Table 3: Postoperative echocardiographic results n = 484 Predischarge mitral valve gradient (mmHg) 3.46 ± 1.43 Predischarge heart rate (min−1) 80 ± 15 Predischarge stroke volume (ml)a 74 (58–93) Predischarge cardiac index (l/m2)a 5.7 (4.6–7.4) Predischarge haemoglobin value (mmol/l) 6.4 ± 0.8 Data are presented as means ± standard deviations and medians (IQR). a Available for ≥90% of patients. IQR: interquartile range.