Postoperative assessment of patients with ventricular septal defect and pulmonary hypertension. Response to intense upright exercise

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.

Pulmonary hypertension's variegated landscape: a snapshot

The many types of pulmonary hypertension (PH) are so protean in their biological origin, histological expression, and natural history that it is difficult to create a summary picture of the disease, or to easily compare and contrast characteristics of one type of PH with another. For newcomers to the field, however, such a picture would facilitate a broad understanding of PH. In this paper, we suggest that four characteristics are fundamental to describing the nature of various types of PH, and that taken together they define a number of patterns of PH expression. These characteristics are histopathology, developmental origin, associated clinical conditions, and potential for resolution. The “snapshot” is a way to concisely display the ways that these signal characteristics intersect in select specific types of PH, and is an effort to summarize these patterns in a way that facilitates a “big picture” comprehension of this disease.

Pulmonary Hypertension in Congenital Heart Disease: Beyond Eisenmenger Syndrome

Patients with adult congenital heart disease have an increased risk of developing pulmonary hypertension. There are several mechanisms of pulmonary hypertension in patients with adult congenital heart disease, and understanding them requires a systematic approach to define the patient's hemodynamics and physiology. This article reviews the updated classification of pulmonary hypertension in patients with adult congenital heart disease with a focus on pathophysiology, diagnostics, and the evaluation of pulmonary hypertension in special adult congenital heart disease populations.

Anesthetic management of the adult patient with congenital heart disease

As the number of CHD repairs in adults continues to increase, these operations will be performed in a wider variety of institutions and systems. Unfortunately, not all of these centers will have an optimal environment for correcting CHD in adults. This type of surgery is best accomplished in a facility specifically designed for treating adults with CHD. Optimal care of these patients is provided by cardiologists who are trained and experienced in pediatric and adult cardiology, by surgeons who are trained and experienced in treating CHD, and by anesthesiologists who are experienced in caring for adults with CHD. Whatever the setting, cardiac anesthesiologists involved in these cases must be thoroughly aware of the anesthetic implications for the unique pathophysiology of each patient, and they must not rely on their "usual" expectations of either true pediatric CHD or acquired adult heart disease.

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.

The adult patient with congenital heart disease

In adults with congenital heart disease who are confronted with noncardiac surgery, perioperative risks can be reduced, often appreciably, when problems inherent to this patient population are anticipated. The first necessity is to clarify the diagnosis and to be certain that appropriate information is obtained from a cardiologist with adequate knowledge of congenital heart disease in adults. Physiology and anatomy can vary significantly among patients who superficially carry identical diagnoses. Elective noncardiac surgery should be preceded by clinical assessment including review of clinical and laboratory data and securing the results of necessary diagnostic studies. Preoperative assessment should be performed far enough in advance of the anticipated date of surgery to allow critical assessment of the data and potential discussions with colleagues. Appropriate cardiovascular laboratory studies to be obtained or reviewed include electrocardiograms, chest radiographs, echocardiograms, and cardiac catheterization data, which may include specialized intracardiac electrophysiologic testing. Congenital heart disease in adults is a new and evolving area of special interest and expertise in cardiovascular medicine. Multidisciplinary centers for the care of these patients are being developed. The 22nd Bethesda Conference recommended that these centers include among their consultants anesthesiologists with special expertise in managing patients with congenital heart disease. These anesthesiologists can have the option of serving either as the attending anesthesiologists when patients require noncardiac surgery or as consultants and resource individuals to other anesthesiologists.

