Download Strategies to Reduce Cardiac Risk in a Non_Cardiac surgery

Strategies to Reduce Cardiac Risk in a Non_Cardiac surgery
Professor Anil Ohri
MD,DA. Pain Management &Critical care, Disaster Management
Department of Anaesthesia, Indira Gandhi Medical College, Shimla-1
Summary: Reduction of risk in noncardiac surgery requires good anaestheia technique which
provide complete pain relief and reduce myocardial oxygen demand,good perioperative
monitoring(use of 12 lead ECG and in selected cases TEE my help in detecting mild ischemia or
arrhythmias),selection of patients,good history and provide cardiac evaluation if needed can
reduce the risk in noncardiac sugery. Not only this use of drugs like biosoprolol (in intermediate
risk patients)or as a matter of fact any b-blocker like metoprolol and statins like flavistatin (in
high risk patients)can help reducing risk in non-cardiac surgery. Invasive investigations/or
myocardial revascularization in extreme cases rarely required. Rare use of circulatory assist
devices in cases marked reduction of left ventricular ejection fraction. Preoperative
revascularization rarely required in non-cardiac surgery.
Preoperative Issues Requiring Consideration:
1) How healthy is the patient? 2) How active is the patient? 3) How risky in the planned
surgery? 4) Is preoperative cardiac testing necessary? 5) What preventive measures can be
taken to reduce cardiac?
Risk involved and Magnitude of Problem:
Patients can be divided in to low risk: Patients without clinical evidence of heart disease have a
low risk of MI (0.15%) and High risk: Perioperative MI is associated with a 40-70% mortality
rate or any History Of MI in the past.Data available shows 25 million patients undergo
noncardiac surgery each year in the United States & 3 million patients have clinical evidence or
multiple risk factors for CAD. Not only this, 4 million patients are > 65 years old & Nearly 1/3
of surgical patients are at risk for cardiovascular complications.Coronary heart disease is the
most frequent cause of perioperative cardiac mortality and morbidity after noncardiac surgery.
Goals of Reducing Risk
1) To identify patients at risk through history, physical examination & ECG. 2) To evaluate the
severity of underlying cardiac disease through cardiac tests. 3) Stratify the extent of risk 4)
Determine the need for preoperative interventions to minimize risk of peri-operative
complications
Causes of Increased Cardiac Risk & Purpose of Evaluation:
Causes of increase cardiac risk are disease conditionCAD (severity and stability, CHF,
Arrhythmias, Valvular diseases, Pulmnary vascular disease, Age, Type of Surgery, Functional
capacity and Comorbid conditions: DM, Renal dysfunction, CVA. Evaluate patient’s current
medical status,provide clinical risk profile,decision on further testing,recommended management
of cardiac risk over entire perioperative period,treatment of modifiable risk factors and NOT
SIMPLY TO GIVE MEDICAL CLEARANCE. Preoperative cardiac evaluation involvesReview of history, Physical examination, Diagnostic tests. Initial evaluation focuses on: 1.
Knowledge of the planned surgical procedure. Preoperative risk assessment (The initial history,
physical examination, and electrocardiogram assessment should focus on identification of
potentially serious cardiac disorders.) 2. In addition to identifying the presence of pre-existing
manifested heart disease, it is essential to define disease severity, stability, and prior treatment
(Anticoagulation and antithrombotic issues) 3. Postoperative Management & Endocarditis
prophylaxis
Problems to be Sorted Out:
Can these patients reasonably have non-cardiac surgery? Is there a need for further testing?Any
drugs to be started. Keep him in ICU before surgery..How many ECGs in post op….Role of
intra-op NTG? Would coronary revascularization improve the long-term prognosis from a
cardiac standpoint and protect the patient from adverse events during the necessary non-cardiac
surgery?
