Ventricular septal defect: results after repair in infancy

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.

Growth after ventricular septal defect repair: does defect size matter? A 10-year experience

AIM

To evaluate whether the ventricular septal defect (VSD) size, along with the degree of preoperative growth impairment and age at repair, may influence postoperative growth, and if VSD size can be useful to identify children at risk for preoperative failure to thrive.

METHODS

Sixty-eight children submitted to VSD repair in a Brazilian tertiary-care institution were evaluated. Weight and height measurements were converted to Z-scores. Ventricular septal defect size was normalized by dividing it by the aortic root diameter (VSD/Ao ratio).

RESULTS

Twenty-six patients (38%) had significantly low weight-for-height, 10 patients (15%) had significantly low height-for-age and 13 patients (19%) had both conditions at repair. Catch-up growth occurred in 82% of patients for weight-for-age, in 75% of patients for height-for-age and in 89% of patients for weight-for-height. Weight-for-height Z-scores at surgery were significantly lower in patients who underwent repair before 9 months of age. The VSD/Ao ratio did not associate with any other data. On multivariate analysis, weight-for-age Z-scores and age at surgery were independent predictors of long-term weight and height respectively.

CONCLUSION

The VSD/Ao ratio was not a good predictor of preoperative failure to thrive. Most patients had preoperative growth impairment and presented catch-up growth after repair. Preoperative growth status and age at surgery influenced long-term growth.

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.

Aortic regurgitation associated with ventricular septal defects in adults. Clinical course, haemodynamic, angiographic and echocardiographic findings

In 125 consecutive patients, aged greater than or equal to 10 years (mean 27, range 10-64), evaluated for isolated ventricular septal defects (VSD) the initial prevalence of aortic regurgitation (AR) was 12/125. Forty-one patients were operated on, and post-operative mortality was 3/6 in patients operated on for VSD and AR and 1/35 in those operated on for VSD alone. All but one of the patients have been followed until death or beyond the age of 30 years (mean 42, range 31-73) and a prospective restudy has been performed after a mean observation time of 15 years (range 4-21). The incidence of new cases of AR arising during this period was 10/111. AR was severe in 5 cases (one died from heart failure), moderate in 1 and mild in 4. Surgical repair of AR and VSD was performed in 3 cases. Common characteristics of patients who developed AR were advanced age, male sex, history of bacterial endocarditis, small subaortic VSDs and tricuspid aortic valves without prolapse. Echocardiography revealed larger aortic root diameter (p less than 0.001), increased eccentricity factor (p less than 0.001) and increased left ventricular dimensions (p less than 0.02) in those with complicating AR. AR in adults with VSD may have an unpredictable clinical course; it may be difficult to assess clinically and the need for close clinical control is emphasized. Echocardiography remains of considerable value in selected cases.

Is complete heart block after surgical closure of ventricular septum defects still an issue?

BACKGROUND

A serious complication after surgical closure of ventricular septal defect (VSD) is complete heart block. In this retrospective study, we reviewed the incidence of complete heart block after surgical closure of a VSD at Great Ormond Street Hospital from 1976 to 2001 to identify any particular anatomic features that still predisposed patients to surgically-induced complete heart block and to provide anatomic guidelines to avoid this in future.

METHODS

Data were extracted from our local database for patients having (1) isolated VSD or VSD in the setting of (2) tetralogy of Fallot with pulmonary stenosis or (3) tetralogy of Fallot with pulmonary atresia; (4) absent pulmonary valve syndrome; (5 and 6) coarctation or interruption of the aortic arch; and (7) subaortic fibrous shelf. We carefully reviewed the operative notes from all patients with postoperative complete heart block to discover any predisposing anatomical reasons to explain the complication.

RESULTS

Two thousand seventy-nine patients had a VSD closure. Permanent complete heart block developed in 7 of 996 patients (0.7%) with an isolated defect and in 1 of 847 patients (0.1%) with tetralogy of Fallot. Four more patients had postoperative complete heart block.

CONCLUSIONS

Instances of iatrogenic complete heart block continue to occur after surgical VSD closure, either because of unexpected biological variations or because of unawareness of the disposition of the atrioventricular conduction axis in particular circumstances. This report emphasizes the latter aspect in details and suggests a risk of iatrogenic complete heart block of less than 1%.

