Pulmonary function and ventilatory limitation to exercise in congenital heart disease

A Single Center Observational Study of Spirometry Assessments in Children with Congenital Heart Disease after Surgery

Background: Children with congenital heart disease (CHD) have impaired pulmonary function both before and after surgery; therefore, pulmonary function assessments are important and should be performed both before and after open-heart surgery. This study aimed to compare pulmonary function between variant pediatric CHD types after open-heart surgery via spirometry. Methods: In this retrospective study, the data for forced vital capacity (FVC), forced expiratory volume in the first second (FEV1), and the ratio between FEV1 and FVC (FEV1/FVC) were collected from patients with CHD who underwent conventional spirometry between 2015 and 2017. Results: A total of 86 patients (55 males and 31 females, with a mean age of 13.24 ± 3.32 years) were enrolled in our study. The diagnosis of CHD included 27.9% with atrial septal defects, 19.8% with ventricular septal defects, 26.7% with tetralogy of Fallot, 7.0% with transposition of the great arteries, and 46.5% with other diagnoses. Abnormal lung function was identified by spirometry assessments after surgery. Spirometry was abnormal in 54.70% of patients: obstructive type in 29.06% of patients, restrictive type in 19.76% of patients, and mixed type in 5.81% of patients. More abnormal findings were found in patients who received the Fontan procedure (80.00% vs. 35.80%, p = 0.048). Conclusions: Developing novel therapies to optimize pulmonary function will be critical for improving clinical outcomes.

Exercise Intolerance, Benefits, and Prescription for People Living With a Fontan Circulation: The Fontan Fitness Intervention Trial (F-FIT)-Rationale and Design

Background: Despite developments in surgical techniques and medical care, people with a Fontan circulation still experience long-term complications; non-invasive therapies to optimize the circulation have not been established. Exercise intolerance affects the majority of the population and is associated with worse prognosis. Historically, people living with a Fontan circulation were advised to avoid physical activity, but a small number of heterogenous, predominantly uncontrolled studies have shown that exercise training is safe-and for unique reasons, may even be of heightened importance in the setting of Fontan physiology. The mechanisms underlying improvements in aerobic exercise capacity and the effects of exercise training on circulatory and end-organ function remain incompletely understood. Furthermore, the optimal methods of exercise prescription are poorly characterized. This highlights the need for large, well-designed, multi-center, randomized, controlled trials. Aims and Methods: The Fontan Fitness Intervention Trial (F-FIT)-a phase III clinical trial-aims to optimize exercise prescription and delivery in people with a Fontan circulation. In this multi-center, randomized, controlled study, eligible Fontan participants will be randomized to either a 4-month supervised aerobic and resistance exercise training program of moderate-to-vigorous intensity followed by an 8-month maintenance phase; or usual care (control group). Adolescent and adult (≥16 years) Fontan participants will be randomized to either traditional face-to-face exercise training, telehealth exercise training, or usual care in a three-arm trial with an allocation of 2:2:1 (traditional:telehealth:control). Children (<16 years) will be randomized to either a physical activity and exercise program of moderate-to-vigorous intensity or usual care in a two-arm trial with a 1:1 allocation. The primary outcome is a change in aerobic exercise capacity (peak oxygen uptake) at 4-months. Secondary outcomes include safety, and changes in cardiopulmonary exercise testing measures, peripheral venous pressure, respiratory muscle and lung function, body composition, liver stiffness, neuropsychological and neurocognitive function, physical activity levels, dietary and nutritional status, vascular function, neurohormonal activation, metabolites, cardiac function, quality of life, musculoskeletal fitness, and health care utilization. Outcome measures will be assessed at baseline, 4-months, and 12-months. This manuscript will describe the pathophysiology of exercise intolerance in the Fontan circulation and the rationale and protocol for the F-FIT.

