Bypass vs. Endovascular Therapy of Infrapopliteal Lesions for Critical Limb Ischemia

Information Conversion in Measuring Channels with Optoelectronic Sensors

The purpose of this work is the authors' attempt to identify the main phases of information transformation in measurement channels on the example of an optical measurement channel with microprocessor control. The authors include such phases: hardware implementation and analytical representation of an optical sensor's converting functions and a current-to-voltage converter; based on the methods of experimental computer science, the converting functions and sensitivity are deduced, analytical dependences for estimation of a range of measurement are obtained. It is shown that the choice of information transmission type in the microprocessor measuring channel significantly affects the speed of the measuring channel. Based on the uncertainty in the form of entropy before and after measurements, the amount of information for measuring channels with optoelectronic sensors is estimated. The application of the results obtained in the work allows even at the design stage of physical and mathematical modeling to assess the basic static metrological characteristics of measuring channels, aimed at reducing the stage of development and debugging of hardware and software and standardization of their metrological characteristics.

A Propensity-Matched Analysis of Endovascular Intervention versus Open Nonautologous Bypass as Initial Therapy in Patients with Chronic Limb-Threatening Ischemia

OBJECTIVES

Endovascular therapies are increasingly used in patients with complex multilevel disease and chronic limb-threatening ischemia (CLTI). Infrageniculate bypass with autologous vein conduit is considered the gold standard in these patients. However, many patients often lack optimal saphenous vein, leading to the use of nonautologous prosthetic conduit. We compared limb salvage and survival rates for patients with CLTI undergoing first time revascularization with either open nonautologous conduit or endovascular intervention.

METHODS

We retrospectively reviewed consecutive patients undergoing first time endovascular or open surgical revascularization at our institution between 2009 and 2016. Patients were divided into endovascular intervention or open bypass with nonautologous conduit (NAC) cohorts. Primary endpoints were amputation-free survival (AFS), freedom from reintervention, primary patency, and overall survival. Propensity scoring was used to construct matched cohorts. Outcomes were evaluated using Kaplan-Meier and Cox Proportional Hazards models.

RESULTS

A total of 125 revascularizations were identified. There were 65 endovascular interventions and 60 NAC bypasses. In unmatched analysis, there was an elevated risk of perioperative MI (7% vs. 0%, P = 0.05) and amputation (10% vs. 2%, P = 0.04) for the NAC groups compared to the endovascular group. In matched analysis, endovascular patients had a lower incidence of 30-day amputation (1.5% vs. 10% P = 0.04) and length of stay (median days, 1 vs. 9, P < 0.01) compared to the open cohort. While not statistically significant, the endovascular group trended towards increased rates of two-year AFS (76% vs. 65%, P = 0.07) compared to the NAC group. There was no significant difference in overall survival when the endovascular cohort was compared to NAC (85% vs. 77%, P = 0.29) patients. In matched Cox analysis, nonautologous conduit use was associated with an increased risk of limb loss (HR 2.03, 95% CI 0.94-4.38, P = 0.07) compared to endovascular revascularization.

CONCLUSIONS

An "endovascular first" approach offers favorable perioperative outcomes and comparable AFS compared to NAC and may be preferable when autologous conduit is unavailable.

Comparison of Bypass and Endovascular Intervention for Popliteal Occlusion with the Involvement of Trifurcation for Critical Limb Ischemia

BACKGROUND

The aim of this study is to analyze the technical aspects and outcomes of the treatment of occlusion of the popliteal artery with the involvement of the trifurcation treated with a bypass (open) and endovascular (endo) approach.

METHODS

Overall, 108 consecutive procedures were enrolled retrospectively. Patients were evaluated in 2 groups: the endo group (65 patients) and the open group (43 patients). Primary outcome were MALE (major adverse limb events), amputation-free survival, and early mortality (until 30 days). Secondary outcome was overall survival in 3 years. Inclusion criteria were Rutherford 4 and 5 and occlusion of the popliteal artery with the involvement of trifurcation and, at least, 1 infrapopliteal artery of runoff.

RESULTS

Technical success was achieved in 100% of patients in the open and 96.9% of patients in the endo group. Freedom from MALE was 73.5% and 68.5% for 1 and 3 years respectively for the endo group, and 84.3% and 77.2% respectively for the open group (P = 0.413). Considering the total number of major reinterventions executed until 3 years, the reinterventions was statistically more performed in the endo compared to the open group (P = 0.0459). Amputation-free survival for the endo group in 30 days, 1 year, and 3 years was 93.7%, 79.3%, and 66.0%, respectively, and the amputation-free survival for the open group was 88.4%, 77.4%, and 64.3% (P = 0.726). Early mortality was 9.3% for the open group and 1.5% for the endo group (P = 0.060). In 3 years, the overall survival was 75.1% in the open group and 84.3% in the endo group.

