Patterns of pulmonary function and mortality in chronic heart failure, results from the MyoVasc study

Background

Preclinical evidence suggests that pulmonary fibrosis due to left heart disease may represent end-organ damage in heart failure (HF). Vice versa, decreased pulmonary function is related to worsening of heart failure in the absence of obstructive airway pattern.

Purpose

This study investigated the relationship between patterns of pulmonary function (i.e. obstruction and restriction) and mortality in chronic HF.

Methods

For the present analysis data from the MyoVasc-study (N=3,289) were analysed. During a five-hour examination in the dedicated study center, systematic phenotyping was performed in a highly standardized setting. Chronic HF was defined as American Heart Association HF Stage C/D. Information on pulmonary function was assessed via body plethysmography (MasterScreen Body, Carefusion, Germany). Participants with forced expiratory ratio <0.7 or COPD were categorized as obstructive, while restriction was defined as reduction in total lung capacity. Information on vital status was obtained via registration offices.

Results

The analysis sample comprised 1,509 individuals with chronic heart failure and information on pulmonary function, of whom 286 had HF with reduced ejection fraction (HFrEF), 559 HF with preserved ejection fraction (HFpEF), and 333 HFpEFborderline. The mean age was 64.6±11.3 years, 38.7% were female. In the sample 124 subjects had pulmonary restriction and 400 individuals had an obstruction. During a median time to follow up of 3.70 (inter quartile range 1.25 to 4.00) years, death occurred in 170 individuals. Among clusters of pulmonary function most participants died in the restriction group (25.0%), followed by pulmonary obstruction (12.2%) and normal pulmonary function (7.3%, P for trend <0.001). Cox- regression analysis adjusted for age, sex and height revealed pulmonary restriction (hazard ratio (HR) 3.00 [95% confidence interval 2.04–4.42], P<0.001] and obstruction (HR 1.61 [1.11–2.35], P=0.01) as predictors of all-cause death. After additional controlling for traditional cardiovascular risk factors and the clinical profile only pulmonary restriction remained an independent predictor of mortality (HRrestriction 2.12 [1.50–3.43]; P=0.002; HRobstruction 1.35 [0.91–2.00]; P=0.10). Among HF phenotypes obstruction was only in individuals with HFpEF an independent predictor of all-cause death (HRHFpEF 2.60 [1.29–5.23]; P=0.007; HRHFpEFborderline 1.58 [0.70–3.57]; P=0.27; HRHFrEF 0.96 [0.52–1.78]; P=0.90), while pulmonary restriction was found to be predictive for death only in subjects with HFpEFborderline (HRHFpEF 2.15 [0.70–6.64]; P=0.18; HRHFpEFborderline: HR 5.47 [2.56–11.68]; P<0.001; HRHFrEF 1.74 [0.88–3.46]; P=0.11)

Conclusion

In chronic heart failure, pulmonary restriction was a stronger predictor of mortality than obstructive airway pattern. The present analysis supports the hypothesis of pulmonary fibrosis as end-organ damage in HF, and may potentially represent a therapeutic target.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): German Center for Cardiovascular Research (DZHK)

Global longitudinal strain predicts outcome in chronic heart failure across American Heart Association stages: results from the MyoVasc study

Background

Global longitudinal strain (GLS) demonstrated a superior prognostic value over left ventricular ejection fraction (LVEF) in acute heart failure (HF). Its prognostic value across American Heart Association (AHA) stages of HF – especially under considering of conventional echocardiographic measures of systolic and diastolic function – has not yet been comprehensively evaluated.

Purpose

To evaluate the prognostic value of GLS for HF-specific outcome across AHA HF stages A to D.

Methods

Data from the MyoVasc-Study (n=3,289) were analysed. Comprehensive clinical phenotyping was performed during a five-hour investigation in a dedicated study centre. GLS was measured offline utilizing QLab 9.0.1 (PHILIPS, Germany) in participants presenting with sinus rhythm during echocardiography. Worsening of HF (comprising transition from asymptomatic to symptomatic HF, HF hospitalization, and cardiac death) was assessed during a structured follow-up with subsequent validation and adjudication of endpoints. AHA stages were defined according to current guidelines.

Results

Complete information on GLS was available in 2,400 participants of whom 2,186 categorized to AHA stage A to D were available for analysis. Overall, 434 individuals were classified as AHA stage A, 629 as stage B and 1,123 as stage C/D. Mean GLS increased across AHA stages of HF: it was lowest in stage A (−19.44±3.15%), −18.01±3.46% in stage B and highest in AHA stage C/D (−15.52±4.64%, P for trend <0.0001). During a follow-up period of 3.0 [1.3/4.0] years, GLS denoted an increased risk for worsening of HF after adjustment for age and sex (hazard ratio, HRGLS [per standard deviation (SD)] 1.97 [95% confidence interval 1.73/2.23], P<0.0001) in multivariable Cox regression analysis. After additional adjustment for cardiovascular risk factors, clinical profile, LVEF and E/E' ratio, GLS was the strongest echocardiographic predictor of worsening of HF (HRGLS [per SD] 1.47 [1.20/1.80], P=0.0002) in comparison to LVEF (HRLVEF [per SD] 1.23 [1.02/1.48], P=0.031) and E/E' ratio (HRE/E' [per SD] 1.12 [0.99/1.26], P=0.083). Interestingly, when stratifying for AHA stages, GLS denoted a similar increased risk for worsening of HF in individuals classified as AHA stage A/B (HRGLS [per SD] 1.63 [1.02/2.61], P=0.039) and in those classified as AHA stage C/D (HRGLS [per SD] 1.95 [1.65/2.29], P<0.0001) after adjustment for age and sex. For further evaluation, Cox regression models with interaction analysis indicated no significant interaction for (i) AHA stage A/B vs C/D (P=0.83) and (ii) NYHA functional class <II vs ≥II in individuals classified as AHA stage C/D (P=0.12).

Conclusions

GLS demonstrated a higher predictive value for worsening of HF than conventional echocardiographic measures of systolic and diastolic function. Interestingly, GLS indicated an increased risk for worsening of HF across AHA stages highlighting its potential value to advance risk prediction in chronic HF.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): German Center for Cardiovascular Research (DZHK), Center for Translational Vascular Biology (CTVB) of the University Medical Center of the Johannes Gutenberg-University Mainz