Baseline Transesophageal Echocardiography Research Articles

Consistency of transesophageal echocardiography and angiography in grading paravalvular regurgitation during transcatheter aortic valve replacement.

The Valve Academic Research Consortium 3 (VARC-3) standardizes the classification criteria and Doppler parameters for paravalvular regurgitation (PVR) by echocardiography. However, the consistency between transesophageal echocardiography (TEE) and angiography in grading (using the VARC-3 criteria) of PVR during transcatheter aortic valve replacement (TAVR) is unclear. Forty-six patients who underwent TEE and angiography during TAVR were retrospectively included. All patients had complete baseline information, TEE and angiography data. The Doppler parameters measured by TEE included the circumferential extent of PVR, regurgitation volume, regurgitation fraction, and the effective regurgitant orifice area. PVR was classified into four grades: absent, mild, moderate and severe. The weighted kappa coefficient was used to analyze the consistency between the two techniques. Kendall's W coefficient was used to evaluate the consistency of parameters measured by TEE. Among all patients, there were 43 cases (93.5%) with consistent assessments between TEE and angiography. PVR was observed in 19 cases. TEE assessed mild PVR in 17 cases and moderate PVR in two cases; Angiography assessed mild PVR in 14 cases and moderate PVR in two cases. The weighted kappa coefficient between angiography and the circumferential extent of PVR, regurgitation volume, regurgitation fraction, and the effective regurgitant orifice area respectively was .84, .79, .74, .85 (P < .001). Kendall's W coefficient was .83 (P < .001). TEE and angiography had strong consistency in the grading (using the VARC-3 criteria) of PVR during TAVR. TEE was a convenient diagnostic tool to quantify and grade PVR during TAVR.

Left atrial appendage anatomical changes following radiofrequency-based ostial isolation

Abstract Funding Acknowledgements Type of funding sources: None. Background Left atrial appendage (LAA) electrical isolation (ei) may be achieved via radiofrequency (RF) energy applications at the level of the appendage ostium targeting the sites of earliest activation recorded by a mapping catheter. Notably, RF has long been used in vascular, orthopedic, and aesthetic surgery to promote thermal-induced collagen matrix contraction, fibrosis, and tissue retraction. LAA anatomical changes associated to RF-induced tissue retraction have never been reported. Purpose To quantify the anatomical changes of the LAA ostium following RF-based LAAei. Methods Thirty-four consecutive patients requiring AF ablation with LAAei underwent transesophageal echocardiography (TEE) within 7 days before (baseline TEE) and apx 6 months after (follow-up TEE) ablation. The diameter of LAA orifice and landing zone were measured at 4 different views (0°, 45°, 90°, 135°). Measurements were performed by two independent reviewers blinded to the patient’s identity. Results Among 43 AF patients (67±6yrs, 72.1% males), the LAA morphology was classified as chicken wing in 19 (44.2%) patients, windsock in 12 (27.9%), cactus in 8 (18.6%), and cauliflower in 4 (9.3%). At baseline TEE, the mean maximum and mean minimum ostial diameters were 25±4mm and 22±4mm, respectively. The mean maximum and mean minimum diameters of the landing zone were 26±4mm and 23±3mm, respectively. On average, LAAei was achieved after 17±6 minutes of RF at a power of 45W. Follow-up TEE was performed 294±136 days after LAAei. The median LAA contraction velocity was 0.1 m/s (IQR: 0.02-0.18) and was significantly impaired in all patients. At follow-up TEE, the mean maximum and mean minimum ostial diameters were 19±4mm and 17±3mm, respectively. The mean maximum and mean minimum diameters of the landing zone were 20±4mm and 18±4mm, respectively. The mean relative reduction of the ostium and the landing zone was -24.4% and -22.5%, respectively. Box-Whisker plots of the maximum and minimum ostial diameters before and after LAAei are reported in Fig.1. Conclusion RF led to a &amp;gt;20% reduction of the diameters of the ostium and the landing zone. These changes may have important implications for a successful percutaneous occlusion procedure and justify a staged approach of isolation and occlusion.

Prevalence, predictors and management of left atrial appendage thrombogenic milieu in atrial fibrillation with low thromboembolic risk

BackgroundThe present study aimed to investigate the prevalence, predictors, and management of left atrial appendage (LAA) thrombogenic milieu (TM) identified with transesophageal echocardiography (TEE) in non-valvular atrial fibrillation (NVAF) patients with low to moderate thromboembolic (TE) risk.MethodsWe retrospectively analyzed the baseline clinical data and TEE findings in 391 NVAF patients (54.7 ± 8.9 years, 69.1% male) with low to moderate TE risk according to the CHA2DS2-VASc score. LAA TM was defined as LAA thrombus (LAAT), sludge or spontaneous echo contrast (SEC). Management of LAA TM was at the discretion of the treating physician.ResultsA total of 43 patients (11.0%) were detected with LAA TM, including 5 with LAAT (11.6%), 4 with LAAT + Sect. (9.3%), 3 with sludge (7.0%), and 31 with Sect. (72.1%). In multivariate model, non-paroxysmal AF (OR 3.121; 95% CI 1.205–8.083, p = 0.019), and a larger left atrial diameter (LAD) (OR 1.134; 95% CI 1.060–1.213, p < 0.001) were significantly associated with the presence of LAA TM. All LAATs or sludges effectively resolved after mean duration of 117.5 ± 20.0 days for oral anticoagulant (OAC) medication. TE events occurred in 3 patients (18.8%) among those discontinuing OAC over a mean follow-up of 26.2 ± 8.8 months, while no TE events occurred in patients with continuous OAC.ConclusionsLAA TM could be identified in 11.0% in NVAF patients with low to moderate TE risk, especially in those with non-paroxysmal AF and enlarged LAD. Short-term OAC medication could effectively resolve the LAAT or sludge.

