Repair of large ventricular septal defects in infants and small children

Outcomes of infants and children undergoing surgical repair of ventricular septal defect: a review of the literature and implications for research with an emphasis on pulmonary artery hypertension

BACKGROUND

Pulmonary vascular disease resulting from CHDs may be the most preventable cause of pulmonary artery hypertension worldwide. Many children in developing countries still do not have access to early closure of clinically significant defects, and the long-term outcomes after corrective surgery remain unclear. Focused on long-term results after isolated ventricular septal defect repair, our review sought to determine the most effective medical therapy for the pre-operative management of elevated left-to-right shunts in patients with an isolated ventricular septal defect.

METHODS

We identified articles specific to the surgical repair of isolated ventricular septal defects. Specific parameters included the pathophysiology and pre-operative medical management of pulmonary over-circulation and outcomes.

RESULTS

Studies most commonly focused on histologic changes to the pulmonary vasculature and levels of thromboxanes, prostaglandins, nitric oxide, endothelin, and matrix metalloproteinases. Only 2/44 studies mentioned targeted pharmacologic management to any of these systems related to ventricular septal defect repair; no study offered evidence-based guidelines to manage pulmonary over-circulation with ventricular septal defects. Most studies with long-term data indicated a measurable frequency of pulmonary artery hypertension or diminished exercise capacity late after ventricular septal defect repair.

CONCLUSION

Long-term pulmonary vascular and respiratory changes can occur in children after ventricular septal defect repair. Research should be directed at providing an evidenced-based approach to the medical management of infants and children with ventricular septal defects (and naturally all CHDs) to minimise consequences of pulmonary artery hypertension, particularly as defect repair may occur late in underprivileged societies.

Clinical implication of main pulmonary artery Windkessel size after banding operation

BACKGROUND

The Windkessel model, proposed in 1895 by O. Frank, successfully explained systemic and abnormal pulmonary hemodynamics of congenital cardiac defects. The model is essentially a functional one and describes only hemodynamics, not anatomical or geographic structures. Because pulmonary arterial banding (PAB) adds a substantial resistance proximal to arterioles, it provides an ideal anatomical structure of the Windkessel model, namely, an elastic reservoir of much dilated main pulmonary artery (mPA) followed by a substantial artificial resistance of banding.

METHODS

The pulmonary artery (PA) Windkessel size (WS) of 10 patients, several months to years after PAB, were estimated both in peak systole (WSs) and minimum diastole (WSd), as the product of Windkessel compliance and proximal to distal pulmonary arterial pressure difference at each cardiac phase. They were compared to cineangiogram-determined corresponding volumes (Vs, Vd) of PA proximal to the band or mPA.

RESULT

WSs and WSd correlated well with Vs and Vd, respectively, with the correlation coefficient of 0.91 and 0.62, indicating that the Windkessel in these patients corresponds to mPA. Among five patients whose resistance at the band comprised more than half of the whole PA resistance, the coefficients proved even better.

CONCLUSION

Much bigger secondarily developed Windkessel, as placed proximal to the band on top of a substantial resistance at PAB, contributed much to alleviate the stress downstream at the periphery caused by greatly increased systolic stroke volume into mPA in these cardiac defects.

[Results of the surgical closure of ventricular septal defects of various ages: report of 30 cases]

OBJECTIVE

To appreciate short and midterm results of patients after surgical closure of the ventricular septal defect.

MATERIAL AND METHODS

The study is retrospective and took place in the department of cardiovascular surgery "B", Ibn-Sina hospital, Rabat, Morocco. Between 1995 and 2005, 30 patients underwent a surgical closure of ventricular septal defect. Eighteen patients (60%) were males and twelve (40%) were females with a mean age of 10 years (18 months-36 years). Seven patients (23%) were older than 16 years. All of ventricular septal defects were type 2, unique and most of them perimembranous (70%). Four patients (13%), were older than 16 years, had a significant aortic insufficiency that has dictated the aortotomy for ventricular septal defect repair. The surgical approach through the right atriotomy was sufficient for complete repair in 22 patients (73%). Closure of the defect has been done using a pericardial autologous patch in 28 patients (93%).

RESULTS

No operative mortality was observed. The mean follow-up was five years. Eight patients (26%) had a residual ventricular septal defect that progressed to spontaneous closure. Two patients (6%) had a residual pulmonary hypertension and two others a moderate aortic regurgitation. The four patients were older than 16 years. Echocardiography showed a significant reduction in left ventricular dimension and systolic pulmonary artery pressure. At last follow-up, 87% of the patients were in NYHA class 1.

CONCLUSION

This study demonstrates that surgical closure of ventricular septal defect ensures a good outcome in short and midterm. Nevertheless, the risk of delayed complications justifies long-term and regular follow-up.

Outcome of ventricular septal defect repair in a developing country

OBJECTIVES

To examine the impact of nutrition and lung infection on outcome early after ventricular septal defect (VSD) repair in infants in a developing country.

