Use of a Novel Bicarbonate-Based Impella 5.5 Purge Solution in a Coagulopathic Patient

The Impella 5.5 with SmartAssist (Abiomed; Danvers, MA) is a life-saving treatment option in acute heart failure which utilizes a continuous heparin purge solution to prevent thrombosis. In patients with contraindications to heparin, alternative anticoagulation strategies are required. We describe the stepwise management of anticoagulation in a coagulopathic patient with persistent cardiogenic shock following a coronary artery bypass procedure who underwent Impella 5.5 placement. A direct thrombin inhibitor-based purge solution was utilized while evaluating for heparin-induced thrombocytopenia. Use of a novel bicarbonate-based purge solution (BBPS) was successfully used due to severe coagulopathy. There were no episodes of pump thrombosis or episodes of severe bleeding on the BBPS and systemic effects of alkalosis and hypernatremia were minimal.

Calibrated automated thrombogram II: removing barriers for thrombin generation measurements

Background Thrombin generation (TG) assessed by Calibrated Automated Thrombogram (CAT-I) reflects the overall capacity of plasma to generate thrombin, thus evaluating the balance between the anti- and procoagulant processes. However, with this method the calibrator curve is usually not measured until completion which has a severe impact on the calculation of the TG parameters, especially under conditions where almost all substrate is consumed. In addition, direct thrombin inhibitor (DTI) cannot be present in the calibration sample due to inhibition of the calibrator. We have developed a modified TG assay (CAT-II) and performed head-to-head comparison with the CAT-I method using the same fluorometer. Furthermore, we have compared our CAT-II method to a new automated TG instrument (ST®-Genesia) using the same calibration method. Methods TG was assessed with CAT-I and CAT-II using the same fulorometer and with ST®-Genesia in control plasma and plasma containing different anticoagulants (dabigatran, rivaroxaban, apixaban) and plasmas to which common interfering substances, bilirubin, hemoglobin and lipids were added. In CAT-I, calibration was against the same plasma containing calibrator in the presence of fluorogenic substrate (Z-GGR-AMC). In contrast, CAT-II method and ST®-Genesia used a standard concentration of thrombin in buffer and 7-amino-4-methylcoumarin (AMC) in a separate plasma sample for calibration. Results TG obtained from CAT-I using anticoagulant-free plasmas was lower compared with TG from CAT-II but both methods demonstrated an intra-assay variation less than 5% on all measured parameters. When comparing the two different calibration methods in the presence of different anticoagulants, a high correlation was seen in the presence of rivaroxaban and apixaban (R2 > 0.97), but not with dabigatran, a direct thrombin inhibitor. CAT-II method showed dose-dependent inhibition of TG in the presence of dabigatran, while CAT-I was not able to detect it. Both methods were able to correct for the interfering substances. Conclusions Our results showed high similarity between the results of CAT-I and CAT-II method when it is applied in control plasmas and plasmas not inhibited with a direct thrombin inhibitor. Furthermore, both the CAT-II method and ST-Genesia using the same calibration method were able to detect the effect of all oral anticoagulants. Taken together, applying a new calibration method is a significant improvement for monitoring patients on direct thrombin inhibitors while not introducing any bias to results obtained on other types of samples.

Use of a direct thrombin inhibitor for intraoperative anticoagulation during endovascular abdominal aortic aneurysm repair in a patient with heparin-induced thrombocytopenia

In the issue the authors report brief literature review and the case of use of bivalirudin as an alternative intraoperative anticoagulant for endovascular abdominal aortic aneurysm repair in a patient with heparin-induced thrombocytopenia.

A Case of Liver Failure Due to Dabigatran Treated with Venovenous Hemodiafiltration and Idarucizumab

Dabigatran etexilate, a direct thrombin inhibitor, was recently introduced in clinical use to prevent thromboembolic events in patients with risk factors (such as non-valvular atrial fibrillation or deep vein thrombosis). Dabigatran is not recommended in patients with creatinine clearance below 30 mL/min. More than 85% of the drug is eliminated by the renal route while the remaining part via the enteral route. Acute renal failure can result in an unexpected increase in serum levels of Dabigatran. In elderly, renal dysfunction, co-morbidity, and concomitant intake of different drugs could make the dosage of Dabigatran challenging. We present a case of an elderly man who suffered a severe accidental dabigatran intoxication with acute liver toxicity recovered after dialytic treatment and Idarucizumab.