P4 LEFT ATRIAL APPENDAGE ANATOMICAL CHANGES FOLLOWING RADIOFREQUENCY–BASED OSTIAL ISOLATION

Abstract Background Left atrial appendage (LAA) electrical isolation (ei) may be achieved via radiofrequency (RF) energy applications at the level of the appendage ostium targeting the sites of earliest activation recorded by a mapping catheter. Notably, RF has long been used in vascular, orthopedic, and aesthetic surgery to promote thermal–induced collagen matrix contraction, fibrosis, and tissue retraction. LAA anatomical changes associated to RF–induced tissue retraction have never been reported. Objective To quantify the anatomical changes of the LAA ostium following RF–based LAAei. Methods Thirty–four consecutive patients requiring AF ablation with LAAei underwent transesophageal echocardiography (TEE) within 7 days before (baseline TEE) and &amp;gt;6 months after (follow–up TEE) ablation. The diameter of LAA orifice and landing zone were measured at 4 different views (0°, 45°, 90°, 135°). Measurements were performed by two independent reviewers blinded to the patient’s identity. Results Among 34 AF patients (68±7yrs, 73.5% males), the LAA morphology was classified as chicken wing in 15 (44%) patients, windsock in 10 (29%), cactus in 6 (18%), and cauliflower in 3 (9%). At baseline TEE, the mean maximum and mean minimum ostial diameters were 25±4mm and 22±4mm, respectively. The mean maximum and mean minimum diameters of the landing zone were 26±4mm and 23±3mm, respectively. On average, LAAei was achieved after 16±7 minutes of RF at a power of 45–47W. Follow–up TEE was performed 257±148 days after LAAei. The median LAA contraction velocity was 0.1 m/s (IQR: 0.04–0.18) and was significantly impaired in all patients. At follow–up TEE, the mean maximum and mean minimum ostial diameters were 19±4mm and 17±3mm, respectively. The mean maximum and mean minimum diameters of the landing zone were 20±4mm and 18±4mm, respectively. The mean relative reduction of the ostium and the landing zone were –24.4% and –22.5%, respectively. Box–Whisker plots of the maximum and minimum ostial diameters before and after LAAei are reported in Fig. 1. Conclusion RF led to a &amp;gt; 20% reduction of the diameters of the ostium and the landing zone. These changes may have important implications for a successful percutaneous occlusion procedure and justify a staged approach of isolation and occlusion.

PO-696-07 LEFT ATRIAL APPENDAGE ANATOMICAL CHANGES FOLLOWING RADIOFREQUENCY-BASED OSTIAL ISOLATION

Left atrial appendage (LAA) electrical isolation (ei) may be achieved via radiofrequency (RF) energy applications at the level of the appendage ostium targeting the sites of earliest activation recorded by a mapping catheter. Notably, RF has long been used in vascular, orthopedic, and aesthetic surgery to promote thermal-induced collagen matrix contraction, fibrosis, and tissue retraction. LAA anatomical changes associated to RF-induced tissue retraction have never been reported. To quantify the anatomical changes of the LAA ostium following RF-based LAAei. Thirty-four consecutive patients requiring AF ablation with LAAei underwent transesophageal echocardiography (TEE) within 7 days before (baseline TEE) and >6 months after (follow-up TEE) ablation. The diameter of LAA orifice and landing zone were measured at 4 different views (0°, 45°, 90°, 135°). Measurements were performed by two independent reviewers blinded to the patient’s identity. Among 34 AF patients (68±7yrs, 73.5% males), the LAA morphology was classified as chicken wing in 15 (44%) patients, windsock in 10 (29%), cactus in 6 (18%), and cauliflower in 3 (9%). At baseline TEE, the mean maximum and mean minimum ostial diameters were 25±4mm and 22±4mm, respectively. The mean maximum and mean minimum diameters of the landing zone were 26±4mm and 23±3mm, respectively. On average, LAAei was achieved after 16±7 minutes of RF at a power of 45-47W. Follow-up TEE was performed 257±148 days after LAAei. The median LAA contraction velocity was 0.1 m/s (IQR: 0.04-0.18) and was significantly impaired in all patients. At follow-up TEE, the mean maximum and mean minimum ostial diameters were 19±4mm and 17±3mm, respectively. The mean maximum and mean minimum diameters of the landing zone were 20±4mm and 18±4mm, respectively. The mean relative reduction of the ostium and the landing zone was -24.4% and -22.5%, respectively. Box-Whisker plots of the maximum and minimum ostial diameters before and after LAAei are reported in Fig.1. RF led to a >20% reduction of the diameters of the ostium and the landing zone. These changes may have important implications for a successful percutaneous occlusion procedure and justify a staged approach of isolation and occlusion.

