Two-ventricle Repair Research Articles

Morphometric Analysis of Unbalanced Common Atrioventricular Canal Using Two-Dimensional Echocardiography

Objectives. This study was designed to define morphometric echocardiographic variables of unbalanced common atrioventricular canal (CAVC) that could aid in appropriate referral for surgical repair.Background. Unbalanced CAVC has a high surgical mortality rate. This may be secondary to inappropriate referral of some patients for two-ventricle repair (closure of septal defects) instead of single-ventricle repair (Norwood palliation and Fontan operation).Methods. The echocardiograms of 103 patients with CAVC were retrospectively reviewed. In the subcostal left anterior oblique view, the area of the atrioventricular (AV) valve aportioned over each ventricle was measured, and an AV valve index (AVVI) was calculated as left/right valve area. The ventricular cavity ratio between the two ventricles was estimated as left ventricular length times width divided by right ventricular length times width. These variables were correlated with surgical referral and outcome.Results. Patients previously categorized as having balanced CAVC all had AVVI >0.67 (n = 77). Of the patients with unbalanced CAVC (n = 26), 11 had ductal-dependent circulation and underwent Norwood palliation (AVVI 0.21 ± 0.13, mean ± SD), and 15 had two-ventricle repair (AVVI 0.51 ± 0.12, p < 0.0001). Of these 15 patients, 9 have survived, with no difference in mean AVVI between survivors and nonsurvivors (0.52 ± 0.11 versus 0.49 ± 0.13, p = 0.72). For all 103 patients, AVVI correlated with ventricular cavity ratio. However, of the unbalanced CAVC group who underwent two-ventricle repair, three nonsurvivors had a discrepancy between AVVI and ventricular cavity ratio (low AVVI but normal ventricular size). A large ventricular septal defect was present in all six nonsurvivors but in only four of nine survivors (p < 0.05).Conclusions. Echocardiographic morphometry is useful in defining unbalance in CAVC. If AVVI is <0.67 in the presence of a large ventricular septal defect, a single-ventricle approach to repair should be considered.

Bidirectional Glenn Shunt for Complex Cyanotic Congenital Heart Disease

The bidirectional Glenn Shunt has been advocated for definitive or staged palliation of patients with a functional single ventricle and decreased pulmonary blood flow who are unsuitable for a Fontan operation. Between April 1990 and July 1994, 86 patients underwent bidirectional Glenn operation at the All India Institute of Medical Sciences in New Delhi. This operation was performed electively in 73 patients (group I), as a take-down for Fontan failure in 10 patients (group II), and to complement a two-ventricle repair in 3 patients in whom the right ventricle or the tricuspid valve was inadequate to handle the entire systemic venous return (group III). Fifty-five other procedures were performed in addition to the cavopulmonary shunt. The mean ICU stay was 2 days. There were 5 early deaths in group I, 6 in group II, and none in group III. Mean oxygen saturation at the time of discharge was 84.2% on room air. Follow-up ranged from 3 to 51 months. The bidirectional Glenn shunt was definitive palliation in 9 patients with azygos or hemiazygos continuation of the inferior vena cava. In the remaining patients, a corrective procedure is planned only if there is evidence of failure of palliation or ideal criteria for the Fontan procedure are met. Only 3 patients from group I have therefore undergone subsequent conversion to a Fontan circulation. The bidirectional Glenn shunt provides excellent relief of cyanosis, does not volume load the heart, and possibly lowers the risk of a subsequent Fontan operation. Timely take-down of a failed Fontan procedure is imperative for successful salvage.

