Proximal superficial femoral artery occlusion, collateral vessels, and walking performance in peripheral artery disease

Multi-Modality Imaging of Atheromatous Plaques in Peripheral Arterial Disease: Integrating Molecular and Imaging Markers

Peripheral artery disease (PAD) is a common and debilitating condition characterized by the narrowing of the limb arteries, primarily due to atherosclerosis. Non-invasive multi-modality imaging approaches using computed tomography (CT), magnetic resonance imaging (MRI), and nuclear imaging have emerged as valuable tools for assessing PAD atheromatous plaques and vessel walls. This review provides an overview of these different imaging techniques, their advantages, limitations, and recent advancements. In addition, this review highlights the importance of molecular markers, including those related to inflammation, endothelial dysfunction, and oxidative stress, in PAD pathophysiology. The potential of integrating molecular and imaging markers for an improved understanding of PAD is also discussed. Despite the promise of this integrative approach, there remain several challenges, including technical limitations in imaging modalities and the need for novel molecular marker discovery and validation. Addressing these challenges and embracing future directions in the field will be essential for maximizing the potential of molecular and imaging markers for improving PAD patient outcomes.

Comparison of complete multi-level vs. iliac-only revascularization for concomitant iliac and superficial femoral artery occlusive disease

Objective

The aim of this study is to compare the efficacy and safety of complete multi-level vs. iliac-only revascularization for the treatment of concomitant iliac and superficial femoral artery (SFA) occlusive disease.

Methods

A total of 139 consecutive adult patients with severe stenosis and occlusive iliac and SFA disease with Rutherford categories 2-5 underwent multi-level (n = 71) and iliac-only (n = 68) revascularization at the Department of Intervention Vascular Surgery, Peking University Third Hospital, and Aerospace Center Hospital, between March 2015 and June 2017. Improvement in Rutherford class, perioperative major adverse events, the length of stay, survival rate, and limb salvage rate were assessed. The neutrophil-lymphocyte ratio and platelet-lymphocyte ratio were compared between the two groups.

Results

At 48 months, improvement in the Rutherford category was observed in the two groups with no significant difference (P = 0.809). Additionally, the two groups were similar concerning the primary patency (84.0% vs. 79.1%, P = 0.717) and limb salvage rate (93.1% vs. 91.3%, P = 0.781). A higher proportion of the perioperative major adverse events (33.8% vs. 27.9%, P = 0.455), the all-cause mortality (11.3% vs. 8.8%, P = 0.632), and the average length of hospital stay [7.0 (6.0, 11.0) vs. 7.0 (5.0, 8.0), P = 0.037] were seen in the multi-level group compared with the iliac-only group.

Conclusion

For concomitant iliac and superficial femoral artery occlusive disease, iliac-only revascularization has favorable efficacy and safety outcomes compared with complete multi-level revascularization in selected patients with patent profunda femoris artery and at least one healthy outflow tract of the infrapopliteal artery.

Midterm Results of Drug-Coated Balloon Alone or Combined with Rotarex Thrombectomy Device for Treatment of Subacute Femoropopliteal Artery Thrombotic Occlusion

BACKGROUND

This retrospective multicenter study aimed to compare the midterm results of the Rotarex rotational thrombectomy device combined with drug-coated balloon (DCB) and DCB-alone for the treatment of subacute femoropopliteal artery thrombotic occlusion.

METHODS

All patients (74, aged 70.1 ± 9.3 years) were nonrandomized and divided into 2 groups based on treatment strategy between 2018 and 2020. Intraoperative technical success (defined as <30% residual stenosis), dissection types and bailout-stenting rates were assessed. Ankle-brachial index (ABI), primary patency (PP, restenosis <50%) and freedom from clinically driven target lesion reintervention (CD-TLR) were documented at follow-up.

RESULTS

Among them, 35 patients were treated with the Rotarex catheter combined with DCB while 39 patients underwent DCB-alone. The-overall technical success rate was 100%. Patients in the Rotarex + DCB group showed lower rate of bailout stenting than those in the DCB alone group (22.9% vs. 59.0%; P = 0.01). ABI at discharge was significantly higher in both groups. Mean follow-up time was 18.5 ± 3.4 months; 62 patients completed Doppler ultrasound investigation while 12 patients were censored. According to Kaplan-Meier analysis, the estimated PP was 82.0 ± 6.7% in the Rotarex + DCB group, whereas a significantly lower rate in the DCB alone group (60.9 ± 8.3%, P = 0.04). In addition, the freedom from CD-TLR rate was 82.9 ± 6.4% in the Rotarex + DCB group and 61.5 ± 7.8% in the DCB-alone group (P = 0.04).

CONCLUSIONS

These initial data indicate that the Rotarex thrombectomy device combined with DCB is an effective choice for the treatment of subacute femoropopliteal artery thrombotic occlusion compared to DCB-alone. The combined procedure had superior midterm results.

