Dear Dr Marco Cei,

I think your questions are very interesting and important questions. It seems logical that we should monitor our patients before stopping anticoagulation treatment. We do this for many other conditions than VTE. Especielly this is important in the group with idiopathic pulmonary embolism or deep venous thrombosis (VTE= venous thromboembolism). Idiopathic cases have higher risk for recurrency. 1) I do not think performing CT angio rutinely is an option due to the contrast and radiation. If any direct visualization of the lung should be used lung scintigraphy would be prefered but this remains to be determined. Instead I think a echocardiogram is sometimes good way to monitor the patient in the acute treatment. Still it is unclear if and which patient thrombolysis should be performed in. Hopefully the The Pulmonary EmbolIsm THrOmbolysis (PEITHO) trial my answer this question according to Goldhaber. As the major mortality in pulmonary embolism patients is in the group with pulmonary hypertension and right ventricular dysfunction (RVD) echocardiogram is a good prognostic test in the acute treatment of PE. As suggested by Goldhabet normal Troponin T or I levels and NT-proBNP/BNP levels is a good screening test for RVD. Those with increased values should be screened with echocardiogram. If important RVD one could think of thrombolysis or not as we do not know which is best when patient has normal blood pressure. If in circulatory chock thrombolysis is definitely an option though the evidence are sparse (one study stopped after inclusion of 8 patients-4 with heparin treatment died and for with thrombolysis survived). I think patients with initial pulmonary hypertension should be screened with echocardiogram befor stopping antiocoagulantia treatment after 6 months though this is not evidenced based medicine. Otherwise there is no indication for echocardigram before stopping treatment. There is a recent study trying to answer some of your questions by Poli D et al in Thromb Haemost. 2013 Jan 31;109(2):181-6. doi: 10.1160/TH12-07-0534. Epub 2012 Nov 29. (Risk of recurrence in patients with pulmonary embolism: Predictive role of D-dimer and of residual perfusion defects on lung scintigraphy)

This study suggest that d-dimer my be potentially useful though lung scintigraphy was not. However, this need to be repeated in larger studies. However, I think the new SPECT method is much better than the old lung scintography and should be evaluated instead regarding the possibility of predicting recurrency (for reference regarding SPECT see this article J Nucl Med. 2001 Aug;42(8):1288-94. Comprehensive ventilation/perfusion SPECT. Palmer J, Bitzén U, Jonson B, Bajc M.).Moreover, I think a laboratory test performed during treatment would be clinicaly useful than a test after stopping treatment.D-dimer is in most studied tested after quiting treatment.

In conclusion. At the moment I think there is to little evidence to rutinely use echocardiogram, d-dimer, residual thomboses and SPECT for determining the length of anticoagulation. However, it could be helpful in selected cases.Regarding how long to treat patients after a first VTE this is a balance between risk for VTE and bleeding. The following review by de jong et al is a recent overwiev of guidelines. )Br J Haematol. 2012 Aug;158(4):433-41. doi: 10.1111/j.1365-2141.2012.09196.x. Epub 2012 Jun 26. Duration of anticoagulant therapy for venous thromboembolism: balancing benefits and harms on the long term. de Jong PG, Coppens M, Middeldorp S).

with best regards Bengt Zöller

Thank you Bengt for your exhaustive answer. I agree with you that the benefit of routine CT pulmonary angiography should be weighted against the risks of contrast medium and radiation. I'm not aware of studies evaluating D-dimer level during treatment, however I usually took it into account when evaluating the decision to stop therapy. Of course, the evidence isn't in, and this is indeed what I wish to know.

The available evidence on the course of PE is still scarce and no firm recommendations could be made, to date. Based on the results of a number of study and GCPs it seems reasonable to perform a single echocardiographic examination after 6 months and regular clinical surveillance every 6 months for at least 2 years. The prescription of lung scan or chest CT for FUP purposes does not seem to be cost-effective and should be considered only if a clinical suspicion of CTEPH or recurrent PE arises ( see also ESC algorithm for CTEPH). The optimal duration of anticoagulant treatment is still unknown but in severe PE an extended treatment for months or years should be considered, provided the the haemorragic risk is low. It could be a matter of interest considering that the onset of the majority of CTEPHs seem to be confined in the first two years ( however in the european registry of CTEPH a number of diagnoses were made after several years) ando could be a good point for estimation of the duration of anticoagulant treatment after a first episode of at least proximal segmental PE.

