The value of assessing pulmonary venous flow velocity for predicting severity of mitral regurgitation: A quantitative assessment integrating left ventricular function

Chronic mild to moderate mitral regurgitation will not have an impact on left atrial strain parameters in the pediatric population

BACKGROUND

Left atrial strain (LAS) analysis represents a newer non-invasive, sensitive and specific technique for assessing left atrial (LA) function and early detection of its deformation and dysfunction. However, its applicability in mitral regurgitation (MR) in pediatric population remains unexplored, raising pertinent questions regarding its potential role in evaluating the severity and progression of the disease.

OBJECTIVE

To investigate the impact of chronic MR in children and adolescents on LA remodeling and function.

METHODS

The study included 100 participants. Patients with primary and secondary chronic MR lasting at least 5 years fit our inclusion criteria. The exclusion criteria from the study were: patients with functional mitral regurgitation due to primary cardiomyopathies, patients with artificial mitral valve, patients with MR who had previously undergone surgery due to obstructive lesions of the left heart (aortic stenosis, coarctation of the aorta), patients with significant atrial rhythm disorders (atrial fibrillation, atrial flutter). The echocardiographic recordings were conducted by two different cardiologists. Outcome data was reported as mean and standard deviation (SD) or median and interquartile range (Q1-Q3).

RESULTS

The study included 100 participants, of whom 50 had MR and the remaining 50 were without MR. The average age of all participants was 15.8 ± 1.2 years, with a gender distribution of 37 males and 63 females. There was a significant difference in the values of LA volume index (LAVI), which were higher in patients with MR (p= 0.0001), S/D ratio (and parameters S and D; p= 0.001, p= 0.0001, p= 0.013), mitral annulus radius (p= 0.0001), E/A ratio (p= 0.0001), as well as septal e' (m/s), lateral e' (m/s), and average E/e' ratio, along with the values of TV peak gradient and LV global longitudinal strain (%). There was no significant difference in LA strain parameters, nor in LA stiffness index (LASI).

CONCLUSION

Our findings revealed significant differences in several echocardiographic parameters in pediatric patients with MR relative to those without MR, providing insight into the multifaceted cardiac structural and functional effects of MR in this vulnerable population.

The Prognostic Value of Pulmonary Venous Flow Reversal in Patients with Significant Degenerative Mitral Regurgitation

Background: The prognostic significance of pulmonary venous (PV) flow reversal in degenerative mitral regurgitation (dMR) is not well-established. Objective: We aimed to assess whether reversed PV flow is associated with adverse outcomes in patients with significant dMR. Methods: We retrospectively analyzed consecutive patients referred to a tertiary center for evaluation of dMR of greater than moderate degree, who had normal sinus rhythm, had a left ventricular ejection fraction of above 60%, and did not suffer from any other major valvular disorders. The primary outcome was the combined rate of all-cause mortality, mitral intervention, or new-onset atrial fibrillation (AF) at 5 years following index echocardiogram. Secondary outcomes included individual components of the primary outcome. Results: Overall, 135 patients (median age 68 (IQR, 58-74) years; 93 (68.9%) males; 89 (65.9%) with severe MR) met the inclusion criteria and were followed for 115.2 (IQR, 60.0-155.0) months. Patients with a reversed PV flow pattern (PVFP) (n = 34) more often presented with severe MR compared to those with a normal (n = 49) and non-reversed PVFP (n = 101) (RR = 2.03 and 1.59, respectively, all p < 0.001). At 5 years, they experienced the highest cumulative incidence of the primary outcome (80.2% vs. 59.2% and 67.3%, p = 0.008 and 0.018, respectively). Furthermore, a reversed PVFP was independently associated with a higher risk of the primary outcome compared to normal PVFP (HR 2.53, 95% CI 1.21-5.31, p = 0.011) and non-reversed PVFP (HR 2.14, 95% CI 1.12-4.10, p = 0.022). Conclusion: PV flow reversal is associated with a worse 5-year composite of mortality, mitral intervention, or AF in patients with significant dMR.

