Surgical closure of a ventricular septal defect in early childhood leads to altered pulmonary function in adulthood: A long-term follow-up

Cardiopulmonary functional capacity in Taiwanese children with ventricular septal defects

BACKGROUND

Children with ventricular septal defects (VSDs) are considered to have no difference in cardiopulmonary functional capacity with healthy children of the same age; however, studies have shown contradictory findings. The aim of this study was to assess whether Taiwanese children with VSDs exhibited cardiopulmonary deficits.

METHODS

This is a retrospective cohort study with the data collected from January 2010 to December 2021. All patients and controls (age-, sex-, and body mass index -matched) underwent cardiopulmonary exercise testing (CPET) and pulmonary function test.

RESULTS

In total, 157 VSD patients (80 patients with surgically closed VSDs, 77 patients with unrepaired VSDs) and 157 healthy controls were recruited. Pulmonary function test showed significant among-group differences in maximal voluntary ventilation (MVV) (p = 0.015). The surgically closed group had lower MVV compared to the control group. Regarding CPET, we found VSD patients had lower peak oxygen uptake than the controls (surgically closed group: 30.84 ± 6.27 ml/kg/min; unrepaired group: 32.00 ± 5.95 ml/kg/min; control group: 36.76 ± 6.50 ml/kg/min, p < 0.001). There was also significant among-group differences in aerobic capacity (surgically closed group: 21.20 ± 4.39 ml/kg/min; unrepaired group: 21.68 ± 4.47 ml/kg/min; control group: 26.25 ± 4.33 ml/kg/min, p < 0.001). In addition, the surgically closed group had lower heart rate average at anaerobic threshold than the control group (surgically closed group: 138.11 ± 16.42 bpm; control group: 145.78 ± 15.53 bpm, p = 0.002).

CONCLUSION

Taiwanese children with VSD, whether surgically closed or not, have poorer cardiopulmonary performance than age-matched healthy children, and the results of the surgically closed group were even worse.

Respiratory mechanics and gas exchange in an ovine model of congenital heart disease with increased pulmonary blood flow and pressure

In a model of congenital heart disease (CHD), we evaluated if chronically increased pulmonary blood flow and pressure were associated with altered respiratory mechanics and gas exchange. Respiratory mechanics and gas exchange were evaluated in 6 shunt, 7 SHAM, and 7 control age-matched lambs. Lambs were anesthetized and mechanically ventilated for 15 min with tidal volume of 10 mL/kg, positive end-expiratory pressure of 5 cmH2O, and inspired oxygen fraction of 0.21. Respiratory system, lung and chest wall compliances (Crs, CL and Ccw, respectively) and resistances (Rrs, RL and Rcw, respectively), and the profile of the elastic pressure-volume curve (%E2) were evaluated. Arterial blood gases and volumetric capnography variables were collected. Comparisons between groups were performed by one-way ANOVA followed by Tukey-Kramer test for normally distributed data and with Kruskal-Wallis test followed by Steel-Dwass test for non-normally distributed data. Average Crs and CL in shunt lambs were 30% and 58% lower than in control, and 56% and 68% lower than in SHAM lambs, respectively. Ccw was 52% and 47% higher and Rcw was 53% and 40% lower in shunt lambs compared to controls and SHAMs, respectively. No difference in %E2 was identified between groups. No difference in respiratory mechanics was observed between control and SHAM lambs. In shunt lambs, Rcw, Crs and CL were decreased and Ccw was increased when compared to control and SHAM lambs. Pulmonary gas exchange did not seem to be impaired in shunt lambs when compared to controls and SHAMs.

Congenital heart disease-associated pulmonary dysplasia and its underlying mechanisms

Clinical observation indicates that exercise capacity, an important determinant of survival in patients with congenital heart disease (CHD), is most decreased in children with reduced pulmonary blood flow (RPF). However, the underlying mechanism remains unclear. Here, we obtained human RPF lung samples from children with tetralogy of Fallot as well as piglet and rat RPF lung samples from animals with pulmonary artery banding surgery. We observed impaired alveolarization and vascularization, the main characteristics of pulmonary dysplasia, in the lungs of RPF infants, piglets, and rats. RPF caused smaller lungs, cyanosis, and body weight loss in neonatal rats and reduced the number of alveolar type 2 cells. RNA sequencing demonstrated that RPF induced the downregulation of metabolism and migration, a key biological process of late alveolar development, and the upregulation of immune response, which was confirmed by flow cytometry and cytokine detection. In addition, the immunosuppressant cyclosporine A rescued pulmonary dysplasia and increased the expression of the Wnt signaling pathway, which is the driver of postnatal lung development. We concluded that RPF results in pulmonary dysplasia, which may account for the reduced exercise capacity of patients with CHD with RPF. The underlying mechanism is associated with immune response activation, and immunosuppressants have a therapeutic effect in CHD-associated pulmonary dysplasia.

