Pulmonary Artery Reduction Plasty for LMCA Compression Syndrome in a Case of Adult Congenital Heart Disease

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Extrinsic left main coronary artery (LMCA) compression can be caused by pulmonary artery (PA) enlargement in the setting of pulmonary artery hypertension (PAH). Due to the proximity to the LMCA, a dilated PA trunk or aneurysm can compress the LMCA, resulting in narrowing of the LMCA and angina pectoris, a condition referred to as LMCA syndrome (1). Although left main compression can lead to ischemic chest pain, myocardial infarction (2), and sudden death (3), it often remains underdiagnosed, with its symptoms frequently attributed to PAH. Given the increased surgical risk in patients with Eisenmengerization, LMCA stenting is usually the first therapeutic option. However, surgery remains a viable option in cases requiring concurrent surgical correction of the congenital heart disease. 

A 34-year-old male was referred to the authors with chief complaints of retro-sternal angina that had persisted for one month. The angina was sudden in onset, dull aching in type, non-radiating, and relieved by rest, and it was associated with palpitations. A clinical examination revealed a pansystolic murmur with fixed splitting of the second heart sound. Echocardiography suggested a partial atrioventricular canal defect (AVCD) with moderate left atrioventricular valve regurgitation (AVVR) and moderate PAH. The chest X-ray showed an enlarged right atrium with an enlarged pulmonary artery silhouette and pulmonary plethora. The 12-lead electrocardiography showed ST depression and T-wave inversion in the lateral leads. CT angiography showed moderate to severe compression of the ostium of the LMCA by the dilated pulmonary artery. The dimensions were: main pulmonary artery (MPA) measured 46 mm, right pulmonary artery (RPA) measured 36.5 x 33.6 mm, and left pulmonary artery (LPA)- measured 31.4 x 27.7 mm. 

The ostium primum atrial septal defect was closed with an autologous untreated pericardial patch, and the cleft in the superior bridging leaflet was also closed. The MPA was dilated with the RPA and LPA. Pulmonary artery reduction plasty was performed using Hegar’s dilator size 20 for the MPA and size 14 for the branch pulmonary arteries. 

Postoperative transesophageal echocardiography showed mild left atrioventricular valve regurgitation (AVVR), no flow across the interatrial septum (IAS), and normal biventricular function. A postoperative CT coronary angiography indicated that the compression of the LMCA was relieved. The patient’s postoperative period was uneventful, and he was discharged on postoperative day eight. 

Given the prevalence of LMCA compression, its associated risks, and the wide array of effective treatment options, maintaining a high degree of suspicion for this condition and intervening in a timely fashion remains critical. In patients with Eisenmenger syndrome, the treatment of PAH itself and coronary revascularization are the optimal choices. An isolated lesion involving the ostium or shaft of the LMCA is a class II recommendation for percutaneous coronary intervention (PCI). If congenital heart disease can be corrected surgically, aneurysmorraphy, as done in this case, is a feasible option without intervening on the coronary itself.  

The technique used was anteromedial reduction plasty, which relieved compression on the LMCA more effectively compared to anterior reduction plasty. Due to the paucity of such cases reported, the authors reported their experience with anteromedial reduction plasty. 

References

1. Choi yj, kim u, lee js, et al. A case of extrinsic compression of the left main coronary artery secondary to pulmonary artery dilatation. J korean med sci 2013;28:1543-8.
2. Sharma, h., doshi, s. N., nadir, m. A. (2021). Acute myocardial infarction due to external compression of the left main coronary artery by a large pulmonary artery aneurysm. Case reports in cardiology, 2021, 8850044. Doi 10.1155/2021/8850044.
3. Demerouti, e. A., manginas, a. N., athanassopoulos, g. D., karatasakis, g. T. (2013). Complications leading to sudden cardiac death in pulmonary arterial hypertension. Respiratory care, 58(7), 1246–1254. Doi 10.4187/ respcare.02252.
4. Eisenmenger syndrome with left main compression syndrome: a case report by Charlotte Johanna Cool,Fathy Fathini, Ibnu Adams, Aninka Saboe, Nuraini Yasmin Kusumawardhani, Astri Astuti, and Achmad Fauzi Yahya

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