- Email: [email protected]
Vein Graft Patency After Coronary Artery Bypass Grafting: Too Complex to Simplify
1142
CORRESPONDENCE
2. Gopaldas RR, Chu D, Cornwell LD, et al. Cirrhosis as a moderator of outcomes in coronary artery bypass grafting and off-pump coronary artery bypass operations: a 12-year population-based study. Ann Thorac Surg 2013;96:1310–5. 3. Nguyen LL, Barshes NR. Analysis of large databases in vascular surgery. J Vasc Surg 2010;52:768–74.
Vein Graft Patency After Coronary Artery Bypass Grafting: Too Complex to Simplify To the Editor: We read with interest the meta-analysis presented by Zhang and colleagues [1] comparing graft patency after off-pump and onpump coronary artery bypass grafting. Although we applaud their effort, we believe that certain points merit further discussion. They report that saphenous vein graft patency is significantly lower after off-pump operations, whereas arterial conduit patency is similar. But they have combined data with follow-up periods ranging from 3 weeks [2] to 7.5 years [3]. The authors themselves state that the mechanism of vein graft occlusion is distinctly different at these two time periods [1]. Our revised statistical analysis, after excluding the two studies [3, 4] with long follow-up, still demonstrates similar outcome (risk ratio for saphenous vein graft graft occlusion, 1.41; 95% confidence interval, 1.24 to 1.60; p < 0.01). Lower levels of anticoagulation, reduced fibrinolysis, and less platelet destruction all create a thrombogenic environment after off-pump operations [5]. We recently demonstrated that dual antiplatelet therapy not only improves saphenous vein graft patency but also reduces cardiac events [6]. Thus, although multiple complex factors affect early vein graft patency, if permissible, dual antiplatelet therapy is clearly beneficial after off-pump operations. Salil V. Deo, MS, MCh
MISCELLANEOUS
Adventist Wockhardt Heart Hospital Athwalines, Surat Gujarat 395001 India e-mail: [email protected]
Dr Deo discloses a financial relationship with Astra Zeneca. References 1. Zhang B, Zhou J, Li H, Liu Z, Chen A, Zhao Q. Comparison of graft patency between off-pump and on-pump coronary artery bypass grafting: an updated meta-analysis. Ann Thorac Surg 2014. 2. Kobayashi J, Tashiro T, Ochi M, et al. Early outcome of a randomized comparison of off-pump and on-pump multiple arterial coronary revascularization. Circulation 2005;112 (9 Suppl):I338–43. 3. Puskas JD, Williams WH, O’Donnell R, et al. Off-pump and on-pump coronary artery bypass grafting are associated with similar graft patency, myocardial ischemia, and freedom from reintervention: Long-term follow-up of a randomized trial. Ann Thorac Surg 2011;91:1836–42; discussion 1842–3. 4. Angelini GD, Culliford L, Smith DK, et al. Effects of on- and off-pump coronary artery surgery on graft patency, survival, and health-related quality of life: long-term follow-up of 2 randomized controlled trials. J Thorac Cardiovasc Surg 2009;137:295–303.
Ó 2014 by The Society of Thoracic Surgeons Published by Elsevier Inc
Ann Thorac Surg 2014;98:1141–4
5. Vallely MP, Bannon PG, Bayfield MS, Hughes CF, Kritharides L. Quantitative and temporal differences in coagulation, fibrinolysis and platelet activation after on-pump and off-pump coronary artery bypass surgery. Heart Lung Circ 2009;18:123–30. 6. Deo SV, Dunlay SM, Shah IK, et al. Dual anti-platelet therapy after coronary artery bypass grafting: is there any benefit? A systematic review and meta-analysis. J Card Surg 2013;28: 109–16.
Is Preoperative Fibrinogen Really Not Associated With Blood Transfusion? To the Editor: In a recent article, Walden and colleagues [1] presented interesting results related to the association between preoperative fibrinogen and the risk of excessive bleeding. They found a positive association between preoperative fibrinogen and excessive bleeding after operations; however, no association was found between preoperative fibrinogen and blood transfusion. We doubt those conclusions because of the following three reasons: 1. About the definition of transfusion, did authors mean just red blood cell (RBC) transfusion or all three blood products (RBC/plasma/platelets)? If blood transfusion only meant RBCs, then there was no need to record transfusion of all three blood products (RBC/plasma/platelet) in the Methods section. Or, if they did mean the three blood products, then the association between preoperative fibrinogen and blood transfusion should have been analyzed separately. 2. Just like analyzing preoperative fibrinogen and postoperative excessive bleeding (grouped as >1,000 mL/12 h or <1,000 mL/12 h), the analysis of preoperative fibrinogen and blood transfusion should also be based on different groups of transfusion according to different transfusion volume, such as 1 to 2 units, 2 to 4 units, 4 to 6 units, or more. 3. The authors analyzed preoperative fibrinogen and postoperative excessive bleeding during 12 hours after the operation, but when they analyzed the association between preoperative fibrinogen and blood transfusion, the period of transfusion was the whole hospital stay instead of just after the operation. So we guess that if the period of transfusion were defined as the postoperative period, especially 12 hours or 1 day after the operation, the conclusions might be totally different. Finally, the association between preoperative fibrinogen and blood transfusion may not be negative, and the authors should be more careful when making conclusions. Bei Li, MB* Bin Tan, MB* Chunxia Chen, MB Li Zhao, MB Li Qin, MB Blood Transfusion Service Department of Laboratory Medicine West China Hospital, Sichuan University Chengdu 610041, People’s Republic of China e-mail: [email protected] *Bei Li and Bin Tan are equal contributors.
