OVER-FIVE-MONTHS HEPARINLESS ECMO IN GOAT WITH A NEWLY DEVELOPED HEPARIN-COATED ECMO SYSTEM

Abstract

We developed an innovative ECMO system and successfully conducted over-5-months heparinless ECMO in animal trials. The system consists of oxygenators made of special hollow fiber in which micropores are blind-ended to prevent plasma leakage, and a durable centrifugal pump. The entire blood-contacting surface is treated with a novel heparin material (T-NCVC®) to impart excellent antithrombogenicity. Animal testing for venoarterial ECMO was undertaken in 16 adult goats (41–65 kg). Systemic anticoagulation was not conducted. All animals demonstrated good general condition during the scheduled ECMO periods (34–150 days). Bypass flow ranged 1.6–3.0 L/min on average, and O2 and CO2 transfer rates were 70–150 and 50–110 ml/min, respectivelyPlasma leakage was not observed in any case. The ACT and APTT levels were kept normal, and the blood heparin concentration was always less than detectable level. No substantial changes were seen in platelet count (35–52 ± 104 /μl), fibrinogen (200–300 mg/dl), and the other clotting factors. There was no evidence of thromboembolism at necropsy in any animal. In macroscopic and microscopic views, the hollow fibers were mostly free of thrombus, although a few clots were found mainly in the marginal area of the inlet and outlet ports. The other parts of the circuit were completely free of thrombus. In conclusion, the newly developed ECMO system has an ability to be used for prolonged heparinless ECMO.