[Improvements in implantable mechanical circulatory support systems : literature overview and update]

In recent years, ventricular assist devices (VAD) supporting the left (LVAD), the right (RVAD) or both ventricles (BVAD) have rapidly emerged as the standard of care for advanced heart failure patients. Both the numbers and ages of patients in which they are used are rising worldwide, especially when used as a permanent support (bridge to destination, BTD). Due to the continuing lack of donor organs, these devices now represent a viable alternative to bridge patients to transplantation (BTT), with a 1-year survival rate of 86%. BTD, especially in long-term support, might be a valid, and the sole, option for those patients in whom heart transplantation is contraindicated. Patient selection, pre- and intra-operative preparation, as well as the timing of VAD implantation are important factors critical to successful circulatory support. While BTT remains the goal in the majority of patients, the number of permanent VADs (i. e. BTD) is rising significantly. Although explantation of a VAD system as a bridge to recovery (BTR) can be considered in only a small number of patients, it represents a very special part of this therapy modality.

Argatroban anticoagulation for heparin induced thrombocytopenia in patients with ventricular assist devices

BACKGROUND

Patients receiving implantation of ventricular assist devices (VAD) suffer a high incidence of heparin induced thrombocytopenia (HIT); the occurrence of this condition is associated with increased complications and worse outcomes. We report our experience in the management of patients who were diagnosed with HIT either before (HITpre) or after (HITpost) implantation of VAD with argatroban, a direct thrombin inhibitor.

METHODS

This retrospective analysis assessed data of VAD patients diagnosed with HIT at Deutsches Herzzentrum Berlin between November 2005 and April 2009. Argatroban dose requirements, anticoagulation efficacy and adverse events (death, thromboembolism, bleeding) were recorded. Procedural success (discharge from the hospital, heart transplantation, or recovery of the failing heart) was also assessed.

RESULTS

Twenty-seven patients were identified (11 HITpre, 16 HITpost). Argatroban was effective in obtaining adequate anticoagulation with a reduced dose regimen (0.02-0.42 mcg/Kg/min starting dose; 0.02-1.5 mcg/Kg/min maintenance dose). We noted 5 thromboembolic complications (18%), 6 cases of major bleeding (22%) and 5 deaths (18%), all cause composite adverse end point occurring in 40% of patients. Procedural success was obtained in 81% of patients (92% HITpre, 69% HITpost). As compared to historical controls of patients treated with lepirudin in the period 2000-2005, results were significantly improved.

CONCLUSION

Argatroban anticoagulation is feasible in patients with HIT after VAD implantation, without increasing bleeding risk. Its impact in terms of survival should be reviewed also in the light of the technological improvements of assist devices.