Three factors make percutaneous coronary intervention the preferred choice – advances in PCI techniques, high occlusion rates of bypass surgery, and advances in diagnostic methods and increased patient awareness
FOR those with significant narrowing of one or more major heart arteries, opening of narrowed heart arteries using cylindrical metallic meshes (stents) that are mounted on balloons and inserted through 2mm plastic tubings via the wrist or groin artery under local anaesthesia is increasingly common. These stents are expanded and deployed at the narrowed heart artery segments and the entire procedure is called percutaneous coronary intervention or PCI. While performing PCI during an acute heart attack is undoubtedly life-saving, the data for those with blocked arteries but are relatively well or stable, is less robust.
The most important question is whether performing PCI in stable patients results in less death from heart disease. A recent February 2014 Circulation journal article by Mayo Clinic researchers on about 19,000 patients that had undergone PCI and were subsequently followed up for a long time sheds some light on this. These patients were followed up for almost two decades and by the end of the study period, 37 per cent of the patients had died. Death from heart disease decreased by 33 per cent but death from non-heart conditions such as cancer and other chronic diseases increased by 57 per cent. In this group treated with PCI, heart disease as a cause of death had gradually decreased in percentage over time.
PCI resulted in reduction in death from heart attacks and sudden death, but did not decrease death from failure of the heart pump function. This was because failure of the heart pump can also result from causes other than blockage of heart arteries. This study based on real world data showed that PCI is beneficial for those with significant heart artery disease even if they are relatively well.
The decision to treat a patient with severe blockage of his heart arteries with medication, PCI or heart artery bypass surgery is dependent on the patient’s overall condition, complexity of his heart condition, facilities of the hospital, financial considerations and last but not least the experience and capability of their heart specialist. Over the past decade, the incidence of heart artery bypass surgery has been decreasing and that of PCI has been increasing. There are three major reasons for these developments. The most significant is that advances in PCI techniques and increased operator experience has allowed PCI for complex heart disease to be performed safely. In today’s context, in experienced centres, PCI can be performed safely with good outcomes for most patients who have severe narrowing of all the three major heart arteries.
Recently, an overseas patient, Mr A, who had multiple narrowed segments in all his major heart arteries had been offered heart artery bypass surgery in his country and sought another opinion after failing to get his doctors to perform PCI for him. He refused surgery and after careful assessment with the help of a computed tomography (CT) scan of his heart arteries, PCI was considered as an alternative option. A CT scan of the heart arteries offered significant advantage as it provided important data on not only the lumen of the heart arteries but also the extent of cholesterol and calcium deposits in the wall of the heart arteries; information that cannot be obtained from an invasive coronary angiography (ICA) performed by injecting contrast media into the heart arteries by inserting plastic tubings through the artery at the wrist or groin. The vital information provided by the CT scan enabled the procedure to be performed successfully and safely.
Another overseas patient, Mr B, had 100 per cent blockage of two out of three of his major heart arteries and 90 per cent blockage of the third heart artery and had refused heart bypass surgery. Meticulous and detailed study of the CT scan of his heart arteries provided important three dimensional images and cross sectional images of heart arteries; information that could not be obtained from the two dimensional ICA images. Careful planning allowed the PCI to be performed successfully with good outcomes. It has been more than a year since the PCI had been performed and Mr B is able to run on the treadmill machine without any symptoms. More importantly, a follow-up scan showed that all his heart artery segments that were opened had remained patent.
Both Mr A and Mr B had new generation bioabsorble polymer cylindrical meshes implanted into the heart arteries. In addition to having a new lease of life, they both will benefit from the ability to stop taking blood thinning tablets after six months and the multiple polymer “stents” in their heart arteries would have been absorbed by the body after three years, restoring their arteries to their natural state.
The second reason for the declining incidence of heart artery bypass surgery has been the sobering outcomes from real world data. The high occlusion rate of venous grafts have resulted in loss of benefit after several years when compared to those who have been treated with medication only. For example, data from the USA Society of Thoracic Surgery 1991 to 2007 database, published in the Circulation journal in March 2013, showed that for those 65 years or more who had undergone heart artery bypass surgery, the benefits were lost after several years when compared to those who were on medication only. In addition, only 20 per cent of the patients were alive after 18 years of follow-up, with about half of them dying from heart disease.
Thirdly, advances in diagnostic methods and increased patient awareness have also resulted in earlier detection of heart artery disease which are usually either treated with medication or PCI and do not require bypass heart surgery. Nevertheless, there will be patients who present late with severe disease that would require heart bypass surgery rather than PCI. Hence, while heart bypass surgery is less commonly performed for heart patients, it remains an important option.
Hence, if you have been diagnosed to have severe narrowing of your heart arteries, scientific data shows that PCI can reduce death from heart disease in the long term. While bypass surgery seems to be beneficial for those with complex heart artery disease when compared to those on medication only, this benefit is gradually eroded over time. If all the three major heart arteries are severely narrowed, whether you undergo PCI or bypass surgery is not only determined by the detailed assessment of the heart artery disease but also by the facilities and experience of the centre. Hence, do not be surprised that if you present the same set of heart artery ICA films to different heart specialists, you may get different opinions.