Background: Abnormalities of the cardiovascular (CV) system play an important role in the pathophysiology of twin-twin transfusion syndrome (TTTS). Currently there is no means of quantifying overall degree of CV derangement in TTTS.
Objective: To develop a tool that describes the magnitude of CV abnormality in TTTS.
Methods/Results: Fetal echocardiograms of 100 twin-pairs referred for TTTS were reviewed. We applied a novel 20 point Score to each set. The Score is designed to characterize the unique cardiovascular findings and is a composite of variables that include: (1) recipient assessment of heart size, ventricular hypertrophy, systolic function, valve regurgitation, pulmonary arterial size relative to aorta (as a measure of relative pulmonary stenosis) and diastolic filling properties, as well as (2) donor assessment of diastolic umbilical arterial flow as a measure of placental vascular resistance. Variables are recorded as normal=0, mildly abnormal=1, or severely abnormal=2. The Score correlates well with myocardial performance (Tei) index in the recipient RV and correlates with other measures of disease severity (Quintero) but is additive in informing upon the CV state. Thirty-two patients underwent placental laser photocoagulation treatment and exhibited a significant decrease in Score (9+5 versus 4+3, p<0.001) within 2 weeks after intervention.
Conclusions: The CHOP Score characterizes the magnitude of CV abnormality in TTTS, is disease specific, and can be applied to (1) grade severity at initial presentation and serial follow up, (2) assess efficacy of treatment strategies and (3) prognosticate for development of residual long-term derangements that may present after birth, into adulthood.