Inferior Vena Cava Compression as a Novel Maneuver to Detect Patent Foramen Ovale: A Transesophageal Echocardiographic Study

Cryptogenic stroke and patent foramen ovale: endeavoring for clarity

This review aims to summarize current knowledge and highlight recent findings on the association between cryptogenic stroke (CS) and patent foramen ovale (PFO). By presenting sometimes conflicting data, the review underscores the necessity for further research to clarify the complex mechanisms behind PFO-related CS and optimize its management. Results from research identifies specific conditions and scores, such as the risk of paradoxical embolism (RoPE) score, that help assess the likelihood of PFO-related cryptogenic stroke and guide treatment decisions. PFO closure has demonstrated substantial benefits in select cases, especially those with high-risk PFO features, though complications such as atrial fibrillation were frequently documented. Biomarker measurements, such as reduced total homocysteine (tHcy) level after PFO closure or high D-dimer levels indicating a higher risk of stroke recurrence, represent newer areas of study with a promising future in medical practice. Cryptogenic stroke (CS) remains a diagnostic challenge. This article reviews the current understanding of PFO-related CS, focusing on the interplay of concomitant pathological conditions, PFO closure, stroke recurrence, and some of the related biomarkers.

Anatomical Significance of the Patent Foramen Ovale by Real-Time 3D TEE in Cryptogenic Stroke and Migraine

BACKGROUND

The transesophageal echocardiogram (TEE) is the standard imaging modality for confirming the presence or absence of patent foramen ovale. PFO is a flap valve depending on the pressure change between the left and right atrium, which can help determine whether to open. 3D-TEE was shown to optimize the visualization of PFO. There is a causal association between PFO and unexplained stroke. It seems that 3D-TEE can present a high-risk PFO morphological feature, which seems to show more than just being easier to open.

METHODS

In total, 134 consecutive patients with cryptogenic stroke or migraine who had suspected PFO and underwent c-TCD, TTE, and c-TEE were included in this study. TEE confirmed the PFO. The right-to-left shunt (RLS) grade of PFO at rest and abdominal compression Valsalva maneuver was detected by c-TEE.

RESULTS

The long diameter of FO (1.74 ± 0.3 vs. 1.60 ± 0.4, p = 0.039), the short diameter of FO (1.12 ± 0.3 vs. 1.00 ± 0.3, p = 0.036), perimeter of FO (4.62 ± 0.7 vs. 4.22 ± 1.0, p = 0.026), and area (1.80 ± 0.8 vs. 1.35 ± 0.8, p = 0.05) of the FO were significantly larger in the larger RLS group. In group of CS, a larger proportion of Eustachian valve or a Chiari's network (14.3% vs. 3.5%, p = 0.036), a larger proportion of in the left funnelform (55.1% vs. 16.3%, p < 0.001), a longer length of the PFO tunnel (13.4 ± 4.4 vs. 7.8 ± 2.5, p < 0.001), a lower IVC-PFO angle (16.4 ± 3.4 vs. 20.3 ± 7.7, p = 0.001), a higher proportion of LA multiple exits of the tunnel (46.9% vs. 14.3%, p < 0.001). Multivariate regression analysis showed that male gender (HR: 4.026, 95% CI: 0.883-18.361, p = 0.072), age (HR: 1.076, 95% CI: 1.002-1.155, p = 0.045), the left funnelform (HR: 7.299, 95% CI: 1.585-33.618, p = 0.011), a longer length of the PFO tunnel (HR: 1.843, 95% CI: 1.404-2.418, p < 0.001) and multiple exits of the tunnel of LA (HR: 8.544, 95% CI: 1.595-45.754, p = 0.012) increased the risk of cerebral infarction. The cut-off value calculated by ROC for the diagnosis of high-risk PFO was that the length of the PFO tunnel was 12 mm and the left funnelform combined with multiple exits of the left atrial (sensitivity was 92%, specificity was 90%). The area under the curve of the combined index versus PoPE score (0.932 vs. 0.736) relative to the RoPE score was statistically significant.

CONCLUSIONS

TEE has shown outstanding advantages in displaying the specific morphological characteristics of PFO. The left funnelform, a longer length of the PFO tunnel, and multiple exits of the tunnel of LA are associated with an increasing risk of CS in anatomical PFO respect.

Visualized Embolization of Inferior Vena Cava Thrombus During the Abdominal Compression Maneuver to Evaluate for a Patent Foramen Ovale

•IVC compression is an alternative to Valsalva to confirm the presence of a PFO. •A drawback of this method is reduced IVC compression in obese patients. •Use with caution in patients with low cardiac output and gastrointestinal diseases. •No complications while performing this maneuver have been reported. •We report visualized thrombus in the RA during the IVC compression maneuver.

