The unstoppable heart: an aortocoronary fistula in coronary artery bypass grafting

The unstoppable heart: an aortocoronary fistula in coronary artery bypass grafting Abstract This case report describes a coronary bypass surgery case in which cardioplegic arrest was impossible due to an aortacoronary fistula that was visualized using 3-dimensional computer tomography (CT) angiography postoperatively. Aortacoronary fistulas are protective in coronary artery disease but can severely complicate cardiac surgery and might require CT imaging in the preoperative workup. Extracardiac fistula , Coronary artery bypass grafting , Cardioplegia INTRODUCTION Coronary collaterals may develop in patients with coronary artery disease (CAD) and can reduce mortality compared to patients with no collaterals [1]. However, extracardiac collaterals, such as aortocoronary fistulas (ACFs), can complicate cardiac surgery. We describe a case with a large ACF that made cardioplegic arrest impossible during coronary artery bypass grafting (CABG). CASE PRESENTATION A 61-year-old man was referred to our department with a 99% left main stenosis and a chronic total occlusion of the right coronary artery and left circumflex artery. Despite the poor coronary status, echocardiography revealed a normal left ventricular ejection fraction, and he was considered for CABG. After routine cannulation, crystalloid cardioplegia was given antegradely via the aortic root and retrogradely via the coronary sinus; however, cardioplegic arrest could not be achieved. A left ventricular vent and a second aortic cross-clamp were placed, but the heart would not stop beating despite 3 l of cardioplegia. We hypothesized that cardioplegic arrest was out of the question because of extracardiac collateralization. After cooling to 28°C, the bypasses were performed on a fibrillating heart. The anastomoses were impeded by high-pulsatile backflow. The graft formula was as follows: left internal thoracic artery (LITA) − left anterior descending artery (LAD), right internal thoracic artery (RITA) − LITA − anterolateral branch (AL) and saphenous vein − obtuse marginal. Weaning from cardiopulmonary bypass was impossible because of persistent hypotension, and temporary intra-aortic balloon pump and venoarterial extracorporeal life support were necessary to recover from the long period of ventricular fibrillation and stunning. Left ventricular ejection fraction recovered postoperatively, and the coronary angiogram showed patent anastomoses. Five days after surgery, the patient was weaned from extracorporeal life support with the support of levosimendan, and the day after the balloon pump was removed. To confirm the presence of extracardiac coronary collaterals, a multidetector computer tomography (CT) angiography of the heart was performed. Three-dimensional augmentation using the C-station and Vesalius 3D software (PS-Medtech, Amsterdam, Netherlands) objectivized a large collateral originating from the proximal descending aorta, curving its way posterior of the right pulmonary artery, then anterior of the left pulmonary veins, across the lateral wall of the left atrium to eventually anastomose with the circumflex artery between the obtuse marginal and the posterolateral branch (Fig. 1). Figure 1. View largeDownload slide Multidetector computer tomography angiography derived 3-dimensional image showing the coronary anatomy, bypass grafts and collateral artery. (A) Lateral view of the heart showing the aortocoronary collateral originating from the descending aorta and anastomosing with the circumflex artery. (B) Posterior view to highlight the collateral between the left pulmonary artery and the right pulmonary artery and anterior of the right pulmonary veins. AL: anterolateral branch; CS: coronary sinus; fRITA: free right internal thoracic artery; LA: left atrium; LAD: left anterior descending artery; LCx: left circumflex artery; LITA: left internal thoracic artery; LIPV: left inferior pulmonary vein; LPA: left pulmonary artery; LSPV: left superior pulmonary vein; OM: obtuse marginal artery; RIPV: right inferior pulmonary vein; RPA: right pulmonary artery; RSPV: right superior pulmonary vein; VCS: vena cava superior; VSM: vena saphena magna Figure 1. View largeDownload slide Multidetector computer tomography