Background & methods

Every Artisse size at a glance

Each Artisse size settles at a different compressed height as it is squeezed into a narrower aneurysm. This map plots that width-to-height relationship for all twenty devices at once — the continuum a fixed printed table can never list in full. Every curve is reconstructed from just the two published Medtronic shapes (the dots on each line); exactly how that reconstruction works is set out step by step below.

How the height is calculated

01 — The two known points

The sizing sheet gives only two shapes per device

Everything below is built from four numbers per device — a, b, c and d. None of them is fitted or invented: all four are read straight off the Medtronic Artisse sizing sheet (CA-CTL-0677-E). Two are widths, two are heights.

Each row of the sheet therefore gives two shapes of the same device: (b, c) in air, and (a, d) squeezed into its widest rated sac — narrower, and correspondingly taller. Two points, two unknowns, which is what makes the fit in step 03 exact. Heights anywhere between those two widths, and below a, are not published.

Worth knowing: a always sits about 25% below b (24.0–25.5% across all 20 rows) and depends only on the nominal width — every 6.0 mm device has a = 4.5 mm whatever its height. The sheet’s maximum aneurysm width is in effect a 25% width-oversizing rule, so d is the only independently measured second point.

02 — The model

Braid filament-length conservation

An Artisse device is a braided nitinol mesh. The wires don't stretch, so squeezing the device narrower forces it taller — the total filament length is conserved. Treating the braid as a scissor/pantograph mesh gives a Pythagorean relation between height H and width W:

α is a shape constant set by the braid angle and crossing density; L is proportional to the conserved filament length. A smaller W forces a larger H.

03 — Fitting the curve

α and L are solved from the two points

Two known points fix the two unknowns exactly. Setting the in-air state equal to the compressed state:

Because d > c and b > a, α² is always positive, and by construction the fitted curve passes exactly through both published points.

04 — Reading any width

Height at an arbitrary aneurysm width

At w = a this returns the published d; at w = b it returns the in-air c; between them it falls smoothly, and below a it rises — that rise is the over-compression extrapolation.

Worked example, Artisse 6.0 × 4.0 (b = 6.0, c = 4.0, a = 4.5, d = 6.2): α² = (6.2² − 4.0²) / (6.0² − 4.5²) = 22.44 / 15.75 = 1.425 and L² = 4.0² + 1.425 · 6.0² = 67.29. Then H(4.5) = √(67.29 − 1.425 · 4.5²) = 6.2 mm, the published compressed height, and H(6.0) = 4.0 mm, the in-air height. A 5.0 mm sac falls in between: H = √(67.29 − 35.62) = 5.6 mm.

05 — % compressed Artisse width

The compression column

This column reports how much narrower than nominal the Artisse device is at the current width, as a percentage of its in-air width (radial compression):

It reads 0% at nominal width b and rises as the device is squeezed; at the rated max sac a it equals (b−a)/b.

06 — The ± deltas

Over/under-sizing next to width and height

The small figure under each width is the width oversizing — how much wider the nominal device is than the sac it sits in, b − w, always positive and echoing the sheet's +1 / +1.5 / +2 guide. The figure under each height appears once you enter a sac height: it is the coverage delta, H(w) − sac height — positive (teal) means the device stands taller than the dome (the IFU's neck-coverage condition), negative (amber) means it would come up short.

07 — Matching an aneurysm

How sizes are recommended

Entering a sac width sets every device's deployed width to that value (the braid conforms to the cavity), so each row shows the height that device would take in that sac. Each device is then judged on two things together — how far it protrudes into the neck (compressed height minus sac height) and how much its width is compressed. A size is a candidate fit when protrusion is in the working range and width compression is positive: a good fit protrudes 0.5–1.0 mm; an acceptable fit protrudes a shallower 0.2–0.5 mm, allowed only when width compression reaches ≥20% to compensate. A flush 0%-compression size is never recommended (no radial apposition).

Up to three suitable devices are marked with a single star (★); the lead pick — named in Consider… — carries a slightly stronger highlight. For a narrow sac the lead pick is the candidate with the greatest width compression. For a sac wider than 4 mm the lead pick instead targets the size whose protrusion lands closest to ≥1 mm, since a wider sac seats more securely with a little more neck protrusion. Protrusion beyond 1.0 mm is not a good or acceptable fit, but when nothing reaches the working range the single closest size with positive compression and protrusion is still offered — even if it sits just past the ceiling; a lead pick protruding more than 1.5 mm is flagged protrusion may be too high. Devices narrower than the sac (which cannot reach it) are dimmed as undersized.

08 — The slider scale

Why thumb travel ≠ millimetres

Each slider is normalized so the rated max a sits at the same 25% position on every row — that's what lines the knobs up at rest. The fixed left quarter is the 0.5 mm over-compression zone (w from a−0.5 to a); the right three-quarters is that device's working range (w from a to b).

09 — Caveats

What to keep in mind

• Only the two endpoints are real Medtronic data. Everything in between, and the entire sub-[a] zone, is an engineering estimate.
• The radiopaque markers in the graphic are schematic placeholders at the device poles for illustration — not the true marker count or positions of the Artisse device.
• The published d values are rounded to 0.1 mm, so the fitted α is not identical across the matrix (≈1.13 for the smallest devices up to ≈1.35 for 8.0 mm) — expected for a real, non-ideal braid.
• Real devices have a compression floor where the mesh densifies and stops elongating, so the deepest part of the over-compression zone is the least trustworthy.
• Anything left of the tick is below the rated envelope and therefore off-label.

About the values: Only the two endpoints per device come from the Medtronic Artisse sizing sheet (CA-CTL-0677-E) — the tick = rated max average aneurysm width [a] (height = published compressed height [d]), and the slider's right end = nominal width [b] (height = in-air height [c]). Everything in between, and the entire sub-[a] zone, are unvalidated estimates from a simplified braid model; they are not Medtronic figures and have not been clinically verified. The device silhouette and radiopaque markers are schematic. Always confirm sizing against the current Instructions for Use and your own measurements. This tool is not affiliated with, sponsored, or endorsed by Medtronic; Artisse is a trademark of Medtronic. Official reference chart: Medtronic Artisse wallchart (EN-GB, PDF).