Blood Clot Dissolution and Reentry into Circulation After Thrombolysis

Mechanism of Thrombolysis and Clot Dissolution

Thrombolytic agents work by activating plasminogen to plasmin, which then degrades fibrin in the clot structure, breaking it down into smaller fragments 1, 3
During intra-arterial thrombolysis, as the thrombus dissolves, the microcatheter is typically advanced into the remaining thrombus where additional thrombolysis is performed, allowing the fragments to enter the circulation 1
The goal of thrombolytic therapy is to achieve rapid recanalization with as little thrombolytic agent as possible, to limit the extent of brain infarction and reduce hemorrhage risk 2

Different thrombolytic agents have varying effects on how clots dissolve and re-enter circulation 3
Fibrin-selective agents are active primarily at the site of thrombosis 1, 3
Non-fibrin-selective agents can result in systemic hypofibrinogenemia 3

The recanalization process is a primary goal of thrombolytic therapy and necessarily involves the dissolved clot material re-entering circulation 4
Recanalization rates with intra-arterial thrombolysis average 70% compared with 34% for intravenous thrombolysis for major cerebrovascular occlusions 4
Successful recanalization is associated with improved clinical outcomes in stroke patients, especially when achieved early (within 3-6 hours) 4, 5

There is a 12-17% risk of embolism during thrombolysis as fragments of the dissolving clot enter circulation 6
To reduce embolic complications, heparin is often administered during thrombolysis to prevent new clot formation as the original clot dissolves 7

During intra-arterial thrombolysis, superselective angiography is performed at regular intervals to assess the degree of clot lysis 1, 2
This monitoring allows visualization of the dissolving clot and adjustment of the dosage and volume of the thrombolytic agent 2

The relationship between recanalization and clinical outcome depends on several factors including collateral circulation, location and extent of the clot, and time from symptom onset to treatment 4