Assessment of Surgical Results

After the planned surgical intervention, TEE can identify residual defects that need to be addressed to limit morbidity, mortality, and hospitalization costs. In a study of 50 patients, TEE identified 2 patients in whom new SWMAs provided the only sign of unsuspected graft occlusion and prompted graft thrombectomy.^[102] In another study of 82 high-risk patients, Savage and coworkers used staged blinding of the cardiac surgeons and anesthesiologists at critical points during surgery. ^[103] After these clinicians documented their planned management at each stage, TEE results were revealed and led to at least one significant change in anesthetic management in 51% of patients and surgical management in 33% of patients, including additional unplanned or revised grafts (15%) and unplanned valve procedures (20%). Similarly, TEE has profoundly affected valvular heart surgery. In a study of 154 patients undergoing valve surgery, intraoperative TEE documented unsatisfactory repairs in 10 patients (6%) requiring immediate further surgery.^[104] Although 6 of these 10 patients had abnormal V waves or elevated pulmonary capillary wedge pressure, hemodynamics was normal in the other 4 patients and only TEE indicated defective repair. At the conclusion of surgery, TEE revealed adequate valvular function in 123 of 154 patients (80%); 18 of these patients (15%) suffered a major postoperative complication, with 6 dying (5%). In contrast, TEE revealed moderate valve dysfunction in seven patients (5%), six of whom suffered major complications (86%), with three dying (50%). Subsequent studies have confirmed that intraoperative TEE assessment of mitral valve function is predictive of postoperative function and outcome.^[105] However, during this assessment, the patient's hemodynamics must be restored to normal values; otherwise, the prognostic value of TEE can be lost. Even with the maturation of valve repair techniques, a significant number of repairs must be immediately revised.^[106] During valve replacement surgery, TEE reliably detects periprosthetic leaks (surprisingly common).^[107] Although moderate or severe periprosthetic leaks should almost always undergo immediate repair, almost half of small leaks resolve with the administration of protamine. ^[108] Even though immediate prosthetic valve malfunction is rare, it can occur and go undetected if TEE is not performed.^{[109] [110]}

TEE can be performed safely in infants as small as 3 kg (see also Chapter 51 ). Ungerleider and associates found that even with extensive experience as congenital heart surgeons, they were unable to predict without intraoperative echocardiography which of their repairs needed immediate revision.^[111] Moreover, when immediate revision was performed, hospital costs were much less than when a second operation was needed to repair the residual defect ($34,000 versus $94,000). Stevenson and coauthors reported that intraoperative TEE reliably detected residual cardiac defects in 17 (7%) of 230 consecutive patients undergoing congenital heart surgery.^[112] However, a subsequent publication from the same center reported that the number of residual defects missed by intraoperative TEE increased from 2% to 13% when TEE was performed by the attending anesthesiologist and not a separate echocardiographer.^[33] Although this study does not resolve the issue of whether a separate echocardiographer is required to adequately perform TEE in patients undergoing congenital heart repairs, it does amply demonstrate that patients can suffer when intraoperative TEE is not expertly performed, interpreted, and acted on. In this study, the deaths of seven patients may have been related to delayed recognition of residual defects.