Transesophageal Echocardiography: Intraoperative Applications

Role of Intraoperative Transesophageal Echocardiography in Patients Having Coronary Artery Bypass Graft Surgery

BACKGROUND

Previous studies have shown that intraoperative transesophageal echocardiography provides important preoperative and postoperative information in various cardiac and noncardiac surgeries that may alter patient management and outcome. The role of intraoperative transesophageal echocardiography in patients in whom isolated coronary artery bypass graft surgery is anticipated has been reported only in small selected groups. This study was designed to prospectively evaluate the role of intraoperative transesophageal echocardiography in a large, nonselected group of patients undergoing primarily coronary artery bypass graft surgery.

METHODS

From January 2001 to December 2003, 474 consecutive patients (76% men, 24% women) aged 30 to 89 years (mean age of 70 +/- 10 years) who were undergoing coronary artery bypass graft surgery had prebypass and postbypass intraoperative transesophageal echocardiography. New findings and alterations in the surgical plan were documented prospectively.

RESULTS

New prebypass findings were found in 10% of patients, and the surgical plan was altered in 3.4% of patients. New postbypass findings were found in 3.2% of patients, altering the surgical plan in 2% of patients.

CONCLUSIONS

This large consecutive, nonselected, prospective study reveals the significant impact of intraoperative transesophageal echocardiography in patients having coronary artery bypass graft surgery as a primary procedure. New findings (prebypass and postbypass) were found in 13% of patients overall, and the surgical plan was altered in 5.5% of patients. This study supports the use of intraoperative transesophageal echocardiography in patients undergoing primarily coronary artery bypass graft surgery.

Intraoperative transesophageal echocardiography: 5-year prospective review of impact on surgical management

OBJECTIVE

To determine the impact of intraoperative transesophageal echocardiography (IOTEE), an important adjunct in many types of cardiac surgical cases, on the surgical decisions made perioperatively in adult patients undergoing cardiac surgery.

PATIENTS AND METHODS

All adult patients who had cardiac surgery between 1993 and 1997 and who also had IOTEE were studied. New findings before and after cardiopulmonary bypass and alterations in the planned surgical procedure or management were documented prospectively.

RESULTS

A total of 3245 patients (60% men, 40% women; aged 18-93 years with a mean +/- SD age of 62 +/- 15 years) were included in the study. The most common operations performed were mitral valve repair (26%) and aortic valve replacement (22%). Over the 5-year period, 41% of patients had IOTEE. New information was found before bypass in 15% of patients, directly affecting surgery in 14% of the patients. The most common new prebypass information found was patent foramen ovale resulting in closure in the majority of patients. New information was found after bypass in 6% of the patients, resulting in a change in surgery or hemodynamic management in 4% of the total. The most common postbypass finding was valvular dysfunction with repeat bypass in most patients for re-repair or replacement. No major complications occurred.

CONCLUSION

In adult patients undergoing cardiac surgery, IOTEE provides important important information both before and after bypass that affects surgical and hemodynamic management.

Importance of intraoperative transesophageal echocardiography during coronary artery surgery without cardiopulmonary bypass

The goal of this study was to assess left ventricular segmental wall motion (SWM) abnormalities during coronary artery bypass grafting (CABG) without cardiopulmonary bypass (CPB), and its impact on the immediate postoperative outcome. Transesophageal echocardiography was used intraoperatively in 27 patients (mean age 57 years) who had CABG without CPB. Images obtained with a 5-MHz biplane transesophageal echocardiographic probe in the transgastric and transesophageal planes were recorded before, during, and after 48 coronary artery clampings for saphenous vein or internal mammary artery anastomosis. Transthoracic echocardiography was performed 1 day before surgery and on the seventh postoperative day. During the 48 coronary artery clampings, 31 (64%) new SWM abnormalities were found. At the time of chest closure, complete recovery occurred in 16 (50%) segments, partial recovery in 10 (33%), and no recovery in 5 (17%). On the seventh postoperative day the new SWM abnormalities persisted in all 5 segments without recovery at the end of the surgery and in 2 of 10 (20%)segments with partial recovery (group 1). Group 1 had higher variation on the echocardiographic point score index between the beginning and end of surgery, higher enzymatic levels, more ST-T changes on the electrocardiogram, and more clinical problems than group 2 (patients without new SWM abnormalities on the seventh postoperative day) (P < .05). We concluded that new SWM abnormalities of the left ventricle occur during CABG without CPB as assessed by intraoperative transesophageal echocardiography. Persistence of these abnormalities at the end of surgery may be a predictor of SWM dysfunction and clinical problems in the immediate postoperative period.

