KNOWING ABOUT ANGIOPLASTY & STENTS

As we are an ageing population, more and more Sri Lankans will be afflicted by this dreaded disease- coronary artery blockage.

The earlier ones acquires knowledge, and prepares for it by reading these articles, is a sensible move, and stands to good reason.

Most of us, in spite of even after regular exercises, diet control, keeping a regulated body weight, frequent medical check ups, etc. can suffer with heart related angina pain in the chest. Obviously, with mild pain in the chest one would brush it off, thinking it could be muscular in origin. If the pain persists one may need to get prompt professional assistance.

The typical beneath the sternum (substernal) constricting pain radiating down the inner side of the left arm, as described in text books is not the typical pain experienced by most people. I know of a surgeon at the age of 70 who was complaining of tiredness at the end of the day, and all his cardiac physician colleagues attributed it to 'old age'. This surgeon, not satisfied, flew to Madras, met one of the known cardiac physicians, and complained about his tiredness. Prompt cardiac studies were carried out, including an angiogram. The latter revealed a four vessel block, and next day he was subjected to open heart surgery. He lived afterwards a good working life for nearly three years but after a massive heart attack whilst swimming, died within few hours.

The coronary arteries supply a constant flow of oxygen-rich blood to the heart, which pumps almost 2,000 gallons of blood throughout the body each day. If plaques builds up in these arteries, blockages can develop, reducing blood flow to the heart, causing symptoms ranging from tiredness to severe symptoms, which can be fatal.

Angioplasty

The current thoughts are that coronary angioplasty, sometimes called PTCA or PCI, (percutaneous coronary intervention), is a catheter based method performed by an interventional cardiologist in order to open a blocked coronary artery to restore the blood supply to the heart. This intervention as we call angioplasty is considered a noninvasive choice, if one to two arteries are blocked, and open heart surgery would be preferred if more vessels are affected.

Some cardiologists have unblocked more vessels by this technique, on good risk younger patients. One disadvantage of this technique has been that 20%-30% of the time, the artery closes up again within six months. To prevent such closure, during the past few years drug-eluting stents have become available. They have been shown to reduce this rate, making PCI much more successful over time.

With more practical experience these cardiologists now perform angioplasty as an emergency procedure to dislodge the blockage in coronary arteries.

It is advisable today to enter a cardiac center the moment you experience chest pain, without waiting. As soon as you enter hospital, with symptoms of chest pain, a medical history is taken by the medical officer, assessment of risk factors is made, and a number of non-invasive tests will be performed.

If a blocked coronary artery is suspected, a thallium stress test is usually performed. If this test is non-conclusive, then a cardiac catheterization is scheduled.

Cardiac catheterization is the "gold standard" for the diagnosis of coronary artery block.

If the catheterization clearly reveals the coronary blockage, the treatment procedure can be done without wasting further time.

Angioplasty procedure (Angiogram)

A local anaesthetic is injected into the patient's groin, arm or hand. A puncture is then made, and the cardiologist threads a very thin soft tipped guide wire and catheter through the entry site and, while watching on the fluoroscope video screen, follows the main artery in the body, called the aorta, up and around into the opening of the left or right coronary artery. The patient at this stage may feel uncomfortable when the needle is first inserted.

The cardiologist injects a special dye, which reveals any obstruction or plaques located within the coronary arteries. Patients may feel warm on injection of the dye.

If a blockage is noted, the cardiologist threads a thin wire across the area of the blockage. A 'rail-road' track into the coronary artery has now been established, and a tiny balloon is passed over the wire and positioned precisely at the obstruction. Now the balloon is inflated to expand the coronary vessel and the blockage is opened. Balloon is then withdrawn. Next step - a stent is inserted and remains in position as a scaffolding for the newly widened artery. Today, the immediate risk factors following angiography, is less than 1%.

When the procedure is over all equipment is removed and the puncture site is compressed with dressing to prevent blood leakage. The patient is now observed in an Intensive Care Unit and discharged in a day or two, if uneventful.

One problem with after angioplasty is re-stenosis or closure of the artery within six months. On the other hand bypass surgery is more extensive, time consuming, longer stay in hospital, with more day to day after care risks, but lives ultimately with a better quality of life.

