0488 The Relationship between Myocardial Blood Flow and Diastolic Function in a Clinical Population with Obstructive Sleep Apnea

Abstract

Abstract Introduction Emerging evidence links abnormal myocardial blood flow reserve (MBFR), a marker of coronary microvascular dysfunction (CMD), and heart failure with preserved ejection fraction (HFpEF). However, the relationship between CMD and diastolic dysfunction (DD) in patients with OSA remains unclear. We analyzed the relationship between OSA, abnormal MBFR and markers of DD in a patient cohort. Methods Using healthcare records, we generated a cross-sectional database of 231 individuals who had sleep testing, echocardiogram(s), and cardiac PET stress test. Abnormal MBFR was defined as the stress-to-rest ratio of myocardial blood flow < 2.0. We created DD score with a point each given to a) left atrial volume index (LAVI) ≥34, b)average E/e’ ratio>14/lateral e’>10/medial e’>7, and in a subgroup of 122 individuals with available data we added c)tricuspid regurgitation jet (TR) velocity > 2.7m/s. Higher scores suggest greater likelihood of DD. Models were adjusted for demographics and cardiometabolic risk factors. Results The mean (SD) age and BMI was 60(11) years and 39.5(8.7) kg/m2; 61% were female. Eighty-four participants had severe OSA (apnea-hypopnea index ≥ 30/hr). Compared to non-severe OSA, severe OSA was associated with 2-fold odds of abnormal MBFR (adjusted OR [aOR) 2.1, 95%CI:1.1–4.0). However, there was no association with abnormal LAVI, abnormal E/e’ (average E/e’>14 vs. < 9), or elevated TR velocity. In the adjusted model, abnormal MBFR was associated with abnormal E/e’ (aOR 4.4 [95% CI: 1.6-11.8]) and elevated TR velocity (aOR: 3.7 [95%CI: 1.3-10.9]). Abnormal MBFR was associated with increase in DD score (range 0–2; aOR per-unit increase = 1.7 [95% CI: 1.0-3.0]. In the subset with data on TR velocity, abnormal MBFR was associated with a three-fold increase in the odds of a unit increase in DD score (range 0–3; aOR 3.3 [95% CI: 1.5,7.4]). The association between abnormal MBFR and DD was present regardless of OSA severity. Severe OSA was not associated with DD. Conclusion Abnormal MBFR/CMD may be implicated in the development of DD and HFpEF in patients with OSA. MBFR assessment may be useful in HFpEF risk stratification in non-severe OSA. Larger studies are required to determine the role of CMD in the development of DD/HFpEF in OSA. Support (if any)