Monitoring of a cardiac assist device
A control system for a cardiac assist device includes a sensor implantable in the body at the heart or at an implanted pump of the cardiac assist device, the sensor being for detecting motion of the pump within the body and hence being for monitoring movement of the pump, where the control system is arranged to, in use: receive signals from the sensor, the signals providing information on the movement of the pump; and to process the signals to monitor the pump speed and/or to identify pump malfunction and/or cardiac assist treatment complications.
1 . A method for cardiac assistance of a patient, the method comprising using a control system with a cardiac assist device, the cardiac assist device comprising an implanted pump and an implanted graft, the pump having an impeller for providing blood flow through the pump, and the control system comprising one or more sensors implanted in the body at the heart or at the implanted pump or the graft of the cardiac assist device, wherein at least one of the one or more sensors is a motion sensor, the method including the steps of:
detecting, with the motion sensor, a motion of the pump within the body and thereby monitoring the motion of the pump relative to the body;
receiving signals by the control system from the motion sensor, the signals providing information on the motion of the pump relative to the body;
determining information about pump function, including vibrations caused by the impeller and blood flow patterns through the pump, using the signals from the sensor;
processing the signals received from the motion sensor in order to determine an acceleration signal associated with the cardiac assist device, in order to identify a pump malfunction or to identify complications to cardiac assist treatment;
identifying the pump malfunction or the complication based on the acceleration signal;
determining, based on an analysis of the acceleration signal, when the pump malfunction or the complication occurs; and providing, by the control system, an alert to a user or operator when the pump malfunction or the complication is identified.
2 . A method as claimed in claim 1 , wherein the potential pump malfunction or complication is due to at least one of clotting, embolism, inflow and/or outflow problems, suction, acute Atrial Septal Defect (ASD), and Ventricular Septal Defect (VSD).
3 . A method as claimed in claim 1 , wherein the method comprises changing a flow rate of the cardiac assist device to optimise performance of the cardiac assist device, measuring a corrective effect of the changes in the flow rate of the cardiac assist device and determining that there is a problem when the changes to the flow rate do not result in an expected improvement in heart function.
4 . A method as claimed in claim 1 , wherein the method comprises monitoring of the cardiac pump and/or cardiac function and/or guidance of medical treatment in an acute phase or a follow-up phase.
5 . A method as claimed in claim 1 , wherein the step of processing the signals includes a signal analysis, wherein the signal analysis comprises: a raw signal analysis, frequency analysis, pattern recognition analysis, data streaming analysis and/or acoustic analysis.
6 . A method as claimed in claim 5 , wherein the method comprises identifying, based on the signal analysis, pump parameters that can indicate the pump malfunction or the complication.
7 . A method as claimed in claim 6 , wherein the method comprises identifying, by the control system, the pump malfunction or the complication when the pump parameter(s) derived from the signals differs from an expected or normal pump parameter by more than a given amount.
8 . A method as claimed in claim 5 , wherein the method comprises identifying, based on the signal analysis, changes in the blood flow patterns thorough the cardiac assist device caused by inflow and outflow problems and changes in blood viscosity and embolies caused by air, blood or tissue fragments.
9 . A method as claimed in claim 5 , wherein the method comprises identifying the pump malfunction or the complication due to the presence or absence of one or more predetermined frequencies in the signals.
10 . A method as claimed in claim 5 , wherein the method comprises comparing the signals and/or the signal analysis thereof to historical motion sensor data to identify the pump malfunction and to identify the type of malfunction.
11 . A method as claimed in claim 1 , wherein the method comprises determining if the flow rate is inadequate or excessive, and optimising performance of the cardiac assist device by increasing a flow rate if the flow rate is determined to be inadequate or decreasing the flow rate if the flow rate is determined to be excessive.
12 . A method as claimed in claim 11 , wherein the cardiac assist device comprises a pulsatile pumping characteristic and the optimising comprises adjusting a pulsing speed of the cardiac assist device.
13 . A method as claimed in claim 1 , wherein the method comprises monitoring for a progressive reduction in an afterload of a ventricle of the heart and/or monitoring for an acute increase in the afterload of the ventricle; determining that there is a potentially excessive flow rate when one or both of these occurs; and adjusting the flow rate downwards if it is determined that there is a potentially excessive flow rate.
14 . A method as claimed in claim 1 , wherein the method comprises monitoring for a progressive reduction in contractility and/or monitoring for heart motion indicating a reduced systolic contraction and an increased post systolic contraction; determining that there is a potentially inadequate flow rate when one or both of these occurs; and adjusting the flow rate upwards if it is determined that there is a potentially inadequate flow rate.
15 . A method as claimed in claim 1 , wherein the method includes identifying and monitoring diastolic dysfunction by measuring, using the one or more sensors, early and atrial inflow patterns and relations.
16 . A method as claimed in claim 1 , wherein the method comprises processing signals from the one or more sensors to determine a level of physical activity of the patient and adjusting a flow rate of the cardiac assist device in response to changes in physical activity.
17 . A method as claimed in claim 1 , wherein the method comprises wirelessly transmitting data within the body and/or to outside the body.
18 . A control system for a cardiac assist device comprising an implantable pump, the system including:
one or more sensors implantable in a body of a patient at a heart or at the pump or at an implantable graft of the cardiac assist device, the pump having an impeller for providing blood flow through the pump, wherein at least one of the one or more sensors is a motion sensor, wherein the motion sensor is configured to detect a motion of the pump within the body and thereby to detect the motion of the pump relative to the body;
the control system comprising a processor configured to:
receive signals from the motion sensor, the signals providing information on the motion of the pump relative to the body;
determine information about pump function, including vibrations caused by the impeller and blood flow patterns through the pump, using the signals from the motion sensor;
determine an acceleration signal associated with the cardiac assist device by processing the signals received from the motion sensor, in order to identify a pump malfunction or to identify complications to cardiac assist treatment;
identify the pump malfunction or the complication based on the acceleration signal; and
determine, based on an analysis of the acceleration signal, when the pump malfunction or the complication occurs, wherein the control system is configured to provide an alert to a user or operator when the pump malfunction or the complication is identified.
19 . A cardiac assist device comprising: the control system of claim 18 , the implantable pump and the implantable graft, the pump comprising the impeller for providing blood flow through the pump.