Frugal innovation in cardiac surgery

Abstract

The development of a tilting disc heart valve in full compliance with ISO standards and affordable for low-income patients in India was undertaken in the early 1980s at the Sree Chitra Institute, Trivandrum. The constraint on resources and emphasis on self-reliance made frugal innovation obligatory for valve development. After the failure of three initial models, the fourth model succeeded and was used clinically in December 1990. Equally successful in a multi-centric trial in India, it has been implanted in over 100,000 patients to date. In overcoming problems in relation to the choice of materials and tests for performance during valve development, several innovations were employed in the low-resource setting of Chitra Institute, which anticipated the advent of “Frugal Innovation” by three decades.

Frugal innovation: a global phenomenon

In 2012, Radjou and Prabhu published a best seller with the intriguing title Jugaad Innovation based on considerable research [1]. They borrowed the word “Jugaad” from Hindi, which means an improvised solution arising from native ingenuity and skill. “Jugaad” had been practiced for centuries in developing countries such as India, Brazil, and Kenya to solve day-to-day problems at work and at home. Jugaad innovation sought to produce solutions which were not only effective but were also affordable for the common man. This idea gained currency in the west when Renault—a French car manufacturer—built a car in the 1990s in Romania whose economy had withered under communist rule. The car built in Romania—Logan—differed from its counterpart built in France because it employed French designers and Romanian manufacturing engineers in its development. Logan combined the high end design sensitivity of the French and the cost sensitivity of the Romanian partners in the R&D team. Priced at 5000 euros, the car was a run-away success in not only low-income countries but also in the rich world. The joint effort of the French–Romanian team achieved “more with less,” which became the mantra of frugal innovation (FI) and earned the sobriquet “frugal engineering” (Ghosn) [2]. The term signified the ability for quick and effective innovation at low cost in the face of constrained resources. Frugality which was the hall mark of life in developing countries drew the attention of the rich world toward the end of twentieth century due to the pressure of circumstances.

FI in health care

The influence of FI on the corporate world has been enormous as evident from the 50 case studies reported by Radjou and Prabhu. Modern health care is sustained by a large industry even when pharmaceutical companies are excluded from the list. In terms of the essentiality of patient services for public good, products of health care industries have a social value which greatly exceeds their commercial value. The rising cost of health care is a major concern in rich and poor countries, and a major share of the cost is claimed by medical devices which include equipment like magnetic resonance imaging (MRI), disposables, implants, and minor instruments [3]. India is among the top 20 markets for medical devices in the world, which accounted for Rs. 13,000 crores in 2009–10, of which almost 70% was imported and the import grew at 10% per year. Today, it is estimated to be Rs. 25,000 to 30,000 crores but the percentage of imports remains unchanged. Domestic production is limited to the low-tech segment of disposables; high end equipment and even their parts and accessories are imported. Household survey data show that the vast majority of Indians do not have access to medical devices while private sector hospitals are using medical devices in a big way [4]. It is a sobering thought that India depends on imports for meeting 70% of its requirements for high-tech devices used extensively in the treatment of non-communicable diseases. As a consequence, these devices are available and accessible only to high-income groups who may constitute no more than 20% of the population. The polarization between 20% who have and 80% who have not is a recipe for social disharmony which is detrimental to national development. It is essential that medical devices which constitute a large segment of health care are designed and produced in India on a massive scale to expand their access and affordability. This would be impossible if we adopt the erstwhile practices in the west of making over-engineered and sophisticated products which would claim, rightly or wrongly, superiority over their competitors. To meet the demand for medical devices from a reformed health care system accessible to 80% of India’s population, a different approach to R&D, product development, and manufacture with heavy emphasis on FI would be mandatory. What did however escape the attention of technologists and management experts in India is the outstanding example of the TTK-Chitra valve—a class III high-risk device—which was developed entirely in India and had anticipated FI during its development in the 1980s.

