Loss of kidney function in patients with critical limb ischemia treated endovascularly or surgically

Perioperative complications of minor and major reinterventions for peripheral arterial disease

IntroductionPatients with peripheral arterial disease (PAD) frequently require reinterventions after lower-extremity revascularization (LER) to maintain perfusion. Current Society for Vascular Surgery guidelines define reinterventions as major or minor based on the magnitude of the procedure. While prior studies have compared primary LER procedures of different magnitudes, similar studies for reinterventions have not been performed. The objective of this study is to compare perioperative outcomes associated with major and minor reinterventions.MethodsPatients undergoing LER for PAD at a tertiary care center from 2013 to 2017 were included. A retrospective review of electronic medical records was performed, and reinterventions were categorized as major or minor based on the procedure magnitude. Minor reinterventions included endovascular procedures and open revision with patch angioplasty, while major reinterventions were characterized by open surgical or endovascular LER with catheter-directed thrombolysis (CDT). Perioperative outcomes following LER were captured and compared for major and minor reinterventions. An additional subgroup analysis was performed comparing outcomes associated with major reinterventions stratified into open major surgical reinterventions and CDT.ResultsThis study included 713 patients over a mean follow-up of 2.5 years. A total of 291 patients underwent 696 ipsilateral reinterventions (range = 1-12 reinterventions). Most reinterventions were minor (72.1%, N = 502) and 27.9% (N = 194) were major. Patients receiving reinterventions had an average age of 67.2 ± 11.5 and most were white (73.5%) males (60.1%) initially treated for claudication (58.2%) and CLTI (41.8%). There was significantly higher post-operative bleeding (9.8% vs 3.4%, p = .001), arterial thrombosis (3.1% vs 1.0%, p = .047), and acute renal failure (6.2% vs 2.4%, p = .014) after major reinterventions than minor. Additionally, major reinterventions had significantly higher return to the OR (17.0% vs 11.3%, p = .046) and longer hospital stays (7.5 vs 4.3 days, p = <.0001). Overall, major reinterventions were associated with significantly increased perioperative morbidity (37.6% vs 19.7%, p ≤ .001) with no difference in perioperative mortality. In the subgroup analysis, open reinterventions resulted in significantly longer hospital stays (8.6 days vs 5.5 days, p ≤ .001) and more wound infections than CDT (11.0% vs 0%, p = .017). However, there was no other significant difference in morbidity or mortality following treatment with open surgical reinterventions or CDT.ConclusionsIn this study, major reinterventions after LER were associated with greater perioperative morbidity than minor reinterventions, with no difference in mortality. Major reinterventions performed via open surgery and CDT had similar morbidity and mortality.

Comparing the efficacy and safety of endovascular therapy versus surgical revascularization for critical limb-threatening ischemia: A systematic review and Meta-analysis

INTRODUCTION

Critical limb-threatening ischemia (CLTI) is a severe manifestation of peripheral artery disease (PAD) that can lead to limb amputation and significantly reduce quality of life. In addition to guideline-directed medical therapy (GDMT), endovascular therapy and surgical revascularization are the two revascularization options for CLTI. In recent years, there has been an ongoing debate about the best approach for CLTI patients. The purpose of this meta-analysis is to examine the current evidence and compare the clinical outcomes of endovascular therapy and surgical revascularization for CLTI.

METHODS

We conducted a systematic search of electronic databases (PubMed, Embase, Cochrane Library, and Web of Science) for studies comparing the outcomes of endovascular therapy versus surgery in patients with CLTI. The primary outcomes were major adverse limb events (MALE) and major adverse cardiovascular events (MACE), while secondary outcomes included risk of bleeding, wound complications, readmission, unplanned reoperation, acute renal failure, and length of hospital stay. Pooled data was analyzed using the fixed-effect model or the random-effect model in Review Manager 5.3. The Newcastle-Ottawa Scale and Cochrane risk of bias assessment tool were used to assess the bias of included studies.

RESULTS

A total of 16 studies (47,609 patients) were included in this meta-analysis. The overall effect favors surgery over endovascular intervention in terms of MALE [odds ratio (OR) 1.13, 95% CI (1.01-1.28), P = 0.04]. Endovascular therapy is associated with lower MACE rates compared to surgery [OR 0.62, 95% CI (0.51-0.76), P < 0.00001]. Furthermore, the risk of bleeding, wound complications, readmission, unplanned reoperation, acute renal failure as well as the length of hospital stay was lower for endovascular intervention. Finally, there was no statistically significant difference in 30-day mortality between the two groups [OR 0.94, 95% CI 0.79-1.12, P = 0.52; Fig. 3i], and the pooled studies were homogeneous [P = 0.39; I2 = 5%].