Concordance and Discordance of Echocardiographic Parameters Recommended for Assessing the Severity of Mitral Regurgitation

BACKGROUND

The American College of Cardiology/American Heart Association and American Society of Echocardiography guidelines recommend assessing several echocardiographic parameters when evaluating mitral regurgitation (MR) severity. These parameters can be discordant, making the assessment of MR challenging. The degree to which echocardiographic parameters of MR severity are concordant is not well studied.

METHODS

We enrolled 159 patients in a prospective multicenter study. Eight parameters were included in this analysis: proximal isovelocity surface area (PISA)-derived regurgitant volume, PISA-derived effective regurgitant orifice area, vena contracta, color Doppler jet/left atrial area, left atrial volume index, left ventricular end-diastolic volume index, peak E wave, and the presence of pulmonary vein systolic reversal. Each echocardiographic parameter was determined to represent severe or nonsevere MR according to the American Society of Echocardiography guidelines. A concordance score was calculated as [Formula: see text] so that a higher score reflects greater concordance. There was no discordance when all the echocardiographic parameters agreed and high discordance when 3 or 4 parameters were discordant.

RESULTS

The mean concordance score was 75±14% for the entire cohort. There were 9 (6%) patients with complete agreement of all parameters and 61 (38%) with high discordance. There was greater discordance in patients with severe MR but no difference between primary versus secondary or central versus eccentric jets. There was an improvement in concordance when only considering PISA-based regurgitant volume, PISA-based effective regurgitant orifice area, and vena contracta with agreement in 68% of patients.

CONCLUSIONS

There was limited concordance between the echocardiographic parameters of MR severity, and the discordance was worse with more severe MR. Concordance improved when considering only 3 quantitative measures of vena contracta and PISA-based effective regurgitant orifice area and regurgitant volume. These findings highlight the challenges facing echocardiographers when assessing the severity of MR and emphasize the difficulty of using an integrated approach that incorporates multiple components. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT04038879.

Stiff Left Atrial Syndrome; Prospects and Possibilities. Retrospective Analysis and Review of the Literature

OBJECTIVES

Stiff left atrial syndrome is an intriguing clinical phenomena characterized by reduced left atrial compliance, pulmonary venous hypertension and exacerbations of volume overload. We conducted a retrospective review of patients diagnosed with stiff left atrial syndrome at our center.

METHODS

All patients admitted to our hospital with volume overload and pulmonary venous hypertension who were diagnosed with stiff left atrial syndrome based on evidence by echocardiogram and right heart catheterization between July 2011 and July 2013 were included in this retrospective review.

RESULTS

Twentythree patients (mean age 73 ± 11 years, 39% male and 61% female) were diagnosed with stiff left atrial syndrome at our center. Thirty-five percent had persistent while 39% had permanent atrial fibrillation. Mean duration of atrial fibrillation was 7.6 ± 2.1 years. Forty-three percent of patients had long standing hypertension. There was no mitral regurgitation in 39% of patients while 48% had mild mitral regurgitation. On right heart catheterization, mean right atrial pressure was 12.6±4.8 mm of Hg, mean pulmonary arterial pressure was 33±7.2 mm of Hg, mean pulmonary capillary wedge pressure was 24.8± 4.2mm of Hg while peak V waves were seen at mean of 37.8± 5.3 mm of Hg. Mean left atrial volume index was 49.8±17.1 mL/m 2. After the initial diagnosis with a two year follow- up, there were no readmissions in 65% of patients who were on appropriate diuretic therapy and had regular clinical visits. Frequent readmissions were seen in 35% of patients inspite of appropriate diuretic therapy. All-cause mortality rate was 4.3% at two year follow up.

CONCLUSION

In patients with stiff left atrial syndrome, the presence of left atrial dilation, long standing atrial fibrillation and hypertension are the key factors associated with pathogenesis and clinical course. Close follow up and monitoring of volume status is essential to prevent hospital readmissions and improve long term prognosis.

