Ann Thorac Surg 2001;71:352-355
© 2001 The Society of Thoracic Surgeons
Case report
Stunned myocardium after off-pump coronary artery bypass grafting
Herko Grubitzsch, MDa,
Knut Ansorge, MDa,
Hans-Georg Wollert, MDa,
Lothar Eckel, MDa
a Clinic of Thoracic and Cardiovascular Surgery, Heart and Diabetes Centre Mecklenburg-Vorpommern, Karlsburg, Germany
Accepted for publication May 23, 2000.
Address reprint requests to Dr Grubitzsch, Herz- und Diabeteszentrum Mecklenburg-Vorpommern, Klinikum Karlsburg, Klinik für Herz-, Thorax- und Gefäßchirurgie, Greifswalder Str 11 A, D-17495 Karlsburg, Germany
e-mail: grubitzsch{at}t-online.de
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Abstract
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Off-pump coronary artery bypass grafting is increasingly performed. Because these procedures are associated with temporary myocardial ischemia, there is a risk of ischemia-related complications. We report two cases of myocardial stunning after off-pump coronary artery bypass grafting using the Octopus tissue stabilizer. On the basis of our experiences, means to prevent stunning are discussed.
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Introduction
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Stunned myocardium is defined as postischemic contractile dysfunction of viable myocardium [1]. After characterization of this phenomenon in experimental models, clinical situations in which stunning occurs were reported [2]. Apart from delayed recovery of myocardial function after angioplastic or thrombolytic therapy for myocardial infarction, stunned myocardium was also postulated occurring after cardiopulmonary bypass [3].
Recently, various techniques of off-pump coronary artery bypass grafting were introduced into clinical practice. One characteristic feature of these operations is temporary occlusion of native coronary vessels bearing the risk of ischemic or even postischemic ventricular dysfunction. However, the occurrence of myocardial stunning in this setting has not been described. We report on 2 patients in which temporary left ventricular dysfunction developed after off-pump coronary revascularization.
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Case reports
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Patient 1
A 55-year-old female patient presented with stable angina (Candian Cardiovascular Study [CCS] II) due to an approximately 80% stenotic lesion involving the left anterior descending (LAD) and the first diagonal branch of the left coronary artery. The other coronary vessels were not diseased. There was no left ventricular dysfunction. Revascularization was performed by grafting the left internal thoracic artery to LAD and a saphenous vein graft to the first diagonal branch using the Octopus tissue stabilizer (Medtronic Inc, Minneapolis, MN). The intraoperative course was uneventful. For temporary coronary artery occlusion, tourniquets placed on perivascular Prolene (Ethicon, Norderstedt, Germany) stitches proximal and distal of the incision were used. For de-airing the grafts and coronary vessels backbleeding was applied. Although temporary LAD occlusion was prolonged due to bleeding out of a septal branch (no shunt; occlusion time; see Table 1) the electrocardiogram showed no signs of ischemia. In addition, continuous left atrial pressure monitoring, which is a sensitive measurement of left ventricular performance [4], did not reveal contractile dysfunction. During embracing or luxation of the heart as well as during temporary diagonal branch occlusion there was also no evidence of relevant ischemia or left ventricular dysfunction. About 3 hours postoperatively low cardiac output followed by recurrent ventricular fibrillation occurred. By reexploration, palpation showed normal graft pulsation. Graft spasm and pericardial tamponade were excluded. Laboratory tests revealed only a slight elevation of cardiac enzymes (creatine phosphokinase, 16.6 µkat/L; myocardial creatine phosphokinase, 1.8 µkat/L; about 8 hours postoperatively [normal values: creatine phosphokinase: 0.00–3.15 µkat/L; myocardial creatine phosphokinase: 0.00–0.40 µkat/L]) most probably due to repeated electrical defibrillations. Coronary angiogram, performed at catheterization laboratory, showed patent bypass grafts and correct anastomotic sites (Fig 1). The status of the native coronary arteries remained unchanged. However, left ventricular function was depressed due to an akinetic apical anterior wall as assessed by transesophageal echocardiogram. For inotropic support, continuous adrenaline infusion was necessary. Amiodarone was administered for antiarrhythmic treatment. After hemodynamic stabilization the patient left the intensive care unit without inotropic support on the fourth postoperative day. Before hospital discharge on 14th postoperative day the echocardiogram showed normal left ventricular function without regional wall motion abnormalities.
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Fig 1. Postoperative coronary angiogram of patient 1. Patent bypass grafts and good quality anastomotic sites are shown. The native coronary arteries remained unchanged compared to the preoperative angiogram. (A) Left internal thoracic artery to left anterior descending coronary artery. (The seeming radiolucency of the left anterior descending coronary artery distal to the anastomosis is an artifact that is not visible at the coronary angiogram film.) (B) Saphenous vein graft to the first diagonal branch.
