- Email: [email protected]
Right Ventricular Outflow Tract Reconstruction: The Impact of Allograft Characteristics
Ann Thorac Surg 2011;91:2020 –7
with exclusion of other confounders, the number of grafts per patient was not a significant predictor of early mortality. Sander Bramer, MD Albert H. M. van Straten, MD, PhD Mohamed A. Soliman Hamad, MD, PhD Eric Berreklouw, MD, PhD Department of Cardiothoracic Surgery Catharina Hospital, Eindhoven, The Netherlands e-mail: [email protected] Elisabeth J. Martens, PhD Department of Education and Research, Catharina Hospital Eindhoven, The Netherlands; Department of Medical Psychology, Center of Research on Psychology in Somatic Diseases Tilburg University Tilburg, The Netherlands Jos G. Maessen, MD, PhD Department of Cardiothoracic Surgery Cardiovascular Research Institute Maastricht – CARIM Maastricht University Medical Center – MUMC Maastricht, The Netherlands
References 1. Polat A, Mert B, Polat EB, Yucel C, Erentug V. Impact of postoperative atrial fibrillation after CABG (letter). Ann Thorac Surg 2011;91:2024. 2. Bramer S, van Straten AH, Soliman Hamad MA, Berreklouw E, Martens EJ, Maessen JG. The impact of new-onset postoperative atrial fibrillatian on mortality after coronary artery bypass grafting. Ann Thorac Surg 2010;90:443–50. 3. Güler M, Eren E, Toker ME, et al. Metoprolol for prevention of atrial fibrillation after coronary bypass. Turk Kardiyol Dern Ars 2001;29:619 –25. 4. Crystal E, Garfinkle MS, Connoly S, Ginger T, Ysusf S. Interventions for preventing post-operative atrial fibrillation in patients undergoing heart surgery. Cochrane Database Syst Rev 2004;4:CD003611. 5. Elenbaas TW, Soliman Hamad MA, Schonberger JP, Martens EJ, van Zundert AJ, van Straten AH. Preoperative atrial fibrillation and elevated C-reactive protein levels as predictors of mediastinitis after coronary artery bypass grafting. Ann Thorac Surg 2010;89:704 –9.
CORRESPONDENCE
2025
calculate and compare rate estimates, in this case hazard ratios. Furthermore, the total follow-up period differed significantly between the Contegra group and the allograft group. Therefore, not the log-rank test but the Tarone-Ware test would be a more appropriate statistical test to compare these groups. We have investigated the issue of blood group compatibility in our own patient population, as well as the influence of allograft quality code assignment. All patients who receive an allograft for RVOT reconstruction at our institution are systematically registered. Between August 1986 and March 2009, 509 allografts were implanted in 463 pediatric and adult patients. The mean age of donors was 37 ⫾ 18 years (range, 0 to 65 years). The mean age of patients was 19 ⫾ 15 years (range, 0.02 to 66 years). The mean follow-up time was 9 years. Seventy-six allograft reinterventions were required in 69 patients (including 13 percutaneous stented valve implantations). Allograft dysfunction was related to structural valve failure in 69 patients, nonstructural failure in 3 patients, and endocarditis in 4 patients. Freedom from allograft reintervention was 88% (95% CI, 84% to 91%) at 10 years and 78% (95% CI, 72% to 83%) at 15 years. Overall, the reoperation rate was not significantly higher in the group of non–ABO compatible allografts as compared with ABO-compatible allografts (HR 0.63; 95% CI, 0.36 to 1.10). Christenson and colleagues have observed a strong correlation between non–ABO compatible allografts and increased reoperation rate in patients younger than 3 years. In our patient population, also in this group (N ⫽ 102 of which 31 patients required an allograft re-intervention) the re-intervention rate was not significantly higher in the group of non-ABO compatible allografts as compared to ABO compatible allografts (HR 0.76, 95% CI 0.33-1.73). Furthermore, our results indicate that assignment of allograft quality codes is not associated with the durability of allografts used for RVOT reconstruction. Allografts with the highest quality code 1 (N ⫽ 184) showed a performance comparable to allografts with quality code 2 (N ⫽ 164) (HR 0.61; 95% CI, 0.34 to 1.10) and to allografts with quality code ⱖ3 (N ⫽ 112) (HR 1.03; 95% CI, 0.50 to 2.12). From 49 allografts (9.6 %) the quality code could not be retrieved. In conclusion, in our experience blood group compatibility and assignment of quality codes do not have an impact on allograft durability.
