Systemic vascular dysfunction is associated with emphysema burden in mild COPD.

BACKGROUND: Cardiovascular diseases play a major role in morbidity and mortality in the earlier stages of COPD. We hypothesized that systemic vascular dysfunction would be present even in patients who are currently considered at "low-risk" for negative cardiovascular outcomes, i.e., those with largely preserved FEV1 , few exacerbations and only mild burden of respiratory symptoms (GOLD spirometric grade 1, clinical group A).

METHODS: 16 patients (FEV1  = 86 ± 13%) and 16 age- and gender-matched controls underwent measurements of: a) central arterial stiffness by pulse wave velocity, b) brachial flow-mediated dilation and c) forearm muscle oxygenation by near-infrared spectroscopy. Computed tomography quantified emphysema (% of low attenuation areas (LAA)) and airway disease.

RESULTS: Patients and controls were well matched for key clinical variables including co-morbidities burden. Thirteen patients presented with more than 5% LAA: emphysema extension was negatively related to transfer factor for carbon monoxide (TLCO ) (r = -0.63; p = .01). Compared to controls, patients had higher central arterial stiffness, lower normalized (to shear stress) flow-mediated dilation, delayed time to peak flow-mediated dilation and poorer muscle oxygenation (p < .05). TLCO and emphysema, but not airway disease, were significantly related to each of these functional abnormalities (r values ranging from 0.51 to 0.66; p < .05).

CONCLUSION: Systemic vascular dysfunction is present in the earlier stages of COPD, particularly in patients with greater emphysema burden and low TLCO . Regardless FEV1 , patients showing those structural and functional abnormalities might be at higher risk of negative events thereby deserving closer follow-up for early detection of cardiovascular disease.