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CAD

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cbenitesch
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09/03/06 - 04:54 PM

What´s the test with the best preditive value for detecting CAD?

Sea_gull
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09/03/06 - 05:12 PM

For Detection of CAD two types of test are done

Non invasive
1. Exercise treadmill test
2. Stress imaging tests
Invasive
1. Angiography

Among them increasing PPV is

Exercise treadmill test < Stress imaging studies < Coronary angiography

So Coronary angiography is the "BEST "

GL

icemaiden
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09/03/06 - 06:21 PM

just to add, PET is the best for assessment of myocardial viability.
ice.

cbenitesch
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09/03/06 - 06:59 PM

Non invasive stress tests have the best PV for CAD!... remeber the order of thinking!---> think CHEAP first! wink

study_ing
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09/04/06 - 06:16 AM

i wud divide 'detecting' into screening and diagnostic.

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frank100
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09/04/06 - 06:42 AM

ekg

Sea_gull
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09/04/06 - 09:10 AM

frank100 wrote:
ekg

Majority of Angina patients have "normal EKG" at rest. I think so ,

GL

GDS2008
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09/04/06 - 09:28 AM

Well....the question here is "what is the test with the best predictve value (positive PV I would assume) for detecting CAD. We know that PPV depends on two things: 1) Sensitivity of a test 2) Prevalence of the disease in whom the test is conducted. With the prevalence as a constant (we will do all the tests for detecting CAD on a single group of patients with the same prevalence), the only thing that it will depend on now is the sensitivity of the test. In other words, this question can be answered by lokking for a test which has the highest sensitivity (not specificity) for detecing CAD. By CAD, we mean stable angina and acute coronary syndromes. While non invasive tests (stress testing and others) are good screening tests none of them are 100% sensitive. The only test that meets thsi criteria is "Aoronary angiography". I am not syaing that this should be doen "initially" but the answer to this questions i.e. with the best PPV is Coronary angiography.
Just to add to frnak's post -- EKG is only 75% sensitive in picking up angina. therefore, it cannot have the best PPV.

Sea_gull
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09/04/06 - 09:49 AM

Thanks GDS2008.This is what I think that Coronary Angiography has the best PPV.But I would like to differ on one point.

PPV does depend on PREVALENCE.But I think it does not depend on SENSITIVITY.

GL

GDS2008
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09/04/06 - 10:05 AM

#10

PPV decreases with increasing sensitivity, but increases with increasing specificity. (due to change in False +ves). I meant specificty in the last post. Coronary angiogram is the msot specific test for CAD. Thanks!

Sea_gull
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09/04/06 - 10:27 AM

#11

GDS2008 wrote:
PPV decreases with increasing sensitivity, but increases with increasing specificity. (due to change in False +ves). I meant specificty in the last post. Coronary angiogram is the msot specific test for CAD. Thanks!

Dear

Now see this statement contradicts your previous one.If increase in sensitivity decreases the PPV,then angiography being very sensitive should have least PPV and stress tests having decrease sensitivity should have high PPV.(According to your logic)

I am not very good on this confusing biostatistics.I feel probably you are referring to screening test diagrams.In which we change the Cut off value and consequently sensitivity and PPV both are affected.But I think our point of discussion is different.

What do you say??

GDS2008
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09/04/06 - 10:40 AM

#12

Dear Sea_gull, did I not say in my last post that I meant "specificity" (not sensitivity) in the original post. Coronary angiogram has about 100% specificity but about 70% sensitivity (as many healthy individuals also have some narrowingm which can be seen right from childhood) and therefore it is never used as a screening test. So it is the specificity that I was referring to and with increasing specificty, the PPV aslo increases. I am sorry about the confusion due to my original psot where I wrote sensitivity, when I actually wanted to say specificity.

Also, EKG is only 75% SPECIFIC in picking up CAD.
Thanks! smiling face

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