angiography derived 3-dimensional image showing the coronary anatomy, bypass grafts and collateral artery. (A) Lateral view of the heart showing the aortocoronary collateral originating from the descending aorta and anastomosing with the circumflex artery. (B) Posterior view to highlight the collateral between the left pulmonary artery and the right pulmonary artery and anterior of the right pulmonary veins. AL: anterolateral branch; CS: coronary sinus; fRITA: free right internal thoracic artery; LA: left atrium; LAD: left anterior descending artery; LCx: left circumflex artery; LITA: left internal thoracic artery; LIPV: left inferior pulmonary vein; LPA: left pulmonary artery; LSPV: left superior pulmonary vein; OM: obtuse marginal artery; RIPV: right inferior pulmonary vein; RPA: right pulmonary artery; RSPV: right superior pulmonary vein; VCS: vena cava superior; VSM: vena saphena magna Apart from a brief episode of atrial fibrillation, postoperative recovery was uneventful. Twenty-six days after surgery, our patient was discharged to a rehabilitation clinic with a fully recovered left ventricular ejection fraction. COMMENT Extracardiac collaterals are coronary anomalies that are rarely encountered in healthy individuals. Non-functional anastomoses between coronary arteries and bronchial arteries are believed to be present at birth and remain silent in most cases. The enlargement of these vessels due to changes in pressure equilibrium may result in functional ACFs [2], which might lead to angina in case of the coronary steal phenomenon. In patients with CAD, they are more abundant [1] and have shown to be protective and reduce mortality. In case of chronic total occlusion, extracardiac fistulas might be able to perfuse the occluded coronary, thereby preventing myocardial infarction and preserving ventricular contractility. The preoperative angiography failed to reveal the ACF due to the proximal occlusion of the circumflex artery. As in the preoperative workup of revascularization of chronic total occlusions [3], Lee et al. [2] have shown that multidetector CT is a reliable and non-invasive tool for detecting collaterals. Three-dimensional augmentation might aid in further unravelling the coronary anatomy and their anomalies. This case has proved that extracardiac collateralization of the coronaries can significantly complicate cardiac surgery. When experiencing severe backflow and difficulties sustaining cardioplegia, one must always question the presence of extracardiac anastomoses [4]. Off-pump or pump-assisted beating heart surgery can be used as an alternative to prevent cooling and ventricular stunning due to fibrillation. The case is an opportune reminder of how even the lowest risk case can be complicated by unexpected findings. In patients with severe CAD or occluded vessels but preserved left ventricular contractility, extracardiac anastomoses must be expected and a contrast-enhanced CT scan should be considered in the preoperative workup of CABG. Conflict of interest: none declared. REFERENCES 1 Meier P, Hemingway H, Lansky AJ, Knapp G, Pitt B, Seiler C. The impact of the coronary collateral circulation on mortality: a meta-analysis. Eur Heart J  2012; 33: 614– 21. Google Scholar CrossRef Search ADS PubMed  2 Lee ST, Kim SY, Hur G, Hwang YJ, Kim YH, Seo JW et al.   Coronary-to-bronchial artery fistula: demonstration by 64-multidetector computed tomography with retrospective electrocardiogram-gated reconstructions. J Comput Assist Tomogr  2008; 32: 444– 7. Google Scholar CrossRef Search ADS PubMed  3 Opolski MP, Achenbach S. CT angiography for revascularization of CTO: crossing the borders of diagnosis and treatment. JACC Cardiovasc Imaging  2015; 8: 846– 58. Google Scholar CrossRef Search ADS PubMed  4 Goetti R, Candinas R, Leschka S, Hoffmann U, Alkadhi H. IMAGE CARDIO MED: bronchocoronary collateral circulation: clinical utility of cardiac computed tomography. Circulation  2010; 121: 180– 1. Google Scholar CrossRef Search ADS PubMed  © The Author(s) 2018. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved. This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/about_us/legal/notices) http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Interactive CardioVascular and Thoracic Surgery Oxford University Press