Establishment and First Audit of a New Perioperative Echocardiography Service

Intraoperative echocardiography has become an integral service for cardiothoracic surgery. Establishing a service requires new ultrasound technologies and a dedicated team prepared to be trained in this new discipline. The establishment of a new perioperative service at Westmead Hospital, Australia is outlined. Early experience, current practice, teaching and research programs are presented and the first audit is reported.

Role of echocardiography in perioperative management of patients undergoing open heart surgery

TEE has assumed a pivotal role in the perioperative management of patients undergoing open-heart surgery. The information obtained influences important therapeutic decisions in thoracic aortic surgery, valvular surgery, and coronary artery bypass surgery. TEE also assists in determining the reason for failure to wean from cardiopulmonary bypass and allows rapid detection of the etiology of hypotension in the patient after surgery. Advances in technology have resulted in three-dimensional images of cardiac structures, and this will further enhance the usefulness of echocardiography for the surgeon. TEE should no longer be regarded as an imaging tool available only in academic centers, but should be routinely used by qualified operators in centers performing open-heart surgery.

Regurgitant flow of mitral valve prostheses: an intraoperative transesophageal echocardiographic study

To assess the regurgitant characteristics of mitral biologic and mechanical prostheses immediately after implantation, intraoperative transesophageal echocardiography was performed in 27 patients, aged 32 to 69 years, undergoing open-heart surgery for rheumatic heart disease (n = 19), mitral valve prolapse (n = 3), malfunctioning prostheses (n = 3), or periprosthetic leaks (n = 2). The prostheses included 13 biologic (Carpentier-Edwards) and 14 mechanical valves (five Starr-Edwards, five Medtronic-Hall, and four Bjork-Shiley). Physiologic transvalvular regurgitant flow was detected in both biologic and mechanical prostheses. The spatial extent of the regurgitant jets was usually greater in the mechanical than in the biologic valves, and systolic jets, characteristic of each type of valve, were visualized consistently. Trivial periprosthetic jets (PPJs) were observed in many implanted valves (14/27). The median maximal jet area was 0.46 cm2 (range 0.1 to 1.5 cm2). Cardiopulmonary bypass was reinstituted in two patients. In one patient a PPJ was judged extensive enough (area 3.6 cm2) to warrant surgical revision of the implant, but no dehiscence was found. In the other patient a turbulent PPJ (area 5.5 cm2) was associated with a 0.5 cm dehiscence at the surgical inspection. In conclusion, (1) all mitral prostheses exhibit physiologic transvalvular regurgitation, (2) trivial mitral PPJ is a common finding in newly implanted mitral valves and does not require the revision of the implant, and (3) further experience based on larger series of patients is required to determine the maximal acceptable size of a mitral PPJ detected by intraoperative transesophageal echocardiography.