Collateral Arteriogenesis Involves a Sympathetic Denervation That Is Associated With Abnormal α-Adrenergic Signaling and a Transient Loss of Vascular Tone

Stimulating collateral arteriogenesis is an attractive therapeutic target for peripheral artery disease (PAD). However, the potency of arteriogenesis-stimulation in animal models has not been matched with efficacy in clinical trials. This may be because the presence of enlarged collaterals is not sufficient to relieve symptoms of PAD, suggesting that collateral function is also important. Specifically, collaterals are the primary site of vascular resistance following arterial occlusion, and impaired collateral vasodilation could impact downstream tissue perfusion and limb function. Therefore, we evaluated the effects of arteriogenesis on collateral vascular reactivity. Following femoral artery ligation in the mouse hindlimb, collateral functional vasodilation was impaired at day 7 (17 ± 3 vs. 60 ± 8%) but restored by day 28. This impairment was due to a high resting diameter (73 ± 4 μm at rest vs. 84 ± 3 μm dilated), which does not appear to be a beneficial effect of arteriogenesis because increasing tissue metabolic demand through voluntary exercise decreased resting diameter and restored vascular reactivity at day 7. The high diameter in sedentary animals was not due to sustained NO-dependent vasodilation or defective myogenic constriction, as there were no differences between the enlarged and native collaterals in response to eNOS inhibition with L-NAME or L-type calcium channel inhibition with nifedipine, respectively. Surprisingly, in the context of reduced vascular tone, vasoconstriction in response to the α-adrenergic agonist norepinephrine was enhanced in the enlarged collateral (−62 ± 2 vs. −37 ± 2%) while vasodilation in response to the α-adrenergic antagonist prazosin was reduced (6 ± 4% vs. 22 ± 16%), indicating a lack of α-adrenergic receptor activation by endogenous norepinephrine and suggesting a denervation of the neuroeffector junction. Staining for tyrosine hydroxylase demonstrated sympathetic denervation, with neurons occupying less area and located further from the enlarged collateral at day 7. Inversely, MMP2 presence surrounding the enlarged collateral was greater at day 7, suggesting that denervation may be related to extracellular matrix degradation during arteriogenesis. Further investigation on vascular wall maturation and the functionality of enlarged collaterals holds promise for identifying novel therapeutic targets to enhance arteriogenesis in patients with PAD.

With a Little Help From My Friends: the Role of the Renal Collateral Circulation in Atherosclerotic Renovascular Disease

The collateral circulation can adapt to bypass major arteries with limited flow and serves a crucial protective role in coronary, cerebral, and peripheral arterial disease. Emerging evidence indicates that the renal collateral circulation can similarly adapt and thereby limit kidney ischemia in atherosclerotic renovascular disease. These adaptations predominantly include recruitment of preexisting microvessels for arteriogenesis, with de novo vessel formation playing a limited role. Yet, adaptations of the renal collateral circulation in renovascular disease are often insufficient to fully compensate for the limited flow within an obstructed renal artery and may be hampered by the severity of obstruction or patient comorbidities. Experimental strategies have attempted to circumvent limitations of collateral formation and improve the prognosis of patients with various ischemic vascular territories. These have included pharmacological approaches such as endothelial growth factors, renin-angiotensin-aldosterone system blockade, and If-channel-blockers, as well as interventions like preconditioning, exercise, enhanced external counter-pulsation, and low-energy shock-wave therapy. However, few of these strategies have been implemented in atherosclerotic renovascular disease. This review summarizes current understanding regarding the development of renal collateral circulation in atherosclerotic renovascular disease. Studies are needed to apply lessons learned in other vascular beds in the setting of atherosclerotic renovascular disease to develop new treatment regimens for this patient group.

Accuracy of Acceleration Time of Distal Arteries to Diagnose Severe Peripheral Arterial Disease

Context

Ankle-brachial index (ABI) and toe-brachial index (TBI) are the recommended tests for the diagnosis of lower extremity peripheral artery disease (PAD) and the assessment of its severity, whereas Doppler ultrasound (DUS) is usually used to localize vascular lesions. However, the performance of DUS as an alternative to TBI and ABI measurement is unknown.

Objective

The goals were (i) to evaluate the correlation between DUS parameters of distal arteries of the lower extremities with TBI in patients with PAD; (ii) to evaluate the correlation between DUS parameters of distal arteries with ABI; and (iii) to assess the diagnostic accuracy of maximal acceleration time of pedal arteries to detect toe pressure ≤30 mmHg.

Methods

An observational retrospective study was conducted for 1 year on patients with the diagnosis of PAD on DUS. Demographic data, ABI, TBI, and DUS parameters of the dorsal pedis and lateral plantar arteries (DPA and LPA) were recorded.

Results

Seventy-seven patients with 88 limbs were included, aged 69 [interquartile range: 11 years] with 28.6% of diabetic patients. The highest acceleration time of either DPA or LPA (ATmax) was the most correlated to TBI on both univariate (r = −0.78, p &lt; 0.0001) and multivariate analysis (p &lt; 0.0001). DUS parameters had a weaker correlation with ABI. ATmax &gt; 215 ms showed high diagnosis accuracy to a toe pressure of 30 mmHg or less [sensitivity of 86% [0.57–0.98] and negative predictive value of 97% [0.89–1.00]].