M. Mostafa Mokhles is funded by a Mosaic grant of the Netherlands Organisation for Scientific Research (NWO 017.006.058).
We read with great interest the recent article by Christenson and colleagues [1] addressing the impact of ABO blood group compatibility on the reoperation rate of allograft conduits used for right ventricular outflow tract (RVOT) reconstruction. They show that blood group–noncompatible allografts have a significantly higher early reoperation rate compared with blood group– compatible allografts. In Table 4, Christenson and colleagues report the impact of age and different conduits used on the reoperation rate during follow-up by calculating and comparing risk estimates. However, by doing this the authors do not take into account the time dependency of the event (reoperation). If one is interested in investigating the impact of certain variables on a timedependent event, a more appropriate approach would be to © 2011 by The Society of Thoracic Surgeons Published by Elsevier Inc
M. Mostafa Mokhles, MS Antoon J. van den Bogaerdt, PhD Johanna J.M. Takkenberg, MD, PhD Ad J.J.C. Bogers, MD, PhD Department of Cardiothoracic Surgery Erasmus University Medical Center, Room Bd 575 PO Box 2040 3000 CA Rotterdam The Netherlands e-mail: [email protected]
Reference 1. Christenson JT, Sierra J, Colina Manzano NE, et al. Homografts and xenografts for right ventricular outflow tract reconstruction: Long-term results. Ann Thorac Surg 2010;90: 1287–93. 0003-4975/$36.00
MISCELLANEOUS
Right Ventricular Outflow Tract Reconstruction: The Impact of Allograft Characteristics To the Editor:
with exclusion of other confounders, the number of grafts per patient was not a significant predictor of early mortality. Sander Bramer, MD Albert H. M. van Straten, MD, PhD Mohamed A. Soliman Hamad, MD, PhD Eric Berreklouw, MD, PhD Department of Cardiothoracic Surgery Catharina Hospital, Eindhoven, The Netherlands e-mail: [email protected] Elisabeth J. Martens, PhD Department of Education and Research, Catharina Hospital Eindhoven, The Netherlands; Department of Medical Psychology, Center of Research on Psychology in Somatic Diseases Tilburg University Tilburg, The Netherlands Jos G. Maessen, MD, PhD Department of Cardiothoracic Surgery Cardiovascular Research Institute Maastricht – CARIM Maastricht University Medical Center – MUMC Maastricht, The Netherlands
References 1. Polat A, Mert B, Polat EB, Yucel C, Erentug V. Impact of postoperative atrial fibrillation after CABG (letter). Ann Thorac Surg 2011;91:2024. 2. Bramer S, van Straten AH, Soliman Hamad MA, Berreklouw E, Martens EJ, Maessen JG. The impact of new-onset postoperative atrial fibrillatian on mortality after coronary artery bypass grafting. Ann Thorac Surg 2010;90:443–50. 3. Güler M, Eren E, Toker ME, et al. Metoprolol for prevention of atrial fibrillation after coronary bypass. Turk Kardiyol Dern Ars 2001;29:619 –25. 4. Crystal E, Garfinkle MS, Connoly S, Ginger T, Ysusf S. Interventions for preventing post-operative atrial fibrillation in patients undergoing heart surgery. Cochrane Database Syst Rev 2004;4:CD003611. 5. Elenbaas TW, Soliman Hamad MA, Schonberger JP, Martens EJ, van Zundert AJ, van Straten AH. Preoperative atrial fibrillation and elevated C-reactive protein levels as predictors of mediastinitis after coronary artery bypass grafting. Ann Thorac Surg 2010;89:704 –9.
