Filling pressures in Fontan revisited: Comparison between pulmonary artery wedge, ventricular end-diastolic, and left atrial pressures in adults

Exercise-induced changes in pulmonary artery wedge pressure in adults post-Fontan versus heart failure with preserved ejection fraction and non-cardiac dyspnoea

AIMS

Despite their universal predisposition, diagnosing diastolic dysfunction in patients post-Fontan palliation is challenging. Our aim was to compare exercise haemodynamics between adults post-Fontan and patients with heart failure with preserved ejection fraction (HFpEF) and non-cardiac dyspnoea (NCD).

METHODS AND RESULTS

Twenty-four adults (age ≥18 years) post-Fontan palliation with resting and exercise pulmonary artery wedge pressure (PAWP) measured during supine biking were identified. Forty-eight patients with HFpEF and 48 with NCD diagnosed at catheterization were selected for comparison. Mean age for Fontan patients was 30.3 ± 7.5 years; median ventricular ejection fraction was 52.5% (45-55.8), being <50% in 37.5%. Resting PAWP among Fontan patients was 10.2 ± 3.5 mmHg (>12 mmHg in 25%); PAWP was lower in Fontan patients than in HFpEF but higher than NCD. During exercise, PAWP was lower in the Fontan group than HFpEF (22.5 mmHg [19.3-28] vs. 28.2 ± 6.3; p = 0.0006) but higher than NCD (11.2 ± 4.2, p ≤ 0.0001). However, there were no differences in ΔPAWP/ΔQs between Fontan and HFpEF patients (4.0 [2.1-7.3] vs. 2.7 [1.6-4.4]; p = 0.10) with the ratio being higher post-Fontan than in NCD (0.6 [0.2-1.2]; p < 0.0001). ΔPAWP/ΔQs remained similar between HFpEF and Fontan patients even when those with ejection fraction <50% were excluded (2.7 [1.6-4.4] vs. 2.7 [1.0-5.8]; p = 0.97).

CONCLUSION

There were no differences in ΔPAWP/ΔQs ratios between post-Fontan and HFpEF patients, supporting markedly abnormal single ventricle compliance despite lower resting and exercise PAWP. Therefore, exercise invasive haemodynamics may represent a novel tool for the diagnosis of diastolic dysfunction in Fontan patients.

Heart transplantation for patients with single ventricle physiology

Background

There is a growing population of palliated and unpalliated single ventricle physiology patients for whom heart transplantation is the only treatment option available. There is a paucity of reports of heart transplantation in this challenging and growing subset of patients from our part of the world. The purpose of the article is to briefly review our experience in the subgroup and compare it with the available literature.

Methods

This was a single-institution retrospective observational study of 16 patients with single ventricle physiology who were transplanted between 2016 and 2019 and their outcomes. The study groups were divided into those with ventricular dysfunction (group 1), who fare substantially better than those with normal ventricular function (group 2) whose short-term outcomes were poorer. Worsening cyanosis, poor candidature for completion Fontan procedure due to severe atrioventricular valve regurgitation or pulmonary artery anatomy, protein-losing enteropathy, plastic bronchitis, and worsening systemic venous congestion are indications in those with normal ventricular function.

Results

Patients with ventricular dysfunction as the main indication had excellent early survival with no early mortality compared to 40% mortality in patients with normal ventricular function. Patients who survived to leave the hospital had however similar long-term outcomes. Two patients with protein-losing enteropathy resolved completely by one month. Normal ventricular function, pulmonary artery stenting, early Fontan failure (6 months), ascites, and need for desensitization were risk factors for early mortality. After the early acute phase of increased risk, the mortality risk plateaued off.

Conclusion

Transplantation in patients with single ventricle and ventricular dysfunction can be offered with a good early and late outcome. There is a need to have multi-institutional and multi-disciplinary collaboration along with work in basic sciences to better understand the effects of failed Fontan physiology with normal ventricular function.

Atrial function in the Fontan circulation: comparison with invasively assessed systemic ventricular filling pressure

Abnormal atrial mechanics in biventricular circulations have been associated with elevated left heart filling pressures. Similar associations in the Fontan circulation are unknown. The aim of this study was to examine the relationship between atrial mechanics and invasively assessed hemodynamic parameters late after the Fontan operation. Thirty-nine Fontan patients with echocardiographic and invasive hemodynamic studies done within 48 h were included and were compared to 40 age-matched healthy controls. Atrial and ventricular strain measurements were measured offline using 2-dimensional speckle-tracking. Mean age was 10.2 ± 6.7 years and 24 (62%) were male. Atrial strain measures were lower in Fontan patients compared to healthy controls. There was no significant association between atrial strain measurements and Fontan systemic ventricular filling pressures (SVFP) as indicated by pulmonary artery occlusion pressures, direct left atrial pressure or systemic ventricular end-diastolic pressure. Global atrial strain was not correlated with segmental atrial strain in the pulmonary venous atrium. Global atrial reservoir strain was positively correlated with pulmonary vascular resistance (r = 0.508, p = 0.045). Global atrial conduit strain was positively correlated with E/A ratio of the AV valve inflow (r = 0.555, p = 0.002). Atrial and ventricular strain measurements were not significantly correlated. In patients with a Fontan, global atrial function is significantly depressed, and is uncoupled from segmental left lateral atrial function. Global as well as segmental atrial mechanics are not significantly associated with SVFPs in Fontan patients. Instead, global atrial reservoir function appears to parallel pulmonary vascular resistance.

