The Effect of Transdermal Glyceryl Trinitrate on 24 h Ambulatory Blood Pressure in Acute/Subacute Stroke

Abstract

Background High blood pressure is a common complication in acute stroke and is associated with a poor outcome. Aims This study assesses the effects of transdermal glyceryl trinitrate on 24 h ambulatory blood pressure in patients with recent stroke. Methods One hundred and seven patients with acute ischaemic or haemorrhagic stroke were included. The patients had been enrolled in one of two trials of transdermal glyceryl trinitrate (5 mg daily) or placebo/control, and underwent 24 h ambulatory blood pressure monitoring (56 glyceryl trinitrate, 51 control). Ambulatory blood pressure data were analysed using area under the curve for the entire 24 h, and day and night periods. Nocturnal dipping was defined as a decline in systolic blood pressure >10%. Comparisons of blood pressure between groups were performed by analysis of covariance (ANCOVA) with adjustments for trial and baseline measure. Results In comparison with control, glyceryl trinitrate significantly lowered 24 h blood pressure (systolic blood pressure/ diastolic blood pressure 9·4/4·8 mmHg, P < 0·001/0·001, n = 104), daytime blood pressure (8·7/4·2, P < 0·001/ < 0·001, n = 103) and night-time blood pressure (6·9/1·7, P = 0·008/0·458, n = 86). Only 86 patients (glyceryl trinitrate 45, placebo/control 41) had sufficient night blood pressure measurements to assign dipping status; 28 were dippers (12 glyceryl trinitrate, 16 control) and 58 were nondippers (33 glyceryl trinitrate, 25 control); glyceryl trinitrate significantly lowered systolic but not diastolic blood pressure in both dippers and nondippers. Treatment with glyceryl trinitrate increased the daytime heart rate (4·8 beats/min) but not the night-time heart rate. Patients whose blood pressure did not dip at night had a worse functional outcome at three-months. Conclusions Transdermal glyceryl trinitrate (5 mg) significantly lowered 24 h blood pressure by 9/5 mmHg (equivalent to a 6% reduction) in both dipping and nondipping patients with acute/subacute stroke. This reduction in blood pressure is clinically relevant and is unlikely to be excessive.