Reduced stroke distance of the left ventricular outflow tract is independently associated with long-term mortality, in patients hospitalized due to heart failure

New perspectives in the echocardiographic hemodynamics multiparametric assessment of patients with heart failure

International Guidelines consider left ventricular ejection fraction (LVEF) as an important parameter to categorize patients with heart failure (HF) and to define recommended treatments in clinical practice. However, LVEF has some technical and clinical limitations, being derived from geometric assumptions and is unable to evaluate intrinsic myocardial function and LV filling pressure (LVFP). Moreover, it has been shown to fail to predict clinical outcome in patients with end-stage HF. The analysis of LV antegrade flow derived from pulsed-wave Doppler (stroke volume index, stroke distance, cardiac output, and cardiac index) and non-invasive evaluation of LVFP have demonstrated some advantages and prognostic implications in HF patients. Speckle tracking echocardiography (STE) is able to unmask intrinsic myocardial systolic dysfunction in HF patients, particularly in those with LV preserved EF, hence allowing analysis of LV, right ventricular and left atrial (LA) intrinsic myocardial function (global peak atrial LS, (PALS)). Global PALS has been proven a reliable index of LVFP which could fill the gaps "gray zone" in the previous Guidelines algorithm for the assessment of LV diastolic dysfunction and LVFP, being added to the latest European Association of Cardiovascular Imaging Consensus document for the use of multimodality imaging in evaluating HFpEF. The aim of this review is to highlight the importance of the hemodynamics multiparametric approach of assessing myocardial function (from LVFP to stroke volume) in patients with HF, thus overcoming the limitations of LVEF.

Echocardiography-Derived Forward Left Ventricular Output Improves Risk Prediction in Systolic Heart Failure

BACKGROUND

Although it is widely used to classify patients with heart failure (HF), the prognostic role of left ventricular ejection fraction (LVEF) is debated. The aim of this study was to test the hypothesis that echocardiographic measures of forward left ventricular (LV) output, being more representative of cardiac hemodynamics, might improve risk prediction in a large cohort of patients with HF with systolic dysfunction.

METHODS

Consecutive stable patients with HF with LVEF <50% on guideline-recommended therapies undergoing echocardiography including the evaluation of forward LV output (i.e., LV outflow tract [LVOT] velocity-time integral [VTI], stroke volume index [SVi], and cardiac index) over a 6-year period were selected and followed for the end point of cardiac and all-cause death.

RESULTS

Among the 1,509 patients analyzed (mean age, 71 ± 12 years; 75% men; mean LVEF, 35 ± 9%), 328 (22%) died during a median follow-up period of 28 months (interquartile range, 14-40 months), 165 (11%) of cardiac causes. On multivariable regression analysis, LVOT VTI (P < .001), SVi (P < .001), and cardiac index (P < .001), but not LVEF (P > .05), predicted cardiac and all-cause death. The optimal prognostic cutoffs for LVOT VTI, SVi, and cardiac index were 15 cm, 38 mL/m2, and 2 L/min/m2, respectively. Adding each of these measures to a multivariable risk model (including clinical, biohumoral, and echocardiographic markers) improved risk prediction (P < .001). Among the different measures of forward LV output, cardiac index was less accurate than LVOT VTI and SVi.

CONCLUSIONS

The echocardiographic evaluation of forward LV output improves risk prediction in patients with HF across a wide LVEF spectrum over other well-established clinical, biohumoral, and echocardiographic prognostic markers.

Left ventricular outflow tract velocity-time integral improves outcome prediction in patients with secondary mitral regurgitation

AIMS

Left ventricular outflow velocity-time integral (LVOT-VTI) has been shown to improve outcome prediction in different patients' subsets, with or without heart failure (HF). Nevertheless, the prognostic value of LVOT-VTI in patients with HF and secondary mitral regurgitation (MR) has never been investigated so far. Therefore, in the present study, we aimed to assess the prognostic value different metrics of LV forward output, including LVOT-VTI, in HF patients with secondary MR.

METHODS AND RESULTS

Consecutive patients with HF and moderate-to-severe/severe secondary MR and systolic dysfunction (i.e., left ventricular ejection fraction [LVEF] <50%) were retrospectively selected and followed-up for the primary endpoint of cardiac death. Out of the 287 patients analyzed (aged 74 ± 11 years, 70% men, 46% ischemic etiology, mean LVEF 30 ± 9%, mean LVOT-VTI 20 ± 5 cm), 71 met the primary endpoint over a 33-month median follow-up (16-47 months). Patients with an LVOT-VTI ≤17 cm (n = 96, 32%) showed the greatest risk of cardiac death (Log Rank 44.3, p < 0.001) and all-cause mortality (Log rank 8.6, p = 0.003). At multivariable regression analysis, all the measures of LV forward volume (namely LVOT-VTI, stroke volume index, cardiac output, and cardiac index) were predictors of poor outcomes. Among these, LVOT-VTI was the most accurate in risk prediction (univariable C-statistics 0.70 [95%CI 0.64-0.77]).

