Combined low-dose aspirin and warfarin anticoagulant therapy of postoperative atrial fibrillation following mechanical heart valve replacement.

The safety and efficacy of combined low dose aspirin and warfarin therapy in patients with atrial fibrillation after mechanical heart valve replacement were evaluated. A total of 1016 patients (620 females, mean age of 36.8±7.7 years) admitted for cardiac valve replacement and complicated with atrial fibrillation after surgery were randomly divided into study (warfarin plus 75-100 mg aspirin) or control (warfarin only) groups. International normalized ratio (INR) and prothrombin time were maintained at 1.8-2.5 and 1.5-2.0 times the normal values, respectively. Thromboembolic events and major bleedings were registered during the follow-up period. Patients were followed up for 24±9 months. The average dose of warfarin in the study and control groups was 2.91±0.83 mg and 2.88±0.76 mg, respectively (P>0.05). The incidence of overall thromboembolic events in study group was lower than that in control group (2.16% vs. 4.35%, P=0.049). No statistically significant differences were found in hemorrhage events (3.53% vs. 3.95%, P=0.722) or mortality (0.20% vs. 0.40%, P=0.559) between the two groups. Combined low dose aspirin and warfarin therapy in the patients with atrial fibrillation following mechanical heart valve replacement significantly decreased thromboembolic events as compared with warfarin therapy alone. This combined treatment was not associated with an increase in the risk of major bleeding or mortality.

Impact of peripherally established cardiopulmonary bypass on regional and systemic blood lactate levels.

BACKGROUND: To investigate blood lactate levels during and after peripherally established cardiopulmonary bypass (CPB). METHODS: In 86 patients (41 males, mean age 13.8 ± 7.2), CPB was established via femoral vein and artery cannulation for thoracoscopic closure of atrial (n=54) or ventricular septal defect (n=32). Arterial and venous blood lactate levels were measured from the cannulated limb during CPB, and from systemic circulation after CPB. RESULTS: The mean duration of CPB and cannulation of a lower extremity were 50.0 ± 10.5 min and 76.0 ± 18.5 min, respectively. The mean arterial lactate level measured from the systemic circulation remained unchanged during CPB (P>0.05). In patients with CPB for 3h or more, mean arterial lactate in the cannulated limb were higher than the baseline values (3.3 ± 0.5 vs 0.8 ± 0.2 mmol/L, P<0.05). In patients with more than 2h of CPB, mean venous lactate levels in the cannulated limb were also higher than the baseline values (3.4 ± 0.2 vs 1.1 ± 0.3 mmol/L, P<0.05). Within 6h after CPB, systemic arterial (3.0 ± 0.2 vs 0.8 ± 0.1 mmol/L, P<0.01) and venous lactate levels (6.5 ± 0.2 vs 1.0 ± 0.1 mmol/L, P<0.01) were higher than the pre-CPB values. CONCLUSIONS: Peripherally established CPB was associated with an arterial and venous lactate elevation in local and systemic circulation. The duration of CPB and lower limb cannulation appears to be related to the lactate elevation.

Effect of preoperational mechanical ventilation on short-term postoperative outcomes in patients with severe tetralogy of Fallot.

BACKGROUND: This study is designed to investigate the effect of preoperational mechanical ventilation on the short-term postoperative outcomes following corrective surgery for severe tetralogy of Fallot (TOF). METHODS: Ninety-two patients (58 males, mean age 20.5±8.5 months) with severe TOF were randomised into study and control groups. In the study group, mechanical ventilation was performed in PEEP/PRVC mode in the intensive care unit to correct blood gas imbalances for the corrective surgery. In the control group, preoperative oxygen supply was provided via face mask or nasal tubes. RESULTS: The postoperative mechanical ventilation time (14.3±1.9 vs 22.5±2.2h, p=0.02), intensive care stay (2.3±1.2 vs 4.7±1.1d, p=0.03) and duration for positive inotropic drug administration (2.5±1.1 vs 4.8±1.2d, p=0.04) in the study group were shorter than those in the control group. The postoperative capillary leak syndrome in the study group was lower than that in the control group (4.3% vs 23.9%, p=0.006). There was no statistically significant difference in the postoperative mortality between the study and control groups (2.1% vs 6.5%, p=0.606). CONCLUSIONS: Preoperational mechanical ventilation in patients with severe forms of TOF was associated with improved short-term outcomes following the corrective surgery. The effect of the preoperational ventilation on postoperative mortality requires further investigation.

