Comparison of intraoperative transesophageal echocardiography to epicardial imaging in children undergoing ventricular septal defect repair

Intraoperative epicardial echocardiography or transoesophageal echocardiography in CHD: how much does it matter?

BACKGROUND

Intraoperative imaging determines the integrity of surgical repairs. Transoesophageal echocardiography represents standard care for intraoperative imaging in CHD. However, some conditions preclude its use, and epicardial echocardiography is used alternatively. Minimal literature exists on the impact of epicardial echocardiography versus transoesophageal echocardiography. We aimed to evaluate accuracy between the two modalities and hypothesised higher imaging error rates for epicardial echocardiography.

METHODS

We retrospectively reviewed all epicardial echocardiograms performed over 16 years and compared them to an age- and procedure-matched, randomly selected transoesophageal echocardiography cohort. We detected un- or misidentified cardiac lesions during the intraoperative imaging and evaluated patient outcomes. Data are presented as a median with a range, or a number with percentages, with comparisons by Wilcoxon two-sample test and Fisher's exact test.

RESULTS

Totally, 413 patients comprised the epicardial echocardiography group with 295 transoesophageal echocardiography matches. Rates of imaging discrepancies, re-operation, and incision infection were similar. About 13% of epicardial echocardiography patients had imaging discrepancies versus 16% for transoesophageal (p = 0.2352), the former also had smaller body sizes (p < 0.0001) and more genetic abnormalities (33% versus 19%, p < 0.0001). Death/mechanical support occurred more frequently in epicardial echocardiography patients (16% versus 6%, p < 0.0001), while hospitalisations were longer (25 versus 19 days, p = 0.0003).

CONCLUSIONS

Diagnostic accuracy was similar between patients undergoing epicardial echocardiography and transoesophageal echocardiography, while rates of death and mechanical support were increased in this inherently higher risk patient population. Epicardial echocardiography provides a reasonable alternative when transoesophageal echocardiography is not feasible.

Epicardial Echocardiography in Pediatric and Congenital Heart Surgery

Epicardial echocardiography (e-echo) is a useful approach to intraoperative imaging for the smallest patients and in those with contraindications to transesophageal echocardiography (TEE). The e-echo has additional advantages that include improved visualization of anterior and vascular structures and three-dimensional capabilities. In this review, we describe the advantages and disadvantages of e-echo versus TEE for pediatric and congenital heart surgery with the goal of enhancing the utility and feasibility of the former among congenital heart surgeons. We also review the technique for performance of an e-echo and provide demonstrations of the images obtained for select lesions.

Spontaneous closure of small residual ventricular septal defects after surgical repair

BACKGROUND

Residual shunts may be detected by intraoperative or postoperative echocardiography after surgical closure of a ventricular septal defect (VSD). The hemodynamic relevance and rate of late closure are unknown.

METHODS

Between 1994 and 2005, 198 consecutive patients underwent surgical correction of an isolated VSD (n = 100), tetralogy of Fallot (n = 52) or atrioventricular septal defect (n = 46). Intraoperative transesophageal echocardiography (TEE) was routine, and postoperative transthoracic echocardiography was performed in the intensive care unit, at hospital discharge, and during follow-up. Residual defects were graded as absent, between 1 and 2 mm, or greater than 2 mm.

RESULTS

Shunt-related discrepancy was observed between intraoperative TEE and intensive care unit transthoracic echocardiographic findings; significantly so after Fallot repair (p < 0.0001). After discharge, 83% of all residual defects less than 2 mm closed. Of nine residual defects greater than 2 mm, only three closed after a median follow-up of 3.1 years. In patients with residual shunts, they were hemodynamically insignificant, required no medication, and no endocarditis was noted. At last follow-up, there was no significant difference between the percentage of residual shunts among the three groups (p = 0.135).

CONCLUSIONS

Postsurgical residual VSDs less than 2 mm closed spontaneously in the majority within a year. Defects greater than 2 mm are unlikely to close spontaneously. Residual shunts after atrioventricular septal defect repair almost always close, whereas one third will remain open after Fallot or isolated VSD repair. At midterm follow-up, residual shunts remained hemodynamically and clinically irrelevant. Revision of a residual defect greater than 2 mm on cardiopulmonary bypass at initial repair, guided by TEE, may spare late redo surgery and lifelong antibiotic prophylaxis.