CONCLUSIONS

In 3 years, follow-up endovascular treatment of occlusion of the popliteal artery with the involvement of the trifurcation has similar time freedom from MALE compared to open approach. Overall and amputation-free survival was not different between the groups besides more reinterventions in patients who underwent endovascular approach.

External validation of CLI Frailty Index and assessment of predictive value of modified CLI Frailty Index for patients with critical limb ischemia undergoing infrainguinal revascularization

Objectives

CLI Frailty is a useful diagnostic criterion of frailty in patients with critical limb ischemia (CLI). It is important to evaluate not only comorbidities but also frailty in decision making to select the type of treatment for CLI patients. The purposes of our study were to externally validate the CLI Frailty Index and to evaluate the modified CLI Frailty Index by measurement of skeletal muscle mass using computed tomography.

Methods

Patients who underwent preoperative computed tomography examination and infrainguinal revascularization between 2002 and 2015 were retrospectively analyzed. A patient was defined as CLI Frailty (+), if two or more of the following criteria were present: low Geriatric Nutritional Risk Index (GNRI), low skeletal muscle mass index (SMI) evaluated by prediction equations, and non-ambulatory status. For the modified CLI Frailty Index, skeletal muscle area was measured by computed tomography instead of prediction equations.

Results

During the study period, 226 patients with CLI underwent revascularization; we included 127 patients and excluded 99 patients who were treated only with iliac revascularization or did not undergo CT scans. The overall survival at two years after revascularization was 83.6% for the CLI Frailty (−) group versus 63.2% for the CLI Frailty (+) group ( P = .02). The overall survival at two years after revascularization was 89.7% for the modified CLI Frailty (−) group versus 60.5% for the modified CLI Frailty (+) group ( P < .01). Multivariate analysis 1 including CLI Frailty revealed that hemodialysis (HR, 3.71; 95% CI, 1.58–8.83; P < .01), CLI Frailty (HR, 3.22; 95% CI, 1.35–7.47; P < .01) and cerebrovascular disease (HR, 2.58; 95% CI, 1.09–5.91; P = .03) were risk factors for overall survival two years after revascularization. In multivariate analysis 2 including modified CLI Frailty, modified CLI Frailty (HR, 5.92; 95% CI, 2.49–15.7; P < .01), hemodialysis (HR, 4.03; 95% CI, 1.65–10.0; P < .01) and diabetes mellitus (HR, 0.41; 95% CI, 0.16–0.99; P = .05) were risk factors for overall survival two years after revascularization.

Conclusions

Both the CLI Frailty and the modified CLI Frailty Indexes were useful in predicting the two-year overall survival of patients with CLI after infrainguinal revascularization. Although the measurement of skeletal muscle mass using computed tomography may accurately predict two-year overall survival, SMI prediction is effective for patients with CLI who did not undergo preoperative CT.

Major adverse limb events and major adverse cardiac events after contemporary lower extremity bypass and infrainguinal endovascular intervention in patients with claudication

OBJECTIVE

Major adverse limb events (MALEs) and major adverse cardiovascular events (MACEs) at 30 days provide standardized metrics for comparison and have been adopted by the Society for Vascular Surgery's objective performance goals for critical limb ischemia. However, MALEs and MACEs have not been widely adopted within the claudication population, and the comparative outcomes after lower extremity bypass (LEB) and infrainguinal endovascular intervention (IEI) remain unclear. The purpose of this study was to compare MALEs and MACEs after LEB and IEI in a contemporary national cohort and to determine predictors of MALEs and MACEs after revascularization for claudication.

METHODS

A national data set of LEB and IEI performed for claudication was obtained using National Surgical Quality Improvement Program vascular targeted Participant Use Data Files from 2011 to 2014. Patients were stratified by LEB vs IEI and compared by appropriate univariate analysis. The primary outcomes were MALE (defined as untreated loss of patency, reintervention on the index arterial segment, or amputation of the index limb) and MACE (defined as stroke, myocardial infarction, or death). Multivariable logistic regression was used to identify predictors of MALEs and MACEs.

RESULTS

A total of 3925 infrainguinal revascularization procedures (2155 LEB and 1770 IEI) were performed for claudication. There was no difference in 30-day MALEs between LEB and IEI (4.0% vs 3.2%; P = .17). On multivariable logistic regression, predictors of 30-day MALEs included tibial revascularization (odds ratio [OR], 2.2; P < .0001) and prior LEB on the same arterial segment (OR, 1.8; P = .004). LEB had significantly higher 30-day MACEs (2.0% vs 1.0%; P = .01) but similar mortality (0.5% vs 0.4%; P = .6). Predictors of MACEs included LEB vs IEI (OR, 2.1; P = .01), chronic obstructive pulmonary disease (OR, 2.2; P = .01), dialysis dependence (OR, 4.4; P = .003), and diabetes (OR, 1.9; P = .02).