Calf muscle pump tensing as a novel maneuver to improve the diagnostic performance of detecting patent foramen ovale during transesophageal echocardiography

Objective

The Valsalva maneuver is the most sensitive provocative maneuver for patent foramen ovale detection. However, nearly half of patients are unable to perform the Valsalva maneuver well. The aim of this study was to investigate the mechanism of action of calf muscle pump tensing (TENSE) as a novel patent foramen ovale (PFO) provocative maneuver and to evaluate the diagnostic value for PFO and the effect on right-to-left shunt volume compared with the Valsalva maneuver.

Methods

This study prospectively investigated 171 patients who were highly suspected to have PFO clinically. Five patients with atrial septal defects newly diagnosed on transesophageal echocardiography (TEE) were excluded. 166 patients were injected with agitated saline under three provocative maneuvers: Valsalva maneuver, TENSE, and Valsalva + TENSE combined maneuver. The patients were divided into the effective Valsalva group (n = 93) and ineffective Valsalva group (n = 73) according to whether they could perform an effective Valsalva maneuver. TENSE consisted of the straightening of both lower limbs, and when the right atrium was filled with microbubbles, the patient performed instantaneous ankle dorsiflexion movements while maintaining dorsiflexion for 3-5 s.

Results

Overall, the PFO detection rate of the Valsalva + TENSE combined maneuver (78 [50.1%]) was significantly higher than that of the Valsalva maneuver (51 [30.7%]) and TENSE maneuver (57 [34.3%]) (P < 0.001). In the patients who were able to perform an effective Valsalva maneuver, the PFO detection rate by TENSE was not significantly different from that by the Valsalva maneuver (Valsalva 37/93 [39.8%] vs. TENSE 31/93 [33.3%], P > 0.05), while for the patients who performed an ineffective Valsalva maneuver, the PFO detection rate by the TENSE maneuver was higher than that by the Valsalva maneuver (TENSE 26/73 [35.6%] vs. Valsalva14/73[19.2%], P = 0.017).

Conclusion

TENSE is a simple and effective provocative maneuver in the diagnosis of PFO using TEE and can assist the Valsalva maneuver. For patients who cannot perform an effective Valsalva maneuver, TENSE can be an alternative to the Valsalva maneuver to some extent.

Pitfalls of Using Imaging Technique in the Presence of Eustachian Valve or Chiari Network: Effects on Right-to-Left Shunt and Related Influencing Factors

When patent foramen ovale (PFO) combines with the prominent Eustachian valve or Chiari network (EV/CN), contrast transthoracic echocardiography (cTTE) may miss the diagnosis of PFO. We sought to determine the characteristics of right-to-left shunt (RLS) in PFO patients with prominent EV/CN on cTTE and identify the causal factors of missed diagnosis. We consecutively enrolled 98 patients who suffered from PFO-related stroke and with prominent EV/CN. All patients were divided into the delayed and non-delayed groups according to the characteristics of RLS on cTTE. The characteristics of RLS were compared with those of 42 intrapulmonary shunt patients. The anatomical characteristics of PFO and EV/CN were analyzed in the 98 PFO patients. Upon cTTE, significantly delayed occurrence and longer duration of the RLS in the delayed group were found both at rest and during the Valsalva maneuver, similar to the intrapulmonary shunt. Multivariate logistic analysis revealed that the length of EV/CN (>19 mm) and the diameter of PFO at the left atrium aspect (<1.2 mm) were high-risk factors for missed diagnosis. In conclusion, RLS showed delayed emergence and disappearance in some of the PFO patients with prominent EV/CN. The length of EV/CN and the diameter of PFO may have been related to the missed diagnosis of PFO.

Aortic Root Downward Movement as a Novel Method for Identification of an Adequately Performed Valsalva Maneuver to Detect Patent Foramen Ovale during Transesophageal Echocardiograph

