Serena J et al. (2008) Recurrent stroke and massive right-to-left shunt: results from the prospective Spanish multicenter (CODICIA) study. Stroke 71: 888–895

A new study has reported that the presence of a right-to-left shunt (RLSh) resulting from patent foramen ovale, regardless of its magnitude, does not seem to be a risk factor for recurrent stroke in patients with cryptogenic stroke. Previous studies have found that RLSh is associated with a first ischemic stroke, but few have assessed the contribution of this risk factor in stroke recurrence.

Serena and colleagues prospectively studied 486 patients with cryptogenic stroke (388 ischemic stroke, 98 transient ischemic attack) at 17 hospitals in Spain. Contrast transcranial Doppler imaging was used to detect the presence and magnitude of RLSh in patients while they performed the Valsalva maneuver. Transthoracic and/or transesophageal echocardiography, CT scan or MRI of the brain was also performed.

RLSh was observed in 297 (61.1%) patients, 200 (41.2%) of whom displayed a massive RLSh. Younger patients (<55 years old) were more likely than the cohort as a whole to exhibit a RLSh (70.7% vs 52.5%) in general or a massive RLSh (51.5% vs 31.9%). Over a mean follow-up of 729.2±410.8 days, stroke recurrence occured in 28 patients. Logistic-regression analysis revealed no association between massive RLSh and recurrent stroke in either the younger group or the whole cohort. Treatment type (anticoagulation or antiplatelet) did not affect the rate of stroke recurrence.

The authors discourage the use of potentially aggressive treatments, such as anticoagulation therapy, for the prevention of recurrence in patients with massive RLS and suggest that patent foramen ovale occlusion should be performed only within the framework of current clinical trials.