Eliminating right-to-left shunt with patent foramen ovale closure: not as simple as it seems

The Value of Contrast-Enhanced Transesophageal Echocardiography in the Detection of Cardiac Right-to-Left Shunt Related with Cryptogenic Stroke and Migraine

Purpose

To analyze the characteristics of right-to-left shunt (RLS) in patients with cryptogenic stroke and migraine by contrast-enhanced transesophageal echocardiography (c-TEE).

Methods

The study population consisted of 330 patients with cryptogenic stroke and 330 patients with migraine who suspected PFO. All of them received c-TEE examination successfully. In terms of c-TEE analyses, RLS could be diagnosed when microbubbles were visualized in the transition from the right atrium to the left atrium. For semiquantitative analysis, a small amount of RLS was grade 1, indicating 1-10 microvesicles per frame could be seen in the left atrium, a moderate amount of RLS was grade 2, indicating 11-30 microvesicles per frame could be seen in the left atrium, and a large amount of RLS was grade 3, indicating more than 30 microvesicles per frame, or the left atrium is filled with microvesicles.

Results

A total of 660 patients were analyzed in the study. PFO-RLS was detected in 348 (348/660, 52.7%) cases by TEE, while in 392 (392/660, 59.3%) cases by c-TEE. Simultaneously, P-RLS was detected in 239 (239/660, 36.2%) cases by c-TEE. Among 330 patients with cryptogenic stroke, PFO-RLS was detected in 198 cases; according to the c-TTE method (198/330, 60.0%), concurrently, 83 participants suffered from PFO-RLS and P-RSL (83/330, 25.1%), including 1 case with PFO and pulmonary arteriovenous fistula. Among 330 patients with migraine, PFO-RLS was detected in 194 cases; according to the c-TTE method (194/330, 58.7%), specifically, 90 participants suffered from PFO-RLS and P-RSL (90/330, 27.2%). There was no statistical significance between the two groups. P-RLS singly was detected in 28 cases with cryptogenic stroke, while in 38 cases with migraine, excluding from pulmonary arteriovenous fistula by CTA examination. In addition, semiquantitative results on c-TTE grading of RLS were compared between the two groups: grade 1 RLS in the migraine group (144/322) was significantly higher than that in the cryptogenic stroke group (71/309) (P < 0.05). Grade 3 RLS in the cryptogenic stroke group (113/309) was significantly higher than that in the migraine group (67/322) (P < 0.05). For grade 2 RLS, there was no statistical difference between the two groups (P = 0.12).

Conclusions

c-TEE can increase the positive rate of PFO diagnosis compared with TEE color Doppler. There is no significant difference in the incidence of PFO-PLS and P-RLS between the cryptogenic stroke group and the migraine group. The grades 2-3 RLS are mainly detected in the cryptogenic stroke group, while grades 1-2 RLS are mostly detected in the migraine group.

Contrast-enhanced transthoracic echocardiography applied in evaluation of pulmonary right-to-left shunt: A preliminary study

OBJECTIVE

To investigate the detection rate of patent foramen ovale-right to left shunt (PFO-RLS) and/or pulmonary-right to left shunt (P-RLS) via contrast-enhanced transthoracic echocardiography (c-TTE) in healthy participants, patients suffering from cryptogenic stroke and migraine with aura.

METHODS

Initially, 20 healthy volunteers, 21 cases with cryptogenic stroke, and 18 cases with migraine aura were randomly selected, and all of them received c-TTE and transesophageal echocardiography (TEE) examinations. First of all, 0.9% sodium chloride solution was rapidly injected into upper extremiry vein, when these volunteers and patients were at rest or following a Valsalva maneuver with 40 mm Hg pressure exerted against a manometer. Secondly, c-TTE detection was carried out in order to distinguish PFO-RLS and P-RLS and make semi-quantitative classification of RLS from many different sources, according to the occurrence and duration time of microvesicles in left atrial after the developing of left atrium. In terms of c-TTE analyses, RLS could be diagnosed when micro bubbles were visualized in transition from the right atrium to the left atrium. Particularly, a small amounts of RLS was 1 level, indicating 1-10 microvesicles per frame could be seen in left atrium, moderate amounts of RLS was 2 level, indicating 11-30 microvesicles per frame could be seen in left atrium, and a large amounts of RLS was 3 level, indicating more than 30 microvesicles per frame, or the left atrium is filled with micro vesicles.

RESULTS

A total of 20 healthy adult volunteers were identified into this research. RLS was detected in 7 cases, according to c-TTE method (7/20, 35%). In detail, 3 participants suffered from PFO-RLS and P-RSL (3/20, 15%) simultaneously, 5 cases suffered from PFO-RLS (5/20, 25%), and 5 cases suffered from P-RLS (5/20, 25%). Among 21 patients with cryptogenic stroke, RLS was detected in 14 cases, according to cTTE method (14/20, 67%), and then compared with healthy participants group, the difference between them was significant (χ² = 4.11, P = 0.04). Specifically, 2 participants suffered from PFO-RLS and P-RSL (2/21, 9.5%), 11 cases suffered from PFO-RLS (11/21, 52.4%), and 5 cases suffered from P-RLS (5/21, 23.8%). Among 21 patients suffering from migraine with aura, RLS was detected in 13 cases, according to c-TTE method (13/18, 72%), and then compared with healthy participants group, the difference of detection rate between them was significant (χ² = 5.2, P = 0.02). In detail, 3 participants suffered from PFO-RLS and P-RSL (3/18, 16.7%), 8 cases suffered from PFO-RLS (8/18, 44.4%), and 8 cases suffered from P-RLS (8/18, 44.4%). In addition, the grading of PFO-RLS in patients suffering from cryptogenic stroke and migraine with aura was mostly grade 2-grade 3. On the contrary, the grading of PFO-RLS in healthy adult volunteers was mostly grade 1-2. Besides, the semi-quantitative grading of P-RLS in each group was mostly grade 1 to grade 2, and difference between healthy volunteer group and cryptogenic stroke group was significant (Z = -2.77, P = 0.006).

CONCLUSION

P-RLS with lower semiquantitative grade is common in healthy individuals, patients with cryptogenic stroke and migraine aura. And P-RLS can be considered as a significant influencing factor in the pathogenesis of migraine with aura.

Patent foramen ovale and cryptogenic stroke: from studies to clinical practice: Position paper of the Italian Chapter, International Society Cardiovascular Ultrasound

BACKGROUND

Over the last two decades the interest on patent foramen ovale (PFO) as a cause of cardioembolism in cryptogenic stroke has tremendously increased, thanks to the availability of better techniques to diagnose cardiac right-to-left shunt by ultrasounds and of percutaneous means of PFO treatment with interventional techniques. Many studies have been published that have attempted to define diagnostic methodology, prognosis, and optimal treatment (pharmacological or percutaneous closure) of PFO patients with cryptogenic stroke. Unfortunately, even today, definitive evidence is still lacking, and clinical management is not consistent among cardiologists.

AIMS

This review aims to evaluate the role of PFO in cryptogenic stroke, the diagnostic accuracy of transcranial Doppler, contrast transthoracic and transesophageal echocardiography in the diagnosis of left-fright shunt and PFO; and discuss the indications to medical treatment and percutaneous closure of PFO.

METHODS

All studies published in the literature on PFO and cryptogenic stroke are considered and discussed.

RESULTS

We define an appropriate diagnostic and clinical management of PFO patients with cryptogenic stroke.

CONCLUSION

After many years of interest on PFO and many concluded studies, there are still no definitive data. However, we are on good track for an appropriate management of PFO patients and cryptogenic stroke.