Conclusion

ATmax demonstrates a high correlation with TBI in patients with PAD, and high diagnostic accuracy for detection of critical limb ischemia. Based on these results, ATmax can represent the next step in evaluating PAD severity with DUS, in patients with advanced lower extremity PAD.

Satellite Cell Expression of RAGE (Receptor for Advanced Glycation end Products) Is Important for Collateral Vessel Formation

Background The growth and remodeling of vascular networks is an important component of the prognosis for patients with peripheral artery disease. One protein that has been previously implicated to play a role in this process is RAGE (receptor for advanced glycation end products). This study sought to determine the cellular source of RAGE in the ischemic hind limb and the role of RAGE signaling in this cell type. Methods and Results Using a hind limb ischemia model of vascular growth, this study found skeletal muscle satellite cells to be a novel major cellular source of RAGE in ischemic tissue by both staining and cellular sorting. Although wild-type satellite cells increased tumor necrosis factor-α and monocyte chemoattractant protein-1 production in response to ischemia in vivo and a RAGE ligand in vitro, satellite cells from RAGE knockout mice lacked the increase in cytokine production both in vivo in response to ischemia and in vitro after stimuli with the RAGE ligand high-mobility group box 1. Furthermore, encapsulated wild-type satellite cells improved perfusion after hind limb ischemia surgery by both perfusion staining and vessel quantification, but RAGE knockout satellite cells provided no improvement over empty capsules. Conclusions Thus, RAGE expression and signaling in satellite cells is crucial for their response to stimuli and angiogenic and arteriogenic functions.

Avoiding revascularization strategy versus revascularization with drug-coated balloon for the treatment of superficial femoral artery occlusive disease

OBJECTIVE

The aim of this study was to compare the efficacy, safety and treatment costs of superficial femoral artery revascularization (SFA) with drug-coated balloon(DCB) versus avoiding revascularization strategy for the treatment of symptomatic SFA disease.

METHODS

This retrospective single-center study reviewed 96 patients (113 limbs) with severe stenosis and occlusive SFA disease. All patients underwent either DCB(Group 1: n ​= ​55 limbs) or nonrevascularization (Group 2: n ​= ​58 limbs) between March 2015 and June 2019. The improvement of Rutherford class, walking impairment questionnaire score(WIQ), target limb reintervention, perioperative major adverse events, the catheterization laboratory cost and length of hospital stay were compared. The limb salvage and survival rates were calculated using the Kaplan-Meier method. Univariate and multivariate logistic regression analysis were performed to assess the association between factors and the improvement of Rutherford category at 12 months.

RESULTS

The median follow-up time of Groups 1 and 2 was 17 and 33 months, respectively. At 12 months, the Rutherford category significantly decreased in both groups (P ​< ​0.001), with no significant difference (79.7% vs. 64.3%, P ​= ​0.074). Furthermore, multivariate analysis showed that the selected therapeutic method was not an influential factor for the improvement of Rutherford class at 12 months. The WIQ overall score as well as three subscales scores (distance, speed and stair-climbing), the survival rate, limb salvage rate and the length of stay between the two groups were comparable. The perioperative adverse events rate and catheterization laboratory cost in Group 2 was significantly lower compared to Group 1 [(34253.69 ​± ​28172.87) yuan vs. (56936.76 ​± ​41278.36) yuan, P ​= ​0.001].

CONCLUSIONS

This study suggests that avoiding superficial femoral artery revascularization strategy has favorable efficacy and safety outcomes compared to combining revascularization with DCB in selected patients.

Remodeling of occluded internal carotid artery in vessel wall magnetic resonance imaging

OBJECTIVE

The purpose of the present study was to investigate the remodeling pattern of the extracranial occluded internal carotid artery (OICA) by vessel wall magnetic resonance imaging (VWI).

METHODS

Thirty-nine atherosclerotic OICAs from 32 consecutive cases underwent 3-Tesla VWI to acquire pre- and post-contrast T1-weighted two-dimensional fluid-attenuated inversion recovery fast spin echo sequences. 25 symptomatic CAs exhibited ipsilateral downstream cerebral ischemia or ophthalmic artery embolism within last three months. The 14 remaining CAs were asymptomatic. Twenty-four CAs from 22 patients with atherosclerosis but no stenosis were recruited as control group. The outer wall area (OWA) was calculated based on the outer contour of the carotid artery drawn on the pre-contrast VWI. Negative remodeling was defined as a lower OWA compared to that of control group.

RESULTS

Clinical characteristics including age, sex and vascular risk factors showed no significant difference between the occluded and control group. However, the OWA was lower in the occluded group than in the control group (0.63 versus 0.90 cm², p = 0.004). For all OICAs, the OWA was larger in symptomatic cases than asymptomatic cases (0.71 versus 0.49cm², p = 0.025). Using a cutoff value of 0.44, the sensitivity and specificity of OWA for detecting symptomatic OICA were 0.88 and 0.57, respectively. Heterogeneous signal intensity and enhancement were more often observed at the proximal than the distal segment of occlusion (p < 0.001). The inter-observer agreement regarding the evaluation of VWI characteristics was desirable (κ = 0.805 ∼ 0.847).

