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Giant Coronary Aneurysms: A Rare Complication Following Bentall Procedure
476
2012 ANZSCTS Annual Scientific Meeting
ABSTRACTS
percent, range 45–66 percent). The median peak gradient was 66 mmHg (range 64–70 mmHg), while the median mean gradient was 41 mmHg (range 40–41 mmHg). The median cardiopulmonary bypass time was 97 min (range 75–119 min) and median cross-clamp time was 57 min (range 57–66 min). There was no mortality, no incidence of ITA graft injury and no significant post-operative cardiac complications. All patients have been followed up with satisfactory outcomes. Discussion: In our experience, aortic valve replacement in the setting of a patent ITA graft can be performed safely on a beating heart with proximal aortic cross-clamping and mild-to-moderate hypothermia in appropriately selected patients. Utilisation of patent bypass grafts avoids cardioplegic arrest and the associated myocardial ischaemic-reperfusion injury, and potential for suboptimal myocardial protection due to regional warming and cardioplegia washout in the territory supplied by the ITA graft. This technique also avoids unnecessary dissection around heart with old patent grafts. http://dx.doi.org/10.1016/j.hlc.2013.03.046 2012 Poster Presentation/Panel 21 Development of a Risk Prediction Model for Large Volume Red Cell Transfusion in Cardiac Surgery Zoe McQuilten 1,3,4,6,∗ , Joanne Enticott 1 , Erica Wood 1,4 , Merrole Cole-Sinclair 6 , John McNeil 1 , Peter Cameron 1 , Christopher Reid 1 , Andrew Newcomb 7 , Julian Smith 2,5 , Louise Phillips 1 , Nick Andrianopoulos 1 1 Department of Epidemiology and Preventive Medicine, St Vincent’s Hospital, Melbourne, Australia 2 Department of Surgery, Monash University, St Vincent’s Hospital, Melbourne, Australia 3 Australian Red Cross Blood Service, St Vincent’s Hospital, Melbourne, Australia 4 Department of Haematology, St Vincent’s Hospital, Melbourne, Australia 5 Department of Cardiothoracic Surgery, Monash Medical Centre, St Vincent’s Hospital, Melbourne, Australia 6 Haematology Department, St Vincent’s Hospital, Melbourne, Australia 7 University of Melbourne, Department of Surgery, St Vincent’s Hospital, Melbourne, Australia
Introduction: Red blood cell (RBC) transfusion, especially large volume (five or more RBC), may be associated with worse outcomes in cardiac surgery. We developed predictive risk models to identify patients at risk of large volume RBC transfusion within 48 h of surgery to assist in clinical planning. Methods: Data on 14,980 cardiac procedures from 2005 to 2010 at six Victorian hospitals from the ANZSCTS Cardiac Surgery Database (CSD) were used for model creation. Additional data were extracted from laboratory information systems (LIS), including laboratory results and transfusion record. Clinically relevant variables considered were those associated with outcome on univariate analysis (p < 0.25). Bootstrap (1000 samples with replace-
Heart, Lung and Circulation 2013;22:455–489
ment on 95% of procedures) logistic regression was performed. Predictive models with variables identified as significant were validated using a bootstrap method. Results: Median age was 67 years (interquartile range 58–74) and 10,848 (72%) were male. There were 8784 (59%) isolated coronary artery bypass graft (CABG), 2267 (15%) isolated valve, 1647 (11%) CABG + valve, and 2282 (15%) other procedures. In total, 1733 (12%) received five or more RBC within 48 h. Procedure other than isolated CABG or valve, urgency more than elective, previous cardiac surgery and a pre-operative haemoglobin <130 g/L were associated with large volume transfusion in 100% of samples. Bootstrap validation showed this model had reasonable discriminative ability, with receiver operator curve area under the curve (AUC) 0.75 (95% CI 0.73–0.77), and acceptable calibration (Hosmer–Lemeshow (HL) pvalue 0.13 [95% CI 0.11–0.14]). When 12 variables identified as significant in 90% of samples were included in the model, the AUC increased to 0.78 (95% CI 0.76–0.79) with HL p-value 0.19 (95% CI 0.18–0.21). When all 37 variables were included, the AUC was 0.78 (0.78–0.79) and HL pvalue 0.17 (95% CI 0.15–0.18). Discussion: We have developed a simple prediction model for large volume RBC transfusion in cardiac surgery. Linkage of LIS data with