Article

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: 3.45). 01/2009; 87(1):131-7. DOI: 10.1016/j.athoracsur.2008.10.027
Source: PubMed

ABSTRACT 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.

2 Bookmarks
 · 
190 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Continuous-flow left ventricular assist devices (LVAD) have become standard therapy option for patients with advanced heart failure. They offer several advantages over previously used pulsatile-flow LVADs, including improved durability, less surgical trauma, higher energy efficiency, and lower thrombogenicity. These benefits translate into better survival, lower frequency of adverse events, improved quality of life, and higher functional capacity of patients. However, mounting evidence shows unanticipated consequences of continuous-flow support, such as acquired aortic valve insufficiency and acquired von Willebrand syndrome. In this review article we discuss current evidence on differences between continuous and pulsatile mechanical circulatory support, with a focus on clinical implications and potential benefits of pulsatile flow.
    Croatian Medical Journal 12/2014; 55(6):609-620. · 1.25 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Left ventricular assist device (LVAD) thrombosis is a life-threatening complication. Multiple case reports describe successful nonsurgical management with thrombolytics, aggressive antiplatelet therapy, or percutaneous catheter-directed thrombectomy. However, consensus management of LVAD thrombosis has not been established and guidelines are urgently needed. In order to raise awareness of nonsurgical treatment options, we review the current strategies for the clinical diagnosis, management, and prevention of LVAD thrombosis.
    Journal of Cardiac Surgery 11/2013; · 1.35 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Objective Describe dental protocol for treating in the intensive care unit, end-stage heart-failure patients having ventricular assist devices (VAD) emergently implanted as a “bridge to heart transplantation”. This protocol permitted the rendering of safe and effective dental care in this setting and did not result in near-term (1-30 days) excessive hemorrhage, local and systemic infection, or contamination of the VAD. Study Design Descriptive cross-sectional study by UCLA Hospital Dental Service delineating dental care of 9 patients (mean age 50±12.9 years) with Class IV Stage D heart-failure. Results Nine patients, 22 days (mean) after VAD placement, received dental treatment after intravenous prophylactic antibiotics and maintenance of prior anticoagulation, antiplatelet or antithrombin regimen. Eight patients had extractions (4 mean: range 1-12) and one of them also required scaling and root planing (SRP) of the remaining teeth. A ninth individual only required SRP of four quadrants. No adverse outcomes developed. Conclusions Emergent removal of active dental disease in patients with VAD awaiting heart transplantation can be safely accomplished using established protocols with extended vigilance.
    Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontology 08/2014; · 1.50 Impact Factor

Full-text (2 Sources)

Download
105 Downloads
Available from
Jun 1, 2014