The role of transesophageal echocardiography in the monitoring of cardiac mass removal: a review of 17 cases

Intraoperative transesophageal echocardiography (TEE) was used to monitor the removal of intracardiac masses in 17 patients. Prebypass TEE was used to confirm the preoperative diagnosis. It gave a clear image and anatomical definition of the mass in 16 cases. Moreover, in 11 of these patients, prebypass TEE provided information not obtained previously by traditional exams. This information was judged either useful or indispensable for a successful outcome in 10 of these patients. However, in one of the remaining six patients, TEE did not clearly visualize a flat thrombus in the left atrium. Postbypass TEE was used in each case to monitor the surgical results of the mass removal and the associated procedures. In one patient, it disclosed a progressively expanding hematoma in the left atrial wall, which was interfering with mitral valve function. From this experience, we consider intraoperative TEE the best monitoring device during cardiac mass removal because it usually provides a more complete diagnosis and anatomical definition of the mass than the traditional preoperative methods and permits monitoring of the surgical results before chest closure. Some limitations to this method may exist.

Intraoperative echocardiography by a new miniaturized epicardial probe: preliminary findings

Miniaturized probes constitute recent progress in the field of epicardial echocardiography. We recently used a new miniaturized probe, derived from a standard transesophageal probe, in a series of 12 adult patients who underwent cardiac surgery in order to test the possibility of obtaining new views for epicardial imaging. This study demonstrates the feasibility and safety of performing intraoperative echocardiography when using a miniaturized epicardial probe. This probe may be placed on a broader epicardial and vascular area, thus overcoming the size limitations of the commonly used epicardial probes. The major limitation found with the miniaturized probe, however, was the inability to obtain a true four-chamber view from the ventricular apex, due to the difficulty of holding the probe motionless between the apex and the diaphragm while the heart is beating. Although extensive experience with larger groups of patients and different pathologies will be required to define the full potential of this new probe, the advent of the miniaturized probe may further expand the applicability of epicardial echocardiography in pediatric patients during surgery for congenital heart disease.

Attachment of a balloon to a transesophageal echocardiographic transducer for improvement of contact with the esophageal wall

We attached a water-inflated balloon to a transesophageal probe to improve contact of the transducer with the esophageal wall and used it in 26 patients with congenital heart disease. Balloons for this study were made for use in hemostatic therapy for esophageal varix. The contact of the transducer with the esophageal wall was successfully improved in all the patients, which resulted in improvement of the signal-to-noise ratio in both two-dimensional and Doppler echocardiography. The appropriate filling volume of water was within 5 ml to avoid compression of the left pulmonary vein and to avoid the artifact of multiple reflection.

Systemic venous flow during cardiac surgery examined by intraoperative transesophageal echocardiography

Patterns of systemic venous return change after cardiac surgery. However, the exact timing and underlying mechanisms are not well understood. To analyze these changes transesophageal echocardiography was used to evaluate 21 patients (mean age 56 +/- 17 years) during cardiac surgery. Eleven patients underwent coronary bypass grafting, 2 had ablation of accessory bundles, 4 had mitral and 4 had aortic valve replacements. All were in sinus rhythm and were undergoing their first cardiac operation. Hepatic and pulmonary venous flow, tricuspid annular motion, and signs of tricuspid regurgitation were recorded sequentially 5 times: (A) with chest closed, (B) with chest open and pericardium closed, (C) with both chest and pericardium open, (D) after cardiopulmonary bypass with chest open, and (E) after cardiopulmonary bypass with chest closed. The hepatic venous Doppler flow velocity integrals (cm) changed, from stage A to stage E: systolic flow decreased from 5.9 +/- 5.2 to 2.2 +/- 1.4 (p less than 0.01); diastolic flow increased from 3.1 +/- 1.5 to 4.8 +/- 3.3 (p less than 0.001); and systolic to diastolic ratio decreased from 2.0 +/- 1.2 to 0.7 +/- 0.6 (p less than 0.001). Reversed flow at the end of ventricular systole was present in 9 patients (43%) at stage A and in all patients at stage E. Decreased tricuspid annular motion was noted in all but 1 patient after cardiopulmonary bypass. No patient presented significant tricuspid regurgitation at any stage. In conclusion, the significant change in the pattern of systemic venous return after open heart surgery is not due to opening of the chest wall or parietal pericardium, or to tricuspid regurgitation.(ABSTRACT TRUNCATED AT 250 WORDS)