TTK-Chitra valve

When Sree Chitra Tirunal Medical Center (Chitra hereafter), a Kerala Government institution for cardiac and neurologic diseases, opened its door to patients in 1976, open-heart surgery was not practiced in the state. As the Medical Center offered services free of cost for poor patients, the hospital soon attracted large numbers of patients with valvular heart disease who desperately needed valve replacement. The Government grant was too little to buy imported valves to meet escalating demand, and “waiting list” of patients became a sickening reality. This was the predicament which made a tiny group of a cardiac surgeon, a biomedical engineer, and a veterinary surgeon to toy with the idea “why not make a valve here” [5]. It was greeted with disbelief verging on derision, but the die had been cast and there would be no going back. We laid down two inviolable conditions for valve development, and these were in compliance with ISO standards and affordability of the valve for Indian patients. Our effort claimed the better part of the 1980s and attracted two more engineers as years passed. We opted for a tilting disc model for valid reasons, and the first model featured a valve housing made of titanium, disc fabricated of polyacetal (Delrin), and a sewing ring of polyester fabric [6]. As Chitra had limited facilities but plenty of friends, electron beam welding of the struts in valve housing was done for us by the Pressure Transducer Fabrication Facility (PTFF) of ISRO, Bangalore, and knitting of polyester yarn for the sewing ring by South India Textile Research Association (SITRA), Coimbatore. Since polyacetal was cheap, DuPont sent us a free supply of 20 kg in response to our request for a pro forma invoice! Unfortunately, this model failed during performance tests [7]. This setback was dwarfed by the failure of the second and third models as well. The failed models are listed in Table 1 and illustrated in Figs. 1, 2, and 3 which indicate the reasons for the failure during tests [8].

Table 1.

Chitra valve models

Valve model	Housing material	Disc material
Model I	Titanium	Delrin—500
Model II	Titanium	Sapphire
Model III	TiN-coated Haynes 25	Sapphire
Model IV	Haynes 25	UHMW-PE

Fig. 1.

Titanium—Delrin model

Fig. 2.

Titanium—Sapphire model

Fig. 3.

Haynes 25—Sapphire model

It is interesting how the Chitra group with inadequate resources overcame the failures by planned networking with other institutions in India as it would have been impossible for the institution to set up laboratories in-house and hire skilled technologists to solve varied problems during valve development. When model 1 (Fig. 1) failed, the weld fracture was analyzed by National Aerospace Laboratory (NAL), Bangalore, who found that weld embrittlement had occurred due to the presence of traces of oxygen in the welding chamber. We decided forthwith to avoid the use of welded components in blood stream. This led to the development of an integral housing of titanium in model 2 (Fig. 2), which however failed because of a mismatch between the housing and disc. In this model, housing of titanium had become integral but single crystal sapphire had replaced polyacetal of the disc in view of the water absorbing property of polyacetal during autoclaving. In the wear tester, it was noticed that the integral struts of titanium would wear rapidly against tilting by the harder disc of sapphire. The wear was so severe that the disc tended to escape from the valve assembly! Like true descendants of Bhageeratha, we pushed on and made model 3 (Fig. 3) which featured Haynes 25 as housing material—a chromium cobalt alloy harder than titanium—with a totally inert titanium nitride coating—and sapphire disc. The failures of two models and heroic efforts at correction had already claimed 5 years, and we were often reminded of the numerous valve models which failed to survive the developmental phase and found a resting place on the shelves of the Baxter Museum in the USA! At this critical stage, when model 3 had gone through all the tests flawlessly and was functioning well in the mitral position in sheep, one animal dropped dead suddenly thanks to the fracture of the sapphire disc in the valve. There were sheep with the same valve in the mitral position running about at that moment. Shaken but undaunted, Chitra group came up with model 4 (Fig. 4) in less than 6 months with a housing of Haynes 25 without titanium nitride (T₁N) coating, disc of ultra-high molecular weight polyethylene (UHMWPE) and sewing ring of knitted polyester cloth [9]. The series of three adversities catapulted the team to a highly successful model 4 which passed every test prescribed by ISO and performed very well in sheep. The choice of a UHMWPE for fabricating the disc was fortuitous; it received a US patent and was shown to be superior to discs made from hard materials such as sapphire in performance. Following approval by Institutional Ethics Committee (IEC), the valve was implanted in the aortic position in a patient on December 6, 1990, at the Chitra Institute, Trivandrum. The patient did well and continues to remain well and active today. The valve was shown to match an imported valve of similar design in a multi-centric trial [10]. It has been implanted in 100,000 patients in many hospitals across India up to now and has amply fulfilled the objectives of the Chitra group who insisted on the valve’s compliance with ISO standards and affordability for Indian patients. Moreover, TTK-Chitra valve has dramatically pushed down the price of an imported valve by 50% of its pre-Chitra valve price! The current model 4 is a triumph not only for FI in cardiac surgery but also for tens of thousands of patients (Table 2).

Fig. 4.

Current model

Table 2.

