What is the goal systolic blood pressure SBP following a stroke?

Blood Pressure and Stroke Prevention Evidence Tables and Reference List

Stroke Risk and Hypertension

Hypertension is widely regarded as the most important modifiable risk factor for stroke. Results from phases 1 and 2 of the INTERSTROKE study (O’Donnell et al. 2010, O’Donnell et al. 2016), indicated that among the five risk factors that accounted for more than 80% of the risk for stroke, hypertension was found to be most significant. The others included current smoking, abdominal obesity, diet, and physical activity. In phase 1 of the study, a self-reported history of hypertension or measured blood pressure ≥160/90 mm Hg was associated with an increased risk of all stroke (OR=2.98, 99% CI 2.72-3.28), but was highest for hemorrhagic stroke (OR=9.18, 99% CI 6.80-12.39). The same risk pattern was reported in phase 2 of the study, which used a self-reported history of hypertension or measured blood pressure ≥140/90 mm Hg to define hypertension (O’Donnell et al. 2016). The risk of hemorrhagic stroke was significantly increased (OR=4.09, 99% CI 3.51-4.77). In another case-control study, Du et al. (2000) reported the risk of stroke was significantly higher among subjects who were hypertensive (OR=2.45, 95% CI 1.62 to 3.71, p< 0.001) and the risk of stroke increased with additional risk factors including smoking and diabetes. The authors suggested that at least three-quarters of strokes in hypertensive patients are preventable given appropriate treatment. The authors further emphasized that strokes are caused not by a single risk factor, but by the interaction of multiple risk factors, with some having a stronger independent relationship with stroke than others.  A meta-analysis (Lewington et al. 2002) that included the results of one million adults from 61 prospective studies found that an increase of 20 mm Hg in systolic and 10 mm Hg in diastolic blood pressure led to a two-fold increase in stroke mortality in persons aged 40 – 69 years, without any evidence of a threshold down to at least 115/75 mm Hg for all vascular deaths. Age-specific associations were found to be similar for men and women, and for cerebral hemorrhage and cerebral ischemia.   Data from 1.25 million people without a history of cardiovascular disease, included in the CALIBER database were used to estimate lifetime risks and years of life lost to cardiovascular disease (Rapsomanki et al. 2014). During a median follow-up of 5.2 years, for each 20/10 mm Hg increase, the risks of transient ischemic attack, ischemic stroke and ICH increased across age cohorts (30-59, 60-79 and ≥80 years), with the highest risks noted in the youngest patients. The lifetime risk of ischemic stroke (from index age of 30 years) in persons with hypertension, defined as ≥140/90 mm Hg, was 7.6% (95% CI 7.3%-7.8%) compared with 6.5% (95% CI 6.2%-6.9%) for persons without hypertension. The years of life lost to ischemic stroke for those with hypertension was approximately a half a year.

Pharmacological Treatment of Hypertension Reduces Stroke Risk

Among persons who sustained an acute stroke, antihypertensive treatment, initiated within 48 hours of the event was shown to significantly reduce the risk of recurrent stroke at >12 months, compared with placebo or no treatment (RR=0.81, 95% CI 0.70-0.93). The effect was most pronounced for persons with baseline SBP>140 mm Hg. ACE inhibitors and diuretics were found to be the most effective antihypertensive agents (Zonneveld et al. 2018). The risks of recurrent stroke, disabling or fatal stroke and cardiovascular death were all significantly reduced following antihypertensive treatment compared with placebo in a systematic review including 14 RCTs (Katsanos et al. 2017). In meta-regression analysis, increasingly lower SBP was linearly associated with significant reductions in recurrent stroke, MI, death from any cause and cardiovascular death. Several meta-analyses included trials with persons both with and without previous stroke. Intensive blood pressure treatment was shown to decrease the risk of recurrent stroke compared with less intensive treatment by 22% (HR=0·78, 95% CI 0·67–0·90, p=0·001), after a mean duration of follow-up of 3.8 years (Xie et al. 2016, n=19 trials). Bangalore et al. (2017) included trials comparing different goal systolic blood pressure (SBP) targets (<150, <140, <130 and <120 mm Hg) against a reference standard of <160 mm Hg. The risk of stroke was decreased in a comparison of target SBP <120 vs. <160 mm Hg, the reference standard (RR=0.54, 95% CI 0.29-1.00), but there were no significant reductions in risk for any of the other pairings (<150 vs. <160 mm Hg; <140 vs. <160 mm Hg; <130 vs. <160 mm Hg). Looking from a different perspective, compared with a target SBP of <120 mm Hg, the risk of stroke was significantly increased with SBP <140 mm Hg (RR=1.72, 95% CI 1.42-2.58), <150 mm Hg (RR=1.97, 95% CI 1.26-3.08) and <160 mm Hg (RR=3.27, 95% CI 1.78-6.00). The authors suggested that SBP targets of <120 and <130 mm Hg were best for stroke prevention. Ettehad et al. (2016) included the results of 123 RCTs examining persons with and without previous stroke or transient ischemic attack. The risk of major cardiovascular events was reduced significantly for each 10 mm Hg reduction in SBP (RR= 0·80, 95% CI 0·77–0·83), including stroke (RR=0·73, 95% CI 0·68–0·77), with the magnitude of risk reduction proportional to the blood pressure reduction achieved. The risk of stroke was reduced significantly per each 10 mm Hg decrease in SBP with antihypertensive treatment in persons with and without existing cardiovascular disease (RR=0·74, 95% CI 0.67-0.81 and RR=0·75, 95% CI 0.63-0.89, respectively). The most effective antihypertensive agents for the reduction in stroke risk were angiotensin receptor blockers and calcium channel blockers. Beta-blockers were inferior to other classes of antihypertensives. The risk of stroke was reduced with antihypertensive treatment across different 10 mm Hg strata of baseline SBP ≥130. Lee et al. (2012) included the results of 11 RCTs representing data from 42,572 participants (794 with previous stroke) who were at high risk for cardiovascular disease and compared treatment of tight blood pressure control (SBP <130 mm Hg) with usual control (SBP 130 to 139 mm Hg) on subsequent stroke risk.  Tight SBP target was associated with reduced risks of future stroke, and major vascular events, and major coronary events, but was not associated with a significantly lower risk of death. Among patients with diabetes, those without a history of CVD, and younger than 65 years experienced the greatest stroke risk reduction. 

