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Successful Percutaneous Treatment of Suspected Embolic Left Main Thrombosis in a Patient with a Mechanical Aortic Valve

Mitul Patel, MD, Munveer Bhangoo, MD, Anand Prasad, MD

Mitul Patel, MD, Munveer Bhangoo, MD, Anand Prasad, MD

ABSTRACT: Left main coronary artery thrombosis is a rare but potentially fatal phenomenon. We present the unusual case of total occlusion of the left main coronary artery suspected to be secondary to embolized thrombus from a patient’s mechanical, prosthetic aortic valve resulting in an anterior wall ST elevation myocardial infarction and cardiogenic shock. The acute interventional management and review of literature of left main thrombosis is described.

J INVASIVE CARDIOL 2011;23(11):E263-E266

Key words: total occlusion, PCI, STEMI

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The incidence of acute ST-elevation myocardial infarction (STEMI) secondary to occlusion of the left main coronary artery (LMCA) is rare with rates ranging from 0.8 to 1.7% of all STEMI cases.1 The optimal management of patients presenting with left main thrombosis is unclear based on the current literature. Most patients present in cardiogenic shock, which, in itself portends a grave prognosis, and is usually fatal without emergent revascularization. Unfortunately, revascularization either by emergency coronary artery bypass surgery or primary percutaneous coronary intervention (PCI) in the setting of acute myocardial infarction and cardiogenic shock are associated with mortality rates as high as 50%.2 Although plaque rupture and subsequent thrombosis represent the mechanism for infarction in the majority of STEMI patients, embolism to the LMCA has been previously described. We present a case of left main thrombosis and cardiogenic shock in a patient with a prosthetic mechanical aortic valve, subtherapeutic INR, and otherwise angiographically normal coronary arteries — suggesting an embolic etiology. The acute interventional management and review of literature of left main thrombosis is described.

Case Report. A 59-year-old female with a of history Type 2 diabetes mellitus and mechanical bi-leaflet aortic valve prosthesis presented with the acute onset of substernal chest pain and anterolateral ST elevations. The patient’s aortic valve replacement had been performed 4 years earlier for a stenotic bicuspid valve with no prior history of concomitant coronary artery disease. The patient was noted to have bibasilar rales and hypotension (systolic blood pressure of 70 mmHg) requiring intravenous dopamine. Given evidence of an evolving STEMI and shock, she was urgently taken to the cardiac catheterization laboratory.

Diagnostic angiography of the left coronary system demonstrated complete occlusion of the LMCA (Figure 1). Fluoroscopy was also notable for a normal opening and closing bi-leaflet mechanical aortic valve. Given the scenario of cardiogenic shock, the decision was made to proceed with primary percutaneous coronary intervention. An intra-aortic balloon pump was placed for hemodynamic support. Intraveneous heparin and eptifibatide were administered with a peak activated clotting time of 293 seconds. A 300 cm BMW wire (Abbott Vascular) was advanced across the LMCA and positioned in the left anterior descending artery. After confirmation of intra-luminal location, a 2.0 x 15-mm Maverick balloon (Boston Scientific) was used to perform initial angioplasty of the LMCA with restoration of TIMI 2 flow, but with significant residual thrombus burden. Next, a 6 Fr ExPort catheter (Medtronic) was used to perform aspiration thrombectomy without retrieval of visible thrombus. A 7 Fr ExPort catheter was subsequently used to perform additional thrombectomy passes with improvement in flow (Figure 2) and removal of visible clot (Figure 3). However, given a persistently large clot burden in the LMCA, the decision was made to stent the vessel and compress the thrombus against the vessel wall. The left circumflex was a small non-dominant vessel, and a 2.75 x 23-mm Vision bare-metal stent (Abbott Vascular) was deployed in the LMCA into the LAD. The stent was ultimately post-dilated with a 3.5 x 15-mm NC Quantum balloon (Boston Scientific) to high pressure. Final angiography revealed TIMI 3 flow and no significant disease in the LAD (Figure 4). The right coronary artery was similarly free of significant angiographic disease (Figure 5).

Laboratory results ultimately revealed a subtherapeutic INR at 1.4. The patient admitted to non-compliance with warfarin therapy. Subsequent transesophageal echocardiography revealed no evidence of aortic valve dysfunction or evidence of valvular thrombus. The patient was treated with low dose aspirin, clopidogrel and warfarin and discharged in excellent condition with a preserved ejection fraction.

