Platelets and extra-corporeal membrane oxygenation in adult patients: a systematic review and meta-analysis

Abstract

Despite increasing improvement in extracorporeal membrane oxygenation (ECMO) technology and knowledge, thrombocytopenia and impaired platelet function are usual findings in ECMO patients and the underlying mechanisms are only partially elucidated. The purpose of this meta-analysis and systematic review was to thoroughly summarize and discuss the existing knowledge of platelet profile in adult ECMO population. All studies meeting the inclusion criteria (detailed data about platelet count and function) were selected, after screening literature from July 1975 to August 2019. Twenty-one studies from 1.742 abstracts were selected. The pooled prevalence of thrombocytopenia in ECMO patients was 21% (95% CI 12.9-29.0; 14 studies). Thrombocytopenia prevalence was 25.4% (95% CI 10.6-61.4; 4 studies) in veno-venous ECMO, whereas it was 23.2% (95% CI 11.8-34.5; 6 studies) in veno-arterial ECMO. Heparin-induced thrombocytopenia prevalence was 3.7% (95% CI 1.8-5.5; 12 studies). Meta-regression revealed no significant association between ECMO duration and thrombocytopenia. Platelet function impairment was described in 7 studies. Impaired aggregation was shown in 5 studies, whereas loss of platelet receptors was found in one trial, and platelet activation was described in 2 studies. Platelet transfusions were needed in up to 50% of the patients. Red blood cell transfusions were administered from 46 to 100% of the ECMO patients. Bleeding events varied from 16.6 to 50.7%, although the cause and type of haemorrhage was not consistently reported. Thrombocytopenia and platelet dysfunction are common in ECMO patients, regardless the type of ECMO mode. The underlying mechanisms are multifactorial, and understanding and management are still limited. Further research to design appropriate strategies and protocols for its monitoring, management, or prevention should be matter of thorough investigations.

Quantitative and Qualitative Platelet Derangements in Cardiac Surgery and Extracorporeal Life Support

“…Abrams first stated that platelet count reduction was mostly due to the severity of the disease of patients rather than related to the duration of ECMO support [57]. In a recent meta-regression, we confirmed that a worsening in thrombocytopenia was independent of the number of days on ECMO [56]. However, we speculated that after few days the inflammatory response induced by ECMO might not affect the freshly generated platelets due to the beginning of an endothelization mechanism of the circuit [56,61,62].…”

“…The ECMO mode also does not seem to influence the degree of thrombocytopenia [56]. After analyzing the available evidence in the literature, we estimated a comparable platelet count decrease in almost 25% and 23% of adult V-A and V-V ECMO subjects, respectively [56].…”

“…The Extracorporeal Life Support Organization (ELSO) anticoagulation guideline recommends the administration of antithrombotic therapy during ECMO; unfractionated heparin (UFH) is widely administered [54,55]. The prevalence of HIT in adult ECMO patients is estimated at 3.7% with a similar prevalence between V-A and V-V ECMO [55,56]. However, this result could be biased by prompt HIT recognition and switching to alternative anticoagulants [56].…”

“…The prevalence of HIT in adult ECMO patients is estimated at 3.7% with a similar prevalence between V-A and V-V ECMO [55,56]. However, this result could be biased by prompt HIT recognition and switching to alternative anticoagulants [56]. Frequently, physicians treat a patient by just thinking about HIT and without a solid diagnosis.…”

Heparin-Induced Thrombocytopenia in Severe COVID-19

“…Although thrombocytopenia is frequent in critically ill patients, the incidence of HIT is relatively rare (<1% 3 ; up to 3.7% in patients supported by extracorporeal membrane oxygenation). 4 In a previously published cohort of 105 patients supported by venovenous extracorporeal membrane oxygenation, we reported an incidence of HIT of 2% 5 compared with 3 among 14 patients (21%) during the COVID-19 pandemic. We compared this cohort with a control cohort of patients in the intensive care units of our centers during a 6-month period from January 1 to June 1, 2019: 447 patients were admitted to our centers, with 58.8% of patients requiring mechanical ventilation and 13 patients (5%) supported by extracorporeal membrane oxygenation.…”