Genetic evidence for a causative effect of airflow obstruction on left ventricular filling: a Mendelian randomisation study

• Published in: Respiratory research Vol. 22; no. 1; p. 199
• Main Authors: Harbaum, Lars, Hennigs, Jan K, Simon, Marcel, Oqueka, Tim, Watz, Henrik, Klose, Hans
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 07.07.2021; BioMed Central; BMC
• Subjects: Air flow; Annotations; Biobanks; Blood-vessels; Cohort Studies; Confidence intervals; Consortia; Environmental risk; Estimates; Forced Expiratory Volume - physiology; Genetic aspects; Genetic diversity; Genetic variance; Genome-Wide Association Study - methods; Genomes; Health risk assessment; Heart; Humans; Left ventricular function; Lungs; Magnetic resonance imaging; Mendelian Randomization Analysis - methods; Meta-analysis; Observational studies; Pleiotropy; Polymorphism, Single Nucleotide - genetics; Population; Population genetics; Population studies; Pulmonary circulation; Pulmonary Disease, Chronic Obstructive - diagnosis; Pulmonary Disease, Chronic Obstructive - genetics; Pulmonary Disease, Chronic Obstructive - physiopathology; Randomization; Risk analysis; Risk factors; Sensitivity analysis; Software; Statistical analysis; Statistical methods; Variance; Ventricle; Ventricular Function, Left - physiology; Vital Capacity - physiology; Germany; United Kingdom > UK
• ISSN: 1465-993X; 1465-9921; 1465-993X; 1465-9921
• DOI: 10.1186/s12931-021-01795-9

Observational studies on the general population have suggested that airflow obstruction associates with left ventricular (LV) filling. To limit the influence of environmental risk factors/exposures, we used a Mendelian randomisation (MR) approach based on common genetic variations and tested whether a causative relation between airflow obstruction and LV filling can be detected. We used summary statistics from large genome-wide association studies (GWAS) on the ratio of forced expiratory volume in 1 s to forced vital capacity (FEV1/FVC) measured by spirometry and the LV end-diastolic volume (LVEDV) as assessed by cardiac magnetic resonance imaging. The primary MR was based on an inverse variance weighted regression. Various complementary MR methods and subsets of the instrument variables were used to assess the plausibility of the findings. We obtained consistent evidence in our primary MR analysis and subsequent sensitivity analyses that reducing airflow obstruction leads to increased inflow to the LV (odds ratio [OR] from inverse variance weighted regression 1.05, 95% confidence interval [CI] 1.01-1.09, P = 0.0172). Sensitivity analyses indicated a certain extent of negative horizontal pleiotropy and the estimate from biased-corrected MR-Egger was adjusted upward (OR 1.2, 95% CI 1.09-1.31, P < 0.001). Prioritisation of single genetic variants revealed rs995758, rs2070600 and rs7733410 as major contributors to the MR result. Our findings indicate a causal relationship between airflow obstruction and LV filling in the general population providing genetic context to observational associations. The results suggest that targeting (even subclinical) airflow obstruction can lead to direct cardiac improvements, demonstrated by an increase in LVEDV. Functional annotation of single genetic variants contributing most to the causal effect estimate could help to prioritise biological underpinnings.