STUDY DESIGN

One hundred consecutive infants (age, 7.4 +/- 3.3 months) with large VSD(s) who underwent surgical repair at one institution in South India from July 1998 to June 2000 were analyzed. Primary outcome variables were postoperative death, duration of mechanical ventilation, intensive care unit (ICU) stay, and hospital stay. Preoperative variables analyzed included age, weight and length Z scores, and lung infection.

RESULTS

Preoperative nutrition was poor (weight Z score, -2.8 +/- 1.3), and 25 patients had pneumonia. Six patients died after repair. No preoperative variable was associated with death. Mechanical ventilation, ICU stay, and hospital stay were longer for younger patients (r (s) for ventilation, -0.23, P =.02; for ICU stay, -0.33, P <.001; for hospital stay, -0.27, P =.007) and for those with preoperative pneumonia (median ventilation duration, 46 vs 24 hours, P <.001; median ICU stay 7 vs 4 days, P <.001; median hospital stay 10 vs 7 days, P =.001). Preoperative weight and length Z scores were not associated with any outcome variable.

CONCLUSIONS

Poor nutritional status, preoperative pneumonia, and age do not increase mortality rates after VSD repair. Repair of large VSDs should not be delayed because of these preoperative characteristics.

Pulmonary artery banding: results and current indications in pediatric cardiac surgery

The results of pulmonary artery banding in 144 patients seen from 1971 to 1984 were reviewed. Age ranged from 1 week to 4 years (median, 8 weeks) and weight, from 1.1 to 16 kg (median, 4 kg). The patients were divided into three major groups: Group 1, defects without mixing disorders (ventricular septal defect, double-outlet right ventricle [DORV], atrioventricular septal defect); Group 2, defects with mixing disorders (transposition of the great arteries, DORV, single ventricle, tricuspid atresia); and Group 3, miscellaneous (mitral atresia, left ventricular hypoplasia, truncus complex). The diagnostic group influenced survival (p = 0.0035). In Group 1, 88.8% survived, but only 64.9% survived in Groups 2 and 3 combined. The presence of patent ductus arteriosus or coarctation of the aorta had no effect on survival (p = 0.61 and p = 0.7, respectively). The clinical condition at thirty days after pulmonary artery banding was good in 35.1% and fair in 46.9% of the patients. When the data were divided into the three periods 1971 through 1974, 1975 through 1979, and 1980 through 1984, which included 28, 49, and 67 patients, respectively, a significant improvement in survival was observed from the early (64.3%) to the late period (92.5%) (p = 0.0009). Patients weighing less than 4 kg had a significantly lower survival in the period 1971 through 1974 (37.5% versus 91.67%). No significant difference in survival was detected in the late period, 1980 to 1984 (90% versus 94.6%), between patients weighing less than and those weighing more than 4 kg. Pulmonary artery banding is clinically satisfactory in small infants and children with complex anomalies.

Predictors of postoperative ventricular dysfunction in infants who have undergone primary repair of a ventricular septal defect

By means of postoperative radionuclide angiography we identified a subset of infants undergoing primary repair of their ventricular septal defects (VSD) who had postoperative morbidity and ventricular dysfunction. Twenty-three consecutive infants undergoing repair of an uncomplicated VSD were studied. Radionuclide-determined postoperative ventricular dysfunction (VD), as defined by a left ventricular ejection fraction less than 0.30 2 to 4 hours after surgery, was correlated with clinical signs of postoperative morbidity. Six patients developed postoperative VD. Clinical correlates of VD included the use of postoperative inotropic support, increased number of postoperative intensive care days, and a low growth rate 3 months postoperatively. Potential predictors of VD were evaluated. A preoperative pulmonary-to-systemic blood flow ratio (Qp/Qs) greater than 3.0 and a pulmonary-to-systemic vascular resistance ratio (Rp/Rs) less than 0.20, taken in combination, gave a positive predictive value for VD of 100%. It is concluded that the preoperative Qp/Qs and Rp/Rs can be used to predict those infants at risk for postoperative morbidity following repair of their VSD.

Long-term results in isolated ventricular septal defect surgically repaired after age 10. Comparison with the natural course in similarly-aged patients

In a consecutive series, 125 patients with isolated ventricular septal defect (VSD) and age 10 or more were observed until death or beyond the age of 30 (31-73) years. Reinvestigation was performed after a mean observation time of 15 (4-21) years. Among the 41 patients who primarily underwent surgery (group 1) there were four postoperative deaths--three patients with severe aortic insufficiency and one with systemic pulmonary artery pressure. Surgery was not initially regarded as indicated in 70 patients with small defects (group 2). The remaining 14 patients were judged to be inoperable (group 3). The long-term mortality was 5% in group 1, 9% in group 2 and 71% in group 3. At the reinvestigation, the pulmonary artery pressure was significantly higher than the initial level in group 2 and significantly lower than that level in group 1. As compared with the surgically treated patients, group 2 showed higher incidence of valvular lesions (22% v. 14%) and of bacterial endocarditis (4.3% v. 2.7%), but not to statistically significant level. Spontaneous closure occurred in 6% of the group 2 cases. Residual defects were found in 34% of group 1, but were small. The intergroup differences, though of minor degree, favour surgical treatment, and patients with significant shunt should be recommended operation.