Impact of Left Ventricular Unloading on Hemodynamics and Stunning in Complex PCI: A CHIP-BCIS3 Substudy

Elective left ventricular (LV) unloading during high-risk percutaneous coronary intervention (PCI) is hypothesized to mitigate hemodynamic instability and myocardial stunning, but has not been evaluated in a randomized trial.

This prespecified substudy of the CHIP-BCIS3 (Controlled Trial of High-risk Coronary Intervention With Percutaneous Left Ventricular Unloading) trial evaluated whether elective LV unloading with a microaxial flow pump (mAFP) reduces hemodynamic instability and postprocedural stunning.

Patients with severe LV systolic dysfunction undergoing complex PCI were randomized to elective LV unloading with an mAFP or standard care. Invasive hemodynamics were assessed using pulmonary artery catheterization at baseline and post-PCI. The coprimary outcomes were systolic blood pressure reduction, loss of pulse pressure (LOPP), and requirement for inotropes. Secondary outcomes included changes in cardiac index, LV filling pressure, and frequency of peri-procedural myocardial injury.

Of 125 eligible patients, 97 were enrolled (50 mAFP; 47 standard care). Baseline cardiac index was 2.10 ± 0.55 L/min/m². The incidence of systolic blood pressure reduction was similar between groups (relative risk [RR]: 0.86; 95% CI: 0.58-1.29), whereas inotrope use was lower with mAFP (RR: 0.57; 95% CI: 0.34-0.97). LOPP was more frequent with mAFP (RR: 7.83; 95% CI: 2.53-24.24) and was associated with peri-procedural myocardial injury (OR: 3.00; 95% CI: 1.00-9.03). Changes in cardiac index (-0.25 vs -0.24 L/min/m²; P = 0.20) and pulmonary capillary wedge pressure (2 vs 3 mm Hg; P = 0.79) were similar between groups.

In patients undergoing complex PCI, elective LV unloading with mAFP reduced inotrope requirements but increased LOPP and did not prevent myocardial stunning. (Controlled Trial of High-risk Coronary Intervention With Percutaneous Left Ventricular Unloading [CHIP-BCIS3]; NCT05003817).