Transcript Internal Medicine Lecture Series: Cardaic Cleance.
Internal Medicine Lecture Series: Cardiac Clearance
James Lin, DO July 20, 2005 Millcreek Community Hospital
General Background
Each year 28 million American Adults undergo noncardiac surgery.
1 million have know CAD 2-3 million have cardiac risk factors 4 million are 65 yrs of age or older.
Perioperative Risks:
3 Categories Patient Specific Procedure Specific Anesthesia Specific
Patient Specific:
Many interdependent variables that define the patient and the patient ’ s surgical indications and co morbid diseases. Age Race Gender Nutritional Status Level of fitness Coexisting conditions
ASA
I.
ASA Class No organic or psychiatric disease 0.07% II.
Mild to moderate systemic disturbances 0.20% III.
Severe system disturbance, but not necessarily life threatening 1.15% IV.
Severe systemic disturbance; life threatening 7.66% V.
Moribund with little chance of survival 33.58% In the event of an emergency operation, the number is preceded by “ E ”
Procedure Specific
Risk of a specific surgical procedure is proportional to the physiologic stress associated with the procedure
High Risk Procedures:
Thoracic Surgery Major Joint replacement Craniotomy Cardiac Procedure Large Bowl Surgery Major Head and Neck procedures
Low Level Risk:
Most plastic surgery procedures Tubal Ligation D & C Hysterectomy Eye and Oral surgery Hernia Repairs
Anesthesia Specific
This involves the Direct VS Indirect anesthetic agents and the physiologic responses to: Surgically induced hypotension Blood loss Anemia Post operative pain Most anesthetic deaths are due to failure to ventilate adequately, unsuspected hypoxia, or anesthetic agent overdose.
MANAGING CARDIOVASCULAR RISK
The most common cardiovascular complications are the following: Perioperative acute ischemia and myocardial infarction Congestive hear failure Arrhythmias Hypotension Hypertension
ACC-AHA Preoperative Cardiac Risk Assessment
A.Step 1: Evaluate urgency of noncardiac surgery 1.Emergency requires surgery regardless of risk
A.Step 2: Noninvasive cardiac testing not required 1.Coronary revascularization in past 5 years a.Must be stable and no recurrent symptoms or signs 2.Coronary evaluation in last 2 years a.Evaluation must have been favorable and adequate b.No new symptoms or signs since evaluation
A.Step 3: Indications for noninvasive cardiac testing 1.See Eagle's Cardiac Risk Assessment 2.Major patient risk factors a.Cardiac evaluation needed in all cases 3.Intermediate Risk: Indications for cardiac evaluation a.Decreased functional capacity (<4 METS ) b.Surgery with higher cardiovascular risk See High Risk Surgery 4. Minor risk: Indications for cardiac evaluation a.Evaluate on individual basis b.Consider in decreased functional capacity (<4 METS )
Eagles Cardiac Risk Assessment
A.
B.
C.
D.
E.
Major Cardiovascular Risks: Unstable Coronary Syndromes
Recent MI (within 30 days) Unstable Angina or severe Angina (class 3-4) Decompensated CHF Severe valvular disease Significant arrhythmia A.
B.
C.
High grade AV Block Symptomatic ventricular arrhythmia Uncontrolled rate in supraventricular arrhythmia
Eagle
’
s Cardiac Risk Assessment
A.
B.
Intermediate Cardiovascular Risks
Mild Angina Pectoris (Angina Class 1-2) Prior MI by history or EKG C.
D.
E.
Compensated or prior CHF Renal Insufficiency (serum Creatinine >2 mg/dl) Diabetes Mellitus
Eagle
’
s Cardiac Risk Assessment
A.
Minor Cardiovascular Risks
Advanced age B.
C.
D.
E.
F.
Abnormal EKG (LVH, LBB, ST segment abnormalities, T Wave abnormalities) Hear rhythm other than sinus rhythm (e.g. A-Fib) Low functional Capacity (<4 METS) History of CVA Uncontrolled HTN
NONINVASIVE TESTING
ACC/AHA guidelines, pt with minor clinical predictors do not require noninvasive testing unless they have poor functional capacity and are undergoing a high-risk procedure.
Functional Status Assessment
Excellent >7 METS Moderate 4-7 METS Poor <4 METS Squash Jogging (10 min/ mile) Scrubbing floors Single Tennis Cycling Climbing a flight of stairs Golf without Carts Walking 4 MPH Yard work (e.g, raking leaves, weeding, pushing a power mower) Vacuuming ADL ’ s (eating, dressing, bathing) Walking 2 MPH Writing
ACP Preoperative Cardiac Risk Assessment
A. Indications for surgery without further evaluation.
Young healthy pt undergoing minor surgery Noncardiac emergency surgery
CASE #2:
You are asked to evaluate a 73 y/o male with stable class II angina treated with nitrates and no previous MI or CHF. He has mild hypertension controlled on lisinopril and has no hx of diabetes. He had moderate exercise capacity (5 METS) until he injured his ankle 2 weeks ago. At that time , he was found to have 5.2 cm abdominal, aortic aneurysm. His exam is unremarkable, and his BP is 154/86. His ECG is normal. He is scheduled to undergo AAA repair. You would:
CASE#2: Con
’
t
A) Exercise Stress Test B)DSE Or DTI C) No further cardiac testing and proceed with surgery D) Cardiac Catheterization
CASE #2: Con
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t
B. His history of chronic stable class II angina puts him at intermediate risk before a high risk vascular procedure. Exercise ECG is impractical because of his recent ankle injury. Pharmacological stress testing is the best approach to assess ischemic risk. Even with a negative test result, perioperative atenolol is recommended.
