#135 Perioperative Medicine: Assess & Optimize Risk

January 14, 2019 | By Matthew Watto, MD

With Avital O’Glasser MD of OHSU

Optimize perioperative risk and dominate perioperative medicine. Topics include surgical risk calculators, preoperative labs, stress testing, use of BNP and troponins, postoperative MI, cardiac and pulmonary risk stratification, and more! We’re joined by perioperative medicine expert, Avital O’Glasser MD, Associate Professor of Medicine at Oregon Health & Science University and Assistant Program Director for Scholarship and Social Media. ACP members can visit https://acponline.org/curbsiders to claim free CME-MOC credit for this episode and show notes (goes live 0900 EST).

Join ACP’s Internal Medicine Meeting 2019 April 11-13th in Philadelphia, PA. We’ll see you there!

Full show notes available at http://thecurbsiders.com/podcast. Join our mailing list and receive a PDF copy of our show notes every Monday. Rate us on iTunes, recommend a guest or topic and give feedback at thecurbsiders@gmail.com.

Credits

Written and produced by: Matthew Watto MD

CME questions by: Matthew Watto MD

Hosts: Matthew Watto MD, Stuart Brigham MD

Edited by: Matthew Watto MD

Guest: Avital O’Glasser MD

Time Stamps

• 00:00 Disclaimer, intro and guest bio
• 04:20 Guest one-liner, book and movie recommendations, career advice
• 11:20 ACP Internal Medicine Meeting 2019 details
• 14:02 Patient with coronary artery calcifications going for elective hip surgery and wants “clearance”
• 20:50 Functional capacity
• 25:00 Preoperative stress testing and coronary revascularization
• 31:55 Canadian guidelines, BNP and troponin testing
• 36:30 The METS trial and predicting perioperative cardiac events and mortality
• 40:44 Preoperative testing (labs, imaging, urine studies)
• 50:24 Choosing your perioperative cardiac and surgical risk calculator (RCRI, MICA, ACS-NSQIP)
• 59:50 Communicating risk to patient and their surgeon
• 61:30 Pulmonary risk assessment and complications
• 70:35 Perioperative use of opioids
• 75:30 Who needs an echocardiogram prior to surgery?
• 79:00 Canceling a patient’s surgery
• 82:55 Take home points
• 83:45 Outro

“The preoperative consultation may represent the first careful cardiovascular evaluation for a patient in years, or in some instances…ever”

Dr O’Glasser paraphrasing the 2007 ACC/AHA guidelines

“Think of the evaluation (assessment) as pertaining to this patient for this surgery with this surgeon at this time and maybe even at this venue…for this surgical indication.”

Dr O’Glasser’s perioperative medicine mantra

Perioperative Risk Assessment Pearls

1. The goal is to assess and optimize risk. This is NOT preoperative clearance!
2. The recent METS trial questions the utility of subjective METS assessment. The Duke Activity Score Index performed better and may drive changes to the next guidelines update. Stay tuned [Wijeysundera Lancet 2018 – PMID 30070222].
3. It is reasonable to use any of the three surgical calculators (RCRI, MICA, or ACS-NSQIP) as part of your perioperative medicine evaluation [Cohn Am J Cardiol 2018 – PMID 29126584].
4. Rule of thumb for preoperative test and labs: Most tests aren’t indicated unless you would have ordered them in the absence of surgery. -Dr O’Glasser. See Table 2 in Cohn Annals Int Med 2016 for specific indications by test.
5. While preoperative coronary revascularization does not seem to prevent postoperative cardiac events or death [Cohn Annals Int Med 2016], preoperative stress testing may inform perioperative medical and surgical management for select patients.
6. Similarly, an echocardiogram can estimate pulmonary and cardiac pressures, ejection fraction and identify valvular lesions. This information can inform the perioperative management, which includes preoperative, intraoperative and postoperative care. -Dr O’Glasser’s expert opinion.
7. The majority with myocardial injury after noncardiac surgery (MINS) are clinically asymptomatic. Some guidelines recommend screening for MINS [Duceppe CJC 2017]. BUT, optimal management strategies are not yet known [Devereaux Lancet 2018]. Therefore, this practice is not yet widespread.
8. Pulmonary complications may be more common and costly than cardiac complications [Qaseem Ann Int Med 2006 ; Sabate Curr Opin Anaesthesiol. 2014]. Dr O’Glasser especially watches out for obesity hypoventilation and right heart failure.
9. Counseling patients about perioperative pain including expected pain level and plan for pain management may improve perceived pain scores and decrease the needs for narcotic pain medications [Altman JAMA Otolaryngol 2017 – PMC5824296].