TTK-CHITRA valve: prices game

1990 (all imports)	TTK-Chitra enters in market	1995
Ball—Rs. 22,000 Single disc—Rs. 33,000 Bileaflet—Rs. 45,000		TTK.Ch.—Rs. 15,000 Bileaflet—Rs. 35,000
	2017
TTK.Ch.—Rs. 25,000 Bileaflet—Rs. 25,000 (only in India, internationally US$ 2000–3000) Lower price of imported valves in India is solely due to effective competition by a low-cost, high-quality indigenous valve—achievement of FI

Resonance of FI in TTK-Chitra heart valve

The development of TTK-Chitra valve was conceptualized in response to the high cost of imported valves and their unaffordability for the majority of patients who were seriously ill. The aim of the valve project was not to develop a highly profitable product to compete with imported valves but to make a prosthetic valve which would fully comply with ISO standards and remain affordable to Indian patients. As far as we know, the inclusion of this sociological requirement in the development of a class III device was unique in the history of valve development.

The lack of advanced research facilities in biomedical engineering and constraint on financial resources obliged Chitra to innovate, to use existing machines for unprecedented applications, to make instruments matching in excellence with prohibitively expensive imports, and to use available resources in India—human and material—to the maximum advantage.

Valve housing

The fracture of the welded strut (model 1) made it clear that the use of welded components in a cardiovascular implant carried unacceptable risk and an integral housing was mandatory for the valve. This would require in the early 1980s, a computer numerical control (CNC) machine which was hugely expensive and inaccessible for the Chitra Institute. Employing innovative methods, two major struts (graphite) and one minor strut (copper alloy) were made by using copy milling techniques on a low-cost, pantograph milling machine^# available in the Chitra tool room. Graphite was used to make the tool for major struts only because copper alloy became temporarily unavailable from the supplier! (Figs. 5 and 6). These tools were used to machine an all integral housing in an electric discharge machine (EDM)^## developed in India and easily available. The housing was hand finished and polished using low-cost methods. This innovative approach of making an integral housing made it possible to advance the valve project throughout the developmental phase. CNC machine entered the scene only when the valve was produced commercially in the late 1990s.

Fig. 5.

Valve housing: graphite tool for major struts, copper tool for minor strut, and blank

Fig. 6.

Valve housing: housing sitting snugly in the tool and machined Housing

Disc

The present UHMWPE disc in model 4 is the third in the series of discs used during valve development. Polyacetal (Delrin) in model 1 was given up because of its water-absorbing property; the next, a sapphire disc, had to be dropped thanks to excessive wear of struts of the titanium housing of model 2 and fracture of the sapphire disc in model 3 featuring a Haynes 25 housing. UHMWPE disc was chosen in a crisis situation from among five candidate polymers suggested by National Chemical Laboratory, Pune. Apart from standard tests for toxicity and mechanical properties, the wear of the material had to be determined as it was critical. As the Chitra group was under great pressure, the tests for adhesive and abrasive wear had to be determined quickly through sub-system testing instead of testing a fully assembled valve. Accordingly, two test equipments for testing adhesive and abrasive wear were designed and made in-house since they were not available for purchase off the shelf (Figs. 7 and 8). This was innovative and affordable in contrast in getting them made on order at high cost.

Fig. 7.

Pin-on-wheel schematic—1

Fig. 8.

Sand-slurry test schematic—2

According to ISO standards, the durability of the valve for 10 years had to be demonstrated by in vitro tests. These are demanding because the valve opens and closes 100,000 times a day, and the durability tests for 10 years would demand 365 million cycles of disc motion in a wear tester without malfunction. In the accelerated wear tester built in Chitra, the valve cycles were fixed at 800 times per minute so that the durability of 10 years could be demonstrated in 1 year (Fig. 9).

Fig. 9.

Accelerated durability testing

Compression molding of UHMWPE resin powder for discs was difficult due to the tendency for inclusion of voids and flaws while the imported machine for isostatic compression was too costly. This problem was addressed by developing an innovative method of making discs from high-quality extruded rods of UHMWPE with a standard lathe and subjecting them to high compression in highly polished molds, heated to a softening temperature, in an ordinary rubber compression molding machine.

However, the highly polished discs had a problem of having micro-irregularities at the edges which made the exact control of diameter difficult. Innovation came to the rescue again. A cryo-machining system was set up where the molded discs were cooled at − 15 °C and edges trimmed accurately to the exact diameter desired. (This received a US patent.)

