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Does Intensive Blood Pressure Control Prevent Strokes?

Mar 23, 2019
 
Editor: Steve Freed, R.PH., CDE

Author: Dahlia Elimairi, Pharm D Student, UC Denver Skaggs School of Pharmacy

Maintaining a blood pressure below 130/80 mm Hg can eventually reduce the risk of having a repeat stroke, according to a recent study.

Hypertension is a major risk factor for both ischemic and hemorrhagic stroke. It is an identified risk factor in up to 90% of all strokes, and it is estimated that up to 40% of all strokes can be prevented with good blood pressure control. Higher blood pressures are associated with a higher risk of stroke, even in normotensive range. Blood pressure targets, in which maximal clinical benefit for stroke prevention, has not clearly defined.

 

A new randomized controlled trial and meta-analysis that was presented by Kazuo Kitagawa, of Women’s Medical University in Tokyo, Japan, at the international stroke conference 2019 in Honolulu has revealed that maintaining a blood pressure under 130/80 mm Hg may help reduce the risk of having a repeat stroke. The study was comprised of 2,454 patients, including patients from the RESPECT trial. The hazard ratio for the cumulative incidence of recurrent stroke with intensive versus standard blood pressure treatment was 0.78 (95% confidence interval (0.64 – 0.96; P = .016). The study is yet to be released.

In an interview with Elsevier’s Practice Update, Kitagawa stated “when the findings of the RESPECT study were pooled with previous randomized controlled trials, intensive blood pressure treatment was shown to be [effective] for secondary stroke prevention, compared with standard treatment. This is the most important finding.… After we published our results and updated meta-analysis, blood pressure control less than 130/80 mm Hg would be strongly recommended for secondary stroke prevention, as Grade A.”

In the PROGRESS trial, a randomized, placebo-controlled trial that established the beneficial effects of BP lowering in 6,105 patients with cerebrovascular disease, aimed to explore the likely optimum blood pressure level for patients with a history of cerebrovascular disease. The study was comprised of two series post hoc analyses. The first was designed to investigate the effects of randomized treatment on recurrent stroke by baseline BP levels, and the second was a corresponding observational analysis investigating the association between achieved follow-up BP levels and recurrent stroke risk.

The analyses of achieved follow-up blood pressure showed that the lowest risk of recurrence was among the one-quarter of participants with the lowest follow-up BP levels (median 112/72 mmHg), and that risks rose progressively with higher follow-up blood pressure levels. Minor side effects were progressively more common at lower blood pressure levels, but there was no excess of serious complications.

However, observational data reported that among patients aged 50 years or older, with previous non-cardio-embolic ischemic stroke, maintaining mean SBP level in the very low-normal (< 120mmHg) was associated with increased risk of recurrent stroke as compared with patients in the high-normal SBP group (130– 140 mmHg).

Maintaining a mean SBP between 120 and 130 mmHg was not associated with added benefit in the risk of recurrent stroke and came at the price of higher rate of secondary outcomes (composite of stroke, myocardial infarction or death from vascular causes)

In another large meta-analysis of randomized controlled trials that compared the impact of achieving tight versus usual systolic blood pressure control on stroke prevention, relative risk with 95% confidence interval was used as a measure of the association between an active treatment group with achieved SBP <130mmHg versus a comparator group with achieved SBP 130 to 139mmHg, and risk of stroke after pooling data across trials. The results showed that achieving a tight systolic blood level was associated with a lower stroke risk and a lower risk of major vascular events. In subgroup analyses, subjects with risk factors but no established cardiovascular disease showed substantial reduction of future stroke risk with tight control, but those with established cardiovascular disease at entry did not experience stroke risk reduction with tight control.

These studies support the recent study presented at the international stroke conference but still risk of side effects from intensive blood pressure lowering needs more investigation, especially in patients with cardiovascular disease and older age.

Practice Pearls:

  • Current evidence supports intensive blood pressure treatment (less than 130/80 mm Hg) for secondary stroke prevention.
  • Further research to study the effects of intensive blood pressure treatment in patients of older age and those with cardiovascular disease is warranted.
  • While side effects have been reported for intensive blood pressure treatment, there was no excess of serious complications. This still needs more investigation.

References:

https://www.practiceupdate.com/c/79848/32/2/?elsca1=emc_conf_ISC2019Post-2&elsca2=email&elsca3=practiceupdate_cardio&elsca4=201912_ISC2019Post-2&elsca5=conference&rid=OTE0MTIxOTE4NTkS1&lid=10332481

Lee M, Saver JL, Hong KS, Hao Q, Ovbiagele B. Does achieving an intensive versus usual blood pressure level prevent stroke? Ann Neurol. 2012 Jan;71(1):133-40.

Yannoutsos A, Dreyfuss Tubiana C, Safar ME, Blacher J. Optimal blood pressure target in stroke prevention. Curr Opin Neurol. 2017 Feb;30(1):8-14.

Arima H, Chalmers J, Woodward M, Anderson C, Rodgers A, Davis S, Macmahon S,Neal B; PROGRESS Collaborative Group. Lower target blood pressures are safe and effective for the prevention of recurrent stroke: the PROGRESS trial. J Hypertens. 2006 Jun;24(6):1201-8.

Dahlia Elimairi, Pharm D student, UC Denver Skaggs School of Pharmacy