CV Assessment Flashcards
What is the goal of prep assessment?
The goal of preop cardiac assessment is to identify patients with heart disease who are at high risk for perioperative cardiac morbidity or mortality or those with modifiable conditions or risk.
Step 1: urgency of surgery
Step 2: determine if active cardiac condition
Step 3: determine surgical risk
Step 4: assess functional capacity
Step 5: assess clinical predictors/ markers
Minor Clinical Predictors of Increased Cardiovascular Risk
Uncontrolled HTN
Abnormal ECG
Low functional capacity
Rhythm other than sinus rhythm
Intermediate Clinical Predictors of Increased Cardiovascular Risk
Intermediate 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)
Major Clinical Predictors of Increased Cardiovascular Risk
Major (Active Cardiac Conditions) Unstable coronary syndromes Acute or recent MI < 1 month Unstable or severe angina Decompensated CHF Significant arrhythmias Severe valvular disease
Risk for Acute Perioperative Infarction
The overall mortality risk of acute MI after GA is about 0.3%
incidence is increased in the patient undergoing intra-thoracic or intra-abdominal surgery or surgery lasting longer than 3 hours
If history of prior MI
greater than 6 months ago, the incidence of perioperative myocardial reinfarction is about 6%
3-6 months ago, the incidence is 10%
within 3 months, 30%
If reinfarction occurs, the mortality rate is @ 50%
Highest risk period within 30 days after acute MI
ACC/AHA guidelines recommend waiting atleast 4-6 weeks post MI before elective surgery
Surgery-specific Risk
High risk:
Intraperitoneal, intrathoracic, aortic surgery and other major vascular surgery, emergent major operations (esp. elderly), prolonged procedures with large fluid shifts/blood loss.
Intermediate risk:
Carotid endarterectomy, peripheral vascular surgery, head and neck, neurologic/orthopedic, and endovascular aneurysm repair.
Low risk:
Endoscopic procedures, superficial, biopsies, cataract, breast surgery, GYN.
What are the basic components of a cardiac assessment overview?
History taking including medications Physical exam Resting 12-Lead ECG, if indicated within 30 days of surgery
What is the goal of obtaining a history?
Goal of history is to elicit
- severity - progression - functional limitations
What are some questions to ask?
Short of breath lying flat (orthopnea)? With exertion?
Congestive heart failure?
Heart attack? Angina (with activity/ @ rest), or chest pain/ pressure/ tightness related to your heart? What are precipitating factors?Associated symptoms
What is frequency? Duration of pain? Methods of relief
Irregular heartbeat or palpitations? Pacemaker? ICD? Heart murmur? Diagnostic tests, therapies, names of treating physician? Problems with blood pressure or HTN? PVD? TIA/CVA?
Diabetes? Renal insufficiency?
High cholesterol?Estrogen status?
Age and weight? Fatigued?
Syncope? Anemia?Smoke or drink alcohol? Illicit drug use?
Patient’s Functional Capacity
Exercise tolerance - in the absence of significant lung disease, is the most “striking” evidence of decreased cardiac reserve.
Duke Activity Status Index
1-4 METS (eating, dressing, walking around house, dishwashing)
4-10 METS (climbing stairs, walk in neighborhood, heavy housework, golf, bowl, dance)
> 10 METS (strenuous sports ie:swimming, tennis, running, football, basketball)
Those patients unable to meet a 4-MET demand are considered to be at higher risk.
Angina
Angina – sign of imbalance between myocardial oxygen supply vs. demand.
Be aware that patients with Aortic Stenosis may experience angina despite normal coronaries.
Esophageal spasm caused by heartburn can result in angina-like pain and can be relieved by NTG.
Approximately 80% of ischemic episodes in CAD patients occurs without angina. (silent)
10-15% of acute MIs are silent.
Prinzmental’s Angina
Vasospastic angina that occurs at rest.
In 85%, there is a fixed proximal lesion in a major artery. 15% have just spasm.
Patients have a higher incidence of migraine HA and Raynaud’s perhaps due to a basic vaso-spastic disease.