The Valsalva maneuver (VM) is the most sensitive auxiliary method for the detection of patent foramen ovale (PFO), but it is difficult to assess whether the maneuver is adequately performed during transesophageal echocardiography (TEE). In this study, we tried to use aortic root downward movement as a novel method for judging whether VM was adequate or not, and to evaluate whether this novel method can increase the sensitivity of detecting PFO. A total of 224 patients with clinically suspected PFO were enrolled in this study. These patients were injected with activated normal saline to detect the right-to-left shunt (RLS), in the following three conditions: contrast-enhanced transthoracic echocardiography under adequate VM (AVM cTTE), contrast-enhanced TEE under non-adequate VM (non-AVM cTEE), and cTEE under adequate VM (AVM cTEE). A novel method in which the aorta root moves downward (movement range ≥16 mm) in the cTEE judged whether AVM was performed. The PFO detection rate and sensitivity of AVM cTEE were better than that of non-AVM cTEE (detection rate: 108 PFOs [48.2%] vs. 86 PFOs [38.4%], p = 0.036; sensitivity: 100% vs. 79.6%). Among AVM cTTE, non-AVM cTEE, and AVM cTEE, the RLS grade evaluation results were inconsistent, with significant differences (p < 0.05). Non-AVM cTEE had RLS underestimation or false negatives. Compared with non-AVM cTEE, AVM cTEE and AVM cTTE had better consistency in evaluating PFO RLS (kappa value = 0.675). Aortic root downward movement could be used as a novel method for judging the effectiveness of VM, which is critical for the detection of PFO in cTEE. Concerning effectiveness and convenience, this method should be promoted during the clinical detection of PFO.

Diagnosis of patent foramen ovale using maximum intensity T-projection imaging

Accurate diagnosis of patent foramen ovale (PFO) and grading of right-to-left shunt severity by the standard method of transthoracic or transesophageal echocardiography (TEE) with bubble injection is often challenging. We proposed the novel Maximum Intensity T-Projection (MIP) Imaging method as a complementary or alternative approach for simplified diagnosis and grading of PFO. MIP Imaging represents the superimposition of all frames of an echocardiographic video onto one image. Thus, all bubbles passing from right to left atrium are represented in this single image. Diagnosis and quantification of PFO by MIP Images were compared to those obtained by standard echocardiographic methods, using the same echocardiography video loops. We applied the MIP Imaging approach to 122 echo examinations (75% of them TEE studies), performed to rule out PFOs. The average time needed to manually analyze video loops taken during bubble injection was 102 ± 52 s vs. less than 1 s using the MIP Imaging method. There was good concordance between the conventional echo method and MIP Imaging in the diagnosis and quantification of PFOs. MIP Imaging for diagnosis and quantification of PFOs was much less time consuming than the classical method and at least as accurate as the classical method. Thus MIP Imaging may be used initially as an adjunct method for PFO diagnosis and quantification and may eventually replace the classical method.

Agitated Saline Contrast Echocardiography in the Identification of Intra- and Extracardiac Shunts: Connecting the Dots

Agitated saline contrast studies are an essential component of contemporary echocardiography. Agitated saline contrast plays a critical role in the elucidation of intracardiac versus intrapulmonary shunting and can have major therapeutic implications, particularly in light of the evolution of percutaneous treatment options for atrial septal defects or a patent foramen ovale. Despite their perceived simplicity, however, there are numerous pitfalls of these investigations that can occur during their performance and interpretation. As such, the authors review the "bubble study" in identifying intracardiac and extracardiac shunts, including the history of its development, the physics and physiology of contrast enhancement, how to optimally perform and interpret an agitated saline contrast study, and its safety in unique populations.

The Presence of Patent Foramen Ovale in the Superior Type of Sinus Venosus Atrial Septal Defect

Background: The superior type of sinus venosus atrial septal defect (SVASD) is a rare form of the atrial septal defect (ASD) in which the upper part of the atrial septum does not exist. The presence of other cardiac anomalies such as anomalous pulmonary venous connections has been reported in this type of congenital heart disease. This study aimed to assess the presence of the patent foramen ovale (PFO) in patients with the superior type of SVASD.

Methods: This retrospective case-control study on 387 patients, consisting of 187 patients with a definite SVASD and 200 patients with problems other than the ASD, was conducted in Rajaie Cardiovascular Medical and Research Center between February 2005 and July 2014. Seven patients with inadequate data were excluded from the analysis. The presence/absence of the PFO was also evaluated in the case and control groups.

Results: The analyses were performed on 182 male and 198 female patients at a mean age of 39.07±14.41 and 51.01±15.80 years in the case and control groups, respectively. The PFO was significantly more frequent in the patients with the superior type of SVASD than in those without the condition (P<0.001). The persistence of the left superior vena cava was seen in 34 out of 180 patients with SVASD and in 1 out of 200 patients without the condition (18.9% vs 0.5%; P<0.001).

Conclusion: This study was the first to highlight the coexistence of the PFO and the superior type of SVASD. Physiological, genetic, or fetal factors may play an important role in the association between the PFO and the SVASD.

