CardioNerds (Drs. Apoorva Gangavelli, Rebecca Garber, and Tina Reddy discuss INOCA with Dr. Claire Raphael. Audio editing by CardioNerds Academy intern, student doctor Pacey Wetstein.

This episode was produced as part of the CardioNerds Academy curriculum by House Einthoven under the guidance of House Chief, Dr. Apoorva Gangavelli, and Academy Program Director, Dr. Gurleen Kaur. A matching review article will be published in US Cardiology Review, the official journal of CardioNerds.

Non-obstructive coronary artery disease (CAD) is more common than often recognized, particularly in women and individuals with risk factors like diabetes or hypertension. Conditions such as INOCA, ANOCA, and MINOCA can cause ischemia and chest pain despite “clean” angiograms, often due to microvascular dysfunction, coronary spasms, or subtle plaque. Diagnosing these conditions requires advanced imaging or invasive studies to assess blood flow and vessel function. Treatment focuses on reducing cardiovascular risk with aspirin, statins, ACE inhibitors, or ARBs, and managing symptoms with beta-blockers or calcium channel blockers. The key takeaway: A normal angiogram doesn’t rule out disease, and these patients need a comprehensive, evidence-based approach to care.

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Pearls:

When patients present with chest pain but do not have obstructive coronary artery disease, the story does not end there! Other pathologies that must be ruled out include spontaneous coronary artery disease (SCAD), coronary vasospasm, microvascular disease, Takotsubo, and cardiomyopathy. A TTE can help rule out other pathologies. Cardiac MRI can help identify myocardial fibrosis, scarring, or edema that may suggest prior events or alternative diagnoses.
About 60-70% of INOCA cases are in women. However, it is estimated that about half of the patients with so-called “normal” angiograms actually have positive stress tests. Patients with elevated troponins are more likely to have recurrent events. Patients with INOCA are more likely to come back to the ER multiple times before getting diagnosed. These patients have a 1.4x increased risk of adverse cardiovascular events (such as HFpEF, MI, and recurrent hospitalizations for cardiac chest pain).
INOCA is a complex condition with a variety of causes, primarily linked to microvascular disease. Within microvascular disease, there are different “endotypes” (types or subcategories) classified by specific characteristics. In centers that conduct microvascular testing, patients are categorized as endothelium-independent or endothelium-dependent, based on their responses to adenosine or acetylcholine during testing. Additionally, microvascular disease can be classified as either structural or functional, depending on the results of tests measuring microvascular resistance.
The field is moving towards the term ANOCA, or angina with non-obstructive coronary arteries, to include patients with anginal symptoms without objective ischemia.
The field is moving toward using genotyping and hemodynamic testing to guide first-line therapies for microvascular disease, a heterogeneous condition. Current treatments mostly come from obstructive coronary artery disease, but specialized approaches—like the coronary sinus reducer—may offer unique benefits for microvascular disease.
Treatment includes sublingual nitroglycerin, ACE inhibitors/ARBs, and beta-blockers. Remember to also treat any additional comorbidities, such as diabetes, hypertension, and hyperlipidemia. Unfortunately, many of these patients may still have refractory chest pain, so it is important to reassure them. These patients can still exercise, but they may be hesitant to do so for fear of having chest pain. Cardiac rehab may be helpful for these patients as it helps them build up their tolerance.

Pearls:

References