Pathogenesis of the glomerular abnormality in cyanotic congenital heart disease

Exploring kidney biopsy findings in congenital heart diseases: Insights beyond cyanotic nephropathy

BACKGROUND

The association between congenital heart disease and chronic kidney disease is well known. Various mechanisms of kidney damage associated with congenital heart disease have been established. The etiology of kidneydisease has commonly been considered to be secondary to focal segmental glomerulosclerosis (FSGS), however, this has only been demonstrated in case reports and not in observational or clinical trials.

AIM

To identify baseline and clinical characteristics, as well as the findings in kidney biopsies of patients with congenital heart disease in our hospital.

METHODS

This is a retrospective observational study conducted at the Nephrology Department of the National Institute of Cardiology "Ignacio Chávez". All patients over 16 years old who underwent percutaneous kidney biopsy from January 2000 to January 2023 with congenital heart disease were included in the study.

RESULTS

Ten patients with congenital heart disease and kidney biopsy were found. The average age was 29.00 years ± 15.87 years with pre-biopsy proteinuria of 6193 mg/24 h ± 6165 mg/24 h. The most common congenital heart disease was Fallot's tetralogy with 2 cases (20%) and ventricular septal defect with 2 (20%) cases. Among the 10 cases, one case of IgA nephropathy and one case of membranoproliferative glomerulonephritis associated with immune complexes were found, receiving specific treatment after histopathological diagnosis, delaying the initiation of kidney replacement therapy. Among remaining 8 cases (80%), one case of FSGS with perihilar variety was found, while the other 7 cases were non-specific FSGS.

CONCLUSION

Determining the cause of chronic kidney disease can help in delaying the need for kidney replacement therapy. In 2 out of 10 patients in our study, interventions were performed, and initiation of kidney replacement therapy was delayed. Prospective studies are needed to determine the usefulness of kidney biopsy in patients with congenital heart disease.

Kidney disease and congenital heart disease: Partnership for life

The literature on the relationship between kidney and cardiovascular diseases is continuously expanding. Scientists have elucidated many of the neurohormonal and hemodynamic pathways involved in cardiorenal disease. However, little is known about kidney disease in patients with congenital heart disease. Given advances in the medical and surgical care of this highly complex patient population, survival rates have dramatically improved leading to a higher percentage of adults living with congenital heart disease. Accordingly, a noticeable increase in the prevalence of kidney disease is appreciated in these patients. Some of the main risk factors for developing chronic kidney disease in the adult congenital heart disease population include chronic hypoxia, neurohormonal derangements, intraglomerular hemodynamic changes, prior cardiac surgeries from minimally invasive to open heart surgeries with ischemia, and nephrotoxins. Unfortunately, data regarding the prevalence, pathophysiology, and prognosis of chronic kidney disease in the adult congenital heart disease population remain scarce. This has led to a lack of clear recommendations for evaluating and managing kidney disease in these patients. In this review, we discuss contemporary data on kidney disease in adults with congenital heart disease in addition to some of the gaps in knowledge we face. The article highlights the delicate interaction between disease of the heart and kidneys in these patients, and offers the practitioner tools to more effectively manage this vulnerable population.

Pediatric Patients Undergoing a Fontan Operation or with a High RACHS-1 Score Require Monitoring for Chronic Kidney Disease in Early Childhood

Although the number of pediatric patients with long-term survival following cardiac surgery is increasing, concerns regarding chronic kidney disease (CKD) after surgery are growing. We examined the frequency of and risk factors for pediatric CKD development in patients with congenital heart disease (CHD) at least 2 years after cardiac surgery. This was a cross-sectional study of 147 patients who underwent open-heart surgery for CHD at Kagoshima University Hospital from April 2010 to March 2017. Data on demographics, acute kidney injury after cardiac surgery, cyanotic heart disease, Fontan circulation, medications in the perioperative period, and Risk Adjustment for Congenital Heart Surgery-1 (RACHS-1) category were recorded. CKD was defined using the current classification system described in the National Kidney Foundation's Kidney Disease Outcomes Quality Initiative and assessed during early childhood within 2-3 years of cardiac surgery. Statistical analyses were performed using SPSS Statistics for Windows version 25.0. We consecutively enrolled 147 patients, of whom 22 (15.0%) had CKD, all with stage-2 severity. Among patients with CKD, a higher proportion underwent Fontan surgery (P < 0.001), a higher proportion had cyanotic heart disease (P = 0.009), and the RACHS-1 category was high (P = 0.003). Patients with CKD appeared more frequently than patients without CKD in RACHS-1 categories 3, 5, and 6. It is essential to evaluate renal function longitudinally and monitor for CKD, given that patients who underwent Fontan surgery or complicated surgery in infancy have a high rate of developing postoperative CKD in early childhood.