Exercise Testing and Training in Adults With Congenital Heart Disease: A Surgical Perspective

In the current era, the majority of children born with congenital heart disease (CHD) will survive well into adulthood because of major advances in surgical techniques, as well as in critical and medical care. However, reoperation and palliative surgical interventions are increasingly common in the adults with CHD. Tools to risk stratify patients effectively and therapies to improve outcomes are required to optimize the management of adult patients with CHD during the preoperative and postoperative periods and beyond. Exercise testing is an invaluable tool to guide risk stratification. In addition, exercise training in patients with CHD may decrease postoperative complications by enhancing physiological reserve and also has an important role in physical rehabilitation. This review aims to provide individualized recommendations on exercise prescription in patients with CHD in the preoperative and postoperative settings. The response to exercise testing and prognostic implications is also discussed.

Skeletal muscle index determined by bioelectrical impedance analysis is a determinant of exercise capacity and a prognostic predictor in patients with congenital heart disease

BACKGROUND

Patients with congenital heart disease (CHD) reportedly have reduced exercise capacity. Underlying cardiac anatomy and a sedentary lifestyle are thought to be associated with exercise impairment. However, little has been reported regarding the relationship between quantitative body composition and exercise capacity. Bioelectrical impedance analysis (BIA) is a rapid and safe assessment method that has been widely used in clinical research. We hypothesized that bioelectrical impedance parameters are determinants of exercise capacity, and the skeletal muscle index (SMI) determined by BIA is a prognostic predictor in patients with CHD.

METHODS

We conducted a retrospective single-center study of 305 consecutive patients with CHD [median age, 26 years (range 12-60]; 48% males] admitted between 2014 and 2017. The BIA parameters were reviewed, including the edema index (EI, extracellular water to total body water ratio), SMI (skeletal muscle mass/height²), mineral index (MI, mineral mass/height²), percent body fat (%BF), and exercise capacity [peak oxygen uptake (peakVO₂)] via a cardiopulmonary exercise test.

RESULTS

The multivariate analysis revealed a significant correlation between peakVO₂ and EI (r=0.55) and peakVO₂ and SMI (r=0.49). The receiver operating characteristic curve analysis showed that the EI cut-off for peakVO₂<20ml/kg/min was 0.386 [area under the curve (AUC), 0.77; sensitivity, 0.67; specificity 0.76], and the SMI cut-off was 7.6kg/m² (AUC, 0.78; sensitivity, 0.76; specificity 0.75). Compared with patients who had biventricular morphology, patients with single ventricular morphology had a higher EI (mean, 0.381 vs. 0.387, respectively) and lower SMI (8.5 vs. 7.7, respectively), resulting in a lower peakVO₂ (27.1 vs. 20.8, respectively). The Kaplan-Meier analysis showed that a low SMI was associated with an increased risk of future heart failure-related admissions.

CONCLUSIONS

SMI determined by BIA is a determinant of exercise capacity and can be used as a prognostic predictor in patients with CHD.

Impaired pulmonary function and its association with clinical outcomes, exercise capacity and quality of life in children with congenital heart disease

BACKGROUND

Impaired pulmonary function is an independent predictor of mortality in adult congenital heart disease (CHD), but has been scarcely studied in the paediatric CHD population.

AIMS

To compare the pulmonary function of children with CHD to healthy controls, and evaluate its association with clinical outcomes, exercise capacity, and quality of life.

METHODS

Cross-sectional multicentre study among 834 children (555 CHD and 279 control subjects) who underwent a complete spirometry and a cardiopulmonary exercise test (CPET). The 5th centile (Z-score = -1.64) was used to define the lower limit of normal. The association of clinical and CPET variables with spirometry was studied using a multivariate analysis. Children and their parents filled in the Kidscreen health-related quality of life questionnaire.

