Emery, C.

Goldberg, R.J.

Lessard, D.

Spencer, F.A.

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JOURNAL OF VASCULAR SURGERY
January 2008240 Abstractsreduced for patients with acute myocardial infarctions (odds ratio [OR],
0.48; 95% confidence interval [CI], 0.33-0.71). For the medical conditions
studied taken together, mortality in the hospitals with resident-to-bed ratio
of 1 compared with those with resident-to-bed ratio of 0 was also less (OR,
0.74; 95% CI, 0.61-0.89). Similarly, mortality was improved in the three
other medical conditions excluding acute myocardial infarction (OR, 0.79;
95% CI, 0.63-0.98). Compared with hospitals in the 25th percentile of
teaching intensity, hospitals in the 75th percentile of teaching intensity had
an 11.1% relative mortality decrease, and those in the 90th percentile of
teaching intensity had a 15.9% relative decrease in mortality for all the
combined medical conditions.
Comment: This study raises a number of interesting questions about
the impact of duty hour reform on in-hospital mortality. There are many
possible explanations for the findings, including more attending involve-
ment and more use of mid-level providers in response to the resident work
hour restrictions. In addition, the failure of mortality rates to decrease in the
surgical patients does not necessarily imply poor care of the surgical patients.
Perhaps these patients were already getting excellent care, and this care was
not affected by a decrease in work hours by the surgical residents. Neverthe-
less, surgical program directors must ask themselves whether they are doing
well or whether they could be doing better, or perhaps both.
Idraparinux Versus Standard Therapy for Venous Thromboembolic
Disease
The van Gogh Investigators. N Eng J Med 2007;357:1094-104
Conclusion:Once-weekly subcutaneous idraparinux for 3 to 6months
has efficacy similar to heparin plus a vitamin K antagonist for treatment of
deep venous thrombosis (DVT). Idraparinux is inferior compared with
standard therapy for treatment of patients with pulmonary embolism (PE).
Summary: Idraparinux is a long-acting synthetic inhibitor of factor X
activity. Preliminary studies suggest that for treatment of venous thrombo-
embolism (VTE), a fixed subcutaneous dose of idraparinux given once
weekly is as effective and results in less bleeding than vitamin K antagonist (J
Thrombosis Homeostasis 2004;2:47-53). In this study, the authors investi-
gated the potential use of idraparinux as a substitute for standard therapy for
VTE.
This is a report of two randomized, noninferiority, open-labeled trials
comprising 2904 patients with DVT and 2215 patients with PE. Patients
received either heparin, followed by adjusted doses of a vitamin K antagonist
for 3 or 6 months, or subcutaneous idraparinux (2.5 mg once weekly) for 3
or 6 months. The primary end point was the 3-month incidence of symp-
tomatic recurrent VTE. In the DVT study, the incidence of recurrent VTE
at day 92 was 2.9% in the idraparinux group and 3.0% in the standard therapy
group (odds ratio [OR], 0.98; 95% confidence interval [CI], 0.63-1.50).
This result satisfied a prespecified noninferiority requirement. The rate of
clinically important bleeding was 4.5% in the idraparinux group and 7.0% in
the standard-therapy group (P  .004). At 6 months, the hazard ratio for
recurrent VTE with idraparinux was 1.01. At 6 months, the bleeding rates
were similar in the standard-therapy and idraparinux groups. In patients with
PE, recurrence at day 92 was 3.4% in the idraparinux group and 1.6% in the
standard therapy group (OR, 2.14; 95%CI, 1.21-3.78). This finding did not
meet the prespecified noninferiority requirement.
Comment: The results suggest idraparinux is equally efficacious in the
treatment of DVT as heparin followed by warfarin therapy. It appears to be
inferior to heparin followed by warfarin therapy for treatment of PE. If
additional studies support differences in clinical efficacy in treatment of DVT
vs PE, a long-held concept that the same anticoagulant therapies can be used
forDVT and PEwill need to be re-addressed. Idraparinux is a promising new
anticoagulant for treatment of DVT. The enthusiasm for this very long-
acting agent, however, will likely be limited by lack of a specific antidote that
can be administered during bleeding episodes.