ACP Preoperative Cardiac Risk Assessment
B . Detsky ’ s Modified Cardiac Risk Index Class I Risk Index Eagle and Vanzetto criteria: 0 to 1 Considered low risk of cardiac event 3%. Proceed to surgery without further evaluation Eagle and Vanzetto criteria: 2 or more (see above) Intermediate risk of cardiac event (3-15%) Proceed to surgery without further evaluation. Nonvascular surgery proceeds without evaluation. Vascular surgery evaluation with Stress imaging: Neg. test: Surgery may proceed Pos. Test: Manage as high risk.
ACP Preoperative Cardiac Risk Assessment
Class II or Class III Risk Index: Considered high risk of cardiac event (>15%) Consider revascularization for CAD Manage CHF, arrhythmia, valve disease.
Minimize cardiac risk.
Eagle and vanzetto criteria
Age over 70 yrs Diabetes Mellitus Q waves on ECG Hx of Angina Pectoris Hx of MI Hx of ventricular ectopy Hx of CHF ST segment abnormalities on EKG HTN with LVH
Detsky ’ s Modified Cardiac Risk Assessment
Age older than 70 years 5 MI within 6 months 10 MI after 6 months Canadian Cardiovascular society angina Class III Class IV Unstable Angina within 6Months 5 10 20 10 Pulmonary Edema within 1 week Ever Critical Aortic Stenosis Rhythm other than sinus or sinus plus atrial premature beats More than five premature ventricular beats Emergency operation Poor General medical status 5 5 10 5 10 5 20
Detsky ’ s Modified Cardiac Risk Assessment
I Class II III Points 0 to 15 20 to 30 30 + Cardiac Risk Low High
ACC/AHA VS. ACP
Similarities: Emergent surgery proceeds directly to the operating room without further risk stratification Both algorithms incorporate the Detsky predictors Pts are eventually stratified into low, intermediate, or high risk categories.
ACC/AHA VS. ACP Differences:
ACC/AHA ACP The presence or absence of CAD is the first risk assessment.
Clinical predictors derived from Goldman and Detsky criteria.
Functional status incorporated into the algorithm Pts with poor functional status require stress testing The Detsky criteria are the first determinants of risk stratification.
Minor clinical predictors derived from Eagle and Vanzetto criteria ACP felt functional status not proved to be useful risk predictor Pts undergoing vascular surgery require stress testing.
Case #1:
You are asked to see a 54 year old man with a 15 year history of non insulin-dependent diabetes mellitus and hypertension, currently treated with diet, glyburide, metformin, and lisinopril. He has mild retinopathy and 300 mg/d of proteinuria. His last laboratory studies 2 weeks ago showed a creatinine of 1.4 mg%, total cholesterol of 216 mg%, high density lipoprotein cholesterol 39 mg%, LDL 122 mg%, triglycerides of 210 mg%, and glycosylated hemoglobin of 7.2%. He has no past history of cardiovascular disease and denies current chest pain, palpitations, or dyspnea of exertion. For the past year, he has had limited physical activity due to progressive osteoarthritis of the hip and is scheduled for a total hip replacement in 3 weeks. The surgeon has asked you for advice regarding his perioperative management. On examination, his weight is 220 lb, with a body mass index of 32, his BP is 132/84, and his pulse is 84. His funduscopic examination shows mild background retinopathy. His cardiac and pulmonary examinations are normal, while the remainder of his examination is otherwise unremarkable except for mildly diminished dorsalis pedis pulses, and decreased position sense in his toes. His ECG shows nonspecific ST T changes. As part of your recommendations you would
Case #1 con
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t
A) U/S vascular evaluation of the lower extremities B)Dipyridamole thallium imaging or dobutamine stress echocardiography C) No further cardiac testing and proceed with surgery D)Cardiac catheterization.
Case #1: Con
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t Answer
B. There is room for debate on how to proceed. The patient is clearly at high risk for CAD with longstanding diabetes mellitus, HTN, and a LDL that was high. His planned procedure is of intermediate risk. Given that level of overall risk, many would risk stratify with noninvasive testing.
Case #1: Con
’
t
Your evaluation yields no new findings. As part of his perioperative management, you recommend: A) Holding his oral diabetes medications on the day of surgery B)Maintaining his intraoperative glucose between 150 and 200 mg with regular insulin if necessary C) Atenolol preoperatively and in the immediate postoperative period.
D) All of the above.
Case #1: Con
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t Answer
D. Stopping oral agents on the day of surgery usually is sufficient to protect against hypoglycemia. The anesthesiologist much monitor glucoses intraoperatively and supplement with short-acting subcutaneous insulin to maintain glucoses in the stated therapeutic range. Given the patient ’ s multiple risk factors, atenolol would suppress vascular instability associated with anesthesia induction and withdrawal .