Disease-a-Month 60 (2014) 402–411
Contents lists available at ScienceDirect
Disease-a-Month journal homepage: www.elsevier.com/locate/disamonth
Clinical pearls in perioperative medicine Margaret Beliveau, MD, John B. Bundrick, MD
Case 1 A 40-year-old woman with type 2 diabetes will undergo a laparoscopic cholecystectomy for symptomatic biliary colic. She has a history of severe postoperative nausea and vomiting after a cesarian section. Recently, her blood sugars have been poorly controlled. She is a non-smoker and does not use alcohol. She also has a history of hypertension, which is well controlled. Physical exam reveals a positive Murphy’s sign. Preoperative laboratory evaluation reveals normal creatinine, CBC, and electrolytes. Hemoglobin A1C is 9.0%. ECG shows heart rate of 72 and normal sinus rhythm, with a QTc of 0.46 s. The patient is very anxious about the possibility of another episode of severe postoperative nausea and vomiting. What is the best way to prevent postoperative nausea and vomiting in this patient? A. B. C. D. E.
Ondansetron 4 mg IV given at the end of surgery Dexamethasone 4 mg IV, given at induction Dronabinol 2.5 mg orally, given before induction Droperidol 1.25 mg IV, given at the end of surgery Metoclopramide 50 mg IV, given at the end of surgery.
Discussion Postoperative nausea and vomiting (PONV) can be seen in 30–50% of patients undergoing surgical procedures. Risk factors include female gender, non-smokers, history of postoperative nausea and vomiting or motion sickness, and use of postoperative opioids. Younger age ( o50 years) is also associated with an increased risk of PONV. Having 4/4 risk factors, as this patient does, is associated with an 80% risk of PONV. This patient also has a slightly increased QTc (normal o 0.45 s in women). A recent study demonstrated that perioperative doses of ondansetron did not lengthen the QT interval. This patient is diabetic, so dexamethasone, while effective, might worsen her blood sugar control, which is already not optimal. Cannabinoids have no role in the prevention of perioperative http://dx.doi.org/10.1016/j.disamonth.2014.04.018 0011-5029/& 2014 Mosby, Inc. All rights reserved.
M. Beliveau, J.B. Bundrick / Disease-a-Month 60 (2014) 402–411
403
nausea and vomiting. There is currently an FDA black box warning about the use of droperidol, although studies have demonstrated that the risk of QTC interval prolongation at lower doses is probably acceptable. Metoclopramide is not effective in preventing postoperative nausea and vomiting. It also may cause extrapyramidal side effects. Clinical pearl Ondansetron given at lower doses used for prophylaxis of PONV does not significantly prolong the QTC interval. References 1. Obal D, Yang D, Sessler D. Perioperative doses of ondansetron or dolasetron do not lengthen the QT interval. Mayo Clin Proc. 2014;89(1):69–80. 2. Apfel CC, Hiedrich FM, Jukar-Rao L, Hornuss C, Whalen RP, Zhang K, Cakmakkaya OS. Evidence-based analysis of risk factors for postoperative nausea and vomiting. Br J Anaesth. 2012(9):742–53.
Case 2 A 26-year-old man with sickle cell disease (Hg SS) is being seen for a preoperative medical evaluation. He is scheduled to undergo a right total hip arthroplasty because of avascular necrosis of the femoral head. He has a history of frequent pain crises. He is currently managed with hydroxyurea. He has recently been tested negative for HIV and Hepatitis B and C. He has received blood transfusions in the past and has had a history of an acute transfusion reaction 5 years ago. His baseline hemoglobin is 7.5 g/dL. What is the most appropriate recommendation for management in the perioperative setting? A. B. C. D. E.
Exchange transfusion to decrease the Hgb S level to o30% “Top-up” transfusion to increase the hemoglobin to 10.0 g/dL No transfusion preoperatively, transfuse only for postoperative complications “Top-up” transfusion to increase the hemoglobin to 4 12.0 g/dL Vigorous IV hydration for 6 h preoperatively
Discussion Patients with sickle cell disease are at risk for many postoperative complications. These patients are now living longer with their disease and are requiring surgical procedures for a variety of problems. Some of the most commonly performed procedures include cholecystectomy, ENT surgery, and orthopedic procedures for avascular necrosis of the femoral head. Preoperative transfusion can improve outcomes, especially for patients undergoing intermediate-risk procedures such as total hip arthroplasty. A large study published in 1995 did not demonstrate any benefit to exchange transfusion compared with “top-up” transfusion. However, this study did not include a cohort receiving no transfusion. The recent TAPS study demonstrated that preoperative transfusion decreased the risk of serious adverse events and postoperative complications. The most serious complication in patients who did not receive transfusions preoperatively was acute chest syndrome. Transfusion was aimed at increasing the hemoglobin to 10 g/dL or, in some cases, to achieve a hemoglobin S of less than 60%. Only one of the [#] patients in the transfusion group developed alloimmunization at 3 months.
404
M. Beliveau, J.B. Bundrick / Disease-a-Month 60 (2014) 402–411
Measures that help decrease the risk of complications in patients with sickle cell disease include vigorous hydration until the patient is able to take fluids by mouth, maintaining the oxygen saturation at greater than 96% and appropriate DVT prophylaxis. Clinical pearl “Top-up” transfusion to achieve hemoglobin of 10 g/dL will decrease the risk of sickle cellrelated perioperative complications. References 1. Howard J, Malfroy M, Choo L, et al. The transfusion alternatives preoperatively in sickle cell disease (TAPS) study: a randomized, controlled, multicentre clinical study. Lancet. 2013;381: 930–38. 2. Vichinsky EP, Haberkarn CM, Neumayr L, et al. A comparison of conservative and aggressive transfusion regimen in the perioperative management of sickle cell disease. The Preoperative Transfusion in Sickle Cell Disease Study Group. N Engl J Med. 1995;333:206–213. Case 3 A 40-year-old woman is being evaluated preoperatively. She has recently been found to have ovarian cancer and is scheduled for an exploratory laparotomy for staging and cytoreduction. She is obese, with a BMI of 37. She has a history of diet-controlled diabetes and obstructive sleep apnea, for which she uses CPAP. Her hemoglobin A1C is 7.5%. On physical exam, her blood pressure is 125/80. Her heart rate is 76. Heart and lung exams are normal. She does have trace pitting edema in her lower extremities, which she notes becomes worse as the day progresses. She has a normal ECG and chest X-ray. Her creatinine is normal. Her platelet count is 250,000. What is the most appropriate strategy for perioperative venous thromboembolism (VTE) prophylaxis in this patient? A. Rivaroxaban 20 mg once daily for 10 days after surgery B. Warfarin, adjusted to maintain an INR of 2.0–3.0, starting the day of surgery and continued for 14 days C. Mechanical compression with pneumatic compression sleeves, placed before surgery and continued until the patient is ambulatory D. Unfractionated heparin (UFH) 5000 units SQ twice daily until hospital discharge E. Low-molecular-weight heparin (LMWH) in prophylactic doses for 4 weeks postoperatively Discussion Patients with active malignancy are at an increased risk for perioperative VTE. Recent guidelines from the American Society of Clinical Oncology recommend that all patients with malignancy undergoing major surgical procedures receive appropriate pharmacologic prophylaxis, unless the patient has a contraindication such as a high bleeding risk. LMWH or UFH is recommended. The new oral anticoagulants, such as rivaroxaban, are not recommended in this situation. Warfarin is not recommended. Mechanical prophylaxis may provide increased protection when added to pharmacologic methods but are not sufficient when used alone. In patients undergoing major abdominal or pelvic surgery for cancer, who have other VTE risk factors (such as obesity, history of VTE, medical comorbidities, or restricted mobility), prophylaxis should be extended up to 4 weeks postoperatively.
