Basic principles of assessing cardiac risk in patients undergoing noncardiac surgery. Audience: general internists and family practitioners. Watch my YouTube video describing these slides: http://youtu.be/AAGgwU0uXj0
In this PowerPoint presentation I review the general approach to preoperative cardiac risk assessment.
The recommendations made in this presentation are directed towards patients 50 yrs of age and older undergoing noncardiac surgery. The age of 50 is chosen because this is who guidelines are focused on and who was enrolled in studies to develop and validate the revised cardiac risk index.
If patients have new or unstable cardiac symptoms those should be evaluated according to current guidelines. They should not undergo further cardiac preop assessment until those issues are resolved.
Cardiac risk assessment in the has 3 goals: 1) to assess cardiac risk, 2) to determine the need for changes in management to reduce that risk as much as possible, and 3) identify cardiovascular conditions or risk factors that require longer-term management beyond the perioperative period.
The history and PE are the cornerstones of cardiac risk assessment. Cardiac testing has a very limited role (see PowerPoints on this topic)
The most important tool for cardiac risk assessment is a good cardiac history. These are the elements that should be the focus of that history: Detection of serious cardiac conditions [unstable or new cardiac conditions (like recent MI, unstable angina), decompensated CHF, significant arrhythmias (high grade av block, SVT, symptomatic bradycardia, V tach), severe valvular disease (esp aortic stenosis)] Evaluation of the stability of CAD (any recent testing, recent MI, recent revascularization?) Assessment of comorbidities known to influence perioperative cardiac outcomes- these are what is contained in the RCRI or the Gupta tool. Appraisal of functional capacity (see next slide) Cardiac medications- will need to decide if they need adjustment to optimize cardiac conditions prior to surgery or if they need to be held during the perioperative period.
Patients with reduced functional capacity are at increased risk of complications. This table shows how much metabolic equivalents (or METs) various activities are worth. 4 METs is the magic cutoff. If patients can achieve 4 METs of activity (climbing 2 flights of stairs or jogging at a moderate pace) without difficulty they can proceed to surgery with low anticipated risk of cardiac complications.
The physical exam has a similar function to the history- to detect presence of and control of cardiac conditions. The heart and all vascular territories (carotids, jugular veins, abdominal aorta, and peripheral vasculature) should be evaluated. Pay close attention to aortic auscultation to detect aortic stenosis. In CHF patients listen and look for S3, peripheral edema, elevated JVP, crackles). Peripheral vascular examination is needed to detect occult CAD (remember up to 75% of patients with PVD have CAD).
After the H&P you plug the information into one of the risk prediction tools yielding your patient’s predicted risk of cardiac complications from the planned surgery. Then you decide if any further testing is needed or if any interventions can further reduce risk. This risk should be discussed with both the patient and the surgeons. Ultimately the surgeon and the patient will decide whether or not the benefits of the surgery outweigh the risks.
Alternatively you could evaluate the patient following the diagram on the last slide.
This is a somewhat controversial question. Both right bundle branch block (upper ECG) and left bundle branch block (lower ECG) have been associated with perioperative MI. LBBB has also been associated with perioperative mortality. BUT as was shown in the study published in the Annals of Surgery in 2007 no ECG abnormality provided additional predictive value over risk indices in multivariate analysis (ie it adds nothing to the RCRI).
The 2014 ACC preop guidelines state than an ECG is reasonable in patients with known CAD, PAD or cerebrovascular disease, significant arrhythmia, or other structural heart disease undergoing intermediate or high risk surgery. [Class IIa recommendation (benefit outweighs risk but the data is limited)]. Routine ECG is not useful in asymptomatic patients undergoing low risk surgical procedures [Class III recommendation (no benefit but data is limited)].
A baseline ECG could be useful to assess changes in the postoperative period. If an ECG has been obtained in the previous 1-3 months another ECG is not needed.
This is the 2014 ACC/AHA stepwise approach to perioperative cardiac risk assessment. Steps 1 and 2 assess whether the patient needs emergent surgery (in most cases the patient will go to surgery) and if the patient is experiencing an acute coronary syndrome (if so they should not go to surgery and treatment of the ACS should follow guidelines based therapy).
In step 3 you should use the RCRI or the Gupta tool and determine the patient’s risk for MACE. They will either be at low risk or at elevated risk. Further management and evaluation of patients at elevated risk is the subject of another presentation.
Overview of preoperative cardiac risk assessment
Overview of Preoperative Cardiac Risk
Assessment for the General Internist
Terry Shaneyfelt, MD, MPH
Associate Professor, UAB Department of Medicine
• Adult patients, 50 yrs of age or older, undergoing
• Unstable or new cardiac symptoms should be
evaluated according to current guidelines
Cardiac Risk Assessment
1. Assess cardiac risk of planned surgical procedure
2. Determine the need for changes in management
3. Identification of cardiovascular conditions or risk
factors requiring longer-term management
• 3 components:
• Physical exam
• Cardiac Testing
Take a good cardiac HISTORY
Evaluation of the
stability of known CAD