Hepatic and Renal Consequences of Single Ventricle Physiology Palliated with the Fontan Operation

Over time the long-term survival has dramatically increased for patients with complex congenital heart disease who undergo the Fontan operation. With this increased survival, it has become apparent that such a circulation has important consequences for other organ systems, particularly the liver and kidney. The adverse milieu created by chronic venous hypertension, low cardiac output and an inflammatory state contribute to the pathologic changes observed in the liver and kidneys over the long-term in Fontan patients. The clinical importance of these hepatic and renal comorbidities have only recently begun to be recognized in the context of increasing life expectancy in this population. The objectives of this review are: i) to provide an overview of the pathophysiology of the Fontan circulation and how liver and kidney disease evolve in this setting; ii) to summarize the current evidence base as it relates to the diagnostic approach to liver and kidney disease in Fontan patients; and, iii) to discuss the therapeutic approaches to Fontan associated liver and kidney disease. Given that this is a very active area of research in congenital heart disease, we have identified knowledge gaps and priority research areas to improve the care of Fontan patients. These include: i) establishing the optimal diagnostic tests to detect and track liver and kidney disease change over time,; ii) determining what treatable risk factors contribute to the development of liver and kidney disease; and, iii) evaluating therapies to prevent or slow progression of liver and kidney disease.

COVID-19 in Adults With Congenital Heart Disease

Background

Adults with congenital heart disease (CHD) have been considered potentially high risk for novel coronavirus disease-19 (COVID-19) mortality or other complications.

Objectives

This study sought to define the impact of COVID-19 in adults with CHD and to identify risk factors associated with adverse outcomes.

Methods

Adults (age 18 years or older) with CHD and with confirmed or clinically suspected COVID-19 were included from CHD centers worldwide. Data collection included anatomic diagnosis and subsequent interventions, comorbidities, medications, echocardiographic findings, presenting symptoms, course of illness, and outcomes. Predictors of death or severe infection were determined.

Results

From 58 adult CHD centers, the study included 1,044 infected patients (age: 35.1 ± 13.0 years; range 18 to 86 years; 51% women), 87% of whom had laboratory-confirmed coronavirus infection. The cohort included 118 (11%) patients with single ventricle and/or Fontan physiology, 87 (8%) patients with cyanosis, and 73 (7%) patients with pulmonary hypertension. There were 24 COVID-related deaths (case/fatality: 2.3%; 95% confidence interval: 1.4% to 3.2%). Factors associated with death included male sex, diabetes, cyanosis, pulmonary hypertension, renal insufficiency, and previous hospital admission for heart failure. Worse physiological stage was associated with mortality (p = 0.001), whereas anatomic complexity or defect group were not.

Conclusions

COVID-19 mortality in adults with CHD is commensurate with the general population. The most vulnerable patients are those with worse physiological stage, such as cyanosis and pulmonary hypertension, whereas anatomic complexity does not appear to predict infection severity.

Evaluation of renal injury in children with uncorrected CHDs with significant shunt using urinary neutrophil gelatinase-associated lipocalin

BACKGROUND

CHDs can be complicated by renal injury which worsens morbidity and mortality. Urinary neutrophil gelatinase-associated lipocalin, a sensitive and specific biomarker of renal tubular injury, has not been studied in children with uncorrected CHDs. This study evaluated renal injury in children with uncorrected CHDs using this biomarker.

METHODS

The patients were children with uncorrected CHDs with significant shunt confirmed on echocardiogram with normal renal ultrasound scan, in the paediatric cardiology clinic of a tertiary hospital. The controls were age-matched healthy children recruited from general practice clinics. Information on bio-data and socio-demographics were collected and urine was obtained for measurement of urinary neutrophil gelatinase-associated lipocalin levels.

