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Left Circumflex Coronary-to-Pulmonary Artery Fistula as the Exclusive Collateral to the Occluded Left Anterior Descending Artery
CLINICAL SPOTLIGHT
Heart, Lung and Circulation (2014) 23, e1–e3 1443-9506/04/$36.00 http://dx.doi.org/10.1016/j.hlc.2013.05.642
Left Circumflex Coronary-to-Pulmonary Artery Fistula as the Exclusive Collateral to the Occluded Left Anterior Descending Artery H.-T. Yi, MDa,b, H.-C. Lai, MD, PhDa,b, H. Hsu, MDa, W.-L. Lee, MD, PhDa,b, K.-Y. Wang, MDa,c, M.-S. Chiang, MDa,b, T.-J. Liu, MD, PhDa,b* a
Cardiovascular Center and Department of Anesthesiology, Taichung Veterans General Hospital, Taiwan Institute of Clinical Medicine, Cardiovascular Research Center, Department of Medicine and Department of Surgery, National Yang Ming University School of Medicine, Taipei, Taiwan c Department of Medicine, Chung-Shan Medical University, Taichung, Taiwan b
Received 18 August 2012; received in revised form 4 April 2013; accepted 19 May 2013; online published-ahead-of-print 19 June 2013
A 64 year-old male presented with a five month history of effort angina. Non-invasive studies demonstrated preserved left ventricular function and a modest stress-induced myocardial perfusion defect at the anterior wall. Coronary angiography revealed occlusion of the proximal left anterior descending coronary artery with its distal segment well supplied by collaterals branching from a left circumflex-to-main pulmonary artery fistula. The occluded left anterior descending coronary artery was recanalised by percutaneous interventions, the collaterals vanished immediately, and the patient lived free of symptoms for the following five months. Keywords
Coronary Occlusion Fistula Collateral
Introduction Coronary arteriovenous (AV) fistula is a congenital coronary anomaly that diverts blood flow from the mainstream artery thereby resulting in hypo-perfusion and possible ischaemia of the downstream myocardium [1–3]. Here we report a patient in whom a left circumflex coronary artery (LCx)-main pulmonary artery (PA) fistula conversely played a favourable role in providing exclusive collateral blood supply to an occluded left anterior descending artery (LAD). Hence, though conventionally categorised as an unfavourable congenital anomaly, coronary AV fistula may paradoxically behave as an endogenous bypass graft to a neighbouring occluded coronary artery, which in turn preserves viability of that otherwise hypo-perfused myocardial territory.
Case Report A 64 year-old hypertensive male presented with effort angina for five months. Serial resting 12-lead ECGs were
unrevealing. Echocardiography demonstrated normal left ventricular systolic function. A treadmill ECG was inconclusive due to an inadequate maximal heart rate response. However thallium-201 dipyridamole-stressed myocardial perfusion scintigraphy disclosed a modest reversible defect at the apical and anteroseptal regions of the left ventricle (Fig. 1). Coronary angiography demonstrated a 2.5-cm occluded segment at the proximal LAD, with its distal territory well supplied by Rentrop grade III collaterals from the downstream branches of a coronary arteriovenous fistula, which connected the first obtuse marginal branch of the LCx with main PA and then the LAD proper at just beyond the take-off of the first diagonal artery (Fig. 2A and supplementary videos 1 & 2). The occluded LAD was opened and stented using standard antegrade interventional procedures, and the collaterals from coronary fistula to LAD immediately vanished (Fig. 2B and supplementary videos 3 & 4). The patient was discharged on the second day uneventfully. He lived free of any more angina for the following six months and a repeat treadmill ECG was well tolerated showing negative findings.
* Corresponding author at: Cardiovascular Center, Taichung Veterans General Hospital, 160, Section 3, Taichung Harbor Road, Taichung 407, Taiwan. Tel.: +886 4 23592525x3124; fax: +886 4 23599257., Email: [email protected] © 2013 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Published by Elsevier Inc. All rights reserved.
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H-T Yi et al.
Figure 1 Thallium-201 myocardial perfusion scintigrams in the short- (left) and horizontal long (right) planes. (A) Fiveminutes after dipyridamole-induced stress. There was a modest perfusion defect in the anteroseptal and apical regions (arrows) of left ventricle, suggesting reduced blood supply to the LAD territory. (B) Four hours after redistribution. The perfusion defect recovered completely, indicating this myocardial zone remained viable.