General Approach to Patients:
History of the patient like angina, recent or past MI, CHF, symptomatic arrhythmias & presence
of pacemaker or ICD, physical examination of the patient i.e. general appearance, rales, elevated
JVP, carotid and other arterial pulses, S3 gallop, murmurs. Comorbid Diseases like
pulmonary,diabetes Mellitus,renal Impairment & hematologic Disorders. . Ancillary studies
shows that - ECG, blood chemistries, chest X-ray give good picture of the patients cardiac
status. Value of ECG can not be under estimated. ECG is frequently obtained as part of
preoperative evaluation in all patients over a specific age or undergoing a specific set of
procedures.Metabolic , electrolyte disturbances, medications, intracranial disease, pulmonary
disease can alter ECG. Not only this conduction disturbances (RBBB) or first-degree AV block,
may lead to concern but usually do not justify further workup.Importance of ECG: Preoperative
resting electrocardiogram is readily available, inexpensive, easy to perform and able to interpret
and detect previous myocardial infarction, acute ischemia, or arrhythmias. The presence of
abnormalities such as Q waves and non sinus rhythms has been shown to correlate with adverse
postoperative cardiac events. Indicators of Pre-operative Testing: 1.Patients with intermediate
clinical predictors. 2. Prognostic assessment of patients undergoing initial evaluation for
suspected or proven CAD. 3. Evaluation of patients with change in clinical status. 4. Evaluation
of adequacy of medical treatment. 5. Prognostic assessment after an acute coronary syndrome.
Indications of Preoperative Cardiac Testing:
1. Patients with intermediate clinical predictors. 2. Prognostic assessment of patients undergoing
initial evaluation for suspected or proven CAD. 3. Evaluation of patients with change in clinical
status. 4. Evaluation of adequacy of medical treatment. 5. Prognostic assessment after an acute
coronary syndrome. NONINVASIVE TESTS Resting tests – Resting ECHO & Exercise tests
and pharmacologic tests: a) .Exercise stress test. b) .DSE. c) DTS. d) Adenosine stress test. e)
Ambulatory ECG monitoring (FIG-1)
Preoperative Coronary Angiogram/Coronary intervention:
CLASS I: - 1. Patients with stable angina who have significant LMCA stenosis and patients
with stable angina who have 3-vessel disease. 2. (Survival benefit is greater when LVEF is less
than 0.50.) 3. Patients with stable angina who have 2-vessel disease with significant proximal
LAD stenosis and either EF less than 0.50 or demonstrable ischemia on noninvasive testing. 4.
For patients with high-risk unstable angina or non– ST segment elevation MI. 5. Coronary
revascularization before noncardiac surgery is recommended in patients with acute ST-elevation
MI. (All have level of evidence A).
Suggested initial clinical assessment of patients undergoing non-cardiac surgery
Figure 1: Auerbach A, and Goldman L Circulation. 2006;113:1361-1376
Pre-Operative Clinical Index
Functional capacity expressed in metabolic equivalent (MET) levels
Oxygen consumption (VO2) of 70Kg, 40-yr-old man in resting state is
3.5 ml/kg/mt or 1 MET
>10 METS - Excellent
4-7
- Moderate
7-10 METS - Good
<4
- Poor
Patients with a low functional capacity (less than 4 Mets) have a worse prognosis than patients
with a good functional capacity
Functional Capacity (Assessment)
Expressed in metabolic equivalent (MET) levels






Can you take care
1 MET
Of yourself?
Eat, dress, or use the toilet?
Walk indoors around the house?
Walk a block or two on level ground at
2-3 mph or 3.2 -4.8 km/h?.
Do light work around the house like
dusting or washing dishes?
4 MET
Climb a flight of stairs or walk up a hill? 4
MET
 Walk on level ground at 4 mph or 6.4
km/h?
 Run a short distance?
 Do heavy work around the house like
scrubbing floors or lifting or moving
heavy furniture?
 Participate in moderate recreational
activities like Golf, bowling, dancing,
doubles Tennis, or throwing a baseball
or football?
 Participate in strenuous sports like
swimming, singles tennis, football,
basketball, or skiing?
