Hemodynamic differences between women and men with elevated blood pressure in China: A non-invasive assessment of 45,082 adults using impedance cardiography.

BACKGROUND: Whether there are sex differences in hemodynamic profiles among people with elevated blood pressure is not well understood and could guide personalization of treatment. METHODS AND RESULTS: We described the clinical and hemodynamic characteristics of adults with elevated blood pressure in China using impedance cardiography. We included 45,082 individuals with elevated blood pressure (defined as systolic blood pressure of ≥130 mmHg or a diastolic blood pressure of ≥80 mmHg), of which 35.2% were women. Overall, women had a higher mean systolic blood pressure than men (139.0 [±15.7] mmHg vs 136.8 [±13.8] mmHg, P<0.001), but a lower mean diastolic blood pressure (82.6 [±9.0] mmHg vs 85.6 [±8.9] mmHg, P<0.001). After adjusting for age, region, and body mass index, women <50 years old had lower systemic vascular resistance index (beta-coefficient [ß] -31.7; 95% CI: -51.2, -12.2) and higher cardiac index (ß 0.07; 95% CI: 0.04, 0.09) than men of their same age group, whereas among those ≥50 years old women had higher systemic vascular resistance index (ß 120.4; 95% CI: 102.4, 138.5) but lower cardiac index (ß -0.15; 95% CI: -0.16, -0.13). Results were consistent with a propensity score matching sensitivity analysis, although the magnitude of the SVRI difference was lower and non-significant. However, there was substantial overlap between women and men in the distribution plots of these variables, with overlapping areas ranging from 78% to 88%. CONCLUSIONS: Our findings indicate that there are sex differences in hypertension phenotype, but that sex alone is insufficient to infer an individual's profile.

Effectiveness of an impedance cardiography guided treatment strategy to improve blood pressure control in a real-world setting: results from a pragmatic clinical trial.

OBJECTIVE: To test the effectiveness of an impedance cardiography (ICG) guided treatment strategy on improving blood pressure (BP) control in real-world clinical practice. DESIGN: A single-centre, pragmatic randomised trial. SETTING: A hypertension clinic of the Peking University People's Hospital in Beijing, China. PARTICIPANTS: Adults who sought outpatient care for hypertension in the hypertension clinic at the Peking University People's Hospital between June and December 2019. INTERVENTIONS: A computerised clinical decision support of recommending treatment choices to providers based on patients' haemodynamic profiles measured by ICG. MAIN OUTCOME MEASURES: Changes in systolic BP (SBP) and diastolic BP (DBP) levels at the follow-up visit 4-12 weeks after baseline. Secondary outcomes included achievement of BP goal of <140/90 mm Hg and the changes in BP by baseline BP, age, sex and body mass index (BMI). RESULTS: A total of 102 adults (mean age was 54±14 years; 41% were women) completed the study. The mean baseline SBP was 150.9 (SD of 11.5) mm Hg and mean baseline DBP was 91.1 (11.3) mm Hg. At the follow-up visit, the mean SBP and DBP decreased by 19.9 and 11.3 mm Hg in the haemodynamic group, as compared with 12.0 and 4.9 mm Hg in the standard care group (p value for difference between groups <0.001). The proportion of patients achieving BP goal of <140/90 mm Hg in the haemodynamic group was 67%, as compared with 41% in the standard care group (p=0.017). The haemodynamic group had a larger effect on BP reduction consistently across subgroups by age, sex, BMI and baseline BP. CONCLUSIONS: An ICG-guided treatment strategy led to greater reductions in BP levels than were observed with standard care in a real-world population of outpatients with hypertension. There is a need for further validation of this strategy for improving blood pressure treatment selection. TRIAL REGISTRATION NUMBER: NCT04715698.

Relationship of Age With the Hemodynamic Parameters in Individuals With Elevated Blood Pressure.

BACKGROUND: Age is known to be associated with the prevalence and pathophysiology of hypertension. However, there is little information on whether age stands as a good proxy for the specific hemodynamic profile of an individual with elevated blood pressure (BP), which could be important in the selection of therapy. DESIGN: This is a cross-sectional study. SETTING: People who underwent a noninvasive, hemodynamic assessment using impedance cardiography at 51 sites of iKang Health Checkup Centers throughout China between January 2012 and October 2018. PARTICIPANTS: We included 116,851 individuals, aged 20 to 80 years. MAIN OUTCOMES AND MEASURES: Relationship between age and hemodynamic parameters (cardiac index, systemic vascular resistance index [SVRI]), among individuals with elevated BP (systolic BP ≥130 mm Hg or diastolic BP ≥80 mm Hg). RESULTS: Final study population included 45,082 individuals with elevated BP: 29,194 men and 15,888 women with a mean (±SD) age of 48 (±13) and 54 (±12) years, respectively. Cardiac index was negatively associated with age with an adjusted, per decade decrease of 0.17 (95% confidence interval [CI] = 0.17-0.18) L/min/m2 in men and 0.24 (95% CI = 0.23-0.25) L/min/m2 in women. SVRI was positively associated with age with an adjusted, per-decade increase of 174.2 (95% CI = 168.8-179.7) dynes·s·cm-5 ·m2 in men and 214.1 (95% CI = 204.3-223.8) dynes·s·cm-5 ·m2 in women. However, there was substantial overlap in the distribution of these parameters across different age groups in both sexes. CONCLUSIONS: In this large study, we observed that cardiac index decreased and SVRI increased with age among individuals with elevated BP. Even though there was a general trend with age, we observed heterogeneity within age strata, suggesting that age alone is inadequate to indicate the hemodynamic profile for an individual. J Am Geriatr Soc 68:1520-1528, 2020.

Hemodynamic Phenotypes of Hypertension Based on Cardiac Output and Systemic Vascular Resistance.

BACKGROUND: Blood pressure is a physiologic measure that reflects cardiac output and systemic vascular resistance. Classification by these components could be useful in characterizing subtypes of hypertension, which may have a role in selecting treatment strategies. However, hemodynamic phenotypes of a large, stable, outpatient population with hypertension remain unknown. METHODS: We included 34,238 people with systolic blood pressure of ≥130 mm Hg, who underwent impedance cardiography at 51 sites of iKang Health Checkup Centers throughout China between 2012 and 2018. Hemodynamic parameters measured included stroke volume, stroke volume index, heart rate, cardiac output, cardiac index, systemic vascular resistance, and systemic vascular resistance index. We characterized these by systolic blood pressure categories and assessed patient characteristics associated with the ratio of cardiac index to systemic vascular resistance index. RESULTS: Among the study cohort (n = 33,414; mean age 52 ± 13 years; 36.6% female), 49%, 40%, and 11% had systolic blood pressure130-139, 140-159, and ≥160 mm Hg, respectively. Among patients with systolic blood pressure 140-159 mm Hg, 9353 (70%) had high systemic vascular resistance index but normal/low cardiac index, 1949 (15%) had high cardiac index but low/normal systemic vascular resistance index, and 2053 (15%) had low/normal cardiac index and systemic vascular resistance index. Using multivariable analysis, we found that cardiac index to systemic vascular resistance index ratio was negatively associated with age and body mass index (all P <0.05; R-square 0.16, 0.12, and 0.09 for systolic blood pressure 130-139, 140-159 and ≥160 mm Hg, respectively). CONCLUSIONS: Different hemodynamic blood pressure phenotypes were identified across all hypertensive blood pressure categories. Although individual characteristics were associated with the cardiac index to systemic vascular resistance index ratio, they only weakly explained the variation.