AN UNEXPECTED INTRAOPERATIVE UNUSUAL CASE OF AORTIC STENOSIS

Introduction Aortic stenosis is the most frequent valvular pathology in the developed countries (1). It is most often due to the calcified or degenerated aortic valve as a manifestation of ageing. Sub-valvular aortic stenosis is rare in the adult population being more common in children accounting for 8-20% of left ventricular outflow tract (LVOT) obstructions (2). Stenosis degree may change depending on the malformation varying from a minor ridge to a complete fibrous ring or tunnel. Although proper timing for surgery is unclear, diagnosis might be more difficult in the adult patient with transthoracic echocardiography as subvalvular portions of the LVOT might be shaded by calcium and difficult to visualize. We report a case of a 65 years old lady diagnosed with severe aortic stenosis and scheduled for aortic valve surgery. Methods The patient presented to our department with recent history of shortness of breath and clinical and transthoracic echocardiographic diagnosis os severe aortic stenosis. The maximum blood velocity across the aortic valve was 4.8 m sec-1 at continuous Doppler sampling. She was scheduled for aortic valve replacement. After establishing hemodynamic monitoring, general anaesthesia induction was performed with remifentanil, propofol and cisatracurium and maintained as TIVA. According to our protocol, a transesophageal echocardiography (TEE) was positioned and a baseline TEE was performed. Results TEE demonstrated a massive concentric hypertrophy of the left ventricle, a membranous subaortic stenosis and a normal aortic valve (fig. 1A,1B,1C). Surgery was then halted as the patient's written consent had been obtained for a valve replacement. Then the patient was further investigated by ECG gated cardiac CT scan, which confirmed the subvalvular membrane. The patient was then operated to remove the subvalvular membrane and a partial septal myectomy was also executed (fig 1D). She completely recovered and was discharged home on p.o. day 5. Discussion Differential diagnosis between aortic valvular stenosis or stenosis due to a subvalvular obstruction might be tricky, but is crucial for the operation result. TEE 2D and 3D imaging recognised the anomaly prior to surgery and so allowed to properly address the cardiac disease leading to post-operative success. Perioperative TEE should be performed in a systematic manner according to the current guidelines (3), but beyond the level of re-confirming the expected findings prior to surgery. TEE allowed for rapid and thorough recognition of previously undiscovered pathology leading to proper patient's management and case resolution, so confirming the importance of perioperative TEE in the setting of surgical treatment of heart valve diseases.

Abstract 17230: Transcatheter Leak Occlusion With Endovascular Coils Following Left Atrial Appendage Closure

Introduction: The Transcatheter Leak Closure With Detachable Coils Following Incomplete Left Atrial Appendage Closure Procedures (TREASURE) is a prospective, nonrandomized, single-center study. This study was undertaken to investigate the efficacy of transcatheter leak closure with endovascular coils in patient with incomplete percutaneous/epicardial left atrial appendage (LAA) closure procedures and high thromboembolic (TE)- and bleeding-risk. Hypothesis: We report the efficacy of transcatheter leak closure with endovascular coils in patients with incomplete LAA closure. Methods: Sixty-five consecutive patients with a clinically relevant residual leak (mean age: 72±8 years; 73.8% males; CHA 2 DS 2 -VASc: 4.7±1.1; HAS-BLED: 3.7±0.7) underwent percutaneous closure of the LAA patency via embolization coils. Trans-esophageal echocardiography (TEE) was performed at 60±15 days post-procedure. Results: LAA closure had been previously attempted with a Watchman device in 62 patients, and a LARIAT in 3. Baseline TEE documented a moderate or severe leak in 14 (21.5%) and 51 (78.5%) patients, respectively. Procedure and fluoroscopy times were 69±37min and 22±15min, respectively; the mean volume of iodinated contrast medium used was 82±43mL. Coil deployment was successful in all cases [median n. of coils attempted: 3 (IQR:2-5); median n. of coils deployed: 3 (IQR: 2-4)]. The overall complication rate was 3.1% (1 pericardial tamponade, 1 pericardial effusion). Peri-procedural angiographic and TEE outcomes demonstrated complete obliteration or a negligible residual opacification with a trivial residual jet in 62 cases (95.4%), and a partial occlusion with moderate residual jet in 3 (6.4%). Follow-up TEE after 67±12 days revealed complete LAA sealing or a negligible residual leak in 63 cases (96.9%). Coil deployment led to an average reduction of 90.1% in leak size (p&lt;0.001). After an overall follow-up of 17±4 months, no TE events were documented; 3 patients died from non-cardiovascular and one from cardiovascular causes (heart failure). Conclusions: Transcatheter LAA leak occlusion via endovascular coils appears to be a safe, effective, and promising approach in high TE-risk patients with incomplete LAA closure.