RESULTS

A total of 65 children with uncorrected CHDs aged 2 to 204 months were recruited. Thirty-one (47.7%) were males while 36 (55.4%) had acyanotic CHDs. The median urinary neutrophil gelatinase-associated lipocalin level of patients of 26.10 ng/ml was significantly higher than controls of 16.90 ng/ml (U = 1624.50, p = 0.023). The median urinary neutrophil gelatinase-associated lipocalin level of patients with cyanotic and acyanotic CHDs were 30.2 ng/ml and 22.60 ng/ml respectively; (Mann-Whitney U = 368.50, p = 0.116). The prevalence of renal injury using 95th percentile cut-off value of urinary neutrophil gelatinase-associated lipocalin was 16.9%. Median age of patients with renalinjury was 16 (4-44) months.

CONCLUSIONS

Children with uncorrected CHDs have renal injury detected as early as infancy. The use of urinary neutrophil gelatinase-associated lipocalin in early detection of renal injury in these children may enhance early intervention and resultant prevention of morbidity and reduction in mortality.

Hypertrophic osteoarthropathy

Hypertrophic osteoarthropathy (HOA) is an orphan syndrome characterized by abnormal proliferation of the skin and osseous tissues at the distal parts of the extremities. The main clinical features are: a peculiar bulbous deformity of the tips of the digits conventionally described as "clubbing," periosteal proliferation of the tubular bones, and synovial effusions. In most instances, HOA develops a reaction to a severe internal illness, such as lung cancer, cyanotic heart disease, or liver cirrhosis. There is a subgroup of patients who do not have underlying pathology. Such cases are classified as having primary HOA. Digital clubbing is easy to recognize. Any patient with newly developed digital clubbing should undergo careful search for an underlying illness with special attention to intra-thoracic pathologies. Painful HOA is treated with non-steroidal anti-inflammatory medications. Vascular endothelial growth factor and prostaglandin E2 have been proposed as key bone proliferating mediators.

Association of Albuminuria With Major Adverse Outcomes in Adults With Congenital Heart Disease: Results From the Boston Adult Congenital Heart Biobank

Importance

Albuminuria is associated with adverse outcomes in diverse groups of patients, but the importance of albuminuria in the emerging population of increasingly complex adults with congenital heart disease (ACHD) remains unknown.

Objective

To assess the prevalence, risk factors, and prognostic implications of albuminuria in ACHD.

Design, Setting, and Participants

This prospective study assessed a cohort of ambulatory patients aged 18 years and older who were examined at an ACHD referral center and enrolled in the Boston ACHD Biobank between May 17, 2012, to August 5, 2016. Albuminuria was defined as an urine albumin-to-creatinine (ACR) ratio of 30 mg/g or more.

Main Outcomes and Measures

Death or nonelective cardiovascular hospitalization, defined as overnight admission for heart failure, arrhythmia, thromboembolic events, cerebral hemorrhage, and/or disease-specific events.

Results

We measured the ACR of 612 adult patients with CHD (mean [SD] age, 38.6 [13.4] years; 308 [50.3%] women). Albuminuria was present in 106 people (17.3%) and was associated with older age (patients with ACR <30 mg/g: mean [SD]: 37.5 [13.2] years; vs patients with ACR ≥30 mg/g: 43.8 [13.1] years; P < .001), presence of diabetes mellitus (ACR <30 mg/g: 13 of 506 [2.6%]; vs ≥30 mg/g: 11 of 106 [10.4%]; P < .001), lower estimated glomerular filtration rate (ACR <30 mg/g: median [interquartile range (IQR)]: 103.3 [90.0-116.4] mL/min/1.73 m2; ACR ≥30 mg/g: 99.1 [78.8-108.7] mL/min/1.73 m2; P = .002), and cyanosis (ACR <30 mg/g: 23 of 506 [5.1%]; vs ACR ≥30 mg/g: 21 of 106 [22.6%]; P < .001). After a mean (SD) follow-up time of 270 (288) days, 17 patients (2.5%) died, while 68 (11.1%) either died or experienced overnight inpatient admission. Albuminuria predicted outcome, with 30 of 106 patients with albuminuria (28.3%) affected vs 38 of 506 patients without albuminuria (7.5%; hazard ratio [HR], 3.0; 95% CI, 1.9-4.9; P < .001). Albuminuria was also associated with increased mortality (11 of 106 [10.4%]; vs 6 of 506 [1.2%] in patients with and without albuminuria, respectively; HR, 6.4; 95% CI, 2.4-17.3; P < .001). Albuminuria was associated with the outcomes only in patients with a biventricular circulation (HR, 4.5; 95% CI, 2.5-8.0) and not those with single-ventricle circulation (HR, 1.0; 95% CI, 0.4-2.8; P = 0.01 compared with biventricular circulation group). Among 133 patients (21.7%) in NYHA functional class 2, albuminuria was strongly associated with death or nonelective hospitalization.

