Relation of Baseline Renal Dysfunction With Outcomes in Patients Undergoing Popliteal and Infrapopliteal Percutaneous Peripheral Arterial Interventions

Peripheral Arterial Diseases and Diabetes Mellitus: Associations With Quality of Health Measures in Patients Undergoing Percutaneous Vascular Interventions

BACKGROUND

Peripheral arterial disease (PAD) is more prevalent and severe in patients with diabetes mellitus (DM) compared with those without DM. Peripheral vascular intervention (PVI) is often used in patients failing conservative management. The association of PVI with health status in diabetic patients has yet to be determined.

METHODS

We analyzed the clinical response to PVI in DM (n = 203, 52 %) compared with non-DM patients (n = 183, 48 %), using the Peripheral Arterial Questionnaire (PAQ) for patients during baseline and a maximum 6 months after PVI. We used the PAQ summary score, which summarized the patients' level of physical and social function, patient symptoms, and overall quality of life. This represented the PAD-related Quality of Health (QOH). Our score range is between 0 (lowest health quality) and 100 (highest health quality).

RESULTS

Compared with non-DM patients, those with DM were more likely to have a history of prior PVI, an increased prevalence of PAD risk factors, and significantly lower QOH scores at baseline (32.7 ± 20 vs 37.5 ± 20.6, p = 0.02). After adjustment for baseline confounding, neither the baseline, the change, nor the final summary scores were significantly different between groups, suggesting similar symptomatic and functional improvement in non-DM and DM patients post-PVI.

CONCLUSIONS

Following PVI, PAD-specific health status showed a similar improvement in patients with and without DM, illustrating that use of this strategy among patients with multiple comorbidities or diffuse PAD as useful.

Skeletal Muscle Mitochondrial Dysfunction and Oxidative Stress in Peripheral Arterial Disease: A Unifying Mechanism and Therapeutic Target

Peripheral artery disease (PAD) is caused by atherosclerosis in the lower extremities, which leads to a spectrum of life-altering symptomatology, including claudication, ischemic rest pain, and gangrene requiring limb amputation. Current treatments for PAD are focused primarily on re-establishing blood flow to the ischemic tissue, implying that blood flow is the decisive factor that determines whether or not the tissue survives. Unfortunately, failure rates of endovascular and revascularization procedures remain unacceptably high and numerous cell- and gene-based vascular therapies have failed to demonstrate efficacy in clinical trials. The low success of vascular-focused therapies implies that non-vascular tissues, such as skeletal muscle and oxidative stress, may substantially contribute to PAD pathobiology. Clues toward the importance of skeletal muscle in PAD pathobiology stem from clinical observations that muscle function is a strong predictor of mortality. Mitochondrial impairments in muscle have been documented in PAD patients, although its potential role in clinical pathology is incompletely understood. In this review, we discuss the underlying mechanisms causing mitochondrial dysfunction in ischemic skeletal muscle, including causal evidence in rodent studies, and highlight emerging mitochondrial-targeted therapies that have potential to improve PAD outcomes. Particularly, we will analyze literature data on reactive oxygen species production and potential counteracting endogenous and exogenous antioxidants.

Chronic kidney disease exacerbates ischemic limb myopathy in mice via altered mitochondrial energetics

Chronic kidney disease (CKD) substantially increases the severity of peripheral arterial disease (PAD) symptomology, however, the biological mechanisms remain unclear. The objective herein was to determine the impact of CKD on PAD pathology in mice. C57BL6/J mice were subjected to a diet-induced model of CKD by delivery of adenine for six weeks. CKD was confirmed by measurements of glomerular filtration rate, blood urea nitrogen, and kidney histopathology. Mice with CKD displayed lower muscle force production and greater ischemic lesions in the tibialis anterior muscle (78.1 ± 14.5% vs. 2.5 ± 0.5% in control mice, P < 0.0001, N = 5-10/group) and decreased myofiber size (1661 ± 134 μm2 vs. 2221 ± 100 μm2 in control mice, P < 0.01, N = 5-10/group). This skeletal myopathy occurred despite normal capillary density (516 ± 59 vs. 466 ± 45 capillaries/20x field of view) and limb perfusion. CKD mice displayed a ~50-65% reduction in muscle mitochondrial respiratory capacity in ischemic muscle, whereas control mice had normal mitochondrial function. Hydrogen peroxide emission was modestly higher in the ischemic muscle of CKD mice, which coincided with decreased oxidant buffering. Exposure of cultured myotubes to CKD serum resulted in myotube atrophy and elevated oxidative stress, which were attenuated by mitochondrial-targeted therapies. Taken together, these findings suggest that mitochondrial impairments caused by CKD contribute to the exacerbation of ischemic pathology.

