Bicaval View Research Articles

Simultaneous release of interdigitating atrial septal defect and patent foramen ovale Amplatzer devices

In the absence of an alternative cause of breathlessness, a 73-year-old patient with an atrial septal defect and right volume overload on echocardiography was referred for transcatheter device closure under general anesthesia. After balloon sizing under fluoroscopy, a 22 mm Amplatzer (AGA Medical Corporation, USA) septal occluder device was partially deployed. However, transesophageal echocardiography revealed a large patent foramen ovale (PFO) (Figure 1A). Figure 1 Transesophageal, bicaval echo view of the interatrial septum. A Central ostium secundum atrial septal defect (ASD) and patent foramen ovale (PFO). B The ASD device is deployed but not released. The rim of the larger left atrial disc fails to cover neck ... Multiple defects in the atrial septum may be occluded by one large device (1), but the 22 mm device with a 7 mm left atrial disc rim failed to close the neck of the PFO (Figure 1B). Agitated saline contrast injection via the inferior vena cava revealed dense puffs of contrast moving across the PFO (Figure 1C). For dual ASD device closures, deployment of the smallest device followed by the larger is advocated (2). Our need for a large 34 mm Amplatzer PFO occluder posed a technical challenge, addressed in Figure 2. Figure 2 A Left atrial (LA) disc of atrial septal defect (ASD) device deployed with gentle traction into the defect within centre of fossa ovalis. The LA disc of the Amplatzer (AGA Medical Corporation, USA) patent foramen ovale (PFO) occluder overlapped the ASD ...

Left Ventricular to Right Atrial Communication (Gerbode-type Defect) After Mitral Valve Replacement

A 51-year-old woman with severe rheumatic mitral stenosis underwent mitral valve replacement. One week later, she was admitted with abdominal pain and lower extremities edema. On physical examination, her blood pressure was 120/60 mm Hg and holosystolic murmur (3/6) was heard at the left sternal border. Transesophageal echocardiography was done and revealed a shunt flow from the left ventricle to the right atrium in the 4-chamber and bicaval views. With careful examination of the interventricular septum, a small defect was seen in the membranous interventricular septum, which connects the left ventricle to the right atrium. The patient underwent surgical operation with diagnosis of iatrogenic left ventricular to right atrial communication (Gerbode-type defect). Intraoperative finding confirmed the preoperative diagnosis.

Absent Right Superior Vena Cava and Persistent Left Superior Vena Cava: The Perioperative Implications

A 22-yr-old female patient was admitted for repair of tetralogy of Fallot. Preoperative transthoracic echocardiography revealed large subaortic ventricular septal defect, 50% aortic over-ride, severe valvular and subvalvular pulmonary stenosis, persistent left superior vena cava (PLSVC), and a large coronary sinus (CS). After anesthetic induction, central venous cannulation of the right internal jugular vein was attempted with a 20-guage cannula using Seldinger’s technique. Despite free flow through the cannula, the guidewire could not be advanced beyond 8 cm; therefore, a pediatric (8 cm, 5.5F) triple-lumen catheter was inserted. Intraoperative transesophageal echocardiography (TEE) imaging of the midesophageal (ME) bicaval view with the transducer steered through 90–120° suggested absence of the right superior vena cava (RTSVC) (Figs. 1a and b) (please see video loops available at www.anesthesia-analgesia.com). However, a large PLSVC and CS (Fig. 2) (see video loop) were seen midway between the ME four-chamber and a deep four-chamber view; the probe was slightly rotated counterclockwise. The absent RTSVC was evident on opening the pericardium. After aortic and inferior vena cava cannulation and institution of cardiopulmonary bypass a separate cannula was inserted extrapericardially in the PLSVC. The surgical repair and postoperative course were uneventful. An absent RTSVC is always associated with a PLSVC, with a reported incidence of 0.1% (1). It should be suspected when the chest radiograph does not show its characteristic shadow, particularly with an extra shadow (PLSVC) above the aortic knob (1). On TEE examination, the RTSVC is usually well visualized in the ME bicaval view. Agitated saline administered centrally appears as contrast in the RTSVC and right atrium (RA). With an absent RTSVC, contrast appears in the RA via the CS and can be viewed just below the ME four-chamber view and in bicaval view; however, if the CS is unroofed [absence of common wall between CS and left atrium (LA)], the contrast appears in both the LA and RA. A PLSVC descends along the left paramediastinal structures, anterior to the aortic arch and left pulmonary artery. It then passes inferiorly; in its course receives its tributary the hemiazygos vein, and then descends medially between the left pulmonary veins and left atrial appendage joining the CS in the atrioventricular groove (Fig. 3) causing an enlarged CS. Enlargement of the CS ( 1 cm) may indicate right atrial hypertension, an anomalous systemic venous channel draining through it (e.g., connection of PLSVC, hepatic veins, inferior vena cava), fistulous communication with coronary arteries and total or partial anomalous pulmonary venous connection. A PLSVC can be seen in ME views in the vicinity of the left atrial appendage and left upper pulmonary vein with the probe rotated counterclockwise, and can be traced to its entry into the CS. Occasionally, a PLSVC can be misdiagnosed as descending thoracic aorta, however, it can be differentiated from the descending thoracic aorta by pulse-wave Doppler assessment that shows continuous flow in the PLSVC and pulsatile flow in the descending thoracic aorta. The diagnosis of PLSVC is classically made by injecting contrast into the left-sided brachiocephalic veins and demonstrating contrast appearance in the PLSVC, CS, and RA (in that sequence). In 10% of patients, a PLSVC may drain into the LA either directly or via an unroofed CS; in such a situation, contrast first appears in the LA. Because of the PLSVC draining into the LA (right to left shunt) the arterial blood gas analysis or pulse oximetry will show desaturation. Although, this finding will not help evaluation of cyanotic patients, it can create a diagnostic and management dilemma in patients with acyanotic lesions. This article has supplementary material on the Web site: www.anesthesia-analgesia.org.

