Coronary hypoplasia or hypoplastic coronary artery disease (HCAD) is a congenital coronary artery anomaly of intrinsic anatomy and can be defined as one or more coronary arteries being abnormally small or underdeveloped.
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Epidemiology
Hypoplastic coronary artery disease is described as a rare condition and has been reported in about 2.2% of patients with coronary anomalies 1.
Associations
Clinical conditions associated with coronary hypoplasia include 1-4:
- superdominant coronary artery
- other congenital coronary artery anomalies
- sudden cardiac death
Clinical presentation
Clinical symptoms of coronary hypoplasia depend on the extent of the condition and the collateralisation from the other coronary arteries. The condition can be entirely asymptomatic or can present with cardiovascular symptoms like dyspnea, chest pain, dizziness or syncope.
Complications
As with other congenital coronary anomalies the most dangerous and rightly feared complication of coronary hypoplasia is sudden cardiac death.
Other complications include 1-4:
Pathology
An ample description of coronary hypoplasia is a narrow lumen and/or a short course. Generally, a luminal diameter of <1.5 mm has been suggested but this might vary with respect to coronary arterial dominance and affected artery or arterial segment. One or more coronary arteries can be hypoplastic 1-3.
Radiographic features
Coronary angiography
Invasive coronary angiography (ICA) can demonstrate one or more coronary arteries with a narrow lumen <1.5 mm and/or a short course 1,2.
CT
Coronary CTA can visualize the hypoplastic coronary arteries and any associated congenital coronary anomalies as well as depict or characterize eccentric coronary plaques. In addition, it can demonstrate myocardial hypoperfusion, thinning or calcification suggesting myocardial ischemia, myocardial infarction or myocardial scar formation 4.
MRI
Coronary MRA can be alternatively used for the evaluation of the coronary anatomy and due to the fact that it is neither invasive nor associated with any radiation exposure, it might be considered for younger patients.
In addition, it might be combined with stress-perfusion and/or myocardial viability protocol to demonstrate complications as myocardial ischemia or scar formation 4.
Nuclear medicine
Nuclear stress-testing might be performed for the assessment of myocardial ischemia 4.
Radiology report
The radiological report should include a description of the following features:
- hypoplastic coronary artery segment with location based on the AHA coronary artery segment model
- left main coronary artery and variant anatomy
- circumflex artery with course, branches and segments
- left anterior descending artery with course branches and segments
- right coronary artery origin, course, segments
- coronary artery disease and stenoses with location based on the AHA coronary artery segment model
- other congenital coronary artery anomalies
- any signs of complications
Treatment and prognosis
Due to an increased risk of ventricular arrhythmia, the implantation of an implantable cardioverter-defibrillator (ICD) has been recommended 1,2.
History and etymology
Hypoplastic coronary artery disease (HCAD) has been first reported by JA Ogden in 1970 6.
Differential diagnosis
Clinical conditions that can mimic coronary hypoplasia:
- coronary vasospasm
- coronary artery disease: usually associated with coronary plaques (calcified, non-calcified, mixed)
- absence of a coronary artery