pii: jc- 00421-16http://dx.doi.org/10.5664/jcsm.6298
LE TTER S TO T H E EDITOR
Obstructive Sleep Apnea: A Risk Factor of Cardiac Valve Replacement Surgery Response to Esquinas and De Santo. Impact of sleep-disordered breathing on postoperative outcomes: another brick in the wall. J Clin Sleep Med 2016;12(11):1571. Ning Ding1; Bu-Qing Ni2; Hong Wang1; Shi-Jiang Zhang, PhD, MD2; Xi-Long Zhang, PhD, MD1 Department of Respiratory and Critical Care Medicine, the First Affiliated Hospital of Nanjing Medical University, Nanjing, China; 2Department of Cardiovascular Surgery, the First Affiliated Hospital of Nanjing Medical University, Nanjing, China
1
We thank Dr. Antonio Maria Esquinas and Luca Salvatore De Santo1 for their interest and commentary regarding our manuscript detailing obstructive sleep apnea (OSA) increases the perioperative risk of cardiac valve replacement surgery. We also are thankful for the opportunity to clarify some limitations in our study. This article2 is one of our series of studies on “sleep apnea and valvular heart disease.” In our previous publication,3 we gave a detailed description about the difference among patients with various kinds of valvular lesions. Since in this study we focused on the correlation between sleep apnea and postoperative complications, special attention was not paid to the difference in types of cardiac valvular surgery. Here, we listed the types of cardiac valvular surgery in Table 1 and compared the clinical parameters between single valve replacement and multiple valve replacement patients in Table 2. In addition, the correlations were analyzed about types of cardiac valve replacement and postoperative adverse events, in which we found that when comparing with single valve replacement, multiple valve replacement did not increase ICU length of stay and duration of mechanical ventilation. In some previous studies,4,5 the preoperative baseline diseases of their study patients such as hypertension, diabetes mellitus, stroke, coronary artery disease (CAD) and chronic obstructive pulmonary disease (COPD) were described. In our study population, there are 10 (3.4%) patients combined with hypertension, 5 (1.7%) combined with diabetes, 5 (1.7%) combined with stroke, 15 (5.2%) combined with left atrial thrombi, 24 (8.3%) combined with CAD, and 2 (0.7%) combined with COPD. Excuse us for our carelessness, when we designed the study, we failed to take intraoperative blood management into consideration. Therefore, the data about blooding volume/ transfusion blood volume were devoid in this study. This is a limitation of our study. Our selection of postoperative adverse outcomes was based on some studies.6,7 We set up six adverse outcomes at beginning of the study: ICU length of stay ≥ 25 h, mechanical ventilation ≥ 20 h, pacemaker use, cardiopulmonary bypass ≥ 110 min, first dose of dopamine in ICU ≥ 3 μg/kg·min and first dose of dobutamine in ICU ≥ 3 μg/kg·min. However, because of the suggestions from reviewers and editors as well as the following reasons: 1) cardiopulmonary bypass ≥ 110 1573
min was more associated with the complex of cardiac surgery itself rather than perioperative risks; 2) both first dose of dopamine in ICU ≥ 3 µg/kg·min and first dose of dobutamine in ICU ≥ 3 µg/kg·min were more closely related to preoperative cardiac function and bleeding amount during surgery rather than perioperative risks, the adverse events of cardiopulmonary bypass ≥ 110 min, first dose of dopamine in ICU ≥ 3 μg/ kg·min and first dose of dobutamine in ICU ≥ 3 μg/kg·min were deleted. Finally, only the following three outcomes were kept: ICU length of stay ≥ 25 h (reflect overall worsening of postoperative recovery), mechanical ventilation ≥ 20 h (reflect postoperative respiratory insufficiency) and pacemaker use (reflect severe cardiac arrhythmia). Other postoperative adverse events such as reintubation, infection, pneumonia, myocardial infarction,4,6,8-10 were not included in our original protocol and failed to be recorded in our study as well. This limitation will push us to pursue more proper observation in our further study in the future. In spite of this, we have, to say the least, detected the phenomenon that preoperative OSA could increase the perioperative risk of cardiac valve replacement surgery. This finding might remind surgeons to consider sleep apnea in preoperative evaluation and postoperative management. Apart from the limitations mentioned above, there are another two important limitations mentioned in this article, lack
