Effect of Ambrisentan on Exercise Capacity in Adult Patients After the Fontan Procedure

Morbidity and mortality in adults with a Fontan circulation beyond the fourth decade of life

AIMS

To evaluate the late outcomes of adults (above 35 years) with a Fontan-type circulation, for whom current data on morbidity and mortality are lacking.

METHODS AND RESULTS

Data were collected retrospectively on consecutive patients with Fontan circulation above the age of 35 years followed in three European specialist centres. Overall, 115 Fontan patients were included [median age 35 (range 35-48) years, 47.8% female]. The most common underlying congenital heart disease diagnosis was tricuspid atresia (n = 58, 50.4%), and the age at first Fontan completion was 9.1 (interquartile range 5.0-15.8) years. Almost two-thirds (61.7%) of patients had undergone an atriopulmonary Fontan, and 23.5% had received a total cavopulmonary connection. One-third required repeat surgery or intervention. Most patients (55.9%) were in New York Heart Association functional class II or class I (30.6%), 76 (66.1%) patients had experienced at least one arrhythmia, and eight (7.0%) protein-losing enteropathy. At a median follow-up of 5.0 (2.4-10.3) years, 15 (13.0%) patients were referred for transplantation assessment and 19 (16.5%) patients died, mainly from heart failure (84.2%). Univariable predictors of death or transplantation included lower serum albumin level [hazard ratio (HR) 1.09 per g/L decrease, 95% confidence interval (CI): 1.04-1.15, P = 0.0009], prior heart failure admission (HR 4.28, 95% CI:1.75-10.44, P = 0.001), prior atrial tachycardia or flutter (HR 3.02, 95% CI: 1.23-7.38, P = 0.02), and baseline pulmonary vasodilator therapy (HR 8.59, 95% CI:1.05-70.13, P = 0.04). Lower serum albumin and prior atrial tachycardia or flutter remained significant on bivariable analysis.

CONCLUSION

Our study highlights the significant morbidity and mortality in older adults with a Fontan-type circulation, emphasizing the need for lifelong specialist surveillance with frequent risk stratification, close monitoring, and early consideration for transplantation assessment.

Pulmonary vasodilators and exercise in Fontan circulation: a systematic review and meta-analysis

OBJECTIVE

In Fontan circulation, pulmonary arterial hypertension (PAH)-targeted therapies could improve the patients' exercise capacity. This study aimed to investigate the effects of PAH agents on different exercise parameters in stable Fontan patients by synthesising evidence of randomised controlled trials (RCTs).

METHODS

A systematic search of PubMed, Cochrane Central Register of Controlled Trials and Web of Science databases, as well as of ClinicalTrials.gov, was performed. Primary outcomes were specific cardiopulmonary exercise test parameters: peak oxygen uptake (peak VO2), peak heart rate (peak HR), the minute ventilation/produced carbon dioxide (VE/VCO2) slope and the oxygen uptake, both measured at the anaerobic threshold (VO2@AT).

RESULTS

Five RCTs were included in the analysis including 573 Fontan patients (mean age 21.2 years, 60% male). PAH-targeted therapies did not affect peak VO2 (mean difference (MD) 0.72, 95% CI -0.25 to 1.70) or peak HR (MD -0.67, 95% CI -3.81 to 2.47), but resulted in a small, significant improvement in VO2@AT (standardised MD 0.24, 95% CI 0.02 to 0.47). VE/VCO2 slope at the anaerobic threshold was also reduced (MD -1.13, 95% CI -2.25 to -0.01).

CONCLUSIONS

Although PAH-targeted therapies did not affect exercise parameters at maximal effort, they induced slight improvements in indices of submaximal effort, measured at the anaerobic threshold. Pharmacological improvement of submaximal exercise seems to be a more suitable indicator of Fontan individuals' exercise capacity. Larger RCTs, recruiting specific subpopulations and focusing also on the anaerobic threshold, are warranted to draw more robust conclusions.

PROSPERO REGISTRATION NUMBER

CRD42022306674.

Novel Therapeutic Strategies in Heart Failure in Adult Congenital Heart Disease: of Medicines and Devices

PURPOSE OF REVIEW

This paper reviews the latest literature on the growing field of heart failure in the adult congenital heart disease population.

