PulmCrit- January 18, 2016 - By Josh Farkas
"Patients undergoing catheter-directed thrombolysis for deep vein thrombosis receive ~1 mg/hour alteplase infusions with monitoring of their fibrinogen levels. Usually, their fibrinogen level remains fairly stable and patients do well. However, occasional patients will experience rapid drops fibrinogen, requiring discontinuation of the thrombolysis. Such patients seem to experience minor bleeding complications (e.g. oozing around intravenous catheters, mucosal bleeding).
Our approach to treating PE with systemic lytics is totally different. We choose an alteplase dose, cross our fingers, and hope for the best. We have no way of predicting how the alteplase will affect the patient’s coagulation system. Usually the alteplase works, sometimes its does nothing, and occasionally the patients bleed.
Rapid thrombolysis is essential in some situations (e.g. STEMI, massive PE). However, stable patients with submassive PE allow us the time to perform thrombolysis similarly to our approach to DVT: slowly and carefully. Instead of giving alteplase over two hours, we could provide alteplase as an infusion over 24 hours. If the coagulation tests started plummeting or the patient developed minor bleeding, we could stop – before the patient progressed to develop severe hemorrhage.
- The ideal approach to dosing alteplase for thrombolysis of PE remains unclear.
- Patients’ response to alteplase varies depending on their balance of pro- vs. anti-fibrinolytic modulators.
- A slow peripheral alteplase infusion (e.g. 1 mg/hour infusion) could allow monitoring of the patient’s response to thrombolysis throughout the procedure, with discontinuation if there were excessive fibrinolysis or bleeding.
- Available data suggests that quarter-dose alteplase is effective. Based on data from >1,000 patients undergoing catheter-directed thrombolysis of PE or DVT, slow infusions of alteplase are safe.
- Controlled thrombolysis using a slow 25-mg alteplase infusion with protocoled monitoring might offer patients the benefit of lytic therapy with an extremely low risk of severe hemorrhage.