Cardiology: preoperative assessment and investigation

18 March 2011

John Chambers

Risk of myocardial infarction or death at 30 days

• 2.5% in major surgery

• 6.2% vascular surgery

(NB higher if troponin screening)

Mangano Anesthesiology 1998; 88: 561-4; Mangano NEJM 1995; 333: 1750-6

Risk of myocardial infarction or death at 30 days

• 2.5% in major surgery

• 6.2% vascular surgery

(NB higher if troponin screening)

• Mechanism plaque rupture in 50%

• Noninvasive testing limited: medical therapy effective

Mangano Anesthesiology 1998; 88: 561-4; Mangano NEJM 1995; 333: 1750-6

Deaths from aortic stenosis after non-cardiac surgery in the UK

• 10% of postoperative deaths sampled

• Aortic stenosis in 22

• 2 diagnosed at postmortem; in the rest often no echo or invasive monitoring

• Suggests one death from AS p.a. per hospital

National Confidential Enquiry into Perioperative Deaths 2001

1 year mortality with preop stress testing

Revised cardiac risk index score* Hazard ratio

0 1.35

1-2 0.92

3-6 0.80

Wijeysundera. BMJ 2010; 340: 252

Lee. Circulation 1999; 100; 1043-9

Boersma. Am J Med 2005; 118:1134-41

*IHD, CCF, IDD, CRF, CVA, high-risk surgery

Triage of presurgical assessment

• Emergency - Clinical assessment

• Semi-emergency – Cardiac investigation:

– Unstable or severe angina

– Decompensated heart failure

– Significant arrhythmia

– Severe aortic or mitral stenosis

Screening in stable patients with non-emergency surgery

Risk score

Type of surgery Functional capacity

Revised cardiac index risk score

• CAD Distant myocardial infarct; positive exercise test; current angina; use of nitrates; Q waves

• CCF History of CCF or pulmonary oedema;

S3 and rales; chest X-ray evidence

• CVA History of CVA or TIA

• Diabetes On insulin

• CRF Creatinine > 160 micromol/L

• Age > 70

Lee. Circulation 1999; 100: 1043-9; Boersma Am J Med 2005; 118: 1134-41

Estimated energy requirements

• Eat, dress, use lavatory

• Walk inside the house

• Light work like dusting/washing dishes

• Climb 2 flights of stairs/hill

• Walk on level ground at 4.0 mph

• Run for a bus

• Scrub floors/move furniture

• Golf, bowling, doubles tennis

• Swimming, singles tennis

1 MET

4 METs

> 10 METs

Reilly. Arch Intern Med 1999; 159: 2185-92

7 METs

Grades of surgical risk MCI and death

Classification Types of surgery

High Vascular – aortic & peripheral

Intermediate – High Abdominal (including laparoscopic), carotid, peripheral artery PCI, endovascular aneurysm repair, head and neck, neurological, hip and spine, pulmonary, renal/liver transplant, major urological

Intermediate – Low Orthopaedic (knee), minor urological

Low Breast, dental, endocrine, eye, gynaecology, plastic

Boersma. Am J Med. 2005; 118: 1134-41

Fleisher. Circulation 2007; 116: e418-e500

Poldermans. Europ Heart J 2009; 30: 2769-2812

When to do an ECG

Recommendation Class

Risk factors + intermed/high risk surgery I

Risk factors and low risk surgery IIa

No risk factors + intermed/high risk surgery IIb (IIa*)

No risk factors + low risk surgery III

Poldermans. Europ Heart J 2009; 30: 2769-2812

*Fleisher. Circulation 2007; 116: e418-e500

Holter for syncope, presyncope, palpitation

When to have an echo

Recommendation Class

Symptoms I (IIa*)

Murmur I

High risk surgery & ≥ 3 risk factors IIa (III*)

High risk surgery & ≤ 2 risk factors IIb (III*)

Urgent surgery III

Low/intermediate risk surgery III

Poldermans. Europ Heart J 2009; 30: 2769-2812

*Fleisher. Circulation 2007; 116: e418-e500

• NB Echo usually normal if no symptom

+ normal ECG + normal examination

• ?? Screen using BNP

Severe aortic stenosis at surgery:

• Pulse pressure < 35 mmHg in 7%

• Systolic BP > 130 in 22-40%

• Normal carotid upstroke in 68%

Postmortem

• Systemic hypertension in 50%

Munt Am Heart J 1999; 137: 298-306. Lombard Ann Int Med 1987; 106: 292-8

Mautner Am J Cardiol 1993; 72: 194-8. Wren JRCP 1983; 17: 192-5.

