Assessment of cardiopulmonary bypass-induced platelet disorders using the Quantra Qplus system: the prospective...

Cardiac surgery with cardiopulmonary bypass (CPB) frequently results in haemostatic disturbances and perioperative bleeding. The Quantra® QPlus system measures platelet contribution to clot stiffness (PCS), a viscoelastic parameter reflecting platelet clot strength obtained under low-shear conditions. Evidence regarding its ability to detect CPB-induced platelet disorders (CPD) remains limited.

We conducted a single-centre prospective diagnostic accuracy study in patients undergoing elective cardiac surgery with CPB. The primary objective was to determine whether PCS could predict CPD. The composite primary endpoint was CPD, defined as postoperative thrombocytopenia (<100×10⁹ L^-1) or platelet dysfunction (prolonged prolonged collagen (COL)/adenosine diphosphate (ADP) closure time >100 s) on the PFA-200® in the absence of acquired von Willebrand syndrome.

One hundred patients were enrolled (median age 62 yr, 69% male). Procedures included coronary artery bypass grafting (49%), valve surgery (23%), and combined procedures, with a median CPB duration of 122 min. CPD occurred in 53 patients: 11 had thrombocytopenia and 52 exhibited prolonged COL/ADP closure time. PCS predicted CPD with modest discrimination (ROC-AUC 0.61, 95% confidence interval [CI] 0.50-0.72, P=0.048), with a threshold of 14.7 hPa providing 81% sensitivity and 43% specificity. PCS strongly predicted post CPB-thrombocytopenia (ROC-AUC 0.89, 95% CI 0.82-0.97, P<0.001) but was not predictive of platelet dysfunction (ROC-AUC 0.59, 95% CI 0.48-0.71, P=0.105).

Platelet contribution to clot stiffness poorly predicted cardiopulmonary bypass-induced platelet disorders after elective cardiac surgery. Although it reliably identified post-cardiopulmonary bypass thrombocytopenia and might serve as a point-of-care surrogate for platelet count, it does not detect cardiopulmonary bypass-induced platelet dysfunction.