CV Assessment Flashcards
What are the 5 steps of the cardiac pre-op assessment?
- Urgency of surgery
- Determine if active cardiac condition
- Determine surgical risk
- Assess functional capacity
- Assess clinical predictors/markers
What are some MINOR clinical predictors of increased cardiac risks?
- Uncontrolled HTN
- Abnormal ECG
- Low functional capacity
- Rhythm other than sinus rhythm
What are some INTERMEDIATE clinical predictors of increased cardiac risk?
- Known CAD
- Prior MI > 1 month and Q waves on ECG
- History of mild, stable angina
- Compensated or previous LV failure/CHF
- Diabetes
- Chronic renal insufficiency (CR > 2.0mg/dL)
- Cerebrovascular disease (stroke, TIA)
What are some MAJOR clinical predictors of increased cardiac risk? (active cardiac conditions)
- Unstable coronary syndromes
- Acute or recent MI < 1 month
- Unstable or severe angina
- Decompensated CHF
- Significant arrhythmias
- Severe valvular disease
What is the overall mortality risk of acute MI after GA and what increases this risk?
0.3%, increased with intra-thoracic or intra-abdominal surgery or surgery lasting longer than 3 hours.
What is the mortality risk of acute MI after GA if the pt has a history of a prior MI? What is the mortality rate if reinfarction occurs?
- If the MI was greater than 6 months ago, the incidence is 6%
- If the MI was 3-6 months ago, the incidence is 10%
- If the MI was within 3 months, the incidence is 30%
- If reinfarction occurs the mortality rate is 50%
When is the highest risk period for reinfarction during GA? How long do ACC/AHA guidelines recommend waiting post MI before elective surgery?
Highest risk period is within 30 days after acute MI. The ACC/AHA guidelines recommend waiting at least 4-6 weeks post MI before elective surgery.
What surgeries are considered high risk for MI?
- Intraperitoneal
- Intrathoracic
- Aortic surgery/other major vascular surgery
- Emergent major operations (especially in the elderly)
- Prolonged procedures with large fluid shifts/blood loss
What surgeries are considered to be intermediate risk for MI?
- Carotid endarterectomy
- Peripheral vascular surgery
- Head and neck
- Neurologic/orthopedic
- Endovascular aneurysm repair
What are some CV adjunct tests that can be performed?
- Chest x-ray
- Labs
- Stress testing
- Echocardiography
- MRI
- CAT scan
- Coronary angiography (gold standard for coronary anatomy)
What are some questions to ask during the CV history?
- Do you have shortness of breath lying flat (orthopnea)?
- Do you have shortness of breath with exertion?
- Do you have congestive heart failure?
- Do you have a history of a heart attack?
- Do you have angina with activity or at rest? Chest pain/pressure/tightness related to your heart? What are the precipitating factors, associated symptoms, frequency, duration and methods of relief?
- Do you have an irregular heartbeat or palpitations?
- Do you have a pacemaker or ICD?
- Do you have a heart murmur?
- Have you had any previous diagnostic tests or therapies?
- Who is your treating physician(s)?
- Do you have problems with blood pressure or HTN?
- Do you have PVD?
- Do you have a history of TIA/CVA?
- Do you have diabetes?
- Renal insufficency?
- High cholesterol?
- Estrogen status?
- Age and weight?
- Fatigued?
- Syncope?
- Anemia?
- Smoke or drink alcohol?
- Illicit drug use?
What is the most striking evidence of decreased cardiac reserve?
Exercise tolerance in absence of significant lung disease.
Describe the levels of the Duke Activity Status Index.
1-4 METS: eating, dressing, walking around the house, dishwashing
4-10 METS: climbing stairs, walking in the neighborhood, heavy housework, golfing, bowling dancing
> 10 METS: strenuous sports
Patients unable to meet a 4 MET demand are considered to be at higher risk
What percent of ischemic episodes in CAD occur without angina?
80%
What percent of acute MIs are silent?
10-15%
What is Prinzmetal’s angina?
Vasospastic angina that occurs at rest.
What percent of patients with Prinzmetal’s angina have a fixed proximal lesion in a major artery?
85%, 15% just have spasm.
What other disorders to patients with Prinzmetals angina have a higher incidence of?
Migraine headaches and Raynaud’s.
What things should you know about a patient with a pacemaker/ICD?
- Indication for the pacemaker/ICD?
- Underlying rhythm and rate
- The type of pacemaker, the chamber paced, and the chamber sensed
- Have the pacemaker or defibrillator interrogated, noting current settings and battery life
- Evaluate effect of magnet
- Inactive ICD tachyarrhythmia detection and put defibrillator pads on
- Device should be evaluated within 3-6 months before surgery
What precautions should be taken for a patient with a pacemaker/ICD?