Dr John Spertus, M.D.,M.P.H. director of cardiovascular education at the Mid-America Heart Institute in Kansas City, Mo states, previous studies comparing the two approaches have shown that people's health status is better, on average, after bypass surgery.

He further said, "We found that patients at intermediate and high risk of re-stenosis are far more likely to get more benefits from bypass surgery while those at lower risk will do fine without undergoing major surgery."

In bypass surgery the blood is bypassed through a graft tube, either an artery or through a segment of vein from the leg, from the same person (auto graft), around the blocked vessel to improve the circulation to the heart muscle beyond the blockage. This procedure does not suit those who suffer from a dead inactive area of heart muscle (infarct), following blockage of a major coronary vessel, especially in high risk patients. Conservative regime is the only alternative therapy suited for them.

Angioplasty is a much simpler non-surgical intervention where a wire mesh tube called a stent is placed at the site of blockage by inflating the blocked artery, pushing plaques to the side, through an inflatable balloon. Bypass surgery patients stay in hospital for at least five days, and have to be extremely careful recuperating for another six weeks, whilst after angioplasty the patient goes home next day and has to be careful for a few days.

Both procedures improve the blood circulation beyond the blockage and the heart related chest pain is minimized

In terms of cost factor, the patient goes home with a similar bill by either procedure. The catheters used and the imported stents from Germany or U.S. are exorbitantly priced. The U.S stent is almost double the cost.

Stents- that release medication

It is observed that coronary artery stents that release a medication appears to result in better outcomes than traditional stents for heart patients, according to a study in the May 4 issue of JAMA.

Sirolimus, a substance that is thought to help prevent re-closure of coronary arteries, was used in certain types of stents which prevents restenosis compared to stents without the chemical, according to the newsletter 'Medical News Today' (5/9/2005). These drug eluting stents have the potential to improve long term clinical outcome after primary percutaneous coronary intervention (PCI), such as angioplasty.

Due to the hiked prices on sirolimus eluting stents, the drug abciximab was recommended. According to the current European list prices, the use of the drug tirofiban is recommended instead of abciximab.

It is observed that drug-eluting stents may be superior to the traditional bare-metal stents in use.

Now let's talk about the American experience.

Dateline September 30, 2002, Richard N. Fogoros, MD, reports the results of two large trials using drug coated stents. He states that with drug-coated stents the risk of restenosis (the largest remaining problem with the use of stents in coronary arteries) appears to be dramatically reduced.

The first of the two trials, the SIRIUS trial, examined the use of the sirolimus-coated stent. Previous trials with this stent suggested a remarkable reduction in restenosis compared to using bare metal stents. However, the earlier trials were largely limited to patients whose coronary artery blockages were considered nearly ideal for the use of stents. In the SIRIUS trial, in contrast, patients were intentionally enrolled whose blockages were considered high risk. Despite the higher risk population of patients, the SIRIUS trial showed a pronounced reduction in the rate of restenosis among patients receiving the sirolimus-coated stents.

In the second trial, TAXUS 11, results with a paclitaxel-coated stent from Boston Scientific were presented. Overall results were comparable to those achieved with the sirolimus-coated stents. The cost of these new stents approximates $3000 per piece, compared to approximately $ 1000 for standard stents.

It is also reported in the May 4 JAMA 2003, "real world" use of drug-releasing coronary artery stents reveal higher rates of stent thrombosis (blood clots) 9 months after stent implantation than were indicated in clinical trials.

Loannis Lakovou, M.D., of the Centro Curore Columbus and San Raffaela Hospital, Milan, and colleagues report that in a study at 3 hospitals in Germany and Italy, a total of 1,062 patients underwent successful implantation of sirolimus eluting stents, and 1,167 had a drug paclitaxel-eluting stents between April 2002 and January 2004.

At 9 month follow up, 29 patients had stent thrombosis (blood clot formation) with sirolimus and 20 with paclitaxel eluting stents.

Some of these patients with both kinds of chemicals eluting stents experienced nonfatal heart attacks, kidney failure, and diabetes.

So it is observed that drug-releasing stents showed higher complications rate much more than clinically expected.

Another disappointing result, life after angioplasty was presented in Nov 08, 2004, after a trial by Duke University's David Kandzari, MD, and his colleagues. The findings come from a study of patients who underwent balloon angioplasty between 1990 and 2002. These results may help doctors decide whether to treat patients with balloon angioplasty or with much more invasive heart bypass surgery.