Conclusions and Relevance

Albuminuria is common and is associated with increased risk for adverse outcome in patients with ACHD with biventricular circulation. Albuminuria appears especially useful in stratifying risk in patients categorized as NYHA functional class 2.

Evaluation and Management of the Child and Adult With Fontan Circulation: A Scientific Statement From the American Heart Association

It has been 50 years since Francis Fontan pioneered the operation that today bears his name. Initially designed for patients with tricuspid atresia, this procedure is now offered for a vast array of congenital cardiac lesions when a circulation with 2 ventricles cannot be achieved. As a result of technical advances and improvements in patient selection and perioperative management, survival has steadily increased, and it is estimated that patients operated on today may hope for a 30-year survival of >80%. Up to 70 000 patients may be alive worldwide today with Fontan circulation, and this population is expected to double in the next 20 years. In the absence of a subpulmonary ventricle, Fontan circulation is characterized by chronically elevated systemic venous pressures and decreased cardiac output. The addition of this acquired abnormal circulation to innate abnormalities associated with single-ventricle congenital heart disease exposes these patients to a variety of complications. Circulatory failure, ventricular dysfunction, atrioventricular valve regurgitation, arrhythmia, protein-losing enteropathy, and plastic bronchitis are potential complications of the Fontan circulation. Abnormalities in body composition, bone structure, and growth have been detected. Liver fibrosis and renal dysfunction are common and may progress over time. Cognitive, neuropsychological, and behavioral deficits are highly prevalent. As a testimony to the success of the current strategy of care, the proportion of adults with Fontan circulation is increasing. Healthcare providers are ill-prepared to tackle these challenges, as well as specific needs such as contraception and pregnancy in female patients. The role of therapies such as cardiovascular drugs to prevent and treat complications, heart transplantation, and mechanical circulatory support remains undetermined. There is a clear need for consensus on how best to follow up patients with Fontan circulation and to treat their complications. This American Heart Association statement summarizes the current state of knowledge on the Fontan circulation and its consequences. A proposed surveillance testing toolkit provides recommendations for a range of acceptable approaches to follow-up care for the patient with Fontan circulation. Gaps in knowledge and areas for future focus of investigation are highlighted, with the objective of laying the groundwork for creating a normal quality and duration of life for these unique individuals.

Altered in utero kidney development in newborns with congenital heart disease

BACKGROUND

It is known that the heart is not the only organ affected in congenital heart disease (CHD); there is growth restriction of both the brain and the whole body. The protective mechanism of "the brain-sparing phenomenon" re-directs blood flow toward the growing brain in fetuses with CHD. We hypothesized that these changes would result in impaired fetal kidney growth.

METHODS

The preoperative ultrasound measurements of kidney length were obtained retrospectively from 452 neonates requiring surgery for CHD. Percentiles were generated based on regression analysis of normative kidney length from three datasets according to both corrected gestational age and to birthweight.

RESULTS

As a cohort, neonates with CHD have significantly enlarged kidneys, with a mean percentile ranging from 54.1-72.7 (p < 0.001), depending on the three normal population datasets used for comparison. The kidneys of neonates with left heart obstruction were consistently demonstrated to be greater than normal, unlike those with cyanotic heart disease which were shown to have either normal or enlarged kidneys, depending on the reference population used.

CONCLUSIONS

The kidneys of newborns with CHD are not reduced in size, and on average are larger than normal. The nature of this size discrepancy and its subsequent clinical significance is unknown.

