The role of intraoperative echocardiography in valve surgery

Intraoperative echocardiography in valvular heart disease: an evidence-based appraisal

Intraoperative (IO) transesophageal echocardiography (TEE) is widely used for assessing the results of valvular heart disease (VHD) surgery. Epiaortic ultrasonography (EAU) has been recommended for prevention of perioperative strokes. To what extent does high-quality evidence justify the widespread use of these imaging modalities? In March 2009, we searched MEDLINE (PubMed and OVID interfaces) and EMBASE for studies published in English using database-specific controlled vocabulary describing the concepts of IOTEE, cardiac surgery, VHD, and EAU. We found no randomized trials or studies with control groups assessing the impact of IOTEE in VHD surgery. Pooled analysis of 8 observational studies including 15,540 patients showed an average incidence of 11% for prebypass surgical changes and 4% for second pump runs, suggesting that patients undergoing VHD surgery may benefit significantly from IOTEE, particularly from postcardiopulmonary bypass IOTEE in aortic repair and mitral repair and replacement, but less so in isolated aortic replacement. Further available indirect evidence was satisfactory in the test accuracy and surgical quality control aspects, with low complication rates for IOTEE. The data supporting EAU included 12,687 patients in 2 prospective randomized studies and 4 nonrandomized, controlled studies, producing inconsistent outcome-related results. Despite low-quality scientific evidence supporting IOTEE in VHD surgery, we conclude that indirect evidence supporting its use is satisfactory and suggests that IOTEE may offer considerable benefit in valvular repairs and mitral replacements. The value of IOTEE in isolated aortic valve replacement remains less clear. Evidence supporting EAU is scientifically more robust but conflicting. These findings have important clinical policy and research implications.

Noninvasive imaging of the heart and coronary arteries

There are multiple imaging modalities currently available to noninvasively evaluate the heart and coronary arteries. Choosing the most appropriate modality depends on the pertinent clinical question and the underlying patient characteristics. This article provides an overview of the fields of echocardiography, myocardial perfusion imaging, cardiac computed tomography, and cardiac magnetic resonance imaging, with particular attention to specific clinical applications for cardiac surgery patients.

Interrogation of the aortic valve

OBJECTIVE

To review the essential elements of the transesophageal echocardiographic examination of the aortic valve, with emphasis on the technique for performing a two-dimensional examination, the quantification of aortic stenosis and regurgitation, and the effect of this modality on cardiac surgical decision making.

DESIGN

Literature review.

DISCUSSION

Transesophageal echocardiographic examination of the aortic valve can provide detailed information on aortic valve structure and function, provided proper technique is utilized. This review presents the current recommendations from the American Society of Echocardiography for the performance of a two-dimensional examination of the aortic valve and for the quantification of aortic stenosis or aortic regurgitation by application of Doppler techniques. To demonstrate the applicability of transesophageal echocardiography in clinical practice, the effect of transesophageal echocardiography on the cardiac surgical management of patients with aortic valvular disease is described.

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.

An unusual cause of left ventricular outflow tract obstruction after mitral valve repair

Left ventricular outflow tract (LVOT) obstruction caused by systolic anterior motion is a cause of failed mitral valve repair. Intraoperative transesophageal echocardiography has been very helpful in diagnosing problems with mitral valve repairs intraoperatively, allowing immediate correction. We report an unusual cause of LVOT obstruction attributed to prolapse of the annuloplasty ring into the LVOT. Intraoperative hemodynamics were normal, and the diagnosis would not have been made before leaving the operative suite without the transesophageal echocardiography.

Newer concepts in the surgical treatment of valvular heart disease

The search for the ideal therapy for valve replacement continues. The major options include mechanical or tissue valves, with an increasing variety of tissue valves becoming available. The key factor continues to be thrombogenicity versus durability. Aortic valve surgery primarily consists of replacement. This is aided by the increased variety of options allowing tailoring of the procedure to the patient's native valve disease. Mitral valve surgery has greater potential for repair, which affords preservation of the native valve, optimizing function and reducing long-term complications. An increasingly popular concept is treatment of secondary or functional mitral valve regurgitation in the setting of depressed left ventricular function. The routine use of intraoperative transesophageal echocardiography and a trend toward the use of minimally invasive procedures are altering the conduct of valve operations.

Arrested paradoxical emboli in transit diagnosed by intraoperative transesophageal echocardiography

IMPLICATIONS

We describe a patient who developed a deep venous thrombosis that subsequently embolized to both the pulmonary and systemic arterial circulations. The diagnosis of arrested paradoxical embolus in transit at two separate and unique anatomic locations was made with intraoperative transesophageal echocardiography, and the patient did not suffer organ damage as a result of the paradoxical emboli.

Intraoperative transesophageal echocardiographic assessment of the effect of protamine on paraprosthetic aortic insufficiency immediately after stentless tissue aortic valve replacement

Mild paravalvular aortic insufficiency (AI) is common immediately after stentless bioprosthetic aortic valve replacement. Although resolution of paraprosthetic jets with protamine has been described, the predictability of resolution has not been addressed. Intraoperative transesophageal echocardiography was performed before and after protamine administration among 2 groups. The first group (n = 20) was used to define the prevalence and severity of paravalvular AI after stentless tissue AVR, and define a threshold value for jet size associated with resolution with protamine. A second group (n = 18) was used to prospectively test the determined threshold. Paravalvular AI occurred in 13 of 20 (65%) patients. Using a threshold value of 0.3 cm or less jet width, prospective testing revealed positive and negative predictive values for AI resolution with protamine of 93% (14 of 15) and 100% (3 of 3), respectively. Protamine administration is associated with resolution of small AI jets immediately after implantation of a stentless aortic bioprosthesis, with a jet width 0.3 cm or less strongly predictive of resolution.

Prosthetic valve malfunction masked by intraoperative pressure measurements

IMPLICATIONS

We describe a case in which intraoperative echocardiography recorded an abnormally high pressure gradient across a newly implanted mechanical heart valve. However, inserting pressure-transducing needles on each side of this prosthesis did not confirm the echocardiographic findings. The prosthesis was later confirmed to be malfunctioning and was replaced.

Impact of intraoperative transesophageal echocardiography among patients undergoing aortic valve replacement for aortic stenosis

In this study, we sought to define the impact of intraoperative transesophageal echocardiography (IOTEE) among patients undergoing aortic valve replacement for severe aortic stenosis. We reviewed the clinical data and preoperative, intraoperative, and postoperative echocardiograms of all adults who underwent aortic valve replacement for aortic stenosis and had IOTEE between January 1993 and December 1996. There were 383 patients (223 men, 160 women; mean age, 69 years). Fifty-four (14%) of the 383 patients had mitral valve surgery at the time of aortic valve replacement. In 6 patients, mitral valve surgery was not planned but was added because of findings on IOTEE. In 25 patients, mitral valve surgery was canceled on the basis of the IOTEE. Additional information was found by IOTEE in 25 patients before and after bypass, altering the surgical plan in 18 of these 25 patients. Overall, IOTEE altered the planned operation in 49 (13%) of the 383 patients. These data support the routine use of IOTEE among patients undergoing aortic valve replacement for aortic stenosis.

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.