A previously healthy, middle-aged patient presented with rapidly increasing shortness of breath despite empirical antibiotic treatment for presumed pneumonia. A computed tomographic image of the chest was notable for diffuse, ground-glass opacities. An infectious disease workup was unrevealing, and the patient was diagnosed with acute-on-chronic respiratory failure resulting from dermatomyositis-associated interstitial lung disease. Progressive hypoxia refractory to mechanical ventilation necessitated venovenous extracorporeal membrane oxygenation (VV ECMO) using the ProtekDuo dual-lumen cannula (LivaNova). In its standard configuration, deoxygenated blood is drained from the right atrium while oxygenated blood is ejected into the main pulmonary artery, and the device serves as both a right ventricular support and an ECMO (RVS-ECMO) cannula. End-stage lung disease was established and, as part of a lung transplant evaluation, the patient underwent catheterization of the left side of the heart and coronary angiography. The left coronary artery angiogram revealed mild luminal irregularities. The right coronary artery (RCA) angiogram shows compression of the right coronary artery during systole and diastole.
This report illustrates how the hinge point of the RVS-ECMO cannula in the right ventricle of the RCA may cause extrinsic compression to the RCA. A U-shaped configuration of the cannula, with a less acute angle, is less likely to cause this than a more acute V-shape configuration. If a V shape is recognized after advancing the distal tip of the cannula to the desired position, we advise retracting the cannula under fluoroscopic guidance, which attenuates the angle at the hinge point of the cannula.
The RVS-ECMO cannula was repositioned at the time of catheterization. The patient remained hemodynamically stable without cardiac complaints. He subsequently underwent a successful lung transplant.
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