Left ventricular mechanics after closure of ventricular septal defect: influence of size of the defect and age at surgical repair

To evaluate the influence of the size of the defect and the age of surgical repair on left ventricular mechanics, including geometry, shape, diastolic and systolic function as well as myocardial contractility, we used cross-sectional echo-Doppler to study 20 patients (12 males, 8 females) who had undergone successful surgical closure of a ventricular septal defect. The patients were divided in two groups, corrected early and late, on the basis of the degree of left-to-right shunting (ratio of pulmonary to systemic output of greater or less than 2.5/1) and the age at the surgical repair (older or younger than 2 years of age). The group undergoing early correction included 11 patients, mean age 7.1+/-1.8 years (range 4.2-11.8 years), having surgery at mean age of 1.3+/-0.6 years for a large ventricular septal defect (mean ratio of pulmonary to systemic output of 3.1/1; range 3.4-2.7/1) with a mean postoperative follow-up 4.6+/-1.9 years. The group of nine patients undergoing late correction had a mean age of 11.3+/-4.9 years (range 6.7-17.2 years), with a later surgical repair (mean age 4.7+/-2.7 years) for a moderate-sized ventricular septal defect (mean pulmonary/systemic output ratio 2.1/1; range 2.3-1.7) and a mean postoperative follow-up of 7+/-4.2 years. Each group of surgically repaired patients was compared with a control group matched for age, body surface area and gender. No significant differences were found between the normal controls and those undergoing early correction for any assessed functional index regarding left ventricular geometry (normalized volumes and mass for body surface area, mass/volume and thickness/radius ratios), shape (long axis-short axis ratio), diastolic (mitral and pulmonary venous flow patterns) and systolic (fractional shortening and rate-corrected mean velocity of circumferential fibre shortening) function. In addition, the data points for each patient for the rate-corrected mean velocity of circumferential fibre shortening to end-systolic stress relationship were within the 95% confidence limits of normal, suggesting normal left ventricular contractility. On the other hand, the patients undergoing surgery at a later age showed a persistent increase of the normalized left ventricular end-diastolic volume and mass, with an higher mass/volume ratio and reduced end-systolic stress compared with normal controls. Furthermore, left ventricular shape (long axis-short axis ratio) was abnormal at end-diastole but with its normal values at end-systole. Our data suggest that, in the presence of a large ventricular septal defect, early successful surgical repair <2 years of age results in complete recovery of left ventricular mechanics in the postoperative follow-up. In contrast, surgical closure at > 2 years of age, even for a moderately sized ventricular septal defect, deleteriously affects postoperative left ventricular geometry and shape. Since prolonged volume overload may be detrimental to myocardial function, earlier surgical repair should be recommended.

Long-term follow-up after surgical closure of ventricular septal defect in infancy and childhood

OBJECTIVES

The purpose of this study was to assess the health-related quality of life of patients who underwent surgical closure of a ventricular septal defect at a young age between 1968 and 1980.

BACKGROUND

Since the beginning of open heart surgery for congenital cardiac malformations, the surgical techniques have continually improved. As a result, even infants have become eligible for surgical repair. Long-term follow-up data are not available on the health-related quality of life of nonselected patients after surgical repair at a young age. We therefore conducted a follow-up study of 176 infants and children consecutively operated on in one institution between 1968 and 1980.

METHODS

Patients who were alive and could be traced through the offices of local registrars received an invitation to participate in the follow-up study, consisting of an interview, physical examination, echocardiography, exercise testing and standard 12-lead and 24-h electrocardiography.

RESULTS

One hundred nine patients (78% of those eligible for follow-up) participated. The mean interval after operation (+/- SD) was 14.5 +/- 2.6 years. Eighty-four percent of the patients assessed their health as good or very good, and 89% had been free of any medical or surgical intervention since the operation. At physical examination all patients were in good health. Their mean exercise capacity was 100 +/- 17% (range 56% to 141%) of predicted values; 84% of the patients had a normal exercise capacity. Echocardiography demonstrated a small residual ventricular septal defect in seven patients (6%). There were no signs of pulmonary hypertension. No patient had symptomatic arrhythmias.

CONCLUSIONS

Long-term results of surgical closure of ventricular septal defect in infancy and childhood are good. Pulmonary hypertension is absent. Personal health assessment is comparable to that of the normal population, as is exercise capacity, even though many patients have anatomic, hemodynamic or electrophysiologic sequelae.

