New left ventricular thrombus during temporary percutaneous microaxial left ventricular assist device support: cumulative incidence, device management, and anticoagulation control
S Singh, A Kocherlakota, S Ohira, D Al-Rameni, A JaiswalAbstract
Background/Introduction
Temporary percutaneous microaxial left ventricular assist device (microaxial LVAD) support is increasingly used as a bridge to advanced therapies. New left ventricular thrombus (LVT) can occur during the support and may increase thromboembolic and device-related risk, yet contemporary data describing its frequency, management pathways, and anticoagulation control around diagnosis are limited.
Purpose
To quantify the cumulative incidence of new LVT during microaxial LVAD support, describe device management strategies (initial device selection, upgrade, exchange, or escalation), and evaluate anticoagulation control around the time of LVT diagnosis and subsequent bridge outcomes.
Methods
We retrospectively reviewed 260 consecutive adults supported with microaxial LVAD as a bridge to advanced therapies; seven developed new LVT. Median age was 58 years (range 35–72) and six were male. Outcomes were either heart transplantation (HT) or death. Anticoagulation control was assessed using time in therapeutic range (TIR) as follows: for patients receiving unfractionated heparin, anti-Xa values from the 48 hours prior to LVT diagnosis were used to calculate time in range (TIR_hep) and the proportion below target; for patients transitioned to bivalirudin after diagnosis, activated partial thromboplastin time (aPTT) values from the first 48 hours were used to quantify early time in range (TIR_biv), and values from the final 48 hours prior to outcome were used to summarise late control (Figure).
Results
New LVT occurred in 7/260 patients (2.7%). Six patients began on a lower-support microaxial device; three required upgrade to higher support and one was escalated to extracorporeal mechanical circulatory support. Heparin was frequently subtherapeutic before diagnosis, with a median TIR_hep (−48 h) of ≈15% among six evaluable patients. Following LVT diagnosis, five patients were transitioned to bivalirudin. Early control on bivalirudin was limited (median TIR_biv during the first 48 h was ≈33%), while late control improved (≈65%). Notably, very low early TIR_biv was observed among patients who died, whereas higher early and late TIR_biv were observed in several patients who successfully bridged to HT. Complications included pump thrombosis requiring device exchange (n=2), transient ischaemic attack (n=1), and stroke (n=1). Overall, three patients (43%) underwent HT, while four (57%) died–three from progressive shock and one from embolic stroke with intracranial haemorrhage.
Conclusion(s)
In a large cohort receiving microaxial LVAD support, new LVT was uncommon (2.7%) but carried substantial thromboembolic and device-related complications. Despite LVT, nearly half of patients still achieved HT. Optimising early anticoagulation after diagnosis, alongside a device-first strategy (upgrade, exchange or escalation), may help preserve the feasibility of bridging and warrants further evaluation in larger studies.For image description, please refer to the figure legend and surrounding text.