Cardiac Flashcards
1
Q
What is the goal of pre-op cardiac assessment?
What are the 5 steps?
A
- Goal: identify patients with heart disease who are at high risk for perioperative cardiac morbidity or mortality or those with modifiable conditions or risks
- Steps:
- urgency of surgery
- determine if active cardiac condition
- determine surgical risk
- assess functional capacity
- assess clinical predictors/markers
2
Q
What are the clinical predictors of minor increased cardiovascular risk (7)
What is the chance of having an event?
A
- HTN
- abnormal ECG
- smoking
- increased age/male sex
- hypercholesterolemia
- rhythm other than sinus
- family history
- <1% chance of having an event
3
Q
What are the clinical predictors for an intermediate increase in cardiovascular risk?
A
- 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 > 2.0 mg/dL
- Cerebrovascular disease
- stroke, TIA
4
Q
What are the clinical predictors for a major cardiovascular risk?
A
- unstable coronary syndromes
- acute or recent MI <1 month
- unstable or severe angina
- decompensated CHF
- significant arrhythmias
- HB, afib (depending on how controlled the rate is), vtach
- Severe valvular disease
- mitral, aortic stenosis
5
Q
What is the overall mortality risk of an acute MI after GA?
When is this risk increased?
A
0.3%
Incidence is increased in the patient undergoing intrathoracic or intra-abdominal surgery or surgery lasting longer than 3 hours.
6
Q
What is the risk of mortality with history of prior MI?
> 6 months ago?
3-6 months ago?
within three months?
within 7 days?
If reinfarction occurs?
A
- > 6 months ago: risk is 6%
- 3-6 months ago: risk is 10%
- within 3 months: 30%
- within 7 days: postpone surgery
- If reinfarction occurs, the mortality rate is 50%
7
Q
What is the higherst risk period after an MI?
What are the ACC/AHA guidelines?
A
- Highes risk period is within 30 days after an acute MI
- ACC/AHA guidelines recommend waiting at least 4-6 weeks before elective surgery
8
Q
Which surgeries are high risk?
intermediate risk?
low risk?
A
- High:
- intraperitoneal
- intrathoracic
- aortic and other major vascular
- emergent major operations (esp in elderly)
- long procedures with large fluid shifts/loss
- Intermediate
- Carotid endarterectomy
- peripheral vascular surgery
- head and neck
- neurologic/ orthopedic
- endovascular aneurysm repair
- low
- endoscopic procedures
- superficial
- biopsies
- cataract
- breast surgery, GYN
9
Q
What is the “gold standard” test for coronary anatomy?
A
Coronary angiography
10
Q
What do you want to try to figure out from the history, physical, and work up?
A
- severity of cardiac disease
- progression of the disease
- what the patient’s functional limitations are
11
Q
What are some questions you might want to ask a pt you suspect of having cardiac disease?
A
- Do you become short of breath when lying flat (orthopnea) or with exertion?
- Have you ever has a heart attack or CHF?
- Do you have angina or chest pain/tightness?
- what precipitates it?
- what are some associated symptoms?
- how frequent? duration?
- what relieves the pain?
- Do you have irregular heart beats or palpitations?
- pacemaker? ICD?
- heart murmor?
- Problems with BP or on any meds?
- PVD, TIA/CVA?
12
Q
What are some more questions, not directly related to the heart that you would want to ask a cardiac patient?
A
- DM?
- renal insufficiency?
- high cholesterol?
- estrogen status? I.e. menopause- increased risk
- age and weight?
- fatigues?
- syncope?
- anemia?
- smoker? alcohol?
- illicit drug use?
13
Q
How do you assess the pts functional capacity?
A
- Exercise tolerance
- if the pt has no lung disease, this is the most “striking” evidence of decreased cardiac reserve
- Duke activity status Index
- 1-4 METS: eating, dressing, walking around the house, dishwashing
- 4-10 METS: climbing stairs, walk in neighborhood, heavy housework, golf, bowl, dance
- >10: strenuous sports (swimming, tennis, running, football)
- Those unable to meet a 4 MET demad are considered higher risk
14
Q
What is a MET?
A
- Metabolic equivalent of task
- 1 MET = 3.5 mg/kg/min of O2 being consumed
- 70 kg pt = 240 ml O2
- This is the same minimum O2 flow required for a closed circuit
15
Q
What is Angina?
