A man in Hyderabad, India, now joins a short list of lucky individuals who are alive and well thanks to two independently beating hearts. The 56-year-old patient was near death from advanced heart disease when a compatible donor heart from a brain-dead 17-year-old suddenly became available some 150 kilometers (93 miles) away. After rushing to get the donor heart to Apollo Hospital within the 4-hour viability window, the waiting physicians were temporarily flummoxed when they discovered it was far too small to pump blood through the patient’s larger body. “The donor heart was of normal fist-size. The recipient’s heart was the size of a small football,” said cardiothoracic surgeon Dr A. Gopala Krishna Gokhale to The Hindu. Thinking on their feet, Dr Gokhale and his fellow surgeons pulled off a procedure known as heterotopic or “piggyback” transplantation, attaching the new heart to the patient’s existing heart to support its remaining function rather than replace it. During this type of implantation, the new heart is placed in the chest cavity to the right of the existing heart, and the two left atria – the chambers that receive freshly oxygenated blood from the lungs – are fused to form one larger chamber. The new heart’s aorta – the large artery exiting the heart that branches into the rest of the body’s smaller blood-supplying arteries – is then attached to the existing aorta, allowing muscle contractions from both hearts to push blood throughout the circulatory system. Next, the new heart’s pulmonary artery is sutured to the old heart’s right atrium so that it may help perform the work required to transport returning, low-oxygen blood from the coronary sinus to the lungs. Developed and first performed by famed South African cardiac surgeon Christaan Barnard in 1974, later versions of the procedure usually include connecting the two hearts’ right atria as well. According to Dr Gokhale, piggyback transplantation has only been performed about 150 times worldwide. What we think of as standard heart transplantation, called orthotopic and also pioneered by Dr Barnard, has been performed many thousands of times and lasts for an average of 10 years. Some studies have suggested that heterotopic transplants can last as long, but since so few have been done, it's hard to say definitively. A diagram of steps involved in the heterotopic heart transplantation procedure. Abicht et al./Xenotransplantation, 2015 Before drugs that prevent the body from rejecting a transplanted organ were invented the two techniques seemed to have similar success rates. Heterotopic even appeared to have an edge over orthotopic because differently sized hearts could be used. But after cyclosporin immunosuppressant medicines greatly improved orthotopic survival rates, heterotopic transplantation was relegated to special cases of high blood pressure in the lungs or extreme size mismatch only. The Indian patient, one of such special cases, is reportedly doing well since the operation. “It is once-in-a-lifetime procedure a doctor performs. Patient’s blood pressures are close to normal and he is stable,” said Dr Gokhale. Although he is no longer stuck in mortal limbo on a transplant waiting list, life will never quite return to normal either. He will need the same intense regimen of care that all heart recipients require, yet his doctors must monitor two distinct heartbeats and electrocardiogram readings. Caution graphic content: The video below demonstrates a heterotopic procedure. Source