- Electromagnetic interference can occur with electrocautery, which can inhibit pacemaker firing
- Have a magnet immediately available: most pacemakers can be converted to a fixed rate by placing a magnet over the pacemaker box
- Grounding pads should be as far from the pulse generator and leads as possible
- Bipolar electrocautery is preferred; avoid monopolar
- Monitor some form of blood flow (pulse ox, intra-arterial BP measurement)
- Have external pacing available.
What is involved in the physical CV exam?
Overall appearance: obesity, SOB, sternal incision, pacemaker box
Heart: Heart sounds/murmurs
Neck: JVD, Carotid bruit
Lungs: Lung sounds, SOB, effort
Vital signs: BP in both arms
Extremities: peripheral edema, pulses, clubbing, skin color
How is hypertension defined?
BP readings greater than 140/90
When should HTN be treated?
When SBP >160 and diastolic >90
What drugs may have a protective benefit for HTN patients?
Beta blockers
What are risk factors of HTN?
- Major risk factor for cardiovascular mortality
- Increases incidence of stroke, CHF, MI and progression to renal insufficiency and malignant hypertension
What interventions should be taken for a pre-op patient with hypertension?
- May need to delay surgery
- Need ECG and CR/BUN
- If on diuretics get a chem 7
- Continue meds
- Anxiolytics
What are the ACC/AHA recommendations for beta blocker therapy perioperatively?
- Continue beta blocker therapy because discontinuation may increase perioperative CV morbitiy
- Give beta blockers to high risk patients having vascular surgery
Describe heart failure.
Abnormal contractility or abnormal relaxation of the heart muscle
What are some causes of heart failure?
HTN, IHD.
What are some symptoms of heart failure?
- Orthopnea
- Nocturnal coughing
- Fatigue
- Peripheral edema
- 3rd/4th heart sounds
- Resting tachycardia
- Rales
- JVD
- Ascites
- LVH on ECG
When should surgery be postponed for a patient with heart failure?
-Decompensated heart failure or left ventricle function is high risk and elective surgery should be postponed
What tests should be ordered for patients with HF?
- ECG
- Chem 7
- BUN/CR
- BNP <100pg/mL
- CXR if suspected pulmonary edema
- Echo to measure LVEF
What should be done for a patient with a valvular abnormality?
- Identify the type of valvular lesion
- Evaluate clinical symptoms and testing data
- Severe aortic stenosis poses the greatest risk if the valve area is less than 1cm2
- If they are symptomatic you may want to postpone surgery
- Diastolic murmurs are always pathologic and require further evaluation
- If the patient has a prosthetic heart valve you may need to bridge anticoagulant therapy and may need subacute bacterial endocarditis prophylaxis
How should you manage a patient with arrhythmias?
- SVT and ventricular arrhythmias are associated with perioperative risk
- LBBB is strongly associated with coronary artery disease
- If new LBBB stress testing or consultation is needed
When should you postpone surgery for patients with arrhythmias?
- Uncontrolled or new onset a fib
- Ventricular tachycardia
- Symptomatic bradycardia
- High-grade or third degree HB
What are some common medications that cardiac patients may be on?
- Beta blockers
- Statins
- Aspirin
- Ace inhibitors/ARBs
- Calcium channel blockers
- Nitro
- Diuretics
- Antiarrhythmics
When should Aspirin and Plavix be discontinued prior to surgery?
7-10 days prior
When should coumadin be discontinued before surgery and what should the INR be before surgery?
Discontinue 3-5 days, INR <1.5
When should LMWH be discontinued before surgery?
12 hours prior
When should you order a chest x-ray before surgery?
- Pt is over 75 years old
- History of CHF
- Symptomatic cardiovascular disease
What pathologies can you see with a chest x-ray?
- Cardiomegaly
- Pulmonary vascular congestion/pulmonary edema
- Pleural effusions
When should a pre-op ECG be ordered?
- At least 1 clinical risk factor having vascular surgery
- CAD, PAD, CVD having intermediate or high risk surgery
- Maybe if no clinical risk but vascular surgery or at least 1 clinical risk factor having intermediate or high risk surgery
- Do not get on asymptomatic patients and low risk surgery
What should the pre-op ECG be reviewed for?
- Acute myocardial ischemia
- Prior myocardial infarction
- Rhythm or conduction disturbances
- Cardiomegaly or ventricular hypertrophy
- Other abnormalities/electrolyte imbalances
What are the 5 principle indicators of ischemia on an ECG?
- ST segment elevation greater than 1 mm
- ST segment depression, flat or downslope of greater than 1mm
- T wave inversion
- Peaked T waves
- Development of Q waves
What are the inferior leads and what artery supplies this area of the heart?
- AVF, II, III
- RCA
What are the posterior leads and what artery supplies this area of the heart?
- V1, V2, V3
- RCA
What are the antero-septal leads and what artery supplies this area of the heart?
- V1, V2, V3, V4
- LAD
What are the lateral leads and what artery supplies this area of the heart?
- I, AVL, V5, V6
- Circumflex branch of LCA
When should a pre-op ECG be performed?
Within 30 days of surgery
What lab data could be useful for the cardiac patient?
