[Relation between plasma fibrinogen and the function of collateral coronary vessels]

The role of fibrinogen in LV function, especially after myocardial infarction, is still debated. We therefore investigated the relation between plasma fibrinogen, LV function and ischemic tolerance in 87 patients (average age 58.5 years) with proximal occlusion of the left anterior descending artery (LAD) and retrograde filling through noncompromised collaterals. Compared to a control group (n = 65; average age 57.0 years) study patients revealed significantly higher plasma fibrinogen levels (average 342.5 vs 316.1 mg/dl; p < 0.025) and a reduced ejection fraction (54.6 vs 75.5%; p < 0.0005). Study patients with collaterals were divided into three groups with increasing fibrinogen concentrations: Group I (n = 29) averaged 261 mg/dl (191-303), group II averaged 333.3 (304-362) and group III averaged 433.3 (364-742) (p < 0.0005). There were no significant differences regarding age, height, weight, number and age of previous infarctions and concomitant medical treatment; group III revealed a significantly higher proportion of women (21%) compared to group I (0%) (p < 0.005); group III also revealed significantly lower HDL-cholesterol and higher triglyceride levels compared to group I and group II, respectively (p < 0.05). Hematocrit, hemoglobin concentration, total and LDL-cholesterol showed no group differences. Group I with a low fibrinogen had the lowest endsystolic volume index (LVESVI) and highest ejection fraction (EF) (34.6 ml/m2 and 61.0%, respectively), whereas in patients of group II LVESVI amounted to 36.5 ml/m2 and EF to 57.3%, and in group III with the highest plasma fibrinogen levels LVESVI was 48.4 ml/m2 (group I, II vs III: p < 0.05) and EF 45.7% (group I, II vs III: p < 0.01). EF decreased exponentially with increasing fibrinogen concentrations (r = 0.5; p < 0.0005). Group III showed significantly higher LV enddiastolic pressures (19.1 mm Hg) compared to group I and II (14.6 and 14.4 mm Hg, respectively; p < 0.05). Fifteen patients in group I, 21 in group II, and 24 in group III showed akinetic LV wall segments (group I vs III: p < 0.0125). In addition, 21 patients in group I, 17 in group II, and only 10 in group III revealed exercise-induced myocardial ischemia (group I, II vs III; p < 0.05). In patients with ischemic ST-depression systolic rate pressure product (SRPP) at the onset of ischemic symptoms was 266.8 mm Hg x min-1 x 10(2) in group I, 246.8 in group II and 195.0 in group III (group I, II vs III; p < 0.005).(ABSTRACT TRUNCATED AT 400 WORDS)