Clinical performance and exercise hemodynamics in patients with severe secondary tricuspid regurgitation and chronic atrial fibrillation

Lymphatic morphology and function in chronic right heart failure due to secondary tricuspid valve regurgitation

BACKGROUND

In heart failure, the capacity of the lymphatic system dictates symptoms of circulatory congestion. This study aimed at describing structural and functional changes of the lymphatic system in patients with chronic right-sided heart failure.

METHODS

Individuals with long-standing severe tricuspid valve regurgitation and symptoms of heart failure were compared with age- gender- and weight-matched controls. Lymphatic structure and function were examined using non-contrast MR lymphangiography and near-infrared fluorescence imaging. Microvascular fluid dynamics and distribution were evaluated using strain gauge plethysmography and bio-impedance.

RESULTS

In total nine patients and nine controls were included. Lymphatic morphology was unchanged in cases compared to controls with similar thoracic duct diameters 3.1(2.1-3.5) mm vs. 2.0(1.8-2.4) mm (p-value = 0.11), similar lymphatic classifications (p-value 0.34), and an identical number of lymphatic vessels in the legs 6 ± 1 vs. 6 ± 3 vessels/field (p-value = 0.72). Lymphatic function was comparable with contraction frequencies of 0.5 ± 0.2 and 0.5 ± 0.3 /min (p-value = 0.52) and a maximal lymphatic pumping pressure of 60 ± 13 and 57 ± 12 mmHg (p-value = 0.59) for cases and controls respectively. Finally, microvascular capillary filtration, isovolumetric threshold, and fluid distribution were similar between groups (p-value≥0.16 for all comparisons).

CONCLUSION

In this small exploratory study, individuals with severe secondary tricuspid valve regurgitation and right-sided heart failure displayed a largely similar lymphatic anatomy and function. Thoracic duct diameter displayed a trend towards increased size in the patient group. We speculate that cases were indeed stable and optimally treated at the time of examination, and with a lymphatic system largely unaffected by any of the current or prior hemodynamic changes.

Myocardial work across different etiologies of right ventricular dysfunction and healthy controls

Evaluating right ventricular (RV) function remains a challenge. Recently, novel echocardiographic assessment of RV myocardial work (RVMW) by non-invasive pressure-strain loops was proposed. This enables evaluation of right ventriculoarterial coupling and quantifies RV dyssynchrony and post-systolic shortening. We aimed to assess RVMW in patients with different etiologies of RV dysfunction and healthy controls. We investigated healthy controls (n=17), patients with severe functional tricuspid regurgitation (FTR; n=22), and patients with precapillary pulmonary hypertension (PCPH; n=20). Echocardiography and right heart catheterization were performed to assess 1) RV global constructive work (RVGCW; work needed for systolic myocardial shortening and isovolumic relaxation), 2) RV global wasted work (RVGWW; myocardial shortening following pulmonic valve closure), and 3) RV global work efficiency (RVGWE; describes the relation between RV constructive and wasted work). RVGCW correlated with invasive RV stroke work index (r=0.66, P<0.001) and increased in tandem with higher afterload, i.e., was low in healthy controls (454±73 mmHg%), moderate in patients with FTR (687±203 mmHg%), and highest among patients with PCPH (881±255 mmHg%). RVGWE was lower and RVGWW was higher in patients with FTR (86±8% and 91 mmHg% [53-140]) or PCPH (86±10% and 110 mmHg% [66-159]) as compared with healthy controls (96±3% and 10 mmHg%). RVMW by echocardiography provides a promising index of RV function to discriminate between patients with RV volume or pressure overload. The prognostic value of this measure needs to be settled in future studies.

Exercise MR-proANP unmasks latent right heart failure in CTEPH

OBJECTIVE

The present study was designed to investigate the dynamics of right atrial pressure (RAP) and mid-regional pro-atrial natriuretic peptide (MR-proANP) during physical exercise in patients with chronic thromboembolic pulmonary hypertension (CTEPH) and to determine whether these parameters might serve as a tool to measure exercise-dependent atrial stress as an indicator of right heart failure.

METHODS

This prospective observational cohort study included 100 CTEPH patients who underwent right heart catheterization during physical exercise (eRHC). Blood samples for MR-proANP measurement were taken prior, during, and after eRHC. MR-proANP levels were correlated to RAP levels at rest, at peak exercise (eRAP), and during recovery. RAP at rest ≤7 mmHg was defined as normal and eRAP >15 mmHg as suggestive of right heart failure.

RESULTS

During eRHC mean RAP increased from 6 mmHg (standard deviation, SD 4) to 16 mmHg (SD 7; p < 0.001). MR-proANP levels and dynamics correlated with RAP at rest (r_s = 0.61; p < 0.001) and at peak exercise (r_s = 0.66; p < 0.001). Logistic regression analysis revealed the peak MR-proANP level (B = 0.058; p = 0.004) and the right atrial area (B = 0.389; p < 0.001) to be associated with eRAP dynamics. A peak MR-proANP level ≥139 pmol/L (AUC = 0.81) and recovery level ≥159 pmol/L (AUC = 0.82) predicted an eRAP >15 mmHg. Physical exercise unmasked right heart failure in 39% of patients with normal RAP at rest; these patients were also characterized by a more distinct increase in MR-proANP levels (p = 0.005) and higher peak (p < 0.001) and recovery levels (p < 0.001).

CONCLUSIONS

RAP and MR-proANP dynamics unmask manifest and latent right heart failure in CTEPH patients.