Introduction:
Echocardiography is the key tool for the diagnosis and evaluation of aortic regurgitation, and is the primary non-invasive imaging method for AR assessment. Diagnostic cardiac catheterization is no longer recommended except in rare cases when echocardiography is non-diagnostic or discrepant with clinical data. The aortic valve and root can be evaluated by transthoracic (TTE) or transesophageal echocardiography (TEE). However TEE is generally superior to TTE imaging because of the improved resolution of higher frequency TEE probe. Anatomic evaluation of the aortic valve is based on a combination of short- and long-axis images to identify the number of leaflets, and to describe leaflet mobility, thickness, and calcification. In addition, the combination of imaging and Doppler allows the determination of the level of obstruction; subvalvular, valvular, or supravalvular. Transthoracic imaging usually is adequate, although transesophageal echocardiography (TEE) may be helpful when image quality is suboptimal. The primary haemodynamic parameters recommended for clinical evaluation of AR severity are: -Regurgitant volume -Regurgitant fraction -Effective regurgitant orifice area - Vena contracts width -Diastolic reversal of flow in descending aorta.
PURPOSE OF STUDY- We want to assess compare preoperative trans thoracic echocardiography findings with trans esophageal findings and determine which parameters are reliable in detecting the severity of AR. The effect of anaesthesia drugs may cause changes in haemodynamics which can studied in detail using TEE. Hence, we thought it worthwhile to study the valve and comparatively evaluate it with preoperative TTE.
Aims and objectives - To study the aortic valve apparatus (valve area, valve type, presence of calcification or vegetation and gradients across the valve) and compare it with preoperative transthoracic echocardiography findings. Inclusion Criteria - ASA II and III patients of either sex posted for aortic valve replacement for severe AR without left ventricular dysfunction Exclusion Criteria - < 18 years patients - ASA IV and above patients. - Midline Redo Surgeries - Patients with contraindications to TEE probe insertion. - Patients with moderate to severe mitral pathology or aortic stenosis.
Materials and Methods: Study area and population: Patients admitted in the in-patient department of Cardiovascular and thoracic Surgery at KEM Hospital and posted for elective aortic valve replacement requiring TEE evaluation intraoperatively. Study Design: Prospective observational study. Duration of the study: 6 months. Place of the study: Seth GS Medical College and KEM Hospital, Mumbai. Sample size: 40 patients posted for aortic valve replacement over the 6 months period. (The sample size is selected based on the time duration of the study. As we have limited time duration to complete the study, we have selected 40 as the minimum sample size) Methodology: After local ethical committee approval and written informed consent, 40 patients undergoing elective aortic valve replacement will be enrolled for the study. Pre anaesthesia evaluation will be conducted on a day prior to the study and a detailed history and present complaints will be noted. Detailed general and systemic examination of the cardiovascular and respiratory system will be done. Routine laboratory investigations will be done. Pre operative transthoracic echocardiographic findings will be noted. All patients will be kept fasting for 8 hours prior to surgery. On the day of surgery, the patient will be wheeled into the operating room and after securing intravenous line, standardized monitors will be applied. Right internal jugular vein and radial artery will be cannulated under local infiltration anaesthesia. Standardized general anaesthesia will be administered to the patients. With direct laryngoscopy TEE probe will be inserted and aortic valve will be studied in the following views - 1) Mid esophageal 4 chamber view - 2) Mid esophageal LVOT long axis(LAX) view - 3) Mid esophageal aortic valve short axis(SAX) view - 4) Mid esophageal aortic valve LAX view - 5) Transgastric LAX view - 6) Deep Transgastric view After completing the brief TEE examination of the aortic valve, the findings will be noted and the results will be analysed. Statistical Analysis After data collection data entry will be done in Excel sheet and data analysis will be done with the help of statistical software (SPSS version 24.0). Quantitative data like valve area and gradients will be presented with the help of mean, std deviation, median, IQR (Inter Quartile Range). Qualatitative data like valve morphology, type, severity and any findings in aorta will be presented with the help of frequency and percentage tables, association among the various study parameters will be assessed with Chi – Square test. P value <0.05 will be taken as level of significance.
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