Aga Khan University Hospital, Nairobi Unveils a New Technique to Image the Inside of Blocked Heart Arteries​​​

Aga Khan University Hospital, Nairobi unveils a new technique to image the inside of blocked heart arteries​​​

May 24, 2013

Traditionally the most common form of heart disease in the world and in Kenya has been rheumatic heart disease caused by bacterial infection and subsequent damage of heart valves through an indolent immunological process. This illness affects young children and adults with peaks at the ages seven years in children and young adults in their third decade.

However, as communities develop with improved sanitation and better medical services, a transition occurs whereby rheumatic heart disease is relegated to the background and coronary artery disease begins to rise. Kenya is in a transition zone where people are dusting off rheumatic heart disease in favour of coronary artery disease. The Vision 2030 will surely come with its fair share of spoils.

The Aga Khan University Hospital, Nairobi has been a regional pacesetter in the field of cardiology. With coronary artery disease continuing to affect more young Kenyans and the tide being on an upward surge, the Hospital continues to foster new technologies and therapies that have proved successful in other parts of the world.

For the first time, cardiologists at AKUH, N carried out a procedure known as Intravascular Ultrasound (IVUS). As Dr Mohamed Jeilan, an Interventional cardiologist at AKUH, N described it, “After performing a coronary angiogram, using a key-hole technique, we introduced a tiny ultrasound probe into the inside of our patient’s coronary artery and watched the moving images to assess the lining of the artery from the inside. The procedure allowed us to decide whether the inner lining of the artery had been damaged significantly and whether a stent should be placed in the artery to improve healing of the artery. This special catheter allows us to visualize the inside of the heart artery and take pictures which doctors can use to analyse the type and mechanism of narrowing in the artery.

This helps to determine the amount of blood clot in the vessel (heart attack occurs when a blood clot forms and occludes an already narrowed vessel) and the degree of narrowing caused by cholesterol deposition in the vessel. It also guides the doctor to establish the most appropriate method to treat the diseased vessel".

Dr. Mzee Ngunga, a Cardiologist at AKUH, N, explained, “For example if the vessel is not very narrowed and there is a lot of clot then the vessel can be treated with medicine that helps in the dissolution of the clot. The first patient for whom the AKUH, N cardiologists performed the IVUS procedure fell into this category. The advantage of this treatment approach is that the patient is saved the insertion of a stent (a small mesh tube that is used to treat narrow or weak arteries) and accorded the benefit of medical therapy.”

“In the IVUS procedure, doctors use a wire which is advanced into the heart artery over a guide catheter. Over this wire the IVUS catheter is introduced into the diseased vessel. The tip of the catheter has a marker that acts as a guide. The second part of the catheter has an ultrasound probe that images the vessel to give an outline of the vessel including the cholesterol plaque, clot and any calcium in the vessel.”

“The IVUS catheter comes at the most opportune time for clinicians at the AKUH, N because they will use this procedure to improve the treatment of patients with heart attacks. In addition they will utilise the same catheter to achieve good results when doing complex procedures which involves putting stents in the main vessel of the heart where placement of the stent with high accuracy is paramount.”

Explaining the journey and history of the treatment of coronary artery disease, Dr.  Mzee Ngunga said, “The traditional approach to the treatment of blocked and narrowed heart arteries is the use of bypass surgery. In this procedure that was first performed in the USA in 1960 the surgeon saws open the sternal bone to expose the heart.

He harvests veins from the legs and uses an artery on the chest wall to bypass the blockages by implanting new conduits directly from the aorta past the area of blockage. This way he creates a new vessel and leaves the old vessel as it was.”

“This technique remains a great method to treat blocked or narrowed arteries but it cannot be performed immediately and completed in a few minutes as needed for patients with heart attacks. This is why we have percutaneous coronary intervention (PCI). This procedure was first performed by Dr Andreas Gruentzig in Switzerland in 1977. Since then it has advanced greatly and is performed in many hospitals by cardiologists around the world.”

“This technique involves the use of 2-3mm wide and 100cm long catheters to access the heart through the great arteries and using razor thin wires to deliver stents to open the narrowed or blocked artery. Visualization of narrowing (s) or blockages is facilitated by use of X-ray and contrast dye to opacity the blood vessels. The other advantage of this technique is that most patients can leave hospital on the same day or on the next day. After the procedure the patient can walk around in an hour, or so without any discomfort in contrast to surgery where the patient is confined to the intensive care unit for up to one week.”

“At the Aga Khan University Hospital we use the large artery at the wrist or the groin to access the heart arteries. This technique is done quickly and in the setting of heart attack we endeavour to complete the process within one hour to one hour and half after the development of chest pain.”


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