New Safety Questions Over Mechanical Circulatory Support

For circulatory support in cardiogenic shock, the best choice between Impella and intra-aortic balloon pump (IABP) has been controversial. Now, new data is complicating the debate.

Presenting at the Society for Cardiovascular Angiography and Interventions in Washington, DC, Godbless Ajenaghughrure, MD, an internist and resident at Trihealth Good Samaritan Hospital in Cincinnati, Ohio, reported that Impella use is associated with higher 30-day mortality compared to IABP.

The new propensity-matched analysis shows that Impella use at 1 month is linked to significantly higher all-cause mortality (42.3%) compared with IABP (29.6%; hazard ratio [HR], 1.594; 95% CI, 1.396-1.820; P < .001). 

Cardiac Arrest and Sepsis

Patients treated with Impella also had higher rates of cardiac arrest (33.9% vs 26.8%; HR, 1.310; 95% CI, 1.135-1.511; P < .001) and sepsis (14.6% vs 12.3%; HR, 1.410; 95% CI, 1.070-1.858; P = .024). 

There were no significant differences in rates of acute kidney injury (14.6% vs 12.3%; P = .090), cerebral infarction (10.1% vs 8.4%; P = .130), atrial fibrillation (27.7% vs 27.1%; P = .754), ventricular tachycardia (21.8% vs 23.7%; P = .254), or gastrointestinal bleeding (12.8% vs 12.4%; P = .689).

Researchers used the large healthcare database TriNetX to conduct the analysis comparing 30-day outcomes between patients who received either Impella (n = 1256) or IABP (n = 1256) support for cardiogenic shock.

Patients were well-matched for heart failure, atrial fibrillation, diabetes, chronic kidney disease, and prior myocardial infarction, the authors report.

Cardiogenic shock affects between 40,000 and 50,000 people in the US a year and is the leading cause of in-hospital mortality after acute myocardial infarction. One-year mortality rates are as high as 50%. 

In interventional cardiology, specialists use several types of mechanical circulatory support devices for patients in cardiogenic shock, especially after an acute coronary syndrome or myocardial infarction. Impella and IABP are two devices inserted percutaneously, typically through the femoral artery, and occasionally through the axillary artery.

More Support, Not Necessarily Better

Impella, a temporary rotary heart pump, provides stronger circulatory support than the traditional balloon pump, explained Diljon Chahal, MD, a cardiologist at University of Maryland Medical Center in Baltimore. However, he said, the Impella catheter is significantly larger than the IABP catheter, which can increase the risk of bleeding, vascular injury, and infection. 

“There has been ongoing controversy over which device may be better for patients in cardiogenic shock. Several prior studies, including the IMPRESS and ISAR-SHOCK trials, showed no significant difference in 30-day mortality between Impella and IABP in this setting,” he pointed out.

“While Impella does provide greater immediate hemodynamic support, this new propensity-matched analysis shows that greater support does not necessarily translate into better outcomes,” he said. “The findings of higher 30-day mortality, more cardiac arrests, and higher rates of sepsis suggest that device-related complications may offset the intended benefits, particularly when used broadly without careful patient selection.”

This current analysis “is thought-provoking and reinforces the need for more randomized trials with longer-term follow-up,” he said. “Until we have stronger prospective data, mechanical support decisions must be individualized, carefully balancing risks and benefits, rather than assuming that more support is always better. Although this study is valuable, the jury is still out on whether Impella offers a true survival advantage over IABP in cardiogenic shock.”

Drs Ajenaghughrure and Chahal report no relevant financial disclosures.