Part 2: I Had a Stent. How Long Do I Keep Taking Blood Thinners?
My 'ask your doctor' series provides answers to common patient questions.
[Note: Wherever possible I embed links (hover your pointer over colored words) to high quality cardiology websites and original medical publications so you can read further about topics I discuss.]
Most stents that interventional cardiologists use to open your coronary artery blockage are known as DES or drug eluting stents. Cardiologists have used simple balloons, non-coated (bare metal) stents and over the past decade drug eluting stents.
The problem with angioplasty (refers to opening of a blockage) is that the simple process of inflating a balloon within the blood vessel, actually causes vessel injury/irritation. The blood vessel can react in one of two ways. Either it heals ‘open’…or it narrows. The re-narrowing of a blood vessel after angioplasty is known as in-stent restenosis. Restenosis is not more cholesterol accumulating in the artery, but an overgrowth of tissue of the blood vessel. We call this intimal hyperplasia which causes the in-stent restenosis describd above. A good analogy is a keloid scar after surgery: some people heal nicely and others develop a keloid.
Drug eluting stents, DES, prevent restenosis effectively because of the medication embedded on the stent itself. The medication is mixed with a polymer that is bound to the stent. The medications have difficult names such as Zotarolimus, everolimus, and ridaforolimus. The stents are made of quite fancy materials. The polymer is designed to release the medication over a set period of time.
Following a drug eluting stent, it is recommended to continue dual antiplatelet therapy DAPT (aspirin plus another blood thinner called a PGY12 plated receptor inhibitor) for 6-12 months. This is intended to prevent subacute thrombosis: a devastating condition that results in a stent clotting due to exposed metal struts in your blood stream. Subacuate thrombosis is not restenosis. SAT refers to an actual clot forming in the blood vessel identical to a heart attack.
Cardiologists use the term DAPT or dual antiplatelet therapy. Dual refers to the use of two medications. One is aspirin the other is a class of medications known as PGY12 platelet receptor inhibitors.
1. Aspirin is prescribed life long and the PGY12 inhibitor is prescribed for 12 months.
2. PGY12 platelet inhibitors:
What is being challenged is the ’12 month’ requirement of DAPT. Several studies have demonstrated the possibility of reducing the duration of using both aspirin and PGY12 inhibitors. STOPDAPT-2; SMART-CHOICE.
Because the newer stents cause less trauma to the blood vessel, it is often possible to stop DAPT in 6 months to avoid bleeding risk. However, a lot depends upon the complexity of the stent procedure, size of the blood vessel, number of stents. In other words, your cardiologist will advise you when to stop DAPT and continue aspirin depending upon your particular situation.
Always discuss with your cardiologist how long to use DAPT (dual antiplatelet therapy). For my patients, I will continue DAPT for 12 months. Following this, the PGY12 inhibitor is stopped and the aspirin is continued lifelong. However, it may be possible to stop DAPT < 6 months on certain low risk patients to avoid bleeding risks.
Note: Understanding your heart condition is not difficult. Patients become frustrated and confused when doctors don’t explain things clearly. If you don’t understand what your doctor is talking about, then you won’t be able to ask meaningful questions. I hope that my posts provide you with a framework that you can build upon to become an active participant in your healthcare.
Gregg M. Yamada MD FACC
Disclaimer: I hope you find my medical blogs to be pertinent, interesting, thought provoking, and even humorous. The information provided is educational and should not be taken as medical advice. I am a doctor, but I am not your doctor. Please schedule an appointment with your doctor to discuss these issues and to determine what is right for you.
© 2019. Gregg M. Yamada, MD FACC. All rights reserved