CONCLUSIONS

Negative remodeling is prevalent in OICA, especially in asymptomatic cases.

VEGF receptor targeted imaging of angiogenic response to limb ischemia in diabetic vs. non-diabetic Yucatan minipigs

Background

New therapies to treat diabetic peripheral artery disease (PAD) require target-specific non-invasive imaging modalities to follow efficacy. As a translational study, we performed targeted imaging of receptors for vascular endothelial growth factor (VEGF) in response to anterior femoral artery occlusion (FAO) in Yucatan minipigs and compare the normal response to response in diabetic Yucatan minipigs.

Methods

Eleven Yucatan minipigs, 6 non-diabetic (non-D) and 5 purpose bred diabetic (D) (Sinclair, Auxvasse MO), underwent intravascular total occlusion of the anterior femoral artery (FA). At days 1 and 28, pigs underwent SPECT/CT ²⁰¹Tl hindlimb perfusion imaging and at day 7 were injected with [^99mTc]DOTA-PEG-scVEGF (scV/Tc) tracer targeting VEGF receptor, and underwent biopsies of the hindlimb muscles for gamma counting and histology, followed by imaging. One day after the final scan, pigs underwent contrast angiography of the lower extremities. Counts from scans were converted to percentage injected activity (%IA).

Results

Perfusion was lower in the occluded hindlimb compared to non-occluded on day 1 in both the D and non-D pigs. At day 7, scV/Tc count ratio of counts from ROIs drawn in proximal gastrocnemius muscle for the occluded over non-occluded limb was significantly higher in non-D vs. D pigs (1.32 ± 0.06 vs. 1.04 ± 0.13, P = 0.02) reflecting higher level of angiogenesis. Perfusion increased between days 1 and 28 in the muscles in the occluded limb for the non-diabetic pigs while the diabetic pig showed no increase (+ 0.13 ± 0.08 %IA vs. − 0.13 ± 0.11, P = 0.003). The anterior FA showed poor contrast filling beyond occluder and qualitatively fewer bridging collaterals compared to non-D pigs at 28 days.

Conclusion

VEGF receptor targeted imaging showed the effects of diabetes to suppress angiogenesis in response to occlusion of the anterior femoral artery of purpose bred diabetic Yucatan minipigs and indicates potential applicability as a marker to follow efficacy of novel therapies to improve blood flow by stimulating angiogenesis in diabetic PAD.

Thrombospondin-4 increases with the severity of peripheral arterial disease and is associated with diabetes

Thrombospondin-4 (TSP-4) is an extracellular matrix protein of the vessel wall. Despite bench evidence, its significance in the clinical setting of atherosclerosis is missing. TSP-4 (ng/ml) was measured in 365 PAD patientsusing a commercially available ELISA. PAD was diagnosed by the ankle–brachial index (ABI) and clinically graded using the Fontaine classification. TSP-4 levels were significantly higher in Fontaine II vs. Fontaine I (4.78 ± 0. 42, 4.69 ± 0.42, p = 0.043). TSP-4 significantly correlated with ABI (r = − 0.141, p = 0.023, n = 259) after the exclusion of mediasclerotic patients. Binary logistic regression analysis for Fontaine I vs. II showed an OR of 1.70 (1.02–2.82) in a multivariable model adjusted for traditional risk factors. Interestingly, TSP-4 levels were higher in patients with type 2 diabetes mellitus or prediabetes (DGT) compared with normal glucose tolerance (NGT) (4.76 ± 0.42 vs. 4.66 ± 0.41, p = 0.035). ANOVA for PAD and diabetes subgroups showed a linear increase with disease burden with the highest difference between Fontaine I-NGT and Fontaine II-DGT (4.59 ± 0.40, 4.79 ± 0.43, p = 0.015). TSP-4 levels increased with PAD severity and showed a former unknown association with diabetes. Thus, TSP-4 could be a novel marker of atherosclerotic activity, especially in the major subgroup of patients with concomitant diabetes.

Association of gait speed and grip strength with risk of cardiovascular events in patients on haemodialysis: a prospective study

Background

Gait speed (GS) and handgrip strength (HGS), both factors associated with frailty and sarcopenia, are reportedly associated with CV events in the general population. However, little is known about the impact of these factors on the outcome of patients on dialysis. This study aimed to evaluate whether evaluation of GS and HGS could be associated the onset of fatal/non-fatal cardiovascular (CV) events in patients on haemodialysis (HD).

Methods

One-hundred-eighty-two patients with end-stage renal disease (ESRD) undergoing HD at four dialysis clinics in April 2015 provided written informed consent to participate in the study. We excluded patients who had physical disability, were unable to walk without help, or had recently experienced CV events. Usual GS over a 4-m walk and HGS were measured at baseline, and 173 patients (men, 124; women, 49) were divided into sex-specific quartiles according to GS and HGS and were followed-up for fatal/non-fatal CV events for a median of 2 years. We examined the association of GS and HGS with CV events and determined cut-off values using Cox regression analysis adjusted for age, sex, HD duration, history of CVD, and diabetes.

