A Novel Approach to Left Ventricular Filling Pressure Assessment: The Role of Hemodynamic Forces Analysis

Reliability of left ventricular hemodynamic forces derived from feature-tracking cardiac magnetic resonance

BACKGROUND

Hemodynamic forces (HDF) analysis has been proposed as a method to quantify intraventricular pressure gradients, however data on its reliability are still scanty. Thus, the aim of this study is to assess the reliability of HDF parameters derived from cardiac magnetic resonance (CMR).

METHODS

CMR studies of 25 athletes were analysed by two independent observers and then re-analysed by the same observer one week apart. Intraclass Correlation Coefficient (ICC [95% CI]) and Bland-Altman plots were used to assess association, agreement, and bias of the longitudinal (A-B) HDF, transverse (L-S) HDF, and Impulse Angle. The sample size required to detect a relative change in the HDF parameters was also calculated.

RESULTS

In terms of inter-observer variability, there was a good correlation for the A-B and L-S (ICC 0.85 [0.67-0.93] and 0.86 [0.69-0.94]; p<0.001 for both, respectively) and a moderate correlation for the Impulse Angle (ICC 0.73 [0.39-0.87]; p = 0.001). For intra-observer variability, A-B and L-S showed excellent correlation (ICC 0.91 [0.78-0.93] and 0.93 [0.83-0.97]; p<0.001 for both, respectively). Impulse Angle presented good correlation (ICC 0.80 [0.56-0.90]; p<0.001). Frame selection and aortic valve area measurements were the most vulnerable step in terms of reliability of the method. Sample size calculation to detect relative changes ranged from n = 1 to detect a 15% relative change in Impulse Angle to n = 171 for the detection of 10% relative change in A-B HDF.

CONCLUSIONS

The results of this study showed a low inter- and intra-observer variability of HDF parameters derived from feature-tracking CMR. This provides the fundamental basis for their use both in research and clinical practice, which could eventually lead to the detection of significant changes at follow-up studies.

Echocardiography-Derived Hemodynamic Forces Are Associated with Clinical Outcomes in Patients with Non-Ischemic Dilated Cardiomyopathy

Introduction: Non-ischemic dilated cardiomyopathy (NIDCM) is characterized by a reduced left ventricular (LV) ejection fraction (LVEF, <50%) and a high risk for heart failure (HF) and death. Echocardiography-derived hemodynamic forces (HDFs) may provide important information on LV mechanics, but their prognostic value is unknown. Aim: To explore the features of echocardiography-derived HDFs in NIDCM and their association with clinical endpoints. Methods: Asymptomatic, non-hospitalized NIDCM patients free from coronary artery disease and moderate or severe valvular heart disease were included in this single-center observational retrospective longitudinal study. Those with atrial fibrillation and a follow-up <12 months were excluded. Major adverse cardiovascular events (MACE) were defined as a composite of all-cause death, HF hospitalization, and ambulatory intravenous diuretics administration. LV HDFs were analyzed with a prototype software. Apex-base (HDFs-ab), lateral-septal (HDFs-ls), and HDFs-angle were computed. Results: Ninety-seven patients were included, sixty-seven (69%) were males, mean age was 62 ± 14 years, and mean LVEF was 39.2 ± 8.6%. During a median follow-up of 4.2 (3.1-5.1) years, 19 (20%) patients experienced MACE. These patients had a higher HDFs-angle (71.0 (67.0-75.0) vs. 68.0 (63.0-71.0)°, p = 0.005), lower HDFs-ls (1.36 (1.01-1.85) vs. 1.66 ([1.28-2.04])%, p = 0.015), but similar HDFs-ab (5.02 (4.39-6.34) vs. 5.66 (4.53-6.78)%, p = 0.375) compared to those without MACE. in a Cox regression analysis, HDFs-angle (HR 1.16 (95%-CI 1.04-1.30), p = 0.007) was associated with MACE, while other conventional echocardiography parameters, including LVEF and LV longitudinal strain, were not. Conclusions: HDFs-angle is associated with clinical endpoints in NIDCM. A higher HDFs-angle may be a marker of impaired myocardial performance in patients with reduced LVEF.

Unravelling the intricacies of left ventricular haemodynamic forces: age and gender-specific normative values assessed by cardiac MRI in healthy adults

AIMS

Haemodynamic forces (HDFs) provided a feasible method to early detect cardiac mechanical abnormalities by estimating the intraventricular pressure gradients. The novel advances in assessment of HDFs using routine cardiac magnetic resonance (CMR) cines shed new light on detection of preclinical dysfunction. However, definition of normal values for this new technique is the prerequisite for application in the clinic.

