UPDATE Update in Perioperative Medicine: Evidence Published in 2014 Karen F. Mauck, MD, MSc, and Karna K. Sundsted, MD
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his summary highlights 9 key articles in perioperative medicine published in 2014. To identify these articles, we searched PubMed by using the keywords “perioperative or preoperative or postoperative or noncardiac surgery (NCS)” and limiting the search to a publication date of 2014, human study subjects, and English language. We then screened the 14 771 resulting abstracts. In addition, we used ACP JournalWise to identify high-quality, clinically relevant publications related to perioperative care. Fifty-six unique full-text articles were considered for inclusion. In selecting the 9 articles to highlight, we used the predetermined criteria of clinical relevance to internal medicine physicians, potential for practice change, and strength of the evidence. We gave priority to practice guidelines or meta-analyses that addressed clinical questions important to perioperative care. The selected represent topic areas ranging from perioperative cardiac and pulmonary medicine to venous thromboembolism prophylaxis and medication management.
Perioperative Cardiac Medicine Updated Guideline on Perioperative Cardiovascular Evaluation Fleisher LA, Fleischmann KE, Auerbach AD, et al. 2014 ACC/ AHA guideline on perioperative cardiovascular evaluation and management of patients undergoing noncardiac surgery: a report of the American College of Cardiology/American Heart Association Task Force on practice guidelines. J Am Coll Cardiol. 2014;64:e77-137. [PMID: 25091544] doi:10. 1016/j.jacc.2014.07.944
Background: The American College of Cardiology (ACC)/American Heart Association (AHA) guideline provides evidence- and expert opinion– based recommendations for preoperative risk assessment, cardiovascular testing, perioperative pharmacologic management, timing of surgery after percutaneous intervention, and perioperative monitoring of patients with (or at risk for) cardiovascular disease who undergo NCS. Findings: The guideline recommends an algorithmic approach to preoperative cardiac risk assessment to help determine whether cardiac stress testing is indicated. The suggested algorithm incorporates 1) surgical urgency, 2) presence of acute coronary syndromes, 3) combined clinical and surgery-specific risk for major adverse cardiac events (as determined by using the American College of Surgeons National Surgical Quality Improvement Program calculator [1] or the Revised
Cardiac Risk Index [RCRI] [2, 3]), and 4) functional capacity in metabolic equivalents. For non–low-risk surgical procedures, electrocardiography (ECG) is reasonable in patients with coronary or peripheral artery disease, arrhythmia, cerebrovascular disease, or structural heart disease, and preoperative assessment of left ventricular function is reasonable in patients with dyspnea or unstable heart failure symptoms. Coronary revascularization before NCS is recommended only if indicated outside of the surgical context and not exclusively to reduce perioperative risk. Optimal delays in surgery are 1 year after placement of a drug-eluting stent, 30 days after placement of a bare-metal stent, and 14 days after balloon angioplasty, to allow uninterrupted dual-antiplatelet therapy. Dual-antiplatelet therapy should be continued in patients undergoing urgent NCS during the first 4 to 6 weeks after placement of a bare-metal stent or drugeluting stent unless the risk for bleeding outweighs the risk for stent thrombosis. If dual-antiplatelet therapy is interrupted, use of aspirin should be continued and full therapy resumed as soon as possible after surgery. Patients who receive -blockers or statins on a long-term basis should continue to do so in the perioperative period. It may be reasonable to initiate treatment with -blockers in the perioperative period for patients with ischemia or more than 3 RCRI risk factors, but initiation should take place long enough in advance of surgery to assess safety and tolerability and should not occur on the day of surgery. It is reasonable to initiate statin therapy preoperatively in patients undergoing vascular surgery or a non–low-risk surgery who have at least 1 RCRI risk factor. Troponin measurement and ECG are recommended only for patients with signs or symptoms of cardiac ischemia. Cautions: Where randomized, controlled trial (RCT) evidence was unavailable, recommendations were based on observational data or expert opinion. Implications: Clinicians who provide perioperative care should familiarize themselves with this guideline.
Careful Patient Selection Is Needed When Considering Perioperative -Blockers Blessberger H, Kammler J, Domanovits H, et al. Perioperative beta-blockers for preventing surgery-related mortality and morbidity. Cochrane Database Syst Rev. 2014;9:CD004476. [PMID: 25233038] doi:10.1002/14651858.CD004476.pub2
Background: The 2014 ACC/AHA guidelines on perioperative cardiovascular evaluation and management added a Class III harm recommendation against starting -blockers on the day of surgery (4), and a more
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UPDATE conservative approach is recommended for initiation of -blocker therapy in high-risk patients. However, questions remain, including whether certain patients may benefit from perioperative -blockade. Findings: This systematic review of 89 RCTs (19 211 participants) analyzed cardiac surgery and NCS populations separately. In cardiac surgery (53 trials), there was no increase in 30-day all-cause mortality among patients taking -blockers versus those who were not (relative risk [RR], 0.73 [95% CI, 0.35 to 1.52]). In addition, no significant difference was found for many secondary outcomes in the cardiac surgery group, including acute myocardial infarction (MI) (RR, 1.04 [CI, 0.71 to 1.51]) and myocardial ischemia (RR, 0.51 [CI, 0.25 to 1.05]). -Blockers did significantly reduce the occurrence of ventricular and supraventricular tachycardias in cardiac surgery patients. In NCS (36 trials), -blockers potentially increased 30-day all-cause mortality (RR, 1.27 [CI, 1.01 to 1.59]) and cerebrovascular events (RR, 1.59 [CI, 0.93 to 2.71)], but they significantly reduced the occurrence of acute MI (RR, 0.73 [CI, 0.61 to 0.87]) and myocardial ischemia (RR, 0.43 [CI, 0.27 to 0.70]) while increasing the risk for bradycardia and hypotension. Cautions: Most of the results in this meta-analysis were driven by 1 large trial: POISE (PeriOperative ISchemic Evaluation) (5), which represented 71% of the weight of the meta-analysis. In the POISE trial, a generous dose of long-acting -blocker was administered 2 to 4 hours before surgery and postoperatively. Sensitivity analyses were conducted with and without the POISE trial results to account for this. Implications: This review highlights the continued need for careful patient selection and caution with regard to perioperative use of -blockers. There may be less risk and more potential benefit in cardiac surgery patients. There is also potential risk reduction with regard to perioperative acute MI and cardiac ischemia in NCS patients, but this must be carefully weighed against the possible increased risk for mortality, stroke, and hemodynamic instability. If -blocker therapy is started preoperatively, the meta-analysis highlights the importance of allowing enough time after initiation for dose titration and assessment of medication tolerance.