RECENT FINDINGS

After highlighting the increasing prevalence and a few of the unique potential causes, including the concept of early senescence, this review begins with novel medical management strategies such as the angiotensin II receptor blocker and neprilysin inhibitors and sodium glucose cotransporter-2 inhibitors. Then, it addresses the latest applications of percutaneous techniques like implantable hemodynamic monitoring, transcatheter pulmonary and aortic valve replacement, and mitral clips. Cardiac resynchronization therapy and novel lymphatic system imaging and intervention are then described. Finally, the use of mechanical support devices, temporary and durable, is discussed as well as heart and combined heart and liver transplantation. There have been recent exciting advances in the strategies used to manage adult congenital heart disease patients with heart failure. As this population continues to grow, it is likely we will see further rapid evolution in this field.

Unique Pulmonary Hypertensive Vascular Diseases Associated with Heart and Lung Developmental Defects

Although pediatric pulmonary hypertension (PH) shares features and mechanisms with adult PH, there are also some significant differences between the two conditions. Segmental PH is a unique pediatric subtype of PH with unclear and/or multifactorial pathophysiological mechanisms, and is often associated with complex congenital heart disease (CHD), pulmonary atresia with ventricular septal defect, and aortopulmonary collateral arteries. Some cases of complex CHD, associated with a single ventricle after Fontan operation, show pathological changes in the small peripheral pulmonary arteries and pulmonary vascular resistance similar to those observed in pulmonary arterial hypertension (PAH). This condition is termed as the pediatric pulmonary hypertensive vascular disease (PPHVD). Recent advances in genetics have identified the genes responsible for PAH associated with developmental defects of the heart and lungs, such as TBX4 and SOX17. Targeted therapies for PAH have been developed; however, their effects on PH associated with developmental heart and lung defects remain to be established. Real-world data analyses on the anatomy, pathophysiology, genetics, and molecular biology of unique PPHVD cases associated with developmental defects of the heart and lungs, using nationwide and/or international registries, should be conducted in order to improve the treatments and prognosis of patients with these types of pediatric PH.

Cardiac Drugs in ACHD Cardiovascular Medicine

Adult congenital heart disease (ACHD) is a growing population that requires life-long care due to advances in pediatric care and surgical or catheter procedures. Despite this, drug therapy in ACHD remains largely empiric due to the lack of clinical data, and formalized guidelines on drug therapy are currently lacking. The aging ACHD population has led to an increase in late cardiovascular complications such as heart failure, arrhythmias, and pulmonary hypertension. Pharmacotherapy, with few exceptions, in ACHD is largely supportive, whereas significant structural abnormalities usually require interventional, surgical, or percutaneous treatment. Recent advances in ACHD have prolonged survival for these patients, but further research is needed to determine the most effective treatment options for these patients. A better understanding of the use of cardiac drugs in ACHD patients could lead to improved treatment outcomes and a better quality of life for these patients. This review aims to provide an overview of the current status of cardiac drugs in ACHD cardiovascular medicine, including the rationale, limited current evidence, and knowledge gaps in this growing area.

Subcutaneous Treprostinil Improves Surgical Candidacy for Next Stage Palliation in Single Ventricle Patients With High-Risk Hemodynamics

Single ventricle (SV) patients with pulmonary vascular disease (SV-PVD) are considered poor surgical candidates for Glenn or Fontan palliation. Given limited options for Stage 1 (S1) and Stage 2 (S2) SV patients with SV-PVD, we report on the use of subcutaneous treprostinil (TRE) to treat SV-PVD in this population. This single-center, retrospective cohort study examined SV patients who were not candidates for subsequent surgical palliation due to SV-PVD and were treated with TRE. The primary outcome was ability to progress to the next surgical stage; secondary outcomes included changes in hemodynamics after TRE initiation. Between 3/2014 and 8/2021, 17 SV patients received TRE for SV-PVD: 11 after S1 and 6 after S2 (median PVR 4.1 [IQR 3.2-4.8] WU*m2 and 5.0 [IQR 1.5-6.1] WU*m2, respectively). Nine of 11 (82%) S1 progressed to S2, and 2 (18%) underwent heart transplant (HTx). Three of 6 (50%) S2 progressed to Fontan, 1 underwent HTx and 2 are awaiting Fontan on TRE. TRE significantly decreased PVR in S1 patients with median post-treatment PVR of 2.0 (IQR 1.5-2.6) WU*m2. TRE can allow for further surgical palliation in select pre-Fontan patients with SV-PVD, obviating the need for HTx. Improvement in PVR was significant in S1 patients and persisted beyond discontinuation of therapy for most patients.