Functional Capacity Past Age 40 in Patients With Congenital Ventricular Septal Defects

Background

Ventricular septal defects (VSD), when treated correctly in childhood, are considered to have great prognoses, and the majority of patients are discharged from follow‐up when entering their teens. Young adults were previously found to have poorer functional capacity than healthy peers, but the question remains whether functional capacity degenerates further with age.

Methods and Results

A group of 30 patients with surgically closed VSDs (51±8 years) with 30 matched, healthy control participants (52±9 years) and a group of 30 patients with small unrepaired VSDs (55±12 years) and 30 matched control participants (55±10 years) underwent cardiopulmonary exercise testing using an incremental workload protocol and noninvasive gas measurement. Peak oxygen uptake was lower in participants with closed VSDs than matched controls (24±7 versus 34±9 mL/min per kg, P<0.01) and with unrepaired VSDs than matched controls (26±5 versus 32±8 mL/min per kg, P<0.01). Patients demonstrated lower oxygen uptake from exercise levels at 20% of maximal workload compared with respective control groups (P<0.01). Peak ventilation was lower in patients with surgically closed VSDs than control participants (1.0±0.3 versus 1.4±0.4 L/min per kg, P<0.01) but similar in patients with unrepaired VSDs and control participants (P=0.14). Exercise capacity was 29% lower in older patients with surgically closed VSDs than healthy peers, whereas younger patients with surgically closed VSDs previously demonstrated 18% lower capacity compared with peers. Older patients with unrepaired VSDs reached 21% lower exercise capacity, whereas younger patients with unrepaired VSDs previously demonstrated 17% lower oxygen uptake than healthy peers.

Conclusions

Patients with VSDs demonstrate poorer exercise capacity than healthy peers. The difference between patients and control participants increased with advancing age—and increased most in patients with operated VSDs—compared with previous findings in younger patients. Results warrant continuous follow‐up for these simple defects.

Comparison of Outcomes in Adults With Ventricular Septal Defect Closed Earlier in Life Versus Those in Whom the Defect Was Never Closed

Ventricular septal defects (VSDs) have recently demonstrated poorer functional outcome with disrupted ventricular contractility during exercise in young patients. It is not known whether this will change with age. Therefore, echocardiography was performed in older patients with congenital VSDs, either surgically closed or unrepaired and all without Eisenmenger physiology, to compare functional outcomes with healthy peers. Transthoracic echocardiography was performed at rest and during supine bicycle exercise, with tissue velocity Doppler for assessment of primary end points: isovolumetric acceleration and systolic velocities. In total, 30 surgically closed VSDs (51 ± 8 years) with 30 healthy controls (52 ± 9 years) and 30 unrepaired VSDs (55 ± 12 years) with 30 matched controls (55 ± 10 years) were included. Surgical patients displayed lower right ventricular (RV) systolic and early diastolic-filling velocities compared with controls, p <0.01, lower tricuspid annular plane systolic excursion (17.8 ± 5 vs 22.7 ± 3mm, p <0.01) and lower fractional area change (37.8 ± 6 vs 46.4% ± 7%, p <0.01). Unrepaired VSDs also had lower RV fractional area change than matched controls (39.9 ± 7 vs 48.4% ± 7%, p <0.01). Both patient groups had more tricuspid regurgitation and larger RV outflow tract dimensions than controls, p <0.01. During exercise, isovolumetric acceleration and systolic velocities were lower in both patient groups compared with controls, with the difference increasing with workload level. In conclusion, adults in their mid-50s with surgically closed or unrepaired VSDs have abnormal RV function at rest, with even more pronounced differences during exercise. These results suggest that a VSD, whether repaired early or considered hemodynamically insignificant, is not a benign lesion and continuous follow-up of adults is warranted.

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 Function in Older Patients With Ventricular Septal Defect