Table 1—Types of heart valve replacement. MVR TVR AVR MVR+TVR MVR+AVR TVR+AVR MVR+TVR+AVR Total
Case 90 5 38 73 34 3 47 290
% 31.0 1.7 13.1 25.2 11.7 1.0 16.2 100.0
MVR, mitral valve replacement; TVR, tricuspid valve replacement; AVR, aortic valve replacement
Journal of Clinical Sleep Medicine, Vol. 12, No. 11, 2016
N Ding, BQ Ni, H Wang et al. Letter to the Editor
Table 2—Comparisons of clinical parameters between single valve replacement and multiple valve replacement patients. Age (years) Sex Male, n Female, n NYHA class II, n III, n IV, n AF, n (%) PAH, n (%) OSA, n (%) CSA, n (%) LVEF (%) 6MWT distance (m) Duration of surgery (min) Duration of CBP (min) Length of ICU stay (h) Duration of mechanical ventilation (h) Pacemaker use, n (%) Length of hospital stay (day) Length after surgery (day)
Single Valve Replacement (n = 133) 51.5 ± 11.9
Multiple Valve Replacement (n = 157) 51.3 ± 9.0
66 67
p value 0.875 < 0.001
60 97 < 0.001
41 77 15 40 (30) 29 (22) 29 (22) 24 (18) 62.6 ± 6.6 338.6 ± 69.5 245.6 ± 68.4 109.0 ± 42.9 22 (19, 42) 17 (12, 19) 9 (16.7) 26.4 ± 8.7 14.3 ± 5.7
5 111 41 110 (70) 50 (32) 27 (17) 37 (24) 61.1 ± 7.0 321.9 ± 72.1 266.8 ± 61.6 124.8 ± 40.9 23 (20, 43) 17 (13, 19) 25 (41.0) 28.8 ± 8.4 14.9 ± 5.4
< 0.001 0.056 0.322 0.250 0.070 0.047 0.006 0.001 0.584# 0.835# 0.002 0.017 0.407
Data are presented as n (%), mean ± standard deviation or median (Q1, Q3). *p < 0.05, OSA or CSA vs. no SDB; # p < 0.05, CSA vs. OSA. OSA, obstructive sleep apnea; CSA, central sleep apnea; NYHA, New York Heart Association; AF, atrial fibrillation; PAH, pulmonary hypertension; LVEF, left ventricular ejection fraction; 6MWT, six-minute walk test; CBP, cardiopulmonary bypass; ICU, intensive care unit.
of long-term follow-up and no continuous positive airway pressure (CPAP) treatment. Our further studies are going to be performed under the following topics: (1) Sleep apnea and long-time outcomes in patients undergoing cardiac valve replacement surgery, (2) Association between preoperative CPAP treatment and postoperative complications in patients undergoing cardiac valve replacement surgery. The valuable comments and suggestions from Dr. Antonio Maria Esquinas and Luca Salvatore De Santo will be taken into consideration in our further studies.
LVEF, left ventricular ejection fraction MVR, mitral valve replacement NYHA, New York Heart Association OSA, obstructive sleep apnea PAH, pulmonary hypertension TVR, tricuspid valve replacement R E FE R E N CES
C I TAT I O N Ding N, Ni BQ, Wang H, Zhang SJ, Zhang XL. Obstructive sleep apnea: a risk factor of cardiac valve replacement surgery. J Clin Sleep Med 2016;12(11):1573–1575. A B B R E V I AT I O N S 6MWT, six-minute walk test AF, atrial fibrillation AVR, aortic valve replacement CAD, coronary artery disease COPD, chronic obstructive pulmonary disease CPAP, continuous positive airway pressure CSA, central sleep apnea Journal of Clinical Sleep Medicine, Vol. 12, No. 11, 2016
1574
1. Esquinas AM, De Santo LS. Impact of sleep-disordered breathing on postoperative outcomes: another brick in the wall. J Clin Sleep Med 2016;12:1571. 2. Ding N, Ni BQ, Wang H, et al. Obstructive sleep apnea increases the perioperative risk of cardiac valve replacement surgery: a prospective singlecenter study. J Clin Sleep Med 2016;12:1331–7. 3. Ding N, Ni BQ, Zhang XL et al. Prevalence and risk factors of sleep disordered breathing in patients with rheumatic valvular heart disease. J Clin Sleep Med 2013;9:781–7. 4. Foldvary-Schaefer N, Kaw R, Collop N, et al. Prevalence of undetected sleep apnea in patients undergoing cardiovascular surgery and impact on postoperative outcomes. J Clin Sleep Med 2015;11:1083–9. 5. Melby SJ, Moon MR, Lindman BR, Bailey MS, Hill LL, Damiano RJ Jr. Impact of pulmonary hypertension on outcomes after aortic valve replacement for aortic valve stenosis. J Thorac Cardiovasc Surg 2011;141:1424–30. 6. Kaw R, Pasupuleti V, Walker E, Ramaswamy A, Foldvary-Schafer N. Postoperative complications in patients with obstructive sleep apnea. Chest 2012;2:436–41. 7. Mokhlesi B, Hovda MD, Vekhter B, Arora VM, Chung F, Meltzer DO. Sleepdisordered breathing and postoperative outcomes after elective surgery: analysis of the nationwide inpatient sample. Chest 2013;3:903–14.