Impact of dense “smoke” detected on transesophageal echocardiography on stroke risk in patients with atrial fibrillation undergoing catheter ablation

Spontaneous echocardiographic contrast ("smoke") within the left atrial cavity on transesophageal echocardiography (TEE) suggests low blood flow velocities in the heart that may lead to thromboembolic (TE) events. The purpose of this study was to evaluate the risk of TE events in the periprocedural period and at long-term follow-up in atrial fibrillation (AF) patients having dense smoke on preprocedural TEE. A total of 2511 patients undergoing AF ablation were included in this analysis. They were classified as group 1 (dense smoke detected on TEE at baseline; n = 234) and group 2 (no smoke on baseline TEE; n = 2277). Patients were followed up for TE events, which included both stroke and transient ischemic attacks (TIAs). In order to attenuate the observed imbalance in baseline covariates between the study groups, a propensity score matching technique was used (covariates were age, sex, AF type, diabetes, and CHADS2VASc score). In the periprocedural period, no TE events were reported in group 1 and 3 events (0.13%) were reported in group 2. At follow-up of 6.62 ± 2.01 years, 6 (2.6%) TE complications (2 TIA, 4 stroke) occurred in group 1 and 16 (0.70%) TE complications (6 TIA, 10 stroke) in group 2 (P = .004). In the propensity-matched population, 6 (2.56%) TE complications occurred in group 1 and 1 (0.2%) in group 2 (P = .007). In our study population, the presence of dense left atrial smoke did not show any correlation with periprocedural TE events in patients undergoing catheter ablation with uninterrupted anticoagulation. However, significant association was observed with late stroke/TIA, irrespective of CHA2DS2-VASc score.

Risk Factors of Aortic Plaque Progression Evaluated by Long-Term Follow-Up Data With Transesophageal Echocardiography

There are few longitudinal data regarding aortic plaque. This study aimed to examine chronological changes in aortic plaques with transesophageal echocardiography (TEE), and to clarify the risk factors of aortic plaque progression. Among 2,675 consecutive patients who underwent TEE, we retrospectively investigated 252 patients who underwent follow-up TEE with an interval >3years. The thickness and morphology of aortic plaques were examined. Chronological changes in aortic plaques were investigated by comparing baseline and follow-up TEE. Clinical factors, laboratory data, and medications were evaluated. Among 252 study patients, the grade of aortic plaques was unchanged in 213 (group U), but progression was observed in 32 (group P) and regression in 7 patients (group R). Patients in group P were older; they had a higher prevalence of coronary artery disease, hypertension, smoking habit, and moderate or severe plaque at baseline TEE; more patients were using statins and no warfarin; and they had higher creatinine levels than those in group U. In multivariate analysis, moderate or severe plaques at baseline TEE were the strongest predictor of plaque progression. Among 50 patients who showed moderate or severe plaque at baseline TEE, smoking habit and no anticoagulation therapy were predictors of plaque progression. In conclusion, aortic plaques should be followed up using TEE in patients with moderate or severe plaque at baseline TEE.

Transesophageal Echocardiography in Swine: Establishment of a Baseline

The porcine model is a commonly used animal model in cardiovascular research. Along with new innovative operative techniques, choice of the optimal imaging technique is crucial. Transesophageal echocardiography (TEE) is a reliable imaging tool is highly important in a large number of experimental evaluations. But so far, TEE data for swine are limited, and few standard values have been established for the porcine model. The experience and baseline results for TEE in 45 swine are presented in this study. A full TEE examination was conducted in 45 German landrace or German large white swine, with an average body weight of 49 ± 3 kg, before experimental off-pump mitral valved stent implantation. Additionally hemodynamic measurements were evaluated. The valve implantation procedure was guided solely by real-time 3-D TEE. Baseline values of standard echocardiographic parameters are provided and, where appropriate, compared with human reference values. TEE proved to be an adequate imaging technique in this experimental porcine animal model. The baseline TEE and hemodynamic parameters established for the widely used porcine model can serve as a reference in future studies.

Prosthetic Valve Thrombosis in the Acute Phase of the Stroke: Relevance of Detection and Follow-Up

Stroke may be the first symptom of prosthetic valve thrombosis (PVT); therefore, rapid diagnosis and therapy are crucial. We aimed to evaluate the prevalence, main predictors, and long-term clinical evolution of patients with PVT in the acute phase of stroke. We studied consecutive acute ischemic stroke patients with prosthetic heart valves who underwent emergent transesophageal echocardiography (TEE) during a 5-year period. Two groups were defined depending on the presence of PVT (PVT or non-PVT groups). Baseline characteristics, TEE findings, and international normalized ratios (INRs) at the stroke event were registered. Follow-up visits and TEE control examinations were performed. Sixty-seven patients were registered. TEE was performed within the first week in 85% of patients (n = 57). PVT was diagnosed in 41.8% of cases (n = 28). Clinical severity and baseline INR level showed no differences when the PVT and non-PVT groups were compared. The presence of PVT was associated with the mitral valve location as compared with the aortic valve location (75% versus 25%, P = .003), the presence of spontaneous echocontrast (64.3% versus 35.9%, P = .022), and low ejection fraction (66.7% versus 32.7%, P = .019). The PVT group showed a trend toward higher percentage of recurrence (10.7% versus 2.5%, P = .102) in the follow up period (mean follow-up 25 months). The detection of PVT in the acute stroke phase was relevant, as the stroke recurrence rate was considerable. Therefore, all patients with prosthetic heart valve should undergo emergent TEE.