M. Beliveau, J.B. Bundrick / Disease-a-Month 60 (2014) 402–411
405
Clinical pearl Patients with active malignancy undergoing major surgical procedures require extended pharmacologic prophylaxis with either LMWH or UFH. References 1. Lyman GH, Khorana AA, Kuderer NM, et al. Venous thromboembolism prophylaxis and treatment in patients with cancer: American society of Clinical Oncology Clinical Practice Guideline Update. J Clin Oncol. 2013;31:2189–2204. Case 4 A 98-year-old woman falls in her nursing home while ambulating with her walker. She sustains a right humerus and a right femoral neck fracture. The humeral fracture can be managed non-operatively. The orthopedist recommends surgical repair of the femoral fracture. The patient has a history of congestive heart failure, with grade 2/4 diastolic dysfunction. She also has a history of severe aortic stenosis but has refused surgery in the past. She has moderate dementia and chronic renal insufficiency. She also has history of atrial fibrillation. In the past, her heart rate has dropped into the 20s when beta blockers were given. Current medications include lisinopril, furosemide, and Celexa. A review of systems is obtained from her family. They deny any history of dyspnea with exertion. She has no history of chest pain. She has no history of syncope and is able to ambulate with her walker. On exam, her heart rate is 61 and is irregular. Her blood pressure is 130/80. She has a 3/6 latepeaking systolic murmur. Her lungs are clear. She has no edema. Laboratory evaluation shows hemoglobin of 10, MCV of 106, and creatinine of 1.7, all of which are unchanged from a year prior. Her ECG shows atrial fibrillation, with a prolonged QTC and left anterior fascicular block. The patient has told her family in the past that she does not want to live if she cannot be ambulatory. She currently has a DNR order in place. Which of the following is true regarding the DNR order? A. The DNR order must be rescinded before the patient goes to the OR B. She (or her surrogates) are more likely to refuse surgery because she has a pre-existing DNR order C. If the patient refuses to rescind the DNR order, the surgeon has the right to refuse to operate on her D. Her risk of death is no different than a patient who does not have a pre-existing DNR order E. It is acceptable for her to delegate decisions about perioperative resuscitation to her care team Patients have a right to self-determination, and this is the supreme standard in medical ethics. The American Society of Anesthesiologists, and other professional organizations, has long stated that automatic suspension of a DNR order for surgery will violate the patient’s right to self-determination. Studies have shown that patients with DNR orders will consent to surgery if the surgery will help in the palliation of pain or in the maintenance of quality of life. Patients are also willing to accept “aggressive” interventions for conditions that are not immediately related to their primary medical illnesses. Scarborough and Pappas showed that DNR patients having emergency surgery have a higher risk of death within 30 days. The DNR order has been shown to be an independent predictor of postoperative mortality in patients undergoing emergency surgery. This appears to be primarily related to the development of postoperative complications. While patients with DNR orders have a similar rate of postoperative complications when compared to patients who do not have
406
M. Beliveau, J.B. Bundrick / Disease-a-Month 60 (2014) 402–411
DNR orders, patients with DNR orders are more likely to die as a result of these complications. This appears to be due to decreased willingness to aggressively treat major complications. Most patients expect that there would be a detailed discussion with their care team regarding their goals of care and personal values. It is acceptable for patients to delegate perioperative decisions regarding appropriate intervention to the anesthesiologist or surgeons, once the context of the patient’s stated goals and values has been considered. Clinical pearl DNR orders help identify a patient’s goals and values. They should not be automatically rescinded in the OR. A detailed discussion regarding a patient’s goals of care is critical prior to a surgical procedure. References 1. Burkle CM, Swetz KM, Armstrong MH, Keegan MT. Patient and doctor attitudes and beliefs concerning perioperative do not resuscitate orders: anesthesiologists’ growing compliance with patient autonomy and self determination guidelines. BMC Anesthesiol. 2013;13:2. 2. Scarborough JE, Pappas TN. The effect of do-not-resuscitate status on postoperative mortality in the elderly following emergency surgery. AdvSurg. 2013;47:213–225. 3. Scott TH, Gavin JR. Palliative surgery in the do-not-resuscitate patient: ethical and practical suggestions for management. Anesthesiol Clin. 2012;30:1–12. Case 5 A 78-year-old man has a history of recurrent bladder cancer. He has undergone radiation therapy and chemotherapy and failed both of these. He has developed persistent hematuria and is now transfusion dependent. He is being seen for preoperative evaluation prior to a planned curative cystectomy. Eight months ago, he complained of fatigue and exertional chest discomfort despite having normal hemoglobin. He was found to have an abnormal ECG and ultimately underwent cardiac catheterization. He had two drug-eluting stents placed, in the left anterior descending and right coronary arteries. The patient has since been asymptomatic. Adenosine–sestamibi test performed in anticipation of his surgery was positive for a small area of reversible inferior ischemia. He was evaluated by his cardiologist, who felt that the benefit of the surgical procedure outweighed the cardiac risk. He was thought to be medically optimized. Current medications include aspirin 81 mg daily and clopidogrel 75 mg daily. His medications also include metoprolol, lisinopril, and atorvastatin. His functional status is less than 4 mets. His resting pulse rate is 60. What recommendations should you make regarding his dual antiplatelet therapy? A. The patient should undergo the surgical procedure on aspirin and clopidogrel. B. The administration of aspirin should be stopped, but the administration of clopidogrel should be continued. C. The administration of aspirin and clopidogrel can be interrupted for the surgical procedure. D. The administration of clopidogrel can be stopped, but the administration of aspirin should be continued. E. The administration of aspirin and clopidogrel should be discontinued and the patient should be bridged with low-molecular-weight heparin.
