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Resident Version

Preoperative Evaluation Module

Cardiac

created by Dr. Meg Lieberman

Updated Deepti Rao11/1/11

Objectives:

  1. Be able to identify patients at significant risk for perioperative cardiac morbidity.
  2. Identify strategies to moderate that risk.

References:

1. Fleisher LA, Beckman JA, Brown KA, et al.,ACC/AHA 2007 guideline on perioperative cardiovascular evaluation and care for noncardiac surgery: A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee to revise the 2002 Guidelines on Perioperative Cardiovascular Evaluation for Noncardiac Surgery) J Am Coll Cardiol 2007;50:e159-242.

2. Lee TH, Marcantonio ER, Mangione CM, et al, Derivation and Prospective Validation of a Simple Index for Prediction of Cardiac Risk of Major Noncardiac Surgery.Circulation 1999;100:1043-9.

3. Devereaux PJ; Goldman L; Cook DJ; et al, Perioperative cardiac events in patients undergoing noncardiac surgery: a review of the magnitude of the problem, the pathophysiology of the events and methods to estimate and communicate risk. CMAJ 2005 Sep 13;173(6):627-34.

4. Effects of extended-release metoprolol succinate in patients undergoing non-cardiac surgery (POISE trial): a randomised controlled trial.Lancet. 2008 May 31;371(9627):1839-47.

5. Lindenauer PK, Pekow P, Wang K, Perioperative Beta Blocker Therapy and Mortality After Major Surgery.NEJM 2005;353:349-61.

Goals of Preoperative Medical Consultation:

  1. To assess the patient for known and unknown problems which are likely to affect surgical morbidity.
  2. To determine, in the setting of those problems and the proposed procedure, the risk to the patient
  3. To intervene to minimize those risks (and optimize the patient) or to delay or change the proposed procedure
  4. To recognize potential complications of the procedure and recommend prophylaxis for those complications or help to treat those complications

CARDIAC EVALUATION:

Cardiovascular risks are some of the highest risks patients undergo when having major surgery, not only due to surgical factors like volume shifts, blood loss and increased myocardial oxygen demands but also due to patient factors both known and unknown.

One of the more commonly used algorithms for assessing cardiac risk is the 2007 ACC/AHA guideline (1). It is evidence based and a collaboration of multiple societies including not only cardiologists but also anesthesiologists. (See back for a table outlining the schema for the classification of recommendations level of evidence)

Cardiac evaluation and care algorithm for noncardiac surgery based on active clinical conditions, known cardiovascular disease, or cardiac risk factors for patients 50 years of age or greater

ACC/AHA: American College of Cardiology/American Heart Association; HR: heart rate; LOE: level of evidence; MET: metabolic equivalent..
Clinical risk factors include ischemic heart disease, compensated or prior heart failure, diabetes mellitus, renal insufficiency, and cerebrovascular disease.
Consider perioperative beta blockade (see Table 5) for populations in which this has been shown to reduce cardiac morbidity/mortality.

Step 1: Need for emergency noncardiac surgery?

This is relatively straight forward. If a patient has a condition requiring emergency surgery, for examples/p mva with a ruptured spleen,then preoperative evaluation of cardiac risk is unnecessary. These patients, if there is some concern about cardiac issues, should be assessed post op.

Step 2: Active cardiac conditions

Major predictors that require intensive management and may lead to delay in or cancellation of the operative procedure

  • Unstable coronary syndromes including unstable or severe angina or recent MI
  • Decompensated heart failure including NYHA functional class IV or worsening or new-onset HF
  • Significant arrhythmias including high grade AV block, symptomatic ventricular arrhythmias, supraventricular arrhythmias with ventricular rate > 100 bpm at rest, symptomatic bradycardia, and newly recognized ventricular tachycardia
  • Severe heart valve disease including severe aortic stenosis or symptomatic mitral stenosis

These “active cardiac conditions” should cause at least a close evaluation if not further intervention and/or reconsideration of a surgery.

Step 3: Low risk surgery?

ACC/AHA guideline summary: Cardiac risk stratification for noncardiac surgical procedures

High risk (reported risk of cardiac death or nonfatal myocardial infarction [MI] often)

  • Aortic and other major vascular surgery
  • Peripheral arterial surgery

Intermediate risk (reported risk of cardiac death or nonfatal MI generally 1 to 5 percent)

  • Carotid endarterectomy
  • Head and neck surgery
  • Intraperitoneal and intrathoracic surgery
  • Orthopedic surgery
  • Prostate surgery

Low risk* (reported risk of cardiac death or nonfatal MI generally less than 1 percent)

  • Ambulatory surgery
  • Endoscopic procedures
  • Superficial procedure
  • Cataract surgery
  • Breast surgery

* Do not generally require further preoperative cardiac testing.

