Delayed Graft Function

The contract between this chapter and the reader.

1. 1. Define delayed graft function and slow graft function.
2. 2. Explain the ischemia-reperfusion mechanism of DGF.
3. 3. Identify the donor and recipient risk factors for DGF.
4. 4. Construct the differential of early graft dysfunction.
5. 5. Use Doppler to exclude vascular and urologic causes.
6. 6. Distinguish DGF from rejection and know when to biopsy.
7. 7. Manage DGF supportively, including immunosuppression adjustments.
8. 8. Recognise the prognosis and outcomes of DGF.
9. 9. Apply strategies that reduce DGF.

A sixty-second reading. Each bullet stands alone.

• Delayed graft function is commonly defined as the need for dialysis in the first week after transplant.
• It reflects acute tubular injury from ischemia-reperfusion: the graft is perfused but not yet functioning.
• Slow graft function is a sluggish recovery that does not require dialysis.
• Risk factors include a long cold ischemia time, DCD and extended-criteria donors, donor instability, and prolonged warm ischemia.
• The differential of early dysfunction spans pre-renal, vascular, urologic, and intrinsic causes.
• Doppler ultrasound confirms perfusion and excludes obstruction, separating DGF from vascular and urologic emergencies.
• DGF is expected when risk factors are present, the Doppler is reassuring, and there is no obstruction.
• Rejection can coexist with or masquerade as DGF, so biopsy is used when recovery is delayed or rejection is suspected.
• Management is supportive: maintain perfusion, avoid nephrotoxins, and dialyse as needed.
• Calcineurin-inhibitor exposure is often minimised or delayed during DGF.
• Most grafts with DGF recover function over days to weeks.
• DGF is associated with more acute rejection and somewhat worse long-term graft survival.
• Machine perfusion of the donor kidney reduces the rate of DGF.

The medical core. An expert should agree delayed graft function and early dysfunction are fully covered here.

Why it matters at the bedside

Agraft that does not work in the first days is alarming — but most often it is not failing, it is stunned. Delayed graft function is the recoverable injury of ischemia and reperfusion, and the clinical task is to recognise it for what it is, exclude the dangerous mimics, and support the kidney while it heals — without mistaking a stunned graft for a thrombosed one, or a rejecting one for a stunned one.

What DGF is

• Delayed graft function is most commonly defined as the need for dialysis within the first week after transplant. Mechanistically it is acute tubular injury: the graft is perfused but its tubules are too injured to produce useful urine yet. Slow graft function is the milder cousin — a sluggish recovery that never quite needs dialysis — and immediate function is the prompt diuresis of a healthy, low-ischemia graft.

The ischemia-reperfusion mechanism

• DGF is the clinical face of ischemia-reperfusion injury. Cold storage and warm ischemia injure tubular cells; reperfusion adds an oxidative and inflammatory insult; the result is acute tubular injury that impairs function for days to weeks until the tubular epithelium regenerates. Because the injury is to tubules — not vessels — the graft remains perfused, which is the key to telling DGF apart from a vascular catastrophe.

Risk factors

• DGF is largely predictable from the donor. A long cold ischemia time is the dominant, partly modifiable factor; donation after circulatory death (with its warm ischemia), extended-criteria and high-KDPI donors, donor acute kidney injury or haemodynamic instability, and a prolonged anastomosis time all raise the risk. Living-donor, short-cold-time kidneys rarely suffer it.

The differential of early dysfunction

• Early graft dysfunction is not synonymous with DGF — it is a differential. Pre-renal causes (hypovolemia, hypotension) starve the graft of flow; vascular causes (arterial or venous thrombosis) cut it off; urologic causes (leak, obstruction) block the outflow; and intrinsic causes include DGF/acute tubular injury (much the most common when risk factors are present), rejection (including antibody-mediated), and calcineurin-inhibitor toxicity. The discipline is to work through this list, not to assume.

Using Doppler to exclude emergencies

• Doppler ultrasound is the pivot of the early assessment: it confirms arterial and venous perfusion (absent flow means thrombosis, a surgical emergency) and excludes obstruction and peri-graft collections. A reassuring Doppler — a perfused, unobstructed kidney — in a patient with DGF risk factors points firmly to DGF and away from the emergencies.

