Flashcards in CV Assessment Deck (92):
Steps of the cardiac assessment
1) Determine the urgency of surgery
2) Determine if the patient has an active cardiac condition
3) Determine surgical risk (risk that the surgery will further damage the heart)
4) Assess functional capacity (exercise tolerance, etc)
5) Assess clinical predictors/markers
What is the goal of the pre-op cardiac assessment?
To identify patients with heart disease who are at high risk for perioperative morbidity or mortality or those with modifiable conditions or risks
Minor clinical predictors of increased CV risk
>75 years old
Low exercise tolerance
History of CVA
Rhythm other than NSR
Intermediate clinical predictors of increased CV risk
Prior MI (OVER one month ago) and Q waves on EKG
Mild, stable angina
Compensated or previous LV failure/CHF
DM (both insulin dependent AND non-insulin dependent)
Chronic renal insufficiency (CR > 2.0)
MAJOR clinical predictors of increased CV risk
These are major, current cardiac conditions
- Unstable coronary syndromes (active ischmia on EKG)
- MI within the last month
- Severe or unstable angina
- Decompensated CHF
- Significant arrhythmias (arrhythmias that are symptomatic)
- Severe valvular disease
What valvular disease are we most concerned about when it comes to intraoperative management?
Special considerations for cardiac assessment of Emily Rucker
She is a heartless creature, and therefore does not require a pre-op cardiac assessment.
What is the overall mortality risk of acute MI for the average person receiving GA?
The risk increases if the patient is undergoing intra-thoracic or intra-abdominal surgery or for surgeries lasting longer than 3 hours
Risk of periop reinfarction for those with history of prior acute MI
> 6 months ago = 6%
3-6 months ago = 15%
Within 3 months = 30%
Highest risk is within 30 days after acute MI
Mortality rate for perioperative reinfarction
ACC/AHA guidelines suggest waiting AT LEAST _______ post-MI before having elective surgery
This also allows us time to identify which areas of the myocardium will be most at risk during surgery
Surgeries with high risk of cardiac morbidity/mortality (>5% additional risk)
Aortic surgery (or surgery on other major vasculature)
Peripheral vascular surgery
Major emergent operations (especially for the elderly)
Prolonged procedures with major fluid shift/blood losses
Surgeries with intermediate risk of cardiac morbidity/mortality (1-5% additional risk)
Head and neck
Major neuro / ortho cases
Endovascular aneurysm repair
Surgeries with low risk of cardiac morbidity/mortality (<1% additional risk)
Basic components of the cardiac assessment
Patient history (and medication history)
Resting 12-lead EKG (only if indicated!!)
Who is indicated for a pre-op 12-lead EKG?
Patients with clinical indicators of CV disease
A 12-lead, if needed, should be done within ____days of surgery
Adjunct testing that can be done for a cardiac assessment
What is the gold standard for visualizing coronary anatomy?
Why is taking a good cardiac history important?
Because most of the time, history can diagnose if someone is at risk for cardiac events intra-op.
Patients with this type of angina are at a much higher risk of a cardiac event
What do we want to know about a patient's angina?
What are the precipitating factors?
How often does it occur? Duration of the pain? What relieves it (rest, medication, etc)?
What is the difference between stable and unstable angina?
Stable is predictable. Usually occurs during exercise or stress.
Unstable is unpredictable. May happen at rest or with light activity. It is a major predictor that an MI may occur soon.
Why is estrogen status of a female important to the CV history?
Estrogen has a protective factor against CV disease. Post-menopausal women are therefore at higher risk of a periop event.
In the absence of lung disease, this is the most striking evidence of decreased cardiac reserve
decreased exercise tolerance
What is the duke activity status index?
A questionnaire that is able to measure functional capacity (exercise tolerance) and how much O2 demand the heart is able to tolerate
Findings of the Duke Activity Status Index and what they mean
1-4 METS (eating, dressing, walking around the house, dishwashing)
4-10 METS (climbing stairs, walking around the neighborhood, heavy housework, golfing, bowling, dancing)
>10 METS (strenuous sports such as swimming, tennis, running, football, basketball, etc)
Patients unable to meet a 4-MET demand are at higher cardiac risk
Patients with this disorder may experience angina despite having healthy coronaries
A spasm of this can result in angina-like pain that is also relieved by NTG
____% of ischemic episodes in CAD occur without associated angina (are silent)
____% of acute MIs are silent
What is Prinzmetal's Angina?
