Lung outcomes are worst at both ends of the ischemic-time curve.
The relationship between cold-ischemia duration and early graft failure is U-shaped, not a simple line — best in a mid-range window and elevated at both extremes. The short-time paradox is a confound worth naming; the long tail is the causally plausible, modifiable one.
Source: OPTN/UNOS STAR file, Dec 2025 release · lung/heart-lung transplants with recorded ischemic time and ≥1-year graft-status follow-up.
15% ↑ 20%
One-year graft failure is lowest at 5–6 h (14.6%) and rises to 20.1% beyond 10 h — but is also elevated (18.0%) under 4 h. Median ischemic time is 5.3 h.
01 · A U-shaped curve
Failure is elevated at both extremes
Crude one-year graft-failure rate by cold-ischemia band, among transplants observed through one year (failed ≤365 d or ≥365 d follow-up). The curve dips in the middle and rises at both ends.
1-year graft failure (%)
Read the short-time end with caution. The elevated failure under 4 h almost certainly reflects confounding by indication — very short ischemia clusters with urgent, local, sicker recipients — not a harm of speed. The long tail (>8 h) is the causally plausible, modifiable signal.
02 · Where transplants sit
Most lungs are implanted at 4–8 hours
Lung transplants by ischemic time (count)
Faster, more confident accept decisions shorten cold ischemia in the tail. An objective offer-time CT read reduces back-and-forth on borderline organs — compressing the >8 h fraction where failure climbs.