Perioperative Medicine – In-Depth Show Notes

Perioperative Medicine Goals

1. Make the risk as low as possible for a given patient (i.e. optimize their medical condition/readiness for surgery). This is NOT clearance. -Dr O’Glasser
2. Qualify and quantify the known medical conditions. Plus, perform a detailed history and exam to identify the “as yet undiagnosed” conditions. -Dr O’Glasser

Subject assessment of functional capacity: Is it useful?

The METS Trial compared subjective METS (metabolic equivalents) vs the DASI (Duke Activity Index) vs stress testing vs BNP. The DASI performed best for predicting postoperative events [Wijeysundera Lancet 2018 – PMID 30070222]. Dr O’Glasser notes that this study may drive changes to the next guidelines update (i.e. use of DASI rather than subjective measures of functional status/METS).

For the time being, Dr O’Glasser still takes a history that includes subjective estimate of functional capacity. Check out whyiexercise.com to estimate METS.

Surgical Risk calculators

Dr O’Glasser often combines information from multiple risk calculators based on their strengths and weaknesses. Check out this paper by perioperative medicine guru, Steve Cohn MD comparing risk calculators [Cohn Am J Cardiol 2018 – PMID 29126584].

Dr O’Glasser recommends using the ACS NSQIP surgical risk calculator for more medically complex patients. It predicts length of stay, the need for rehab, and risk of non-cardiac post-op complications, and more (see example).

The RCRI is the oldest and has been externally validated for predicting major adverse cardiac events. It may overestimate the risk for low risk surgical procedures and underestimate the risk for major vascular surgeries  [Cohn Annals Int Med 2016 – PMID 27919097].

The “myocardial infarction or cardiac arrest” calculator aka MICA (aka Gupta) may perform best at identifying high risk patients [Cohn Am J Cardiol 2018 – PMID 29126584].

Bottom line: It is reasonable to use any of the three calculators as part of your perioperative medicine evaluation.

Preoperative testing

Universal preoperative screening labs are low value care. Decide on which labs by the history and physical.

Bottom line: Most tests aren’t indicated unless you would have ordered them in the absence of surgery. -Dr O’Glassers expert recommendation

Get to know your surgical colleagues. Then, dissuade them from low value preoperative testing. –Paraphrasing Dr O’Glasser on The Curbsiders

Specific cases where labs may be warranted (Dr O’Glasser’s recommendations)

1. Coags – Are low value care in the absence of a personal or family bleeding history.
2. Complete blood count – Reasonable if expected blood loss or risk for anemia.
3. Basic metabolic panel – Check if on an ACEI, ARB, diuretic, NSAIDS or history of kidney disease or hypertension.
4. Type and screen – Reasonable if a large amount of blood loss is expected.
5. Liver function panel – Low value test unless patient has known liver disease or major risk factors.
6. Albumin and prealbumin – Low values are a poor prognostic indicator. BUT, “correcting hypoalbuminemia” should not be pursued [Kim. Am Surg. 2017 – PMID 29183523]. Recall that these are markers of inflammation and/or illness burden, NOT nutritional status! (The Curbsiders #109 TWDFNR)
7. Urinalysis – Indicated prior to genitourinary procedures. Otherwise, it’s a low value test.
8. Chest xray – Not recommended as standard practice Choosing Wisely Campaign.

Coronary Artery Disease

Ask yourself

Is their CAD well controlled? Are my patient’s cardiac risk factors optimized (e.g. diabetes, smoking, blood pressure)?

The patient with prior myocardial infarction (MI) who now has well controlled risk factors and is exercising has a much different risk profile than a patient with the same cardiac history, but poorly controlled risk factors and poor functional capacity. –Paraphrasing Dr O’Glasser on The Curbsiders

Preoperative stress testing

In general, preoperative stress testing is NOT recommended for asymptomatic patients [Cohn Annals Int Med 2016]. It’s warranted ONLY if needed to work up a patient’s symptoms (i.e. you would have ordered it even absent a plan to pursue surgery). -Dr O’Glasser

It should be noted that preoperative revascularization was not shown to improve mortality in patients with stable angina (The CARP trial – NEJM 2004l). Similarly, in patients with positive dobutamine stress echocardiography, revascularization did not lower the rate of postoperative MI or death at 30 days or 1 year (The DECREASE V trial – PMID: 17466225).  —Cohn SL. In the Clinic: Preoperative Evaluation for Noncardiac Surgery. Annals Int Med. Dec 2016. doi:10.7326/AITC201612060

The “Dreaded Step 6” from the 2014 ACC/AHA guidelines

“Will further testing impact decision making OR effect perioperative care?” -2014 ACC/AHA Periop Guidelines JACC 2014

Dr O’Glasser notes preoperative revascularization hasn’t been shown to improve outcomes (e.g. prevent postoperative MI or death). BUT, stress testing may help inform risk/benefit discussions, and influence medical therapy, type of anesthesia, surgical setting, and other nuanced perioperative decisions!!!!