Sewing ring

The polyester yarn for making a sewing ring had been chosen by the Chitra group on the basis of in vitro and in vivo studies [ref. 6], and its knitting and fabrication were done by SITRA. The ring not only enables the surgeon to stitch the valve in position, its interface with cardiac tissue becomes important as the point where thrombus originates. Its biocompatibility, thickness, and geometry are exceedingly important. The fact that throughout the changes in experimental valve models, the sewing ring remained unchanged bears testimony to its excellence. When the production of the valve was scaled up, the skilled job of hand fabricating the sewing ring from plastic fabric was handed over to Daya Industry, a small scale industry under the Womens’ Industry Programme located near Trivandrum, giving employment to women in the area. The fitting of the ring on valve housing is also a skilled operation.

Performance tests

While wear tests mentioned earlier relate to durability, the opening and closing functions of the valve are tested in a pulse duplicator which is essentially a simulator of the left ventricle of the heart with inflow (mitral) and outflow (aortic) valves. The electronic controls and data recording system permit the rate, volume of flow, upstream and downstream pressures, leaks on valve closure, and flow velocity to be measured and recorded. Pulse duplicator is unavailable off the shelf and had to be made on order, which made it highly expensive. An excellent pulse duplicator was made through FI at a fraction of the cost of an imported system at Chitra (Fig. 10). For measuring flow velocity in the pulse duplicator, a Laser Doppler Anemometry (LDA) is used abroad which cost Rs. 1 crore in the 1980s. The same measurement was done by a “Pulse Ultrasound Doppler Velocimeter” (PUDVEL) designed and built by the Chitra group at a cost of Rs. 10 lakhs.

Fig. 10.

Hemodynamic tests: steady flow testing and pulse duplicator

Technoprove

It is common for higher educational institutions to display an array of medical devices and instruments developed by students and faculty, which however are not produced commercially or used by hospitals or patients. A major reason for this paradox is that the devices and instruments had never been subjected in multi-centric trials to replicate the original results. Aware of this pitfall and mindful of Good Manufacturing Practice (GMP) conditions, Chitra built a facility in the 1980s—Technoprove—where medical devices such as blood bag, oxygenator, and heart valve could be made in hundreds by technicians deputed by industry under the watchful eye of the engineers who developed them (Fig. 11). The products of Technoprove would be used by a few reputed institutions in India on a common protocol, each institution having facilities for conducting the trial by competent physicians with IEC’s approval. This was a condition imposed by Chitra for any high-tech device to be dignified as “technology.” In the absence credible multi-centric trials, the benefits of FI in the development of high-tech medical devices would fail to reach long-suffering patients.

Fig. 11.

Technoprove

Conclusion

The “rustless steel” made in ancient India was famous all over the world. Keenly interested to learn how the steel was made by the “natives,” British East India Company deputed an engineer Major James Franklin FRS from Calcutta to study “Indian mode of manufacturing iron.” He described in great detail the raw materials, ore, and charcoal, for making iron; construction of a smelting furnace “rude in appearance but very exact in its interior proportions; men unquestionably ignorant of principles, but construct them (furnaces) with precision, in so simple a manner;” construction of refineries to decarbonize the smelted iron; and how the final product was certified glowingly by Col Presgrave of the Sagar Mint as “of the most excellent quality, possessing all the desirable qualities of malleability, ductility at different temperatures and of tenacity for all of which I think it cannot be surpassed by the best Swedish iron [11].” For the unlettered men who toiled at the furnace in Central India, Jugaad innovation was their patrimony and the way to make their humble living. The TTK-Chitra valve, a symbol of FI in the twentieth century, speaks loudly that the spirit of innovation which drove the workmen in Franklin’s report is alive in India. Moreover those few who took part in the Chitra valve odyssey have a proud lineage reaching back to the men who made rustless steel in ancient India.

Compliance with ethical standards

Informed consent

This paper does not require informed consent, according to “Journals” guidelines. The clinical trial mentioned in the paper was done in 1992 at the Chitra Institute, Trivandrum, and had taken the permission of the IEC of the Institute. The original paper on clinical trial was published in Journal of Heart Valve Diseases cited in the present paper. I repeat the present paper does not require informed consent or approval of IEC.

Conflict of interest

The author declares that there is no conflict of interest.

Ethical approval

For this type of long-term review, approval from Institutional Ethical Committee is not required.

All procedures performed in studies involving animals were in accordance with the ethical standards of the Sree Chitra Tirunal Institute at the time of the studies.