PREOPERATIVE EVALUATIONOF CARDIAC PATIENT (For Non-Cardiac Surgery)

Dr Thomas KoshyAdditional Professor

Sree Chitra Tirunal Institute forMedical Sciences and Technology

Trivandrum

The risk

Low risk: Patients without clinical evidence of heart disease have a low risk of MI (0.15%)

High risk: Perioperative MI is associated with a 40-70% mortality rate

Magnitude of the problem

25 million patients undergo noncardiac surgery each year in the United States

3 million patients have clinical evidence or multiple risk factors for CAD

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

THE CASE

Adult with DM – elective non-cardiac surgery

Adult with systemic HT– elective non-cardiac surgery

52 year old school teacher from Kottayam

large frontal meningioma

inf wall MI 2 years back

On atenelol and sorbitrate

The questions Can these patient reasonably have noncardiac

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 intraop NTG Would coronary revascularization improve the long-

term prognosis from a cardiac standpoint and protect the patient from adverse events during the necessary noncardiac surgery?

Factors increasing cardiac risk

Disease condition(severity and stability)-CAD, CHF, Arrhythmias, Valvular diseases, Pulm vascular disease

Age Type of Surgery Functional capacity Comorbid conditions: DM, Renal dysfn, CVA

Purpose of Preoperative Evaluation

Evaluate patient’s current medical status

Provide clinical risk profile

Decision on further testing

Recommend management of cardiac risk over entire

perioperative period

Treatment of modifiable risk factors

NOT SIMPLY TO GIVE MEDICAL CLEARANCE

Roles of Clinicians

Cardiologist

Anaesthesiologist

Surgeon

Role of the Cardiologist

Review available patient data, history and physical examination

Determine if further testing is needed to define cardiovascular status

Recommend treatment to improve medical condition

Participate in postoperative medical management

General Approach to the Patient History – angina, recent or past MI, CHF,

symptomatic arrhythmias, presence of pacemaker or ICD

Physical Examination – general appearance, rales, elevated JVP, carotid and other arterial pulses, S3 gallop, murmurs

Comorbid Diseases Pulmonary Diabetes Mellitus Renal Impairment Hematologic Disorders

Ancillary Studies - ECG, blood chemistries, chest X-ray

Clinical Predictors of Increased Perioperative Cardiovascular Risk

Major (cardiac risk > 5%) Unstable coronary syndromes Decompensated CHF Significant Arrhythmias Severe valvular disease

Intermediate (cardiac risk< 5%) Mild angina pectoris Prior MI Compensated or prior HF Diabetes Mellitus (particularly taking

insulin) Renal insufficiency

Minor (cardiac risk < 1%)

Advanced Age. Abnormal ECG. Rhythm other than sinus. Low functional capacity. History of stroke. Uncontrolled systemic hypertension

Unstable coronary syndromes(major clinical predictor)

Acute (<7 days) or Recent MI (7 days-1 month)

Unstable or severe angina

(Canadian class III or IV)

Significant Arrhythmias (major clinical predictor)

High grade atrioventricular block

Symptomatic ventricular arrhythmias in the

presence of underlying heart disease

Supraventricular arrhythmias with

uncontrolled ventricular rate

Type of Surgery Urgency (cardiac compl 2 to 5 times more) High surgical risk:

Emergent major operations, particularly in the elderly

Aortic and other major vascular surgeryPeripheral vascular surgeryAnticipated prolonged surgical procedures associated with large fluid shifts and/or blood loss.

Type of Surgery Intermediate surgical risk:

Carotid endarterectomy

Head and neck surgery

Intraperitoneal and intrathoracic

Orthopedic surgery

Prostate surgery

Type of Surgery

Low surgical risk: Endoscopic procedures

Superficial procedures

Cataract surgery

Breast surgery

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

Functional capacity

>10 METS - Excellent 7-10 METS - Good

4-7 - Moderate <4 - Poor

Patients with a low functional capacity (less than 4 Mets) have a worse prognosis than

patients with a good functional capacity

Assessment of Functional capacity

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 4 MET the house like dusting or washing dishes?

• Climb a flight of stairs or walk 4 MET up a hill?• 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 10 MET like swimming, singles tennis, football, basketball, or skiing?

Indications for further testing

No further testing required

Coronary revascularization within 5 years and no recurrent symptoms.

Benign Coronary evaluation within 2 years and no change in symptoms.

Stepwise Approach to Preoperative Cardiac Assessment

AMERICAN COLLEGE OF CARDIOLOGYAMERICAN HEART ASSOCIATION

ALGORITHM

FORFURTHER TESTING TO CONFIRMTHE DIAGNOSIS AND EXTENT OF

CORONARY ARTERY DISEASE

Circulation 2002;105:1257-68 and J Am Coll Cardiol 2002;39:542-53

Major clinical predictors

Intermediate predictors

Minor predictors

Further Non-invasive testing

if 2 or more of following present: Intermediate clinical predictors (Canadian Class I or II

angina, prior MI based on history or pathological Q waves, compensated or prior HF, or diabetes)

Poor functional capacity (<4 METs) High surgical risk procedure (emergency major surgery*,

aortic repair or peripheral vascular, prolonged surgical procedures with large fluid shifts or blood loss)

* Emergency major operations may require immediately proceeding to surgery without sufficient time for noninvasive testing or preoperative interventions.

