Association Between Nocturnal Hypoxemia Parameters and Coronary Microvascular Dysfunction: A Cross-Sectional Study.

Area of Science:

• Cardiology
• Sleep Medicine
• Respiratory Medicine

Background:

• Obstructive sleep apnea (OSA) is increasingly recognized for its systemic effects.
• Coronary microvascular dysfunction (CMD) is a significant cardiovascular condition.
• The precise mechanisms linking OSA and CMD remain incompletely understood.

Purpose of the Study:

• To investigate the association between OSA-related nocturnal hypoxemia parameters and CMD.
• To determine if specific hypoxemia metrics correlate with the presence and severity of CMD.

Main Methods:

• Observational, single-center study involving patients undergoing polysomnography and coronary angiography.
• Coronary microvascular dysfunction (CMD) assessed using the angio-based index of microcirculatory resistance (AccuIMR).
• Logistic regression analyses performed to evaluate relationships between nocturnal hypoxemia and CMD, adjusting for confounders.

Main Results:

• Out of 133 patients, 72 (54.14%) had CMD.
• Patients with CMD showed higher prevalence of OSA and more severe nocturnal hypoxia.
• Minimum oxygen saturation (minSpO2) ≤90% and percentage of time with oxygen saturation <90% (T90) ≥5% were independently associated with CMD (P=0.004 and P=0.041, respectively).
• No significant association found between apnea-hypopnea index (AHI) and CMD.

Conclusions:

• Nocturnal hypoxemia parameters are significantly associated with coronary microvascular dysfunction (CMD).
• Specific hypoxemia metrics, such as minSpO2 and T90, may serve as more sensitive indicators of the OSA-CMD relationship than the AHI alone.