Stents Or Bypass: Which Is Safer For Diabetics?

Coronary artery disease is extremely common in adult diabetics. People who have diabetes are from two to eight times more likely to suffer clogged arteries than people of the same age, sex, and race who do not have diabetes. 

Diabetics are also more likely than non-diabetics to have to deal with high cholesterol, high triglycerides, and high blood pressure. Even when diabetics keep one important risk factor in control, for instance, when they manage to maintain normal cholesterol levels, other risk factors take on added significance making heart attack and the need for cardiovascular intervention far greater.

Bypass and Stents in Treating Diabetic Coronary Artery Disease

The two most common interventions for cardiovascular disease manifesting itself as atherosclerosis are coronary artery bypass grafting, more commonly referred to as bypass, and percutaneous coronary intervention, also known as coronary stenting.

In bypass, the surgeon harvests a vein from the leg, cracks open the chest, placing the patient in a heart-lung bypass machine and stopping the heart, and then sewing the vein around the area in which a coronary artery is blocked. Although less invasive versions of bypass exist, the procedure requires several hours under anesthesia and extensive trauma to the midsection of the body. 

In coronary stenting, the surgeon opens a small incision, usually just 3 mm wide, into the femoral artery to run a catheter into the beating heart.

The surgeon then uses the catheter to introduce a metal coil into a segment of a coronary artery that has been damaged or closed by atherosclerosis, expanding the coil to keep the artery open. Stent procedures are performed with local anesthetic where they surgeon makes the incision into the femoral artery, and a sedative to keep the patient from moving around during the procedure. Some patients (including the author of this article) even watch the entire procedure on the doctor's fluoroscope.

Which Is Better for Diabetics, Bypass or Stent?

Cardiovascular surgeons usually prefer stent procedures to bypass. Every year about 350,000 Americans receive bypass surgery, while about 1 million receive stents. Both procedures are extremely expensive, about a quarter of a million dollars for an uncomplicated bypass and between $50,000 and $100,000 for a stent, but patients who receive stents often go home the next or even sometimes the same day, and patients who receive bypass often are in the hospital, or in and out of the hospital, for weeks.

Bypass surgeons in the 1990's typically earned over $1 million per year, but earn about $500,000 per year now. Surgeons specializing in stent placement, however, earn about the same amount.

See Also: Stent Or Bypass: Which Is Better For Treating Heart Disease In Diabetics?

In fact, some surgeons insist on bypass, rather than stents, for almost all their diabetic patients, despite the risks, costs, and length of hospitalization the bypass procedure requires. There are some very clear reasons why.

Why Bypass Is Often Favored For Diabetics

The reality of coronary artery disease in diabetics is that it is harder to control. Repairing one lesion in one coronary artery and then relying on statins, ACE receptor blockers, and beta-blockers to keep more lesions in more arteries from occurring simply doesn't work for most diabetics.

And when they receive five or six stents, which are metal implanted into the lining of an artery to keep it open, future surgical options are limited as doctors run out of places they could place a bypass graft. If a stent fails, the option is usually putting a stent inside a stent, which permanently reduces the flow through the vessel.

Even worse, choosing the wrong kind of stent can have disastrous consequences for a diabetic patient. Older coronary artery stents are made with bare metal, a coil with tiny pores holding a blood vessel open. New coronary artery stents are drug eluting, releasing a medication to prevent the formation of scar tissue.

Diabetics, as you probably know, recover from wounds more slowly than people who do not have diabetes. This is also true of wounds inside their arteries. When artery wall around the stent does not heal quickly enough, sometimes clots can form at the ends of of and along the stent, causing a pseudoaneurysm, a "blowout" of the stent that results in sudden death.

But of that 1%, about 50% die, usually an hour to a week after the operation. When the doctor chooses the wrong anticoagulant, or the patient fails to take anticoagulants as prescribed, clotting and death may also occur.

For all of these reasons, bypass surgery tends to be favored for diabetics. However, bypass surgery carries a great risk of stroke--which is also profoundly disabling and can result in death. There would be tremendous advantage in finding the right kind of stent that doesn't have the risk of clot formation that kills a significant, although small number of diabetics who receive stents every year.

The kind of stent that makes a difference for diabetics, the FREEDOM study at New York University has found, is a cobalt–chromium everolimus-eluting stent, cobalt and chromium the alloy used to make the stent, and everolimus the drug with which it is coated. In their study of 24,015 diabetic patients who received either bypass surgery or stents, they found that:

• Coronary artery bypass surgery is more less likely to result in death of the patient than percutaenous intervention with bare metal stents, or with paclitaxel-eluting stents (Taxus Express, Taxus Liberté, Boston Scientific), which are not widely available in the US, or with sirolimus-eluting stents (Cypher, Cypher Select, Cypher Select Plus, Cordis), not all of which are always available.
• Stent procedures are not more likely to result in death when the surgeon uses the previously mentioned cobalt–chromium everolimus-eluting stent or a the zotarolimus-eluting stents (Endeavor, Endeavor Resolute, Endeavor Sprint, Medtronic), or the platinum–chromium everolimus-eluting stents (Promus, Promus Element, Boston Scientific). 

See Also: DIGAMi 1: New Study Says Diabetics Need Insulin, Not Pills, To Recover From Heart Attacks

You don't want to be lying on the surgical table when your doctor tells the surgical nurse, give me the cheap one--which is exactly what happened to me, and I had a cardiac arrest in the recovery room. If you have diabetes, ask your doctor whether or not receiving drug-eluting stents, and ask for a second opinion if the answer is no.