Study Treatment Regimen ICH rate, Heparin + Placebo ICH rate Heparin + Lytic Major hemorrhage, Heparin + Placebo Major hemorrhage, Heparin + Lytic Alteplase versus placebo PIOPED 1990 40 - 80 mg alteplase 0/4 0/9 0/4 1/9 Levine 1990 0.6 mg/kg alteplase 0/25 0/33 3/25 3/33 Dalla - Volta 1992 100 mg alteplase 0/16 1/20 2/16 3/20 Konstantinides 2002 (MAPPET) 100 mg alteplase 0/138 0/118 5/138 1/118 Fassulo 2011 100 mg alteplase 0/35 0/37 1/35 2/37 Sharifi 2012 (MOPETT) Up to 50 mg alteplase 0/60 0/61 0/60 0/61 All Alteplase vs. placebo trials 0/278 1/278 (0.4%) 11/278 (4.0%) 10/278 (3.6%) Tenecteplase versus placebo Becattini 2010 0/30 1/28 1/30 2/28 Meyer 2014 (PEITHO) 1/499 10/506 12/499 58/506 Kline 2014 (TOPCOAT) 0/43 1/40 0/43 1/40 All Tenecteplase versus placebo 1/572 (0.2%) 12/574 (2.1%) 13/572 (2.3%) 61/574 (11%) Complication rates of placebo - controlled RCTs involving thrombolysis for P E Review of this raw data leads to some interesting conclusions. First, tenecteplase leads to a higher hemorrhage risk than alteplase (so tenecteplase - based trials cannot be generalized to reach conclusions about alteplase ). Second, the risk of bleeding from alteplase is relatively low. Only one intracranial hemorrhage is seen, in a trial involving 100 mg alteplase . Of course, bleeding rates of patients outside RCTs will be higher. - Internet Book of Critical Care, by @PulmCri t