What is the Healthiest Systolic Blood Pressure Range for Patients After an Ischemic Stroke?

Abstract & Commentary

By Joseph E. Scherger, MD, MPH, Vice President, Primary Care, Eisenhower Medical Center, Clinical Professor, Keck School of Medicine, University of Southern California. Dr. Scherger reports no financial relationships relevant to this field of study.

Synopsis: A post-stroke analysis of more than 20,000 patients in 35 countries showed that the lowest risk systolic blood pressure (BP) range is 130-139 mmHg. There is a J-shaped curve of risk with an increase in recurrent stroke among patients with a systolic BP below 120 mmHg and above 140 mmHg.

Source: Ovbiagele B, et al. Level of systolic blood pressure within the normal range and risk of recurrent stroke. JAMA 2011;306:2137-2144.

A randomized controlled trial enrolled 20,330 patients in 35 countries after a non-cardioembolic ischemic stroke to look at the effectiveness of different treatment regimens. The results of the Prevention Regimen for Effectively Avoiding Second Strokes (PRoFESS) trial were published in 2008.1,2 The trial looked at two antithrombotic regimens (a fixed-dose combination of aspirin with extended-release dipyridamole and clopidogrel) and telmisartan vs placebo. The outcome of the trial was no difference between the two antithrombotic regimens and no difference between telmisartan and placebo in preventing a second stroke. The mean follow-up period was 2.44 years.

This study is a post hoc observational analysis of all the patients combined as to the rate of recurrent stroke depending on the systolic BP range. The study also looked at a composite of stroke, myocardial infarction, or death from vascular causes. The patients were divided into five groups based on the mean systolic BP level: very low-normal (less than 120 mmHg), low-normal (120-129 mmHg), high-normal (130-139 mmHg), high (140-149 mmHg), and very high (greater than 150 mmHg).

The rate of recurrent stroke was 8% in the very low-normal systolic BP group, 7.2% in the low-normal systolic BP group, 6.8% in the high-normal systolic BP group, 8.7% in the high systolic BP group, and 14.1% in the very high systolic BP group. Similar findings were seen in the secondary analysis of a composite of stroke, myocardial infarction, or death from vascular causes.

Commentary

This study confirms a J-shaped curve of risk for systolic BP in patients after an ischemic stroke. While having a high systolic BP over 140 mmHg carries the greatest risk, a systolic BP of less than 120 mmHg is of greater risk than between 120 and 140 mmHg. Interestingly, 130-139 mmHg appears to be the safest range.

Other studies of BP control in different conditions have had inconsistent results, with some showing a J-shaped curve of risk and others not.3-5 These authors believe that the timing of the studies relative to the time of the first stroke is very important. In this trial, patients were enrolled soon after the first stroke, with almost 40% randomized within 10 days of the index event. This study showed that the greatest risk for recurrent stroke is 3 to 6 months after the previous stroke. Other trials not showing a J-shaped curve of risk enrolled most of their patients more than 1 year and even 5 years after their index event.6,7

Blood pressure guidelines are being rewritten to highlight the risk of overtreatment. Unfortunately, we have lived through a period where going as low as possible became the norm and systolic BP above 130 was even regarded as "prehypertension." We already know that low BPs (below 110 mmHg) are dangerous in the elderly. The mean age in this study was 66.1 years and we see that systolic BPs below 120 increase the risk of recurrent stroke. The fact that the 130-139 range was even safer than the 120-129 range should give us pause and alert us that getting below 140 mmHg is the proper treatment goal in treating BP, at least in patients with a previous ischemic stroke, the outcome most associated with high BP.

References

1. Yusuf S, et al. Telmisartan to prevent recurrent stroke and cardiovascular events. N Engl J Med 2008;359: 1225-1237.

2. Sacco RL, et al. Aspirin and extended-release dipyridamole versus clopidogrel for recurrent stroke. N Engl J Med 2008;359:1238-1251.

3. Cushman WC, et al. Effects of intensive blood pressure control in type 2 diabetes mellitus. N Engl J Med 2010;362:1575-1585.

4. Cooper-DeHoff RM, et al. Tight blood pressure control and cardiovascular outcomes among hypertensive patients with diabetes and coronary artery disease. JAMA 2010;304:61-68.

5. Messerli GH, et al. Dogma disputed: Can aggressively lowering blood pressure in hypertensive patients with coronary artery disease be dangerous? Ann Intern Med 2006;144:884-893.

6. Arima H, et al. Lower target blood pressures are safe and effective for the prevention of recurrent stroke: The PROGRESS trial. J Hypertens 2006;24:1201-1208.

7. Sleight P, et al. Prognostic value of blood pressure in patients with high vascular risk in the Ongoing Telmisartan Alone and in combination with Ramipril Global Endpoint Trial study. J Hypertens 2009;27:1360-1369.