Controversies in Myocardial Perfusion Imaging

Controversies in Myocardial Perfusion Imaging

Thomas H. Hauser, MD, MMSc, FACC

Director of Nuclear CardiologyBeth Israel Deaconess Medical Center

Instructor in MedicineHarvard Medical School

Boston, MA

A major teaching hospital of Harvard Medical School

Harvard Medical School

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Outline

• Women• Diabetes• Non-Cardiac Surgery• Choice of Stress Imaging Modality


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Outline



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Case 1

68 year old woman with a history of hypertension and dyslipidemia presents with a long history of exertional dyspnea. Her physical examination is normal.

What test do you order?A. Resting echocardiogramB. ETTC. Nuclear imagingD. Cardiac catheterization


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Women and Cardiovascular Disease

• More than 500,000 women will die this year from CAD, stroke and other cardiovascular diseases– More women die from CVD than men

• CAD is the #1 killer of women– More than the next 7 causes of death combined

AHA Statistics


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AHA Statistics


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• CAD risk factors are the same for men and women• Women are more likely to present with atypical

symptoms or have silent events• Physicians are less likely to consider a diagnosis

of CAD in women

Fossati et al, in Nuclear Cardiology, 2004


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Women: Inappropriate Triage

Pope et al, N Engl J Med 2000;342:1163-70


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Women: Less Use of Diagnostic Tests

Roger et al, JAMA. 2000;283:646-652


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Women: ETT Alone is Inadequate

Nasir et al, Arch Intern Med. 2004;164:1610-1620

Specificity80%

Sensitivity44%


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Women: Reasons for Poor Performance

• Peak HR and BP are lower • Magnitude of STD is less• Chest wall shape differs • Vascular reactivity differs• Prevalence of disease is lower


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Women: MPI Diagnosis

Amanullah et al, JACC 1996;27:803


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Women: MPI Risk Stratification

Berman et al, J Am Coll Cardiol 2003;41:1125–33


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Case 1




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Case 1




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Case 1: Raw Data


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Case 1: Attenuation Map


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Case 1: Slices


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Case 1: Attenuation Correction


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Case 1: Gated Images


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Case 1: Quantitative Data


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Difficulties in Imaging Women

• Breast attenuation• Small heart size


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Case 1

• She exercised for 4.5 minutes of a modified Bruce protocol

• Peak HR of 119 (78% predicted maximal)• Peak BP 230/92• Typical angina with stress• Ischemic ECG changes


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Case 1

Her study is interpreted as abnormal. What do you do now?

A. Begin a trial of medical therapy without further evaluation

B. Refer for cardiac catheterization for definitive diagnosis and potential revascularization


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Women: Referral for Evaluation and Treatment

Hachamovitch et al, JACC 1995:1457


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• CAD is highly prevalent among women• Women can present with atypical symptoms• ETT alone is controversial for evaluation of CAD• Nuclear imaging may be preferable for the evaluation

of women for both diagnosis of CAD and determination of prognosis

• Treatment of CAD is not gender-specific


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Outline



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Case 2

A 58 year old man with type 2 diabetes visits his internist because he is worried about his CAD risk. He is taking a statin for dyslipidemia (last LDL 90). His BP is 130/80. The internist should:

A. Start aspirin and an ACE-inhibitorB. Order an ETTC. Order an ETT with nuclear imagingD. Reassure him that he is at low risk


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Diabetes and Cardiovascular Disease

• Coronary artery disease is major complication of diabetes– Independent effect of diabetes

– In patients with type 2 diabetes, obesity, hypertension and dyslipidemia also contribute

• The prevalence of CAD is estimated at up to 55% among patients with diabetes– More than 20% may have silent ischemia

• Delayed presentation

ADA, Diabetes Care 1998;21:1551Wackers et al, Diabetes Care. 2004 Aug;27(8):1954-61


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Evaluating CAD in Diabetics

ADA, Diabetes Care 1998;21:1551


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Requirements for a Useful Screening Test

