Spontaneous coronary artery dissection overview
Spontaneous Coronary Artery Dissection Microchapters
Synonyms and Keywords: SCAD
Spontaneous coronary artery dissection (SCAD) is a rare, but under recognized cause of acute coronary syndrome and sudden cardiac death, which predominantly affects young, healthy women with few to no traditional cardiovascular risk factors.
The first case of spontaneous coronary artery dissection was described by Pretty in 1931.
Spontaneous coronary artery dissection can be classified based on angiographic appearance into type 1 (evident arterial wall stain with multiple radiolucent lumens), type 2 (diffuse smooth stenosis of varying severity), and type 3 lesions (focal or tubular stenosis mimicking atherosclerosis).
At present the pathophysiology of non-atherosclerotic spontaneous coronary artery dissection (NA-SCAD) continues to be poorly understood due to the rarity of this condition and its heterogeneous pathology. Although intimal tear or bleeding of vasa vasorum with intramedial hemorrhage seems to be most probable reasons, the exact underlying mechanism is still unknown.
The exact etiology of spontaneous coronary artery dissection remains elusive; however, fibromuscular dysplasia and takotsubo cardiomyopathy have been considered as the potential cause of spontaneous coronary artery dissection.
Differentiating Spontaneous Coronary Artery Dissection from Other Conditions
Spontaneous coronary artery dissection should be differentiated from other causes of acute coronary syndrome. intracoronary imaging such as intravascular ultrasound (IVUS) and optical coherence tomography (OCT) may be required for establishing a definitive diagnosis.
Epidemiology and Demographics
The annual incidence of spontaneous coronary artery dissection is estimated at 0.26 per 100,000 persons (0.33 in women and 0.18 in men), corresponding to approximately 800 new cases per year in the United States. The true prevalence of spontaneous coronary artery dissection in the general population remains unknown; however, retrospective angiographic registries have reported a SCAD detection rate of 0.1 to 1.1% among all coronary angiograms performed.
Multiple risk factors and precipitating stressors have been identified for SCAD, including fibromuscular dysplasia (FMD), connective tissue disorders, systemic inflammatory disorders, pregnancy and the peripartum state, hormonal therapy, and extreme physical exertion and/or emotional stress.
Natural History, Complications and Prognosis
Based on the limited outcomes data, SCAD survivors typically have a good long-term prognosis; however, there is an increased risk for recurrent SCAD events as well as other major cardiovascular events.
Heightened awareness along with advances in intracoronary imaging techniques have led to an increase in the number of SCAD cases reported antemortem.
History and Symptoms
The hallmark symptom of spontaneous coronary artery dissection (SCAD) is angina pectoris, similar to to other acute coronary syndromes, that may radiate to the jaw or left arm. SCAD should be suspected with these symptoms in relatively young women, especially those in postpartum status. However, many patients do not have typical risk factors of coronary artery disease. Patients are typically asymptomatic on follow up.
Electrocardiogram findings vary according to the coronary flow-limitation by the dissection flap or intramural haematoma. There can be no changes in ECG in some cases. In other cases ecg may show any of changes.
Other Imaging Findings
Other Diagnostic Studies
In the majority of cases, conservative medical management is the optimal treatment strategy; however, based on the patient's clinical status and anatomy of the coronary dissection, revascularization with percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG) may be warranted.
There are no specific guidelines regarding the optimal management of spontaneous coronary artery dissection. Based on the clinical and angiographic scenario, treatment options include conservative medical regimens similar to that for acute coronary syndrome, percutaneous coronary intervention, and/or coronary artery bypass surgery.
Percutaneous Coronary Intervention
Cost-Effectiveness of Therapy
Future or Investigational Therapies
Future studies are needed to further elucidate the underlying pathophysiology of this complex disorder as well as to gain a better understanding of the optimal treatment strategies and long-term outcomes of this unique patient population.