Medium-term follow-up of renal function in hypoxaemic congenital heart disease patients

Introduction Hypoxaemic congenital heart disease (CHD) patients are at higher risk of complications. The aim of this study was to compare and follow-up blood and 24-hour urine analytical data in hypoxaemic and non-hypoxaemic CHD patients.

METHODS

The inclusion criteria for this study were as follows: patients older than 14 years of age with a structural CHD with or without associated hypoxaemia.

RESULTS

In total, 27 hypoxaemic and 48 non-hypoxaemic CHD patients were included in order to compare blood and 24-hour urine analytical data. Among hypoxaemic patients, 13 (48.1%) were male, two (7.4%) had diabetes mellitus, one of whom was a smoker, one (3.7%) had systemic arterial hypertension, and 11 (40.7%) showed pulmonary arterial hypertension. The mean follow-up time was 3.1±1.9 years. Hypoxaemic CHD patients showed higher proteinuria concentrations (g/24 hours) (0.09 (0.07; 0.46) versus 0.08 (0.07; 0.1), p=0.054) and 24-hour albumin excretion rate (µg/min) (16.5 (11.2; 143.5) versus 4.4 (0.0; 7.6), p<0.001) compared with non-hypoxaemic CHD patients; however, no significant differences were found in the proteinuria levels and in the 24-hour albumin excretion rate in CHD patients with associated hypoxaemia, both at baseline and at follow-up. When divided into groups, hypoxaemic patients with palliative shunts showed significantly higher proteinuria concentrations compared with hypoxaemic patients not operated on or with Fontan procedures (p=0.01). No significant differences were seen in 24-hour proteinuria and 24-hour albumin excretion rate during the follow-up of patients with palliative shunts.

CONCLUSIONS

Hypoxaemic CHD patients have significant higher 24-hour proteinuria concentration and 24-hour albumin excretion rate compared with non-hypoxaemic CHD patients. Among hypoxaemic CHD patients, those with palliative shunts showed the highest 24-hour proteinuria concentrations.

Chronic kidney disease in congenital heart disease patients: a narrative review of evidence

Purpose of review

Patients with congenital heart disease have a number of risk factors for the development of chronic kidney disease (CKD). It is well known that CKD has a large negative impact on health outcomes. It is important therefore to consider that patients with congenital heart disease represent a population in whom long-term primary and secondary prevention strategies to reduce CKD occurrence and progression could be instituted and significantly change outcomes. There are currently no clear guidelines for clinicians in terms of renal assessment in the long-term follow up of patients with congenital heart disease. Consolidation of knowledge is critical for generating such guidelines, and hence is the purpose of this view. This review will summarize current knowledge related to CKD in patients with congenital heart disease, to highlight important work that has been done to date and set the stage for further investigation, development of prevention strategies, and re-evaluation of appropriate renal follow-up in patients with congenital heart disease.

Sources of information

The literature search was conducted using PubMed and Google Scholar.

Findings

Current epidemiological evidence suggests that CKD occurs in patients with congenital heart disease at a higher frequency than the general population and is detectable early in follow-up (i.e. during childhood). Best evidence suggests that approximately 30 to 50 % of adult patients with congenital heart disease have significantly impaired renal function. The risk of CKD is higher with cyanotic congenital heart disease but it is also present with non-cyanotic congenital heart disease. Although significant knowledge gaps exist, the sum of the data suggests that patients with congenital heart disease should be followed from an early age for the development of CKD.

Implications

There is an opportunity to mitigate CKD progression and negative renal outcomes by instituting interventions such as stringent blood pressure control and reduction of proteinuria. There is a need to invest time, thought and money to fill existing knowledge gaps to improve health outcomes in this population. This review should serve as an impetus for generation of follow-up guidelines of kidney health evaluation in patients with congenital heart disease.

Proteinuria and clinical outcome in CHD patients

INTRODUCTION

CHD patients, especially those with associated hypoxaemia, usually have some level of renal function impairment, even though they are relatively young. The aim of the study was to evaluate those clinical and analytical factors that may contribute to microalbuminuria and determine the association of 24-hour proteinuria with thrombotic events and mortality.

