Clinical Question: Is thrombolytic therapy better than heparin for patients with pulmonary embolism (PE)?
Setting: Inpatient (any location) with outpatient follow-up
Study Design: Meta-analysis (randomized controlled trials)
Synopsis: These authors did a thorough and well-described search to identify all randomized trials comparing thrombolysis with heparin for the initial treatment of acute PE. They identified 11 studies with a total of 748 patients that measured at least one clinical outcome and employed proper methods for randomization. Only three studies were double-blinded, and five reported proper concealment of allocation. Five studies used streptokinase, two used urokinase, and four used tissue plasminogen activator. Six studies had 31 or fewer patients. Most patients received heparin and warfarin after the initial therapy, and follow-up ranged from 72 hours to 30 days.
No significant reduction was noted in the likelihood of recurrent PE or death in the group receiving thrombolysis (6.7 versus 9.6 percent; odds ratio = 0.67; 95 percent confidence interval, 0.4 to 1.12), and these findings were statistically consistent among studies. Five of the studies included patients with major hemodynamically unstable PE. In this subset, a significant reduction was seen in the likelihood of recurrent PE or death (9.4 versus 19.0 percent; absolute risk reduction = 9.6 percent; number needed to treat = 10).
Bottom Line: Studies of thrombolysis for acute PE are limited by small size, poor allocation concealment and blinding, and a short duration of follow-up. The existing literature does not support the use of thrombolysis in unselected patients with acute PE, but suggests that there may be a benefit in patients with major hemodynamically unstable PE. Further study to confirm the benefit in this subgroup is needed. (Level of Evidence: 2a)