Impaired peripheral circulation in lower-leg arteries caused by higher arterial stiffness and greater vascular resistance associates with nephropathy in type 2 diabetic patients with normal ankle-brachial indices

The risk factors for calcification vary among the different sections of the lower extremity artery in patients with symptomatic peripheral arterial disease

BACKGROUND

Peripheral arterial disease (PAD) is associated with considerable mortality and morbidity worldwide. The present study explored the risk factors for arterial calcification among the different sections of the lower extremity in patients with PAD and analyzed their correlations with the extent of arterial stenosis at the corresponding section.

METHODS

This study enrolled symptomatic PAD patients from our hospital from March 2017 to March 2018. The lower extremity arterial calcification score (LEACS) and lower extremity arterial stenosis index (LEASI), representing the extent of arterial stenosis, were measured on computed tomography (CT) and the correlations between them were analyzed using Spearman's correlation analysis. The relationships between risk factors and calcification were analyzed among the different sections of the lower extremity artery.

RESULTS

In total, 209 patients were included. The LEACSs of the total lower extremity, aortoiliac artery, and femoropopliteal and infrapopliteal arteries were correlated with the LEASI (all P < 0.05), but their correlation was relatively weak in the aortoiliac artery. Univariate analysis showed that hypertension was associated with the total (P = 0.019) and aortoiliac (P = 0.012) LEACSs. Diabetes was related to both femoropopliteal (P = 0.001) and infrapopliteal (P = 0.002) LEACSs. The infrapopliteal LEACS was higher in male patients (P = 0.011). After adjustment for age, the above relationships were maintained among the different sections, but not in the total lower extremity artery.

CONCLUSIONS

The LEACS is associated with the LEASI in all arterial sections, but that of the aortoiliac artery was relatively weak. Different factors have different effects on calcification among the various sections of the lower extremity artery.

Relationships between chronic comorbidities and the atherosclerosis indicators ankle-brachial index and brachial-ankle pulse wave velocity in patients with type 2 diabetes mellitus

This study aimed to determine associations between ankle-brachial index (ABI) and brachial-ankle pulse wave velocity (baPWV) with different comorbidities in patients with type 2 diabetes mellitus (DM). Records of patients with type 2 DM who received an ABI and baPWV examination between August 2013 and February 2015 were retrospectively reviewed. Associations of ABI and baPWV with chronic kidney disease (CKD), chronic liver disease (CLD), coronary artery disease (CAD) and diabetic nephropathy (DN) were examined by regression analysis. A total of 1232 patients (average age, 65.1±10.0 years) were included in the analysis. CKD and DN were associated with low ABI and increased baPWV (all, P<0.001). No associations were found between CAD and CLD and ABI or baPWV. Thus, regression analysis was performed for CKD and DN. Low ABI was associated with risk of CKD in the crude model (OR 0.724, 95% CI 0.648 to 0.808, P<0.001) and adjusted model (OR 0.872, 95% CI 0.762 to 0.999, P=0.048), whereas baPWV was only significant in the crude model (OR 1.199, 95% CI 1.112 to 1.294, P<0.001). Low ABI was associated with risk of DN in the crude model (OR 0.873, 95% CI 0.780 to 0.977, P=0.018) and adjusted model (OR 0.884, 95% CI 0.782 to 0.999, P=0.048). No association was found for baPWV. In conclusion, low ABI was associated with risk of CKD and DN in patients with type 2 diabetes.

Association of arterial calcification with chronic limb ischemia in patients with peripheral artery disease

OBJECTIVE

Arterial calcification is associated with an increased risk of limb events, including amputation. The association between calcification in lower extremity arteries and the severity of ischemia, however, has not been assessed. We thus sought to determine whether the extent of peripheral artery calcification (PAC) was correlated with Rutherford chronic ischemia categories and hypothesized that it could independently contribute to worsening limb status.

METHODS

We retrospectively reviewed all patients presenting with symptomatic peripheral artery disease who underwent evaluation by contrast and noncontrast computed tomography scan of the lower extremities as part of their assessment. Demographic and cardiovascular risk factors were recorded. Rutherford ischemia categories were determined based on history, physical examination, and noninvasive testing. PAC scores and the extent of occlusive disease were measured on noncontrast and contrast computed tomography scans, respectively. Spearman's correlation testing was used to assess the relationship between occlusive disease and calcification scores. Multivariable logistic regression was used to identify factors associated with increasing Rutherford ischemia categories.

RESULTS

There were 116 patients identified, including 75 with claudication and 41 with critical limb ischemia. In univariate regression, there was a significant association between increasing Rutherford ischemia category and age, diabetes duration, hypertension, the occlusion score, and PAC. There was a moderate correlation between the extent of occlusive disease and PAC scores (Spearman's R = 0.6). In multivariable analysis, only tobacco use (odds ratio [OR], 3.1; 95% confidence interval [CI], 1.2-8.3), diabetes duration (OR, 1.04; 95% CI, 1.01-1.08), and the calcification score (OR, 2.1; 95% CI, 1.4-3.2) maintained an association with increasing ischemia categories after adjusting for relevant cardiovascular risk factors and the extent of occlusive disease.