Transapical aortic valve replacement complicated by periaortic hematoma.

Abstract A 77-year-old woman with severe symptomatic aortic stenosis (aortic valve areaZ0.6 cm2 and mean gradientZ 53 mmHg) was deemed inoperable for surgical aortic valve replacement due to a porcelain aorta, and was scheduled for transcatheter aortic valve replacement via an apical approach. A 23 mm valve was selected based on a computerized axial tomographic angiography derived area of 360 mm2; valve oversizing was 15.4%. Baseline transesophageal echocardiography revealed severe protruding atheroma within the lumen of the ascending aorta. Immediately following deployment of the Sapien pericardial tissue valve (Edwards Life Sciences, Irvine, CA, USA), a large posterior periaortic hematoma was noted (1.3 cm in maximum width, and w4 cm in length) (see Fig. 1 and Videos 1, 2, 3, 4). Protamine was administered, and the hematoma was observed by transesophegeal echocardiography for w30 min with no change in size; function of the bioprosthetic valve was normal without regurgitation. In the immediate post-operative period, anti-platelet agents were withheld, and blood pressure was aggressively lowered. The remainder of her hospital course was uncomplicated, and a tranthoracic echocardiogram w1 month later demonstrated resolution of the hematoma. Periaortic hematoma and aortic root rupture are recognized potential major complications of transcatheter aortic valve replacement (1, 2). Severe left ventricular outflow tract calcification and annular over sizing are both risk factors for these complications. Careful transesophageal echocardiographic examination post valve deployment may lead to early recognition and treatment of this potentially fatal complication (3). In this case, presence of severe protruding atherosclerotic plaque pre-procedure likely predisposed to this complication.

Impact and Cost Effectiveness of Routine Intraoperative Transthoracic and Transesophageal Echocardiography on Surgical Decision Making in Pediatric Cardiac Surgery

ABSTRACTIntroductionCongenital heart diseases (CHD) present with wide spectrum of lesions leading to diagnostic dilemmas and it is quite possible to miss correct diagnosis during preoperative transthoracic echocardiography (TTE) in an inadequately sedated child, especially in a busy outpatient setting. It is a routine practice in our center to do baseline TTE after induction of anesthesia followed by pre and postcardiopulmonary bypass (CPB) transesophageal echocardiography (TEE) in all CHD patients thus helping us review our surgical plan.Materials and methodsAll pediatric patients &lt;18 years undergoing cardiac surgery from January 2013 to December 2013 at our tertiary care center in whom perioperative echocardiograhy was done were included. Appropriate sized TTE and TEE probes were used with the Philips iE33 echocardiography platform (Philips, Andover, MA).ResultsOut of total 352 pediatric cardiac surgical patients, perioperative echocardiography was done in 347(98.5%) patients. Baseline TTE showed new findings leading to change in surgical plan in 11 (3.1%) patients while additional new findings in baseline TEE were seen in 9 (2.6%). Post bypass TEE showed residual lesions requiring a CPB rerun in 19 (5.5%) patients. Intraoperative echocardiography was found to be cost effective with an estimated savings per patient of ₹ 3950 to 5373($61 - 83).ConclusionIntraoperative echocardiography is an important tool in armamentarium of perioperative physician which can be used to review diagnosis and help to formulate an informed surgical plan. Post-bypass transesophageal echocardiography is also useful as it identifies the residual lesions and establishes anatomical correction, which ultimately translates to lesser redo surgeries and a better postoperative outcome.How to cite this articleMishra A, Madhavan JS, Ghuman BPS, Raj R, Kumar A, Dutta V, Negi S, Tandon Y, Kumar A, Arya VK, Kumar B, Jayant A, Puri GD. Impact and Cost Effectiveness of Routine Intraoperative Transthoracic and Transesophageal Echocardiography on Surgical Decision Making in Pediatric Cardiac Surgery. J Perioper Echocardiogr 2014;2(1):3-9.

Endocardial occlusion of incompletely surgically ligated left atrial appendage using an Amplatzer septal occluder device

A 55-year-old man underwent a surgical Maze procedure for the treatment of nonvalvular atrial fibrillation with concomitant surgical suture ligation of left atrial appendage (LAA). Baseline transesophageal echocardiography (TEE) and computed tomography (CT) angiography revealed a normal LAA free of thrombus (Figure 1A). Ten days after surgery, he developed an acute embolic stroke. Repeat TEE and CT angiography demonstrated an incompletely surgically ligated LAA (ISLL) without thrombus, with the ISLL neck dimensions measuring 3 × 3 mm (Figure 1B).

