Cardiac Testing: The Bottom Line

Craig Butler MD, MSc, FRCPC

September 29 2018

Outline

• Testing Overview

• Bottom line for Coronary workup

– CV Risk Assessment

– Rule in vs. rule out

• Bottom line for Myopathic workup

- When is MRI needed

CAD Testing Overview

1) Invasive angiography

2) CT angiography

3) (MR angiography)

1) MRI

2) Stress echo

3) Nuclear

1) MRI

2) Echo

3) CT

4) Nuclear

Exercise Stress

1) EKG

2) echo

3) nuclear

Pharmacologic

Stress

1) Dipyridamole

a) nuclear

b) MRI

2) Dobutamine

a) echo

b) MRI

c) nuclear

Ischemia

Guiding Principal 1 - Rational Approach to Investigation

National post Feb 12 2016

Hamilton Spectator Feb 11 2016

Chest Pain Algorithm

Chest PainCreate a

Differential

diagnosis

Rule in

Rule out

Medical or

Surgical

Management

Gather

Information

about CC

(i.e. HPI, PE)

Pre Test Probability Diagnostic Testing

Chest Pain Work up

Typicality of Pain

Pre-test Probability

Patient CV Risk Rule in Disease

Rule out Disease

Chest pain

54 year old man

– DMII

– smoker

– prior TIA/Stroke

– Sedentary

– central abdominal obesity

– Clinic visit with atypical chest pain.

68 year old man, no risk factors, tennis 3-5x/week Clinic visit room with atypical chest pain

Contributing Risk Factors

Interheart Lancet 2004

CV risk Factor Risk

Dyslipidemia 3.3

Smoking 2.9

Psychosocial 2.7

Diabetes 2.4

Hypertension 1.9

WHR 1.1-1.6

Exercise (>4hr/wk) 0.9

Alcohol (>3/week) 0.9

Diet 0.7

Summarizing Risk

• Framingham Risk

• FRS – CVD

• ATP III – FRS – CHD

• Reynolds Risk Score

• AHA-ACC-ASCVD

Ten year vs. Life time risk?

Overestimation of Risk

• Risk Models are generally heavily weighted to age

1900 2015

Diabetes

Lipids

Sedentary

Obesity

Smoking

Age

Diabetes

Lipids

Sedentary

Obesity

Smoking

Age

?

+

Risk Refinement

• CAC adds to FRS and is better than:

– Carotid IMT

– Brachial Flow

– C-reactive protein

– ABI

Yeboah JAMA

2012

FRS +

CAC

CV risk: Reclassificaton

21%

30%

Elias-Smale JACC 56, 1407

Make Our Diet Great Again?

Thompson Horus Study JACC CVI 4;315

Thompson Lancet 2013

• 137 mummies (34% had vascular Calcium)– Ancient Egyptian– Ancient Peruvians– Ancestral Peubloans– Aleutian Islands

Chest Pain Work up

Typicality of Pain

Pre-test Probability

Patient CV Risk Rule in Disease

Rule out Disease

Typicality of Pain

1) Worse with activity

2) Relieved with Rest of Nitro

3) Retrosternal in location

1/3 = non-anginal

2/3 = atypical

3/3 = typical angina

Pre-test prob of Obstructive CAD

Cheng Circulation 2011

Chest Pain Work up

Typicality of Pain

Pre-test Probability

Patient CV Risk Rule in Disease

Rule out Disease

Chest Pain Work up

Typicality of Pain

Pre-test Probability

Patient CV Risk Rule in Disease

Rule out Disease

Ruling in CAD

• Angiogram

– Would you send for CABG if necessary?

• Trial of Medical Therapy

Meta-analysis of PCI vs OMT in Ischemic CAD

JAMA Int Med2014; 172 (4):312

Death MI

Unplanned Revasc Angina in follow-up

What’s at stake with Stable Angina

• Uncertainty remains about which subgroup of stable angina patients receive prognostic benefit of PCI

• Principal therapeutic goal is to:

– reduce symptoms

– treat risk factors

• Peri-procedural risk is an important offset of benefit

– Age - Lung disease - GFR

– PVD - history of CHF

Peterson et al JACC 2010;

55(18)

Chest pain Pre-test probability

Typicality of Pain

Pre-test Probability

Patient CV Risk Rule in Disease

Rule out Disease

Guiding Principle 2 – test Utility

Positive test resultTest with 90% sensitivity and 90% specificity

Basic Principles of Diagnostic test use and interpretation. Nicoll et

al.