M. Beliveau, J.B. Bundrick / Disease-a-Month 60 (2014) 402–411
407
Discussion In the United States, as many as 900,000 patients receive coronary stents annually. The majority of these are drug-eluting stents. Up to 5% of patients with recently implanted stents will require surgery within a year of stent placement. The major risk factor for stent thrombosis is premature discontinuation of dual antiplatelet therapy. The mortality rate from stent thrombosis is as much as 40–50%. Current guidelines recommend that dual antiplatelet therapy be continued for a period of 12 months after the placement of drug-eluting stents. Most current guidelines recommend continuing antiplatelet therapy in the perioperative setting, unless there is a high bleeding risk. Additional recommendations include delaying elective surgery until a year after stent placement. There is considerable controversy about management of patients who require nonelective surgery after stent placement. A recent large study of patients undergoing noncardiac surgery within 2 years of stent placement showed that major adverse cardiac events were associated with emergency surgery and a Revised Cardiac Risk Index (RCRI) of 42. Timing of surgery, beyond 6 months after stent implantation, was not significantly associated with major adverse cardiac events. Management of dual antiplatelet therapy should be individualized, based on the bleeding risk of the surgery, as well as the patient’s risk of thrombosis. High risk of stent thrombosis can be seen in patients with long stents, in multiple or overlapping stents, in stents at bifurcations, and in patients with recent acute coronary syndrome, prior history of stent thrombosis, chronic kidney disease, and diabetes. While the procedure for this patient may be associated with an increased risk of bleeding, most guidelines would advise that continuation of aspirin would be recommended for prevention of stent thrombosis. There is no role for bridging with lowmolecular-weight heparin. Clinical pearl Management of dual antiplatelet therapy in patients with cardiac stents who require noncardiac surgery remains unclear. New data indicates that after 6 months, patients with low risk of stent thrombosis may be managed with aspirin alone in the perioperative setting. References 1. Hawn MT, Graham LA, Richmond JS, et al. Risk of major adverse cardiac events following noncardiac surgery in patients with coronary stents. J Am Med Assoc. 2013;310(14):1462– 1472. 2. Capodanno D, Angiolillo DJ. Management of antiplatelet therapy in patients with coronary artery disease requiring cardiac and noncardiac surgery. Circulation. 2013;128:2785–2798. 3. Darvish-Kazem S, Gandhi M, Marcucci M, Douketis JD. Perioperative management of antiplatelet therapy in patients with coronary stent who need noncardiac surgery. Chest. 2013;144(6):1848–1856. 4. Hawn MT, Graham LA, Richman JR, et al. The Incidence and timing of noncardiac surgery after cardiac stent implantation. J Am Coll Surg. 2012;214:658–657. Case 6 A 60-year-old man is being evaluated preoperatively in anticipation of robotic prostatectomy for a Gleason 3 þ 3 prostate adenocarcinoma. He was initially managed with hormonal therapy. However, the patient preferred to have a prostatectomy performed. His past medical history is significant for morbid obesity, with a body mass index of 44. He has no history of hypertension, coronary artery disease, pulmonary disease, kidney disease, or hyperlipidemia. He was noted to have impaired fasting blood sugar, with a fasting blood sugar of 118. He is a construction worker and is quite physically active. He denies any shortness of breath or chest discomfort. He is a never-smoker.
408
M. Beliveau, J.B. Bundrick / Disease-a-Month 60 (2014) 402–411
On physical exam, his weight is 134.6 kg, with a height of 173.6 cm. Waist circumference is 134 cm. Neck circumference is 42 cm. The patient notes that his wife now sleeps in a different room, because of his snoring. He also notes that if he sits down to watch television or read, he will often fall asleep. He has fallen asleep while driving once. Laboratory evaluation reveals hemoglobin of 15.6. Fasting blood sugar is 118. His electrolytes are normal. His creatinine is normal at 1.0. ECG shows normal sinus rhythm with first-degree AV block. Surgical procedure is planned for tomorrow. What do you recommend to the surgeon? A. The patient is medically optimized for surgery, and nothing further needs to be done. B. The patient is at high risk for OSA. Surgery should be postponed until a polysomnogram can be performed. C. The patient should be screened with the STOP-BANG questionnaire. If his score is suggestive of OSA, surgery should be postponed until a polysomnogram can be performed. D. The patient should be presumed to have OSA and should be monitored for respiratory events in the PACU. If respiratory events occur, he should be monitored for 24–48 h postoperatively. E. The patient is at high risk for OSA and should not receive opioids postoperatively. Discussion Obstructive sleep apnea (OSA) has been associated with numerous perioperative complications, including hypoxemia, cardiac arrhythmias, myocardial ischemia, reintubation, unexpected ICU admission, and sudden death. These patients often have multiple medical comorbidities, which put them at an increased risk. Many anesthetic agents promote airway collapse and respiratory depression. In addition, these patients often require postoperative opioids, and this further increases the risk of respiratory suppression. Many patients are suspected to have OSA when they undergo preoperative evaluation. There are multiple instruments available to screen for OSA. The STOP-BANG questionnaire is quite useful in identifying patients at higher risk. The acronym designates eight symptoms and signs associated with OSA, and a score of three or greater indicates a high probability of OSA. An optimal management strategy for patients with suspected obstructive sleep apnea who are undergoing surgery has not been clearly defined. There is no clear evidence that a polysomnogram and preoperative positive airway pressure will improve surgical outcomes. The optimal time for treating the patients with PAP preoperatively is unknown. The Society for Ambulatory Anesthesia recommends that if a patient is suspected to have OSA, the surgical team should proceed under the assumption that the patient in fact does have OSA. Gali et al. have demonstrated that the Respiratory-Specific Assessment in the PostAnesthesia Care Unit (PACU) can be used to identify patients at an increased risk of postoperative complications of OSA. These patients should be monitored remotely for desaturation in the postoperative setting, especially if the use of opioids for pain management is anticipated. It is not reasonable to simply withhold opioids in a patient who would otherwise require them. Clinical pearl Patients who are identified preoperatively as being at a high risk for OSA should be monitored in the PACU for respiratory events. Patients with evidence of respiratory events in the PACU should be admitted to a monitored unit. References 1. Gali B, Whalen FX, Schroeder DR et al. Identification of patients at risk for postoperative respiratory complications using a preoperative obstructive screening tool and postanesthesia care assessment. Anesthesiology. 2009;110:869–877.