CONCLUSION

Surgery may be the preferred treatment option for CLTI patients, as it is associated with a lower risk of MALE than endovascular therapy. However, endovascular therapy may be associated with a lower risk of MACE and lower rates of bleeding, wound complications, readmission, unplanned reoperation, acute renal failure, and shorter hospital stays. There was no statistically significant difference in 30-day mortality between the two groups. Ultimately, the decision to use endovascular therapy or surgery as the primary treatment strategy should be based on a multi-disciplinary team approach with careful consideration of patient characteristics and anatomy.

Protective effects of safranal on kidney tissue in a rat model of distant ischemia-reperfusion injury with infrarenal aortic occlusion

Background/aim

Ischemia-reperfusion (IR) injury to a part of the body can cause damage to distant organs such as the kidney and heart. This study investigated the protective effects of safranal against IR-induced renal injury.

Materials and methods

Used in this study were 24 Wistar Albino male rats, which were divided into 3 equal and randomised groups. The sham group underwent laparotomy only. In the IR group, the infrarenal aorta was clamped for 1 h, and then reperfused for 2 h. In the IR-safranal group, safranal was administered 30 min before the procedure and IR injury was induced in the same way as in the IR group. After the procedure, blood and tissue samples were collected from the rats for biochemical and histopathological analyses. Antioxidant capacity and proinflammatory cytokine analyses were performed on the blood samples. Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining was performed to determine the number of cells undergoing apoptosis in the kidney tissue.

Results

The estimated glomerular filtration rate, an indicator of renal function, was lower in the IR group (p1 = 0.024 vs. p3 = 0.041, respectively) compared to the other groups, while creatinine levels were higher in the IR group compared to the other groups (p1 = 0.032 vs. p2 = 0.044, respectively). The blood urea nitrogen level was higher in the IR group than in the other groups (p1 = 0.001vs p2 = 0.035, respectively). The total antioxidant and total oxidant status, indicating tissue oxidative stress, did not differ between groups (p = 0.914 vs. p = 0.184, respectively). Among the proinflammatory cytokines, the interleukin-1β (IL-1β) and IL-6 levels were significantly higher in the IR group (p = 0.034 vs. p = 0.001, respectively), but the tumour necrosis factor-α (p = 0.19), and interferon-γ (p = 0.311) levels did not differ between groups. Histopathological examination showed significantly less damage to glomerular and tubular cells in the IR-safranal group (p < 0.001). The number of TUNEL-positive cells was higher in the IR group compared to the other groups (p < 0.001).

Conclusion

Safranal may have protective effects against kidney damage caused by distant ischemia-reperfusion injury.

Home-Based Exercise in Elderly Patients with Claudication and Chronic Kidney Disease Is Associated with Lower Progressive Renal Function Worsening: A 5-Year Retrospective Study

This observational study aimed to monitor the 5-year trends of kidney function in patients with peripheral artery disease (PAD) and concomitant chronic kidney disease (CKD) enrolled or not enrolled into a rehabilitative exercise program. Sixty-six patients (aged 72 ± 10, males n = 52) at KDOQI stages III-IV and PAD at Rutherford's stage I-III were included in the study, with a group (Exercise, EX; n = 32) receiving a 6-month structured pain-free home-based walking program and a group (Control, CO; n = 34) receiving walking advice and optimal nephrological care. Outcomes included kidney function measured through serum creatinine (sCr) and clinical outcomes, including the rate of advance of CKD stages and admission to dialysis, revascularizations, and hospitalizations. At baseline, the two groups were comparable for age, nephropathy, medications, comorbidities, and PAD severity. Patients in the EX group safely completed the exercise program. SCr values were slightly increased in EX (baseline: 2.35 ± 0.32; 5-year: 2.71 ± 0.39 mg/dL) and progressively worsened in CO (baseline: 2.30 ± 0.31; 5-year 4.22 ± 0.42 mg/dL), with a significant between-group difference (p = 0.002). The control group also showed a higher number of dialysis admissions (5 vs. 0, p = 0.025) and advancing CKD stage as well a higher risks for lower limb revascularization (hazard ratio: 2.59; 95%CI: 1.11-6.02; p = 0.027) and for all-cause hospitalization (hazard ratio: 1.77; 95%CI: 1.05-2.97; p = 0.031). PAD-CKD patients enrolled in a low-moderate intensity home-exercise program showed more favorable long-term trends in kidney function and clinical outcomes than patients with usual care. These preliminary observations need to be confirmed in randomized trials.

