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Diane Bild, MD, MPHScreening for Subclinical Atherosclerosis as a Strategy for CVD Prevention

FINANCIAL DISCLOSURE:None

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NoneSlide2

Screening for Subclinical Atherosclerosis as a Strategy for CVD Prevention

AHA Quality and Outcomes

May 21, 2010Diane Bild, MD, MPHAssociate Director, Prevention and Population Sciences ProgramDivision of Cardiovascular Sciences

The views expressed are not necessarily those of NHLBI

.Slide3

Prevent morbidity and mortality due to CVDIdentify disease before it becomes symptomatic.Prevent disease progression.

The Goals of Subclinical CVD ScreeningFootnote: “Screening” is a standardized population or case-finding approach, not an individualized strategy.Slide4

It may be costly.It may cause undue psychological stress.Coronary artery calcium detection requires CT scanning and radiation, which may induce cancer.

CT scans may uncover other subclinical disease (such as pulmonary nodules) that requires further work-up.Possible Harms of Subclinical CVD Screening Slide5

Hundreds of risk factorsCountless analyses from observational studiesRecent progress in modeling risk prediction, particularly with clinical relevanceDiscrimination

Calibration ReclassificationPredictionSlide6

Theoretical pathway from screening to prevention

http://lifebeat.pt/en2.php

Identify high risk

Further diagnosis

Treatment Rx

?

statins

? aspirin

?

antihypertensives

Long-term adherence

Risk loweredSlide7

1: No history of angina, heart attack, stroke, or peripheral arterial disease.

2: Population over age 75y is considered high risk and must receive therapy without testing for atherosclerosis.

3: Must not have any of the following:

Chol

>200 mg/dl, blood pressure >120/80 mmHg, diabetes, smoking, family history, metabolic syndrome.

4: Pending the development of standard practice guidelines.

5: High cholesterol, high blood pressure, diabetes, smoking, family history, metabolic syndrome.

6: For stroke prevention, follow existing guidelines.Slide8

How do we decide when screening is valuable?

Wilson JM. J R Coll Gen Pract 1968;16

Suppl 2:48 –57.Slide9

How do we decide when screening is valuable?

Wilson JM. J R Coll Gen Pract 1968;16

Suppl 2:48 –57.Slide10

Criteria for Evaluation of Novel Markers of Cardiovascular Risk

Hlatky, et al. Circulation 2009; 119:2408-2416.

?

?

CAC?Slide11

U.S. Preventive Services Task Force

GradeDefinitionSuggestions for Practice

AThe USPSTF recommends the service. There is high certainty that the net benefit is substantial. Offer or provide this service. B

The USPSTF recommends the service. There is

high certainty

that the net benefit is

moderate

or there is moderate certainty that the net benefit is moderate to substantial. Offer or provide this service.

C

The USPSTF recommends against routinely providing the service. There may be considerations that support providing the service in an individual patient. There is at least

moderate certainty that the net benefit is small

.

Offer or provide this service only if other considerations support the offering or providing the service in an individual patient. Slide12

U.S. Preventive Services Task Force

GradeDefinitionSuggestions for Practice

DThe USPSTF recommends against the service. There is moderate or high certainty that the service has no net benefit or that the harms outweigh the benefits.Discourage the use of this service

I

Statement

The USPSTF concludes that the current evidence is

insufficient to assess the balance of benefits and harms of the service. Evidence is lacking, of poor quality, or conflicting, and the balance of benefits and harms cannot be determined.

Read the clinical considerations section of USPSTF Recommendation Statement. If the service is offered, patients should understand the uncertainty about the balance of benefits and harms.Slide13

Condition

ExplanationGradeAbdominal aortic aneurysm (2005)

One-time screening for AAA by ultrasonography in men aged 65 to 75 who have ever smoked. B

No recommendation for or against screening for AAA in men aged 65 to 75 who have

never smoked

.

C

The USPSTF recommends against routine screening for AAA in

women

.

D

CV screening recommendations per USPSTFSlide14

Condition

ExplanationGradeCarotid artery stenosis (2007)

Recommends against screening for asymptomatic carotid artery stenosis in the general adult population. D

Peripheral artery disease (2005)

The USPSTF recommends against routine screening for peripheral arterial disease.

