Acetylsalicylic acid ( ASA ) did not reduce stroke or ‘ all cardiovascular events ’ compared to placebo in primary prevention patients with elevated BP and no prior cardiovascular disease .
To conclude for primary prevention in patients with elevated BP , antiplatelet therapy with ASA can not be recommended since the magnitude of benefit , a reduction in myocardial infa rct ion , is negated by a harm of similar magnitude , an increase in major haemorrhage .
Although elevated systemic blood pressure ( BP ) results in high intravascular pressure , the main complications of hypertension are related to thrombosis rather than haemorrhage .
It therefore seemed plausible that use of antithrombotic therapy may be useful in preventing thrombosis-related complications of elevated BP .
The objectives were to conduct a systematic review of the role of antiplatelet therapy and anticoagulation in patients with BP , to address the following hypotheses : ( i ) antiplatelet agents reduce total deaths and /or major thrombotic events when compared to placebo or other active treatment ; and ( ii ) oral anticoagulants reduce total deaths and /or major thromboembolic events when compared to placebo or other active treatment .
Influence of aspirin usage on blood pressure: dose and administration-time dependencies.
This study investigates the possible effects of acetylsalicylic acid ( ASA ; aspirin ) on systolic ( S ) and diastolic ( D ) blood pressure ( BP ) in healthy and mildly hypertensive subjects receiving ASA at different times according to their rest-activity cycle . A double-blind , r and omized , controlled trial was conducted in 73 healthy young adult volunteers and 18 previously untreated subjects with mild hypertension . The BP of each subject was automatically monitored every 30 minutes for 48h before the trial and at the end of a one-week course of placebo and a one-week course of ASA .  Healthy volunteers were r and omly assigned to one of six groups , defined according to the dose of ASA ( either 500 mg/day , the usual commercial dose ; or 100 mg/day ) and timing of ASA and placebo ( within 2h after awakening , Time 1 ; 7h to 9h after awakening , Time 2 ; or within 2h of bedtime , Time 3 ) . Subjects with mild hypertension received the low dose of 100 mg/day ASA , as well as one week of placebo , and were r and omly assigned to one of the same three groups defined above according to the time of treatment . A small ( approximately 2 mmHg in the 24h mean of SBP ) , but statistically significant , BP reduction was found when 500 mg/day ASA was given to healthy volunteers at Time 2 . With 100 mg/day , the effect of ASA in healthy subjects was comparable to the BP reduction found with the higher dose for Time 2 ; there was again no effect on BP at Time 1 , but we found a statistically significant effect at Time 3 ( 2.3 mmHg reduction in the 24h mean of SBP ) , larger than for Time 2 . For hypertensive patients , the BP reduction was again statistically significant for Time 2 and , to a greater extent , for Time 3 ( approximately 4.5 mmHg for both SBP and DBP ) ; all patients in these two groups showed a BP reduction after one week of ASA . The effect was about three times as large as the BP reduction obtained in healthy subjects treated with 100 mg/day ASA . Results indicate a statistically significant time- and dose-dependent effect of ASA on BP . In any meta- analysis of ASA effects , inquiries about the time when subjects took the drug are indicated and may account for discrepancies in the literature . Moreover , the influence of ASA on BP demonstrated here indicates the need to identify and control for ASA effects in patients using  ASA  before and during their participation in antihypertension medication trials
Acetylsalicylic acid ( ASA ) did not reduce stroke or ‘ all cardiovascular events ’ compared to placebo in primary prevention patients with elevated BP and no prior cardiovascular disease .
To conclude for primary prevention in patients with elevated BP , antiplatelet therapy with ASA can not be recommended since the magnitude of benefit , a reduction in myocardial infa rct ion , is negated by a harm of similar magnitude , an increase in major haemorrhage .
Although elevated systemic blood pressure ( BP ) results in high intravascular pressure , the main complications of hypertension are related to thrombosis rather than haemorrhage .
It therefore seemed plausible that use of antithrombotic therapy may be useful in preventing thrombosis-related complications of elevated BP .
The objectives were to conduct a systematic review of the role of antiplatelet therapy and anticoagulation in patients with BP , to address the following hypotheses : ( i ) antiplatelet agents reduce total deaths and /or major thrombotic events when compared to placebo or other active treatment ; and ( ii ) oral anticoagulants reduce total deaths and /or major thromboembolic events when compared to placebo or other active treatment .