N Ding, BQ Ni, H Wang et al. Letter to the Editor 8. Uchôa CH, Danzi-Soares Nde J, Nunes FS, et al. Impact of OSA on cardiovascular events after coronary artery bypass surgery. Chest 2015;5:1352–60. 9. Kaw R, Golish J, Ghamande S, Burgess R, Foldvary N, Walker E. Incremental risk of obstructive sleep apnea on cardiac surgical outcomes. J Cardiovasc Surg (Torino) 2006;6:683–9. 10. Fortis S, Colling KP, Statz CL, Glover JJ, Radosevich DM, Beilman GJ. Obstructive sleep apnea: a risk factor for surgical site infection following colectomy. Surg Infect (Larchmt) 2015;5:611–7.
Address correspondence to: Shi-Jiang Zhang, PhD, MD, Department of Cardiovascular Surgery, the First Affiliated Hospital of Nanjing Medical University, Guangzhou 300 Road, Nanjing, 210029, China; Tel: (86) 02583673066; Fax: (86) 02583673066; Email: [email protected] or Xing-Long Zhang, PhD, MD, Department of Respiratory and Critical Care Medicine, the First Affiliated Hospital of Nanjing Medical University, 300 Guangzhou Road, Nanjing 210029, China; Tel: (86) 02568136723; Fax: (86) 02568136723; Email: [email protected]
D I SCLO S U R E S TAT E M E N T
SUBM I SSI O N & CO R R ESPO NDENCE I NFO R M ATI O N
The authors have indicated no financial conflicts of interest.
Submitted for publication October, 2016 Accepted for publication October, 2016
1575
Journal of Clinical Sleep Medicine, Vol. 12, No. 11, 2016
LE TTER S TO T H E EDITOR
Obstructive Sleep Apnea: A Risk Factor of Cardiac Valve Replacement Surgery Response to Esquinas and De Santo. Impact of sleep-disordered breathing on postoperative outcomes: another brick in the wall. J Clin Sleep Med 2016;12(11):1571. Ning Ding1; Bu-Qing Ni2; Hong Wang1; Shi-Jiang Zhang, PhD, MD2; Xi-Long Zhang, PhD, MD1 Department of Respiratory and Critical Care Medicine, the First Affiliated Hospital of Nanjing Medical University, Nanjing, China; 2Department of Cardiovascular Surgery, the First Affiliated Hospital of Nanjing Medical University, Nanjing, China
1
We thank Dr. Antonio Maria Esquinas and Luca Salvatore De Santo1 for their interest and commentary regarding our manuscript detailing obstructive sleep apnea (OSA) increases the perioperative risk of cardiac valve replacement surgery. We also are thankful for the opportunity to clarify some limitations in our study. This article2 is one of our series of studies on “sleep apnea and valvular heart disease.” In our previous publication,3 we gave a detailed description about the difference among patients with various kinds of valvular lesions. Since in this study we focused on the correlation between sleep apnea and postoperative complications, special attention was not paid to the difference in types of cardiac valvular surgery. Here, we listed the types of cardiac valvular surgery in Table 1 and compared the clinical parameters between single valve replacement and multiple valve replacement patients in Table 2. In addition, the correlations were analyzed about types of cardiac valve replacement and postoperative adverse events, in which we found that when comparing with single valve replacement, multiple valve replacement did not increase ICU length of stay and duration of mechanical ventilation. In some previous studies,4,5 the preoperative baseline diseases of their study patients such as hypertension, diabetes mellitus, stroke, coronary artery disease (CAD) and chronic obstructive pulmonary disease (COPD) were described. In our study population, there are 10 (3.4%) patients combined with hypertension, 5 (1.7%) combined with diabetes, 5 (1.7%) combined with stroke, 15 (5.2%) combined with left atrial thrombi, 24 (8.3%) combined with CAD, and 2 (0.7%) combined with COPD. Excuse us for our carelessness, when we designed the study, we failed to take intraoperative blood management into consideration. Therefore, the data about blooding volume/ transfusion blood volume were devoid in this study. This is a limitation of our study. Our selection of postoperative adverse outcomes was based on some studies.6,7 We set up six adverse outcomes at beginning of the study: ICU length of stay ≥ 25 h, mechanical ventilation ≥ 20 h, pacemaker use, cardiopulmonary bypass ≥ 110 min, first dose of dopamine in ICU ≥ 3 μg/kg·min and first dose of dobutamine in ICU ≥ 3 μg/kg·min. However, because of the suggestions from reviewers and editors as well as the following reasons: 1) cardiopulmonary bypass ≥ 110 1573
