"Left ventricular filling pressure(s)" - Ambiguous and misleading terminology, best abandoned

A prospective analysis of the correlation between ultrasonic B-lines, cardiac tissue doppler signals and left ventricular end-diastolic pressure in patients with severe aortic stenosis

BACKGROUND

The development of heart failure is a turning point in the natural course of aortic stenosis (AS). Pulmonary oedema and elevated left ventricular pressure (LVP) are cardinal features of heart failure. Evaluating pulmonary oedema by lung ultrasound involves taking the upper hand with a bedside noninvasive tool that may reflect LVP.

AIM

We sought to assess the correlation between sonographic pulmonary congestion, invasive LV pre-A pressure, and echocardiographic LV end-diastolic pressure (LVEDP) in symptomatic AS patients receiving transcatheter aortic valve replacement.

METHODS

Forty-eight consecutive patients with severe AS and planned transcatheter aortic valve implantation (TAVI) were enrolled. LVEDP was estimated to be normal or elevated using the ASE/EACVI algorithm and transmitral Doppler indices, the E/A ratio, the E/e', and the left atrial volume index. Invasive LV pre-A pressure was used as a reference, with > 12 mm Hg defined as elevated.

RESULTS

Forty-eight patients (25 women (52%), mean age 75 years, standard deviation (SD) ± 7.7 years) were enrolled in the study. We detected severe B-lines (≥ 30) in 13 (27%) patients and moderate B-lines (15-30) in 33 (68.6%) patients. The number of B-lines increased significantly with the severity of New York Heart Association (NYHA) functional classes (Fig. 1). The B-line count was 14 ± 13 in NYHA class I patients, 20 ± 20 in class II patients, and 44 ± 35 in class III patients (p < 0.05, rho = 0.384). The number of B-lines was correlated with the E/E' ratio (R = 0.664, p < 0.0001) and the proBNP level (R = 0. 882, p < 0.008). We found no significant correlation with the LVEDP or LVEF. The LVEDP correlated well with the E/E' ratio (R = 0.491, p < 0.001) but not at all with E/A, DT, or LAVI. All patients had an elevated LVEDP > 12, with a mean pressure of 26 mmHg, a minimum of 13 mmHg, and a maximum of 45 mmHg, with an SD of 7.85.

CONCLUSION

Assessing lung ultrasonic B-lines is a straightforward and practical approach to identifying pulmonary oedema in AS patients. The number of B-lines correlated with the E/E' ratio and the functional status of patients but did not correlate with invasive LVEDP or LVEF. All patients had elevated LVEDP that correlated with E/E'.

Risk of supranormal left ventricular ejection fraction in patients with aortic stenosis

BACKGROUND

Cardiovascular events are increasing in patients with supranormal left ventricular ejection fraction (snLVEF). However, the effect of snLVEF in patients with aortic stenosis (AS) remains unclear, especially in patients with moderate AS.

HYPOTHESIS

This study aimed to evaluate the prognosis of mortality and heart failure (HF) in patients with LVEF ≥ 50% and moderate or severe AS.

METHODS

This retrospective study targeted patients with moderate or severe AS and LVEF > 50%. LVEF of 50%-65% was classified as normal LVEF (nLVEF, nEF group) and >65% as snLVEF (snEF group). AS severity was stratified based on the aortic valve area into moderate (1.0-1.5 cm²) and severe (<1.0 cm²). Primary outcomes included all-cause mortality and HF hospitalization.

RESULTS

A total of 226 participants were included in this study. There were 67 and 65 participants with moderate AS in snEF (m-snEF) and nEF groups (m-nEF), respectively, and 41 and 53 participants with severe AS in the snEF (s-snEF) and nEF groups (s-nEF), respectively. During the observation period (median: 554 days), the primary composite outcome occurred in 108 individuals. Cox hazard analysis revealed no significant differences among the four groups in primary composite outcomes. With respect to HF hospitalization, the adjusted hazard ratios (95% confidence intervals) with m-snEF as the reference were as follows: m-nEF, 0.41 (0.19-0.89); s-nEF, 1.43 (0.76-2.67); and s-snEF, 1.83 (1.00-3.35).

