Non Invasive assessment of Coronary Flow Velocity reserve with Transthoracic Colour Doppler Echocardiography to predict significant Left Anterior Descending Coronary Artery Stenosis.

Tamilselvan, K (2007) Non Invasive assessment of Coronary Flow Velocity reserve with Transthoracic Colour Doppler Echocardiography to predict significant Left Anterior Descending Coronary Artery Stenosis. Masters thesis, Stanley Medical College, Chennai.

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Abstract

INTRODUCTION : Definite diagnosis of coronary occlusion can be made by coronary angiography (CAG). However, it is an invasive technique and only available in the catheterization laboratory. Patients without anginal symptoms, left ventricular dysfunction or electrocardiographic changes may not be diagnosed until cardiac events occur. If noninvasive detection of total coronary occlusion before CAG becomes possible, it could help in the consideration of further invasive procedures and in the estimation of the results of various interventions. Coronary flow velocity measurements have provided useful clinical and physiologic information. They have been assessed by several Doppler techniques with a Doppler catheter, a Doppler guidewire , an epicardial probe and a transesophageal probe . Doppler catheter and a Doppler guidewire are already have been validated for the measurement of Coronary flow velocity and established as useful techniques in the clinical setting. However, they are invasive.. Transesophageal Doppler echocardiography is semiinvasive,. Thus, it has been difficult to apply assessment of CFV to patients in routine clinical practice. Transthoracic Doppler echocardiography is noninvasive, relatively inexpensive and widely used in the clinical setting, and can be used for serial studies in echocardiographic laboratories. Several studies have reported that CFV can be measured by visualizing LAD using transthoracic two-dimensional and Doppler echocardiography with a high-frequency transducer . It has been also shown that CFV in the distal LAD can be measured at high success rate by TTDE under the guidance of color Doppler flow mapping, and assessment of CFVR in the LAD by this noninvasive technique is useful in the diagnosis of significant LAD stenosis . AIM ; To determine whether the coronary flow velocity pattern assessed by Transthoracic Colour Doppler Echocardiography serves as a predictor of significant Left Anterior Descending coronary artery stenosis. To evaluate the value of coronary flow velocity reserve determined by Transthoracic Colour Doppler Echocardiography for the assessment the degree of severity of Left Anterior Descending coronary artery stenosis. To compare coronary flow velocity pattern assessed by Transthoracic Colour Doppler Echocardiography and Exercise stress testing with Treadmill to predict significant Left Anterior Descending coronary artery stenosis. CONCLUSIONS : 1. In the present study, the success rate of the measurement of coronary flow velocity in the LAD for the assessment of CFVR was over 79% of patients. 2. Both Peak and Mean diastolic velocity based CFVR <2 correlated well with angiographic evidence of significant stenosis in LAD. 3. A CFVR (PDV) < 2.0 had a sensitivity of 95%, a specificity of 86%, positive predictive value of 92%, and a negative predictive value of 90% for the presence of significant LAD stenosis in this study. 4. CFVR<2 has statistically significant better correlation with angiographic evidence of significant stenosis in LAD in comparison with TMT positivity. 5. This study shows that CFVR correlates well with the angiographic degree of the stenosis. CFVR <1 has significant correlation to predict very severe LAD stenosis. 6. It is shown in our study that Peak SystolicVelocity >5 cm did not correlate with the presence of critical LAD Stenosis. .The hyperemic PDV/PSV ratio has statistical significance to predict LAD lesion in our study, while basal ratio did not. 8.TTCDE assessment of CFVR is safe. No complications observed in our study. 9. Reverse diastolic flow at rest, reflecting retrograde filling of the artery by collaterals, is a very specific marker of coronary occlusion but it unfortunately has a low sensitivity.

Item Type: Thesis (Masters)
Uncontrolled Keywords: Non Invasive assessment ; Coronary Flow Velocity reserve ; Transthoracic Colour Doppler Echocardiography ; Left Anterior ; Descending ; Coronary Artery Stenosis.
Subjects: MEDICAL > Cardiology
Depositing User: Kambaraman B
Date Deposited: 06 Jul 2017 01:50
Last Modified: 06 Jul 2017 10:03
URI: http://repository-tnmgrmu.ac.in/id/eprint/1060

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