Interventional Strategies in Thrombus Management for ST Elevation Myocardial Infarction

Abstract

Many advances have been made in the management of ST elevation myocardial infarction (STEMI) over the past three decades.1 This is owed to insight into role that thrombus has in the obstruction of the infarct-related artery (IRA) and the subsequent cascade of the myocardial ischaemia, cell oedema and myocardial necrosis. The institution of reperfusion therapy has revolutionised the care of patients with STEMI decreasing morbidity and mortality. [2][3][4][5] This therapy, whether it be pharmacologic in the case of fibrinolysis or mechanical in the case of percutaneous coronary intervention (PCI), aims at restoring patency of the IRA and ultimately tissue perfusion. However, even with modern primary PCI, distal embolisation of thrombus is common and about a third of patients have impaired microvascular perfusion despite TIMI 3 flow in infarct vessel.6 This article will review the importance of thrombus in STEMI and approaches to management: mechanical and pharmacologic. The Importance of Thrombus in the Pathophysiology of ST Elevation Myocardial Infarction Mechanism of Acute Coronary Syndrome in the Formation of ThrombusThe pathophysiology of acute coronary syndrome (ACS) is rupture or erosion of the fibrous cap overlying lipid rich plaques within the arterial tree.1 This event exposes pro-inflammatory substances, ultimately resulting in platelet aggregation and formation of obstructive thrombus.1,7 Angiographic evidence of thrombus formation can be seen in more than 90 % of patients who present with ST elevation myocardial infarction (STEMI).8 Plaque rupture usually produces combination of red (cross-linked fibrin and red blood cells) and white (platelet aggregates) thrombus.9 Reperfusion therapy has become the cornerstone in the treatment of STEMI. [10][11][12][13] The basis of this strategy is to restore epicardial blood flow either by the fibrinolysis of thrombus or by mechanical displacement of thrombus in the case of percutaneous coronary intervention (PCI). The Effectiveness of Reperfusion TherapyEarly Success in Thrombus ManagementThe effectiveness of thrombolytic therapy has been well demonstrated in the Second international study of infarct survival (ISIS-2) study. This landmark randomised trial of 17,187 patients compared streptokinase alone, aspirin alone, the combination of aspirin and streptokinase vs neither in patients with suspected acute myocardial infarction (AMI). 2 However, one of the limitations of fibrinolytic therapy is that reperfusion of the infarct artery is only successful in 50-60 % of cases.14 In comparison, primary PCI achieves TIMI 3 flow in 80-90 % of cases and meta-analyses of randomised trials show that PPCI compared to fibrinolysis reduces mortality. 5,15 AbstractThe major limitation of modern primary percutaneous coronary intervention (PPCI) is distal embolisation of thrombus and microvascular obstruction. Microvascular flow, as measured by myocardial blush grade (MPG), predicts mortality after PPCI. Despite initial enthusiasm, current evidence does not support routine use of I...

Use of Intracoronary Thrombolysis for Huge Thrombus Burden in an Ectatic Right Coronary Artery

“…4 Therefore, many strategies have been described to tackle the problem of large IC thrombus. 2 The thrombus can be disrupted with local balloon dilatation or treated with thrombectomy devices such as aspiration catheters or mechanical rheolytic thrombectomy. 8 Injectable antiplatelets, such as GP IIb/IIIa inhibitors, are also used to help reduce thrombus burden and prevent complications.…”

“…The management of these patients is often challenging due to the high thrombus burden, with the use of various available modalities such as manual thrombus aspiration often being inadequate. 2 Presence of a large amount of thrombus has been shown to be associated with poor long-term prognosis and is also often associated with complications such as stent thrombosis, no reflow phenomenon and distal embolisation. 3,4 pain lasting for two hours.…”

“…Intracoronary (IC) lysis is an option that is not considered often either due to lack of clear practice protocols or a high perceived bleeding risk. 2 In addition, the 2017 European guidelines on management of STEMI do not clearly state how these patients should be managed besides the usual procedures, such as aspiration thrombectomy and balloon angioplasty. 5 In this report, we present a case of an occluded ectatic right coronary artery (RCA) presenting as a STEMI which was successfully treated with IC fibrinolysis.…”