Target renal damage: the microvascular associations of increased aortic stiffness in patients with COPD

Abstract

BackgroundAlthough renal impairment has been described in COPD, there is opportunity to evaluate further to determine nature and consider optimal management. Increased aortic stiffness, as seen in COPD, leads to reduced buffering of pulsatile flow. We hypothesised that urinary albumin creatinine ratio (UACR) would reflect glomerular damage related to aortic stiffness.MethodsPatients with COPD and controls underwent spirometry, blood pressure, arterial stiffness - aortic pulse wave velocity (PWV) and provided a spot urine sample for UACR, with other renal biomarkers measured.ResultsThe UACR was increased in patients (n = 52): 0.80 mg/mmol compared to controls (n = 34): 0.46 mg/mmol, p < 0.05. Aortic PWV was related to log10 UACR in all subjects (r = 0.426, p < 0.001) and COPD patients alone. Aortic PWV was a significant variable for UACR with oxygen saturations, after accounting for potential confounders. Eight subjects (7 patients) reached a defined clinical microalbuminuria threshold, with aortic PWV greater in these patients compared to those patients without, although albuminuria is a continuum. Proximal tubular damage biomarkers, unlike the glomerular marker, were not different between patients and controls.ConclusionsThere is glomerular damage in patients with COPD evidenced by increased UACR, related to increased aortic stiffness. Besides the macrovascular prognostic implications of increased aortic stiffness, the microvascular state in COPD management should be considered.

Cardiovascular and inflammatory effects of simvastatin therapy in patients with COPD: a&nbsp;randomized controlled trial

“…Aortic PWV measurements were comparable with those in recently published studies of patients with COPD, 27 , 28 but lower than initial reports of around 11 m/sec despite these original COPD studies using similar methodology and devices. 10 , 11 Age, lung function, and cholesterol levels in our patients were similar to other studies in COPD, and our exclusion of comorbidities was also comparable.…”

“… 10 , 11 Age, lung function, and cholesterol levels in our patients were similar to other studies in COPD, and our exclusion of comorbidities was also comparable. 10 , 27 , 28 As expected, multiple linear regression demonstrated that seated MAP and age were predictors of baseline aortic PWV, which is reassuring given that age and MAP are major contributors to aortic PWV, 20 but interestingly, aortic PWV was not associated with baseline cholesterol.…”

Association Between Pulse Wave Velocity and a Marker of Renal Tubular Damage (N‐Acetyl‐β‐D‐Glucosaminidase) in Patients Without Diabetes

“…To our knowledge, only a single recent study has investigated the association between PWV and renal markers of tubular damage . In this study of smokers with and without chronic obstructive pulmonary disease (COPD), aortic PWV was found to be independently related to urinary levels of albumin in patients with COPD but was not related to urinary levels of either NGAL or KIM‐1 in all patients or in those with COPD.…”

Study of Microalbuminuria in Patients with Stable COPD

“…[4] John M et al studied that COPD patients have increased UACR compared to controls (asymptomatic smokers) which was related to increased aortic stiffness measured by aortic pulse wave velocity (PWV). [9] In our study unlike above mentioned study included COPD patients without any coexisting comorbidities like renal disease, IHD, hypertension and diabetes. We found that in patients with cor-pulmonale or pulmonary hypertension MAB levels were the highest.…”