Flow Jet Area Research Articles

A tissue-silicone integrated simulator for right ventricular pulsatile circulation with severe functional tricuspid regurgitation

There is a great demand for development of a functional tricuspid regurgitation (FTR) model for accelerating development and preclinical study of tricuspid interventional repair devices. This study aimed to develop a severe FTR model by creating a tissue-silicone integrated right ventricular pulsatile circulatory simulator. The simulator incorporates the porcine tricuspid annulus, valve leaflets, chordae tendineae, papillary muscles, and right ventricular wall as one continuous piece of tissue, thereby preserving essential anatomical relationships of the tricuspid valve (TV) complex. We dilated the TV annulus with collagenolytic enzymes under applying stepwise dilation, and successfully achieved a severe FTR model with a regurgitant volume of 45 ± 9 mL/beat and a flow jet area of 15.8 ± 2.3 cm2 (n = 6). Compared to a normal model, the severe FTR model exhibited a larger annular circumference (133.1 ± 8.2 mm vs. 115.7 ± 5.5 mm; p = 0.009) and lower coaptation height (6.6 ± 1.0 mm vs. 17.7 ± 1.3 mm; p = 0.003). Following the De-Vega annular augmentation procedure to the severe FTR model, a significant reduction in regurgitant volume and flow jet area were observed. This severe FTR model may open new avenues for the development and evaluation of transcatheter TV devices.

Optimal Echocardiographic Approach to the Evaluation of Tricuspid Regurgitation.

To summarize the most recent literature on the optimal echocardiographic approach to the evaluation of tricuspid regurgitation (TR). Severe TR is increasingly recognized as an independent adverse prognostic marker. TR severity grading has been mainly based on qualitative and semiquantitative parameters according to the 2017 ASE guidelines, but new data emerging from 3D echocardiography and MRI will likely provide insights into more quantitative measurements of TR severity. The tricuspid valve's anatomy and physiology is complex and unique. TR can be primary or secondary to tricuspid annular dilatation. Commonly used echocardiographic parameters to define severe TR are severe valve lesions, a large color flow jet area, a vena contracta width of ≥ 7cm, a PISA radius of ≥ 0.9cm, a dense and triangular continuous wave Doppler jet shape, and hepatic vein systolic flow reversal. Complementary imaging modalities such as 3D echocardiography and MRI should be utilized if the 2D echocardiographic evaluation is suboptimal.

Longitudinal Trend of Tricuspid Regurgitation Following Left Ventricular Assist Device Implantation

Purpose Although tricuspid regurgitation (TR) following left ventricular assist device (LVAD) implantation is known to be related to unfavorable outcomes, the longitudinal trend of TR during LVAD course remains unknown. The aim of this study is to clarify the longitudinal trend of TR prior to and following LVAD implantation. Methods We retrospectively reviewed patients who received LVAD implantation between 4/2014-8/2018. We evaluated the grade of TR by echocardiography prior to and following LVAD implantation. TR grade was determined based on the color flow jet area. Moderate or severe TR was defined as significant. We compared clinical outcomes of patients with concomitant tricuspid valve (TV) procedure (TVP+) and those without (TVP-). Results Among 199 consecutive patients, 194 patients had at least 2 echocardiographic TR grade assessments. All patients had a test prior to LVAD implantation, and had an average of 6±4 tests after LVAD implantation during a median of 389 (range 8-1540) days of follow-up. Mean age was 57±13 years and 132 patients (68%) were male. 107 (55%) patients were included in TVP+. Prior to LVAD implantation the prevalence of significant TR was higher in TVP+ (51% in TVP+ vs 20% in TVP-, P All-cause mortality and heart failure (HF) readmission-free survival were similar between the groups. In contrast, patients with significant TR in the early period (within 6 months) had lower HF readmission-free survival (at 1 year, 60% in significant TR vs 74% in non-significant TR, P=0.015, Figure 1B). Conclusion Long-term trend of TR and clinical outcomes throughout LVAD course were similar between TVP+ and TVP-. Patients with significant TR had decreased HF-free survival.

