Late results after surgical closure of ventricular septal defect in children

Late surgical ventricular septal defect closure in a low middle-income country setting: a case series

BACKGROUND

Ventricular septal defect (VSD) is the commonest type of congenital heart lesion accounting for up to 40% of congenital heart defects. Well timed VSD closures are reported to yield excellent long-term outcomes. Late surgical VSD closures, particularly from the developing countries, are infrequently reported.

CASE PRESENTATION

We report three cases of African children aged between 13 and 14 years who had late VSD presentations. They reported complaints of growth failure and recurrent respiratory infections since early infancy which necessitated frequent visits to primary health care facilities. They were found to have large ventricular septal defects by thoracic echocardiography. Diagnostic cardiac catheterization was done to all three patients to rule out irreversible pulmonary hypertension. After promising cardiac catheterization findings, they all underwent successful surgical VSD repair with good early outcomes.

CONCLUSION

VSD surgical closure is ideal in children below 2 years, however, it can be done in children who present at advanced age despite being considered high risk patients. All three of our patients who presented late had successful surgical VSD repairs with promising immediate outcome. The role of genetics in the protection against developing irreversible pulmonary vascular disease in these patients is a possible area for future studies.

Pulmonary blood flow and pulmonary hypertension: Is the pulmonary circulation flowophobic or flowophilic?

Increased pulmonary blood flow (PBF) is widely thought to provoke pulmonary vascular obstructive disease (PVO), but the impact of wall shear stress in the lung is actually poorly defined. We examined information from patients having cardiac lesions which impact the pulmonary circulation in distinct ways, as well as experimental studies, asking how altered hemodynamics impact the risk of developing PVO. Our results are as follows: (1) with atrial septal defect (ASD; increased PBF but low PAP), shear stress may be increased but there is little tendency to develop PVO; (2) with normal PBF but increased pulmonary vascular resistance (PVR; mitral valve disease) shear stress may also be increased but risk of PVO still low; (3) with high PVR and PBF (e.g., large ventricular septal defect), wall shear stress is markedly increased and the likelihood of developing PVO is much higher than with high PBF or PAP only; and (4) with ASD, experimental and clinical observations suggest that increased PBF plus another stimulus (e.g., endothelial inflammation) may be required for PVO. We conclude that modestly increased wall shear stress (e.g., ASD) infrequently provokes PVO, and likely requires other factors to be harmful. Likewise, increased PAP seldom causes PVO. Markedly increased wall shear stress may greatly increase the likelihood of PVO, but we cannot discriminate its effect from the combined effects of increased PAP and PBF. Finally, the age of onset of increased PAP may critically impact the risk of PVO. Some implications of these observations for future investigations are discussed.

Long term results after operative treatment of isolated ventricular septal defect in adolescents and adults

A series of 125 consecutive patients with isolated ventricular septal defect (VSD) aged 10 or over, were followed until death or beyond the age of 30 (31-73) years. A prospective restudy was performed after a mean follow-up of 15 (3-21) years. Forty-one patients (group 1) were treated with surgical repair of VSD at a mean age of 23 (10-51) years, and early mortality was 10%, i.e. 3 with severe aortic insufficiency and one with systemic pulmonary artery pressure. Surgery was initially not regarded indicated in 70 patients with small defects (group 2). A further 14 patients were judged inoperable (group 3). Long-term mortality was 5% in group 1, 9% in group 2 and 71% in group 3. When restudied, group 2 patients had significantly higher (p less than 0.01) and group 1, lower (p less than 0.01) pulmonary artery pressures than initially. A moderate deterioration in NYHA-rating was noted in group 2 (p less than 0.05) vs. a slight improvement in group 1 (p less than 0.05). The non-operated patients had a higher incidence of valvular lesions (19% vs. 13%) and bacterial endocarditis (4.3% vs. 2.7%) than the operated but not to a statistically significant level. Spontaneous closure was 6% in group 2 whereas mostly small residual defects were found in 34% of the operated. Patients with uncomplicated VSDs (absence of valvular lesions or coronary heart disease) had subnormal exercise tolerance as judged from a standardized ergometer bicycle test. These patients also had impaired left ventricular function based upon haemodynamic studies during moderate supine exercise. No major differences were noted between groups 1 and 2, but operated patients with residual VSDs tended to have the poorest cardiac performance. Non-cardiac disease represented only a minor problem and no significant differences in psychosocial function were observed between groups 1 and 2. Only 50% in group 1 and 60% in group 2 attended a regular medical clinic. Antibiotic prophylaxis had only been practiced by 50% in both groups. Although small, but differences between groups 1 and 2 favour surgery. This must be regarded as a positive result of surgical treatment since those operated on had basically larger and thus more severe defects than the others. In view of the very low operative risk associated with modern surgical technique one should direct patients with significant shunts to operative treatment.

