Higher LA pressure may prevent opening of patent foramen ovale in acute ischemic stroke patients with atrial fibrillation.

BACKGROUND AND PURPOSE

Detection rate of right-to-left shunt (RLS) may be lower in stroke patients with atrial fibrillation (AF) than in those without AF. This may be due to the mechanism of embolic stroke in AF patients that involves cardiac embolus rather than paradoxical embolism due to RLS. Patients with AF frequently have subclinical heart failure, resulting in elevated left atrial (LA) pressure, which may prevent opening of a patent foramen ovale (PFO). We aimed to investigate whether the detection rate of RLS in stroke patients with AF was affected by elevated LA pressure.

METHOD

We enrolled consecutive acute stroke patients with AF and, as controls, consecutive acute stroke patients without AF. RLS was diagnosed using contrast transcranial Doppler. To assess LA pressure, the ratio of early mitral inflow velocity to diastolic mitral annular velocity (E/E') was measured using transthoracic echocardiography.

RESULT

We enrolled 171 patients with AF (AF group, age, 78 years [IQR, 70-83]) and 171 patients without AF (control group, age, 73 years [IQR, 64-81]). RLS was observed less frequently in AF patients than in the control group (9% vs. 18%, p=0.024). E/E' ratio was higher in AF patients (13.1 [9.4-17.4] vs. 10.9 [8.2-13.7], p<0.001). Among controls, E/E' ratio did not differ between patients with and without RLS (11.8 [8.5-12.9] vs. 10.8 [8.0-13.9], p=0.884). Conversely, in AF patients, E/E' ratio was lower in patients with RLS than in those without RLS (9.0 [8.3-12.6] vs. 13.6 [10.2-18.1], p=0.008). Multivariate regression analysis demonstrated that E/E' ratio of <11.0 was an independently associated with RLS (OR 4.61, 95%CI 1.21-17.62, p=0.025).

CONCLUSION

RLS was detected less frequently in AF patients than in controls. Elevated LA pressure was associated with the absence of RLS in AF stroke patients and may prevent opening of a PFO.