RESULTS

Forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1) Z-scores values were lower in children with CHD than controls (-0.4 ± 1.5 vs. 0.4 ± 1.3, P < 0.001 and -0.5 ± 1.4 vs. 0.4 ± 1.2, P < 0.001, respectively), without any obstructive airway disorder. Restrictive pattern was more frequent in CHD patients than in controls (20% vs. 4%, P < 0.0001). FVC Z-scores were predominantly impaired in complex CHD, such as heterotaxy (-1.1 ± 0.6), single ventricle (-1.0 ± 0.2), and complex anomalies of the ventricular outflow tracts (-0.9 ± 0.1). In multivariate analysis, FVC was associated with age, body mass index, peak oxygen uptake, genetic anomalies, the number of cardiac surgery and cardiac catheter procedures. FVC and FEV1 correlated with self and proxy-related quality of life scores.

CONCLUSION

These results suggest that pulmonary function should be monitored early in life, from childhood, in the CHD population.

TRIAL REGISTRATION NUMBER

NCT01202916, post-results.

Ventilatory and sensory responses to incremental exercise in adults with a Fontan circulation

Many adults with single-ventricle congenital heart disease who have undergone a Fontan procedure have abnormal pulmonary function resembling restrictive lung disease. Whether this contributes to ventilatory limitations and increased dyspnea has not been comprehensively studied. We recruited 17 Fontan participants and 17 healthy age- and sex-matched sedentary controls. All participants underwent complete pulmonary function testing followed by a symptom-limited incremental cardiopulmonary cycle exercise test with detailed assessments of dyspnea and operating lung volumes. Fontan participants and controls were well matched for age, sex, body mass index, height, and self-reported physical activity levels (all P > 0.05), although Fontan participants had markedly reduced cardiorespiratory fitness and peak work rates ( P < 0.001). Fontan participants had lower values for most pulmonary function measurements relative to controls with 65% of Fontan participants showing evidence of a restrictive ventilatory defect. Relative to controls, Fontan participants had significantly higher breathing frequency, end-inspiratory lung volume (% total lung capacity), ventilatory inefficiency (high ventilatory equivalent for CO2), and dyspnea intensity ratings at standardized absolute submaximal work rates. There were no between-group differences in qualitative descriptors of dyspnea. The restrictive ventilatory defect in Fontan participants likely contributes to their increased breathing frequency and end-inspiratory lung volume during exercise. This abnormal ventilatory response coupled with greater ventilatory inefficiency may explain the increased dyspnea intensity ratings in those with a Fontan circulation. Interventions that enhance the ventilatory response to exercise in Fontan patients may help optimize exercise rehabilitation interventions, resulting in improved exercise tolerance and exertional symptoms.

NEW & NOTEWORTHY This is the first study to comprehensively characterize both ventilatory and sensory responses to exercise in adults that have undergone the Fontan procedure. The majority of Fontan participants had a restrictive ventilatory defect. Compared with well-matched controls, Fontan participants had increased breathing frequency, end-inspiratory lung volume, and ventilatory inefficiency. These abnormal ventilatory responses likely form the mechanistic basis for the increased dyspnea intensity ratings observed in our Fontan participants during exercise.

Non-cardiac comorbidities in adults with inherited and congenital heart disease: report from a single center experience of more than 800 consecutive patients

Background

As a result of improved surgical and therapeutical management, more than 90% of patients with congenital heart disease (CHD) reach adulthood. However, the natural course of CHD is complicated by noncardiac medical problems. Aim of the study was to evaluate noncardiac comorbidities in a contemporary cohort of adults with CHD (ACHD).

Methods

In a tertiary care center for ACHD, 821 consecutive patients, admitted to the outpatient clinic, were evaluated for clinically relevant noncardiac comorbidities.

Results

The consecutively included patients (age: range, 15-80 years; 56% female) represent all types and severity grades of acyanotic and cyanotic CHD. A considerable proportion of ACHD had significant noncardiac comorbidities, which have the potential to profoundly influence the natural course of the underlying disease. In 95.5%, relevant non-cardiac comorbidities were apparent, that could be related to 16 special medical fields as endocrinologic/metabolic disease, gastroenterology/hepatology, gynecology/obstetrics, angiology, orthopedics, neurology/psychiatry and others. Most frequently seen comorbidities were endocrine and metabolic disorders (43.97%).

