P2603Impaired right ventricular force-frequency relationship in patients with heart failure is associated with diastolic dysfunction and worse functional capacity

Background

The force-frequency relationship (FFR) is an important intrinsic regulatory mechanism of cardiac contractility, related to changes in Ca2+ availability within the myocardial cell. In normal hearts this relationship is positive, so that an increase in contractile force is induced by elevation of the stimulation frequency. In heart failure (HF), the force-frequency relationship can be markedly depressed, but most studies focused their attention on left ventricular function and little is known about the right ventricle (RV).

Purpose

We aimed at performing a comprehensive analysis of HF phenotypes based on the right ventricular force-frequency relationship. To this purpose we stratified a large cohort of HF patients using the relationship between RV function (assessed by tricuspid annular plane systolic excursion, TAPSE) and heart rate (HR) during a symptom-limited cardiopulmonary exercise test (CPET).

Material and methods

We prospectively enrolled 184 HF patients, irrespective of their LV ejection fraction. We performed a stress echocardiographic evaluation using a tiltable cycle ergometer, recording standard images to assess LV systolic, diastolic, and valvular function.

We divided patients in 2 groups using the slope of the linear relationship between TAPSE and HR at rest and at peak exercise, as follows: slope ≥0,01 for “positive” FFR, slope <0,01 for “flat or negative” FFR.

Differences between groups were tested using unpaired t-tests for continuous variables (or Mann-Whitney U tests, when appropriate) and chi-square tests for categorical variables.

Results

55 patients had a “flat or negative” FFR: they were slighty older (age 70±10 vs. 66±12; p=0,036), but the 2 groups had similar clinical characteristics such as hypertension, diabetes or COPD rate.

Patients with a “flat or negative” FFR had a worse diastolic function, with higher left ventricular filling pressures (E/e' ratio 24±10 vs. 19±11 p=0,022) and left atrial volume (LAVi 55±29 ml/m2 vs. 44±20 ml/m2; p=0,009). No differences in LV ejection fraction, mitral regurgitation and pulmonary artery systolic pressure were observed between the groups.

TAPSE at rest was similar between the groups (18±5 mm vs. 18±4 mm; p=0,553) but significantly different at peak exercise (16±4 mm vs. 22±5 mm; p<0,001). Average peak heart rate was similar in the 2 groups.

Patients with a “flat or negative” FFR exhibited a significantly lower peak VO2 (11,6±3,0 ml/min/kg vs. 13,5±4,4 ml/min/kg; p=0,003), whereas they had a higher VE/VCO2 slope (35,1±9,6 vs. 32,3±8,2 p=0,05).

RV Force-Frequency relationship

Conclusion

The “flat or negative” right ventricular force-frequency relationship identifies a peculiar phenotype, with a higher grade of diastolic dysfunction and an impaired exercise capacity. The inability to adapt right ventricular contractility with increasing heart rate seems not related to RV afterload (similar PASP increase) but rather to an intrinsic failure of the right heart.

P3549Impact of mitral regurgitation on alveolo-capillar membrane diffusion: an hemodynamic and functional study

Background

In HFrEF patients, high pulmonary vascular resistances (PVR) reflect a combined increase of pre- and post-capillary pressures, associated with worse outcome. Mitral regurgitation (MR) may play a role in this complex physiopathology. We sought to investigate MR impact on lung DLCO and pulmonary vascular hemodynamic in HFrEF patient.

Methods

22 HFrEF patients (age 67±11; LV EF) underwent right heart catheterization, rest and exercise echocardiography, right ventricle 3D assessment and lung alveolo-capillary membrane DLCO. We identified 2 subgroups according to normal (<3 WU, n=17) or abnormal (>3 WU, n=5) PVR.

Results

Abnormal PVR patients showed increased pulmonary artery pressures and TPG, reduced CO and pulmonary artery compliance. Total DLCO was not significantly different between groups. The membrane component (Dm) and the alveolar volume (Va) were significantly reduced in abnormal PVR group, while the capillary volume (VC) showed a strong trend toward higher values. Abnormal PVR group had a very high percentage of moderate-to-severe MR. The TASPE/SPAP ratio and the circumferential component of RV systolic function were significantly reduced in abnormal PVR group.

Normal PVR (n=17) Abnormal PVR (n=5) p NTproBNP, ng/L 3021±2527 7023±8785 0.55 MR moderate-to-severe, n (%) 3 (19%) 4 (80%) 0.025 TAPSE/SPAP, mm/mmHg 0.4761±0.1695 0.2956±0.0739 0.019 3D RV global EF, % 40.616±9.350 29.486±14.062 0.119 3D RV longitudinal EF, % 15.611±7.773 12.086±9.694 0.497 3D RV circumferential EF, % 31.0567±6.5744 21.1746±11.5823 0.019 Lung diffusion of CO (DLCO), ml/min/mmHg 19.021±4.643 15.233±1.761 0.197 Dm ml/min/mmHg 26.8±8.2 17.8±4.1 0.047 VC, ml 110±77 247±152 0.121

Graphics

Conclusion

The presence of severe MR, in this cohort of HFrEF patients, is associated with alveolar-capillary membrane remodeling (lower Dm), worse hemodynamic profile (higher PA pressures, lower PA compliance and higher PA resistance) and worse right ventricle to pulmonary circulation coupling (lower TAPSE/SPAP and lower 3D RV circumferential EF), confirming the use of therapeutic strategies aimed at correction of valvular disease.