Discussion Coronary AV fistulas typically shunt blood away from the native artery thereby potentially causing underperfusion of the downstream myocardium [2,3]. When superimposed with atherosclerotic occlusion of a neighbouring coronary artery, the resulting myocardial ischaemia could potentially be even more severe [1]. In contrast, our patient with both of the above abnormalities, the coronary-pulmonary artery fistula drained blood flow out of the relatively minor LCx to the dominant yet occluded LAD via prominent collateral channels and provided sufficient perfusion to that vascular territory. This fact indicates that a coronary AV fistula may have a ‘Robin Hood’ like effect, which steals blood from a rich coronary vessel to provide flow to a poor one and in turn salvages that otherwise hypo-perfused myocardial zone. Coronary fistula-originated collateral channels connecting proximal to distal segment of an occluded LAD have been twice reported previously [4,5]. However, in those studies the patients still suffered either acute or undetected myocardial infarction resulting in significant left ventricular dysfunction, suggesting the collaterals from those LAD-to-LAD fistulas did not open in sufficient time to prevent ischaemic
injury. In contrast, although our patient also had an occluded LAD, he presented with mild symptoms, a modest stress-induced myocardial perfusion defect and preserved left ventricular function, suggesting well established collaterals from the LCx-to-main PA fistula prior to the LAD occlusion. These differences in clinical presentations highlight antecedent functional collateral development as the key prerequisite for these fistula-derived collaterals to effectively prevent ischaemia-related myocardial injury. Conventional patterns of collateral pathways include only intra- and inter-coronary communicating channels [6,7] but not coronary fistulas. The current report provides evidence for coronary fistula as another potential collateral source, which could provide supplementary blood supply to an adjacent occluded coronary artery and preserve viability at that vascular territory. In conclusion, a coronary AV fistula may act as the exclusive collateral channel to the distal portion of an adjacent occluded coronary artery and preserve its downstream myocardium. Thus, management of such coronary abnormalities should be on a case-by-case basis, as not all coronary fistulas are harmful but some of them might serve as an endogenous bypass graft to an occluded vessel segment in the future.
Coronary fistula as collaterals
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Figure 2 Coronary angiograms (A) baseline. Right anterior oblique (left upper panel) and left anterior oblique (right upper panel) projections demonstrated the occluded proximal LAD (arrowheads) and the LCx-main PA coronary fistula sending the exclusive collaterals to middle LAD (arrows). Lower panels illustrate by schematic drawings the overall route of the coronary AV fistula originating from the first obtuse marginal branch of LCx (point a) draining into main PA (point b) and then via collateral channels to middle LAD at beyond the first diagonal branch (point c). (B) immediately after stenting of the occluded proximal LAD. The LCx-main PA fistula (arrows) remained there, whereas the collateral channels extending from this fistula to mid-LAD vanished.
Appendix A. Supplementary data Supplementary data associated with this article can be found, in the online version, at http://dx.doi.org/10.1016/ j.hlc.2013.05.642.
References [1] Mukai H, Minemawari Y, Hanawa N, Mita T, Motoe M, Nakata T. Coronary stenosis and steal phenomenon in coronary-pulmonary fistula—assessment with stress thallium tomography after coronary angioplasty and fistulectomy. Jpn Circ J 1993;57:1021–6.
[2] Sherwood MC, Rockenmacher S, Colan SD, Geva T. Prognostic significance of clinically silent coronary artery fistulas. Am J Cardiol 1999;83:407–11. [3] Mangukia CV. Coronary artery fistula. Ann Thorac Surg 2012;93:2084–92. [4] Abaci A, Erbas G, Turkoglu S. Cardiovascular flashlight. Coronary fistulas are not always bad: coronary artery to coronary artery fistula as a very unusual collateral pathway. Eur Heart J 2010;31:1300. [5] Komatsu S, Hirayama A, Sato Y, Kodama K. Coronary-pulmonary fistula serving as a collateral source to the occluded coronary artery in a patient with myocardial infarction. Int J Cardiol 2007;115:408–9. [6] Levin DC. Pathways and functional significance of the coronary collateral circulation. Circulation 1974;50:831–7. [7] Nishimura S, Ohshima S, Kato K, Daida H, Nishiyama S, Nakanishi S, et al. Coronary collaterals in patients with total obstruction of the proximal left anterior descending artery: their pathways and functional significance. J Cardiogr 1985;15:969–79.