- K+
- BUN/Cr
- ABGs
- Hgb/Hct
- INR/PT
Describe treadmill stress testing.
-Simulates sympathetic nervous system stimulation by increasing BP and HR and therefor increasing myocardial O2 demand and consumption.
What is looked for with treadmill stress testing and what is it interpreted based on?
- Look for ischemia by ECG changes
- Interpreted based on:
- Duration of exercise the patient can perform
- Max HR achieved
- Time of onset of ST depression
- Degree of ST depressoin
- Time until resolution of the ST segment
What ECG criteria and non-ECG responses indicate a positive treadmill stress test?
ECG criteria:
-ST-segment depression>2.5mm
-ST-depression occurring in first 3 minutes of test
-Serious ventricular arrhythmias
-Prolonged duration of ST depression in post recovery period
Non-ECG criteria:
-If increase in BP or HR occurs at time of ST depression
-If hypotension occurs it is an ominous sign
Describe pharmacologic stress testing and what patients it is used on.
- Useful in patients unable to exercise
- Looks for ischemia by perfusion imaging, not ECG changes
- IV injection of thallium that permits the imaging of blood within the heart and lungs
- Dipyridamole or adenosine administered as a vasodilator to increase coronary blood flow
- The are of decreased perfusion only during stress shows ischemia, whereas a constant perfusion defect suggests old MI
- Areas of redistribution defects are at higher risk of ischemia and infactrion
When do you request cardiac stress testing?
-Active cardiac conditions (unstable coronary syndromes, unstable or severe angina, reent MI, decompensated HF, significant arrhythmias, severe valvular disease)
-3 or more clinical risk factors and poor functional capacity having vascular surgery
-Maybe if:
~At least 1-2 clinical risk factors and poor functional capacity having intermediate risk surgery if it will change management
~At least 1-2 clinical risk factors and good functional capacity having vascular surgery
What can be determined from an echocardiogram?
- Measurement of the dimensions of cardiac chambers and vessels and the thickness of the myocardium
- Global ventricular systolic function: EF
- Regional wall motion abnormalities
- Valve structure and motion
- Can detect blood flow and measure gradients
- Chamber enlargement
- Detection of pericardial fluid
Describe what a stress echo looks for, what an abnormal result consists of and what it predicts.
- Looks for regional wall motion abnormalities under stress
- An abnormal result consists of new regional wall motion abnormalities or worsening of existing regional wall motion abnormalities during on infusion of dobutamine
- Highly predictive of adverse cardiac events
When do you order a pre-op Echo?
- Current or prior HF with worsening dyspnea or other change in clinical status
- Dyspnea of unknown origin
- Maybe for aortic stenosis
What is the best method for defining coronary anatomy?
Coronary angiography
What information is obtained from coronary angiography?
- Diffuseness of obstructive disease
- Adequacy of any previous angioplasties or bypass grafts
- CA spasms
- LV pressures, volumes, and EF
- Valvular lumen area and valve gradients: pressure gradients across valves and shunts as well as degree of regurgitation, PA pressures, CO and SVR
What is the gold standard test for undergoing cardiac surgery?
Coronary angiography
When should a patient have a pre-op cath?
- Stable angina with left main CAD
- Stable angina with 3 vessel disease
- Stable angina with 2 vessel disease with significant proximal LAD lesion and EF <50% or demonstrable ischemia on noninvasive stress testing
- High-risk unstable angina or non-ST elevation MI
- Acute ST-elevation MI
How long after a balloon angioplasty should a pt wait before surgery?
At least 14 days
How long after a Bare-metal stent should a pt wait before surgery?
At least 30-45 days
How long after a drug-eluting stent should a patient wait before surgery?
At least 365 days
What are MRIs used to assess and what can they detect/determine in cardiac patients?
- Used to assess function and viability of myocardium
- Sensitive in detecting infarctions using gadolinium
- Good at determining intracardiac tissue characterization
What conditions are considered high risk for development of subacute bacterial endocarditis?
- Prosthetic heart valves
- History of infective endocarditis
- Unrepaired cyanotic congenital heart disease
- Repaired congenital heart defect with prosthetic material or device, during the 1st 6 months after the procedure
- Repaired congenital heart disease with residual defects
- Cardiac transplant recipients with cardiac valvular disease
For patients with high risk of subacute bacterial endocarditis when is antibiotic prophylaxis recommended?
- All dental procedures that involve manipulation for gingival tissue, perforation or oral mucosa, or the periapical region of teeth
- Invasive respiratory tract procedures with incision or biopsy or respiratory mucosa
- NOT recommended in genitourinary or gastrointestinal tract surgery unless there is a current UTI
Describe the dosing of antibiotics for subacute bacterial endocarditis.
- All administered as a single dose given 30-60 min before surgery
- Ampicillin 2 gmIV or Cefazolin 1 gm IV of Ceftriaxone 1 gm IV
- If PCN allergy use clindamycin 600mg IV