the CSD allowed inclusion of an important predictor (pre-operative haemoglobin) and risk prediction for peri-operative transfusion. Future work will include development of a scoring system based on the model. The application of predictive risk models to monitor RBC transfusion as a quality indicator will also be explored. http://dx.doi.org/10.1016/j.hlc.2013.03.047 2012 Poster Presentation/Panel 22 Giant Coronary Aneurysms: A Rare Complication Following Bentall Procedure Felicity Meikle ∗ , Brecon Wademan, John Riordan Cardiothoracic Department, Wellington Hospital, Wellington, New Zealand Introduction: We present a case of a 44-year-old lady with Marfan syndrome who had an incidental finding of a large right coronary aneurysm 17 years following Bentall procedure for a Type A dissection. Case: Our patient is a 44-year-old Maori woman with Marfan syndrome who had undergone a Bentall procedure for Type A dissection in 1994. She recovered well until 2011 when she presented with sudden onset back pain. CT chest revealed a Sandford Type B dissection and a large aneurysm of the right coronary button. She came forward for a redo Bentall procedure in February 2012. At surgery she was found to have a 5 cm aneurysm, with a localised dissection, of the right coronary button and a smaller aneurysm of the left coronary button. Each coronary button orifice measured almost 2 cm in diameter. The previous Bentall graft was removed and replaced with a 23 mm ATS valved conduit. The coronary buttons were reduced down to a more appropriate size and reinforced
with Teflon buttresses. She recovered slowly and required insertion of a permanent pacemaker for complete heart block. She was transferred to a provincial hospital on postoperative day 14 for ongoing rehabilitation. Six months following her operation she continues to improve. Discussion: Coronary aneurysm formation is a rare complication following Bentall procedure but may be more common in Marfan patients [1]. A previous series reported a coronary aneurysm rate of nearly 50% in Marfan patients who had undergone Bentall procedure [2]. Most of these aneurysms are pseudoaneurysms. True coronary aneurysms are rare and appear to be related to amount of native aortic tissue included in the button [1]. It is likely that ongoing cystic medial degeneration of the native aortic tissue causes the button to become aneurysmal. It has been recommended that only a minimal amount of native aorta be included when fashioning coronary buttons [1]. Unfortunately, even with the best attempt at prevention these aneurysms may still occur and surgical correction can be challenging, as these patients often have dense mediastinal adhesions and fragile aneurysms. In this case we elected to revise the entire graft, thereby addressing both coronary buttons, and preventing progression of the left coronary aneurysm. Previous authors have described reconstruction with a modified Cabrol technique for single coronary aneurysm [1]. This case highlights the importance of lifelong radiological surveillance of all Marfan patients following Bentall procedure.
Reference [1] Okamoto K, Casselman FP, De Geest R, Vanermen H, et al. Giant left coronary ostial aneurysm after modified Bentall procedure in a Marfan patient. Interact Cardiovasc Thorac Surg 2008;7:1164–6. [2] Meijboom LJ, Nollen GJ, Merchant N, Webb GD, Groenink M, David TE, et al. Frequency of coronary ostial aneurysms after aortic root surgery in patients with the Marfan syndrome. Am J Cardiol 2002;89:1135–8.
http://dx.doi.org/10.1016/j.hlc.2013.03.048 2012 Poster Presentation/Panel 23 The Role of Closure Techniques in Sternal Dehiscence – An Artificial Model Felicity Meikle 1,∗ , Sean Galvin 1 , Yuanji Zhang 2 , Kim Pickering 2 , Adam El-Gamel 1 1 Cardiothoracic Department, Waikato Hospital, Hamilton, New Zealand 2 Department of Engineering, University of Waikato, Hamilton, New Zealand
Introduction: Sternal wound complications are a cause of significant post-operative morbidity and mortality and are generally more common in patients undergoing cardiac surgery who are elderly, have severe COPD, osteoporosis, diabetes or are undergoing bilateral mammary harvest [1]. Many surgeons have a preferred method of sternal closure and it has been suggested that how the sternum is closed may affect the risk of dehiscence [1,2].