The Role of Repeat Transesophageal Echocardiography in Patients without Atrial Thrombus Prior to Cardioversion or Ablation

Cardioversion (CV) and radiofrequency catheter ablation (RFA) are often used to restore sinus rhythm in patients with atrial fibrillation (AF). These procedures are associated with a risk for stroke. The use of transesophageal echocardiography (TEE) to guide the management of AF is a validated strategy for patients in whom CV is planned, as well patients before RFA. For patients in whom the initial procedure fails, repeat TEE is often performed before repeat CV or RFA. The aim of this study was to test the hypothesis that patients with initial negative results on TEE would be unlikely to have thrombi detected on subsequent TEE and thus may avoid repeat procedures. A total of 2,999 patients with AF were identified via retrospective review who had undergone TEE before CV or RFA, and 418 of these individuals underwent repeat TEE. After excluding patients who underwent repeat TEE >365 days from the initial study (n= 135) and those with thrombi on initial TEE (n= 20), 263 patients who had underwent two or more examinations were identified and analyzed. Of 263 eligible patients, two (0.8%; 95% confidence interval, 0.21-2.7%) had thrombi on subsequent TEE. Fewer than 1% of patients with AF with negative results on baseline TEE had thrombi detected on repeat TEE before subsequent CV or RFA. Thus, it may be possible to selectively screen patients to identify those at low risk for developing thrombi subsequent to negative results on initial TEE, especially if patients are in sinus rhythm. These results suggest the need for a prospective trial to definitively answer the question regarding repeat TEE in low-risk patients.

Transjugular intrahepatic portosystemic shunt related paradoxical air embolism during orthotopic liver transplantation

To the Editor, During the dissection phase of an orthotopic liver transplant, a 63 yr old man developed widespread ST depression and cardiovascular collapse. Transesophageal echocardiography (TEE) revealed air in both ventricles associated with new onset biventricular dilation and dysfunction. The surgeons found a failed staple line placed inadvertently across a transjugular intrahepatic portosystemic shunt (TIPS), which was now splinting the right hepatic vein open. Control of air entrainment was achieved with caval clamping. Trendelenberg positioning was employed to prevent air entering the right ventricular outflow tract. Following resuscitation, a full echocardiographic examination was undertaken. Air was seen extending into the aortic root but was not demonstrated in the coronary circulation. Patent foramen ovale (PFO) was not demonstrated on colour Doppler. A plausible explanation for this paradoxical air embolism is intrapulmonary shunting. Intrapulmonary shunt recruitment is thought to occur by a pressure dependent baffle mechanism exacerbated in this case by increased pulmonary artery pressures from air embolus. Potentially catastrophic hemodynamic changes occur frequently during orthotopic liver transplantation (OLT) and require rapid and accurate diagnosis. During the dissection phase, hepatic manipulation causes intermittent obstruction to venous return. The anhepatic phase involves clamping the portal vein and inferior vena cava, both of which cause a significant reduction in venous return. Reperfusion syndrome ([30% decrease in mean arterial pressure for at least 1 min) is seen in 42% of patients. Associated physiologic changes include increased pulmonary pressures, right ventricular dysfunction, bradycardia, acidosis, and hypothermia. Given the multiple causes of hypotension and hemodynamic instability during OLT, the assessment of cardiac preload and function is easily justified. In comparison with a pulmonary artery catheter, TEE has the distinct advantage of being a relatively non-invasive procedure. TEE allows direct visualization of the heart, permitting monitoring of volume status, contractility, and overall function. In addition, TEE provides valuable information when less common complications occur, such as large pleural effusions, tension pneumothorax, or pulmonary embolism. TEE is especially helpful in the management of disorders such as acute pulmonary hypertensive crisis, intracardiac clot formation, and hypertrophic cardiomyopathy. The initial fear of rupturing esophageal varices is an exceedingly uncommon complication and has not yet been reported despite widespread intra-operative use. We would like to raise four points: (1) baseline TEE for OLT should seek to specifically identify trans-pulmonary shunts; (2) liver transplant candidates may be at increased risk of paradoxical embolism even if they do not have a PFO or severe hepatopulmonary syndrome; (3) one should note the presence of a TIPS that may contribute to life threatening air emboli during liver dissection; and (4) TEE is increasingly used in liver transplantation and can aid in the rapid diagnosis of a potentially underestimated issue of OLT air embolism.

Perioperative Management of a Patient With a Nonpulsatile Left Ventricular–Assist Device Presenting for Noncardiac Surgery

