Ondrej Lisy M.D. Ph.D. F.A.C.C.

Pts. with symptoms suggesting angina with intermediate or high pre-test likelihood of CHD

Pts. with acute CP after ACS exclusion

Within three months post-ACS for risk assessment

Known CHD and change in clinical status

After five years post CABG one time in asympt.

For newly dg. CHF or cardiomyopathy

For valvular heart disease – AS with low output

For active cardiac condition prior non-cardiac surgery

Screening of asymptomatic pts. (except high risk occupation)

Pts. with unstable symptoms

Pts. with low probability of CHD and atypical sx.

Pts. requiring emergency noncardiac surgery

For pts. who can attain an adequate level of exercise (5 min walk or 1-2 flights of stairs)-symptoms limited exercise testing is preferred

For pts. who are unable to exercise to sufficient cardiac workload – pharmacological stress testing

Modality based on factors:

- resting ECG

- clinical indication for performing the test

- body habitus

- history of prior revascularization

Acute MI within 2 days

Unstable angina

Uncontrolled arrythmias

Symptomatic severe valvular stenosis

Uncontrolled symptomatic CHF

Active endocarditis or myocarditis

Acute aortic dissection

Acute pulmonary embolism

Inability to obtain consent

Treadmill and stationary bicycle or arm ergometry

Bruce protocol – extensively validated; 3 min stages with steeper grade (Bruce 2 = 7 METS)

Modified Bruce – adds two low-workload stages to the beginning of Bruce

Naughton protocol – post MI and high risk pts.(Naughton 4 = 5 METS; 6 = 7 METS)

Testing for diagnostic purposes – avoid anti-ischemic medications (nitrates) and medications that slow heart rate (beta blockers, non-dihydropyridine Ca channel blockers) and certain antiarrhytmics (amiodarone, sotalol)

Target HR: 85% of maximal HR (220 – age)

SBP should rise with each stage of exercise while DBP falls or remains unchanged

0.3

1.3

5.0

0

2

4

6

8

10

Low Intermediate High

Score =

Duration (min Bruce protocol) –

(5x ST-seg deviation)(mm) –

(4x angina index)(0, 1, 2)

AnnualCV

mortality(%)

Mark DB: NEJM 325:849, 1991

(<-10)(-10 to +4)(5)

Severe chest pain

Near syncope; cyanosis

Fall in SBP (> 10 mmHg from baseline)

BP > 250/120

Marked ST segment depression or elevation

Increasing frequency of ventricular ectopy

High grade AV block

Sustained VT or Vfib

Achievement of 70% of MPHR for submaximal testing

Claudications, arthritis, deconditioning, pulmonary disease

Failure to achieve 85% MPHR

WPW pattern on ECG

V paced rhythm

LBBB

Greater than 1 mm ST-T depression

LVH with ST-T abnormalities

Digoxin use with ST-T abnormalities

Stress echocardiography (exercise or dobutamine)

Radionuclide stress myocardial perfusion imaging (SPECT or PET)

Stress cardiac magnetic resonance imaging

Main indications: ECG baseline abnormalities; inability to exercise; known CHD

Exercise or pharmacological

Detection of ischemia – development of new RWMAs; changes in end systolic volume, LVEF, LV cavity

Limitations: body habitus; LBBB; pacing

Goal: assessment of relative myocardial blood flow or perfusion between the resting and stressed states

Focus: intracellular myocardial extraction and retention of tracer (reversible vs. fixed defect)

Thalium-201 – cyclotron produced; uptake involving Na-K-ATPase pump directly proportional to coronary blood flow

Prolonged half life of 73 hrs limits allowable dose

Redistribution – continuous exchange between the myocyte and the extracellular compartment; post-stress imaging should begin within 15 min

Viability assessment

Technetium-99m labeled perfusion agents generator produced

Tc-99m sestamibi (Cardiolite) and Tc-99 tetrofosmin (Myoview) – lipophilic compounds with myocardial uptake proportional to flow with higher photon energy 140keV resulting in less photon attenuation and scatter

Minimal redistribution; injection during peak stress and at rest

Half life 6 hrs allows larger doses while keeping lower radiation exposure; high count rates -improved image resolution

PET uses radionuclides that decay by positron emission – relies on the detection of two 511keV gamma photons

Rubidium-82 (from strontium-82 generator) and N13-ammonia (from cyclotron)

Half life of Rb-82 is only 78 sec

PET imaging – equivalent, if not greater, overall sensitivity (84-93% PET vs 88% SPECT), specificity (81% PET vs 61-76% SPECT), and accuracy for the detection of CHD

Adenosine, dipyridamole and selective A2A receptor agonists – regadenoson (Lexiscan)

Increase coronary blood flow through their effects on adenosine A2A receptors

Presence of flow-limiting obstructive CHD leads to perfusion defects. The increase of blood flow is attenuated and there is relative reduction of radiotracer uptake.

Can be combined with low level of exercise

May be administered at peak exercise in pts. who fail to achieve target HR

Stimulates adenosine A2A receptors on vascular smooth muscle cells

Rapid injection over 10 sec (onset in 30 sec)

Half life of initial phase 2-4 minutes

Radioisotope (Tc-99m sestamibi) usually infused 10 sec after saline flush

Side effects (most resolves within 15 min): dyspnea, headache, chest pain, flushing

Dobutamine – synthetic catecholamine stimulates beta1-adrenergic receptors with the effect of increase HR and contractility

For pts. with vasodilators contraindications; on theophylline or who had caffeine within 12 hrs

Dobutamine with atropine results in hyperemia and significant increase in myocardial blood flow

Active bronchospastic airway disease

Hypotension

Sick sinus rhythm

High grade AV block

Unstable angina

Ventricular arrhythmia

Severe systemic hypertension

Prognostic SPECT39 Studies; 69,655 Patients

0.85

5.9

0

2

4

6

8

10

Normal PharmModerately-severely abnormal

Normallow risk

AnnualCD/MI

(%)

Shaw LJ and Iskandrian AE: JNC 11:171, 2004

AgeNonanginal pain Atypical angina Typical angina

Men Women Men Women Men Women

30 to 39 4 2 34 12 76 26

40 to 49 13 3 51 22 87 55

50 to 59 20 7 65 31 93 73

60 to 69 27 14 72 51 94 86

Values expressed as the % of patients with significant CHD on angiography. N. Engl J Med 1979

Sensitivity (%) Specificity (%)

Exercise ECG 45 to 61 70 to 90

Exercise stress echocardiography

70 to 85 77 to 89

Exercise stress SPECT 73 to 92 63 to 88

Pharmacologic stress echocardiography

72 to 90 79 to 95

Pharmacologic stress SPECT

88 to 91 75 to 90

Coronary CTA 93 to 99 64 to 90

2012 ACCF/AHA/ACP guidelines for dg. and management of stable CHD.

The estimate of pretest probability of CHD and clinical information can help to determine optimal diagnostic testing

Stress testing is the most useful in pts. with an intermediate pretest probability

In general, exercise ECG is preferred in pts. able to exercise

Stress testing with an imaging modality is typically performed in majority of pts. who are unable to adequately exercise, have baseline ECG abnormalities or have known CHD