| Stents have reduced the need for bypass surgery to 1 per cent
The poets and songwriters deduced it correctly; the ultimate irrevocable act of love is giving your heart to someone else. The heart is the fulcrum on which the pendulum of life swings. Its continued non-stop, efficient, self-regulating pumping action supplies essential oxygen to all the tissues of the body. It looks rather unromantic though — it is made of muscle and is the size of a clenched fist. It is nurtured and oxygenated by the coronary arteries which snake over its surface.
At birth we have open, pliant coronary arteries, but a lifetime of abuse with a sedentary lifestyle, smoking, an unhealthy diet and obesity takes its toll. Fat deposits form plaques on the arterial walls making them irregular, narrow and stiff, eventually blocking them. The blood supply to the muscles of the heart is then compromised, causing ischemia with chest pain, sweating and a feeling of impending doom — the characteristic symptoms of angina. Heart disease is more likely to occur in diabetics, people with high blood pressure, smokers and those with elevated abnormal lipid profiles. The first attack can be fatal in 50 per cent of the people in the first two hours if they do not receive adequate emergency intervention.
Angina is the classic precursor to a heart attack. The pain can occur at night, or be precipitated by varying degrees of activity. It can initially be managed with medication like glyceryl trinitrate, sorbitrates, calcium channel blockers and clot-preventing medication like aspirin or clopidogrel. If you go to a cardiologist, he may opt for a coronary angiogram to outline the blood supply to the heart. This is performed by inserting a thin tube through an artery in the arm or leg and then guiding it into the heart. A dye is then injected, so that the arteries can be seen.
A catheter is inserted into a larger artery, usually the femoral artery in the groin. It has a tip called a balloon which can be dilated. This opens up the narrowed vessel and also pushes through the clot, dispersing it. This procedure can minimise or stop a heart attack if performed in time. This technique was first used in 1977. The results were not very encouraging. Restenosis (narrowing of the arterial walls once again) occurred in 30-40 per cent of the people within six months of the process. The procedure and technique have improved vastly in the last 30 years. Metal stents can now be inserted through the balloons. These are coiled springs which open up when released from the balloon. They function as a scaffold and hold the coronary vessel open. The bare metal stents reduce the risk of restenosis to less than 20 per cent.
Newer drug eluting stents — or medicated stents that slowly release their contents — are available. They are far more expensive, costing anything between Rs 70,000 and Rs 3.5 lakh, depending upon various factors such as the make of the stent, doctors fee, hospital charges, etc. There is still debate as to whether they are really worth the expense. At present the three major drugs present in the various stents are: paclitaxel, sirolimus or a drug called ABT580, depending on the manufacturer. Although each company claims that its stent is the best, they are all equally effective. The particular one used depends on the individual preference of the cardiologist. Restenosis occurs in less than 10 per cent of patients.
Stents once inserted cannot be removed. If blockage occurs in another part of the artery a new stent has to be placed there. The expertise of the cardiologist is necessary to estimate the size of the block and the vessel, choose a stent of the correct size, and insert it in the proper place. If any of these parameters are miscalculated there will be leaks, restenosis and inefficiency. The stents (drug eluting or bare metal) have reduced the need for bypass surgery to 1 per cent. Bypass surgery is still required in complicated cases especially when the left coronary artery is involved.
Survival after a heart attack before 1967 meant a lifetime of medication, restricted activity and a Damocles sword of sudden death. This scenario changed when the first Coronary Artery Bypass Graft (CABG) surgery was performed in Cleveland Clinic in the US in the late 1960s. It became possible to surgically bypass the blocked, narrowed and inefficient areas of the coronary blood vessels, using the saphenous vein from the leg or the internal mammary artery from the chest wall. Depending on the number of blocks and the expertise of the surgical team, two, three, four and even five blocks can be bypassed.
The heart may have to be stopped and the entire circulation supported during the time of surgery with a heart lung machine. Today, surgical techniques have advanced, and minimally invasive CABG can be performed without stopping the heart.
Stents are not a miracle cure. For the best long-term results, patients still need to
• Control diabetes and hypertension
• Achieve their ideal body weight
• Continue their anticlotting medication of aspirin and clopidogrel.
Dr Gita Mathai is a paediatrician with a family practice at Vellore. Questions on health issues may be emailed to her at firstname.lastname@example.org