METHODS

A total of 251 CHD patients were studied and demographic characteristics, blood test, and 24-hour urinalysis were analysed.

RESULTS

Of the patients, 221 were non-hypoxaemic, and 30 were hypoxaemic (oxygen saturation of 84.3±5.9%). Of the non-hypoxaemic patients, 30 (13.6%), and of the hypoxaemic patients 9 (30%), showed proteinuria (>0.15 g/24 hours) (p=0.028). Hypoxaemic CHD patients also showed higher haematocrit (%) (50.7 (34.6; 72.1) versus 42.8 (34.6; 48.9), p<0.001), serum creatinine (mg/dl) (1.07±0.2 versus 0.96±1.9, p=0.004), microalbuminuria (mg/dl/24 hours) (1.2 (0.0; 261.5) versus 0.5 (0.0; 4.37), p<0.001), proteinuria (gr/24 hours) (1.0 (0.4; 3.1) versus 0.08 (0.04; 0.52), p=0.043), and N-terminal pro-B-type natriuretic peptide (pg/ml) (417.8 (35.7; 8534.0) versus 44.9 (0.0; 670.5), p<0.001) concentrations than non-hypoxaemic CHD patients. During a median follow-up of 26.0 (16.9; 57.7) months, five patients died - one patient had 24-hour proteinuria and four patients did not (p=0.581) - and three patients had some type of thrombosis - two patients had 24-hour proteinuria and one patient did not (p=0.014). Kaplan-Meier survival analysis showed no significant difference between CHD patients with and without 24-hour proteinuria (p=0.631).

CONCLUSION

CHD patients with proteinuria have significantly more thrombosis and more hypoxaemia than those patients without proteinuria.

Cyanotic nephropathy--a morphometric analysis

OBJECTIVE

Nephropathy is a known complication in cyanotic congenital heart disease (CCHD). This study was undertaken for an objective analysis of histopathological changes of cyanotic nephropathy at autopsy.

DESIGN

Retrospective case records studied.

SETTING

Tertiary care teaching hospital affiliated to medical college in Mumbai, India.

PATIENTS AND METHODS

The renal histopathological findings of 50 consecutive autopsies in patients with CCHD were compared with 25 age-matched controls. The Bowman's capsular, glomerular tuft, and hilar arteriolar diameters were measured morphometrically. Statistical analysis was performed using unpaired t-test. A P value equal to or less than .05 was considered significant.

RESULTS

Among the 50 autopsied cases of CCHD, there were 35 males and 15 females, with a mean age of 4.64 years. The renal changes observed were glomerulomegaly, glomerulosclerosis, periglomerular fibrosis, hyperplastic arteriolosclerosis, and interstitial fibrosis. The objectively measured parameters were higher in cases as compared with controls in all age groups, and further these were also found to be higher in patients having decreased pulmonary arterial blood flow than those having normal to increased pulmonary arterial blood flow. The difference in Bowman's capsular and glomerular tuft diameters was statistically significant in the neonates and children in the age groups, 1-5 years and above 10 years. The difference in hilar arteriolar diameter was statistically significant for all age groups except neonates.

CONCLUSION

Patients with CCHD show significant changes in the kidneys as assessed morphometrically, leading to renal dysfunction, and the age of the patients plays a role in their development.

Hypertrophic osteoarthropathy: what a rheumatologist should know about this uncommon condition

This article presents an updated overview of hypertrophic osteoarthropathy and digital clubbing for the practicing rheumatologist. Discussion includes a brief historical perspective, its definition, incidence and prevalence, classification, pathology and pathophysiology, clinical manifestations, demographics, findings on physical examination, imaging techniques for its detection, differential diagnosis, and treatment modalities.

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.

Congenital heart disease and pulmonary hypertension

Many patients with congenital heart disease and systemic-to-pulmonary shunts develop pulmonary arterial hypertension (PAH), particularly if the cardiac defect is left unrepaired. A persistent increase in pulmonary blood flow may lead to obstructive arteriopathy and increased pulmonary vascular resistance, a condition that can lead to reversal of shunt and cyanosis (Eisenmenger syndrome). Cardiac catheterization is crucial to confirm diagnosis and facilitate treatment. Bosentan is the only medication to date to be compared with placebo in a randomized controlled trial specifically targeting congenital heart disease-associated PAH. Lung transplantation with repair of the cardiac defect or combined heart-lung transplantation is reserved for recalcitrant cases.

