Aggressive Strategy For Maintaining Antegrade Pulmonary Blood Flow During Bidirectional Glenn Procedure

OBJECTIVE-The bidirectional Glenn procedure(BDG)has become an effective palliative procedure and standard intermediate step toward total cavopulmonary connection(TCPC)for patients with functional single ventricle.Given the low rate of Fontan completion,an aggressive policy for maintaining antegrade pulmonary blood flow(AnPBF)during bidirectional Glenn procedure(BDG)was developed for the patients with functional single ventricle.This study investigated the outcomes of BDG and Fontan completion rate in China.METHODS-We retrospectively reviewed the clinical records of 420 patients who underwent BDG from January 2008 to December 2013.Forty-seven patients who underwent one and a half ventricle repair,five patients who received modified Blalock-Taussig shunt placement after BDG and seventy-four patients with pulmonary atresia were excluded.The remaining 294 patients with SV physiology were divided into two groups:Group 1(uncontrolled AnPBF,n=270),Group 2(controlled AnPBF,n=24).Pulmonary artery banding was performed owing to the high central venous pressure in Group 2.In Group 1,the 151 patients receiving BDG during 2008.1-2011.12 was further divided into Group DF(delayed Fontan completion)(n=109)and Group FC(Fontan completion)(n=42).All the additional systemic to pulmonary shunts were excluded and the major aortopulmonary collateral arteries were occluded in a hybrid operating room before BDG.In Group 1,the azygos vein was ligated and the main pulmonary artery was left intact.The azygos vein was left intact in Group 2.Pre-BDG cardiac catheterization was performed in all patients and pulmonary artery index(Nakata index)and mean pulmonary artery pressure were recorded.The early clinical outcomes included the surgical mortality,the pulmonary artery pressure,arterial oxygen saturation and the amount of the pleural drainage before discharge.Echocardiographic study was performed before discharge to assess ventricular function and atrioventricular valve regurgitation.During follow-up,the body weight,arterial oxygen saturation and the echocardiographic data were recorded.Cardiac catheterizations were recommended if the patients were suitable for TCPC completion.Statistical calculations were performed using SPSS 19.0.The Kaplan-Meier method and log-rank test were used for actuarial survival analysis.Binary logistic regression analyses were performed to investigate the relationship between various independent variables and PAB and aggravation of atrioventricular valve regurgitation.RESULTS There were 3 early postoperative deaths:2 patients died from pulmonary hypertension and subsequent heart failure in group 1,and 1 died from severe pneumonia in group 2.There were 9 late deaths during the follow-up(3 in group 4 and 0 in group 3).Actuarial survival rate did not significantly differ among various groups(p=0.51).The follow-up time was 39±20 months.Fontan completion rate was 16.3%and the average interval time was 2.2±1.1 years.There were no difference in TCPC completion rate(15.9%vs.20.8%,p= 0.42)and the interval time(2.3±1.1 vs.1.8±1.0 years,p=0.38)in Group 1 and 2.The mean pre-Glenn pulmonary artery pressure was 15±3.7mmHg in Group 1 and 19.1±5.9mmHg in Group 2(p<0.01).No difference in pulmonary artery pressures after BDG among two groups during the follow-up was observed.The arterial oxygen saturation was 90.2±3.4%in group 1 compared with 88.6±3.7%in group 2(p=0.063)after Glenn and maintained a higher level on follow-up.During the follow-up,Nakata index stayed in a higher range from 252±125 mm2/m2 to 277±129 mm2/m2(p=0.476)in group 1 and from 234±122 mm2/m2 to 223±87 mm2/m2(p=0.9)in group 2.Although no impaired heart function was observed among various groups,echocardiographic study revealed that increased ventricular end-diastolic diameter(25.5±8.5 vs.29.8±10.8mm,p=0.02)and aggravated atrioventricular valve regurgitation(1.6±1.1 vs.2.1±0.8,p=0,01)in Group 1.Logistic regression analysis indicated associated surgical procedures(atrioventricular valvuloplasty or TAPVC repair)were associated with the need for PAB and systemic right ventricle morphology was a risk factor for aggravation of valve regurgitation.The delayed Fontan completion didn't reduce the body weight gain and survival rate.Furthermore,in Group FC,the majority of the patients received TCPC at 24 months after BDG.Therefore,the arterial oxygen saturation was significantly increased in Group FC,while slightly decreased in Group DF after 24 months after BDG.CONCLUSIONS-Low Fontan-achievement rate was a critical issue in China.Although the patients with the delayed Fontan completion had acceptable survival rate and body weight gain,the uncontrolled AnPBF was associated with the ventricle enlargement and aggravation of valve regurgitation.The strategies to improve the Fontan completion rate in China should be explored and might benefit outcomes.