Discussion. LMCA thrombosis has been described in prior studies and case reports and can have variable presentations.3–7 Although patients may present with unstable angina or non-ST elevation myocardial infarctions, the great majority present in either cardiogenic shock or as victims of sudden cardiac death.8,9 Prior studies have demonstrated that anywhere from 63 to 92% of patients presenting with LMCA occlusion present in cardiogenic shock.1,7,9,10 Two high volume interventional centers in Melbourne, Australia found that out of 1,115 consecutive primary percutaneous interventions for acute myocardial infarctions over a 4-year period, 28 (2.5%) were due to left main thrombosis. They noted 18 (64%) of these patients presented in cardiogenic shock, while 10 (36%) patients were survivors of cardiac arrest.1 Furthermore, subgroup analysis of the SHOCK trial in which the left main was the culprit vessel suggested a 1-year mortality of 75% irrespective of the randomized management strategy.11

Various etiologies of left main coronary artery occlusion have been previously described including acute plaque rupture,12,13 embolized thrombus from intracardiac sources,4,6,14,15 embolization of intracardiac masses,16 dissection,17 catheter-induced,5 cocaine-induced plaque rupture or spasm,18 mycotic aneurysms of the LMCA,19 extrinsic compression from the pulmonary artery,20 as a complication of radiofrequency ablation procedures involving the AV-node,21 fibrous intimal proliferation after cardioplegia during bypass or valve replacement surgery,22 and blunt chest trauma.23

The acute management of this morbid condition can be quite challenging, but life preserving. Although there is a paucity of information, the ACC/AHA guidelines as well as data from the SHOCK trial support emergent revascularization either percutaneously or surgically.2,24 In the stable subset of patients presenting without ST elevation or hemodynamic instability, individual case reports of treatment with intravenous heparin in addition to either thombolytics3,25 or glycoprotein IIb/IIIa inhibitors26,27 have shown favorable results. In the few studies involving patients with acute myocardial infarction due to left main thrombosis, emergent surgical management yielded in-hospital mortality rates ranging from 46–53% with patients in cardiogenic shock representing the high end of the range.28–30 Reports involving percutaneous management of acute left main thrombosis or occlusion have found comparatively lower rates of in-hospital mortality (35-46%) when compared to the aforementioned surgical outcomes.1,7,31

In the present case, we speculate that the etiology of the left main thrombus was due to embolism from the prosthetic aortic valve. This assertion is based on the absence of significant atherosclerosis in the remainder of the coronary arteries in the setting of a mechanical aortic valve with a subtherapeutic INR. However, given the patient’s history of diabetes and the lack of intravascular ultrasound evaluation of the coronary vessels, we cannot rule out the possibility of in situ plaque rupture.

From a technical standpoint, aspiration thrombectomy proved to be of limited utility for complete thrombus removal in our case due to what was felt to be organized clot. Initial aspiration with a 6 Fr aspiration catheter was unsuccessful, but use of a larger lumen 7 Fr catheter yielded several fragments of thrombus. Although prior case reports of aspiration thrombectomy in the LMCA are available, neither of the previously published cases involved acute STEMI due to LMCA thrombosis.32,33 The use of rheolytic thrombectomy with the Angiojet catheter may be helpful in this context.34 In addition, the intra-arterial injection of a glycoprotein 2b/3a inhibitor could be considered — particularly to reduce infarct size.35 Finally, data are lacking on the utility of intra-aortic balloon counterpulsation in emergent, unprotected left main intervention during STEMI.  Restoration of flow with immediate balloon angioplasty or aspiration thrombectomy may, in itself, improve the patient’s hemodynamics and obviate the need for balloon pump support.  However, these interventions may also lead to no-reflow which, in the setting of left main thrombosis, may have fatal consequences. In this particular circumstance, cardiogenic shock necessitated immediate balloon pump insertion, which provided excellent hemodynamic support during this complex case.

To our knowledge, the percutaneous management of left main occlusion due to suspected embolized thrombus has not been described in the literature. Our case demonstrates the feasibility of percutaneous intervention with aspiration and stenting for this otherwise morbid condition.

