Improved function and perfusion with pharmacological blood pressure elevation
A few studies have reported improved function in acute stroke with pharmacological elevation of mean arterial pressure (MAP), but statistical correlations between function and MAP have not been documented. We studied 10 acute-subacute stroke patients before, during, and after MAP elevation (using IV phenylephrine and oral agents), with detailed cognitive tests and serial MR perfusion and diffusion scans to identify relationships between MAP, deficits, and regional perfusion. Cognitive assessment included tests of word and sentence comprehension and naming (for dominant hemisphere stroke), and tests of copying and spatial attention (for nondominant stroke). Separate forms of each test, matched in difficulty, were administered daily. Blinded reviewers measured volume of hypoperfused regions on “time to peak” maps. Results: 5 patients showed striking correlations between MAP and 1 or more cognitive tests: in 4 aphasic patients MAP was highly correlated with both naming and word comprehension (r=.88–96; p<.0005-.002 across cases); in 1 case of nondominant stroke MAP was associated with copying score (r=.90; p<.04). Another 3 patients showed fairly high correlations between MAP and naming (r=.67; .78; .94, respectively) that did not reach significance (p=.06–0.12) likely due to too few data points. For each of these 8 cases increased MAP was associated with improved language or visuospatial function, and subsequent falls in MAP were associated with deterioration in function. The last 2 patients showed no significant MAP elevation with therapy and showed no substantial change in function. In 8/8 patients who showed increased MAP and improved cognition, serial MR perfusion scans demonstrated reduction of regional hypoperfusion while MAP (and function) increased. In 1 case, when MAP fell and function deteriorated, repeat perfusion scan showed reversal of the prior improved perfusion. Both (2/2) patients with no increase in MAP or function showed no improvement of perfusion with therapy. Conclusions: In selected patients with recent stroke, raising MAP can be associated both with improvement in specific domains of cognition and with improved regional cerebral perfusion.