Brain natriuretic peptide and cerebral vasospasm in subarachnoid hemorrhage - Clinical and TCD correlations

Background ann Purpose-Hyponatremia has been shown in association with cere bral vasospasm (CVS) following aneurysmal subarachnoid hemorrhage (SAH). In the past few years there has been increasing evidence that brain natriuret ic peptide (BNP) is responsible for natriuresis after SAH, The purpose of t he present study was to investigate the relationship between BNP plasma con centrations and CVS after aneurysmal SAH. Methods-BNP plasma concentrations were assessed at 4 different time periods (1 to 3 days, 4 to 6 days, 7 to 9 days, and 10 to 12 days) in 19 patients with spontaneous SAH. BNP plasma levels were investigated with respect to n eurological condition, SAH severity on CTI and flow velocities measured by means of transcranial Doppler. Results-Thirteen patients had Doppler evidence of CVS; 7 of these had nonsy mptomatic CVS. In 6 patients, CVS was severe and symptomatic, with delayed ischemic lesion on CT in 5 of these. CVS was severe and symptomatic in 6 pa tients, and delayed ischemic lesions were revealed on CT in 5 of these. BNP levels were found to be significantly elevated in SAH patients compared wi th control subjects (P=0.024). However, in patients without CVS or with non symptomatic CVS, BNP concentrations decreased throughout the 4 time periods , whereas a 6-fold increase was observed in patients with severe symptomati c CVS between the first and the third periods (P=0.0096). A similar trend i n BNP plasma levels was found in patients with severe SAH compared with tho se with nonvisible or moderate SAH (P=0.015). Conclusions-In conclusion, our results show that BNP plasma levels are elev ated shortly after SAH, although they increase markedly during the first we ek in patients with symptomatic CVS. The present findings suggest that secr etion of BNP secretion after spontaneous SAH may exacerbate blood flow redu ction due to arterial vasospasm.