Fetal ventricular strain in uncomplicated and selective growth restricted monochorionic diamniotic pregnancies, with cardiovascular responses in pre-TTTS

Christoph Wohlmuth, Arpit Agarwal, Blair Stevens, Anthony Johnson, Kenneth J Moise, Ramesha Papanna, Roopali Donepudi, Cynthia S Bell, Ian E Averiss, Helena M Gardiner
Ultrasound in Obstetrics & Gynecology 2019 November 4

OBJECTIVES: The primary aim of this prospective, blinded study was to confirm whether inter-twin pair discordance in ventricular strain and ductus venosus time intervals predicts twin-twin transfusion syndrome (TTTS). Secondary aims using uncomplicated monochorionic diamniotic (MCDA) pregnancies were the creation of gestational age ranges for ventricular strain in those without selective intrauterine growth restriction (sIUGR) and the characterization of the relationship of ventricular strain with those with sIUGR.

METHODS: We enrolled 150 MCDAs consecutively into a prospective study of left and right ventricular global longitudinal strain (2015-2018). Four-chamber clips recorded at ultrasound surveillance were blinded to twin-pair and outcome for offline strain measurement, between the usual development of TTTS (16 to 26 completed gestational weeks). Uncomplicated MCDAs, without sIUGR, were used as controls to test the association between strain, gestational age and estimated fetal weight using mixed-effects multilevel regression. Inter-rater correlation was tested in 208 strain measurements and within-fetus variation in 16 controls, where multiple 4-chamber views were taken on the same day. The effect of sIUGR on strain in otherwise uncomplicated MCDAs was analyzed. "Pre-TTTS" was defined as MCDA pregnancies referred for TTTS evaluation, who did not satisfy Quintero staging criteria, but subsequently developed TTTS requiring laser treatment. Cardiovascular parameters measured in "pre-TTTS" included tissue Doppler and ductus venosus early filling time as a percentage of cardiac cycle (DVeT%). Inter-twin pair strain and DVeT% discordance was compared between controls and "pre-TTTS", matched for gestational age.

RESULTS: Paired strain data were available for inter-twin comparison in 128/150 MCDAs, comprising 14 "pre-TTTS" and 113 controls after exclusions. Scans were collected at a median frame rate of 97 Hz (range 28-220). Laser was performed at median of 20.6 (range 17.2-26.6) weeks' gestation. There were no group differences in right or left ventricular (RV or LV) strain discordance between 68/127 MCDA controls and 13/14 "pre-TTTS" pregnancies below 20 completed gestational weeks (RV: p=0.338, LV: p=0.932). DVeT% discordance >3.6% was found in 8/13 "pre-TTTS". In controls, the estimated variability in ventricular strain within each twin during the day was high (19.7 RV, 12.9 LV). However, within each pair (between fetus variation) variability was low (5.5 RV, 2.9 LV). Interclass correlation reflecting the proportion of total variability represented by the variability between twin pairs was low (0.22 RV, 0.18 LV). Both RV (p<0.001) and LV (p=0.025) strain showed a negative association with gestational age. LV strain was on average 1.83 higher in sIUGR compared to normally grown fetuses (p = 0.023) in MCDA controls with no statistically significant difference in RV strain (p=0.271).

CONCLUSIONS: Although we have previously reported ventricular strain as a possible predictor of developing TTTS, we found no significant inter-group differences in "pre-TTTS", compared with age-matched MCDA controls in this blinded prospective study. We recommend DVeT% discordance may be a more practical screening tool in MCDA pregnancies. This study also provides new information on the gestational change, biological and technical variation of global longitudinal ventricular strain in uncomplicated MCDAs and those with isolated sIUGR. This article is protected by copyright. All rights reserved.

Full Text Links

Find Full Text Links for this Article


You are not logged in. Sign Up or Log In to join the discussion.

Related Papers

Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"