Spontaneous coronary artery dissection and associated myocardial bridging: Current evidence from cohort study and case reports

Angiographic patterns in spontaneous coronary artery dissection: novel diagnostic insights

INTRODUCTION

Spontaneous coronary artery dissection (SCAD) is a rare but well-recognized cause of acute coronary syndrome, especially important in women. Invasive coronary angiography (ICA) is the fundamental diagnostic technique for the confirmation of SCAD. Knowing the angiographic patterns suggestive of SCAD is essential for the correct identification of patients with this entity.

AREAS COVERED

In this narrative review, the main angiographic characteristics of SCAD lesions as detected by ICA are presented and discussed.

EXPERT OPINION

In addition to the specific angiographic classification of SCAD, several authors have described complementary angiographic patterns suggestive of SCAD. Knowledge and correct identification of these angiographic patterns is essential for the correct diagnosis of patients with clinical suspicion of SCAD.

Pathophysiology and diagnostic pathway of myocardial infarction with non-obstructive coronary arteries

Myocardial infarction with non-obstructive coronary arteries (MINOCA) is a heterogeneous and diverse disease entity, which accounts for about 6 % of all acute myocardial infarction (AMI) cases. In patients with chest pain and acute myocardial injury detected by a highly sensitive troponin assay, the absence of epicardial coronary stenosis of 50 % or greater on angiography leads to the working diagnosis of MINOCA. The updated JCS/CVIT/JCC 2023 Guideline described MINOCA as a new disease concept and recommended a multimodality approach to uncovering the underlying causes of MINOCA. Cardiac magnetic resonance (CMR) is useful in not only making a definite diagnosis of MINOCA, but also excluding non-ischemic causes that mimic AMI such as takotsubo cardiomyopathy and myocarditis. Meanwhile, intracoronary imaging, particularly optical coherence tomography (OCT), enables us to evaluate precisely intracoronary morphological alterations including plaque disruption and spontaneous coronary artery dissection which are not revealed by angiographic findings alone. Recent studies have shown that an initial workup with the combination of CMR and OCT could provide a definite diagnosis in a significant percentage of patients suspected of MINOCA. Consecutively, patients with inconclusive results of a series of CMR and OCT implementation are eligible for assessing the potential for coronary functional abnormalities or blood coagulopathy as another factor involved in the development of MINOCA. Although uncovering the pathogenesis of MINOCA might be essential for establishing an individualized treatment approach, significant knowledge gaps in terms of secondary prevention strategies for MINOCA focusing on the improvement of long-term prognosis remain to be overcome. In this review, we summarize our current understanding of MINOCA and highlight contemporary diagnostic approaches for patients with suspected MINOCA.

Assessment of extra-coronary peripheral arteriopathy in spontaneous coronary dissection: state of the art in non-invasive imaging techniques and future perspectives

Spontaneous coronary artery dissection (SCAD) has been recognized as an important cause of acute coronary syndrome in women ≤ 50 years old, and up to 43% of pregnancy-associated myocardial infarction. SCAD has a strong association with extra-coronary arteriopathies, including either more common entities such as dissections, intracranial or other aneurysms, and extra-coronary and coronary arterial tortuosity or less common inherited vascular disorders such as Ehlers-Danlos syndrome, Marfan syndrome, and Loeys-Dietz syndrome, leading to the conclusion that systemic arterial disorders may underlie SCAD. Fibromuscular dysplasia is the most common extra-coronary vascular abnormality identified among these patients, also sharing a common genetic variant with SCAD. The American Heart Association, in a scientific statement regarding the management of SCAD, recommends that patients with SCAD should undergo additional evaluation with imaging techniques including either computed tomography angiography (CTA) or magnetic resonance angiography (MRA). MRA has been shown to have sufficient diagnostic accuracy in identifying extra-coronary arterial abnormalities, almost equal to CTA and conventional angiography. The aim of this review is to appraise the most recent important evidence of extra-coronary arteriopathy in the setting of SCAD and to discuss the strengths and weaknesses of various non-invasive imaging methods for screening of extra-coronary arteriopathies in patients with SCAD.

