More than half a million Americans in 2009 had a hospital stay that included the placement of a stent. But what is stent placement, who is it for, and do the risks outweigh the benefits?
When Do Patients Receive Stents
Patients often receive a stent during or immediately after a procedure called angioplasty. Angioplasty is performed in patients with narrowed or blocked blood vessels, which prevent blood from reaching the heart. In angioplasty, a small tube called a catheter with a balloon on the end travels through a blood vessel to the artery with the blockage. Once the catheter reaches its destination, the doctor will inflate the balloon to help send the plaque causing the blockage out against the wall of the artery, allowing blood to flow normally.
What is a Stent?
A stent is a tube that opens the artery and, ideally, keeps it open for the long-term. They are normally made of a metal mesh material but can be made of fabric. Fabric stents are more commonly used when treating larger arteries.
If a stent is used during angioplasty, it is placed around the deflated balloon. When the doctor inflates the balloon, the stent expands to keep the passageway open. The balloon and catheter removed, but the stent remains, becoming part of the once-blocked artery. In severe blockages, this may be a multistep process, starting with a smaller balloon and then using a larger one.
Stent placement in cases of aortic aneurysms are similar, but the stent itself may be different, and the procedure is usually longer. In these cases, the stent may be made of fabric and have at least one small hook on it. The stent tightly fits on the artery and the hook or hooks catch on to the artery walls.
In both scenarios, cells will eventually grow to cover the stent, and the blood vessel will look normal again overtime.
Types of Stents
There are two types of stents: drug-eluting stents and bare metal stents. Drug-eluting stents are coated with medicine that is continuously released into the artery long after the stent placement is over, with the goal of hopefully preventing the artery from becoming clogged again. Bare metal stents do not have any drug coating. Patients with a high risk for bleeding may be better candidates for bare metal stents. Drug-eluting stent patients may be prescribed long-term antiplatelet medication after the procedure.
Is It Safe?
Like most procedures, angioplasty and stent placement come with potential risks. These may include:
- Bleeding or infection at the catheter insertion site
- Blood clot/blood vessel damage
- Abnormal heart rhythms
- Heart attack
- Chest pain/discomfort
- Rupture or closing of the coronary artery
- Allergic reaction to/kidney damage from contrast dye
It’s also possible that the artery will reclose after angioplasty—this is called restenosis and occurs in about a third of patients who undergo angioplasty without a stent. In the event that the artery still closes even with a stent, a patient may have to undergo coronary artery bypass surgery (CABG).
Care After Angioplasty
After the procedure, patients will be prescribed at least one antiplatelet medication, which will help prevent platelets from clumping and forming blood clots, which could otherwise block the artery again.
Antiplatelet agents include aspirin and a P2Y12 inhibitor. Based on the patient’s unique profile, a doctor may prescribe one of three P2Y12 inhibitors: clopidogrel, prasugrel, or ticagrelor. Using a P2Y12 inhibitor in combination with aspirin is called dual antiplatelet therapy (DAPT).
Patients with a history of heart attack should be prescribed a P2Y12 inhibitor for at least a year; longer duration could help reduce the risk of future heart attack. Patients with high bleeding risk may have received a bare metal stent and could be prescribed a P2Y12 inhibitor for at least a month. Patients who received a drug-eluting stent could be on a P2Y12 inhibitor from six months to one year; high-risk bleeding patients could have shorter courses of treatment, while those who do not have a significant bleeding risk may be treated for longer than a year.
Stents: Good for Everyone, And for How Long?
Some research has suggested that the perceived benefits of stents may outweigh the reality. A 2006 study published in The American Journal of Cardiology found no difference in mortality rates between patients who underwent angioplasty alone versus revascularization with coronary stents. The researchers evaluated data from the Duke Database for Cardiovascular Disease on 1,288 patients who underwent revascularization with angioplasty alone or stent placement between 1990 and 1992. Assessed outcomes included outcomes of death, myocardial infarction, and repeat target vessel revascularization (TVR).
“At a median follow-up of 7 years, although treatment with coronary stenting was associated with a significant and sustained decrease in repeat [target vessel revascularization] (TVR) (18.0% vs 28.1%, P=0.0002) and the occurrence of death, myocardial infarction or TVR (39.2% vs 45.8%, P=0.004), long-term survival did not significantly differ between treatment groups (19.9% vs 20.5%, P=0.72),” wrote the researchers. “Outcomes of death and myocardial infarction did not significantly differ between patients who did and did not undergo repeat TVR.”