Surgical management of neonatal coarctation

Between 1983 and 1994, 307 consecutive neonates underwent coarctation repair by a single surgical technique: extended end-to-end anastomosis. Mean age at operation was 13 ± 8 days. Isolated coarctation was present in 95 patients (group 1), 102 patients had associated ventricular septal defect (group 2), and 110 patients had associated complex intracardiac lesions (group 3). Aortic arch hypoplasia was present in 81% of the patients (62% in group 1 versus 85% in group 2 and 93% in group 3: p < 0.001). In 271 patients, the aortic arch reconstruction was performed via a left thoracotomy with normothermia (100% of group 1, 95% of group 2, and 72% of group 3); in the other 36 patients, undergoing one-stage repair or palliation of the associated lesion, it was performed via a midline sternotomy during a short period of deep hypothermia and circulatory arrest (5% of group 2 and 28% of group 3). Pulmonary artery banding was performed in 94 patients. Spontaneous ventricular septal defect closure was observed in 39% of the patients of group 2 operated on via thoracotomy. Early mortality rates in groups 1 (2%) and 2 (2%) were significantly lower than in group 3 (17%) ( p < 0.001). There were 29 late deaths, all related to associated cardiac lesions or their subsequent repair. The overall total mortality was 16.9%. In group 3 this rate was significantly higher in patients undergoing two-stage procedures (47%) than in those undergoing one-stage repair (23%) ( p < 0.05). All but 14 survivors were followed up for a mean of 61 ± 36 months. Actuarial survivals at 10 years were 98% in group 1, 94% in group 2, and 60% in group 3. The recoarctation rate was 9.8%, leading to 21 reoperations and three angioplasties without mortality. Patients with a more extended or severe form of aortic arch hypoplasia had a significantly higher risk of recoarctation ( p < 0.001). Actuarial freedom from reoperation for recoarctation at 10 years was 93%. The findings of this study suggest that extended end-to-end anastomosis provides an adequate and safe repair of neonatal coarctation. Low recoarctation rate, owing to effective relief of the obstruction created by aortic arch hypoplasia and to complete resection of ductal tissue, freedom from major morbidity, and feasibility via both lateral and anterior approaches are the main advantages of the extended end-to-end anastomosis. Mortality is mainly dependent on the complexity of the cardiac associations. Successful management of the majority of the neonates with coarctation and associated ventricular septal defect is possible with repair of coarctation alone. One-stage repair of neonatal coarctation and associated complex heart defects (with indication for two-ventricle repair) by means of an anterior approach provides a better outcome than a two-stage repair. (J T HORAC C ARDIOVASC S URG 1995;109:663-75)

The Norwood operation and subsequent Fontan operation in infants with complex congenital heart disease

From April 1987 to September 1993, 60 infants underwent a Norwood operation for complex congenital heart disease including hypoplastic left heart syndrome ( n = 41), ventricular septal defect and subaortic stenosis with aortic arch interruption/severe coarctation ( n = 7), complex single right ventricle with subaortic stenosis ( n = 8), critical aortic stenosis with endocardial fibroelastosis ( n = 2), and malaligned primum atrial septal defect with coarctation ( n = 2). Age at operation ranged from 1 day to 3.9 months (mean 9 days, median 3.5 days). The operative mortality (< 30 days) was 33% (20 patients). Late mortality was 17% (10 patients). Nine of the 20 (45%) operative deaths occurred during the first 2 days after the operation as a result of sudden hemodynamic instability. All four infants with premature closure of the foramen ovale had pulmonary lymphangiectasia and died of pulmonary failure. Seven operative deaths have occurred in 36 patients since 1990 (19%); in the past 2 years, no operative deaths have occurred in 22 patients. Overall, there are 30 long-term survivors (50%). Twenty-one of these 30 infants have undergone a two-stage repair with a modified Fontan operation at 7.3 to 27.6 months of age (mean 18.1 months) with no mortality. Six patients have entered a three-stage repair strategy by undergoing a hemi-Fontan procedure at 6.8 to 23.0 months (mean 8.8 months) with no mortality, and two of these patients have now had their modified Fontan operation at 23.0 to 46.7 months of age with no mortality (four are still awaiting surgery). Two patients have undergone a two-ventricle repair with a Rastelli procedure, with no mortality at 7.4 and 14.1 months of age. Early in our experience, infants undergoing the Norwood operation had a high early mortality most often related to sudden hemodynamic instability. After we instituted a protocol that adds carbon dioxide to the inspired gas during postoperative mechanical ventilation, the postoperative course became more stable and there have been no operative deaths. In summary, the operative mortality for the Norwood operation continues to improve. A subsequent Fontan operation can be performed with excellent clinical results. (J T HORAC C ARDIOVASC S URG 1995;109:654-62)