Intraoperative Echocardiography in Pediatric Heart Disease

Intraoperative echocardiography has become an invaluable diagnostic and monitoring technique in surgery for pediatric heart disease. Transesophageal echocardiography (TEE) has largely replaced epicardial echocardiography as the pre ferred approach. TEE has the advantage of allowing serial assessment of anatomy and function with no interruption of surgery. Recent advances in transducer technology of the TEE probe and the introduction of novel modes of imaging have greatly increased the applicability of TEE in pediatric congenital cardiac repair. TEE has been used for a spectrum of congenital lesions such as valve anomalies, shunts, ob structions, and complex heart defects, as well as to monitor for myocardial ischemia and left ventricular preload. Expe rience and evidence suggest that intraoperative TEE can improve clinical outcomes in children undergoing repair of congenital cardiac defects. The safety and efficacy of TEE in children have been well established. This article outlines the development of intraoperative echocardiography and dis cusses TEE as a diagnostic tool in the management of pedi atric heart disease.

Reliability of intraoperative transesophageal echocardiography during Tetralogy of Fallot repair

There is limited information available concerning the accuracy of intraoperative transesophageal echocardiography (TEE) in predicting the extent of residual abnormalities after recovery from surgical repair of tetralogy of Fallot. Therefore, we investigated differences between the results of final postbypass TEE and those of postrecovery (mean, 6 days after surgery) transthoracic echocardiography in a total of 28 consecutive pediatric patients who underwent repair of tetralogy of Fallot with biplane or multiplane TEE. Both postbypass and postrecovery echocardiographic examinations included measurements of the right ventricle (RV)-main pulmonary artery (PA) and the main PA-branch PA peak instantaneous gradients, the degree of pulmonary valvar insufficiency, and color Doppler interrogation of the ventricular septum for residual defects. The RV-main PA gradient did not change significantly: 15 +/- 13 vs 18 +/- 14 mmHg (postbypass versus postrecovery, mean +/- SD). None of the patients had a decrease of > or = 10 mmHg; and only one patient had an increase of > or = 15 mmHg. There also was no change in the degree of pulmonary insufficiency (3.0 +/- 1.2 versus 3.1 +/- 1.1, using a scale of 0 to 4). Only one of the seven very small (< or = 2 mm) residual ventricular septal defects was not discovered during postbypass TEE. However, postrecovery transthoracic echocardiography detected significant branch PA stenosis (peak gradient, > or = 15 mmHg) in five patients (18%) that was not detected during postbypass TEE (P < 0.03). Of the branch PA stenoses that were not detected during TEE, four were left and one was right.

CONCLUSIONS

Postbypass TEE after tetralogy of Fallot repair reliably predicts residual postrecovery hemodynamic abnormalities, except for branch PA stenosis.

Feasibility study: transesophageal echocardiography with a 10F (3.2-mm), multifrequency (5.5- to 10-MHz) ultrasound catheter in a small rabbit model

Transesophageal echocardiography (TEE) is useful in children with congenital heart defects. However, because of available probe size (>/=7 mm diameter), its use is limited to patients weighing more than 3 kg. The aim of this study was to determine the feasibility of TEE in a small animal model by using a 10F (3.2-mm) intravascular ultrasound tipped catheter with a monoplane (longitudinal) 5.5- to 10-MHz phased vector array transducer. Ten New Zealand White rabbits (400 to 3400 g; mean 1580 g) underwent TEE. With animals under general sedation, the probe was blindly introduced into the esophagus. All intracardiac and extracardiac structures were examined, and the images were stored and independently reviewed. All pertinent intracardiac and extracardiac structures were identified except in the 3 smallest rabbits (400 to 600 g). Doppler hemodynamics and color Doppler were possible in each animal. Frequency agility (5.5 to 10 MHz) facilitated optimization of image resolution and penetration. Certain transgastric, 4-chamber, and short-axis views were limited because of the monoplane array. No overt adverse effects were associated with the procedure. Diagnostic TEE can be performed in a small animal model with a 10F, 5.5- to 10-MHz phased vector array ultrasound catheter. Our study suggests that this system has potential in performing diagnostic TEE safely in small, even premature, neonates.

Intraoperative transesophageal echocardiography in congenital heart disease

This article reviews the use of intraoperative echocardiography during repair of congenital heart defects. Although initial experience was generated using epicardial transducers, there has been a trend in recent years toward the use of transesophageal echocardiography (TEE) in the operating room. This has encouraged increased involvement from cardiologists and anesthesiologists. New probe designs have provided biplane imaging via the TEE approach in infants weighing more than 2.5 kg. Smaller infants may still require epicardial imaging, so it is helpful for surgeons to maintain some skill in this technique. This article reviews the utility of intraoperative echocardiography for various congenital heart defects by providing examples from our experience at Duke University Medical Center since 1987 with close to 2,000 cases. Furthermore, we review and report for the first time our experience with TEE since 1993 in the operating room during infant heart surgery (493 patients). Along with this experience, we provide a review of important series in the literature to outline recommendations for the use of echocardiography during infant heart repair.