M. Beliveau, J.B. Bundrick / Disease-a-Month 60 (2014) 402–411
409
2. Weingarten TN, Kor BJ, Gali B, Sprung J. Predicting postoperative pulmonary complications in high risk populations. Curr Opin Anesthiol. 2013;26:116–125. 3. Joshi GP, Ankichetty SP, Gan TJ, Chung F. Society for Ambulatory Anesthesia consensus statement on preoperative selection of adult patients with obstructive sleep apnea scheduled for ambulatory surgery. Anesth Analg. 2012;115:1060–1068. 4. Adesanya AO, Grelich NB, Joshi GP. Perioperative management of obstructive sleep apnea. Chest. 2010;138(6):1489–1498. 5. Auckley D, Bolden N. Preoperative screening and perioperative care of the patient with sleepdisordered breathing. Curr Opin Pulm Med. 2012;18:588–595. Case 7 A 75-year-old man is scheduled for a right hemicolectomy. He has a history of atrial fibrillation. He has no history of stroke. He does have hypertension, which is well controlled on metoprolol. He is not diabetic. His last echocardiogram showed a dilated left atrium. He is currently on dabigatran 150 mg twice daily. His creatinine clearance is 62 mL/min. He has a history of gastroesophageal reflux, currently treated with omeprazole 20 mg daily. He has an excellent functional status. On physical examination, his blood pressure is 130/85, with a heart rate of 62. His heart rhythm is irregular. His lungs are clear. He has no edema. Routine DVT prophylaxis with low-molecular-weight heparin is planned postoperatively. What do you recommend regarding the dabigatran? A. Dabigatran should be discontinued 5 days before the planned surgical procedure. B. Dabigatran should be discontinued 5 days before the planned surgical procedure and lowmolecular-weight heparin should be started 3 days before the procedure. C. Dabigatran should be discontinued 3 days before the planned surgical procedure, check prothrombin time preoperatively D. Dabigatran should be discontinued 3 days before the planned surgical procedure E. If the patient develops a postoperative ileus, therapeutic doses of low-molecular-weight heparin should be given until bowel function returns. Discussion The perioperative management of oral anticoagulants is determined by a number of clinical issues. Dabigatran is a direct thrombin inhibitor. It is not highly protein bound. Unlike vitamin K antagonists, it does not require routine coagulation monitoring. It has been approved for stroke prevention in patients with nonvalvular atrial fibrillation. Because it is cleared by the kidney, it is contraindicated if the creatinine clearance is less than 30 mL/min. The timing of preoperative discontinuation is determined by the creatinine clearance and the bleeding risk of the procedure. In a patient with a creatinine clearance of 50–80 mL/min, dabigatran can be discontinued one day prior to the planned surgical procedure if it is a low bleeding risk procedure. For high bleeding risk procedures, the current recommendation is discontinuing this drug 2–4 days preoperatively. There is no need to hold the medication for more than 2–4 days. This is a high bleeding risk procedure, so a recommendation of discontinuing dabigatran 2–3 days in advance would be appropriate. While dabigatran does slightly prolong the prothrombin time in a dose-dependent manner, this lab test is insensitive for measuring the antithrombotic effect of the drug and is not recommended. This patient has a CHADS-2 score of two. He would be considered low risk for a thromboembolism. Therefore, he does not require any bridging therapy preoperatively. In situations where the absorption of dabigatran would be impaired, for example, postoperative ileus, the drug should be held until the return of bowel function. While this patient does need DVT prophylaxis, if he should develop an ileus, there would be no need for therapeutic doses of low-molecular-weight heparin.
410
M. Beliveau, J.B. Bundrick / Disease-a-Month 60 (2014) 402–411
Clinical pearl In patients with normal renal function, dabigatran can be discontinued 1 day preoperatively for low bleeding risk procedures and 2–4 days preoperatively for high bleeding risk procedures. References 1. Levy JH, Faraoni D, Spring JL, Douketis JD, Samama CM. Managing new oral anticoagulants in the perioperative and intensive care unit setting. Anesthesiology. 2013;118:1466–1474. 2. Spyropoulos AC, Douketis JD. How I treat anticoagulated patients undergoing an elective procedure or surgery. Blood. 2012;120:2954–2962. 3. Douketis JD, Spyropoulos AC, Spencer FA, et al. Perioperaitve management of antithrombotic therapy: antithrombotic therapy and prevention of thrombosis, 9th ed.: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. Chest. 2012;141(suppl 2): e326s–e350s. Case 8 A 60-year-old woman is referred for preanesthesia medical evaluation prior to a left nephroureterectomy and retroperitoneal lymph node dissection for locally advanced urothelial carcinoma. Two years ago, she was discovered to have a high-grade urothelial carcinoma and underwent radical cystectomy and ileal conduit. Recurrence was discovered 6 months ago. She received neoadjuvant chemotherapy with carboplatin and gemcitabine. She has a 20-year history of multiple sclerosis. She currently does not ambulate but uses a scooter. She is able to transfer to her scooter. She can also do most of her activities of daily living. She has a history of osteoporosis and hypertension, both of which are well controlled. Her medications include amlodipine, lisinopril, baclofen, and alendronate. Her systems review is unremarkable. She specifically denies chest pain, shortness of breath, or syncope. Physical exam shows a 2/6 late-peaking systolic murmur heard best at the right upper sternal border and radiating to the carotids. The aortic closure sound (A2) is absent. Her pulse is of normal amplitude but does have a slight tardus contour. Her lungs are clear. She has 1þ edema below the knees. Her blood pressure is 135/80, with a heart rate of 76. An echocardiogram performed 6 years ago to evaluate a heart murmur was a technically limited study. She was thought to have aortic valve stenosis, with a valve area of 1.3 cm2 and a gradient of 28 mmHg. Her ejection fraction was 60%, and her right ventricular systolic pressure was normal. What do you recommend regarding her aortic stenosis? A. She most likely has moderate aortic stenosis and no further evaluation is required. B. Because her functional status is unclear, she should have a dobutamine stress echocardiogram prior to her noncardiac surgery. C. She likely has asymptomatic severe aortic stenosis but can undergo her noncardiac surgery with no further intervention. D. She should have a transthoracic echocardiogram before her surgery to better assess the status of her valve. If she has severe aortic stenosis, she should be evaluated for aortic valve replacement prior to her noncardiac surgery. E. She should be started on a beta blocker perioperatively. Discussion The management of asymptomatic aortic stenosis in the preoperative setting remains a clinical dilemma, as there is little data about the management of these patients in this setting.
M. Beliveau, J.B. Bundrick / Disease-a-Month 60 (2014) 402–411
411
For patients with severe, symptomatic aortic stenosis, the current ACC/AHA guidelines recommend aortic valve replacement prior to noncardiac surgery, especially if the surgery is high risk. Adverse outcomes have also been observed to occur more frequently in patients with co-existing mitral regurgitation and pre-existing coronary artery disease. A recent study of asymptomatic patients undergoing intermediate- or low-risk surgery concluded that these procedures could be done relatively safely in these patients, and this strategy is endorsed in the 2012 guideline of the European Society of Cardiology. The most common complication in this study was intraoperative hypotension. This patient presents a further challenge because her functional status is limited and she may not be truly asymptomatic. Her previous echocardiogram demonstrates moderate aortic stenosis, and her clinical examination suggests progression. If she has progressed to severe aortic stenosis, it is reasonable to consider valve replacement prior to a relatively high-risk surgical procedure. There is no role for perioperative beta blockade for aortic stenosis. Clinical pearl Patients with asymptomatic severe aortic stenosis can generally undergo low- and intermediate-risk noncardiac surgical procedures without significant risk of adverse events. References 1. Argarwal S, Rajamanickam A, Navkaranbir SB, et al. Impact of aortic stenosis on postoperative outcomes after noncardiac surgery. Circ Cardiovasc Qual Outcomes. 2013;6:193–200. 2. Calleja AM, Dommaraju S, Gaddam R, et al. Cardiac risk in patients 475 years with asymptomatic, severe aortic stenosis undergoing noncardiac surgery. Am J Cardiol. 2010;105: 1159–1163. 3. Vahanian A, Alfieri O, et al. for The Joint Task Force on the Management of Valvular Heart Disease of the European Society of Cardiology (ESC) and the European Association for CardioThoracic Surgery (EACTS). Guidelines on the management of valvular heart disease (version 2012). Eur J Cardiothorac Surg. 2012;42(4):S1–S44.
Answers: 1—A; 2—B; 3—E; 4—E; 5—D; 6—D; 7—D; 8—D.