A Comparative Assessment of Echocardiographic Parameters for Determining Primary Mitral Regurgitation Severity Using Magnetic Resonance Imaging as a Reference Standard

BACKGROUND

The American Society of Echocardiography (ASE) guidelines suggest the use of several echocardiographic methods to assess mitral regurgitation severity using an integrated approach, without guidance as to the weighting of each parameter. The purpose of this multicenter prospective study was to evaluate the recommended echocardiographic parameters against a reference modality and develop and validate a weighting for each echocardiographic measure of mitral regurgitation severity.

METHODS

This study included 112 patients who underwent evaluation with echocardiography and magnetic resonance imaging (MRI). Echocardiographic parameters recommended by the ASE were included and compared with MRI-derived regurgitant volume (MRI-RV).

RESULTS

Echocardiographic parameters that correlated best with MRI-RV were proximal isovelocity surface area (PISA) radius (r = 0.65, P < .0001), PISA-derived effective regurgitant orifice area (r = 0.65, P < .0001), left ventricular end-diastolic volume (r = 0.56, P < .0001), and PISA-derived regurgitant volume (r = 0.52, P < .0001). In the linear regression models PISA-derived effective regurgitant orifice area, PISA-derived regurgitant volume, left ventricular end-diastolic volume, and the presence of a flail leaflet independently predicted MRI-RV.

CONCLUSION

Echocardiographic parameters of mitral regurgitation as recommended by the ASE had moderate correlations with MRI-RV. The best predictors of MRI-RV were PISA-derived effective regurgitant orifice area, PISA-derived regurgitant volume, left ventricular end-diastolic volume, and the presence of a flail leaflet, suggesting that these parameters should be weighted more heavily than other echocardiographic parameters in the application of the ASE-recommended integrated approach.

Assessment of the severity of native mitral valve regurgitation

Mitral regurgitation (MR) is a major cause of cardiovascular morbidity and mortality. MR is classified as primary (organic) if it is due to an intrinsic valve abnormality, or secondary (functional) if the etiology is because of remodeling of left ventricular geometry and/or valve annulus. Transthoracic echocardiography (TTE) is the initial modality for MR evaluation. Parameters used for the assessment of MR include valve structure, cardiac remodeling, and color and spectral Doppler. Quantitative measurements include effective regurgitant orifice area, regurgitant volume, and regurgitant fraction. Knowledge of advantages and limitations of echo-Doppler parameters is essential for accurate results. An integrative approach is recommended in overall grading of MR as mild, moderate, or severe since singular parameters may be affected by several factors. When the mechanism and/or grade of MR is unclear from the TTE or is discrepant with the clinical scenario, further evaluation with transesophageal echocardiography or cardiac magnetic resonance imaging is recommended, the latter emerging as a powerful MR quantitation tool.

How to grade mitral regurgitation: an integrative approach

Evaluation of mitral regurgitation (MR) severity remains complex and challenging. An integrative approach to grading MR is recommended. The use of multiple Doppler methods should be used to help discriminate between grades of severity. Importantly, MR severity should always be considered in the context of clinical data. The emerging inclusion of 3-dimensional echocardiography may provide complementary data for MR quantification and better anatomic and pathophysiological detail of the mitral valve. This article summarizes recommendations for MR assessment and highlights the importance of an integrated approach, using anatomic information as well as qualitative and quantitative Doppler measures.

