Univentricular Heart Survival: How Morphology Impacts Outcomes
"New research highlights the critical role of ventricular morphology in predicting survival rates for patients with univentricular hearts, offering insights for improved risk stratification and treatment strategies."
Congenital heart defects (CHDs) present a significant challenge in pediatric cardiology, with univentricular hearts (UVH) representing some of the most complex cases. In UVH, one ventricle is underdeveloped, requiring a series of surgical interventions to establish a functional circulation. While advances in surgical techniques and medical management have improved survival rates, long-term outcomes remain a concern. Understanding the factors that influence survival is crucial for optimizing patient care and improving prognosis.
Among the various factors influencing outcomes in UVH, ventricular morphology has emerged as a key area of interest. Specifically, the distinction between single right ventricular morphology (SRV) and single left ventricular morphology (SLV) has garnered attention. SRV involves a dominant right ventricle with a rudimentary left ventricle, while SLV features a dominant left ventricle with a rudimentary right ventricle. The impact of these morphological variations on survival rates has been a subject of ongoing research, with conflicting evidence and a need for clearer understanding.
To address this gap in knowledge, a recent study published in Open Heart sought to investigate the prognostic significance of SRV versus SLV in patients with UVH. By analyzing data from 395 patients who underwent surgery at a single center over several decades, the researchers aimed to determine whether ventricular morphology could serve as a reliable predictor of survival. The findings of this study shed new light on the importance of ventricular morphology in risk stratification and treatment planning for patients with UVH.
SRV vs. SLV: Unveiling the Survival Disparity in Univentricular Hearts
The study, conducted at Oslo University Hospital, prospectively included 395 patients with UVH who underwent surgical intervention between 1972 and 2016. The patient cohort comprised 195 individuals with SRV, 166 with SLV, and 34 with mixed or indeterminate ventricular morphology. Data collected included diagnoses, UVH morphology, types of operations performed, and the timing and causes of death or heart transplantation (HTX). The primary endpoint of the study was death or HTX.
- Increased Mortality in SRV Patients: The study revealed a significant disparity in survival rates between patients with SRV and SLV. Among the 111 non-Fontan patients, 88 deaths occurred, with a disproportionately higher number in the SRV group (62 vs. 20 in the SLV group, p<0.0001). Heart failure was identified as a major contributor to mortality, with 23 deaths attributed to heart failure in the SRV group compared to only 5 in the SLV group (p=0.0012).
- Impact of Fontan Procedure: Among the 284 patients who underwent the Fontan procedure, 25-year cumulative survival rates were significantly higher in the SLV group (87.9%) compared to the SRV group (66.9%, p=0.0027). This difference was partly attributed to a higher incidence of death or HTX due to heart failure among patients with SRV (p=0.0006).
- SRV as a Strong Predictor: Multivariable proportional hazards analyses confirmed that SRV was a strong predictor of death or HTX, with a hazard ratio of 3.3 (95% CI 1.6 to 6.6). This finding underscores the independent association between ventricular morphology and adverse outcomes in patients with UVH.
Translating Findings into Clinical Practice: A Call for Personalized Care
This study provides compelling evidence that ventricular morphology plays a critical role in determining survival outcomes for patients with UVH. The identification of SRV as a strong predictor of mortality and heart failure underscores the need for incorporating ventricular morphology into risk stratification algorithms and treatment strategies. Clinicians should consider ventricular morphology during the initial evaluation of patients with UVH and tailor their management plans accordingly.