Spontaneous coronary artery dissection (SCAD), defined as separation of the layers of the coronary wall unrelated to trauma, iatrogenesis, or atherosclerosis, often occurs in young women without cardiovascular risk factors.¹ First described almost a century ago, it was poorly understood for some time, known only to be associated with the peripartum and pregnancy periods.² SCAD is a rare cause of acute coronary syndrome (ACS), and despite technological advances in invasive or non-invasive imaging tests increasing our understanding of its pathophysiology and treatment, it remains underdiagnosed.¹³ This report describes the case of an ACS patient without obstructive lesions on coronary angiography in which coronary computed tomography angiography (CCTA) was an indispensable tool in the diagnosis of SCAD with an unusual location, highlighting its growing importance based on the current scientific literature.

A white 55-year-old postmenopausal and hypertensive woman who regularly used hydrochlorothiazide and enalapril went to the emergency room with typical chest pain after emotional stress. A physical examination revealed no significant findings, including asymmetric peripheral pulses, blood pressure levels, or dermatological lesions. Electrocardiography (ECG) showed extensive anterior wall ST-segment elevations (Figure 1). The patient was clinically treated for ACS and referred to a reference hospital for primary angioplasty.

On admission, she presented complete improvement in symptoms and resolution of ST-segment elevation on ECG but new anterior wall T-wave inversion suggestive of ischemia in this territory. Myocardial necrosis markers were elevated, with the ultrasensitive troponin T level increasing from 17.00 to 68.00 pg/mL (reference range, <14.00 pg/mL). Early (24-hour) coronary angiography revealed no significant obstructive lesions in the coronary arteries, with normal ventriculography and preserved systolic function (Figure 2). By pragmatic definition, the patient was diagnosed with myocardial infarction and nonobstructive coronary arteries (MINOCA).

During the etiological investigation, computed tomography angiography of the thoracic aorta and coronary arteries showed parietal thickening involving the segments proximal and in the middle of the anterior descending artery (ADA) (Figure 3), suggesting an intramural hematoma resulting from a coronary artery dissection.

The patient remained stable during hospitalization, with favorable progression under conservative treatment. She was discharged from the hospital after five days with dual antiplatelet and beta-blocker therapy in addition to the antihypertensive drugs previously used.

SCAD is an important cause of acute myocardial infarction in women with few cardiovascular risk factors and should be considered in cases in which MINOCA is the initial diagnosis.⁴ The prevalence of SCAD remains unknown due to its underdiagnosis, but recent studies reported SCAD in 1–4% of coronary angiographies performed for acute chest pain.⁵ Approximately 90% of cases occur in women, in whom SCAD accounts for more than one third of ACS cases in patients under the age of 50 years or associated with pregnancy.¹

One of the most accepted theories in etiopathogenesis is the weakening of the coronary artery wall layers, with vasa vasorum rupture, bleeding into the false lumen, and consequent formation of intramural hematoma between the intima, media, or adventitia, obstructing blood flow and causing myocardial injury.¹³

The most frequently related condition is fibromuscular dysplasia, with a prevalence of approximately 80% in recent studies.⁶ This condition predominates in women in the gestational period or who are using contraceptive or fertility drugs, suggesting hormonal influence on vascular connective tissue and the consequent fragility of the middle arterial layer.² Emotional disorders such as depression, anxiety, and migraine are associated with this higher prevalence.⁷

Since it typically presents as chest pain, diagnosing SCAD is challenging. Like other ACS etiologies, it also causes biomarker and electrocardiographic changes, including ST-segment elevation and ventricular arrhythmias, making it difficult to clinically differentiate it from an atherothrombotic event.⁸

Thus, the use of coronary angiography is essential to its classification as described by Saw into type 1 (contrast visualization on the arterial wall), type 2 (smooth and diffuse stenosis with a medial-distal predominance in the vessel), and type 3 (focal stenosis similar to atherosclerosis differentiated by intracoronary imaging).⁹ Type 2 is the most common, being found in approximately two-thirds of cases, predominantly in the medial-distal segment of the ADA. This report describes the involvement of the proximal segment, which occurs in less than 10% of cases.¹

Intravascular coronary imaging, such as optical coherence tomography and intravascular ultrasound, are used in cases of diagnostic uncertainty or as guides for invasive targeted treatments.¹⁰ However, its use is limited by its high cost and limited availability.

Technological advances in non-invasive imaging tests have consolidated this modality in the etiological investigation of ACS. Current literature reviews have highlighted the role of CCTA in SCAD, stressing the fundamental importance in parietal and extra-coronary evaluations and its essential nature for diagnosis in some cases.¹¹ Recent retrospective studies demonstrated that the most common findings were abrupt or conical luminal stenosis and intramural hematoma, but others findings such as dissection flap, total lumen occlusion, bridging, and tortuous coronary have also been described.^12,13 One of the most relevant advantages is to minimize the risk of iatrogenesis as in invasive angiography.²

However, a normal CCTA does not exclude the diagnosis of SCAD, as distal segments smaller than 1.5 mm in diameter may be beyond the method’s resolution.¹¹

Therapeutic management is mostly conservative and supportive since more than 70% of cases progress with regression of angiographically visible lesions.⁵ In the long term, beta-blockers play a role in reducing recurrence, and dual antiplatelet therapy consisting of aspirin and clopidogrel for up to one year is recommended by specialists.⁶ Renin angiotensin system antagonists are indicated in cases of systolic dysfunction or hypertension, while statins are used for preexisting dyslipidemia or concomitant atherosclerotic disease.¹

Although the survival rate is close to 100%, half of patients experience an important correlation with a major cardiovascular event in the following decade, 35% due to SCAD, as well as depression and nonischemic chest pain.⁶ As recurrence is common, periodic follow-up is necessary and non-invasive tests, such as CCTA, are viewed with optimism in this scenario, with little evidence presented in the literature to date.^2,7

Therefore, the diagnosis of SCAD should be suspected in cases of ACS without obstructive lesions on coronary angiography, especially in young women with few or no cardiovascular risk factors. This study examined the growing importance of CCTA in this scenario, corroborating the most recent scientific evidence and highlighting the value of non-invasive imaging methods as diagnostic tools.