Central Vein Stenosis
Highlights
- CVS may remain asymptomatic because clinical symptoms and signs of CVS often develop only after an AVF or AVG is placed in the ipsilateral extremity and the impediment to increased blood flow is unmasked (View Highlight)
- The occurrence of CVS in HD patients has been reported on the ipsilateral side of the AV access without a history of previous CVC placement and is considered to be due to increased flow and abnormal shear stress on the side of access (View Highlight)
- Irrespective of the location (subclavian or internal jugular), a larger number and longer duration of CVC use increases the risk of developing CVS (View Highlight)
- the frequency and duration of CVC placement as being a more important determinant of CVS than the specific location. (View Highlight)
- A higher prevalence of CVS with catheters placed on the left rather than the right side may reflect the longer and more tortuous course required of a left-sided catheter (View Highlight)
- The course of left-sided CVCs is remarkable for at least 3 sites of sharp angles: at the transition from the left internal jugular vein to the left brachiocephalic (innominate) vein, at the midpoint of the left brachiocephalic (innominate) vein as it wraps around the mediastinal vessels, and at the junction of the left brachiocephalic (innominate) vein and the superior vena cava (View Highlight)
- Higher wall contact with a longer course, especially during physiologic movements associated with respiration, the cardiac cycle, and external movements, may result in increased endothelial injury that stimulates fibrotic pathways, thereby resulting in future CVS (View Highlight)
- cross-sectional area of the left internal jugular vein was much smaller than the right internal jugular vein in most healthy adults, potentially making the left side more vulnerable to CVS (View Highlight)
- External compression of the left brachiocephalic (innominate) vein by the mediastinal structures also may be responsible for CVS in some cases (View Highlight)
- An engorged subclavian vein can be compressed between the clavicle and first rib, causing hemodialysis-associated thoracic outlet syndrome (View Highlight)
- Smaller caliber CVCs (such as peripherally inserted central [PICC] and triple-lumen catheters) also can be associated with thrombus formation and CVS over a short term (View Highlight)
- CVS due to venous catheters most likely is related to heightened inflammation, increased oxidative stress, activation of leukocytes, release of myeloperoxidase, and activation of the coagulation cascade after catheter placement (View Highlight)
- The endothelial damage begins with the initial trauma from vein cannulation that is perpetuated by an indwelling foreign body that is not biocompatible. Further, constant movement of the catheter with respiration, movements of the head, and changes in posture, as well as increased flow and turbulence from the AV access, alter the shear stress, resulting in platelet deposition and venous wall thickening (View Highlight)
- Catheters frequently are associated with formation of a thrombus, often in conjunction with venous stenosis at the same site, although it is unclear whether the thrombus and the stenosis are causally related to each other (View Highlight)
- Not only does the formation of platelet thrombi and a thrombus at the tip of the catheter cause catheter dysfunction, but an adherent thrombus also may be the first step in the formation of a fibrin sleeve on the outer surface of the catheter. This process starts early, and a full-length sleeve can form as early as within a week (View Highlight)
- Autopsy finding of an adherent clot with intimal injury in patients with less than 14 days of catheter use and the presence of smooth muscle proliferation and thickened venous wall in those with more than 90 days of catheter use further support this hypothesis (View Highlight)
- Bioincompatibility of the intravascular device likely is one of the factors in the causation of venous injury and inflammation. Catheter material may have different levels of antigenicity, potential for tissue growth, and fibrogenesis (View Highlight)
- For an associated thrombus in the central vein, anticoagulation therapy is indicated, as suggested by available guidelines.70, 71 The catheter, if still functional, asymptomatic, and needed, should not be removed (View Highlight)