Prevalence and outcome of heparin-induced thrombocytopenia diagnosed under veno-arterial extracorporeal membrane oxygenation: a retrospective nationwide study

PURPOSE

Thrombocytopenia is a frequent and serious adverse event in patients treated with veno-arterial extracorporeal membrane oxygenation (VA-ECMO) for refractory cardiogenic shock. Similarly to postcardiac surgery patients, heparin-induced thrombocytopenia (HIT) could represent the causative underlying mechanism. However, the epidemiology as well as related mortality regarding HIT and VA-ECMO remains largely unknown. We aimed to define the prevalence and associated 90-day mortality of HIT diagnosed under VA-ECMO.

METHODS

This retrospective study included patients under VA-ECMO from 20 French centers between 2012 and 2016. Selected patients were hospitalized for more than 3 days with high clinical suspicion of HIT and positive anti-PF4/heparin antibodies. Patients were classified according to results of functional tests as having either Confirmed or Excluded HIT.

RESULTS

A total of 5797 patients under VA-ECMO were screened; 39/5797 met the inclusion criteria, with HIT confirmed in 21/5797 patients (0.36% [95% CI] [0.21-0.52]). Fourteen of 39 patients (35.9% [20.8-50.9]) with suspected HIT were ultimately excluded because of negative functional assays. Drug-induced thrombocytopenia tended to be more frequent in Excluded HIT at the time of HIT suspicion (p = 0.073). The platelet course was similar between Confirmed and Excluded HIT (p = 0.65). Mortality rate was 33.3% [13.2-53.5] in Confirmed and 50% [23.8-76.2] in Excluded HIT (p = 0.48).

CONCLUSIONS

Prevalence of HIT among patients under VA-ECMO is extremely low at 0.36% with an associated mortality rate of 33.3%, which appears to be in the same range as that observed in patients treated with VA-ECMO without HIT. In addition, HIT was ultimately ruled out in one-third of patients with clinical suspicion of HIT and positive anti-PF4/heparin antibodies.

First steps to improve cotton crop management in Thailand

Thai cotton growers yearly face serious pest problems consisting of heavy infestation associated with resistance to pesticides leading to expensive and harmful pest control practices. Thanks to a multi discipline research work carried out from 1991 to 1996, a decision-oriented model for cotton crop management was developed and compared to farmers' practices during the 1988 cotton growing season 1998 in Klang Hat district, Thailand. This model, based on plant monitoring, involved a new cotton cultivar (DORA 11 as a replacement for Sri Samrong 60), seed treatment with imidacloprid (at 3.5 g of a.i./kg of seeds), a threshold-based spray of mepiquat chloride, a cotton growth regulator (Pix at 1.5 l/ha) and a set of rules to selectively control with chemical and biological insecticides the major pests the American bollworm (Helicoverpa armigera Hübner) and the cotton leafhopper (Amrasca biguttula biguttula Ishida). This package was more friendly towards environment than farmers' practices since seed treatment does not harm beneficials at the beginning of cotton growing season while 1 and 5 sprays were saved against respectively the American bollworm and sucking pests and more than 50% of the sprays directed against American bollworms involved biological insecticides (Bacillus thuringiensis toxins potentialized by a low dosage of endosulfan). Threshold-based sprays against the main pests, the use of a cotton growth regulator, earliness of cotton cultivar and seed treatment were accountable for savings in pesticide sprays. Involving a biological insecticide and endosulfan at the beginning of cotton growing season and using the same quantity of active ingredient at each spray during the cotton growing season also improved the management of pyrethroid resistance in American bollworm populations was also. There was no significant difference between yields inside farmers' fields and innovation plots. However, thanks to cheaper pest control practices economic results were better. Lastly few improvements of this package are proposed.