Platelet activation and aggregation profile in prolonged external ventricular support

Houël, Rémi; Mazoyer, E.; Boval, Bernadette; Kirsch, Mathias; Vermès, Emmanuelle; Drouet, Ludovic; Loisance, D

doi:10.1016/j.jtcvs.2003.11.059

Cited by 44 publications

(30 citation statements)

References 26 publications

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“…Because pump thromboses still occur in some patients after LVAD implantation, a result of the withdrawal of anticoagulation medication, the activation of platelets, or both 29 in patients with various types of VADs, most centers choose an anticoagulation regime consisting of warfarin or phenprocoumon and a platelet inhibitor. However, a more adapted anticoagulation in LVAD therapy is warranted because of results and changes of the coagulation system.…”

Section: Discussionmentioning

confidence: 99%

Acquired von Willebrand Syndrome in Patients With an Axial Flow Left Ventricular Assist Device

Meyer

Malehsa²,

Bara³

et al. 2010

Circ: Heart Failure

260

149

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Background-Rotary blood pumps used as left ventricular assist devices (LVADs) allow for long-term support and may become suitable alternatives to heart transplantation. Effects of this technology on the coagulation system are not completely understood, leading to controversial anticoagulation protocols. Thus, we investigated the primary hemostasis in patients with chronic LVAD therapy. Methods and Results-Twenty-six outpatients received axial flow LVAD (HeartMate II; Thoratec) for a median support time of 4.5 months. In a cross-sectional protocol, platelet aggregation in response to ADP and epinephrine, von Willebrand antigen (vWF:AG), and collagen-binding capacity (vWF:CB) were obtained. Von Willebrand factor (vWF) multimer analyses were performed, and patients were screened for bleeding events. This analysis was repeated after removal of the device for transplantation or recovery (nϭ12) and after a median of 15.5 months in ongoing patients (nϭ11). In all patients on devices, severe impairment of platelet aggregation as well as a loss of large vWF multimers were found. In 10 patients, a decreased vWF:CB/vWF:AG ratio was observed. Bleeding episodes occurred with an incidence of 0.17 per patient-year. After removal of the device, normal patterns of platelet aggregation, multimer analysis, and vWF:CB/vWF:AG ratio were recorded. In the second analysis of ongoing patients, impairment of platelet aggregation and loss of large vWF multimers were verified. Conclusions-A diagnosis of von Willebrand syndrome type 2 was established in all patients after LVAD implantation, and bleeding events confirmed this finding. Reversibility of this condition was found after removal of the device. (Circ Heart Fail. 2010;3:675-681.)

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Section: Discussionmentioning

confidence: 99%

Acquired von Willebrand Syndrome in Patients With an Axial Flow Left Ventricular Assist Device

Meyer

Malehsa²,

Bara³

et al. 2010

Circ: Heart Failure

260

149

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“…Aspirin was started 24 h after surgery at a daily dose of 250 mg. Aspirin doses were subsequently adjusted to in vitro platelet function tests as reported previously [6].…”

Section: Anticoagulation Protocolmentioning

confidence: 99%

Impact of preoperative hemodynamic support on early outcome in patients assisted with paracorporeal Thoratec® ventricular assist device

Kirsch

Vermès

Radu

et al. 2008

European Journal of Cardio-Thoracic Surgery

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Background: Mechanical circulatory support has become a well-established procedure for some patients with cardiogenic shock. However, patient selection and timing of implantation remains critical. This retrospective study was undertaken to identify preoperative predictors of survival in ICU of patients requiring mechanical circulatory support. Methods: Between 1996 and 2006, 71 patients (61 men, 10 women, aged 41.6 AE 12.2 years) with primary cardiogenic shock were assisted using the paracorporeal Thoratec W VAD. Twenty-seven (38%) patients needed preoperative mechanical ventilation. Preoperative IV hemodynamic drug support included dobutamine in 63 (89%), vasopressors (adrenaline, noradrenaline or dopamine !5 mg/kg min) in 47 (66%), and intraaortic balloon counter-pulsation in 22 (31%) patients. Mean preoperative blood creatinine and total bilirubin levels were 162.2 AE 72.4 mmol/l and 36.4 AE 53.9 mmol/l, respectively. Results: Fifty-six (79%) patients required biventricular and 15 (21%) left ventricular support. Patients were assisted for a mean duration of 73.1 AE 93.6 days (extremes, 1-480 days). Twenty-five patients (35%) died while on support. Among these, 18 patients (25%) never recovered sufficiently to allow dismissal from ICU, and died after a mean of 15.4 AE 14.3 days. Logistic regression identified preoperative IV adrenaline as sole predictor for ICU death (OR, 5.48; 95% CI,, p = 0.012). Conclusions: The need for preoperative IV adrenaline therapy appeared to be the sole independent risk factor for death in ICU in patients assisted with the Thoratec W paracorporeal VAD. This suggests that, besides hemodynamic and metabolic consequences of cardiogenic shock, preoperative activation of the inflammatory cascade could influence the prognosis of patients undergoing mechanical circulatory support. #