D

CV screening recommendations per USPSTF, continuedSlide15

Condition

ExplanationGradeCoronary heart disease (2004)Recommends against routine screening with resting electrocardiography (ECG), exercise treadmill test (ETT), or electron-beam computerized tomography (EBCT) scanning for coronary calcium for either the presence of severe coronary artery

stenosis (CAS) or the prediction of coronary heart disease (CHD) events in adults at low risk

for CHD events.

D

Insufficient evidence to recommend for or against routine screening with ECG, ETT, or EBCT scanning for coronary calcium for either the presence of severe CAS or the prediction of CHD events

in adults at increased risk

for CHD events.

I

CV screening recommendations per USPSTF, continuedSlide16

Condition

ExplanationGradeRisk assessment, nontraditional risk factors (2009)Evidence is insufficient to assess the balance of benefits and harms of using the nontraditional risk factors discussed in this statement to screen asymptomatic men and women with no history of CHD to prevent CHD events

I

CV screening recommendations per USPSTF, continued

The nontraditional risk factors included in this recommendation are high-sensitivity C-reactive protein (

hs

-CRP), ankle-brachial index (ABI), leukocyte count, fasting blood glucose level, periodontal disease, carotid

intima

-media thickness (carotid IMT), coronary artery calcification (CAC) score on electron-beam computed tomography (EBCT),

homocysteine

level, and lipoprotein(a) level.Slide17

Condition

ExplanationGradeLipid disorders in adults (2008) - MenThe U.S. Preventive Services Task Force (USPSTF) strongly recommends screening men aged 35 and older for lipid disorders.

 The USPSTF recommends screening men aged 20 to 35 for lipid disorders if they are at increased risk for coronary heart disease.

A

B

Lipid disorders in adults (2008) – Women at increased risk

The USPSTF strongly recommends screening women aged 45 and older for lipid disorders if they are at increased risk for coronary heart disease.

The USPSTF recommends screening women aged 20 to 45 for lipid disorders if they are at increased risk for coronary heart disease.

A

B

CV screening recommendations per USPSTF, continuedSlide18

Condition

ExplanationGradeLipid disorders in Adults --Young Men and All Women Not at Increased Risk

The USPSTF makes no recommendation for or against routine screening for lipid disorders in men aged 20 to 35, or in women aged 20 and older who are not at increased risk for coronary heart disease.

C

Blood pressure

The U.S. Preventive Services Task Force (USPSTF) recommends screening for high blood pressure in adults aged 18 and older.

A

CV screening recommendations per USPSTF, continuedSlide19

Level of evidence A: recommendation based on evidence from multiple randomized trials or meta-analysesLevel of evidence B: recommendation based on evidence from a single randomized trial or nonrandomized studiesLevel of evidence C: recommendation based on expert opinion, case studies, or standards of care

The ACC/AHA guidelines grading scheme – Results for CACTricoci

, et al. JAMA 2009;301:831-841.Slide20

CAC improves CHD risk prediction, calibration, and classification

Polonsky, et al. JAMA 2010;303:1610-16.Slide21

Efficacy of cholesterol-lowering treatment:prospective meta-analysis of data from

90,056 participants in 14 randomised trials of statins

Source: Cholesterol Treatment Trials Collaborators. Lancet 2005:366:1267–78

“Treatment better”

~25% risk reductionSlide22

Randomized, placebo-controlled trial of cholestyramine

Lipid Research Clinics Program. JAMA 1984;251:351-64.Slide23

Published in 1967

N=143Randomized placebo-controlled trial of diuretics in severe hypertension

VA Cooperative Study Group on Antihypertensive Agents. JAMA 1967;202:116-21.Slide24

We have come only so far . . .Slide25

Call for trials of imaging

Douglas, et al. Outcomes Research in Cardiovascular Imaging: Report of a Workshop Sponsored by the National Heart, Lung, and Blood Institute. JACC Cardiovasc

Imaging 2009;2:897-907.Slide26

Guidelines may need to be changed due to:Emergence of new evidenceChanges in disease prevalence

Consideration of new risk groupsDevelopment of new therapiesChanges in the cost of treatmentRe-evaluating Screening GuidelinesSlide27

Goals are laudable; some candidate screening markers have promising characteristics.Harms of screening need to be carefully considered, especially for coronary artery calcium detection.

Few screening targets in cardiovascular disease prevention are deemed beneficial -- most notably, BP and lipids.Much work has been performed in estimating prediction; little in estimating outcomes.Any screening guidelines need periodic re-evaluation.Summary – Subclinical CVD Screening