min was more associated with the complex of cardiac surgery itself rather than perioperative risks; 2) both first dose of dopamine in ICU ≥ 3 µg/kg·min and first dose of dobutamine in ICU ≥ 3 µg/kg·min were more closely related to preoperative cardiac function and bleeding amount during surgery rather than perioperative risks, the adverse events of cardiopulmonary bypass ≥ 110 min, first dose of dopamine in ICU ≥ 3 μg/ kg·min and first dose of dobutamine in ICU ≥ 3 μg/kg·min were deleted. Finally, only the following three outcomes were kept: ICU length of stay ≥ 25 h (reflect overall worsening of postoperative recovery), mechanical ventilation ≥ 20 h (reflect postoperative respiratory insufficiency) and pacemaker use (reflect severe cardiac arrhythmia). Other postoperative adverse events such as reintubation, infection, pneumonia, myocardial infarction,4,6,8-10 were not included in our original protocol and failed to be recorded in our study as well. This limitation will push us to pursue more proper observation in our further study in the future. In spite of this, we have, to say the least, detected the phenomenon that preoperative OSA could increase the perioperative risk of cardiac valve replacement surgery. This finding might remind surgeons to consider sleep apnea in preoperative evaluation and postoperative management. Apart from the limitations mentioned above, there are another two important limitations mentioned in this article, lack
Table 1—Types of heart valve replacement. MVR TVR AVR MVR+TVR MVR+AVR TVR+AVR MVR+TVR+AVR Total
Case 90 5 38 73 34 3 47 290
% 31.0 1.7 13.1 25.2 11.7 1.0 16.2 100.0
MVR, mitral valve replacement; TVR, tricuspid valve replacement; AVR, aortic valve replacement
Journal of Clinical Sleep Medicine, Vol. 12, No. 11, 2016
N Ding, BQ Ni, H Wang et al. Letter to the Editor
Table 2—Comparisons of clinical parameters between single valve replacement and multiple valve replacement patients. Age (years) Sex Male, n Female, n NYHA class II, n III, n IV, n AF, n (%) PAH, n (%) OSA, n (%) CSA, n (%) LVEF (%) 6MWT distance (m) Duration of surgery (min) Duration of CBP (min) Length of ICU stay (h) Duration of mechanical ventilation (h) Pacemaker use, n (%) Length of hospital stay (day) Length after surgery (day)
Single Valve Replacement (n = 133) 51.5 ± 11.9
Multiple Valve Replacement (n = 157) 51.3 ± 9.0
66 67
p value 0.875 < 0.001
60 97 < 0.001
41 77 15 40 (30) 29 (22) 29 (22) 24 (18) 62.6 ± 6.6 338.6 ± 69.5 245.6 ± 68.4 109.0 ± 42.9 22 (19, 42) 17 (12, 19) 9 (16.7) 26.4 ± 8.7 14.3 ± 5.7
5 111 41 110 (70) 50 (32) 27 (17) 37 (24) 61.1 ± 7.0 321.9 ± 72.1 266.8 ± 61.6 124.8 ± 40.9 23 (20, 43) 17 (13, 19) 25 (41.0) 28.8 ± 8.4 14.9 ± 5.4
< 0.001 0.056 0.322 0.250 0.070 0.047 0.006 0.001 0.584# 0.835# 0.002 0.017 0.407
Data are presented as n (%), mean ± standard deviation or median (Q1, Q3). *p < 0.05, OSA or CSA vs. no SDB; # p < 0.05, CSA vs. OSA. OSA, obstructive sleep apnea; CSA, central sleep apnea; NYHA, New York Heart Association; AF, atrial fibrillation; PAH, pulmonary hypertension; LVEF, left ventricular ejection fraction; 6MWT, six-minute walk test; CBP, cardiopulmonary bypass; ICU, intensive care unit.
of long-term follow-up and no continuous positive airway pressure (CPAP) treatment. Our further studies are going to be performed under the following topics: (1) Sleep apnea and long-time outcomes in patients undergoing cardiac valve replacement surgery, (2) Association between preoperative CPAP treatment and postoperative complications in patients undergoing cardiac valve replacement surgery. The valuable comments and suggestions from Dr. Antonio Maria Esquinas and Luca Salvatore De Santo will be taken into consideration in our further studies.