Results

During the follow-up period, 46 CV events occurred. Both physical performance factors were significantly associated with CV events. Low GS (< 0.82 m/s for men and 0.81 m/s for women) and weak HGS (< 29.0 kg for men and 19.7 kg for women) were associated with CV events. For low vs. high GS, the hazard ratio (HR) for CV events was 2.29 [95% confidence interval (CI): 1.20–4.33; P = 0.01], and for low vs. high HGS, the HR was 2.15 [95% CI: 1.00–5.04; P < 0.05]. These HRs remained significant after adjusting for confounding factors, such as sex, age, dialysis vintage, history of CV disease, and diabetes.

Conclusions

Slow GS and weak HGS in patients on HD were suggested to be independent predictors of fatal/non-fatal CV events.

Electronic supplementary material

The online version of this article (10.1186/s12882-019-1370-6) contains supplementary material, which is available to authorized users.

Recent advances in magnetic resonance imaging for peripheral artery disease

The global burden of peripheral artery disease (PAD) is significant. This has led to numerous recent advances in magnetic resonance imaging (MRI) techniques in PAD. Older techniques such as time of flight MRI or phase contrast MRI are burdened by long acquisition times and significant issues with artifacts. In addition, the most used MRI modality, contrast-enhanced MR angiography (CE-MRA) is limited by the use of gadolinium contrast and its potential toxicity. Novel MRI techniques such as arterial spin labeling (ASL), blood-oxygen-level dependent imaging (BOLD), and first-pass perfusion gadolinium enhancement are advancing the field by providing skeletal muscle perfusion/oxygenation data while maintaining excellent spatial and temporal resolution. Perfusion data can be critical to providing objective clinical data of a visualized stenosis. In addition, there are a number of new MRI sequences assessing plaque composition and lesion severity in the absence of contrast. These approaches used in combination can provide useful clinical and prognostic data and provide critical endpoints in PAD research.

Discrepancies in Prevalence of Peripheral Arterial Disease between Lower Extremities at Rest and Postexercise

Background  Lower extremity peripheral arterial disease (PAD) is a common medical condition causing substantial morbidity. Limited data exist on whether discrepancies in PAD prevalence exist between the lower extremities using resting ankle-brachial indices (ABIs) and postexercise pressures. Objective  We predicted the prevalence of PAD between the lower extremities. Methods and Results  Consecutive patients who had undergone a noninvasive arterial lower extremity study at Mayo Clinic, Rochester, MN, between January 1996 and December 2012 with suspected PAD were retrospectively reviewed. We identified 12,312 consecutive patients who underwent an arterial lower extremity and an exercise treadmill study. Prevalence of PAD was assessed at rest and after exercise using two criteria: a resting ABI ≤ 0.90 and a postexercise pressure decrease of > 30 mm Hg. Mean age was 67 ± 12 years and there were 4,780 (39%) women studied. At rest, we found a higher prevalence of PAD on the left extremity (27.4%) compared with the right (24.6%) ( p  < 0.0001). After exercise, we found a higher prevalence of PAD on the right extremity (25.1%) compared with the left (19.0%) ( p  < 0.0001). These discrepancies between the prevalence of PAD at rest and after exercise were present in women and men. Conclusion  Using validated criteria of a resting ABI of ≤ 0.90 and postexercise ankle pressure decrease > 30 mm Hg, our results suggest that there is a significantly higher prevalence of PAD in the left lower extremity at rest, in contrast to a greater prevalence of abnormal postexercise testing in the right lower extremity. The reason(s) of these discrepancies remain to be studied.

Femoral Artery Atherosclerosis Is Associated With Physical Function Across the Spectrum of the Ankle-Brachial Index: The San Diego Population Study

Background

The ankle‐brachial index (ABI) is inadequate to detect early‐stage atherosclerotic disease, when interventions to prevent functional decline may be the most effective. We determined associations of femoral artery atherosclerosis with physical functioning, across the spectrum of the ABI, and within the normal ABI range.

Methods and Results

In 2007–2011, 1103 multiethnic men and women participated in the San Diego Population Study, and completed all components of the summary performance score. Using Doppler ultrasound, superficial and common femoral intima media thickness and plaques were ascertained. Logistic regression was used to assess associations of femoral atherosclerosis with the summary performance score and its individual components. Models were adjusted for demographics, lifestyle factors, comorbidities, lipids, and kidney function. In adjusted models, among participants with a normal‐range ABI (1.00–1.30), the highest tertile of superficial intima media thickness was associated with lower odds of a perfect summary performance score of 12 (odds ratio=0.56 [0.36, 0.87], P=0.009), and lower odds of a 4‐m walk score of 4 (0.34 [0.16, 0.73], P=0.006) and chair rise score of 4 (0.56 [0.34, 0.94], P=0.03). Plaque presence (0.53 [0.29, 0.99], P=0.04) and greater total plaque burden (0.61 [0.43, 0.87], P=0.006) were associated with worse 4‐m walk performance in the normal‐range ABI group. Higher superficial intima media thickness was associated with lower summary performance score in all individuals (P=0.02).

