Do I need to stop aspirin before an angiogram?

October 11, 2025 •

4 min read

According to the American College of Cardiology and American Heart Association, aspirin use before angioplasty is a Class I recommendation. The vast majority of patients scheduled for a diagnostic coronary angiogram should not stop aspirin before the procedure and, in many cases, are instructed to take their regular dose on the morning of the procedure.

Quick Summary

This article clarifies standard medical guidelines regarding aspirin use before an angiogram. For most patients, continuing aspirin is safer than stopping it due to the balance between bleeding risk and the higher risk of blood clots. Always follow your specific pre-procedure instructions.

Key Points

Do not stop aspirin: For most angiograms, especially if a stent is a possibility, you should continue taking your daily aspirin dose as instructed by your doctor.
Risk of stopping: Prematurely stopping aspirin can significantly increase your risk of heart attack or stroke, particularly if you have recently had a coronary stent placed.
Benefits outweigh risk: The risk of minor bleeding associated with continuing aspirin for a low-to-moderate risk procedure like an angiogram is considered less dangerous than the risk of blood clots.
Discuss with your doctor: Always confirm your specific pre-procedure medication instructions with your cardiologist or medical team to ensure the plan is tailored to your health history.
Different for other medications: Other blood thinners, such as warfarin or newer anticoagulants, and certain other antiplatelet drugs (P2Y12 inhibitors) typically require temporary discontinuation, unlike aspirin.

The General Rule: Continue Aspirin for Most Angiograms

For most diagnostic coronary angiograms (also known as a cardiac catheterization), the standard instruction from cardiologists is to continue taking your prescribed dose of aspirin. This may seem counterintuitive since aspirin is a blood thinner, but the benefits of preventing blood clots during the procedure generally outweigh the risk of increased bleeding. Patients on aspirin are typically instructed to take their medication as usual, including on the day of the procedure, often with just a small sip of water.

This advice is particularly critical because an angiogram can sometimes be converted into a percutaneous coronary intervention (PCI), or angioplasty and stenting, if significant blockages are discovered. In this scenario, the antiplatelet effects of aspirin are vital for preventing serious complications like stent thrombosis, where a blood clot forms inside the newly placed stent.

Balancing Bleeding Risk vs. Thrombotic Risk

Deciding whether to continue or stop antiplatelet medication like aspirin is a complex clinical judgment that balances two primary risks: bleeding and thrombosis (clot formation).

The Dangers of Thrombotic Risk

Platelets are tiny blood cells that help your body form clots to stop bleeding. Aspirin works by making platelets less sticky, reducing the risk of unwanted clot formation in your arteries that can lead to a heart attack or stroke. When you have coronary artery disease (CAD), this is a critical defense mechanism. For patients with recently placed coronary stents, the risk of prematurely stopping antiplatelet therapy is significant. Studies have shown that abrupt withdrawal can increase cardiovascular risk by threefold. This risk is so serious that some guidelines recommend continuing dual antiplatelet therapy (DAPT) for extended periods after stent placement. The trauma to the vessel wall from the angiogram or stenting procedure itself makes the area prone to clotting, so maintaining the antiplatelet effect is a key safety measure.

The Manageable Bleeding Risk

The bleeding risk associated with continuing aspirin for a standard angiogram is considered low-to-moderate and is typically manageable. During the procedure, a catheter is inserted through a blood vessel, usually in the wrist or groin. While some minor bruising or a small hematoma (a collection of blood under the skin) may occur at the access site, this is a much lower risk event than a heart attack or stroke caused by a clot. Modern techniques, such as using the radial artery in the wrist, have further reduced bleeding complications. For low-risk invasive procedures, continuing aspirin leads to only a modest increase in bleeding complications and typically doesn't increase the severity of bleeding.

Exceptions and Specific Scenarios

While the advice to continue aspirin covers most cases, certain circumstances may require different instructions. It is crucial to have a detailed conversation with your cardiologist or surgical team about your complete medication list and health history.

