Interventional Radiology · Complications and quality assurance · Modified CIRSE 2026

Modified CIRSE Classification of Complications

Grades complications of image-guided procedures according to procedural completion, additional treatment, hospitalisation, permanent sequelae and death.

Purpose

To provide a standardised, outcome-focused system for reporting complications following image-guided minimally invasive procedures.

Grade	Description
1a	Complication resolved during the same procedural session and the intended procedure was completed; no additional post-procedural treatment, sequelae or deviation from the expected post-procedural course.
1b	Complication resolved during the same procedural session, but the intended procedure was not completed; no additional post-procedural treatment, sequelae or deviation from the expected post-procedural course.
2	Prolonged observation, including an unplanned overnight stay of less than 48 hours; no additional post-procedural treatment or sequelae.
3a	Additional post-procedural treatment or hospitalisation for more than 48 hours but less than 2 weeks; no permanent sequelae.
3b	Additional post-procedural treatment or hospitalisation for more than 2 weeks; no permanent sequelae.
4	Permanent mild sequelae, but the patient can resume work and live independently.
5	Permanent severe sequelae requiring ongoing assistance with daily activities or additional long-term treatment.
6	Death.

How to use it

The modified system subdivides Grades 1 and 3, while Grades 2 and 4–6 retain the original structure.
Grade 1a means the complication was resolved and the intended procedure was completed; Grade 1b means the procedure could not be completed.
Grade 3 has no permanent sequelae: 3a indicates hospitalisation for more than 48 hours but less than 2 weeks, whereas 3b indicates hospitalisation for more than 2 weeks.
Grades 4 and 5 are defined by permanent functional consequences; Grade 6 is death.
The system can be applied immediately after an intervention or retrospectively for audit and research reporting.

Common mistake

Do not assign Grade 1a merely because an intraprocedural complication was successfully controlled. If the complication prevented completion of the intended procedure, it is Grade 1b.

Exam pearl

Remember the key modifications: Grade 1 is divided by whether the intended procedure was completed, and Grade 3 is divided by whether hospitalisation was shorter or longer than 2 weeks.

Viva questions

What is the purpose of the modified CIRSE complication classification?: It standardises reporting of complications after image-guided procedures using procedural completion, additional treatment, hospitalisation, permanent sequelae and death.
Which grades were subdivided in the modified CIRSE classification?: Grades 1 and 3 were subdivided. Grade 1 became 1a and 1b, while Grade 3 became 3a and 3b.
How do Grades 1a and 1b differ?: In both, the complication is resolved during the same session without additional post-procedural treatment or sequelae. The intended procedure is completed in Grade 1a but not completed in Grade 1b.
What constitutes a Grade 2 complication?: Grade 2 requires prolonged observation, including an unplanned overnight stay of less than 48 hours, without additional post-procedural treatment or sequelae.
How are Grades 3a and 3b distinguished?: Both may require additional treatment and have no permanent sequelae. Grade 3a involves hospitalisation for more than 48 hours but less than 2 weeks, whereas Grade 3b involves hospitalisation for more than 2 weeks.
How do Grades 4, 5 and 6 differ?: Grade 4 causes permanent mild sequelae compatible with independent living and return to work. Grade 5 causes permanent severe sequelae requiring ongoing assistance or long-term treatment, and Grade 6 is death.
An intraprocedural complication is controlled, but the planned treatment is abandoned. What is the grade?: This is Grade 1b because the complication was resolved during the same session but prevented completion of the intended procedure.