Acute Kidney Injury Following In-Patient Lower Extremity Vascular Intervention: From the National Cardiovascular Data Registry

OBJECTIVES

The authors analyzed data from the NCDR (National Cardiovascular Data Registry) PVI Registry and defined acute kidney injury (AKI) as increased creatinine of ≥0.3 mg/dl or 50%, or a new requirement for dialysis after PVI.

BACKGROUND

AKI is an important and potentially modifiable complication of peripheral vascular intervention (PVI). The incidence, predictors, and outcomes of AKI after PVI are incompletely characterized.

METHODS

A hierarchical logistic regression risk model using pre-procedural characteristics associated with AKI was developed, followed by bootstrap validation. The model was validated with data submitted after model creation. An integer scoring system was developed to predict AKI after PVI.

RESULTS

Among 10,006 procedures, the average age of patients was 69 years, 58% were male, and 52% had diabetes. AKI occurred in 737 (7.4%) and was associated with increased in-hospital mortality (7.1% vs. 0.7%). Reduced glomerular filtration rate, hypertension, diabetes, prior heart failure, critical or acute limb ischemia, and pre-procedural hemoglobin were independently associated with AKI. The model to predict AKI showed good discrimination (optimism corrected c-statistic = 0.68) and calibration (corrected slope = 0.97, intercept of -0.07). The integer point system could be incorporated into a useful clinical tool because it discriminates risk for AKI with scores ≤4 and ≥12 corresponding to the lower and upper 20% of risk, respectively.

CONCLUSIONS

AKI is not rare after PVI and is associated with in-hospital mortality. The NCDR PVI AKI risk model, including the integer scoring system, may prospectively estimate AKI risk and aid in deployment of strategies designed to reduce risk of AKI after PVI.

Successful Peripheral Vascular Intervention in Patients with High-risk Comorbidities or Lesion Characteristics

PURPOSE OF REVIEW

Certain comorbidities and lesion characteristics are associated with increased risk for procedural complications, limb events, and cardiovascular events following peripheral vascular intervention (PVI) in patients with peripheral arterial disease (PAD). The purpose of this review is to provide an overview of high-risk modifiable and unmodifiable patient characteristics and its relative impact on clinical outcomes such as amputation risk and mortality. Furthermore, general approaches to potentially mitigating these risks through pre-intervention planning and use of modern devices and techniques are discussed.

RECENT FINDINGS

Diabetes, tobacco use, and older age remain strong risk factors for the development of peripheral arterial disease. Recent data highlight the significant risk of polyvascular disease on major limb and cardiac events in advanced PAD, and ongoing studies are assessing this risk specifically after PVI. Challenging lesion characteristics such as calcified disease and chronic total occlusions can be successfully treated with PVI by utilizing novel devices (e.g., intravascular lithotripsy, re-entry devices) and techniques (e.g., subintimal arterial "flossing" with antegrade-retrograde intervention). Understanding high-risk patient comorbidities and lesion characteristics will improve our ability to counsel and manage patients with advanced PAD. Continued device innovation and novel techniques will aid in procedural planning for successful interventions to improve clinical outcomes.

Discrepancy in Outcomes after Revascularization for Chronic Limb-Threatening Ischemia Warrants Separate Reporting of Rest Pain and Tissue Loss

BACKGROUND

Chronic limb-threatening ischemia (CLTI) manifests as rest pain (RP) and tissue loss (TL). Outcomes of lower extremity revascularization (LER) for CLTI have traditionally been evaluated as a single entity and compared with claudication. We hypothesize that patients presenting with TL have worse short-term outcomes after LER, compared to patients with RP.

METHODS

The National Inpatient Sample was reviewed between 2009 and 2013. All patients undergoing LER for TL and RP were identified. Patient characteristics, Charlson Comorbidity Index (CCI), length of stay, rates of inpatient major amputation, and mortality after LER were noted. Multivariable regression analysis was performed to identify predictors of inpatient mortality and major amputation between the 2 groups.

