Thrombosis related to the placement of a left ventricular assist device (LVAD) should be managed according to the location and severity of the clot, a single-center series suggested.
The retrospective analysis included 557 consecutive participants treated with the HeartWare LVAD at a German center from 2009 to 2015. Their outcomes and treatment strategy success was reported by , of IRCCS San Raffaele Scientific Institute in Italy, and colleagues online in the .
Pre-pump: For one, blood flow abnormalities as measured by an LVAD can originate at the inflow cannula, causing a pre-pump thrombus. This occurred at a rate of 0.037 events per patient-year in the series. Normal blood flow was re-established for 85% of cases. In this scenario, "pump stop under protection of the carotid arteries offers the possibility of less invasive treatment. In our experience this was completely successful," the authors wrote "The time frame for successful washout is a matter of hours; later lysis is a viable option, but the success rate was lower (56%)."
Intra-pump: Within the pump itself was the site of thrombosis for 0.1 events per patient-year, with the operators achieving a 84% success rate in treating these overall. When intra-pump events occur, "pump exchange is the definitive treatment" because early intervention is important, Scandroglio's group urged. "Thrombolysis plays a secondary role in managing this complication," they added, although it can be successful "if started immediately after the first signs of intra-pump thrombosis (power increase or acoustic signals or hemolysis) appear."
Post-pump: Much rarer were post-pump thrombi located at the outflow graft or stenosis of the anastomosis to the aorta, which were found in 0.006 cases per patient-year.
Scandroglio and colleagues suggested that "kinking of the outflow tract can be treated by stenting alone, and thrombosis of the outflow tract by stenting with a covered stent while using cerebral endovascular protection." Indeed, both such stenting attempts in the cohort ended in normal blood flow.
"Despite an 85% success rate in restoration of normal blood flow through the device, only two-thirds of the patients who entered the hospital with VAD thrombosis survived and were discharged," noted , of Duke University Medical Center in Durham, N.C.
In an , he argued that "although ventricular assist device therapy has undeniably altered the prognosis of end-stage heart failure and restored patients to more normal functionality, it is not without cost to the patient, their families, and the healthcare delivery system."
Rogers recalled the INTERMACS study, which "recently reported that 70% of patients with LVAD have an infection, bleeding, device malfunction, stroke, or death within 1 year following implantation. These patients are rehospitalized two to three times annually for adverse events."
"Mechanical circulatory support will not [achieve] its ultimate potential and goal of delivering outcomes competitive to cardiac transplantation until refinements in device technology and management strategies mitigate adverse events," he wrote.
Disclosures
The study was funded by the German Heart Center Berlin.
Scandroglio and Rogers disclosed no relevant relationships with industry.
One author declared relationships with HeartWare, Berlin Heart, Edwards Lifesciences, Aesculap, and Boston Scientific.
Primary Source
Journal of the American College of Cardiology
Scandroglio AM, et al "Diagnosis and treatment algorithm for blood flow obstructions in patients with left ventricular assist device" J Am Coll Cardiol 2016; DOI: 10.1016/j.jacc.2016.03.573.
Secondary Source
Journal of the American College of Cardiology
Rogers JG " Managing VAD complications: our growth industry" J Am Coll Cardiol 2016; DOI: 10.1016/j.jacc.2016.04.011.