Abstract
Patent foramen ovale (PFO) has been considered a potential mechanism of embolic stroke of undetermined origin. The aim of the present study was to identify the features of the right-to-left shunt (RLS) in patients with undetermined embolic ischemic stroke and compare them with those of patients with non-cardioembolic ischemic stroke. A retrospective study was conducted with 168 patients with stroke and RLS separated into the following two groups: the undetermined embolic stroke group (UES group) and non-cardioembolic stroke group (NCES group). All patients were assessed by transcranial Doppler to evaluate the presence and quantification of microembolic signals (MES) at rest and under Valsalva maneuver. Of all patients evaluated in the current study, 96 were included in the UES group and 72 in the NCES group. In the UES group, 65 patients had RLS with ≥10 MES (67.7%), which was higher than that observed in the NCES group (51.4%, p=0.038). According to the moment of the cardiac cycle, 75 patients (78.1%) in the UES group had a positive test at rest compared to 42 (58.3%) in the NCES group (p=0.007). The current study demonstrated that almost 70% of patients with undetermined embolic stroke and PFO presented a large RLS and more than 75% had RLS at rest. These findings suggest that the size of the shunt should be taken into account when evaluating whether PFO could be a possible mechanism underlying cryptogenic stroke.
Highlights
Up to 30% of all ischemic stroke events are of undetermined etiology[1]
Of the 168 patients with ischemic stroke and right-to-left shunt (RLS) evaluated in the current study, 96 were included in the UES group and 72 in the NCES group
Eight patients (12.5%) had discordant tests results, with a negative RLS in transesophageal echocardiography (TEE) and positive RLS in contrast transcranial Doppler (c-TCD), which can be explained by increased sensitivity of the c-TCD
Summary
Up to 30% of all ischemic stroke events are of undetermined etiology[1]. Paradoxical embolism, related to a right-toleft shunt (RLS) through a patent foramen ovale (PFO), is one of the possible mechanisms[2,3,4].PFO, a persistent congenital opening in the interatrial septum, is found in about 25% of the adult population[5]. The aim of the present study was to use c-TCD to identify the features of RLS in patients with embolic cryptogenic ischemic stroke and compare with findings of patients with non-cardioembolic ischemic stroke. Patent foramen ovale (PFO) has been considered a potential mechanism of embolic stroke of undetermined origin.Objective: The aim of the present study was to identify the features of the right-to-left shunt (RLS) in patients with undetermined embolic ischemic stroke and compare them with those of patients with non-cardioembolic ischemic stroke. Conclusions: The current study demonstrated that almost 70% of patients with undetermined embolic stroke and PFO presented a large RLS and more than 75% had RLS at rest These findings suggest that the size of the shunt should be taken into account when evaluating whether PFO could be a possible mechanism underlying cryptogenic stroke
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