PE in Pregnancy?

[turkeyjerky]

We were talking about this in conference today and there were some minor disagreements, so I was wondering how you like handle it at your shops. If low risk do you still use d-dimer? If so, do you use the typical normal range, or does your lab have pregnancy-corrected values? Then what, do you go for bilateral leg US's, followed by rx or d/c, or do you proceed w/ more imaging?

How about high risk; routinely get leg US's prior to chest imaging? Then what imaging do you go for: CTPA, knowing it's higher radiation for the fetus, or V/Q, given that it's lower overall, especially for the breast.

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[WilcoWorld]

1st, radiation: My understanding is that VQ exposes the fetus to more radiation than CTPA, because the radioactive agent is extreced in the urine. Add to that the frequency with which VQ doesn't answer your question and my preference is CTPA.

HOWEVER, I would argue that most pregnant women need neither. If a pregnant patient has a DVT then it's heparin (LMWH) for the duration of the preganancy. If there is no DVT, and the patient has normal vitals (including O2 sat) then you could discharge and have the patient get serial US of the legs with instructions to return for new or worsening symptoms.

That leaves only the unstable pregnant patient who needs chest imaging, and those patients are quite rare.

As for d-dimer, some advocate adjusting up, based on trimester. I personally haven't seen enough convincing literature to adopt this practice myself, however.

 

[Tiger26]

1st, radiation: My understanding is that VQ exposes the fetus to more radiation than CTPA, because the radioactive agent is extreced in the urine. Add to that the frequency with which VQ doesn't answer your question and my preference is CTPA.

HOWEVER, I would argue that most pregnant women need neither. If a pregnant patient has a DVT then it's heparin (LMWH) for the duration of the preganancy. If there is no DVT, and the patient has normal vitals (including O2 sat) then you could discharge and have the patient get serial US of the legs with instructions to return for new or worsening symptoms.

That leaves only the unstable pregnant patient who needs chest imaging, and those patients are quite rare.

As for d-dimer, some advocate adjusting up, based on trimester. I personally haven't seen enough convincing literature to adopt this practice myself, however.

1) However, V/Q has significantly lower (like 1/300th) the breast radiation of CT, so with normal lung anatomy it seems like the way to go--even with just the perfusion part

2) At the same time, you're still missing out on the pelvis being a source of clot

3) With dimers, there's a pretty good paper looking at normal preggos where the dimer goes up from 1st-3rd trimester by about 250 each one, but still definitely not a lot of good data on what to use as a cut off. Also, with the PERC rule, Jeff Kline advocates using 105 as the HR for pregnancy +/- dimer.

Overall, as Wilco mentioned, the unstable pt is so rare, given that PE alone is a 1/10,000 dz among pregnancy

 

[EctopicFetus]

Regarding the radiation. The problem with VQ is that a fair number are indeterminate so you ordered a test that did not give you an answer. In the few times this has come up CTA when needed but I think thats maybe once in my pretty brief career and I think one of the other guys in residency did the same with c/s from OB and Rads to discuss.

 

[Rendar5]

1) However, V/Q has significantly lower (like 1/300th) the breast radiation of CT, so with normal lung anatomy it seems like the way to go--even with just the perfusion part

It would seem to me that the fetus is going to take more damage from radiation than the mom, so I'd rather give the mom extra radiation into her chest than gie the fetus extra radiation in its blood stream.

 

[BJJVP]

I do a d-dimer and use the traditional cutoff. Never had a negative one but if I do, it will be reassuring to pt and family. I do US of legs knowing pelvic veins will be missed. If all is neg, I have a long discussion with pt and family regarding risk of radiation/contrast exposure. I do CTs if imaging is requested.

I agree with above poster in that I don't really like to pursue the dx unless pt is unstable.

I will probably sound crazy in this next paragraph but I find PE to be a relatively rare entity in comparison to how often we are taught to consider the dx. And contrary to popular teaching, I don't really consider it to be a do-not-ever-miss dx unless the pt is unstable. I know this is contrary to EM dogma (r/o life threats first). But I just think we scan way too many pregnant pts simply because there is no alternative dx for their CP, anxiety, dyspnea.

Admittedly, I have no real literature to back anything up definitively.

 

[SoCuteMD]

I D-dimer them, ultrasound their legs, and if D-dimer positive/ultrasound negative I discuss with OB and radiology. We use CT, not V/Q scan on our pregnant patients. I hate hate hate scanning pregnant women.

 

[deleted109597]

Some sources tell you to double your normal high d-dimer for gravid women. I agree with SoCute that if you d-dimer/US them and they're negative, you're done.

V/Q is still less radiation to the breasts, and with a foley, has neglible urine concentration at the level of the uterus.

Not a huge fan of CT PE in pregnant women.

 

[Rendar5]

i'm confused why there's so much more concern over the mom's breasts than the fetus' development. (it's an honest question, I mean does the effective radiation dose of breast tissue change to a significant degree because it's more active?? and is there less cross-over into the placenta than i thought of the radiation load of the perfusion scan?)

 

[Arcan57]

i'm confused why there's so much more concern over the mom's breasts than the fetus' development. (it's an honest question, I mean does the effective radiation dose of breast tissue change to a significant degree because it's more active?? and is there less cross-over into the placenta than i thought of the radiation load of the perfusion scan?)

The fetal dose of radiation for a traditional V/Q scan (not perfusion only) vs. a CTA is thought to be pretty similar. The CTA delivers a significantly higher dose of radiation to rapidly dividing breast tissue. I don't think anyone has studied whether being exposed to radiation while pregnant increases your breast CA risk more than if you aren't pregnant but most people assume it does.

 

[TrumpetDoc]

My first approach to pregnant patients presenting in a way that even makes me consider PE, APPY, etc. Is to curse relentlessly at the chart and/or screen and pound head into something preferably soft.

I am a fan of loading up on non invasive stuff. And talking with OB, the patient etc and scumenting the living hell out if the encounter.
If stable and NO vitals abnormal really don't like to do imaging.
But when I've had to I went with shielded CtA... After talking with their OB and PcP.