Understanding Early Fontan Failure in Vietnam: Incidence and Clinical Predictors

BackgroundWe aimed to determine the incidence of early Fontan failure (EFF) in a contemporary series of patients from Vietnam and identify risk factors for EFF.MethodsA total of 145 consecutive patients underwent the Fontan procedure at E hospital in Vietnam from August 2012 through December 2019. We analyzed predictive factors for EFF based on clinical evaluation, literature review, and our institutional database. The primary outcome assessed was EFF.ResultsThe incidence of EFF was 9.66%. In a univariate analysis of preoperative data, the anatomic diagnosis of unbalanced atrioventricular (AV) septal defect, situs inversus, AV valve regurgitation, large aortopulmonary circulation on Doppler echocardiogram, elevated pulmonary artery pressure (PAP), and elevated pulmonary vascular resistance (PVR) were significantly associated with EFF. Four intraoperative risk factors influencing EFF included pulmonary artery reconstruction, AV valve repair, bleeding, and elevated PAP. Postoperative edema was also significantly associated with EFF. A total of 22 potential independent variables were put into a model with multivariate logistic regression analysis. A final reduced model following utilizing a stepwise backward selection strategy indicated preoperative elevated PAP (odds ratio [OR]: 1.84, 95% CI: 1.12-3.00, P = .016), AV valve repair at Fontan (OR: 65.85, 95%CI: 1.95-2228.14, P = .020), and postoperative elevated PAP (OR: 1.66, 95%CI: 1.19-2.33, P = .004) were independent predictors for EFF.ConclusionEarly Fontan failure was relatively high in our case series and was associated with a significant mortality rate. Patients with single ventricle physiology having preoperative elevated PAP, intraoperative AV valve repair, and postoperative elevated PAP were identified as independent risk factors to predict EFF. Particularly, in the context of a developing country with limited health care resources, a comprehensive management strategy that targets the variable predictors for EFF should be incorporated with previously known risk factors to avoid EFF.

Defining the causes for Fontan circulatory failure in total cavopulmonary connection patients

OBJECTIVES

This study aims to identify the causes of failure in Fontan patients with a total cavopulmonary connection.

METHODS

We conducted a comprehensive review of all patients who underwent a total cavopulmonary connection procedure at our centre between 1988 and 2023, aiming to identify and analyse the factors contributing to Fontan failure (defined as mortality, heart transplantation, Fontan takedown, protein-losing enteropathy, plastic bronchitis or New York Heart Association Functional Classification class III or IV).

RESULTS

The study included 217 patients (median age at time of Fontan completion 3.7 years) with a median follow-up of 12.7 years (interquartile range 7.2-17.7). Systolic ventricular function decreased significantly over time in patients with right ventricular dominant morphology (P = 0.002), while systolic ventricular function remained stable in patients with left ventricular dominant morphology. Fontan failure occurred in 24 patients, with estimated freedom from Fontan failure rates of 97.7% [95% confidence interval (CI), 95-99] at 1 year, 93.9% (95% CI, 89-97) at 15 years and 77.2% (95% CI, 65-86) at 20 years of follow-up. Systolic ventricular dysfunction was the most common cause of failure (29%), followed by atrioventricular valve regurgitation (16.7%), a high pulmonary vascular resistance (16.7%), restrictive pathophysiology (16.7%) and obstruction (12.5%). Patients with right ventricular dominance developed most often systolic ventricular dysfunction, while patients with left ventricular dominant morphology developed most often restrictive pathophysiology or a high pulmonary vascular resistance.

CONCLUSIONS

Approximately 10% of patients experienced Fontan failure within 15 years postoperatively. Patients with right ventricular dominance experienced progressive decline due to systolic dysfunction, while those with left ventricular dominance exhibited failure due to restrictive pathophysiology or high pulmonary vascular resistance.

Failures of the Fontan System in Univentricular Hearts and Mortality Risk in Heart Transplantation: A Systematic Review and Meta-Analysis

The Fontan procedure (FP) is the standard surgical treatment for Univentricular heart diseases. Over time, the Fontan system fails, leading to pathologies such as protein-losing enteropathy (PLE), plastic bronchitis (PB), and heart failure (HF). FP should be considered as a transitional step to the final treatment: heart transplantation (HT). This systematic review and meta-analysis aims to establish the risk of death following HT according to the presence of FP complications. There was a total of 691 transplanted patients in the 18 articles, immediate survival 88% (n = 448), survival from 1 to 5 years of 78% (n = 427) and survival from 5.1 to 10 years of 69% (n = 208), >10 years 61% (n = 109). The relative risk (RR) was 1.12 for PLE (95% confidence interval [CI] = 0.89-1.40, p = 0.34), 1.03 for HF (0.7-1.51, p = 0.88), 0.70 for Arrhythmias (0.39-1.24, p = 0.22), 0.46 for PB (0.08-2.72, p = 0.39), and 5.81 for CKD (1.70-19.88, p = 0.005). In patients with two or more failures, the RR was 1.94 (0.99-3.81, p = 0.05). After FP, the risk of death after HT is associated with CKD and with the presence of two or more failures.

A Review of Physiologic Considerations and Challenges in Pediatric Patients With Failing Single- Ventricle Physiology Undergoing Ventricular Assist Device Placement

Advances in surgical techniques and outpatient cardiac care have led to a growing population of pediatric patients surviving well into adulthood with previous single-ventricle palliation. Continued improvement in survival has resulted in subsequent increases in the number of patients with single-ventricle physiology listed for heart transplantations. Some of these patients require mechanical circulatory support as a bridge to transplantation, although establishing successful mechanical circulatory support in these complex patients remains challenging. Only limited published data exist describing the perioperative anesthetic management and key considerations dedicated to patients with failing single-ventricle physiology presenting for ventricular assist devices. This clinical review aims to provide a focused evaluation of the vital perioperative considerations encountered in this novel population.