Long-term results of primary closure for ventricular septal defects in the first year of life

The long-term results of primary closure for large ventricular septal defects (VSDs) in infants under 1 year of age with severe symptoms were studied over a period of more than 10 years. Between January, 1971 and March, 1982, 49 infants underwent primary closure of a VSD through a right ventriculotomy using complete cardiopulmonary bypass with mild hypothermia. There were four hospital deaths but no late deaths. Two of four infants with residual shunts had a left ventricular-right atrial shunt which necessitated reoperation. Surgical heart block occurred in two infants who recovered sinus rhythm in the late period. The cardiothoracic ratio decreased from 60.5% preoperatively to 50.6% in the late postoperative period. Examination by cardiac catheterization revealed that the pulmonary-to-systemic pressure ratio (Pp/Ps) of 23 patients with a Pp/Ps of over 0.75 fell from 0.89 +/- 0.09 preoperatively to 0.42 +/- 0.12 by 1 month postoperatively, then to 0.27 +/- 0.05 in the late postoperative period. The latest values for the cardiac index and left ventricular ejection fraction were 3.4 l/min per m2 and 64.4%, respectively. More than 10 years after their operation, all the survivors were growing normally and maintaining a good quality of life, which supports our recommendation that primary repair should be performed in the first year of life for infants with large VSDs.

Primary surgical closure of large ventricular septal defects in small infants

Herein, a policy of primary surgical closure of large ventricular septal defects in infants is reviewed. Forty-eight infants met criteria for inclusion in the study, and were divided into two groups based on weight: group 1 infants weighted 4 kg or less (n = 23), and group 2 infants weighed more than 4 kg (n = 25). Both groups had similar variation in ventricular septal defect location (paramembranous versus muscular) and number (single versus multiple), as well as incidence of major associated extracardiac diseases. No early deaths occurred in group 1, compared with 1 infant (4%) in group 2. Major complications occurred similarly in both groups (9% versus 12%). There were two late deaths in group 1 (9%) and none in group 2. No surviving patients have required a second ventricular septal defect operation, and the majority no longer receive anticongestive therapies. These results indicate that primary surgical closure of large ventricular septal defects, even multiple muscular defects, can be performed in very small infants with no difference in mortality or serious complication rates compared with larger infants. Protracted medical efforts to achieve larger size before primary repair and palliative pulmonary artery banding are not necessary.

Mechanism of decreased forward stroke volume in children and swine with ventricular septal defect and failure to thrive

Children with ventricular septal defect (VSD) often demonstrate failure to thrive (FTT). Such patients usually have reduced systemic cardiac output which has been postulated as a cause for their growth retardation. This study was conducted to ascertain the mechanism of the reduced cardiac output in children with VSD and FTT and also in a porcine model of VSD. Forward stroke volume was reduced in VSD-FTT children, 31 +/- 8 ml/m2, compared to normal children, 49 +/- 15 ml/m2 (P less than 0.05), but was not reduced in children with VSD and normal growth and development (41 +/- 16 ml/m2). Forward stroke volume was also reduced in swine with VSD compared to controls. Contractility assessed by mean velocity of circumferential shortening (Vcf) corrected for afterload was similar in normals and VSD-FTT children. Contractile performance was also similar in normal and VSD swine. Afterload assessed as systolic stress was similar in FTT-VSD children and normal subjects. Preload assessed as end-diastolic stress was increased in the VSD-FTT group. End-diastolic volume was not larger in the VSD-FTT group. We conclude that the reduced stroke volume seen in VSD-FTT children and VSD-swine was not due to reduced contractility, increased afterload or reduced preload. The reduced stroke volume may have been due to failure of end-diastolic volume to increase adequately.

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.

Pulmonary arterial changes in patients with ventricular septal defects and severe pulmonary hypertension

In 25 patients, aged eight months to 31 years, with ventricular septal defect (VSD; isolated in 15, the others with atrial septal defect, PDA, coarctation or patent ductus arteriosus + coarctation), each with severe pulmonary artery hypertension (pulmonary artery systolic pressure [Ppa] at least 75% of systemic and an elevated pulmonary vascular resistance), we related morphologic and morphometric data from open-lung biopsy to hemodynamic measurements obtained at cardiac catheterization during the same hospital admission. Of the hemodynamic features measured, only the ratios of pulmonary-to-systemic flow and pulmonary-to-systemic resistance correlated significantly with structure. Neither pulmonary artery pressure (Ppa) nor pulmonary vascular resistance correlated significantly with any structural feature studied. The increased external diameter of respiratory bronchiolar arteries in those with the more advanced Heath-Edwards grades reflects dilatation and suggests that it is in the small arteries of the distal arterial bed that the changes of pulmonary hypertension are most significant. Neither age nor body weight correlated significantly with the degree of structural or hemodynamic abnormality. In the ten patients who underwent VSD closure, Ppa was measured postoperatively. The Heath-Edwards grade (no more than one grade-III lesion) and arterial density (at least one-half that normal for age) were the best correlates of the difference between preoperative Ppa and Ppa immediately after corrective surgery. The presurgical catheterization data, including pulmonary resistance and the resistance ratio, did not correlate significantly with change in Ppa following VSD closure.(ABSTRACT TRUNCATED AT 250 WORDS)

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.

