Instrumentation to Record Physiological Parameters During Pre- Clinical Animal Trials of A Prosthetic Heart Valve Device

Authors

Sujesh S, Rajeev A, Muraleedharan CV.

Biomedical Technology Wing (BMT Wing),

Sree Chitra Tirunal Institute for Medical Sciences and Technology (SCTIMST).

Poojapura, Trivandrum – 695012. Kerala, India.

Abstract

Pre-clinical trial is an important test procedure for any implantable medical device. This paper describes the instrumentation test system designed and developed by the Device testing laboratory of SCTIMST to be used during the pre-clinical evaluation on suitable animal models of the improved artificial tilting disc heart valve being developed at SCTIMST. Monitoring and recording physiological parameters such as blood pressure, ECG, and heart valve sounds during an animal model trial are very useful in providing critical data regarding the performance of the prosthetic heart valve. The instrumentation was developed using the LabView software platform and data acquisition and signal conditioning hardware from National Instruments, USA. The system could acquire and record data in real time with good signal strength, and also make it available later for offline processing.

The prosthetic heart valve is a tilting disc device, which consists of three parts – the valve cage, the occluder disc and a sewing ring. The pre-clinical study consists of trials of the mitral prosthetic valve on animal models such as sheep (ovine) and pig (swine). The parameters being monitored include ECG, arterial blood pressure, and heart valve sounds during the implantation of the valve. On successful implantation and survival for a fixed period the heart valve is explanted. During explantation various features of the valve are studied including physiological performance. The parameters studied in an explantation study include ECG, arterial, left atrial and left ventricular pressures, and heart valve sounds. This paper describes an instrumentation setup that includes capability of monitoring upto eight channels simultaneously. Currently five channels have been utilized to measure ECG, arterial pressure, left atrial pressure, left ventricular pressure, and heart valve sound. Additionally a channel was used for recording the signal of a catheter based pressure transducer. The data gained is used to assess the valve performance with regard to its haemodynamics such as transvalvular pressure gradient, level of valve closure sounds and its frequency spectrum, and estimation of parameters such as valve closing time and opening time.

NI Modules used:

1. PXI 1042 Chassis

2. PXI 8186 Controller

3. PXI 6220 DAQ

4. SCXI 1520 Strain gauge module

5. SCXI 1314 Terminal box.