10 MET
Clinical Predictors for Increased Perioperative Cardiovascular Risk
Major (cardiac risk > 5%)
 Unstable coronary
syndromes
 Decompensated CHF
Significant Arrhythmias
Minor
(cardiac risk < 1%)
 Advanced Age.
 Abnormal ECG.
 Rhythm other than
sinus.
 Low
functional
capacity.
 History of stroke.
 Uncontrolled systemic
 hypertension
 Severe valvular disease
Intermediate (cardiac risk<
5%)
 Mild angina pectoris
 Prior MI
 Compensated or prior
HF
 Diabetes Mellitus
(particularly taking
insulin)
 Renal insufficiency
Surgical Risk
High Urgency
 Urgency
(cardiac
complcations 2
to 5 times
more)
 Emergent
major
operations,
particularly in
the elderly
 Aortic and
other major
vascular
surgery
 Peripheral
vascular
surgery
 Anticipated
prolonged
surgical
procedures
 associated with
large fluid
shifts and/or
blood loss
Surgical Risk
(Intermediate)
 Carotid
endarterectomy
 Head and neck
surgery
 Intraperitoneal
and intrathoracic
 Orthopedic
surgery
 Prostate surgery
Low
Surgical
Risk
Major Clinical Predictors
 Acute (<7 days) or
Recent MI (7 days1 month)
 Unstable or severe
angina
 (Canadian class III
or IV)
 Significant
Arrythmias
 High grade
atrioventricular
block
 Symptomatic
ventricular
arrhythmias in the
presence of
underlying heart
disease
 Supraventricular
arrhythmias with
uncontrolled
ventricular rate
Table 3: Laboratory Tests to Risk-Stratify
(BNP-b-type Natriuretic Peptide,N-Terminal,Hb A1c,IGT(Glucose Intolerance) Patients
UndergoingNon Cardiac SurgeryNoncardiac Surgery(BNP-b-type Natriuretic Peptide,NTerminal,Hb A1c,IGT(Glucose Intolerance)
. Dernellis et al BNP≥189 pg/mL
. Feringa et al
NT proBNP≥270 ng/L
. Feringa et al
HbA1c≥7%
. Feringa et al
GT5.6-7.0 mmol/L . (Feringa et al
DM≥7 mmol/L HR Odds ratio for each
1 ng/L rise in the natural logarithm of baseline NT proBNP. †Hazard ratio for all-cause
mortality ‡Hazard ratio for major adverse cardiac events. §Fasting glucose values.Odds ratio
for each 1 ng/L rise in the natural logarithm of baseline NT proBNP.)
Additional Risk Stratification and Treatment before Non-Cardiac Surgery
Figure 2: Aurbach A, and Goldman L Circulation 2006;113:1361-1376
Various Cardiac Risk Index and Their Value:
1. ASA. 2. NYHA/CCS. 3 Goldman ( 1977). 4. Detsky (1997 ). 5.ACC/AHA(updated in 2007)
6.ACP. 7. Lee ( 1999 ). 8. Cooperman ( 1978 ). 9.Larsen( 1987 ). 10. Pedersen ( 1990 ). 11.
Vanzetto ( 1996 ). ASA – used for assessment of the patient’s overall physical status and to
predict morbidity & mortality. Value- NYHA/CCS - used for risk stratification of medical
patients with angina, but they have been adapted for use in surgical patients. Cardiac Risk Index
(CRI) by Goldman et al identified 9 independent variables that correlated with adverse
perioperative events. Modified Cardiac Risk Index ,is modified by Detsky et al identified risk
factors for cardiac morbidity but were very cumbersome to apply.Revised Cardiac Risk Index
(RCRI) by Lee identified 6 independent predictors of adverse cardiac outcome in patients
undergoing noncardiac surgery.Eagle’s Risk Indices: Thallium Scan,Q-wave,Age>70 years
etc.ACC/AHA guidelines : The ACC/AHA guidelines provide a framework for screening and
identifying patients who are at high risk for perioperative cardiac
The Accuracy of any of the above risk indices is controversial: 1. cardiac risk index to be useful,
has to be applicable to all and be consistently accurate. 2.They couldn’t be applied to all
surgeries. 3.They were at times cumbersome to apply. 4.Non prospective.