Intraoperative transesophageal echocardiography using high-resolution biplane 7.5 MHz probes with continuous-wave Doppler capability in infants and children with tetralogy of Fallot

This study reports the role of biplane transesophageal echocardiography in monitoring surgical repairs of tetralogy of Fallot. In our patients, 3 repairs were revised based on transesophageal echocardiography and continuous-wave Doppler results, and intraoperative management was altered in 2 others.

Biplane intraoperative transesophageal echocardiography in congenital heart disease

OBJECTIVE

To evaluate the accuracy, value, and safety of biplane intraoperative transesophageal echocardiography (TEE) in patients with congenital cardiac malformations.

DESIGN

We reviewed the results of the first 104 consecutive biplane intraoperative TEE examinations performed during the repair of congenital heart defects at the Mayo Clinic.

MATERIAL AND METHODS

TEE results were analyzed for accuracy of diagnosis, effect on the surgical procedure, and associated complications. In a subjective analysis, the relative contributions and advantages of each imaging plane (transverse and longitudinal) were also assessed.

RESULTS

Biplane TEE had "significant impact" on intraoperative management in 17 of 104 examinations (16.3%). Preoperative TEE altered the planned procedure in 11 patients (10.6%). Postbypass biplane TEE led to immediate revision of the initial repair in nine patients (8.7%). Patients who underwent modified Fontan operations or subaortic resections had the greatest frequency of significant impact (40% [P = 0.006] and 33% [P = 0.03], respectively). No major complications were associated with TEE. For a complete examination, use of both imaging planes was necessary in all the patients studied.

CONCLUSION

Biplane TEE is an accurate, valuable, and safe addition to the perioperative care of patients with congenital heart disease. Although intraoperative TEE is not needed in all operations for congenital heart disease, we recommend that biplane intraoperative TEE be performed routinely during modified Fontan procedures, subaortic resections, and other intracardiac operations for complex congenital cardiac malformations.

Evaluation of ventricular septal defect by transesophageal echocardiography: intraoperative assessment

The miniaturization of transesophageal echocardiography (TEE) probes, together with the development of the capability for biplane imaging from the esophagus, have increased the use of TEE in pediatric cardiology. The aim of this study was to evaluate the TEE findings in patients with ventricular septal defect (VSD) before and after closure primarily by means of pediatric biplane probes. This study group included 69 patients who underwent VSD closure as an isolated repair or as a part of a definitive repair of a more complicated lesion. Ages ranged from 6 days to 15.6 years (median 1 year, 4 months), with operative weights ranging from 2.9 kg to 68 kg (median 10 kg). Preoperative and follow-up transthoracic echocardiograms (TTE) were also performed. Intraoperative TEE was performed without complication in all 69 patients. Preoperative results: (1) anatomic findings: Two muscular VSDs were detected by matrix TEE but could not be observed by TTE. A patient with preoperative TTE diagnosis of an ostium primum ASD was found to have atrioventricular (AV) canal by TEE. In three of six AV canal type VSDs, both TTE and TEE demonstrated left ventricular-right atrial shunting (2) aortic regurgitation associated with VSD: Aortic regurgitation as a result of right coronary cusp prolapse was detected in one of five supracristal VSDs in which the biplane or matrix TEE was used.(ABSTRACT TRUNCATED AT 250 WORDS)

Echocardiographic assessment of adults with tetralogy of Fallot

Advances in medical and surgical management of congenital heart disease in the last three decades have resulted in a great many survivors to adulthood. Proper care requires intimate knowledge of the basic malformations and their surgical anatomy and results. Tetralogy of Fallot, the most common cyanotic malformation in adults, represents a spectrum from mild right ventricular outflow tract obstruction to complete pulmonary atresia. Evaluation of surgical residua and sequelae includes imaging of aortic-to-pulmonary arterial palliative shunts, detection of residual ventricular septal defect patch leaks or right ventricular outflow tract obstruction, definition of extracardiac conduit patency, and quantitation of ventricular function and valvular regurgitation. Refined echocardiographic imaging and hemodynamic definition is a mainstay in precise segmental anatomical and hemodynamic assessment. Transesophageal echocardiography is particularly important for intraoperative evaluation of surgical results.