Conclusions

Non-cardiac comorbidities are increasingly common in ACHD. The data revealed non-cardiac comorbidities as they were presented in the cohort of ACHD seen in a tertiary center. The study proves that ACHD with significant non-cardiac comorbidities need multidisciplinary care by medical organ specialists, aside the congenital cardiologist, with a deep knowledge about congenital heart defects, the special effects of the organ disease on the particular heart defect and, how the heart defect may affect the course of the particular organ disease. The study may create the basis for the development of screening programs for comorbidities in ACHD as well as a multidisciplinary concept for diagnosis and treatment of concomitant disorders or for disease prevention. Particularly disease prevention may improve quality of life as well as the further fate of the affected patients.

When the Heart Is Not to Blame: Managing Lung Disease in Adult Congenital Heart Disease

It is well-recognized now that adult survivors with congenital heart disease (CHD) are at risk for non-cardiac co-morbidities and complications that can impact symptoms and clinical outcomes. Lung disease, in particular, is common in this population, but likely an under-recognized and undertreated cause for long-term morbidity. Abnormal lung function contributes to exercise intolerance and is associated with a higher risk for mortality in this population. The exact mechanisms that contribute to abnormal measurements of lung function are not entirely known, and are likely multifactorial and variable depending on the underlying CHD. Nevertheless, lung disease is a potentially modifiable risk factor in this patient population, the management of which may result in improved clinical outcomes. This review summarizes our current understanding of the prevalence, impact and management of lung disease in adults with CHD.

EXERCISE TOLERANCE, PULMONARY FUNCTION, RESPIRATORY MUSCLE STRENGTH, AND QUALITY OF LIFE IN CHILDREN AND ADOLESCENTS WITH RHEUMATIC HEART DISEASE

OBJECTIVE

Despite the high prevalence of rheumatic heart disease in Brazil, the occurrence of functional impairment in children and adolescents with rheumatic heart disease is not clear. The aim of this study was to evaluate exercise tolerance, respiratory muscle strength, lung function, and quality of life of children and adolescents with rheumatic heart disease.

METHODS

Cross-sectional study, conducted from August to December 2014 with children and adolescents with rheumatic heart disease aged 8 to 16 years. The participants, after completing the socioeconomic, clinical, and quality of life questionnaires were tested by spirometry, manovacuometry and in a 6-minute walk test. The variables and their reference values were compared using the paired Student's t-test. Comparisons between predicted and observed walking distance were done also by Student's t-test, consdiering the categorization of the participants. Correlations between these differences and quantitative variables were assessed by Pearson's coefficient, being significant p<0.05.

RESULTS

All 56 participants had a walked distance lower than predicted (p<0.001). The differences between predicted and observed distances were positively correlated with the baseline heart rate (r=0.3545; p=0.007). Expiratory muscle strength was also lower than the predicted values (p<0,001). Regarding quality of life assessment, the mean scores were 70, 77 and 67% for general, physical, and psychosocial aspects, respectively.

CONCLUSIONS

Children and adolescents with rheumatic heart disease have reduced exercise tolerance, which is related to their higher baseline heart rate; they also show impaired expiratory strength and quality of life.

Extra-cardiac manifestations of adult congenital heart disease

Advancement in correction or palliation of congenital cardiac lesions has greatly improved the lifespan of congenital heart disease patients, resulting in a rapidly growing adult congenital heart disease (ACHD) population. As this group has increased in number and age, emerging science has highlighted the systemic nature of ACHD. Providers caring for these patients are tasked with long-term management of multiple neurologic, pulmonary, hepatic, renal, and endocrine manifestations that arise as syndromic associations with congenital heart defects or as sequelae of primary structural or hemodynamic abnormalities. In this review, we outline the current understanding and recent research into these extra-cardiac manifestations.

