Figura 1. A: Large-diameter circumflex artery with an obtuse marginal branch and a very ectatic segm...

Figura 2. Circumflex artery with total resolution of the associated thrombus.

Introduction

Intracoronary thrombi are a rare but significant cause of acute coronary syndromes (ACS), both with ST-segment elevation (STEACS) and without it (NSTEACS). Management of these cases remains a therapeutic challenge, as large thrombi pose specific risks during percutaneous coronary intervention (PCI), such as distal thrombus migration or the no-reflow phenomenon. In these cases, implementing both pharmacological and interventional strategies to reduce thrombotic burden is crucial. Here, we report the case of a 60-year-old male patient who presented with ACS secondary to a large intracoronary thrombus, and we describe its resolution through medical and percutaneous treatment.

Clinical case

We present the case of a 60-year-old man, a smoker without other known cardiovascular risk factors, who came to the Emergency Room with typical central chest pain resolved after administering morphine chloride 3 mg, sublingual nitroglycerin/caffeine citrate, and aspirin 300 mg. The initial ECG showed no signs of acute ischemia, and the enzymatic curve was positive (high-sensitivity troponin I 344→565.7), leading to the patient›s admission to the Intensive Care Unit.

He was asymptomatic and his evolution was good. An echocardiogram revealed no significant abnormalities. The following day, cardiac catheterization revealed a large-diameter circumflex artery with an obtuse marginal branch and a very ectatic segment (>5 mm) with distal occlusion (TIMI 0), and an image of a large thrombus inside it (Figure 1A). Given the lack of distal flow and the risks associated with thrombus manipulation, including possible distal or systemic migration, percutaneous coronary intervention (PCI) on the distal circumflex artery using a 2.0 conventional balloon was the selected alternative. This achieved vessel reopening and restoration of antegrade flow (TIMI 2–3) (Figure 1B), with a slight lesion beyond the aneurysmal area. The other vessels were in good health, so the procedure was concluded.

Initial treatment included triple antiplatelet therapy with aspirin 100 mg/day, clopidogrel 75 mg/day, and intravenous tirofiban for 24 hours. After discontinuing tirofiban, the patient received anticoagulation with enoxaparin 6000 IU every 12 hours, which was maintained throughout hospitalization.

During the remainder of his stay in the Department of Cardiology, the patient remained asymptomatic without complications. Upon discharge, and after clinical assessment, dual antiplatelet therapy (aspirin + clopidogrel) was continued alongside oral anticoagulation with rivaroxaban 20 mg/day for an additional four weeks.

Four weeks later, the patient was readmitted for a scheduled follow-up catheterization, which showed complete resolution of the thrombus, persistence of the distal lesion, and good antegrade flow (TIMI 3) (Figure 2). Based on this, oral anticoagulation was discontinued, and dual antiplatelet therapy was maintained.

According to current guidelines, PCI remains the preferred treatment option in patients with STEACS or NSTEACS1, However, the management of large intracoronary thrombi in cases of acute coronary syndrome (ACS) remains a therapeutic challenge. Various pharmacological and interventional strategies are employed to reduce thrombotic burden.

Two critical issues arise in this case: immediate management during PCI and long-term pharmacological therapy2.

Regarding PCI for intracoronary thrombi, the approach varies depending on thrombus size. For small thrombi (TG 0–2), direct stenting may be considered. In cases of large intracoronary thrombi (TG 5), such as in this patient, PCI can be challenging due to the risk of distal or systemic migration, no-reflow, or embolization of non-culprit vessels3. Antegrade flow assessment is essential; when absent, mechanical aspiration thrombectomy or distal balloon intervention can be attempted to restore flow. However, there is no ideal approach, and management must be individualized based on patient condition and operator experience4.

On the other hand, regarding antithrombotic treatment, dual antiplatelet therapy seems to be the best alternative as it provides clear benefit by reducing thrombotic burden and improving clinical outcomes. Potent P2Y12 inhibitors (ticagrelor or prasugrel) are preferred due to their rapid action and superior clinical and angiographic outcomes. Clopidogrel is also an alternative, particularly for elderly patients with high bleeding risk and socioeconomic constraints5. Glycoprotein IIb/IIIa inhibitors also seem to effectively dissolve intracoronary thrombi and restore TIMI flow. Current guidelines recommend their use for no-reflow phenomena, thrombotic complications, or intracoronary thrombi6. The most commonly used agents are abciximab and tirofiban, with no clear superiority between them. Some small-scale studies suggest intracoronary abciximab may outperform intravenous options in cases without increased hemorrhagic events; however, further evidence is needed to expand its use7.