To better understand the evolvement of the pulmonary dysfunction in the aging ventricular septal defect (VSD) patient, we invited adult patients with a congenital VSD and healthy age- and gender-matched controls for static and dynamic spirometry, impulse oscillometry, multiple breath washout, and diffusion capacity for carbon monoxide testing. Primary outcome was forced expiratory volume in 1 second. In total, 30 patients with a surgically corrected VSD (mean age 51 ± 8 years), 30 patients with a small, unrepaired VSD (mean age 55 ± 1 years), and 2 groups of 30 age- and gender-matched, healthy controls (mean age 52 ± 9 years and 55 ± 10 years, respectively) were included. Median age of radical surgery was 6.3 (total range: 1.4 to 54) years and median follow-up after surgery was 40 years (total range: 3.4 to 54). Compared with healthy matched controls, surgically corrected VSD patients had lower forced expiratory volume in 1 second, 87 ± 19% versus 105 ± 14% of predicted, p <0.01, lower forced vital capacity, 92 ± 16% versus 107 ± 13% of predicted, p <0.01, and lower peak expiratory flow, 100 ± 21% versus 122 ± 16% of predicted, p <0.01. Furthermore, corrected VSD patients revealed increased airway resistance in the small airways, 30 ± 22% versus 15 ± 14% of total resistance, p <0.01, and reduced diffusion capacity, 84 ± 12% versus 101 ± 11%, p <0.01. Patients with a small, unrepaired VSD had comparable pulmonary function to their matched controls. In conclusion, VSD patients 40 years of age or older demonstrated significant impaired pulmonary function in terms of reduced dynamic pulmonary function, increased airway resistance in the small airways, and reduced diffusion capacity up to 54 years after defect closure compared with healthy age- and gender-matched controls.

Cardiopulmonary dysfunction in adults with a small, unrepaired ventricular septal defect: A long-term follow-up

BACKGROUND

There are increasing reports of cardiac and exercise dysfunction in adults with small, unrepaired ventricular septal defects (VSDs). The primary aim of this study was to evaluate pulmonary function in adults with unrepaired VSDs, and secondly to assess the effects of 900 μg salbutamol on lung function and exercise capacity.

METHODS

Young adult patients with small, unrepaired VSDs and healthy age- and gender-matched controls were included in a double-blinded, randomised, cross-over study. Participants underwent static and dynamic spirometry, impulse oscillometry, multiple breath washout, diffusion capacity for carbon monoxide, and ergometer bicycle cardiopulmonary exercise test.

RESULTS

We included 30 patients with VSD (age 27 ± 6 years) and 30 controls (age 27 ± 6 years). Patients tended to have lower FEV₁, 104 ± 11% of predicted, compared with healthy controls, 110 ± 14% (p = 0.069). Furthermore, the patient group had lower peak expiratory flow (PEF), 108 ± 20% predicted, compared with the control group, 118 ± 17% (p = 0.039), and showed tendencies towards lower forced vital capacity and increased airway resistance compared with controls. During exercise, the patients had lower oxygen uptake, 35 ± 8 ml/min/kg (vs 47 ± 7 ml/min/kg, p < 0.001), minute ventilation, 1.5 ± 0.5 l/min/kg (vs 2.1 ± 0.3 l/min/kg, p < 0.001) and breath rate, 48 ± 11 breaths/min (vs 55 ± 8 breaths/min, p = 0.008), than controls.

CONCLUSION

At rest, young adults with unrepaired VSDs are no different in pulmonary function from controls. However, when the cardiorespiratory system is stressed, VSD patients demonstrate significantly impaired minute ventilation and peak oxygen uptake, which may be early signs of parenchymal dysfunction and restrictive airway disease. These abnormalities were unaffected by the inhalation of salbutamol.

Disappearance of the shunt and lower cardiac index during exercise in small, unrepaired ventricular septal defects

OBJECTIVES

Clinical studies have revealed decreased exercise capacity in adults with small, unrepaired ventricular septal defects. Increasing shunt ratio and growing incompetence of the aortic and pulmonary valve with retrograde flow during exercise have been proposed as reasons for the previously found reduced exercise parameters. With MRI, haemodynamic shunt properties were measured during exercise in ventricular septal defects.

METHODS

Patients with small, unrepaired ventricular septal defects and healthy peers were examined with MRI during exercise. Quantitative flow scans measured blood flow through ascending aorta and pulmonary artery. Scans were analysed post hoc where cardiac index, retrograde flows, and shunt ratio were determined.

RESULTS

In total, 32 patients (26 ± 6 years) and 28 controls (27 ± 5 years) were included. The shunt ratio was 1.2 ± 0.2 at rest and decreased to 1.0 ± 0.2 at peak exercise, p < 0.01. Aortic cardiac index was lower at peak exercise in patients (7.5 ± 2 L/minute/m2) compared with controls (9.0±2L l/minute/m2), p<0.01. Aortic and pulmonary retrograde flow was larger in patients during exercise, p < 0.01. Positive correlation was demonstrated between aortic cardiac index at peak exercise and previously established exercise capacity for all patients (r = 0.5, p < 0.01).

CONCLUSIONS

Small, unrepaired ventricular septal defects revealed declining shunt ratio with increasing exercise and lower aortic cardiac index. Patients demonstrated larger retrograde flow both through the pulmonary artery and the aorta during exercise compared with controls. In conclusion, adults with unrepaired ventricular septal defects redistribute blood flow during exercise probably secondary to a more fixed pulmonary vascular resistance compared with age-matched peers.