Macrothrombocytes in the peripheral circulation of patients with cardiogenic hypertrophic osteoarthropathy.

The objectives of this study were: first, to determine the platelet morphology in the peripheral circulation of patients with cyanotic congenital heart diseases and thus its possible link to the development of hypertrophic osteoarthropathy. Second: to test the mathematical model which proposes that in normal individuals megakaryocytes are fragmented in the lungs. We prospectively studied 14 patients with cyanotic heart disease and clubbing of the 20 digits, and compared them with 14 randomly assigned controls. We measured the platelet count, mean platelet volume (MPV) and platelet volume distribution curve (PVDC). Patients had a significantly lower platelet count (x +/- SD, 171,528 +/- 81,810 vs 319,929 +/- 69,460, p less than 0.001) and larger MPV (11.028 +/- 3.09 vs 8.414 +/- 0.79, p less than 0.005). The PVDC of the controls were uniform, in all cases showing a log-normal configuration. The patient's curves were different; they lost the log-normal shape and demonstrated a heterogeneous platelet population. These findings agree with the mathematical model which proposes that in normal individuals platelets are generated in the lungs, and also suggest a role for the macrothrombocytes in the pathogenesis of cardiogenic hypertrophic osteoarthropathy.