Abnormal pulmonary perfusion heterogeneity in patients with Fontan circulation and pulmonary arterial hypertension

KEY POINTS

The distribution of pulmonary perfusion is affected by gravity, vascular branching structure and active regulatory mechanisms, which may be disrupted by cardiopulmonary disease, but this is not well studied, particularly in rare conditions. We evaluated pulmonary perfusion in patients who had undergone Fontan procedure, patients with pulmonary arterial hypertension (PAH) and two groups of controls using a proton magnetic resonance imaging technique, arterial spin labelling to measure perfusion. Heterogeneity was assessed by the relative dispersion (SD/mean) and gravitational gradients. Gravitational gradients were similar between all groups, but heterogeneity was significantly increased in both patient groups compared to controls and persisted after removing contributions from large blood vessels and gravitational gradients. Patients with Fontan physiology and patients with PAH have increased pulmonary perfusion heterogeneity that is not explainable by differences in mean perfusion, gravitational gradients, or large vessel anatomy. This probably reflects vascular remodelling in PAH and possibly in Fontan physiology.

ABSTRACT

Many factors affect the distribution of pulmonary perfusion, which may be disrupted by cardiopulmonary disease, but this is not well studied, particularly in rare conditions. An example is following the Fontan procedure, where pulmonary perfusion is passive, and heterogeneity may be increased because of the underlying pathophysiology leading to Fontan palliation, remodelling, or increased gravitational gradients from low flow. Another is pulmonary arterial hypertension (PAH), where gravitational gradients may be reduced secondary to high pressures, but remodelling may increase perfusion heterogeneity. We evaluated regional pulmonary perfusion in Fontan patients (n = 5), healthy young controls (Fontan control, n = 5), patients with PAH (n = 6) and healthy older controls (PAH control) using proton magnetic resonance imaging. Regional perfusion was measured using arterial spin labelling. Heterogeneity was assessed by the relative dispersion (SD/mean) and gravitational gradients. Mean perfusion was similar (Fontan = 2.50 ± 1.02 ml min^-1  ml^-1 ; Fontan control = 3.09 ± 0.58, PAH = 3.63 ± 1.95; PAH control = 3.98 ± 0.91, P = 0.26), and the slopes of gravitational gradients were not different (Fontan = -0.23 ± 0.09 ml min^-1  ml^-1  cm^-1 ; Fontan control = -0.29 ± 0.23, PAH = -0.27 ± 0.09, PAH control = -0.25 ± 0.18, P = 0.91) between groups. Perfusion relative dispersion was greater in both Fontan and PAH than controls (Fontan = 1.46 ± 0.18; Fontan control = 0.99 ± 0.21, P = 0.005; PAH = 1.22 ± 0.27, PAH control = 0.91 ± 0.12, P = 0.02) but similar between patient groups (P = 0.13). These findings persisted after removing contributions from large blood vessels and gravitational gradients (all P < 0.05). We conclude that patients with Fontan physiology and PAH have increased pulmonary perfusion heterogeneity that is not explained by differences in mean perfusion, gravitational gradients, or large vessel anatomy. This probably reflects the effects of remodelling in PAH and possibly in Fontan physiology.

Ventricular assist device use in single ventricle congenital heart disease

As VAD have become an effective therapy for end-stage heart failure, their application in congenital heart disease has increased. Single ventricle congenital heart disease introduces unique physiologic challenges for VAD use. However, with regard to the mixed clinical results presented within this review, we suggest that patient selection, timing of implant, and center experience are all important contributors to outcome. This review focuses on the published experience of VAD use in single ventricle patients and details physiologic challenges and novel approaches in this growing pediatric and adult population.

Fontan Outcomes and Pulmonary Blood Flow at Birth

We previously noted, in a small group of post-Fontan patients, a possible association between hepatic fibrosis scores and the status of pulmonary blood flow at birth. To further explore this observation, we examined data from all Fontan patients seen in our center from July 2010 to March 2015. We identified 200 patients for analysis. Of the 200 patients, 56 underwent transvenous-hepatic biopsy. Of the 200 patients, 13 (6.5%) had protein-losing enteropathy. We divided both the 56 biopsy patients and the entire cohort of 200 patients into 4 groups: (1) unobstructed pulmonary blood flow at birth with functional left ventricles, (2) unobstructed pulmonary blood flow at birth with functional right ventricles, (3) obstructed pulmonary blood flow at birth with functional left ventricles, and (4) obstructed pulmonary blood flow at birth with functional right ventricles. Analysis of the 56 liver-biopsy patient groups showed median hepatic total-fibrosis scores for the 4 groups of 2 (0-6), 2 (0-8), 3 (2-6), and 4 (1-8), respectively, with statistical significance between groups 4 and 1 (p = 0.031). For the entire cohort of 200 patients, we analyzed the incidence of protein-losing enteropathy for each of the four groups and found protein-losing enteropathy percent occurrences of 0, 2.9, 8.8, and 16.1, respectively, with statistical significance between groups 4 and 2 (p = 0.031) and between groups 4 and 1 (p = 0.025). A history of obstructed pulmonary blood flow at birth, coupled with a functional right ventricle, may predict a poorer long-term Fontan outcome.