DK2985_C000 1..28 - AlSharqia Echo Club

Indications for Perioperative TEE 561authors recommended TEE monitoring for all septalmyectomies for HOCM.The 1996 ASA/ASC task force believed that the echocardiographicconfirmation of the adequacy of HOCM surgeryimproves clinical outcomes based, in part, on naturalhistory data suggesting poorer outcomes for patients withpersistent hemodynamic compromise from HOCM (12).The ACC/AHA/ASE 2003 echocardiography practiceguidelines consider TEE monitoring for surgical repair ofHOCM as a category I indication.F. EndocarditisIntraoperative use of TEE for endocarditis is a category Iindication when preoperative testing is inadequate or extensionof infection to perivalvular tissue is suspected (12).Although its accuracy in detecting endocarditis outsidethe OR is well established, there is little evidence beyondcase reports that the use of intraoperative TEE is moreaccurate in detecting endocarditis or improves clinical outcomes(12). Before the patient enters the OR, either thetransthoracic echocardiography (TTE) or the TEE shouldbe performed to help plan the surgery and avoid unexpectedintraoperative findings.Beyond the accepted applications of intraoperativeTEE during valve surgery, there is little role for TEE inevaluating endocarditis during surgery, unless preoperativetesting was inadequate, extension to perivalvulartissue is suspected or the patient required urgent surgery.Noncardiac surgery in patients with uncomplicated endocarditisis a category III indication for intraoperative TEE.The complications of infective endocarditis, includingabscess formation (see Chapter 15, Fig. 15.31), leafletdiverticula, leaflet perforation, fistula tracts, and pseudoaneurysmformation are better detected by TEE than TTE.Regarding abscess formation, the specificity of both techniquesexceeds 90%. The sensitivity regarding abscesscavity was 28% for TTE and 87% for TEE.Transesophageal echocardiography is especially effectivewith prosthetic mitral valves, as acoustic shadowinghinders visualization of the atrial aspect by TTE. ThereforeTEE must be combined with TTE but may evensupplant TTE in patients with valve prosthesis whopresent with signs and symptoms of endocarditis.G. Unstable ICU Patients with UnexplainedHemodynamic Disturbances, SuspectedValve Disease, or ThromboembolicProblemsUnexplained hemodynamic disturbances, suspected valvedisease, or thromboembolic problems in unstable ICUpatients is a category I indication for TEE if the other testsor monitoring techniques have failed to confirm the diagnosisor if patients are too unstable to undergo other tests.In this setting, TEE can provide essential informationthat alters patient management of myocardial function,valve function, and volume status, which is critical in evaluatingthe patient with unexplained hypotension or unexplainedpulmonary edema.Some studies have reported that TEE detected informationnot seen by TTE in 44–59% of ICU patients. Informationprovided by TEE examinations is reported tochange therapy in 17–48% of critical care patients (17).The TTE images obtained in the ICU can be inadequatebecause of poor acoustic penetration, limited windowsfrom surgical bandages and drains, mechanical ventilation,and an inability to position patients properly. Recent technologicaladvances such as harmonic imaging and contrastimaging have improved TTE image quality significantlyand decreased the number of nondiagnostic studies. Inurgent situations and in acutely unstable patients, TEEmay nevertheless remain a first option. The presence ofmassive or proximal pulmonary emboli can be diagnosedby TEE (see Chapter 9, Fig. 9.40). Potential complicationsof myocardial infarction, including left ventricular dysfunction,papillary muscle rupture with severe MR (seeChapter 8, Fig. 8.20) and myocardial rupture (free wallor ventricular septum), may be identified. TEE can alsodetect right-to-left intracardiac shunting through a patentforamen ovale, which may occur in ventilated patientsrequiring high levels of pressure support and right ventriculardysfunction.H. Pericardial Window ProceduresIntraoperative evaluation of pericardial window proceduresis a category I indication for perioperative TEE.There is some evidence suggesting that perioperativeTEE is more sensitive than TTE in detecting pericardialeffusions (mostly loculated effusions), but there is littleevidence beyond case reports that such findings, duringor after surgery, result in improved clinical outcomes.Perioperative TEE is clinically beneficial if it detects pericardialtamponade and avoids serious hemodynamicsequelae. This application is important when effusionscannot be detected easily by other means such as TTE(see Chapter 11, Fig. 11.9). Clinical experience suggeststhat posterior or loculated pericardial effusions that areeasily missed by the surgeon may develop in the patientstreated with pericardial windows.I. Evaluation of Complex ValveReplacements Requiring Homograftsor Coronary Reimplantation such asthe Ross ProcedureIn this context, TEE is a category I indication and is usefulto evaluate valve function and ventricular function beforesurgery and it may also modify the surgical approach.