A simplified method for determining regurgitant fraction by Doppler echocardiography in patients with aortic regurgitation

Practical Echocardiographic Approach of the Regurgitant Mitral Valve Assessment

Mitral regurgitation is the second-most frequent valvular heart disease in Europe after degenerative aortic stenosis. It is associated with significant morbidity and mortality, and its prevalence is expected to increase with population aging. Echocardiography is the first diagnostic approach to assess its severity, constituting a challenging process in which a multimodality evaluation, integrating quantitative, semiquantitative and qualitative methods, as well as a detailed evaluation of the morphology and function of both left ventricle and atria is the key. In this review, we would like to provide a practical diagnosis approach on the mitral valve regurgitation mechanism, severity quantification, and planning of future therapeutic options.

Restrictive filling pattern is associated with increased humoral activation and impaired exercise capacity in dilated cardiomyopathy

OBJECTIVES

Although heart failure (HF) is characterized by increased proinflammatory cytokines, natriuretic peptide levels and impaired exercise capacity, the effect of concomitant diastolic dysfunction on those parameters has not been adequately studied.

METHODS

We analyzed circulating levels of IL-1, IL-6, TNF-alpha and its soluble receptors, sTNFRI and sTNFRII, Nt-ANP and Nt-BNP natriuretic peptides in 81 patients, aged 56+/-12 years, with non-ischemic dilated cardiomyopathy (NIDC), LVEF 29.7+/-7.75% and functional NYHA class II-III. An echocardiographic study and cardiopulmonary exercise test (CPE) were performed in all patients.

RESULTS

Patients were divided into restrictive (24 patients, group I) and non-restrictive (57 patients, group II) groups, according to their transmitral-filling pattern. No differences in LV dimensions or LVEF were found between the two groups. Group I showed increased levels of IL-6 (P=0.006), TNF-alpha (P=0.05), sTNFRII (P=0.02), Nt-ANP (P<0.001) and Nt-BNP (P<0.001) and decreased exercise duration (P<0.001) and PVO(2) (P<0.001) compared to group II. The strongest independent predictors for restrictive filling pattern were Nt-ANP and IL-6 levels, while Nt-BNP levels were the strongest PVO(2) predictor.

CONCLUSIONS

Restrictive filling pattern implying greater diastolic dysfunction may contribute to increased cytokine production in the heart failure syndrome, as well as greater increases in natriuretic peptides and decreased exercise tolerance.

Strategy for optimal aortic regurgitation quantification by Doppler echocardiography: agreement among different methods

BACKGROUND

Although different Doppler methods have been validated for aortic regurgitation quantification, the benefit of combining information from different methods has not been defined.

METHODS

Our study included 2 phases. In the initial phase (60 patients), Doppler parameters (jet width, short-axis jet area, apical jet area, regurgitant fraction from pulmonary and mitral flow, and deceleration slope) were correlated with angiography; range values for each severity grade were defined and intraobserver and interobserver and intermachine variability were studied. In the validation phase (158 patients), defined value ranges were prospectively tested and a strategy based on considering as the definitive severity grade that in which the two best methods agreed was tested.

RESULTS

Jet width had the best correlation with angiography (r = 0.91), and its ratio with the left ventricular outflow diameter did not improve the correlation (r = 0.85) and decreased reproducibility. Apical jet area and regurgitant fraction from pulmonary flow permitted acceptable quantification (r = 0.87 and 0.86, respectively) but with worse reproducibility. The other methods were not assessable in 20% to 30% of studies. Concordance with angiography decreased in jet width when the jet was eccentric (90% vs 77%, P <.01), in apical jet area when mitral valve disease was present (84% vs 65%, P <.02), and in short-axis jet area and regurgitant fraction from pulmonary flow with concomitant aortic stenosis (77% vs 44%, P <.002 and 77% vs 53%, P <.02, respectively). Agreement with angiography was very high (94 [95%] of 99) when severity grade coincided in both jet width and apical jet area. In 59 cases without concordance, regurgitant fraction from pulmonary flow was used as a third method. Overall, this strategy permitted concordance with angiography in 146 patients (92%).

CONCLUSIONS

Jet width is the best predictor in aortic regurgitation quantification by Doppler echocardiography. However, better results were obtained when a strategy based on concordance between jet width and another Doppler method was established, particularly when the jet was eccentric.

Echocardiographic quantitation of mitral regurgitation: a new Doppler technique

Our objective is to develop a new transthoracic Doppler echocardiographic technique to determine mitral regurgitant fraction. The standard color Doppler method for assessment of mitral regurgitation is semiquantitative and dependent on instrument gain. By using the mitral and aortic valve continuous wave Doppler velocities, one can determine regurgitant fraction. This technique takes into account the flow dependence of the mitral valve area. Two constants, A and B, which represent the flow dependence of the mitral valve area and the ratio of the mitral valve area to aortic valve area at zero flow, respectively, were determined by regression in 36 patients without valvular disease (r = .89). Thirty patients with isolated mitral regurgitation were then studied. The mitral regurgitant fraction was calculated from the following: Regurgitant fraction = 1 - TVIav/Bf[Vmv/(1 - AVmv)]dt, where TVIav is the time velocity integral across the aortic valve, Vmv is the continuous wave velocity across the mitral valve, and A and B are constants. The regurgitant fraction was then compared with color Doppler assessment of mitral regurgitation assessed by independent observers. In patients with mitral regurgitation, there was a strong correlation between standard visual assessment and our new Doppler method (Kendall's tau b rank correlation = 0.65; p < .001). The new Doppler method was able to correctly categorize 90% of patients with mild mitral regurgitation and 88% of patients with severe mitral regurgitation; however, there was poorer agreement with the color Doppler assessment of moderate mitral regurgitation. Mitral regurgitant fraction can be calculated with our new Doppler method. This method is quantitative, objective, nongain dependent, and separates mild from severe mitral regurgitation well.

Natural history and left ventricular response in chronic aortic regurgitation

This study was aimed at clarifying the natural history and left ventricular response in aortic regurgitation using M-mode echocardiography. We analyzed the history and echocardiographic data on 94 patients, who were divided into 4 stages according to symptoms. The duration of the asymptomatic period, which represents pure volume overload, is long, and the period of minimal symptoms, combined volume and pressure overload, is relatively short. Patients with overt heart failure due to impaired contractility can survive longer than is usually believed, and the factor that predicted the onset of heart failure was a decrease in fractional shortening > 3.8 percentage points.