Here are a few important considerations:

High Bleeding Risk: For surgical procedures with an inherently high bleeding risk (e.g., neurosurgery or some spinal procedures), discontinuing aspirin may be necessary. For these specific, rare cases related to angiography, the medication might be stopped about five days beforehand to allow the effect on platelets to wear off.
Dual Antiplatelet Therapy (DAPT): If you are on DAPT, which includes aspirin and another antiplatelet agent like clopidogrel (Plavix), ticagrelor (Brilinta), or prasugrel (Effient), specific instructions will be provided. In many cases, you will be told to continue both medications. However, in some situations, particularly after recent stent placement, a P2Y12 inhibitor might be stopped temporarily while aspirin is continued.
Other Anticoagulants: Medications that act differently than aspirin, such as warfarin (Coumadin) or the newer direct oral anticoagulants (DOACs) like dabigatran (Pradaxa) and apixaban (Eliquis), typically must be stopped several days before the procedure. Always follow the specific instructions for these potent blood thinners.
History of Bleeding Disorders: Patients with a known history of bleeding disorders, such as hemophilia, or those with active stomach or intestinal ulcers may be advised to manage their aspirin differently.

Comparison of Aspirin Management Before Angiogram


Aspect	Continuing Aspirin (Standard Practice)	Stopping Aspirin (Rarely for Angiogram)
Primary Goal	Prevent life-threatening clots (thrombosis).	Minimize procedure-related bleeding risk.
Thrombotic Risk	Significantly lower risk of heart attack, stroke, or stent thrombosis.	Increased risk, especially with recent stents or CAD history.
Bleeding Risk	Slightly increased risk of minor bruising or hematoma at the catheter site.	Decreased risk of minor bleeding, but higher risk of dangerous clots.
Standard Angiogram	Recommended. Benefits of preventing clots outweigh the risks of minor bleeding.	Not Recommended. Risk of thrombosis is too high for most patients.
Timing	Take as scheduled, including morning of the procedure.	Typically stopped 5-7 days prior, but only for high bleeding risk surgery.

Always Talk to Your Care Team

The most critical step is to follow the instructions provided by your specific medical team. Your cardiologist, surgeon, or pre-assessment nurse will give you precise guidance tailored to your health status, medication list, and the details of your procedure. Do not make any changes to your medication schedule without explicit medical advice.

Conclusion

In the vast majority of cases, the answer to the question "Do I need to stop aspirin before an angiogram?" is no. Continuing aspirin is the standard of care for most patients undergoing this procedure to minimize the risk of serious thrombotic complications like heart attack and stroke. The decision hinges on a careful balance of a patient's individual bleeding and clotting risks, with the benefits of continuing aspirin usually outweighing the risk of minor bleeding. Always confirm your medication instructions directly with your doctor, especially if you take other antiplatelet or anticoagulant drugs, to ensure the safest possible outcome. For more information on the guidelines, visit the American College of Cardiology website.

Frequently Asked Questions

If you forget your morning dose of aspirin, do not panic. Inform the medical staff as soon as you arrive for your procedure. They may administer the dose in the hospital or adjust the plan as necessary. It is crucial to be honest and upfront so they can ensure your safety.

For most patients, the typical low-dose aspirin (e.g., 81 mg) is continued. Some specific protocols may involve a higher or 'loading' dose, but you must follow your doctor's exact instructions. The most important factor is continuing the medication unless otherwise directed.

Yes, although it is rare for an angiogram. Your doctor might instruct you to stop aspirin if you have an extremely high bleeding risk due to another medical condition, a severe bleeding disorder, or an active ulcer. This decision is made on a case-by-case basis.

Your doctor will provide a list. Common medications to stop temporarily include other, more potent blood thinners like warfarin (Coumadin) or novel oral anticoagulants (NOACs), as well as certain diabetes medications like metformin. Other daily medications, like blood pressure pills, are usually continued.

You should receive clear pre-procedure instructions from your care team well in advance of your angiogram. If you have not, contact your cardiologist's office immediately to clarify your medication schedule and any fasting requirements.

If you've had a stent placed, continuing antiplatelet therapy (often including aspirin) is critically important to prevent stent thrombosis. In this case, you should absolutely continue your aspirin unless told otherwise. For dual antiplatelet therapy, a cardiology consultation is often recommended.

If your doctor instructs you to stop any medication, they will also tell you when to resume it. For potent blood thinners, this may be a day or two after the procedure, once adequate hemostasis has been achieved at the catheter insertion site. Always follow the specific restart instructions provided by your medical team.