Pulmonary vascular resistance during exercise late after repair of large ventricular septal defects. Relation to age at the time of repair

Postoperative pulmonary artery pressure and resistance were assessed during exercise in 32 patients late after repair of large ventricular septal defect with pulmonary hypertension. Nineteen patients had a preoperative pulmonary-to-systemic resistance ratio of between 0.15 and 0.50 (group 1) and 13 had a ratio between 0.50 and 0.96 (group 2). Age at the time of operation was 0.9 to 13.0 years (4.6 +/- 3.6) in group 1 and 0.8 to 15.8 years (4.3 +/- 4.2) in group 2. Age at the time of restudy was 9 to 21 years (14.5 +/- 3.0) in group 1 and 9 to 22 years (13.5 +/- 4.1) in group 2. Pulmonary artery pressure was measured in the supine position at rest and during exercise, as were the measurements underlying the calculations of pulmonary vascular resistance. Mean pulmonary artery pressure was 13 to 21 mm Hg (17 +/- 2) and 10 to 26 mm Hg (20 +/- 5) in groups 1 and 2, respectively, at rest, and this increased to 17 to 27 mm Hg (22 +/- 3) and 14 to 39 mm Hg (27 +/- 7) in groups 1 and 2, respectively, during exercise (p < 0.05). Pulmonary vascular resistance was 0.51 to 3.40 U.m2 (1.93 +/- 0.63) and 0.79 to 3.31 U.m2 (2.05 +/- 0.65) in groups 1 and 2 at rest. It was 0.58 to 2.24 U.m2 (1.36 +/- 0.57) and 0.81 to 3.85 U.m2 (2.18 +/- 0.97) in groups 1 and 2 during exercise (p < 0.01). Postoperative pulmonary vascular resistance during exercise correlated well with age at the time of repair in both groups (r = 0.65, p < 0.05 in group 1; r = 0.86, p < 0.001 in group 2). These data suggest that 85% of patients with a preoperative pulmonary-to-systemic resistance ratio of between 0.15 and 0.50 would have normal pulmonary vascular resistance during exercise when operated on at younger than 3.8 years old and 85% of those with a preoperative pulmonary-to-systemic resistance ratio of more than 0.50 would have normal pulmonary vascular resistance during exercise when operated on at younger than 1.1 years.

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.

Cardiorespiratory exercise capacity after surgical closure of atrial septal defect is influenced by the age at surgery

To study the influence of age at the time of the operation on long-term functional performance in children undergoing surgery for atrial septal defect (ASD) of the secundum type, exercise tolerance was assessed in 24 patients and values were compared with those of normal subjects. Patients were divided into two groups: 11 patients had surgery before the age of 5 years (group 1) and 13 patients had surgery at a later age (group 2). There were no significant differences between groups 1 and 2 with regard to the pulmonary-to-systemic flow ratio, pulmonary artery pressure, and the interval between surgery and exercise testing. Performance capacity was assessed by determination of the ventilatory threshold during submaximal exercise. The mean value for the ventilatory threshold in group 1 was normal (99.4 +/- 15.1% of the age-predicted normal value). In the children who were more than 5 years of age at the time of the operation, the ventilatory threshold was below normal (84.5 +/- 10.9% of the age-predicted normal value). Furthermore, in group 2 more patients (77%) had values that were below normal (below the 95% confidence limit of the age-predicted normal value) compared with group 1 (27%). It is concluded that functional performance capacity is better when surgical closure of ASD is performed in early childhood and before the age of 5 years rather than at a later age.

Comparison of cardiovascular adjustments to exercise in adolescents 8 to 15 years of age after correction of tetralogy of fallot, ventricular septal defect or atrial septal defect

Surgical correction of tetralogy of Fallot (TF) has generally been associated with a reduced maximal exercise tolerance, possibly related to the ventriculotomy inherent to the intracardiac repair procedure. This study documents the exercise hemodynamics of a group of patients operated on for TF who showed similar clinical and functional characteristics, and compares these responses to those of age-matched patients operated on for an isolated ventricular septal defect (VSD) or atrial septal defect (ASD) in an attempt to better understand the role of the ventriculotomy in the exercise limitation. Thirty patients, ages 12 to 19 years, operated on before 5 years of age for complete repair of TF (n = 13), VSD (n = 7) or ASD (n = 10) and 10 age-matched control subjects underwent a progressive maximal cycling test to determine the maximal oxygen uptake (VO2 max), and completed submaximal cycling at intensities of 33 and 66% VO2 max, respectively, to determine the cardiac output (CO2-rebreathing). No significant differences in VO2 max were observed (TF = 37.6 +/- 10; VDS = 34.0 +/- 9.2; ASD = 36.5 +/- 7; controls = 41.3 +/- 6.0 ml/kg/min). The maximal heart rate, however, remained lower in all patient groups in comparison with control subjects (p less than or equal to 0.05) (TF = 178 +/- 14; VSD = 172 +/- 17; ASD = 179 +/- 16; controls = 191 +/- 12 beats/min).(ABSTRACT TRUNCATED AT 250 WORDS)