Primary surgical closure of ventricular septal defect in the first year of life: results in 128 infants

Between January 1973 and July 1981, 128 patients less than 1 year of age with failure to thrive, congestive heart failure or pulmonary artery hypertension underwent primary repair of a ventricular septal defect. The hospital mortality rate was 7.8% (10 of 128), and the late mortality rate was 2.3% (3 of 128). Mortality was highest among younger infants with preexisting respiratory problems or a hemodynamically significant residual lesion postoperatively. Complications included a large residual shunt in eight (6.2%), transient neurologic problems in five (3.9%) and persistent complete heart block in three (2.3%). Lung biopsy specimens obtained from 49 patients showed pulmonary vascular abnormalities in all. Complete right bundle branch block developed in 74 (64%) and bifascicular block appeared in 11 (9%). Recatheterization in 70 patients (55%) showed normal pulmonary artery pressures in all but 2 patients with a large residual shunt. Complete closure of the defect had been achieved in 49 (70%), and a hemodynamically insignificant shunt remained in 19 (27%). Patients without significant hemodynamic residua were asymptomatic and tended to accelerate in growth after surgery.

Pulmonary vascular disease in children with congenital cardiovascular malformations. Etiologic considerations

A detailed clinical analysis of 16 patients with various forms of congenital cardiac malformations with the potential for large left-to-right shunts who developed extreme pulmonary hypertension in infancy and early childhood has been carried out. The study plan was to include only patients with sufficiently long follow up to allow analysis of their course in both the prepubescent and postpubescent periods. In early life these patients were all characterized by lack of evidence for significant development of the expected left-to-right shunt indicating inappropriate maturation of their pulmonary vascular circulation. Throughout all phases of their life, they were significantly polycythemic in comparison with a control group but this polycythemia, representative of peripheral systemic hypoxemia, increased markedly with the acquisition of puberty in all patients. These two findings indicate both an early abnormality, suggestively primary, of the pulmonary vasculature and a late progression of the disease associated with pubertal maturation.

Results of surgical treatment of ventricular septal defects with pulmonary hypertension

Two hundred and twenty-five consecutive patients with interventricular septal defect and associated pulmonary hypertension have undergone corrective surgery at the Christian Medical College Hospital. The mean preoperative systolic pulmonary artery pressure was 70.5 (range 31-136) mm Hg and the calculated pulmonary vascular resistance ranged from 300 to 1680 dyn/s cm-5. A paracoronary right ventriculotomy was the approach of choice. Profound hypothermia and circulatory arrest were not used, even in 12 patients weighing under 10 kg. Among the older children and young adolescents there were 27 who had a calculated pulmonary vascular resistance of over 800 dyn/s cm-1 and their mortality was 22%, which is good when compared with that of other series. It is evident that both the early and the late death rate after surgery increase with the age of the patient, especially in those with associated pulmonary hypertension. In 69 patients studied after repair recatheterisation showed no residual defect by oximetry. The fall in the pulmonary artery pressures after surgery has been striking in most patients. The late death rate was 2.5%. The surviving patients are leading normal, active lives.

Rest and exercise ventricular function in adults with congenital ventricular septal defects