Pulmonary hypoplasia associated with congenital heart diseases: a fetal study

Background

Abnormalities of the fetal pulmonary vasculature may affect lung morphogenesis. Postnatal studies have suggested that pulmonary hypoplasia (PH) may be associated with congenital heart diseases (CHDs).

Objective

To determine the prevalence of PH associated with CHDs, and to evaluate whether CHDs with right outflow obstruction were associated with the highest risk of lung growth impairment.

Methods

Between January 2006 and December 2010, fetuses with CHD obtained following the termination of pregnancies due to fetal abnormalities were examined in a prospective manner for the detection of heart and lung defects. CHDs were classified into five pathophysiological groups. Lung weight (LW), body weight (BW), and LW/BW ratio were analyzed for each case. The expression of CD31 and VEGF in the lung was evaluated by immunohistochemistry.

Results

Fetuses with CHDs and right outflow obstruction had significantly lower LW for a given BW, and significantly lower LW/BW ratios for a given gestational age. When defining PH as a fetal LW/BW ratio <0.015 before 28 weeks, and <0.012 after 28 weeks, PH was detected in 15 of the 119 fetuses analyzed (13%). It was significantly associated with CHD with right outflow obstruction, independently of chromosomal abnormalities and associated extracardiac abnormalities (p<0.03). Right outflow obstruction was detected in 60% of the fetuses with CHD and PH, but in only 32% of those with CHD but no PH. In fetuses with right outflow obstruction, no difference was observed between those with PH and those without PH, in terms of the ratio of pulmonary artery diameter to aortic diameter, lung CD31 expression, or lung VEGF expression.

Conclusion

CHDs with right outflow obstruction are a significant risk factor for prenatally acquired PH. The occurrence of fetal PH is not correlated with abnormalities of the pulmonary vasculature, suggesting the involvement of perfusion-independent mechanisms.

Restrictive lung function in pediatric patients with structural congenital heart disease

OBJECTIVES

We sought to describe the prevalence of restrictive lung function in structural congenital heart disease and to determine the effect of cardiothoracic surgical intervention.

METHODS

The data from a retrospective review of the spirometry findings from pediatric patients with structural congenital heart disease were compared with the data from 220 matched controls. Restrictive lung function was defined as a forced vital capacity of <80%, with a preserved ratio of the forced expiratory volume in the first second to forced vital capacity of >80%.

RESULTS

Of the children with congenital heart disease, 20% met the criteria for restrictive lung function compared with 13.2% of the controls (P = .03). The prevalence in those with congenital heart disease without a surgical history was similar to that of the controls (odds ratio, 0.62; 95% confidence interval, 0.34-1.13). Restrictive lung function was more likely if surgical intervention had occurred within the first year of life (odds ratio, 1.96; 95% confidence interval, 1.08-3.55; P < .0001). Those who had undergone both sternotomy and thoracotomy had a greater prevalence of restrictive lung function than those who had undergone sternotomy or thoracotomy alone (54.2% vs 25.6% and 23.5%, respectively; P < .0001). The prevalence of restrictive lung function increased significantly with each additional surgical intervention (odds ratio, 1.61; 95% confidence interval, 1.29-2.01; P < .0001).

CONCLUSIONS

Restrictive lung function was more prevalent in those with congenital heart disease after cardiothoracic surgical intervention than in the controls or patients without surgical intervention. The prevalence was also greater with surgical intervention at an earlier age. The risk was equivalent when sternotomy alone was compared with thoracotomy alone but was significantly greater when both sternotomy and thoracotomy were performed. The risk increased with each additional surgery performed.

Respiratory syncytial virus infections in infants and children with congenital heart disease: update on the evidence of prevention with palivizumab

PURPOSE OF REVIEW

Lower respiratory tract infections multiply morbidity and mortality within patients with significant congenital heart disease (CHD). For respiratory syncytial virus (RSV), one of the most important pathogens, immunoprophylaxis with palivizumab has successfully been introduced. The question is which patients will benefit most from this costly preventive treatment.

