Ann Thorac Surg 2006;81:728-729
© 2006 The Society of Thoracic Surgeons
Case report
Anastomotic Obstruction After Magnetic Vascular Coupling After Minimally Invasive Direct Coronary Artery Bypass Grafting
Uwe Klima, MD, PhD
*
,
Theo Kofidis, MD,
Janina Beilner, CM,
Michael Maringka, MD,
Stephan Kirschner, MD,
Axel Haverich, MD, PhD
Department of Thoracic and Cardiovascular Surgery, Hannover Medical School, Hannover, Germany
Accepted for publication November 11, 2004.
* Address correspondence to Dr Klima, Department of Cardiothoracic Surgery, Hannover Medical School, Carl Neuberg Str. 1, Hannover 30625, Germany (Email: klima{at}thg.mh-hannover.de).
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Abstract
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We report a 61-year-old man who required reoperation 8 months after minimally invasive direct coronary artery bypass grafting after magnetic vascular coupling due to a symptomatic subtotal obstruction at the anastomotic site. It was also determined that the patient had been noncompliant in following the prescribed postoperative antiplatelet therapy.
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Introduction
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The utilization of automatic anastomotic devices in cardiac surgery is expanding. Magnetic vascular coupling constitutes an attractive anastomotic option that significantly shortens the ischemic time when creating the coronary anastomosis on the beating heart and has recently been introduced for multiple vessel revascularization [1, 2]. It is of utmost importance to ensure adequate postoperative antiplatelet therapy in patients treated with this new technique in order to retain unobstructed patency through the magnetically coupled anastomosis. The routine regimen involves clopidogrel (Plavix, Bristol-Myers Squibb/Sanofi Pharmaceuticals Partnership, NY) for 3 months and aspirin indefinitely.
A 61-year-old man with single-vessel coronary artery disease initially underwent minimally invasive bypass grafting using the magnetic vascular grafting technique. During this procedure the anastomotic ports were approximated and connected using the Ventrica magnetic vascular positioner (Ventrica Inc, Fremont, CA). The intraoperative trans-anastomotic flow was optimal at this point, and the anastomosis was free of leakage. The patient had an uneventful postoperative course and was discharged free of angina symptoms.
Four months later the patient presented again with progressive pectoral angina and intractable dyspnea on mild exertion. Subsequently a coronary angiography was performed that revealed flow through the anastomosis with no obvious obstruction. The patient was once again discharged on clopidogrel (Plavix, 75 mg/d) and aspirin (100 mg/d), but he had to be readmitted to the hospital 4 weeks later with worsening chest pain. A treadmill test was positive for myocardial ischemia and a second conventional angiographic evaluation was carried out. The latter provided no definitive evidence of anastomotic malfunction (Fig 1), but was regarded as secondary significance at this point due to the patient's profound symptomatology; hence, the indication for reoperation using extracorporeal circulation emerged. Patient history revealed lack of compliance to follow the therapeutic antiplatelet regime, due to the patient's recent posttraumatic depression with concurrent alcohol abuse after the death of his spouse.
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Fig 1. Left coronary artery angiogram with selective assessment of the internal thoracic artery bypass on the left anterior descending coronary artery, featuring engorged anastomotic appearance due to the coupled magnet structures, before reoperation.
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At reoperation, the magnetic vascular positioner port was inspected and removed. The anastomosis was obstructed subtotally (Fig 2) by extensive neointima formation; hence, the morphologic substrate for the patient's progressive chest pain was confirmed. A radial artery graft was utilized for a mid and distal left anterior descending coronary artery anastomosis using a "jump" technique under extracorporeal circulation. The left internal thoracic artery could not be reused as a conduit because the flow and length of the graft did not enable a sequential graft being necessary at reoperation due to the initial proximal and new additional distal left anterior descending coronary artery stenosis. The postoperative recovery was uncomplicated and the patient was discharged free of symptoms in 8 days with due course on aspirin (100 mg daily).
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Fig 2. Intraoperatively, a subtotal obstruction of the magnetically coupled coronary anastomosis is displayed, associated with extensive neointimal formation.
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Comment
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Platelet inhibition by clopidogrel reduces cyclic flow variations and neointimal proliferation in normal and hypercholesterolemic-atherosclerotic coronary arteries [3]. Omission of clopidogrel medication may well result in boosted neointimal formation and expedite the process of anastomotic obstruction [4]. In addition to hemostatic risk factors such as artificial material at the site of anastomosis, this effect might have been enhanced and ultimately caused the symptomatic obstruction. The lack of compliance by the patient (due to personal distress) delineates the eventual need for more frequent follow-up evaluations in patients who are at risk. Even though this new anastomotic technique is an attractive and efficient method pertaining to the reduction of ischemia and operation duration, or both, it seems to be mandatory to strictly follow the antiplatelet medication regimen until the magnets are covered completely by endothelium.
Of note, the assessment of anastomotic flow, respectively the degree of obstruction using conventional angiography can be limited. This report indicates that even an advanced obstruction can potentially escape diagnosis. This is due to the radiopacity of the ferrous material comprising the magnetic vascular positioner, which superimposes the anastomosis and obscures its true morphology. Therefore, it may be recommended in cases of ambiguous angiographic findings to perform a quantitative coronary angiography using the thrombolysis in myocardial infarction (TIMI) flow grade classification (thrombolysis in myocardial infarction angiographic core).
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References
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- Klima U, Maringka M, Bagaev E, Kirschner CM, Haverich A. Total magnetic vascular coupling for arterial revscularization J Thorac Cardiovasc Surg 2004;127:602-603.[Free Full Text]
- Klima U, Falk V, Maringka M, et al. Magnetic vascular coupling for distal anastomosis in coronary artery bypass graftinga multicenter trial. J Thor Cardiovasc Surg 2003;126:1568-1574.[Abstract/Free Full Text]
- Anderson HV, McNatt J, Clubb FJ, et al. Platelet inhibition reduces cyclic flow variations and neointimal proliferation in normal and hypercholesterolemic-atherosclerotic canine coronary arteries Circulation 2001;104(19):2331-2337.[Abstract/Free Full Text]
- Gibson M, Murphy SA, Jeffrey J, Popma JJ. Insights into the pathophysiology of acute ischemic syndromes using the TIMI flow grade, TIMI frame count, and TIMI myocardial perfusion grade.. 2nd ed.. Totowa, NJ: Humana Press; 2002Management of acute coronary syndromes, 95–118..
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Abstract
Introduction
