Cadman, A.

Fitzsimmons, L.

Lawrence, J.A.L.

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To clot or not to clot? That is the question with central venous catheters 

ABSTRACTS
Gregory L. Moneta, MD, Abstracts Section EditorTo clot or not to clot? That is the question with central venous catheters
Cadman A, Lawrence JAL, Fitzsimmons L, et al. Clin Radiol 2004;59:349-
55.
Conclusion: Placement of the tip of a tunneled central venous catheter
(CVC) in either the distal third of the superior vena cava (SVC) or the
proximal right atrium is superior to more proximal placement of the catheter
tip in prevention of catheter-related central venous thrombosis.
Summary:This was a retrospective review of 428CVCs inserted in 334
patients. The patients were randomly selected for review, and chest x-ray
films were obtained after catheter insertion. Follow-up x-ray films and
Doppler ultrasound scans were reviewed for venous thrombosis. Total
follow-up was 23,040 days (median, 72 days; range, 1-720 days). Venous
thrombosis occurred in 5 of 191 CVCs (2.6%) with distal positioning of the
catheter tip (distal third of SVC or right atrium), 5 of 95 CVCs (5.3%) with
an intermediate catheter tip position (middle third of SVC), and 20 of 48
CVCs (41.7%) with a proximal catheter tip position (proximal third of SVC
or thoracic inlet veins). CVCs with tips in a proximal position were 16 times
more likely to be associated with venous thrombosis than were those with
tips in a distal position (P  .0005). No catheter (n  58) with the tip
located in the right atrium became thrombosed or caused complications.
There was a 7.8% displacement rate in women, compared with 3.6% in men.
Venous thrombosis was more than twice as likely to develop in women in
whomCVCs were inserted, compared withmen. CVCs inserted through the
left subclavian vein were almost 4 times more likely to develop venous
thrombosis than those inserted through the right subclavian vein.
Comment: The recommendation for more distal position of CVC tips
to prevent catheter-associated venous thrombosis is not new, but deserves
emphasis. This study has a number of potential limitations in that no
follow-up was recorded in 1 of 3 patients, patient follow-up notes were not
reviewed, and clinically suspected venous thrombosis not imaged were not
included. Nevertheless, the authors’ recommendation for more distal posi-
tioning of venous catheter tips to avoid CVC-associated thrombosis likely
remains valid.
Long-term prognostic value of asymptomatic cardiac troponin T ele-
vations in patients after major vascular surgery
Kertai MD, Moersma E, Klein J, et al. Eur J Vasc Endovasc Surg 2004;28:
59-66.
Conclusion: An elevated perioperative cardiac troponin T (cTn-T)
concentration after major vascular surgery is associated with increased all-
cause mortality.
Summary: cTnT is both specific and sensitive for myocardial injury.
Elevations in cTn-T concentration without persistent or new electrocardio-
graphic (ECG) abnormalities and no clinical evidence of ischemia are
common after major vascular surgery. The authors sought to examine the
long-term prognostic value of elevated cTn-T levels in patients after major
vascular surgery. Between 1996 and 2000, 393 patients who underwent
successful aortic or infrainguinal vascular surgery and in whom cTn-T was
routinely sampled were followed up until May 2003 (median, 4 years) for
all-cause mortality. During this period total creatinine kinase; creatine
kinase, myocardial bound; and cTn-T were routinely screened in all patients
on postoperative days 2, 3, and 7. Patients with suspected myocardial
ischemia were also evaluated with ECG. Elevated cTn-T level was defined as
serum concentration 0.1ng/mL in any sample.
Eighty patients (20%) died during follow-up. The all-cause mortality
rate was significantly higher in patients with elevated cTn-T levels compared
with patients with normal cTn-T levels (41% vs 17%; P  .001). This
association between elevated cTn-T level and increased all-cause mortality
(hazard ratio, 1.9; 95% confidence interval, 1.1-3.1) was independent of
baseline clinical characteristics. Elevated cTn-T levels had significant prog-
nostic value in patients with and without renal dysfunction, in patients with
transient ECG abnormalities, and in those with abnormal levels of creatine
kinase, myocardial bound.
Comment: It is difficult to know how to apply these data clinically. The
adverse prognosis imparted by elevated cTn-T levels does not become
known until after the patient has undergone the surgical procedure. The
findings are interesting, but do not argue for routine screening for elevated
troponin levels in patients without symptoms.
Focused high-risk population screening for carotid arterial stenosis