Successful initiation and maintenance of hemodialysis in an adult patient with complete transposition of the great arteries

Cyanotic congenital heart disease (CCHD) is a life-threatening cardiac defect that requires palliative or corrective surgery in early life. Major advances in medical and surgical management have resulted in the survival of CCHD patients to adulthood with or without corrective surgery, though some are at risk of development of end-stage renal disease (ESRD) due to cyanotic nephropathy (CN). There is little or no information on the initiation and maintenance of hemodialysis (HD) in such patients. We present here a case of a 44-year-old man with complete transposition of the great arteries and CN-related ESRD. He had only received a bi-directional Glenn's operation and still suffered persistent severe hypoxemia and impaired cardiac function. ESRD was successfully treated with HD over more than 4 years. The case emphasizes the need for special attention in the selection and initiation of renal replacement therapy.

Renal function of patients with a failing Fontan circuit undergoing total cavopulmonary revision surgery

This report characterizes renal dysfunction after total cavopulmonary (TCPC) revision surgery for atriopulmonary Fontan (APF) circulations, a known risk factor for a poor outcome. The perioperative data for 23 consecutively identified patients were reviewed. The preoperative mean glomerular filtration rate (GFR) was 101 +/- 30 ml/min/1.73 m(2), decreasing to 65 +/- 41 ml/min/1.73 m(2) early in the postoperative period. The preoperative GFR was highly correlated with age at APF (r = -0.5; p = 0.024), age at TCPC (r = -0.5; p = 0.01), and mixed venous saturation (r = 0.6; p = 0.01). Three of four patients requiring renal replacement therapy (RRT) died at a median age of 3 months (range, 18 days to 9 months). Determinants of early GFR and RRT were preoperative GFR (p = 0.016) and creatinine (p = 0.035). Younger age at primary Fontan (p = 0.008), higher preoperative mixed venous saturation (p = 0.019), and higher preoperative blood pressure (p = 0.006) independently predicted better GFRs at the latest follow-up evaluation. Renal function declines acutely after TCPC revision, often necessitating RRT. A requirement for RRT marks greater mortality. Higher preoperative creatinine levels identify those at greatest risk.

Repeated phlebotomies improve and stabilise renal function in cyanotic nephropathy

Patients over 10 years of age with cyanotic congenital heart disease (CCHD) risk developing significant glomerular proteinuria, a condition called cyanotic nephropathy. Even though the pathogenesis of glomerulopathy associated with CCHD is still unclear, a potential mechanism is hyperviscosity-induced decrease in peritubular capillary blood flow leading to an increase in glomerular capillary pressure, in turn resulting in proteinuria. Although angiotensin-converting enzyme (ACE) inhibitors have been traditionally used in the treatment of these patients with cyanotic nephropathy, they may, however, not be well tolerated. Here we present a case of an adult patient with CCHD who could not tolerate an ACE inhibitor but showed improvement and stabilisation of her renal function following treatment with repeated phlebotomies.

The challenge of renal function in heart transplant children

Renal dysfunction may occur after pediatric heart transplantation and impacts on long-term prognosis. This study aims to review the incidence and mechanisms of chronic nephropathy following heart transplantation, and suggest therapeutic directions. The proportion of pediatric heart-transplant recipients with impaired renal function varies from 22 to 57%, and end-stage renal failure from 3 to 10%, depending on the method used for estimating the glomerular filtration rate. The pathophysiology of renal dysfunction is in part due to calcineurin inhibitor-induced renal vasoconstriction, through activation of the intrarenal renin-angiotensin system, TGF-beta1 upregulation and TGF-beta1 gene polymorphisms. Overproduction of angiotensin II, associated with angiotensin-converting-enzyme genotype, might be associated with poor prognosis and pharmacological factor gene polymorphisms, and may contribute to variation of calcineurine inhibitor exposure in the kidney. Strategies to prevent renal dysfunction include reducing calcineurine inhibitor exposure or delaying calcineurine inhibitor administration from the early post-transplant period. Calcium channel blockers and angiotensin-converting-enzyme inhibitors, blockade of angiotensin II, or anti-TGF-beta1 antibodies might limit nephrotoxicity. No accurate marker can predict the potential of renal lesions to develop. Lowering calcineurine inhibitors levels with immunosuppressive agents that are either less nephrotoxic or non-nephrotoxic should be formally studied. Of high interest is the impact of genetic polymorphism on the development of renal dysfunction.