Extended Prophylaxis of Venous ThromboembolismWith Idraparinux
The van Gogh Investigators. N Engl J Med 2007;357:1105-12.
Conclusion: During a 6-month period of extended prophylaxis after
treatment of venous thromboembolism (VTE), idraparinux effectively pre-
vents recurrent VTE but has an increased risk of major hemorrhage.
Summary: This is one of two articles evaluating idraparinux in treat-
ment of venous thromboembolism. (See also “Idraparinux Versus Standard
Therapy for Venous Thromboembolic Disease” in this abstract section.)
Because this novel factor Xa inhibitor has a long half-life and does not
require laboratory monitoring, its use as an extended method of prophylaxis
in patients requiring long-term prophylaxis against VTE seems attractive.
This is especially so in that it appears to be as effective as heparin after
warfarin therapy for treatment of deep venous thrombosis. In this study, the
authors evaluated the efficacy and safety of a 6-month extension of prophy-
laxis against recurrent VTE using idraparinux in patients who had already
received 6 months of prophylaxis with either idraparinux or a vitamin K
antagonist. Patients were entered into the study if it was determined that
anticoagulation beyond 6 months after an initial episode of VTE waswarranted. Patients were randomized to receive once-weekly injections of
2.5 mg of idraparinux or a placebo for 6 months, without monitoring. The
primary efficacy end point was recurrent VTE, and the primary safety end
point was major bleeding.
The study enrolled 1215 patients, 594 in the idraparinux group and
621 in the placebo group. The rate of recurrent VTE was 1.0% (6 of 594) in
the idraparinux group and 3.7% (23 of 621) in the placebo group (P 
.002). Patients in the idraparinux group had 11 major bleeding episodes,
and the placebo group had none (P  .001). Three of the 11 bleeding
episodes were fatal intracranial hemorrhages. Patients whose initial treat-
ment after VTEwas 6 months of a vitamin K antagonist were compared with
patients whose initial treatment after VTE was 6 months of idraparinux.
When subsequently treated with placebo, patients initially treated with 6
months of idraparinux had a lower overall incidence of recurrent VTE (0.7%
vs 5.9%). Patients who received 6 additional months of idraparinux had a
higher incidence of major bleeding (3.1% vs 0.9%).
Comment: The two abstracts on idraparinux in this month’s issue of
the Journal of Vascular Surgery indicate idraparinux is an effective anticoag-
ulant for treatment of DVT and for extended prophylaxis of VTE. This
article in particular, however, highlights a significant drawback of this drug,
which is the lack of an effective antidote to administer during hemorrhagic
episodes.
Prediction of Cerebral Hyperperfusion after Carotid Endarterectomy
Using Cerebral Blood Volume Measured by Perfusion-Weighted MR
Imaging Compared with Single-Photon Emission CT
Fukuda T, Ogasawara K, Kobayashi M, et al. Am J Neuroradiology 2007;
28:737-42.
Conclusion: In patients without contralateral internal carotid artery
(ICA) occlusive disease, cerebral blood flow volume (CBV), as measured by
perfusion-weighted magnetic resonance imaging (PWI), may identify pa-
tients at risk for cerebral hyperperfusion after carotid endarterectomy
(CEA).
Summary: Cerebral hyperperfusion after CEA may result in intracra-
nial hemorrhage and perhaps even impairment of cognitive function without
associated intracranial hemorrhage (J Neurosurg 2005;102:38-44). Mag-
netic resonance imaging can characterize cerebral hyperperfusion using
timed boluses of contrast agents and can provide quantitative hemodynamic
values, such as CBV (Stroke 2006;37:388-92). In this study, the authors
measured CBV using PWI in patients undergoing CEA for unilateral70%
ICA stenosis. Patients in this study did not have significant contralateral ICA
occlusive disease. Fifty-four of the 70 patients had coexisting hypertension.
With respect to their ICA stenosis, 46 were symptomatic and 24 were
asymptomatic. Cerebral blood flow was measured using single-photon
emission computed tomography (SPECT) before and immediately after
CEA and on the third postoperative day.
There was a significant correlation between preoperative CBV as mea-
sured by PWI and increases in cerebral blood flow immediately after CEA (R