RECENT FINDINGS

The era after the introduction of palivizumab has revealed a steep decrease in mortality. The markers of success - hospital stays, admission to the intensive care unit, days on mechanical ventilation, and death - consistently favor immunoprophylaxis. The key point of treatment success remains in all cases a careful patient selection, adherence to a time limit of 30 days between the injections and early use after cardiac surgery with cardiopulmonary bypass, as well as avoidance of nosocomial-acquired infections. Preventive therapy with palivizumab in patients with CHD has been investigated in terms of operating efficiency - with the lowest costs per quality-adjusted life years compared with preterm infants with or without bronchopulmonary dysplasia.

SUMMARY

The burden of RSV disease will decline, once a vaccine is available. Meanwhile, immunoprophylaxis with palivizumab is a useful tool for high-risk patients to reduce comorbidity and fatal outcome. Pharmacoeconomic considerations measuring quality-adjusted life years indicate important information about cost-effectiveness.

Does early tetralogy of Fallot total correction give better final lung volumes?

Background:

Pulmonary blood flow may affect lung development in adulthood. Early total correction of tetralogy of Fallot may affect development of final lung volumes. We evaluated the effect of age at total correction on lung volumes years after the operation.

Methods:

In a retrospective cohort study on patients with totally corrected tetralogy of Fallot (mean age, 13.40 years at the time of follow-up), forced vital capacity, slow vital capacity, forced expiratory volume in 1 s, and other parameters were measured 154.8 ± 46.25 months after the operation. Comparison were made of 3 groups: ≤2-, 2–8-, and >8-years old at the time of total correction surgery.

Results:

Among 322 enrolled patients, the mean values of the follow-up spirometry results in ≤2-, 2–8-, >8-year-olds and the percentage of predicted values were respectively: vital capacity: 4.46 ± 0.57 L (107% ± 10.96%), 3.89 ± 0.58 L (91.10% ± 12.25%), 3.25 ± 0.48 L (82.35% ± 10.62%), p < 0.001; forced vital capacity: 4.28 ± 0.63 L (95.90% ± 18.77%), 3.76 ± 0.58 L (90.83% ± 12.52%), 3.14 ± 0.49 L (83.26% ± 11.71%), p < 0.001; forced expiratory volume in 1 s: 4.22 ± 0.63 L (104.84% ± 13.64%), 3.66 ± 0.58 L (90.61% ± 12.59%), 3.02 ± 0.48 L (84.31% ± 12%), p < 0.001.

Conclusion:

Early correction of defects or reestablishments of perfusion of tetralogy of Fallot before completion of lung development might improve final adulthood lung volumes and capacities. It is better to consider total correction for all tetralogy of Fallot patients below 2-years old, or at least below 8-years old, if it is technically possible.

Extracardiac complications in adults with congenital heart disease

With the increasing number of adults living with repaired, or unrepaired, congenital heart disease, there is a growing incidence of extracardiac comorbidities. These comorbidities can affect various organ systems in complex ways, and may have a significant impact on a patient's quality of life and survival. Many of these potential complications may go undiagnosed until there is already a significant bearing on the patient's life. Therefore, it is important for physicians who care for the adult congenital patient to be mindful of these potential extracardiac complications, and actively assess for these complications in their adult congenital practice. Continued research to identify modifiable risk factors is needed so that both preventative and therapeutic management options for these extracardiac complications may be developed.