0003-4975/$36.00
CORRESPONDENCE
2. Gopaldas RR, Chu D, Cornwell LD, et al. Cirrhosis as a moderator of outcomes in coronary artery bypass grafting and off-pump coronary artery bypass operations: a 12-year population-based study. Ann Thorac Surg 2013;96:1310–5. 3. Nguyen LL, Barshes NR. Analysis of large databases in vascular surgery. J Vasc Surg 2010;52:768–74.
Vein Graft Patency After Coronary Artery Bypass Grafting: Too Complex to Simplify To the Editor: We read with interest the meta-analysis presented by Zhang and colleagues [1] comparing graft patency after off-pump and onpump coronary artery bypass grafting. Although we applaud their effort, we believe that certain points merit further discussion. They report that saphenous vein graft patency is significantly lower after off-pump operations, whereas arterial conduit patency is similar. But they have combined data with follow-up periods ranging from 3 weeks [2] to 7.5 years [3]. The authors themselves state that the mechanism of vein graft occlusion is distinctly different at these two time periods [1]. Our revised statistical analysis, after excluding the two studies [3, 4] with long follow-up, still demonstrates similar outcome (risk ratio for saphenous vein graft graft occlusion, 1.41; 95% confidence interval, 1.24 to 1.60; p < 0.01). Lower levels of anticoagulation, reduced fibrinolysis, and less platelet destruction all create a thrombogenic environment after off-pump operations [5]. We recently demonstrated that dual antiplatelet therapy not only improves saphenous vein graft patency but also reduces cardiac events [6]. Thus, although multiple complex factors affect early vein graft patency, if permissible, dual antiplatelet therapy is clearly beneficial after off-pump operations. Salil V. Deo, MS, MCh
MISCELLANEOUS
Adventist Wockhardt Heart Hospital Athwalines, Surat Gujarat 395001 India e-mail: [email protected]
Dr Deo discloses a financial relationship with Astra Zeneca. References 1. Zhang B, Zhou J, Li H, Liu Z, Chen A, Zhao Q. Comparison of graft patency between off-pump and on-pump coronary artery bypass grafting: an updated meta-analysis. Ann Thorac Surg 2014. 2. Kobayashi J, Tashiro T, Ochi M, et al. Early outcome of a randomized comparison of off-pump and on-pump multiple arterial coronary revascularization. Circulation 2005;112 (9 Suppl):I338–43. 3. Puskas JD, Williams WH, O’Donnell R, et al. Off-pump and on-pump coronary artery bypass grafting are associated with similar graft patency, myocardial ischemia, and freedom from reintervention: Long-term follow-up of a randomized trial. Ann Thorac Surg 2011;91:1836–42; discussion 1842–3. 4. Angelini GD, Culliford L, Smith DK, et al. Effects of on- and off-pump coronary artery surgery on graft patency, survival, and health-related quality of life: long-term follow-up of 2 randomized controlled trials. J Thorac Cardiovasc Surg 2009;137:295–303.
Ó 2014 by The Society of Thoracic Surgeons Published by Elsevier Inc
Ann Thorac Surg 2014;98:1141–4
5. Vallely MP, Bannon PG, Bayfield MS, Hughes CF, Kritharides L. Quantitative and temporal differences in coagulation, fibrinolysis and platelet activation after on-pump and off-pump coronary artery bypass surgery. Heart Lung Circ 2009;18:123–30. 6. Deo SV, Dunlay SM, Shah IK, et al. Dual anti-platelet therapy after coronary artery bypass grafting: is there any benefit? A systematic review and meta-analysis. J Card Surg 2013;28: 109–16.
Is Preoperative Fibrinogen Really Not Associated With Blood Transfusion? To the Editor: In a recent article, Walden and colleagues [1] presented interesting results related to the association between preoperative fibrinogen and the risk of excessive bleeding. They found a positive association between preoperative fibrinogen and excessive bleeding after operations; however, no association was found between preoperative fibrinogen and blood transfusion. We doubt those conclusions because of the following three reasons: 1. About the definition of transfusion, did authors mean just red blood cell (RBC) transfusion or all three blood products (RBC/plasma/platelets)? If blood transfusion only meant RBCs, then there was no need to record transfusion of all three blood products (RBC/plasma/platelet) in the Methods section. Or, if they did mean the three blood products, then the association between preoperative fibrinogen and blood transfusion should have been analyzed separately. 2. Just like analyzing preoperative fibrinogen and postoperative excessive bleeding (grouped as >1,000 mL/12 h or <1,000 mL/12 h), the analysis of preoperative fibrinogen and blood transfusion should also be based on different groups of transfusion according to different transfusion volume, such as 1 to 2 units, 2 to 4 units, 4 to 6 units, or more. 3. The authors analyzed preoperative fibrinogen and postoperative excessive bleeding during 12 hours after the operation, but when they analyzed the association between preoperative fibrinogen and blood transfusion, the period of transfusion was the whole hospital stay instead of just after the operation. So we guess that if the period of transfusion were defined as the postoperative period, especially 12 hours or 1 day after the operation, the conclusions might be totally different. Finally, the association between preoperative fibrinogen and blood transfusion may not be negative, and the authors should be more careful when making conclusions. Bei Li, MB* Bin Tan, MB* Chunxia Chen, MB Li Zhao, MB Li Qin, MB Blood Transfusion Service Department of Laboratory Medicine West China Hospital, Sichuan University Chengdu 610041, People’s Republic of China e-mail: [email protected] *Bei Li and Bin Tan are equal contributors.
0003-4975/$36.00