Postoperative Troponin Elevation Has Myocardial Injury Implications After NCS Botto F, Alonso-Coello P, Chan MT, et al; Vascular events In noncardiac Surgery patients cOhort evaluatioN (VISION) Writing Group. Myocardial injury after noncardiac surgery: a large, international, prospective cohort study establishing diagnostic criteria, characteristics, predictors, and 30-day outcomes. Anesthesiology. 2014;120:564-78. [PMID: 24534856] doi:10.1097/ALN.0000000000000113
Background: Whether troponin levels should be obtained postoperatively in the absence of ischemic symptoms presents a clinical conundrum. Data, including those from this study, have demonstrated an association between asymptomatic elevated troponin levels postoperatively and 30-day mortality (6). However, the
Update in Perioperative Medicine
2014 ACC/AHA guideline on perioperative cardiovascular evaluation recommends against routine postoperative troponin screening in unselected patients and cites uncertain benefit in high-risk patients without ischemic symptoms (4). This study sought to define diagnostic criteria, characteristics, predictors, and 30-day outcomes of myocardial injury after NCS (MINS). Findings: This international prospective cohort study included 15 065 participants aged 45 years or older who underwent NCS requiring at least overnight observation. Patients with elevated postoperative troponin T levels were assessed for ischemic ECG changes or ischemic symptoms. With a cutoff value for troponin T of 0.03 ng/mL or greater, 1200 patients (8%) met the criteria for MINS. The primary outcome was postoperative 30-day mortality; rates were 9.8% among patients with MINS compared with 1.1% among patients without MINS (odds ratio [OR], 10.07 [CI, 7.84 to 12.94]). Four perioperative complications (MINS, sepsis, stroke, and pulmonary embolism) were independent predictors of 30day mortality in multivariate analysis. Not unexpectedly, 87.1% of MINS events occurred within the first 2 days of surgery. Among patients who met the criteria for MINS, 84.2% did not experience ischemic symptoms and 58% did not fulfill the universal definition of MI. Patients with MINS were also at higher risk for nonfatal cardiac arrest, congestive heart failure, and stroke. Cautions: This study design is able to establish an association between mortality and other adverse events in patients with MINS, but it cannot definitively establish a causal relationship. It also does not tell us whether intervention when the troponin T level is elevated would improve outcomes. Implications: The results of this study suggest that regardless of ischemic features, postoperative elevation of the troponin T level is relatively common and has important prognostic implications. The significant number of patients with MINS (over one half of whom were completely asymptomatic) and the associated 10-fold increase in 30-day mortality calls into question the current practice of clinically dismissing minor elevations of the troponin T level in the postoperative period. We agree with the study investigators that additional clinical trials are needed to better define interventions to attenuate myocardial injury and perioperative mortality in patients with postoperative elevation of the troponin T level.
Guideline-Based Medical Management of Postoperative Elevated Troponin Levels Probably Improves Long-Term Outcomes Foucrier A, Rodseth R, Aissaoui M, et al. The long-term impact of early cardiovascular therapy intensification for postoperative troponin elevation after major vascular surgery. Anesth Analg. 2014;119:1053-63. [PMID: 24937347] doi:10.1213/ ANE.0000000000000302
Background: Postoperative elevation of the troponin level often occurs without symptoms or ECG changes suggestive of MI. Up to 65% of patients do not experi-
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ence ischemic symptoms with postoperative MI (6), and most cases go undiagnosed because current guidelines do not recommend routine postoperative surveillance with ECG and troponin measurement in asymptomatic patients (4). Although data suggest that routine monitoring of troponin levels in at-risk patients after surgery is needed to detect most MIs (which have an equally poor prognosis regardless of whether they are symptomatic or asymptomatic), whether early intervention in asymptomatic patients with elevated troponin levels will improve outcomes is uncertain. Findings: This case– control study identified 667 patients who underwent elective major vascular surgery. All patients had routine ECG and troponin I measurement on arrival to the postanesthetic care unit and on the first, second, and third postoperative days. Case patients (n = 66) were defined by an elevated troponin I level of 0.15 ng/mL or greater. Two control participants for each case patient were identified from the remaining patient pool (matched for RCRI score, age, sex, date, type of surgery, and presence of intraoperative complications). Case patients who had no modification of their cardiovascular treatment postoperatively (n = 23) were less likely to survive 1 year without experiencing a major cardiac event compared with the control group (hazard ratio [HR], 1.77 [CI, 1.13 to 2.42]). Case patients who did have therapeutic intensification (n = 43) were more likely to survive 1 year without experiencing a major cardiac event compared with the control group (HR, 0.63 [CI, 0.10 to 1.19]), but this finding was not statistically significant. Finally, patients with elevated troponin levels who did not receive treatment intensification were less likely to survive 1 year without experiencing a major cardiac event than were patients with elevated troponin levels who did receive treatment intensification (HR, 2.80 [CI, 1.05 to 24.20]). Cautions: This was a small observational study from a single institution involving only vascular surgery patients; generalizability to other types of surgery is limited. Elevation of the troponin level was the single criterion for case selection, with no discernment as to the cause of the elevation (cardiac or other). The study size did not allow for complete balance of preoperative risk factors among the groups despite propensity matching. Implications: Although no definite practice recommendations should be based on these observations, this is the first evidence to suggest that intensive treatment of a postoperative elevated troponin level with evidencebased medical management of acute coronary syndrome might improve long-term cardiac outcomes.
Neither Aspirin nor Clonidine Reduced the Risk for Death or Nonfatal MI in Patients Undergoing Noncardiac Surgery Devereaux PJ, Mrkobrada M, Sessler DI, et al; POISE-2 Investigators. Aspirin in patients undergoing noncardiac surgery. N Engl J Med. 2014;370:1494-503. [PMID: 24679062] doi: 10.1056/NEJMoa1401105
Background: Patients undergoing NCS may be at increased risk for perioperative complications, including MI, in part owing to platelet and sympathetic nervous system activation. Both aspirin and clonidine have been reported to decrease the risk for perioperative MI. However, substantial variability remains in the perioperative management of both medications, as well as concern about side effects. Findings: This RCT enrolled 10 010 patients using a 2 × 2 factorial design. Patients who had moderate or high risk for postoperative cardiac events were assigned to receive either 200 mg of aspirin or placebo 2 to 4 hours before surgery and 100 mg of aspirin or placebo daily up to 30 days after surgery; they were then assigned to receive either oral clonidine (0.2 mg) or placebo 2 to 4 hours before surgery and a clonidine patch (0.2 mg/d) or placebo patch that remained on for 72 hours postoperatively. The results for clonidine were reported in a separate article (7). The aspirin and clonidine groups did not differ with respect to the primary outcome (perioperative death or nonfatal MI within 30 days of surgery); these events occurred in 351 patients (7.0%) in the aspirin group and 355 (7.1%) in the placebo group, respectively, and 367 patients (7.3%) in the clonidine group and 339 (6.8%) in the placebo group, respectively. Aspirin increased the risk for major bleeding, which occurred in 230 patients (4.6%) versus 188 (3.8%) in the placebo group (HR, 1.23 [CI, 1.01 to 1.49]). Clonidine increased the risk for clinically significant hypotension, which occurred in 2385 patients (47.6%) versus 1854 (37.1%) in the placebo group (HR, 1.32 [CI, 1.24 to 1.40]). Cautions: The factorial study design has the benefit of permitting simultaneous testing of 2 different hypotheses, which can increase the efficiency of large-scale clinical trials. One of the strengths of this design is the ability to measure interaction between the 2 treatments. However, the investigators did not include an interaction plot to demonstrate any potential interaction between aspirin and clonidine if given together. Implications: In this study, neither aspirin nor clonidine administered perioperatively was found to reduce the risk for perioperative MI or death, but these agents did increase the risk for clinically significant side effects. Initiating therapy with either drug just before surgery should be done with caution and individualized to both the patient and surgery type, with increased vigilance for side effects.
