In the United States, a sharp rise in use of percutaneous left ventricular assist devices (LVADs) to provide hemodynamic support in recent years was paralleled by a decline in use of intra-aortic balloon pumps (IABPs), according to an observational study published online March 30, 2015, ahead of print in JAMA Internal Medicine.

“Given the increasing use, costs, and potential complications of [percutaneous LVADs], evidence from well-conducted randomized clinical trials is needed to ensure that [their use] leads to improved patient outcomes,” write Saket Girotra, MD, SM, of the University of Iowa Hospitals and Clinics (Iowa City, IA), and colleagues.

Drawing on National Inpatient Sample data from 2007 through 2012, the investigators found that use of percutaneous LVADs rose 30-fold, with a 25-fold increase in annual implantation volume. In contrast, after a brief rise between 2007 and 2008, use of IABPs declined (table 1).

LVAD use grew in all subgroups, but the greatest increase was seen in patients with cardiogenic shock (P for trend < .001 for all). The decline in IABP use was seen both overall and among patients with cardiogenic shock and acute MI without cardiogenic shock (P for trend < .001). However, IABP use increased slightly in PCI patients without shock or acute MI (P for trend < .001).

Furthermore, between 2007 and 2011, there were increases in the estimated number of hospitals implanting percutaneous LVADs (from 72 to 477), the median hospital volume of procedures with such devices (from 1 to 2.9), and the proportion of LVAD-using hospitals that implanted more than 10 devices per year (from 0 to 21.4%; P for trend < .001 for all).

The mean age of LVAD recipients was 65 years, and the percentage that was older, had comorbidities, underwent PCI, and was covered by Medicare increased over the study period. Diagnoses for implanted patients included:

• Cardiogenic shock: 45.4%
• Acute MI: 52.3%
• Congestive heart failure: 70.1%
• PCI: 66.9%

Overall in-hospital mortality in percutaneous LVAD recipients was 28.8% and in adjusted analysis remained unchanged over time. Mortality was highest in those with cardiogenic shock (47.5%), a finding that persisted after accounting for differences in patient characteristics.

The mean cost of hospitalization for LVAD patients was $85,580. Among LVAD recipients, mean cost was higher for those with cardiogenic shock ($113,695) compared with those with acute MI without shock ($63,485) and PCI with neither shock nor acute MI ($48,900). The mean hospitalization cost for all IABP recipients was considerably lower at $55,168.

Mortality Appears Higher With Percutaneous LVADs

Compared with IABP recipients, LVAD patients were less likely to have cardiogenic shock or acute MI or to undergo CABG but more likely to have congestive heart failure or chronic kidney disease and receive PCI (P < .001 for all). LVAD patients had a shorter hospital stay (10.4 days vs 11.3 days) and were less likely to be discharged to a skilled care facility (16.3% vs 19.7%; both P < .001). However, they tended to have higher unadjusted mortality (21.7% vs 19.5%; P = .05).

In a separate analysis, 1,446 LVAD patients were propensity-matched with 2,888 IABP patients (excluding those who received both devices). Use of percutaneous LVAD vs IABP was associated with higher mortality (OR 1.23; 95% CI 1.06-1.43).

The authors suggest several possible contributors to the shift in practice:

• Percutaneous LVADs have been shown to be more effective in improving hemodynamic parameters in patients with cardiogenic shock.
• Recent randomized trials have questioned the benefit of IABPs in reducing mortality for patients with acute MI in cardiogenic shock undergoing early PCI or elective high-risk PCI.
• Interventionalists have become more comfortable implanting percutaneous LVADs.
• Expedited regulatory approval, aggressive marketing by manufacturers, the growth of physician training programs, and generous physician and hospital reimbursement have encouraged more liberal use of percutaneous LVADs.

Dr. Girotra and colleagues observe that “[w]hereas improvement in hemodynamic parameters with [percutaneous LVAD] implantation has been documented, improvement in survival has not been proven.”

In addition to the continued mortality risk of patients receiving the devices, the authors observe, the “risk of bleeding, vascular injury, and limb ischemia can be substantial… given the use of large-sized cannulae” required for delivery. Moreover, the costs of the devices and postimplantation care are substantial.

“Given the high mortality, uncertain evidence for a clear benefit, risk of complications, and cost, there is a pressing need for carefully designed, adequately powered randomized clinical trials to determine the clinical effectiveness of [percutaneous LVADs] in improving patient outcomes.”

Did the Newer Devices Get a Pass on Approval?

In an accompanying editorial, Joseph S. Ross, MD, MHS, of Yale University School of Medicine (New Haven, CT), observes that “[a]lthough [percutaneous LVADs] are designated as a high-risk device that would traditionally require market clearance through the FDA’s Premarket Approval pathway, requiring clinical evidence of effectiveness and safety, they received market clearance through the FDA’s 510(k) pathway.” The latter demands only demonstration of “substantial equivalence” to a device already on the market—which in this case was likely the IABP, he writes.

“Despite limited clinical evidence to support [LVAD] use, these high-risk medical devices have been rapidly adopted into clinical practice,” Dr. Ross says, adding that unless the FDA requires more, “the best we may be able to offer our patients are substantially equivalent treatments of uncertain benefit.”

In a telephone interview with TCTMD, Jeffrey W. Moses, MD, of Columbia University Medical Center/Weill Cornell Medical Center (New York, NY), said he was not surprised at the uptake of percutaneous LVADs. “This is the advent of a powerful new technology,” he observed. “Use is increasing because it works.”

He noted that the shift from IABPs to the newer devices comes against the backdrop of 2 major trials showing that balloon pumps are not effective in cases of high-risk PCI or cardiogenic shock. “Then along comes this percutaneous technology that gives you much better hemodynamic support, so of course [physicians] are going to turn to that,” Dr. Moses said.

FDA Has Already Raised the Bar

However, Dr. Moses was taken aback by the editorial’s focus on 510(k) approval in light of the fact the FDA has long been in the process of submitting percutaneous LVADs to premarket approval application review and recently approved the Impella 2.5 (Abiomed; Danvers, MA) under this pathway for use in high-risk PCI.

Dr. Moses said the editorial’s implication that marketing of the devices is reckless ignores not only the FDA’s actions but also a great deal of supporting evidence, including the PROTECT II randomized trial, which he characterized as “very positive in terms of reducing hospitalizations and morbidity, if not mortality.” He also referenced data from Abiomed postmarket surveillance registries in the United States and Europe as well as a recent analysis of Medicare patients showing that as LVAD use rose from 2004 to 2011, 30-day and 1-year mortality declined.

“In certain clinical circumstances, you can’t always have upfront randomized data before a device is released,” Dr. Moses asserted. “You have to go with what makes sense.”

Whether use of percutaneous LVADs will continue to grow is difficult to predict, he acknowledged. But Dr. Moses said the new labeling for high-risk PCI may expand its uptake, as will the ongoing DanShock trial if positive. In addition, the changes in practice are consistent with and will likely be bolstered by recommendations in a recently released expert consensus statement from multiple professional societies, he noted.

1. Khera R, Cram P, Lu X, et al. Trends in the use of percutaneous ventricular assist devices: analysis of National Inpatient Sample data, 2007 through 2012. JAMA Intern Med. 2015;Epub ahead of print.

2. Ross JS. High-risk medical devices: why do we not better understand effectiveness and safety [editor’s note]? JAMA Intern Med. 2015;Epub ahead of print.

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