Peripheral blood pressure by Dinamap and central blood pressure by applanation tonometry in outpatient general practice

Abstract

Introduction: Central blood pressure (CBP) is the pressure exerted by the blood column at any given moment on the aortic and carotid artery walls, which is a close proxy for the blood pressure inside the brain and the heart, and is thus a better marker of cardiovascular morbidity and mortality than peripheral blood pressure (PBP).

Objective: To assess how the augmentation index (AI), peripheral pulse pressure (pPP), central pulse pressure (cPP) and subendocardial viability ratio (SEVR) vary in hypertensive patients according to level of control of CBP and PBP.

Methods: We performed an observational, cross-sectional study in a convenience sample from a general practice in Central Portugal over a period of four days in May 2010. Measurements were taken after a four-minute resting period. The following values were considered to reflect controlled pressures: PBP <140/90 mmHg, CBP <130/80 mmHg, pPP <55 mmHg and cPP <45 mmHg.

Results: The sample included 92 patients, 38 male (41.3%), mean age 62.3±11.1 years, with no significant difference in gender distribution. PBP was controlled in 55 (59.8%), and CBP in 53 (57.6%). Both PBP and CBP were controlled in 50 patients (54.3%) and neither was controlled in 34 (37.9%). pPP and cPP were significantly lower in those with controlled PBP (p<0.001) and CBP (p<0.001). AI was non-significantly lower in those with controlled PBP (78±9 vs. 80.7) and those with controlled CBP (78±9 vs.81±7) (p=0.02). SEVR was within the desirable range in 92 patients (92.2%). 78.4% of individuals were taking drugs acting on the renin angiotensin aldosterone system (RAAS).

Conclusions: In a convenience sample of 92 patients, PBP and CBP were controlled in 59.8% and 57.6%, respectively. Those with controlled PBP had significantly better peripheral systolic and diastolic blood pressure, CBP, pPP and cPP; the same was true of those with controlled CBP, who also had a significantly better AI. The percentage of the cardiac cycle in diastole had a desirable value for 92,2% of the subjects.

Keywords: Augmentation index; General practice/family medicine; Hipertensão arterial; Hypertension; Medicina Geral e Familiar; Peripheral pulse pressure: Central pulse pressure; Pressão arterial periférica: Pressão arterial central; Pressão de pulso; Pulse pressure; Razão de viabilidade subendocárdica; Subendocardial viability ratio; Índice de aumento.