A 55-year-old man supported by a VentrAssist LVAD (Ventracor Limited, Chatswood, Australia) presented for debridement and myocutaneous flap closure of a stage IV sacral decubitus ulcer in the prone position. The device had been implanted as a bridge to transplantation approximately 2 months previously, and the patient was hemodynamically stable. Additional procedures at the time of VAD implantation had included mitral valve replacement, aortic valve replacement, and coronary artery bypass graft surgery to the right coronary distribution. The postoperative course had been complicated by renal failure, anemia, and prolonged respiratory failure for which he had previously undergone tracheostomy, and he was chronically in atrial fibrillation. Medications included heparin infusion, hydromorphone, levetiracetam, cefazolin, levocarnine, quetiapine, darbopoeitin, and insulin. Physical examination revealed a cachectic male weighing 55 kg and measuring 165 cm tall. The driveline of the LVAD exited the abdomen at the left upper quadrant. There was an indwelling right femoral arterial pressure cannula and a 7.5F triple-lumen catheter in the right internal jugular vein. An 8.0 cuffed Shiley tracheostomy tube was present. The patient was transported to the operating room by the anesthesia team and a dedicated VAD nurse. Hemodynamic monitoring was used in transport, and the device was powered by battery packs. Upon arrival to the operating room, the VAD was returned to main AC power. Intraoperative monitoring included an electrocardiogram, pulse oximetry (SpO2), invasive arterial pressure, central venous pressure, transesophageal echocardiography (TEE), and cerebral oximetry (SctO2). In addition to the anesthesia team assigned to the case, a cardiac anesthesiologist and the VAD nurse were present intraoperatively. In addition to infusions of epinephrine and vasopressin, nitric oxide was available in the room, although the tank was not opened as a cost-containment effort. Vital signs on operating room arrival were heart rate of 70 beats/min, mean arterial pressure of 60 to 70 mmHg, central venous pressure of 14 mmHg, SpO2 of 100%, and left SctO2 of 70% and right of 60%. A thorough denitrogenation was accomplished through the tracheostomy, and induction of general anesthesia proceeded smoothly with midazolam (2 mg), fentanyl (250 g), etomidate (8 mg), and vecuronium (10 mg). Anesthesia was maintained with isoflurane in oxygen and additional boluses of vecuronium. After anesthetic induction in the supine position, TEE examination by a cardiac anesthesiologist revealed a dilated and severely hypokinetic left ventricle (LV), a well-functioning right ventricle (RV), absence of tricuspid regurgitation, a well-functioning mitral bioprosthesis, and an intact bioprosthetic aortic valve that was not opening. The inflow cannula to the LVAD could not be visualized in the left ventricular apex (likely because it is quite short with this particular device), but color-flow mapping revealed no apparent turbulence suggesting obstruction to inflow. Outflow from the device in the ascending aorta was visualized, but the outflow cannula itself could not be. Once the baseline TEE examination was completed, the patient was then turned from the supine to the prone position, with careful placement of abdominal and chest bolsters. The patient initially tolerated this position without significant change in arterial or airway pressures. By comparison to the baseline examination in the supine position, the TEE examination in the prone position revealed relatively decreased right ventricular function (Videos 1 and 2 [supplementary videos are available online]). Unfortunately, within just a few minutes (and before skin incision), the airway pressures suddenly increased, SctO2 decreased bilaterally, there was an abrupt loss of the capnogram tracing, and LVAD output rapidly decreased from 6.1 L/min to 3.8 L/min. The patient was immediately returned to the supine position. Attempted manual ventilation revealed significantly decreased lung compliance. Suctioning of the tracheostomy evacuated bloody secretions along with a large clot. Once the bloody plug had been removed, ventilatory parameters, LVAD flows, and SctO2 returned to their previously stable baseline values. Discussion with the surgeons resulted in the procedure being performed in the right lateral decubitus position to allow for better access to the airway during the surgery. The TEE examination revealed that the right-ventricular function had returned to baseline. The airway required suctioning multiple times throughout the procedure for bloody airway secretions, but LVAD flow rates remained steady at approximately 5.7 LPM throughout the remainder of the surgery. The SpO2 monitoring did function intermittently and indicated no oxygen desaturations during those periods. The SctO2 was reliable throughout the case and was stable. At the conclusion of the operation, the patient was transported back to the cardiothoracic ICU by the anesthesiologists, surgeons, and the LVAD nurse with the device running on battery power. DISCUSSION

Transesophageal Echocardiography Failed to Detect a Patent Foramen Ovale Resulting in Cardiac Arrest During Endoscopic Saphenous Vein Harvesting in Coronary Artery Bypass Grafting Surgery

To the Editor: Carbon dioxide (CO2) embolization is a complication of endoscopic saphenous vein harvesting with CO2 insufflation during coronary artery bypass surgery (1,2). Lin et al. (3), using transesophageal echocardiography (TEE) to monitor CO2 bubbles in the inferior vena cava and hepatic vein, demonstrated a 4% incidence of significant CO2 embolism during endoscopic saphenous vein harvesting with CO2 insufflation procedures. An abrupt decrease in end-tidal CO2 can be a sensitive monitor for detecting CO2 embolism if the cardiovascular function, body temperature, and respiratory status remain stable. However, in the presence of hemodynamic instability capnography can be unreliable. TEE is the most reliable and sensitive method to detect CO2 embolism and is now considered to be the “gold standard” for diagnosis (4). A 78-yr-old woman with a history of angina and hypertension presented for coronary artery bypass surgery. Cardiac catheterization revealed 80% occlusion of the left anterior descending artery, 90% stenosis of the circumflex artery, and 40% stenosis of the right coronary artery. The reported ejection fraction was 60%. She was scheduled for endoscopic saphenous vein harvesting and coronary artery bypass graft surgery. Intraoperative monitors included five-lead electrocardiogram (ECG), radial artery catheter, pulmonary artery catheter, pulse oximetry, capnography, temperature, and TEE. After induction of anesthesia, her baseline TEE revealed good left ventricular function, and normal segmental wall motion in all 16 segments. Color Doppler imaging and agitated saline injection failed to demonstrate a patent foramen ovale (PFO). Endoscopic saphenous vein harvesting with CO2 insufflation at 12 mm Hg was begun. Approximately 30 min after beginning dissection, we noted a transient decrease in her arterial blood pressure from 100/60 to 70/40 mm Hg, accompanied by an increase in end-tidal CO2 to 57 mm Hg. Oxygen saturation remained at 99% with a Fio2 at 100%. This was accompanied by severe bradycardia, and ST segment changes. Mid-esophageal four-chamber views demonstrated severe biventricular global hypokinesis, with diffuse echogenic bubbles completely filling the right atrium and partially filling the right ventricle. Bubbles we seen crossing a PFO into the left atrium and left ventricle, with subsequent macroembolization to the aorta and coronary arterial system. CO2 insufflation was discontinued and cardiopulmonary resuscitation was initiated. The patient was treated with atropine, 1 mg IV push, and epinephrine and norepinephrine IV infusions. Within several minutes the bubbles cleared from the cardiac chambers, right ventricle and left ventricle wall motion normalized, as did the ECG and arterial blood pressure. Subsequent repair of the four vessels, as well as a 2.3 cm PFO, proceeded without incident. The patient was tracheally extubated 12 hours after surgery, and had no neurological sequelae. She was discharged home on the 11th postoperative day. Yoshio Okumura, MD Rodney A. Batchelder, CRNA, MS Department of Anesthesia William Beaumont Hospital Troy, Michigan [email protected]