after radiation therapy for head and neck cancer
Steele SR, Martin MJ, Mullenix PS, et al. Am J Surg 2004;187:594-8.
1060Conclusion: Prevalence of carotid arterial disease in patients with
previous cervical radiation therapy is sufficiently high that screening for
carotid artery stenosis should be routine.
Summary: The authors used a prospectively maintained data base to
identify patients who had received cervical high-dose radiotherapy (mini-
mum, 5500 cGy). Patients were then screened with bilateral carotid duplex
ultrasonund screening. Duplex findings were divided into those with normal
or mild carotid artery stenosis (50%) and significant carotid artery stenosis
(50%). Relationships between standard demographic risk factors and
screening outcomes were also analyzed.
Forty patients with a history of cervical radiation were screened in this
study (mean age, 68.2 years; range, 26-87 years).Mean cumulative radiation
dose was 6420 cGy (range, 5500-7680 cGy). There was a mean duration of
10.2 years since the last radiation treatment. Duplex ultrasound scans
revealed that 40% of patients had significant carotid artery stenosis. Patients
with and without significant stenosis were comparable in terms of radiation
dose, tobacco use, age, comorbid conditions, and post-radiation intervals
(P  NS). Six patients had unilateral carotid occlusion, and 6 patients had
greater than 50% bilateral carotid stenosis. Eight patients (7.5%) had sus-
tained a stroke after radiation therapy.
Comment: The authors argue that the prevalence of carotid artery
disease after radiation therapy warrants aggressive screening as part of
post-radiation care. However, only 3 patients (7.5%) sustained a stroke after
radiation therapy. Given the potential increased risk for carotid intervention
in patients with previous radiation therapy, and perhaps decreased durability
of carotid interventions in patients with radiation therapy, it may be that the
authors’ data suggest that screening for asymptomatic carotid artery stenosis
is not indicated after radiation therapy.
Endoleak after endovascular abdominal aortic aneurysm repair: Impli-
cations for duration of screening
Corriere NA, Feurer ID, Becker SY, et al. Ann Surg 2004;339:800-7.
Conclusion: After endovascular abdominal aortic aneurysm repair
(EVAR) there is a decreasing risk for detection of endoleak as the number of
normal postoperative computed tomography scans increases. Endoleak,
however, can be identified as late as 7 years after EVAR, and therefore a
reduction in screening frequency for endoleak cannot be recommended at
this time.
Summary: There are no current criteria for reducing the frequency of
screening imaging studies to detect endoleak after EVAR. The authors
collected imaging and follow-up data for 220 patients who underwent
EVAR to assess for late endoleak and the risk for development of endoleak
over time. Data included preoperative aneurysm diameter, postoperative
increase in aneurysm diameter, and number of normal surveillance studies
after EVAR.
Endoleak was detected during follow-up in 24% of 200 patients after
EVAR. Endoleak was detected on average at19 months (range, 0.4-101
months). At 1, 6, 12, and 24 months endoleak-free survival was 90%, 80%,
77%, and 73%, respectively. An increasing number of normal screening
studies was negatively associated with risk for subsequent endoleak develop-
ment (P .001). An increase in aneurysm diameter was positively associated
with risk for endoleak (P  .04).
Comment: A major limitation to EVAR is the need for continuous
follow-up with imaging studies. This study demonstrates a decreased risk for
new endoleak development as the number of normal screening studies
increases. However, new endoleaks were discovered as late as 85 months
after EVAR. At this time cessation of surveillance for endoleak cannot be
recommended.
The metabolic syndrome is associated with advanced vascular damage
in patients with coronary heart disease, stroke, peripheral arterial
disease or abdominal aortic aneurysm
Olijhoek JK, Van Der Graff Y, Banga J-D and SMART Study Group. Eur
Heart J 2004;25:342-8.
Conclusion: In patients with peripheral vascular or coronary disease
the presence of metabolic syndrome is associated with increased vascular
damage.
Summary:Metabolic syndrome consists of 3 or more of the following:
abdominal obesity (waist circumference 102 cm in men or 88 cm in
women), hypertension (systolic blood pressure 130 mm Hg diastolic
blood pressure 85 mm Hg), hypertriglyceridemia (serum triglyceride
concentration 150 mg/dL), low high-density lipoprotein cholesterol


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To clot or not to clot? That is the question with central venous catheters

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