The cardiology world is abuzz with the revelation of yet another clinical trial that has shown no added advantage with balloon angioplasty, compared to optimal medical therapy, in the treatment of patients with stable coronary artery disease (CAD).
After a decade of study, the results of the International Study of Comparative Health Effectiveness With Medical and Invasive Approaches (Ischemia) Trial were revealed at the American Heart Association Scientific Meeting 2019 in mid-November.
The study was carried out in 320 centres, involving 5,179 patients with stable CAD, who were randomly selected to have either medical therapy, or medical therapy with angioplasty or bypass surgery.
Judging from the response of colleagues worldwide, the results are somewhat controversial, but most agree that the study shows that the risks of death, heart attack and hospitalisation are no different whether the patient receives an angioplasty or bypass surgery, or optimal drug therapy alone.
CAD is a multifactorial illness brought about by the risk factors of smoking, diabetes, hypertension, high cholesterol and genes.
This results in the creation of plaques made up of cholesterol and inflammatory cells, on the walls of coronary arteries (arteries that supply blood to the heart), causing a narrowing of the artery.
When the narrowing has reached a certain level, chest pain may be experienced after physical activity, which will disappear with rest.
This is considered as stable CAD.
Assessment with a coronary angiogram will likely reveal a narrowing of over 70% in the coronary vessels, which can appear frightening to the patient.
Implanting a stent at this stage would immediately reduce the narrowing completely, probably much to the relief of the patient.
The important question is whether treating such a lesion with a stent will give the patient any added benefit, compared to just giving adequate drug therapy.
Surprisingly, the Ischemia Trial showed that in the group with stable CAD, a stent implant did not reduce the incidence of heart attack, hospitalisation for heart-related symptoms (e.g. heart failure) or death.
These patients did just as well with good medical therapy – a far cheaper and non-invasive alternative.
This means optimally controlling a patient’s blood pressure, blood glucose and blood cholesterol levels with medication, as prescribed by the doctor.
Unfortunately, many patients stop taking their drugs because of false information on the internet and advice from unqualified friends who tell them that drugs to treat high blood pressure and diabetes will damage their kidneys, although nothing could be further from the truth!
In fact, one of my patients recently came in with a heart attack after stopping his statins (for high cholesterol).
However, in cases of stable disease involving a narrowed artery that supplies a large area of heart muscle, most cardiologists would probably still prefer to do an intervention (e.g. stent implant).
It is, however, important to differentiate stable CAD from unstable CAD.
Usually after several years, for reasons that are currently unknown, the plaques in arteries may become unstable.
They can rupture, causing a 30% narrowing, for example, to become 100% within a matter of seconds, resulting in a heart attack.
This condition is classified as unstable CAD.
The Ischemia Trial is not applicable to this group of patients.
Unlike patients with stable disease, patients with unstable disease will benefit from urgent coronary angiography, in addition to good medical therapy.
Depending on the pattern of narrowings, these patients will then undergo angioplasty/stenting or heart bypass surgery.
In this situation, these procedures will save heart muscle and are often life-saving.
It is important to note that good control of diabetes and high blood pressure, as well as good lifestyle habits like regular exercise, weight loss and refraining from smoking, will prevent stable CAD from degenerating to unstable disease.
The Ischemia Trial provides proof that if you have stable CAD, there is no urgency for an intervention.
After undergoing an coronary angiogram, you can request for the the procedure to be stopped before a stent is implanted, in order to give you time to get a second, or even third opinion.
You should be absolutely sure that the stent is necessary.
Always remember, having a stent implanted in your heart comes with a price – they can create clots that can cause a heart attack, or even death.
A stented artery can still renarrow, in which case, subsequent treatment becomes more difficult.
Having a stent will also require you to take blood-thinners for the rest of your life, along with the risk of bleeding abnormally.
A good lifestyle and appropriate drugs in adequate doses to control metabolic abnormalities (e.g. high blood glucose) can give you many years of stable health without resorting to unnecessary procedures, if your CAD is stable.
Dr Kannan Pasamanickam is a consultant cardiologist. For more information, email firstname.lastname@example.org. The information provided is for educational purposes only and should not be considered as medical advice. The Star does not give any warranty on accuracy, completeness, functionality, usefulness or other assurances as to the content appearing in this column. The Star disclaims all responsibility for any losses, damage to property or personal injury suffered directly or indirectly from reliance on such information.
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