For patients who have several blocked arteries around their heart, the gold standard treatment has long been coronary artery bypass surgery (CABG). But some time ago a large clinical trial suggested that angioplasty (PCI) with drug-coated stents (springy lattice tubes used to prop open clogged arteries) may also work well in patients with multiple blockages. And in some patients, the stents produce equally good results with faster recovery times. The study, which was published in The New England Journal of Medicine, brings to light important trade-offs that people with complex coronary artery disease need to weigh before making a decision between the two procedures.
A powerful randomized controlled comparative study between PCI and CABG in patients with multivessel blockages known as “SYNTAX” tells us that PCI is equal to CABG when the “syntax score” is less than 22. So whenever you have multi-vessel disease doctors can make a considered decision after they calculate what is called the “syntax score”.
If it is less than 22 angioplasty with stents is better. If the score is more than 22 then bypass is better. The SYNTAX score is the sum of the points assigned to each individual lesion where the coronary tree is divided into 16 segments according to the American Heart Association classification. Each segment is given a score of 1 or 2 based on the presence of disease and this score is then weighted based on a chart. “SYNTAX” is a path breaking study which made us think more rationally when faced with multiple coronary blockages. But in “diabetics” it may be a different story. On the basis of “SYNTAX diabetic study” and another powerful study called the “FREEDOM study”, the AHA (American Heart Association) gives a class I recommendation for CABG over PCI for patients with multi-vessel disease and concomitant diabetes mellitus. In other words bypass is better than angioplasty in diabetics with multiple coronary blockages.
A few days ago, one of the dailies brought a front-page article with a very scary and regrettable title, “Too many stents can kill you”. An audit of angioplasty cases performed in Maharashtra under the “state’s free insurance scheme” apparently showed that multiple stents were associated with a higher risk of death. The audit, published in the international medical journal “PLOS One”, found that 4.5% of the 4,595 patients under the Rajiv Gandhi Arogya Yojana who were studied, died within a year of angioplasty. Most deaths had occurred in patients with multiple stents or longer stented segments of arteries.
The study said total stented length greater than 31.5 mm was associated also with a higher mortality. On the other hand, similar studies in the West reveal only 1% mortality. Not all doctors agree with the findings of the Indian study. It is pointed out that “state government” and other “subsidised coronary intervention studies” mainly include small centers where the possibility of using bare metal stents (first generation stents) is higher and where more often than not relatively inexperienced cardiologists are on the job. This will obviously lead to skewed results.
One important point that interventionists must always keep in mind is that every blockage that is over 70% need not to be immediately stented. Interventionists are not plumbers, to be sure. Only those blockages that cause pain or other “physiological” evidence of blood flow compromise ought to be stented regardless of the percentage of blockage revealed by a coronary angiogram.
The present practice across Indian hospitals is to announce that a patient has three-vessel blockage and that he/she would require, say, three or more stents. Cardiologists need to first locate the problem blockages and only tackle those. At present, most interventionists do a visual assessment of the blockage and alas! – they stent it. In the West and Indian metros, stress tests, nuclear scans or sophisticated techniques such as fractional flow reserve (FFR) are used to establish if a blockage is indeed so huge that it prevents complete blood flow. And that’s the way to go!
Years ago, if a patient with multiple coronary blockages came and asked my advice I would tell him to undergo a CABG. “It is cheaper in our setting and the results are long-lasting”, I would say. Today, I think rather differently. Just like we have the low-rung surgeons performing substandard CABGs with bad results, we have even in our country, the first-rung angioplasters who are very dexterous in tackling complex lesions with stents for a durable result.
We can expect even better results in future since new research in the West is now focused on longer stents. The longest stent at present is 48mm but there is talk of a 60mm stent being soon introduced.
To sum up, optimum therapy in patients with multiple coronary blockages takes into consideration the role of clinical judgment and use of tested methods with a view to achieve successful outcomes. But, as concerned care-givers that we purport to be, we doctors ought to respect uppermost the patient’s personal choice of interventional procedure (whether PCI or CABG) after explaining to the sufferer the pros and cons in the light of currently available scientific evidence.
(Dr. Francisco Colaço is a seniormost consulting physician, pioneer of Echocardiography in Goa.)