• Relatively high disease prevalence– CAD in 55% in diabetics

• Asymptomatic phase of the disease– Silent ischemia in 20%

• Available test that can detect the disease during the asymptomatic phase– Nuclear imaging

• Treatment that alters the natural history when preferentially applied during the asymptomatic phase– Lipid lowering, aspirin, ACE-inhibitor, β-blocker,

revascularization


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Asymptomatic Diabetics

ADA, Diabetes Care 1998;21:1551


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Haffner et al, N Engl J Med 1998;339:229-34


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Haffner et al, N Engl J Med 1998;339:229-34


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Diabetes = CAD

• “Some persons without established CHD will have an absolute, 10-year risk for developing major coronary events (myocardial infarction and coronary death) equal to that of persons with CHD, i.e., >20 percent per 10 years. Such persons can be said to have a CHD risk equivalent.”– Diabetes

– Non-coronary atherosclerotic disease

– Multiple risk factors

NCEP-ATP III, Circulation, Dec 2002; 106: 3143


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Diabetes = CAD

• Patients with diabetes should be treated to the same lipid goals as those with CAD– Diabetes alone is high risk

• LDL goal of <100 (can consider a goal of <70)

– The combination of diabetes and CAD is very high risk• LDL goal of <70

NCEP-ATP III Update, Circulation, Jul 2004; 110: 227 - 239


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Diabetes = CAD

• Aspirin therapy– Age >40

• Hypertension– Goal BP <130/80

– Treatment with two or more agents• ACE-inhibitor

• Revascularization…– Mortality benefit proven only in those with 3VD

ADA, Diabetes Care 2004;27(S1):S15


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Case 2




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Case 2




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Case 2

• The patient’s internist, having recently read an editorial advocating screening MPI for patients with diabetes, refers him for ETT with nuclear imaging.


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Case 2


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Case 2

• He exercised for 7 minutes of a Bruce protocol• Peak HR of 140 (86% predicted maximal)• Peak BP 178/80• No symptoms• No ECG changes


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Case 2

The study is interpreted as normal. Based on this data, the patient is now:

A. Low risk

B. Intermediate risk

C. High risk

D. Very high risk


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Risk Stratification in Diabetics

Giri et al, Circulation. 2002;105:32-40


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Case 2


A. Low risk


C. High risk

D. Very high risk


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Case 2


A. Low risk


C. High risk

D. Very high risk


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• Coronary artery disease is common in diabetes and results in significant mortality and morbidity

• Diabetics without CAD have the same risk for adverse events as non-diabetics with CAD

• Screening diabetics for CAD is controversial• The prognosis for diabetics with an abnormal MPI

result is worse than for patients without diabetes• A normal MPI result in diabetes does not imply

low risk


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Outline



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Case 3

A 64 year-old man with history of diabetes is referred to you for evaluation prior to elective repair of an abdominal aortic aneurysm. He feels well and plays golf every weekend without symptoms. He has had no prior cardiac evaluation. What do you recommend?

A. No further testing needed

B. Resting echocardiogram

C. Nuclear imaging with dipyridamole stress

D. Cardiac catheterization


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Peri-Operative Cardiac Complications

• 30 million patients undergo procedures that require general anesthesia each year.

• 10 million either have CAD or have a significant risk of CAD

• 1 million have cardiac complications– $20 billion

Mangano et al, NEJM 1995;333:1750


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Operative Risk of Death or MI

Ashton, C. M. et. al. Ann Intern Med 1993;118:504-510


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Determining Operative Risk

• Rapid determination of those that do not need

testing• Patient

– Clinical risk predictors– Exercise tolerance

• Procedure– Procedural risk

• +/- Testing

Eagle et al, 2002 AHA/ACC Guidelines


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No Testing Needed


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Patient: Clinical Risk Predictors



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Major Clinical Predictors


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Patient: Clinical Risk Predictors


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Intermediate Clinical Predictors


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Patient: Exercise Tolerance



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Intermediate Risk Predictors


