Juraj Dúbrava
The prevalence of patent foramen ovale (PFO) in nonselected adult population is approximately 25 %. Clinical studies have verified its importance in these situations: 1. cerebral ischaemic syndromes (stroke, transient ischemic attack – TIA, amaurosis fugax), 2. peripheral embolic syndromes, 3. migraine, 4. decompression illness in divers, high altitude flyers and astronauts, 5. platypnea-orthodeoxia syndrome. PFO has the main importance in patients with cryptogenic stroke / TIA, where it is found in 40 – 66 %. The high-risk PFO characteristics are: large PFO (≥ 4 – 6 mm), important right-to-left shunt, permanent shunt even without Valsalva manoeuver, the presence of atrial septal aneurysm, highly mobile atrial septum. The finding of PFO in the patient with stroke / TIA or with other possible manifestation must be judged cautiously. Their causal relation can be established only by team work of the cardiologist and the neurologist. In each case all other possible causes must be excluded. The diagnosis of stroke / TIA due to paradoxical embolism should be strongly considered in patients with proved PFO and right-to-left shunt and: clinical presentation and CT / MR finding of embolic attack, Valsalva manoeuver at the beginning of stroke / TIA, deep venous thrombosis, prothrombotic situations / thrombophilic states, concomittant pulmonary artery or peripheral artery embolism. The golden standard for diagnosing PFO is contrast transesophageal echocardiography.