Pacemakers and ICD
Things to know:
The indication for insertion of the pacemaker or ICD
The underlying rhythm and rate
The type of pacemaker ( demand, fixed, or radiofrequency), the chamber paced, and the chamber sensed Have the pacemaker or defibrillator interrogated by a qualified member of CIED
Note current settings and battery life Evaluate effect of magnet
Inactivate ICD tachyarrhythmia detection and put defibrillator pads on Device should be evaluated within 3-6 months before surgery
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 (asynchronous mode) 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 oximetry, intra-arterial BP measurement)
Have external pacing available
Physical Exam
Overall appearance Obesity SOB Sternal incision, pacemaker box Heart Heart sounds Murmurs Neck JVD Carotid Bruit Lungs Lung sounds (rales) SOB, effort Vital signs (BP in both arms) Extremities Peripheral edema Pulses Clubbing Skin color
Hypertension
BP readings greater 140/90 mmHg
Major risk factor for cardiovascular mortality.
HTN increases the incidence of stroke, CHF, MI and progression to renal insufficiency and malignant hypertension
Treat HTN if SBP > 160 mmHg and diastolic BP >90 mmHg
Beta-blockers may have a protective benefit
When a patient has hypertension
If patient has long-standing severe HTN or uncontrolled HTN may need to delay surgery to control BP need ECG and serum CR/BUN If on diuretics, CHEM 7 Continue meds Antianxiolytics
Beta Blocker Therapy
ACC/AHA recommendations:
Continue beta blocker therapy
Discontinuation may increase perioperative CV morbidity
Give beta blockers to high risk patients having vascular surgery
Heart Failure
Abnormal contractility or abnormal relaxation of the heart muscle
Can be caused by HTN, IHD
Suspected in the presence of orthopnea, docturnal coughing, fatigue, peripheral edema, 3rd/4th heart sound, resting tachycardia, rales, JVD, ascites
LVH on ECG should raise suspicion
Decompensated HF/ LV function is high-risk and elective surgery should be postponed.
When a Patient has Heart Failure
ECG Chem 7, BUN/ CR BNP (Brain naturetic peptide) < 100pg/mL CXR, if suspected pulmonary edema Echo, as objective measure of LVEF Continue all medications, including beta blockers, hydralazine, nitrates, digoxin, ACEIs (?), ARBs (?), diuretics, anticoagulants (if possible)
Valvular Abnormalities
Identify type of valvular lesion
Evaluate clinical symptoms and testing data
Severe aortic stenosis poses the greatest risk, if valve area is < 1cm2
If symptoms, postpone surgery
Diastolic murmurs always pathologic and require further evaluation
If prosthetic heart valve in place:
May need to bridge anticoagulant therapy
May need SBE (subacute bacterial endocarditis) prophylaxis
Arrhythmias
SVT and ventricular arrhythmias associated with perioperative risk LBBB is strongly associated w/ CAD If new, stress testing or consultation needed Postpone surgery if, Uncontrolled atrial fibrillation Ventricular tachycardia New-onset atrial fibrillation Symptomatic bradycardia High-grade or third degree HB
What medications are cardiac patients on?
Typically on: Beta blockers Statins Aspirin ACE inhibitors/ ARBs Calcium channel blockers Nitro for angina Diuretics Antiarrhythmics Please see Miller 8th ed p 1098 Preoperative Management of Medications
What do you ask/tell the patient about anticoagulants and anti platelet medications?
Need to ask about anticoagulants and antiplatelet medications Antiplatelet (ASA, Plavix) Discontinue 7-10 days prior surgery Anticoagulants (Coumadin, LMWH) Discontinue 3-5 days (Coumadin) INR <1.5 Discontinue 12 hours prior (LMWH) Fibrinolytic drugs (TPA,Streptokinase, Urokinase) Usually cannot discontinue
Chest X ray
Not specific for Ischemic Heart Disease Cardiomegaly Pulmonary vascular congestion/ pulmonary edema (CHF) Pleural effusions Order CXR preop if: Over 75 years old History of CHF Symptomatic cardiovascular disease
12-Lead
Recommendations for Preoperative Resting 12-Lead ECG
All vascular surgery patients
CAD, PAD, CVD AND intermed. risk surgery
Maybe 1 or more clinical risk factor plus intermed. risk surgery
No- asymptomatic patients plus low risk surgery
Reviewed For:
1) Acute Myocardial ischemia
2) Prior myocardial infarction
3) Rhythm or conduction disturbances
4) Cardiomegaly or ventricular hypertrophy
5) Other ECG abnormalities, Electrolyte imbalances
ECG Indicators of Acute Ischemia
5 Principle Indicators:
ST segment elevation , ≥1mm
T wave inversion
Development of Q waves
ST segment depression, flat or downslope of ≥1mm
Peaked T waves
When to do a 12-Lead
Atleast 1 clinical risk factor having vascular surgery
Known CAD, PVD, CVD having intermediate or high risk surgery
Maybe, if—
No clinical risk but vascular surgery
Atleast 1 clinical risk factor having intermediate or high risk surgery
Not needed in asymptomatic patients having low risk surgery
ACC/AHA recommends ECG within 30 days of surgery
What lab data to you look at?