Perioperative Pulmonary Medicine Preoperative Inspiratory Training Decreases Postoperative Pulmonary Complications Mans CM, Reeve JC, Elkins MR. Postoperative outcomes following preoperative inspiratory muscle training in patients undergoing cardiothoracic or upper abdominal surgery: a systematic review and meta-analysis. Clin Rehabil. 2014 Aug 26. [Epub ahead of print]. [PMID: 25160007]
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UPDATE Background: Patients who undergo open cardiothoracic or upper abdominal surgery are at increased risk for postoperative pulmonary complications. Preoperative inspiratory muscle training is thought to increase inspiratory muscle strength by applying a resistive load to the inspiratory muscles to achieve a training effect. This training can be achieved by isocapnic/normocapnic hyperpnea, inspiratory, resistive flow training or threshold pressure loading. This systematic review and meta-analysis was done to determine whether preoperative inspiratory muscle training reduces the incidence of postoperative pulmonary complications, decreases length of stay, and increases inspiratory muscle strength and endurance. Findings: Eight moderate-quality RCTs included 295 patients who underwent cardiac surgery (n = 180), thoracic surgery (n = 23), or upper abdominal surgery (n = 92). Compared with placebo, patients who received 2 to 4 weeks of inspiratory muscle training (one 15- to 30-minute session 6 or 7 days per week) had a significantly lower risk for postoperative pulmonary complications (RR, 0.48 [CI, 0.26 to 0.89]), a non–statistically significant decrease in hospital stay (mean difference, ⫺1.66 days [CI, ⫺3.64 to 0.31 days), and improved maximal inspiratory pressure (mean difference, 15 cm H2O [CI, 9 to 21 cm H2O]), which remained improved until 4 days postoperatively. Cautions: This meta-analysis combines outcomes from patients undergoing cardiac, thoracic, and open abdominal surgeries. Meta-analytic outcomes were not reported for NCS separately, so the benefit in this group may not be as robust. For the most important outcome, postoperative pulmonary complications, there were very few events overall (10 in the intervention group and 21 in the control group), which limits the strength of this evidence. Implications: Postoperative pulmonary complications are associated with increased health care costs; few interventions have been shown to significantly reduce the risk for these complications. If this relatively simple intervention can reduce postoperative pulmonary complications by half, it will have a substantial effect. A trial of preoperative inspiratory muscle training in patients before esophageal resection is currently under way (8) and will add to the available evidence.
Preoperative Diagnosis of Obstructive Sleep Apnea and Treatment With Continuous Positive Airway Pressure Are Associated With Reduced Risk for Postoperative Cardiovascular Complications Mutter TC, Chateau D, Moffatt M, et al. A matched cohort study of postoperative outcomes in obstructive sleep apnea: could preoperative diagnosis and treatment prevent complications? Anesthesiology. 2014;121:707-18. [PMID: 25247853] doi:10.1097/ALN.0000000000000407
Background: Obstructive sleep apnea (OSA) has been associated with increased postoperative cardiorespiratory complications, but evidence on whether treatment
Update in Perioperative Medicine
with continuous positive airway pressure (CPAP) improves perioperative outcomes is lacking. Findings: Using Canadian administrative data, researchers compared postoperative cardiovascular and respiratory outcomes in patients with preoperative undiagnosed OSA (n = 1571) and patients with preoperative diagnosed OSA who were prescribed CPAP (n = 2640) with outcomes in matched control patients without OSA (n = 16 777). Surgical procedures in patients with OSA were matched with up to 4 controls on surgical procedure, indication for procedure, and procedure date within 3 years. Multivariate analyses adjusted for baseline differences between the groups. Respiratory complications occurred in 0.79% of all surgeries in patients with OSA (undiagnosed and diagnosed combined) compared with 0.42% of control surgeries. In adjusted analyses, OSA (diagnosed and undiagnosed) was associated with respiratory complications (OR, 2.08 [CI, 1.35 to 2.19]), but diagnosed OSA with CPAP prescription was not associated with a significant reduction in risk compared with undiagnosed OSA. Cardiovascular complications occurred in 0.88% of all surgeries in patients with OSA versus 0.84% of matched control surgeries. In multivariate analysis, surgeries in patients with diagnosed OSA and CPAP prescription had significantly reduced risk for cardiovascular complications compared with surgeries in patients with undiagnosed OSA (OR, 0.34 [CI, 0.15 to 0.77]). Compared with matched controls, patients with diagnosed OSA had similar risk (OR, 0.75 [CI, 0.43 to 1.28]), whereas patients with undiagnosed OSA had increased risk for cardiovascular complications (OR, 2.20 [CI, 1.16 to 4.17]). For both respiratory and cardiovascular complications, increasing severity of OSA, age, comorbid disease, and type of surgery were important predictors of risk. Cautions: These observational data cannot confirm a causal relationship between surgical outcomes and OSA, but they suggest that CPAP may reduce postoperative cardiovascular complications. Administrative data did not enable identification of all important confounders or adherence to CPAP. Similarly, no information on anesthetic and analgesic care, type and intensity of postoperative monitoring, or body mass index was available. Implications: This study is the largest cohort study comparing postoperative outcomes in patients with undiagnosed and diagnosed OSA. It suggests that preoperative OSA diagnosis plus CPAP prescription is associated with lower postoperative cardiovascular complications compared with undiagnosed OSA. Of note, postoperative respiratory complications were twice as likely in patients with OSA overall compared with patients without OSA, but CPAP prescription was not associated with improved respiratory outcomes. Highquality trials are needed to determine whether preoperative OSA diagnosis plus CPAP treatment improves outcomes.
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Venous Thromboembolism Prophylaxis Combined Compression and Anticoagulation Is More Effective Than Either Modality Alone in Preventing Postoperative Deep Venous Thrombosis After Major Surgery Zareba P, Wu C, Agzarian J, et al. Meta-analysis of randomized trials comparing combined compression and anticoagulation with either modality alone for prevention of venous thromboembolism after surgery. Br J Surg. 2014;101:105362. [PMID: 24916118] doi:10.1002/bjs.9527
Background: The 2012 American College of Chest Physicians guidelines on antithrombotic therapy and prevention of thrombosis suggest combining compression and anticoagulation modalities for prevention of deep venous thrombosis (DVT) and pulmonary embolism (PE) in all patients undergoing major orthopedic surgery and in high-risk patients undergoing major abdominal or pelvic surgery (9, 10). However, it remains unclear whether the benefits of combination prophylaxis outweigh potential harms. Findings: This systematic review and meta-analysis compared combination DVT prophylaxis (compression and anticoagulation) with either modality alone for the prevention of postoperative DVT in patients undergoing major surgery. Eleven RCTs (4866 patients) compared combination prophylaxis with anticoagulation alone; 17 RCTs (4673 patients) compared combination prophylaxis with compression alone. Adding compression to anticoagulation decreased DVT (RR, 0.51 [CI, 0.36 to 0.73]); the effect did not differ on the basis of type of compression (stockings or intermittent pneumatic) or timing of compression initiation (before or after surgery). Adding compression to anticoagulation did not significantly reduce the risk for proximal DVT, symptomatic DVT, or mortality compared with anticoagulation alone, but it did reduce the risk for PE (RR, 0.43 [CI, 0.27 to 0.66]). Compared with anticoagulation alone, combination prophylaxis was associated with a significant reduction in DVT after abdominal and orthopedic surgeries. Adverse events associated with compression were not well-described. Adding anticoagulation to compression reduced the risk for DVT (RR, 0.56 [CI, 0.45 to 0.69]). Compared with compression alone, combination prophylaxis significantly decreased the risk for DVT in patients undergoing abdominal surgery, neurosurgery, and orthopedic surgery, regardless of surgery type, anticoagulant used, or timing of anticoagulation initiation. Combination prophylaxis also decreased the risk for proximal DVT compared with compression alone, but did not reduce the risk for symptomatic DVT or PE. Adding anticoagulation to compression increased bleeding (major or minor) (RR, 1.74 [CI, 1.29 to 2.34]); no significant increase in major bleeding was identified (RR, 1.73 [CI, 0.93 to 3.22]). Cautions: Studies of compression were of poor quality, and anticoagulation studies were of moderate quality. In addition, there was evidence of publication bias.