A recent clinical trial (RESPECT) compared standard blood pressure treatment, with a target of <140/90mm Hg, with intensive treatment target of <120/80 mm Hg, among 1,280 patients with a stroke sustained within the previous 30 days to 3 years with a baseline SBP of 130 to 180 mm Hg or DBP of 80 to 110 mm Hg. Unfortunately, the trial was stopped prematurely, before planned recruitment of 2,000 participants (Kitagawa et al. 2019). After a mean duration of follow-up of 3.8 years, there were 52 strokes (2.26% per year) in the standard group and 39 (1.65% per year) in the intensive group.  The risk of recurrent stroke was not reduced significantly with intensive BP treatment (HR=0.73, 95% CI 0.49-1.11, p=0.15). The Secondary Prevention of Small Subcortical Strokes (SPS3 Trial) examined the effectiveness of medical management to reduce recurrent stroke in persons with a lacunar stroke, sustained within the previous 180 days. Lowering systolic blood pressure (SBP) to a target of < 130 mm Hg resulted in a non-significant reduction on all stroke, disabling stroke, myocardial infarction and vascular death compared with target SBP levels of 130-149 mm Hg (Benavente et al. 2013). 

Lower blood pressure targets (<130/80 mm Hg) have been recommended for persons with diabetes for the prevention of first or recurrent stroke. A Cochrane review (Arguedas et al. 2013) included the results from 5 RCTs comparing ‘lower’ blood pressure targets (any target <130/85mm Hg) with ’standard’ targets (<140-160/90-100 mm Hg). Participants were adults with type 2 diabetes and elevated blood pressure, or already receiving treatment for elevated blood pressure. In the single included trial, which aimed at reductions in systolic blood pressure (ACCORD 2010) intensive BP control was not associated with reductions in total mortality (RR= 1.05, 95% CI 0.84-1.30) but was associated with reduction in the risk of stroke (RR=0.58, 95% CI 0.39 to 0.88, p= 0.009); however, serious adverse events, attributed to therapy occurred more often in patients in the intensive group (3.3% vs. 1.3%, p<0.001). In the 4 trials aimed at reductions in diastolic blood pressure, intensive BP control was not associated with reductions in total mortality (RR= 0.73, 95% CI 0.53-1.01, p=0.054) or stroke (RR= 0.67, 95% CI 0.42-1.05, p=0.077). In the UKPDS (Turner et al. 1988), the risk of fatal and nonfatal stroke (combined) was reduced by 44% (HR= RR=0.56, 95% CI 0.35-0.89, p=0.013) among patients in the tight BP control (mean BP achieved 144/82 mm Hg) compared with less aggressive control (mean BP achieved 154/87 mm Hg).

Sex and Gender Considerations

The evidence is conflicting regarding the increased risk of ischemic stroke associated with hypertension according to sex. There was no indication to suggest a sex difference in the relationship between systolic blood pressure (SBP) and the risk of stroke in a large meta-analysis including 124 studies (Peters et al. 2013) or from the CALIBER study including over 1.25 million persons (Rapsomaniki et al. 2014). In one of the REGARDS publications (Madsen et al. 2019), which included data from 26,461 participants, the risk of stroke was increased significantly more per each 10 mm Hg increase in SBP in women (HR=1.15, 95% CI, 1.10–1.20 vs. HR=1.08, 95% CI, 1.03–1.14, p for interaction=0.09). 

Control of hypertension was found to be significantly higher among women <60 years compared with men (56.3% vs. 50.6%); but was lower among women aged ≥60 years (50.8% for women vs. 54.6% for men, p<0.05) (Yoon et al. 2015). Although not statistically significant, intensive blood pressure lowering was found to reduce the risk of major cardiovascular events, including stroke, more in men compared with women in a sub analysis of the SPRINT trial (HR=0.84, 95% CI 0.61–1.13 vs. HR=0.73, 95% CI 0.59–0.89, p value for interaction=0.45) (Foy et al. 2018).