MINOCA Associated with a Myocardial Bridge: Pathogenesis, Diagnosis and Treatment

Myocardial bridging (MB) is the most frequent congenital coronary anomaly characterized by a segment of an epicardial coronary artery that passes through the myocardium. MB is an important cause of myocardial ischemia and is also emerging as a possible cause of myocardial infarction with non-obstructed coronary arteries (MINOCA). There are multiple mechanisms underlying MINOCA in patients with MB (i.e., MB-mediated increased risk of epicardial or microvascular coronary spasm, atherosclerotic plaque disruption and spontaneous coronary artery dissection). The identification of the exact pathogenetic mechanism is crucial in order to establish a patient-tailored therapy. This review provides the most up-to-date evidence regarding the pathophysiology of MINOCA in patients with MB. Moreover, it focuses on the available diagnostic tools that could be implemented at the time of coronary angiography to achieve a pathophysiologic diagnosis. Finally, it focuses on the therapeutic implications associated with the different pathogenetic mechanisms of MINOCA in patients with MB.

Spontaneous coronary artery dissection: the emerging role of coronary computed tomography

Spontaneous coronary artery dissection (SCAD) is a cause of acute coronary syndrome and myocardial infarction, more frequent among young women. Invasive coronary angiography (ICA) is the gold standard for the diagnosis of SCAD, although the risk of propagating dissection flap is considerable. Therefore, coronary computed tomography angiography (CCTA) is an emerging alternative modality to diagnose SCAD with the advantage of being a non-invasive technique. Clinicians should be aware of the predisposing conditions and pathophysiology to raise the pre-test probability of SCAD and select the most appropriate diagnostic tools. In recent times, improvements in spatial and temporal resolution and the use of semi-automated software providing quantitative assessment make CCTA a valid alternative to ICA also for the follow-up. Moreover, CCTA may be helpful to screen and evaluate extra-coronary arteriopathies closely related to SCAD. In this review, we illustrate the current and the potential role of CCTA in the diagnosis of SCAD, highlighting advantages and disadvantages of this imaging modality compared to ICA.

The role of cardiac rehabilitation in improving cardiovascular outcomes

Cardiac rehabilitation is a complex intervention that seeks to improve the functional capacity, wellbeing and health-related quality of life of patients with heart disease. A substantive evidence base supports cardiac rehabilitation as a clinically effective and cost-effective intervention for patients with acute coronary syndrome or heart failure with reduced ejection fraction and after coronary revascularization. In this Review, we discuss the major contemporary challenges that face cardiac rehabilitation. Despite the strong recommendation in current clinical guidelines for the referral of these patient groups, global access to cardiac rehabilitation remains poor. The COVID-19 pandemic has contributed to a further reduction in access to cardiac rehabilitation. An increasing body of evidence supports home-based and technology-based models of cardiac rehabilitation as alternatives or adjuncts to traditional centre-based programmes, especially in low-income and middle-income countries, in which cardiac rehabilitation services are scarce, and scalable and affordable models are much needed. Future approaches to the delivery of cardiac rehabilitation need to align with the growing multimorbidity of an ageing population and cater to the needs of the increasing numbers of patients with cardiac disease who present with two or more chronic diseases. Future research priorities include strengthening the evidence base for cardiac rehabilitation in other indications, including heart failure with preserved ejection fraction, atrial fibrillation and congenital heart disease and after valve surgery or heart transplantation, and evaluation of the implementation of sustainable and affordable models of delivery that can improve access to cardiac rehabilitation in all income settings.

The Self Sabotaging Vessel: A Case Report and Literature Review of Spontaneous Coronary Artery Dissection

Spontaneous coronary artery dissection (SCAD) is a very rare cause of acute coronary syndrome. Despite the recent advances in the management of cardiovascular diseases, the diagnoses and management of SCAD remain a dilemma. It has been described to majorly affect females of childbearing age, immediately post-partum or on oral contraceptives. Recent cases have also identified underlying connective tissue disease as a risk factor. Since its discovery, only a limited number of cases affecting males have been reported in the literature. This makes our case unique. In this, we present a 31-year-old male without any traditional risk factors who presented with atypical chest pain. Electrocardiogram showed ST-segment changes with echocardiogram revealing apical left ventricular akinesis. A diagnostic left heart catheterization showed multiple lumens in the distal left anterior descending artery (LAD). The patient was managed conservatively and discharged home on guideline-directed medical therapy.

Coexistence of Spontaneous Coronary Artery Dissection, Takotsubo Cardiomyopathy, and Myocardial Bridge

We report a case of spontaneous coronary artery dissection located next to a myocardial bridge in a patient with concomitant takotsubo cardiomyopathy. A fusion image with multidetector-row computed tomography and single-photon emission computed tomography played an important role in the diagnosis of these lesions. (Level of Difficulty: Advanced.)