• Symptomatic severe – need prior AVR

Consider balloon valvotomy/TAVI

• Asymptomatic + low/intermed risk surgery

Invasive monitoring, avoid arterial dilators

• Beware ‘moderate’ stenosis

Aortic stenosis

Mitral stenosis

• Rate control

• Balloon valvotomy if severe symptoms

Valve disease

• AR and MR do well if compensated:

– No symptoms and

– LVEF > 50% for AR and > 60% for MR

AHA Recommendations for noninvasive functional testing

Clinical Risk Factors:

IHD, CCF, CVA, insulin-treated Diabetes, Cr > 160 mmol/L, age > 70

Good functional capacity > 4 METs = can climb 2 flights or run for a bus

Fleisher. Circulation 2007; 116: e418-e500

LAD disease

REST PEAK STRESS

Coronary angiography

Recommendation Class

Acute coronary syndrome I

Angina unresponsive to medical therapy I

Stable & intermediate/high-risk surgery IIb

Stable & low risk surgery III

Poldermans. Europ Heart J 2009; 30: 2769-2812

All-cause death or infarction in vascular surgery DECREASE-V

Poldermans. JACC 2007; 49: 1763-9

Revasc + medical

Medical only

DSE or MPS if ≥ 3 risk factors

Revasc vs medical if ≥ 5 segments or ≥ 3 walls

Two died before vascular surgery

Intermediate risk patients having major vascular surgery

• Relative risk 1 or 2. n = 770

• 30 day outcome 2.3% with testing and 1.8% without testing

• Extensive ischaemia in 34 of 386 outcome 25% with revasc and 9.1% without

• Outcome related to heart rate < 65

Poldermans. JACC 2006; 48: 964-9

Effect of heart rate control

Feringa. Circulation 2006; 114: I-344-9

When to start oral beta-blockade

• Known CAD including positive functional test

• Vascular surgery or intermediate risk surgery and ≥ 1 risk factor

• Start beta-blocker early > 1 month

• Long-acting

• Titrate dose to heart rate 60-65

• Avoid hypotension (POISE)

Poldermans DECREASE 1. NEJM 1999; 341: 1789-94.

Devereaux. POISE. Lancet 2008; 371: 1839-47

Fleisher JACC 2006; 47: 2343-55

Key points

• Investigate and treat unstable angina, decompensated HF, arrhythmia, valve disease

• Consider investigation before high risk vascular surgery with > 1 risk factor esp if poor exertion

• Main protection medical therapy beta-blocker, aspirin and statin

• For the others investigation has no effect and delays surgery

www.researchechocardiography.com

Statins and aspirin

Statins

• Beneficial effect in all major non-cardiac surgery as well as vascular

• Avoid interruption (RR 4.6)

Aspirin

• Avoid interruption (RR 3)

Biondi-Zoccai. Europ Heart J 2006; 27: 2667-74

Functional testing

Recommendation Class

High risk surgery & ≥3 risk factors I

High risk surgery & ≤ 2 risk factors IIb

Intermediate risk surgery & poor function & ≥1 risk factor IIb

Low risk surgery III

Urgent surgery III

Poldermans. Europ Heart J 2009; 30: 2769-2812

Cardiac investigation before extracardiac surgery

• Aims: – To improve outcome after non-cardiac surgery

– Change operation e.g. conservative procedure, cancel operation

– Change management e.g. temporary pacing

– Screen for cardiac disease affecting long-term survival

• Avoid: – Investigation leading to poorer outcomes

– Delaying life-saving surgery

NatCEPOD 2001

• ‘Any asymptomatic murmur may indicate significant disease’

• ‘Whenever possible the anaesthetist of a patient with aortic stenosis should obtain a preoperative echocardiogram’

Problems after revascularisation

• Delay of index surgery

• Risks of cardiac surgery/PCI

• Need for clopidogrel after stenting

– 30 days bare metal

– One year drug-eluting

Coronary Artery Revascularization Prophylaxis trial before vascular surgery

McFalls. NEJM 2004; 351: 2795-2804

Performance of revised cardiac risk index score

Revised risk score

Number at risk Death (%) OR

≥ 3 969 3.6 11

2 3,380 1.7 5

1 28,892 0.7 2

0 75,352 0.3 1

Boersma. Am J Med. 2005; 118: 1134-41

Multivariate odds ratio of perioperative death

Type of surgery Age

Boersma. Am J Medicine 2005; 118: 1134-41

Whom to investigate

• Severe CAD

• Decompensated CCF arrythmia

• Murmur

• Vascular surgery with CAD or risk factors

• Intermediate risk surgery with poor activity and risk factors

Prevalence of valve disease

Three population studies n = 11,911

Ethnically diverse

Nkomo. Lancet 2006; 368: 1005-11

Community study n=16,501 Clinically indicated echoes in Olmsted County (90% white)

Meta-analysis of the effects of beta-blockade

Schouten. Coron Artery Didease 2006; 17: 173-9