Aortic strain during acute exacerbations of chronic obstructive pulmonary disease and at recovery.

RATIONALE: Aortic stiffness is a key determinant of cardiovascular morbidity and mortality. Acute Exacerbations of COPD (AECOPD) are accompanied by a spike in systemic stiffness. We investigated an important constituent of systemic stiffness, aortic strain (AS), in a prospective observational cohort study of patients admitted to our tertiary Australian centre with doctordiagnosed AECOPD. The primary hypothesis was that AS would be increased at exacerbation in comparison to recovery, and the secondary hypothesis was that AS would be associated with clinical and biochemical parameters. METHOD(S): 67 individuals underwent dynamic ECG-gated 256-multidetector CT, firstly during hospitalisation for AECOPD and secondly following discharge when clinically recovered. Ascending aortic cross-sectional area was measured at 10% ECG R-R interval reconstructions at the ascending aorta mid-point (mid-way between aortic valve and brachiocephalic trunk). AS was calculated as (maximum area-minimum area)/minimum area and expressed as percentage. Paired t-tests and Pearson correlations were used for analysis. RESULT(S): AS was higher at AECOPD compared to recovery (10.2+/-6.4% vs 8.3+/-4.2%, mean+/-SD, p=0.01). AS was negatively correlated with age (r=-0.434, p<0.001). AS was not associated with FEV1, diffusing capacity, emphysema index, left ventricular ejection fraction, coronary artery calcium score, troponin, b-type natriuretic peptide, length of stay, heart rate, modified Medical Research Council dyspnoea score, Charlson Comorbidity Index or COPD Assessment Test. CONCLUSION(S): AS is higher during AECOPD than at recovery. However, it was not associated with other measures of disease and comorbidities beyond that of older age. Our findings suggest that complex mechanisms govern vascular stiffness in COPD; processes that are amplified during AECOPD.