The diagnostic value of contrast-enhanced transcranial Doppler and contrast-enhanced transthoracic echocardiography for right to left shunt in patent foramen ovale: a systematic review and meta-analysis

Purpose: To evaluate and compare the diagnostic value of contrast-enhanced transcranial Doppler (c-TCD) and contrast-enhanced transthoracic echocardiography (c-TTE) for right to left shunt (RLS) in patent foramen ovale (PFO) by meta-analysis. Methods: The literature included in the Cochrane Library, PubMed, and Embase were searched by using "contrast-enhanced transcranial Doppler (c-TCD), contrast-enhanced transthoracic echocardiography (c-TTE), patent foramen ovale (PFO), and right to left shunt (RLS)" as the keywords from inception through April 30, 2024. The diagnostic accuracy research quality assessment tool (QUADAS-2) was used to evaluate the quality of the included literature. The combined sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), and Diagnostic odds ratio (DOR) were pooled, and a comprehensive ROC curve analysis was performed. Statistical software StataSE 12.0 and Meta-Disc 1.4 were used for data analysis. Results: A total of 8,536 articles were retrieved, and 9 articles that met all inclusion criteria were included in this meta-analysis. The meta-analysis results show that the combined sensitivity, specificity, PLR, NLR, DOR, and area under the SROC curve of c-TCD for the diagnose of PFO-RLS were 0.91 (95% CI, 0.88-0.93), 0.87 (95% CI: 0.84-0.91), 6.0 (95% CI, 2.78-12.96), 0.10 (95% CI, 0.06-0.18), 91.61 (95% CI, 26.55-316.10), and 0.9681, respectively; the corresponding values of c-TTE were 0.86 (95% CI, 0.84-0.89), 0.88 (95% CI, 0.84-0.91), 5.21 (95% CI, 2.55-10.63), 0.16 (95% CI, 0.09-0.31), 71.43 (95% CI, 22.85-223.23), and 0.9532. The ROC curve shows that c-TCD has slightly higher diagnostic value for PFO than c-TTE, but there is no significant statistical difference (Z = 0.622, p > 0.05). Deek funnel pattern showed no significant publication bias. Conclusion: Both c-TCD and c-TTE have high diagnostic values for PFO-RLS. However, c-TCD has slightly higher sensitivity and lower specificity in diagnosing PFO-RLS compared to c-TTE. Systematic review registration: identifier [CRD42024544169]. Conclusion Both c-TCD and c-TTE have high diagnostic values for PFO-RLS. However, c-TCD has slightly higher sensitivity and lower specificity in diagnosing PFO-RLS compared to c-TTE.