To ascertain general medical condition related to comorbidities K+ BUN/ Cr ABG’s Hbg/ Hct INR/ PT
Treadmill exercise stress testing
Simulates sympathetic nervous system stimulation by increasing BP and HR and therefore increasing myocardial O2 demand and consumption w/ exercise
Look for ischemia by ECG changes
Interpreted based on:
a) Duration of exercise the patient can perform
b) Max. HR achieved
c) Time of onset of ST depression
d) Degree of ST depression
e) Time until resolution of the ST segment
What is a positive test/predictive of CAD?
ST-segment depression > 2.5mm
ST-depression occurs early in test (first 3 minutes)
Serious ventricular arrhythmias
Prolonged duration of ST depression in post recovery period
Non-ECG responses
If increase in BP or HR occurs at time of ST-depression
If hypotension occurs
Hypotension an ominous sign
Pharmacologic Stress testing
Useful in patients unable to exercise
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
The area of decreased perfusion (cold spot) only during stress shows ischemia, whereas a constant perfusion defect suggests old MI.
Areas of redistribution defects are at higher risk of ischemia and infarction
Look for ischemia by perfusion imaging, not ECG changes
When to Request Stress Testing
Active cardiac condition
Unstable coronary syndromes
Unstable 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:
Atleast 1-2 clinical risk factors and poor functional capacity having intermediate risk surgery if it will change management
Atleast 1-2 clinical risk factors and good functional capacity having vascular surgery
Echocardiography
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
Stress Echocardiography
Look 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 an infusion of dobutamine (exercise/stress)
Highly predictive of adverse cardiac events
When to order a prepop echo
Current or prior heart failure
with worsening dyspnea or other change in clinical status
Dyspnea of unknown origin
?Aortic stenosis
Coronary Angiography
Provides best method defining coronary anatomy
Information obtained
Diffuseness of obstructive disease
Adequacy of any previous angioplasties or bypass grafts
CA spasms
LV pressures, volumes, and EF
LV dysfunction: akinesis, dyskinesis, low EF, high LVEDP
Valvular lumen area and valve gradients
Pressure gradients across valves and shunts, as well as degree of regurgitation
PA pressures
CO and SVR
Gold standard test for undergoing cardiac surgery
When to have a prep catheterization
Stable angina with Left main CAD
Stable angina with 3-vessel disease
Stable angina 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
Previous Percutaneous Coronary Interventions and Surgery
BALLOON ANGIOPLASTY – wait >14 days
BARE-METAL STENT – wait > 30-45 days
DRUG-ELUTING STENT – wait > 365 days
MRI
Magnetic resonance imaging
Used to assess function and viability of myocardium
Highly sensitive in detecting infarctions using gadolinium
Also good at determining intracardiac tissue characterization
Subacute Bacterial Endocarditis (SBE) Prophylaxis
Guidelines updated in 2006
High-Risk Cardiac Conditions
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 transplantation recipients with cardiac valvular disease
For patients with high cardiac risk, antibiotic prophylaxis is recommended for:
All dental procedures that involve manipulation for gingival tissue, perforation of oral mucosa, or the periapical region of teeth
Invasive respiratory tract procedures with incision or biopsy of respiratory mucosa
NOT recommended in genitourinary or gastrointestinal tract surgery*
Only if current UTI
Subacute Bacterial Endocarditis (SBE) Prophylaxis Antimicrobials
All antimicrobial prophylaxis are administered as a single dose, given 30-60 min. before procedure Standard prophylaxis Ampicillin 2 gm IV Or Cefazolin 1 gm IV Or Ceftriaxone 1 gm IV If PCN allergic, Clindamycin 600 mg IV