Transoesophageal echocardiography and central line insertion

We investigated the potential utility of transoesophageal echocardiography (TOE) in facilitating central venous catheter (CVC) insertion in patients undergoing cardiac surgery. Thirty five patients undergoing elective cardiac surgery and CVC insertion were prospectively included in the observational, single-centre clinical investigation. Following induction of general anaesthesia and tracheal intubation, the TOE probe was inserted and the bicaval view obtained prior to CVC insertion (site at discretion of the anaesthesiologist). Prospectively collected data included site and sequence of CVC insertion attempts, information regarding ease of guidewire insertion, whether or not guidewire was visualized via TOE, and other pertinent information. In 1 patient, the TOE bicaval view could not be readily obtained because of right atrial (RA) distortion. In 31 patients, the TOE bicaval view was obtained and CVC access was successful at the site of first choice (guidewire visualized in all). Three patients had noteworthy CVC insertions. In one, CVC insertion was difficult despite visualization ofguidewire in the RA. In another, multiple guidewire insertions met with substantial resistance and without visualization of guidewire in the RA. One patient was found to have an unanticipated large mobile superior vena cava thrombus that extended into the RA, which changed clinical management by prompting initial CVC insertion into the femoral vein (potentially avoiding morbidity associated with thrombus dislodgement). Our prospective observational clinical study indicates that routine use of TOE during CVC insertion may help avoid potential complications associated with this intervention. If both CVC insertion and TOE are going to be used in the same patient, the benefits of TOE should be maximized by routine visualization of the bicaval view during guidewire insertion.

Inferior Vena Cava Diameter and Central Venous Pressure Correlation During Cardiac Surgery

The purpose of this study was to determine whether a relationship exists between the inferior vena cava diameter (IVCD) or the superior vena cava diameter (SVCD) measured at the point of entry into the right atrium using transesophageal echocardiography (TEE) and the central venous pressure (CVP) under different experimental conditions. Prospective study. University hospital, single institution. Seventy patients undergoing elective cardiac surgery. CVP, IVCD, and SVCD were measured in a 2-dimensional, long-axis midesophageal bicaval view at end-diastole with electrocardiographic synchronization. Data were recorded during suspended ventilation, before and after leg elevation, and at different levels of positive end-expiratory pressure (0, 5, and 10 cmH(2)O). The relationship between IVCD and CVP had 2 portions: A first (CVP <or=11 mmHg) in which the IVCD showed a strong correlation with the CVP (R = 0.801, p < 0.001; CVP = 2.009 + [0.312 * IVCD]) and a second (CVP >11 mmHg) in which the correlation was poor (R = 0.272, p = 0.065). No correlation between SVCD and CVP was observed. A strong correlation between TEE-derived IVCD measured at the point of entry into the right atrium and CVP was observed in cardiac surgical patients when CVP was <or=11 mmHg.