Does acute-phase beta blockade reduce left atrial appendage function in patients with chronic nonvalvular atrial fibrillation?

To investigate whether acute-phase beta-blocker therapy has a harmful effect on left atrial appendage (LAA) function in patients with chronic nonvalvular atrial fibrillation by transesophageal echocardiography (TEE), we evaluated 21 patients with normal left ventricular systolic function and a poorly controlled ventricular rate, despite the use of digoxin. Baseline parameters that were obtained included heart rate, blood pressure, LAA emptying velocities, and left atrial spontaneous echo contrast intensity. Then, each patient was given a bolus dose of 5 mg metoprolol. Ten minutes later, a second set of assessments was performed. After the first TEE studies, each patient began treatment with metoprolol (50 mg orally twice daily for 1 week). A second TEE study was performed after 1 week of continuous oral metoprolol therapy at maintenance dose, and values were again determined. The average resting apical heart rate was 91 ± 7 bpm. As expected, beta-blocker therapy showed a marked decrease in heart rate at 10 minutes (79 ± 6 bpm, P <.001) and at 1 week (71 ± 4 bpm, P <.001). Beta-blocker therapy caused a significant reduction in systolic and diastolic blood pressures (144 ± 16 / 93 ± 6 mm Hg at baseline, 137 ± 16 / 87 ± 9 mm Hg at 10 minutes, and 135 ± 12 / 86 ± 8 mm Hg at 1 week, P <.001). With the beta-blocker therapy, the baseline transesophageal Doppler parameter of LAA emptying velocities (at baseline 24 ± 7 cm/s) fell significantly at 10 minutes (19 ± 7 cm/s, P <.001) and at 1 week (17 ± 6 cm/s, P <.001) after initiation of beta-blocker therapy. After a bolus of metoprolol, spontaneous echo contrast intensity did not change in any patients, but 1 week later, it increased in 1 patient. In 2 patients who had not been found to have an LAA thrombus at baseline TEE study, the second TEE examination demonstrated new thrombi in the LAA. In conclusion, our findings suggest that in patients with chronic nonvalvular atrial fibrillation who have normal left ventricular systolic function and a poorly controlled ventricular rate despite the use of digoxin, acute-phase beta blockade may have a harmful effect on LAA function. (J Am Soc Echocardiogr 2001;14:194-9.)

Association of Follow-up Change of Left Atrial Appendage Blood Flow Velocity With Spontaneous Echo Contrast in Nonrheumatic Atrial Fibrillation

To evaluate the time-related change of left atrial (LA) appendage flow velocity in chronic atrial fibrillation (AF) by follow-up transesophageal echocardiography (TEE) and to investigate its association with the occurrence of LA spontaneous echo contrast. Prospective follow-up study. University-based, tertiary referral medical center. Forty-seven patients with chronic nonrheumatic AF. All studied patients underwent both a baseline and follow-up TEE during a mean period of 13 +/- 7 months. Baseline TEE revealed that LA spontaneous echo contrast was present in 28 patients (group 1) and was absent in 19 patients (group 2). The LA appendage flow velocity profiles at baseline were significantly lower in group 1 than in group 2; on follow-up, the appendage flow velocities decreased significantly in group 2, but were not significantly changed in group 1. Follow-up TEE revealed that spontaneous echo contrast was persistent in all group 1 patients. In group 2, LA spontaneous echo contrast was newly observed in 9 patients (group 2A) but was persistently absent in 10 patients (group 2B). In group 2A, all of the LA appendage flow velocity profiles decreased significantly at the follow-up study. In group 2B, however, only LA appendage inflow velocity integral showed significant decrease on follow-up; there were no significant changes in LA appendage outflow velocity indexes and peak inflow velocity. LA appendage flow velocity may decrease with time in some patients with AF, and this change is associated with a new occurrence of LA spontaneous echo contrast. For patients without LA spontaneous echo contrast, serial follow-up of the LA appendage flow velocity profiles may be useful for predicting future development of spontaneous echo contrast. Once LA spontaneous echo contrast occurs in AF patients, it tends to persist with time and the LA appendage is usually under a persistently low flow state.