What are some other causes of Angina?
Stats about silent MIs
A
- Angina- sign of imbalance between myocardial oxygen supply vs demand
- Other causes:
- Aortic stenosis- may have angina despite normal coronaries
- Esophageal spasm- caused by heartburn can cause angina that is relieved by NTG
- Silent MIs
- approximately 80% of ischemic episodes in CAD pts occur without angina
- Approximately 10-15% of acute MIs are silent
16
Q
What is prinzmetal’s angina?
A
- Vasospastic angina that occurs at rest
- 85% have a fixed proximal lesion in a major artery, 15% have just spasm
- seen in pts with other vasospastic diseases:
- migrains
- Raynaud’s
17
Q
What do you need to know/do if your patient has a pacemaker and ICD?
A
- Indication for the pacemaker or ICD
- underlying rhythm and rate
- type of pacemaker
- demand- sends electrical pulses if HR is too slow
- fixed- constant frequency
- radiofrequency- can be hacked
- chamber paced vs chamber sensed
-
When was the last time the pacemaker was interrogated by CIED? -prefer within last 3 months
- note settings and battery life
- Evaluate effect of magnet
- Inactivate ICD tachyarrhythmia detection and put defibrillator pads on
- to avoid having the ICD pick up other electricity in OR as a dysrhythmia
18
Q
What can inhibit pacemaker firing in the OR?
What is the magnet for?
What should you monitor?
A
- Electrocautery can have electromagnetic interference that can inhibit pacemaker firing
- Bipolar electrocautery is preferred; avoid monopolar
- Most pacemakers can be converted to a fixed rate (asynchronous mode) by placing a magnet over the pacemaker box
- must have a magnet immediately available
- Have external pacing available
- Monitor some form of blood flow
- pulse ok, A-line
19
Q
Where should the grounding pads be?
A
As far from the pulse generator and leads as possible
20
Q
What are you going to look for upon physical exam of a patient with heart disease?
A
- Overall appearance
- obesity
- SOB
- sternal incision, pacemaker box
- Heart
- sounds
- Murmors
- Neck
- JVD
- Carotid bruit
- Lungs
- sounds
- SOB, effort
- Vital signs- BP in both arms
- Extremeties
- peripheral edema
- pulses
- clubbing
- skin color
21
Q
How do you assess the different heart sounds?
(pic)
What is Erb’s point?
A
Erb’s point is where you can hear S1 and S2 equally
22
Q
What is considered hypertension?
When should it be treated?
A
- HTN is BP > 140/90
- Treat if SBP >160 and DBP >90
- Beta blockers may have protective benefit
23
Q
If pt has long standing severe HTN or uncontrolled HTN, what might you need to do?
A
- May need to delay surgery to control BP
- need ECG and serum BUN/Cr
- if on diuretics, CHEM 7
- continue meds
- Anxiolytic may help
24
Q
What are the 2014 ACC/AHA recommendations regarding Beta blocker therapy?
A
- Continue beta blocker therapy on pts who have been on chronic BB therapy
- discontinuation may increase perioperative CV morbidity
- Start BBs on high risk patients
- >1 day prior to surgery, preferrably 2-7 days
- can be harmful if started day of surgery
25
What is heart failure?
What can cause it?
When is it suspected
* Heart failure- abnormal contractility or abnormal relaxation of the heart muscle
* can be causd by HTN or Ischemic heart disease (IHD)
* Suspected with:
* orthopnea
* nocturnal coughing
* fatigue
* peripheral edema
* 3rd, 4th heart sounds
* resting tachycardia
* rales
* JVD
* ascites
* HF and LV dysfunction is high risk and elective surgery should be postponed
26
What kind of work up do you want to do for a patient with Heart failure?
What meds do you want to continue before surgery?
* ECG
* Chem 7, BUN/Cr
* BNP (normal = \<100 pg/ml
* CXR if you suspect pulmonary edema
* ECHO to objectively measure LVEF
* Continue all medications except ACEs and ARBs
27
Which type of valvular abnormality poses the greatest risk?
What is the deal with diastolic murmors?
What if the pt has a prosthetic heart valve?
