Invasive and noninvasive hemodynamic assessment in adults with Fontan palliation

Improvement in hepatic and renal function following isolated heart transplant in adults with congenital heart disease

BACKGROUND

There are limited data about postoperative changes in hepatic and renal function in adults with congenital heart disease (CHD) undergoing isolated heart transplant. The purpose of this study was to assess postoperative changes in hepatic and renal function in this population.

METHODS

Retrospective cohort study of adults with CHD undergoing isolated heart transplant at Mayo Clinic (2003-2019). Global hepatic function was assessed using the model for end-stage liver disease excluding international normalized ratio [MELD-XI]) score; hepatic fibrosis was assessed using the fibrosis-4 (FIB-4) score and aspartate/platelet ratio index (APRI); and renal function was assessed using estimated glomerular filtration rate (GFR). All indices were measured preoperatively and postoperatively (at 6 months, 1 year, 2 years).

RESULTS

Of 40 patients (age 41 ± 8 years) in the study, 35 had complete preoperative and postoperative data. There was a temporal improvement in hepatic and renal indices from preop (MELD-XI 14 ± 5, APRI 0.60 ± 0.23, FIB-4 1.44 ± 0.38, GFR 59 [44-83]) to 6 months postop (MELD-XI 12 ± 6, APRI 0.49 ± 0.17, FIB-4 1.29 ± 0.33, GFR 68 [54-96]) and 1-year postop (MELD-XI 9 ± 3, APRI 0.41 ± 0.16, FIB-4 1.12 ± 0.29, GFR 82 [69-108]), p < 0.05 for all comparisons.

CONCLUSIONS

CHD patients undergoing isolated heart transplant had significant improvement in hepatic and renal function. These data suggests that selected CHD patients may do well with isolated heart transplant despite reduced hepatic and renal function, and hepatic fibrosis preoperatively. More rigorous prospective studies are required to determine the relative outcomes of isolated versus combined heart-liver transplant in this population.

Late Fontan Circulatory Failure. What Drives Systemic Venous Congestion and Low Cardiac Output in Adult Fontan Patients?

The Fontan circulation provides definite palliation for children born with a single anatomical or functional ventricle by diverting systemic venous blood directly to the pulmonary arteries, effectively rendering systemic venous return into portal vessels to the lung. Although this restores pulmonary blood flow and avoids the mixture of oxygenated and deoxygenated blood, it also results in elevated systemic venous pressures and low cardiac output. These are the two hallmarks of any Fontan circulation and the cause of Fontan circulatory failure later in life. We highlight the determinants of systemic venous return, its changed relationship with the pulmonary circulation, how it affects preload, and the changed role of the heart (myocardium, valves, and heart rate). By critically evaluating the components of the Fontan circulation, we hope to give some clues in how to optimize the Fontan circulation and avenues for future research.

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.

Heart Failure in Adult Congenital Heart Disease

As the population of adult congenital heart disease patients ages and grows, so too does the burden of heart failure in this population. Despite the advances in medical and surgical therapies over the last decades, heart failure in adult congenital heart disease remains a formidable complication with high morbidity and mortality. This review focuses on the challenges in determining the true burden and management of heart failure in adult congenital heart disease. There is a particular focus on the need for developing a common language for classifying and reporting heart failure in adult congenital heart disease, the clinical presentation and prognostication of heart failure in adult congenital heart disease, the application of hemodynamic evaluation, and advanced heart failure treatment. A common case study of heart failure in adult congenital heart disease is utilized to illustrate these key concepts.

Feasibility, reproducibility and accuracy of electrical velocimetry for cardiac output assessment in congenital heart disease

BACKGROUND

Noninvasive cardiac output assessment is important for prognostication in patients with heart failure. Electrical velocimetry (EV), an impedance cardiography technique, can be used for noninvasive cardiac output assessment. The purpose of this study was to determine the feasibility, reproducibility and accuracy of cardiac output assessment by EV in adults with congenital heart disease (CHD).

METHODS

Cross-sectional study of CHD patients that had simultaneous cardiac output assessment by Fick and EV (using Cardiotronic monitor, Osypka Medical). We divided the cohort into: Group 1 patients (n = 54) had hemodynamic assessment at rest only, while Group 2 patients (n = 7) had assessment both at rest and peak exercise.

RESULTS

EV cardiac output assessment was feasible in 100% of the patients. There was good correlation between Fick-derived and EV-derived cardiac index (r = 0.89, p < 0.001) in Group 1. Among 26 patients in Group 1 that underwent cardiac output assessment pre- and post-intervention, there was no difference in the strength of correlation of Fick and EV cardiac output pre- and post-intervention (p-interaction 0.244) indicating good reproducibility of the technique. There was also modest correlation between Fick-derived and EV-derived cardiac index at rest (r = 0.68, p = 0.032), and peak exercise (r = 0.62, p = 0.055), in Group 2.

CONCLUSION

In this study, we demonstrated the feasibility and accuracy of EV cardiac output assessment in adults with CHD. We also demonstrated, for the first time, that EV cardiac output assessment was reproducible under different loading conditions, and that EV can be used for the assessment of cardiac output augmentation at peak exercise.