A randomized trial presented at the American College of Cardiology's Annual Scientific Session (ACC.26) on Mar. 29 found that using a temporary, miniaturized heart pump during percutaneous coronary intervention (PCI), also known as coronary angioplasty, did not improve outcomes for patients with severe coronary artery disease and moderate to severe heart failure compared to standard PCI alone. The study reported that after two years, patients who received the pump had nearly double the risk of dying from cardiovascular events compared to those who received standard care.
The findings are significant because left-ventricular unloading with a mechanical pump has become more common in recent years among cardiologists performing PCI on high-risk patients. The expectation was that this device would protect both the patient and their heart during procedures; however, evidence supporting its routine use has been lacking.
"We found no evidence that use of the temporary pump protected the heart during the angioplasty procedure," said Divaka Perera, MD, professor of cardiology at King's College London and first author of the study. "Our findings strongly suggest that we shouldn't be using this device routinely without more evidence of benefit." Perera explained that while left-ventricular unloading is intended to reduce stress on the heart by temporarily taking over some pumping function, it can cause complications such as bleeding or injury to blood vessels.
The BCIS-3 trial enrolled 300 patients at 21 sites in the UK. Participants were randomly assigned either PCI with LV unloading or standard PCI alone. Most participants were men with an average age of 73; all had extensive coronary disease and severely impaired left ventricular function—pumping out only about 27% of blood per contraction versus a healthy range of 50%–70%. Seventy-five percent had acute coronary syndrome indicating high risk for further cardiac events.
Analysis showed no statistically significant difference between groups regarding death from any cause, disabling stroke, myocardial infarction, hospitalization for cardiovascular causes or peri-procedural injury—the primary composite endpoint. However, secondary analysis revealed a higher overall death rate among those receiving LV unloading: about a 50% increased risk compared to standard care (32.6% vs. 23.4%), including an absolute increase in deaths from cardiac causes (26.7% vs. 14.5%).
Perera said these results were unexpected: "This was surprising because the whole premise of LV unloading was that it protects the heart," he said. "But we found that patients assigned to LV unloading had more damage to the left ventricle than those assigned to standard care." Rates of bleeding and vascular injuries were low in both groups; other outcomes such as strokes and hospitalizations did not differ significantly between groups.
Study limitations include its predominantly male population based entirely in one country and exclusion of patients experiencing cardiogenic shock—a life-threatening emergency where blood pressure drops dangerously low due to poor cardiac output—which may affect generalizability elsewhere or among women.
Further research is planned into understanding why mortality rates increased with LV unloading devices as well as cost-benefit analyses comparing both approaches.
