Thread by @AmitGoyalMD, What do you tell:A 52 yo F w/ active smoking, DM, HLD, [...]

What do you tell:

A 52 yo F w/ active smoking, DM, HLD, and HTN
who p/w DOE & chest pain with evening walks
whose LHC is negative for stenoses,
& CXR, PFTs, TTE are all unrevealing?

"Don’t worry, you'll be fine…here's a xanaz", right?

WRONG….let's dig deeper. #tweetorial

What do you tell:A 52 yo F w/ active smoking, DM, HLD, and HTNwho p/w DOE & chest pain with evening walkswhose LHC is negative for stenoses,& CXR, PFTs, TTE are all unrevealing?"Don’t worry, you'll be fine…here's a xanaz", right?WRONG….let's dig deeper. #tweetorial

2/13

What's the next step to evaluate her classic angina?

3/13
Running behind on a busy clinic...why dig deeper

Well, coronary angiography only "sees" a tiny portion of the coronary tree.

Beyond the epicardial horizon, there's a vast network of pre-arterioles, arterioles, and capillaries.

https://www.jacc.org/doi/full/10.1016/j.jcmg.2019.09.006?_ga=2.41049127.449998764.1609185083-652351969.1608141845

3/13Running behind on a busy clinic...why dig deeperWell, coronary angiography only "sees" a tiny portion of the coronary tree.Beyond the epicardial horizon, there's a vast network of pre-arterioles, arterioles, and capillaries. https://www.jacc.org/doi/full/10.1016/j.jcmg.2019.09.006?_ga=2.41049127.449998764.1609185083-652351969.1608141845

4/13
Coronary Microvascular Disease (CMD) = disease of these smaller vessels.

Normally, small resistance vessels regulate blood flow.

Abnormalities in these compromise blood flow:

Structural

Functional

Extravascular

https://www.jacc.org/doi/full/10.1016/j.jacc.2018.09.042
https://www.ahajournals.org/doi/10.1161/CIRCULATIONAHA.118.031373

4/13Coronary Microvascular Disease (CMD) = disease of these smaller vessels.Normally, small resistance vessels regulate blood flow. Abnormalities in these compromise blood flow:StructuralFunctional Extravascular https://www.jacc.org/doi/full/10.1016/j.jacc.2018.09.042 https://www.ahajournals.org/doi/10.1161/CIRCULATIONAHA.118.031373

5/13
Ok, I get it. Coronary angio's can't see the vast majority of the coronary tree and CMD can exist without epicardial CAD.

But why is this so important

Because: CMD w/o obstructive epicardial CAD --> a/w

4x mortality

5x MACE

https://www.ahajournals.org/doi/epub/10.1161/JAHA.119.014954

5/13Ok, I get it. Coronary angio's can't see the vast majority of the coronary tree and CMD can exist without epicardial CAD.But why is this so importantBecause: CMD w/o obstructive epicardial CAD --> a/w4x mortality5x MACE https://www.ahajournals.org/doi/epub/10.1161/JAHA.119.014954

6/13
Fine, CMD is important to look for, but how if we can't see these vessels?

There are invasive and noninvasive tools.

In all of these, look at flow (velocity or tissue perfusion) at rest and stress.

Stress / Rest = cor flow reserve (CFR) = evaluates entire coronary tree.

7/13
PET with absolute myocardial blood flow is most well studied for evaluation of CMD.

Measure absolute myocardial blood flow (MBF) at rest and stress.

MBF@stress / MBF@rest = CFR

8/13
Let’s get back to our patient with chest pain, risk factors, and a negative cath.

FIRST, reassess the pre-test prob (PTP) of coronary disease.

Neg LHC & low PTP --> likely true negative
Neg LHC & high PTP --> likely false negative --> dig deeper!

https://academic.oup.com/eurheartj/article/41/3/407/5556137

9/13
Despite a negative LHC, our patient still has a significant pre-test prob.

Pearl: women are more likely to have coronary microvascular disease.

So: let's dig deeper for coronary microvascular disease!

https://academic.oup.com/eurheartj/article/41/3/407/5556137

9/13Despite a negative LHC, our patient still has a significant pre-test prob.Pearl: women are more likely to have coronary microvascular disease.So: let's dig deeper for coronary microvascular disease! https://academic.oup.com/eurheartj/article/41/3/407/5556137

10/13
You get a rest/stress PET and…

…the global CFR is 0.88, far less than the diagnostic threshold of 2.

This can be from any combination of epicardial & microvasc CAD.

But for her, with negative LHC and low CFR, we've diagnosed CMD!

What’s the treatment?