Conclusions

Findings suggest that use of femoral artery atherosclerosis measures may be effective in individuals with a normal‐range ABI, especially, for example, those with diabetes mellitus or a family history of peripheral artery disease, when detection can lead to earlier intervention to prevent functional declines and improve quality of life.

Racial differences in functional decline in peripheral artery disease and associations with socioeconomic status and education

OBJECTIVE

The objective of this study was to determine whether blacks with lower extremity peripheral artery disease (PAD) have faster functional decline than whites with PAD.

METHODS

Participants with ankle-brachial index <0.90 were identified from Chicago medical centers and observed longitudinally. Mobility impairment and the 6-minute walk were assessed at baseline and every 6 to 12 months. Mobility loss was defined as becoming unable to walk up and down a flight of stairs or to walk ¼ mile without assistance.

RESULTS

Of 1162 PAD participants, 305 (26%) were black. Median follow-up was 46.0 months. Among 711 PAD participants who walked 6 minutes continuously at baseline, black participants were more likely to become unable to walk 6 minutes continuously during follow-up (64/171 [37.4%] vs 156/540 [28.9%]; log-rank, P = .006). Black race was associated with becoming unable to walk 6 minutes continuously, adjusting for age, sex, ankle-brachial index, comorbidities, and other confounders (hazard ratio, 1.45; 95% confidence interval, 1.05-1.99; P = .022). This association was attenuated after adjustment for income and education (P = .229). Among 844 participants without baseline mobility impairment, black participants had a higher rate of mobility loss (64/209 [30.6%] vs 164/635 [25.8%]; log-rank, P = .009). Black race was associated with increased mobility loss, adjusting for potential confounders (hazard ratio, 1.42; 95% confidence interval, 1.04-1.94; P = .028). This association was attenuated after additional adjustment for income and education (P = .392) and physical activity (P = .113). There were no racial differences in average annual declines in 6-minute walk, usual-paced 4-meter walking velocity, or fast-paced 4-meter walking velocity.

CONCLUSIONS

Black PAD patients have higher rates of mobility loss and becoming unable to walk for 6 minutes continuously. These differences appear related to racial differences in socioeconomic status and physical activity.

Community walking speed, sedentary or lying down time, and mortality in peripheral artery disease

We studied whether slower community walking speed and whether greater time spent lying down or sleeping were associated with higher mortality in people with lower extremity peripheral artery disease (PAD). Participants with an ankle-brachial index (ABI) < 0.90 were identified from Chicago medical centers. At baseline, participants reported their usual walking speed outside their home and the number of hours they spent lying down or sleeping per day. Cause of death was adjudicated using death certificates and medical record review. Analyses were adjusted for age, sex, race, comorbidities, ABI, and other confounders. Of 1314 PAD participants, 189 (14.4%) died, including 63 cardiovascular disease (CVD) deaths. Mean follow-up was 34.9 months ± 18.1. Relative to average or normal pace (2-3 miles/hour), slower walking speed was associated with greater CVD mortality: no walking at all: hazard ratio (HR) = 4.17, 95% confidence interval (CI) = 1.46-11.89; casual strolling (0-2 miles/hour): HR = 2.24, 95% CI = 1.16-4.32; brisk or striding (>3 miles/hour): HR = 0.55, 95% CI = 0.07-4.30. These associations were not significant after additional adjustment for the six-minute walk. Relative to sleeping or lying down for 8-9 hours, fewer or greater hours sleeping or lying down were associated with higher CVD mortality: 4-7 hours: HR = 2.08, 95% CI = 1.06-4.05; 10-11 hours: HR = 4.07, 95% CI = 1.86-8.89; ⩾ 12 hours: HR = 3.75, 95% CI = 1.47-9.62. These associations were maintained after adjustment for the six-minute walk. In conclusion, slower walking speed outside the home and less than 8 hours or more than 9 hours lying down per day are potentially modifiable behaviors associated with increased CVD mortality in patients with PAD.

Incidence and Prognostic Significance of Depressive Symptoms in Peripheral Artery Disease

Background

We compared the incidence of depression, defined by a Geriatric Depression Score (GDS) ≥6, between people with versus without peripheral artery disease (PAD). We determined whether depressive symptoms were associated with increased mortality in people with and without PAD.

Methods and Results

Nine hundred and fifty‐one PAD patients and 478 non‐PAD patients were recruited from Chicago medical centers and followed prospectively. At baseline and annually, participants completed the GDS (0–15 scale, score ≥6=depression) and 6‐minute walk. Cause of death was confirmed with death certificates. The prevalence of a GDS ≥6 at baseline was 186/951 (19.6%) among PAD versus 63/478 (13.2%) among non‐PAD participants (P=0.003). During a mean follow‐up of 2.7±1.2 years, 122/712 (17.1%) of participants with PAD versus 51/403 (12.7%) without PAD developed a GDS ≥6 (P=0.047). Adjusting for age, sex, race, comorbidities, and other confounders, PAD participants had an increased rate of developing a GDS ≥6 compared to non‐PAD participants (hazard ratio=1.54 (95% CI=1.05–2.25, P=0.026). This association was not statistically significant after adjusting for 6‐minute walk (P=0.258). Among PAD participants, a baseline GDS ≥6 was associated with increased all‐cause mortality, adjusting for confounders (hazard ratio=1.57, 95% CI=1.12–2.21, P=0.009). This association was not significant after adjusting for 6‐minute walk (P=0.224).