An Unusual Transesophageal Echocardiographic Finding After Gore-Tex Patch Closure of an Atrial Septal Defect

A 25-YEAR-OLD woman with ostium secundum atrial septal defect (ASD) was scheduled for patch closure of the defect. Routine transesophageal echocardiography (TEE) in the operating room showed a 3.5-cm ostium secundum ASD with a left-to-right shunt. She underwent a Gore-Tex (expanded polytetrafluoroethylene [ePTFE]; WL Gore & Associates, Inc, Flagstaff, AZ) patch closure of the ASD under standard cardiopulmonary bypass (CPB). TEE was performed after termination of CPB, and a midesophageal 4-chamber view showed the hyperechogenic Gore-Tex patch along the interatrial septum and the cardiac chambers appeared normal (Fig 1). During routine drug administration via a central venous catheter placed in the internal jugular vein, it was noticed that the patch was casting a sharply delineated “shadow” in the right atrium. Therefore, agitated saline contrast was injected. The contrast appeared in the right ventricle, but the right atrium appeared anechoic and the Gore-Tex patch was seen to cast a sharply delineated shadow that almost completely overlapped the rightatrium (Fig 2). Color Doppler images also showed a sharply delineated shadow that overlapped the right atrium and absence of color in the right atrium. The patient was electively ventilated overnight in view of severe pulmonary artery hypertension. During a TEE examination performed on the next day, it was observed that the shadow had disappeared and the Gore-Tex patch had lost its hyperechogenicity. The saline contrast was seen to fill the whole right atrium (Fig 3). Why was the shadow observed initially, and what is the reason for its disappearance within a day? Fig 2Transesophageal echocardiography, 4-chamber view after injecting saline contrast in the internal jugular vein clearly shows the acoustic shadow cast by the Gore-Tex patch overlapping the right atrium. View Large Image Figure Viewer Fig 3Transesophageal echocardiography, bicaval view at 108° obtained the next day shows that the patch has lost its echogenicity, the acoustic shadow in the right atrium has disappeared, and the saline contrast is seen filling the right atrium. View Large Image Figure Viewer

Transesophageal Echocardiography for the Diagnosis and Management of Massive Pulmonary Embolism

A 48-yr-old trauma victim complained of an acute onset of dyspnea and chest pain. Pulmonary embolism was diagnosed by fast spiral computed tomography (CT) requiring emergency surgical embolectomy. After induction of general anesthesia, transesophageal echocardiography (TEE) examination showed enlargement of the right atrium and the right ventricle, bulging of the interatrial and interventricular septum, and right pulmonary artery thrombus (Fig. 1). Further TEE imaging disclosed free-floating thrombi in the right atrium and a thrombus traversing a patent foramen ovale (PFO) (Fig. 2). Continuous right-to-left shunt through the PFO and moderate tricuspid regurgitation was demonstrated with color flow Doppler (please see video loop available at www.anesthesia-analgesia.org). Pulmonary artery systolic pressure was calculated to be 65 mm Hg. After initiation of cardiopulmonary bypass and cardiotomy, 2 thrombi >2 cm in diameter were removed from the right atrium and the foramen ovale was closed. Subsequently, open pulmonary embolectomy was performed and two large thrombi were removed from the left and the right pulmonary arteries. The patient was successfully weaned from cardiopulmonary bypass and had an uneventful postoperative course.Figure 1.: TEE (midesophageal ascending aorta short-axis view) allows visualization of extracardiac and extrapulmonary location such as the superior vena cava (SVC). A thrombus (TH) is seen in the right pulmonary artery (RPA). Ao = aorta.Figure 2.: TEE (mid-esophageal bicaval view) showing two large thrombi (TH1 and TH2) in transit type A in the right atrium (RA), one of which (TH2) is entrapped in a patent foramen ovale. LA = left atrium; RV = right ventricle.Although spiral CT is the diagnostic test of choice for suspected pulmonary embolism, echocardiography can provide complimentary information, including thrombus in transit, found in 4% to 18% of cases, and PFO (1). When present, a PFO is an independent predictor of risk for stroke, major postoperative morbidity, and mortality after thromboembolectomy (2). TEE is also a reliable technique for identifying thromboembolism in extrapulmonary and extracardiac locations, including the vena cava (3). In this case, preoperative CT showed a large central pulmonary embolism extending into the pulmonary arteries, but it did not reveal intracardiac thrombi. Nonetheless, as in this case, TEE is insensitive for the detection of thrombus in the pulmonary artery (3). Regardless, TEE did provide information that led to modification of the surgical strategy, leading to direct vena caval cannulation to allow for extraction of the atrial thrombus and PFO closure.

Diagnostic Dilemma: A Pacemaker Lead Inside the Left Atrium or an Echocardiographic Beam Width Artifact?