It is relatively easy to remember these classes if you remember that the high risk surgeries are basically all the vascular surgeries except carotid endarterectomy and the low risk surgeries are basically all the outpatient/ambulatory procedures.

Step 4: Good functional capacity (MET level greater than or equal to 4) without symptoms?

1 MET is defined as 3.5 mL O2 uptake/kg per min, which is the resting oxygen uptake in a sitting position. Perioperative cardiac and long-term risk is increased in patients unable to meet a 4-MET demand during most normal daily activities.

Some questions which may help get at this:

  • What is your normal daily routine?
  • Do you do your own housework including vacuuming, carrying laundry, moving furniture? (4 or > METS)
  • Do you have stairs at home? Can you walk up a flight of stairs without chest pain or significant shortness of breath? (4 METS)
  • How far can you walk on a level without getting short of breath or having to rest?
  • Do you exercise? If so what type, how often, how far and how fast?

Step 5: NO or unknown functional capacity

Goldman in the mid 70’s developed a cardiac risk index for noncardiac surgerybased on 9 variables. Subsequently in the late 90’s this was revised into the Revised Goldman Cardiac Risk Index (2). Based on studying over 3800 patients and by validation in another 1400+ patients 6 predictors were found to increase cardiac risk. Of these 5 are now used in the ACC/AHA algorithm as “clinical risk factors.” (The other one was high risk surgery which is addressed earlier in the algorithm)

1. History of ischemic heart disease: MI, +Stress Test, Current “typical” chest pain,

Nitrate use, Q waves on EKG; do not count prior

Coronary revasc proc unless one of the other criteria

met

2. History of congestive heart failure: Pulmonary edema, PND, Bilateral rales, S3,

Pulmonary vascular redistribution on CXR.

3. History of cerebrovascular disease: TIA or stroke

4. Diabetes mellitus with preoperative treatment with insulin

5. Preoperative creatinine > 2.0 mg/dL

Risk of Major Cardiac Event (Cardiac death, MI, and nonfatal cardiac

arrest):

Risk Factors Risk

0 0.4%

1 0.9%

2 2.4%

3 + 5.4% (3)

CASE

You are called by the Neurosurgery Service to perform a preoperative evaluation of a 74 year old diabetic Navajo man with rheumatoid arthritis who sustained an atlantoaxial dislocation. The patient speaks little English, but the family informs you that he was in his usual state of health until he looked upwards several days ago and suddenly felt like his head was falling off.

At baseline, his activity is limited to ambulating slowly indoors, holding on to furniture. The family does not think he has experienced any chest discomfort, SOB, edema, orthopnea or PND. He sleeps on two pillows at night. He has not reported any fever, chills, or digestive disturbances, and they have not heard any cough.

PMH: RA MEDS: Glyburide 10 mg. daily NKDA

DM-II Enalapril 10 mg. daily

Htn Methotrexate 10 mg. weekly P/S: Resides with son

Mild Asthma Flomax 0.4 mg. daily Denies EtOH,tob

Remote CVA

EXAM: Thin elderly male. T 98.8 HR 96 R 18 BP 163/92

HEENT: Symmetric, anicteric, mucous membranes moist NECK: Unable to examine due to bulky brace extending to torso THORAX: Also limited, but CTA CV: RRR S1S2 w/o m/g/r

ABD: Scaphoid, NT, NABS< w/o HSM EXT: Bony deformities c/w longstanding RA, no C/C/E NEURO: Alert, moving all extremities, nonfocal.

LAB: Hgb.-11.6 WBC-6.7 Plt.-167 Na–129 K–4.8 Cl–99 HCO3 -20 BUN -40 Cr-2.4

Gluc. - 160

EKG: SR, 98, no diagnostic abnormality

PCXR: Poor quality due to overlying hardware and hypoinflation, but no gross abnormalities

QUESTIONS

1. According to the ACC/AHA guidelines what are the first two questions you should ask yourself in assessing the patient’s preoperative cardiac risk?

#- Does this patient need emergency noncardiac surgery?

$- Does this patient have any active cardiac conditions?

&- How many clinical risk factors does this patient have?

  1. # and $
  2. # and &
  3. $ and &

2. What is the patient’s procedure specific risk?

a. Low

b. Intermediate

c. High

3. The patient’s reported functional capacity corresponds with which class?

a. 1-3 METS

b. 4 METS

c. 5-10 METS

  1. How many clinical risk factors does the patient have and what are they?
  1. What will be your recommendation to the neurosurgeons regarding the patient and his cardiac risk?
  1. Proceed to surgery with no further interventions
  2. Proceed to surgery but first start patient on propranolol at 10mg po tid
  3. Proceed to surgery but first start patient on atenolol at 25mg daily, do not titirate
  4. Cancel surgery because patient’s risk is too high

Perioperative Beta Blockers:

Not for everyone! Risks outweigh benefits in low risk individuals.

