Defining Coronary Flow Patterns: Comprehensive Automation of Transthoracic Doppler Coronary Blood Flow

Abstract

The coronary microcirculation (CM) plays a critical role in the regulation of blood flow and nutrient exchange to support the viability of the heart. In many disease states, the CM becomes structurally and functionally impaired, and transthoracic Doppler echocardiography can be used as a non-invasive surrogate to assess CM disease. Analysis of Doppler echocardiography is prone to user bias and can be laborious, especially if additional parameters are collected. We hypothesized that we could develop a MATLAB algorithm to automatically analyze clinically-relevant and non-traditional parameters from murine PW Doppler coronary flow patterns that would reduce intra- and inter-operator bias, and analysis time. Our results show a significant reduction in intra- and inter-observer variability as well as a 30 fold decrease in analysis time with the automated program vs. manual analysis. Finally, we demonstrated good agreement between automated and manual analysis for clinically-relevant parameters under baseline and hyperemic conditions. Resulting coronary flow velocity reserve calculations were also found to be in good agreement. We present a MATLAB algorithm that is user friendly and robust in defining and measuring Doppler coronary flow pattern parameters for more efficient and potentially more insightful analysis assessed via Doppler echocardiography.

Improvement of automated analysis of coronary Doppler echocardiograms

“…The early identification of CMD has the potential to allow for the early identification and potential prevention of more serious heart problems such as myocardial ischemia, atherosclerosis, and heart failure. TTDE is an effective and non-invasive method used to assess coronary flow by observing coronary flow patterns, and automatic analysis of coronary blood flow was demonstrated in a previous study by this laboratory to reduce the time required for analysis and the bias typical of manually-analyzed TTDE files 9 . Here, we present improvements to the original program.…”

“…Finally, the program extracted the following parameters from each cardiac cycle: peak velocity, diastolic velocity, decay velocity, systolic rise time, diastolic rise time, diastolic decay time, systolic slope, diastolic slope, decay slope, heart rate, and velocity time integral. These were the same parameters extracted in the original MATLAB program 9 . All parameters were output to a Microsoft Excel file in .xlsx format.…”

“…When analyzing 98 baseline files and 117 hyperemic files both manually and with the automatic program, linear regression analysis showed significantly reduced variability when using automatic analysis, and the time to analyze videos was reduced from 1500 to 50 min. However, agreement between manual and automatic parameter output ranged from less than 1% difference to over 55% difference for certain variables 9 . While the accuracy of the simple regression model is comparable to human evaluators, the parameter variability suggested that with continued testing and program adjustments, automatic analysis of TTDEs could become increasingly more accurate and capable of processing challenging videos.…”

“…However, manual analysis of TTDE CBF can be time consuming and subject to both intra-rater and inter-rater bias 8 . To resolve these issues, our groups began developing a MATLAB program to automatically extract data values from coronary flow patterns of TTDE video files 9 .…”

Prospective Assessment of Coronary Artery Flows Before and After Cardiopulmonary Bypass in Children With a Spectrum of Congenital Heart Disease

“…"Normal" baseline flow velocities in the left coronary artery are generally accepted between 30 and 60 cm/s depending on the age of the patient, either invasively, or by echocardiography. [6][7][8][9][10] Studies have shown that coronary artery velocities in children decrease with age and heart rate 11 and that coronary flow velocities in infants and children are higher than those in adults. 12 Interestingly, in neonates, coronary velocities show a linear increase with age and left ventricular (LV) mass.…”