Hypoplastic Left Heart Syndrome Across the Lifespan: Clinical Considerations for Care of the Fetus, Child, and Adult

Hypoplastic left heart syndrome (HLHS) is the most common anatomic lesion in children born with single ventricle physiology and is characterized by the presence of a dominant right ventricle and a hypoplastic left ventricle along with small left-sided heart structures. Diagnostic subgroups of HLHS reflect the extent of inflow and outflow obstruction at the aortic and mitral valves, specifically stenosis or atresia. If left unpalliated, HLHS is a uniformly fatal lesion in infancy. Following introduction of the Norwood operation, early survival has steadily improved over the past four decades, mirroring advances in operative and peri-operative management as well as reflecting refinements in patient surveillance and interstage clinical care. Notably, survival following staged palliation has increased from 0% to a 5-year survival of 60-65% for children in some centres. Despite the prevalence of HLHS in childhood with relatively favourable surgical outcomes in contemporary series, this cohort is only now reaching early adult life and longer-term outcomes have yet to be elucidated. In this article we focus on contemporary clinical management strategies for patients with HLHS across the lifespan, from fetal to adult life. Nomenclature and diagnostic considerations are discussed and current literature pertaining to putative genetic etiologies is reviewed. The spectrum of fetal and pediatric interventional strategies, both percutaneous and surgical, are described. Clinical, patient-reported and neurodevelopmental outcomes of HLHS are delineated. Finally, note is made of current areas of clinical uncertainty and suggested directions for future research are highlighted.

Increased Circulating Endothelin 1 Is Associated With Postoperative Hypoxemia in Infants With Single-Ventricle Heart Disease Undergoing Superior Cavopulmonary Anastomosis

Background Inadequate pulmonary vascular growth results in morbidity for many children with single-ventricle heart disease (SVHD). Endothelin 1 (ET1) is a potent vasoconstrictor and stimulator of pulmonary artery smooth muscle proliferation. Circulating ET1 levels and their association with outcomes have not been studied during early SVHD palliation. We aimed to define circulating levels of ET1 in patients with SVHD undergoing stage 2 palliation and evaluate their relationship to postoperative hypoxemia. We hypothesized that patients with SVHD with higher ET1 concentration would have a greater post-stage 2 hypoxemia. Methods and Results Prospective cohort study of 55 subjects with SVHD undergoing stage 2 palliation and 50 controls. Samples for ET1 analysis were collected at preoperation (systemic and pulmonary vein) and 2, 24, and 48 hours postoperation for cases and a single time point for controls. The primary outcome was percentage of first 48 postoperative hours with clinically significant hypoxemia (saturation, <70%). ET1 concentration was lower in preoperative cases than controls (2.2 versus 2.7 pg/mL; P=0.0015) and in the pulmonary vein than systemic vein (1.7 versus 2.2 pg/mL; P<0.001). ET1 level increased by 2 hours postoperation and trended back to baseline by 48 hours. Higher preoperative pulmonary vein ET1 and 2 hours postoperative ET1 were associated with larger hypoxemia burden (10.6% versus 2.7% [P=0.0081]; and 7.6% versus 3.2% [P=0.01], respectively). Multivariable testing demonstrated ET1 concentration and cardiopulmonary bypass time were associated with hypoxemia, whereas catheterization measurements and clinical variables were not. Conclusions Infants with SVHD with higher perioperative ET1 concentration experience more post-stage 2 hypoxemia. ET1 activity may be a modifiable risk factor of pulmonary vascular inadequacy for stage 2 palliation.

Pharmacology Management in Improving Exercise Capacity of Patients with Fontan Circulation: A Systematic Review and Meta-analysis

BACKGROUND

The Fontan procedure is currently the mainstay therapy for single functional ventricles. However, with prolonged follow-up duration, various complications have been observed that seriously influence the quality of life of patients.