Contents lists available at ScienceDirect
Disease-a-Month journal homepage: www.elsevier.com/locate/disamonth
Clinical pearls in perioperative medicine Margaret Beliveau, MD, John B. Bundrick, MD
Case 1 A 40-year-old woman with type 2 diabetes will undergo a laparoscopic cholecystectomy for symptomatic biliary colic. She has a history of severe postoperative nausea and vomiting after a cesarian section. Recently, her blood sugars have been poorly controlled. She is a non-smoker and does not use alcohol. She also has a history of hypertension, which is well controlled. Physical exam reveals a positive Murphy’s sign. Preoperative laboratory evaluation reveals normal creatinine, CBC, and electrolytes. Hemoglobin A1C is 9.0%. ECG shows heart rate of 72 and normal sinus rhythm, with a QTc of 0.46 s. The patient is very anxious about the possibility of another episode of severe postoperative nausea and vomiting. What is the best way to prevent postoperative nausea and vomiting in this patient? A. B. C. D. E.
Ondansetron 4 mg IV given at the end of surgery Dexamethasone 4 mg IV, given at induction Dronabinol 2.5 mg orally, given before induction Droperidol 1.25 mg IV, given at the end of surgery Metoclopramide 50 mg IV, given at the end of surgery.
Discussion Postoperative nausea and vomiting (PONV) can be seen in 30–50% of patients undergoing surgical procedures. Risk factors include female gender, non-smokers, history of postoperative nausea and vomiting or motion sickness, and use of postoperative opioids. Younger age ( o50 years) is also associated with an increased risk of PONV. Having 4/4 risk factors, as this patient does, is associated with an 80% risk of PONV. This patient also has a slightly increased QTc (normal o 0.45 s in women). A recent study demonstrated that perioperative doses of ondansetron did not lengthen the QT interval. This patient is diabetic, so dexamethasone, while effective, might worsen her blood sugar control, which is already not optimal. Cannabinoids have no role in the prevention of perioperative http://dx.doi.org/10.1016/j.disamonth.2014.04.018 0011-5029/& 2014 Mosby, Inc. All rights reserved.
M. Beliveau, J.B. Bundrick / Disease-a-Month 60 (2014) 402–411
403
nausea and vomiting. There is currently an FDA black box warning about the use of droperidol, although studies have demonstrated that the risk of QTC interval prolongation at lower doses is probably acceptable. Metoclopramide is not effective in preventing postoperative nausea and vomiting. It also may cause extrapyramidal side effects. Clinical pearl Ondansetron given at lower doses used for prophylaxis of PONV does not significantly prolong the QTC interval. References 1. Obal D, Yang D, Sessler D. Perioperative doses of ondansetron or dolasetron do not lengthen the QT interval. Mayo Clin Proc. 2014;89(1):69–80. 2. Apfel CC, Hiedrich FM, Jukar-Rao L, Hornuss C, Whalen RP, Zhang K, Cakmakkaya OS. Evidence-based analysis of risk factors for postoperative nausea and vomiting. Br J Anaesth. 2012(9):742–53.
Case 2 A 26-year-old man with sickle cell disease (Hg SS) is being seen for a preoperative medical evaluation. He is scheduled to undergo a right total hip arthroplasty because of avascular necrosis of the femoral head. He has a history of frequent pain crises. He is currently managed with hydroxyurea. He has recently been tested negative for HIV and Hepatitis B and C. He has received blood transfusions in the past and has had a history of an acute transfusion reaction 5 years ago. His baseline hemoglobin is 7.5 g/dL. What is the most appropriate recommendation for management in the perioperative setting? A. B. C. D. E.
Exchange transfusion to decrease the Hgb S level to o30% “Top-up” transfusion to increase the hemoglobin to 10.0 g/dL No transfusion preoperatively, transfuse only for postoperative complications “Top-up” transfusion to increase the hemoglobin to 4 12.0 g/dL Vigorous IV hydration for 6 h preoperatively
Discussion Patients with sickle cell disease are at risk for many postoperative complications. These patients are now living longer with their disease and are requiring surgical procedures for a variety of problems. Some of the most commonly performed procedures include cholecystectomy, ENT surgery, and orthopedic procedures for avascular necrosis of the femoral head. Preoperative transfusion can improve outcomes, especially for patients undergoing intermediate-risk procedures such as total hip arthroplasty. A large study published in 1995 did not demonstrate any benefit to exchange transfusion compared with “top-up” transfusion. However, this study did not include a cohort receiving no transfusion. The recent TAPS study demonstrated that preoperative transfusion decreased the risk of serious adverse events and postoperative complications. The most serious complication in patients who did not receive transfusions preoperatively was acute chest syndrome. Transfusion was aimed at increasing the hemoglobin to 10 g/dL or, in some cases, to achieve a hemoglobin S of less than 60%. Only one of the [#] patients in the transfusion group developed alloimmunization at 3 months.
404
M. Beliveau, J.B. Bundrick / Disease-a-Month 60 (2014) 402–411
Measures that help decrease the risk of complications in patients with sickle cell disease include vigorous hydration until the patient is able to take fluids by mouth, maintaining the oxygen saturation at greater than 96% and appropriate DVT prophylaxis. Clinical pearl “Top-up” transfusion to achieve hemoglobin of 10 g/dL will decrease the risk of sickle cellrelated perioperative complications. References 1. Howard J, Malfroy M, Choo L, et al. The transfusion alternatives preoperatively in sickle cell disease (TAPS) study: a randomized, controlled, multicentre clinical study. Lancet. 2013;381: 930–38. 2. Vichinsky EP, Haberkarn CM, Neumayr L, et al. A comparison of conservative and aggressive transfusion regimen in the perioperative management of sickle cell disease. The Preoperative Transfusion in Sickle Cell Disease Study Group. N Engl J Med. 1995;333:206–213. Case 3 A 40-year-old woman is being evaluated preoperatively. She has recently been found to have ovarian cancer and is scheduled for an exploratory laparotomy for staging and cytoreduction. She is obese, with a BMI of 37. She has a history of diet-controlled diabetes and obstructive sleep apnea, for which she uses CPAP. Her hemoglobin A1C is 7.5%. On physical exam, her blood pressure is 125/80. Her heart rate is 76. Heart and lung exams are normal. She does have trace pitting edema in her lower extremities, which she notes becomes worse as the day progresses. She has a normal ECG and chest X-ray. Her creatinine is normal. Her platelet count is 250,000. What is the most appropriate strategy for perioperative venous thromboembolism (VTE) prophylaxis in this patient? A. Rivaroxaban 20 mg once daily for 10 days after surgery B. Warfarin, adjusted to maintain an INR of 2.0–3.0, starting the day of surgery and continued for 14 days C. Mechanical compression with pneumatic compression sleeves, placed before surgery and continued until the patient is ambulatory D. Unfractionated heparin (UFH) 5000 units SQ twice daily until hospital discharge E. Low-molecular-weight heparin (LMWH) in prophylactic doses for 4 weeks postoperatively Discussion Patients with active malignancy are at an increased risk for perioperative VTE. Recent guidelines from the American Society of Clinical Oncology recommend that all patients with malignancy undergoing major surgical procedures receive appropriate pharmacologic prophylaxis, unless the patient has a contraindication such as a high bleeding risk. LMWH or UFH is recommended. The new oral anticoagulants, such as rivaroxaban, are not recommended in this situation. Warfarin is not recommended. Mechanical prophylaxis may provide increased protection when added to pharmacologic methods but are not sufficient when used alone. In patients undergoing major abdominal or pelvic surgery for cancer, who have other VTE risk factors (such as obesity, history of VTE, medical comorbidities, or restricted mobility), prophylaxis should be extended up to 4 weeks postoperatively.
