary artery dissection (SCAD) is a relatively uncommon cause of acute coronary syndrome, which is mainly reported in postpartum patients and patients without typical cardiac risk factors. Our case was a 58-year-old female with a history of diabetes, hypertension, and hyperlipidemia who presented with non-exertional crushing retrosternal chest pain and was found to have ST elevation in inferior leads. Immediate cardiac catheterization was suggestive of spontaneous dissection of the third obtuse marginal artery, which was managed conservatively. Clinical suspicion is crucial for SCAD diagnosis, as it might be difficult to distinguish between coronary artery occlusion and SCAD. Moreover, revascularization in SCAD can be associated with complications. Therefore, SCAD needs to be considered as a differential diagnosis not only in patients without cardiac risk factors but also in patients with known cardiac risk factors like our case.