Abstract P206: Interarm Difference in Blood Pressure: Prevalence, Risk Factors, and Relevance for Diagnosis of Disease of the Aorta Among Patients Referred to Specialized Regional Hypertension Center

Abstract

Background: Initial evaluation of hypertension (HTN) should include assessment of blood pressure (BP) in both arms. The prevalence of high interarm differ ranges from 3% in the general adult population to about 10% in the patients with HTN. However, we lack proper estimates of its prevalence, and existing practice of follow up for these patients in a referred population. Methods: We performed a retrospective chart review of all prevalent patients followed at the Hypertension Center at the Ottawa Hospital. BP data from the first visit were used for assessment for interarm BP difference. We considered interarm difference in either systolic or diastolic BP in excess of 10 mmHg for casual BP by mercury sphygmomanometry to be clinically significant. Results: 493 patients of 580 patients were included in this study based on available data. The prevalence of clinically significant interarm difference in systolic or diastolic BP was 16.2% and was similar among men and women. These patients were more likely to be smokers (current or previous; 53.5% vs 36.8%) with peripheral arterial disease (PAD, 15% vs 8%). None of these patients had undergone further investigations of ascending aorta/aortic arch. Conclusions: A significant proportion of referred patients have a high interarm difference in systolic or diastolic BP. No clinical investigations were ordered to evaluate for ascending aorta/aortic arch disease reflecting the physicians’ lack of understanding of its clinical relevance. The association with smoking and PAD suggests underlying aortic/large vessel disease as a potential mechanism in some patients.