M. Beliveau, J.B. Bundrick / Disease-a-Month 60 (2014) 402–411
405
Clinical pearl Patients with active malignancy undergoing major surgical procedures require extended pharmacologic prophylaxis with either LMWH or UFH. References 1. Lyman GH, Khorana AA, Kuderer NM, et al. Venous thromboembolism prophylaxis and treatment in patients with cancer: American society of Clinical Oncology Clinical Practice Guideline Update. J Clin Oncol. 2013;31:2189–2204. Case 4 A 98-year-old woman falls in her nursing home while ambulating with her walker. She sustains a right humerus and a right femoral neck fracture. The humeral fracture can be managed non-operatively. The orthopedist recommends surgical repair of the femoral fracture. The patient has a history of congestive heart failure, with grade 2/4 diastolic dysfunction. She also has a history of severe aortic stenosis but has refused surgery in the past. She has moderate dementia and chronic renal insufficiency. She also has history of atrial fibrillation. In the past, her heart rate has dropped into the 20s when beta blockers were given. Current medications include lisinopril, furosemide, and Celexa. A review of systems is obtained from her family. They deny any history of dyspnea with exertion. She has no history of chest pain. She has no history of syncope and is able to ambulate with her walker. On exam, her heart rate is 61 and is irregular. Her blood pressure is 130/80. She has a 3/6 latepeaking systolic murmur. Her lungs are clear. She has no edema. Laboratory evaluation shows hemoglobin of 10, MCV of 106, and creatinine of 1.7, all of which are unchanged from a year prior. Her ECG shows atrial fibrillation, with a prolonged QTC and left anterior fascicular block. The patient has told her family in the past that she does not want to live if she cannot be ambulatory. She currently has a DNR order in place. Which of the following is true regarding the DNR order? A. The DNR order must be rescinded before the patient goes to the OR B. She (or her surrogates) are more likely to refuse surgery because she has a pre-existing DNR order C. If the patient refuses to rescind the DNR order, the surgeon has the right to refuse to operate on her D. Her risk of death is no different than a patient who does not have a pre-existing DNR order E. It is acceptable for her to delegate decisions about perioperative resuscitation to her care team Patients have a right to self-determination, and this is the supreme standard in medical ethics. The American Society of Anesthesiologists, and other professional organizations, has long stated that automatic suspension of a DNR order for surgery will violate the patient’s right to self-determination. Studies have shown that patients with DNR orders will consent to surgery if the surgery will help in the palliation of pain or in the maintenance of quality of life. Patients are also willing to accept “aggressive” interventions for conditions that are not immediately related to their primary medical illnesses. Scarborough and Pappas showed that DNR patients having emergency surgery have a higher risk of death within 30 days. The DNR order has been shown to be an independent predictor of postoperative mortality in patients undergoing emergency surgery. This appears to be primarily related to the development of postoperative complications. While patients with DNR orders have a similar rate of postoperative complications when compared to patients who do not have
406
M. Beliveau, J.B. Bundrick / Disease-a-Month 60 (2014) 402–411
DNR orders, patients with DNR orders are more likely to die as a result of these complications. This appears to be due to decreased willingness to aggressively treat major complications. Most patients expect that there would be a detailed discussion with their care team regarding their goals of care and personal values. It is acceptable for patients to delegate perioperative decisions regarding appropriate intervention to the anesthesiologist or surgeons, once the context of the patient’s stated goals and values has been considered. Clinical pearl DNR orders help identify a patient’s goals and values. They should not be automatically rescinded in the OR. A detailed discussion regarding a patient’s goals of care is critical prior to a surgical procedure. References 1. Burkle CM, Swetz KM, Armstrong MH, Keegan MT. Patient and doctor attitudes and beliefs concerning perioperative do not resuscitate orders: anesthesiologists’ growing compliance with patient autonomy and self determination guidelines. BMC Anesthesiol. 2013;13:2. 2. Scarborough JE, Pappas TN. The effect of do-not-resuscitate status on postoperative mortality in the elderly following emergency surgery. AdvSurg. 2013;47:213–225. 3. Scott TH, Gavin JR. Palliative surgery in the do-not-resuscitate patient: ethical and practical suggestions for management. Anesthesiol Clin. 2012;30:1–12. Case 5 A 78-year-old man has a history of recurrent bladder cancer. He has undergone radiation therapy and chemotherapy and failed both of these. He has developed persistent hematuria and is now transfusion dependent. He is being seen for preoperative evaluation prior to a planned curative cystectomy. Eight months ago, he complained of fatigue and exertional chest discomfort despite having normal hemoglobin. He was found to have an abnormal ECG and ultimately underwent cardiac catheterization. He had two drug-eluting stents placed, in the left anterior descending and right coronary arteries. The patient has since been asymptomatic. Adenosine–sestamibi test performed in anticipation of his surgery was positive for a small area of reversible inferior ischemia. He was evaluated by his cardiologist, who felt that the benefit of the surgical procedure outweighed the cardiac risk. He was thought to be medically optimized. Current medications include aspirin 81 mg daily and clopidogrel 75 mg daily. His medications also include metoprolol, lisinopril, and atorvastatin. His functional status is less than 4 mets. His resting pulse rate is 60. What recommendations should you make regarding his dual antiplatelet therapy? A. The patient should undergo the surgical procedure on aspirin and clopidogrel. B. The administration of aspirin should be stopped, but the administration of clopidogrel should be continued. C. The administration of aspirin and clopidogrel can be interrupted for the surgical procedure. D. The administration of clopidogrel can be stopped, but the administration of aspirin should be continued. E. The administration of aspirin and clopidogrel should be discontinued and the patient should be bridged with low-molecular-weight heparin.