2012 ANZSCTS Annual Scientific Meeting
477
This project was aimed at developing an artificial model of sternal dehiscence, given the difficulties of procuring cadaveric sternums and to see if there was a difference in dehiscence between the two wiring techniques favoured by surgeons in our unit–simple interrupted wires and the Gammex box closure. Methods: Ten low-density (10 pounds per cubic foot, pcf) and 10 high-density (20 pcf) polyurethane foam analogue sternums were split with a mounted band saw, mimicking a median sternotomy. The sternums were then re-approximated using No. 6 surgical steel wires, either with eight simple interrupted wires, or the Gammex closure technique, utilising four box wires. The sternums were mounted in a wood and silicone mold. A lateral distracting force was applied to separate the samples at 0.08 mm/s. Results: There were no significant differences between the interrupted wire and Gammex closures in lateral displacement at forces of up to 500 N. The maximum load reached was significantly greater in the Gammex closure – low density samples (776 N vs. 590 N, p 0.0127). The displacement per load of force applied was significantly lower in the Gammex – low density samples (0.007 vs. 0.010 mm/N, p 0.0081) and in the simple interrupted wire – high density samples (0.003 vs. 0.004 mm/N, p 0.0121). The greatest displacement occurred at the lower end of all of the sternums tested. Discussion: The polyurethane foam analogue sternums make a useful artificial model to test theories of sternal dehiscence [2]. Despite its small size this study has been able to produce similar results to previous studies utilising both cadaveric and artificial sternums [1,2]. The results of this project suggest that there may be a difference in sternal dehiscence related to both the method of wiring and density of the sternum. It would suggest that the Gammex closure might be most suitable for weaker sternums that have highest risk of dehiscence. Further testing is required with vertical, as well as lateral, distracting forces and with greater sample numbers.
References [1] Cheng W, Cameron DE, Warden KE, Fonger JD, Gott VL, et al. Biomechanical study of sternal closure techniques. Ann Thorac Surg 1993;55:737–40. [2] Uday K, Trumble DR, Magovern JA, et al. Lower sternal reinforcement improves the stability of sternal closure. Ann Thorac Surg 2003;75:1618–21.
http://dx.doi.org/10.1016/j.hlc.2013.03.049 2012 Poster Presentation/Panel 24 MRI Predictors of Short-Term Outcomes After High Risk Coronary Artery Bypass Surgery O. Mouline ∗ , M.J. Sheriff, M.K. Wilson, M.P. Vallely, R. Puranik Department of Cardiology and Cardiothoracic Surgery, Royal Prince Alfred Hospital, Sydney, Australia and the Baird Institute for Applied Heart and Lung Surgical Research, Sydney, Australia and The University of Sydney
ABSTRACTS
Heart, Lung and Circulation 2013;22:455–489
2012 ANZSCTS Annual Scientific Meeting
ABSTRACTS
percent, range 45–66 percent). The median peak gradient was 66 mmHg (range 64–70 mmHg), while the median mean gradient was 41 mmHg (range 40–41 mmHg). The median cardiopulmonary bypass time was 97 min (range 75–119 min) and median cross-clamp time was 57 min (range 57–66 min). There was no mortality, no incidence of ITA graft injury and no significant post-operative cardiac complications. All patients have been followed up with satisfactory outcomes. Discussion: In our experience, aortic valve replacement in the setting of a patent ITA graft can be performed safely on a beating heart with proximal aortic cross-clamping and mild-to-moderate hypothermia in appropriately selected patients. Utilisation of patent bypass grafts avoids cardioplegic arrest and the associated myocardial ischaemic-reperfusion injury, and potential for suboptimal myocardial protection due to regional warming and cardioplegia washout in the territory supplied by the ITA graft. This technique also avoids unnecessary dissection around heart with old patent grafts. http://dx.doi.org/10.1016/j.hlc.2013.03.046 2012 Poster Presentation/Panel 21 Development of a Risk Prediction Model for Large Volume Red Cell Transfusion in Cardiac Surgery Zoe McQuilten 1,3,4,6,∗ , Joanne Enticott 1 , Erica Wood 1,4 , Merrole Cole-Sinclair 6 , John McNeil 1 , Peter Cameron 1 , Christopher Reid 1 , Andrew Newcomb 7 , Julian Smith 2,5 , Louise Phillips 1 , Nick Andrianopoulos 1 1 Department of Epidemiology and Preventive Medicine, St Vincent’s Hospital, Melbourne, Australia 2 Department of Surgery, Monash University, St Vincent’s Hospital, Melbourne, Australia 3 Australian Red Cross Blood Service, St Vincent’s Hospital, Melbourne, Australia 4 Department of Haematology, St Vincent’s Hospital, Melbourne, Australia 5 Department of Cardiothoracic Surgery, Monash Medical Centre, St Vincent’s Hospital, Melbourne, Australia 6 Haematology Department, St Vincent’s Hospital, Melbourne, Australia 7 University of Melbourne, Department of Surgery, St Vincent’s Hospital, Melbourne, Australia
