156
Letters to the Editor
Assessing Morbidity and Mortality Following Total Hip Arthroplasty
To the Editor: The recent article by Belmont et al [1] assessing the risk factors and incidence of 30-day morbidity and mortality following total hip arthroplasty was of great interest to us. They showed that age ≥ 70, renal insufficiency, cardiac diseases, ASA physical status classification ≥ 3, and male sex were significant predictors for mortality. Moreover, age ≥ 80 years, ASA physical status classification ≥ 3 and cardiac diseases were predictors of developing any postoperative complication, as well as major systemic complications. The power of this study is its use of a large dataset from the American College of Surgeons National Surgical Quality Improvement Program containing most of the known factors that can affect perioperative morbidity and mortality of such surgical patients. Furthermore, the authors have rightly used univariate and multivariate logistic regression analyses to identify the risk factors of postoperative morbidity and mortality, and openly discussed some limitations of their work. However, this study is a retrospective analysis, which is inevitably subject to uncontrolled and unmeasured confounding. In our view, several important issues of this study were not well addressed. First, perioperative hemoglobin levels and transfusion were not included in the risk factors of perioperative morbidity and mortality. A systematic review of the literature shows that perioperative anemia is highly prevalent in patients undergoing total hip arthroplasty, and is significantly associated with adverse clinical outcomes and increased postoperative mortality [2]. Other than the inherent infectious, immunologic and pulmonary risks, transfusion has also been shown to be an independent predictor of increased postoperative mortality in patients undergoing hip and knee replacement [3]. Second, adverse cardiac events are the leading causes of perioperative mortality, and about 60% of studied populations have preoperative cardiovascular comorbidities, such as congestive heart failure, myocardial infarction, and hypertension. Did the dataset from which Belmont et al [1] retrieved information for analysis contain patients’ perioperative cardiac medications? If it did, they should assess possible effects of these confounding factors on postoperative morbidity and mortality. It has been shown that perioperative ACE inhibitors, β-blockers and statins are significantly associated with reduced hospital and longterm mortality in patients undergoing noncardiac surgery [4], whereas discontinuation of β-blocker prescription during first week following surgery is significantly associated with increased myocardial infarction and death in patients undergoing hip or knee arthroplasty [5]. Third, we are not provided with details of anesthesia and intraoperative managements. Consequently, it is difficult to estimate the extent to which interventions by anesthetists might have influenced postoperative morbidity and mortality. It has been shown that intraoperative hypoxemia, hypotension, tachycardia and hypertension are associated independently with morbidity and mortality following noncardiac surgery [6,7]. Actually, even short durations of an intraoperative MAP b 55 mmHg can result in postoperative myocardial injury, and there is an independent graded relationship between duration of intraoperative hypotension and postoperative myocardial injury and cardiac morbidity [8]. In comparison with alone preoperative risk stratification indices, moreover, the inclusion of intraoperative elements can improve the ability to predict perioperative mortality and adverse cardiac events [7]. Finally, patients’ mobility ability and functional status before surgery were not provided and analyzed. Actually, preoperative impaired functional status and mobility disability are common among patients undergoing total hip arthroplasty. Obviously, such conditions can not only impair patient survival, but also may adversely affect recovery and clinical The Conflict of Interest statement associated with this article can be found at http://dx.doi.org/10.1016/j.arth.2014.09.001.
