PAPERS OF THE MONTH - MAY 1996

This month features two papers from the May issue of the
JVS.  One is a clinical case-control report on the
inflammatory AAA from the Mayo Clinic, and the other is
an experimental study of endoluminal grafting of "man-
made" aneurysms in dog.  Stay tuned for next month, as
June features the largest and best vascular meeting of
the year (this year in Chicago).  I will be attending and
plan to report highlights related to AAA in the June
Papers of the Month.

1. Inflammatory abdominal aortic aneurysms: A case-
control study.  Nitecki SS, Hallett JW Jr, Stanson AW, et
al.  J Vasc Surg 1996; 23:860-9.  

Abstract, abridged from authors:

Purpose - to identify differences in characteristics and
outcome between patients with inflammatory (IAAA) and
noninflammatory AAA.

Methods - 29 patients with IAAA and a carefully case-
control matched group of 58 patients.

Results - Age, gender, and CV risk factors were similar. 
IAAAs were more likely to be symptomatic, have a positive
family history, and be current smokers.  The sed rate was
higher in IAAA by ~4x.  Op mortality was low in both
groups (6.8% vs zero, p ns), but IAAA patients had more
complications.  Five yr survivals were similar.  Perhaps
most interesting, follow up CAT scans revealed persistent
retroperitoneal inflammatory processes in 47% of IAAA's
(which involved the ureters in 32%).

Conclusion - "The study ... documents that persistent
retroperitoneal inflammation may be more prevalent than
... previously reported, and stresses the need for an
improved understanding of the pathogenesis and long-term
management of IAAAs."

Comment by mdt - Not much to add.  I see that the Mayo
group has an interesting abstract on the program for the
SVS/ISCVS meeting, reporting that the genetic
susceptibility factor for IAAA may be linked to the MHC
Class II DR-B1 locus.  We have been looking at that as
well, in the ordinary AAA (see Papers of the Month, March
96), so I will be writing a follow-up next month after I
hear their presentation.

2. Results of endoluminal grafting in an experimental
aortic aneurysm model.  Eton D, Warner D, Owens C, et al. 
J Vasc Surg 1996; 23:819-31.

Abridged abstract:

Surgical abdominal aortic dilations (AADs) of ~2x
diameter were created in 23 dogs by infrarenal iliac vein
patch angioplasties, preserving the lumbar and mesenteric
tributaries.  Several months later the AAD's were
excluded by transfemoral placement of thin-walled Dacron
grafts, anchored by balloon expandable stents.  Flow
arrest occurred immediately in the space between the
graft and the AAD, and no macroscopic flow could be
imaged 6-12 months later.  A reduction of ~10% occurred
in AAD diameter at 6 months, and thereafter the diameter
remained stable.  There were no anastamotic leaks.

Comment by mdt: These results are certainly encouraging
and first-rate work in animals is absolutely essential in
evaluating the long-term safety of endoluminal grafts. 
However, I should point out the splendid results do not
guarantee similar results in man, because of differences
in the way dog and man heal to Dacron.  I seem to
recollect that the dog aorta heals so well to Dacron that
long-term good results can be obtained even if the graft
is sewn in with chromic catgut.  Of course, this is not
true in man, and I've been around long enough to remember
several false aneurysms in patients whose grafts had been
sewn in with silk (which is biodegradable).  This is not
meant to be nit-picking with this excellent paper, but
just a reminder that the proof of the pudding must await
long-term studies in man.