The Young Heart Tears Easily Apart: A Case Report of Spontaneous Coronary Artery Dissection

Spontaneous coronary artery dissection (SCAD) is a rare cause of acute coronary syndrome (ACS), seen mostly in young females. The rarity and limited knowledge of the disease make its management challenging. Prompt diagnosis of the condition is extremely important to decrease both long- and short-term complications. Treatment options depend on hemodynamic stability and the location of the dissection- with more distal lesions treated more conservatively as opposed to proximal lesions which are treated with percutaneous coronary intervention (PCI) or coronary artery bypass graft (CABG). The following are the two cases with different presentation, management and outcomes.

Our first patient was a 35-year-old woman with no medical history who presented with acute, anginal pain, diaphoresis and palpitations. She was hemodynamically stable on presentation, with work-up significant for electrocardiogram (ECG) with sinus bradycardia, ST elevation in leads V1-V6, and elevated troponin level of 4 ng/ml. There was no evidence of a pulmonary embolism on computed tomography (CT) of the chest. A coronary angiogram showed 100% dissection of the proximal to mid-left anterior descending (LAD) artery. Attempts to place a stent in the proximal to mid LAD were unsuccessful as the true lumen of the LAD was not accessible. The patient became hemodynamically unstable, and an emergent CABG was done, restoring blood flow. The patient recovered during her hospital stay and was discharged with dual antiplatelet therapy (DAPT), beta-blockers, and atorvastatin.

The second patient was a 28-year-old woman, with a history of hypertension who presented with anginal chest pain. Workup showed ECG with minimal ST elevations in anteroseptal leads, with elevated troponin level to 0.71 ng/ml. Coronary angiogram showed 40-50% stenosis of the mid LAD with an aneurysmal segment. An echocardiogram showed no evidence of wall motion abnormalities, and she had a normal left ventricular ejection fraction (LVEF). She was discharged home the next day, on medical management. After two days, she returned to the hospital with similar complaints, with work-up significant for ECG with non-specific ST-T abnormality, and troponin level which peaked at 2.22 ng/ml. She was started on a heparin drip, and a repeat left heart catheterization revealed type 2 dissection of the mid to distal LAD, with intravascular ultrasound showing a fractional flow reserve of 0.76. She was discharged home on DAPT, beta-blocker, calcium channel blocker (CCB), and atorvastatin, with close cardiology follow up.

These two cases highlight the importance of keeping in mind the possibility of SCAD, especially when relatively healthy young women present with anginal symptoms. Early diagnosis of the condition and prompt management are extremely important to ensure favourable outcomes. The two cases also describe the coronary angiogram findings in SCAD, and the different strategies employed in the management of this condition.

Bridging the Gap in a Rare Cause of Angina

Myocardial bridging occurs when coronary arteries run intramurally. Episodes of tachycardia can cause a dynamic obstruction that extends into diastole, compromising coronary filling time, and subsequently leading to ischaemia. Myocardial ischaemia, acute coronary syndrome, coronary spasm, myocardial stunning, arrhythmia, takotsubo cardiomyopathy, and sudden cardiac death have all been reported with bridging. Atherosclerotic plaques develop proximally in the bridge due to low shear stress and high oscillatory wall-flow. Factors affecting atherosclerotic build-up include disrupted flow patterns (particularly flow recirculation, which exacerbates LDL internalisation), cell adhesion and monocyte adhesion to the endothelium. Endothelial health depends on arterial flow patterns, given that the vessel reacts differently to various flow types, as confirmed in 3D simulations. Medication is the first-line therapy, while surgical de-roofing and coronary bypass are reserved for severe stenosis. Distinguishing physiological arterial compression from pathological stenosis is essential. Deeper bridges correlating with recurrent angina with an instantaneous wave-free ratio ≤0.89 or fractional flow reserve ≤0.80 are treated.

Role of Coronary CT Angiography in Spontaneous Coronary Artery Dissection

Spontaneous coronary artery dissection (SCAD) is more common than previously thought and is present in up to 4% of patients presenting with acute coronary syndrome. SCAD predominantly occurs in relatively young women and is an important cause of myocardial infarction in young patients without traditional risk factors of atherosclerotic coronary artery disease. There have been substantial improvements in spatial and temporal resolution and reduction in ionizing radiation dose with new generation scanners. The risk of dissection propagation with an invasive coronary angiogram, improved CT scanner parameters, and predominantly conservative management of SCAD make coronary CT angiography a useful noninvasive imaging modality for the assessment of SCAD. © RSNA, 2020.