Dissolving heart stent debuts at Emanuel Medical Center in Turlock

Dr. Ali Reza implanted a heart stent in a patient last month that will perform a disappearing act after the artery is healed.

The procedure was done at Turlock’s Emanuel Medical Center, one of the first hospitals to use what could be the next generation of stents to treat heart disease. Emanuel’s recent announcement has already sparked debate over how widely the stents will be used at hospitals in the region.

Approved by the Food and Drug Administration in July, the dissolving stent placed in a diseased coronary artery is absorbed by the body over three years, and reduces the chances of further blockage that can cause a heart attack, Emanuel said.

The Absorb stent, developed by Abbott Vascular, is made of a biodegradable polymer similar to the material in dissolving sutures. Physicians hope it is an improvement over traditional metal stents, which sometimes cause scar tissue that narrows the artery, requiring another heart procedure.

Metal hardware left inside coronary arteries also may complicate matters for a surgeon if a patient later needs bypass surgery, physicians said.

Stents, or small metal scaffolds, are used in angioplasty procedures to widen coronary blood vessels partly blocked by fatty deposits. People needing the treatment often have chest pain, shortness of breath and other effects of heart disease, which results in 370,000 deaths each year in the United States.

Historically, doctors first threaded a lead through an incision in the groin and inflated a balloon to open coronary blood vessels, but artery walls would collapse after the balloon was removed. Metallic stents were developed to keep arteries open, and newer versions were coated with a drug to prevent scar tissue from forming. Now, dissolvable stents are making sense.

“The issue with metal stents is that after a blockage in a blood vessel is cleared, it only needs support for a matter of months until the vessel heals and can stay open on its own,” Reza explained. “After that, the metallic stent serves no additional purpose, and can, in fact, be a hindrance.”

Emanuel was the first hospital in the San Joaquin Valley between Sacramento and Fresno to start using Absorb stents.

Not for smaller blood vessels

The FDA approved Absorb with precautions not to place it in smaller blood vessels due to risk of blood clots. In a one-year trial involving 2,008 patients, the rate of heart-related complications in patients implanted with the dissolving stent was 7.8 percent, compared with 6.1 percent in a group that received a drug-eluting (which means drug-releasing) metal stent also made by Abbott.

The FDA said the difference was not statistically significant. The rate of blood clots with the Absorb stent was 1.54 percent and 0.74 percent with the metal stent. Heart patients are advised to talk with their doctor about the appropriate stent or treatment for their condition.

Physicians at Emanuel are not dismissing metallic stents – they will still be used for many patients.

Dr. Reza Nazari, an interventional cardiologist at Emanuel, said guidelines call for placing Absorb in larger arteries that are not overly calcified. During the one- to two-hour procedure, Nazari looks through a small camera to make sure the vessel is the proper size or larger than 2.5 millimeters in diameter.

Dr. Oussama Dagher, director of cardiovascular services at Emanuel, said a “re-stenosis” or narrowing of the artery can occur with metallic stents, requiring a second procedure that may place metal on metal. Dagher said he has implanted the dissolving stent in two patients thus far. Both were discharged from the hospital and “so far, so good,” he said.

The dissolving stent was approved for use in Europe five years ago and more than 150,000 people have been treated with it in various countries.

“It has great potential,” Dagher said. “You need to have the right patient with the right vessel size. I believe they will fine-tune the technology more and it will replace the current stents.”

Following FDA approval in July, Abbott first made the new device available at hospitals that participated in the clinical trial and has begun training doctors at other centers in the precise technique for implanting the stents.

The development comes as the National Heart, Lung and Blood Institute conducts a clinical trial that could tell whether medical therapy versus stenting is more effective in treating people with chest pain.

At Emanuel, patients are recommended for the catheterization lab and possible stenting if they have angina, fail a stress test and are not responding to treatment with medication, Nazari said.

Experts comment

Dr. Jeffrey Southard, associate professor with the UC Davis Division of Cardiovascular Medicine, said the next year should provide more information on how patients are faring with dissolving stents.

Southard, who was involved with the clinical trial, said about 20 percent of patients meet the guidelines for the device. Patients who receive the stent have to take aspirin and a second blood thinner for a year.

The dissolving stent is slightly thicker and less flexible than the metal ones, Southard said. “As the second or third generation of these devices come out, they could be used in a broader array of patients and could become the standard of care,” he said.

Doctors Medical Center of Modesto said the dissolving stents are not used at the hospital on Florida Avenue, but it plans to add the “promising technology to the many offerings in our cardiac program.” Doctors and Emanuel have the same parent company.

Memorial Medical Center will take a careful approach with the new device.

Sutter Gould medical group and Memorial enrolled patients in one of the major clinical trials for the device. “We are monitoring the long-term results of the trials, as well as the results from patients receiving this treatment from our Sutter Health colleagues in Sacramento and San Francisco,” said Dr. Peter Lai, the senior interventional cardiologist at Sutter Gould in Modesto. “We anticipate adopting usage of this device in the near future for appropriate patients.”

Dr. David Roberts, the primary investigator for the Absorb trial at Sutter Medical Center in Sacramento, said the new device should be used with caution. He sees this early version as a niche device to clear large arteries or serve other selected purposes.

Perfected over 20 years, metallic stents are still an outstanding technology, said Roberts, who believes concern about leaving them in arteries is overblown. “The results with coronary stenting, when used appropriately, are excellent,” Roberts said. The risk of clotting with metallic stents is less than 1 percent and narrowing of the artery occurs in less than 5 percent of cases, he noted.

Roberts said that studies comparing Absorb with the metallic stent showed an equivalent level of safety, but the risk of clotting and heart attacks were slightly higher with the dissolving stent and were higher when Absorb was placed in smaller blood vessels.

Abbott said for competitive reasons it does not disclose the price for Absorb. The cost may differ under contracts with various hospitals, and Absorb is in the same reimbursement category as drug-eluting stents, a spokeswoman said.

The stent is not recommended for patients who are allergic to materials in the device, sensitive to the contrast agent used in angioplasty, or cannot tolerate aspirin along with other blood-thinning drugs, the FDA said.

This story was originally published November 17, 2016 at 6:27 PM with the headline "Dissolving heart stent debuts at Emanuel Medical Center in Turlock."