Coronary Hemodynamics and Microvascular Function

The coronary circulation is regulated by an intricate balance of epicardial conduit vessels and downstream microvasculature. Haemodynamic forces such as pressure gradients, blood viscosity and endothelial shear stress determine flow distribution across myocardial territories. In healthy individuals, dynamic changes in vessel calibre and microvascular resistance maintain an adequate coronary flow reserve (CFR) to match fluctuations in metabolic demand. Impairment at either the level of large arteries or the intramural network can lead to myocardial ischaemia despite the absence of obstructive lesions. Microvascular dysfunction arises from structural remodelling, endothelial dysfunction and inflammatory pathways, manifesting in phenomena such as coronary slow flow, reduced CFR and abnormal perfusion on imaging. Clinically, these alterations are linked to angina, arrhythmias and adverse outcomes. Emerging diagnostic tools—from invasive pressure‐wire assessment to advanced echocardiographic strain analysis—offer deeper insight into the interplay between haemodynamics and microvascular performance, informing tailored therapeutic strategies.

Research from Nature Portfolio

Recent studies have harnessed high-throughput sequencing to map transcriptomic and microRNA networks underlying coronary slow flow. These investigations identified immune-related hub genes and their regulatory microRNAs, shedding light on inflammatory mechanisms that compromise microvascular integrity and suggesting potential biomarkers for risk stratification. Complementary work using two-dimensional speckle-tracking echocardiography has revealed that slowed coronary transit correlates with impaired left atrial reservoir and booster function. Quantitative strain parameters diminished in affected patients and aligned with metrics of flow disturbance, linking microvascular impairment to atrial mechanics and highlighting monocyte percentage as an independent risk factor.

Research from all publishers

A novel nomogram integrating biochemical markers and coronary artery diameters has been validated to predict individual risk of coronary slow flow with high discrimination and calibration. Key predictors include N-terminal pro-B-type natriuretic peptide, high-density lipoprotein cholesterol and vessel calibre, offering a bedside tool to anticipate microvascular compromise. In parallel, systemic inflammation has been shown to drive microvascular dysfunction: the pan-immune-inflammation value (PIV) outperforms traditional indices such as neutrophil–lymphocyte and platelet–lymphocyte ratios in diagnosing slow flow. Earlier work further demonstrated that the systemic immune-inflammation index correlates positively with angiographic frame counts and independently predicts slow coronary transit, underscoring the role of chronic inflammation in microvascular impairment.

Coronary Hemodynamics and Microvascular Function publication trend

The graph below shows the total number of articles in coronary hemodynamics and microvascular function across all publications each year (not limited to Nature Index journals).

Technical terms

Coronary flow reserve (CFR): Ratio of maximal achievable coronary blood flow to resting flow, reflecting combined epicardial and microvascular capacity to augment perfusion.

Microvascular resistance: Opposition to blood flow within arterioles and capillaries, regulated by vascular tone, vessel density and structural remodelling.

Thrombolysis in Myocardial Infarction (TIMI) frame count: Quantitative measure of coronary dye transit time used to assess flow velocity in angiography.

Endothelial shear stress: Frictional force exerted by blood flow on the vascular endothelium, a key determinant of vessel function and remodelling.

References

1. Establishment and verification of a nomogram that predicts the risk for coronary slow flow. Frontiers in Endocrinology (2024).
2. Differential gene expression and miRNA regulatory network in coronary slow flow. Scientific Reports (2024).
3. Could Pan-Immune-Inflammation Value be a Marker for the Diagnosis of Coronary Slow Flow Phenomenon?. Cardiovascular Toxicology (2024).
4. Relationship between increased systemic immune-inflammation index and coronary slow flow phenomenon. BMC Cardiovascular Disorders (2022).
5. The effect of coronary slow flow on left atrial structure and function. Scientific Reports (2021).