Association between chronic obstructive pulmonary disease and all-cause mortality after aortic valve replacement for aortic stenosis

Abstract

Introduction Chronic obstructive pulmonary disease (COPD) and aortic stenosis (AS) are the most common diseases in aging population that their prevalence and percental change in mortality increase over the years. In severe AS, aortic valve replacement (AVR) is the only treatment that has demonstrated to improve survival, however the presence of comorbidities increases the operative risk and influences negatively on the outcomes after AVR. Therefore, the definition of COPD varies across the studies and is not always based on the use of pulmonary functional tests. Accordingly, the aim of the present study is to evaluate the association between pulmonary functional parameters and all-cause mortality after AVR in a large cohort of patients with severe AS. Methods Total of 400 patients (78.0 year-old, 56.7% men) with severe AS and documented preoperative pulmonary functional test (PFT) were retrospectively analyzed. Demographic and clinical characteristics were collected from electronic medical records while echocardiography was performed and measured according to the recommendations. PFTs were performed prior to AVR and categories defined in the Society of Thoracic Surgeons (STS) Adult Cardiac Surgery Database: normal pulmonary function was defined by an FEV1 >75% of predicted; mild COPD if FEV1 was 60–75% of predicted; moderate COPD if FEV1 was 50–59% of predicted and severe COPD when FEV1 <50% of predicted. Results Mild, moderate and severe COPD were documented in 75 (19%), 31 (8%) and 22 (5%) while the remaining 68% had normal PFTs. Patients with moderate and severe COPD had significantly larger LV mass and LV end-systolic volume whereas LV ejection fraction was significantly lower. The FVC, FEV1, Tiffeneau index, VC, PEF, and IC were the worst among patients with moderate and severe COPD (per definition) (p<0.0001). Over a median follow-up of 32 months, 92 (23%) patients died. The survival rates were significantly lower in patients with moderate and severe COPD (Log rank p=0.003, Figure 1). In multivariable Cox regression analysis, some clinical factors and COPD were independently associated with all-cause mortality (table 1). Remarkably, any grade of COPD was associated with 2-fold increased risk of all cause-mortality (HR 1.933; 95% CI 1.166–3.204; p=0.011 for mild COPD and HR 2.028; 95% CI 1.154–3.564; p=0.014 for moderate/ severe COPD, separately). Conclusion Patients with moderate and severe COPD had higher LV hypertrophy and reduced LV ejection fraction while PFT parameters were the worst among these patients. The survival rates were significantly lower in patients with moderate and severe COPD compared with patients without COPD. In addition to other clinical factors, any grade of COPD was associated with 2-fold increased risk of all cause-mortality. Funding Acknowledgement Type of funding sources: None.