METHODS AND RESULTS

A total of 218 healthy volunteers [38.1 years ± 11.1; 111 male (50.9%)] were recruited and underwent CMR examinations with a 3.0T scanner. Balanced steady state free precession breath hold cine images were acquired, and HDF assessments were performed based on strain analysis. The normal values of longitudinal and transversal HDF strength [root mean square (RMS)] and ratio of transversal to longitudinal HDF were all evaluated in overall population as well as in both genders and in age-specific groups. The longitudinal RMS values (%) of HDFs were significantly higher in women (P < 0.05). Moreover, the HDF amplitudes significantly decreased with ageing in entire heartbeat, systole, diastole, systolic/diastolic transition, and diastolic deceleration, while increased in atrial thrust. In multivariable linear regression analysis, age, heart rate, and global longitudinal strain emerged as independent predictors of the amplitudes of longitudinal HDFs in entire heartbeat and systole, while left ventricular end-diastole volume index was also independently associated with longitudinal HDFs in diastole and diastolic deceleration (P < 0.05 for all).

CONCLUSION

Our study provided comprehensive normal values of HDF assessments using CMR as well as presented with specific age and sex stratification. HDF analyses can be performed with excellent intra- and inter-observer reproducibility.

Haemodynamic forces predicting remodelling and outcome in patients with heart failure treated with sacubitril/valsartan

AIMS

A novel tool for the evaluation of left ventricular (LV) systo-diastolic function through echo-derived haemodynamic forces (HDFs) has been recently proposed. The present study aimed to assess the predictive value of HDFs on (i) 6 month treatment response to sacubitril/valsartan in heart failure with reduced ejection fraction (HFrEF) patients and (ii) cardiovascular events.

METHODS AND RESULTS

Eighty-nine consecutive HFrEF patients [70% males, 65 ± 9 years, LV ejection fraction (LVEF) 27 ± 7%] initiating sacubitril/valsartan underwent clinical, laboratory, ultrasound and cardiopulmonary exercise testing evaluations. Patients experiencing no adverse events and showing ≥50% reduction in plasma N-terminal pro-B-type natriuretic peptide and/or ≥10% LVEF increase over 6 months were considered responders. Patients were followed up for the composite endpoint of HF-related hospitalisation, atrial fibrillation and cardiovascular death. Forty-five (51%) patients were responders. Among baseline variables, only HDF-derived whole cardiac cycle LV strength (wLVS) was higher in responders (4.4 ± 1.3 vs. 3.6 ± 1.2; p = 0.01). wLVS was also the only independent predictor of sacubitril/valsartan response at multivariable logistic regression analysis [odds ratio 1.36; 95% confidence interval (CI) 1.10-1.67], with good accuracy at receiver operating characteristic (ROC) analysis [optimal cutpoint: ≥3.7%; area under the curve (AUC) = 0.736]. During a 33 month (23-41) median follow-up, a wLVS increase after 6 months (ΔwLVS) showed a high discrimination ability at time-dependent ROC analysis (optimal cut-off: ≥0.5%; AUC = 0.811), stratified prognosis (log-rank p < 0.0001) and remained an independent predictor for the composite endpoint (hazard ratio 0.76; 95% CI 0.61-0.95; p < 0.01), after adjusting for clinical and instrumental variables.

CONCLUSIONS

HDF analysis predicts sacubitril/valsartan response and might optimise decision-making in HFrEF patients.

Acute Modification of Hemodynamic Forces in Patients with Severe Aortic Stenosis after Transcatheter Aortic Valve Implantation

Transcatheter aortic valve implantation (TAVI) is the established first-line treatment for patient with severe aortic stenosis not suitable for surgery. Echocardiographic evaluation of hemodynamic forces (HDFs) is a growing field, holding the potential to early predict improvement in LV function. A prospective observational study was conducted. Transthoracic echocardiography was performed before and after TAVI. HDFs were analyzed along with traditional left ventricular (LV) function parameters. Twenty-five consecutive patients undergoing TAVI were enrolled: mean age 83 ± 5 years, 74.5% male, mean LV Ejection Fraction (LVEF) at baseline 57 ± 8%. Post-TAVI echocardiographic evaluation was performed 2.4 ± 1.06 days after the procedure. HDF amplitude parameters improved significantly after the procedure: LV Longitudinal Forces (LF) apex-base [mean difference (MD) 1.79%; 95% CI 1.07-2.5; p-value < 0.001]; LV systolic LF apex-base (MD 2.6%; 95% CI 1.57-3.7; p-value < 0.001); LV impulse (LVim) apex-base (MD 2.9%; 95% CI 1.48-4.3; p-value < 0.001). Similarly, HDFs orientation parameters improved: LVLF angle (MD 1.5°; 95% CI 0.07-2.9; p-value = 0.041); LVim angle (MD 2.16°; 95% CI 0.76-3.56; p-value = 0.004). Conversely, global longitudinal strain and LVEF did not show any significant difference before and after the procedure. Echocardiographic analysis of HDFs could help differentiate patients with LV function recovery after TAVI from patients with persistent hemodynamic dysfunction.