M. Beliveau, J.B. Bundrick / Disease-a-Month 60 (2014) 402–411
407
Discussion In the United States, as many as 900,000 patients receive coronary stents annually. The majority of these are drug-eluting stents. Up to 5% of patients with recently implanted stents will require surgery within a year of stent placement. The major risk factor for stent thrombosis is premature discontinuation of dual antiplatelet therapy. The mortality rate from stent thrombosis is as much as 40–50%. Current guidelines recommend that dual antiplatelet therapy be continued for a period of 12 months after the placement of drug-eluting stents. Most current guidelines recommend continuing antiplatelet therapy in the perioperative setting, unless there is a high bleeding risk. Additional recommendations include delaying elective surgery until a year after stent placement. There is considerable controversy about management of patients who require nonelective surgery after stent placement. A recent large study of patients undergoing noncardiac surgery within 2 years of stent placement showed that major adverse cardiac events were associated with emergency surgery and a Revised Cardiac Risk Index (RCRI) of 42. Timing of surgery, beyond 6 months after stent implantation, was not significantly associated with major adverse cardiac events. Management of dual antiplatelet therapy should be individualized, based on the bleeding risk of the surgery, as well as the patient’s risk of thrombosis. High risk of stent thrombosis can be seen in patients with long stents, in multiple or overlapping stents, in stents at bifurcations, and in patients with recent acute coronary syndrome, prior history of stent thrombosis, chronic kidney disease, and diabetes. While the procedure for this patient may be associated with an increased risk of bleeding, most guidelines would advise that continuation of aspirin would be recommended for prevention of stent thrombosis. There is no role for bridging with lowmolecular-weight heparin. Clinical pearl Management of dual antiplatelet therapy in patients with cardiac stents who require noncardiac surgery remains unclear. New data indicates that after 6 months, patients with low risk of stent thrombosis may be managed with aspirin alone in the perioperative setting. References 1. Hawn MT, Graham LA, Richmond JS, et al. Risk of major adverse cardiac events following noncardiac surgery in patients with coronary stents. J Am Med Assoc. 2013;310(14):1462– 1472. 2. Capodanno D, Angiolillo DJ. Management of antiplatelet therapy in patients with coronary artery disease requiring cardiac and noncardiac surgery. Circulation. 2013;128:2785–2798. 3. Darvish-Kazem S, Gandhi M, Marcucci M, Douketis JD. Perioperative management of antiplatelet therapy in patients with coronary stent who need noncardiac surgery. Chest. 2013;144(6):1848–1856. 4. Hawn MT, Graham LA, Richman JR, et al. The Incidence and timing of noncardiac surgery after cardiac stent implantation. J Am Coll Surg. 2012;214:658–657. Case 6 A 60-year-old man is being evaluated preoperatively in anticipation of robotic prostatectomy for a Gleason 3 þ 3 prostate adenocarcinoma. He was initially managed with hormonal therapy. However, the patient preferred to have a prostatectomy performed. His past medical history is significant for morbid obesity, with a body mass index of 44. He has no history of hypertension, coronary artery disease, pulmonary disease, kidney disease, or hyperlipidemia. He was noted to have impaired fasting blood sugar, with a fasting blood sugar of 118. He is a construction worker and is quite physically active. He denies any shortness of breath or chest discomfort. He is a never-smoker.
408
M. Beliveau, J.B. Bundrick / Disease-a-Month 60 (2014) 402–411
On physical exam, his weight is 134.6 kg, with a height of 173.6 cm. Waist circumference is 134 cm. Neck circumference is 42 cm. The patient notes that his wife now sleeps in a different room, because of his snoring. He also notes that if he sits down to watch television or read, he will often fall asleep. He has fallen asleep while driving once. Laboratory evaluation reveals hemoglobin of 15.6. Fasting blood sugar is 118. His electrolytes are normal. His creatinine is normal at 1.0. ECG shows normal sinus rhythm with first-degree AV block. Surgical procedure is planned for tomorrow. What do you recommend to the surgeon? A. The patient is medically optimized for surgery, and nothing further needs to be done. B. The patient is at high risk for OSA. Surgery should be postponed until a polysomnogram can be performed. C. The patient should be screened with the STOP-BANG questionnaire. If his score is suggestive of OSA, surgery should be postponed until a polysomnogram can be performed. D. The patient should be presumed to have OSA and should be monitored for respiratory events in the PACU. If respiratory events occur, he should be monitored for 24–48 h postoperatively. E. The patient is at high risk for OSA and should not receive opioids postoperatively. Discussion Obstructive sleep apnea (OSA) has been associated with numerous perioperative complications, including hypoxemia, cardiac arrhythmias, myocardial ischemia, reintubation, unexpected ICU admission, and sudden death. These patients often have multiple medical comorbidities, which put them at an increased risk. Many anesthetic agents promote airway collapse and respiratory depression. In addition, these patients often require postoperative opioids, and this further increases the risk of respiratory suppression. Many patients are suspected to have OSA when they undergo preoperative evaluation. There are multiple instruments available to screen for OSA. The STOP-BANG questionnaire is quite useful in identifying patients at higher risk. The acronym designates eight symptoms and signs associated with OSA, and a score of three or greater indicates a high probability of OSA. An optimal management strategy for patients with suspected obstructive sleep apnea who are undergoing surgery has not been clearly defined. There is no clear evidence that a polysomnogram and preoperative positive airway pressure will improve surgical outcomes. The optimal time for treating the patients with PAP preoperatively is unknown. The Society for Ambulatory Anesthesia recommends that if a patient is suspected to have OSA, the surgical team should proceed under the assumption that the patient in fact does have OSA. Gali et al. have demonstrated that the Respiratory-Specific Assessment in the PostAnesthesia Care Unit (PACU) can be used to identify patients at an increased risk of postoperative complications of OSA. These patients should be monitored remotely for desaturation in the postoperative setting, especially if the use of opioids for pain management is anticipated. It is not reasonable to simply withhold opioids in a patient who would otherwise require them. Clinical pearl Patients who are identified preoperatively as being at a high risk for OSA should be monitored in the PACU for respiratory events. Patients with evidence of respiratory events in the PACU should be admitted to a monitored unit. References 1. Gali B, Whalen FX, Schroeder DR et al. Identification of patients at risk for postoperative respiratory complications using a preoperative obstructive screening tool and postanesthesia care assessment. Anesthesiology. 2009;110:869–877.