RESULTS

A total of 218,628 patients underwent LER (RP = 76,108, TL = 142,519). Patients with TL were more likely to undergo endovascular LER (RP = 31.3% vs. TL = 48.7%; P < 0.001). Patients with TL had higher comorbidities as suggested by increased likelihood of having CCI ≥3 (RP = 22.9% vs. TL = 40.3%; P < 0.001). The mean costs were significantly higher in the TL group (RP = $23,795 vs. TL = $31,470; P < 0.001). There was a significantly higher rate of major amputation (RP = 1.3% vs. TL = 6.6%; P < 0.001) and inpatient mortality (RP = 0.9% vs. TL = 1.9%; P < 0.001) after LER for TL. On multivariable analysis, TL was independently associated with increased major amputation (odds ratio [OR] 4.93, 95% confidence interval [CI] 4.18-5.81) and increased mortality (OR 1.42, 95% CI 1.16-1.74) compared to RP.

CONCLUSIONS

There is significant discrepancy in outcomes of LER for TL and RP. TL is independently associated with major amputation and inpatient mortality. Outcomes of LER for TL and RP should be reported separately for better benchmarking.

Acute Renal Failure/Acute Kidney Injury (AKI) Associated with Endovascular Procedures

AKI is one of the most common yet underdiagnosed postoperative complications that can occur after any type of surgery. Contrast-induced nephropathy (CIN) is still poorly defined and due to a wide range of confounding individual variables, its risk is difficult to determine. CIN mainly affects patients with underlying chronic kidney disease, diabetes, sepsis, heart failure, acute coronary syndrome and cardiogenic shock. Further research is necessary to better understand pathophysiology of contrast-induced AKI and consequent implementation of effective prevention and therapeutic strategies. Although many therapies have been tested to avoid CIN, the only potent preventative strategy involves aggressive fluid administration and reduction of contrast volume. Regardless of surgical technique—open or endovascular—perioperative AKI is associated with significant morbidity, mortality and cost. Endovascular procedures always require administration of a contrast media, which may cause acute tubular necrosis or renal vascular embolization leading to renal ischemia and as a consequence, contribute to increased number of post-operative AKIs.

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.

Epidemiology, outcomes, and management of acute kidney injury in the vascular surgery patient

OBJECTIVE

Conventional clinical wisdom has often been nihilistic regarding the prevention and management of acute kidney injury (AKI), despite its being a frequent and morbid complication associated with both increased mortality and cost. Recent developments have shown that AKI is not inevitable and that changes in management of patients can reduce both the incidence and morbidity of perioperative AKI. The purpose of this narrative review was to review the epidemiology and outcomes of AKI in patients undergoing vascular surgery using current consensus definitions, to discuss some of the novel emerging risk stratification and prevention techniques relevant to the vascular surgery patient, and to describe a standardized perioperative pathway for the prevention of AKI after vascular surgery.

METHODS

We performed a critical review of the literature on AKI in the vascular surgery patient using the PubMed and MEDLINE databases and Google Scholar through September 2017 using web-based search engines. We also searched the guidelines and publications available online from the organizations Kidney Disease: Improving Global Outcomes and the Acute Dialysis Quality Initiative. The search terms used included acute kidney injury, AKI, epidemiology, outcomes, prevention, therapy, and treatment.

RESULTS

The reported epidemiology and outcomes associated with AKI have been evolving since the publication of consensus criteria that allow accurate identification of mild and moderate AKI. The incidence of AKI after major vascular surgery using current criteria is as high as 49%, although there are significant differences, depending on the type of procedure performed. Many tools have become available to assess and to stratify the risk for AKI and to use that information to prevent AKI in the surgical patient. We describe a standardized clinical assessment and management pathway for vascular surgery patients, incorporating current risk assessment and preventive strategies to prevent AKI and to decrease its complications. Patients without any risk factors can be managed in a perioperative fast-track pathway. Those patients with positive risk factors are tested for kidney stress using the urinary biomarker TIMP-2•IGFBP7, and care is then stratified according to the result. Management follows current Kidney Disease: Improving Global Outcomes guidelines.

CONCLUSIONS

AKI is a common postoperative complication among vascular surgery patients and has a significant impact on morbidity, mortality, and cost. Preoperative risk assessment and optimal perioperative management guided by that risk assessment can minimize the consequences associated with postoperative AKI. Adherence to a standardized perioperative pathway designed to reduce risk of AKI after major vascular surgery offers a promising clinical approach to mitigate the incidence and severity of this challenging clinical problem.

