HES 130/0.4 significantly solution will not affect on coagulation and blood loss in patients medicated with antiplatelet agents prior to off-pump coronary bypass surgery (OPCAB).

Inclusion Criteria:

• Eighty patients undergoing OPCAB, who were exposed to anti platelet agents until 5 days prior to surgery were randomly allocated to infuse HES 130/0.4 up to 30 ml/kg and followed crystalloid infusion or infuse crystalloid only during perioperative period,

Exclusion Criteria:

Patient who has

• Valvular disease of heart
• MI within 3 months,patient under 40% of left ventricle preoperative output
• left main artery stenosis
• anemia (hemoglobin < 12 g/dl), coagulopathy (Platelet < 100/nl, activated partial thromboplastin time, aPTT) > 80sec, serum creatinine > 1.2 mg/dl, respiratory disease(asthma, COPD, PaO2 < 70 mmHg, pulmonary hypertension or pulmonary edema, etc)
• not consented to this trial