Thrombocytopenia in congenital heart disease patients

Thrombocytopenia has been identified as a mechanism of the increased incidence of thromboembolism and death in hypoxemic congenital heart disease (CHD) patients. About 387 CHD patients (344 non-hypoxemic and 43 hypoxemic) were followed-up during a median of 34.3 (24.5; 49.9) months. Demographic, clinical, analytical parameters, and survival curves between CHD with platelet levels above and below 150,000/μl were determined. On one hand, in the subgroup of non-hypoxemic CHD patients, 8 out of 344 (2.3%) patients showed some type of bleeding and 8 (2.3%) patients showed some type of thrombosis. On the other hand, in the hypoxemic subgroup, 6 out of 43 (13.9%) patients had some type of bleeding and 5 (11.6%) patients showed some type of thrombosis. The binary logistic regression multivariate analysis being under oral anticoagulation/antiplatelet therapy (OR, 4.192 (1.207-14.550), p = 0.024) and having hypoxemia (OR, 4.041 (1.087-15.029); p = 0.037) favored the occurrence of bleeding. Meanwhile, the only factor which favored thrombosis was being hypoxemic (OR, 5.703 (1.334-24.387); p = 0.019). Also, being hypoxemic (OR, 0.217 (0.070-0.670), p = 0.008) and having a high MPV (OR, 0.534 (0.383-0.744); p = 0.001) favored a low platelet count (< 150 × 10(3)/µl). Kaplan-Meier survival analysis showed significant differences between CHD patients with a platelet count lower and higher than 150 × 10(3)/μl (p = 0.009). Bleeding and thrombotic complications are more frequent in hypoxemic CHD patients irrespective of platelet counts. Larger platelets, as reflected by an increased mean platelet volume, and the higher CRP concentration seen in hypoxemic CHD patients may explain to some extent the higher incidence of thrombotic events in hypoxemic patients.