What about postoperative myocardial INJURY (MINS)?

About 65 percent of patients with myocardial injury after noncardiac surgery (MINS) are clinically asymptomatic [Duceppe CJC 2017]. Cardiac troponin testing increases the sensitivity to detect MINS. Patients with MINS after noncardiac surgery have a poor prognosis [Duceppe CJC 2017]. MINS is an independent predictor of 30-day and 1-year mortality [Botto et al Anesthesiology 2014 PMID 24534856; MANAGE Trial page ClinicalTrials.gov].

In the MANAGE Trial, MINS was defined by elevated cardiac troponins with either 1) symptoms of ischemia 2) ischemic EKG changes 3) wall motion abnormalities on echocardiogram OR elevated troponin after surgery with no alternative explanation (e.g., pulmonary embolism, sepsis) for myocardial injury. [Devereaux Lancet 2018]

The MANAGE trial tested dabigatran versus placebo for MINS. It found a slight decrease in the composite outcome of “major vascular events” without a significant increase in major bleeding [Devereaux Lancet 2018].

Canadian Perioperative Medicine Guidelines

The Canadian guidelines recommend checking preoperative BNP or NT-proBNP for select patients with at least a five percent risk of cardiac events within 30 days of surgery [Duceppe CJC 2017].

Check daily cardiac troponins and postoperative EKG (in the PACU) for patients with preoperative BNP above 92 or NT-proBNP above 300 [Duceppe CJC 2017].

Bottom line: MINS is common and often asymptomatic. That said, Dr O’Glasser and her friends in perioperative medicine are not currently following the Canadian guidelines and experts are still gathering data on how to treat MINS.

Who needs a Preoperative Echocardiogram?

Dr O’Glasser recommends an echocardiogram for patients who meet criteria of 2014 ACC/AHA guidelines, “unexplained dyspnea, heart failure with a change in condition, or suspected valve disease (as well as those with known valvular disease who are overdue for imaging) –2014 ACC/AHA Periop Guidelines JACC 2014.

NOTE: The echocardiogram can estimate pulmonary and cardiac pressures, ejection fraction and identify valvular lesions. This information can inform the perioperative management, which includes preoperative, intraoperative and postoperative care. -Dr O’Glasser’s expert opinion.

Perioperative Medicine & Pulmonary Complications

Pulmonary complications may be more common and costly than cardiac complications [Qaseem Ann Int Med 2006 ; Sabate Curr Opin Anaesthesiol. 2014]

Obstructive sleep apnea (OSA), obesity hypoventilation syndrome (OHVS) and pulmonary hypertension are the pulmonary conditions that get Dr O’Glasser’s attention. An elevated serum bicarbonate or low resting oxygen saturation should raise the level of concern.  Uncontrolled OHVS can be a reason to cancel or postpone surgery until patient is optimized. -Dr O’Glasser’s expert opinion

Practical strategies to lower pulmonary risk:

Use local instead of general anesthesia; hospital instead of ambulatory surgical center; 23 hour observation instead of same day discharge; sleep in recliner instead of flat in bed; minimize post-op opioids; and ensure family member supervision night of surgery. -Dr O’Glasser’s expert opinion

Post-operative opioid prescribing

Counseling patients about perioperative pain including expected pain level and plan for pain management may improve perceived pain scores and decrease the needs for narcotic pain medications [Altman JAMA Otolaryngol 2017 – PMC5824296].

Goals

Listeners will develop a systematic and evidence based approach to perioperative risk evaluation and medical optimization.

Learning objectives

After listening to this episode listeners will…

1. Define the goals of a perioperative evaluation
2. Identify high value perioperative testing
3. Differentiate  and choose between the various perioperative cardiovascular risk assessment tools
4. Recall the significance of myocardial injury after noncardiac surgery and possible future directions
5. Evaluate and mitigate risk for perioperative complications

Disclosures

Dr O’Glasser reports no relevant financial disclosures. The Curbsiders were sponsored by the American College of Physicians for this episode.

Links from the show

Citations are embedded in the text.

1. Wild (book) by Cheryl Strayed
2. What Alice Forgot (book) by Liane Moriarty
3. Idiocracy (film) by Mike Judge