Left Main Coronary Artery Compression Syndrome
Evaluation With 64-Slice Cardiac Multidetector Computed Tomography
A 28-year-old man presented to the emergency department with progressive shortness of breath complicated by large hemoptysis. At 3 months of age, he had been diagnosed with a “hole in his heart” in the Ukraine and had undergone 3 coronary catheterizations (2 in Russia, 1 in India; results unavailable). His parents had declined options for treatment. After stabilization in the emergency department, he was transferred to coronary care, where echocardiography demonstrated a persistent ductus arteriosus (PDA) measuring 0.9×2.0 cm with a right-to-left shunt consistent with Eisenmenger syndrome. Left ventricular function was severely impaired (ejection fraction=21%).
Cardiac 64-slice multidetector computed tomography (MDCT) was undertaken to provide optimal depiction of the PDA and main pulmonary artery (PA) and confirmed a widely patent PDA measuring 2.0 cm in largest diameter (Figure 1A). Functional MDCT cine multiphase reconstructions of the PDA revealed a bidirectional shunt (Movie I). Main, left, and right PAs were markedly enlarged (Figure 1B). Coronary MDCT evaluation demonstrated severe left main coronary artery (LM) compression >90% between the aortic sinus and the enlarged PA (Figure 1C). Additionally, coronary MDCT demonstrated a downward angulation of the LM with the left sinus of Valsalva of 11° (Figure 1D). Functional MDCT cine multiphase reconstructions demonstrated dynamic compression of the LM between the aortic sinus and the PA during systole (Movie II and III) and confirmed severe global left and right ventricular dysfunction (Movie IV). Noncardiac findings included pulmonary hemorrhage and pulmonary parenchymal peripheral vascular pruning that were consistent with severe pulmonary hypertension and Eisenmenger syndrome (Figure 1E).
Coronary angiography confirmed LM stenosis (Figure 2; Movie V), and hemodynamic evaluation revealed a Qp/Qs of 1.05. Three days after catheterization, the patient suffered a cardiac arrest and underwent percutaneous transcatheter intervention with stent placement across the LM. The patient declined heart–lung transplantation and was discharged in stable condition. The patient remains event free at 4-month follow-up.
Left coronary artery compression syndrome was first described in 1957 and is characterized by compression of the LM between the aorta and an enlarged main PA.1 It is usually seen with a congenital cardiac defect, most commonly an atrial septal defect, ventricular septal defect, or tetralogy of Fallot.2 The association between an isolated PDA and left coronary artery compression is rare.3 Both the degree of LM compression and its angle with the left sinus of Valsalva <30° are thought to increase the likelihood of significant myocardial ischemia. A main PA/aorta diameter ratio >2 is considered an additional risk factor. Cardiac 64-slice MDCT provides a noninvasive method for evaluating the degree of dynamic LM compression throughout the cardiac cycle, angulation of the LM relative to the left sinus of Valsalva, evaluation of left and right ventricular function, and depiction of pulmonary pathology, making it a valuable investigation in the workup of patients suspected of left coronary artery compression.
The online-only Data Supplement, consisting of movies, is available with this article at http://circ.ahajournals.org/cgi/content/full/115/1/e7/DC1.
Corday E, Gold H, Kaplan L. Coronary artery compression; an explanation for the cause of coronary insufficiency in pulmonary hypertension. Trans Am Coll Cardiol. 1957; 7: 93–103.
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