Out of some 12,000 patient records from 1990-2002, Kandzari and colleagues found 644 pairs of closely matched balloon angioplasty students. One member of each patient pair received a stent during the balloon angioplasty; the other treated before the advent of stents - 1994, didn't.

The findings were that patients who got stents had fewer repeat angioplasties. But after seven years of follow-up, those who got stents didn't survive any longer than those who did not get them.

"Whilst stenting was associated with significant reduction in the need for repeat procedures, it made absolutely no difference in long term mortality," stated Kandzari. Both groups had 20% mortality over 7 years. This reminds us that stents, as used in the real world, are not associated with a survival advantage.

Prediman K.Shah, MD, at Cedara-Sinai Medical Centre, in LA, and professor of cardiology at UCLA states that stents save the lives of heart attack or unstable angina patients when they are used to open the blockage causing acute problems. For some patients, Shah says, bypass surgery may offer a survival advantage over balloon angioplasty with stents. However, balloon angioplasty is far less risky for some patients with heart disease and less invasive than bypass surgery.

Bypass surgery - in selected subgroups of patients - does reduce mortality because bypassing creates an alternate source of blood flow, states Shah.

Kandzari makes a similar point. He states, "Doctors often exclude other therapies in favour of stents alone. There is more to patients' treatment than just putting them on stents."

Aggressive medical treatment-use of statins, tight diabetic control, caring about body weight, and lifestyle changes are very important to patient survival, Kandzari and Shah agree.

Problems, Problems and Problems!!

Richard N.Fogoros MD in Dateline July 30 2003 reports, "The CYPHER drug-coated stent (J&J), has made a huge impact in the treatment of coronary artery disease since it was first approved for marketing in April, 2003." Over 50,000 of these stents have been used in patients during the first 3 months following approval. The major advantage, Fogoros says of the stent is that it greatly reduces the incidence of restenosis, i.e occlusion of the artery where it was lodged.

In July 2003, however, the manufacturer J&J was compelled to send a "Dear Colleague" letter to doctors across the US, warning of a risk of clotting of the CYPHER stents within a few days of implantation.
Another fresh report came out from Richard N.Fogoros - Dateline Nov.30.2003, stating that the previous warnings on Cypher drug coated stents were false alarms. Same month the FDA released the latest data on the drug coated Cypher stent, that the incidence of restenosis due to thrombosis is no higher with this stent than expected.
Discuss the brand and the type of stent the cardiologist will use before hand, if it is indicated.

Those readers who have undergone stent surgery will wonder what the future prognosis would be for them. It is very important that they immediately contact the cardiologist if any pain, shortness of breath or other symptoms develop after stent angioplasty. The patient must regularly take the prescribed medication by the cardiologist. The first six months after angioplasty is most important because it is during this period that restenosis will occur. The cardiologist will recommend low dose aspirin or any other blood thining medication for the rest of the life. Aspirin prevents stickiness of platelets and maintain the blood thin, thereby preventing blood clotting.
They must stick to a lifestyle that will eliminate all risk factors. For those readers who have so far been lucky, too should avoid all risk factors. Check your blood pressure, sugar levels regularly. Stay within the body weight after checking from the BMI chart. Avoid fatty food, excess carbohydrates, salt and processed food, including precooked food with trans-fat. Limit drinking alcohol to one glass a day, preferably red wine, considered as good as aspirin. You must go to a gym at least three times a week for a cardiac work out. Do not indulge in body building routines, as it will increase your blood pressure. If you do not wish to live a lifestyle compatible the with above factors, do save at least over Rs. 500,000.00 to pay private hospital bills. The drug coated stent alone will cost you Rs. 250,000 or more. So, stay healthy and live longer. There is no other way to live. (The author was a Senior Registrar in the Cardio-thoracic Unit in Singapore in the seventies). Ref: Drug Coated Scents Are Looking Good- From Richard F;jgorr) s Angioplasty 101 org. (5/10/2005) Medical News Today (5/9/2005) www.americamheart.org (5/10/2005) Scents May Not Increase Patient Survival, by Daniel DeNoon-http://my.webmd.com Problems with the Drug-coated stent- from Richard N Fogoros, Dateline 07/30/03
