Modified thrombolysis feasible for moderate PE
MedWire News: Treatment with half the standard dose of tissue plasminogen activator (tPA) is feasible for patients with moderate pulmonary embolism (PE), according to research presented at the American College of Cardiology's 61st Annual Scientific Session in Chicago, Illinois, USA.
"Systemic thrombolytic therapy, though advocated for massive PE, has not been recommended for moderate PE due to potential bleeding complications," explain Mohsen Sharifi (Arizona Cardiovascular Consultants, Mesa, USA) and colleagues.
Currently, only about 5% of PE cases are considered severe enough to be given thrombolytic agents at full dose. Yet, even moderate cases can lead to recurrent PE, pulmonary hypertension, and other dangerous complications.
Sharifi and team therefore investigated the role of modified or "safe dose" thrombolysis for moderate PE. They randomly assigned 121 patients with symptomatic acute moderate PE to receive tPA plus anticoagulation (tPA group, n=61) or anticoagulation alone (control group, n=60).
The tPA group received approximately half the standard dose of tPA (for those ≥50 kg, 10 mg in 1 minute followed by 40 mg in 2 hours; for those <50 kg, 0.5 mg/kg total dose: 10 mg in one minute followed by the remainder in 2 hours) plus concomitant anticoagulation with a 20% to 30% reduced dose of enoxaparin or heparin. The control group received the standard regimen of anticoagulants alone.
The primary end point of the study was pulmonary hypertension (pulmonary arterial systolic pressure of >40 mmHg), and there was also a composite primary end point of recurrent PE plus pulmonary hypertension.
Sharifi reported that pulmonary hypertension at 28 months was significantly lower in the tPA group than in the control group, at 16% versus 57%. For the composite end point, the corresponding values were 16% and 63%, also a significant difference.
There were no recurrent PEs in the tPA group, compared with three in the control group.
"For both groups, the pulmonary pressure was reduced, but the extent of the reduction was far greater in those who got the tPA than in those who did not," Sharifi observed.
Secondary end points included in-hospital bleeding and duration of hospitalization. There was no bleeding in either group. But hospital stay was significantly reduced in the tPA group compared with the control group, at means of 2.2 versus 4.9 days.
"The duration of hospitalization could be reduced dramatically, and that may have significant health impacts in the future," said Sharifi.
He concluded: "The clinical implications are that the majority of patients with PE who are symptomatic can be safely treated, provided the practitioners use a modified dose of tPA and a lower dose of concomitant anticoagulation. It leads to early hospital discharge and a reduction in pulmonary hypertension in the long run."
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By Laura Cowen