What are heart Valves
Heart Valves separate the four chambers of heart that collect and pump blood. They control the direction of originated and unoxigenated blood flow for proper functioning of heart. Heart valves are marvels of natural engineering as they last a life time, even for few hours after death.
Sometimes valves get diseased and do not work right. They might not open all the way leading to reduced flow of blood or they might have problem closing leading to leakage of blood backwards. Due to these problems the heart will have to work harder to pump the same amount of blood and the blood may back up in the lungs. Therefore valve repair or replacement is required.
Heart valves get damaged in various diseases either because of age, infection or failure of previous heart valves operations. Sometimes, as the problem exists by birth, the valve need replacement even for newborns.
Rheumatic heart Diseases (RHD) is one of the key reasons for valve related problems. Many researches have established that the countries with low socio economic groups like India are more susceptible to RHD due to conditions like poor hygiene, lack of medical facilities, poverty, illiteracy and fear of drugs.
Need of Valve Transplantation
Every year, more than 1 lac heart valve procedure are being done worldwide and the number is expected to go as much as 8 lakh by 2050.
If valve is to be replaced then there are options of mechanical or biological transplants. The biological valves obtained from human beings through cadaveric donation, called homograft, are closest to the ideal valve as they are silent, last longer, do not require anti-coagulation and are comparatively free of complication.
Out of the four valves in heart 95% of valve replacements are performed for mitral or aortic valves.
Cadaveric Valve Donation
In case of a cadaveric donor, heart valves are tissues that can be harvested even from the patients whose complete heart is not suitable for transplantation. Heart valves must be recovered within 15 hrs
if the body is not refrigerated of within 24 hrs if the body is refrigerated within 12 hours of death. Most important is that even if transplant surgeons are not available at the centre where death occurs, even a general surgeon extract the heart and sent it to the specialized centre on required temperature and time frame. Once it reaches the specialized centre of transplant, the experts can extract valves by careful aseptic dissection from the donor heart. Then, valves are inspected carefully by the expert’s medical team for the suitability of that valve for preservation and future use in the patient.
After that valves are packaged in asepting allograft packaging and then stored at -150c in liquid nitrogen as freezed valve and they can be utilized in next 10 years.
Advantage of Valve Transplant
The benefit of human heart valve is that they are closest to natural and life saving. After transplantation, the patient does not require blood thinners which makes is particularly beneficial for young children, pregnant women and older age group. They provide excellent hemodynamic performance due to a more natural function of the surrounding structures.
However, with limited number of organ donors in our country, it is challenging to find homografts for the needy patients requiring valve transplant. It is indeed the need of the hour to develop homograft banks and raise awareness of valve transplant & organ donation.