Exercise after surgical repair of congenital cardiac lesions

Congenital heart defects arise in approximately 1% of all live births, independent of ethnic and geographical considerations. With the development of new surgical procedures and current technologies a large number of these heart lesions can be surgically corrected in infancy. In the majority of cases patients evaluated some 10 to 20 years after surgery are asymptomatic and can lead a normal life. Despite their satisfactory clinical outcome patients may, nevertheless, show an abnormal pattern of physiological responses when submitted to dynamic exercise. This paper reviews the scientific literature concerning the exercise capabilities and the cardiorespiratory adjustments to exercise in patients surgically corrected for 4 of the most common congenital heart lesions: isolated atrial septal defect, isolated ventricular septal defects, pulmonary stenosis and tetralogy of Fallot. The maximal exercise tolerance of postoperative congenital heart defect patients may usually be related to: (a) the age of the patients at the time of surgery; (b) the severity of the lesions remaining after surgery; and (c) the age of the patients at the time of investigation. Although normal maximal exercise capabilities may be found in a good number of patients operated for either of the 4 lesions considered, this does not imply normal exercise haemodynamics. A general observation made in these 4 groups of patients is that of a subnormal exercise cardiac output which may or may not be fully compensated by an increase in peripheral oxygen extraction. The limitation in exercising cardiac output may, in turn, be attributed to either a subnormal stroke volume or a limitation in the chronotropic response to exercise or a combination of both factors. Residual pulmonary stenosis, increased pulmonary vascular resistance, increased myocardial stiffness are all factors that may contribute to the cardiac output limitation. A thorough explanation of underlying causes for the abnormal haemodynamic response to exercise, however, still remains to be provided.

Exercise induced pulmonary vasoconstriction

Pulmonary vascular resistance normally falls or remains unchanged during exercise. Seven children with pulmonary hypertension were exercised during cardiac catheterisation after operative correction of ventricular septal defect (6) and truncus arteriosus (1). Except for the presence of moderate pulmonary hypertension, resting haemodynamics in these seven children were similar to those of normal children of equal age, but during exercise the postoperative patients showed a rise rather than a fall (+2% vs -18%) in total pulmonary vascular resistance. Two of the seven children had a substantial increase in pulmonary arteriolar resistance during exercise (from 509 to 715 dyne s cm-5 in one patient and from 606 to 828 dyne s cm-5 in the other). These two patients did not differ from normal children in respect of arterial or mixed venous oxygen saturations or of pH with exercise, nor was left atrial pressure related to the rise in pulmonary resistance. These two patients, however, had only a small rise in cardiac output during exercise (6.8% and 43.1%) in spite of a substantial increase in oxygen consumption (121% and 373%). One of the patients with exercise-induced pulmonary vasoconstriction had an 82% increase in resting pulmonary vascular resistance over a five year period subsequent to her first exercise study. Analysis of these data, and those previously reported, suggests that exercise induced pulmonary vasoconstriction may occur in 10 to 25% of patients who survive correction of certain congenital cardiac defects. The vasoconstriction cannot be attributed to abnormal changes in blood gases or left atrial pressure, and may be an early sign of progressive pulmonary hypertension.

Ventricular dynamics after surgical closure of VSD

Twenty patients varying in age between 5 and 20 years at the time of surgical closure of VSD were studied 2 to 9 years postoperatively. Ventricular function was studied by echocardiography and measurement of systolic time intervals for the left and right ventricles and the findings were related to clinical and haemodynamic results of operation. The VSD was closed in all instances and the haemodynamic situation was normalized in all but 2 patients who had persisting pulmonary vascular disease. Right bundle branch block (RBBB) was recorded in 11 instances and in 5 there was an associated left axis deviation (LAD), suggesting left anterior hemiblock. LAD occurred as an isolated anomaly in another 2 patients. The heart size was within normal limits in all the patients. Abnormal septal motion (ASM) was recorded in 13 of the 20 patients, but other echocardiographic analyses, such as LV end-diastolic dimension, left atrial/aortic root ratio, posterior wall velocity index and maximal endocardial velocity, were all within predicted normal limits. There was an almost uniform prolongation of both left and right pre-ejection periods. left and right ejection period as a rule remained normal and gave an increased PEP/ET ratio, indicating the presence of postoperative ventricular dysfunction also in instances with complete normalization of the haemodynamic situation. Suggested background mechanisms for these findings are the frequent occurrence of conduction defects postoperatively, the likelihood of altered ventricular compliance and possibly also as a cause of ASM postoperative presence of an opened pericardial sac.