Heart, Lung and Circulation (2014) 23, e1–e3 1443-9506/04/$36.00 http://dx.doi.org/10.1016/j.hlc.2013.05.642
Left Circumflex Coronary-to-Pulmonary Artery Fistula as the Exclusive Collateral to the Occluded Left Anterior Descending Artery H.-T. Yi, MDa,b, H.-C. Lai, MD, PhDa,b, H. Hsu, MDa, W.-L. Lee, MD, PhDa,b, K.-Y. Wang, MDa,c, M.-S. Chiang, MDa,b, T.-J. Liu, MD, PhDa,b* a
Cardiovascular Center and Department of Anesthesiology, Taichung Veterans General Hospital, Taiwan Institute of Clinical Medicine, Cardiovascular Research Center, Department of Medicine and Department of Surgery, National Yang Ming University School of Medicine, Taipei, Taiwan c Department of Medicine, Chung-Shan Medical University, Taichung, Taiwan b
Received 18 August 2012; received in revised form 4 April 2013; accepted 19 May 2013; online published-ahead-of-print 19 June 2013
A 64 year-old male presented with a five month history of effort angina. Non-invasive studies demonstrated preserved left ventricular function and a modest stress-induced myocardial perfusion defect at the anterior wall. Coronary angiography revealed occlusion of the proximal left anterior descending coronary artery with its distal segment well supplied by collaterals branching from a left circumflex-to-main pulmonary artery fistula. The occluded left anterior descending coronary artery was recanalised by percutaneous interventions, the collaterals vanished immediately, and the patient lived free of symptoms for the following five months. Keywords
Coronary Occlusion Fistula Collateral
Introduction Coronary arteriovenous (AV) fistula is a congenital coronary anomaly that diverts blood flow from the mainstream artery thereby resulting in hypo-perfusion and possible ischaemia of the downstream myocardium [1–3]. Here we report a patient in whom a left circumflex coronary artery (LCx)-main pulmonary artery (PA) fistula conversely played a favourable role in providing exclusive collateral blood supply to an occluded left anterior descending artery (LAD). Hence, though conventionally categorised as an unfavourable congenital anomaly, coronary AV fistula may paradoxically behave as an endogenous bypass graft to a neighbouring occluded coronary artery, which in turn preserves viability of that otherwise hypo-perfused myocardial territory.
Case Report A 64 year-old hypertensive male presented with effort angina for five months. Serial resting 12-lead ECGs were
unrevealing. Echocardiography demonstrated normal left ventricular systolic function. A treadmill ECG was inconclusive due to an inadequate maximal heart rate response. However thallium-201 dipyridamole-stressed myocardial perfusion scintigraphy disclosed a modest reversible defect at the apical and anteroseptal regions of the left ventricle (Fig. 1). Coronary angiography demonstrated a 2.5-cm occluded segment at the proximal LAD, with its distal territory well supplied by Rentrop grade III collaterals from the downstream branches of a coronary arteriovenous fistula, which connected the first obtuse marginal branch of the LCx with main PA and then the LAD proper at just beyond the take-off of the first diagonal artery (Fig. 2A and supplementary videos 1 & 2). The occluded LAD was opened and stented using standard antegrade interventional procedures, and the collaterals from coronary fistula to LAD immediately vanished (Fig. 2B and supplementary videos 3 & 4). The patient was discharged on the second day uneventfully. He lived free of any more angina for the following six months and a repeat treadmill ECG was well tolerated showing negative findings.
* Corresponding author at: Cardiovascular Center, Taichung Veterans General Hospital, 160, Section 3, Taichung Harbor Road, Taichung 407, Taiwan. Tel.: +886 4 23592525x3124; fax: +886 4 23599257., Email: [email protected] © 2013 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Published by Elsevier Inc. All rights reserved.
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H-T Yi et al.
Figure 1 Thallium-201 myocardial perfusion scintigrams in the short- (left) and horizontal long (right) planes. (A) Fiveminutes after dipyridamole-induced stress. There was a modest perfusion defect in the anteroseptal and apical regions (arrows) of left ventricle, suggesting reduced blood supply to the LAD territory. (B) Four hours after redistribution. The perfusion defect recovered completely, indicating this myocardial zone remained viable.
