Early computed tomography hypodensity predicts hemorrhage after intravenous tissue plasminogen activator in acute ischemic stroke

Parenchymal hypodensity is a proposed risk factor for hemorrhage after reco mbinant tissue plasminogen activator (TPA) thrombolysis for ischemic stroke . In Buffalo, NY, and Houston, TX, the authors reviewed 70 patients who wer e treated with intravenous TPA for acute middle cerebral artery (MCA) strok e. Two observers blinded to clinical outcome analyzed initial noncontrast h ead computed tomography (CT) scans. Basal ganglia CT hypodensity was quanti tated in Hounsfield units (HUs). Contralateral-ipsilateral difference in de nsity was calculated using the asymptomatic side as a control. Ictus time t o TPA averaged 2.5 hours. Six patients developed symptomatic intraparenchym al hematomas (2 fatal). The hemorrhage group had more severe basal ganglia hypodensity (mean 7.5 +/- 1.4, range 6-10 HU) than the nonhemorrhage group (2.2 +/- 1.4, range 0-9 HU) (P < .0001). The hemorrhage group had hypodensi ty of >5 HU; the nonhemorrhage group had hypodensity of less than or equal to4 HU, except 1 patient with hypodensity of 9 HU. In predicting hemorrhage , the positive predictive value of hypodensity > 5 HU was 86%; the negative predictive value was 100%. Prethrombolysis NIH Stroke Scale (NIHSS) defici t (P = .0007) and blood glucose (P = .005) were also higher in the hemorrha ge group. Age, gender, smoking, hypertension, and ictus time to TPA infusio n did not differ between the 2 groups. Logistic regression indicated that b asal ganglia hypodensity was the best single predictor of hemorrhage. Hypod ensity and NIHSS score together predicted all cases of hemorrhage. The auth ors conclude that basal ganglia hypodensity quantified by CT may be a usefu l method of risk stratification to select acute MCA stroke patients for thr ombolytic therapy.