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Sunday October 21, 2007
By LIM WEY WEN
Surgery to rectify problems caused by clogged up coronary arteries are common. But how long do these interventions last, and when should a person get a repeat procedure, if that’s at all necessary?
SIX weeks ago, our nation prayed for the recovery of former Prime Minister Tun Dr Mahathir Mohamad from his second coronary artery bypass some 18 years after his first.
In retrospect, the event effectively dispels the myth that coronary artery bypass is a curative solution to coronary artery disease (CAD).
Dr David KL Quek, a consultant cardiologist also based in KL, concurs.
“Even in bypass surgery, for example, our former Prime Minister who had his first bypass some 18 years ago needed another bypass, because coronary heart disease is unfortunately, always relentlessly progressive despite the best measures we take,” he said in an e-mail interview.
However, those who have gone through surgical interventions to control CAD need not despair, because steps can be taken to prolong life and avoid recurrence of the disease.
In fact, redoing cardiac operations are becoming less common, Dr Jeswant said.
The decline could be due to a few reasons: the use of blood vessels that lasts longer in CABG (arteries rather than veins), better secondary prevention strategies (drugs, lifestyle changes) and the reduction of the need to redo a bypass following the usage of stents (a small metal mesh tube that acts as a scaffold to provide support inside your coronary artery), he added.
Coronary artery disease
This may sound clichéd, but to understand the treatment, we must first understand the disease.
Coronary arteries are blood vessels which channel blood to our heart, supplying it with oxygen and nutrients.
When the coronary arteries are narrowed or blocked, that is when a person has CAD, which leads to ischaemic heart disease (IHD).
The narrowing of coronary arteries may happen due to atherosclerosis (narrowing of arteries due to gradual build-up of cholesterol and other fatty deposits) or the presence of blood clots that block the arteries.
As fatty deposits gradually narrow the arteries, the heart will receive less blood, which means less oxygen and nutrients are transported to the heart muscles.
Eventually, the heart muscles will begin to experience lack of oxygen, and this is when people with CAD experience chest pain (angina), shortness of breath or fatigue.
If left untreated, a complete blockage of the artery can cause a heart attack.
Prevention is better than cure
The prevention of heart disease can be summarised into five simple strategies3:
1. Don’t smoke or use tobacco products
Tobacco smoke contains hazardous chemicals that can damage the heart and its blood vessels, making them more vulnerable to become narrowed.
So, if you are determined to reduce your risk of heart disease, quit smoking.
2. Get active
Regular physical activity can help prevent heart disease by increasing blood flow to your heart and strengthening your heart muscles so that it pumps more blood with less effort.
It also helps reduce your chances of developing risk factors such as high blood pressure, diabetes, high cholesterol and obesity, that can lead to heart disease.
Eating a diet rich in fruits, vegetables, whole grains and low-fat dairy products; limiting your intake of harmful fats; and moderate intake of alcohol can help lower your risk of developing heart disease.
4. Maintain a healthy weight
The association between obesity and heart disease has been established for a long time. Nonetheless, even small weight reductions can be beneficial in reducing the risk of heart disease and stroke.
5. Get regular health screenings
High blood pressure and high cholesterol levels are among the most important risk factors in heart disease. Knowing what your numbers are is important because these conditions often go unnoticed if not tested regularly.
The above description of CAD and its preventive measures have been published so often in pamphlets and in the papers; we may have expected it to have helped raised public awareness about the disease and help them take preventive measures. However, our observations point to the contrary.
“In developing countries like Malaysia, the incidence of coronary heart disease is still rising. This is most likely related to so-called ‘richer’ lifestyle changes,” Dr Quek said.
The changes are seen because Malaysians now eat more fats, meat, and fast foods; exercise less; and prefer a more sedentary lifestyle.
“Most family physicians are advocating preventive measures, but patients often underestimate their value and do not adhere to such measures; for instance, exercise regularly, eat healthily, lose weight, and take preventive medications,” he added.
The treatments of CAD or IHD are largely aimed at relieving symptoms, preventing complications of the disease (heart attacks and heart failures), and improving the quality of a patient’s life, Dr Jeswant explained.
There are two types of treatment: medications to relief symptoms and reduce risk factors; and surgery to improve blood flow to the heart by reconnecting the blood vessels supplying the heart (coronary revascularisation).
Medicines should be the first-line intervention for mild CAD, Dr David said.
The medical therapies involve medications to relief chest pain (anti-anginal medication) or reduce risk factors such as high blood pressure and high cholesterol levels.
“Paying particular attention to the details and understanding what the medicines can do can help one to be more compliant and adherent to these life-long therapies.
