Inoca and Its Diagnosis by Microvascular Study, A Case Report

Background and Clinical Significance: Ischaemia with non-obstructive coronary arteries (INOCA) has attained more recognition in recent decades. These patients may present with typical cardiac sounding chest pain but have no evidence of obstructed coronary arteries on coronary angiography. This presents a challenge to clinicians in terms of diagnosis and management. Coronary microvascular dysfunction (CMD), or coronary spasm (whether epicardial or microvascular) may be the cause of their presentation, and they usually require further invasive investigations of their coronary microvascular circulation to determine the cause. Case Presentation: This case involves a male patient in his 60s presenting with recurrent nocturnal chest pain, clinical and ECG evidence of ischaemia, and diagnostic findings from invasive coronary angiography and a microvascular study. These findings confirmed an absence of obstructive coronary artery disease (CAD) but demonstrated significant microvascular dysfunction, consistent with a diagnosis of microvascular angina according to the COVADIS criteria, as well as epicardial coronary artery spasm leading to complete vessel closure. This case highlights the clinical and diagnostic complexities of microvascular angina and coronary artery spasm. It also emphasises the importance of advanced diagnostic testing in confirming this challenging diagnosis. This case was interesting due to the patient having a final diagnosis of microvascular angina and coronary artery spasm at the same time. This case also demonstrates how 300 mcg of intracoronary nitrate was given to dilate a vessel in coronary spasm with positive effect. This finding was supportive of the final diagnosis given the clinical context of this patient. Conclusions: This case report demonstrates the diagnostic steps, from symptom assessment through to angiography and microvascular testing and would add to the existing knowledge of INOCA and aid in the understanding and management of these patients especially in centres where acetylcholine testing to confirm inducible epicardial coronary spasm is not available, like it was not in our centre (Blackpool Victoria Hospital).