OBJECTIVES

The aim of this meta-analysis is to compare the effectiveness of pharmacologic agents in improving exercise capacity in patients with Fontan circulation.

METHODS

This meta-analysis was conducted according to the Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) statement and has been registered in the International Prospective Register for Systematic Reviews database with registration no. 282352. Quality assessments of the included studies were assessed using the Strengthening Reporting of Observational Studies in Epidemiology (STROBE) statement.

RESULTS

Twelve studies met the predetermined inclusion criteria and were included in this metaanalysis. This meta-analysis found that treatment with bosentan significantly improved New York Heart Association Functional Class (NYHA FC) in Fontan patients (standard mean difference - 0.59, 95% CI -0.94 - -0.25; P=0.0008; I2 = 1%). However, the use of bosentan (P=0.66) and sildenafil (P=0.13) did not show a significant improvement in the maximum rate of oxygen consumption (VO2 max).

CONCLUSION

This meta-analysis shows that people with Fontan circulation may benefit from using bosentan as it decreases postexercise heart rate and improves NYHA FC and 6-minute walking test results. Therefore, indirectly improving exercise capacity. Nonetheless, considerable work is required to strengthen our knowledge in improving the exercise capacity of Fontan patients.

Use of Pulmonary Arterial Hypertension Therapies in Patients with a Fontan Circulation: Current Practice Across the United Kingdom

Background

The Fontan circulation is a successful operative strategy for abolishing cyanosis and chronic volume overload in patients with congenital heart disease with single ventricle physiology. “Fontan failure” is a major cause of poor quality of life and mortality in these patients. We assessed the number and clinical characteristics of adult patients with Fontan physiology receiving pulmonary arterial hypertension (PAH) therapies across specialist centers in the United Kingdom.

Methods and Results

We identified all adult patients with a Fontan‐type circulation under active follow‐up in 10 specialist congenital heart disease centers in England and Scotland between 2009 and 2019. Patients taking PAH therapies were matched to untreated patients. A survey of experts was also performed. Of 1538 patients with Fontan followed in specialist centers, only 76 (4.9%) received PAH therapies during follow‐up. The vast majority (90.8%) were treated with a phosphodiesterase‐5 inhibitor. In 33% of patients, PAH therapies were started after surgery or during hospital admission. In the matched cohort, treated patients were more likely to be significantly limited, have ascites, have a history of protein‐losing enteropathy, or receive loop diuretics (P<0.0001 for all), also reflecting survey responses indicating that failing Fontan is an important treatment target. After a median of 12 months (11–15 months), functional class was more likely to improve in the treated group (P=0.01), with no other changes in clinical parameters or safety issues.

Conclusions

PAH therapies are used in adult patients with Fontan circulation followed in specialist centers, targeting individuals with advanced disease or complications. Follow‐up suggests stabilization of the clinical status after 12 months of therapy.

Pulmonary vascular disease in Fontan circulation-is there a rationale for pulmonary vasodilator therapies?

The Fontan circulation is a palliative concept for patients with univentricular hearts. The central veins are connected directly to the pulmonary arteries (cavo-pulmonary connection) to separate the pulmonary and the systemic circulation. There is no sub-pulmonary ventricle that generates pressure to drive blood through the pulmonary arteries. Pulmonary blood flow is determined by central venous pressure (CVP) and pulmonary vascular resistance (PVR). The capability of the Fontan circulation to compensate for alterations in PVR is limited, as CVP can only be increased within narrow ranges without adverse clinical consequences. Consequently, systemic ventricular preload and cardiac output are dependent on a healthy lung with low PVR. Failure of the Fontan circulation is relatively common. In addition to ventricular dysfunction, maladaptive pulmonary vascular remodeling resulting in increased pulmonary resistance may play a key role. The pathophysiology of the maladaptive vascular processes remains largely unclear and diagnosis of an increased PVR is challenging in Fontan circulation as accurate measurement of pulmonary arterial blood flow is difficult. In the absence of a sub-pulmonary ventricle, pulmonary artery pressure will almost never reach the threshold conventionally used to define pulmonary arterial hypertension. There is a need for markers of pulmonary vascular disease complementary to invasive hemodynamic data in Fontan patients. In order to treat or prevent failure of the Fontan circulation, pathophysiological considerations support the use of pulmonary vasodilators to augment pulmonary blood flow and systemic ventricular preload and lower CVP. However, to date the available trial data have neither yielded enough evidence to support routine use of pulmonary vasodilators in every Fontan patient nor have they been helpful in defining subgroups of patients that might benefit from such therapies. This review discusses potential pathomechanisms of pulmonary vascular disease; it summarizes the current knowledge of the effects and efficacy of pulmonary vasodilator therapy in Fontan patients and tries to outline areas of potential future research on the diagnosis and treatment of pulmonary vascular disease and Fontan failure.

