If you need to go for a balloon or stent procedure, it is best to find out how much experience your specialist has. By Michael Lim

IF you have chest pain and have been found to have significant blockage of your heart arteries, you can opt for only medication, open heart bypass surgery or a procedure to open blocked heart arteries with balloon catheters and stents (miniature cylindrical meshes that expand to open up blocked artery segments), also termed as percutaneous coronary intervention or PCI.

Medication versus procedure

A few months ago, there was a discussion on the treatment options for heart patients in my class Facebook account which was open to all my medical school ex-classmates. An ex-classmate, who was a family physician, was of the view that all patients with heart disease should only take medication and should not opt for PCI or open heart bypass surgery. He opined that since heart patients needed only medication, no testing was required. He formed his views after looking at the conclusions of two studies called the COURAGE trial and the BARI 2D trial which appeared to show that medication alone was as good as the other two options for patients who were stable.

However, the problem with reading conclusions of studies without looking into the flaws and subsequent follow-up to the studies may lead to skewed conclusions. What my friend did not know was that one third of the patients who took medication eventually had to have PCI or bypass surgery. Hence, PCI or bypass surgery was not prevented by medication but rather deferred for one third of the patients. Many of the patients who were considered for the two studies were not enrolled when tests found that they had severe symptoms and complex heart artery disease. They were promptly sent for PCI or bypass surgery. Hence, those enrolled in these two studies had generally less severe heart disease.

The simple message is that medication works well for those who have no or minor symptoms of heart artery disease. Those who have severe symptoms and/or severe heart artery disease involving major heart arteries may benefit from PCI or bypass surgery, and this is substantiated by evidence from published studies. With the rapid advancement in technology over the last decade, the number of patients being sent for bypass surgery has decreased globally and increasingly more patients are opting for PCI. In line with these changes, guidelines and appropriateness criteria have been drawn up to help physicians provide advice to patients as to the choice of treatment but increasingly, most patients favour PCI.

Competence criteria

While heart specialists have to undergo years of specialised training before they can perform PCI procedures independently, the outcomes and complication rates can differ depending on their experience and the number of procedures they perform annually. To ensure that these heart specialists continue to maintain their competence to perform these procedures, guidelines have been issued.

In 2007, the American Heart Association, American College of Cardiology and Society of Cardiovascular Angiography and Interventions issued a statement to recommend that PCIs should be performed by heart specialists who perform more than 75 PCIs per year. However, with better medical care and more preventive health programmes, the number of procedures performed by trained heart specialists in the USA have fallen in the past decade. In the USA, the median heart specialist PCI volume declined from 53 annually in 2005 to 33 annually in 2009. In the light of these developments, in 2013, the three American cardiology organisations issued a new guideline recommending a reduced minimum competence requirement of 50 PCIs per year (averaged over a two-year period) for heart specialists performing PCI.

Incidence of complications

In September 2014, a research paper published in the Circulation Journal addressed the question as to the impact of the experience of the heart specialists on the outcomes of PCIs. The study examined in-patient records from a national database in the USA and included about 46,000 elective, urgent or emergent PCIs in the study. The overall death and complication rates were 1.08 per cent and 7.10 per cent, respectively. The common complications were injury of groin or wrist artery and bleeding complications (2.01 per cent), procedural related heart artery complications (1.69 per cent), stroke (0.99 per cent) and acute kidney failure requiring dialysis (<0.1 per cent).

As all PCI procedures carry a real risk of potential complications, the question is whether the annual volume of PCIs performed by these specialists have a significant impact on outcomes.

Impact of procedural experience on complications

The study divided the heart specialists based on their annual procedural volume into four quartiles; first quartile (<=15 PCIs per year), second quartile (16 to 44 PCIs per year), third quartile (45 to 100 PCIs per year), and fourth quartile (>100 PCIs per year). Death rates and complication rates decreased significantly with increasing quartiles of heart specialist procedural experience. The death rates were about 17, 12, 9 and 6 deaths for every 1,000 PCIs performed for heart specialists in the first, second, third and fourth quartile respectively. The complication rates were about 101, 72, 60 and 52 for every 1,000 PCIs performed for heart specialists in the first, second, third and fourth quartile respectively.

If this data is adjusted to take into consideration the recommended number of procedures performed annually for specialists to be considered competent based on the recommendations of the three American cardiology organisations, the death rates following PCIs by heart specialists performing <50 PCIs/year, 50 to 75 PCIs/year, >75 PCIs/year were 13, 8 and 5 respectively for every 1000 PCIs performed. Complications following PCIs by heart specialists performing <50 PCIs/year, 50 to 75 PCIs /year, >75 PCIs/year were 92, 64 and 57 respectively for every 1,000 PCIs performed.

Given that data from the USA indicated that more than half the heart specialists performing PCIs five years ago do not even meet the newly recommended clinical competence number of 50 PCIs per year, with the decreasing PCI volume, it means that the large majority of heart specialists performing PCIs in the USA still do not meet the reduced minimum competency criteria per year. In reality, this is the situation in most countries.

Right decision for best outcome

What it means is that on an overall basis, the risk of death and complications performed by an operator with less than 50 PCIs per year is about double that of an operator with more than 100 PCIs per year. If you compare those in the first quartile with those in the fourth quartile, the death rate is almost three times higher.

An experienced operator is more likely to be able to perform complex PCI procedures involving occlusion of all the major three heart arteries with low risks whereas a low-volume operator is unlikely to perform complex procedures and are more likely to send these patients for open heart bypass surgery. While a low-volume operator may insist that bypass surgery is the only choice for the heart patient, a high volume operator may be able to treat the heart condition with PCI with a much lower risk of complications and good long term results. Hence, it may be a good idea to get another opinion if you are uncertain.

If you have chest pain and significant blockage of the heart arteries, you should discuss the options with your doctor. If PCI is an option, you may wish to do some homework including understanding the experience of the specialist performing the procedure, whether he has been regularly meeting the competency criteria in recent years, the number of procedures performed annually, the complication rate, experience in performing complex procedures, type of stents that will be used and the ability to discontinue blood thinning medications after stenting.

Finally, the need for life-long consumption of blood thinning medication when using less costly conventional stents must be weighed against the ability to discontinue blood-thinning medication after the initial period when more costly new generation stents are used. Discontinuing blood thinning medication for conventional stents may result in blood clot formation in the heart resulting in a heart attack. Being able to discontinue blood-thinning agents permanently after stenting with new generation stents means that you are not putting yourself at risk of bleeding during surgery and there will be hardly any risk of clot formation in the stents. Remember, making the right decision can mean getting the best outcome.