Percutaneous Vascular Interventions Versus Bypass Surgeries in Patients With Critical Limb Ischemia: A Comprehensive Meta-analysis

OBJECTIVE

The aim of our study was to compare percutaneous vascular interventions (PVI) versus bypass surgeries (BSX) in patients with critical limb ischemia (CLI).

BACKGROUND

Previous relevant reviews with limited numbers of included studies did not strictly confine the inclusion criteria to CLI, also involving patients with severe claudication, which may introduce bias in the decision-making of CLI revascularization. Current treatment strategies for CLI still remain controversial.

METHODS

We performed a meta-analysis of all available randomized controlled trials and observational clinical studies comparing PVI with BSX in CLI patients. Primary endpoints included overall survival, amputation-free survival, 30-day mortality, and major adverse cardiovascular and cerebrovascular events.

RESULTS

We identified 45 cohorts and 1 RCT in over 20,903 patients. In overall population, PVI reduced the risks of 30-day mortality [odds ratio (OR) 0.69, 95% confidence interval (CI) 0.51-0.95), major adverse cardiovascular and cerebrovascular events (OR 0.42, 95% CI 0.29-0.61), and surgical site infection (OR 0.31, 95% CI 0.19-0.51), but increased the risks of long-term all-cause mortality [hazard ratio (HR) 1.16, 95% CI 1.05-1.27) and primary patency failure (HR 1.31, 95% CI 1.08-1.58). When compared with autogenous BSX, PVI was also associated with additional increased risks of long-term death or amputation (HR 1.41, 95% CI 1.02-1.94) and secondary patency failure (HR 1.51, 95% CI 1.17-1.95). In patients with infrapopliteal lesions, we found PVI had inferior primary patency (HR 1.39, 95% CI 1.10-1.75) compared with BSX.

CONCLUSION

For patients in good physical condition with long life-expectancy, BSX may represent a better choice compared with PVI, particularly when autogenous bypass is available. While enhanced perioperative care for cardiovascular events and surgical site should be considered in patients underwent BSX to achieve comparable short-term outcomes provided by PVI.

One-Year Results of First-Line Treatment Strategies in Patients With Critical Limb Ischemia (CRITISCH Registry)

PURPOSE

To examine the outcomes of all first-line strategies for the treatment of critical limb ischemia (CLI), identify factors that influenced the treatment choice, and determine the risk of amputation or death after each treatment.

METHODS

CRITISCH ( ClinicalTrials.gov identifier NCT01877252) is a multicenter, national, prospective registry evaluating all available treatment strategies applied in 1200 consecutive CLI patients in 27 vascular centers in Germany. The recruitment started in January 2013 and was completed in September 2014. Treatment options were endovascular revascularization (642, 53.5%), bypass surgery (284, 23.7%), femoral artery patchplasty (126, 10.5%) with or without concomitant peripheral intervention, conservative treatment (118, 9.8%), and primary major amputation (30, 2.5%). The primary endpoint of this study was amputation-free survival (AFS). The Society of Vascular Surgery's suggested objective performance goal (OPG) for AFS (71%) was used as the effectiveness criterion. Multivariable regression methods were employed to identify variables that influenced the treatment selection and AFS after each treatment; results are presented as the hazard ratio (HR) and 95% confidence interval (CI).

RESULTS

The 12-month AFS estimates following endovascular therapy, bypass grafting, femoral patchplasty, and conservative treatment were 75%, 72%, 73%, and 72%, respectively. Factors influencing treatment choice were age, chronic kidney disease (CKD), diabetes, smoking, prior vascular procedures in the index leg, TransAtlantic Inter-Society Consensus II C/D lesions, and absence of runoff vessels. Cox regression analysis identified CKD (HR 2.07, 95% CI 1.26 to 3.41, p=0.004), the use of a prosthetic bypass conduit (HR 1.97, 95% CI 1.23 to 3.14, p=0.004), and previous vascular intervention in the index limb (HR 1.52, 95% CI 0.94 to 2.43, p=0.085) as independent risk factors for diminished AFS after bypass surgery. CKD (HR 1.47, 95% CI 1.09 to 1.99, p=0.012) and Rutherford category 6 (HR 1.81, 95% CI 1.30 to 2.52, p<0.001) compromised the performance of endovascular revascularization.

CONCLUSION

CRITISCH registry data revealed that all first-line treatment strategies selected and indicated by the treating physicians met the suggested OPGs. CKD was an important determinant of patient prognosis after treatment regardless of the revascularization method.