The unstoppable heart: an aortocoronary fistula in coronary artery bypass grafting

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Oxford University Press
Copyright
© The Author(s) 2018. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.
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1569-9293
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Abstract

Abstract This case report describes a coronary bypass surgery case in which cardioplegic arrest was impossible due to an aortacoronary fistula that was visualized using 3-dimensional computer tomography (CT) angiography postoperatively. Aortacoronary fistulas are protective in coronary artery disease but can severely complicate cardiac surgery and might require CT imaging in the preoperative workup. Extracardiac fistula , Coronary artery bypass grafting , Cardioplegia INTRODUCTION Coronary collaterals may develop in patients with coronary artery disease (CAD) and can reduce mortality compared to patients with no collaterals [1]. However, extracardiac collaterals, such as aortocoronary fistulas (ACFs), can complicate cardiac surgery. We describe a case with a large ACF that made cardioplegic arrest impossible during coronary artery bypass grafting (CABG). CASE PRESENTATION A 61-year-old man was referred to our department with a 99% left main stenosis and a chronic total occlusion of the right coronary artery and left circumflex artery. Despite the poor coronary status, echocardiography revealed a normal left ventricular ejection fraction, and he was considered for CABG. After routine cannulation, crystalloid cardioplegia was given antegradely via the aortic root and retrogradely via the coronary sinus; however, cardioplegic arrest could not be achieved. A left ventricular vent and a second aortic cross-clamp were placed, but the heart would not stop beating despite 3 l of cardioplegia. We hypothesized that cardioplegic arrest was out of the question because of extracardiac collateralization. After cooling to 28°C, the bypasses were performed on a fibrillating heart. The anastomoses were impeded by high-pulsatile backflow. The graft formula was as follows: left internal thoracic artery (LITA) − left anterior descending artery (LAD), right internal thoracic artery (RITA) − LITA − anterolateral branch (AL) and saphenous vein − obtuse marginal. Weaning from cardiopulmonary bypass was impossible because of persistent hypotension, and temporary intra-aortic balloon pump and venoarterial extracorporeal life support were necessary to recover from the long period of ventricular fibrillation and stunning. Left ventricular ejection fraction recovered postoperatively, and the coronary angiogram showed patent anastomoses. Five days after surgery, the patient was weaned from extracorporeal life support with the support of levosimendan, and the day after the balloon pump was removed. To confirm the presence of extracardiac coronary collaterals, a multidetector computer tomography (CT) angiography of the heart was performed. Three-dimensional augmentation using the C-station and Vesalius 3D software (PS-Medtech, Amsterdam, Netherlands) objectivized a large collateral originating from the proximal descending aorta, curving its way posterior of the right pulmonary artery, then anterior of the left pulmonary veins, across the lateral wall of the left atrium to eventually anastomose with the circumflex artery between the obtuse marginal and the posterolateral branch (Fig. 1). Figure 1. View largeDownload slide Multidetector computer tomography angiography derived 3-dimensional image showing the coronary anatomy, bypass grafts and collateral artery. (A) Lateral view of the heart showing the aortocoronary collateral originating from the descending aorta and anastomosing with the circumflex artery. (B) Posterior view to highlight the collateral between the left pulmonary artery and the right pulmonary artery and anterior of the right pulmonary veins. AL: anterolateral branch; CS: coronary sinus; fRITA: free right internal thoracic artery; LA: left atrium; LAD: left anterior descending artery; LCx: left circumflex artery; LITA: left internal thoracic artery; LIPV: left inferior pulmonary vein; LPA: left pulmonary artery; LSPV: left superior pulmonary vein; OM: obtuse marginal artery; RIPV: right inferior pulmonary vein; RPA: right pulmonary artery; RSPV: right superior pulmonary vein; VCS: vena cava superior; VSM: vena saphena magna Figure 1. View largeDownload slide Multidetector computer tomography angiography derived 3-dimensional image showing the coronary anatomy, bypass grafts and collateral artery. (A) Lateral view of the heart showing the aortocoronary collateral originating from the descending aorta and anastomosing with the circumflex artery. (B) Posterior view to highlight the collateral between the left pulmonary artery and the right pulmonary artery and anterior of the right pulmonary veins. AL: anterolateral branch; CS: coronary sinus; fRITA: free right internal thoracic artery; LA: left atrium; LAD: left anterior descending artery; LCx: left circumflex artery; LITA: left internal thoracic artery; LIPV: left inferior pulmonary vein; LPA: left pulmonary artery; LSPV: left superior pulmonary vein; OM: obtuse marginal artery; RIPV: right inferior pulmonary vein; RPA: right pulmonary artery; RSPV: right superior pulmonary vein; VCS: vena cava superior; VSM: vena saphena magna Apart from a brief episode of atrial fibrillation, postoperative recovery was uneventful. Twenty-six days after surgery, our patient was discharged to a rehabilitation clinic with a fully recovered left ventricular ejection fraction. COMMENT Extracardiac collaterals are coronary anomalies that are rarely encountered in healthy individuals. Non-functional anastomoses between coronary arteries and bronchial arteries are believed to be present at birth and remain silent in most cases. The enlargement of these vessels due to changes in pressure equilibrium may result in functional ACFs [2], which might lead to angina in case of the coronary steal phenomenon. In patients with CAD, they are more abundant [1] and have shown to be protective and reduce mortality. In case of chronic total occlusion, extracardiac fistulas might be able to perfuse the occluded coronary, thereby preventing myocardial infarction and preserving ventricular contractility. The preoperative angiography failed to reveal the ACF due to the proximal occlusion of the circumflex artery. As in the preoperative workup of revascularization of chronic total occlusions [3], Lee et al. [2] have shown that multidetector CT is a reliable and non-invasive tool for detecting collaterals. Three-dimensional augmentation might aid in further unravelling the coronary anatomy and their anomalies. This case has proved that extracardiac collateralization of the coronaries can significantly complicate cardiac surgery. When experiencing severe backflow and difficulties sustaining cardioplegia, one must always question the presence of extracardiac anastomoses [4]. Off-pump or pump-assisted beating heart surgery can be used as an alternative to prevent cooling and ventricular stunning due to fibrillation. The case is an opportune reminder of how even the lowest risk case can be complicated by unexpected findings. In patients with severe CAD or occluded vessels but preserved left ventricular contractility, extracardiac anastomoses must be expected and a contrast-enhanced CT scan should be considered in the preoperative workup of CABG. Conflict of interest: none declared. REFERENCES 1 Meier P, Hemingway H, Lansky AJ, Knapp G, Pitt B, Seiler C. The impact of the coronary collateral circulation on mortality: a meta-analysis. Eur Heart J  2012; 33: 614– 21. Google Scholar CrossRef Search ADS PubMed  2 Lee ST, Kim SY, Hur G, Hwang YJ, Kim YH, Seo JW et al.   Coronary-to-bronchial artery fistula: demonstration by 64-multidetector computed tomography with retrospective electrocardiogram-gated reconstructions. J Comput Assist Tomogr  2008; 32: 444– 7. Google Scholar CrossRef Search ADS PubMed  3 Opolski MP, Achenbach S. CT angiography for revascularization of CTO: crossing the borders of diagnosis and treatment. JACC Cardiovasc Imaging  2015; 8: 846– 58. Google Scholar CrossRef Search ADS PubMed  4 Goetti R, Candinas R, Leschka S, Hoffmann U, Alkadhi H. IMAGE CARDIO MED: bronchocoronary collateral circulation: clinical utility of cardiac computed tomography. Circulation  2010; 121: 180– 1. Google Scholar CrossRef Search ADS PubMed  © The Author(s) 2018. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved. This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/about_us/legal/notices)

Journal

Interactive CardioVascular and Thoracic SurgeryOxford University Press

Published: Jun 2, 2018

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