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.

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.

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)

Vascular structure in lung tissue obtained at biopsy correlated with pulmonary hemodynamic findings after repair of congenital heart defects

At the time of surgical repair, a lung biopsy was performed on patients with congenital heart defects who either had pulmonary hypertension or in whom it would be likely to develop if the lesion were not corrected. Pulmonary vascular changes, assessed morphometrically and also according to the classification of Heath and Edwards (Circulation 18: 533, 1958), were correlated with the postoperative pulmonary hemodynamic findings: mean pulmonary arterial pressure the day after correction and mean pulmonary arterial pressure and pulmonary vascular resistance measured 1 year later. On the first postoperative day, increased mean pulmonary arterial pressure was uncommon in patients with morphometric grade A or B (mild) biopsy findings and Heath-Edwards grade N (normal), and if it was present it was of a mild degree. Mean pulmonary arterial pressure was commonly elevated in those with grade B (severe) or C (mild or severe) and Heath-Edwards grade I biopsy results and was more frequently elevated in those with grade II findings. Moderate-to-severe elevation of mean pulmonary arterial pressure was invariable in patients with Heath-Edwards grade III changes regardless of the morphometric grade. One year after repair, mean pulmonary arterial pressure and/or pulmonary vascular resistance were normal in all patients whose conditions were corrected surgically before 9 months of age regardless of the severity of the pulmonary vascular changes. Values were normal in patients whose conditions were repaired surgically at 9 months of age or later who had grade A or B (mild) morphometric findings with any Heath-Edwards grade or grade B (severe) morphometric findings with Heath-Edwards grade I but were increased in half of the patients with grade B (severe) morphometric findings and Heath-Edwards grade II or with grade C (mild or severe) and Heath-Edwards grade I or II changes. Pulmonary arterial pressure and pulmonary vascular resistance were increased in all patients whose conditions were repaired after 2 years of age with grade C morphometric findings and to a severe degree if associated with Heath-Edwards grade III. Thus, although the Heath-Edwards grade can usually be used to identify patients at risk for pulmonary hypertension in the early postoperative period, both the morphometric and the Heath-Edwards grades as well as the age of the patient at the time of repair can be used to determine whether pulmonary arterial pressure and resistance eventually return to normal or remain elevated.

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.

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.

Ventricular performance in adults after operation for congenital heart disease

Symptomatic ventricular dysfunction in adults who have had reparative operations for the more common congenital heart defects is uncommon. However, both invasive and noninvasive laboratory assessments of ventricular function have revealed abnormalities in some subsets of patients after repair of atrial septal defect, ventricular septal defect, aortic or pulmonary stenosis, tetralogy of Fallot, transposition of the great arteries and tricuspid atresia. Possible causative factors of late ventricular dysfunction after repair include the duration and severity of volume or pressure overload; the duration and severity of cyanosis; intermittent episodes of imbalance between myocardial oxygen supply and demand; residuae, sequelae and complications of treatment; and acquired disease. Further long-term follow-up studies are needed to assess the effect of current methods of therapy as well as timing of operative intervention on ventricular function in adults.

