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Aortic Aneurysm Repair using EVAR/TEVAR procedures is providing hope for high-risk patients.

When minutes and seconds count expertise matters Treating a heart aneurysmUS Air Force photo/Ilka Cole
Wednesday, November 08, 2017 - 09:14

 

By all counts, Indians are at high risk for heart diseases. Our rich food, and sedentary lifestyle - especially in urban areas - puts us at risk of high blood pressure and other heart ailments. The high blood pressure in turn impacts other areas of our circulatory system. General public awareness about aneurysms of blood vessels in comparison with heart attacks is largely low.

An aneurysm is a condition in which the blood vessel loses its elasticity (ability to stretch and return to accomodate blood flow), becomes weak and overstretched, and bulges out. Any swelling of the aorta greater than 3 cm in diameter, or more than 50% of the normal size of the vessel, is termed an Aortic Aneurysm - AA. Those that occur near the kidneys and abdomen is called the Abdominal Aortic Aneurysm - AAA, and those above the kidney - closer to the heart, is called a Thoracic Aortic Aneurysm.  

While normally Aortic Aneurysm may not cause any visible symptoms, and may not be palpable even by doctors on routine examination, a screening ultrasound of the abdomen is needed in patients with risk factors to identify the disease at an earlier stage.  Acute Aortic Syndrome is a masquerading disease, often misdiagnosed because of its varied presentation as hoarseness of voice, difficulty in swallowing, weakness of lower limbs, back pain. Patients often end up getting treated by doctors of other specialties. This usually results in late diagnosis and patients often present as emergency, as the weakened artery wall could further degenerate and could rupture at any moment, leading to a severe loss of blood, a drop in blood pressure, and passing out. The chances of rupture go up further, as the size of the aneurysm becomes bigger.

Over 7cm in diameter, the risk of rupture is 33% with mortality rates being 90% according to currently available data. Indians are at high risk of AAA. Since 1990, the risk of contracting AAA, and dying as a result of it, has increased by 40% and more. One study finds that aortic diseases - especially aortic aneurysms - are more common as the Indian population becomes older.

Dr Y Vijayachandra Reddy, popularly known as YVC, a senior interventional cardiologist at Apollo Hospitals in Chennai, knows the risk, and is prepared to meet it. Dr YVC is a leader in emergency EndoVascular Aneurysm Repair - EVAR, and Thoracic Endovascular Aneurysm Repair - TEVAR.

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EVAR/TEVAR: The difference between life and death

Repair of aneurysm (done as early as 1990) earlier meant complicated open surgery, where surgeons will have to cut the swollen section of the aorta, and replace with a graft, and restore blood flow. Open surgical repair is associated with its own risks especially with possible injury to blood supply to spinal cord which could result in paraplegia. Recovery from open aortic surgery is usually longer and patients will need to be closely monitored for a long time after, to ensure they develop no further complications.

However, EVAR and TEVAR, have changed all that. Dr YVC says, “EVAR/TEVAR has revolutionised the treatment! Previously, aortic aneurysm repair could only be done surgically. Mortality and morbidity was extremely high. Now, we can do this minimally invasive technique called Total Percutaneous repair.”

Under the EVAR procedure, Dr YVC will make a small needle entry - an opening - near the groin of the patient, and insert specialised vascular sheaths. The doctors then will approach the aneurysm using a catheter (wire), cross the point where it is at its widest, and deploy an Endograft - a tube-like stent, that will act as a new channel for blood to flow, relieving pressure in the aneurysm. This will then allow the aneurysm to clot-off, and reduce in size.

Once an endograft is put into place, and is precisely positioned using high-resolution imaging of the blood vessel, doctors remove the sheaths and wires, and close the opening.

Dr YVC and others perform two kinds of Aneurysm repair. One is Total Percutaneous Repair, in which a needle entry in made into the femoral artery, and special sutures are placed over it. Once the EVAR procedure is complete and the catheter is withdrawn, the sutures are tightened and the point of entry is sealed. This procedure leaves no marks or scars at the surface. The second kind is when a surgeon may be required to expose the artery in the leg or groin area, after which doctors introduce the catheter. This technique is mainly used when the arteries are too thin or not easily accessed by catheters.

The entire procedure takes about half an hour, and patients recover faster and are able to function fully, in a much shorter time than open surgery, and develop fewer complications in the long term.

Sometimes, doctors may place more than one endograft, depending on the size of the aneurysm. Additional supporting grafts may also be placed at points below the aneurysm where the aorta branches into two, thereby further strengthening the blood vessel, and reducing the chances of the aneurysm descending. When aneurysms occur in the chest, or thoracic region, doctors mostly use just a single tube graft. However, the abdominal aorta branches into two near the groin, and doctors will need to clear both the branches simultaneously. Here, a Y shaped graft is constructed using a main body graft, and a connecting smaller graft at the point of branching.