P4504Pulmonary circulatory-right ventricular uncoupling in acute decompensated heart failure: a key mediator of congestion

Background

The degree of congestion in patients hospitalized for acute decompensated heart failure (ADHF) is estimated using traditional non-invasive markers such as echo-derived inferior vena cava diameter (IVCD) and NT-proBNP levels. The deterioration of right ventricular (RV) function and its uncoupling to pulmonary circulation (Pc) represents a turning point in terms of prognosis and clinical outcome in patients affected by heart failure. However, how RV-to-Pc uncoupling correlates with markers of decompensation and congestion in ADHF patients has never been explored.

Purpose

To investigate, in a cohort of ADHF patients, the association between the degree of RV-to-Pc uncoupling, assessed by the ratio between tricuspid annular plane systolic excursion (TAPSE) to pulmonary artery systolic pressure (PASP), IVCD and right atrial pressure (RAP) estimated at echocardiography.

Methods

Fourty-six ADHF patients both with reduced and preserved EF (mean age 73.15±10.85 years, 60.8% males) admitted to the Cardiology Department were prospectively enrolled within 24–48 hours from admission. In the acute phase all patients underwent transthoracic echocardiography and laboratory blood tests. Patients were then stratified in tertiles according to TAPSE/PASP ratio (group I: <0.4 mm/mmHg; group II: 0.4 to 0.6 mm/mmHg and group III: >0.6 mm/mmHg) correlating the degree of RV-to-Pc with non-invasive markers of congestion such as NT-proBNP, IVC maximum diameter and RAP. Other echocardiographic parameters including left ventricular (LV) systolic function and LV filling pressures were considered.

Results

An exponential inverse relationship was found between NT-pro-BNP levels at admission with levels decreasing progressively with the increment of the ratio (Group I: 12828±10600 ng/l; Group II 5549±5383 ng/l; Group III 3695±3870 ng/l; p=0.004) (Figure 1a). An analogous correlation was observed when considering the IVC maximum diameter (Group I: 20.87±5.37 mm; Group II 18.08±4.35 mm; Group III 10.9±3.36 mm; p<0.001) (Figure 1b) and the RAP estimated at echocardiography (Group I: 12.875±5.25 mmHg; Group II 9.157±4.82 mmHg; Group III 4±1.61 mmHg; p<0.001) (Figure 1c).

In addition, progressively increasing values of LVEF (Group I: 28±11.3%; Group II 42±17.3%; Group III 49±11.8%; p=0.001) were detected from the lowest to the highest TAPSE/PASP tertiles. No correlation was observed in the three groups for E/E' values at admission (Group I: 17.17±6.7; Group II 19.42±8.36; Group III 15.92±5.7; p=0.5).

Figure 1

Conclusions

In ADHF, the association between RV to Pc uncoupling, echo-derived measures of congestion and natriuretic peptide levels is here described for the first time. The extent of RV dysfunction in ADHF deserves attention and seems to represent a critical and quite underestimated key mechanism between congestion resolution and in-hospital worsening HF.

4306Hemodynamic correlates of tricuspid annular pulmonary systolic excursion (TAPSE)/systolic pulmonary arterial pressure (SPAP) ratio in heart failure with reduced ejection fraction

Background

The TAPSE/SPAP ratio has gained a role as an easy-to-use surrogate of right ventricle-to-pulmonary circulation (RV-PC) coupling, showing a strong prognostic significance in heart failure (HF) patients. The hemodynamic determinants of TAPSE/SPAP ratio, as assessed by invasive approach, have not been fully elucidated.

Aim

To identify the right heart hemodynamic variables correlated with TAPSE/SPAP in a HF with reduced EF (HFrEF) cohort, at rest and during exercise.

Methods

24 HFrEF patients (age 67±11 years LV EF 27±7) underwent to rest and exercise echocardiography and performed right heart catheterization within 24 hours. Bivariate correlations between TAPSE/SPAP ratio (at rest and exercise), right heart hemodynamic variables, RV systolic function and NTproBNP have been explored.

Results

TAPSE/SPAP ratio at rest showed a moderate correlation with pulmonary artery wedge pressure (PAWP: r=0.432; p=0.039), pulmonary artery pressures (PAP systolic: r=0.474; p=0.026; PAP diastolic: r=0.434; p=0.043; mPAP: r=0.476; p=0.025), pulmonary vascular resistance and compliance (r=0.475; p=0.041), while a stronger correlation was identified with right atrial (RAP systolic: r=0.571; p=0.017; RAP diastolic: r=0.675; p=0.006) and right ventricular pressures- in particular diastolic ones (RVP systolic: r=0.584; p=0.004; RAP diastolic: r=0.646; p=0.002). No significant correlation was found with NTproBNP and RV 3D EF. Exercise TAPSE/SPAP ratio significantly correlated with right atrium (RAP systolic: r=0.564; p=0.036) and right ventricle systolic pressures only (RVP systolic: r=0.765; p<0.001).

TAPSE/PAPS correlation graphics

Conclusions

TAPSE/SPAP ratio at rest showed a stronger correlation with invasively derived diastolic right heart pressure rather than pulmonary vascular bed pressures. A similar correlation was also observed for exercise TAPSE/SPAP ratio. This tight correlation with RV, rather than vascular pressures, supports the significance of the ratio as a marker of RV adaptation to vascular overload.