In-hospital outcome of peripheral vascular intervention in dialysis-dependent end-stage renal disease patients

BACKGROUND

The impact of end-stage renal disease (ESRD) on peripheral vascular intervention (PVI) outcome remains incompletely elucidated.

OBJECTIVES

We sought to compare the outcome of PVI in dialysis patients with those with normal kidney function.

METHODS

Using weighted data from the National Inpatient Sample database between 2002 and 2014, we identified all peripheral artery disease (PAD) patients aged ≥18 years that underwent PVI. Multivariate logistic regression analysis was performed to examine in-hospital outcomes.

RESULTS

Of 1,186,192 patients who underwent PVI, 1,066,830 had normal kidney function (89.9%) and 119,362 had ESRD requiring dialysis (10.1%). Critical limb ischemia was more prevalent in dialysis patients (63.2 vs. 34.0%, p < .001). Compared with normal kidney function group, ESRD requiring dialysis was associated with higher in-hospital mortality (1.5 vs. 4.2%, adjusted OR: 2.13 [95% CI: 2.04-2.23]) and longer length of hospital stay (median 3 days, Interquartile range [IQR] (0-6) vs. 7 days, IQR (4-18); p < .001). Dialysis patients had higher incidence of major adverse cardiovascular events (composite of death, myocardial infarction, or stroke; 14.3 vs. 9.8%, p < .001) and net adverse cardiovascular events (composite of MACE, major bleeding, or vascular complications; 40.8 vs. 29.1%, p < .001). ESRD patients less frequently underwent open bypass (5.6 vs. 8.5%, p < .001) and more frequently had major amputation (10.3 vs. 3.0%, p < .001) compared with normal kidney function group.

CONCLUSION

PAD patients on dialysis who underwent PVI have higher rates of mortality and adverse outcomes as compared to those with normal kidney function.

Alprostadil treatment of critical limb ischemia in hemodialysis patients : A retrospective single-center analysis

BACKGROUND

Peripheral artery disease and critical limb ischemia are common in patients undergoing chronic hemodialysis treatment and are associated with a high rate of amputation and mortality. The effect of treatment with prostanoids in this specific group of patients is unknown.

METHODS

A retrospective single-center analysis of hemodialysis patients with critical limb ischemia was performed who were treated with the prostanoid analogue alprostadil as an infusion during hemodialysis in the period from 2000 to 2013. The primary study outcome was a combined end-point including amputation and death 1 year after start of alprostadil. Kaplan-Meier curves were used to describe amputation-free survival and overall survival. A multivariable adjusted Cox proportional hazards model was calculated for the primary outcome.

RESULTS

A total of 86 patients (60 males, 69.7%) were studied. The median alprostadil treatment period was 1.8 months. The 1‑year amputation-free survival was 41%. In 36% of patients an amputation was necessary and 35% died. Despite alprostadil treatment, 36% of the study patients additionally underwent an endovascular procedure and 16% had bypass surgery. Men had a significantly higher amputation rate (45%) than women (15%) (P = 0.009). Male sex and dialysis vintage were significantly associated with an increased risk for primary outcome CONCLUSIONS: Despite treatment with alprostadil the mortality, amputation rate and the need for revascularization procedures in hemodialysis patients with critical limb ischemia remained high. The outcome, however, was comparable with that of other treatment, such as endovascular procedures and bypass surgery. The effect of any current treatment strategy on amputation rate or mortality in that patient group remains uncertain.