Angina that occurs at rest due to coronary vasospasm.
In 85% of cases, there is a fixed, proximal lesion in a major artery
In 15% of cases, there is only spasm with no associated lesion.
Can Prinzmeta's angina cause heart damage?
Patients with Prinzmetal's angina also tend to have higher incidence of
Migraines and raynaud's disease
What do you want to know about a patient's pacemaker / ICD?
Indication for insertion
Underlying heart rhythm
Type of pacemaker (demand, fixed, or radiofrequency)
The chamber paced and the chamber sensed
Effect of a magnet
Current settings and battery life
Make sure an electrophysiologist checks out the pacer/ICD
When should a patient's pacemaker/ICD be evaluated before surgery?
3-6 months before surgery
When should the ICD be deactivated?
The day of surgery
Why should the ICD be deactivated before surgery?
The ICD may detect electrical equipment of the OR as an arrhythmia and then discharge. For this reason, we turn off the ICD and place pads on the patient.
Are pacemakers usually on a synchronous or non-synchronous mode?
What should we have immediately available for patients with pacemakers?
A magnet. Most pacers can be converted to a fixed rate (asynchronous mode) by placing a magnet over the pacemaker box.
We should also have external pacing pads available.
Where should grounding pads be placed in a patient with a pacer/ICD?
As far away from the pulse generator as possible
Type of electrocautery that should be used is patients with a pacer/ICD?
Bipolar (as opposed to monopolar). Bipolar decreases the amount of electricity flowing through the patient.
Where is Erb's point?
Third intercostal space at the left sternal border. S2 is best auscultated here.
Why do we listen to the lungs in CV assessment?
Window to the LV. CHF can cause rales, SOB, dyspnea, etc.
HTN is defined as a BP reading over
When do we treat HTN?
When SBP is >160 and DBP is >90.
What do we want to give patient with uncontrolled hypertension before surgery?
Give a beta blocker. These may have a protective benefit.
What do you do if a patient comes for surgery with long-standing severe HTN or uncontrolled HTN?
May need to delay surgery to get BP under control. Get an EKG and serum CR/BUN to look for disease states that go with chronic HTN.
If a patient is on diuretics for HTN, what test should you get prior to surgery?
Recommendation regarding beta blockers for those undergoing vascular surgery
Start beta blocker therapy 1 month prior to surgery. Starting the day of can increase risk of stroke.
Discontinuing beta blocker therapy before surgery can cause
increase risk of periop CV morbidity
What is orthopnea?
Dyspnea that occurs as a result of lying flat. It occurs in CHF because the supine position causes more blood to enter the central circulation, increasing pulmonary capillary pressure. And now you know!
Heart failure can be defined as
abnormal contractility or relaxation of the heart
HF can be caused by
HTN or ischemic heart disease
Seeing this on EKG raises your suspicion of heart failure
The following clinical findings would make you suspicious that your patient has heart failure
3rd or 4th heart sounds
LVH on EKG
What should you do if your patient has come for elective surgery and has decompensated HF/LV function?
Postpone the surgery
Work-up for a patient with HF
BNP (marker of how progressed the CHF is. Ideal level is <100)
CXR (if pulmonary edema suspected)
Echo (to measure EF)
Should cardiac medications be continued for surgery?
Yes! Even anticoagulants if surgery is able to tolerate it.
Severe aortic stenosis poses the greatest risk if valve area is less than
1 cm2. If the patient has symptoms, postpone the surgery.
These types of murmurs are always pathologic and require further intervention
Considerations for a patient with a prosthetic heart valve
May need to bridge anticoagulant therapy (may need to stop coumadin a week prior or can be placed on a heparin drip that can be stopped 6 hours prior to surgery)
May need subacute bacterial endocarditis prophylaxis (SBE prophylaxis)
These arrhythmias carry the highest perioperative risk
SVT and ventricular arrhythmias
This block is highly associated with CAD
LBBB. If this is a new block for the patient, stress testing or consultation is needed.
Postpone a surgery for these arrhythmias
New or uncontrolled a-fib
High-grade or complete HB
These are the 3 most common cardiac meds you will see
When should antiplatelets (ASA/plavix) be discontinued?
