Transesophageal Echocardiography

Transesophageal Echocardiography: A primer Dr Chandana Samaranayake CMS 2004-02-11 Transesophageal Echo Exam • Indications: –Examination of distal transverse and descending aorta (suspected coarctation, PDA, atherosclerosis, aneurism, dissection) –Examination of atria (thrombi, ASD) –Difficulty in obtaining transthoracic images –Intra-operative TEE monitoring CMS Chandana Samaranayake 2004-02-11 CS-US0402-1 TEE - a primer Equipment For TEE Lab • • • • • • • Ultrasound system with TEE probe Lignocaine nasal/oral spray Lignocaine gel Ultrasound coupling gel Disposible TEE sheath Bite guard Vital signs monitor or SpO2 monitor • Emergency resuscitation cart with: –defibrillator –Intubation equipment –Oxygen • Suction unit CMS Chandana Samaranayake 2004-02-11 CS-US0402-1 TEE - a primer Patient Preparation • Patient must fast overnight (for afternoon exams – pt must remain nil orally following breakfast) • For peds and anxious patients, prior sedation is recommended (see sedation) • Consent form must be signed by patient or guardian • Procedure must be explained to patient • Before procedure, verify that the patient has remained nil orally (except for medication) • If contrast studies are to be undertaken, insert IV cannula CMS Chandana Samaranayake 2004-02-11 CS-US0402-1 Transesophageal Echocardiography - a primer Recommended Sedation HYOSCINE HYDROBROMIDE (Scopolamine Hydrobromide) • Indications: motion sickness; premedication • Cautions: elderly, urinary retention, cardiovascular disease, gastro-intestinal obstruction, hepatic or renal impairment; porphyria; pregnancy and breastfeeding; • DRIVING Drowsiness may affect performance of skilled tasks (e.g driving) and may persist for up to 24 hours or longer after removal of patch: effects of alcohol enhanced Contra-indications: closed-angle glaucoma Side-effects: drowsiness, dry mouth, dizziness, blurred vision, difficulty with micturition Dose: by mouth, 300 micrograms with water 60 minutes before procedure; CHILD 4–10 years 75–150 micrograms, over 10 years 150–300 micrograms Source: British National Formulary CMS Chandana Samaranayake 2004-02-11 CS-US0402-1 Transesophageal Echocardiography - a primer Preparation • • • • • • • • • • • • Test ultrasound system to make sure it is functioning properly Check probe – the outer covering must be smooth and undamaged Check probe controls – flex and anteflex probe Perform probe calibration if necessary Spray Lignocaine to the patient’s throat Ask the patient to sit up straight (adult) or lie in left lateral position (peds) Apply small amount of coupling gel to probe head Roll up the sheath over probe – squeeze out any air bubbles that may have formed over probe head Connect vital signs/spO2 monitor to patient Lubricate sheath with Lignocaine gel and enter the probe in to patient’s mouth, holding the probe with thumb and index finger of the right hand, with the probe head facing down towards the patient’s tongue Place bite guard Slide the probe down the patient’s throat in a single rapid movement CMS Chandana Samaranayake 2004-02-11 CS-US0402-1 TEE - a primer Imaging Axes The three primary axes of imaging consist of basal short axis (uppermost), long axis (middle) and transgastric short axis (lower) CMS Chandana Samaranayake 2004-02-11 CS-US0402-1 TEE - a primer Orientation • The transducer scanning sector is fan-shaped • The narrow portion of the fan lies closest to the transducer • Therefore, this segment represents posterior area of the heart (ie area closest to the esophagus) • The wide portion of the fan represents anterior aspects of the image • Finally, patient left corresponds to observer right and vice versa CMS Chandana Samaranayake 2004-02-11 CS-US0402-1 Posterior (dorsal) Patient’s right Patient’s left Anterior (ventral) TEE - a primer Basic TEE Examination Sequence Step                             View    1               Distal aortic arch and descending thoracic/upper                     abdominal aorta    2               Basal short axis scan of great vessels    3               Basal short axis scan of aortic valve     4               Long axis scan of left ventricular outflow tract    5               Long axis scan of mitral valve and left ventricle    6               Basal short axis scan of left atrial appendage    7               Imaging of inter-atrial septum    8               Long axis scan of tricuspid valve and right ventricle                     at level of anterior mitral leaflet    9               Long axis scan of tricuspid valve and right ventricle                     at level of coronary sinus   10              Transgastric short axis mid-chamber scan of right                     and left ventricles CMS Chandana Samaranayake 2004-02-11 CS-US0402-1 TEE - a primer 10 Step - Distal aortic arch and descending thoracic/upper abdominal aorta The transverse aorta appears as a linear structure The proximal portion cannot be visualized because the air-filled trachea acts as a barrier to ultrasound Moving further down, the descending aorta appears as a concentric structure Transverse aorta Descending aorta Irregularities of the intima represent plaque formation CMS Chandana Samaranayake 2004-02-11 CS-US0402-1 TEE - a primer 11 Step - Basal short axis scan of great vessels The cross-section is such that the aorta (Ao) and superior vena cava (SVC) are concentric.  