outcome. Specifically, mobility disability has been shown to be a strong independent predictor of postoperative mortality in patients undergoing hip and knee replacements [3]. Thus, we cannot exclude possibility that mobility disability is a serious health problem of their studied patients and contributes to postoperative mortality and complications. We believe that their results would have been more informative if the above factors were taken into account. Qun Ma, MD Department of Plastic Surgery, Siping Central People’s Hospital Jilin Province, People’s Republic of China Fu Shan Xue, MD Shi Yu Wang, MD Department of Anesthesiology, Plastic Surgery Hospital Chinese Academy of Medical Sciences and Peking Union Medical College Beijing, China
http://dx.doi.org/10.1016/j.arth.2014.09.001
References 1. Belmont Jr PJ, Goodman GP, Hamilton W, et al. Morbidity and mortality in the thirtyday period following total hip arthroplasty: risk factors and incidence. J Arthroplasty 2014. http://dx.doi.org/10.1016/j.arth.2014.05.015 [in press]. 2. Spahn DR. Anemia and patient blood management in hip and knee surgery: a systematic review of the literature. Anesthesiology 2010;113:482. 3. Jämsen E, Puolakka T, Eskelinen A, et al. Predictors of mortality following primary hip and knee replacement in the aged. A single-center analysis of 1,998 primary hip and knee replacements for primary osteoarthritis. Acta Orthop 2013;84:44. 4. Feringa HH, Bax JJ, Karagiannis SE, et al. Elderly patients undergoing major vascular surgery: risk factors and medication associated with risk reduction. Arch Gerontol Geriatr 2009;48:116. 5. van Klei WA, Bryson GL, Yang H, et al. Effect of β-blocker prescription on the incidence of postoperative myocardial infarction after hip and knee arthroplasty. Anesthesiology 2009;111:717. 6. Kheterpal S, O'Reilly M, Englesbe MJ, et al. Preoperative and intraoperative predictors of cardiac adverse events after general, vascular, and urological surgery. Anesthesiology 2009;110:58. 7. Reich DL, Bennett-Guerrero E, Bodian CA, et al. Intraoperative tachycardia and hypertension are independently associated with adverse outcome in noncardiac surgery of long duration. Anesth Analg 2002;95:273. 8. Walsh M, Devereaux PJ, Garg AX, et al. Relationship between intraoperative mean arterial pressure and clinical outcomes after noncardiac surgery: toward an empirical definition of hypotension. Anesthesiology 2013;119:507.
Letter to the Editor on “Can Total Knee Arthroplasty Be Safely Performed Among Nonagenarians? An Evaluation of Morbidity and Mortality Within a Total Joint Replacement Registry” To the Editor: We are impressed with the recent publication titled “Can total knee arthroplasty (TKA) be safely performed among nonagenarians [1]?” This study has validated our belief that reconstructive surgery like TKA can be performed relatively safely in selected patients above 90 years of age. The authors have discussed a lot of relevant points but have not mentioned a few facts in this retrospective cohort study, which seem relevant to most surgeons who would like to embark on surgery in nonagenarians: 1) It is not described if the TKA was done in single knee or for both knees simultaneously or in staged manner. This is important because most of the patients would have had bilateral knee arthritis. There are various advantages of doing simultaneous bilateral TKA like a shorter time of exposure to anesthesia, less hospital stay, shorter The Conflict of Interest statement associated with this article can be found at http://dx.doi.org/10.1016/j.arth.2014.09.017.
Letters to the Editor
Assessing Morbidity and Mortality Following Total Hip Arthroplasty
To the Editor: The recent article by Belmont et al [1] assessing the risk factors and incidence of 30-day morbidity and mortality following total hip arthroplasty was of great interest to us. They showed that age ≥ 70, renal insufficiency, cardiac diseases, ASA physical status classification ≥ 3, and male sex were significant predictors for mortality. Moreover, age ≥ 80 years, ASA physical status classification ≥ 3 and cardiac diseases were predictors of developing any postoperative complication, as well as major systemic complications. The power of this study is its use of a large dataset from the American College of Surgeons National Surgical Quality Improvement Program containing most of the known factors that can affect perioperative morbidity and mortality of such surgical patients. Furthermore, the authors have rightly used univariate and multivariate logistic regression analyses to identify the risk factors of postoperative morbidity and mortality, and openly discussed some limitations of their work. However, this study is a retrospective analysis, which is inevitably subject to uncontrolled and unmeasured confounding. In our view, several important issues of this study were not well addressed. First, perioperative hemoglobin levels and transfusion were not included in the risk factors of perioperative morbidity and mortality. A systematic review of the literature shows that perioperative anemia is highly prevalent in patients undergoing total hip arthroplasty, and is significantly associated with adverse clinical outcomes and increased postoperative mortality [2]. Other than the inherent infectious, immunologic and pulmonary risks, transfusion has also been shown to be an independent predictor of increased postoperative mortality in patients undergoing hip and knee replacement [3]. Second, adverse cardiac events are the leading causes of perioperative mortality, and about 60% of studied populations have preoperative cardiovascular comorbidities, such as congestive heart failure, myocardial infarction, and hypertension. Did the dataset from which Belmont et al [1] retrieved information for analysis contain patients’ perioperative cardiac medications? If it did, they should assess possible effects of these confounding factors on postoperative morbidity and mortality. It has been shown that perioperative ACE inhibitors, β-blockers and statins are significantly associated with reduced hospital and longterm mortality in patients undergoing noncardiac surgery [4], whereas discontinuation of β-blocker prescription during first week following surgery is significantly associated with increased myocardial infarction and death in patients undergoing hip or knee arthroplasty [5]. Third, we are not provided with details of anesthesia and intraoperative managements. Consequently, it is difficult to estimate the extent to which interventions by anesthetists might have influenced postoperative morbidity and mortality. It has been shown that intraoperative hypoxemia, hypotension, tachycardia and hypertension are associated independently with morbidity and mortality following noncardiac surgery [6,7]. Actually, even short durations of an intraoperative MAP b 55 mmHg can result in postoperative myocardial injury, and there is an independent graded relationship between duration of intraoperative hypotension and postoperative myocardial injury and cardiac morbidity [8]. In comparison with alone preoperative risk stratification indices, moreover, the inclusion of intraoperative elements can improve the ability to predict perioperative mortality and adverse cardiac events [7]. Finally, patients’ mobility ability and functional status before surgery were not provided and analyzed. Actually, preoperative impaired functional status and mobility disability are common among patients undergoing total hip arthroplasty. Obviously, such conditions can not only impair patient survival, but also may adversely affect recovery and clinical The Conflict of Interest statement associated with this article can be found at http://dx.doi.org/10.1016/j.arth.2014.09.001.
