Vascular ultrasound in patients with mechanical circulatory support devices: from pre-implant assessment to post-decannulation surveillance

Mechanical circulatory support (MCS) devices, including extracorporeal membrane oxygenation (ECMO), left ventricular assist devices (LVADs), and intra-aortic balloon pumps (IABP), are increasingly used in patients with severe cardiac or cardiorespiratory failure. Despite major technical advances, vascular complications related to cannulation, device support, and decannulation remain frequent. Duplex ultrasound (DUS) is the primary vascular imaging modality because it is fast, can be performed at the patient’s bedside, is repeatable, and provides functional data via Doppler imaging. However, this is a specialized examination requiring expertise, as the flows are significantly altered by MCS, and the ultrasound findings are specific. This review summarizes current applications of DUS in patients supported with extracardiac MCS devices, organized into three key phases: pre-implant assessment, monitoring during mechanical support, and post-decannulation surveillance. Pre-implant DUS allows detailed evaluation of arterial and venous anatomy, vessel diameter, patency, and wall morphology, guiding cannulation strategy and cannula selection while facilitating ultrasound-guided percutaneous access. During MCS support, DUS plays a critical role in assessing limb perfusion, cannula positioning, and diagnosing vascular complications, particularly in patients unable to report ischemic symptoms. After decannulation, systematic ultrasound surveillance enables early detection of access-related complications, including thrombosis, pseudoaneurysm, arteriovenous fistula, arterial dissection, and acute limb ischemia. The objective is to guide the ultrasound practitioner in performing and interpreting DUS at each stage of the assessment of critically ill patients with an MCS device.