Renal dysfunction is common among adults after palliation for previous tetralogy of Fallot

Long-term survival after tetralogy of Fallot (TOF) repair is excellent. However, little is published regarding late noncardiac complications. This study aimed to determine the prevalence and risk factors for renal dysfunction among adults after TOF repair. For this study, 56 adult patients with complete repair of TOF were identified, and their charts were retrospectively reviewed. An estimated glomerular filtration rate (eGFR) for each patient was calculated using the Modification of Diet in Renal Disease formula (MDRD). Using each patient's eGFR, he or she was classified into stages based on the National Kidney Foundation chronic kidney disease (CKD) staging. Clinical parameters were compared among patients with and those without renal dysfunction to identify risk factors for renal impairment. The median estimated eGFR rate for the cohort was 78 ml/min/1.73 m(2). Based on the National Kidney Foundation CKD staging system, 54 % of the patients had at least stage 2 chronic renal disease. The risk factors identified were hypertension (p < 0.01), type 2 diabetes mellitus (p < 0.05), longer follow-up evaluation (p < 0.005), older age at complete repair (p < 0.05), and use of daily diuretics (p < 0.05). After repair of TOF, renal dysfunction is common at late follow-up evaluation. The study findings show the importance of routine assessment of renal function and the need to limit or avoid future episodes of acute kidney injury in this at-risk population.

Restrictive lung disease is an independent predictor of exercise intolerance in the adult with congenital heart disease

BACKGROUND/OBJECTIVES

Following repair of congenital heart disease (CHD), adult patients are at risk for reduced exercise capacity. Restrictive lung disease (RLD) may contribute to reduced exercise capacity in this population. The aim of this study was to determine the prevalence of RLD and its impact on exercise tolerance in the adult with CHD.

METHODS

One hundred consecutive adult patients with CHD, who underwent routine cardiopulmonary exercise testing with spirometry, were evaluated. Clinical data were obtained by retrospective chart review.

RESULTS

Patients from 10 major diagnostic groups were identified. The median age for the cohort was 31 years (range 18-63) and included 43 males and 57 females. Most patients, 79%, had at least one previous surgical procedure. Based on spirometry and flow/volume loops, 50 patients were classified as normal pulmonary function, 44 patients had patterns suggestive of RLD, 4 suggestive of mixed (obstructive and restrictive), and 2 indeterminate. Risk factors associated with RLD include history of multiple thoracotomies (odds ratio = 9.01, P =.05) and history of atrial arrhythmias (odd ratio = 4.25, P =.05). Overall, 56% of the patients had abnormal exercise capacity. Spirometry suggestive of RLD was a significant risk factor for decreased exercise capacity (odds ratio = 3.65, P =.03). Patients with spirometry suggesting RLD also had lower exercise duration (P =.004) and a higher New York Heart Association Functional Class (P =.02). History of previous surgery and decreased heart rate reserve were also significant risk factors for decreased exercise capacity.

CONCLUSION

Abnormal spirometry suggestive of RLD is common in the adult with CHD and is a significant risk factor for decreased exercise tolerance in this population. Further studies are needed to evaluate the relationship between RLD and exercise intolerance and its relationship to mortality in the adult with CHD.

Urinary interleukin-18 and urinary neutrophil gelatinase-associated lipocalin predict acute kidney injury following pulmonary valve replacement prior to serum creatinine

BACKGROUND

It is becoming increasingly recognized that manifestations of congenital heart disease (CHD) extend beyond the cardiovascular system. The factors contributing to renal dysfunction in patients with CHD are multifactorial, with acute kidney injury (AKI) at time of cardiac surgery playing a major role. AKI is often diagnosed based on changes in serum creatinine and estimated glomerular filtration rate (eGFR). Such measurements are often late and imprecise. Recent data indicate that urinary biomarkers interleukin-18 (IL-18) and neutrophil gelatinase-associated lipocalin (NGAL) are earlier markers of AKI. We sought to determine the efficacy of urinary IL-18 and NGAL for detecting early AKI in patients undergoing surgical pulmonary valve replacement (PVR).

METHODS

Twenty patients presenting for surgical PVR with a history of previous repair of a conotruncal anomaly were enrolled. Preoperative clinical data were measured and urine samples and serum creatinine were collected at 6, 12, 24, and 72 hours post bypass. Urine was evaluated for NGAL and IL-18. AKI was determined using the Risk, Injury, Failure, Loss and End Stage Renal Disease (RIFLE) classification system.

