Objective: To test the effect of patent foramen ovale (PFO) closure on neurological events in divers.
Design: Prospective, non-randomised, longitudinal three-arm study.
Setting: Tertiary referral centre.
Population: 104 scuba divers with a history of major decompression illness (DCI).
Intervention: Transcutaneous PFO closure.
Main outcome measures: Baseline and three follow-up examinations with a questionnaire about health status and diving habits/accidents, transoesophageal echocardiography at baseline for PFO grading, cerebral MRI at all examinations.
Results: 39 divers had no PFO, 26 had a PFO and chose to undergo percutaneous closure and 39 had a PFO, but decided not to undergo closure. The total number of dives, including those performed before baseline and those during long-term follow-up, was 81,654; 18,394 dives during the follow-up period of 5.3 ± 0.3 years, during which there were a total of five major neurological DCI events-namely 0 in the no PFO group, 0.5 ± 2.5/10⁴ dives in the PFO closure group and 35.8 ± 102.5/10⁴ dives in the PFO no closure group (four events; p = 0.045 between the PFO groups). In the groups, no PFO, PFO closure and PFO no closure, there were 1.1 ± 2.6, 0.8 ± 1.4, 3.3 ± 6.9 ischaemic brain lesions, respectively, at follow-up (p = 0.039 between the PFO groups)-that is, 16 ± 42/10⁴ dives in the no PFO group, 6 ± 13/10⁴ dives in the PFO closure group and 104 ± 246/10⁴ dives in the PFO no closure group (overall p = 0.042; p = 0.024 between the PFO groups).
Conclusion: PFO closure in continuing divers appears to prevent symptomatic (major DCI) and asymptomatic (ischaemic brain lesions) neurological events during long-term follow-up.