CONCLUSIONS

The risk of HF hospitalization for m-snLVEF was higher than m-nLVEF and not significantly different from s-nLVEF.

Left atrial strain as a predictor of left ventricular filling pressures in coronary artery disease with preserved ejection fraction: a comprehensive study with left ventricular end-diastolic and pre-atrial contraction pressures

Assessing left ventricular (LV) filling pressure (LVFP) is challenging in patients with coronary artery disease (CAD) and preserved LV ejection fraction (LVEF). We aimed to correlate left atrial strain (LAS) with two invasive complementary parameters of LVFP and compared its accuracy to other echocardiographic data to predict high LVFP. This cross-sectional, single-center study enrolled 81 outpatients with LVEF > 50% and significant CAD from a database. Near-simultaneous echocardiography and invasive measurements of both LV end-diastolic pressure (LVEDP) and LV pre-atrial contraction (pre-A) pressure were performed in each patient, based on the definition of LVEDP > 16 mmHg and LV pre-A > 12 mmHg as high LVFP. A moderate to strong correlation was observed between LAS reservoir (LASr), contractile strain, and LVEDP (r: 0.67 and 0.62, respectively; p < 0.001); the same was true for LV pre-A (r: 0.65 and 0.63, respectively; p < 0.001). LASr displayed good diagnostic performance to identify elevated LVFP, which was higher when compared to traditional parameters. Median value of LASr was higher for an isolated increase of LVEDP than for simultaneously high LV pre-A. The cutoff found to predict high LVFP was lower for LV pre-A than that one for LVEDP. In the current study, LASr did not provide an additional contribution to the 2016 diastolic function algorithm. LAS is a valuable tool for predicting LVFP in patients with CAD and preserved LVEF. The choice of LVEDP or LV pre-A as the representative marker of LVFP leads to different cutoffs to predict high pressures. The best strategy for adding this tool to a multiparametric algorithm requires further investigation.

Pathophysiology of Heart Failure with Preserved Ejection Fraction

Heart failure with preserved ejection fraction (HFpEF) is a major public health problem that affects half of all patients with HF. It is rising in prevalence, is associated with high morbidity and mortality, and has very few effective treatments. HFpEF is currently understood as a heterogeneous syndrome originating from the interplay of cardiac and extracardiac abnormalities. The most important pathophysiology in patients with HFpEF is diastolic dysfunction, which presents with impairments in relaxation or increases in chamber stiffness that lead to an increase in left ventricular filling pressures at rest or during exercise that causes dyspnea.

The utility of cardiovascular imaging in heart failure with preserved ejection fraction: diagnosis, biological classification and risk stratification

Heart failure with preserved ejection fraction (HFpEF) does not exist as a singular clinical or pathological entity but as a syndrome encompassing a wide range of clinical and biological phenotypes. There is an urgent need to progress from the unsuccessful 'one-size-fits-all' approach to more precise disease classification, in order to develop targeted therapies, personalise risk stratification and guide future research. In this regard, this review discusses the current and emerging roles of cardiovascular imaging for the diagnosis of HFpEF, for distilling HFpEF into distinct disease entities according to underlying pathobiology and for risk stratification.

Understanding preload and preload reserve within the conceptual framework of a limited range of possible left ventricular end-diastolic volumes

Preload has been variously defined, but if there is to be a direct relationship with activity of the Frank-Starling mechanism in its action to increase the force and extent of contraction, preload must directly reflect myocardial stretch. The Frank-Starling mechanism is activated during any stretch of a cardiac chamber beyond its resting size, which is present immediately before contraction. Every left ventricle has an intrinsic and limited range of possible volumes at end diastole. There is a curvilinear relationship between left ventricular (LV) end-diastolic pressure (LVEDP) and LV end-diastolic volume (LVEDV), and, at maximal or near maximal LVEDV, there will be a high LVEDP. Within the possible range, the LVEDV will be determined by the extent of filling, any change in LVEDV will result in changed activity of the Frank-Starling mechanism, and change in LVEDV might, therefore, be considered to represent change in preload. On the other hand, it is the difference between the current and the maximal possible LVEDV (or the preload reserve) that may be of the most clinical relevance. There is a reciprocal relationship between preload and preload reserve, with minor or absent LV preload reserve indicating that there will be either minimal or no increase in stroke volume following intravenous fluid administration. As left atrial pressure can remain within the normal range when the LVEDP is elevated, it is LVEDP, and not left atrial pressure, that provides the most reliable guide to preload reserve in an individual at a specific period in time.