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Patient 2
A 68-year-old man presented with stable angina (CCS II) because of coronary two-vessel disease with a proximal stenosis (70%) of the LAD and a medial stenosis (50%) of the right coronary artery. The circumflex branch was not involved. Left ventricular function was normal. By means of the Octopus system the left and the right internal thoracic arteries were used for complete arterial revascularization of the LAD and right coronary artery, respectively. As in patient 1 the intraoperative course was uneventful. Although no shunt was used there was no evidence of ischemia or left ventricular dysfunction by electrocardiogram and left atrial pressure monitoring. The patient left the operating room without any inotropic support. However, after about 5 hours low cardiac output developed. Thus, reexploration was performed about 7 hours postoperatively, but pericardial tamponade was excluded and graft function was adequate. Cardiac enzymes were not significantly elevated (creatine phosphokinase, 2.38 µkat/L; myocardial creatine phosphokinase, 0.27 µkat/L; about 10 hours postoperatively). Coronary angiogram showed patent bypass grafts and good quality anastomotic sites. According to transesophageal echocardiogram the depressed left ventricular contractility mainly resulted from dyskinesia of the interventricular septum and hypokinesia of the apex. For circulatory support intraaortic balloon pumping and continuous catecholamine infusion for 24 and 65 hours, respectively, were necessary. On fifth postoperative day the patient left the intensive care unit. Echocardiography before hospital discharge on the 17th postoperative day showed normal left ventricular function without compromised regional kinetics.
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Comment
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In 2 of 102 off-pump coronary artery bypass grafting procedures we have performed from January 1998 to December 1999 using the Octopus system severe left ventricular dysfunction developed after operation. Interestingly, during temporary coronary artery occlusion no signs of myocardial ischemia or left ventricular dysfunction were monitored in either patient. Both patients left the operating room without inotropic support, but developed low cardiac output consecutively. Because the postoperative coronary angiogram showed patent bypass grafts and unchanged native coronary vessels, the only ischemic event being able to trigger contractile dysfunction was temporary occlusion of the coronary arteries while performing the anastomosis. According to this the region of worst depression of contractility corresponded to the perfusion area of the occluded coronary artery (patient 1: akinetic anterior wall to LAD occlusion; patient 2: dyskinetic interventricular septum, hypokinetic apex to LAD occlusion). As shown by echocardiography left ventricular function recovered completely within 14 days. Thus, as in similar clinical situations [2, 3] this reversible postischemic contractile dysfunction seems to have its pathophysiologic background in myocardial stunning.
Although inotropics or mechanical assist devices can support the acutely failing heart sufficiently, the ultimate objective must be to prevent ventricular dysfunction. One approach could be ischemic preconditioning [5], which can be achieved by repetitive short-time occlusion and reperfusion of the coronary vessel before performing anastomosis. However, in the reported patients we did not observe ST-segment depression or elevation after coronary artery occlusion, which usually indicates the necessity of preconditioning. Furthermore, in a clinical setting of minimally invasive coronary artery bypass grafting transient ischemia did not limit subsequent ischemic regional dysfunction [6]. What we have learned is that the avoidance of ischemia is most important to obtain superior safety in off-pump coronary artery bypass grafting. Therefore, we recommend the use of intracoronary shunts if duration of temporary coronary artery occlusion exceeds 15 minutes. Because of the potential risk of endothelium alteration, shunts should not be applied in every off-pump coronary artery bypass grafting procedure.
In conclusion, in performing off-pump coronary artery bypass grafting one has to consider the potential risk of postischemic contractile dysfunction. Therefore, thorough monitoring of ischemic parameters as well as shortening of ischemic periods must be pivotal issues in these procedures.
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References
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Braunwald E., Kloner R.A. The stunned myocardium: prolonged postischemic ventricular dysfunction. Circulation 1982;66:1146-1149.[Abstract/Free Full Text]
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Bolli R. Myocardial "stunning" in man. Circulation 1992;86:1671-1691.[Free Full Text]
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Kloner R.A., Przyklenk K., Kay G.L. Clinical evidence for stunned myocardium after coronary artery bypass surgery. J Card Surg 1994;9(suppl):397-402.[Medline]
-
Grubitzsch H., Ansorge K., Wollert H.G., Eckel L. Hemodynamic monitoring in patients undergoing off-pump coronary artery bypass grafting using the Octopus tissue stabilizer—left atrial pressure as a gold standard. J Cardiothorac Vasc Anesth 2000;14:105-106.[Medline]
-
Alkhulaifi A.M., Jenkins D.P., Pugsley W.B., Treasure T. Ischaemic preconditioning and cardiac surgery. Eur J Cardiothorac Surg 1996;10:792-798.[Abstract]
-
Malkowski M.J., Kramer C.M., Parvizi S.T., et al. Transient ischemia does not limit subsequent ischemic regional dysfunction in humans: a transesophageal echocardiographic study during minimally invasive coronary artery bypass surgery. J Am Coll Cardiol 1998;31:1035-1039.[Abstract/Free Full Text]
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Abstract
Introduction