Conclusions

People with PAD have a higher incidence of depressive symptoms than people without PAD. In PAD, depressive symptoms are associated with increased all‐cause and cardiovascular mortality. These associations are explained in part by poorer 6‐minute walk among people with PAD and among depressed people with PAD, respectively.

Physical exercise and quantitative lower limb collateral function

Objective

This study tested the hypothesis that global physical activity and physical performance parameters are directly related to invasively obtained left superficial femoral artery (SFA) collateral flow index (CFI).

Background

So far, the association between different measures of physical exercise activity and quantitative lower limb collateral function has not been investigated.

Methods

The primary study end point was pressure-derived CFI as obtained during a 3 min left SFA balloon occlusion. CFI is the ratio of simultaneously recorded mean SFA distal occlusive pressure divided by mean aortic pressure, both subtracted by central venous pressure. As independent variables, the items of the Global Physical Activity Questionnaire (GPAQ) and physical exercise performance (maximal workload in watts) as achieved during a bicycle or treadmill exercise test were determined. The secondary study end point was transcutaneous left calf partial oxygen pressure (PO₂ in mm Hg) divided by transcutaneous PO₂ at a non-ischaemic reference site as obtained simultaneously to CFI measurement.

Results

Of the 110 study patients undergoing diagnostic coronary angiography, 79 belonged to the group without and 31 with engagement in regular intensive leisure time physical activity according to GPAQ. Left SFA CFI tended to be lower in the group without than with intensive leisure time physical activity: 0.514 ±0.141 vs 0.560 ±0.184 (p =0.0566). Transcutaneous PO₂ index was associated with simultaneous left SFA CFI: CFI =018 +0.57 PO₂ index; p<0.0001. Maximal physical workload was directly associated with left SFA CFI: CFI =0.40 +0.0009 maximal workload; p =0.0044.

Conclusions

Quantitative left SFA collateral function is directly reflected by maximal physical workload as achieved during an exercise test.

Trial registration number

NCTO02063347.

Comparing Supervised Exercise Therapy to Invasive Measures in the Management of Symptomatic Peripheral Arterial Disease

Peripheral arterial disease (PAD) is associated with considerable morbidity and mortality. Consensus rightly demands the incorporation of supervised exercise training (SET) into PAD treatment protocols. However, the exact role of SET particularly its relationship with intervention requires further clarification. While supervised exercise is undoubtedly an excellent tool in the conservative management of mild PAD its use in more advanced disease as an adjunct to open or endovascular intervention is not clearly defined. Indeed its use in isolation in this cohort is incompletely reported. The aim of this review is to clarify the exact role of SET in the management of symptomatic PAD and in particular to assess its role in comparison with or as an adjunct to invasive intervention. A systematic literature search revealed a total 11 randomised studies inclusive of 969 patients. All studies compared SET and intervention with monotherapy. Study results suggest that exercise is a complication-free treatment. Furthermore, it appears to offer significant improvements in patients walk distances with a combination of both SET and intervention offering a superior walking outcome to monotherapy in those requiring invasive measures.

Computation of blood flow through collateral circulation of the superficial femoral artery

OBJECTIVE

Obliteration of collaterals during (endo)vascular treatment of peripheral arterial occlusive disease is considered detrimental. We use a model to calculate maximum collateral bed flow of the superficial femoral artery in order to provide insight in their hemodynamic relevance.

METHOD

A computational model was developed using digital subtraction angiographies in combination with Poiseuille's equation and Ohm's law. Lesions were divided into short and long (<15 cm and ≥15 cm, respectively) and into stenosis and occlusions. Data are presented in relation to the calculated maximum healthy superficial femoral artery flow.

RESULTS

Stenotic lesions are longer than occlusive lesions (P < 0.05) and occlusions had more and larger collaterals (P < 0.05). In all four study groups the collateral flow significantly increased the total flow (P < 0.05). The maximum collateral system flow in the stenosis and occlusion groups was 5.1% and 20.8% of healthy superficial femoral artery flow, respectively (P < 0.05), and there were no significant differences between short and long lesions (11.2% and 6.7% of healthy superficial femoral artery flow, respectively).

CONCLUSION

The maximum collateral system flow of the superficial femoral artery is only a fraction, with a maximum of one fifth, of healthy superficial femoral artery flow. Effects of collateral vessel occlusion during (endo)vascular treatment may therefore be without detrimental consequences.

The factors affecting recurrence of symptoms after infrainguinal arterial endovascular angioplasty

Background

This study reports the result of endovascular treatment for arterial occlusive disease limited to femoropopliteal lesions, focusing on the recurrence of symptoms instead of patency.

Methods

This was a retrospective, single-center study. From April 2007 to November 2011, 48 limbs in 38 patients underwent endovascular stenting or balloon angioplasty to treat femoropopliteal arterial occlusive disease. The factors affecting the recurrence of symptoms were analyzed.

