Shiwani Mahajan1, Jianlei Gu2, Yuan Lu3, Rohan Khera4, Erica S Spatz1, MaoZhen Zhang5, NingLing Sun6, Xin Zheng7, Hongyu Zhao8, Hui Lu9, Zheng J Ma10, Harlan M Krumholz11. 1. Center for Outcomes Research and Evaluation, Yale-New Haven Hospital, New Haven, Conn; Section of Cardiovascular Medicine, Department of Internal Medicine, Yale School of Medicine, New Haven, Conn. 2. SJTU-Yale Joint Center for Biostatistics, School of Life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai, China; Shanghai Engineering Research Center for Big Data in Pediatric Precision Medicine, Shanghai, China. 3. Center for Outcomes Research and Evaluation, Yale-New Haven Hospital, New Haven, Conn. 4. Division of Cardiology, University of Texas Southwestern Medical Center, Dallas, Tex. 5. iKang Healthcare Group, Inc., Shanghai, China; Department of Cardiology, Xinhua Hospital Affiliated with Shanghai Jiao Tong University School of Medicine, Shanghai, China. 6. Department of Hypertension at Heart Center, People's Hospital, Peking University, Beijing, China. 7. National Clinical Research Center of Cardiovascular Diseases, State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China. 8. SJTU-Yale Joint Center for Biostatistics, School of Life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai, China; Department of Biostatistics, School of Public Health, Yale University, New Haven, Conn. 9. SJTU-Yale Joint Center for Biostatistics, School of Life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai, China; Center for Biomedical Informatics, Shanghai Children's Hospital, Shanghai, China. 10. SJTU-Yale Joint Center for Biostatistics, School of Life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai, China; Department of Biostatistics, School of Public Health, Yale University, New Haven, Conn; Beijing Li-Heng Medical Technologies, Ltd, Beijing, China. 11. Center for Outcomes Research and Evaluation, Yale-New Haven Hospital, New Haven, Conn; Section of Cardiovascular Medicine, Department of Internal Medicine, Yale School of Medicine, New Haven, Conn; Department of Health Policy and Management, Yale School of Public Health, New Haven, Conn. Electronic address: harlan.krumholz@yale.edu.
Abstract
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.
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.