Preoperative Care in Some High Risk Patients:
Recommendation: Based on scanty evidence, preoperative preparation in intensive care unit
may benefit certain high risk patients, particularly those with decompensated Heart Failure.
Goal: Optimize and augment oxygen delivery in patients at high risk
Hypothesis: Indices derived from pulmonary artery catheter and invasive blood pressure
monitoring can be used to maximize oxygen delivery, which leads to reduction in organ
dysfunction
Reasons of Risks in These Patients: Reasons for risk in these patients are:- Major
hemodynamic stress, Changes in cholinergic activity,Changes in catecholamine activity,Body
temperature fluctuations,Pulmonary function is altered,Fluid shifts > 1500 ml and Pain.
Anaesthesia (RISK):
•
Decreased systemic vascular resistance, Decreased stroke volume,
•
Induction of general anesthesia lowers systemic arterial pressures by 20-30%, tracheal
intubation increases the blood pressure by 20-30 mm Hg, and many anesthetic agents
lower cardiac output by 15%.
Anaesthesia Technique:
1.Decreased stroke volume, Any anesthetic technique that does not effectively eliminate pain
will be associated with markedly increased cardiac demands
2.Choice should be left to the discretion of the anesthesia care team.
3.Opiod-based anesthetics popular because of cardiovascular stability, but high dosages result in
postoperative ventilation
Role of Intraoperative Nitroglycerine: High-risk patients previously taking nitroglycerin who
have active signs of myocardial ischemia without hypotension.
Monitoring in Peri-Operative Period:
1. Patients without evidence of CAD-Monitoring restricted to those who develop preoperative
signs of cardiovascular dysfunction.
2. Patients with known or suspected CAD, and undergoing high or intermediate risk procedure:.
ECGs at baseline, immediately after procedure, and daily x 2 days.Cardiac troponin (<1.5ng/ml)
measurements 24 hours postoperatively and on day 4 or hospital discharge (which ever comes
first)
Risk Reduction strategies:
1.Perioperative management :- a. Anesthetic techniques.i)General versus regional anesthesia , ii).
Temperature regulation ,iii) Invasive monitoring – PAC, TEE. b. Surgical approach: i.
Laparoscopic, endovascular procedures. 2.Management : a. Beta blockers.b).A2Agonists(Vascular surgery Only)c. Other anti-ischemic medications. d. Statins. 3. Preoperative
coronary revascularization / Valvuloplasty(In Extreme Cases only and Rarely requiered)
Conclusion: Thorough history,Detailed physical examination,Judicious use of tests. Categorize
patients into low, intermediate & high risk category .Combine preop assessment with periop risk
reduction strategies & optimize medical treatment to improve outcome. Investigations should be
done if they are going to change the management.
References:
1.Olaf Schouten, Jeroen J Bax, and Don Poldermans Assessment of cardiac risk before
non‐cardiac general surgery. Heart. Dec 2006; 92(12): 1866–1872.
2. Fleisher LA, Eagle KA: Clinical practice: Lowering cardiac risk in noncardiac surgery. N Engl
J Med 2001; 345:1677–82
3. Wenger NK: A 50-year-old useful report on coronary risk for noncardiac surgery. Am J
Cardiol 1990; 66:1375–6
4. Mangano DT, Layug EL, Wallace A, Tateo I: Effect of atenolol on mortality and
cardiovascular morbidity after noncardiac surgery. Multicenter Study of Perioperative Ischemia
Research Group. N Engl J Med 1996; 335:1713–20
5. Mercado, DL; Ling, DY; Smetana, GW Southern Medical Journal, 100(5): 486-492.
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6. Adam W. GrassoWael A. Jaber Reducing cardiac risk in non-cardiac surgery: evidence from
the DECREASE studiesDon Poldermans1,*, Olaf Schouten1, Jeroen Bax2 and Tamara A.
Winkel1,2014