Ventrikuläre Langzeitunterstützung mit implantierbaren kontinuierlichen Flusspumpen: Auf dem Weg zum Goldstandard in der Therapie der terminalen Herzinsuffizienz

A Not-Motorized Implantable Device for Partial Circulatory Support: A Proof of Concept Experiment

A fully implantable circulatory assistance device without external connection and lifetime energy supply can eliminate a significant source of morbidity and mortality for patients. Here, we present and discuss concept and preliminary results of an original project for a not-motorized, fully implantable circulatory assistance device. The not-motorized implantable circulatory assistance device (NICA) has been tested into a cardiac simulator that was conceived according to the FDA and ISO standards. The instrumentation incorporated to the cardiac simulator includes probes for the aortic pressure (AoP) proximally to the device, a temperature control system, and one electromagnetic flowmeter to acquire the flow rate (AoF) proximally to the device. A control software allows to modulate the drive parameters such as velocity, acceleration, number of revolutions, the stroke volume, and the heart rate. Experiments have been performed with three different circuit resistances: 2100 dyn s/cm5, 1400, and 700. The AoF increased in the assisted cycles: 71% at 2100 dyn s/cm5, 67% at 1400 dyn s/cm5, and 25% at 700 dyn s/cm5. NICA performs a partial but significant support of AoF without energy supply. The improvement of AoF increases with the increasing of vascular resistances. The feedback received by this preliminary bench experiment acted as a preliminary proof of concept of this new device.

Comparison of novel physiological load-adaptive control strategies for ventricular assist devices

Terminal heart failure (HF) is the most prevalent cause of death in the Western world and the implantation of a left ventricular assist device (LVAD) has become the gold standard therapy today. Most of the actually implanted devices are driven at a constant speed (CS) regardless of the patient’s physiological demand. A new physiological controller [power ratio (PR) controller], which keeps a constant ratio between LVAD power and left ventricular power, a previous concept [preload responsive speed (PRS) controller], which adds a variable LVAD power to reach a defined stroke work, and a CS controller were compared with an unimpaired ventricle in a full heart computer simulation model. The effects of changes in preload, afterload and left ventricular contractility are displayed by global hemodynamics and ventricular pressure-volume loops. Both physiological controllers demonstrated the desired load dependency, whereas the PR controller exceeded the PRS controller in response to an increased load and contractility. Response was inferior when preload or contractility was decreased. Thus, the PR controller might lead to an increased exercise tolerance of the patient. Additional studies are required to evaluate the controllers

[Rehabilitation standards for follow-up treatment and rehabilitation of patients with ventricular assist device (VAD)]

The increasing use of ventricular assist devices (VADs) in terminal heart failure patients provides new challenges to cardiac rehabilitation physicians. Structured cardiac rehabilitation strategies are still poorly implemented for this special patient group. Clear guidance and more evidence for optimal modalities are needed. Thereby, attention has to be paid to specific aspects, such as psychological and social support and education (e.g., device management, INR self-management, drive-line care, and medication).In Germany, the post-implant treatment and rehabilitation of VAD Patients working group was founded in 2012. This working group has developed clear recommendations for the rehabilitation of VAD patients according to the available literature. All facets of VAD patients' rehabilitation are covered. The present paper is unique in Europe and represents a milestone to overcome the heterogeneity of VAD patient rehabilitation.