A 71-yr-old man with a permanent dual chamber pacemaker (pm), chronic atrial fibrillation with a slow ventricular response and symptomatic mitral regurgitation presented for mitral valve surgery. His intraoperative monitoring included, among others, a pulmonary artery catheter (PAC) and transesophageal echocardiography. The surgical approach was from the right atrium via an atrial septotomy, and the mitral valve was replaced. After separation from cardiopulmonary bypass, a strong reflector accompanied by distal acoustic shadowing was seen inside the left atrium (LA), in the mid-esophageal bicaval view at different degrees of rotation (see video clip at www.anesthesia-analgesia.org.). Migration of the PAC into the LA via the atrial septotomy was excluded, based on the fact that central venous and pulmonary artery pressure waveforms were transduced from the proximal and distal PAC ports, respectively. We considered that one of the permanent pm leads was apparently trapped inside the LA. However, the surgeon was adamant that this had not occurred, and the chest was closed. Further transesophageal echocardiography examination, using similar acoustic windows, failed to reproduce the artifact (Fig. 1). A postoperative portable chest radiograph verified that both permanent pm leads were anchored properly at the right atrium and right ventricular apex.Figure 1.: Modified, mid-esophageal bicaval view after chest closure. A, The left atrium (LA) is at the top of the image. Inside the right atrium (RA), a prominent Eustachian valve is seen to the left, close to the junction with the inferior vena cava (IVC), below the interatrial septum (IAS). One of the pacemaker leads (PM1) is visible. B, With further rotation to 92°, the second pacemaker lead (PM2) is visualized inside the RA.Apart from the main beam, ultrasound transducers emit secondary beams, or side lobes, propagating radially from the center of the main beam (Fig. 2). A returning echo produced by a target located in the side lobes will be displayed as if it originated inside the main beam. The ultrasound energy in the side lobes is considerably weaker than in the main beam; therefore, reflections become apparent only when they do not conflict with real, more intense echoes (1). Examples are an enlarged cardiac chamber, as in the case of a dilated aorta, when the atrial-aortic interface creates a reverberation artifact mimicking a dissection flap, (2) and/or a relatively strong reflector, such as a catheter or a wire (3). To reduce such artifacts, the gain settings should be minimized so that strong reflections from weaker lobes are decreased. If they persist, the echocardiographer may be able to differentiate an artifact from a real structure by imaging the same structure from another acoustic window. An artifact is not likely to be reproduced in multiple echocardiographic planes.Figure 2.: Main and side lobes of the ultrasound beam produced by a phased array transducer. The shadowed cylinder represents the main beam, and the surrounding truncated cone and arrows the side lobes.Shadowing is the absence of echoes behind a highly reflective target, such as mechanical devices (catheters, prostheses) or heavily calcified native structures. When shadowing occurs, an alternate acoustic window is required to view the objects or areas of interest (3). Closure of the atrial septotomy might have altered the relative position between the interatrial septum and the pm lead. As a result, part of the latter (a strong reflector), was reflected by the side lobe, off the center of the ultrasound beam. Approximation of the sternum and the influence of the ventilated lungs may have affected the size of the LA, possibly realigning the pm lead with the main beam of the ultrasound, thus “returning” the image in its true anatomic location, inside the right atrium.

A large Eustachian valve is a confounder of contrast but not of color Doppler transesophageal echocardiography in detecting a right-to-left shunt across a patent foramen ovale

Background Transesophageal contrast echocardiography (cTEE) is considered to be the method of choice for diagnosing patent foramen ovale (PFO), but its diagnostic accuracy compared with color Doppler guided TEE in the presence of an Eustachian valve (EV) has not been evaluated. The main aim of this study was to assess the diagnostic accuracy for PFO diagnosis of color Doppler TEE at low pulse repetition frequency. Methods We ascertained the presence of PFO and EV using cTEE and transthoracic contrast echocardiography (cTTE) in 292 consecutive patients (age 42 ± 12 years) with cryptogenic stroke. A diagnosis of PFO was based on the observation of right-to-left shunting of contrast bubbles or by color Doppler with pulse repetition frequency of 20–30 cm/s. An EV with a diameter of > 1.5 cm in the bicaval view was considered large. Results Overall 204 patients (70%) had evidence of a right-to-left shunt by either contrast echo method. Shunting was demonstrated more frequently by color Doppler than by cTEE, either spontaneously (133 vs. 92; p = 0.01) or during provocative maneuvers (166 vs. 184; p = 0.01). The sensitivity of color Doppler was significantly higher than that of cTEE (90% vs. 81%; p = 0.01). A large EV was found in 37 patients, 31 (84%) of whom had a PFO. The presence of a large EV did not significantly influence the sensitivity of color Doppler for detecting shunting through a PFO, but the sensitivity of cTTE and cTEE was significantly reduced (from 88% to 42%, p < 0.001). Conclusions Color Doppler TEE is more accurate than traditional cTEE for PFO diagnosis and is not negatively influenced by the presence of an EV, provided that a low pulse repetition frequency is used.