Implications: This analysis supports anticoagulants as the mainstay of DVT prophylaxis in patients undergoing major surgery unless bleeding risk is high, in which case compression alone is favored. Combined compression and anticoagulation is more effective than either modality alone in preventing postoperative DVT in high-risk patients. Addition of anticoagulation is associated with an increased risk for any, but not major, bleeding. Little evidence on adverse effects of compression is available.
Perioperative Medication Management Discontinuation of Angiotensin-Converting Enzyme Inhibitor and Angiotensin II Receptor Blocker Treatment Before Surgery May Be Safe in Certain Patients Twersky RS, Goel V, Narayan P, et al. The risk of hypertension after preoperative discontinuation of angiotensin-converting enzyme inhibitors or angiotensin receptor antagonists in ambulatory and same-day admission patients. Anesth Analg. 2014; 118:938-44. [PMID: 24681657] doi:10.1213/ANE.00000000 00000076
Background: Evidence-based consensus on the management of angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) in the perioperative period is lacking. The primary concern relates to refractory intraoperative and postoperative hypotension. However, hypertension and related adverse outcomes are a concern if treatment with ACE inhibitors and ARBs are discontinued. Findings: Ambulatory surgery patients receiving monitored anesthesia care, regional anesthesia, or general anesthesia were prospectively randomly assigned to discontinuation (n = 262) or continuation (n = 264) of ACE inhibitor and ARB therapy. The primary outcome was hypertension (defined by the Joint National Committee 7 classification) at the time of presentation for surgery. No significant differences were found between the 2 groups with regard to patient age (mean, 61.5 years), important comorbid conditions (diabetes, coronary artery disease, renal insufficiency, American Society of Anesthesiologists score), or preoperative systolic or mean blood pressure (132/78 mm Hg in the discontinuation group vs. 133/76 mm Hg in the continuation group). Preoperative stage 1 hypertension was present in 27.5% of the discontinuation group and 29.2% of the continuation group, and stage 2 hypertension was present in 9.9% and 8.3%, respectively (P = 0.775). No patients in either group had surgery cancelled owing to uncontrolled hypertension. Although maximum postoperative blood pressure was not available for all patients, no unplanned hospital admissions or adverse clinical outcomes occurred in either group. Too few patients in either group received treatment in a postanesthesia care unit for hypertension to examine differences in this secondary outcome.
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UPDATE Cautions: This study was conducted in patients undergoing ambulatory or same-day surgery, who may be healthier and undergoing lower-risk procedures than patients who are hospitalized after surgery. Patients with preoperative uncontrolled hypertension (>180 mm Hg systolic or >110 mm Hg diastolic) and those with a body mass index greater than 45 kg/m2 were ineligible for the study. Patients receiving diuretic therapy preoperatively continued to do so, which is often not the practice in inpatient settings. A small number of patients had stage 2 hypertension preoperatively; the study may have been underpowered to detect adverse events in this patient group. Implications: This RCT suggests that it is safe to discontinue ACE inhibitors and ARBs preoperatively in patients undergoing ambulatory or same-day surgery. However, until further evidence is available, it is prudent to customize perioperative management of ACE inhibitors and ARBs on the basis of patient characteristics and type of surgical procedure. From Mayo Clinic and Mayo Clinic College of Medicine, Rochester, Minnesota. Disclosures: Authors have disclosed no conflicts of interest. Forms can be viewed at www.acponline.org/authors/icmje/ ConflictOfInterestForms.do?msNum=M15-0206. Requests for Single Reprints: Karen F. Mauck, MD, MSc, Divi-
sion of General Internal Medicine, Department of Medicine, Mayo Clinic, 200 1st Street SW, Rochester, MN 55905; e-mail, [email protected]. Current Author Addresses: Drs. Mauck and Sundsted: Division of General Internal Medicine, Department of Medicine, Mayo Clinic, 200 1st Street SW, Rochester, MN 55905. Author Contributions: Conception and design: K.F. Mauck,
K.K. Sundsted. Analysis and interpretation of the data: K.K. Sundsted. Drafting of the article: K.F. Mauck, K.K. Sundsted. Critical revision of the article for important intellectual content: K.F. Mauck. Final approval of the article: K.F. Mauck, K.K. Sundsted.
