Cryptogenic strokes are common in young adults. Patent foramen ovale (PFO) is an important cause of cryptogenic ischemic strokes. Transcranial Doppler (TCD) with bubble contrast is a noninvasive bedside tool in screening for PFO and other right to left shunt (R-L shunt). Percutaneous PFO closure in selected patients with a high risk for paradoxical emboli is beneficial. Data on PFO in young cryptogenic strokes from India are limited.
To determine the utility of screening for R-L shunt using TCD in young patients with cryptogenic strokes and to identify clinical predictors of an R-L shunt.
This was a hospital-based prospective study conducted between January 2013 and December 2019 in a tertiary hospital in South India. All consecutive patients with ischemic stroke and ages between 18 and 45 years were included. TCD with bubble contrast study was performed on all patients. Those who were TCD bubble contrast study positive and had features of an embolic stroke of undetermined source (ESUS) underwent transesophageal echocardiography (TEE) to confirm a PFO and to look for its high-risk features. Selected ESUS patients with PFO and associated high-risk features as identified on TEE underwent percutaneous PFO device closure. All patients were followed up in the stroke and cardiology clinics.
During the study period, 6,197 patients with ischemic strokes were screened for eligibility of which 304 (4.9%) were between the age of 18 and 45 years. Of these, 300 patients with ischemic stroke in young underwent the TCD bubble contrast study. R-L shunt was found in 121 (40.3%) patients. Based on an extensive etiological evaluation, 72 patients were identified to have an ESUS and underwent TEE for confirming PFO. Of these, 65 patients had PFO, four were negative, and three were found to have extracardiac shunts. Based on clinical findings, imaging features, and high-risk features on TEE, 29 patients underwent PFO closure. Activity at the time of stroke onset equivalent to a Valsalva maneuver (p ≤ 0.01), isolated cortical infarction (p = 0.027), and posterior circulation involvement (p = 0.0135) were significantly associated with the presence of an R-L shunt. The patients who had a higher modified anatomical-functional risk of paradoxical embolism (AF-RoPE) score, a high-grade shunt on the TCD bubble contrast study had a longer length of the tunnel and had the presence of an interatrial septal aneurysm (p = 0.012) were referred for PFO device closure.
R-L shunt is common in cryptogenic ischemic strokes in young. TCD with bubble contrast study is a noninvasive and feasible bedside tool to detect them. Applying the ESUS criteria in these cryptogenic strokes with a positive TCD bubble contrast study can be then used for selecting patients for more invasive tests like TEE. High-risk PFOs picked up with TEE can be then considered for PFO closure for secondary stroke prevention. The history of Valsalva maneuver-like activity (such as lifting heavy weights or straining) at the time of stroke onset can be a clinical predictor for the presence of an R-L shunt. In addition to isolated cortical infarction, the presence of posterior circulation infarct in ESUS can predict the presence of an R-L shunt.

© Journal of the Association of Physicians of India 2011.