Introduction: Red blood cell (RBC) transfusion, especially large volume (five or more RBC), may be associated with worse outcomes in cardiac surgery. We developed predictive risk models to identify patients at risk of large volume RBC transfusion within 48 h of surgery to assist in clinical planning. Methods: Data on 14,980 cardiac procedures from 2005 to 2010 at six Victorian hospitals from the ANZSCTS Cardiac Surgery Database (CSD) were used for model creation. Additional data were extracted from laboratory information systems (LIS), including laboratory results and transfusion record. Clinically relevant variables considered were those associated with outcome on univariate analysis (p < 0.25). Bootstrap (1000 samples with replace-
Heart, Lung and Circulation 2013;22:455–489
ment on 95% of procedures) logistic regression was performed. Predictive models with variables identified as significant were validated using a bootstrap method. Results: Median age was 67 years (interquartile range 58–74) and 10,848 (72%) were male. There were 8784 (59%) isolated coronary artery bypass graft (CABG), 2267 (15%) isolated valve, 1647 (11%) CABG + valve, and 2282 (15%) other procedures. In total, 1733 (12%) received five or more RBC within 48 h. Procedure other than isolated CABG or valve, urgency more than elective, previous cardiac surgery and a pre-operative haemoglobin <130 g/L were associated with large volume transfusion in 100% of samples. Bootstrap validation showed this model had reasonable discriminative ability, with receiver operator curve area under the curve (AUC) 0.75 (95% CI 0.73–0.77), and acceptable calibration (Hosmer–Lemeshow (HL) pvalue 0.13 [95% CI 0.11–0.14]). When 12 variables identified as significant in 90% of samples were included in the model, the AUC increased to 0.78 (95% CI 0.76–0.79) with HL p-value 0.19 (95% CI 0.18–0.21). When all 37 variables were included, the AUC was 0.78 (0.78–0.79) and HL pvalue 0.17 (95% CI 0.15–0.18). Discussion: We have developed a simple prediction model for large volume RBC transfusion in cardiac surgery. Linkage of LIS data with the CSD allowed inclusion of an important predictor (pre-operative haemoglobin) and risk prediction for peri-operative transfusion. Future work will include development of a scoring system based on the model. The application of predictive risk models to monitor RBC transfusion as a quality indicator will also be explored. http://dx.doi.org/10.1016/j.hlc.2013.03.047 2012 Poster Presentation/Panel 22 Giant Coronary Aneurysms: A Rare Complication Following Bentall Procedure Felicity Meikle ∗ , Brecon Wademan, John Riordan Cardiothoracic Department, Wellington Hospital, Wellington, New Zealand Introduction: We present a case of a 44-year-old lady with Marfan syndrome who had an incidental finding of a large right coronary aneurysm 17 years following Bentall procedure for a Type A dissection. Case: Our patient is a 44-year-old Maori woman with Marfan syndrome who had undergone a Bentall procedure for Type A dissection in 1994. She recovered well until 2011 when she presented with sudden onset back pain. CT chest revealed a Sandford Type B dissection and a large aneurysm of the right coronary button. She came forward for a redo Bentall procedure in February 2012. At surgery she was found to have a 5 cm aneurysm, with a localised dissection, of the right coronary button and a smaller aneurysm of the left coronary button. Each coronary button orifice measured almost 2 cm in diameter. The previous Bentall graft was removed and replaced with a 23 mm ATS valved conduit. The coronary buttons were reduced down to a more appropriate size and reinforced
with Teflon buttresses. She recovered slowly and required insertion of a permanent pacemaker for complete heart block. She was transferred to a provincial hospital on postoperative day 14 for ongoing rehabilitation. Six months following her operation she continues to improve. Discussion: Coronary aneurysm formation is a rare complication following Bentall procedure but may be more common in Marfan patients [1]. A previous series reported a coronary aneurysm rate of nearly 50% in Marfan patients who had undergone Bentall procedure [2]. Most of these aneurysms are pseudoaneurysms. True coronary aneurysms are rare and appear to be related to amount of native aortic tissue included in the button [1]. It is likely that ongoing cystic medial degeneration of the native aortic tissue causes the button to become aneurysmal. It has been recommended that only a minimal amount of native aorta be included when fashioning coronary buttons [1]. Unfortunately, even with the best attempt at prevention these aneurysms may still occur and surgical correction can be challenging, as these patients often have dense mediastinal adhesions and fragile aneurysms. In this case we elected to revise the entire graft, thereby addressing both coronary buttons, and preventing progression of the left coronary aneurysm. Previous authors have described reconstruction with a modified Cabrol technique for single coronary aneurysm [1]. This case highlights the importance of lifelong radiological surveillance of all Marfan patients following Bentall procedure.
