Matthew Campbell, Brian R White, Jack Rychik, Jarrett Linder, Jennifer A Faerber, Zhiyun Tian, Meryl S Cohen. J Am Soc Echocardiogr. 2022 Nov;35(11):1168-1175. doi: 10.1016/j.echo.2022.07.007. Epub 2022 Jul 19. PMID: 35863543
- Fetal spectral doppler assessment of the vertical vein predicts severe postnatal obstruction in Total Anomalous Pulmonary Venous Connection and may impact clinical care
- Pulmonary Venous Variability Index (PVVI) and Minimum velocity of pulmonary vein (Vmin) – both as quantitative metrics are associated with severe postnatal pulmonary vein obstruction
Commentary from Dr. Venu Amula (Salt Lake City, UT, USA), section editor of Pediatric & Fetal Cardiology Journal Watch
Total Anomalous Pulmonary Venous connection with severe postnatal obstruction is one of the few existing pediatric cardiac surgical emergencies. Neonates without prenatal diagnosis and severe postnatal obstruction present with hypoxia, acidosis, respiratory failure, and circulatory collapse. Prenatal diagnosis may lead to safe planning of fetal delivery and prevention of preoperative morbidity. The degree of obstruction of the anomalous vein is variably estimated by qualitative methods and is somewhat subjective. The authors in the current study evaluate a quantitative metric based on spectral doppler evaluation of vertical vein called Pulmonary Venous Variability Index and hypothesize that fetal PVVI and vertical vein Doppler velocities are associated with severe pulmonary vein obstruction postnatally.
The authors performed a retrospective cohort study of all neonates with a prenatal diagnosis of TAPVC who underwent fetal echocardiography with spectral doppler interrogation of the vertical vein at Children’s Hospital of Philadelphia. The latest gestation echocardiogram was used to examine the maximum velocity (V max ), mean velocity (V mean ), and minimum velocity (V min ) in the pulmonary venous pathway as well as fetal PVVI. The PVVI was defined as (V max − V min )/V mean. The study hypothesized that PVVI is an effective Doppler tool to predict postnatal pulmonary venous obstruction in TAPVC. The primary outcome evaluated was severe postnatal obstruction, a composite of preoperative death, and surgical or catheter-based intervention on the first day of life. Secondary clinical outcomes are preoperative intubation, preoperative acidosis (pH < 7.35), preoperative hypoxemia (oxygen saturation < 90% for two-ventricle patients and <75% for single-ventricle patients), postnatal cardiac catheterization variables, and chest radiographic findings.
Twenty-nine patients met the study inclusion criteria. Twelve of the 29 patients (41%) met the primary outcome criteria. In the univariate analysis, heterotaxy, single-ventricle heart disease, TAPVC type, and having the fetal echocardiogram qualitatively read as obstructed were all not associated with severe pulmonary vein obstruction. Lower PVVI was associated with a greater risk for severe pulmonary venous obstruction ( P = .008). The vertical vein’s maximum, mean, and minimum velocities were all significantly associated with severe pulmonary venous obstruction ( P = .03, P = .03, and P = .007, respectively) – with minimum velocity showing a strong association. All of the absolute velocity metrics were associated with secondary outcomes of preoperative intubation and dichotomized outcome of hypoxia, PVVI was not.
The correlation between early and late prenatal echocardiograms was moderate for PVVI and good for the absolute velocity metrics. The interobserver measurement reproducibility was excellent, with an intraclass correlation coefficient of >or = 0.9. The study was limited by a small sample size that limits multivariate analysis. The results are also confounded by the sampling bias of the population from a large tertiary academic center where referrals are often made for high-risk deliveries. However, low fetal PVVI and high Vmin predicted severe postnatal pulmonary vein obstruction in this study cohort and can be used in quantitative analysis of TAPVC prenatally.