Rest and exercise right and left ventricular function were compared using equilibrium gated radionuclide angiography in 19 normal sedentary control subjects (mean age 28 years, range 22 to 34) and 34 patients with hemodynamically documented congenital ventricular septal defect (VSD) (mean age 27 years, range 20 to 40). The 34 patients with VSD were divided into 3 groups: those in Group 1 (17 patients) had pulmonary to systemic blood flow ratios of less than 2 to 1; those in Group 2 (12 patients) had prior surgical closure of VSD (mean interval from surgery 17 years, range 9 to 22), and those in Group 3 (5 patients) had Eisenmenger's complex. Gated radionuclide angiography was performed at rest and during each level of graded supine bicycle exercise to fatigue. Heart rate, blood pressure, maximal work load achieved, and right and left ventricular ejection fractions were assessed. The control subjects demonstrated an increase in both the left and right ventricular ejection fractions with exercise (0.70 +/- 0.07 to 0.79 +/- 0.05 and 0.46 +/- 0.06 to 0.57 +/- 0.04; p less than 0.001 for left and right ventricles, respectively). All study groups failed to demonstrate an increase in ejection fraction in either ventricle with exercise. Furthermore, resting left ventricular ejection fraction in Groups 2 and 3 was lower than that in the control subjects (0.59 +/- 0.09 and 0.54 +/- 0.06 versus 0.70 +/- 0.07; p less than 0.001) and resting right ventricular ejection fraction was lower in Group 3 versus control subjects (0.30 +/- 0.07 versus 0.46 +/- 0.06; p less than 0.001). Thus (1) left and right ventricular function on exercise were abnormal in patients with residual VSD as compared with control subjects; (2) rest and exercise left ventricular ejection fractions remained abnormal despite surgical closure of VSD in the remote past; (3) resting left and right ventricular function was abnormal in patients with Eisenmenger's complex; (4) lifelong volume overload may be detrimental to myocardial function.

Transatrial repair of double-outlet right ventricle in infants

In three infant cases of double outlet right ventricle (DORV), two with normally related great arteries (NGA) and one with side-by-side great arteries, a transatrial repair was carried out. In all three cases, the results were excellent. It is concluded that in the small baby with DORV with NGA and in DORV with side-by-side great arteries with a hypoplastic crista, a transatrial repair should be successful. This is dependent on the VSD being in the perimembranous (and, therefore, subaortic) location and on the absence of infundibular pulmonary stenosis. In all other varieties of DORV the repair should probably be done through the ventricle.

Conduction defects, ventricular arrhythmias, and late death after surgical closure of ventricular septal defect

One hundred and eighty-seven patients who had surgical closure of a ventricular septal defect between 1958 and 1975 were followed for up to 21 years. there were 17 late sudden deaths of which eight occurred in completely fit patients while nine were already under medical care. In an attempt to elucidate possible risk factors and reoperative and serial postoperative electrocardiograms of all patients were studied. Fifty-one unselected healthy follow-up patients agreed to 24 hour ambulatory monitoring. Progressive exercise testing (Bruce protocol) was carried out on 31 of them and an additional seven patients. There was a significant correlation between recorded ventricular arrhythmias and conduction defects, particularly progressive conduction defects. Transient complete heart block carried a bad prognosis and grade 3-4b ventricular arrhythmias were a major risk factor and recorded in 10 of the 17 patients who died. Long-term postoperative electrocardiographic follow-up is recommended and 24 hour ambulatory monitoring and exercise testing complement the findings of the resting electrocardiogram. The long-term treatment of survivors found to have ventricular arrhythmias must be considered.

Radionuclide angiocardiographic assessment of pulmonary vascular reactivity in patients with left to right shunt and pulmonary hypertension

Radionuclide angiocardiography was used to assess pulmonary vascular reactivity in eight patients (nine studies) with a large, relatively unrestrictive intracardiac defect and pulmonary arterial hypertension. Radionuclide angiocardiograms, using technetium-99m pertechnetate, were performed first with the patient breathing room air and then after 10 minutes of breathing a mixture containing 90 percent or more of oxygen. The pulmonary to systemic flow ratios obtained by gamma variate analysis of the radionuclide time-activity curves were compared with those calculated with the Fick principle at the time of cardiac catheterization. There was a good correlation between the two methods both in room air studies (r = 0.88) and in those obtained with 90 percent or more of oxygen (r = 0.94). All six studies (in five patients) with a reactive pulmonary vasculature (judged by a pulmonary vascular resistance at cardiac catheterization of less than 6 units/m2 with oxygen or after tolazoline) had a radionuclide pulmonary to systemic flow ratio of 3.0 or greater with oxygen. The three patients with a nonreactive pulmonary vasculature had a radionuclide pulmonary to systemic flow ratio of 2.3 or less with oxygen, a value that was unchanged from the room air value. These data suggest that radionuclide angiocardiography may be a useful, relatively noninvasive method of assessing pulmonary vascular reactivity in patients with a large, relatively unrestrictive intracardiac defect.