Diagnosis of patent foramen ovale with multiplane transesophageal echocardiography in adult cardiac surgical patients

Objective: To evaluate multiplane transesophageal echocardiography (TEE) for detection of patent foramen ovale (PFO) and to compare multiplane TEE with visual inspection (VI) for PFO detection. Design: A prospective observational study. Setting: University hospital (single institution). Participants: Patients presenting for cardiac surgery requiring TEE. Interventions: Multiplane TEE including 2 atrial views with color-flow Doppler (CFD) and contrast echocardiography (CE) with a provocative respiratory maneuver (PRM) and comparison of multiplane TEE and VI with respect to PFO detection. Measurements and Main Results: The cohort size was 187. PFO prevalence was 27.3%. CFD with serial decrease of the Nyquist limit detected 51% of all PFO: 41.2% in the bicaval view alone, 27.5% in the 4-chamber view alone, and 9.8% in both views. CE detected 78.4% of all PFO: 72.5% with PRM, 45.1% with no PRM, and 27.4% with/without PRM. PFO detection by multiplane TEE and visual inspection were correlated in 41 subjects. TEE diagnosed 11 PFO (26.8% prevalence, 3 missed by VI). VI diagnosed 12 PFO (29.3% prevalence, 4 missed by TEE). Conclusions: Multiplane TEE is a gold standard for detection of PFO. Despite advances in TEE technology, 2-dimensional imaging does not detect all PFO. To maximize PFO detection, multiple TEE modalities are required in multiple views, despite a low Nyquist limit for CFD or a PRM for CE. Even though multiplane TEE is equivalent to VI for PFO detection, the discrepancy rate may be an important consideration in the individual case.

Invited commentary

Emergency pulmonary embolectomy is often performed within a short time frame from diagnosis, without extensive preoperative workup, with the surgeon focusing on the removal of clot from one area: the large pulmonary arteries. In the above study, Rosenberger and associates provide evidence that transesophageal echocardiography (TEE) is a useful adjunct to planning operative strategy and guiding the surgical approach to acute embolism in the chest. Those of us using TEE routinely for cardiac operations do so believing that its benefits far outweigh its relatively low risk and cost. There are few clinical studies, however, actually proving its worth. By conducting a systematic investigation of the utility of TEE for emergency pulmonary embolectomy, the authors have made a valuable contribution that may guide the practice of other surgeons performing this operation. The results presented mirror our experience at the University of California, San Diego, with pulmonary thromboendarterectomy (PTE) for chronic thromboembolic disease [1Jamieson SW, Kapelanski DP, Sakakibara N, et al. Pulmonary endarterectomy—experience and lessons learned in 1500 cases. Ann Thorac Surg 2003;1456–64Google Scholar]. We find TEE to be important in the assessment of right ventricular structure and function, right atrial size, tricuspid regurgitation, left-sided filling characteristics, diagnosis of extrapulmonary thrombus, and detection of intracardiac air at the conclusion of the procedure. There are two assessments, in addition to those mentioned by the authors, we find useful in our PTE patients. The first is the midesophageal ascending aortic short-axis view, which, in addition to being the preferred view for examination of the right pulmonary artery, provides a view of the upper portion of the superior vena cava (SVC). This, being above the level of the bicaval view, allows assessment of an additional portion of the SVC for thromboembolic material. Second, we perform an agitated “bubble test” for the detection of a patent foramen ovale (PFO). Acute pulmonary embolism patients, as well as patients with chronic thromboembolic pulmonary hypertension, may experience instances in which right atrial pressure exceeds left atrial pressure, placing them at risk for paradoxical embolus. It is our experience that the agitated saline test with TEE is highly sensitive (more so than transthoracic echocardiography) for the detection of PFO, and PTE patients benefit from having the PFO closed intraoperatively. We would think that such a test would be beneficial in acute pulmonary embolectomy patients, even if a transthoracic study had been done. We believe TEE to be essential in the management of patients undergoing pulmonary artery surgery, and appreciate the work of the authors in clarifying this issue. Perhaps pulmonary artery surgery will soon join mitral valve repair, complex aortic reconstruction, and assessment of unexplained hemodynamic instability as a “class I” indication for perioperative TEE.