1st Line investigation for a DVT and PE?

As the title says. This is confusing.

In my notes which I made for PBL in year 2 (using Oxford Handbook for reference) it says that for a DVT a D-Dimer would be the first line investigation (7th edition mind). It also says a CXR would be the best first line investigation for a PE.

Now in the Oxford Handbook of Clinical Surgery (2nd edition) it says that duplex scan is best for DVT as first line investigation and the CTPA for PE.

However when making notes tonight from "Lecture Notes on General Surgery" (11th edition) it seems to suggest a venography for DVT and CXR for first line investigations.

I'm quite certain that for PE a CTPA would be first-line as it's popped up in MCQs and always the right answer but I'm still confused as to what the definitive investigations are. Can anybody help me out with this or perhaps point me in the right direction e.g. official guidelines or something?

Thanks.

As the title says. This is confusing.

In my notes which I made for PBL in year 2 (using Oxford Handbook for reference) it says that for a DVT a D-Dimer would be the first line investigation (7th edition mind). It also says a CXR would be the best first line investigation for a PE.

Now in the Oxford Handbook of Clinical Surgery (2nd edition) it says that duplex scan is best for DVT as first line investigation and the CTPA for PE.

However when making notes tonight from "Lecture Notes on General Surgery" (11th edition) it seems to suggest a venography for DVT and CXR for first line investigations.

I'm quite certain that for PE a CTPA would be first-line as it's popped up in MCQs and always the right answer but I'm still confused as to what the definitive investigations are. Can anybody help me out with this or perhaps point me in the right direction e.g. official guidelines or something?

Thanks.

It Depends upon the assessed risk of having a DVT

http://eng.mapofmedicine.com/evidence/map/venous_thromboembolism_vte_diagnosis_and_management1.html

That is basically what we did for DVTs when I was on AMU. We calculated the wells score and then depending on whether they were clinically high or low risk did either a d-dimer or a doppler.

For PE again it was a clinical assessment with a different wells score and if it was considered likely we did a CTPA, however they would have normally had a chest x-ray, bloods and ecg before that to look into other potential causes of breathlessness. If the patient was a pregnant woman our protocol said to do bilateral leg doppler though I didn't ever have to do that)

You won't get a CTPA in most hospitals without having done a CXR first. This is not because CXR is an investigation for PE ( although rarely you can see signs) but because you should rule out other causes of SOB prior to CTPA