CORRESPONDENCE
2025
calculate and compare rate estimates, in this case hazard ratios. Furthermore, the total follow-up period differed significantly between the Contegra group and the allograft group. Therefore, not the log-rank test but the Tarone-Ware test would be a more appropriate statistical test to compare these groups. We have investigated the issue of blood group compatibility in our own patient population, as well as the influence of allograft quality code assignment. All patients who receive an allograft for RVOT reconstruction at our institution are systematically registered. Between August 1986 and March 2009, 509 allografts were implanted in 463 pediatric and adult patients. The mean age of donors was 37 ⫾ 18 years (range, 0 to 65 years). The mean age of patients was 19 ⫾ 15 years (range, 0.02 to 66 years). The mean follow-up time was 9 years. Seventy-six allograft reinterventions were required in 69 patients (including 13 percutaneous stented valve implantations). Allograft dysfunction was related to structural valve failure in 69 patients, nonstructural failure in 3 patients, and endocarditis in 4 patients. Freedom from allograft reintervention was 88% (95% CI, 84% to 91%) at 10 years and 78% (95% CI, 72% to 83%) at 15 years. Overall, the reoperation rate was not significantly higher in the group of non–ABO compatible allografts as compared with ABO-compatible allografts (HR 0.63; 95% CI, 0.36 to 1.10). Christenson and colleagues have observed a strong correlation between non–ABO compatible allografts and increased reoperation rate in patients younger than 3 years. In our patient population, also in this group (N ⫽ 102 of which 31 patients required an allograft re-intervention) the re-intervention rate was not significantly higher in the group of non-ABO compatible allografts as compared to ABO compatible allografts (HR 0.76, 95% CI 0.33-1.73). Furthermore, our results indicate that assignment of allograft quality codes is not associated with the durability of allografts used for RVOT reconstruction. Allografts with the highest quality code 1 (N ⫽ 184) showed a performance comparable to allografts with quality code 2 (N ⫽ 164) (HR 0.61; 95% CI, 0.34 to 1.10) and to allografts with quality code ⱖ3 (N ⫽ 112) (HR 1.03; 95% CI, 0.50 to 2.12). From 49 allografts (9.6 %) the quality code could not be retrieved. In conclusion, in our experience blood group compatibility and assignment of quality codes do not have an impact on allograft durability.
M. Mostafa Mokhles is funded by a Mosaic grant of the Netherlands Organisation for Scientific Research (NWO 017.006.058).
We read with great interest the recent article by Christenson and colleagues [1] addressing the impact of ABO blood group compatibility on the reoperation rate of allograft conduits used for right ventricular outflow tract (RVOT) reconstruction. They show that blood group–noncompatible allografts have a significantly higher early reoperation rate compared with blood group– compatible allografts. In Table 4, Christenson and colleagues report the impact of age and different conduits used on the reoperation rate during follow-up by calculating and comparing risk estimates. However, by doing this the authors do not take into account the time dependency of the event (reoperation). If one is interested in investigating the impact of certain variables on a timedependent event, a more appropriate approach would be to © 2011 by The Society of Thoracic Surgeons Published by Elsevier Inc
M. Mostafa Mokhles, MS Antoon J. van den Bogaerdt, PhD Johanna J.M. Takkenberg, MD, PhD Ad J.J.C. Bogers, MD, PhD Department of Cardiothoracic Surgery Erasmus University Medical Center, Room Bd 575 PO Box 2040 3000 CA Rotterdam The Netherlands e-mail: [email protected]
Reference 1. Christenson JT, Sierra J, Colina Manzano NE, et al. Homografts and xenografts for right ventricular outflow tract reconstruction: Long-term results. Ann Thorac Surg 2010;90: 1287–93. 0003-4975/$36.00
MISCELLANEOUS
Right Ventricular Outflow Tract Reconstruction: The Impact of Allograft Characteristics To the Editor: