Early elevations in pump power with the HeartMate II left ventricular assist device do not predict late adverse events.

Background: The aim of this study was to evaluate the prevalence of early pump power elevation events in patients with the HeartMate II (HMII) and its impact on subsequent development of stroke and pump thrombosis.

Methods: We analyzed >45,000 measurements of pump power and pump speed measured during the initial hospitalization period and >12,000 follow-up measurements obtained from 138 consecutive patients implanted with a HMII between January 2009 and December 2012. An early power elevation (PEL) event was defined as power ≥10 W within the first 14 post-operative days. Patients were divided into two groups: those with an early PEL event and those without (NP).

Results: Median follow-up duration was 316 (range 2 to 1,264) days. Twenty-seven (20%) patients had early PEL events that lasted for a total duration of 4 (range 1 to 77) hours per patient. Pump speed averaged 9,400 rpm in both groups. Although patients in the PEL group had higher median power (7.1 [6.0 to 9.9] W vs 6.7 [5.7 to 7.8] W, p < 0.001) in the immediate post-operative period, there was no difference between the two groups noted at first follow-up (6.6 [5.9 to 8.7] W vs 6.7 [5.5 to 7.7] W, p = 0.940). No differences in the prevalence of hemorrhagic stroke (4% vs 3%, p = 0.56), ischemic stroke (0% vs 4%, p = 0.41), hemolysis (7% vs 5%, p = 0.32), pump thrombosis (7% vs 4%, p = 0.21) or survival (76% at 1 year in both groups) were found between the two groups.

Conclusions: In this single-center experience, PEL events that occurred early all resolved by discharge. No relationship was found between early PEL events and subsequent development of pump thrombosis, hemorrhagic stroke or ischemic stroke.