麻豆传媒

Left ventricular assist device (LVAD) recipients with hemolysis who are at risk of device thrombosis might do better with early replacement than waiting for response to more antithrombotic medication, a retrospective study found.

Hemolysis events -- defined by lactate dehydrogenase levels above 700 U/L -- were reported in 13.4% of LVAD patients in a two-center case series, about half of whom relied on amped-up antithrombotics alone as treatment.

By 1 year, that medical arm had three deaths (12.0%) and nine cerebrovascular events (36.0%), , of Montefiore Medical Center in New York, and colleagues reported in .

But the rest of the cohort, whose LVAD was surgically exchanged after failing medical therapy, appeared to have done better, with one death (4.2%) and two cerebrovascular events (8.3%) by 1 year.

"Hemolysis refractory to intensification of antithrombotic therapy identifies continuous-flow LVAD patients at major risk for cerebrovascular accident and death," the researchers wrote. "Early device exchange should be considered to minimize these risks."

Rates of 1-year freedom from cerebrovascular events or death after hemolysis were 87.5% in the surgical arm and 49.5% in the medical arm (P=0.027).

"Given the high incidence of complications during a watchful waiting approach, with nearly half the patients dying or experiencing cerebrovascular accident in the first 6 months post medical therapy alone, one might argue that exchange should be undertaken based on hemolysis parameters/treatment response alone and before the development of end-organ dysfunction or heart failure," Jorde and colleagues urged.

Device exchange has come a long way, according to , of Boston's Tufts Medical Center, and , of University of North Carolina at Chapel Hill.

"Early experiences with device exchange ... were associated with high perioperative morbidity and mortality. Additionally, exchange of continuous-flow LVADs after prolonged hemolysis resulted in high rates of death," they recalled in an .

"It is important to note that the surgical technique for HeartMate II device exchange has evolved," Jorde's group pointed out. "Recently reported favorable safety profiles and long-term outcomes after subcostal device exchange may provide added reassurance for lowering thresholds for early surgical intervention."

"In the absence of guideline recommendations and expert consensus statements, it must be emphasized that current published management practices all reserve pump exchange for hemodynamically significant pump thrombosis," the authors commented.

Now, "these data should assuage some of the fears that exist regarding earlier invasive management," the editorialists wrote. "Hemolysis, a harbinger of LVAD thrombosis, remains one of the most common and feared complications of LVAD therapy, occurring in as many as 33% of patients in the first year after device implantation."

Jorde's group conducted the analysis with observational data from 367 patients from two participating centers who were implanted with the HeartMate II continuous-flow LVAD between 2009 and 2014.

Most (87.5%) of the surgery arm had their hemolysis resolved with no adverse events, while the same could be said for only 52.0% of the medical therapy arm.

Even so, hemolysis returned in 28% of patients who had a successful device exchange. "This may indicate the presence of patient-related risk factors of thrombus formation that remain unchanged after device replacement, but could also result from leftover thrombus in outflow graft or inflow cannula not removed during device exchange," the authors noted.

Aside from its retrospective nature, the investigation was limited by the heterogeneity of the antithrombotics taken in the medical arm and the lack of clot histology. In addition, "the true clinical applicability of our results to recurrent events may be limited by the relatively low absolute number of recurrent events," Jorde and colleagues acknowledged.

"It is also evident that a 'one size fits all' strategy cannot be assumed for all hemolytic events. For instance, the pathophysiology of LVAD thrombosis is likely distinct for the HeartMate II and HVAD devices," added Kiernan and Katz.

With no randomized investigations on these complications to date, the duo noted that Jorde's study "highlights the need for collaborative data collection and prospective research to define best practices for the management of LVAD-related adverse events."