References

  1. Prasad SB, Whitbourn R, Malaiapan Y, Ahmar W, MacIsaac A, Meredith IT. Primary percutaneous coronary intervention for acute myocardial infarction caused by unprotected left main stem thrombosis. Catheter Cardiovasc Interv 2009;73:301-307.
  2. Hochman JS, Sleeper LA, Webb JG, et al. Early revascularization in acute myocardial infarction complicated by cardiogenic shock. SHOCK Investigators. Should We Emergently Revascularize Occluded Coronaries for Cardiogenic Shock. N Engl J Med 1999;341:625-634.
  3. Aydin M, Ozeren A, Bilge M. Acute incomplete thrombotic occlusion of distal left main coronary artery treated by tissue plasminogen activator. Heart 2004;90:242.
  4. Bruno P, Massetti M, Babatasi G, Khayat A. Catastrophic consequences of a free floating thrombus in ascending aorta. Eur J Cardiothorac Surg 2001;19:99-101.
  5. Gunduz H, Akdemir R, Arinc H, Ozhan H, Tamer A, Uyan C. Iatrogenic left main coronary artery thrombosis during percutaneous coronary intervention. Int J Cardiol 2005;102:345-347.
  6. Jain A, Mazanek GJ, Armitage JM. Unstable angina secondary to left main coronary thrombus extending from prosthetic aortic valve. Cathet Cardiovasc Diagn 1988;15:271-272.
  7. Marso SP, Steg G, Plokker T, et al. Catheter-based reperfusion of unprotected left main stenosis during an acute myocardial infarction (the ULTIMA experience). Unprotected Left Main Trunk Intervention Multi-center Assessment. Am J Cardiol 1999;83:1513-517.
  8. Klein AJ, Casserly IP, Messenger JC. Acute left main coronary arterial thrombosis — a case series. J Invasive Cardiol 2008;20:E243-E246.
  9. De Luca G, Suryapranata H, Thomas K, et al. Outcome in patients treated with primary angioplasty for acute myocardial infarction due to left main coronary artery occlusion. Am J Cardiol 2003;91:235-238.
  10. Lee SW, Hong MK, Lee CW, et al. Early and late clinical outcomes after primary stenting of the unprotected left main coronary artery stenosis in the setting of acute myocardial infarction. Int J Cardiol 2004;97:73-76.
  11. Sanborn TA, Sleeper LA, Webb JG, et al. Correlates of one-year survival inpatients with cardiogenic shock complicating acute myocardial infarction: Angiographic findings from the SHOCK trial. J Am Coll Cardiol 2003;42:1373-1379.
  12. Rdzanek A, Pietrasik A, Kochman J, Wilczynska J, Opolski G. Acute coronary syndrome caused by left main coronary artery plaque rupture and thrombosis — resolution after pharmacological treatment. Int J Cardiol 2007;117:e92-e94.
  13. Scacciatella P, Ebrille E, Infantino V, Amato G, Levis M, Marra S. Left main minimal plaque burden complicated by an acute massive thrombosis: diagnostic and therapeutic strategies. J Am Cardiovasc Med (Hagerstown, Maryland) 2010.
  14. Maddoux GL, Goss JE, Ramo BW, et al. Left main coronary artery embolism: a case report. Cathet Cardiovasc Diagn 1987;13:394-397.
  15. Yavuzgil O, Ozerkan F, Gurgun C, Zoghi M, Can L, Akin M. Exercise testing induces fatal thromboembolism from mechanical mitral valve. Tex Heart Inst J 2002;29:48-50.
  16. Tomita Y, Endo T, Takano T, Hayakawa H, Tamura K, Sugisaki Y. Extensive hemorrhagic myocardial infarction associated with left atrial myxoma. Cardiology 1992;81:384-388.
  17. Justice LT, Dauterman K, Smedira NG, Moliterno DJ. Left main dissection and thrombosis in a young athlete. Cardiol Rev 2005;13:260-262.
 
