Incidence and Factors Associated with Thrombus Development
We report that in 290 patients with a CVC tip seated in the RA,
incidental detection of RAT by clinically indicated TTE was 5.2%. To
the best of our knowledge, this study is the largest series in which an
incidence of catheter-associated RAT has been reported in patients with
a catheter tip seated in the RA. Previous estimates of incidence range
from 8.8-24% in cancer patients, 5.4% in hemodialysis patients, and
nearly 30% as detected by autopsy in patients who died with a CVC
present.3,9-12 However, these estimates were not
specific for patients in whom the catheter tip is specifically present
in the RA. Plodkowski et al noted that catheter-associated RAT is
associated with the extent to which the catheter protrudes into the
RA.12 Similarly, Gilon et al found a strong
association between RAT and catheter tip placement in the RA as opposed
to the cavoatrial junction or SVC.3 However, other
studies have reported that catheter tip placement in the cavoatrial
junction may not prevent RAT in comparison to placement in the
RA.11,13 CVC catheters placed distally in the RA may
encounter more “swirling” or turbulent blood flow and predispose to
thrombus formation compared to catheters in the SVC in which the venous
vessel wall may facilitate more laminar blood flow.
Our study confirms that the placement of a catheter tip in the RA
entails a risk for RAT, raising concerns regarding institutional
practices that may feature variations in recommended CVC insertion
depth. Myriad complex factors may guide these practices such as
balancing the potential for complications with achievement of the best
possible infusion flow.14 Our study shows that the
possibility of RAT when CVC protrudes beyond cavoatrial junction should
be considered. Furthermore, our study demonstrates the ability of
clinically indicated TTE to incidentally detect RAT.