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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. 10.1097/01,2013 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