Acute BP reduction of no benefit to stroke patients
MedWire News: Early reduction of high blood pressure (BP) in patients with acute stroke does not benefit them and may even be harmful, show the findings of SCAST.
Acute BP reduction did not affect cardiovascular outcomes and mortality but showed a tendency to worsen patients' functional outcomes, the researchers reported at the International Stroke Conference in Los Angeles, California, USA. The findings are also published in The Lancet.
"To force blood pressure reduction on a patient who has high blood pressure seems to be harmful," lead investigator Eivind Berge (Oslo University Hospital Ullevål, Norway) told MedWire News.
"The reason is probably that, by lowering BP, you also lower cerebral blood perfusion, which may be critically low in areas of the brain that are damaged by a stroke."
Conversely, high BP is thought to contribute to cerebral edema or hemorrhage in stroke patients and has been linked to poor outcomes in previous trials. Indeed, the results of the Acute Candesartan Cilexetil Therapy in Stroke Survivors (ACCESS) trial, which included 342 acute stroke patients with high BP, suggested that acute BP reduction could be beneficial.
SCAST (Scandinavian Candesartan Acute Stroke Trial) was a much larger study, including 2029 stroke patients (~85% ischemic stroke) who were randomly assigned to receive candesartan starting at 4 mg on day 1 and rising to 16 mg on days 3-7, or placebo.
The patients' average BP was 171/90 mmHg at enrollment, which took place within 30 hours of symptom onset. By day 7, this fell to 147/82 mmHg in the candesartan group versus 152/84 mm Hg in the placebo group - a significant difference.
The first of two co-primary endpoints was the composite of vascular death, myocardial infarction, or stroke during the first 6 months. There were 120 such events in the candesartan group and 111 in the placebo group, which did not amount to a significant difference.
But for the second endpoint of functional outcome on the modified Rankin Scale (mRS) at 6 months, Berge reported a "consistent drift" toward worse outcomes in the candesartan group. Patients were 17% more likely to have poorer outcomes on the mRS if they received active rather than placebo treatment, with a 95% confidence interval of 1.00-1.38 and a p value of 0·048. This was not statistically significant, however, because the co-primary endpoint trial design required a p value of 0·025 or less.
Secondary endpoints were unaffected by treatment allocation, with the exception of stroke progression - at least a 2-point deterioration on the Scandinavian Stroke Scale within 72 hours of onset - which was significantly more common in the candesartan than placebo groups, at 6% versus 4%.
Berge therefore concluded that there is currently "no indication for routine BP lowering in the acute phase of stroke."
He noted, however, that acute BP reduction has not yet been ruled out for all subgroups of patients. For example, the pilot phase of INTERACT (Intensive Blood Pressure Reduction in Acute Cerebral Hemorrhage Trial) found that acute BP lowering limited bleeding in patients with hemorrhagic stroke, although it did not influence clinical outcomes. The phase III study is ongoing.
MedWire (www.medwire-news.md) is an independent clinical news service provided by Current Medicine Group, a trading division of Springer Healthcare Limited. © Springer Healthcare Ltd; 2011
By Eleanor McDermid