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The majority of patients with an older left ventricular assist device (LVAD) as destination therapy did not exhibit cognitive decline over time, despite a high frequency of strokes, researchers found.

Out of 668 patients who had advanced heart failure and were ineligible for heart transplantation, just under 60% maintained their baseline cognitive performance at 6, 12, and 24 months after HeartWare or HeartMate II placement, reported Sung-Min Cho, DO, MHS, of Johns Hopkins University School of Medicine in Baltimore, and colleagues.

While approximately one in four patients showed cognitive decline at each follow-up, another one in five improved on at least one cognitive measure over baseline (the 83% of patients who went into LVAD placement with some form of cognitive impairment were generally the ones who were able to improve).

Thus, neurocognitive function remained stable or improved within 2 years in roughly 80% of LVAD recipients, Cho and colleagues noted in .

This study was a retrospective analysis of the and trials that randomized LVAD candidates to the HeartWare or HeartMate II systems.

ENDURANCE suggested noninferiority of HeartWare against HeartMate II -- albeit with at 2 years among HeartWare recipients versus 12% in HeartMate II recipients. With ENDURANCE Supplemental, it appeared that could bring down the incidence of strokes.

Nevertheless, neurological problems and mortality forced the HeartWare system off the market entirely in June of this year.

"Given that a reduction in CBF [cerebral blood flow] from decreased cardiac output is the main mechanism of cognitive deficit in patients with heart failure, our study confirms a biological mechanistic plausibility that immediate CBF restoration with LVAD implantation improves cognition for up to 2 years despite frequent occurrence of brain injury during the support," Cho and colleagues wrote.

They reported receipt of the HeartWare device in particular to be a predictor of long-term cognitive decline during LVAD support. Other predictors included male sex, hypertension, and stroke.

Notably, the HeartMate II has been superseded by the HeartMate III, which boasted superior safety in the MOMENTUM 3 trial.

"The field of VADs [ventricular assist devices] is continually showing progress, and older generational pumps are giving way to newer technology that is more forgiving with respect to neurological outcomes and other adverse events," noted Mandeep Mehra, MD, MSc, of Brigham and Women's Hospital and Harvard Medical School in Boston, and Jacinthe Boulet, MD, CM, of the Montreal Heart Institute, in an .

"As newer pumps are introduced with differing circulatory profiles, pulsatility, and hemocompatibility configurations, studies of subtle neurological injury will be important in the future for evaluation of such technology," Mehra and Boulet wrote.

Cho's group identified 668 ENDURANCE program participants who had cognition -- comprising verbal learning, memory, executive function, language, and visuoconstructional function -- evaluated at baseline and at least once again after LVAD surgery.

This cohort had a mean age of about 64, and approximately four out of five patients were men. Two-thirds had received the HeartWare device.

Of the minority of patients who were cognitively intact at baseline, just over 10% declined in delayed memory and approximately another 10% declined in executive function at all three follow-ups.

Limitations to the study included its retrospective nature and the fact that only 257 patients had completed all the cognitive testing, the study authors acknowledged.

An important question, according to Mehra and Boulet, is whether results of cognitive tests such as the ones used in the study correlate with subclinical neurological injury, quality of life, and prognosis. Moreover, researchers have yet to find a useful biomarker of subtle neurological damage, they noted.

"Despite these remaining questions, clinicians should be comforted that the placement of durable VADs is not associated with marked aggregate changes to neurocognitive function in the absence of intercurrent overt neurological injury," they wrote.

"It is with this reassurance that we continue to observe advances in circulatory support technology that are associated with abrogation of neurological injury and provide a more forgiving, and eventually forgettable, interface," they concluded.

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