RESULTS

Using the RIFLE classification system, seven patients (35%) were found to have AKI defined as a drop in the eGFR or an increase in serum creatinine. All seven patients with AKI had marked increase from preoperative baseline in urine IL-18 (sixfold) and NGAL (26-fold). Using NGAL and IL-18, AKI was detected at 6 hours postoperatively, resulting in AKI being identified 12-36 hours prior to detection by conventional methods. No preoperative predictors for AKI were identified.

CONCLUSION

Both NGAL and IL-18 are early predictive biomarkers of AKI, and both increase in tandem after surgical PVR. Importantly, both rise before an increase in creatinine or a decrease in eGFR is present. Monitoring both biomarkers may allow for earlier detection and subsequent interventions to prevent AKI at time of surgery for CHD.

Pulmonary limitation to exercise after repair of D-transposition of the great vessels: atrial baffle versus arterial switch

This study evaluated resting pulmonary function and its impact on exercise capacity after atrial baffle (BAFFLE) and arterial switch (SWITCH) repair of D-transposition of the great vessels (DTGV). Previously decreased exercise capacity in DTGV patients has been primarily attributed to cardiovascular limitations, whereas pulmonary limitations have largely been overlooked. Resting flow volume loops were compared for BAFFLE (n = 34) and SWITCH (n = 32) patients. Peak exercise variables were compared for BAFFLE (n = 30) and SWITCH (n = 25). Lung disease (restrictive and/or obstructive) was present in 53% of DTGV patients (BAFFLE 62% and SWITCH 44%; p = 0.14). BAFFLE patients had a normal breathing reserve, whereas that of SWITCH patients was decreased (27.3 ± 28.3 vs. 13.0 ± 19.2; p = 0.04). BAFFLE patients attained a lower percent of predicted peak oxygen pulse (82.7 ± 20.5% vs. 94.7 ± 19.3%; p = 0.04) and peak oxygen consumption (VO(2peak)) (26.6 ± 6.7 ml/kg/min vs. 37.3 ± 8.5 ml/kg/min; p < 0.01) than SWITCH patients. Patients after surgical repair for DTGV have an underappreciated occurrence of lung disease, even post-SWITCH. SWITCH patients have diminished breathing reserves, suggesting a pulmonary limitation to VO(2peak). BAFFLE patients have lower VO(2peaks), greater breathing reserves, and lower oxygen pulses than SWITCH patients, suggesting a cardiac limitation to peak aerobic capacity with probable secondary pulmonary limitations. Treating underlying lung disease in symptomatic patients after repair of DTGV may improve functional status.

Myocardial perfusion and exercise capacity 12 years after arterial switch surgery for D-transposition of the great arteries

Peak exercise myocardial perfusion was evaluated in patients with D-transposition of the great arteries 12 years after the arterial switch operation (SWITCH) to evaluate coronary perfusion. Gas-exchange measurements were used to assess cardiac limiting factors to exercise capacity in SWITCH patients when compared to healthy gender-matched controls (CON). Peak myocardial perfusion was evaluated in 42 patients 12 years post-SWITCH, using technetium-99 m (Tetrofosmin). SWITCH exercise data was compared to 42 gender-matched controls (CON). One symptomatic and one asymptomatic SWITCH patient had abnormal exercise myocardial perfusion; both patients had variant coronary anatomy preoperatively. SWITCH patients had lower VO(2peak) (p < 0.01), peak heart rates (p = 0.01), percentages of age-predicted peak heart rates (p < 0.01), and peak oxygen pulses indexed to body surface area (p < 0.01) than CON patients. Exercise testing with myocardial perfusion imaging helped to identify the rare SWITCH patient with coronary insufficiencies. This study demonstrates that exercise testing with myocardial perfusion scans can help identify patients at risk for myocardial events. This study also demonstrated that SWITCH patients have a mildly diminished VO(2peak) when compared to CON patients.