Echocardiographic Assessment of Left Ventricular Function in Type 1 Gaucher's Disease

There is predominate opinion among physicians managing type 1 Gauchers' disease (GD) that cardiac involvement is not an issue in these patients. In order to follow this hypothesis, we prospectively investigated 15 adult imiglucerase-treated type 1 GD patients by echocardiography, Doppler, and tissue Doppler echocardiography. This was a case-controlled study with 18 matched healthy volunteers. The obtained data was correlated with the levels of NT-proBNP (brain natriuretic peptide). None of the GD patients had clinical signs of heart disease. In 3 of the 15 patients, we observed echocardiographic signs of aortic and mitral valve calcification. The left ventricular systolic function was within normal limits. Compared to the control group, there was no statistically significant difference observed in the most sensitive indices of left ventricular diastolic function, parameter E_m (P = .095), and E/E_m ratio (P = .097), as demonstrated by tissue Doppler echocardiography. However, there was a positive correlation between the E/E_m ratio and NT-proBNP plasma levels (P = .009). In conclusion, the prospective echocardiographic study of type 1 GD patients did not validate any left ventricular dysfunction. But, the E/E_m ratio showed a strong statistical correlation with the most sensitive indicators of heart failure, NT-proBNP. Research on larger groups of patients and the usage of even more sensitive methods as strain-rate imaging will be necessary to confirm eventual myocardial involvement in GD patients.

The syndrome of cardiac failure in adults with congenitally corrected transposition

OBJECTIVES

To assess neurohormonal activation of cardiac failure in adults with congenitally corrected transposition, and to determine the most sensitive marker for recognition of the cardiac failure.

BACKGROUND

The onset of morphologically right ventricular dysfunction is unpredictable in patients with congenitally corrected transposition, the combination of discordant atrioventricular and ventriculo-arterial connections, and its markers are unknown.

METHODS

We measured amino terminal pro brain natriuretic peptide in 19 patients, aged 35 plus or minus 13.1 years, and in 19 control subjects. Morhologically right ventricular function was assessed by echocardiography, including tissue Doppler echocardiography and magnetic resonance imaging or multislice computed tomography.

RESULTS

The patients showed a highly significant increase in the levels of amino terminal pro brain natriuretic peptide, the levels being significantly elevated even in asymptomatic patients. Left atrial dimensions were larger in patients, and significantly lower tissue Doppler echocardiographic velocities were measured at the lateral site of the tricuspid annulus and at the basal segment of the interventricular septum. The ejection fraction of the morphologically right ventricle correlated significantly with the levels of brain natriuretic peptide, and with left atrial dimensions.

CONCLUSIONS

Neurohormonal activation is present in patients with congenitally corrected transposition even when they are asymptomatic. It is correlated with left atrial dimensions and tissue Doppler echocardiographic parameters. Levels of brain natriuretic peptide, and peak tricuspid early diastolic annular velocity, are the earliest and most sensitive markers of morphologically right ventricular dysfunction.

Assessment of functional anatomy of the mitral valve in patients with mitral regurgitation with cine magnetic resonance imaging: comparison with transesophageal echocardiography and surgical results

The ability of magnetic resonance imaging (MRI) to accurately define the functional anatomy of mitral regurgitation was assessed. Transesophageal echocardiography (TEE) and cine MRI were performed on 43 patients with mitral regurgitation and were compared for the jet number, location, direction and presence of a prolapse (atrial displacement, malapposition or a flail). In 36 patients, diagnostic accuracy in reference to surgery was assessed. Comparing TEE and MRI the jet number and location were judged in concordance in 86% of patients. Jet location did not show a significant difference (Wilcoxon: P = 0.66) and both modalities correlated strongly (Spearman: r = 0.68, P<0.0001). Jet direction was judged with high concordance (kappa=0.63). Additionally, prolapse evaluation showed high concordance (kappa: valve, 0.63; anterior mitral leaflet, 0.70; posterior mitral leaflet, 0.73). Compared with surgery, the sensitivity for the detection of malapposition of any leaflet or one of both leaflets ranged between 75% and 93% for TEE and 71% and 89% for MRI. Specificities ranged between 88 and 96% for TEE and 88 and 100% for MRI. TEE detected torn chordae in all ten patients, six of which were missed by MRI. MRI is comparable with TEE in prolapse and jet evaluation. MRI is inferior to TEE in depicting anatomical details such as torn chordae.