Reference [1] Okamoto K, Casselman FP, De Geest R, Vanermen H, et al. Giant left coronary ostial aneurysm after modified Bentall procedure in a Marfan patient. Interact Cardiovasc Thorac Surg 2008;7:1164–6. [2] Meijboom LJ, Nollen GJ, Merchant N, Webb GD, Groenink M, David TE, et al. Frequency of coronary ostial aneurysms after aortic root surgery in patients with the Marfan syndrome. Am J Cardiol 2002;89:1135–8.
http://dx.doi.org/10.1016/j.hlc.2013.03.048 2012 Poster Presentation/Panel 23 The Role of Closure Techniques in Sternal Dehiscence – An Artificial Model Felicity Meikle 1,∗ , Sean Galvin 1 , Yuanji Zhang 2 , Kim Pickering 2 , Adam El-Gamel 1 1 Cardiothoracic Department, Waikato Hospital, Hamilton, New Zealand 2 Department of Engineering, University of Waikato, Hamilton, New Zealand
Introduction: Sternal wound complications are a cause of significant post-operative morbidity and mortality and are generally more common in patients undergoing cardiac surgery who are elderly, have severe COPD, osteoporosis, diabetes or are undergoing bilateral mammary harvest [1]. Many surgeons have a preferred method of sternal closure and it has been suggested that how the sternum is closed may affect the risk of dehiscence [1,2].
2012 ANZSCTS Annual Scientific Meeting
477
This project was aimed at developing an artificial model of sternal dehiscence, given the difficulties of procuring cadaveric sternums and to see if there was a difference in dehiscence between the two wiring techniques favoured by surgeons in our unit–simple interrupted wires and the Gammex box closure. Methods: Ten low-density (10 pounds per cubic foot, pcf) and 10 high-density (20 pcf) polyurethane foam analogue sternums were split with a mounted band saw, mimicking a median sternotomy. The sternums were then re-approximated using No. 6 surgical steel wires, either with eight simple interrupted wires, or the Gammex closure technique, utilising four box wires. The sternums were mounted in a wood and silicone mold. A lateral distracting force was applied to separate the samples at 0.08 mm/s. Results: There were no significant differences between the interrupted wire and Gammex closures in lateral displacement at forces of up to 500 N. The maximum load reached was significantly greater in the Gammex closure – low density samples (776 N vs. 590 N, p 0.0127). The displacement per load of force applied was significantly lower in the Gammex – low density samples (0.007 vs. 0.010 mm/N, p 0.0081) and in the simple interrupted wire – high density samples (0.003 vs. 0.004 mm/N, p 0.0121). The greatest displacement occurred at the lower end of all of the sternums tested. Discussion: The polyurethane foam analogue sternums make a useful artificial model to test theories of sternal dehiscence [2]. Despite its small size this study has been able to produce similar results to previous studies utilising both cadaveric and artificial sternums [1,2]. The results of this project suggest that there may be a difference in sternal dehiscence related to both the method of wiring and density of the sternum. It would suggest that the Gammex closure might be most suitable for weaker sternums that have highest risk of dehiscence. Further testing is required with vertical, as well as lateral, distracting forces and with greater sample numbers.
References [1] Cheng W, Cameron DE, Warden KE, Fonger JD, Gott VL, et al. Biomechanical study of sternal closure techniques. Ann Thorac Surg 1993;55:737–40. [2] Uday K, Trumble DR, Magovern JA, et al. Lower sternal reinforcement improves the stability of sternal closure. Ann Thorac Surg 2003;75:1618–21.
http://dx.doi.org/10.1016/j.hlc.2013.03.049 2012 Poster Presentation/Panel 24 MRI Predictors of Short-Term Outcomes After High Risk Coronary Artery Bypass Surgery O. Mouline ∗ , M.J. Sheriff, M.K. Wilson, M.P. Vallely, R. Puranik Department of Cardiology and Cardiothoracic Surgery, Royal Prince Alfred Hospital, Sydney, Australia and the Baird Institute for Applied Heart and Lung Surgical Research, Sydney, Australia and The University of Sydney
ABSTRACTS
Heart, Lung and Circulation 2013;22:455–489