Results

The mean age of the patients was 69.60±7.62 years. Among the baseline characteristics of the patients, initial hyperlipidemia was the most important factor affecting the recurrence of symptoms (relative risk=5.810, p=0.031). The presence of a dorsal arch was also a significant factor (relative risk=0.675, p=0.047).

Conclusion

The major factors that affect the recurrence of symptoms after endovascular treatment for femoropopliteal arterial occlusive lesions are hyperlipidemia and the presence of a dorsal arch. Therefore, the usage of lipid-lowering agents after endovascular treatment and taking the presence of a dorsal arch into consideration are important elements of managing the recurrence of symptoms.

High-risk plaque in the superficial femoral artery of people with peripheral artery disease: prevalence and associated clinical characteristics

OBJECTIVE

We used magnetic resonance imaging (MRI) to study the prevalence and associated clinical characteristics of high-risk plaque (defined as presence of lipid-rich necrotic core [LRNC] and intraplaque hemorrhage) in the superficial femoral arteries (SFA) among people with peripheral artery disease (PAD).

BACKGROUND

The prevalence and clinical characteristics associated with high-risk plaque in the SFA are unknown.

METHODS

Three-hundred-three participants with PAD underwent MRI of the proximal SFA using a 1.5 T S platform. Twelve contiguous 2.5 mm cross-sectional images were obtained.

RESULTS

LRNC was present in 68 (22.4%) participants. Only one had intra-plaque hemorrhage. After adjusting for age and sex, smoking prevalence was higher among adults with LRNC than among those without LRNC (35.9% vs. 21.4%, p = 0.02). Among participants with vs. without LRNC there were no differences in mean percent lumen area (31% vs. 33%, p = 0.42), normalized mean wall area (0.71 vs. 0.70, p = 0.67) or maximum wall area (0.96 vs. 0.92, p = 0.54) in the SFA. Among participants with LRNC, cross-sectional images containing LRNC had a smaller percent lumen area (33% ± 1% vs. 39% ± 1%, p < 0.001), greater normalized mean wall thickness (0.25 ± 0.01 vs. 0.22 ± 0.01, p < 0.001), and greater normalized maximum wall thickness (0.41 ± 0.01 vs. 0.31 ± 0.01, p < 0.001), compared to cross-sectional images without LRNC.

CONCLUSIONS

Fewer than 25% of adults with PAD had high-risk plaque in the proximal SFA using MRI. Smoking was the only clinical characteristic associated with presence of LRNC. Further study is needed to determine the prognostic significance of LRNC in the SFA.

CLINICAL TRIAL REGISTRATION-URL

http://www.clinicaltrials.gov. Unique identifier: NCT00520312.

Serum endostatin concentrations are higher in men with symptoms of intermittent claudication

Objectives. A cleavage fragment of collagen XVIII, endostatin, is released into the circulation and has been demonstrated to have antiangiogenic effects in animal models. We hypothesized that circulating endostatin would be increased in patients with symptoms of lower limb peripheral artery disease. Design. Cross-sectional study. Participants. Community dwelling older men. Measurements. Intermittent claudication was defined using the Edinburgh Claudication Questionnaire (ECQ). Serum endostatin was measured by a commercial ELISA. The association of serum endostatin with intermittent claudication was examined using logistic regression adjusting for age, diabetes, hypertension, dyslipidemia, coronary heart disease, and stroke. Results. Serum endostatin was measured in 1114 men who completed the ECQ. 106 men had intermittent claudication, 291 had atypical pain, and 717 had no lower limb pain. Mean (±standard deviation) serum endostatin concentrations (ng/mL) were 145.22 ± 106.93 for men with intermittent claudication, 129.11 ± 79.80 for men with atypical pain, and 116.34 ± 66.57 for men with no lower limb pain; P < 0.001. A 70 ng/mL increase in endostatin was associated with a 1.17-fold rise in the adjusted odds of having intermittent claudication (OR 1.17, 95% confidence interval 1.00–1.37, and P = 0.050). Conclusions. Serum endostatin is raised in older men who have symptoms of intermittent claudication. The role of endostatin in the genesis and outcome of peripheral artery disease requires further investigation.

Functional impairment in peripheral artery disease and how to improve it in 2013

Lower extremity peripheral artery disease (PAD) affects 8 million men and women in the United States and will be increasingly common as the U.S. population lives longer with chronic disease. People with PAD have poorer walking endurance, slower walking velocity, and poorer balance, compared with individuals without PAD. People with PAD may reduce their walking activity to avoid leg symptoms. Thus, clinicians should not equate stabilization or improvement in exertional leg symptoms with stabilization or improvement in walking performance in PAD. In addition, even asymptomatic PAD patients have greater functional impairment and faster functional decline than individuals without PAD. Of the 2 FDA-approved medications for treating claudication symptoms, pentoxifylline may not be more efficacious than placebo, whereas cilostazol confers a modest improvement in treadmill walking performance. Supervised treadmill walking exercise is associated with substantial improvement in walking endurance, but many PAD patients do not have access to supervised exercise programs. Unsupervised walking exercise programs may be beneficial in PAD, but data are mixed.