• „ CLINICAL VIGNETTE

Acute coronary syndrome due to extrinsic left main compression

Dominik Maj1, Tomasz Kopiec1, Małgorzata Wieteska2, Aleksandra Gąsecka1, Bartosz Rymuza1, Arkadiusz Pietrasik1

11st Chair and Department of Cardiology, Medical University of Warsaw, Warszawa, Poland

2Chair and Department of Epidemiology and Clinical Research Methodology, Medical University of Lublin, Lublin, Poland

Left main (LM) compression syndrome is defined as the LM stenosis due to extrinsic compression, triggering symptoms of myocardial ischemia. The prevalence is 5%–44% in patients with pulmonary arterial hypertension (PAH) [1]. The diagnostics and treatment algorithms in LM compression syndrome are not clearly defined.

We report here a 49-year-old male with atrial septal defect (ASD) type 2 and PAH, who was admitted to the emergency department because of typical symptoms of the acute coronary syndrome (ACS). The electrocardiogram revealed features of myocardial ischemia. Echocardiography showed a reduced ejection fraction (30%), enlarged right ventricle (52 mm) and left atrium (46 mm), elevated systolic pulmonary pressure (80 mm Hg), and bidirectional flow in ASD type 2 (Figure 1A).

Coronary angiography raised suspicion of significant stenosis in the proximal segment of LM (Figure 1B). Intravascular ultrasound (IVUS) demonstrated the elliptical shape of LM without atherosclerotic lesions (Figure 1C, Supplementary material, Video S1). Computed tomography revealed significant dilation of the pulmonary trunk compressing the LM, hence confirming the diagnosis (Figure 1D–E). Due to the symptoms of overt heart failure, a decision to pursue invasive treatment was made. An intra-aortic balloon pump was implanted and IVUS-guided LM percutaneous coronary intervention was performed (bare-metal stent 4.5/15 mm; Figure 1F). Post-intervention IVUS showed good stent expansion and no features of LM compression. Further clinical course was uneventful. During a follow-up hospitalization, right heart catheterization confirmed the Eisenmenger syndrome. The 5-year follow-up was uneventful regarding recurrent ACS.

Considering the non-specific symptoms of LM compression, the diagnosis is challenging. The most effective non-invasive imaging methods are cardiac computer tomography and cardiac magnetic resonance imaging [2]. If the imaging suggests abnormalities, it is necessary to perform coronary angiography followed by intravascular imaging [2]. In our case, since IVUS clearly demonstrated the extrinsic LM compression, and given a strong correlation between IVUS and fraction flow reserve, the latter was not performed. Considering that LM compression syndrome is not common, there is insufficient research to establish the gold standard treatment. Some authors suggest that coronary artery bypass grafting should be performed [3]. However, surgical treatment is associated with the high risk of mortality in severe PAH patients, and our patients had previously rejected the proposed surgical treatment of ASD [4]. There have been several reports of successful percutaneous coronary intervention (PCI) with either bare-metal stents (BMS) or drug-eluting stents in LM compression, showing comparable results regardless of stent type up to 3 years [2, 5]. Considering the large vessel diameter, no evidence of atherosclerotic plaque, the risk of hemoptysis, and potential treatment with prostacyclin agonist or anticoagulants due to Eisenmenger syndrome, BMS was selected, with a good clinical result during 5-year follow-up.

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