7-10 days prior to sx
When should anticoagulents (coumadin/LMWH) be discontinued?
3-5 days prior to sx for Coumadin (want INR < 1.5)
12 hours prior to sx for LMWH
When should fibrinolytics (tPA, streptokinase, urokinase) be discontinued?
We usually cannot discontinue these
When should we order a CXR?
History of CHF
Symptomatic CV disease
Older than 75
Indications for a 12 lead EKG
1) Patients with known CVD, CAD, PVD having intermediate to high risk surgery
2) Patients with at least one clinical risk factor for having vascular surgery (HTN, advanced age, low exercise tolerance, hx of CVA, known arrhythmia)
We MIGHT want to get an EKG with these patients
1) Having vascular surgery, but no clinical risk factors
2) Having at least one clinical risk factor and having intermediate or high risk surgery
Lab tests you may want to consider related to comorbidities
Purpose of a treadmill stress test
Stimulate the SNS to increase HR and BP, thereby increasing O2 demand to look for ischemic changes on EKG. We are also making sure that the HR increases appropriately and that BP doesn't rise too much.
Information we will receive from a treadmill stress test
Duration of exercise the patient can tolerate
Max HR achieved
Time of onset of ST depression
Degree of ST depression
Time until resolution of ST
These results on a treadmill stress test will result in a positive test (indicating presence of CAD)
- ST depression > 2.5cm
- ST depression occurs within 3 minutes of exercise
- Serious ventricular arrhythmias
- Prolonged recovery of ST change
- If BP or HR increase during ST-depression
- If hypotension occurs (ominous sign)
Medications given for pharm stress testing
Dobutamine (B1 activity- pharm shout-out, Hollaaaa!) and adenosine or dipyridamole.
Who would we give a pharm stress test to?
Those unable to exercise
Process of pharm stress testing
Overall, we are looking for ischemia via perfusion imaging, not EKG. To do this, we give meds that will vasodilate the coronary arteries (diseased arteries are less able to dilate) and increase demand demand on the heart. We also give a gamma-emitting dye (thallium) that allows us to image the blood within the heart and lungs.
Areas with decreased perfusion (cold spots) only during times of stress shows ischemia. Spots that have a constant perfusion deficit are suggestive of an old MI. Areas of redistribution deficits are at higher risk of ischemia and infarction.
When would we request stress testing?
1) Active cardiac condition
- Unstable coronary syndromes
- Unstable o severe angina
- Recent MI
- Decompensated HF
- Significant dysrhythmias
- Severe valvular disease
2) Three or more risk factors and poor functional capacity undergoing vascular surgery
3) MAYBE get it if
- At least 1-2 risk factors and poor functional capacity having intermediate risk surgery if it will change management
- At least 1-2 risk factors and good functional capacity, but having vascular surgery
What are you looking for during a stress echo?
Regional abnormalities in wall motion during stress (infusion of dobutamine). This test is highly predictive of adverse cardiac events.
When do we order a pre-op echo?
1) Current of prior HF (with worsening dyspnea or other change in clinical status)
2) Dyspnea of unknown origin
3) Possible aortic stenosis
This is a gold-standard test for someone undergoing cardiac surgery
When should a patient have a pre-op cath?
1) Stable angina with left main CAD
2) Stable angina with 3 vessel disease
3) Stable angina 2-vessel disease with significant LAD lesion and EF <50% or demonstrable ischemia on noninvasive stress testing
4) High-risk unstabile angina or non-STEMI
5) Acute STEMI
Need to wait _____days after balloon angioplasty before a patient can be taken off anticoagulants for another surgery
At least 14 days
Need to wait _____days after bare-metal stent placement before a patient can be taken off anticoagulants for another surgery
At least 30-45 days
Need to wait _____days after drug-eluting stent placement before a patient can be taken off anticoagulants for another surgery
At least 365 days
MRI can be very sensitive to detecting infarctions when using this dye
Cardiac conditions placing a patient at high risk for SBE
Prosthetic heart valves
History of infective endocarditis
Unrepaired cyanotic congenital heart disease
Repaired congenital heart disease with residual effects
Cardiac transplant recipients with cardiac valvular disease
For patients with high SBE risk, patients undergoing these surgeries should receive SBE prophylaxis
Dental and respiratory surgeries
SBE prophylaxis is not recommended with these surgeries