ECT/18F-FDG PET-CT for myocardial viability assessment during VA-ECMO support in AMI-related cardiogenic shock: a case series and literature review

Abstract

Weaning patients from veno-arterial extracorporeal membrane oxygenation (VA-ECMO) after acute myocardial infarction-related cardiogenic shock (AMI-CS) depends on whether the injured left ventricle can recover. Cardiac magnetic resonance imaging is often impractical during ECMO support. Nuclear imaging may help, but its role in this unstable setting remains poorly defined. We report six consecutive male patients with AMI-CS and difficulty weaning from VA-ECMO who underwent myocardial perfusion emission computed tomography (ECT) and 18 F-fluorodeoxyglucose positron emission computed tomography ( 18 F-FDG PET-CT) during active support. The case series is used as a clinical entry point for a focused literature review of ECT/SPECT and FDG PET in myocardial viability assessment after myocardial infarction. Imaging was completed in all six patients 12–22 days after ECMO initiation. No transfer- or scan-related adverse event was documented in the available record. Four patients had large estimated left ventricular perfusion defects (54%, 63%, 66%, and 59%) and were managed toward left ventricular assist device support or heart transplantation. One patient with a 41% defect died after withdrawal of life-sustaining therapy because of hepatic failure. One patient with a small estimated defect (4%) was successfully weaned. Prior studies indicate that FDG uptake and perfusion-metabolism mismatch are associated with regional functional recovery after revascularization, but patient-level decisions depend on revascularization, ventricular remodeling, end-organ function, and whether imaging results can be acted on safely. ECT/ 18 F-FDG PET-CT was feasible in this small VA-ECMO case series and provided perfusion and metabolic information when MRI was impractical. The evidence supports its use as an adjunct to clinical, echocardiographic, hemodynamic, and end-organ assessment, not as a stand-alone threshold for weaning, LVAD, or transplantation decisions.