The clinical diagnostic value of right-to-left shunt in cryptogenic stroke under right heart contrast echocardiography: a retrospective case-control study.

Background: About 30% of ischemic strokes do not have a clear cause, which is called cryptogenic stroke (CS). Increasing evidence suggests a potential link between CS and right-to-left shunt (RLS). RLS may lead to CS via paradoxical embolic mechanism. Hence, current study aims to explore the correlation between different RLS indexes and the occurrence of CS and its clinical diagnostic value in CS. Methods: A total of 117 patients diagnosed with CS from October 2020 to June 2024 were randomly collected, and 93 patients with only headache and dizziness were randomly collected as the control group. All patients underwent agitated saline contrast echocardiography (ASCE) and the semi-quantitative classification, type and duration of RLS were analyzed. Spearman correlation analysis was used to analyze the correlation between RLS grade and type and the occurrence of CS, and the correlation between RLS duration and RLS grade and type. The efficacy of different RLS grades, types and durations in the diagnosis of CS were analyzed by receiver operating characteristic (ROC) curve. Results: The included population ranged in age from 20-73 years, with 90 males and 120 females. There was no significant difference in basic data (e.g., gender, smoking history, drinking history, and the number of people with hypertension and diabetes) and serum biological indicators [triglyceride (TG), total cholesterol (TC), high-density lipoprotein (HDL) and low-density lipoprotein (LDL)] between the CS group and the control group (all P>0.05). The proportion of RLS (77.78%) in the CS group was significantly higher than that in the control group (35.48%) (P<0.001). Spearman correlation analysis showed that RLS grade (r=0.569) and type (r=0.346) were significantly correlated with the occurrence of CS (both P<0.001). In addition, RLS duration was significantly correlated with RLS type (r=0.902, P<0.001), but not with RLS size (P>0.05). ROC curve analysis showed that RLS grade had the highest area under the curve (AUC) in CS diagnosis, which was 0.807 [95% confidence interval (CI): 0.748-0.866], the diagnostic sensitivity was 68.4%, and the specificity was 87.1%. In addition, the diagnostic AUC of RLS type and RLS duration in CS were similar, at 0.700 (95% CI: 0.626-0.773) and 0.707 (95% CI: 0.634-0.780), respectively. Conclusions: RLS grade and RLS type are significantly correlated with the occurrence of CS. As an auxiliary means of CS diagnosis, RLS grade can effectively reduce the misdiagnosis rate of CS, which is of great clinical significance for early detection of CS risk.