The role of adrenergic activity in slow coronary flow and its relationship to TIMI frame count.

The aim of this study was to investigate the role of adrenergic activity in patients with slow coronary flow (SCF) and its relationship to TIMI frame count on the pathogenesis of SCF. Plasma noradrenalin and adrenalin concentrations at rest were compared in 51 patients diagnosed with SCF through coronary angiography and TIMI frame count; and 44 healthy controls with normal coronary flow (NCF). Furthermore, the relationship between TIMI frame count and noradrenalin and adrenalin levels was investigated. Plasma noradrenalin (127.9 +/-9.2 and 79.3 +/- 7.3 ng/mL, p < 0.0001) and adrenalin levels (63.9 +/- 2.6 and 44.7 +/- 2.8 ng/mL, p < 0.0001) were higher in patients with SCF when compared to patients with NCF. Noradrenalin and adrenalin levels were effected with SCF-dominant vessels with respect to TIMI frame count (p = 0.012 and p < 0.0001). Patients with SCF in 1, 2, or 3 vessels had different noradrenalin and adrenalin levels (p <0.003 and p < 0.0001). Patients with TIMI frame count above the 75th percentile had significantly higher noradrenalin and adrenalin levels when compared with those between the 25th-50th percentiles and below (p < 0.001 and p = 0.011, respectively). Correlation analysis established that both adrenalin and noradrenalin levels were correlated with TIMI frame counts of left anterior descending (LAD) and circumflex (Cx) arteries. Exercise testing revealed ischemia in 6 patients. Their TIMI frame counts were above the 75th percentile, and they had higher noradrenalin and adrenalin levels when compared with those without ischemia (p = 0.029, p = 0.045). Higher noradrenalin and adrenalin levels and correlation between TIMI frame count and ischemia in patients with SCF suggest that increased adrenergic activity may be the manifestation of slow coronary flow.