Diagnostic ultrasound ( PDFDrive )

994 PART III Small Parts, Carotid Artery, and Peripheral Vessel Sonography
FIG. 27.45 Nonocclusive Thrombus in Brachial Vein. Transverse
noncompressed image of nonocclusive thrombus (*) in one brachial
vein in the paired brachial veins. A, Brachial artery. See also Video 27.22.
FIG. 27.43 Acute Internal Jugular Thrombus. Transverse image
of a noncompressible internal jugular vein illed with thrombus (*).
Arrowhead shows carotid artery. See also Video 27.21.
FIG. 27.44 Nonocclusive Chronic Internal Jugular Thrombus. Longitudinal
color Doppler image of the small-caliber proximal internal jugular
vein with irregular thrombus adjacent to wall, with thickened valves
(arrows).
be absence of phasicity without stenosis in the central veins if
a hemodialysis grat or AVF is present in the upper arm.
Unlike the lower extremity, most cases of upper extremity
DVT are related to the presence of a central venous catheter or
electrode leads from an implanted cardiac device. Approximately
35% to 75% of patients who have upper extremity venous catheters
develop thrombosis, and approximately 75% are asymptomatic 104-106
(Fig. 27.46, Video 27.23 and Video 27.24).
Frequently a ibrin sheath is found adjacent to the catheter
and may be seen ater catheter removal. It is important to look
carefully at the valves for adherent thrombus. Whether the catheter
access site is the subclavian vein or the IJV afects the complication
rate. Trerotola and colleagues 107 examined only patients who
had symptomatic upper extremity DVT and found a greater
incidence of DVT in patients who had subclavian venous access
than in those who had internal jugular access. he placement
of large-bore catheters into the subclavian vein should be avoided,
especially in patients who have end-stage renal disease (ESRD)
for whom dialysis access is being considered. Subsequent development
of subclavian vein stenosis or thrombosis would limit dialysis
access possibilities for that upper extremity.
Only 12% to 16% of patients who have upper extremity DVT
develop PE. 108,109 In comparison, 44% of patients who developed
proximal lower extremity DVT detected by sonography had a
subsequent PE diagnosed clinically. 110 Acute pulmonary emboli
in patients who have upper extremity DVT tend to occur in
untreated patients. 111,112 As expected, there is greater risk of PE
in catheter-related upper extremity DVT than in upper extremity
DVT from other causes. 113 Venous stasis and insuiciency caused
by venous thrombosis, more commonly seen with LE DVT, are
less common and less severe in the upper extremity. he deep
venous system in the arm has less exposure to the physiologic
hydrostatic high-pressure pump mechanism that is seen in
the lower extremity. 114,115 Development of extensive collateral
venous pathways in the arm and chest ater venous thrombosis
or obstruction contributes to these diferences and may cause
greater technical challenge in performing the upper extremity
venous Doppler examination, as compared with the lower
extremity.
Differentiation of Acute From Residual or Chronic
Venous Thrombosis
Findings suggesting residual or chronic DVT in the upper
extremity include ixed valve lealets, synechiae, ibrin sheaths,
small-caliber veins with noncompressible, thickened walls, and
multiple serpiginous veins not paralleling the artery (Fig. 27.47).
In some cases of residual or chronic thrombosis, the vein may
not be seen in the expected location owing to ibrosis or scarring.