Significant Association of Serum Albumin With the Severity of Coronary Microvascular Dysfunction Using Dynamic CZT-SPECT

Objective: Both low serum albumin (SA) concentration and coronary microvascular dysfunction (CMD) are risk factors for the development of heart failure (HF). We hypothesized that SA concentration is associated with myocardial flow reserve (MFR) and implicated in pathophysiological mechanism of HF. Methods: We retrospectively studied 454 patients undergoing dynamic cardiac cadmium-zinc-telluride myocardial perfusion imaging from April 2018 to February 2020. The population was categorized into three groups according to SA level (g/dL): Group 1: >4, Group 2: 3.5-4, and Group 3: <3.5. Myocardial blood flow (MBF) and myocardial flow reserve (MFR, defined as stress/rest MBF ratio) were compared. Results: The mean age of the whole cohort was 66.2 years, and 65.2% were men. As SA decreased, stress MBF (mL min(-1) g(-1)) and MFR decreased (MBF: 3.29 +/- 1.03, MFR: 3.46 +/- 1.33 in Group 1, MBF: 2.95 +/- 1.13, MFR: 2.51 +/- 0.93 in Group 2, and MBF: 2.64 +/- 1.16, MFR: 1.90 +/- 0.50 in Group 3), whereas rest MBF (mL min(-1) g(-1)) increased (MBF: 1.05 +/- 0.42 in Group 1, 1.27 +/- 0.56 in Group 2, and 1.41 +/- 0.61 in Group 3). After adjusting for covariates, compared with Group 1, the odds ratios for impaired MFR (defined as MFR < 2.5) were 3.57 (95% CI: 2.32-5.48) for Group 2 and 34.9 (95% CI: 13.23-92.14) for Group 3. The results would be similar if only regional MFR were assessed. The risk prediction for CMD using SA was acceptable, with an AUC of 0.76. Conclusion: Low SA concentration was associated with the severity of CMD in both global and regional MFR as well as MBF.