Knowledge

Why more and more people undergo Coronary Angioplasty compared to Bypass Surgery in the recent times?

In the early 70s, if a person had a blocked artery supplying the heart, he had only one option, which was medical treatment. This just controlled the symptoms arising from the disease. It did very little to treat the primary problem. There simply was no definitive treatment for Coronary Artery Disease.

By the 70s, bypass surgery had become popular as a treatment modality for this problem. But then, the mortality (probability of dying during or after surgery) was around 5% or more. So it was concluded that if the patient had only one blocked artery, the risk of surgery outweighs the risk of having the problem and hence treating it medically was the option. Surgery was confined to severe multiple blocks which posed a higher mortality than the bypass surgery itself.

As years passed, the risk of surgery decreased to 2-5% in the eighties. At this time, angioplasty was in its infancy. The way it was done was by using a balloon to dilate the blocked segment. This gave good short term results. But it had a probability of blocking again, which was about 35% - 40%. Again, it was limited to 1 block because the probability would increase with more blocks treated with balloon only. So, bypass surgery continued to dominate the treatment for multiple blocks and severe blocks.

By the late nineties, stents were introduced into interventional cardiology which changed the face of treatment for coronary artery disease. These stents were made of stainless steel and had no special drugs coated on them (hence called Bare Metal Stent - BMS). With the introduction of stents, the probability of blocks reappearing (called restenosis) in an artery treated with angioplasty and stent came down to 25%. This made angioplasty feasible for more people with more severe disease. Also, the surgical mortality had come down to around 2-3%. At this point, both options were equally effective for simple blocks, even if there were more than one block. One problem still remained. Patients who had diabetes had higher probability of the stents blocking again (restenosis). Based on this fact, surgery was still a better option for patients with diabetes, especially for those with multiple blocks.
By 2005, the new generation of stents called Drug Eluting Stents (DES) were available for clinical use. These stents were coated with special drugs that prevented the blocks from developing inside the stent. This drastically changed the treatment for blocked arteries. The restenosis rate came down to 3-5%. At this point the long term results (at the end of 10 years after the index procedure) of surgery or angioplasty were the same, irrespective of the number of blocks and the presence of diabetes. Now the challenge was more of the ability to perform the angioplasty perfectly and give excellent results on the table, which translates to better long term results, than the limitations of the stents, wires, catheters and imaging technologies.

Moreover newer techniques combined with advanced coronary hardware helped cardiologists open 100% blocked arteries. For the last decade, more and more 100% blocks, that were considered impossible to open by angioplasty, are opened using special techniques that are taught to the world by the Japanese cardiologists. Japanese cardiologist have mastered this technique since the Japanese people are unwilling to undergo bypass surgery, based on their belief that their soul will depart, if the chest is opened during bypass surgery. This has forced the Japanese cardiologists to develop better techniques and skill to perform these angioplasties. The newer retrograde technique has revolutionised the art of doing angioplasty for 100% blocks (called Chronic Total Occlusion- CTO).

The other holy grail of interventional cardiology was the Left Main Coronary Artery (LMCA) disease. People with blocks in Left main artery were considered only for bypass surgery a decade ago. Today angioplasty can treat most of these left main artery disease. There are large scale trials (SYNTAX trial) supporting these treatment modalities. Again, the key here is the ability of the performing cardiologist to give a perfect procedural result. The skill of doing the procedure to perfection is not something that every cardiologist possess. This skill is a combination of clear understanding of the anatomy, very objective thinking, good infrastructure and of course, a gifted pair of hands.

As of today, there are very few patients who cannot be treated with angioplasty. The inability to do angioplasty for some of the patients who are advised bypass surgery is predominantly a combination of the complex anatomy of the blocks, the presence of severe calcium deposition and the lack of experience for operating cardiologist.

Surgical mortality is between 1-2% today, mortality from angioplasty is very low, at 0.5 - 0.7%. This makes angioplasty the procedure of choice for most patients with Coronary Artery Disease. The concept of living with one block because 'it's just one blocked artery' is no longer acceptable since the risk of angioplasty is significantly low.

To conclude, I believe that most patients should be offered coronary angioplasty with the newer stents and the ones who cannot have good results with angioplasty, even under skilled hands, should be offered bypass surgery.