Ideal Blood Pressure to Prevent Recurrent Stroke
Ideal Blood Pressure to Prevent Recurrent Stroke
Abstract & Commentary
By Michael H. Crawford, MD, Editor
Source: Ovbiagele B, et al. Level of systolic blood pressure within the normal range and risk of recurrent stroke. JAMA 2011;306:2137-2144.
The AHA/ASA 2011 guidelines on stroke prevention in those with a prior stroke or transient ischemic attack (TIA) recommend a blood pressure (BP) target of < 120/80 mmHg. However, the data to support this recommendation are sparse. Thus, these investigators performed a post hoc analysis of the Prevention Regimen for Effectively Avoiding Second Strokes (PRoFESS) to assess the risk of recurrent stroke with maintaining low normal BP as compared to higher BPs. This study included 20,330 patients who had had a nonembolic ischemic stroke within 120 days before randomization to four regimens: aspirin plus dipyridamole vs clopidogrel, or telmisartan vs placebo. The primary endpoint was recurrent stroke. The secondary endpoint was stroke, myocardial infarction (MI), or vascular mortality. Other treatment was at the primary physician's discretion and the mean follow-up was 2.5 years. There was no difference between the therapies in the two comparisons; so all the patients were included in this post hoc analysis of BP levels. The patients were divided into five systolic BP (SBP) groups: very low (< 120), low (120-129), high-normal (130-139), high (140-149), and very high (≥ 150). The primary endpoint was observed in 8% of the very low SBP patients; 7% of the low SBP groups; 7% of the high-normal group; 9% of the high group; and 14% of the very high patients. Compared to the high-normal group, the risk was higher in the very low group (adjusted hazard ratios [HRs] 1.29; 95% confidence interval, 1.07-1.56). Similar results were seen when the high and very high SBP groups were compared to the high normal group. The combined secondary endpoint followed a similar pattern. The authors concluded that in patients with a recent non-embolic ischemic stroke, the SBP associated with the lowest risk of recurrent stroke was 130-139 mmHg. SBPs higher or lower than this range were associated with a higher risk.
Commentary
This study defines a SBP sweet spot of 130-139 for preventing recurrent strokes based on adjusted HRs, but there is little penalty for pressures < 130 mmHg. Prior studies have suggested that there is no J curve for stroke prevention in hypertension treatment, but it is unclear how many patients in these studies had prior stroke. This study tends to confirm this perception, but does show a small increase in strokes at very low SBP levels. Thus, the patient with a prior stroke may not benefit from very low SBPs. This may be because they have cerebrovascular disease and need a somewhat higher perfusion pressure, but not usually above a SBP 140 mmHg.
There are several limitations to this study. It is not a randomized trial specifically targeted at the issue of SBP levels and recurrent stroke. The BP data were office based and performed by the primary doctor's staff. Recent studies have shown that research staff-generated BPs are more accurate than usual office BPs, as would be expected. Despite these limitations, aggressive BP lowering has not been proven to prevent recurrent stroke and the authors believe we should roll back our guidelines to < 140/90.
The AHA/ASA 2011 guidelines on stroke prevention in those with a prior stroke or transient ischemic attack (TIA) recommend a blood pressure (BP) target of < 120/80 mmHg. However, the data to support this recommendation are sparse.Subscribe Now for Access
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