outcome. Specifically, mobility disability has been shown to be a strong independent predictor of postoperative mortality in patients undergoing hip and knee replacements [3]. Thus, we cannot exclude possibility that mobility disability is a serious health problem of their studied patients and contributes to postoperative mortality and complications. We believe that their results would have been more informative if the above factors were taken into account. Qun Ma, MD Department of Plastic Surgery, Siping Central People’s Hospital Jilin Province, People’s Republic of China Fu Shan Xue, MD Shi Yu Wang, MD Department of Anesthesiology, Plastic Surgery Hospital Chinese Academy of Medical Sciences and Peking Union Medical College Beijing, China
http://dx.doi.org/10.1016/j.arth.2014.09.001
References 1. Belmont Jr PJ, Goodman GP, Hamilton W, et al. Morbidity and mortality in the thirtyday period following total hip arthroplasty: risk factors and incidence. J Arthroplasty 2014. http://dx.doi.org/10.1016/j.arth.2014.05.015 [in press]. 2. Spahn DR. Anemia and patient blood management in hip and knee surgery: a systematic review of the literature. Anesthesiology 2010;113:482. 3. Jämsen E, Puolakka T, Eskelinen A, et al. Predictors of mortality following primary hip and knee replacement in the aged. A single-center analysis of 1,998 primary hip and knee replacements for primary osteoarthritis. Acta Orthop 2013;84:44. 4. Feringa HH, Bax JJ, Karagiannis SE, et al. Elderly patients undergoing major vascular surgery: risk factors and medication associated with risk reduction. Arch Gerontol Geriatr 2009;48:116. 5. van Klei WA, Bryson GL, Yang H, et al. Effect of β-blocker prescription on the incidence of postoperative myocardial infarction after hip and knee arthroplasty. Anesthesiology 2009;111:717. 6. Kheterpal S, O'Reilly M, Englesbe MJ, et al. Preoperative and intraoperative predictors of cardiac adverse events after general, vascular, and urological surgery. Anesthesiology 2009;110:58. 7. Reich DL, Bennett-Guerrero E, Bodian CA, et al. Intraoperative tachycardia and hypertension are independently associated with adverse outcome in noncardiac surgery of long duration. Anesth Analg 2002;95:273. 8. Walsh M, Devereaux PJ, Garg AX, et al. Relationship between intraoperative mean arterial pressure and clinical outcomes after noncardiac surgery: toward an empirical definition of hypotension. Anesthesiology 2013;119:507.
Letter to the Editor on “Can Total Knee Arthroplasty Be Safely Performed Among Nonagenarians? An Evaluation of Morbidity and Mortality Within a Total Joint Replacement Registry” To the Editor: We are impressed with the recent publication titled “Can total knee arthroplasty (TKA) be safely performed among nonagenarians [1]?” This study has validated our belief that reconstructive surgery like TKA can be performed relatively safely in selected patients above 90 years of age. The authors have discussed a lot of relevant points but have not mentioned a few facts in this retrospective cohort study, which seem relevant to most surgeons who would like to embark on surgery in nonagenarians: 1) It is not described if the TKA was done in single knee or for both knees simultaneously or in staged manner. This is important because most of the patients would have had bilateral knee arthritis. There are various advantages of doing simultaneous bilateral TKA like a shorter time of exposure to anesthesia, less hospital stay, shorter The Conflict of Interest statement associated with this article can be found at http://dx.doi.org/10.1016/j.arth.2014.09.017.