Pulmonary Vascular Disease in Adults With Congenital Heart Disease

Pulmonary arterial hypertension of variable degree is commonly associated with adult congenital heart disease. Depending on size and location of the underlying cardiac defect as well as on repair status, pulmonary arterial hypertension may present with or without reversed shunting and associated cyanosis (ie, Eisenmenger syndrome). We review available data on etiology, clinical presentation, prognosis, and management strategies of pulmonary arterial hypertension in adult patients with congenital heart disease. In addition, we discuss the numerous complications associated with Eisenmenger syndrome, representing a multisystem disorder. Finally, we present general management strategies and emerging disease-targeting therapies.

Mechanisms of development and progression of cyanotic nephropathy

Cyanotic nephropathy (CN) is often accompanied by congenital cyanotic heart diseases (CCHD). The purpose of this study was to clarify the risk factors and the mechanisms of involved in the development and progression of CN. Thirty patients with CCHD were examined. We analyzed the risk factors for the development of CN on the basis of the clinical and laboratory findings. We also examined ten renal biopsy specimens obtained from patients with CN. Patients with CN showed significantly higher hematocrit levels than those without CN (P=0.025), although there was no difference between the two groups in terms of oxygen saturation. The renal plasma flow (RPF) in patients both with and without CN was low. However, the filtration fraction (FF) was significantly lower in patients with CN than in those without CN (P=0.001). The glomeruli of biopsy specimens with significant proteinuria (n=7) were larger than those of biopsy specimens without significant proteinuria, and there were more capillaries per glomerulus in the former than in the latter (n=3) and the control specimens (n=6) (glomerular size: P<0.01; number of glomerular capillaries: P<0.01). In conclusion, hyperviscosity by polycythemia may be responsible for the development of CN. This pathological condition may induce an angiogenic increase in the glomerular capillary beds, in turn leading to glomerulomegaly. In addition, the failure of a compensatory mechanism to respond to reduced RPF by hyperfiltration may be accompanied by the development and progression of CN.

Pathogenesis of thrombocytopenia in cyanotic congenital heart disease

Although a significant minority of patients with cyanotic congenital heart disease (CCHD) are thrombocytopenic, the pathogenesis and prevalence have not been established. This study was designed to address these 2 issues. We included 105 patients with CCHD (60 men and 45 women; aged 21 to 54 years). Systemic arterial oxygen saturations were 69% to 78%. Hematocrits were 62% to 74% with normal iron indexes. In 26 of 105 patients (25%), platelet counts were <100x10(9)/L. The diagnosis was Eisenmenger syndrome in all 26 patients with thrombocytopenia. Platelet production was determined by flow cytometric reticulated platelet counts. Megakaryocyte mass was determined indirectly by thrombopoietin levels. Disseminated intravascular coagulation was based on prothrombin time, activated partial thromboplastin time, and D-dimers. Platelet activation was determined by levels of platelet factor 4 and beta thromboglobulin. Reference ranges were derived from 20 normal acyanotic controls. A reduction in absolute reticulated platelet counts implied decreased platelet production (p<0.001). Normal thrombopoietin levels implied normal megakaryocyte mass. Normal prothrombin time, activated partial thromboplastin time, and D-dimers excluded disseminated intravascular coagulation. Normal platelet factor 4 and beta thromboglobulin indicated absent or minimal platelet activation. Twenty-five percent of the patients with CCHD were thrombocytopenic because platelet production was decreased despite normal megakaryocyte mass. We hypothesized that right-to-left shunts deliver whole megakaryocytes into the system arterial circulation, bypassing the lungs where megakaryocytic cytoplasm is fragmented into platelets, thus reducing platelet production. In conclusion, platelet counts in CCHD appear to represent a continuum beginning with low normal counts and ending with thrombocytopenia.