Tuesday, June 06, 2006

Phlebotomy and secondary polycythemia vera

Is there ever an indication for phlebotomies for secondary PCV? I was always under the impression that the treatment is supplemental oxygen. Is there any data to support this practice?

9 comments - CLICK HERE to read & add your own!:

Baleeiro said...

I haven't seen any data either. The treatment should be to correct the hypoxemia. Otherwise we should be starting more COPD Pts on Hydrea...

Jennings said...

Well, I'm having a really hard time convincing the hematologists of that....

Baleeiro said...

I haven't found much data but came across the abstract for this paper by Schwarcz on J Vasc Surg. 1993 Mar;17(3):518-22; discussion 522-3.
They were comparing the risks of hypercoagulability/increased viscosity in tru P. vera vs COPD-associated erythrocytosis and these were their findings:
"Overall, patients with polycythemia vera had a greater number of thromboembolic events per patient (p < 0.05) and more peripheral arterial thromboemboli (p < 0.005) than did patients with polycythemia as a result of smoking (Fisher's Exact Test). CONCLUSIONS: Thus the results of this study demonstrate that smokers' polycythemia does not represent a hypercoagulable state equivalent to that of polycythemia vera."

Jennings said...

Well, interestingly this guy had acute DVT's in 2003 and got an IVC filter. However, his Hct on that admission was in the high 30's low 40's.

Baleeiro said...

I have also found this abstract from Chest: Chest. 1990 Nov;98(5):1073-7 (couldn't open the full text online). They did phlebotomies and found improved exercise tolerance in a group of Pts. However this was not controlled and we don't know if the benefit wouldn't have been the same with O2 and bronchodilators...
Also, low H/H (as a marker of chronic Dz/inflammation) is a negative prognostic indicator in COPD.

Krayem said...

well, the half life of RBC is 3-4 months. If you start a hypoxic patient on oxygen today, theoretically it may be at least 4 months before he is where he should be. I would do a phlebotomy if he has signs/symptoms suggestive of hyperviscosity, and his hemoglobin is above 18...

Jennings said...

Krayem, regarding the phlebotomy for Hgb > 18 in secondary PCV: where did you get that number as a decision to phlebotomize? Is there (published) data for that?

Baleeiro said...

Moreover, I do understand the issue of the half-life of RBCs but the bigger question to me is: most patients with COPD have had COPD for years before they are diagnosed. Is 2-3 months of "faster resolution" of their erythrocytosis going to have such a big impact? For a chronic Dz as COPD it would be like saying: you better start pulm. rehab today, next week might be too late.

Krayem said...

well, the phlebotomy is only to help resolve the "hyperviscosity" symptoms if the patient has such symptoms...otherwise, no need to do it.....it is a safe procedure, that may have significant benefit for a symptomatic patient...
as far as the "hemoglobin 18", "I" came up with this number..no published data, at least that I am aware of, to back it up...what I remember from my readings about PCV, oyu suspect it when Hemoglobin is > 17.5 in men and 16.5 in women...also there is this article on emedicine http://www.emedicine.com/med/topic1863.htm
which quotes studies suggesting that there may be a benefit of phlebotmy for secondary polycythemia with a Hct of 60 (which is close to Hemoglobin of 20)...I decided that 18 is the number I feel comfortable with, with the presence of symptoms...