CONCLUSION

Left ventricular forward output, noninvasively estimated through LVOT-VTI, improves outcome prediction in HF patients with low LVEF and secondary MR.

From left ventricular ejection fraction to cardiac hemodynamics: role of echocardiography in evaluating patients with heart failure

In clinical practice heart failure (HF) patients are generally classified on the basis of left ventricular (LV) ejection fraction. This approach, however, has important limitations. According to the definition of HF as a clinical syndrome that results from any impairment of LV filling or ejection of blood, a more articulated hemodynamic categorization of HF patients taking into account both LV forward flow and filling pressure would be desirable. However, the reliability of hemodynamic measures using echocardiographic techniques, which are the most used in current clinical practice for evaluation of HF patients, needs to be clarified. The aim of this article, therefore, is to verify whether echocardiography has acceptable feasibility, accuracy and reproducibility for the noninvasive evaluation of LV hemodynamics. This evaluation is necessary to progress to a hemodynamic characterization of HF patients that would ultimately overcome the HF classification based on ejection fraction.

Left ventricular output indices in hospitalized heart failure: when "simpler" may not mean "better"

Assessment of left ventricular (LV) output in hospitalized patients with heart failure (HF) is important to determine prognosis. Although echocardiographic LV ejection fraction (EF) is generally used to this purpose, its prognostic value is limited. In this investigation LV-EF was compared with other echocardiographic per-beat measures of LV output, including non-indexed stroke volume (SV), SV index (SVI), stroke distance (SD), ejection time (ET), and flow rate (FR), to determine the best predictor of all-cause mortality in patients hospitalized with HF. A final cohort of 350 consecutive patients hospitalized with HF who underwent echocardiography during hospitalization was studied. At a median follow-up of 2.7 years, 163 patients died. Non-survivors at follow-up had lower SD, SVI and SV, but not ET, FR and LV-EF than survivors. At multivariate analysis, only age, systolic blood pressure, chronic kidney disease, chronic obstructive pulmonary disease, use of angiotensin-converting enzyme inhibitors/angiotensin receptor blockers and SVI remained significantly associated with outcome [HR for SVI 1.13 (1.04-1.22), P = 0.003]. In particular, for each 5 ml/m² decrease in SVI, a 13% increase in risk of mortality for any cause was observed. SVI is a powerful prognosticator in HF patients, better than other per-beat measures, which may be simpler but partial or incomplete descriptors of LV output. SVI, therefore, should be considered for the routine echocardiographic evaluation of patients hospitalized with HF to predict prognosis.

Left ventricular outflow tract velocity time integral in hospitalized heart failure with preserved ejection fraction

Aims

The prognostic implication of left ventricular outflow tract velocity time integral (LVOT‐VTI) on admission in hospitalized heart failure with preserved ejection fraction (HFpEF) patients has not been determined. We sought to investigate whether LVOT‐VTI on admission is associated with worse clinical outcomes in hospitalized patients with HFpEF.

Methods and results

We studied consecutive 214 hospitalized HFpEF patients who had accessible LVOT‐VTI data on admission, from a prospective HFpEF‐specific multicentre registry. The primary outcome of interest was the composite of all‐cause death and readmission due to heart failure. During a median follow‐up period of 688 (interquartile range 162–810) days, the primary outcome occurred in 83 patients (39%). The optimal cut‐off value of LVOT‐VTI for the primary outcome estimated by receiver operating characteristic analysis was 15.8 cm. Lower LVOT‐VTI was significantly associated with the primary outcome compared with higher LVOT‐VTI (P = 0.005). Multivariable Cox regression analyses revealed that lower LVOT‐VTI was an independent determinant of the primary outcome (hazard ratio 0.94, 95% confidence interval 0.91–0.98). In multivariable linear regression, haemoglobin level was the strongest independent determinant of LVOT‐VTI among clinical parameters (β coefficient = −0.61, P = 0.007). Furthermore, patients with lower LVOT‐VTI and anaemia had the worst clinical outcomes among the groups (P < 0.001).

Conclusions

Lower admission LVOT‐VTI was an independent determinant of worse clinical outcomes in hospitalized HFpEF patients, indicating that LVOT‐VTI on admission might be useful for categorizing a low‐flow HFpEF phenotype and risk stratification in hospitalized HFpEF patients.