[Irritable bowel syndrome and cardiac right-to-left shunt through a patent foramen ovale]

Both irritable bowel syndrome (IBS) and patent foramen ovale (PFO) have a similar prevalence in the general population, affect more commonly women and are related to comorbidities such as migraine. In IBS there are alterations in the metabolism of certain substances like serotonin. In the presence of PFO with a right- to left-shunt (RLS), a percentage of venous blood bypasses the lung filter and may increase these substances in blood.

A phone interview was done to determine the presence of IBS in patients previously attended for detection of RLS with transcranial Doppler ultrasound. The presence and grade of RLS was analyzed and compared with subjects without gastrointestinal symptoms (NoGI). Rome II criteria were used to diagnose IBS or other functional gastrointestinal disorder (FGD) and Venice 1999 consensus were used for the diagnosis of RLS.

Thirthy-three (18.3%) of 180 interviewed patients had IBS and 62 (34.4%) other FGD. RLS was found in 41% of NoGI patients, 64% of patients with IBS and 68% of patients with other FGD (odds ratio [OR] = 2.56; p < 0.05 for SII, and OR = 3.06; p < 0.01 for other FGD). RLS with a massive pattern was registered in en 27% of NoGI patients, 39% of patients with IBS and 45% of patients with other FGD (OR = 1.73; p = 1 for IBS, and OR = 2.21; p < 0.05 for other FGD).

We found a higher prevalence of cardiac RLS through a PFO in patients with IBS and other FGD. A possible etiopathogenic relationship must be considered in future studies.