No further preoperative testing recommended

Preoperative angiography

Ex ECG

Exercise echo or perfusion imaging‡**

Pharmacologic stress imaging (nuclear or echo)

Dipyridamole or adenosine perfusion

Dobutamine stress echo or nuclear imaging

Other (eg, Holter monitor, angiography)

Yes

Prior symptomatic arrhythmia(particularly ventricular

tachycardia)?Borderline or low blood pressure?

Marked hypertension?Poor echo window?

No

Yes

Prior symptomatic arrhythmia

(particularly ventricular tachycardia)?

Marked hypertension?

Bronchospasm?II AV Block?

Theophylline dependent?Valvular dysfunction?

No

No

Resting ECG normal?

Patient ambulatory and able to exercise?‡

Yes

No

YesYes

Indications for angiography? (eg, unstable angina?)

Yes

Yes

No

No

Testing is only indicated if the results will impact care.

2 or more of the following?†*1. Intermediate clinical predictors2. Poor functional capacity (less than

4 METS)3. High surgical risk

When and Which Test(For the cardiologist)

Non Invasive tests

Exercise stress testing- Ex ECG

Nonexercise stress testing:o Dobutamine stress echocardiography.o Myocardial perfusion imaging

Ambulatory electrocardiographic monitoring.

Management Options after Noninvasive Testing

Intensified medical therapy

Cardiac catheterization Cancel or delay surgery Proceed with surgery Coronary revascularization prior to surgery

Preop Coronary angiography (Class I indications)

High-risk results during noninvasive testing Angina pectoris unresponsive to adequate

medical therapy Most patients with unstable angina Nondiagnostic or equivocal noninvasive test

in a high-risk patient undergoing a high-risk noncardiac surgical procedure

Preop Coronary angiography(Class II indications)

Multiple markers of intermediate-risk during noninvasive testing

Nondiagnostic or equivocal noninvasive test in a lower-risk patient undergoing a high-risk noncardiac surgical procedure

Urgent noncardiac surgery in a patient convalescing from acute MI

Preoperative CABG

No randomized clinical trials documenting decreased incidence of perioperative cardiac events

Patients with prognostic high risk coronary anatomy in whom long-term outcome would likely be improved

Noncardiac elective surgical procedure of high or intermediate risk.

Preoperative CABG Indications are same as those in the

nonoperative setting

Cardiac risk of CABG often exceeds that of noncardiac surgery

Rarely indicated simply to get a patient through the perioperative period

Preopoperative PTCA

No controlled trials Several small observational studies suggest

that cardiac death is infrequent in patients who have PTCA prior to noncardiac surgery

Indications are similar to those in nonoperative setting

Preoperative Medical therapy

Few randomized trials Studies suggest B-blockers reduce

perioperative ischemia and may reduce risk of MI and death

Alpha-agonists may also reduce cardiac events when administered perioperatively

Poldermans D. NEJM 1999;341:1789-1794

Valvular Heart Disease

Indications for evaluation/treatment identical to those in nonoperative setting

Symptomatic stenotic lesions associated with risk of perioperative CHF/shock

Symptomatic regurgitant lesions usually better tolerated perioperatively

Hypertension

Perioperative swings of pressure often occur in hypertensive patients

Patients who are adequately treated preoperatively have less marked deviations of blood pressure

Surges of BP most common during: Induction Intubation Skin incicision 12 to 24 hours post-op

Preoperative Intensive care

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

Preoperative Intensive care

Recommendation: Based on scant evidence, preoperative

preparation in intensive care unit may benefit certain high risk patients, particularly those with decompensated HF.

Anesthetic Considerations and Intraoperative Management

No study clearly demonstrated improved outcome from use of: Regional versus general anesthesia Pulmonary artery catheter Intraoperative Nitroglycerin ST-Segment Monitoring Transesophageal echocardiography Prophylactic placement of intra-aortic

balloon counterpulsation device

Intraoperative Nitroglycerine

High-risk patients previously taking nitroglycerin who have active signs of myocardial ischemia

without hypotension

Anaesthesia

Any anesthetic technique that does not effectively eliminate pain will be associated with markedly increased cardiac demands

Choice should be left to the discretion of the anesthesia care team

Opiod-based anesthetics popular because of cardiovascular stability, but high doses result in postoperative ventilation

Perioperative Surveillance

Patients without evidence of CAD: Surveillance restricted to those who develop perioperative

signs of cardiovascular dysfunction

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 measurements 24 hours postoperatively and on day 4 or hospital discharge (whichever comes first)

52 year old school teacher from Kottayam

large frontal meningioma

inf wall MI 2 years back on sorbitrate and atenelol

Good functional capacity by history 4-7 METS

positive treadmill test , acheived 7 METS coronary angiogram tripple vessel disease-

LAD - 75% block

OM 1- 90% block

RCA - 75% block LVEDP (post angio)-14

Cardiologist’s opinion – CABG before surgery

Functional limitation correlates with perioperative riskAnatomical severity is important for long term prognosis (Braunwald)

Summary

1. Integration of clinical risk factors, surgery specific risk and functional capacity should be utilised to determine the need for further diagnostic evaluation

2. Use of beta blockers in high risk patients has been shown to reduce perioperative risk

3. Coronary intervention is reserved for patients who warrant intervention independent of non-cardiac surgery