A practical approach to the quantification of valvular regurgitation

This article reviews the methods of determining the severity of mitral and aortic regurgitation, primarily the quantitation using Doppler echocardiography. The Doppler methods, including spatial mapping, proximal flow convergence, vena contracta, continuous-wave Doppler density, and upstream or downstream effects are explained. Various practical pitfalls and performance issues that impact the reliability of these techniques are discussed.

An initial application of transesophageal Doppler echocardiography in experimental small animal models

This study examined whether an intracardiac echocardiography catheter could be used for transesophageal echocardiography (TEE) examinations in normal rats, and intraoperative TEE in small animal models of disease. The study used 30 Sprague-Dawley normal rats, 10 rats undergoing coronary artery ligation, and 10 rats with experimentally induced mitral regurgitation. The rats were anesthetized with isoflurane and intubated. An intracardiac echocardiographic catheter was inserted into the esophagus. M-mode, 2-dimensional, and Doppler studies were performed in multiple views. TEE probe insertions were successful in all animals. Intraoperative TEE was safely performed in the rat models of myocardial infarction or mitral regurgitation. Mitral regurgitation was well assessed using color Doppler and pulmonary venous flow. This study demonstrates that TEE (including intraoperative TEE) can be safely performed in rats using an intracardiac echocardiographic catheter. It provides a new approach to the assessment of cardiac function and valvular regurgitation in small animals.

Mild to moderate mitral regurgitation in patients undergoing coronary bypass grafting: effects on operative mortality and long-term significance

BACKGROUND

Patients undergoing bypass grafting (CABG) often present with mitral regurgitation (MR). While surgical strategy for patients with either trace or severe MR is well established, the need for a valve procedure with mild (2) to moderate (3+) mitral regurgitation is controversial.

METHODS

We reviewed 1,939 consecutive CABG patients (1987 to 1999). A preoperative echocardiogram performed when clinically indicated graded MR from 1 to 4+. Patient characteristics, hospital mortality, and long-term survival were compared between 167 patients with grade 2 to 3+ MR and controls. A multivariate analysis identified independent predictors for long-term mortality.

RESULTS

The MR patients were more often female and older; had increased comorbidities including hypertension, diabetes, and heart failure; had more extensive coronary disease and worse left ventricular (LV) function; and required urgent surgery more often. Operative mortality was 0.8% in no MR patients and 1.8% in MR patients (p not significant). Long-term survival for MR patients with poor LV function (LV grade 3 to 4) was significantly lower (53% versus 75% at 10 years, p = 0.001). Independent predictors of poor long-term survival were advanced age, LV dysfunction, heart failure, diabetes, prior cerebrovascular accident, peripheral vascular disease, and no left internal mammary artery use.

CONCLUSIONS

Coronary artery bypass graft patients with mild or moderate MR have worse baseline characteristics but operative mortality with CABG alone is not significantly increased. Long-term prognosis for MR patients with poor LV function is worse compared with patients with no MR but MR was not an independent predictor of long-term mortality. To determine whether surgical correction of MR would improve results, a prospective randomized trial seems warranted.

Pulmonary venous flow by doppler echocardiography: revisited 12 years later

In 2003, pulmonary venous flow (PVF) evaluation by Doppler echocardiography is being used daily in clinical practice. Twelve years ago, we reviewed the potential uses of PVF in various conditions. Some of its important uses in cardiology have materialized, while others have not and have been supplanted by newer approaches. Current applications of measuring PVF have included: differentiating constrictive pericarditis from restriction, estimation of left ventricular (LV) filling pressures, evaluation of LV diastolic dysfunction and left atrial (LA) function, and grading the severity of mitral regurgitation (MR). However, there have been a number of controversies raised in the use of PVF profiles. Using transthoracic echocardiography, there may be technical issues in measuring the atrial reversal flow velocity. The use of PVF in the evaluation of the severity of MR is not always specific and can be affected by atrial fibrillation (AF) and elevated mean LA pressure. Mitral valvuloplasty and radiofrequency ablation for AF, which are the newer applications of PVF in monitoring invasive procedures, are mentioned. This article reviews the important clinical role of Doppler evaluation of PVF, discusses its limitations and pitfalls, and highlights its newer applications.