Evidence base for specific pulmonary vasodilators in adults with congenital heart disease

After reviewing the current definitions and classification of pulmonary hypertension (PH) associated with congenital heart disease (CHD), based on an analysis of 59 clinical trials (of which 14 are randomized controlled trials) drugs registered in the Russian Federation, the evidence base for PH therapy in adults with CHD is provided. The presence of a randomized controlled trial of bosentan BREATHE-5 and uncontrolled trials of other drugs became the basis for a higher class and level of evidence of bosentan (IB) compared to other drugs (IIaC) for Eisenmenger syndrome in the current European (ERS/ESC 2015) and updated Russian (2020) guidelines. According to the updated European (ESC 2020) guidelines for congenital heart disease in adults, in Eisenmenger patients with reduced exercise capacity (6MWT distance 450 m), a treatment strategy with initial endothelin receptor antagonist monotherapy should be considered followed by combination therapy if patients fail to improve (IIaB), in low- and intermediate-risk patients with repaired simple lesions and pre-capillary PH, initial oral combination therapy or sequential combination therapy is recommended and high-risk patients should be treated with initial combination therapy including parenteral prostanoids (IA) and endothelin receptor antagonists and phosphodiesterase 5 inhibitors may be considered in selected patients with elevated pulmonary pressure/resistance in the absence of elevated ventricular end diastolic pressure (IIbC). Only three (bosentan, macitentan and selexipag) out of seven specific pulmonary vasodilators registered in the Russian Federation have indications for pulmonary arterial hypertension associated with congenital heart disease and Eisenmenger syndrome or pulmonary arterial hypertension associated with corrected simple congenital heart disease in the instructions for use.

The pulmonary vascular bed in patients with functionally univentricular physiology and a Fontan circulation

Fontan palliation represents one of the most remarkable surgical advances in the management of individuals born with functionally univentricular physiology. The operation secures adult survival for all but a few with unfavourable anatomy and/or physiology. Inherent to the physiology is passive transpulmonary blood flow, which produces a vulnerability to adequate filling of the systemic ventricle at rest and during exertion. Similarly, the upstream effects of passive flow in the lungs are venous congestion and venous hypertension, especially marked during physical activity. The pulmonary vascular bed has emerged as a defining character on the stage of Fontan circulatory behaviour and clinical outcomes. Its pharmacologic regulation and anatomic rehabilitation therefore seem important strategic therapeutic targets. This review seeks to delineate the important aspects of pulmonary artery development and maturation in functionally univentricular physiology patients, pulmonary artery biology, pulmonary vascular reserve with exercise, and pulmonary artery morphologic and pharmacologic rehabilitation.

