Microvascular Angina : A Diagnosis Hidden in Plain Sight
Authors: Samuels Curtis D. 
Published: June 2021

Background: Patients who are initially suspected of having ischemic heart disease, but in whom normal coronaries are discovered at angiography, are frequently believed to have pain of a non-cardiac aetiology. Micro vascular angina is hardly ever diagnosed save in peri-menopausal women. Physicians traditionally tend to view coronary microvascular disease and obstructive coronary artery disease as two separate entities. Notwithstanding, recent studies have begun to focus on endothelial dysfunction as being a key component in all cardiovascular diseases, with or without obstructive coronary lesions.

Hypothesis: Patients suspected of having obstructive coronary disease associated with a significant risk factor burden, but in whom normal coronaries are found at angiography, in reality possess microvascular dysfunction.

Objectives:

•	To determine the prevalence of normal coronaries at elective angiography compared to subjects with significant obstructive lesions.

•	To examine the influence of risk factor burden in patients who present normal coronaries in comparison with those who demonstrate obstructive lesions at angiography.

•	To suggest endothelial dysfunction as the common nexus underlying the disparities in cardiovascular morbidity observed among population samples.

Methods: A group of 90 patients were randomly selected from clinical files of those who underwent elective coronary angiography between January, 2013 and May, 2017. The study cohort was comprised of 55 males and 35 females between the ages of 43 to 84 years. All subjects presented chest pain suspected of being coronary in origin. Coronary risk factors were recorded for each patient and the results were compared with findings at coronary angiography and then correlated with those encountered in medical literature.

Results: Normal coronary angiograms were more prevalent in the African-Caribbean population (54.16%), than within the Mestizo-Mayan population (37.5%) Conversely, the finding of an obstructive lesion was more common in the Mestizo-Mayan population (56.25%), than within the African-Caribbean group (31.25%). The African-Caribbean group generally possessed a greater risk factor burden than their Mestizo-Mayan counterparts.

Mayan counterparts. The percentage of women with normal coronaries (52.94%) showed a slight increase over that of men (47.05%). Males possessed a prevalence for obstructive disease of almost 4 times greater (79.48% vs. 20.5%) than females, yet females demonstrated a greater risk factor burden than males in most risk parameters. Hypertension was the most prevalent risk factor followed by dyslipidaemia and diabetes mellitus but these factors were more commonly encountered in patients with “normal” coronaries, than in those with obstructive lesions.

Conclusion: Our study reported a significant number (56.66%) of “normal” coronaries at angiography. The majority (54.16%) of this figure pertained to the African-Caribbean sub-group, which in other studies also appeared to have a lesser coronary disease morbidity and mortality than their white counterparts despite having a greater risk factor burden. This is particularly true in the female African-Caribbean population. Several research papers have made reference to racial, ethnic and gender disparities in the manifestation of cardiovascular diseases. Paradoxically in some cases risk factor burden may be higher in the non-obstructive group rather than in the obstructive population. Convincing research has led us to believe that the vascular endothelium in its state of dysfunction plays a key role in explaining these disparities. Wherever cardiovascular risk factors exert their damage, endothelial injury and dysfunction ensues. Therefore, having an established risk factor burden portends microvascular dysfunction independently of any angiographic result.