Background: Systemic hemodynamic factors may affect blood flow to the brain, yet the influence of volume status and the use of fluid administration to improve perfusion in acute ischemic stroke remains unproven. We correlated the presence of dehydration and volume status defined by initial lab values with perfusion MRI and collaterals at angiography in middle cerebral artery (MCA) stroke patients.
Methods: Retrospective analysis of a consecutive series of isolated M1 MCA occlusions was conducted at an expert core lab to quantify acute Tmax volumes, Tmax hypoperfusion severity ratios and ASITN collateral grade on digital subtraction angiography (DSA). Blood urea nitrogen (BUN) and creatinine (Cr) measured during triage were correlated with hypoperfusion and ASITN/SIR grade. Statistical methods included correlations and ANOVA.
Results: 95 patients (median age 74 (24-101) years; 71 women; median NIHSS 16; median time to MRI, 4h06min) with acute stroke due to M1 occlusion (52 proximal, 43 distal) had contemporaneous BUN/Cr, perfusion MRI and DSA during a 6-year period. Dehydration was noted in 38% (BUN/Cr>20) and 71% (BUN/Cr>15) of patients. Tmax>6sec volumes were median 197 cc (IQR 102-347), with Tmax hypoperfusion severity ratios of 10/6 (median 0.80 (IQR 0.72-0.87)). DSA collateral grade was median 2 (IQR 2-3). Volume status or BUN/Cr was distinct from Tmax hypoperfusion severity at all thresholds, including Tmax>6s (r=0.143, p=0.166), Tmax 10/6 (r=0.114, p=0.271). Direct correlation between BUN/Cr and DSA collateral grade was also unapparent (r=0.034, p=0.744).
Conclusions: Dehydration and the degree of volume depletion may be common, but are not associated with the severity of collateral perfusion in acute M1 MCA occlusion. Collateral grade defined by DSA and the associated severity of hypoperfusion in the brain is unrelated to intravascular volume status.