The pulmonary vascular response to oxygen and its influence on operative results in children with ventricular septal defect

The ratio of pulmonary vascular resistance to systemic resistance was determined before and after oxygen administration in 25 children with an isolated large ventricular septal defect and elevated pulmonary vascular resistance (pulmonary/systemic resistance ratio, Rp/Rs greater than 0.25). A fall of 30% or more in the Rp/Rs, after 20 minutes of oxygen inhalation (FiO2 greater than 0.90), was considered a positive response to oxygen. In the 6 children with Down's syndrome, the Rp/Rs fell significantly more in oxygen (52%) than it did in the 19 children without Down's syndrome (31%, p less than 0.05). No other clinical or baseline hemodynamic finding was predictive of vascular responsiveness. Seventeen children underwent closure of the ventricular septal defect. Three of 11 children who responded to O2 expired shortly after operation; each of the 6 children who did not respond to O2 survived operation. Two of the deaths (occurring less than 12 hours after closure) were from low cardiac output; a third child died suddenly 5 days postoperatively. Thirteen children, 7 who responded to oxygen and 6 who did not, were restudied by cardiac catheterization an average of 2.0 years following successful closure of the ventricular septal defect. While the Rp/Rs in room air fell following closure of the defect in both groups, the decrease was 22% in responders and 28% in nonresponders. The results of this study, unlike similar studies performed at higher altitudes, suggest that the preoperative responsiveness of the pulmonary vasculature to oxygen does not predict either operative survival or postoperative pulmonary vascular resistance.

Diagnosis and management of postoperative pulmonary hypertensive crisis

In this paper we discuss two infants and one child who experienced a previously unreported complication after complete correction of a large, unrestrictive ventricular septal defect. Two patients had documented pulmonary hypertensive crises and severe right-heart failure secondary to hypoxia and pulmonary vasoconstriction. These crises were associated with significantly increased right ventricular (RV) peak systolic and end-diastolic pressures and right-to-left shunting via a foramen ovale which, in turn, exaggerated the hypoxis. The crises were treated successfully with tolazoline in the second and third patients. RV pressure returned to normal values and have remained normal up to 12 months postoperatively in the second patient. Although the RV pressures decreased with tolazoline in the third patient, they never reached normal values. Postoperative monitoring of pulmonary artery and RV pressures in infants with large ventricular septal defects is essential when unexplained complications are encountered. Tolazoline proved to be very effective in the treatment of two patients with pulmonary vasoconstriction secondary to hypoxia.

Conduction disturbances after surgical correction of ventricular septal defect by the atrial approach

Conduction disturbances have been documented after correction of ventricular septal defects by the ventricular route. Recently, repair of the ventricular septal defect has been through the right atrium to overcome damage to the conduction system and a right ventriculotomy. Thirty-nine children with ventricular septal defects under the age of 5 years were operated upon by the atrial route (group 1). The incidence of conduction disturbances in this group was compared with that occurring in 19 children of comparable age with a ventricular septal defect repaired via a right ventriculotomy (group 2). Complete right bundle-branch block developed in 13 of 39 children (33.3%) in group 1, compared with 15 of 19 children (78.9%) in group 2. This was a statistically significant reduction in complete right bundle-branch block in group 1. The incidence of left axis deviation occurring with complete right bundle-branch block was similarly statistically reduced. Transient complete heart block and arrhythmias were not statistically different in the two groups. The atrial approach to the repair of the ventricular septal defect significantly reduced the incidence of complete right bundle-branch block alone and occurring with left axis deviation.

Lung biopsy in congenital heart disease: a morphometric approach to pulmonary vascular disease

Fifty patients with congenital heart disease, ages 2 days-30 years (median 12 months) at cardiac surgery, underwent lung biopsy to assess pulmonary vascular disease (PVD). Twenty-six had ventricular septal defects (VSD), 17 d-transposition of the great arteries (D-TGA), and seven, defects of the atrioventricular canal (AVC). Quantitative morphologic data was correlated with hemodynamic data. Three new grades of PVD were observed. Abnormal extension of muscle into peripheral arteries (grade A) was found in all patients; all had increased pulmonary blood flow. In addition, 38 of 50 patients had an increase in percentage arterial wall thickness (grade B); this correlated with elevation in pulmonary artery (PA) pressure (r = 0.59). Another 10 of 50 patients had, in addition to A and B, a reduction in the number of small arteries (grade C); nine of 10 were patients with elevated PA resistance greater than 3.5 mu/m2 (P less than 0.005). All three patients with Heath-Edwards changes of grade III or worse also had grade C. Reduction in peripheral arterial number probably precedes obliterative PVD and may identify those patients in whom, despite corrective surgery, PVD will progress.