M. Beliveau, J.B. Bundrick / Disease-a-Month 60 (2014) 402–411
409
2. Weingarten TN, Kor BJ, Gali B, Sprung J. Predicting postoperative pulmonary complications in high risk populations. Curr Opin Anesthiol. 2013;26:116–125. 3. Joshi GP, Ankichetty SP, Gan TJ, Chung F. Society for Ambulatory Anesthesia consensus statement on preoperative selection of adult patients with obstructive sleep apnea scheduled for ambulatory surgery. Anesth Analg. 2012;115:1060–1068. 4. Adesanya AO, Grelich NB, Joshi GP. Perioperative management of obstructive sleep apnea. Chest. 2010;138(6):1489–1498. 5. Auckley D, Bolden N. Preoperative screening and perioperative care of the patient with sleepdisordered breathing. Curr Opin Pulm Med. 2012;18:588–595. Case 7 A 75-year-old man is scheduled for a right hemicolectomy. He has a history of atrial fibrillation. He has no history of stroke. He does have hypertension, which is well controlled on metoprolol. He is not diabetic. His last echocardiogram showed a dilated left atrium. He is currently on dabigatran 150 mg twice daily. His creatinine clearance is 62 mL/min. He has a history of gastroesophageal reflux, currently treated with omeprazole 20 mg daily. He has an excellent functional status. On physical examination, his blood pressure is 130/85, with a heart rate of 62. His heart rhythm is irregular. His lungs are clear. He has no edema. Routine DVT prophylaxis with low-molecular-weight heparin is planned postoperatively. What do you recommend regarding the dabigatran? A. Dabigatran should be discontinued 5 days before the planned surgical procedure. B. Dabigatran should be discontinued 5 days before the planned surgical procedure and lowmolecular-weight heparin should be started 3 days before the procedure. C. Dabigatran should be discontinued 3 days before the planned surgical procedure, check prothrombin time preoperatively D. Dabigatran should be discontinued 3 days before the planned surgical procedure E. If the patient develops a postoperative ileus, therapeutic doses of low-molecular-weight heparin should be given until bowel function returns. Discussion The perioperative management of oral anticoagulants is determined by a number of clinical issues. Dabigatran is a direct thrombin inhibitor. It is not highly protein bound. Unlike vitamin K antagonists, it does not require routine coagulation monitoring. It has been approved for stroke prevention in patients with nonvalvular atrial fibrillation. Because it is cleared by the kidney, it is contraindicated if the creatinine clearance is less than 30 mL/min. The timing of preoperative discontinuation is determined by the creatinine clearance and the bleeding risk of the procedure. In a patient with a creatinine clearance of 50–80 mL/min, dabigatran can be discontinued one day prior to the planned surgical procedure if it is a low bleeding risk procedure. For high bleeding risk procedures, the current recommendation is discontinuing this drug 2–4 days preoperatively. There is no need to hold the medication for more than 2–4 days. This is a high bleeding risk procedure, so a recommendation of discontinuing dabigatran 2–3 days in advance would be appropriate. While dabigatran does slightly prolong the prothrombin time in a dose-dependent manner, this lab test is insensitive for measuring the antithrombotic effect of the drug and is not recommended. This patient has a CHADS-2 score of two. He would be considered low risk for a thromboembolism. Therefore, he does not require any bridging therapy preoperatively. In situations where the absorption of dabigatran would be impaired, for example, postoperative ileus, the drug should be held until the return of bowel function. While this patient does need DVT prophylaxis, if he should develop an ileus, there would be no need for therapeutic doses of low-molecular-weight heparin.
410
M. Beliveau, J.B. Bundrick / Disease-a-Month 60 (2014) 402–411
Clinical pearl In patients with normal renal function, dabigatran can be discontinued 1 day preoperatively for low bleeding risk procedures and 2–4 days preoperatively for high bleeding risk procedures. References 1. Levy JH, Faraoni D, Spring JL, Douketis JD, Samama CM. Managing new oral anticoagulants in the perioperative and intensive care unit setting. Anesthesiology. 2013;118:1466–1474. 2. Spyropoulos AC, Douketis JD. How I treat anticoagulated patients undergoing an elective procedure or surgery. Blood. 2012;120:2954–2962. 3. Douketis JD, Spyropoulos AC, Spencer FA, et al. Perioperaitve management of antithrombotic therapy: antithrombotic therapy and prevention of thrombosis, 9th ed.: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. Chest. 2012;141(suppl 2): e326s–e350s. Case 8 A 60-year-old woman is referred for preanesthesia medical evaluation prior to a left nephroureterectomy and retroperitoneal lymph node dissection for locally advanced urothelial carcinoma. Two years ago, she was discovered to have a high-grade urothelial carcinoma and underwent radical cystectomy and ileal conduit. Recurrence was discovered 6 months ago. She received neoadjuvant chemotherapy with carboplatin and gemcitabine. She has a 20-year history of multiple sclerosis. She currently does not ambulate but uses a scooter. She is able to transfer to her scooter. She can also do most of her activities of daily living. She has a history of osteoporosis and hypertension, both of which are well controlled. Her medications include amlodipine, lisinopril, baclofen, and alendronate. Her systems review is unremarkable. She specifically denies chest pain, shortness of breath, or syncope. Physical exam shows a 2/6 late-peaking systolic murmur heard best at the right upper sternal border and radiating to the carotids. The aortic closure sound (A2) is absent. Her pulse is of normal amplitude but does have a slight tardus contour. Her lungs are clear. She has 1þ edema below the knees. Her blood pressure is 135/80, with a heart rate of 76. An echocardiogram performed 6 years ago to evaluate a heart murmur was a technically limited study. She was thought to have aortic valve stenosis, with a valve area of 1.3 cm2 and a gradient of 28 mmHg. Her ejection fraction was 60%, and her right ventricular systolic pressure was normal. What do you recommend regarding her aortic stenosis? A. She most likely has moderate aortic stenosis and no further evaluation is required. B. Because her functional status is unclear, she should have a dobutamine stress echocardiogram prior to her noncardiac surgery. C. She likely has asymptomatic severe aortic stenosis but can undergo her noncardiac surgery with no further intervention. D. She should have a transthoracic echocardiogram before her surgery to better assess the status of her valve. If she has severe aortic stenosis, she should be evaluated for aortic valve replacement prior to her noncardiac surgery. E. She should be started on a beta blocker perioperatively. Discussion The management of asymptomatic aortic stenosis in the preoperative setting remains a clinical dilemma, as there is little data about the management of these patients in this setting.
M. Beliveau, J.B. Bundrick / Disease-a-Month 60 (2014) 402–411
411
For patients with severe, symptomatic aortic stenosis, the current ACC/AHA guidelines recommend aortic valve replacement prior to noncardiac surgery, especially if the surgery is high risk. Adverse outcomes have also been observed to occur more frequently in patients with co-existing mitral regurgitation and pre-existing coronary artery disease. A recent study of asymptomatic patients undergoing intermediate- or low-risk surgery concluded that these procedures could be done relatively safely in these patients, and this strategy is endorsed in the 2012 guideline of the European Society of Cardiology. The most common complication in this study was intraoperative hypotension. This patient presents a further challenge because her functional status is limited and she may not be truly asymptomatic. Her previous echocardiogram demonstrates moderate aortic stenosis, and her clinical examination suggests progression. If she has progressed to severe aortic stenosis, it is reasonable to consider valve replacement prior to a relatively high-risk surgical procedure. There is no role for perioperative beta blockade for aortic stenosis. Clinical pearl Patients with asymptomatic severe aortic stenosis can generally undergo low- and intermediate-risk noncardiac surgical procedures without significant risk of adverse events. References 1. Argarwal S, Rajamanickam A, Navkaranbir SB, et al. Impact of aortic stenosis on postoperative outcomes after noncardiac surgery. Circ Cardiovasc Qual Outcomes. 2013;6:193–200. 2. Calleja AM, Dommaraju S, Gaddam R, et al. Cardiac risk in patients 475 years with asymptomatic, severe aortic stenosis undergoing noncardiac surgery. Am J Cardiol. 2010;105: 1159–1163. 3. Vahanian A, Alfieri O, et al. for The Joint Task Force on the Management of Valvular Heart Disease of the European Society of Cardiology (ESC) and the European Association for CardioThoracic Surgery (EACTS). Guidelines on the management of valvular heart disease (version 2012). Eur J Cardiothorac Surg. 2012;42(4):S1–S44.
Answers: 1—A; 2—B; 3—E; 4—E; 5—D; 6—D; 7—D; 8—D.
