Background: Thrombus formation at the dilation site has been suggested to initiate the restenosis process after percutaneous transluminal coronary angioplasty (PTCA). High haemoglobin concentrations may predispose to thrombus formation by increasing blood viscosity, slowing coronary blood flow and increasing thrombocyte adhesion.
Methods: Pre-PTCA blood haemoglobin concentrations (Hb) in 44 patients with symptomatic restenosis > or = 50% of the vessel diameter (Group A) were compared with Hb in the remaining 215 patients in a consecutive study population (Group B).
Results: Median Hb (range) was 149 (119-164) g/l in Group A and 142 (117-164) g/l in Group B, P = 0.004. Odds ratio (95% CI) for symptomatic restenosis was 3.22 (1.62-6.42) when Hb was dichotomised according to the median in the entire material. Hb, but not sex was a significant risk factor in multivariate analysis.
Conclusion: Hb is a hitherto not recognized factor associated with the risk of symptomatic restenosis after PTCA and may be a link coupling male sex with increased risk of restenosis.