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Survival on a left ventricular assist device (LVAD) is better when patients also have an implantable cardioverter defibrillator (ICD), according to a meta-analysis.

Among LVAD patients, all-cause mortality rates were over a mean of 7 months (relative risk [RR] 0.61, 95% CI 0.46-0.82), , of the VA Medical Center in Minneapolis, and colleagues reported online in JACC: Heart Failure.

Those with the newer continuous-flow type of LVAD showed a similar but nonsignificant trend for better survival with an ICD (14% versus 25%, RR 0.76, 95% CI 0.51-1.12).

"ICD use was associated with a significant reduction in mortality in LVAD patients, however, this effect was not significant in patients with continuous-flow LVADs," the authors observed. Still, "we believe that ICDs should continue to be used in patients with continuous-flow LVADs until further randomized clinical trial data become available."

"The evidence supporting ICD use in patients with LVADs is limited to a few, relatively small studies. Current practice guidelines supporting ICD use in LVAD patients are therefore predominantly based on expert consensus and observational studies. To the best of our knowledge, this is the first comprehensive systematic review in an area that currently lacks prospective cohort studies or randomized trials."

"While these data support the use of ICDs, larger-scale randomized trial data are strongly warranted to evaluate ICD effectiveness in patients with current generation LVADs," Vakil and colleagues concluded.

There were six observational studies in the meta-analysis of LVAD recipients (n=937). Patients were 53 years old on average, and 80% were men. Bridge-to-transplantation was the indication for LVAD use in 93% of patients; a continuous-flow LVAD was used in 39% of cases.

Of the study population, 38% of patients also had an ICD.

That minority of patients had fewer blood stream or device-related infections over follow-up (6% versus 18% for no-ICD group, P<0.01). This finding was hard to explain -- given the lack of patient-level data -- but may "reflect a selection bias of not implanting ICDs in patients at relatively higher risk for infections," the investigators suggested.

Patient characteristics were also limitations of the study.

"This cohort was enriched with patients (93%) that received an LVAD as bridge-to-transplantation," the researchers pointed out. "As such, these results cannot be generalized to patients receiving destination therapy LVADs who are known to be relatively sicker than those awaiting transplantation."

Vakil's group also commented that they were missing key information, such as the burden of ventricular arrhythmias and its relation to the timing of LVAD implantation, ICD therapy, and ICD programming. Importantly, they couldn't know for sure if patients died of sudden or nonsudden deaths. The authors acknowledged that they also failed to totally exclude patients with biventricular assist devices (17%) and right ventricular assist devices (4%).

Taken in sum, the caveats to the meta-analysis left many questions standing.

"Although ventricular arrhythmias are common and frequently associated with increased mortality in patients with LVADs, it is suggested that sudden cardiac death is an uncommon mode of death in these patients. In previous studies, patients with LVADs have been reported to survive for days to months despite being in rapid ventricular arrhythmias. As such it is postulated that mortality in these patients is primarily related to right heart failure and renal dysfunction," the investigators wrote. "Hence, the benefit of ICDs in patients with LVADs has remained unclear."

Nonetheless, they maintained that their results "support and strengthen the current guideline recommendations regarding the use of ICDs in LVAD patients."

"Randomized trial data are strongly warranted that can address the utility, optimal device programming, and timing of ICD implantation in the current generation continuous-flow LVAD patients with and without ventricular arrhythmias."

Ideally, those trials would address both bridge-to-transplant and destination therapy use, the researchers added.

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