From the Research
Persistent left superior vena cava (PLSVC) is most commonly associated with heterotaxy syndrome. This association is due to the fundamental disruption in normal left-right patterning during embryonic development that affects both the cardiac structures and systemic venous return. The strongest evidence for this association comes from a study published in 2006 1, which found that 45% of cases with PLSVC were associated with heterotaxy syndromes. Other studies have also reported a high prevalence of PLSVC in patients with heterotaxy syndrome, including a study published in 2007 2 that found 41% of fetuses with PLSVC had heterotaxy syndrome. Although PLSVC can occasionally be found in patients with other genetic conditions like Trisomy 21 or 22q11 deletion syndrome, the evidence suggests that heterotaxy syndrome is the most common association. Some key points to consider include:
- Heterotaxy syndrome is characterized by abnormal arrangement of thoracoabdominal organs across the left-right axis of the body, often accompanied by complex cardiovascular malformations.
- PLSVC can occur as an isolated finding in about 0.3-0.5% of the general population, but it has a significantly higher prevalence in patients with heterotaxy syndrome.
- The prognosis of affected fetuses largely depends on whether or not the PLSVC is associated with a congenital heart defect (CHD) or other anomalies.
- A thorough examination of the fetus is necessary to identify additional cardiac and extracardiac anomalies when PLSVC is detected. Studies have shown that the clinical significance of PLSVC depends on the drainage site and the accompanying cardiac anomalies, and that it can lead to significant problems such as arrhythmias and cyanosis 3. However, when PLSVC occurs in isolation, it is often asymptomatic and may not affect the outcome 1, 2. In clinical practice, it is essential to consider the possibility of heterotaxy syndrome when PLSVC is detected, and to perform a thorough evaluation to identify any associated anomalies.