Criteria for Mitral Regurgitation Classification were inadequate for Dilated Cardiomyopathy

BackgroundMitral regurgitation (MR) is common in patients with dilated cardiomyopathy (DCM). It is unknown whether the criteria for MR classification are inadequate for patients with DCM. ObjectiveWe aimed to evaluate the agreement among the four most common echocardiographic methods for MR classification. MethodsNinety patients with DCM were included. Functional MR was classified using four echocardiographic methods: color flow jet area (JA), vena contracta (VC), effective regurgitant orifice area (ERO) and regurgitant volume (RV). MR was classified as mild, moderate or important according to the American Society of Echocardiography criteria and by dividing the values into terciles. The Kappa test was used to evaluate whether the methods agreed, and the Pearson correlation coefficient was used to evaluate the correlation between the absolute values of each method. ResultsMR classification according to each method was as follows: JA: 26 mild, 44 moderate, 20 important; VC: 12 mild, 72 moderate, 6 important; ERO: 70 mild, 15 moderate, 5 important; RV: 70 mild, 16 moderate, 4 important. The agreement was poor among methods (kappa = 0.11; p < 0.001). It was observed a strong correlation between the absolute values of each method, ranging from 0.70 to 0.95 (p < 0.01) and the agreement was higher when values were divided into terciles (kappa = 0.44; p < 0.01) ConclusionThe use of conventional echocardiographic criteria for MR classification seems inadequate in patients with DCM. It is necessary to establish new cutoff values for MR classification in these patients.

Tricuspid and Mitral Valve Carcinoid Disease in the Setting of a Patent Foramen Ovale

59-yr-old-woman with an 8-yr history of carci-noid syndrome with hepatic metastasis presentedwith progressive shortness of breath. Transesophagealechocardiographic examination (TEE) revealed severetricuspid regurgitation, tricuspid stenosis, mild mitralstenosis, moderate mitral regurgitation, and a patentforamen ovale (PFO). She was referred for a tricuspidand mitral valve replacement.Intraoperative TEE confirmed the preoperative diag-nosis of mild tricuspid stenosis with leaflet and chordalthickening, severe tricuspid regurgitation by extent ofcolor flow jet area and hepatic vein flow reversal bypulse wave Doppler, severe right atrial and ventricularenlargement Video Clip 1; please see video clips avail-able at www.anesthesia-analgesia.org), mild mitral ste-nosis, and moderate mitral regurgitation with mitralleaflet thickening and posterior leaflet restriction (Figs. 1and 2; Video Clip 1). Agitated saline contrast injectionconfirmed a PFO. Mild pulmonary regurgitation wasalso noted but the aortic valve was uninvolved. Both themitral and tricuspid valves were replaced with pericar-dial bioprosthetic valves, and the PFO was repaired(Video Clip 2). The excised tricuspid valve was diffuselythickened and fibrotic and the mitral valve leafletsappeared white and smooth, consistent with carcinoidvalvular heart disease. The patient’s hospital course wascomplicated by recurrent carcinoid crises occurringwithin the first postoperative day. Her subsequent hos-pital course was uneventful and she was discharged onpostoperative day 10.Carcinoid tumors arise from the gastrointestinaltract. Malignant carcinoid syndrome occurs whenserotonin and other vasoactive substances are releasedfromcarcinoidtumorcellsandresultinoneormoreofa constellation of symptoms which include flushing,hypotension, diarrhea and bronchospasm. More thanhalf of patients with carcinoid syndrome develop carci-noid heart disease as a late complication and it isassociated with progressive disease.

A Simplified, Practical Approach to Assessment of Severity of Mitral Regurgitation by Doppler Color Flow Imaging With Proximal Convergence: Validation With Concomitant Cardiac Catheterization

To compare the proximal convergence method for quantification of mitral regurgitation with findings on concomitant left ventriculography. In 41 patients (22 men and 19 women, 63 +/- 13 years of age), mitral regurgitation was evaluated concomitantly by Doppler color flow jet area, proximal convergence method, and left ventriculography. A simplified measurement of the proximal convergence, consisting of the aliasing radius and velocity of the proximal isosurface (r2 x V), was used. Angiographic grade correlated well with the proximal convergence method (r2 x V) but had poor correlation with the Doppler color flow jet area method. All patients with a proximal convergence flow rate of less than 10 cm3/s had grade 1 or 2 mitral regurgitation, whereas patients with a proximal convergence flow rate of more than 20 cm3/s had grade 3 or 4 mitral regurgitation. The severity of mitral regurgitation was indeterminate in patients with proximal convergence flow rates from 10 to 20 cm3/s. Doppler color flow jet area correlates poorly with angiographic grade of mitral regurgitation. A simplified proximal convergence method is useful for separating grade 3 and 4 from grade 1 and 2 mitral regurgitation in most patients. A group of patients with indeterminate severity of mitral regurgitation remains, however, in whom further assessment is necessary.

Validation of a new doppler-echocardiographic method for quantifying mitral regurgitation

The noninvasive determination of severity of mitral regurgitation (MR) is often of major clinical importance. We performed simultaneous Doppler echocardiography and left ventricular angiography in 24 patients with MR, comparing a new Doppler echocardiographic technique with angiographic criteria for severity of MR. Angiographic severity was measured on a 1+ to 4+ scale, determined by the degree of opacification of the left atrium during left ventricular systole. The echocardiographic examination consisted of color flow imaging and continuous-wave Doppler echocardiography across the mitral valve. The product of the mitral regurgitant color flow jet area and the mitral regurgitant time-velocity integral was obtained, yielding a Doppler-derived regurgitant volume across the mitral valve. Good correlations were demonstrated between the severity of angiographic MR and the Doppler-derived regurgitant volume (r = 0.831; p < 0.005) and between the angiographic severity of MR and the Doppler-determined mitral regurgitant jet diameter (r = 0.833; p < 0.005). We conclude that a new Doppler echocardiographic method for quantitating the severity of MR correlates well with qualitative angiographic grading. Further study is needed to compare this technique with other quantitative Doppler indexes of severity of MR.

A New Doppler-Echo Method to Quantify Regurgitant Volume

An in vitro technique using color flow imaging and continuous wave Doppler was developed to measure the initial regurgitant flow jet diameter and velocity integral to yield the parameters for a volume calculation. Jets were produced by volume-controlled injection through tubes of various diameters (1.3, 1.9, 2.8, and 3.5 mm) to deliver volumes from 1 to 7 ml over 100 to 300 msec at pressures from 40 to 200 mm Hg. One hundred forty-five samples were obtained. Flow jet diameter consistently overestimated tube diameter by 2 mm when injected volume was 1.5 to 7 ml and by 1.5 mm when injected volume was less than 1.5 ml. This offset was stable with various transducers (2.5, 3.5, 5.0 MHz) at normal gain setting (just under noise). Therefore, corrected flow jet diameter (FJD) = FJD - 2 mm, and Doppler volume = corrected flow jet area x velocity integral. A range of injectates from 1.1 to 7 ml generated Doppler volume of 1.0 to 8.2 ml. The relation between Doppler volume (DV) and injected volume (IV) was DV = 1.079 IV - 0.22, r2 = 0.945, p less than 0.01. This relation was not altered by tube diameter. Thus a method combining color flow imaging and continuous wave Doppler provides a reliable and accurate measure of in vitro flow volume.

Sources of variability for doppler color flow mapping of regurgitant jets in an animal model of mitral regurgitation

To determine whether Doppler color flow mapping could be used to quantify changing levels of regurgitant flow and define the technical variables that influence the size of color flow images of regurgitant jets, nine stable hemodynamic states of mitral insufficiency were studied in four open chest sheep with regurgitant orifices of known size. The magnitude of mitral regurgitation was altered by phenylephrine infusion. Several technical variables, including the type of color flow instrument (Irex Aloka 880 versus Toshiba SSH65A), transducer frequency, pulse repetition frequency and gain level, were studied.Significant increases in the color flow area, but not in color jet width measurements, were seen after phenylephrine infusion for each regurgitant orifice. For matched levels of mitral regurgitation, an increase in gain resulted in a 125% increase in color flow area. An increase in the pulse repetition and transducer frequencies resulted in a 36% reduction and a 28% increase in color flow area, respectively. Jet area for matched regurgitant volumes was larger on the Toshiba compared with the Aloka instrument (5.2 ± 3.1 versus 3.2 ± 1.2 CMZ, p < 0.05).Color flow imaging of mitral regurgitant jets is dependent on various technical factors and the magnitude of regurgitation. Once these are standardized for a given patient, the measurement of color flow jet area may provide a means of making serial estimates of the severity of mitral insufficiency.

The curvilinear relationship between aortic regurgitant volumes and color flow jets. Intraoperative two-dimensional Doppler and electromagnetic flowmeter correlation.

The potential usefulness of two-dimensional Doppler to quantitate valvular regurgitation depends on the relationship between the dimensions of the velocity maps and the regurgitant volumes. We previously found a significant linear regression between aortic regurgitant fraction and jet area, but because of a shallow slope, postulated an exponential or curvilinear relationship. A retrospective analysis of intraoperative electromagnetic flowmeter measurements of aortic flow and epicardial color flow maps of regurgitant jets gave us a more direct examination of the relationship over a wider range of lower flows. Regurgitant volume was calculated from reverse aortic flow and was compared to jet length, area (by planimetry) and volume (from Simpson's rule). Both linear and curvilinear regressions were determined. Correlation coefficients were similar but consistently closer to unity with the exponential equations, and data points were more closely distributed along a curved rather than a straight line. Length regressions were flatter and the volume regressions were steeper than the slopes of the area equations. Thus, the relationship of the gradual slope of the color flow jet area to the regurgitant volume is geometrically determined and limits quantitative application.