Effect of captopril on pulmonary artery pressure following corrective surgery for tetralogy of fallot.

BACKGROUND: This study was designed to investigate the effect of captopril on systolic pulmonary arterial pressure (PAP) and circulating endothelin-1 (ET-1) following surgical repair of tetralogy of Fallot (TOF). METHODS AND RESULTS: Seventy-six consecutive patients were divided into captopril and control groups following successful repair of TOF. The captopril group was treated with oral captopril (0.2 mg/kg/day) for 12 months. Venous blood was taken before and after the surgery for the analysis of ET-1. Systolic PAP and ventricular function were assessed by Doppler echocardiography. In the control group, there was an increase in ET-1 and systolic PAP following the surgery (p < 0.05). In the captopril group, there was no significant increase in the systolic PAP and ET-1 during the 12-month follow-up. The PAP and ET-1 values in the captopril group were lower than those in the control group following the surgery (p < 0.05). CONCLUSIONS: Systolic PAP is elevated following the complete surgical repair of TOF. Increased circulating ET-1 may be responsible for the elevation of PAP. Captopril treatment prevents postsurgical increases in systolic PAP and circulating ET-1.

[An experimental study of recombinant human erythropoietin on the treatment of acute myocardial infarction in rats].

OBJECTIVE: To observe the treatment and it's mechanisms of rHu-EPO on acute myocardial infarction of SD rats in vitro and vivo. METHODS: Cardiomyocytes were isolated from neonatal Sprague-Dawley rats. Hypoxia condition and oxidative stress were used to induce apoptosis. rHu-EPO was added to the culture system. Apoptosis was assessed by using Hoechst 33258 dyeing. Apoptosis index (AI) was then calculated. Thirty two rats were divided into three groups including sham operation group (Sham), acute myocardial infarction group (MI) and treated group (MI + EPO). Acute myocardial infarction model was made by ligating the anterior descending coronary artery. rHu-EPO was administered i.p. in MI + EPO group at the dose of 5000 units/kg of body weight immediately after the ligation and the next six days. At the fourteenth day all animals underwent hemodynamic measurements and then executed, the samples were examined with hematoxylin and eosin (HE) stain, immunohistochemistry technique (Bcl-2, Bax) and TdT-mediated dUTP nick end labeling (TUNEL) dyeing. RESULTS: rHu-EPO significantly down-regulated the apoptosis of cardiomyocytes which underwent hypoxia or oxidative stress. In vivo experiment rHu-EPO protected the hemodynamic function of the rats from myocardial infarction and down-regulated the ratio of the positive cells for TUNEL and Bax. The ratio of the positive cells for Bcl-2 was up-regulated by rHu-EPO. CONCLUSION: These findings suggested rHu-EPO improve myocardial infarction by attenuating apoptosis. Potential mechanism is to up-regulated Bcl-2 expression and down-regulated Bax expression.

Thoracoscopic closure of ventricular septal defect in young children: technical challenges and solutions.

OBJECTIVES: To investigate the feasibility and safety of totally thoracoscopic repair of ventricular septal defects (VSDs) in young children. METHODS: VSD repair was conducted in 36 children (21 boys, mean age 2.5 ± 1.7 years, range 2-5, mean body weight 17.4 ± 2.1 kg) by a totally thoracoscopic approach. Cardiopulmonary bypass (CPB) was achieved peripherally. Through three port incisions in the right chest wall, pericardiotomy, atriotomy and VSD repair were performed under the direct view of a thoracoscopy. Forty patients who were treated with a traditional VSD closure through a sternotomy were selected as a control group. RESULTS: There was no statistically significant difference in age, sex or types of VSD between the study and control group (P > 0.05). In the study group, CPB was established through femoral vessels in 28 (77.8%) patients, and through both the right internal jugular vein and the femoral vessels in eight (22.2%). The aortic cross-clamp time (32 ± 6 vs 29 ± 3 min, P = 0.06) and CPB time (46 ± 11 vs 48 ± 4 min, P = 0.107) were similar between the study and control groups. However, the total operation time, mechanical ventilation time, intensive care stay and overall hospital stay in the study group were shorter than in the control group (P < 0.05). Transthoracic echocardiography 3 months after the operation showed no residual shunt in the ventricular septum. CONCLUSIONS: Thoracoscopic closure of VSDs in young children appears feasible and safe.