Importance of saline contrast transthoracic echocardiography for evaluating large right-to-left shunt in patent foramen ovale associated with cryptogenic stroke

Yoichi Takaya,Hiroshi Ito,Takashi Miki,Teiji Akagi,Koji Nakagawa,Rie Nakayama,Fumi Yokohama,Norihisa Toh

doi:10.1007/s10554-021-02418-6

Yoichi Takaya, Hiroshi Ito + Show 6 more

Open Access

https://doi.org/10.1007/s10554-021-02418-6

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Abstract

Transcatheter closure of patent foramen ovale (PFO) is an effective therapy for preventing recurrent stroke in very specific patient cohorts, such as cryptogenic stroke (CS). The identification of high-risk PFO, which is more likely to be linked to CS, is essential. This study aimed to assess the accuracy of saline contrast transthoracic echocardiography (TTE) for evaluating large right-to-left (RL) shunt. We enrolled 119 patients with or without CS who were confirmed to have PFO by transesophageal echocardiography (TEE) or catheterization. The severity of RL shunt evaluated by TTE and TEE was classified as follows: small (< 10 microbubbles), moderate (10–20 microbubbles), and large (> 20 microbubbles). With TTE, large RL shunt was observed in 94 (79%) of 119 patients, including 66 of 74 with CS and 28 of 45 without CS. With TEE, large RL shunt was observed in 33 (28 %) patients, including 26 with CS and 7 without CS. TTE showed large RL shunt more frequently than TEE (p < 0.01). Large RL shunt evaluated by TTE had a sensitivity of 89 % and an accuracy of 70 % for the association with CS, whereas large RL shunt evaluated by TEE had a sensitivity of 35% and an accuracy of 56 %. Accuracy was significantly greater in TTE than in TEE (p = 0.02). In conclusion, TTE identified large RL shunt associated with CS with higher sensitivity and accuracy compared to TEE. Our findings suggest that the decision for device closure should be made based on the severity of RL shunt by TTE.

Highlights

Patent foramen ovale (PFO) is linked with various diseases, including cryptogenic stroke (CS) [1,2,3,4,5,6]
The major findings of the present study were: (1) saline contrast transthoracic echocardiography (TTE) showed large RL shunt more frequently than transesophageal echocardiography (TEE), and (2) large RL shunt evaluated by TTE had greater sensitivity and accuracy for the association with CS compared to that evaluated by TEE, and large RL shunt evaluated by TEE had greater specificity compared to that evaluated by TTE
Since randomized trials, such as the RESPECT, REDUCE, and CLOSE trials, have demonstrated the benefits of transcatheter closure for the reduction of stroke [7,8,9], transcatheter closure of PFO is expected to increase as a therapeutic option

Summary

Introduction

Patent foramen ovale (PFO) is linked with various diseases, including cryptogenic stroke (CS) [1,2,3,4,5,6]. Large right-to-left (RL) shunt is effective to stratify PFO for an increased risk of CS. Saline contrast transesophageal echocardiography (TEE) remains the standard reference for assessing the severity of RL shunt [11, 12]. TEE often has the difficulty in accurately evaluating large RL shunt due to an insufficient Valsalva maneuver. Saline contrast transthoracic echocardiography (TTE) has been reported to be useful for PFO detection with a high sensitivity and specificity [13]. TTE does not require the fasting state and can obtain an adequate Valsalva maneuver. TTE may identify more large RL shunt as compared to TEE given the differences in loading conditions, such as Valsalva maneuver and hemodynamics. TTE may be a better imaging modality for decision making with regard to device closure

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