Factor II

Effect of Maternal Obstructive Sleep Apnea-Hypopnea on 24-Hour Blood Pressure, Nocturnal Blood Pressure Dipping and Arterial Stiffness in Hypertensive Disorders of Pregnancy

Rationale: Maternal obstructive sleep apnea-hypopnea (OSAH) is associated with hypertensive disorders of pregnancy (HDP). Attenuation of the normal nocturnal blood pressure (BP) decline (non-dipping) is associated with adverse pregnancy outcomes. OSAH is associated with nocturnal non-dipping in the general population, but this has not been studied in pregnancy. We therefore analyzed baseline data from an ongoing RCT (NCT03309826) assessing the impact of OSAH treatment on HDP outcomes, to evaluate the relationship of OSAH to 24-h BP profile, in particular nocturnal BP dipping, and measures of arterial stiffness.

Methods: Women with a singleton pregnancy and HDP underwent level II polysomnography. Patients with OSAH (apnea-hypopnea index (AHI) ≥ 5 events/h) then underwent 24-h ambulatory BP monitoring and arterial stiffness measurements (applanation tonometry, SphygmoCor). Positive dipping was defined as nocturnal systolic blood pressure (SBP) dip ≥ 10%. The relationships between measures of OSAH severity, measures of BP and arterial stiffness were evaluated using linear regression analyses.

Results: We studied 51 HDP participants (36.5 ± 4.9 years, BMI 36.9 ± 8.6 kg/m²) with OSAH with mean AHI 27.7 ± 26.4 events/h at 25.0 ± 4.9 weeks’ gestation. We found no significant relationships between AHI or other OSA severity measures and mean 24-h BP values, although BP was generally well-controlled. Most women were SBP non-dippers (78.4%). AHI showed a significant inverse correlation with % SBP dipping following adjustment for age, BMI, parity, gestational age, and BP medications (β = −0.11, p = 0.02). Significant inverse correlations were also observed between AHI and DBP (β = −0.16, p = 0.01) and MAP (β = −0.13, p = 0.02) % dipping. Oxygen desaturation index and sleep time below SaO₂ 90% were also inversely correlated with % dipping. Moreover, a significant positive correlation was observed between carotid-femoral pulse wave velocity (cfPWV) and REM AHI (β = 0.02, p = 0.04) in unadjusted but not adjusted analysis.

Conclusion: Blood pressure non-dipping was observed in a majority of women with HDP and OSAH. There were significant inverse relationships between OSAH severity measures and nocturnal % dipping. Increased arterial stiffness was associated with increasing severity of OSAH during REM sleep in unadjusted although not adjusted analysis. These findings suggest that OSAH may represent a therapeutic target to improve BP profile and vascular risk in HDP.

Combining biochemical and ultrasonographic markers in predicting preeclampsia: a systematic review

BACKGROUND

Early identification of pregnant women at risk for preeclampsia is a priority to implement preventive measures. Some biochemical and ultrasonographic parameters have shown promising predictive performance, but so far there is no clinically validated screening procedure.

CONTENT

Using a series of keywords, we reviewed electronic databases (Medline, Embase, all records to May 2009) reporting the performance of biological and ultrasonographic markers to predict preeclampsia, both single markers and combinations of markers. We analyzed the data according to gestational age and risk levels of the studied populations. We evaluated the methodological quality of included publications using QUADAS (quality assessment of diagnostic accuracy studies). We identified 37 relevant studies that assessed 71 different combinations of biochemical and ultrasonographic markers. Most studies were performed during the second trimester on small-scale high-risk populations with few cases of preeclampsia. Combinations of markers generally led to an increase in sensitivity and/or specificity compared with single markers. In low-risk populations, combinations including placental protein 13 (PP13), pregnancy-associated plasma protein A (PAPP-A), a disintegrin and metalloprotease-12 (ADAM12), activin A, or inhibin A measured in first or early second trimester and uterine artery Doppler in second trimester appear promising (sensitivity 60%-80%, specificity >80%). In high-risk populations, the combination of PP13 and pulsatility index in first trimester showed 90% sensitivity and 90% specificity in a single study limited to severe preeclampsia.

SUMMARY

Combinations of biochemical and ultrasonographic markers improved the performance of early prediction of preeclampsia. From a perspective of integrative medicine, large population-based studies evaluating algorithms combining multiple markers are needed, if screening approaches are to be eventually implemented.

Predicting Transformation from Gestational Hypertension to Preeclampsia in Clinical Practice: A Possible Role for 24 Hour Ambulatory Blood Pressure Monitoring

OBJECTIVE

To identify parameters that may assist clinicians in predicting which women will develop preeclampsia (PE) after initially presenting with gestational hypertension (GH).

METHODS

118 women were recruited to the study with GH or PE. They were divided into three groups based on their diagnosis at delivery- (1) GH, (2) PE from the time of presentation, (3) those with an initial diagnosis of GH who progressed to PE. Women underwent 24 hour ambulatory blood pressure monitoring (ABPM) and had serum estrogen, progesterone, beta-HCG, leptin and adiponectin measured as possible predictors of transformation of GH to PE.

RESULTS

Women who presented with GH, and progressed to PE, presented four weeks earlier (33 vs 37 weeks, p < 0.001) than those who did not progress. Women with PE, either as their initial diagnosis or after progression from GH, were delivered earlier (p < 0.001) and had more small for gestational age (SGA) babies than women with GH at delivery (p < 0.05). Those who developed PE after presenting with GH generally had higher blood pressures than those who remained as GH, significant for awake and 24 hour systolic blood pressures (p < 0.05). beta-HCG, estrogen, progesterone or leptin values were similar across the groups. Adiponectin was higher in women with established PE at presentation compared to women with GH (p = 0.02) but adiponectin failed to discriminate those women with an initial diagnosis of GH who progressed to PE.

CONCLUSION

24 hr ABPM may provide a non-invasive method of identifying this 'at risk' GH population, particularly in the case of early presentation.

Total vascular resistance and left ventricular morphology as screening tools for complications in pregnancy

We evaluated the predictive value of elevated total vascular resistance on the outcome of pregnancy in normotensive high-risk primigravidas with bilateral notching of the uterine artery Doppler. A total of 526 high-risk primigravidas referred to the obstetrics outpatient clinic of Tor Vergata University with bilateral notching of the uterine artery at 20 to 22 weeks' gestation were submitted to a maternal echocardiographic examination and uterine artery Doppler evaluation at 24 weeks' gestation. Blood pressure was recorded at the time of the examination, total vascular resistance was calculated, and the geometric pattern of the left ventricle was assessed. Patients were followed until the end of pregnancy to detect fetal/maternal adverse outcomes (gestational hypertension, preeclampsia, abruptio placentae, fetal growth restriction, perinatal death, etc). A total of 111 of the 526 pregnancies showed a bilateral notch at 24 weeks' gestation, and 97 had an adverse outcome (18.44%). The best independent predictor for maternal and fetal complications was total vascular resistance (odds ratio: 91.25; 95% CI: 39.64 to 210.05; P<0.001). The cutoff value was 1400 dynes x s x cm(-5), with a sensitivity and a specificity of 89% and 94%, respectively. A high relative wall thickness of the left ventricle (>0.37; odds ratio: 2.47; 95% CI: 1.12 to 5.44) and a hypertrophized ventricle (left ventricular mass >130 g; odds ratio: 2.52; 95% CI: 1.12 to 5.64) were also independent predictors (P<0.05). Echocardiography might identify at 24 weeks' gestation patients who subsequently develop maternal and fetal complications through the assessment of maternal hemodynamics and left ventricular geometry.