From aircraft aerodynamics to improved heart implants

Genoa 27 September 2005At first glance airplane wings and human hearts have little in common, but, say a team of European researchers, a technology used to measure airflow over wings can now be used to help keep hearts in working order. The researchers from Italy, Germany and Greece have optimised a Particle Image Velocimetry (PIV) system of the kind traditionally used to improve the aerodynamics of aircraft wings to make it capable of accurately measuring the effects of medical implants on blood flow. On the one hand their work will allow medical device manufacturers to improve the design of devices such as heart valves and pumps, while on the other it will provide doctors with a way to detect - and ultimately correct - the side-effects that commonly afflict patients who receive implants.

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"This system is likely to have a significant impact on the heart device market over the coming years. In fact, it could revolutionise heart treatments", stated Fabrizio Lagasco, the co-ordinator of the IST programme-funded SMART-PIV project. The SMART-PIV system - which combines the optimised PIV hardware with advanced image processing and numerical analysis software over a parallel computing subsystem - fills a gap in the heart device sector that has limited the efficiency of implants.

Though ultrasound scans allow doctors to view potential problems with the natural heart, as well as locally in the circulatory system, they fall short of providing a detailed analysis of the causes of problems related to blood flow when modified by artificial implanted devices. In the field of biomedical device design, experiments involving the implantation of medical devices into animals can prove that a device functions, but such in vivo trials are lengthy and costly as well as not always being indicative of the effects the implant will have in humans. "A cow heart is different to a human heart", Fabrizio Lagasco noted. "That can lead to unforeseen complications."

Complications, ranging from the minor to the potentially fatal, are widespread among patients who receive implants either as a long-term solution to a failing heart or as a temporary "bridge" while they await a transplant. Heart valves, which are implanted into around 225.000 people worldwide each year and can prolong their lives for decades, lead to many patients requiring anticoagulant drugs to prevent clotting and thrombosis, which in turn raise their risk of severe bleeding. Stents, which are used to prop open blocked arteries, pose similar problems and can lead to infections.

Though such implants play a vital role in prolonging the lives of people with cardiovascular disease, reducing their side-effects through improved in vitro design would undoubtedly increase patients' quality of life and their chances of long-term survival. That is particularly true in the case of ventricular-assist devices (VADs), battery-operated pumps that support a failing left ventricle and help supply blood to the rest of the body. VADs are primarily used to buy patients time until a heart donor can be found, but even in a best case scenario they can currently only extend a patient's life by up to two years and frequently just a few months.

By applying PIV technology in their development Fabrizio Lagasco expects it would be possible to greatly enhance their performance and grant patients more time to obtain a transplant. "With so few donors available compared to the people who need new hearts the number of people with implants is only going to continue increasing", the project co-ordinator noted. Indeed, cardiovascular disease is the principal cause of death in Europe, claiming around four million lives a year. "That is why we saw the need for this technology to be applied in the medical sector", Fabrizio Lagasco stated.

At the core of the project's PIV system is miniaturised optical sensor technology using ultra-thin laser light sheets to capture images of the fluid dynamics of blood flowing through implanted devices. Numerical analysis is carried out on the images in a parallel computing subsystem allowing device designers or doctors to detect problems with the blood flow, such as high velocity gradients that can cause blood cell damage, or low velocity that could lead to thrombosis or coagulation.

Based on the results of trials carried out by the SMART-PIV partners, by employing parallel computing the analysis can be performed in under a day in 80 percent of cases and in less than two days in all cases. "As computer processing power increases we estimate that within two years the analysis could probably be performed in two to three hours", the project co-ordinator stated. "That compares with the weeks or months it can take to obtain results from using traditional PIV systems."

An easy-to-use Graphical User Interface ensures the system can be used by doctors and others who are not necessarily experts in PIV technology. Having tested the system in vitro during the project, the SMART-PIV partners are currently planning to develop and evaluate it further in trials involving a medical device manufacturer.

"We're currently in talks with Sorin, a multinational producer of heart valves, and with an Italian SME that is looking to use SMART-PIV to optimise the design of their VADs", Fabrizio Lagasco stated. "The commercial possibilities for the system are therefore extensive and a product based on the project results will probably be in use within the next few years."

In addition, secondary scouting activities will be also launched to investigate the market opportunities in alternative fields, like defence and shipbuilding, taking advantage of the project co-ordinator's position as specialist consultant in relevant industrial companies nationally and internationally.

For more information you can contact Fabrizio Lagasco at D'Appolonia S.p.A., Via San Nazaro 19, I-16145 Genoa, Italy, Tel.: +39-010-3628148, Fax: +39-010-3621078 or visit the SMART-PIV project Web site. This article was reprinted from the IST Results Web site.


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