The normal disproportion between the Ao and SVC dimensions should also be noted The Ao lies anterior to the bifurcation of the main pulmonary artery The SVC lies directly anterior to the right pulmonary artery (RPA) The left pulmonary artery (LPA) cannot usually be imaged beyond its origin CMS Chandana Samaranayake 2004-02-11 CS-US0402-1 TEE - a primer 12 Step - Basal short axis scan of aortic valve As illustrated below, the right atrial (RA) area is normally less than that of the left atrium (LA) at the level of this cross-section Note that the aortic valve (AV) and right ventricular outflow tract (RVOT) lie at the same level, the pulmonic valve (PV) being superior to both structures CMS Chandana Samaranayake 2004-02-11 CS-US0402-1 TEE - a primer 13 Step – Long axis scan of left ventricular outflow tract Landmark structures include the aortic valve (AV), with its characteristic “Mercedes-Benz” emblem morphology, and the anterior leaflet of the mitral valve (AML) CMS Chandana Samaranayake 2004-02-11 CS-US0402-1 TEE - a primer 14 Step – Long axis scan of mitral valve and left ventricle As illustrated below, the anterior mitral leaflet (AML) is normally disproportionately longer than the posterior leaflet (PML) The true apex of the left ventricle may not be visualized CMS Chandana Samaranayake 2004-02-11 CS-US0402-1 TEE - a primer 15 Step – Basal short axis scan of left atrial appendage The left upper pulmonary vein (LUPV) lies posterior to the left atrial appendage (LAA) and anterior to the descending thoracic aorta (Ao) CMS Chandana Samaranayake 2004-02-11 CS-US0402-1 TEE - a primer 16 Step – Imaging of the inter-atrial septum The inter-atrial septum should be carefully examined visually If ASD is suspected but not visualized, a contrast study should be conducted using intravenously administered agitated saline In the illustration below, a right to left shunt is evidenced by the presence of saline in the left atrium CMS Chandana Samaranayake 2004-02-11 CS-US0402-1 TEE - a primer 17 Step – Long axis scan of tricuspid valve and right ventricle at level of anterior mitral leaflet As illustrated below, the normal tricuspid valve (TV) is usually not visualized in its entirety CMS Chandana Samaranayake 2004-02-11 CS-US0402-1 TEE - a primer 18 Step – Long axis scan of tricuspid valve and right ventricle at level of coronary sinus The orifice of the coronary sinus lies proximal to the septal leaflet of the tricuspid valve (TV) CMS Chandana Samaranayake 2004-02-11 CS-US0402-1 TEE - a primer 19 Step 10 – Long axis scan of tricuspid valve and right ventricle at level of coronary sinus This standard view represents a mid-papillary muscle level cross-section Asymmetry of the papillary muscles usually indicates an improper oblique section CMS Chandana Samaranayake 2004-02-11 CS-US0402-1 TEE - a primer 20 Evaluation of left ventricular wall motion 1.  The transgastric short axis image is divided into four segments 2.  The motion of each of the segments is graded as follows; 0=normal; 1=hypokinetic; 2=dyskinetic; 3=akinetic CMS Chandana Samaranayake 2004-02-11 CS-US0402-1 TEE - a primer 21 Interesting articles… http://www.thedoctorslounge.net/cardiolounge/articles/tee/techniques htm - TEE techniques http://www.siuh.edu/pediatrics/articles/doc3.html - TEE in congenital heart disease http://www.hcs.gr/periodiko/pdf/Supplement%2041/A55-A58.pdf Clinical case: traumatic dissection of the aorta http://www.postgradmed.com/issues/1999/10_01_99/lopez.htm Evaluation of the aorta using TEE CMS Chandana Samaranayake 2004-02-11 CS-US0402-1 TEE - a primer 22 ... are to be undertaken, insert IV cannula CMS Chandana Samaranayake 2004-02-11 CS-US0402-1 Transesophageal Echocardiography - a primer Recommended Sedation HYOSCINE HYDROBROMIDE (Scopolamine Hydrobromide)... 150–300 micrograms Source: British National Formulary CMS Chandana Samaranayake 2004-02-11 CS-US0402-1 Transesophageal Echocardiography - a primer Preparation • • • • • • • • • • • • Test ultrasound system to.. .Transesophageal Echo Exam • Indications: –Examination of distal transverse and descending aorta