Rule in

Rule

out

GP 2 Test Utility –Likelihood ratio

EST: LR+ = 3, LR-=0.5

MIBI: +LR=3, -LR= 0.18

CCTA: LR+ = 7, LR-=0.06

Exercise Echo: LR+ = 8, LR – 0.2

CMRI: LR+= 4, LR-= 0.12

Trop: LR+ = 16, LR-=0.07

Banerjee IJCP 2012;66(5)

De Jong, Euro Rad 2012;22(9)

McArdie JACC 2012; 60(18)

Picano CVUS 2008;6

+LR -LR

EST 3 0.5

MIBI 3 0.2

CMRI 5 0.1

DSE 6 0.2

RbPET 6 0.1

ESE 8 0.2

CCTA 7 0.07

Troponin 16 0.07

2

4

Guiding Principal 3 – Our judgement is better than we think• 400K patients without

known CAD

• ~40% stenosis >50%

• Odds ratio for + NIT = 1.3

RiskRisk +

symptoms

Risk +Symptoms

+ NIT

Patel NEJM 2010

Ruling Out Ischemia

FunctionalAnatomic

CT angiogram

• Pre-test probabailty

• Test Accuracy

• Specific patient variables

Exercise(Echo,EKG)

Pharmacologic

(Echo,Nuc,MRI)

Functional Ischemic TestingStress Sign of Ischemia

EKG Wall motion Perfusion

Exercise EST ESE SPECT

DobutamineDSE/DSMRI Nuclear

MRI

VasodilationNuclear

MRI

Exercise Stress Test

Pro• physiologic

• Non-invasive

• Relatively inexpensive

• Readily Available!

Con• Sens = Spec = ~65%

• MSK contraindications

SPECT Perfusion

ProAccessible

Prognosis data

Sensitive

ConTwo day test

High radiation dose

Prone to artifact

Reader experience

Vasodilator Stress

+ + +++ +

Rubidium PET

Pro• Better specificity than

Spect

• One day test

• Absolute blood flow

Con• Radiation

• Accessibility

• No viability

RadiationTest Dose (mSv)

MIBI 18 – 24

6 - 12

Rubi PET 3-5

Barium Enema 7

Cardiac Cath 2 – 10

Chest CT ~8

Virtual Colon 8-14

Coronary CT (64) 8-10

Dual source 128 2-4

CMR

Pro• No radiation

• Safe

• Accurate perfusion

• Function

• Viability

Con• Accessibility

• Cost

CMR vs SPECT

MR IMPACT EHJ 2008

Stress Echo

Pro

• Physiologic

–Exercise

–Change in function

Con

• Access/wait times

• Expertise

Coronary CT angiogram

Coronary CT angiogram

Pro• Sensitive

• Prognostic data

Con• Radiation

• Heart rate control

• Previous revasc

Scot-Heart

• N=4146

• Referred to chest pain clinic

• 18-75 yrs old

• Standard care + CCTA vs Standard care alone

• Employing CCTA– Increased the certainty

of diagnosis

– Increased diagnosis of CHD

– Decreased frequency of Diagnosis of Angina due to CHD

– Decreased use of anti-anginals

– Reduced planned investigations

Scot Heart Lancet 2015

Coronary CT - Evidence in Stable Angina

• Scot-Heart (n=4146)

– Standard Care + CCTA vs. Standard Care

– Improved Clarity of Diagnosis

– Reduced number of tests required

– Trend to increased revascularization

– Increased preventative medication

– Reduced anti-anginal medication

– Trend to reduced events

Scot Heart NEJM 2018

Scot Heart Lancet 2015

2016 NICE guideline update

Myopathy Workup

• Heart failure reduced ejection fraction (HFrEF)

– Ischemic

– Idiopathic

– Toxin

– Familial

– Other

• Heart Failure preserved ejection fraction (HFpEF)

– Hypertensive

– Hypertrophic

– Infiltrative

Echo is first line and sufficient in most

instances

When to use MRI

• Ischemic

– Diagnostic Confirmation• Mimics

– Myocarditis?

– Tako-Tsubo

– Viability pre-revasc

– Perfusion

• Infiltrative

– Amyloidosis

– Fabry’s disease

– Iron Overload

– Sarcoidosis

– (Hypertrophic)

Bottom Line

CCoronary Artery Disease

Myocardial Disease

Valvular Disease

No Known Disease = CT angioKnown Disease = Nuclear or stress echo

Echo at reputable instituteMRI for Viability or HFpEF

Echo at reputable institute

Questions?