PRESENTING PULSE PRESSURE PREDICTS THROMBOLYTIC THERAPY-RELATED INTRACRANIAL HEMORRHAGE - THROMBOLYTIC PREDICTIVE INSTRUMENT (TPI) PROJECT RESULTS

Background In selecting patients with acute myocardial infarction for thrombolytic therapy, it is important to identify patients who are at high risk for intracranial hemorrhage, for whom thrombolytic therapy i s ill advised. We hypothesized that presenting pulse blood pressure, r epresenting the ''hammer'' effect on cerebral vessels and the effects of age on arterial compliance, might predict thrombolysis-related intr acranial hemorrhage better than systolic, diastolic, or mean arterial blood pressures. Methods and Results Of 3483 Thrombolytic Predictive I nstrument (TPI) Project subjects receiving thrombolytic therapy for ac ute infarction, we identified and obtained detailed clinical data on t he 19 with treatment-related intracranial hemorrhages confirmed by com puted tomography and on 175 matched controls. Systolic, diastolic, mea n arterial, and pulse blood pressures were each significantly related to the occurrence of intracranial hemorrhage, with pulse pressure most highly related. The mean pulse pressure in patients who developed int racranial hemorrhage was 63 mm Hg, 34% higher than the 47 mm Hg mean v alue for those not developing hemorrhage (P = .0001). Excess pulse pre ssure, defined as the extent to which a patient's pulse pressure excee ded 40 mm Hg for systolic blood pressures of at least 120 mm Hg, was e ven more strongly related: its mean value of 23 mm Hg for patients was 130% higher than its mean value of 10 mm Hg for controls (P < .0001). With logistic regression models to estimate the relative risks (odds ratios) for intracranial hemorrhage conferred by each form of blood pr essure, the relative risk for hemorrhage was greatest for excess pulse pressure: for each 10-point pulse pressure excess, the relative risk for intracranial hemorrhage was increased by 1.85 (P = .0002; 95% conf idence interval [CI], 1.34 to 2.55) by itself and 1.76 (P = .001; 95% CI, 1.26 to 2.46) when adjusted for age. In this sample, excess pulse pressure by itself predicted hemorrhage as well as systolic pressure a nd age together. When excess pulse pressure was combined with age to m ake a logistic regression model predicting intracranial hemorrhage, ag e contributed less to the prediction than when combined with the other blood pressure forms, even though this model predicted better than an y other combination of age and pressure (receiver-operating characteri stic curve area, 0.82 versus 0.77 with systolic pressure and age, 0.75 with mean arterial pressure, 0.71 with diastolic pressure, and 0.81 w ith both systolic and diastolic pressures). Conclusions We found that excess pulse blood pressure predicted thrombolysis-related intracrania l hemorrhage better than other forms of pretreatment blood pressure, p erhaps better describing the pathophysiology of intracranial hemorrhag e, including the effect of age. These findings will need confirmation in larger studies with comparable clinical detail.