Development of a database of patients supported by ventricular assist devices

An innovative adaptive control strategy for sensorized left ventricular assist devices

Nowadays advanced heart failure is mainly treated through heart transplantation. However, the low availability of donors makes the research of alternative therapies urgent. Continuous-flow left ventricular assist devices (LVADs) are going to assume a more significant role in assisting the failing heart. A recent challenge in clinical practice is the possibility to use LVAD as long-term therapy rather than as a bridge to transplantation. For this reason, more comfortable devices, able to dynamically adapt to the physiological cardiac demand in relation to the patient activity level, are needed in order to improve the life quality of patients with implants. Nevertheless, no control system has been developed yet for this purpose. This work proposes an innovative control strategy for a novel sensorized LVAD, based on the continuous collection of physical and functional parameters coming from implantable sensors and from the LVAD itself. Thanks to the proposed system, both the patient and the LVAD conditions are continuously monitored and the LVAD activity regulated accordingly. Specifically, a Proportional Integrative (PI) and a threshold control algorithms have been implemented, respectively based on flow and pressure feedbacks collected from the embedded sensors. To investigate the feasibility and applicability of this control strategy, an on-bench platform for LVADs sensing and monitoring has been developed and tested.

Impact of Heparin-Induced Thrombocytopenia on Outcome in Patients with Ventricular Assist Device Support: Single-Institution Experience in 358 Consecutive Patients

BACKGROUND

Cardiac surgical patients are at an approximate 1% to 2% risk of experiencing heparin-induced thrombocytopenia (HIT), a severe immune-mediated disease that is associated with thromboembolic events. We assessed the occurrence of this disease and its influence on clinical outcome in patients after implantation of a ventricular assist device (VAD).

METHODS

This retrospective analysis assessed data from our adult patient VAD program between the years 2000 and 2005. Patients were divided into three groups: those without confirmed HIT ((non)HIT), those in whom the diagnosis of HIT was made before VAD implantation (HIT(pre)), and those who experienced HIT after VAD implantation (HIT(post)). End points assessed were procedural success, as defined by discharge from hospital or transplantation or recovery of the failing heart, as opposed to death before procedural success was achieved.

RESULTS

The data of 358 consecutive patients were analyzed. There were 330 (non)HIT patients (91.6%), 15 HIT(pre) patients (4.5%), and 13 HIT(post) patients (3.9%). Procedural success was observed in 50% of (non)HIT patients, 67% of HIT(pre) patients, and 31% of HIT(post) patients.

CONCLUSIONS

Heparin-induced thrombocytopenia is a frequent complication in VAD patients and is associated with detrimental outcome when occurring after implantation. Preoperative diagnosis of HIT and the implementation of alternative anticoagulation procedures appears to be associated with better results. Early detection of HIT antibodies before or shortly after VAD implantation and immediate implementation of an alternative anticoagulation regimen may be a strategy to improve outcome.

An Intelligent Remote Monitoring System for Artificial Heart

A web-based database system for intelligent remote monitoring of an artificial heart has been developed. It is important for patients with an artificial heart implant to be discharged from the hospital after an appropriate stabilization period for better recovery and quality of life. Reliable continuous remote monitoring systems for these patients with life support devices are gaining practical meaning. The authors have developed a remote monitoring system for this purpose that consists of a portable/desktop monitoring terminal, a database for continuous recording of patient and device status, a web-based data access system with which clinicians can access real-time patient and device status data and past history data, and an intelligent diagnosis algorithm module that noninvasively estimates blood pump output and makes automatic classification of the device status. The system has been tested with data generation emulators installed on remote sites for simulation study, and in two cases of animal experiments conducted at remote facilities. The system showed acceptable functionality and reliability. The intelligence algorithm also showed acceptable practicality in an application to animal experiment data.