Coronary slow flow in patients with impaired glucose tolerance and insulin resistance

Abstract
Background
The relationship between coronary slow flow (CSF) and insulin resistance (IR) is still a subject of debate with conflicting data. So the aim was to assess the relationship between IR as measured by IR index (HOMA-IR) and coronary slow flow as measured by the TIMI frame count in patients which (impaired glucose tolerance (IGT) and IR.

Results
Out of 87 patients enrolled, 64 (73.6%) patients were assigned to the IGT group while 23 (26.4%) patients were assigned to the NGT group. There were significantly higher BMI (30.15 ± 2.29 vs 23.90 ± 2.5, P < 0.001), waist circumference (105.05 ± 9.0.06 vs 92.92 ± 16.5, P < 0.001), and frequency of hypertension (60.9% vs 34.8, P = 0.03). Also, there were significantly higher 2-h post-prandial (hPP) glucose (161 ± 30 vs 110 ± 20, P < 0.05), fasting serum insulin level (9.56 ± 2.5 vs 7.03 ± 2.1, P < 0.001), HDL (40 ± 6.5 vs 49 ± 5.6, P < 0.001), HOMA-IR index (2.84 ± 0.03 vs 1.6 ± 0.05, P < 0.05), and mean TIMI frame count (33 ± 5 vs 26 ± 4, P < 0.001) among the IGT group, while HDL was significantly lower in the IGT group (40 ± 6.5 vs 49 ± 5.6, P < 0.001). There was a highly significant positive correlation between TIMI frame count and HOMA-IR (r = 0.43, P < 0.001); predictors that add significance to the model were age > 50 years, hypertension, high waist circumference, HDL < 35, and HOMA-IR. For HOMA-IR (OR 95% CI = 1.9 (1.05–3.49), P = 0.02 demonstrating that HOMA-IR is a powerful independent predictor of high TIMI frame count (Table 4).

Conclusion
IR is an independent risk factor for slow coronary flow in patients with IGT. Those with evident coronary slow flow, IGT should be managed aggressively even before any evidence of frank diabetes. Also, IR workup should be recommended among the other standard workup for those patients; if documented, targeting IR in such patients should be a priority (whenever possible) while selecting medications for comorbid cardiac disease, as well as using interventions targeted against IR should be considered among the other standard management for slow flow.