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A hemorheological perspective on coronary microvascular dysfunction: Association of erythrocyte parameters with
Abdulrahman AlQazzaz1, Yanfeng Lu1, Jasmine Yimeng Bao2
1Department of Cardiology, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China.
Insights
Higher red blood cell (RBC) counts, hematocrit, and hemoglobin are linked to increased coronary microvascular resistance. These RBC markers may indicate microvascular dysfunction, especially in non-left anterior descending vessels.
Area of Science:
- Cardiology
- Hematology
- Vascular Biology
Background:
- Coronary microvascular dysfunction (CMD) is a key factor in myocardial ischemia, affecting patients with and without obstructive coronary artery disease.
- While the causes of CMD are diverse, hematologic parameters, particularly red blood cell (RBC) markers, have been implicated in cardiovascular outcomes.
- The specific relationship between RBC parameters and microvascular resistance, however, remains incompletely understood.
Purpose of the Study:
- To investigate the association between red blood cell (RBC) parameters and the angiography-derived index of microcirculatory resistance (angio-IMR).
- To determine if RBC markers can serve as indicators of microvascular dysfunction.
Main Methods:
- A retrospective analysis of 604 patients with intermediate coronary artery disease (30%-70% stenosis) was conducted.
- Red blood cell parameters were collected prior to angiography, and coronary microcirculatory resistance was quantified using the AngioPlus mQFR system.
- Multivariable linear regression models, subgroup analyses (including diabetes status), and sensitivity analyses were employed to assess the associations.
Main Results:
- Elevated RBC count, hematocrit (Hct), and hemoglobin (Hgb) were independently associated with higher angio-IMR.
- These associations remained significant after excluding hematocrit outliers and were consistent across diabetic and non-diabetic subgroups.
- The association between Hct and angio-IMR was significant in non-left anterior descending (LAD) vessels but not in LAD lesions.
Conclusions:
- Increased red blood cell parameters are independently correlated with elevated microcirculatory resistance, particularly in non-LAD coronary arteries.
- These findings suggest that RBC parameters could be valuable clinical markers for identifying microvascular dysfunction.
- Further research is warranted to explore the prognostic and therapeutic implications of these RBC markers in cardiovascular disease.
Background:
Coronary microvascular dysfunction (CMD) contributes to myocardial ischemia in patients both without obstructive coronary artery disease (e.g., MINOCA/INOCA) and in those with co-existing epicardial stenosis. While its etiology includes structural and functional causes. hematologic parameters have been linked to cardiovascular outcomes. However, the relationship between red blood cell (RBC) markers and microvascular resistance remains poorly characterized. We aim to evaluate whether RBC parameters are correlated with the angiography-derived index of microcirculatory resistance (angio-IMR).
Methods:
This retrospective study evaluated the association between red blood cell (RBC) parameters and angio-IMR in patients with intermediate coronary artery disease (30%-70% stenosis). Data were analyzed from 604 patients, comprising 733 lesions; red blood cell parameters were obtained during hospitalization prior to angiography. Coronary microcirculatory resistance was derived using the AngioPlus mQFR system. Multivariable linear regression models adjusted for confounders. Subgroup analyses assessed effect modification by diabetes status, and sensitivity analyses excluded hematocrit outliers, and analyses stratified by vessel (left anterior descending (LAD), left circumflex (LCx), right coronary artery (RCA)).
Results:
Higher RBC, Hct and Hgb were independently associated with elevated angio-IMR after full adjustment (RBC: β = 0.182, P < 0.001; Hct: β = 0.019, P < 0.001; Hgb: β = 0.006, P < 0.001). Results remained robust after excluding Hct outliers (β = 0.020, P < 0.001) and consistent across diabetic (P = 0.007) and non-diabetic subgroups (P = 0.012). The association was significant in non-LAD vessels (Hct: β = 0.022, P < 0.001) but not in LAD lesions (Hct: β = 0.008, P = 0.357).
Conclusion:
Elevated RBC parameters are independently associated with increased microcirculatory resistance, particularly in non-LAD vessels. These findings suggest that RBC parameters may serve as clinically relevant markers of microvascular dysfunction, warranting further investigation into their prognostic and therapeutic implications.
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