Utility of Umbilical Artery Doppler !in Preterm Premature Rupture of Membranes!

Erica Heitmann, Mary M. Gerkovich !Karen Williams, George Lu, Laura Arnold, Abrea Roark, Dev Maulik!

University of Missouri-Kansas City School of Medicine!!Abstract!

 Introduction: Preterm birth (PTB) accounts for 12.7% of all live births in the United States and is a major contributor to neonatal morbidity and mortality. Preterm premature rupture of membranes (PPROM) occurs in 30-40% of PTB, most frequently leading to delivery within seven days of rupture. Underlying inflammation within the placenta is a possible cause of PPROM. Inflammation causes a release of prostaglandins, which may induce vasoconstriction of the placental vasculature, preterm labor, and PPROM. Vasoconstriction may increase resistance in the umbilical artery, which can be assessed using Doppler (ultrasound measure of blood velocity and resistance). The hypothesis tested in this study is that Doppler-derived measures of the umbilical artery in PPROM patients will be predictive of latency (time from PPROM to delivery) Methods: All charts on patients (N =964) having an ultrasound performed with the indication PPROM over a10 year period were reviewed. Doppler-derived measures, S/D (systolic/diastolic) and RI (resistive index), along with other clinical measures, were assessed. S/D measures the peak and nadir of the Doppler waveform, whereas the RI is a mathematical calculation of the S/D (S-D/S). The RI is a more useful measure because it can be calculated even in instances where the D value is a zero unlike the S/D. Continuous Doppler data were categorized as normal/abnormal using standardized cut-points. Poisson regression analysis was used for hypothesis testing. Results: A subset of 159 patients (72% Caucasian, mean age 28.5 years) who had Doppler data on the same day as admission for PPROM were used. Results showed abnormal Doppler value, alone,was not predictive of latency, for either S/D or RI (IRR 0.68, 95% CI= 0.36-1.26, p = 0.22; IRR 0.81, 95% CI= 0.44-1.49, p = 0.50, respectively). A second regression model was fit controlling for cervical dilation. These results confirmed that neither S/D nor RI were predictive of latency when entry cervical dilation was controlled (IRR 0.64, 95% CI = 0.33-1.24, p = .19; IRR 0.78, 95% CI= 0.41-1.50, p = 0.46, respectively). Conclusions: S/D and RI Doppler measures of the umbilical artery in PPROM patients are not predictive of latency.    

               

Methods! v Retrospective chart review over 10-year

period of all patients with PPROM v  Inclusion Criteria:

v Confirmed PPROM v Doppler performed same day as

admission v Singleton uncomplicated pregnancies !

Results!!!

Conclusions!!v Doppler is not predictive of latency in

patients with PPROM, regardless of index used

964  pa'ents  eligible  for  inclusion  by  ultrasound  

database  

175  exclusion  criteria   72  Doppler  data  not  available  

109  PPROM  not  diagnosed   346  pa'ents  included  

320  pa'ents  included  in  main  analysis  

159  pa'ents  with  Doppler  on  same  day  as  admission  

26  managed  expectantly  at  >34weeks  

267  hospital  records  not  available  

Characteris+c   N  (%)   Mean            (SD)  

Median    (IQR)  

Age   28.47          (6.41)  

28.00          (23-­‐33)  

Caucasian   115  (71.9)  

Black   27  (16.9)  

Gravida   2.62                (1.6)  

2.00                      (1-­‐3)  

Para   1.03                (1.1)  

1.00                      (0-­‐2)  

GA  PPROM   28.84            (3.5)  

29.36    (26.3-­‐31.9)  

GA  Delivery   29.97            (3.4)  

31.00    (27.3-­‐31.0)  

Latency  (days)   8.12            (10.1)  

4.97    (2.0-­‐10.0)  

Figure 1. Flow Diagram of Inclusion Criteria

Figure 2. Days Latency based on Doppler Findings

Figure 3. Latency Based on RI and Cervical Dilation

Figure 4. Latency based on S/D and Cervical Dilation

Table 1. Demographics.

86%   14%   90.5%   9.5%