Metabolic syndrome (MS) refers to a group of cardiovascular risk factors associated with endothelial dysfunction and impaired coronary blood flow (CBF). Homocysteine (Hcy) is another risk factor for the development of insulin resistance and endothelial dysfunction. However, the relationship between Hcy levels and CBF in patients with MS has not been investigated specifically. In the present study, we aimed to evaluate the relationship between Hcy levels and CBF in MS patients with normal coronary arteries.
The study population included 36 patients with MS (20 males, 16 females; mean age = 55 ± 9 years) and 36 control subjects (20 males, 16 females; mean age = 51 ± 7 years). All subjects had angiographically proven normal coronary arteries. Plasma Hcy concentrations were evaluated after a fast of 12 h or longer. The CBF rates of all subjects were documented by the thrombolysis in myocardial infarction (TIMI) frame count method.
The TIMI frame counts for each major epicardial coronary artery and mean TIMI frame count were found to be significantly higher in the MS group compared with the control group (left anterior descending coronary artery (LAD): 53 ± 26 vs. 39 ± 17; p = 0.01, left circumflex artery (LCx): 32 ± 12 vs. 26 ± 11; p = 0.01, right coronary artery (RCA): 33 ± 14 vs. 26 ± 12; p = 0.02, mean TIMI frame count: 39 ± 16 vs. 20 ± 12; p = 0.01). Plasma Hcy levels in patients with MS were significantly higher compared with controls (MS group = 11.6 ± 4 and control group = 9.6 ± 2.6; p = 0.01). Additionally, plasma Hcy levels were positively correlated with each calculated TIMI frame count value in the MS group (LAD, r: 0.28 and p = 0.006; LCx, r: 0.25 and p = 0.022; RCA, r: 0.26 and p = 0.042; mean TIMI frame count, r: 0.28 and p = 0.004).
Plasma Hcy levels and TIMI frame counts were significantly higher in patients with MS. Impaired CBF in MS may be related to elevated levels of Hcy, even if Hcy levels are normal.