Transesophageal Doppler echocardiography of pulmonary venous flow: a new marker of mitral regurgitation severity

Pulmonary venous flow varies with different cardiac conditions. Flow patterns in response to mitral regurgitation have not been well studied, but flows may vary enough to differentiate among different grades of regurgitation. Accordingly, pulmonary venous flow velocities were recorded in 50 consecutive patients referred for outpatient (n = 26) or intraoperative (mitral valve repair; n = 24) echocardiographic examination for mitral regurgitation. Recordings were made of right and left upper pulmonary veins with pulsed wave Doppler transesophageal echocardiography. Mitral regurgitation was graded from 1+ to 4+ by an independent observer using transesophageal color flow mapping. The results of cardiac catheterization performed 5 weeks earlier in 43 of the patients were also graded for mitral regurgitation by an independent observer. Pulmonary venous flow patterns, the presence of reversed systolic flow and peak systolic and diastolic flow velocities were compared with the severity of mitral regurgitation indicated by each technique. Of the 28 patients with 4+ regurgitation by transesophageal color flow mapping, 26 (93%) had reversed systolic flow. The sensitivity of reversed systolic flow in detecting 4+ mitral regurgitation by transesophageal color flow mapping was 93% and the specificity was 100%. The sensitivity and specificity of reversed systolic flow in detecting 4+ mitral regurgitation by cardiac catheterization were 86% and 81%, respectively. Discordant flows were observed in 9 (24%) of 38 patients; the left vein usually showed blunted systolic flow and the right showed reversed systolic flow. In 22 intraoperative patients, there was "normalization" of pulmonary venous systolic flow after mitral valve repair in the postcardiopulmonary bypass study compared with the prebypass study after the mitral regurgitant leak was corrected.(ABSTRACT TRUNCATED AT 250 WORDS)

Intraoperative echocardiography in infants and children with congenital cardiac shunt lesions: transesophageal versus epicardial echocardiography

To determine the utility and limitations of intraoperative transesophageal echocardiography in infants and children with congenital intracardiac shunts, intraoperative transesophageal (n = 50) and epicardial (n = 49) echocardiograms were performed before and after cardiopulmonary bypass in children from 4 days to 16 years old and 3 to 45 kg in body weight. A miniaturized transesophageal probe (6.9 mm maximal diameter) was used in 36 patients weighting less than or equal to 20 kg. Epicardial imaging was performed with a 5 MHz precordial probe. The intraoperative transesophageal echocardiographic findings before and after cardiopulmonary bypass were correct and complete in 94% of patients. Transesophageal echocardiography correctly identified atrial septal defects, most types of ventricular septal defects, anomalous pulmonary veins, atrioventricular septal defects, tetralogy of Fallot, truncus arteriosus and double inlet ventricles. It failed to provide a correct diagnosis in only three patients, all of whom had doubly committed subarterial ventricular septal defects. Epicardial echocardiography identified all cases that had a doubly committed subarterial ventricular septal defect. A correct and complete intraoperative diagnosis was obtained with the use of epicardial imaging in 92% before and after cardiopulmonary bypass, but this technique required interruption of surgery and could not be completed in three patients because of induced arrhythmias and hypotension. These results demonstrated that intraoperative transesophageal echocardiography consistently defined important morphologic, color and pulsed Doppler ultrasound features of most congenital shunt lesions. Lesions that involved the right ventricular outflow tract are sometimes difficult to image with uniplane transesophageal echocardiography. There were no complications in any of the 50 subjects.

Transesophageal biplane echocardiographic imaging: technique, planes, and clinical usefulness

The technique of examination, imaging planes, and the clinical utility of transesophageal biplane echocardiography are described.