Pulmonary venous flow determinants of left atrial pressure under different loading conditions in a chronic animal model with mitral regurgitation

BACKGROUND

The aim of our study was to quantitatively compare the changes and correlations between pulmonary venous flow variables and mean left atrial pressure (mLAP) under different loading conditions in animals with chronic mitral regurgitation (MR) and without MR.

METHODS

A total of 85 hemodynamic conditions were studied in 22 sheep, 12 without MR as control (NO-MR group) and 10 with MR (MR group). We obtained pulmonary venous flow systolic velocity (Sv) and diastolic velocity (Dv), Sv and Dv time integrals, their ratios (Sv/Dv and Sv/Dv time integral), mLAP, left ventricular end-diastolic pressure, and MR stroke volume. We also measured left atrial a, x, v, and y pressures and calculated the difference between v and y pressures.

RESULTS

Average MR stroke volume was 10.6 +/- 4.3 mL/beat. There were good correlations between Sv (r = -0.64 and r = -0.59, P <.01), Sv/Dv (r = -0.62 and r = -0.74, P <.01), and mLAP in the MR and NO-MR groups, respectively. Correlations were also observed between Dv time integral (r = 0.61 and r = 0.57, P <.01) and left ventricular end-diastolic pressure in the MR and NO-MR groups. In velocity variables, Sv (r = -0.79, P <.001) was the best predictor of mLAP in both groups. The sensitivity and specificity of Sv = 0 in predicting mLAP 15 mm Hg or greater were 86% and 85%, respectively.

CONCLUSION

Pulmonary venous flow variables correlated well with mLAP under altered loading conditions in the MR and NO-MR groups. They may be applied clinically as substitutes for invasively acquired indexes of mLAP to assess left atrial and left ventricular functional status.

Elevated circulating levels of serum tumor necrosis factor-alpha in patients with hemodynamically significant pressure and volume overload

OBJECTIVES

We sought to determine whether serum tumor necrosis factor-alpha (TNF-alpha) levels are elevated in patients with hemodynamically significant pressure and volume overload.

BACKGROUND

It has been previously shown that TNF-alpha messenger ribonucleic acid (mRNA) and protein are rapidly expressed in the hearts of animal models subjected to abrupt hemodynamic overloading. The clinical significance of these experimental findings has not been tested in pathophysiologically relevant clinical models in human subjects.

METHODS

We prospectively measured serum TNF-alpha levels and serum TNF receptor 1 and 2 levels in 21 patients with severe aortic stenosis (AS), in 26 patients with 3+ to 4+ mitral regurgitation (MR) and in normal age- and gender-matched control subjects. Patients with AS and MR were either in New York Heart Association (NYHA) functional class I or II and had no significant coronary disease. We compared the cytokine levels among the groups using analysis of variance. We related cytokine levels to the severity of AS using simple regression analysis.

RESULTS

Serum TNF-alpha levels in patients with AS (2.1 +/- 1.6 pg/ml, n = 21) and MR (1.3 +/-0.7 pg/ml, n = 26) were significantly higher than those in the control subjects (0.7 +/-0.2 pg/ml, n = 28). Serum TNF receptor 1 and 2 levels were also higher in patients with AS and MR than in control subjects. Cytokine levels were higher in patients in NYHA class II than in those in class I. In patients with a normal ejection fraction (>50%, n = 16), there was a mild positive correlation (r = 0.56, p = 0.025) between serum TNF-alpha levels and the mean gradient across the aortic valve.

CONCLUSIONS

This study demonstrates that serum TNF-alpha is elevated in patients with chronic hemodynamic overloading and early cardiac decompensation. Furthermore, these findings suggest not only that peripheral TNF-alpha levels correlate with the severity of the hemodynamic pressure overload, but also that peripheral TNF-alpha and TNF receptor levels increase in direct relation to deteriorating NYHA functional class.