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“…Circulating activated platelets have been measured in patients with stents, mechanical heart valves, and VADs as well as in patients suffering from acute myocardial infarction and ischemic stroke [7][8][9][10][11][12][13]. The presence of circulating activated platelets has been suggested as a marker for increased risk of thrombotic complications (10).…”

Section: Introductionmentioning

confidence: 99%

Flow Cytometric Assays for Quantifying Activated Ovine Platelets

et al. 2007

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Ovines are a common animal model for preclinical evaluation of cardiovascular devices including heart valves, endovascular grafts, and ventricular assist devices. Biocompatibility is essential to the success of these devices; however, tools to assess biocompatibility in ovines are limited. To address this need, antibodies that bind to activated human and bovine platelets and annexin V protein were evaluated for potential cross-reactivity to activated ovine platelets. These candidate markers were incubated with stimulated and quiescent ovine whole blood, and binding to platelets was quantified by flow cytometry. Several antihuman CD62P antibodies including one polyclonal antibody, three monoclonal antibodies, and annexin V selectively bound to activated ovine platelets. An assay to quantify platelet microaggregates was also developed. The availability of assays to quantify ovine platelet activation can increase the quality of biocompatibility data obtainable during preclinical development of artificial organs in the ovine model, potentially aiding in the evaluation of design refinements to enhance device biocompatibility. KeywordsBiocompatibility; Flow cytometry; Ovine platelets; Cardiovascular devices; Platelet activation Ovines are a common animal model for preclinical testing of blood-contacting cardiovascular devices including mechanical heart valves, endovascular grafts, and ventricular assist devices (VADs) (1-4). A critical aspect in the design of these devices is the evaluation of their blood biocompatibility. Yet, the biocompatibility data that can be obtained in ovine studies is limited due to a paucity of available assays for evaluating circulating blood elements during the implant period. In particular, there has only been one report on the use of flow cytometry to evaluate ovine platelet activation in platelet-rich plasma, and there have been no reports in the literature using such techniques to assess temporal platelet activation in ovines implanted with cardiovascular devices (5).Flow cytometry permits surface expression of platelet activation-dependent epitopes to be quantified, providing insight on circulating platelets not obtainable with platelet aggregometry and plasma assays for β-thromboglobulin and platelet factor 4 (6). Circulating activated platelets have been measured in patients with stents, mechanical heart valves, and VADs as well as in patients suffering from acute myocardial infarction and ischemic stroke [7][8][9][10][11][12][13]. The presence of circulating activated platelets has been suggested as a marker for increased risk of thrombotic complications (10). Previously, we have described several flow cytometric assays to quantify circulating activated bovine platelets and platelet microaggregates (14). These assays have been applied to assess circulating activated platelets in calves implanted with rotary VADs (14,15). The results demonstrate the ongoing presence of circulating activated platelets after the effects of surgery (without extracorporeal circulation) have di...

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Platelet activation and aggregation profile in prolonged external ventricular support

Abstract: In patients with an implanted external ventricular assist device, the platelet activation profile displays a persistent activation with a preserved reactivity associated with a persistent high inflammatory state and endothelial activation.

Cited by 44 publications

References 26 publications

Acquired von Willebrand Syndrome in Patients With an Axial Flow Left Ventricular Assist Device

Acquired von Willebrand Syndrome in Patients With an Axial Flow Left Ventricular Assist Device

Impact of preoperative hemodynamic support on early outcome in patients assisted with paracorporeal Thoratec® ventricular assist device

Flow Cytometric Assays for Quantifying Activated Ovine Platelets

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