The association of race with quality of health in peripheral artery disease following peripheral vascular intervention: The Q-PAD Study

Black patients have a higher prevalence of peripheral artery disease (PAD) than white patients, and also tend to have a greater extent and severity of disease, and poorer outcomes. The association of race with quality of health (QOH) after peripheral vascular intervention (PVI), however, is less well-known. In our study, we hypothesized that after PVI, black patients experience worse QOH than white patients. We retrospectively assessed racial differences in health status using responses to the Peripheral Arterial Questionnaire (PAQ) at baseline (pre-PVI) and up to 6 months following PVI among 387 patients. We used the PAQ summary score (which includes physical limitation, symptoms, social function and quality of life) as a measure of QOH. We compared QOH scores at baseline and at follow-up after PVI between black ( n=132, 34.1%) and white ( n=255, 65.9%) patients. We then computed the change in score from baseline to follow-up for each patient (the delta) and compared the median delta between the two groups. Multivariable regression was used to model the delta QOH after controlling for factors associated with race or with the delta QOH. There was no significant difference in mean QOH by race either at baseline ( p=0.09) or at follow-up ( p=0.45). There was no significant difference in the unadjusted median delta by race (white 25.3 vs black 21.5, p=0.28) and QOH scores improved significantly at follow-up in both groups, albeit the improvement was marginally lower in black compared with white patients after adjustment for baseline confounders ( b = -6.6, p=0.05, 95% CI -13.2, -0.11).

Results for primary bypass versus primary angioplasty/stent for lower extremity chronic limb-threatening ischemia

BACKGROUND

Long-term results comparing percutaneous transluminal angioplasty with or without stenting (PTA/S) and open surgical bypass for chronic limb-threatening ischemia (CLTI) in patients who have had no prior intervention are lacking.

METHODS

All patients undergoing a first-time lower extremity revascularization for CLTI by vascular surgeons at our institution from 2005 to 2014 were retrospectively reviewed. Outcomes included perioperative complications, wound healing, restenosis, primary patency, reintervention, major amputation, RAS events (ie, reintervention, major amputation, or stenosis), and mortality. Outcomes were evaluated using χ², Kaplan-Meier, and Cox regression analyses.

RESULTS

Of the 2869 total lower extremity revascularizations performed between 2005 and 2014, there were 1336 that fit our criteria of a first-time lower extremity intervention for CLTI (668 bypass procedures and 668 PTA/S procedures). Bypass patients were younger (71 vs 72 years; P = .02) and more often male (62% vs 56%; P < .02). Total mean hospital length of stay (LOS) was significantly longer after a first-time bypass (10 vs 8 days; P < .001), as were mean preoperative LOS (4 vs 3 days; P < .01) and postoperative LOS (7 vs 5 days; P < .001). There was no difference in perioperative mortality (3% vs 3%; P = .63). Surgical site infection occurred in 10% of bypass patients. Freedom from reintervention was significantly higher in patients undergoing a first-time bypass procedure (62% vs 52% at 3 years; P = .04), as was freedom from restenosis (61% vs 45% at 3 years; P < .001). Complete wound healing at 6-month follow-up was significantly better after an initial bypass (43% vs 36%; P < .01). A Cox regression model of all patients showed that reintervention was predicted by a first-time PTA/S (hazard ratio, 1.6; 95% confidence interval, 1.3-2.1) and both preoperative femoropopliteal TransAtlantic Inter-Society Consensus (TASC) C and TASC D lesions (2.0 [1.3-3.1] and 1.8 [1.3-2.7], respectively). Major amputation among all patients was predicted by an initial presentation of gangrene (2.5 [1.3-5.0]), dialysis dependence (1.9 [1.3-2.9]), diabetes (2.0 [1.1-3.8]), and preoperative femoropopliteal TASC D lesions (2.1 [1.1-4.0]) and was not predicted by procedure type.

CONCLUSIONS

In this retrospective analysis, bypass for the primary treatment of CLTI showed improved 6-month wound healing, higher freedom from restenosis, improved patency rates, significantly fewer reinterventions, and higher survival than PTA/S within 3 years; however, a bypass-first approach was associated with increased total hospital LOS and wound infection. Perioperative mortality and amputation rates were similar between procedure types.