“Those with rapidly progressing symptoms, like new heart attacks or near-heart attacks, should present themselves early to the nearest, well-equipped hospital.
“In these people with very high risk, early angiography with revascularisation (angioplasty or bypass surgery) is definitely life-saving and has been shown to reduce the chance of dying by more than 60%,” he stressed.
There are two types of coronary revascularisation: Percutaneous Coronary Interventions (PCI) and Coronary Artery Bypass Grafting (CABG)
Commonly known as coronary angioplasty, PCI is performed by cardiologists to treat narrowed coronary arteries.
By inserting a balloon-tipped tube through an artery in the groin or arm, cardiologists will widen the narrowed artery by inflating the small balloon to push the plaques blocking the artery outward against the artery wall.
A stent is usually inserted in the newly widened part of the artery to hold up the artery as well as lower the risk of the artery returning to its narrowed state.
“Angiography carries a small but finite risk of heart attacks, strokes, vessel damage, kidney damage, as well as radiation dosing,” Dr David said.
It also has a problem of recurrence (restenosis), where the widened blood vessels become narrowed again due to tissue growth or blood clots.
“Restenosis is the bugbear of angioplasty,” Dr David said.
In the past, when only plain balloons were used to widen the coronary arteries, recurrence rates in some arteries were as high as 40-50%.
The use of stents reduced this percentage by half.
Now, with drug-coated stents (drug-eluting stents or medicated stents) restenosis rates have dropped to less than 7-8%, Dr David explained.
More than 90% of patients may have trouble-free periods at least up to four to five years after the medicated stent implant, Dr David said.
However, drug-eluting stents are associated with blood clots and patients have to take long-term dual antiplatelet (blood thinning) medicines such as aspirin and clopidogrel.
On the other hand, “CABG is one of the most common and effective procedures to manage the blockage of blood to the heart muscle,” Dr Jeswant said.
Though many believe that CABG is the last resort when it comes to managing narrowed and blocked arteries, Dr Jeswant said that CABG remains the gold standard for surgical treatment of coronary artery disease.
A CABG (coronary bypass) involves the harvesting of blood vessels from the leg, arm, chest, or abdomen, and connects it to the diseased coronary arteries so that the blood bypasses the blocked area to supply the heart with blood.
What happens to the legs or arms when the blood vessels are harvested?
They will still get their blood supply as we have “dual supply” for those areas, Dr Jeswant said.
As it is a major operation, serious considerations should be made before one decides to go for CABG.
CABG is recommended for people who experience symptomatic debilitating chest pain or are in imminent risk of a heart attack due to CAD.
It is also recommended for people with disease in a few of their coronary arteries, especially so when the left chamber of the heart (left ventricle) is functioning poorly.
Finally, people who have a blocked coronary artery for which angioplasty was unsuccessful or inappropriate due to high risk are also recommended for the procedure.
After CABG, most people experience improvement or complete relief of their symptoms and remain symptom-free for an average of 10 years or more, Dr Jeswant said.
When faced with a choice between angioplasty and CABG, what is the better option? The best bet is to listen to your doctors and always get a second opinion.
“Good judgement as to who and when to balloon or stent (because of unacceptable high risks) is the hallmark of a safe, experienced cardiologist.
“Sometimes a fair and concerned cardiologist would refer to a heart surgeon for bypass surgery because that is the best option, and not because he cannot or is not expert enough to do the procedure,” said Dr David, who went on to note that most doctors have the patient’s long-term interest at heart.
After the procedures, lifestyle modifications such as controlling diabetes and hypertension, diet control, maintaining a healthy lifestyle and ridding bad habits are important steps to improve chances of prolonging survival and delay the recurrence of heart disease, Dr Jeswant said.
Medications such as blood thinners (to prevent blood clot), statins (to lower cholesterol levels) and anti-hypertensives as prescribed are also very important to control the progression of heart disease in a patient who has gone through through CABG or angioplasty.
CABG and angioplasty are palliative treatments, said Dr Jeswant.
That is why patients who have gone through the procedures have to continue taking their medications and lead a healthy lifestyle to prevent recurrence of their disease.
1. Heart Disease: Treatments with Angioplasty and Stents, WebMD; http://www.webmd.com/heart-disease/treatment-angioplasty-stents?page=2
2. Coronary Artery Disease, MayoClinic.com; http://www.mayoclinic.com/health/coronary-artery-disease/DS00064
3. Heart disease prevention: 5 strategies keep your heart healthy, MayoClinic.com; http://www.mayoclinic.com/health/heart-disease-prevention/WO00041
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