Catheter to vessel ratio (CVR) may be defined as the

indwelling space or area consumed or occupied by an intravascular device inserted and positioned within a venous or arterial blood vessel.”

The CVR is an extremely important assessment factor for all vascular access specialists and like-minded clinicians placing intravascular devices.

Catheter-related thrombosis (CRT) poses a serious, yet challenging situation for clinical providers working within todays current healthcare environment. The clinical issues generated by this phenomenon are problematic and often lasting well beyond the initial diagnosis and potential treatment protocols. With short and long-term issues for both patients and clinicians, such as catheter dysfunction, infection, and superior vena cava (SVC) syndrome, accompanied by the considerable costs of ongoing treatment and care, several clinical conundrums, particularly when there are varying thoughts and evidence on how-to-treat within this topic, exist. Vascular access (VA) devices continue to be the most frequently performed invasive procedure in any given healthcare institution today, and the potential for CRT increases with many contributing factors, not to mention the comorbidities that impact thrombosis risk on a pathophysiological level.

Magnitude of the problem.

Upper extremity-deep vein thrombosis (UE-DVT) refers to the formation of a thrombus within the deep vessels of the upper arm and chest: primarily the subclavian, axillary and brachiocephalic veins, but also the basilic, brachial, and the more increasingly, superficial cephalic veins, in the arm. It has been described as either idiopathic (primary) due to anatomical variants or as secondary, more associated with tumor disease, intravenous catheters, and pacemaker leads [1].

Much focus on this phenomenon has targeted the increased use of peripherally inserted central catheters (PICCs) in the last two decades [2-8] especially with its increasing demand for non-physician facilitated insertions [9-11]. Around this time, a prospective study looking at triple lumen PICCs highlighted a symptomatic thrombosis risk of 20% that was considered unacceptably high by the study oversight committee. The study was terminated due to patient risk. Venous thrombosis (symptomatic or asymptomatic) was detected in 26 of 45 patients (58%) when examined with ultrasound (US) [12].

Catheter-related thrombosis has serious implications related to the loss of vascular access, development of pulmonary embolism (PE), recurrent VTE, infections and post-thrombotic syndrome. The pathogenesis of CRT is complex and multifactorial, with risk factors associated with the catheter, the vessel selected for insertion and the underlying patient co-morbidities and their treatments. The monitoring of the catheter to vessel ratio (CVR), whereby vessel and catheter size are measured for relationship appropriateness, may have potential influence on CRT, by potentially reducing venous stasis through improving flow dynamics around the body of the catheter.

Timothy R. Spencer & Keegan J. Mahoney (2017). Reducing catheter-related thrombosis using a risk reduction tool centered on catheter to vessel ratio. Journal of Thrombosis and Thrombolysis, 44(4): 427-434

I have put up a PDF version for download of our award winning poster from the Association for Vascular Access 31st Scientific Meeting held in Phoenix, AZ, USA.

Click the link posted below to open and save a copy of our poster that can be used to help make the best decision for appropriateness of catheter diameter and vessel size to help prevent catheter-related thrombosis.

Here are some images from the Association for Vascular Access 31st Scientific Meeting ePoster Theatre session where we presented our research.


Catheter Vessel Ratio – What Next – AVA (iPosterSessions) – PDF

  1. Heil J, Miesbach W, Vogl T, Bechstein WO, Reinisch A. Deep Vein Thrombosis of the Upper Extremity: A Systematic Review. Deutsches Ärzteblatt International. 2017 Apr;114(14):244.
  2. Elman EE, Kahn SR. The post-thrombotic syndrome after upper extremity deep venous thrombosis in adults: a systematic review. Thrombosis research. 2006 Dec 31;117(6):609-14.
  3. King MM, Rasnake MS, Rodriguez RG, Riley NJ, Stamm JA. Peripherally inserted central venous catheter-associated thrombosis: retrospective analysis of clinical risk factors in adult patients. Southern medical journal. 2006 Oct 1;99(10):1073-8.
  4. Evans RS, Sharp JH, Linford LH, Lloyd JF, Tripp JS, Jones JP, Woller SC, Stevens SM, Elliott CG, Weaver LK. Risk of symptomatic DVT associated with peripherally inserted central catheters. CHEST Journal. 2010 Oct 1;138(4):803-10.
  5. Cotogni P, Pittiruti M. Focus on peripherally inserted central catheters in critically ill patients. World journal of critical care medicine. 2014 Nov 4;3(4):80.
  6. Chopra V, Ratz D, Kuhn L, Lopus T, Lee A, Krein S. Peripherally inserted central catheter‐related deep vein thrombosis: contemporary patterns and predictors. Journal of Thrombosis and Haemostasis. 2014 Jun 1;12(6):847-54.
  7. Greene MT, Flanders SA, Woller SC, Bernstein SJ, Chopra V. The association between PICC use and venous thromboembolism in upper and lower extremities. The American journal of medicine. 2015 Sep 30;128(9):986-93.
  8. Holder MR, Stutzman SE, Olson DM. Impact of Ultrasound on Short Peripheral Intravenous Catheter Placement on Vein Thrombosis Risk. Journal of Infusion Nursing. 2017 May 1;40(3):176-82.
  9. Alexandrou E, Spencer TR, Frost SA, Parr MJ, Davidson PM, Hillman KM. A review of the nursing role in central venous cannulation: implications for practice policy and research. Journal of clinical nursing. 2010 Jun 1;19(11‐12):1485-94.
  10. Ramirez C, Malloch K, Agee C. Evaluation of respiratory care practitioner central venous catheter insertion program. The Journal of the Association for Vascular Access. 2010 Jan 1;15(4):207-11.
  11. Johnson D, Snyder T, Strader D, Zamora A. Positive Influence of a Dedicated Vascular Access Team in an Acute Care Hospital. Journal of the Association for Vascular Access. 2017 Mar 31;22(1):35-7.
  12. Trerotola SO, Stavropoulos SW, Mondschein JI, Patel AA, Fishman N, Fuchs B, Kolansky DM, Kasner S, Pryor J, Chittams J. Triple-lumen peripherally inserted central catheter in patients in the critical care unit: prospective evaluation. Radiology. 2010 Jul;256(1):312-20.

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