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Update in Perioperative Medicine risk calculator: a decision aid and informed consent tool for patients and surgeons. J Am Coll Surg. 2013;217:833-42.e1-3. [PMID: 24055383] doi:10.1016/j.jamcollsurg.2013.07.385 2. Lee TH, Marcantonio ER, Mangione CM, Thomas EJ, Polanczyk CA, Cook EF, et al. Derivation and prospective validation of a simple index for prediction of cardiac risk of major noncardiac surgery. Circulation. 1999;100:1043-9. [PMID: 10477528] 3. Ford MK, Beattie WS, Wijeysundera DN. Systematic review: prediction of perioperative cardiac complications and mortality by the revised cardiac risk index. Ann Intern Med. 2010;152:26-35. [PMID: 20048269] doi:10.7326/0003-4819-152-1-201001050-00007 4. Fleisher LA, Fleischmann KE, Auerbach AD, Barnason SA, Beckman JA, Bozkurt B, et al. 2014 ACC/AHA guideline on perioperative cardiovascular evaluation and management of patients undergoing noncardiac surgery: a report of the American College of Cardiology/ American Heart Association Task Force on practice guidelines. J Am Coll Cardiol. 2014;64:e77-137. [PMID: 25091544] doi:10.1016/j .jacc.2014.07.944 5. Devereaux PJ, Yang H, Yusuf S, Guyatt G, Leslie K, Villar JC, et al; POISE Study Group. Effects of extended-release metoprolol succinate in patients undergoing non-cardiac surgery (POISE trial): a randomised controlled trial. Lancet. 2008;371:1839-47. [PMID: 18479744] doi:10.1016/S0140-6736(08)60601-7 6. Devereaux PJ, Xavier D, Pogue J, Guyatt G, Sigamani A, Garutti I, et al; POISE (PeriOperative ISchemic Evaluation) Investigators. Characteristics and short-term prognosis of perioperative myocardial infarction in patients undergoing noncardiac surgery: a cohort study. Ann Intern Med. 2011;154:523-8. [PMID: 21502650] doi:10.7326 /0003-4819-154-8-201104190-00003 7. Devereaux PJ, Sessler DI, Leslie K, Kurz A, Mrkobrada M, AlonsoCoello P, et al; POISE-2 Investigators. Clonidine in patients undergoing noncardiac surgery. N Engl J Med. 2014;370:1504-13. [PMID: 24679061] doi:10.1056/NEJMoa1401106 8. Valkenet K, Trappenburg JC, Gosselink R, Sosef MN, Willms J, Rosman C, et al. Preoperative inspiratory muscle training to prevent postoperative pulmonary complications in patients undergoing esophageal resection (PREPARE study): study protocol for a randomized controlled trial. Trials. 2014;15:144. [PMID: 24767575] doi: 10.1186/1745-6215-15-144 9. Falck-Ytter Y, Francis CW, Johanson NA, Curley C, Dahl OE, Schulman S, et al; American College of Chest Physicians. Prevention of VTE in orthopedic surgery patients: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. Chest. 2012;141:e278S-325S. [PMID: 22315265] doi:10.1378/chest.11 -2404 10. Gould MK, Garcia DA, Wren SM, Karanicolas PJ, Arcelus JI, Heit JA, et al; American College of Chest Physicians. Prevention of VTE in nonorthopedic surgical patients: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. Chest. 2012;141:e227S-77S. [PMID: 22315263] doi:10.1378/chest.11 -2297
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his summary highlights 9 key articles in perioperative medicine published in 2014. To identify these articles, we searched PubMed by using the keywords “perioperative or preoperative or postoperative or noncardiac surgery (NCS)” and limiting the search to a publication date of 2014, human study subjects, and English language. We then screened the 14 771 resulting abstracts. In addition, we used ACP JournalWise to identify high-quality, clinically relevant publications related to perioperative care. Fifty-six unique full-text articles were considered for inclusion. In selecting the 9 articles to highlight, we used the predetermined criteria of clinical relevance to internal medicine physicians, potential for practice change, and strength of the evidence. We gave priority to practice guidelines or meta-analyses that addressed clinical questions important to perioperative care. The selected represent topic areas ranging from perioperative cardiac and pulmonary medicine to venous thromboembolism prophylaxis and medication management.
Perioperative Cardiac Medicine Updated Guideline on Perioperative Cardiovascular Evaluation Fleisher LA, Fleischmann KE, Auerbach AD, et al. 2014 ACC/ AHA guideline on perioperative cardiovascular evaluation and management of patients undergoing noncardiac surgery: a report of the American College of Cardiology/American Heart Association Task Force on practice guidelines. J Am Coll Cardiol. 2014;64:e77-137. [PMID: 25091544] doi:10. 1016/j.jacc.2014.07.944
Background: The American College of Cardiology (ACC)/American Heart Association (AHA) guideline provides evidence- and expert opinion– based recommendations for preoperative risk assessment, cardiovascular testing, perioperative pharmacologic management, timing of surgery after percutaneous intervention, and perioperative monitoring of patients with (or at risk for) cardiovascular disease who undergo NCS. Findings: The guideline recommends an algorithmic approach to preoperative cardiac risk assessment to help determine whether cardiac stress testing is indicated. The suggested algorithm incorporates 1) surgical urgency, 2) presence of acute coronary syndromes, 3) combined clinical and surgery-specific risk for major adverse cardiac events (as determined by using the American College of Surgeons National Surgical Quality Improvement Program calculator [1] or the Revised
Cardiac Risk Index [RCRI] [2, 3]), and 4) functional capacity in metabolic equivalents. For non–low-risk surgical procedures, electrocardiography (ECG) is reasonable in patients with coronary or peripheral artery disease, arrhythmia, cerebrovascular disease, or structural heart disease, and preoperative assessment of left ventricular function is reasonable in patients with dyspnea or unstable heart failure symptoms. Coronary revascularization before NCS is recommended only if indicated outside of the surgical context and not exclusively to reduce perioperative risk. Optimal delays in surgery are 1 year after placement of a drug-eluting stent, 30 days after placement of a bare-metal stent, and 14 days after balloon angioplasty, to allow uninterrupted dual-antiplatelet therapy. Dual-antiplatelet therapy should be continued in patients undergoing urgent NCS during the first 4 to 6 weeks after placement of a bare-metal stent or drugeluting stent unless the risk for bleeding outweighs the risk for stent thrombosis. If dual-antiplatelet therapy is interrupted, use of aspirin should be continued and full therapy resumed as soon as possible after surgery. Patients who receive -blockers or statins on a long-term basis should continue to do so in the perioperative period. It may be reasonable to initiate treatment with -blockers in the perioperative period for patients with ischemia or more than 3 RCRI risk factors, but initiation should take place long enough in advance of surgery to assess safety and tolerability and should not occur on the day of surgery. It is reasonable to initiate statin therapy preoperatively in patients undergoing vascular surgery or a non–low-risk surgery who have at least 1 RCRI risk factor. Troponin measurement and ECG are recommended only for patients with signs or symptoms of cardiac ischemia. Cautions: Where randomized, controlled trial (RCT) evidence was unavailable, recommendations were based on observational data or expert opinion. Implications: Clinicians who provide perioperative care should familiarize themselves with this guideline.
Careful Patient Selection Is Needed When Considering Perioperative -Blockers Blessberger H, Kammler J, Domanovits H, et al. Perioperative beta-blockers for preventing surgery-related mortality and morbidity. Cochrane Database Syst Rev. 2014;9:CD004476. [PMID: 25233038] doi:10.1002/14651858.CD004476.pub2
Background: The 2014 ACC/AHA guidelines on perioperative cardiovascular evaluation and management added a Class III harm recommendation against starting -blockers on the day of surgery (4), and a more
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UPDATE conservative approach is recommended for initiation of -blocker therapy in high-risk patients. However, questions remain, including whether certain patients may benefit from perioperative -blockade. Findings: This systematic review of 89 RCTs (19 211 participants) analyzed cardiac surgery and NCS populations separately. In cardiac surgery (53 trials), there was no increase in 30-day all-cause mortality among patients taking -blockers versus those who were not (relative risk [RR], 0.73 [95% CI, 0.35 to 1.52]). In addition, no significant difference was found for many secondary outcomes in the cardiac surgery group, including acute myocardial infarction (MI) (RR, 1.04 [CI, 0.71 to 1.51]) and myocardial ischemia (RR, 0.51 [CI, 0.25 to 1.05]). -Blockers did significantly reduce the occurrence of ventricular and supraventricular tachycardias in cardiac surgery patients. In NCS (36 trials), -blockers potentially increased 30-day all-cause mortality (RR, 1.27 [CI, 1.01 to 1.59]) and cerebrovascular events (RR, 1.59 [CI, 0.93 to 2.71)], but they significantly reduced the occurrence of acute MI (RR, 0.73 [CI, 0.61 to 0.87]) and myocardial ischemia (RR, 0.43 [CI, 0.27 to 0.70]) while increasing the risk for bradycardia and hypotension. Cautions: Most of the results in this meta-analysis were driven by 1 large trial: POISE (PeriOperative ISchemic Evaluation) (5), which represented 71% of the weight of the meta-analysis. In the POISE trial, a generous dose of long-acting -blocker was administered 2 to 4 hours before surgery and postoperatively. Sensitivity analyses were conducted with and without the POISE trial results to account for this. Implications: This review highlights the continued need for careful patient selection and caution with regard to perioperative use of -blockers. There may be less risk and more potential benefit in cardiac surgery patients. There is also potential risk reduction with regard to perioperative acute MI and cardiac ischemia in NCS patients, but this must be carefully weighed against the possible increased risk for mortality, stroke, and hemodynamic instability. If -blocker therapy is started preoperatively, the meta-analysis highlights the importance of allowing enough time after initiation for dose titration and assessment of medication tolerance.