LVEF, left ventricular ejection fraction MVR, mitral valve replacement NYHA, New York Heart Association OSA, obstructive sleep apnea PAH, pulmonary hypertension TVR, tricuspid valve replacement R E FE R E N CES
C I TAT I O N Ding N, Ni BQ, Wang H, Zhang SJ, Zhang XL. Obstructive sleep apnea: a risk factor of cardiac valve replacement surgery. J Clin Sleep Med 2016;12(11):1573–1575. A B B R E V I AT I O N S 6MWT, six-minute walk test AF, atrial fibrillation AVR, aortic valve replacement CAD, coronary artery disease COPD, chronic obstructive pulmonary disease CPAP, continuous positive airway pressure CSA, central sleep apnea Journal of Clinical Sleep Medicine, Vol. 12, No. 11, 2016
1574
1. Esquinas AM, De Santo LS. Impact of sleep-disordered breathing on postoperative outcomes: another brick in the wall. J Clin Sleep Med 2016;12:1571. 2. Ding N, Ni BQ, Wang H, et al. Obstructive sleep apnea increases the perioperative risk of cardiac valve replacement surgery: a prospective singlecenter study. J Clin Sleep Med 2016;12:1331–7. 3. Ding N, Ni BQ, Zhang XL et al. Prevalence and risk factors of sleep disordered breathing in patients with rheumatic valvular heart disease. J Clin Sleep Med 2013;9:781–7. 4. Foldvary-Schaefer N, Kaw R, Collop N, et al. Prevalence of undetected sleep apnea in patients undergoing cardiovascular surgery and impact on postoperative outcomes. J Clin Sleep Med 2015;11:1083–9. 5. Melby SJ, Moon MR, Lindman BR, Bailey MS, Hill LL, Damiano RJ Jr. Impact of pulmonary hypertension on outcomes after aortic valve replacement for aortic valve stenosis. J Thorac Cardiovasc Surg 2011;141:1424–30. 6. Kaw R, Pasupuleti V, Walker E, Ramaswamy A, Foldvary-Schafer N. Postoperative complications in patients with obstructive sleep apnea. Chest 2012;2:436–41. 7. Mokhlesi B, Hovda MD, Vekhter B, Arora VM, Chung F, Meltzer DO. Sleepdisordered breathing and postoperative outcomes after elective surgery: analysis of the nationwide inpatient sample. Chest 2013;3:903–14.
N Ding, BQ Ni, H Wang et al. Letter to the Editor 8. Uchôa CH, Danzi-Soares Nde J, Nunes FS, et al. Impact of OSA on cardiovascular events after coronary artery bypass surgery. Chest 2015;5:1352–60. 9. Kaw R, Golish J, Ghamande S, Burgess R, Foldvary N, Walker E. Incremental risk of obstructive sleep apnea on cardiac surgical outcomes. J Cardiovasc Surg (Torino) 2006;6:683–9. 10. Fortis S, Colling KP, Statz CL, Glover JJ, Radosevich DM, Beilman GJ. Obstructive sleep apnea: a risk factor for surgical site infection following colectomy. Surg Infect (Larchmt) 2015;5:611–7.
Address correspondence to: Shi-Jiang Zhang, PhD, MD, Department of Cardiovascular Surgery, the First Affiliated Hospital of Nanjing Medical University, Guangzhou 300 Road, Nanjing, 210029, China; Tel: (86) 02583673066; Fax: (86) 02583673066; Email: [email protected] or Xing-Long Zhang, PhD, MD, Department of Respiratory and Critical Care Medicine, the First Affiliated Hospital of Nanjing Medical University, 300 Guangzhou Road, Nanjing 210029, China; Tel: (86) 02568136723; Fax: (86) 02568136723; Email: [email protected]
D I SCLO S U R E S TAT E M E N T
SUBM I SSI O N & CO R R ESPO NDENCE I NFO R M ATI O N
The authors have indicated no financial conflicts of interest.
Submitted for publication October, 2016 Accepted for publication October, 2016
1575
Journal of Clinical Sleep Medicine, Vol. 12, No. 11, 2016
