Color M-Mode Echocardiography for Non-Invasive Assessment of the Intraventricular Pressure in Dogs Before and After Ductus Arteriosus Occlusion: A Retrospective Study

Abstract

BackgroundNovel non-invasive evaluation of the intraventricular pressure differences and gradients (IVPD and IVPG) by color M-mode echocardiography (CMME) is a promising method in diastolic function evaluation. Patent ductus arteriosus (PDA) is a congenital heart defect which is associated with increased preload. The present work provides a clinical trial for the assessment of IVPD and IVPG changes in dogs before and after surgical occlusion of PDA.Materials and MethodsA total of 12 client-owned dogs were enrolled in this study. PDA was confirmed using echocardiography, and all dogs underwent PDA occlusion. Conventional echocardiography and CMME were conducted on each patient on the operation day (Pre-PDA) and 48 h after its occlusion (Post-PDA). The total IVPD and total IVPG, as well as segmental intraventricular pressure (basal, mid-to-apical, mid, and apical) were measured from Euler's equation using specific software (MATLAB). Data were analyzed for variability and for the difference between pre- and post-PDA. The effect of PDA occlusion on the measured variables was calculated using biserial ranked correlation (rc).ResultsThere was a significant reduction in end-diastolic volume, fraction shortening, stroke volume, and mitral inflow velocities (early and late) after PDA closure. CMME was feasible in all dogs, and the CMME indices showed moderate variability, except for the apical segment of IVPD and IVPG. After PDA closure, in comparison with the pre-PDA occlusion, there was a significant reduction in total IVPD (2.285 ± 0.374 vs. 1.748 ± 0.436 mmHg; P = 0.014), basal IVPD (1.177 ± 0.538 vs. 0.696 ± 0.144 mmHg; P = 0.012), total IVPG (1.141 ± 0.246 vs. 0.933 ± 0.208 mmHg; P = 0.032), and basal IVPG (0.578 ± 0.199 vs. 0.377 ± 0.113 mmHg; P = 0.001); meanwhile, mid, mid-to-apical, and apical segments of both IVPD and IVPG showed non-significant difference. The magnitude of PDA occlusion on the measured variables was clinically relevant and associated with a large effect size on total and basal IVPD and IVPG (rc > 0.6).ConclusionThe current clinical study revealed matched response of IVPD and IVPG to the reduced preload rather than left ventricular relaxation. This result is an initial step in the clinical utility of CMME-derived IVPD and IVPG measurements in the diastolic function evaluation in dogs with PDA that warrants further clinical studies.

Effect of trehalose on heart functions in rats model after myocardial infarction: assessment of novel intraventricular pressure and heart rate variability

“…Our results demonstrated varying significant correlations and regressions among the IVPG, HRV, and conventional echocardiographic parameters. Specifically, our findings regarding IVPG were consistent with previously reported results in rats, dogs, and goats ( 33 , 98 , 99 ), which also showed varying correlations between heart function parameters and IVPG variables. Furthermore, we observed a significant correlation and regression between HRV measurement and heart function parameters ( 100 , 101 ).…”

Novel color M-mode echocardiography for non-invasive assessment of the intraventricular pressure in goats: Feasibility, repeatability, and the effect of sedation

“…These results are quite reasonable particularly when we consider that these data were calculated before sedation. The higher CV of apical indices may be related to variation in the color resolution of the apical part of CMME images compared with the basal and mid parts ( 7 ). Therefore, CMME can be used for further evaluation of heart function in goats and the apical variables should be considered with caution.…”

“…After CMME image acquisition, the IVPD was calculated using in-house code written in MATLAB (The MathWorks, Natick, MA, USA). In each goat, by using the conventional echocardiography images and the displayed ECG, the time from aortic opening to aortic closure (aortic flow images) and the time from Q wave on ECG to the start of mitral valve opening as well as the time from Q wave to peak mitral inflow (mitral inflow images) were obtained and manually inserted into the software during each photo processing by MATLAB ( 7 ). Automatic and manual correction of the resulting curves using specific software codes was applied when required to enhance the quality of analysis.…”

“…Recently, the benefit of spatiotemporal maps of the LV hemodynamics has been applied in the context of diastolic function assessment. The velocity pattern along the transmitral scanline can be efficiently evaluated from the analysis of color M-mode echocardiographic (CMME) recordings after processing of images ( 6 , 7 ) depending principally on Euler's equation ( 8 ). By this method, the LV is divided into basal, mid, and apical parts.…”

“…Experimental studies revealed that IVPG/IVPD segments could determine the changes in heart function in response to loading states ( 16 ), chemotherapy-induced cardiomyopathy ( 1 ), LV ventricular hypertrophy ( 17 ) in addition to uremic and diabetic cardiomyopathies in animal models ( 18 – 20 ). Other clinical studies were explored IVPD/IVPG in healthy dogs and cats ( 21 , 22 ), as well as in dogs with patent ductus arteriosus ( 7 , 21 , 22 ).…”