Platelet Dysfunction in Outpatients With Left Ventricular Assist Devices

Division of Cardiothoracic and Vascular Anesthesia and Intensive Care, Medical University of Vienna, Vienna, Austria.
The Annals of thoracic surgery (Impact Factor: 3.85). 01/2009; 87(1):131-7. DOI: 10.1016/j.athoracsur.2008.10.027
Source: PubMed


Thromboembolic and bleeding complications in outpatients with a left ventricular assist device are common and can be detrimental. A meticulous balance between anticoagulant and procoagulant factors is therefore crucial. However, in contrast to routinely performed plasmatic coagulation tests, platelet function is hardly ever monitored although recent reports indicated platelet dysfunction. We therefore differentially evaluated platelet function with four commonly used point-of-care devices.
In a cross-sectional design platelet function was assessed in 12 outpatients and 12 healthy matched volunteers using thrombelastography platelet mapping, thromboelastometry, platelet function analyzer, and a new whole blood aggregometer (Multiplate).
Phenprocoumon produced an international normalized ratio of 3.5. It was associated with a twofold prolongation in the thromboelastometry clotting time (p < 0.001). Platelet function under high shear was severely compromised: collagen adenosine diphosphate closure times were 2.5-fold longer in patients than in volunteers (p < 0.001), and 50% of patients had maximal collagen adenosine diphosphate closure time values. Although antigen levels of von Willebrand factor were 80% higher in patients (p < 0.001), von Willebrand factor-ristocetin was subnormal in 5 of 12 patients. Ristocetin-induced aggregation was also threefold higher in volunteers (p < 0.001), indicating an additional functional defect of platelets affecting the glycoprotein Ib-von Willebrand factor axis. The von Willebrand factor multimer pattern in patients also appeared abnormal.
Multimodal antiplatelet monitoring showed markedly impaired platelet function in patients with a left ventricular assist device. Platelet dysfunction under high shear rates and abnormal ristocetin-induced aggregation is only partly attributable to low von Willebrand factor activity. These findings resemble the acquired von Willebrand syndrome that is associated with microaggregate formation and enhanced bleeding.

Download full-text


Available from: Henrik Fischer, Jan 06, 2014
  • Source
    • "Device support was associated with frequent adverse events and extended ICU and hospital stays. Bleeding was particularly common (70%), reflecting the need for anticoagulation , the presence of the multiple vascular suture lines and an ongoing device-related coagulopathy [21,22]. Almost half the patients required renal support therapy, and two patients suffered embolic strokes and died on support a short time later. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Primary graft failure is the most common cause of mortality early after heart transplantation. The availability of relatively low-cost short-term mechanical support devices has altered the management of primary graft failure but there are few data on clinical outcome. Here, we describe the UK experience with Levitronix CentriMag support following heart transplantation across multiple centres. Data for all adult heart transplants and all CentriMag devices used within 30 days of heart transplantation in the UK between November 2003 and July 2008 were collected. Transplant characteristics were compared for those who did and did not receive CentriMag support, and device outcomes and survival rates were summarised. A total of 572 heart transplants were performed in this period. As many as 38 patients (6.6%) were implanted with CentriMag devices for primary graft failure. Four patients received extracorporeal membrane oxygenation concurrently and were excluded from further analysis. There were no significant differences in transplant characteristics between the patients who received CentriMag support and those who did not. Twelve patients were explanted; nine survived but three died shortly afterwards. Five underwent acute retransplantation; two survived and three died. Seventeen patients died on support. The 30-day and 1-year survival rates were 50% (95% confidence interval (CI) 32-65%) and 32% (95% CI 18-48%), respectively. Patients who previously had a bridge-to-transplant ventricular assist device (VAD) had significantly better survival than those who did not (1-year survival 71% vs 22%, p = 0.029). Primary graft failure remains an important early complication of heart transplantation. Levitronix CentriMag support led to the salvage of 32% of patients with severe allograft failure.
    Preview · Article · Apr 2011 · European journal of cardio-thoracic surgery: official journal of the European Association for Cardio-thoracic Surgery
  • [Show abstract] [Hide abstract]
    ABSTRACT: During September-October in 1995, the Environmental Technology Laboratory (ETL) conducted the Coastal Oceans Probing Experiment COPE off the Oregon coast. During this experiment, a 5-mm scanning radiometer was deployed on a research vessel. In this report, a summary of the obtained results is presented
    No preview · Conference Paper · Jun 1996
  • [Show abstract] [Hide abstract]
    ABSTRACT: The aim of the study is to develop inversion methods for spaceborne SAR images of the boreal forests. The parameters of interest are stem volume (biomass), forest and land-cover types, soil and vegetation moisture. The previously developed forest stem volume/soil moisture retrieval algorithm was tested by producing soil moisture maps for large test areas. The textural information of a seasonal set of ERS-1 SAR images was studied with the first and second order statistical measures. These measures had a higher information value than intensity values (or their principal components) for the forest and land type classification. The multitemporal approach was beneficial for the application of textural measures and the textural parameters significantly improved the classification of land-use and forest types
    No preview · Conference Paper · Jun 1996
Show more