![]() 11 Different characteristics of fibrin network also affect the behaviour of thrombus to intervention. Red thrombus, compared with white thrombus, tends to be more resistant to intervention and is associated with worse clinical outcomes including 30-day MACE and mortality. The prognosis when dealing with intracoronary thrombus is determined not only by thrombus burden but also by thrombus composition. Thus, both TIMI thrombus grade and angiographic features should be considered when assessing thrombus burden, to determine the strategy for intervention.īeyond Thrombus Burden: The Impact of Thrombus Composition It should be noted that coronary arteries of different sizes with identical TIMI thrombus grades may well have considerably different absolute thrombus burdens. 10 These features were shown to be independent predictors of slow-flow and no-reflow after primary PCI, which in turn was associated with higher 30-day mortality. Thrombus burden can also be assessed by angiographic morphologic features as proposed by Yip et al ( Table 2). By this approach, a large thrombus burden of grade 4 has been reported to be a predictor of stent thrombosis and major adverse cardiac events (MACE) at 2 years. Thereafter, the thrombus grading can be re-stratified to TIMI grade 1–4, with grade 1–3 indicating a small thrombus burden and grade 4 representing a large thrombus burden. 7 Thus, when total thrombotic occlusion is encountered, it is recommended to first establish flow by guidewire crossing or by passage of a non-inflated balloon. ![]() In fact, after the exclusion of patients with patent infarct-related artery, TIMI grade 5 became not to be regarded as an independent predictor of distal embolisation. 8 Notably, total thrombotic occlusion is given the highest grade of 5, but the actual thrombus load in a totally occluded lesion is uncertain. 7 As a practical approach, a simplified bi-level categorisation has been proposed, whereby TIMI grades 1–3 are classified as low grade while TIMI grades 4–5 are classified as high grade. 6 High TIMI thrombus grade has been shown to be a predictor of distal embolisation in primary angioplasty. The most widely used tool to assess thrombus burden is the Thrombolysis in MI (TIMI) thrombus grading, which is largely based on the dimension of thrombus relative to the vessel size ( Table 1). Thrombus burden is a predictor of a worse outcome. Predictors of Worse Outcome: Thrombus Burden The presence of coronary thrombus during PCI has been shown to be associated with adverse procedural and clinical outcomes, including no-reflow, MI, emergency bypass surgery and in-hospital mortality. Intracoronary thrombus can lead to occlusion of an epicardial vessel or its branches during PCI and can cause distal embolisation resulting in distal vessel occlusion and no-reflow. Impact of Thrombus on Percutaneous Coronary Intervention and Clinical Outcome Steps to follow include consideration of the various strategies for managing a thrombus, then to adopt the appropriate strategy and algorithm based on the perceived significance of the thrombus and its response to an individual strategy. The first step is to assess the potential impact of the thrombus on PCI and clinical outcome. Interventionists can take inspiration from the ancient wisdom to fight the enemy. 2Ĭlot is often the enemy during primary percutaneous coronary intervention (PCI). The Art of War, an ancient military treatise composed around the 5th century BCE, stressed the importance of knowing the enemy to adopt different strategies when fighting the enemy, to attack, to surround, to avoid, to battle, to flee. “ If you know the enemy and know yourself, your victory will not stand in doubt.” 1 The key remains to adopt different strategies selectively and appropriately in different scenarios. Of note, most of these strategies have not been demonstrated to be beneficial on routine use. This is to be followed by choosing the appropriate strategy: to attack – aspiration and mechanical thrombectomy to surround – pharmacological therapy, including oral and parenteral antiplatelet therapy and intracoronary thrombolytic therapy to avoid – stenting strategies including direct stenting and deferred stenting to battle – stenting under a distal protection device or stenting across local obstructive thrombus or to flee – to move from percutaneous coronary intervention to optimal antithrombotic therapy and circulatory support when flow fails to be regained. assess the thrombus burden, by both Thrombolysis in MI thrombus grade and angiographic features. Taking inspiration from the ancient wisdom of fighting a war, an interventionist should first look into the strength of the enemy, i.e. Clot is often the enemy during primary percutaneous coronary intervention.
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