Correlation of left atrial strain with left ventricular end-diastolic pressure in patients with normal left ventricular ejection fraction

Left ventricular diastolic dysfunction (LVDD) remains challenging to be assessed by echocardiography. We sought to explore the relationship between left atrial strain and left ventricular (LV) diastolic function in patients with normal left ventricular ejection fraction (LVEF) by invasive left-heart catheterization. 55 consecutive individuals with LVEF > 50% underwent LV catheterization. Standard transthoracic echocardiography was performed during 12 h before or after the procedure. Left atrial (LA) strain were obtained by speckle tracking echocardiography. When LVEF ≥ 50%, the group with elevated left ventricular end-diastolic pressure (LVEDP) (n = 35) showed decreased left atrial reservoir strain (LASr) (35.2 ± 7.7% vs 21.3 ± 7.2%, p < 0.001), left atrial conduit strain (LASct) (17.6 ± 6.3% vs 11.9 ± 4.1%, p < 0.001), left atrial contraction strain (LAScd) (16.6 ± 7.2% vs 9.5 ± 5.0%, p < 0.001) and increased E/e′ ration(8.9 ± 2.6 vs 10.1 ± 3.5, p = 0.17). LVEDP negatively correlated with LASr (R = 0.662, p < 0.001), LASct (R = 0.575, p < 0.001) and LAScd (R = 0.456, p < 0.001), but not with E/e′. LASr, LASct and LAScd were all independent predictors of elevated LVEDP (p < 0.05), with a higher C-statistic for the model including LASr (0.95, 0.86 and 0.93 respectively). The area under the curve (AUC) for LASr is 0.914 (cutoff value is 26.7%, sensitivity is 90%, specificity is 82.9%). In patients with normal LV ejection fraction, left atrial strain presented good correlation with LVEDP, and LASr was superior to LASct and LAScd to predict LVEDP. LA strain demonstrated better agreement with the invasive reference than E/e′.

Reliability of updated left ventricular diastolic function recommendations in predicting elevated left ventricular filling pressure and prognosis

An updated 2016 echocardiographic algorithm for diagnosing left ventricular (LV) diastolic dysfunction (DD) was recently proposed. We aimed to assess the reliability of the 2016 echocardiographic LVDD grading algorithm in predicting elevated LV filling pressure and clinical outcomes compared to the 2009 version.

METHODS

We retrospectively identified 460 consecutive patients without atrial fibrillation or significant mitral valve disease who underwent transthoracic echocardiography within 24 hours of elective heart catheterization. LV end-diastolic pressure (LVEDP) and the time constant of isovolumic pressure decay (Tau) were determined. The association between DD grading by 2009 LVDD Recommendations and 2016 Recommendations with hemodynamic parameters and all-cause mortality were compared.

RESULTS

The 2009 LVDD Recommendations classified 55 patients (12%) as having normal, 132 (29%) as grade 1, 156 (34%) as grade 2, and 117 (25%) as grade 3 DD. Based on 2016 Recommendations, 177 patients (38%) were normal, 50 (11%) were indeterminate, 124 (27%) patients were grade 1, 75 (16%) were grade 2, 26 (6%) were grade 3 DD, and 8 (2%) were cannot determine. The 2016 Recommendations had superior discriminatory accuracy in predicting LVEDP (P<.001) but were not superior in predicting Tau. During median follow-up of 416 days (interquartile range: 5 to 2004 days), 54 patients (12%) died. Significant DD by 2016 Recommendations was associated with higher risk of mortality (P=.039, subdistribution HR1.85 [95% CI, 1.03-3.33]) in multivariable competing risk regression.

CONCLUSIONS

The grading algorithm proposed by the 2016 LV diastolic dysfunction Recommendations detects elevated LVEDP and poor prognosis better than the 2009 Recommendations.