As for long-term anticoagulation in patients with large intracoronary thrombi, there is limited literature available. Published cases have used subcutaneous enoxaparin, warfarin, or new direct oral anticoagulants (NDOACs). In this case, given the patient’s preference for oral therapy and limited access to INR monitoring, rivaroxaban 20 mg/day for four weeks was the chosen alternative. After confirming successful resolution of the thrombus, anticoagulation was discontinued8.

Conclusion

Large intracoronary thrombi remain a challenge in the treatment of acute coronary syndromes, requiring a multidisciplinary approach that combines interventional strategies and antithrombotic therapies. In this case, the combination of percutaneous intervention with a conventional balloon to restore coronary flow, along with initial intensive treatment with clopidogrel, aspirin, tirofiban, and enoxaparin, followed by anticoagulation with rivaroxaban, resulted in complete thrombus resolution with favorable clinical outcomes. This case underscores the importance of tailoring treatment to the patient’s condition and the characteristics of the thrombus.

1. Collet JP, Thiele H, Barbato E, et al.; Siontis GCM; ESC Scientific Document Group. 2020 ESC Guidelines for the management of acute coronary syndromes in patients presenting without persistent ST-segment elevation. Eur Heart J. 2021 Apr 7;42(14):1289-1367. doi: 10.1093/eurheartj/ehaa575. Erratum in: Eur Heart J. 2021 May 14;42(19):1908. Erratum in: Eur Heart J. 2021 May 14;42(19):1925. Erratum in: Eur Heart J. 2021 May 13;: Erratum in: Eur Heart J. 2024 Feb 1;45(5):404-405. PMID: 32860058.

2. Theodoropoulos KC, Felekos I, Hung JD, Khand A, Stables RH. Challenges in Primary PCI: How to Treat a Large Intracoronary Thrombus With TIMI 3 Flow? J InvasiveCardiol. 2022 Feb;34(2):E154-E155. PMID: 35100561.

3. Kumar V, Sharma AK, Kumar T, Nath RK. Large intracoronary thrombus and its management during primary PCI. Indian Heart J. 2020 Nov-Dec;72(6):508-516. doi: 10.1016/j.ihj.2020.11.009. Epub 2020 Nov 19. PMID: 33357638; PMCID: PMC7772595.

4. Miranda-Guardiola F, Rossi A, et al.; Spanish AMIcath Registry. Angiographic quantification of thrombus in ST-elevation acute myocardial infarction presenting with an occluded infarct-related artery and its relationship with results of percutaneous intervention. J IntervCardiol. 2009 Jun;22(3):207-15. doi: 10.1111/j.1540-8183.2009.00464.x.Epub 2009 Apr 14. PMID: 19490354.

5. Hermanides RS, Kilic S, van’t Hof AWJ. Optimal pharmacological therapy in ST-elevation myocardial infarction-a review : A review of antithrombotic therapies in STEMI. NethHeart J. 2018 Jun;26(6):296-310. doi: 10.1007/s12471-018-1112-6. PMID: 29687412; PMCID: PMC5967999.

6. Hermanides RS, van Werkum JW, Ottervanger JP, et al.; Ongoing Tirofiban In Myocardial infarction Evaluation (On-TIME) 2 study group. The effect of pre-hospital glycoprotein IIb-IIIa inhibitors on angiographic outcome in STEMI patients who are candidates for primary PCI. CatheterCardiovascInterv. 2012 May 1;79(6):956-64. doi: 10.1002/ccd.23165. Epub 2011 Dec 12. PMID: 22162050.

7. Thiele H, Wöhrle J, Hambrecht R, et al. Intracoronary versus intravenous bolus abciximab during primary percutaneous coronary intervention in patients with acute ST-elevation myocardial infarction: a randomised trial. Lancet. 2012 Mar 10;379(9819):923-931. doi: 10.1016/S0140-6736(11)61872-2. Epub 2012 Feb 21. PMID: 22357109.

8. Jamal N, Bapumia M. Dual antiplatelet agents and Rivaroxaban for massive intracoronary thrombus in STEMI. Clin Case Rep. 2015 Nov;3(11):927-31. doi: 10.1002/ccr3.389. Epub 2015 Sep 22. Erratum in: Clin Case Rep. 2016 Jun;4(6):623. PMID: 26576274; PMCID: PMC4641476

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