Physiological Control for Mechanical Circulatory Devices

Heinrich Schima7 enrolled

Overview

Aim of this clinical study is to compare our newly developed control algorithms for mechanical circulatory support devices based on physiological demand with the standard manual LVAD speed operation. Specifically it shall be demonstrated that: * Suction is properly detected by the pre-trained pump flow estimation algorithm * Suction events (due to changes in physiological demand) can be reduced by control algorithms compared to continuous speed * If suction is encountered, it can be detected and cleared * The pump reacts adequately to changes in patient demand due to physical activity * Physicians pump setpoints (of requested speed for a certain heartrate) can be achieved safely.

Patients complete a set of tests in constant speed setting and repeat the same tests with physiological control algorithms turned on. Order is randomized.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

DEVICE_FEASIBILITY

Masking

SINGLE

Enrollment

Conditions

Heart Failure

Interventions

Software, which sets the device speed according to physiological demand, is activated for the duration of the tests (up to 4 hours). Every patient provides his/her own control, because sequences with active control and with standard pump operation are subsequently performed in randomized order (determined by permutated blocks).

Eligibility

Sex: ALLMin age: 18 YearsMax age: 80 Years

Medical Language ↔ Plain English

Inclusion Criteria: All patients with a Medtronic HVAD system implanted at the Medical University of Vienna, Division of Cardiac Surgery, which are able and willing to understand and sign the informed consent form, and which do not meet any exclusion criteria will be included. Exclusion Criteria: * Inability to provide informed consent * Patients with known intraventricular or aortic root thrombus formation confirmed by transthoracic ultrasound diagnostic * Known pathology of the coagulatory system * Supra or sub-therapeutic anticoagulation (aPTT or INR) * Suspected or confirmed pump thrombus (based on lab parameters, abnormal high pump power consumption or acoustic spectral analysis) * History of ischemic or hemorrhagic stroke (\<2 months) * Hypertension at rest (mean arterial pressure \> 120mmHg) * Cerebrovascular or musculoskeletal disease preventing the performance of daily life activities or exercise training * Severe arrhythmia (e.g. long QT syndrome), ventricular fibrillation or required defibrillation - excluding the LVAD implantation - in the previous 2 months * All contraindications applicable to the HVAS are applicable to this study. The System is contraindicated: * In patients with a body surface area (BSA) less than 1.2 m² * In patients who cannot tolerate anticoagulation therapy * During pregnancy

Outcomes

Primary Outcomes

Device Feasibility

Feasibility of the Control algorithm to safely adapt pump speed within provided limits, quantified by the number of necessary switchovers to manual mode

Time frame: duration of the testing (up to 4 hours)

Secondary Outcomes

Quantification of overpumping by number of suction events / minute during lying, standing and sitting and comparison with constant speed mode.

Overpumping leads to occlusion of the pump inflow by the ventricular septum and sudden temporary decrease of flow. The number of such events can be counted by analysis of the flow pattern in the pump. The automatic control should lead to a reduction of such events per minute compared to the condition in constant speed.

Time frame: Duration of the testing (up to 4 hours)

Quantification of overpumping by number of suction events / minute due to change of position from lying sitting and sitting to standing compared to the situation in constant speed mode.

Due to decreased venous return at changes of orthostasis the number of suctions increases in constant speed mode. The control should lead to a reduction of suction events due to intermittent reduction of pump speed. The quantification shall be done by comparing the number of suction events/minute immedeately after such changes in controlled and constant speed mode.