INOCA – Ischaemia with Non Obstructive Coronary Artery

INOCA – Ischaemia with Non Obstructive Coronary Artery

What happens if the angiogram is normal but patient still have chest pain? Can you have heart pain with normal coronary arteries?

There is also a small group of patients who come to me with classical symptoms of heart pain (angina) and often with abnormal exercise ECG. Yet they may have normal CT coronary angiogram showing widely patent heart vessels. This group of patients may have Coronary Microvascular Disease (CMD). Although the coronary microvascular system is one of the main components of coronary circulation, its relevance has been underestimated for a long time, since micro-vessels are invisible by the current imaging techniques, and their function may be assessed only indirectly. More specifically, 50-65% of patients with angina with non-obstructive coronary artery disease are believed to have Coronary Microvascular Dysfunction (CMD). Many of these patients were discharged from follow up as the conventional imaging tests were normal. They are then left frustrated without a firm diagnosis of their symptoms and often end up visiting many doctors across various specialties looking for a diagnosis and treatment. Worse still many ended up being admitted to hospital repeatedly with heart attack.
There is now a new test using the latest technology to assess the microvascular disease. It is carried out the same time as the invasive coronary angiogram with a special pressure wire inserted into the coronary artery. The microvascular physiology is then measured with thermodilution technique. The measured intramuscular resistance (IMR) will provide an objective assessment for CMD. In experienced hands, it usually takes an extra 10 to 15 min to perform the test during the coronary angiogram.
Patient with normal coronary angiogram and also have CMD ruled out can be reassured and not require further cardiovascular investigations and therapies. Whereas those with CMD benefit not just from having a confirmed diagnosis but allow the cardiologist tailor the treatment and improve their quality of life.
  1. Marinescu MA, Löffler AI, Ouellette M, et al. Coronary microvascular dysfunction and microvascular angina: a systematic review of therapies. JACC Cardiovasc Imaging. 2015;8:210-220. doi:10.1016/j.jcmg.2014.12.008.
  2. 2019 ESC Guidelines for the diagnosis and management of chronic coronary syndromes. Eur Heart J. 2020 Jan 14;41(3):407-477
  3. An EAPCI Expert Consensus Document on Ischaemia with Non-Obstructive Coronary Arteries in Collaboration with European Society of Cardiology Working Group on Coronary Pathophysiology & Microcirculation Endorsed by Coronary Vasomotor Disorders International Study Group. European Heart Journal, Volume 41, Issue 37, 1 October 2020

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Our Doctor

Dr. Paul Ong

Senior Consultant Cardiologist

BA (Cambridge)
MB BChir (Cambridge)
MA (Cambridge)
MRCP (UK)
CCST Cardiology (UK)
FRCP (London)
FESC (Europe)