Cardiac Remodeling After Hypertensive Pregnancy Following Physician-Optimized Blood Pressure Self-Management: The POP-HT Randomized Clinical Trial Imaging Sub-study.

<b>Background:</b> Hypertensive pregnancy disorders are associated with adverse cardiac remodeling, which can fail to reverse postpartum in some women. The Physician Optimized Postpartum Hypertension Treatment trial demonstrated improved blood pressure control, while the cardiovascular system recovers postpartum, associates with persistently reduced blood pressure. We now report the impact on cardiac remodeling. <b>Methods:</b> In this prospective, randomized, open-label, blinded endpoint trial, in a single UK hospital, 220 women were randomly assigned 1:1 to self-monitoring with research physician-optimized antihypertensive titration, or usual postnatal care from primary care physician and midwife. Participants were aged 18 years or over, with pre-eclampsia or gestational hypertension, requiring antihypertensives on hospital discharge postnatally. Pre-specified secondary cardiac imaging outcomes were recorded by echocardiography around delivery, and again at blood pressure primary outcome assessment, around nine months postpartum, when cardiovascular magnetic resonance was also performed. <b>Results:</b> 187 women (101 intervention; 86 usual care) underwent echocardiography at baseline and follow up, at a mean 258+/-14.6 days postpartum, of which 174 (93 intervention; 81 usual care) also had cardiovascular magnetic resonance at follow up. Relative wall thickness by echocardiography was 0.06 (95% CI0.07 to 0.05, P=<0.001) lower in the intervention group between baseline and follow up, and cardiovascular magnetic resonance at follow up demonstrated a lower left ventricular mass (-6.37g/m² (95% CI -7.99 to -4.74, P<0.001), end diastolic volume (-3.87ml/m², 95% CI -6.77 to -0.98, P=0.009) and end systolic volume (-3.25ml/m², 95% CI 4.87 to -1.63, P <0.001) and higher left and right ventricular ejection fraction by 2.6% (95% CI 1.3 to 3.9, P<0.001) and 2.8% (95% CI 1.4 to 4.1, P<0.001) respectively. Echocardiography assessed left ventricular diastolic function demonstrated a mean difference in average E/E' of 0.52 (95% CI -0.97 to -0.07, P=0.024), and a reduction in left atrial volumes of -4.33ml/m² (95% CI -5.52 to -3.21, P=<0.001) between baseline and follow up, when adjusted for baseline differences in measures. <b>Conclusions:</b> Short-term postnatal optimization of blood pressure control following hypertensive pregnancy, through self-monitoring and physician-guided antihypertensive titration, associates with long term changes in cardiovascular structure and function, in a pattern associated with more favorable cardiovascular outcomes.