* Aortic stenosis- valve area \<1 cm2
* if symptoms, postpone surgery
* Diastolic murmors are always pathologic and require further evaluation
* If pt has prosthetic heart valve
* may need to bridge anticoagulant therapy
* may need bacterial endocarditis prophylaxis
28
Which arrhythmias are associated with perioperative risk?
CAD?
When should you postpone surgery?
* SVT and ventricular arrhythmias are associated with perioperative risk
* LBBB is strongly associated with CAD
* if new, stress testing or consulatation is required
* Postpone surgery if:
* uncontrolled afib
* ventricular tachycardia
* new-onset atrial fibrillation
* symptomatic bradycardia
* high-grade or third degree HB
29
What medications are ppl with cardiac issues typically on?
* beta blockers
* statins
* aspirin
* ACEIs/ARBS
* CCB
* nitro for angina
* diuretics
* antiarrhymics
30
What anticoagulant medications might your patient be on and when should you have them stop taking them?
* Antiplatelet (ASA, Plavix)
* discontinue 7-10 days prior
* Anticoagulants (coumadin, LMWH)
* discontinue Coumadin 3-5 days prior
* discontinue LMWH 12 hours prior
* want INR \<1.5
* may use heparin gtt as bridge therapy, stop 4 hours prior to surgery
* Fibrinolytics (TPA, Streptokinase, Urokinase)
* usually cannot discontinue
31
What can you see regarding the heart on a CXR?
Who should get one?
* NOT specific for IHD, but can see:
* cardiomegaly
* pulmonary vascular congestion/pulmonary edema (CHF)
* pleural effusions
* Order CXR pre-op if:
* pt is over 75 and is high risk
* History of CHF
* symptomatic cardiovascular disease
32
What are the different classes for determining who should get an EKG?
* Class I: Patient **should** get EKG
* if pt has one or more: IHD, hx of heart failure, cerebrovascular disease, DM, renal insufficiency
* And they are getting vascular surgery
* Class IIa: It is reasonable to get EKG if:
* pt has no clinical risk factors (above) but is getting a vascular surgical procedure
* Class IIb: EKG may be considered if:
* they have one or more risk factors (above) and are undergoing and intermediate-risk surgery
* Class III: Should NOT be performed b/c it is not helpful
* in pts who are asymptomatic and undergoing low-risk surgical procedures
33
What do you review a 12-lead EKG to look for?
* acute MI
* prior MI
* rhythm or conduction disturbances
* cardiomegaly or ventricular hypertrophy
* other EKG abnormalities; electrolyte imbalances
34
What are the EKG indicators of acute ischemia?
* ST segment elevation \>/= 1 mm
* T wave inversion
* development of Q waves
* ST segment depression, flat or downslope of \>/= 1 mm
* peaked T waves
35
What leeds do you use to see:
Right side inferior of the heart (RCA)
Right side posterior of the heart (RCA)
* Right inferior (RCA)
* II, III, AVF
* Right posterior (RCA)
* V1, V2, V3
36
What leeds do you use to see:
Left side anterior (LAD)
Left side antero-septal (LAD)
Left side lateral (LCA)
* Left side anterior (LAD)
* I, AVL, V1-V4
* Left Antero-septal (LAD)
* V1, V2, V3, V4
* Left Lateral (LCA)
* I, AVL, V5, V6
37
How does treadmill exercise stress testing work?
What are you looking for?
How is it interpreted?
* Stimulates sympathetic nervous system stimulation by increasing BP and HR and therefore increasing myocardial O2 demand and consumption
* Look for ischemia by ECG changes
* Interpretation based on:
* duration of exercise the patient can perform
* Max HR achieved
* time of onset of ST depression
* degree of ST depression
* time until resolution of ST segment
38
What is considered a positive treadmill stress test?
What is this indicative of?
* Positive stress test: EKG signs
* ST segment depression \>2.5mm
* ST depression occurs early in test (w/in first 3 minutes)
* Serious ventricular arrhythmias
* prolonged duration of ST depression in post recovery period
* Non EKG:
* If increase in BP or HR occurs at the time of ST depression
* if hypotension occurs--this is an ominous sign
* **Indicative of CAD**
39
How is pharmacologic stress testing done?