POISE trial (4) randomized >8K patients undergoing noncardiac surgery to 100mg metoprolol before and after surgery, then 200mg daily after (high dose). Results showed improved cardiac outcomes but nullification of benefits due to increased mortality mainly due to increased stroke/hypotension.

Study by Lindauer et al. Retrospective study of >600K patients. Showed that patients who had a clinically significant decrease in mortality from perioperative beta blockers were those with a RCRI score of ≥3. Those who had a score of 2 had a small benefit. (Remember RCRI score are the clinical risk factors above.)

Should be used: : In current beta blocker users, or independent indications for their use

Beta blockers titrated to heart rate and blood pressure are probably recommended for patients undergoing vascular surgery who are at high cardiac risk owing to coronary artery disease or the finding of cardiac ischemia on preoperative

testing (4,5). (Level of Evidence: B)

2. Beta blockerstitrated to heart rate and blood pressure are probably recommended for patients in whom preoperative assessment for vascular surgery identifies high cardiac risk, as defined by the presence of more than 1 clinical risk factor.* (Level of Evidence: B)

3. Beta blockers titrated to heart rate and blood pressure are probably recommended for patients in whom preoperative assessment identifies coronary heart disease or highcardiac risk, as defined by the presence of more than 1 clinical risk factor,* who areundergoing intermediate-risk or vascular surgery. (Level of Evidence: B)

(AHA focused update perioperative beta blockers)

Beta 1 selective preferred—Atenolol, metoprolol, bisoprolol

Benefits closely linked to heart rate control. Titrate to goal HR = 60, avoid hypotension.(Circulation114:I344-9)

Ideally start 3 days preoperatively (weeks if possible). If necessary, can use Atenolol 5 mg IV/5min. in pre-op area; repeat after 10 min if tolerated to goal HR = 60.

Continue for at least one month postop

  1. One of the neurosurgery interns asks about need for stress testing in this patient. What do you tell him?

Answer: In most patients without active angina/mi and with intermediate risk semi-urgent surgery further cardiac testing almost never will change management.

Of note:

Stress Imaging:

Valuable in the management of high-risk outpatients(patients with 3 or more RCRI criteria or 1-2 RCRI criteria and poor functional status, hx CAD, or undergoing high risk surgery) since negative predictive value is excellent, but positive predictive value is poor. Thus, most useful in reassuring us when a patient thought to be at high risk is found to have a negative study.

Cardiac Catheterization/Revascularization:

Beneficial preoperatively only if otherwise indicated (in non-operative setting) – CARP trial(NEJM351:2795-2804).

Also careful selection of patients imperative as stopping anti-platelet agents for surgery may actually increase cardiac risk. (Drug eluting stent—cannot stop antiplatelet for 1 year, metal stent cannot stop for 4-6 weeks)

And finally

What else is useful in reducing perioperative cardiac risk?

Perioperative normothermia: Cardiac event rate 1.4% (vs. 6.3%) in patients kept warm in OR. (JAMA 277: 1127-34).

Clonidine: May be helpful in patients undergoing vasc surg but not enough evidence in patients undergoing noncardiac surgery (Wijeysundera, Am J Med, 2003)

Statins: ACC/AHA guidelines…for patients currently taking statin and scheduled for surgery, statins should be continued (level of evid B), statins should be considered in those undergoing vasc surg (B, probably should already be on for other indications) and for patients with 1 clinical risk factor and intermediate risk surgery, statins may be considered (evid C)

There is evidence in patients undergoing vascular surgery that statin withdrawl increases the frequency of cardiac events. (Schouten, Am J Cardiol 2007)

ASA : In a metanalysis, asa was shown to increase bleeding complications 1.5 fold but increase the frequency of ACS by 10%.. May want to consider continuing the asa for surgery only if bleeding may be associated with substantial death or disability (Burger, J Int Med, 2005)

Valvuloplasty? Valve stenting? In a few selected candidates

Detection for periop MI: It’s unclear which patients should be surveilled but recent study showed 11% 30 day mortality with poor monitoring and follow up. (Devereaux, Ann Int Med, 2011)

Post Module Evaluation

Please place completed evaluation in an interdepartmental mail envelope and address to Dr. Wendy Gerstein, Department of Medicine, VAMC (111).

1) Topic of module:______

2) On a scale of 1-5, how effective was this module for learning this topic? ______

(1= not effective at all, 5 = extremely effective)

3) Were there any obvious errors, confusing data, or omissions? Please list/comment below:

______

4) Was the attending involved in the teaching of this module? Yes/no (please circle).

5) Please provide any further comments/feedback about this module, or the inpatient curriculum in general:

______

6) Please circle one:

Attending Resident (R2/R3)Intern Medical student