Vascular sheath (IR)

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A vascular sheath is a short, hollow, flexible tube inserted into an artery or vein to provide secure vascular access during interventional procedures.

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It serves as a conduit for the insertion and exchange of wires, catheters, balloons, and devices, while maintaining hemostasis via an inbuilt valve.

Core Components of a Vascular Sheath

Component	Function
Sheath body	The outer tube placed inside the vessel
Dilator	A tapered stiff inner piece that facilitates entry
Hemostatic valve	Prevents back-bleeding while allowing wire/catheter manipulation
Side port (side arm)	Allows continuous flushing or pressure monitoring
Y-connector / Tuohy-Borst adapter	Used in long sheaths for endovascular cases

Sheath Sizes

Parameter	Typical Range
Size (French)	4 Fr to 24 Fr (1 Fr = 0.33 mm)
Length	Short (10 cm) to long (45–90 cm), depending on the target site

Common sizes in diagnostic IR: 4–6 Fr
Larger sheaths (≥12 Fr) used for EVAR, TIPS, thrombectomy, valve procedures

Types of Sheaths

1. Short Vascular Sheaths (Introducer Sheaths)

Use	Typical Size	Examples
Routine arterial/venous access	4–7 Fr	Terumo Radifocus, Merit Prelude
Diagnostic angiography	4–6 Fr	Brachial or femoral access

2. Long Sheaths / Guiding Sheaths

Use	Typical Size	Examples
Complex interventions	6–12 Fr	Flexor (Cook), Destination (Terumo)
TIPS, iliac, renal stenting	Long (25–55 cm)	Often with steerable tips

3. Sheaths with Steerable or Shaped Tips