Clinical problems of postoperative pulmonary vascular disease

The younger the patient with a large left to right shunt at the time of operation, the greater the likelihood that pulmonary vascular resistance will fall to normal thereafter. In older patients, the degree to which the pulmonary vascular resistance is elevated before operation is a critical factor determining operability and prognosis. Patients at particularly high risk for the development of significant pulmonary vascular obstruction early in life are those with certain forms of cyanotic congenital heart disease, such as complete transposition of the great arteries with ventricular septal defect and patent ductus arteriosus, and truncus arteriosus. Other conditions in which pulmonary vascular obstruction appears to progress rapidly include large ventricular septal defect, complete atrioventricular canal defect and left to right shunt lesions in an environment of high altitude or associated with unilateral pulmonary arterial absence of the Down's syndrome. In this report the framework is reviewed for recognizing that important pre- and postnatal modifiers of the pulmonary vascular bed may be lesion-dependent. Thus, the growth and development of the pulmonary vascular bed during fetal and early postnatal life, as well as the morphologic alterations described in detail by Heath and Edwards, are likely to determine the ultimate intensity and magnitude of pulmonary vascular obstruction. Commentary is also provided concerning the management of patients with high pulmonary vascular resistance during pregnancy and delivery, their response to exercise, and the possibility of medical treatment designed to reduce pulmonary vascular resistance, and perhaps prolong life and enhance its quality.

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.

Assessment of left-to-right shunt and left ventricular function in isolated ventricular septal defect. Echocardiographic study

This echocardiographic study was designed to assess left ventricular function and pulmonary blood flow in ventricular septal defect. Fifty-one patients aged 2 weeks to 21 years were investigated (group 2). Five of 10 operated patients were studied one week after surgical closure of the defect (group 3) and seven 3 to 6 weeks postoperatively (group 4). The control group consisted of 45 normal subjects aged 2 weeks to 21 (group 1). Left atrium/aortic root dimension ratio (LA/Ao) was used to express the pulmonary systemic flow ratio. Left ventricular chamber size was assessed by measurement of left ventricular end-diastolic dimension and volume. The left ventricular mass and the ratio of end-diastolic volume to left ventricular mass were determined to relate the degree of left ventricular hypertrophy to volume overload. Myocardial function was evaluated using ejection phase indices. Ventricular septal thickness, posterior wall thickness, and echocardiographic patterns of septal motion were also studied. The left atrium/aortic root dimension, end-diastolic volume, and left ventricular mass were significantly greater in group 2 patients (P less than 0.05) than in the normal controls. There was a very good correlation between LA/Ao and pulmonary/systemic flow ratio (r = 0.83). Eleven of the group 2 patients showed asymmetric septal hypertrophy (unrelated to shunt size) but left ventricular function as assessed by ejection phase indices appeared unimpaired. Immediately after operation (group 3) there was a deterioration in left ventricular function in 5 patients as shown by reduced ejection fraction, mean velocity of circumferential shortening, and relative changes in minor axis with systole. Septal motion was impaired but returned to normal in 3 to 6 weeks in 7 patients (group 4). Left atrial/aortic root dimension, end-diastolic volume, and left ventricular mass decreased significantly immediately after operation (group 3) but were still raised at 3 to 6 weeks (group 4).

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.

Functional status of patients with large ventricular septal defect and pulmonary vascular disease 6 to 16 years after surgical closure of their defect in childhood

We have reviewed 27 patients now 6 to 16 years after closure of a ventricular septal defect at 3 to 12 years of age associated with pulmonary hypertension with a view to assessing their quality of life, respiratory function, and exercise performance. All the patients led normal unrestricted lives. Their subjective lack of symptoms was, in general, confirmed by the results obtained from assessment of lung function tests and two-stage exercise testing in 19 volunteers. Abnormal ventilation in relation to work load was noted in 5 patients and a slightly low exercise cardiac output in 6. Although the patients led normal lives and had a satisfactory response to exercise, measurement of pulmonary artery pressure showed striking pulmonary hypertension on effort. Despite the satisfactory progress of these patients their more long-term future must be one of conjecture and their residual pulmonary hypertension, indicative of residual pulmonary obstruction, must lend weight to arguments for earlier closure of ventricular septal defect before 1 to 2 years of age when changes in the pulmonary vascular bed may be reversed after closure of the defect.

