A groundbreaking randomized clinical trial has revealed that utilizing a temporary heart pump to support the left ventricle during angioplasty offers no discernible improvement in patient outcomes for individuals with severe coronary heart disease and moderate to severe heart failure. Furthermore, the study unveiled a concerning trend: patients who received this mechanical support faced nearly double the risk of cardiovascular death within two years compared to those undergoing standard care. These significant findings were presented at the American College of Cardiology’s Annual Scientific Session (ACC.26), prompting a reevaluation of this increasingly common medical practice.
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Reassessing a Standard Practice in Cardiology
The practice of left-ventricular (LV) unloading involves inserting a tiny mechanical pump into the heart via the femoral artery to temporarily reduce the workload of the heart’s main pumping chamber. This technique has been increasingly adopted by cardiologists over the last decade during percutaneous coronary intervention (PCI), commonly known as coronary angioplasty. PCI is a minimally invasive procedure designed to restore blood flow to the heart by inserting a balloon and stent into blocked coronary arteries.
Despite its growing use, the widespread adoption of LV unloading during PCI was largely driven by an assumption of benefit rather than robust evidence from randomized trials. Dr. Divaka Perera, a professor of cardiology at King’s College London and the study’s lead author, highlighted this disparity. “We found no evidence that use of the temporary pump protected the heart during the angioplasty procedure. Our findings strongly suggest that we shouldn’t be using this device routinely without more evidence of benefit,” Dr. Perera stated.
While the goal of LV unloading is to protect the heart, experts acknowledge potential adverse effects, including the risk of blood vessel injury such as bleeding, tearing, or blockages.
Detailed Trial Findings and Unexpected Risks
The BCIS-3 trial was the first randomized study to directly compare standard PCI with PCI augmented by LV unloading. It aimed to determine if the pump could reduce life-threatening complications and improve outcomes for patients suffering from extensive coronary artery disease and severe impairment of the left ventricle. The trial enrolled 300 patients across 21 sites in the UK, with an average age of 73; participants were predominantly male (83%) and White (85%).
A significant portion of the patients (75%) had acute coronary syndrome, indicating a high risk of heart attack. All participants also presented with extensive coronary disease, defined as at least 70% blockage in two or more coronary arteries, or at least 50% blockage in the main coronary artery. Critically, their left ventricles were severely impaired, pumping out an average of only 27% of blood with each contraction, far below the healthy range of 50% to 70%.
The study’s primary endpoint, a composite measure including death from any cause, disabling stroke, heart attack, cardiovascular hospitalization, and heart injury during treatment, showed no statistically significant difference between the two groups. When comparing patient pairs, standard care was better in 43% of cases, while LV unloading was better in 36.6%.
However, secondary outcomes revealed a concerning trend. Patients receiving LV unloading experienced an approximate 50% elevated risk of death from any cause (32.6% vs. 23.4% for standard care) and a 12.2 percentage point absolute increase in the risk of dying from a heart-related condition (26.7% vs. 14.5% for standard care). Dr. Perera expressed surprise at these results, noting, “This was surprising because the whole premise of LV unloading was that it protects the heart. But we found that patients assigned to LV unloading had more damage to the left ventricle than those assigned to standard care.” While rates of bleeding and blood vessel injuries were low in both groups, ruling them out as the primary cause for the elevated death rate in the LV unloading arm, the signal of harm was undeniable.
Implications, Limitations, and the Path Forward
Despite the higher mortality rate being a secondary outcome, researchers consider it a strong indication of potential harm associated with LV unloading. This finding challenges the conventional wisdom surrounding the device’s protective role during high-risk angioplasty procedures.
The study had certain limitations, including a participant demographic that was predominantly male and exclusively from the UK, which may limit the generalizability of the findings to women or other healthcare systems globally. Additionally, patients experiencing cardiogenic shock, a severe life-threatening emergency, were not included in the trial. Future research is crucial to delve deeper into the specific causes behind the increased rates of death and heart injury observed in the LV unloading group. Dr. Perera and his team are also conducting a cost-benefit analysis, expected to be presented later this year, to further inform clinical guidelines.
The study, funded by the UK’s National Institute for Health & Care Research, was simultaneously published online in the New England Journal of Medicine.
