Returning a pulse to ECMO

CCRG International Research Fellow, Dhayananth Kanagarajan has led a new study aimed at developing a model of venoarterial (VA) ECMO in a patient-specific human aorta to evaluate the effect of ECMO timings and pulsatility. The study, which formed the basis of Dhayananth’s PhD, is one of the most advanced and most clinically relevant in this area and aims to support the continued development of ECMO technologies.

“As an engineer, ensuring the computational modelling was as relevant for both preclinical and clinical settings was the most challenging part of the study,” explains Dhayananth.

“It was always my intention to ensure the research was as relevant as possible to enable rapid translation and further industry engage, so being able to do this work at CCRG, with its clinical ties was a significant advantage. Being able to have regular discussions with clinical SMOs including Dr Silver Heinsar and Professor John Fraser was crucial to overcoming this challenge.”

“The study revealed a trade-off between cardiac unloading and hemodynamic energy transmission when altering ECMO pulse timings. This finding demonstrates that proper timing of pulsatile flow delivery during a cardiac cycle is crucial to maximize benefits and can be tailored to specific heart disease condition.”

There are very few researchers worldwide working on pulsatile flow ECMO, and those that are primarily conduct bench-top mock loop experiments or preclinical studies, not both.

Although preclinical studies have shown benefits of pulsatile flow relative to continuous ECMO flow, none have explored the effects of the timing of ECMO pulses with respect to the cardiac cycle and its possible implications on ECMO complications.

“Previous studies have not consistently demonstrated the benefits of pulsatile flow, partly because ECMO pulses were typically delivered during either the ventricular contraction or relaxation phases.

“Whilst the current ECMO systems allow to delay pulse delivery, we have no idea what the optimal delay is nor how to recognise it in clinical settings. Our study not only found an optimal pulse delay, but also provides suggestions on how the arterial waveform looks if we reach this condition” said Dhayananth.

It is hoped that the findings from the study can help ECMO manufacturers improve device capabilities by incorporating ECMO pulse delay settings, pathing the way for more effective preclinical and clinical studies and ultimately, improved outcomes.

Doug Vincent, President and CEO of VentriFlo Inc, said the study was is another example of CCRG’s ground breaking work, multidiscipenary research that is working towards brighter futures for patients.

“As we continue to investigate and develop novel pulsatile blood pumping systems, we look to world leaders like CCRG who are driving innovation in this area. By harnessing the power of collaboration with CCRG and the expertise of their labs, we hope to be able to achieve superior outcomes, reduce costs and improve safety for patients who require cardiopulmonary support during surgery or in the ICU.”

CCRG International Research Fellow and study consultant Dr Silver Heinser said that study is of vital importance to the field of pulsatile ECMO, because it builds on the theoretical basis that pulsatile ECMO works with numbers.

“Dhayananth’s incredible study provides mathematical evidence of the effects on unloading and hemodynamic energy transfer (which suggests microcirulatory benefits). It teaches us as clinicians and as industry how to set up the pulsatile machine so that we receive maximal benefits and gives us simple tools to recognise if the patient is getting this benefit or not.

“This study embodies Professor Fraser’s vision of how we can make meaningful impact when we break through professional barriers and do interdisciplinary research. It’s been a great fun to dive into the engineering world with Dhayananth on this one,” said Dr Heinsar.

The research continues with further evaluation of timing in a flexible aorta using fluid-structure interaction study, as the current study modelled the aorta as a rigid blood vessel due to model complexity.

“It’s a complex but exciting threshold to be approaching as we look to further our understanding of pulsatile VA ECMO and associated technological advancements,” said Dhayananth.

In Silico Analysis of Pulsatile Flow Veno-Arterial Extracorporeal Membrane Oxygenation on Human Aorta Model

Electrocardiogram (ECG)-synchronized pulsatile veno-arterial extracorporeal membrane oxygenation (V-A ECMO) is a recent development in extracorporeal therapy for patients with severe cardiogenic shock. Continue reading.