“Previously when this technology came, only ideal cases were treated, but now with our expertise we are able to treat 95% of aneurysms - at the thoracic or abdominal aorta, with TEVAR and EVAR only!” says Dr YVC.

The doctor has also seen instances where aneurysms occur simultaneously in the chest and abdomen areas, which calls for a combined EVAR and TEVAR procedure.

An ideal case, till recently, meant that the aneurysm developed in a very specific zone in the aorta, giving surgeons a “landing zone” in which to place their grafts. Aneurysms had to be positioned at least 1 cm below the kidney artery, and preferably 1 cm above the internal iliac artery - the main artery supplying the pelvic area.

However, Dr YVC and other cardiologists are now able to perform the aneurysm repair even when they occur outside the landing zone, at the renal artery, or the intestinal arteries. Specialised stents and grafts - a Chimney stent, Fenestration, or Branched Grafts - allow the doctor to cover the aneurysm but still retain blood flow to critical organs in the body. A chimney stent is particularly used when the aneurysm forms over the branched artery. This condition required open surgery till recently, complicating risks. But under the minimally invasive EVAR or TEVAR process, chimney stents are deployed over the point of branching, allowing doctors to relieve pressure in the aneurysm without cutting off blood supply to other parts of the body.

Dr YVC says, “Some of the aneurysms we’ve seen, are giant aneurysm. Sometimes at sizes not reported anywhere else in the world.” One such instance which Dr YVC repaired was about 143 millimeters (14 cms - twice as the highest risk 7cm reported earlier). This bulge filled almost half the chest cavity, says Dr YVC, and performing the TEVAR procedure was complicated, but ultimately very successful.

He also has a lot of  experience in Hybrid EVAR/TEVAR procedures. Not very common, the hybrid procedure is usually performed when the branch vessels cannot be done through these techniques and a debranching bypass graft is usually done in the theatre by the vascular surgeons and subsequently, the patient is shifted to the cathlab where additional grafts are placed using EVAR/TEVAR techniques.

“Previously they may have had to go for total surgery. Surgery is highly risky,” says Dr YVC. One of the potential negative result of surgery, especially to treat a thoracic aneurysm, is paralysis of the legs. Blood flow had to be completely cut off during the surgery, causing the lower body to go into paralytic shock. But with TEVAR and EVAR procedures, the chances of that happening is less than 2%.

Dr YVC is particularly experienced in performing these procedures on high risk patients.

While EVAR / TEVAR procedures were created to repair aneurysms, the technology is also now used for other conditions where the blood vessel needs emergency repair. An aneurysm may not be present, but the artery’s walls could be torn, or holes may have formed between the inner wall of the artery and the outer wall, causing blood loss and potentially death. “There is a parallel disease called aortic dissection. This is not an aneurysm, but a tear in the artery. The general public confuse between the two, but they are different.” The dissection is an acute event, says Dr YVC. In that, it occurs suddenly, and could be fatal if not recognised in time.

Dissections which occur near the origin of the aorta call for surgical repair, but dissections in other parts can be treated with EVAR/TEVAR procedures. Some of the dissections over a long period of time, could develop into aneurysms.

Road accident victims may face aortic disruption - a tear on the inner wall of the artery. This will require instant, emergency repair. Seconds are crucial, and a doctor’s skill will mean that the patient can survive and recover. “Trauma related aortic disruption is highly catastrophic! If they survive and reach a hospital, it is important to recognize the condition and place a stent. This is an emergency EVAR procedure,” says Dr YVC. While this may be rare, with only a few hospitals and institutions reporting such instances, the number of road accidents in the country (Tamil Nadu and Karnataka are at particularly high-risk for road accidents) requires doctors to be aware of such a scenario and take prompt actions to save lives.

Providing Hope, with Protocol based management

For complex procedures like EVAR and TEVAR, and in emergency cases - ruptured aneurysms, heart attacks, or road accidents, time is of the essence. This requires the entire medical team and support staff to know the ins and outs of every procedure perfectly, and for every member to cooperate with each other. There must be no gaps or misses in the processes, and surgeons have any and all information at short notice.

This is where Apollo, and Dr YVC’s team, excel. The Cathlab - Catheterization Laboratory - in Apollo, where catheters are inserted into the arteries to enable life saving procedures to be performed - is always on call. Not only the technicians, but the senior consultants too, are available 24x7. Secondly, the lab is equipped with the most refined of devices and technologies - assistive devices such as ECMO. Thirdly, the technical expertise, and experience of the doctors, consultants and support team is at the highest level.

“Ours is a tertiary centre - patients who’ve been to other hospitals and are referred to Apollo, because we have greater expertise. They’ve been told they need surgery, but there is risk. What we do is comprehensive analysis. The most important thing here is to see the patient in toto - not only the heart, but other systems,” says Dr YVC.

All this means, that when a patient is referred, they can be assured of the appropriate care, and more importantly, timely care. 

This article has been produced by TNM Marquee in association with Apollo Hospitals.