# Integrated assessment of contrast-enhanced TCD and TTE for noninvasive detection of patent foramen ovale under resting and Valsalva conditions

## TL;DR

This study compares two noninvasive methods for detecting a heart condition called patent foramen ovale and finds that combining them improves accuracy.

## Contribution

The study introduces an integrated diagnostic model combining c-TCD and c-TTE to improve PFO detection accuracy.

## Key findings

- The Valsalva maneuver significantly increased detection rates of right-to-left shunts in both c-TCD and c-TTE.
- Combining c-TCD and c-TTE achieved 100% sensitivity and negative predictive value in the TEE subgroup.
- The integrated model showed strong clinical benefit and could reduce the need for invasive TEE procedures.

## Abstract

To compare the diagnostic performance of contrast-enhanced transcranial Doppler (c-TCD) and contrast-enhanced transthoracic echocardiography (c-TTE) under resting and Valsalva conditions for detecting patent foramen ovale (PFO), and to evaluate the clinical utility of an integrated diagnostic model combining both modalities.

In this retrospective study, a total of 146 patients with suspected PFO underwent both c-TCD and c-TTE at rest and during the Valsalva maneuver. Among them, 40 patients also received contrast-enhanced transesophageal echocardiography (c-TEE), which served as the reference standard. Detection rates, shunt grading, and inter-modality agreement were analyzed. A logistic regression model integrating c-TCD and c-TTE findings was developed and assessed using receiver operating characteristic (ROC) curves and decision curve analysis (DCA).

The Valsalva maneuver significantly increased the detection rates of right-to-left shunt (c-TCD: from 41.4% to 76.7%; c-TTE: from 45.2% to 80.1%) and the proportion of Grade 3 shunts (P < 0.0001). At rest, c-TCD detected more high-grade shunts than c-TTE (P = 0.030), supporting its use as a sensitive initial screening tool. Inter-modality agreement improved markedly during Valsalva (weighted Kappa = 0.782). The combined model achieved 100% sensitivity and negative predictive value in the TEE subgroup, with an area under the ROC curve of 0.97 and no false negatives. DCA confirmed the superior net clinical benefit of the integrated approach across a broad range of decision thresholds.

Valsalva maneuver significantly enhances the diagnostic yield of both c-TCD and c-TTE. While c-TCD may serve as an effective first-line screening tool, its combination with c-TTE ensures improved diagnostic accuracy and clinical decision-making value. The integrated model demonstrates strong potential for clinical implementation as a noninvasive, efficient strategy to reduce unnecessary c-TEE procedures.