721-1 Percutaneous Balloon Dilation as Initial Treatment for Critical Aortic Stenosis. Results Up to 8.3 Years Follow-up In 46 Consecutives Neonates

The purpose of this study is to report our results with balloon dilation (BD) of critical aortic stenosis (AS) in neonates. From 1985 to ‘91, 46 consecutive babies &lt; 33 days of age had BD for critical AS. The median age was 5 days, and the mean weight was 3.2 kg; 41 (89%) was in congestive heart failure (CHF) or shock, 33 (80%) intubated. Associated cardiac abnormalities were present in 42 (91%). The BD, performed retrograde in 43 (umbilical artery 23, femoral artery 20), was completed in all, and with success in 41 (89%). The final balloon to aortic annulus ratio was 0.91 ± 0.05. The overall mortality was 35% (11 early and 5 late deaths 1.6 to 17 mos of follow-up). Of these 16, 4 were considered related to BD, and 12 to associated left-sided lesions. All babies who had BD via femoral artery had pulse loss, and anti-thrombotic therapy restored pulses in 7 (35%). Significant aortic regurgitation (AR) post-BD was observed in 5 (11%) babies. An anatomic risk factor score for two-ventricle repair(Rhodes et al, 1991) was retrospectively measured, and 13 (38%) babies had a score ≥ 2 (critical AS with 2 or more associated left-sided obstructive lesions; high mortality). No neonate with an anatomic score ≥ 2 survived longer than 4 mos, except 1 who underwent successful Norwood operation. In univariante analysis, an age of &lt; 3 days, a presentation in CHF or shock, and an anatomic score ≥2 were found to be related to mortality, but in a multivariante analysis, only the anatomic score was significant (p = 0.001). Reintervention was undertaken by 1 month in 22%, by 4 mos in 30%, and by 88 mos in 41%; the main indication was AS. At follow-up of 1.4 to 83 yrs (4.3 ± 1.8yrs), 30 (65%) were alive, and the clinical status was considered excellent or good in 90%. No child had leg length discrepancy. At Doppler study, a maximum gradient &gt;50 mmHg was found in 10 (33%), and significant AR was present in 4 (13%). when no more than 1 associated left-sided obstructive lesion is present. BD for critical AS is effective; at 8.3 yrs of follow-up, the probability of being alive is 88%, and of being free from reintervention is 59%.

Outcomes in neonatal pulmonary atresia with intact ventricular septum A multiinstitutional study

A total of 171 neonates with pulmonary atresia and intact ventricular septum were entered into a prospective multiinstitutional study between January 1, 1987, and January 1, 1991. Treatment was not assigned randomly but was selected by the responsible physicians. The Z-value (standard deviation units) of the diameter of the tricuspid valve was less than -2 in 52% of patients and less than -4 in 26%; it was highly correlated with right ventricular cavity size (which was small in 90% of patients and was severely reduced in 54%). Coronary artery-right ventricular fistulas were present in 45% of patients, and right ventricular dependency was severe in 9%; diameter (Z-value) of the tricuspid valve was negatively correlated (P < 0.0001) with the prevalence of both. Survival was 81% at 1 month after the first intervention and 64% at 4 years; the hazard function (instantaneous risk of death) declined rapidly after the initial procedure but remained appreciable for 24 months. Multivariable analysis showed small diameter of the tricuspid valve, severe right ventricular coronary dependency, birth weight, and the date and type of initial procedure to be risk factors for time-related death. Subsequent procedures were performed in 51% of patients. Among patients undergoing an initial procedure that did not include a systemic-pulmonary artery shunt, only 49% did not receive a shunt in the subsequent 1 month; small size of the tricuspid valve was the only risk factor for receiving the subsequent shunt. Ninety-eight percent of living patients whose initial procedure did not include a transannular patch were free of a subsequently placed transannular patch within 1 month, but only 45% were free of it 3 years later; no risk factors were identified. Eighteen percent of living patients had received a one-ventricle repair within 3 years, and 32% had received a two-ventricle repair; the remainder (50%) had incompletely separated pulmonary and systemic circulations. The only patient-specific risk factor for not receiving a two-ventricle repair was the Z-value of the tricuspid valve.