Prevalence of mitral valve prolapse in primary spontaneous pneumothorax

Mitral valve prolapse (MVP) has been described as a common diagnosis and has been reported in 50% of patients with primary spontaneous pneumothorax (PSP). The purpose of this study was to determine the prevalence of MVP -- as diagnosed by 2D-echocardiography criteria -- in spontaneous pneumothorax.

A case-control study of 24 patients with PSP, and 40 age-matched controls. All cases underwent 2D-echocardiography by a certified cardiologist. Echocardiography and demographic features of both groups were compared and analyzed using Fisher's exact test. Classic MVP was defined as superior displacement of the mitral leaflets of more than 2 mm during systole and as a maximal leaflet thickness of at least 5 mm during diastasis, and non-classic prolapse was defined as displacement of more than 2 mm with a maximal thickness of less than 5 mm.

MVP was found in 9 of the 24 patients (37.5%) who suffered PSP, compared to 3 out of the 40 (7.5%) age-matched controls (P=0.008). The body mass index (BMI) (weight/height2) was lower in the group with pneumothorax (P=0.001).

In this study, applying an updated definition of MVP, the prevalence of MVP in PSP was lower than previously reported, but was still significantly higher than in the control group.