* IV injection of gamma-emitting radiopharmaceutical (thallium) that permits the imaging of blood within the heart and lungs
* Dipyridamole or adenosine administered as a vasodilator to increase coronary blood flow
* If area of decreased perfusion (cold spot) occurs only during stress, that shows ischemia
* If cold spot is constant, that suggests old MI
* this is a fixed defect, MI is already scarred
* we prefer this because we can't cause the problem?
* Look for ischemia by perfusion imaging, not ECG changes
40
When should you request stress testing?
* Active cardiac condition
* unstable coronary syndromes or severe angina
* recent MI
* decompensated HF
* significant arrhythmias
* Severe valvular disease
* 3 or more clinical risk factors AND poor functional capacity having vascular surgery
* Maybe if:
* 1-2 clinical risk factors and poor functional capacity having intermediate risk surgery, if it will change management
* 1-2 risk factors and good functional capacity having vascular surgery
41
What will and ECHO tell you?
* Measurement of dimensions of cardiac chambers and vessels and the thickness of myocardium
* chamber enlargement
* global ventricular systolic function: EF
* regional wall motion abnormalities
* valve structure and motion
* blood flow and measure gradients
* detect pericardial fluid
42
What do you look for an a stress ECHO and what is that predictive of?
* look for regional wall motion abnormalities under stress
* An abnormal result consists of **new** or worsening of existing regional wall motion abnormalities during an infusion of dobutamine (exercise/stress)
* Highly predictive of adverse cardiac events
43
When should you order a pre-op echo?
* Current or prior heart failure
* w/ worsening dyspnea or other changes
* to reassess LV dysfunction if they have previously documented LVD and it hasnt been reassessed for over a year
* Dyspnea of unknown origin
* clinically suspected valvular disease
* significant change in symptoms
44
What does Coronary angiography tell us?
* diffuseness of obstructive disease
* adequacy of any previous angioplasties or bypass grafts
* CA spasms
* LV pressures, volumes, and EF
* LV dysfunctions- akinesis, dyskinesis, low EF, high LVEDF
* Valve lumen and gradients
* pressure gradients across valves and shunts, as well as degree of regurgitation
* PA pressures
* CO and SVR
* Coronary angiography is the gold standard for cardiac anatomy and ppl undergoing cardiac surgery
45
When should a pt have a pre-op cath?
* Stable angina with left main CAD
* stable angina with 3-vessel disease
* stable angina 2-vessel disease with a significant proximal LAD lesion and EF \<50% or ischemia on non-invasive stress testing
* high risk unstable angina or non-ST elevation MI
* Acute ST elevation MI
46
How long should an elective procedure wait after a previous coronary intervention (revascularization)?
* Balloon angioplast- wait at least two weeks
* Bare-metal stent- wait at least 30-45 days
* Drug-eluting stent- wait 365 days
47
What can an MRI tell us about the heart?
* Assess function and viability of myocardium
* highly sensitive in detecting infarctions using gadolinium (contrast)
* determine intracardiac tissue characterization
* Looking for clots or tumors
48
What are the different toolds used to assess cardiac risk?
* Gupta perioperative cardiac risk tool
* Revised cardiac risk index for pre-op risk (RCRI)
49
Which kind of cardiac conditions should get subacute bacterial endocarditis (SBE) prophylaxis?
* pts with high risk cardiac conditions associated with adverse outcomes from endocarditis
* prosthetic heart valves
* history of infective endocarditis
* congenital heart disease
* unrepaired cyanotic
* if repaired with prosthetic material and within 6 months of repair
* if repaired but still has residual defects
* cardiac transplant
50
If pts are high risk for SBE, which procedures do they need prophylactic antibiotics for?
* all dental procedures that manipulate gingival tissue or perforation of oral mucosa
* invasive respiratory tract procedures
* tonsillectomy, adenoids, abscess drainage, lung biopsy
* procedures involving infection of GI/GU tract, skin/musculoskeletal
* not recommended in routine GI/GU
* hepatobiliary procedures
* cardiac surgery
51
What are the standard SBE prophylaxis antibiotics and when are they administered?
* given within 30-60 minutes before procedure or up to 2 hours after if missed before
* medications:
* ampicillin 2 gm (50 mg/kg peds)
* Cefazolin 1 gm (50 mg/kg peds
* Ceftriaxone 1 gm (50 mg/kg peds)
* If PCN allergic, Clindamycin 600 mg )20 mg/kg peds)
