Cardiac Rehabilitation in Non-Obstructive Ischemic Heart Disease (INOCA).

INOCA – Considerations and New Evidence in Cardiovascular Rehabilitation

Cardiovascular rehabilitation and prevention for Ischaemic Non-Obstructive Coronary Artery Disease (INOCA)

Today, we will discuss INOCA, the uncertainty surrounding its optimal management, and the apparent lack of training, knowledge, and confidence among healthcare professionals in managing this condition. Recent studies have shown that many healthcare professionals either lacked the necessary knowledge and skills to support individuals with INOCA or did not believe that rehabilitation programmes were appropriate for this population.

Commonly recommended interventions included:

• Two non-supervised exercise sessions per week for eight weeks, performed at home

• General physical activity and exercise advice

• Behavioural health support

• Psychological support

• Smoking cessation

• Weight management and dietary support

• Medication review and counselling

  
  

On the other hand, individuals living with INOCA often report frustration with the way healthcare professionals manage their condition. Clinical attention is frequently focused on specific diagnostic tests, while patients’ symptoms are sometimes underestimated, despite repeated emergency department visits with infarction-like symptoms. Recently, however, there has been increasing awareness within the scientific community and healthcare systems regarding INOCA. It has also been suggested that, in some cases, post-traumatic stress disorder (PTSD), panic attacks, and other psychological factors may influence cardiac function and contribute to symptom presentation.

Understanding INOCA

To better understand INOCA, it is important to differentiate it from obstructive ischaemic coronary artery disease. Obstructive coronary artery disease is characterised by atherosclerotic plaques causing significant stenosis (>50–70%) in the major coronary arteries.

In contrast, Ischaemic Non-Obstructive Coronary Artery Disease (INOCA) represents a broader umbrella of conditions where myocardial ischaemia occurs in the absence of significant coronary artery obstruction. This is often due to endothelial dysfunction, coronary microvascular dysfunction, myocardial or vascular spasms, and abnormal vascular regulation (Rahman et al., 2019).

More specifically, ischaemia in INOCA is typically caused by microcirculatory dysfunction or vasospasm, including:

1. Coronary Microvascular Dysfunction (MVD)Dysfunction of small intramyocardial vessels that fail to dilate appropriately. This condition is more prevalent in women, individuals with diabetes, and those with hypertension.

   
   

2. Vasospastic (Prinzmetal) AnginaTransient spasms of large or small coronary arteries, which may result in complete ischaemia despite the absence of atherosclerotic stenosis. (Red flag condition).

   
   

It is estimated that up to 46% of individuals undergoing coronary angiography may have INOCA rather than obstructive coronary artery disease (Ford et al., 2018). Additionally, approximately 40% of patients presenting with chest pain are diagnosed with INOCA. Individuals with INOCA are at increased risk of developing heart failure with preserved ejection fraction and myocardial infarction (Taqueti et al., 2018; Maddox et al., 2014).

Cardiovascular Rehabilitation and Management of INOCA

Participation in cardiovascular rehabilitation programmes is well established as an effective intervention for individuals with coronary artery disease. Evidence suggests that cardiac rehabilitation reduces cardiovascular mortality for more than three years and hospital admissions for over two years, while significantly improving quality of life and overall health outcomes (Dibben et al., 2021; Powell et al., 2018). Both centre-based and home-based cardiac rehabilitation programmes have been shown to be effective in reducing myocardial infarction risk and improving quality of life. For individuals with INOCA, symptoms often worsen during cold weather, which may create additional barriers to participation in rehabilitation programmes during winter months. Patients frequently report symptom exacerbation triggered by cold exposure, meals, physical exhaustion, and emotional stress.

Implications for Rehabilitation Practice

Given these considerations, careful patient assessment and programme design are essential. There is a clear need for improved education and specialised training related to INOCA, as well as greater flexibility in rehabilitation delivery, including both home-based and centre-based programmes. Rehabilitation programmes for individuals with INOCA should be highly individualised and fully integrated into cardiac rehabilitation services. Exercise prescription should be informed by cardiology assessments, including identification of heart rate thresholds at which symptoms occur.

Exercise intensity should be carefully defined, and the use of a “grey zone” or buffer heart rate zone is recommended to minimise symptom onset both during and after exercise.

References:

-Nichols, S., S. Dawkes, A. Cowie, S. Brown, C. Berry, and H. Humphreys. 2025. “ Cardiovascular Prevention and Rehabilitation for Ischaemic Non-Obstructive Coronary Artery Disease: Implementation Considerations From a Survey of UK Health Professionals.” Journal of Advanced Nursing 1–10. https://doi.org/10.1111/jan.70023.

Humphreys H, Paddock D, Brown S, et al. Exploring patients’ views regarding the support and rehabilitation needs of people living with myocardial ischaemia and no obstructive coronary arteries: a qualitative interview study. BMJ Open 2024;14:e086770. doi:10.1136/ bmjopen-2024-086770

Humphreys H, Paddock D, Brown S, et al. Living with myocardial ischaemia and no obstructive coronary arteries: a qualitative study. Open Heart 2024;11:e002569. doi:10.1136/ openhrt-2023-002569

Powell, R., G. McGregor, S. Ennis, P. K. Kimani, and M. Underwood.2018. “Is Exercise-Based Cardiac Rehabilitation Effective? A SystematicReview and Meta-Analysis to Re-Examine the Evidence.” BMJ Open 8:e019656.

Rahman, H., D. Corcoran, M. Aetesam-ur-Rahman, S. P. Hoole, C.Berry, and D. Perera. 2019. “Diagnosis of Patients With Angina andNon- Obstructive Coronary Disease in the Catheter Laboratory.” Heart105: 1536–1542.

Taqueti, V. R., S. D. Solomon, A. M. Shah, et al. 2018. “CoronaryMicrovascular Dysfunction and Future Risk of Heart Failure WithPreserved Ejection Fraction.” European Heart Journal 39: 840–849

Ford, T. J., S. Bethany, G. Richard, et al. 2018. “Stratified MedicalTherapy Using Invasive Coronary Function Testing in Angina.” Journalof the American College of Cardiology 72: 2841–2855.

Maddox, T. M., M. A. Stanislawski, G. K. Grunwald, et al. 2014.“Nonobstructive Coronary Artery Disease and Risk of MyocardialInfarction.” JAMA 312: 1754–1763.

Dibben, G., J. Faulkner, N. Oldridge, et al. 2021. “Exercise-BasedCardiac Rehabilitation for Coronary Heart Disease.” Cochrane Databaseof Systematic Reviews 11: CD001800. https://doi.org/10.1002/14651858.CD001800.pub4.