Diagnosis of Coronary Ischemia – When to Consider an Angiography?

Can angiography be avoided? Alternative Diagnostic Methods

Angiography has become one of the most important medical discoveries due to its ability to diagnose and investigate numerous problems affecting blood vessels, including coronary artery disease. Since this is the only method currently used to determine if a stent is needed or if a pre-placed stent is in restenosis, alternative diagnostic methods are being looked into to reduce risks and costs. 

What is Angiography?

Angiography is a diagnostic procedure that uses imaging to show how blood flows through blood vessels or the heart. During an angiography, a special dye, a contract agent, is injected into the area being examined which highlights the blood vessels as it moves through the vessels. The X-ray images created during angiography, angiograms, are then used to view the vessels. 

This procedure is done in a hospital and usually takes between 30 minutes and 2 hours. An incision is made over an artery, usually near a patient’s groin or wrist, and a tube called catheter is inserted into the artery. Once the catheter is inserted into the artery, the contrast agent is injected into the catheter to highlight the vessels.

When is an Angiogram Needed?

An angiography is a diagnostic procedure that is used to examine vessels and the blood flow through them. It is used to diagnose vascular conditions including coronary arterial disease. Some reasons why a patient may need an angiogram are³:

  • To check the health of the target vessels and observe how the blood flows through them
  • Diagnose or investigate vascular conditions such as aneurysms or ischemic events
  • Assess the function of a stent and identify potential issues such as restenosis 

Oftentimes a patient may have symptoms of stent failure, to learn more, check the following article here. Therefore, the physician may consider performing an angiogram to confirm the diagnosis.

Are angiograms dangerous?

Angiograms are generally considered safe, however just like any medical procedure, there are always risks involved. Here are somethings to consider:

  • Pain and discomfort from introducing the catheter in the artery
  • Risk of bleeding or bruising at the location where the catheter is inserted
  • Risk of infection at the location where the catheter is inserted
  • Risk of an allergic reaction to the contrast dye used during the procedure
  • Risk of damage to the blood vessel or surrounding tissue during the procedure
  • Risk of radiation exposure during the procedure

Are There Alternative Diagnostic Methods for Angiography?

Angiographies have become the gold standard in diagnosing coronary vascular events and they are the definitive procedure to determine the status of a stent. This procedure uses radiation to produce an image to show how blood flows through the heart and the adjacent vessels such as the coronaries, and is able to highlight the main conditions affecting them. However, it is an invasive, ionizing and costly procedure. Since this is a procedure performed in the angio suite, it requires doctors, nurses, anesthesiologists, medications, and technological equipment. Therefore, not only is it a very expensive procedure but also puts a strain on the patient because of its invasiveness. To determine whether a stent needs to be placed or to check its functionality, an angiography is necessary. However, not all angiographies reveal coronary ischemia or stent failure.

The most recent studies reveal that 77% of patients underwent a follow-up angiography between 3 and 8 months after a stent placement procedure¹ but only 35.7% of all stents experienced restenosis². This means that only a small fraction of angiograms were actually required, therefore, more cost-effective and less invasive alternative methods are being looked at to avoid unnecessary angiography procedures. These alternatives should be able to determine whether a stent has failed or the patient is experiencing restenosis. This would reduce risks for the patient as well as costs and radiation time.

Angiogram, Risk of Death

The risk of death resulting from angiograms is very low, and it is generally reported to be less than 1%.4 It’s important to note that the elderly population or those who suffer other health conditions, the risk of heart attack or stroke is higher. Overall while there is a risk associated with angiograms, it is very low. The benefits of the procedure often outweigh the risks, especially for those with heart disease.

Angiogram Risks in the Elderly

Age can increase the risk of an angiogram of the elderly population in several ways5 :
  • Are more likely to have other health conditions that can increase the risk of complications during and after the procedure. 
  • Arteries become stiffer, making it more difficult to place the catheter through the vessels 
  • Have an increased risk of infection 
  • Have kidneys that may not process the contrast as efficiently as a young patient

Are There Any Alternative Diagnostic Methods to Angiography?

Currently, there are a few non-invasive imaging techniques that can be used as an alternative to angiograms. However, these non-invasive techniques may not be suitable for all patients, and the decision to use them should be made on an individual basis.

Non-invasive Alternatives to Angiography

There is one non-invasive test that can be an alternative to an angiography, however this method does create a lot of false positives and is ionizing. A Coronary Computed Tomography angiography (CCTA) is an imaging test that produces images of  blood vessels in a patient’s heart. During the test, a dye is injected through a vessel, either in the wrist or leg, and can produce images of the heart muscle to be able to diagnose a variety of heart diseases.6

As this may be a non-invasive alternative to an angiography, the CCTA tests are far more expensive and often produce false positives. These tests are good for soft tissues however if there is any sort of metallic within the body, it would create an unclear picture. For example, if a patient would have a coronary stent, there is no clear way to determine the functionality of the stent since the metallicity would cause unclear images. This non-invasive alternative also has a very long waiting list, so it is possible to wait years for this imaging. 