Pulmonary vasodilator therapy after the Fontan procedure: a meta-analysis

We aimed to assess the efficacy and safety of pulmonary vasodilators in patients after the Fontan procedure. The PubMed, EMBASE, and Cochrane Library databases were searched through November 2019 for studies comparing pulmonary vasodilators and controls in Fontan patients. The variables assessed included change in pulmonary resistance, heart function, exercise capacity, quality of life, mortality, and adverse events after drug administration. A random/fixed effects model was used to assess the mean difference (MD)/risk ratio (RR) with 95% confidence intervals (CIs). Subgroup analysis was stratified by drug category. In total, 449 Fontan patients from 13 studies were included. Pooled estimates of the change in pulmonary arterial pressure (MD, - 1.07; 95% CI, - 2.75 to 0.60; p = 0.21), New York Heart Association class (MD, - 0.57; 95% CI, - 1.41 to 0.28; p = 0.19), peak oxygen consumption (MD, 1.46; 95% CI, 0.01 to 2.90; p = 0.05), Short Form 36 (MD, 1.39; 95% CI, - 0.62 to 3.39; p = 0.17), mortality (RR, 0.37; 95% CI, 0.08 to 1.65; p = 0.19), and any adverse event (RR, 0.94; 95% CI, 0.71 to 1.24; p = 0.64) were not significantly different between the drug and control groups. Likewise, most results of the subgroup analysis revealed no significant between-group differences. Pulmonary vasodilator therapy appears to be safe, but not beneficial, in the categories of pulmonary resistance, heart function, or quality of life in patients who have undergone a Fontan procedure. No significant evidence was found to confirm that most pulmonary vasodilators could improve exercise capacity in Fontan patients.

The efficacy and safety of pulmonary vasodilators in patients with Fontan circulation: a meta-analysis of randomized controlled trials

No previous meta-analysis has evaluated the efficacy and safety of pulmonary vasodilators in Fontan physiology. Recent relative trials have obtained conflicting results regarding improvements in peak oxygen consumption; the relatively small number of patients in each study may be a limiting factor. We aimed to evaluate the efficacy and safety of pulmonary vasodilators in Fontan patients. Relevant studies were identified by searching the PubMed, Embase, and Cochrane Library databases. Pooled outcomes were determined to assess the efficacy and safety of pulmonary vasodilators in Fontan patients. Nine randomized controlled studies involving 381 patients with Fontan circulation were included. Pulmonary vasodilator therapy led to significant improvement (mean difference = -0.39, 95% CI: [-0.72, -0.05]) in the New York Heart Association (NYHA) functional class. The 6-minute walking distance (6MWD) was significantly increased by 134 m (95% CI: [86.07, 181.94]), and the peak VO2 was also significantly improved (mean difference = 1.42 ml·(kg·min)-1, 95% CI: [0.21, 2.63]). Additionally, the mean pulmonary artery pressure (mPAP) was significantly reduced (mean difference = -2.25 mmHg, 95% CI: [-3.00, -1.50]). No significant change was found in mortality or in brain natriuretic peptide (BNP) or N-terminal pronatriuretic peptide (NT-proBNP). Four studies reported no side effects and good drug tolerance, and two studies reported mild adverse effects. The present meta-analysis indicated that pulmonary vasodilators (primarily the PDE-5 inhibitor and endothelin-1 receptor antagonist) significantly improved the hemodynamics of Fontan patients, reduced the NYHA functional class and increased the 6MWD. The peak oxygen consumption was also improved. No significant change was observed in mortality or in the BNP or NT-proBNP level. Overall, the pulmonary vasodilators were well tolerated. This finding needs to be confirmed in future studies.

Long Term Consequences of the Fontan Procedure and How to Manage Them

In 1971, Fontan and Baudet described a surgical technique for successful palliation of patients with tricuspid atresia. Subsequently, this technique has been applied to treat most forms of functional single ventricles and has become the current standard of care for long-term palliation of all patients with single ventricle congenital heart disease. Since 1971, the Fontan procedure has undergone several variations. These patients require lifelong management including a thorough knowledge of their anatomic substrate, hemodynamic status, management of rhythm and ventricular function along with multi organ evaluation. As these patients enter middle age, there is increasing awareness regarding the long-term complications and mortality. This review highlights the long-term outcomes of the Fontan procedure and management of late sequelae.

Pulmonary hypertension in adults with congenital heart disease: Updated recommendations from the Cologne Consensus Conference 2018

In the summer of 2016, delegates from the German Respiratory Society (DGP), the German Society of Cardiology (DGK) and the German Society of Pediatric Cardiology (DGPK) met in Cologne, Germany, to define consensus-based practice recommendations for the management of patients with pulmonary hypertension (PH). These recommendations were built on the 2015 European Pulmonary Hypertension guidelines, aiming at their practical implementation, considering country-specific issues, and including new evidence, where available. To this end, a number of working groups was initiated, one of which was specifically dedicated to PH in adults associated with congenital heart disease (CHD). As such patients are often complex and require special attention, and the general PAH treatment algorithm in the ESC/ERS guidelines appears too unspecific for CHD, the working group proposes an analogous algorithm for the management of PH-CHD which takes the special features of this patient group into consideration, and includes general measures, supportive therapy, targeted PAH drug therapy as well as interventional and surgical procedures. The detailed results and recommendations of the working group on PH in adults with CHD, which were last updated in the spring of 2018, are summarized in this article.