Determinants and Prognostic Implications of Left-Heart Filling Pressures in Tetralogy of Fallot

BACKGROUND

Elevated pulmonary artery wedge pressure (PAWP) is the hallmark of left-heart failure and is responsible for heart failure symptoms and mortality. Although PAWP typically correlates with right atrial pressure (RAP), it is primarily dependent on left-heart myocardial properties and volume status. As right-heart disease can occur in the absence of left-heart disease in patients with tetralogy of Fallot (TOF), we hypothesized that RAP was the primary determinant of PAWP in this population.

METHODS

A cohort study of adults with TOF that underwent right-heart catheterization at Mayo Clinic Rochester (1990 to 2017) to determine the relationship among RAP, PAWP, and mortality.

RESULTS

Among 213 patients (male 105; age 37 ± 14 years), the mean PAWP was 14 ± 5 mm Hg, and RAP was 11 ± 5 mm Hg. RAP was the strongest predictor of PAWP (β = 0.68, standard error = 0.06, P < 0.001), independent of left-heart disease and atherosclerotic cardiovascular risk factors. The patients with high PAWP also had normal tissue Doppler velocities, suggesting normal left-ventricular myocardial properties. PAWP was an independent predictor of death/transplant (hazard ration [HR] 1.11, 95% confidence interval [CI], 1.03-1.20, P = 0.004). However, when RAP was incorporated into the regression model, RAP (and not PAWP) became the independent predictor of outcomes (HR 1.14, 95% CI, 1.06-1.22, P = 0.001).

CONCLUSIONS

The current study showed that RAP was the primary determinant of PAWP and accounts, to some extent, for the mortality in patients with TOF and high PAWP. The data provide new insight in the pathophysiology of disease progression for symptomatic patients with TOF.

Heightened Dependence of Left-Heart Filling Pressures on Right-Heart Failure in Congenital Heart Disease

BACKGROUND

Pulmonary artery wedge pressure (PAWP) is often elevated in patients with right-sided congenital heart disease (CHD), raising the possibility of coexisting left-heart disease, but pressure-volume relationships in the left and right sides of the heart influence one another through interdependence, which may be amplified in patients with CHD.

METHODS

We hypothesized that increases in PAWP in patients with CHD would be more strongly related to ventricular interdependence compared with patients who have isolated left-heart disease such as heart failure with preserved ejection fraction (HFpEF). Ventricular interdependence was assessed by the relationship between PAWP and right-atrial pressure (RAP), RAP/PAWP ratio, and the left-ventricular (LV) eccentricity index.

RESULTS

PAWP was elevated (≥15 mm Hg) in 49% of patients with CHD (n = 449). There was a very strong correlation between RAP and PAWP in CHD (r = 0.81, P < 0.001) that greatly exceeded the respective correlation in HFpEF (n = 160; r = 0.58, P < 0.001; P < 0.001 between groups). RAP/PAWP ratio and LV eccentricity index were higher in CHD than HFpEF (1.26 ± 0.18 vs 1.05 ± 0.14, P = 0.007) and (0.80 ± 0.21 vs 0.59 ± 0.19, P < 0.001), respectively. RAP (but not PAWP) was an independent predictor of death/transplant (hazard ratio 1.86 per 5 mm Hg, 95% confidence interval, 1.39-2.45, P = 0.002).

CONCLUSIONS

Left-heart filling pressures are commonly elevated in right-sided CHD, but this is related predominantly to right-heart failure and enhanced ventricular interdependence rather than left-heart disease. These data provide new insight into the basis of abnormal left-heart hemodynamics in patients with CHD and reinforce the importance of therapeutic interventions targeted to the right heart.

Left ventricular filling pressure in Tetralogy of Fallot: Correlation between invasive and noninvasive indices

Background

Left heart filling pressures, as measured by pulmonary artery wedge pressure (PAWP), is associated with heart failure related mortality. Because of the prognostic importance of PAWP, several echocardiographic indices have been proposed for noninvasive assessment of PAWP. However, these indices have not been validated in the congenital heart disease population. The purpose of this study was to determine the correlation between echocardiographic indices of PAWP, and the effect of high PAWP on transplant-free survival in adults with tetralogy of Fallot (TOF).

Methods

Retrospective study of adult TOF patients that underwent cardiac catheterization at Mayo Clinic, 1990–2017. We selected these pre-defined set of echocardiographic indices of LV diastolic function: mitral valve early velocity (E), mitral valve early and late velocity ratio (E/A), mitral valve deceleration time (DT), mitral annular tissue Doppler early velocity (e′), and left atrial volume index (LAVI).

Results

Of the echocardiographic indices analyzed among 213 patients (age 37 ± 14 years), only E velocity (β = 5.83, standard error = 1.52, p < 0.001) and LAVI (β = 0.14, standard error = 0.05, p = 0.007) correlated with PAWP. LAVI > 28 ml/m² had sensitivity of 79% and specificity of 63% (AUC 0.712), and E velocity > 1.0 m/s had sensitivity of 66% and specificity of 89% (AUC 0.692), for detecting PAWP > 15 mmHg. LAVI > 28 ml/m² was associated with reduced 10-year transplant-free survival (49% vs 90%, p < 0.001).

Conclusion

This study supports the use of LAVI for noninvasive assessment of PAWP and for prognostication. Further studies are required to validate these results in a different population.

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.