Continuous Out-of-hospital Monitoring of Rotary Blood Pump Patients

Rotary blood pumps (RBPs) are increasingly used as ventricular assist devices to treat patients with terminal heart failure until heart transplantation, as destination therapy (for lifetime), or until recovery of the failing heart. Due to the increasing numbers of implantations and improved patient survival, long term out-of-hospital management of RBP patients requiring continuous diagnostics is a challenge for the immediate future. Conventional diagnostic workups including cardiac ultrasound, catheterization and/or spiroergometry are difficult to apply continuously because they involve cumbersome and cost-intensive invasive and noninvasive procedures. An overall optimization of hospital resources as well as the improvement of out-of-hospital care seems mandatory at this stage. A continuous outpatient monitoring, especially aiming at an early recognition of complications, could represent a useful tool for such optimization of resources and care. Our group has developed several algorithms suitable for monitoring of the cardiovascular function (ventricular contractility, relaxation, aortic valve condition, heart rate and its variability, arrhythmia). These methods are all based on the analysis of pump data (current and speed), which can be noninvasively and continuously recorded from the RBP itself. In this project, the accuracy and reliability of the pump-based continuous monitoring methods will be evaluated in an open observational prospective study involving 30 RBP patients. Our aim is to find relationships and agreements between pump-based monitoring and standard clinical diagnostics as well as to collect and analyze long-term diagnostic data from RBP patients. Our key hypothesis is that pump-based methods can trustworthy complement standard in-hospital diagnostic methods and thus allow an improved the long-term out-of-hospital clinical treatment of RBP patients. Pump-based monitoring will be continuously performed for one year after implantation in combination to cardiac ultrasound, Holter-ECG, and physical performance tests such as 6-minute-walk-test and spiroergometry. A comprehensive noninvasive evaluation of cardiovascular function derived from analysis of pump signals will enhance clinical practice and RBP patient treatment. The continuous patient monitoring can lead to a better long- term preservation of the assisted cardiac function and to early recognition of complications, while at the same time reducing the diagnostic burden for out-of-hospital care of patients. It is obvious that this will head to an increase of life expectancy, quality of life and eventually an increase in the observed cardiac recovery rates.

For patients with terminal heart failure miniaturized implantable rotary blood plumps (RBP) normalize hemodynamics by supporting the function of the failing heart. Monitoring of patients is currently limited to routine ambulatory visits or hospital readmissions without access to outpatients. Within this study methods to continuously (24/7) monitor RBP outpatients were developed and validated against clinical diagnostics. The developed methods evaluate hemodynamics (by detecting cardiac ejection through the aortic valve), seek to anticipate adverse events (as pump-thrombosis or ventricular collapse due to overpumping), and provide insight on the remaining exercise capacity of patients, particularly on the current limitation of RBP output to support maximum capacity testing. In addition a telephone clinical intervention algorithm for outpatients was developed within this study that resulted in significant improvements of patient survival after 2-years, thus setting the basis for larger scale implementation of tele-monitoring. In aggregate the project results indicate that the continuous patient remote monitoring can be of great value for an improvement of care.