Hypertensive pulmonary vascular disease in children. Detection by radioactive nitrogen (13N) inhalation and injection

Regional lung function has been studied in 16 children with intracardiac shunts and a variety of associated cardiac anomalies using radioactive nitrogen (13N) and a gamma camera-computer system. The distribution and washout of inhaled 13N were usually normal. The distribution of intravenously injected 13N was often abnormal and could be related to local anatomy. The most important finding was delayed clearance by ventilation of intravenously injected 13N in children with an abnormally raised pulmonary/systemic vascular resistance ratio (Rp/Rs) at cardiac catheterisation. The regional localisation of this ventilation-perfusion imbalance could be related in several children to the probable distribution of hypertensive pulmonary vascular disease, predicted either from local anatomy shown at cardiac catheterisation or from the abnormal distribution of pulmonary perfusion. Abnormalities present on breathing air may be partially reversed on breathing 100 per cent oxygen.

Ventricular septal defect: results after repair in infancy

During the 19 years from 1957 through 1975, there have been 106 patients under age 2 years who have undergone surgery for repair of a large ventricular septal defect at the University of Michigan Medical Center. The majority of the patients had either severe pulmonary hypertension or intractable congestive heart failure. Eighty-three infants survived operation; there has been one late death. The greatest mortality occurred in patients under age 6 months and in those with severe pulmonary hypertension. Surviving infants showed marked symptomatic improvement and change in growth patterns. Complications included the development of complete right bundle branch blodk or left anterior hemiblock in approximately 50 percent of patients and, in one instance, complete atrioventricular block. Forty-five patients have undergone cardiac catheterization 1 to 8 years postoperatively. Although 17 were found to have residual septal defects only 3 of these had a pulmonary to systemic flow ratio of 1.5:1 or more, and reoperation was accomplished without incident in these 3 patients and in 3 others with smaller shunts. With one exception, postoperative pulmonary arterial pressures and pulmonary to systemic vascular resistance ratios were normal or near normal, thus representing a significant contrast with findings in patients operated on after age 2 years. Whereas the complications of surgery appear no greater in the infant than in the older patient, many of the benefits can be realized only with operation at the earlier age.

Surgical treatment of large ventricular septal defect with pulmonary hypertension in the first 24 months of life

A total of 74 patients under 24 months of age with large ventricular septal defects (VSD) and pulmonary hypertension were subjected to surgical treatment from 1969 through 1975. Emergency pulmonary artery (PA) banding was performed in 13 patients during the first year of life with 1 death from postoperative respiratory failure. Primary closure of the VSD was performed in 61 patients using simple hypothermia and short-term coronary perfusion, with an operative mortality of 1.6%. There were no late deaths or neurological disturbances. Normal hemodynamic data were obtained in all 7 patients who underwent postoperative cardiac catheterization from one month to five years after the primary correction. It is concluded that primary closure of a VSD in infancy is reasonable and that PA banding is indicated only for those patients less than 6 months old with a complicated defect or in an emergency situation.

Left heart volume characteristics following ventricular septal defect closure in infancy

Left ventricular and left atrial volume, left ventricular ejection fraction, and left ventricular muscle mass were determined preoperatively and postoperatively in 13 patients who underwent surgical closure of ventricular septal defects in the first two years of life. Left ventricular end-diastolic volume and systolic output averaged 255 +/- 19% (+/- SEM) and 240 +/- 19% of normal, respectively, before operation but fell to within normal limits postoperatively. Left ventricular ejection fraction was normal preoperatively (100 +/- 4% of normal) and remained so after correction (106 +/- 3%, NS). Left ventricular mass was mildly elevated at the preoperative catheterization (271 +/- 21%) and decreased significantly following repair (P less than 0.001). However, the postoperative left atrial volume (147 +/- 14%) remained abnormal (P greater than 0.05). These data suggest that when early surgical closure of a ventricular septal defect is necessary because of failure of medical management, good results with regard to postoperative left ventricular size and function can be expected.