Dear Raffaele, thank you. Indeed, I prefer to follow my patients with echocardiogram. However, I still see many doctors, especially those who are lung specialists, that rely on lung scintigraphy to guide the therapy. It seems to me that this practice pose an unnecessary risk of radiation exposure to the patients.

Dear Marco, I fully agree. There is no evidence, to my knowledge, that lung scan or CT should guide the duration of anticoagulant treatment, which should be based on the individual basal and perhaps postbasal ( currently only D-dimer but with some concern) prothrombotic risk profile and balanced against the individual hemorragic risk profile. The predictive value of residual pulmonary thromboembolic material which is common after PE ( from 30 to 50%) is still unknown and one should also compare it with the low incidence of subsequent CTEPH ( from 0,5% to 3,8% in 2 years).

In the study we are running in Sarajevo, we were able to follow up PE patients after 3 month, and if normalized perfusion was observed and no other risk factors were present, the anticoagulant therapy was terminated. new control after 6 months did no show reccurencein any of them . This way is also possible to identify patients that will need livs long therapy

Dear Marika, thank you for your contribution. However, as Raffaele has already pointed out, residual pulmonary thromboemboli are common after PE and their clinical significance remain to be clarified. Dr. Eugenio Picano, MD, has estimated that a lung scintigraphy is equivalent to 50 chest X-rays in terms of radiation exposure (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC381057/table/tbl1/). Since you are well experienced in V/PSPECT, would you be so kind to tell us how much is the dose exposure of this examination, in terms of mSv?

For the V/P SPECT procedure it is about 2-2.2 mSV, when standarized method is used according european guidelines

The significansce or residual perfusion defects is possible to validate again by follow up clinicaly and by scintigraphy. It is about the extension of résidual defects, and possibly reccurence

A therapeutic strategy based on imaging is intriguing, provided that it has been formally validated. However, a couple of issues should be considered: the studies which tailored the duration of anticoagulant drugs based on the presence or absence of residual venous thrombus fail to avoid VTE recurrences in a low but not so neglibile fraction of patient fully recanalized. One more interesting issue is that related to the normalization of perfusion in a segmental pulmonary vessel after lung scan when the original intraluminal defect is partially reduced in size: is it a real phenomenon? should we consider it as a false negative recanalization of PE?

Hi, I'm a postdoc at the university of Southampton and have found this discussion very interesting as I've just been diagnosed with a  pe at the age of 25. I've come across this discussion as I've just had a letter for an echocardiogram next week and wondered whether this was routine or there was something about my results from diagnosis that they want to look at? Any help would be much appreciated. 

Dear Emma, thank you for your interest. How old are you now? As Raffaele has already stated, an echocardiogram is probably most useful after 6 months from the index event, and probably no more indicated after 1 or 2 years from PE if you are fully asymptomatic. Moreover, are you still on treatment?

Hi, I'm still 25 I was only diagnosed last month! And yes I'm on warfarin now currently 3-4 mg. thanks for the help

Hi, I'm quite sure that they ordered an echocardiogram as a routine procedure to screen for post-embolic pulmonary hypertension or to have a baseline exam if in the near future you will become symptomatic for dyspnea (I hope no, of course!). Because ultrasound is safe, I fully agree with this follow-up program, especially in a young woman like you.  

what is recommended is Ventilation/perfusion SPECT as a examination , acute and follow up. Than you can exactly obtain regression of perfusion defects and quantify it as well

Hi! I'm Internist, I find this is an interesting discussion. I had a case, suspected case of PE post delivery (LSCS), her CTPA- no thromboembolism noted. However, she improved well with anticoagulant therapy, but due to COVID 19 she continued warfarin around 10 months as she couldn't come for follow up at 6 months.

1. which investigations would be better for her ... CTPA, Echo, lung scintigraphy (is not available in our set up) before warfarin discontinuation?@.

2. Role of aspirin after 6 months??

I found out CTVS Doctor planned for CTPA and prescribed low dose aspirin.

Would be please answer my queries? thank you