Until 2017, the Catheter to Vessel Ratio (CVR) had not been clearly defined in published literature. Today, it is recognized as:

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

CVR is now regarded as a critical factor for vascular access specialists and clinicians seeking to minimize the risk of catheter-associated thrombosis from interrupted flow dynamics.

Introducing CVR Calc 2.0 – the app that does the math for you

CVR Calc 2.0 is the newly updated iOS and Android application designed to calculate both linear and area-based differences between the external diameter of a catheter and the internal diameter of a venous or arterial vessel.

What’s new in Version 2.0 (scheduled iOS release date – September 20th, 2025):
– Expanded catheter sizes (1–16 French and 14–27 Gauge) including specific neonatal and pediatric sized catheters.
– Siri voice activation for iOS (Android voice support coming soon)
– Both linear and area-based measurements to 2 decimal places (Ver 1.0 only provided area-based calculations to 1 decimal), making all CVR calculations more accurate.
Added a widget for Control Center and the Lock Screen. With this, you can now jump straight to the app from the widget row. It’s also fully supported in Control Center.

Get the latest version from the and at the and add to you preferred phone/tablet platform today! Please feel free to share with you colleagues!