The Future of Cardiac Diagnostics

The future of cardiac diagnostics is promising. There is ongoing research and development aimed at improving the accuracy, speed, and accessibility of diagnostic tools.

Innovations in Diagnostic Techniques

Innovation advancements highlight ongoing research in the field of cardiac diagnostic technology. Some of the potential advancements in the cardiac diagnostic technology include:
  • Artificial Intelligence and Machine Learning: The use of AI and machine learning is expected to play a significant role in the future of cardiac diagnostics7 
  • Non-invasive imaging: (Such as NIMBLE Diagnostics) Provides detailed information about the structure and function of the heart without an invasive procedure8
  • Wearable technology: Improvement in smartwatches and fitness trackers is expected to play a role in early detection of heart disease7

The NIMBLE System

NIMBLE Diagnostics has created the NIMBLE System that will be able to diagnose coronary stents in a non-invasive, non-ionizing setting. This device uses microwave imaging to view the coronary stents to determine its functionality. This device would put the patient at less risk and promises to be much more cost-effective than the angiography.  

The NIMBLE System is a first in class microwave based medical device that allows the continuous, non-invasive monitoring of patients with implanted stents. The NIMBLE System could become the first point of care to accurately measure and quantify stent malfunction. Some hospitals still perform routine 6 months follow up to ensure the correct stents’ status to reduce the risk of a second heart attack. If you wish to learn how to frequently Monitor a stent after its placement click on the link here.



The angiography saves lives and it is a low-risk procedure. However, there are downsides such as its invasiveness, elevated costs as well as the scientific evidence revealing that up to 65% of these procedures are unnecessary. This is why alternatives are being looked into to increase the positive impact of coronary diagnosis. With the implementation of non-invasive technology, such as the NIMBLE system, patient care will improve as well as reducing costs to the healthcare system. 

The information published in this Blog article, or in NIMBLE DIAGNOSTICS website, is provided for information purposes only and does not and cannot be considered as a consultation, treatment, therapy, or medical or clinical prescription, nor is it a substitute for treatment, diagnosis, therapy, or supervision by a healthcare professional. The information published is neither intended to be used as a guide and should not serve nor be used as an exclusive orientation for the healthcare professionals to make decisions about the treatment and therapy of their patients, nor does it replace the healthcare professionals’ criteria. NIMBLE DIAGNOSTICS makes no warranties as to the accuracy, suitability, or completeness of the information provided, and shall not be held responsible for any decisions made based on the information provided on this Blog article, NIMBLE DIAGNOSTICS website or any other websites linked or referenced in NIMBLE DIAGNOSTICS website.


  1. Rodés-Cabau, Josep, et al. “Frequency and Clinical Significance of Myocardial Ischemia Detected Early after Coronary Stent Implantation.” Journal of Nuclear Medicine, Society of Nuclear Medicine, 1 Dec. 2001, jnm.snmjournals.org/content/42/12/1768.

  2. “2022 AHA/ACC/HFSA Guideline for the Management of Heart Failure: A …” Edited by Adnan Kastrati et al., JACC Journals, Nov. 2001, www.jacc.org/doi/10.1016/j.jacc.2021.12.012.

  3. “Angiography.” NHS Inform, 24 Oct. 2023, www.nhsinform.scot/tests-and-treatments/scans-and-x-rays/angiography/.

  4. “Coronary Artery Disease: Should I Have an Angiogram?” Government of Alberta Personal Health Portal, myhealth.alberta.ca/Health/pages/conditions.aspx?hwid=hw267214. Accessed 13 Nov. 2023.

  5. Kunadian , Vijay. “Improving Heart Attack Treatments for Older Patients.” BHF, British Heart Foundation, www.bhf.org.uk/informationsupport/heart-matters-magazine/research/heart-attack-treatments-for-older-patients. Accessed 13 Nov. 2023.

  6. “Coronary Computed Tomography Angiography (CCTA).” Johns Hopkins Medicine, 23 Aug. 2021, www.hopkinsmedicine.org/health/treatment-tests-and-therapies/coronary-computed-tomography-angiography-ccta.

  7. Saltman, Adam. “The Future of Cardiac Health.” DAIC, 04 May 2022, www.dicardiology.com/article/future-cardiac-health.

  8. Di Carli, Marcelo F., et al. “The Future of Cardiovascular Imaging .” Circulation – AHA/ASA Journals, 21 June 2021, www.ahajournals.org/doi/10.1161/CIRCULATIONAHA.116.023511. 

Image Citation

“Test / Diagnostic Procedure: Invasive Coronary Angiography.” OneWelbeck, onewelbeck.com/tests-diagnostics/invasive-coronary-angiography/. Accessed 13 Nov. 2023.


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