What tests should you consider for a patient heading to surgery?
ACC on preop EKG in guideline text:
- reasonable for patients with known coronary heart disease, significant arrhythmias, peripheral artery disease, cerebrovascular disease, or other significant structural heart disease, or signs/symptoms suggestive of potential CVD undergoing elevated-risk surgery, a preoperative resting 12-lead electrocardiogram (ECG) is reasonable to establish a preop baseline and guide perioperative mgmt (2a, B)
- may be considered for asymptomatic patients without known cardiovascular disease undergoing elevated risk surgeries to establish a baseline and guide perioperative mgmt (2b,B)
- not useful for asymptomatic patients undergoing low risk surgical procedures (III:NB, B)
- when a preoperative EKG exhibits new abnormalities, further evaluation is reasonable to refine assessment of cardiovascular risk (2a, B)
ACC on EKG from algorithm flowchart:
- when risk modifiers are present, EKG is reasonable in patients with established CVD or symptoms (2a)
- when risk of MACE is elevated but no risk modifiers are present, EKG can be considered in asymptomatic patients without CVD (2b)
Timing of EKG: ACC notes that the optimal time interval between preop EKG and non-cardiac surgery is unknown. Previous ACC guidelines have suggested an EKG within 1-3 months of surgery in a stable patient is reasonable.
ACC also cautions you not to overestimate the value of preop EKGIs. Although EKG's reveal a variety of information about the patient, that information is often already known and evident from risk assessment tools, rarely adding new insight. Findings of importance are not well defined, but ones the ACC ventures to say are significant include significant Q-waves, LV hypertrophy, ST-segment elevation, ST depression, T-wave inversion, Mobitz type II or higher block, bundle branch blocks, AF, or QT interval prolongation.
ACC on preop eval of LV function:
- recommended for patients with dyspnea of unknown origin, exam findings of HF, or suspected new/worsening ventricular dysfunction (1, B)
- reasonable for patients with HF with worsening dyspnea or other change in clinical status (2a, C)
- routine preop eval of LV function is not recommended in clinically stable asymptomatic patients (3, B)
ACC on preop eval of RV function:
- several conditions (MR, TR, PH) are mentioned in the ACC guideline which are commonly evaluated with echo for RV fxn, but no recommendation is given on obtaining echo evaluation; the only recommendation given is phrased in the negative as follows...
- routine eval of RV fxn in stable, clinically asymptomatic patients is not recommended
ACC on preop eval of valve dz:
- recommended for patients with clinically suspected moderate or greater degrees of valvular stenosis or regurgitation if there has been either (1) no prior echo within 1 year, or (2) a significant change in clinical status or physical exam since last eval (l, C)
These recommendations endorse a limited role for preop echocardiography. They apply mostly to those with symptoms, severe disease, or both. They are mostly permissive, luke-warm recommendations. The recommendation against routine echo continues. And the evidence does not support clear benefit. The retrospective cohort study (Wijeysundera BMJ 2011, see ref) of 9 years of patients undergoing intermediate to high risk surgery in Ontario hospitals compared 40,000 patients with preop echo to 70,000 propensity-score matched controls (always a tricky study design) without echo. Preop echo was not associated with improved survival or shorter hospital stay.
ICSI says consider checking K+ if:
- Patient takes Digoxin, diuretics, ACE inhibitor, or ARB
- check electrolytes for those on lithium
ASA's 2012 guideline mentions testing directed by clinical characteristics including likely perioperative therapies, endocrine disorders, risk of renal and liver dysfunction, and use of certain medications or alternative therapies. ASA's Choosing Wisely document recommends no preop CBC, BMP or CMP, or coags in patients without significant systemic disease (ASA class I or II) undergoing low-risk
surgery when blood loss (or fluid shifts) is/are expected to be minimal.
Do not perform routine preop CXR.
Consider preop CXR if patient has signs or symptoms suggesting new or unstable cardiopulmonary disease.
Not only does the ESA (gr B) guideline review the evidence of no benefit, but 4 different organizations have identified preop CXR as a practice to be discontinued in the Choosing Wisely campaign, namely the American College of Physicians, the American College of Radiology, the American College of Surgeons, and the Society of General Internal Medicine, each offering their own review of the evidence.