  1. Apostolakis E, Tsigkas G, Baikoussis NG, Koniari I, Alexopoulos D. Acute left main coronary artery thrombosis due to cocaine use. J Cardiothoracic Surg 2010;5:1-3.
  2. Westover K, Benedick B. Mycotic aneurysm of the left main coronary artery producing acute coronary occlusion and purulent pericarditis. Int J Cardiol  2007;114:E81-E82.
  3. Kawase T, Ueda H, Watanabe N, et al. A case of acute coronary syndrome caused by extrinsic compression of the left main coronary artery due to pulmonary hypertension. Journal of Cardiology Cases 2010;2:e154-e158.
  4. Kharrat I, Charfeddine H, Sahnoun M, et al. Left main coronary thrombosis: unusual complication after radiofrequency ablation of left accessory atrioventricular pathway. J Electrocardiol 2008;41:683-685.
  5. Thomopoulou S, Sfirakis P, Spargias K. Angioplasty, stenting and thrombectomy to correct left main coronary stem obstruction by a bioprosthetic aortic valve. J Invasive Cardiol 2008;20:E124-E125.
  6. Unterberg C, Buchwald A, Wiegand V. Traumatic thrombosis of the left main coronary artery and myocardial infarction caused by blunt chest trauma. Clin Cardiol 1989;12:672-674.
  7. Kushner FG, Hand M, Smith SC Jr, et al. 2009 Focused Updates: ACC/AHA Guidelines for the Management of Patients With ST-Elevation Myocardial Infarction (updating the 2004 Guideline and 2007 Focused Update) and ACC/AHA/SCAI Guidelines on Percutaneous Coronary Intervention (updating the 2005 Guideline and 2007 Focused Update): a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines. Circulation 2009;120:2271-2306.
  8. Lew AS, Weiss AT, Shah PK, Fishbein MC, Berman DS, Maddahi J. Extensive myocardial salvage and reversal of cardiogenic shock after reperfusion of the left main coronary artery by intravenous streptokinase. Am J Cardiol 1984;54:450-452.
  9. Michaels AD, Whisenant B, MacGregor JS. Multivessel coronary thrombosis treated with abciximab (ReoPro) in a patient with essential thrombocythemia. Clin Cardiol 1998;21:134-138.
  10. Rechavia E, Wurzel M. Platelet glycoprotein IIb/IIIa receptor blockade in acute myocardial infarction associated with thrombotic occlusion of the left main coronary artery. Circulation 1998;98:1249-1250.
  11. Nakanishi K, Oba O, Shichijo T, Nakai M, Sudo T, Kimura K. [Study on risk factors and late results of coronary artery bypass grafting for acute myocardial infarction]. Nippon Kyobu Geka Gakkai Zasshi 1997;45:950-957.
  12. Shigemitsu O, Hadama T, Miyamoto S, Anai H, Sako H, Iwata E. Acute myocardial infarction due to left main coronary artery occlusion. Therapeutic strategy. Jpn J Thorac Cardiovasc Surg 2002;50:146-151.
  13. Spiecker M, Erbel R, Rupprecht HJ, Meyer J. Emergency angioplasty of totally occluded left main coronary artery in acute myocardial infarction and unstable angina pectoris — institutional experience and literature review. Eur Heart J 1994;15:602-607.
  14. Tan CH, Hong MK, Lee CW, et al. Percutaneous coronary intervention with stenting of left main coronary artery with drug-eluting stent in the setting of acute ST elevation myocardial infarction. Int J Cardiol 2008;126:224-228.
  15. Bhindi R, Ramsay DR, Rees DM. Left main coronary artery “embolectomy” using a novel, straightforward technique. Int J Cardiol 2006;113:345-347.
 

  1. Hajek P, Alan D, Vejvoda J, et al. Treatment of a large left main coronary artery thrombus by aspiration thrombectomy. J Cardiothoracic Surg  2009;27:352-354.
  2. Taghizadeh B, Chiu JA, Papaleo R, Farzanegan F, DeLago A. AngioJet thrombectomy and stenting for reperfusion in acute MI complicated with cardiogenic shock. Catheter Cardiovasc Interv 2002;57:79-84.
  3. Gu YL, Kampinga MA, Wieringa WG, et al. Intracoronary versus intravenous administration of abciximab in patients with ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention with thrombus aspiration: the comparison of intracoronary versus intravenous abciximab administration during emergency reperfusion of ST-segment elevation myocardial infarction (CICERO) trial. Circulation 2010;122:2709-2717.

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From the Division of Cardiology, University of California San Diego, San Diego, California.
Disclosure: The authors have completed and returned the ICMJE Form for Disclosure of Potential Conflicts of Interest. No conflicts of interest were reported regarding the content herein.
Manuscript submitted March 24, 2011, provisional acceptance given April 14, 2011, final version accepted May 2, 2011.
Address for correspondence: Dr. Anand Prasad, University of California San Diego, California Division of Cardiology, 200 West Arbor Drive, San Diego, CA 92103. Email: anandprasadmd@gmail.com