The Aneurysm Information Project

Apr 1997 Papers of the Month

1. Biddinger A, Rocklin M, Coselli J, Milewicz DM.  Familial aortic
dilations and dissections: A case control study.  J Vasc Surg 1997;
25: 506-11).

Abstract (adapted from authors):

Families were ascertained through 158 nonsyndromic probands
referred for repair of thoracic aneurysms or dissections and their
843 first-degree relatives.  A control group of 547 first-degree
relatives was derived from 114 proband spouses.  Relatives of
probands demonstrated a higher prevalence of thoracic aortic
aneurysms and sudden death when compared with the control group. 
Relative risks were 1.8 in fathers,  10.9 in brothers, and 1.8 in
sisters.

Comment by mdt: Finally, a sound study that shows what many of us
have suspected all along!  It was interesting to me that relatives
of the probands did not have an excess of abdominal aortic
aneurysms (AAA).  Thus, while both diseases have genetic
susceptibility factors, genetic heterogeneity must reflect the
clinical heterogeneity of the diseases.


2. Katz DJ, Stanley JC, Zelenock GB.  Gender differences in AAA
prevalence, treatment, and outcome.  J Vasc Surg 1997; 25: 561.

Abstract (adapted from authors):

Men were 1.8 times as likely as women to have an intact AAA treated
surgically, and 1.4 times as likely to have a ruptured AAA treated
surgically.  Women who had operations for intact AAA had a 1.4
times greater risk of dying compared with men, and a 1.4 times
greater risk of dying after repair of a rupture.  " Whether these
findings are a result of clinical practice patterns or biologic
factors remain to be determined, but gender differences of the
magnitude observed in the present study are sufficient to justify
a prospective investigation involving a regional or national cohort
of patients."

Comment by mdt: I agree.  One possible explanation is that the
women were significantly older than the men for all comparisons. 
For example, the average age at admission for women was 73 (intact)
and 77 (ruptured).  For men it was 69 (intact) and 72 (ruptured).
Thus, a somewhat higher mortality rate for women would not be
unexpected (overall: 12% versus 7%).  Similar considerations apply
to referral for surgery.  Because they may be more likely to be
significantly older than men when the AAA is discovered, a fewer
proportion might be fit for elective surgery.  I can't really
imagine that there is any prejudice against women in referral for
surgery.

3. Juvonen J et al.  Demonstration of Chlamydia pneumoniae in the
walls of AAA.  J Vasc Surg 1997; 25: 499.

Abstract (adapted from authors):

The authors find a surprisingly high percentage of aneurysmal
aortas in which Chlamydia could be detected by a variety of
techniques, including immunohistochemistry, PCR, and electron
microscopy.  They observe that the organism has been previously
demonstrated in atherosclerotic lesions of the aorta and the
coronary arteries.  They speculate that it may have an etiologic
role in AAA.

Comment by mdt:  The fatal flaw in this paper is the lack of a
truly comparable control group.  The controls were autopsy
specimens, and "specimens with histologic evidence of
atherosclerosis were eliminated from this series."  Since AAA's
(just like aneurysms associated with cervical ribs and
coarctations) become atherosclerotic; it would have been much more
appropriate to use controls with atherosclerotic lesions.  The
Chlamydia may be a feature of the atherosclerotic lesion and not
the aneurysmal dilatation itself.