With better equipment now, doctors are able to treat 100% blocked arteries using minimally invasive techniques that promise high success rates. By Michael Lim
LAST week was backbreaking but most rewarding as I worked with a team of experts over a two-day period to treat six patients with extremely complex heart artery disease who had refused open heart artery bypass graft surgery. Patience and persistence paid off as we managed to successfully open up the blocked heart arteries for all of them. All of the patients had symptoms related to blockage of their heart arteries and long standing total occlusion (also called chronic total occlusion or CTO) of the main heart artery (also called left anterior descending artery or LAD) to the main pumping chamber of the heart. Ten years ago, it would have been difficult to open their heart arteries which were 100 per cent blocked with minimally invasive techniques and five years ago, the success rate for treating CTO would not have been high. However, the rapid development of better devices and equipment to help doctors assess and treat heart artery disease, and increasing experience in treating complex CTO heart arteries have resulted in high success rates. Highly experienced heart specialists are able to achieve a success rate of close to 90 per cent during the first attempt at opening a CTO and this is achieved with a low complication rate.
Percutaneous coronary intervention
Opening a CTO is the most challenging procedure for heart specialists. The procedure is performed via a small puncture in the groin or wrist artery under local anaesthesia. Special plastic tubings are inserted through these minute millimetre openings and manipulated to reach the opening of the heart arteries. Iodine based contrast media is injected into the opening of heart arteries to visualise the moving heart artery under X-ray imaging. Using very specialised equipment and very special techniques, the completely blocked arteries are crossed with specialised minute wires and opened with balloon tubings and finally dilated with cylindrical meshes (stents) which may or may not be metallic. The procedure is called percutaneous coronary intervention or PCI. An important reason why patients are often referred to open heart bypass surgery is because the presence of CTO in one of their main heart arteries deters many heart specialists from performing PCI as the procedure can be very difficult with uncertainty of success.
Open heart bypass graft surgery
While in the past, most patients with CTO are often sent for bypass graft surgery, this trend is gradually decreasing. In addition to the higher risk of complications as compared to PCI, bypass graft surgery has other limitations. There are two common misconceptions that patients often have about bypass graft surgery. The first misconception is that bypass graft surgery results in the blocked arteries being cleared of the blockage. The facts are that the blocked arteries remain blocked and an alternative route is created by using the graft as a conduit to allow blood to flow from the aorta, through the graft, to the segment of the artery after the blockage. Often, the disease tends to progress in the blocked segment of the native heart artery, resulting in complete occlusion over time.
The second misconception is that after the bypass graft surgery, there will be no more heart problems. Data from the PREVENT IV trial, a study on failure of the bypass vein graft after surgery, published in the Circulation Journal in its end of September 2014 issue showed that almost 43 per cent of the patients with bypass heart surgery had significant occlusion of their vein grafts within the first 18 months after surgery. In addition, the five-year incidence of death, heart attacks or repeat procedure to treat blocked arteries occurred in 26 per cent of patients with death or heart attacks accounting for half.
PCI or bypass surgery?
A majority of patients opt for PCI. Not surprisingly, with the challenge of opening a completely occluded heart artery being met with high success rates and low complication rates of PCI, bypass graft surgery rates and repeat bypass graft surgeries have gradually decreased over the years. There are recommendations provided by international cardiology organisations, such as the American Heart Association and the American College of Cardiology, on the appropriateness for performing PCI procedures and bypass graft surgery for heart patients. Ultimately, the choice is influenced by whether the heart specialist is highly experienced in PCI, the subsidy policy of the medical facility, the insurance coverage, and the patient preference.
Not all blocked arteries need to be opened
While it is important to know whether your heart artery disease should be treated by PCI or bypass surgery or medication only, it is also equally important to know when PCI or surgery will not be beneficial. In a 2009 Cleveland Clinic study published in the Annals of Thoracic Surgery which studied 4,640 patients who had a patent arterial graft to the LAD and at least 50 per cent narrowing in grafts to the other non-LAD heart arteries, repeat procedures (whether PCI or bypass graft surgery) did not show additional survival benefit compared to medication. What this means is that as long as your blood supply in the LAD territory is sufficient, there is no additional survival benefit in trying to treat the other heart arteries by PCI or surgery. One will also not benefit from opening up a completely blocked heart artery if the heart muscle supplied by the heart artery has already been completely damaged by a previous heart attack.
Making the right heart decisions
When making decisions on your heart, go through a checklist for a safer decision.
• Safer Test: When you are suspected to have significant blockage of the heart artery, and you have been advised to undergo an invasive procedure to check your heart arteries through the insertion of plastic tubings through the wrist or groin arteries (procedure is called invasive coronary angiogram or ICA), you can save cost, reduce radiation exposure and avoid the potential risks of ICA (which also includes risk of heart attack and stroke) by opting for computed tomography (CT) scan of your heart arteries which costs a fraction of the ICA cost, is non-invasive, has lower radiation dose, is three dimensional and allows visualisation of the heart artery wall (not seen in ICA).
• Safer Option: Once you have been confirmed to have significant blockage of the heart artery, your physician will discuss the options with you. If you are given the option to undergo bypass graft surgery and you refuse, you may want to seek the opinion of a heart specialist who has significant PCI experience to discuss which is the safer option with better outcomes.
• Safer Outcomes: If you insist on PCI, you may want to check on the number of PCI procedures performed annually by your specialist as there are many published papers to show that experience makes a difference to outcomes and complication rates.
• Safer Choice: Before subjecting yourself to a PCI, check that the heart muscle supplied by the blocked vessel is viable. If the affected heart area comprises completely of scarred tissue, there is no benefit from doing PCI or surgery.
• Safer Results: If you have a CTO of a major heart artery, you will need to have a highly experienced heart specialist who has performed sufficient PCI procedures annually to meet international clinical competence criteria and has a good track record of success. As opening a CTO is an extremely difficult procedure with no guaranteed success, it is wise to choose carefully to ensure you give yourself the best chance of getting a good result.
Last but not least, always remember that the best decision is a carefully considered decision made after a thorough discussion with your heart specialist in the comfort of the clinic and not a hasty decision that you have to make while lying on the X-ray table after images of your heart artery have been taken during an ICA procedure while there is a tube still inserted into your groin or wrist artery.