Postoperative Troponin Elevation Has Myocardial Injury Implications After NCS Botto F, Alonso-Coello P, Chan MT, et al; Vascular events In noncardiac Surgery patients cOhort evaluatioN (VISION) Writing Group. Myocardial injury after noncardiac surgery: a large, international, prospective cohort study establishing diagnostic criteria, characteristics, predictors, and 30-day outcomes. Anesthesiology. 2014;120:564-78. [PMID: 24534856] doi:10.1097/ALN.0000000000000113
Background: Whether troponin levels should be obtained postoperatively in the absence of ischemic symptoms presents a clinical conundrum. Data, including those from this study, have demonstrated an association between asymptomatic elevated troponin levels postoperatively and 30-day mortality (6). However, the
Update in Perioperative Medicine
2014 ACC/AHA guideline on perioperative cardiovascular evaluation recommends against routine postoperative troponin screening in unselected patients and cites uncertain benefit in high-risk patients without ischemic symptoms (4). This study sought to define diagnostic criteria, characteristics, predictors, and 30-day outcomes of myocardial injury after NCS (MINS). Findings: This international prospective cohort study included 15 065 participants aged 45 years or older who underwent NCS requiring at least overnight observation. Patients with elevated postoperative troponin T levels were assessed for ischemic ECG changes or ischemic symptoms. With a cutoff value for troponin T of 0.03 ng/mL or greater, 1200 patients (8%) met the criteria for MINS. The primary outcome was postoperative 30-day mortality; rates were 9.8% among patients with MINS compared with 1.1% among patients without MINS (odds ratio [OR], 10.07 [CI, 7.84 to 12.94]). Four perioperative complications (MINS, sepsis, stroke, and pulmonary embolism) were independent predictors of 30day mortality in multivariate analysis. Not unexpectedly, 87.1% of MINS events occurred within the first 2 days of surgery. Among patients who met the criteria for MINS, 84.2% did not experience ischemic symptoms and 58% did not fulfill the universal definition of MI. Patients with MINS were also at higher risk for nonfatal cardiac arrest, congestive heart failure, and stroke. Cautions: This study design is able to establish an association between mortality and other adverse events in patients with MINS, but it cannot definitively establish a causal relationship. It also does not tell us whether intervention when the troponin T level is elevated would improve outcomes. Implications: The results of this study suggest that regardless of ischemic features, postoperative elevation of the troponin T level is relatively common and has important prognostic implications. The significant number of patients with MINS (over one half of whom were completely asymptomatic) and the associated 10-fold increase in 30-day mortality calls into question the current practice of clinically dismissing minor elevations of the troponin T level in the postoperative period. We agree with the study investigators that additional clinical trials are needed to better define interventions to attenuate myocardial injury and perioperative mortality in patients with postoperative elevation of the troponin T level.
Guideline-Based Medical Management of Postoperative Elevated Troponin Levels Probably Improves Long-Term Outcomes Foucrier A, Rodseth R, Aissaoui M, et al. The long-term impact of early cardiovascular therapy intensification for postoperative troponin elevation after major vascular surgery. Anesth Analg. 2014;119:1053-63. [PMID: 24937347] doi:10.1213/ ANE.0000000000000302
Background: Postoperative elevation of the troponin level often occurs without symptoms or ECG changes suggestive of MI. Up to 65% of patients do not experi-
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ence ischemic symptoms with postoperative MI (6), and most cases go undiagnosed because current guidelines do not recommend routine postoperative surveillance with ECG and troponin measurement in asymptomatic patients (4). Although data suggest that routine monitoring of troponin levels in at-risk patients after surgery is needed to detect most MIs (which have an equally poor prognosis regardless of whether they are symptomatic or asymptomatic), whether early intervention in asymptomatic patients with elevated troponin levels will improve outcomes is uncertain. Findings: This case– control study identified 667 patients who underwent elective major vascular surgery. All patients had routine ECG and troponin I measurement on arrival to the postanesthetic care unit and on the first, second, and third postoperative days. Case patients (n = 66) were defined by an elevated troponin I level of 0.15 ng/mL or greater. Two control participants for each case patient were identified from the remaining patient pool (matched for RCRI score, age, sex, date, type of surgery, and presence of intraoperative complications). Case patients who had no modification of their cardiovascular treatment postoperatively (n = 23) were less likely to survive 1 year without experiencing a major cardiac event compared with the control group (hazard ratio [HR], 1.77 [CI, 1.13 to 2.42]). Case patients who did have therapeutic intensification (n = 43) were more likely to survive 1 year without experiencing a major cardiac event compared with the control group (HR, 0.63 [CI, 0.10 to 1.19]), but this finding was not statistically significant. Finally, patients with elevated troponin levels who did not receive treatment intensification were less likely to survive 1 year without experiencing a major cardiac event than were patients with elevated troponin levels who did receive treatment intensification (HR, 2.80 [CI, 1.05 to 24.20]). Cautions: This was a small observational study from a single institution involving only vascular surgery patients; generalizability to other types of surgery is limited. Elevation of the troponin level was the single criterion for case selection, with no discernment as to the cause of the elevation (cardiac or other). The study size did not allow for complete balance of preoperative risk factors among the groups despite propensity matching. Implications: Although no definite practice recommendations should be based on these observations, this is the first evidence to suggest that intensive treatment of a postoperative elevated troponin level with evidencebased medical management of acute coronary syndrome might improve long-term cardiac outcomes.
