NPPB and diabetes mellitus: Among these, age (P < 0.001), history of hypertension (P = 0.023), history of diabetes (P = 0.006), preoperative BNP levels (P = 0.012), preoperative LVEF (P = 0.025), and the number of postoperative complications (P = 0.036) were all significantly associated with poor cardiac function improvement at 3 months, identifying them as major risk factors affecting cardiac function recovery (Table 4).