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Conventional approach, permitting rescue transseptal left atrial cannulation if clinical signs of increased left ventricular afterload appeared
Early routine left ventricular unloading by intracardiac-echo-guided transseptal left atrial cannulation, Y-connected into the ECMO drainage limb, within 12 hours of randomisation (achieved at a median of 1.1 hours)
Single-centre, open-label, 116 patients - powered only for a large effect. 50% crossover in the control arm dilutes any true difference. Transseptal left atrial cannulation reduces preload but not afterload, so a null result may reflect the modality rather than the concept. Read via the published abstract and a peer-reviewed review; full text of the Circulation paper not retrieved (inaccessible from this environment). Volume, issue and page numbers unverified. ClinicalTrials.gov NCT04775472.
Adults with cardiogenic shock undergoing VA ECMO, single centre (Chonnam National University Hospital, Gwangju, South Korea), March 2021 to September 2022. Mean age 67.6 plus or minus 13.5 years; 34 (29.3%) women. 58 early versus 58 conventional; all 116 completed the trial.
All-cause mortality within 30 days
30-day death 27 (46.6%) early versus 26 (44.8%) conventional; hazard ratio 1.02 (95% CI 0.59 to 1.74), P=0.942. At 1 year (Eur Heart J Acute Cardiovasc Care 2025;14(4):203-211, DOI 10.1093/ehjacc/zuae150): 33/58 (56.9%) versus 32/56 (57.1%), HR 0.97 (0.60 to 1.58), P=0.887, with no difference in cardiac or non-cardiac mortality, heart-failure rehospitalisation (HR 1.17, 0.43 to 3.24) or the composite. CROSSOVER: 29 of 58 (50%) conventional patients received rescue transseptal cannulation on a clear indication, at a median of 21.8 hours (IQR 12.4 to 52.2). Only significant secondary difference: faster resolution of pulmonary congestion in the early group, median 3 days (IQR 2 to 6) versus 5 (3 to 7), P=0.027.
It does not test unloading against no unloading - half the control arm was unloaded. It does not test the intra-aortic balloon pump or a micro-axial pump, which are the devices the observational mortality signal actually belongs to. It cannot address whether a preload-only strategy that leaves the aortic valve shut is the right physiological target. Single centre, single operator group, single modality.
Routine early left atrial venting in unselected VA ECMO patients does not reduce mortality at 30 days or at 1 year. It does clear the lungs about two days faster. The trial is best read as a TIMING and SELECTION trial: unloading everybody early was compared with unloading the half who developed a clear indication, and the two were equivalent.