CONCLUSIONS

PAC is independently associated with increased ischemia categories in patients with peripheral artery disease. Further research aimed at understanding the relationship between arterial calcification and worsening limb ischemia is warranted.

Brachial-ankle pulse wave velocity, but not ankle-brachial index, predicts all-cause mortality in patients with diabetes after lower extremity amputation

We examined whether brachial‐ankle pulse wave velocity (baPWV) and ankle‐brachial pressure index (ABI) are predictors for mortality in diabetic patients after lower extremity amputation. This was an observational historical cohort study of 102 Japanese diabetic patients after first non‐traumatic lower extremity amputation, with a mean age of 63 years (standard deviation 12 years). The end‐point was all‐cause mortality. During the mean follow‐up period of 3.3 years, 44 patients reached the end‐point. In both univariate and multivariate analyses, baPWV (m/s) (hazard ratio [HR] 1.05 and 1.04, both P < 0.01, respectively), but not ABI (HR 0.38 and 0.89, P = 0.08 and 0.86, respectively), was a significant predictor for the end‐point. When baPWV (above or below the median [21.8 m/s]) and ABI (normal [0.9–1.4] or not) were analyzed as categorical variables, the results were similar. In conclusion, baPWV, but not ABI, might be a predictor for all‐cause mortality in diabetic patients after lower extremity amputation.

Arterial calcification and bone physiology: role of the bone-vascular axis

Bone never forms without vascular interactions. This simple statement of fact does not adequately reflect the physiological and pharmacological implications of the relationship. The vasculature is the conduit for nutrient exchange between bone and the rest of the body. The vasculature provides the sustentacular niche for development of osteoblast progenitors and is the conduit for egress of bone marrow cell products arising, in turn, from the osteoblast-dependent haematopoietic niche. Importantly, the second most calcified structure in humans after the skeleton is the vasculature. Once considered a passive process of dead and dying cells, vascular calcification has emerged as an actively regulated form of tissue biomineralization. Skeletal morphogens and osteochondrogenic transcription factors are expressed by cells within the vessel wall, which regulates the deposition of vascular calcium. Osteotropic hormones, including parathyroid hormone, regulate both vascular and skeletal mineralization. Cellular, endocrine and metabolic signals that flow bidirectionally between the vasculature and bone are necessary for both bone health and vascular health. Dysmetabolic states including diabetes mellitus, uraemia and hyperlipidaemia perturb the bone-vascular axis, giving rise to devastating vascular and skeletal disease. A detailed understanding of bone-vascular interactions is necessary to address the unmet clinical needs of an increasingly aged and dysmetabolic population.

Exercise attenuates the premature cardiovascular aging effects of type 2 diabetes mellitus

Type 2 diabetes mellitus (T2D) is an example of a disease process that results in decrements in function additional to those imposed by the inexorable 'primary aging' process. These decrements due to disease, rather than primary aging, can be termed 'secondary aging', and include the premature development (as early as adolescence) of asymptomatic preclinical cardiovascular abnormalities (e.g. endothelial dysfunction, arterial stiffness, diastolic dysfunction), as well as impaired exercise performance. These abnormalities are important, as they are associated with greater cardiovascular morbidity and mortality in people with and without T2D. A better understanding of the pathophysiology of secondary cardiovascular aging in people with T2D is warranted, and an evaluation of the benefits of existing treatments for these abnormalities is useful (e.g. exercise training). The focus of this review is to discuss the data relevant to the following key postulates: (a) T2D causes premature cardiovascular aging; (b) in contrast to primary cardiovascular aging, the premature cardiovascular aging of T2D may be modifiable with exercise. The exercise-focused perspective for this review is appropriate because impairments in exercise performance are markers of premature cardiovascular aging in T2D, and also because exercise training shows promise to attenuate some aspects of cardiovascular aging during the preclinical stage.

The Association Between Ankle Brachial Pressure Index and Pulse Wave Velocity: Clinical Implication of Pulse Wave Velocity

Objective: The aim of this study was to assess the relationship between ankle brachial pressure index and pulse wave velocity in patients with peripheral arterial disease.

Methods: Brachial-knee and brachial-ankle pulse wave velocity were measured by pneumoplethysmography using cuffs in a standard technique. Correlation between pulse wave velocity and Doppler-ankle brachial pressure index was assessed by Spearman correlation and receiver operating curves.

Results: A total of 133 claudicants were assessed. Analysis by developing receiver operating curves for ankle brachial pressure index and pulse wave velocity showed that patients with ankle brachial pressure index over 0.6 were more likely to have a bk-pulse wave velocity over 9.2 m/s and ba-pulse wave velocity over 9.5 m/s.

Conclusion: These results show for the first time that nondiabetic vascular patients may have measurable significant arterial stiffness independent of an impaired ankle brachial pressure index. These data suggest that pulse wave velocity may be valuable in screening and evaluating the severity of peripheral arterial disease.