Evaluation of Non-invasive Central Aortic Hemodynamics in an Obstetric Inner-City Population: An Observational Study

Background: Women presenting for delivery at Cooper University HealthCare have a 2.7 fold greater rate of hypertension (HTN) compared to similarly sized hospitals in New Jersey. The presence of HTN with pregnancy may have short and long-term consequences for the patient. However, evaluation of systolic blood pressure (bSBP) with brachial artery measurements has been shown to lead to an overestimation when compared with central aortic systolic blood pressure (cSBP). Non-invasive measurement of cSBP with the Sphygmocor Xcel blood pressure device (Cardiex, Inc) consistently demonstrates that bSBP is on average 11 mmHg greater than cSBP. The current observational study investigated this issue in an inner-city OB population. In addition, the Xcel device provides quantification of augmentation pressure (AP, a measure of arterial wave reflections), wasted pressure work (WPW) and the subendocardial viability ratio (SEVR), a metric of coronary flow reserve. Methods: Women presenting to Cooper University HealthCare (CUHC) for delivery were consented and enrolled (n=23, age: 31.5 ± 4.6). Blood pressures measurements were made in triplicate to create the mean of bSBP with cSBP, respectively. The following parameters were measured: bSBP, cSBP, aortic diastolic pressure (diaP). Calculated parameters included pulse and augmentation pressures (PP and AP) and WPW. WPW represents the mechanical cost of the reflective waves returning from the periphery with the value increasing mainly due to the magnitude of AP. Subendocardial viability ratio (SEVR) represents the ratio of the diastolic pressure-time interval /systolic pressure-time interval. A SEVR < 100 represents impaired coronary flow reserve. Results: bSBP was observed to meet the HTN guidelines of ≥ 130 mmHg in 14/23 patients. In contrast, only 4/23 patients registered a cSBP ≥ 130 mmHg. Diastolic HTN was similar across the sample (85.0 ± 11.3 mmHg). The AP of 10.0 ± 6.8 mmHg with a range from 2.5 to 30.5 mmHg with 3 patients having an AP of 0 mmHg. WPW averaged 487.0 ± 13.0 with a range of 106 to 1670 and 3 patients did not register a WPW. Finally, SEVR averaged 105 ± 20.1% with 11 patients measuring below 100%. Conclusion: The results of this observational study provide several important findings. First, the OB population treated at CUHC presented with a bSPB greater than cSBP, suggesting that 14 patients could have been treated for HTN while only four patients presented with cSBP HTN. The AP value was low, as expected with few patients presenting with cSBP HTN. Surprisingly, the average SEVR of 105% included 11 patients below 100%. This has not been seen in previous similar studies. SEVR was not correlated with cSBP, suggesting another mechanism was responsible for the low SEVR value. WPW was low, as compared to other published work on patients presenting with cardiovascular disease. A larger study comparing normotensive to hypertension OB patients during and following the pregnancy is warranted. This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.