DGF versus rejection and when to biopsy

• DGF and rejection are not mutually exclusive — and DGF makes rejection harder to detect, because there is no rising urine output or falling creatinine to monitor. So when DGF does not recover on the expected timeline, or rejection is otherwise suspected, the graft is biopsied; many programmes biopsy persistent DGF on a schedule precisely to catch the rejection that DGF can hide.

Supportive management

• DGF has no specific cure — management is to protect the healing kidney. Maintain perfusion and a sensible volume status, scrupulously avoid nephrotoxins, and provide dialysis as needed for the fluid, potassium, and uremic consequences while the tubules recover. Identified vascular or urologic causes are treated surgically; DGF itself is supported and given time.

Immunosuppression in DGF

• Calcineurin inhibitors are themselves nephrotoxic and can deepen tubular injury, so during DGF their exposure is often minimised, delayed, or reduced — sometimes with a lymphocyte-depleting induction that allows calcineurin-inhibitor introduction to be postponed — balancing the need to prevent rejection against the harm of adding injury to an already-injured graft.

Prognosis and outcomes

• The reassuring truth is that most grafts with DGF recover and go on to function. The cautionary truth is that DGF is associated with more acute rejection, longer hospital stays, and somewhat worse long-term graft survival — so it is recognised and managed seriously, not dismissed, even as the patient is reassured that recovery is the usual outcome.

Reducing DGF

• Because DGF is driven by ischemia, the levers to reduce it are about ischemia: minimising cold ischemia time, careful donor and recipient management, and — with good evidence — hypothermic machine perfusion of the donor kidney, which lowers the rate of DGF compared with static cold storage.

Five fully-built tables.

Table A — Early function patterns

Table B — Risk factors for DGF

Table C — The differential of early dysfunction

Table D — Management of DGF

Table E — Outcomes and prevention

Visualise & Map

Causal chains, each ending in a named action.

Chain 1 — Ischemia to recovery

Cold + warm ischemia and reperfusion → acute tubular injury → a perfused but non-functioning graft → recovery as tubules regenerate → ACTION: support the graft and expect recovery over days–weeks.

Chain 2 — The ischemia dose

Long cold ischemia time / DCD → greater tubular injury → higher DGF risk → ACTION: minimise ischemia time and use machine perfusion.

Chain 3 — Perfused but not working

DGF injures tubules, not vessels → the graft stays perfused → distinguishable from thrombosis (no perfusion) → ACTION: use Doppler to separate DGF from a vascular emergency.

Chain 4 — The masking effect

DGF removes the urine-output and creatinine signals → rejection becomes clinically silent → it can hide within DGF → ACTION: biopsy persistent DGF to detect rejection.

Chain 5 — Adding injury to injury

Calcineurin inhibitors are nephrotoxic → high exposure deepens tubular injury in DGF → delayed recovery → ACTION: minimise or delay calcineurin-inhibitor exposure during DGF.

Numbered rules. These numbers are the cross-reference handle for the cases and flowcharts.

Clinical Reasoning

Five cases. Each stops you at a decision before it answers it.

Every mechanism from Level 3 earns a bedside consequence and an action.

Exhaustive. Every rule in the chapter is here.

Safety & Evidence

Panel A — Red flags

Panel B — NEVER DO

Anti-patterns clinicians fall into. Each becomes a Level 22 distractor.

The grade reflects strength of evidence, not importance.

Patient Decisions

Outcomes as natural frequencies. Figures are representative; the direction of effect is given where precise numbers are uncertain.

Apply & Test

Copy-paste chart notes that map to the real decisions in this chapter.

Template 1 — DGF assessment note

• Function pattern: immediate / slow / delayed (dialysis needed in week 1).
• Risk factors: cold ischemia time ___; DCD/ECD ___; donor AKI ___.
• Differential excluded: pre-renal (volume) ___; vascular/urologic (Doppler) ___.
• Doppler: perfusion present; no obstruction/collection ___.
• Working diagnosis: DGF / other; biopsy planned if not recovering ___.

Template 2 — DGF management note

• Support: perfusion/volume; nephrotoxins avoided.
• Immunosuppression: CNI minimised/delayed ___; induction cover ___.
• Dialysis: required? schedule ___.
• Recovery: trend (urine output / creatinine) ___.
• Biopsy (if not recovering): result and action ___.

Pre-rounds compression. Rules only.

Active recall. At least one card per objective.

Micro-teaching for rounds. Two scenarios, five steps each.

Nine items, each anchored in this chapter. At least one per objective.