Neither Aspirin nor Clonidine Reduced the Risk for Death or Nonfatal MI in Patients Undergoing Noncardiac Surgery Devereaux PJ, Mrkobrada M, Sessler DI, et al; POISE-2 Investigators. Aspirin in patients undergoing noncardiac surgery. N Engl J Med. 2014;370:1494-503. [PMID: 24679062] doi: 10.1056/NEJMoa1401105
Background: Patients undergoing NCS may be at increased risk for perioperative complications, including MI, in part owing to platelet and sympathetic nervous system activation. Both aspirin and clonidine have been reported to decrease the risk for perioperative MI. However, substantial variability remains in the perioperative management of both medications, as well as concern about side effects. Findings: This RCT enrolled 10 010 patients using a 2 × 2 factorial design. Patients who had moderate or high risk for postoperative cardiac events were assigned to receive either 200 mg of aspirin or placebo 2 to 4 hours before surgery and 100 mg of aspirin or placebo daily up to 30 days after surgery; they were then assigned to receive either oral clonidine (0.2 mg) or placebo 2 to 4 hours before surgery and a clonidine patch (0.2 mg/d) or placebo patch that remained on for 72 hours postoperatively. The results for clonidine were reported in a separate article (7). The aspirin and clonidine groups did not differ with respect to the primary outcome (perioperative death or nonfatal MI within 30 days of surgery); these events occurred in 351 patients (7.0%) in the aspirin group and 355 (7.1%) in the placebo group, respectively, and 367 patients (7.3%) in the clonidine group and 339 (6.8%) in the placebo group, respectively. Aspirin increased the risk for major bleeding, which occurred in 230 patients (4.6%) versus 188 (3.8%) in the placebo group (HR, 1.23 [CI, 1.01 to 1.49]). Clonidine increased the risk for clinically significant hypotension, which occurred in 2385 patients (47.6%) versus 1854 (37.1%) in the placebo group (HR, 1.32 [CI, 1.24 to 1.40]). Cautions: The factorial study design has the benefit of permitting simultaneous testing of 2 different hypotheses, which can increase the efficiency of large-scale clinical trials. One of the strengths of this design is the ability to measure interaction between the 2 treatments. However, the investigators did not include an interaction plot to demonstrate any potential interaction between aspirin and clonidine if given together. Implications: In this study, neither aspirin nor clonidine administered perioperatively was found to reduce the risk for perioperative MI or death, but these agents did increase the risk for clinically significant side effects. Initiating therapy with either drug just before surgery should be done with caution and individualized to both the patient and surgery type, with increased vigilance for side effects.
Perioperative Pulmonary Medicine Preoperative Inspiratory Training Decreases Postoperative Pulmonary Complications Mans CM, Reeve JC, Elkins MR. Postoperative outcomes following preoperative inspiratory muscle training in patients undergoing cardiothoracic or upper abdominal surgery: a systematic review and meta-analysis. Clin Rehabil. 2014 Aug 26. [Epub ahead of print]. [PMID: 25160007]
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UPDATE Background: Patients who undergo open cardiothoracic or upper abdominal surgery are at increased risk for postoperative pulmonary complications. Preoperative inspiratory muscle training is thought to increase inspiratory muscle strength by applying a resistive load to the inspiratory muscles to achieve a training effect. This training can be achieved by isocapnic/normocapnic hyperpnea, inspiratory, resistive flow training or threshold pressure loading. This systematic review and meta-analysis was done to determine whether preoperative inspiratory muscle training reduces the incidence of postoperative pulmonary complications, decreases length of stay, and increases inspiratory muscle strength and endurance. Findings: Eight moderate-quality RCTs included 295 patients who underwent cardiac surgery (n = 180), thoracic surgery (n = 23), or upper abdominal surgery (n = 92). Compared with placebo, patients who received 2 to 4 weeks of inspiratory muscle training (one 15- to 30-minute session 6 or 7 days per week) had a significantly lower risk for postoperative pulmonary complications (RR, 0.48 [CI, 0.26 to 0.89]), a non–statistically significant decrease in hospital stay (mean difference, ⫺1.66 days [CI, ⫺3.64 to 0.31 days), and improved maximal inspiratory pressure (mean difference, 15 cm H2O [CI, 9 to 21 cm H2O]), which remained improved until 4 days postoperatively. Cautions: This meta-analysis combines outcomes from patients undergoing cardiac, thoracic, and open abdominal surgeries. Meta-analytic outcomes were not reported for NCS separately, so the benefit in this group may not be as robust. For the most important outcome, postoperative pulmonary complications, there were very few events overall (10 in the intervention group and 21 in the control group), which limits the strength of this evidence. Implications: Postoperative pulmonary complications are associated with increased health care costs; few interventions have been shown to significantly reduce the risk for these complications. If this relatively simple intervention can reduce postoperative pulmonary complications by half, it will have a substantial effect. A trial of preoperative inspiratory muscle training in patients before esophageal resection is currently under way (8) and will add to the available evidence.
Preoperative Diagnosis of Obstructive Sleep Apnea and Treatment With Continuous Positive Airway Pressure Are Associated With Reduced Risk for Postoperative Cardiovascular Complications Mutter TC, Chateau D, Moffatt M, et al. A matched cohort study of postoperative outcomes in obstructive sleep apnea: could preoperative diagnosis and treatment prevent complications? Anesthesiology. 2014;121:707-18. [PMID: 25247853] doi:10.1097/ALN.0000000000000407
Background: Obstructive sleep apnea (OSA) has been associated with increased postoperative cardiorespiratory complications, but evidence on whether treatment
Update in Perioperative Medicine
with continuous positive airway pressure (CPAP) improves perioperative outcomes is lacking. Findings: Using Canadian administrative data, researchers compared postoperative cardiovascular and respiratory outcomes in patients with preoperative undiagnosed OSA (n = 1571) and patients with preoperative diagnosed OSA who were prescribed CPAP (n = 2640) with outcomes in matched control patients without OSA (n = 16 777). Surgical procedures in patients with OSA were matched with up to 4 controls on surgical procedure, indication for procedure, and procedure date within 3 years. Multivariate analyses adjusted for baseline differences between the groups. Respiratory complications occurred in 0.79% of all surgeries in patients with OSA (undiagnosed and diagnosed combined) compared with 0.42% of control surgeries. In adjusted analyses, OSA (diagnosed and undiagnosed) was associated with respiratory complications (OR, 2.08 [CI, 1.35 to 2.19]), but diagnosed OSA with CPAP prescription was not associated with a significant reduction in risk compared with undiagnosed OSA. Cardiovascular complications occurred in 0.88% of all surgeries in patients with OSA versus 0.84% of matched control surgeries. In multivariate analysis, surgeries in patients with diagnosed OSA and CPAP prescription had significantly reduced risk for cardiovascular complications compared with surgeries in patients with undiagnosed OSA (OR, 0.34 [CI, 0.15 to 0.77]). Compared with matched controls, patients with diagnosed OSA had similar risk (OR, 0.75 [CI, 0.43 to 1.28]), whereas patients with undiagnosed OSA had increased risk for cardiovascular complications (OR, 2.20 [CI, 1.16 to 4.17]). For both respiratory and cardiovascular complications, increasing severity of OSA, age, comorbid disease, and type of surgery were important predictors of risk. Cautions: These observational data cannot confirm a causal relationship between surgical outcomes and OSA, but they suggest that CPAP may reduce postoperative cardiovascular complications. Administrative data did not enable identification of all important confounders or adherence to CPAP. Similarly, no information on anesthetic and analgesic care, type and intensity of postoperative monitoring, or body mass index was available. Implications: This study is the largest cohort study comparing postoperative outcomes in patients with undiagnosed and diagnosed OSA. It suggests that preoperative OSA diagnosis plus CPAP prescription is associated with lower postoperative cardiovascular complications compared with undiagnosed OSA. Of note, postoperative respiratory complications were twice as likely in patients with OSA overall compared with patients without OSA, but CPAP prescription was not associated with improved respiratory outcomes. Highquality trials are needed to determine whether preoperative OSA diagnosis plus CPAP treatment improves outcomes.