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The Procedure



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Minor Risk Predictors


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Intermediate Risk Predictors


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Risk Stratification with Nuclear Imaging

D ip yrida m o le-T h a lliu m -2 01

C a nce led6 .4 %

E ve n t R a te1 8 % (N = 5 2 3)

N o R e va sc

E ve n t R a te5 .9 % (N = 5 7)

R e va sc

R e vers ib leD e fe c t

E ve n t R a te1 1 % (N = 3 4 7)

F ixe d D e fe ct

E ve n t R a te3 .2 % (N = 4 3 0)

N o rm al

N o R e ve rs ib leD e fe c t

N = 1 ,9 94

Shaw et al. JACC 1996;27:787


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Case 3







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Case 3







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Case 3


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Case 3

He is referred for cardiac catheterization and found to have an 80% middle LAD stenosis. The interventionalist should:

A. Do nothing

B. Refer him for CABG

C. Stent the lesion

D. Perform PTCA


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Reducing Peri-Operative Risk

• Revascularization– CABG

– PTCA

– Stents

• Medical therapy– β-Blockers


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CABG Reduces Mortality

Eagle et al, Circulation. 1997;96:1882-1887


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…Or Does It?

McFalls et al. NEJM 351 (27): 2795


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… Or Does It?


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PTCA Reduces Adverse Events…

Posner et al, Anesth Analg 1999;89:553–60


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PTCA Increases Events Within 30 Days

Posner et al, Anesth Analg 1999;89:553–60


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Stents Increase Mortality

• 40 consecutive patients who underwent surgery within 6 weeks of PCI

• 8 deaths (20%)– Antiplatelet agents held in 7

• 11 episodes of major bleeding (28%)


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β-Blockers Reduce Mortality

Mangano et al, NEJM 1996; 335:1713-1721, N = 192 with CAD or RF


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Poldermans et al. NEJM 341 (24): 1789


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Poldermans et al. NEJM 341 (24): 1789


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Unproven Benefit

• Statins• ACE-inhibitors

• Nitrates• Calcium channel blockers


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Case 3


A. Do nothing


C. Stent the lesion

D. Perform PTCA


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Case 3


A. Do nothing


C. Stent the lesion

D. Perform PTCA


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Non-Cardiac Surgery

• Patients with CAD or CAD risk factors frequently undergo non-cardiac surgery

• Most patients do not need further evaluation prior to their procedure

• Selected patients with risk factors and/or poor exercise tolerance may require risk stratification with nuclear imaging

• CABG and β-blockers reduce peri-operative mortality and morbidity

• PTCA and stents increase peri-operative mortality and morbidity


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Outline



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Nuclear Imaging vs. Echocardiography

• The relative test performance between nuclear imaging and echocardiography is unknown– Nuclear imaging probably more sensitive

– Echocardiography probably more specific

• Nuclear imaging is more expensive– Nuclear perfusion at rest and with stress, with gating

• $739

– Echo at rest and with stress, with doppler and color• $358


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Echo is Better

Kuntz, K. M. et. al. Ann Intern Med 1999;130:709-718


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Is Echo Better



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Cost Effectiveness of Nuclear Imaging

Hachamovitch et al. Circulation 2002;105:823


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Prevalence of CAD



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Cost Effectiveness of Nuclear Imaging

Hachamovitch et al. Circulation 2002;105:823


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Choice of Stress Imaging Modality

• Nuclear imaging is more expensive than echocardiography

• The increased expense of nuclear imaging is probably justified


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Summary

• Women– CAD is prevalent in women– Nuclear imaging may be preferable for the evaluation of women

for both diagnosis of CAD and determination of prognosis

• Diabetes– Diabetes = high CAD risk– Screening for CAD with nuclear imaging is controversial

• Non-Cardiac Surgery– Nuclear imaging is a valuable tool for risk stratification– β-blockers reduce peri-operative mortality

• Choice of Stress Imaging Modality– No clear answer

Documents

Controversies in Myocardial Perfusion Imaging