Effects of eplerenone on markers of myocardial fibrosis, 6-minute walk distance, and quality of life in adults with tetralogy of Fallot and complete transposition of the great arteries

Ventricular dysfunction is common among patients with repaired cyanotic congenital heart disease. To date, no pharmacologic intervention has been demonstrated to be beneficial in this setting. To begin addressing this knowledge gap, we conducted a single-center prospective, randomized, open-label pilot study to investigate the effects of eplerenone on serologic markers of collagen turnover and inflammation, 6-minute walk distance, and quality of life in patients with tetralogy of Fallot (TOF) or transposition of the great arteries with a systemic right ventricle (transposition of the great arteries [TGA]). Patients were randomized to a 3-month drug-free period at the beginning of the treatment period or at the end. All patients received 12 months of eplerenone therapy during the treatment period. Twenty-six patients were enrolled in the trial; 17 completed the study protocol: 8 with TOF and 9 with TGV. Eplerenone had no effect on serum levels of procollagen 1 N-terminal peptide (PINP), procollagen 3 N-terminal peptide (PIIINP), or galectin-3 (G3). Similarly, eplerenone had no effect on 6-minute walk distance or quality of life. In conclusion, PINP and PIIINP levels are as high as or higher in patients with TOF and TGA than in patients with normal cardiac anatomy and heart failure, whereas G3 levels are lower. Eplerenone is well tolerated by adults born with congenital heart disease.

Model-Based Comparison of the Normal and Fontan Circulatory Systems-Part III

BACKGROUND

For patients with the Fontan circulatory arrangement, angiotensin-converting enzyme inhibition, guanylate cyclase activation, phosphodiesterase 5 inhibition, and endothelin receptor antagonism have so far resulted in little or no improvement in [Formula: see text] or peak cardiac index (CI), suggesting that our understanding of the factors that most impact the exercise hemodynamics is incomplete.

METHODS

To facilitate comparisons with clinical reports of the exercise performance of preadolescent Fontan patients, we rescaled our previously reported computational models of a two-year-old normal child and similarly aged Fontan patient, extended our Fontan model to capture the nonlinear relationship between flow and resistance quantified from previous computational fluid dynamic analyses of the total cavopulmonary connection (TCPC), and added respiration as well as skeletal muscle contraction.

RESULTS

(1) Without respiration, the computational model for both the normal and the Fontan cannot attain the values for CI at peak exercise reported in the clinical literature, (2) because flow through the TCPC is much greater during inspiration than during expiration, the effect on the CI of the dynamic (flow-related) TCPC resistance is much more dramatic during exercise than it is in breath-hold mode at rest, and (3) coupling breathing with skeletal muscle contraction leads to the highest augmentation of cardiac output, that is, the skeletal muscle pump is most effective when the intrathoracic pressure is at a minimum-at peak inspiration.

CONCLUSIONS

Novel insights emerge when a Fontan model incorporating dynamic TCPC resistance, full respiration, and skeletal muscle contraction can be compared to the model of the normal.

Managing adult Fontan patients: where do we stand?

The Fontan operation is performed as a palliative procedure to improve survival in infants born with a functionally univentricular circulation. The success of the operation is demonstrated by a growing adult Fontan population that exists with this unique physiology. Late follow-up has demonstrated expected and unexpected sequelae, and has shown multisystem effects of this circulation. This review discusses the challenges of managing the late complications in terms of understanding this unique physiology and the innovative therapeutic interventions that are being investigated. The challenge remains to maintain quality of life for adult survivors, as well as extending life expectancy.

Innovative solutions are required to meet the challenges of the Fontan circulation faced in adult lifehttp://ow.ly/XTSm305oH8b