ABSTRACTBACKGROUND AND PURPOSEWe investigated the relationship between transcranial Doppler (TCD) pulsatility index (PI) and central aortic pressure by measurement of the aortic augmentation index (AIx).METHODSWe enrolled 148 consecutive patients with a diagnosis of acute ischemic stroke. Patients were eligible for the study if they experienced their first ischemic stroke within the preceding 7 days and were 45 years of age or older. At Day 7 (±2) after stroke onset, TCD studies were performed and AIx was measured by applanation tonometry on the same days.RESULTSThe mean age was 66.3 (47–90) years and 37.8% were women. The mean middle cerebral artery (MCA) PI was significantly related with age (r =.361), hypertension (r = .184), peripheral systolic blood pressure (SBP; r = .211), peripheral pulse pressure (PP; r = .396), aortic SBP (r = .184), aortic DBP (r = –.181), and aortic PP (r = .371). The basilar artery (BA) PI was significantly related with age (r = .311), peripheral DBP (r = –.267), peripheral PP (r = .358), aortic DBP (r = –.266), and aortic PP (r = .347).CONCLUSIONSTCD PI was significantly related with central aortic pressure, especially PP. The PI in the MCA and BA is closely associated with the pulsatile component of BP in the systemic circulation.