Discussion Coronary AV fistulas typically shunt blood away from the native artery thereby potentially causing underperfusion of the downstream myocardium [2,3]. When superimposed with atherosclerotic occlusion of a neighbouring coronary artery, the resulting myocardial ischaemia could potentially be even more severe [1]. In contrast, our patient with both of the above abnormalities, the coronary-pulmonary artery fistula drained blood flow out of the relatively minor LCx to the dominant yet occluded LAD via prominent collateral channels and provided sufficient perfusion to that vascular territory. This fact indicates that a coronary AV fistula may have a ‘Robin Hood’ like effect, which steals blood from a rich coronary vessel to provide flow to a poor one and in turn salvages that otherwise hypo-perfused myocardial zone. Coronary fistula-originated collateral channels connecting proximal to distal segment of an occluded LAD have been twice reported previously [4,5]. However, in those studies the patients still suffered either acute or undetected myocardial infarction resulting in significant left ventricular dysfunction, suggesting the collaterals from those LAD-to-LAD fistulas did not open in sufficient time to prevent ischaemic
injury. In contrast, although our patient also had an occluded LAD, he presented with mild symptoms, a modest stress-induced myocardial perfusion defect and preserved left ventricular function, suggesting well established collaterals from the LCx-to-main PA fistula prior to the LAD occlusion. These differences in clinical presentations highlight antecedent functional collateral development as the key prerequisite for these fistula-derived collaterals to effectively prevent ischaemia-related myocardial injury. Conventional patterns of collateral pathways include only intra- and inter-coronary communicating channels [6,7] but not coronary fistulas. The current report provides evidence for coronary fistula as another potential collateral source, which could provide supplementary blood supply to an adjacent occluded coronary artery and preserve viability at that vascular territory. In conclusion, a coronary AV fistula may act as the exclusive collateral channel to the distal portion of an adjacent occluded coronary artery and preserve its downstream myocardium. Thus, management of such coronary abnormalities should be on a case-by-case basis, as not all coronary fistulas are harmful but some of them might serve as an endogenous bypass graft to an occluded vessel segment in the future.
Coronary fistula as collaterals
e3
Figure 2 Coronary angiograms (A) baseline. Right anterior oblique (left upper panel) and left anterior oblique (right upper panel) projections demonstrated the occluded proximal LAD (arrowheads) and the LCx-main PA coronary fistula sending the exclusive collaterals to middle LAD (arrows). Lower panels illustrate by schematic drawings the overall route of the coronary AV fistula originating from the first obtuse marginal branch of LCx (point a) draining into main PA (point b) and then via collateral channels to middle LAD at beyond the first diagonal branch (point c). (B) immediately after stenting of the occluded proximal LAD. The LCx-main PA fistula (arrows) remained there, whereas the collateral channels extending from this fistula to mid-LAD vanished.
Appendix A. Supplementary data Supplementary data associated with this article can be found, in the online version, at http://dx.doi.org/10.1016/ j.hlc.2013.05.642.
References [1] Mukai H, Minemawari Y, Hanawa N, Mita T, Motoe M, Nakata T. Coronary stenosis and steal phenomenon in coronary-pulmonary fistula—assessment with stress thallium tomography after coronary angioplasty and fistulectomy. Jpn Circ J 1993;57:1021–6.
[2] Sherwood MC, Rockenmacher S, Colan SD, Geva T. Prognostic significance of clinically silent coronary artery fistulas. Am J Cardiol 1999;83:407–11. [3] Mangukia CV. Coronary artery fistula. Ann Thorac Surg 2012;93:2084–92. [4] Abaci A, Erbas G, Turkoglu S. Cardiovascular flashlight. Coronary fistulas are not always bad: coronary artery to coronary artery fistula as a very unusual collateral pathway. Eur Heart J 2010;31:1300. [5] Komatsu S, Hirayama A, Sato Y, Kodama K. Coronary-pulmonary fistula serving as a collateral source to the occluded coronary artery in a patient with myocardial infarction. Int J Cardiol 2007;115:408–9. [6] Levin DC. Pathways and functional significance of the coronary collateral circulation. Circulation 1974;50:831–7. [7] Nishimura S, Ohshima S, Kato K, Daida H, Nishiyama S, Nakanishi S, et al. Coronary collaterals in patients with total obstruction of the proximal left anterior descending artery: their pathways and functional significance. J Cardiogr 1985;15:969–79.