Is inferior vena cava compression an alternative for valsalva maneuver in contrast-enhanced transcranial doppler？

OBJECTIVES

To evaluate whether inferior vena cava compression (IVCC) can be an alternative for valsalva maneuver (VM) in contrast-enhanced transcranial doppler (c-TCD).

METHODS

Patients diagnosed with ischemic stroke, transient ischemic attack, and migraine were enrolled in this study. C-TCD was conducted at resting state, after VM and IVCC to detect right to left shunt (RLS). Then, the RLS was compared to examine whether IVCC could be an alternative for VM in c-TCD.

RESULTS

A total of 246 patients were enrolled in this study. Via Wilcoxon signed-rank test of paired data, the detection for RLS of c-TCD conducted after IVCC was superior to at resting state, but inferior to after VM (P ＜ .001, P = .01, respectively); the detection for RLS of c-TCD conducted after IVCC was inferior to after VM for patients with good cooperation of VM, but was superior for patients with poor cooperation of VM (P ＜ .001, P ＜ .001, respectively); the detection for RLS of c-TCD conducted after IVCC and after VM showed no significant difference for patients with good cooperation of VM and without abdominal obesity, or with poor cooperation of VM and with abdominal obesity (P = .201, P = .157, respectively); the detection for RLS of c-TCD conducted after IVCC was superior to at resting state for patients with abdominal obesity (P ＜ .001).

CONCLUSIONS

For patients with poor cooperation of VM, IVCC could be used as an effective supplement to increase the detection of RLS in c-TCD.

Patent Foramen Ovale: Pivotal Role of Transesophageal Echocardiography in the Indications for Closure, Assessment of Varying Anatomies and Post-procedure Follow-up

Patent foramen ovale (PFO) is present in 15%-30% of the general population and has been associated with various pathologic states, including cryptogenic stroke, platypnea-orthodeoxia syndrome, decompression sickness and migraine with auras. Transesophageal echocardiography (TEE) has a major role in the diagnostic evaluation of PFO, as well as in the post-procedural assessment after transcatheter closure. The goals of this article were to synthesize the echocardiographic transesophageal techniques required for accurate PFO diagnosis and careful anatomic assessment of its anatomic variants, to focus TEE indications for device closure as complementary to clinical indications and to assess the role of TEE in the post-procedure follow-up.

Identification of High-Risk Patent Foramen Ovale Associated With Cryptogenic Stroke: Development of a Scoring System

BACKGROUND

Transcatheter closure of patent foramen ovale (PFO) has become an effective therapeutic strategy for cryptogenic stroke (CS). The identification of high-risk PFO is essential, but the data are limited. This study aimed to clarify the factors related to CS and to develop a score for high-risk PFO.

METHODS

We retrospectively analyzed 57 patients with prior CS and 50 without CS who were scheduled for transcatheter closure. PFO characteristics were evaluated by transesophageal echocardiography. Based on factors related to CS, we estimated the risk score.

RESULTS

Patients with CS had a greater frequency of large-size PFO (≥2 mm in height), long-tunnel PFO (≥10 mm in length), atrial septal aneurysm, hypermobile interatrial septum, prominent Eustachian valve or Chiari's network, the large right-to-left shunt at rest and during Valsalva maneuver, and low-angle PFO (≤10° of PFO angle from inferior vena cava), compared with patients without CS. Multivariate analysis showed that long-tunnel PFO, the presence of hypermobile interatrial septum, the presence of prominent Eustachian valve or Chiari's network, the large right-to-left shunt during Valsalva maneuver, and low-angle PFO were independently related to CS. When the score was estimated based on 1 point for each factor, the proportion of CS was markedly elevated with a score of ≥2 points. The probability of CS was markedly different between scores of ≤1 or ≥2 points.

CONCLUSIONS

PFO risk can be assessed with a score based on high-risk features. The presence of two or more high-risk PFO features is associated with CS.

Provocative maneuvers to improve patent foramen ovale detection: A brief review of the literature

Patent foramen ovale (PFO) is the most common type of inter-atrial shunt, with prevalence as high as 30%. Detection of PFO has implications in patients with stroke, peripheral embolism, decompression illness, and other conditions. Transesophageal echo (TEE) with saline contrast injection is the current standard for PFO detection, but even with TEE, PFOs are sometimes missed. With advances in percutaneous PFO closure therapies and proven long-term benefit of closure, accurate PFO detection takes on cardinal importance. Various provocative maneuvers to enhance PFO detection are in clinical use and have been studied. The Valsalva maneuver has long-held position as the ideal provocation to unmask PFO, but other maneuvers such as cough, sniff, Müller's, and more have gained relevance. In this article, we will examine various maneuvers and discuss their utility in PFO detection.