 0.785, P  .0001). Using a definition of hyperperfusion as a 100%
increase in cerebral blood flow compared with preoperative values, hyper-
perfusion was observed in 7 of 15 patients (47%) with elevated preoperative
CBV values. No patients with normal preoperative CBV values exhibited
hyperperfusion after CEA. Elevated preoperative CBV was the only signifi-
cant independent predictor of post-CEA hyperperfusion. A clinical hyper-
perfusion syndrome developed in two of the seven patients who displayed
hyperperfusion immediately after CEA.
Comment: SPECT using an acetazolamide challenge can identify
patients at risk for cerebral hyperperfusion after CEA (Stroke 2001; 32:
1567-73). Limited availability and high cost limits routine clinic use of
SPECT. Perfusion weighted imaging, however, requires short scanning
times and can be incorporated into clinical MRI examinations. This study
suggests that patients at risk for cerebral hyperperfusion after intervention
for high-grade ICA stenosis may potentially be identified using currently
widely available technology.
Upper Extremity Deep Vein Thrombosis: A Community-Based
Perspective
Spencer FA, Emery C, Lessard D, Goldberg RJ, and the Worcester Venous
Thromboembolism Study Investigators. Am J Med 2007;120:678-84.
Conclusion: Upper extremity venous thrombosis (UEDVT) has dif-
ferent risk factors, incidents of pulmonary embolism (PE), and differences of
timing and location of recurrent venous thromboembolism (VTE) com-
pared with patients with lower extremity deep venous thrombosis (DVT).
Summary: The authors sought to compare risk factors, magnitude of
venous thrombus, and management strategies in persons with UEDVT vs
lower extremity DVT diagnosed in 1999. This population-based investiga-
tion involved review of medical records from Worcester, Massachusetts
(population 478,000) that had had International Classification of Disease
(9th revision) codes consistent with possible DVT during 1999. The age
adjusted rate of UEDVT was 16 per 100,000 population (95% confidence
JOURNAL OF VASCULAR SURGERY
Volume 47, Number 1 Abstracts 241interval [CI], 13-20) compared with 91 per 100,000 population for lower
extremity DVT (95% CI, 83-100). Compared with patients with lower
extremity DVT, patients with UEDVT were more likely to have undergone
recent central venous access, a cardiac procedure, or to have been in an
intensive care unit. Short-term and 1-year recurrence rates of VTE and
all-cause mortality were not different in patients with upper vs lower extrem-
ity DVT. Patients with UEDVT, however, were less likely to have PE at
presentation or at follow-up compared with patients with lower extremity
DVT. None of the patients presenting with UEDVT were diagnosed with
simultaneous PE, whereas PE was recognized clinically in 15% of patients
presenting with lower extremity DVT. At 30 days, only one patient with
UEDVT was diagnosed with PE, and no other clinically recognizable PE
occurred during a 1-year follow-up in the patients with UEDVT. Five
patients with lower extremity DVT had a newly diagnosed PEwithin the first
month, and clinically recognizable PE developed in seven patients by 1 year.Intravenous heparin was used to treat 47.8% of patients with UEDVT vs
61.8% of those with lower extremity DVT (P  .03). Subcutaneous low-
molecular-weight heparin was used in 69.6% of patients with UEDVT vs
70.5% of patients with lower extremity DVT (P  .87). At hospital dis-
charge, warfarin therapy was more frequent in patients with lower extremity
DVT than in those patients with UEDVT (73.7% vs 56.5%, P  .004).
Comment: The American College of Chest Physicians suggests
UEDVT should be treated similarly to lower extremity DVT (Chest 2004;
126:401S-428S). The observations presented here suggest that despite a
lower use of long-term anticoagulation, UEDVT may have a more benign
prognosis than lower extremity DVT in terms of PE. Prospective random-
ized studies are clearly needed to optimize potential prophylactic treatment
for patients at risk for UEDVT and therapeutic treatment for those who
develop the disease.


Upper Extremity Deep Vein Thrombosis: A Community-Based Perspective 

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Upper Extremity Deep Vein Thrombosis: A Community-Based Perspective

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