Sandset EC, Jusufovic M, Sandset PM, Bath PMW, and Berge E, on behalf of the SCAST Study Group. Effects of Blood Pressure–Lowering Treatment in Different Subtypes of Acute Ischemic Stroke. Stroke. 2015
Goals of blood pressure has been a hot topic in hemorrhagic strokes. The INTERACT trials have confirmed with evidence, that it is safe to lower blood pressure acutely in patients with intracerebral hemorrhages. The question of what blood pressure goals should be during acute ischemic strokes remains a question. While it is intuitive that permissive hypertension is beneficial for patients, there has never been any clear data to suggest what the actual goals should be. Additionally, as intuitive as it seems to increase perfusion by allowing for permissive hypertension, is there truly a benefit with permissive hypertension? The Scandinavian Candesartan Acute Stroke Trial (SCAST) done prior did not show benefit with regards to blood pressure lowering with candesartan in acute stroke. Sanset et al attempt to re-evaluate this same data to see if there is difference in outcome when looking at different stroke subtypes.
The data was generated from the original SCAST trial which was a randomized, placebo controlled trial including 2029 patients presenting within 30 hours of ischemic or hemorrhagic stroke with systolic blood pressure greater than 140 mmHg. Acute ischemic stroke (AIS) subtype was determined using the Oxfordshire Community Stroke Project (OCSP) classification.
Results included 1733 patients with AIS. There was a trend towards better effect (mRS 0-2) of candesartan in patients with larger infarcts (Total anterior Circulation + Partial anterior circulation) than in patients with smaller infarcts (Lacunar Infarction). This is unfortunately only a trend, as confidence intervals for all stroke subtypes cross 1.0. Lastly, A composite vascular end point consisting of vascular death, myocardial infarction or stroke during the first 6 months did not show any difference between the two groups.
One thought to ponder (as this study insinuates) is that small vessel infarct patients may be harmed with acute blood pressure lowering. This is thought to be secondary to baseline elevated blood pressures which would be too low with goals such as <140 systolic. It is worthwhile to note that OCSP categories of “total anterior circulation,” “partial anterior circulation,” “posterior circulation,” and “lacunar infarct” were used. An actual measurement of infarct volume may have been more useful, although this parameter is not likely available due to using data from a prior study. Additionally, using TOAST category stroke subtypes may have been more useful in the clinical setting as TOAST imparts clinical relevance more so than the OCSP does. Ultimately this study shows that there was only a trend towards better effect of candesartan in patients with larger infarcts. I would argue however, it is not necessarily a function of infarct volume, rather it may be due to the mechanism of stroke, ie…large vessel infarct vs. lacunar infarct. In either case, this notion needs further studies to truly support such a notion.