Isolated atresia of the left main coronary artery in an adult

A case series of left main coronary artery ostial atresia and a review of the literature

Left main coronary artery ostial atresia (LMCAOA) is a rare congenital anomaly of the coronary arteries. The published literature regarding the current diagnostic and management recommendations are limited. We present three case series of LMCAOA from our institution, including one with a unique association with anomalous origin of left coronary artery (LCA) from pulmonary artery. In addition, this report includes a review of 50 pediatric and 43 adult cases from literature. The majority of the patients were symptomatic. Sudden cardiac death occurred in 10% of pediatric patients and 7% of adult patients. Almost half of pediatric patients had additional cardiac lesions. At the time of diagnosis, 82% of patients had abnormal exercise stress test and 73% had abnormal myocardial perfusion imaging (MPI). The diagnosis of LMCAOA was suspected by echocardiography in 47% of pediatric patients, while 26% were initially misdiagnosed as anomalous origin of LCA from pulmonary artery. Coronary angiography confirmed the diagnosis in most cases and 70.5% of pediatric patients had small collaterals, while 80.5% of adult patients had large collaterals. Nine pediatric patients had no revascularization surgery with five deaths. Revascularization surgery was performed in 39 pediatric patients with four deaths. After 2005, there is a gradual shift toward performing coronary osteoplasty rather than coronary artery bypass grafting. Eighteen adult patients had revascularization surgery and all survived. Fifteen adult patients had no revascularization surgery, of which there were five deaths. In patients with LMCAOA, revascularization surgery is currently recommended in the presence of symptoms, ischemic changes on electrocardiogram or exercise stress test, myocardial perfusion defect on MPI, global left ventricular systolic dysfunction on echocardiogram, severe mitral regurgitation, or small-sized collaterals in coronary angiography. Short-term and mid-term outcomes are encouraging.

Severe congenital stenosis of the left coronary artery ostium and its possible pathogenesis according to current knowledge on coronary artery development

We report a 72-year-old woman with severe congenital stenosis of the left coronary artery orifice and clinically significant atherosclerotic changes in both the right and left coronary arteries. The stenotic ostium was located at the point at which the left and posterior aortic valve leaflets joined to form the left commissure, just at the distal vertex of the left interleaflet triangle, between the left and posterior aortic sinuses. The right coronary artery was more developed in size than usual, whereas the left coronary artery consisted of a short left main coronary trunk that bifurcated into left anterior descending and left circumflex arteries. The left coronary artery system was filled retrogradely through two vessels proceeding from the right coronary artery, namely, the conal artery and a well-developed branch that ran across the interventricular septum. This abnormal arrangement of the coronary arteries showed striking functional similarities with atresia of the left main coronary artery. Current knowledge on the morphogenesis of the coronary arteries suggests that the present anomalous coronary artery pattern resulted from the penetration of the anticipated left coronary artery system into the aorta at a totally erroneus site. This hindered the normal development of the ostium, which subsisted as a punctiform, practically nonfunctional opening.

Two adult cases of congenital atresia of the left coronary ostium—comparison of a sudden death case with a long-term survival case

We present two extremely rare autopsy cases with atresia of the left coronary ostium. Case 1 was a 34-year-old man who died of sudden cardiac causes with localized acute subendocardial infarction and Case 2 was an 82-year-old woman who died from non-cardiac causes. In both cases, a string-like small left main trunk that was located in its normal position was found; however, the orifice of the left coronary artery was absent in both cases. The collateral artery (CA), whose caliber was smaller than that of the proximal left descending artery (LAD), arose from the right coronary sinus and was anastomosed with the distal LAD. However, it was only in Case 1 that the CA showed an acute angle of take-off from the aorta, subsequently coursing between the root of the aorta and the pulmonary trunk, with possible mechanical compression by these two arteries. These two cases suggest that atresia of the left coronary ostium is developmentally and anatomically different from single coronary artery or left coronary artery arising from the opposite sinus of valsalva. Atresia of the left coronary ostium is considered to be an important differential diagnosis as a cause of sudden death, not only in the pediatric population but also in adults. The caliber and/or other anatomical features of the CA may predominantly dictate the clinical course of patients with atresia of the left coronary ostium.

Left main coronary artery atresia: literature review and therapeutical considerations

OBJECTIVE

Left main coronary artery atresia is a rare coronary anomaly in which there is no left coronary ostium, the proximal left main trunk ends blindly, blood flows from the right coronary artery to the left via small collateral arteries and retrogradely in at least one of the left-sided arteries. Since published case reports are few and rather scattered, no comprehensive information about this uncommon anomaly is available.

METHODS

A through search for published cases of left main coronary atresia was performed in the major medical journals by electronic (MEDLINE and INTERNET) and hand-scanning.

RESULTS

The authors found 28 cases of left main atresia (including two from their own experience), 15 of which were pediatric; five of these cases had associated cardiac anomalies. While pediatric patients were usually overtly symptomatic early in their life (syncope, dyspnea, sudden death, failure to thrive, infarction, ventricular tachycardia), adult patients began showing symptoms (angina, dyspnea, sudden death) only at an advanced age; associated coronary atherosclerosis seemed to be uncommon, though (2/13 adult patients, 15%). We know of only one asymptomatic patient, a 76-year old lady who had died of unrelated causes; in her case left main atresia was an unforeseen autopsy finding. Four untreated patients had died suddenly; most of the others were highly symptomatic and required surgical therapy, usually as direct coronary artery revascularization via one or more saphenous vein or mammary artery grafts to the left-sided arteries; all revascularized patients were reported to be alive and well; in one pediatric case the left main coronary artery was reconstructed using an aortic wall baffle, with a good result. In contrast, the outcome of patients who did not receive revascularization has been poor.

CONCLUSION

In light of the favorable results obtained by surgical therapy, the authors endorse prompt coronary artery revascularization for all patients with left main coronary artery atresia.