ASA states that extremes of age, smoking, stable COPD, stable cardiac disease, or resolved recent upper respiratory infection should not be considered unequivocal indications for chest radiography.
ICSI says routine Hgb/CBC not indicated (strong, low), consider based upon patient's underlying medical condition and the planned procedure (e.g. pt has history of anemia or history suggesting recent blood loss or anemia).
ASA says routine Hgb/CBC not indicated, consider based upon type and invasiveness of procedure, patients with liver disease, extremes of age, and history of anemia, bleeding, and other hematologic disorders.
ESA says:
- Routine coagulation tests not recommended unless there are specific risk factors in the history (D).
- If coag disorder suspected, patient should be referred to a hematologist (D).
ICSI says coagulation studies are not routinely necessary unless a specific indication is present
Preoperative diagnostic spirometry in non- cardiothoracic surgery patients cannot be recommended to evaluate the risk of postoperative complications (ESA D).
Spirometry characterizes obstructive lung disease well, but it does not well predict post-operative complications nor guide demonstrated management improvements.
ASA says routine urinalysis is not indicated except for specific procedures (e.g., prosthesis implantation, urologic procedures) or when urinary tract symptoms are present.
In 2017 the Canadian Cardiovascular Society guideline (see ref) recommended pre- operative BNP (or NT-proBNP) and post- operative Troponin on certain (high-risk) patients. The European Society of Cardiology included recommendations on BNP & Troponin biomarkers in 2022 as well. The ACC-AHA guideline of 2024 finally addresses this as well with a permissive but far from directive stance.
ACC agrees that elevations in these biomarkers do denote patients who are subject to worse perioperative outcomes including mortality. Preop ACC recommendations are:
- reasonable to check preop BNP or NT- proBNP In patients with known CVD, or age 2 65 years, or age 45 years with symptoms suggestive of CVD undergoing elevated-risk surgery to supplement evaluation of perioperative risk (2a, B)
- can be considered to check preop cardiac troponin in patients with known CVD, or age 2 65 years, or age 2 45 years with symptoms suggestive of CVD undergoing elevated-risk surgery to supplement evaluation of perioperative risk (2b, B)
ACC gives a lot of caveats. First and most importantly, no one knows how to use these results in any protocol to improve outcomes. Do we monitor these patients differently post- op? Do we treat them pre-emptively in some fashion before, during, or after surgery? No one knows at least yet as no studies as of yet show how to use this information profitably for the patient's benefit. Second, no one knows optimal thresholds for biomarkers to trigger concern or mgmt changes. Third, there have been no evaluations of these biomarkers in low-risk surgical patient populations.
Post-op ACC recommendations are:
- can be considered to check post-op troponin 24 and 48 hours after surgery in patients with known CVD, symptoms of CVD, or age 65 years with cardiovascular risk factors undergoing elevated-risk surgery to identify myocardial injury (2b, B)
- do not check routine screening post-op troponin in patients undergoing low-risk surgery without signs or symptoms suggestive of myocardial ischemia or MI (3, B)
Post-operative troponin testing is part of the ACC's larger attention to MINS, or myocardial injury after non-cardiac surgery. The ACC has an entire separate scientific statement on MINS.
Note that if signs or symptoms of myocardial ischemia or heart failure develop, then diagnostic testing with there biomarkers and any clinically indicated evaluation is quite appropriate (and explicitly endorsed by ACC).
Various
authorities have opinions about the value of additional pre-op tests.
For instance, beta-HCG in reproductive-age women with uncertain
pregnancy status, BUN & Creat in patients with suspected or
known renal disease, etc.
Most importantly, if your knowledge of
the patient suggest risk of deranged lytes, renal fxn, pulmonary fxn,
etc., and it bears on surgery, you are justified to check any test.
No routine preop testing is indicated.
A Cochrane systematic review of 2012 looked specifically at the value of preop testing before cataract surgery, finding 3 RCT's of 21,531 total patients. Patients undergoing cataract surgery did have occasional adverse medical events associated with surgery (3.2% of the time), which is not surprising since patients with cataracts often have numerous other medical comorbidities. However, those rare complications occurred at (precisely!) equal rates (354 vs. 353) whether patients were randomized to routine preop testing or no testing. Routine preop testing and responding to any findings did not reduce those adverse events during or after surgery. The conclusion is that routine preop testing does not improve the safety of cataract surgery.