Introduction
Spontaneous coronary artery dissection (SCAD) is one of the leading causes of acute coronary syndrome (ACS) and myocardial infarction (MI). Its occurrence is predominantly linked to women, having reported sudden cardiac deaths in younger women. It is essential to note that SCAD is not a result of atherosclerotic response, trauma, or iatrogenic in origin. The pathophysiology behind its occurrence is attributed to the formation of an intramural hematoma (IMH) rather than any coronary artery blockage or thrombus development. Despite major advances in medicine, the diagnosis of SCAD still poses a significant challenge to many doctors. Oftentimes, the care and treatment administered to SCAD patients closely resemble that of an atherosclerotic coronary disease patient. Both these diseases are quite distinct in terms of their diagnosis, treatment plan, and outcome. Given that patients with SCAD are more likely to experience other serious consequences, an early and precise diagnosis is crucial to treating the condition without resorting to invasive coronary angiography. This article attempts to discuss the clinical presentation of SCAD and the advanced imaging tools used to identify it.
How Is SCAD Presented?
It is necessary to have a full understanding of the disease's symptoms before one can comprehend the clinical presentation of SCAD. Blood vessels that branch off to feed the heart with blood are known as coronary arteries. The blood pressure/flow rate is a measurement of the average speed at which blood flows through the lumen of the artery. This blood flow is fundamentally compromised in myocardial disorders that damage the coronary arteries, which can result in several consequences like stroke, myocardial infarction, or even sudden cardiac death from a lack of blood supply. When a condition has an atherosclerotic origin, it indicates that the thickening of the vessel wall or plaque accumulation has blocked the coronary arteries, causing a clot to form.
In the case of SCAD, there is no deteriorating change observed inside the lumen of the artery. However, there have been reports of an intramural hematoma developing spontaneously, which leads to the establishment of a false lumen. Thus, the forces give way to the compression of the actual lumen of the coronary artery, intensifying the same consequences that result in reduced blood flow. There may also be an intimal rupture in the wall of the coronary artery vessel, which allows blood from the genuine lumen to enter the false lumen and hampers blood flow. Determining whether the tear originated from the intramural hematoma or as a result of the compressive forces is a challenging task. The clinical presentation of SCAD mainly involves:
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Chest pain is the most common symptom observed.
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Elevated levels of cardiac enzymes, with a marked increase in troponin I level.
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About 2 to 5 percent of patients initially present with cardiogenic shock on the graph, ST-segment elevated MI is present in about 26 to 87 percent of SCAD patients, whereas 13 to 69 percent of patients present with non-ST segment elevated MI.
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About 3 to 11 percent of SCAD patients present with ventricular arrhythmias or sudden cardiac death.
How Is SCAD Diagnosed?
Misdiagnosis of SCAD has a favorable history, both in the past and in the present. One of the key reasons for this is that the symptoms of SCAD are similar to those of atherosclerotic coronary disorders. When a patient comes to the emergency room complaining of chest pain or discomfort, among other things, he or she is checked for any particular indicators of heart disease, like age, personal habits, high blood pressure, cholesterol, and lifestyle choices. The patient is returned home if none of the factors indicate that cardiac disease is present on the list. In this instance, the doctor's expertise proves to be invaluable. SCAD is not the same as coronary disorders, although presenting with symptoms similar to acute coronary syndrome. It requires an early diagnosis to prevent major problems that arise with a delay, and it has a separate set of diagnostic, therapeutic, and prognostic measures altogether.
1. Coronary angiography is the first-line imaging modality used to confirm SCAD. The angiographic traits include several unique attributes, including:
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Type 1 is seen in 29 percent of SCAD patients and is characterized by many radiolucent lumens or artery wall contrast staining.
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Another kind, which makes up roughly 67 percent of SCAD cases, has scattered stenosis of variable severity and duration.
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The third kind exhibits focal stenosis that resembles atherosclerosis; additional intracoronary imaging tests may be carried out to validate the SCAD diagnosis.
Despite being the gold standard imaging technique, coronary angiography is not favored by many due to its invasiveness. Several people who are extremely sensitive to iatrogenic infections are at risk for complications from the angiography.
2. When traditional coronary angiography is unable to reliably diagnose SCAD, intracoronary imaging is another imaging technique that is used. Intravascular ultrasonography and optical coherence tomography are two methods of intracoronary imaging that help provide a detailed image of the coronary artery dissection and can effectively depict the existence of an intramural hematoma or intimal tear around the vessel. However, because more sophisticated angiography methods have been developed recently for the identification of SCAD, this procedure is not as commonly employed as it formerly was.
3. A recently developed imaging technique called coronary computed tomography angiography (CCTA) is utilized to confirm SCAD. It is quite helpful in precisely examining the coronary arteries, and when used, the heart anatomy is evident. In addition to offering a well-rounded spatial resolution, the more recent scanners and technology also provide whole-heart imaging when necessary. Even with all of these developments, tiny distal coronary artery examination can still be difficult and beyond the resolution of available CT (computed tomography) scanners. For noninvasive follow-up of SCAD patients, particularly those with proximal or large-caliber coronary artery dissections, CCTA may be helpful.
Conclusion
Acute coronary syndrome and sudden cardiac death in women have been linked to spontaneous coronary artery dissection or SCAD. New developments in cardiac imaging have made it easier to diagnose and raise awareness of SCAD. Since the best short- and long-term care methods for women with SCAD differ significantly from those for women with atherosclerotic coronary disease, accurate imaging-based identification of SCAD is essential.
