Tuesday, 23 September, 2014

 
Published May 31, 2014
Wellness
The right path for your heart
Besides price, there are also other considerations that the informed patient should look out for when making decisions on the use of heart services
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EXAMINING ALL ANGLES
Making a choice purely on price alone may mean inadvertent exposure to unnecessary X-ray radiation or exposure to risks of life-threatening complications. - PHOTO: STOCK.XCHNG

BT 20140531 HEALTH31EK66 1112755

IN this Internet-connected society where information can be obtained at the click of a computer, there is an increasing trend for many services to be treated as a commodity where the main driver for decision-making is price. Healthcare services are not spared by this trend. Besides price, what else should the informed patient be looking out for in making a decision for the services best suited to his healthcare needs?

What you need to know about heart scans

This week Mr A, who is in his 50s, had chest pain for a few days and wanted to have a Computed Tomography scan of his heart arteries (also termed CT coronary angiography or CTCA) as he was concerned about the likelihood of heart artery disease. CTCA is a non-invasive outpatient procedure where an iodine-based contrast is injected into the arm veins and three-dimensional X-ray images of the heart arteries are taken within seconds. It is increasingly being used as an alternative to conventional coronary angiography (CCA) which involves the insertion of plastic tubes into the heart arteries to obtain images using X-rays. Over the last 10 years, the indications for the use of CTCA for the diagnosis of heart disease as recommended by the American College of Cardiology and American Heart Association have expanded rapidly to cover most areas of heart artery disease.

The main advantages of CTCA when compared to CCA are the following: no need for hospitalisation; no need for insertion of plastic tubes into heart arteries; about one quarter the cost; three-dimensional rather than two-dimensional; able to see the composition of the deposits causing the narrowing rather than just the lumen of the artery; much safer and lower X-ray radiation when using the newer CT scanners.

Mr A was well-read and thinking beyond price. He wanted to know about the X-ray radiation dosage he would be receiving during the scan and whether the test was accurate. A study of 50 hospitals in the US had shown that even when using the same type of CT scanners, the X-ray radiation dose of the CTCA varied significantly between hospitals. In the "worst" centre, the X-ray radiation received by the patient from one CTCA scan was equivalent to the total X-ray radiation of six CTCA scans in the "best" centre. The settings and experience of the centres vary and hence the radiation dosages are significantly different despite using the same type of scanners.

Most published studies on the accuracy of CTCA will show that most centres performing CTCA are correct when the scan is reported to have shown no narrowing of the heart arteries. However, when a CTCA report states that there is a significant narrowing of heart arteries, the accuracy can vary substantially from centre to centre. Generally, high-volume centres with highly experienced doctors who have reported thousands of scans will be able to produce more accurate reports than low-volume centres when similar scanners are used.

Hence, before exposing yourself to unnecessarily high doses of X-ray radiation, do some homework to understand the type of CT scanner being used, the estimated radiation dose you expect to receive during the CTCA scan, the experience of the centre and the predicted accuracy.

Mr A underwent CTCA with a radiation exposure of less than two milli-sieverts of radiation, which is equivalent to the additional radiation exposure received by flight attendants annually. The sievert (Sv) is used as a measure of the health effects of low levels of radiation on the human body (one Sv = 1,000 millisieverts or mSv). He was shocked to find that he had near total occlusion in two out of his three major heart arteries despite having only mild chest symptoms for a few days. CCA performed the next day confirmed the results of the CTCA scan and the blocked arteries were opened with stents. Happily, Mr A is now free from the risk of a sudden heart attack.

Avoiding unnecessary invasive heart tests

CCA continues to be a commonly used test. Papers published in the last few years have come to the conclusion that CCA is over-utilised as a diagnostic technique and alternatives should be considered. As it is invasive, expensive, requires hospitalisation and carries real risk, including heart attack, stroke and death, it must be considered carefully before being used as a diagnostic tool.

The USA CathPCI registry, the national registry for CCA and Percutaneous Coronary Intervention (also termed PCI, which refers to the procedure of the opening of heart arteries with minimally invasive tube-based techniques such as balloon catheters or stents), obtains data from 691 participating centres in the US. It provides interesting data that shows significant differences between centres. The likelihood of finding the presence of significant narrowing of the heart arteries for every 100 CCAs performed in the centres varied from 23 to 100.

Real risk of complications

Compared to centres with a high likelihood of finding significant heart disease using CCA, those with low likelihood of finding significant diseases on CCA are more likely to perform CCA in those who are younger, women, of lower-risk profile, and with atypical symptoms.

Interestingly, the registry data showed that whether it was a private or a university centre made no difference to the likelihood of detecting disease on CCA.

A study in the Journal of the American College of Cardiology published in August 2011 reported that the usage of CCA as a diagnostic tool was also affected by the different healthcare practices in different regions with 83 per 10,000 in US, 12 per 10,000 in Netherlands and 26 per 10,000 in the UK. Hence, if you are young or are a pre-menopausal woman, have a low risk profile, do not have typical exertional chest pain symptoms, have no documented heart disease by other non-invasive diagnostic tests and are offered to undergo CCA at a low-volume centre, you may want to think twice before parting with thousands of dollars, enduring pain and subjecting yourself to a procedure that carries a small but real risk of complications. You may want to consider cheaper, non-invasive and safer alternatives.

The American College of Cardiology Foundation and the American Heart Association issued a statement on the competency to perform PCI in 2013. They reported that centres which perform fewer PCI procedures have a greater incidence of major adverse complications such as death and emergency heart bypass graft surgery.

It was also reported that data from the CathPCI registry that looked at more than 300,000 PCI procedures performed by over 3,600 physicians showed that those who performed less than 75 PCIs per year had a significantly higher incidence of in-hospital deaths compared to those who performed more than 75 PCI procedures a year.

Another study reported in the paper which took 90 PCIs a year as the threshold categorising physicians into low-volume and high-volume operators showed that patients treated by low-volume operators had a 63 per cent increase in complications, including death, heart attacks, stroke, bypass surgery and repeat PCI.

The current recommendation is that interventional cardiologists perform a minimum of 50 PCI procedures per year (averaged over a two-year period) to maintain competency. Beyond the absolute numbers, highly experienced and skilled interventional cardiologists with high volumes can perform highly complex PCI procedures for severe heart artery disease with very low complication rates and good long-term outcomes.

However, even the best and most experienced operators will invariably have complications during PCI procedures and hence patients need to understand that there is no such thing as a risk-free PCI. However, as undergoing a PCI implies a potential risk of serious complications, ideally, one would want an interventional cardiologist who has many years of experience of doing complex PCI for complicated diseases of the heart arteries, has high PCI volumes and a low incidence of complications and good long-term outcomes.

While price remains an important consideration when making decisions on the use of heart services, there are other important considerations which are equally if not even more important. Making a choice purely on price alone may mean inadvertent exposure to unnecessary X-ray radiation or exposure to risks of life-threatening complications. Remember to do your homework before making that decision - you will not regret it.

Dr Lim is medical director at the Singapore Heart, Stroke & Cancer Centre. He is also editor-in-chief, Heart Asia (a journal of the British Medical Journal Publishing Group); chairman, scientific advisory board, Asia Pacific Heart Association; and honorary professor and senior medical adviser, Peking University Heart Centre

This series is brought to you by Heart, Stroke and Cancer Centre. It is produced on alternate Saturdays.

To read more of Dr Lim's previous health-related articles, please visit: http://www.btinvest.com.sg/specials/shscc