Multiple blocks. Artificial heart: More than rocket science

Our hearts race excitedly, hearing that an artificial heart will be made in India. The famed Indian Institute of Technology Kanpur will ready an artificial heart for clinical trials in the next two years. So many questions race through our mind —; when can we have it, in three years? How many companies will make this product? Is this technology recent? And many more.

The artificial heart has an interesting Indian connection. The Nobel prize-winning physiologist, Ronald Ross, while working in India, wrote a sci-fiction book based on an artificial heart contraption. Exactly a century later, his device was realised and implanted into a retired dentist in Utah.

The artificial heart has a long history. In 1963, after several attempts by various researchers for over half a century, Michael DeBakey, considered the father of artificial hearts, put forward a plan to the US government to build an artificial heart.

That was the beginning of the Kennedy era that kindled the American scientific spirit with the President declaring that “(we do) things not because they are easy, but because they are hard”. DeBakey was allocated $40 million (about $250 million in today’s prices) to produce an artificial heart by 1970.

Left Ventricular Assist device

Six decades have passed, and humanity is yet to conquer the heart. An ideal artificial heart is still elusive. Left Ventricular Assist Device (LVAD) that supports the left ventricle to pump blood is monopolised by one device, HeartMate III. A recent trial showed that 77 per cent of the patients were still alive after two years, and the device had “low disabling stroke rate” whatever that sentence means.

There has been non-stop development over the past six decades, and we are in the late stage of the third-generation LVADs. Pumps that mimic the heart, called pulsatile pumps, have come and gone.

Pulseless devices that send blood continuously are tethering with adverse events; strokes, gastrointestinal bleeding, device malfunction and driveline infection. Though there have been a reduction in some of the adverse events, readmission rates are still high, at 72.2 per cent within one year. At this stage, Indian engineers are entering the scene; 60 years of development and one LVAD monopolises the market. Not that the market is a crippler — it is a billion-dollar-plus industry. The heart is an engineer’s delight and a clinician’s nightmare. Cardiac mechanics is right out of the alley of an engineer. An artificial heart is a nightmare for both fraternities.

In the first instance, it looks like a pump that can be designed as an assignment in a turbo-machinery class. After all, German engineer Cordier codified the pumps decades ago. But there should be reasons for the 60-year struggle with the artificial heart. For example, in a biological circulatory system, shear stress, which decides well-being, is 1 to 10 Pascal. Pumps have a value higher than 250Pa.

The reasons for the high incidence of stroke are still not clear. It may be due to implantation techniques, including the inflow graft, biological changes due to the pumps, or thromboembolic complications (blood clots that break loose) in pumps. With these patients under anticoagulant therapy, gastrointestinal bleeding is another Achilles Heel.

Driveline infections should make engineers think of novel ways to deliver energy effectively. These problems require efforts from an interdisciplinary team consisting of engineers of varying backgrounds, biologists and clinicians.

Reality check

With this background, Indian engineers require a reality check. Artificial heart development requires time. With no high-tech institute having medical and engineering streams under one roof, the nuances of collaboration of two disjointed groups, the engineer and the clinician, are just being learnt.

First and foremost, medical devices require a scientific and unbiased regulatory process for approval. Board-to-bench-to-animal-to-bedside is based on well-defined protocols that do not exist in this country and makes it more challenging than drug approvals. Products also require electromagnetic and electrical compliance, biocompatibility, etc.

The science of LVAD design is just emerging. When shifted from the bridge-to-transplant to the destination therapy, the long-term effects of pulseless existence need to be understood. The design must be fault tolerant, making reliability not a virtue but a hygiene requirement.

Today, Philips, the biomedical giant, is facing a crisis, with its shares moving rapidly south due to a massive recall of some of its respiratory products. Medtronic recently recalled its LVAD and does not have a product in this space. These products require utmost care, excellent processes, and extensive testing. Animal laboratories are essential for their success, and this country of 1.2 billion has barely a handful of approved animal facilities.

News about biomedical products gives hope to millions. There needs to be staging in its announcement, starting with scientific conferences, peer-reviewed journal publications, regulatory bodies and clinical trials and ultimately to the common public. In 2009, IIT Kharagpur announced the development of an artificial heart to be sold for ₹1 lakh. Several such proclamations from various research organisations have come but never materialised into a product.

Indian engineers and scientists are a talented lot with many success stories under their belt. But challenging problems require an understanding of the minefield.

America announced the “man on the moon” project along with the artificial heart, and within a decade, Neil Armstrong made that famous statement from the moon. Heart is still waiting to be conquered. Indeed, the artificial heart is much more than rocket science.

The writer, Institute Professor, IIT Madras, works in the area of cardiac mechanics and device development

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