The human heart is a complex machine and delicate machine. We all know this, but the scale and complexity of this organ, the careful coordination of its various parts, and the balance that it creates between receiving oxygen-rich blood from the lung on one side, to deoxygenated blood from the rest of the body, and how this is exchanged continuously, every second, every minute, every day, is the miracle of human life.
Humans, and all mammals, require a lot of energy to go about their daily lives. This energy is in the food, but food will need to be burnt to release energy. And the way to burn this is oxygen. Oxygen in the blood is pumped throughout the body, which cells absorb to burn their food down and release energy. This deoxygenated blood then comes back to the heart.
This organ, the heart, is justifiably at the centre of everything we do. If even a small part or process of this machine is out of sync, human life unravels very quickly.
The Mitral Valve is a critical unit of the heart. It is situated near the left ventricle of the heart, and regulates the flow of blood between the atrium (upper two chambers of the 4-chambered heart) and the ventricle (the lower two chambers of the heart). The Mitral Valve allows blood to flow from the left atria, into the left ventricle, from where the blood is pumped into the main aorta which then supplies the rest of the body.
Any change in the way the valve opens and closes, or any leaks and gaps in it, could be fatal.
The valve degenerates over a period of time, that is, it becomes weaker and “more rigid” due to normal aging processes. Blocks could form, narrowing the opening between the valves, reducing blood flow. The Mitral valve could also develop problems due to other diseases, such as the Rheumatic Heart disease.
Indians, till recently, were at great risk of rheumatic heart disease. A large part of our population, especially from the more oppressed, disadvantaged communities, are at special risk of developing rheumatic diseases. Malnourishment, untreated common colds and throat infections, unhygienic environments, and more are contributing factors for rheumatic heart disease, and in turn mitral valve damage.
“In our country, next to heart bypass surgery, the most common heart surgery is this Mitral Valve surgery,” says Dr. MM Yusuf, a senior Cardiac Surgeon at Apollo Hospitals in Chennai. Dr. Yusuf specialises in minimally invasive surgery, aortic aneurysm surgery and heart transplantation. Over his long career, he has seen many complications of heart, and has successfully treated most of them.
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Improvement in general economic conditions, and advancements in medical science, and the greater access to primary and secondary health care in recent times, has reduced the number of patients with rheumatic diseases and mitral valve complications, but the surgery still remains one of the more frequent procedures doctors perform.
However, compared to western countries, say the US or the UK, the Mitral valve repair surgery numbers are lower in India. One big reason for that is the lack of expert surgeons, and the limited access to a fully equipped, advanced treatment centre or hospital.
Diagnosis to Surgery, providing excellent treatment and quality of care
Mitral valve conditions generally produce symptoms of breathlessness, or heart palpitations, racing of the heart, in patients. In such cases, a physician may order investigations such as the Echo Cardiogram. “Echo shows more than the physiological function of the heart. It shows the anatomy as well,” says Dr. Yusuf.
There could be stenosis - deposits and blocks on the valve, that narrow the opening and reduce blood flow into the ventricle, or it can be leaks in the valve that permit blood to flow in the opposite direction. Both conditions are dangerous and will need to be fixed immediately to prevent any long term damage or fatality.
Once a cardiologist makes a diagnosis of mitral valve damage based on Echo and other investigations, the patient is advised on options available, and informed consent for surgery is received. At this stage, a cardiac surgeon will need to decide between repairing the valve, and replacing. Both have their merits, and the right course of action is taken based on factors such as patients’ age, ability or indications for long-term medication such as blood-thinners, and other reasons.
“The reason to repair, and not replace, are two mainly. 1, the valve is attached to the left ventricle. When we replace those tissue attachments, in the long term it could lead to gradual loss of heart function. Whereas when we keep the tissues intact, and repair the valve, it retains the intact-ness of the pumping chamber - the left ventricle. 2. The other major reason for repair, is we can avoid the anti-coagulant tablets, which has risks of forming clots or alternatively, thinning the blood too much. Whenever possible, it is better to repair the mitral valve than replacing.”
Conventionally, all these were performed in open heart surgery. This was very risky. Splitting the sternum (rib cage protecting the heart) had higher mortality and morbidity rates. It is like a fracture to the rib, and takes 2-3 months to heal, during which time, the risk of developing complications are very high. Now in last two decades doctors are able to perform the surgery with minimal invasive procedures, with smaller incisions away from the sternum, near the fleshy part of the chest.
“In our centre at Apollo Hospitals, we are able to perform the surgery with video-assisted thoracoscope, and I am a specialist in this procedure.”
Strict Guidelines for Surgery, better patient outcomes
Patient is placed on a heart-lung bypass machine through the femoral artery and vein (near the groin). This allows the heart and lung to be “drained” of blood, without impacting the blood flow in other parts of the body. Doctors need a “clear field” - that is a heart that is not pumping or filled with blood, to perform the surgery. They make a small, 2 to 3 inch incision below the right nipple of the patient, a much smaller cut than one needed to open the sternum. Through the incision, they reach the chamber of the heart and the mitral valve, and repair the valve, or place a replacement. To assist them in the procedure, the thoracoscope transmits high-resolution video of the interior heart, allowing doctors to correctly guide their wires and instruments to the right area without impacting surrounding, critically important tissue.
Doctors also receive important inputs about the beating of the heart, the muscle capacity and other highly pertinent info, through the Transoesophagal Echocardiogram (TOE) in which a sound-sensitive probe is introduced into the oesophagus (throat) of the patient, and ultrasound image of the heart is produced. This gives Dr. Yusuf extremely critical, “live” information to assist him during the surgery.
“It is extremely important when we prepare the valve, and today, the guidelines of both the American College of Cardiology and European College prescribe TOE to make sure the valve is repaired, and is working well, and only then we can get the patient out of the theatre,” says Dr. Yusuf.
Together with the Video Assisted Thoracoscope (VATS) and the Transoesophagal Echocardiogram, Dr. Yusuf can “see” the heart without having to open a patient’s body up. “The operation is the same as open surgery, except the cuts are smaller.” VATS also is more cost-effective than other procedures available currently.
The benefits are much higher. Minimally invasive valve repair translates to a shorter hospitalisation and therefore, more cost effective. Patients can usually leave the hospital in under 4 days, whereas with open surgery, patients are usually made to stay at the hospital for 7 to 10 days. Recovery post surgery is also quicker, and within 2 weeks patients are back to routine daily life. Open surgery requires 2 to 3 months of convalescence for the sternum to heal and for the surgery to be fully realised.
Further, during the minimally invasive surgery, patients do not face the risk of blood loss, or require blood transfusion. This mean, risks associated with transfusion (infection transmission, or simply time taken to source blood donors) are completely removed.
Sometimes, doctors will replace the valve, instead of repairing it. There are two kinds of replacement valves available: one is constructed from animal tissue, the other is a mechanical device made of pyrolytic carbon leaves.
The mechanical valves last longer, compared to the bioprosthetic valves made of animal tissue. However, mechanical valves will also require long-term medication to regulate blood flow, as clots could easily form within the valve, and lead to strokes. Dr. Yusuf discusses all available options with his patients - and depending on their age, or contraindications for blood thinners, will advise one or the other valve.
This article has been produced by TNM Marquee in association with Apollo Hospitals.