PATIENTS with advanced heart failure receiving long-term left ventricular assist device (LVAD) support developed progressive changes in blood clotting function over time, despite showing overall improvements in cardiac and organ function, according to new research.
Continuous-Flow LVAD Therapy
Continuous-flow LVADs are increasingly used to support patients with severe heart failure, either while awaiting heart transplantation or as long-term therapy.
Although these devices improve survival, patients remain at risk of major complications including bleeding, pump thrombosis, and ischaemic stroke. Researchers therefore investigated how prolonged LVAD support affects coagulation pathways over several years.
LVAD Therapy and Long-Term Coagulation Changes
The study recruited 85 patients receiving continuous-flow LVAD therapy, though only 22 completed all scheduled follow-up visits and were included in the final analysis. Researchers assessed thrombin generation using the Calibrated Automated Thrombogram (CAT) assay at baseline, 3–4 months, 6–12 months, and then every 6 months thereafter.
Over time, investigators observed a progressive shift towards a hypocoagulable state, meaning the blood appeared less able to clot normally.
Thrombin generation lagtime increased significantly, while endogenous thrombin potential and peak thrombin concentration declined (P<0.001). Persistent markers of fibrinolytic activity, the process involved in clot breakdown, were also detected throughout long-term follow-up.
Heart Failure Markers Improved Despite Haemostatic Abnormalities
Importantly, these coagulation changes occurred alongside improvements in several markers associated with heart failure severity and organ function.
Albumin and haemoglobin concentrations increased during LVAD support, while bilirubin, creatinine, and N-terminal pro-B-type natriuretic peptide levels declined significantly (P<0.05). These findings suggest improved cardiac performance and better kidney and liver perfusion during treatment.
However, despite these broader physiological improvements, the altered coagulation profile raised concerns about ongoing disturbances in haemostasis during prolonged mechanical circulatory support.
Clinical Risk
Researchers did not identify a significant association between CAT assay parameters and adverse clinical events within the study population.
Nevertheless, the findings suggest that continuous-flow LVAD therapy may progressively alter coagulation balance independently of stable anticoagulant and antiplatelet treatment regimens.
The mechanisms underlying these haemostatic changes remain unclear and require further investigation.
Implications for Future LVAD Monitoring
The study was limited by its relatively small sample size and incomplete long-term follow-up. However, it provides rare longitudinal insight into how coagulation function evolves during extended LVAD support.
Future studies may help determine whether serial thrombin generation monitoring could support more personalised anticoagulation strategies or identify patients at increased risk of bleeding and thrombotic complications during LVAD therapy.
Reference
Kuczaj A et al. Longitudinal assessment of thrombin generation using calibrated automated thrombography in patients with continuous-flow left ventricular assist devices over a five-year period. Sci Rep. 2026;DOI:10.1038/s41598-026-51694-6.
Featured image: jaeng on Adobe Stock