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Venous Thromboembolism Prophylaxis Combined Compression and Anticoagulation Is More Effective Than Either Modality Alone in Preventing Postoperative Deep Venous Thrombosis After Major Surgery Zareba P, Wu C, Agzarian J, et al. Meta-analysis of randomized trials comparing combined compression and anticoagulation with either modality alone for prevention of venous thromboembolism after surgery. Br J Surg. 2014;101:105362. [PMID: 24916118] doi:10.1002/bjs.9527
Background: The 2012 American College of Chest Physicians guidelines on antithrombotic therapy and prevention of thrombosis suggest combining compression and anticoagulation modalities for prevention of deep venous thrombosis (DVT) and pulmonary embolism (PE) in all patients undergoing major orthopedic surgery and in high-risk patients undergoing major abdominal or pelvic surgery (9, 10). However, it remains unclear whether the benefits of combination prophylaxis outweigh potential harms. Findings: This systematic review and meta-analysis compared combination DVT prophylaxis (compression and anticoagulation) with either modality alone for the prevention of postoperative DVT in patients undergoing major surgery. Eleven RCTs (4866 patients) compared combination prophylaxis with anticoagulation alone; 17 RCTs (4673 patients) compared combination prophylaxis with compression alone. Adding compression to anticoagulation decreased DVT (RR, 0.51 [CI, 0.36 to 0.73]); the effect did not differ on the basis of type of compression (stockings or intermittent pneumatic) or timing of compression initiation (before or after surgery). Adding compression to anticoagulation did not significantly reduce the risk for proximal DVT, symptomatic DVT, or mortality compared with anticoagulation alone, but it did reduce the risk for PE (RR, 0.43 [CI, 0.27 to 0.66]). Compared with anticoagulation alone, combination prophylaxis was associated with a significant reduction in DVT after abdominal and orthopedic surgeries. Adverse events associated with compression were not well-described. Adding anticoagulation to compression reduced the risk for DVT (RR, 0.56 [CI, 0.45 to 0.69]). Compared with compression alone, combination prophylaxis significantly decreased the risk for DVT in patients undergoing abdominal surgery, neurosurgery, and orthopedic surgery, regardless of surgery type, anticoagulant used, or timing of anticoagulation initiation. Combination prophylaxis also decreased the risk for proximal DVT compared with compression alone, but did not reduce the risk for symptomatic DVT or PE. Adding anticoagulation to compression increased bleeding (major or minor) (RR, 1.74 [CI, 1.29 to 2.34]); no significant increase in major bleeding was identified (RR, 1.73 [CI, 0.93 to 3.22]). Cautions: Studies of compression were of poor quality, and anticoagulation studies were of moderate quality. In addition, there was evidence of publication bias.
Implications: This analysis supports anticoagulants as the mainstay of DVT prophylaxis in patients undergoing major surgery unless bleeding risk is high, in which case compression alone is favored. Combined compression and anticoagulation is more effective than either modality alone in preventing postoperative DVT in high-risk patients. Addition of anticoagulation is associated with an increased risk for any, but not major, bleeding. Little evidence on adverse effects of compression is available.
Perioperative Medication Management Discontinuation of Angiotensin-Converting Enzyme Inhibitor and Angiotensin II Receptor Blocker Treatment Before Surgery May Be Safe in Certain Patients Twersky RS, Goel V, Narayan P, et al. The risk of hypertension after preoperative discontinuation of angiotensin-converting enzyme inhibitors or angiotensin receptor antagonists in ambulatory and same-day admission patients. Anesth Analg. 2014; 118:938-44. [PMID: 24681657] doi:10.1213/ANE.00000000 00000076
Background: Evidence-based consensus on the management of angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) in the perioperative period is lacking. The primary concern relates to refractory intraoperative and postoperative hypotension. However, hypertension and related adverse outcomes are a concern if treatment with ACE inhibitors and ARBs are discontinued. Findings: Ambulatory surgery patients receiving monitored anesthesia care, regional anesthesia, or general anesthesia were prospectively randomly assigned to discontinuation (n = 262) or continuation (n = 264) of ACE inhibitor and ARB therapy. The primary outcome was hypertension (defined by the Joint National Committee 7 classification) at the time of presentation for surgery. No significant differences were found between the 2 groups with regard to patient age (mean, 61.5 years), important comorbid conditions (diabetes, coronary artery disease, renal insufficiency, American Society of Anesthesiologists score), or preoperative systolic or mean blood pressure (132/78 mm Hg in the discontinuation group vs. 133/76 mm Hg in the continuation group). Preoperative stage 1 hypertension was present in 27.5% of the discontinuation group and 29.2% of the continuation group, and stage 2 hypertension was present in 9.9% and 8.3%, respectively (P = 0.775). No patients in either group had surgery cancelled owing to uncontrolled hypertension. Although maximum postoperative blood pressure was not available for all patients, no unplanned hospital admissions or adverse clinical outcomes occurred in either group. Too few patients in either group received treatment in a postanesthesia care unit for hypertension to examine differences in this secondary outcome.
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UPDATE Cautions: This study was conducted in patients undergoing ambulatory or same-day surgery, who may be healthier and undergoing lower-risk procedures than patients who are hospitalized after surgery. Patients with preoperative uncontrolled hypertension (>180 mm Hg systolic or >110 mm Hg diastolic) and those with a body mass index greater than 45 kg/m2 were ineligible for the study. Patients receiving diuretic therapy preoperatively continued to do so, which is often not the practice in inpatient settings. A small number of patients had stage 2 hypertension preoperatively; the study may have been underpowered to detect adverse events in this patient group. Implications: This RCT suggests that it is safe to discontinue ACE inhibitors and ARBs preoperatively in patients undergoing ambulatory or same-day surgery. However, until further evidence is available, it is prudent to customize perioperative management of ACE inhibitors and ARBs on the basis of patient characteristics and type of surgical procedure. From Mayo Clinic and Mayo Clinic College of Medicine, Rochester, Minnesota. Disclosures: Authors have disclosed no conflicts of interest. Forms can be viewed at www.acponline.org/authors/icmje/ ConflictOfInterestForms.do?msNum=M15-0206. Requests for Single Reprints: Karen F. Mauck, MD, MSc, Divi-
sion of General Internal Medicine, Department of Medicine, Mayo Clinic, 200 1st Street SW, Rochester, MN 55905; e-mail, [email protected]. Current Author Addresses: Drs. Mauck and Sundsted: Division of General Internal Medicine, Department of Medicine, Mayo Clinic, 200 1st Street SW, Rochester, MN 55905. Author Contributions: Conception and design: K.F. Mauck,
K.K. Sundsted. Analysis and interpretation of the data: K.K. Sundsted. Drafting of the article: K.F. Mauck, K.K. Sundsted. Critical revision of the article for important intellectual content: K.F. Mauck. Final approval of the article: K.F. Mauck, K.K. Sundsted.
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