CONCLUSIONS

In this large national cohort, LEB and IEI for claudication are associated with similar 30-day MALEs. Tibial revascularization and revascularization after prior failed bypass predict MALEs in claudicants and should therefore be undertaken with caution. LEB was associated with more 30-day MACEs but comparable 30-day mortality compared with IEI. Patients with end-stage renal disease, chronic obstructive pulmonary disease, and diabetes are at high risk for MACEs. The risk of 30-day MACEs after LEB should be weighed against the longer term outcomes of LEB vs IEI and conservative management, particularly in these higher risk patients. This analysis helps define contemporary 30-day outcomes after infrainguinal revascularization performed for claudication and serves as a baseline with which the short-term outcomes of future treatments can be compared.

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.

Bypass Surgery after Endovascular Therapy for Infrapopliteal Lesion Is Not a Poor Outcome Compared with Initial Bypass Surgery by Vascular Surgeons

BACKGROUND

It is unclear whether prior endovascular therapy (EVT) adversely affects bypass surgery. The aim of this study is to investigate treatment outcomes between initial bypass (bypass-first) and bypass surgery after EVT (EVT-first).

METHODS

We conducted a retrospective analysis of critical limb ischemia patients undergoing infrapopliteal bypass between November 2006 and December 2015. Graft patency, limb salvage (LS), amputation-free survival (AFS), and overall survival (OS) were examined between bypass-first and EVT-first groups.

RESULTS

The subjects in this study were 75 patients and 82 limbs in the bypass-first group and 24 patients and 24 limbs in the EVT-first group. The average age was higher in EVT-first group (P = 0.03). The percentage of inframalleolar bypass was higher in the EVT-first group (P = 0.002). Primary patency at 1 and 2 years was 72.0% and 67.5% for the bypass-first group and 53.1% and 47.2% for the EVT-first group, respectively (P = 0.04). Inframalleolar bypass was a risk factor for lower primary patency (hazard ratio 3.07, 95% confidence interval 1.18-8.51, P = 0.02) in multivariate analysis, while there were no differences in secondary patency, LS, AFS, and OS.

CONCLUSIONS

Bypass surgery after EVT has lower primary patency rates in comparison with primary bypass in patients submitted to infrapopliteal revascularization. Although very heterogeneous study population with a lot of bias in the indication of the revascularization, LS, OS and AFS are not affected by previous EVT.

Lower extremity bypass for critical limb ischemia decreases major adverse limb events with equivalent cardiac risk compared with endovascular intervention

OBJECTIVE

Lower extremity bypass (LEB) has traditionally been the "gold standard" in the treatment of critical limb ischemia (CLI). Infrainguinal endovascular intervention (IEI) has become more commonly performed than LEB, but comparative outcomes are limited. We sought to compare rates of major adverse limb events (MALEs) and major adverse cardiovascular events (MACEs) after LEB and IEI in a propensity score-matched, national cohort of patients with CLI.

METHODS

The National Surgical Quality Improvement Program (NSQIP) vascular targeted files (2011-2014) for LEB and IEI were merged. CLI patients were identified by ischemic rest pain or tissue loss. Patients were matched on a 1:1 basis for propensity to undergo LEB or IEI. Primary outcomes were 30-day MALEs and MACEs. Within the propensity-matched cohort, multivariate logistic regression was used to identify independent predictors of MALEs and MACEs.

RESULTS

A total of 13,294 LEBs and IEIs were identified, with 8066 cases performed for CLI. Propensity matching identified 3848 cases (1924 per group). There were no differences in preoperative variables between the propensity-matched LEB and IEI groups (all P > .05). At 30 days, rates of MALEs were significantly lower in the LEB group (9.2% LEB vs IEI 12.2%; P = .003). On multivariate logistic regression, bypass with single-segment saphenous vein vs IEI (odds ratio [OR], 0.7; 95% confidence interval [CI], 0.54-0.92; P = .01), bypass with alternative conduit (prosthetic, spliced vein, or composite) vs IEI (OR, 0.7; 95% CI, 0.56-0.98; P = .04), antiplatelet therapy (OR, 0.8; 95% CI, 0.58-1.00; P = .049), and statin therapy (OR, 0.8; 95% CI, 0.62-0.99; P = .04) were protective against MALEs, whereas infrageniculate intervention (OR, 1.4; 95% CI, 1.09-1.72; P = .01) and a history of prior bypass of the same arterial segment (OR, 1.8; 95% CI, 1.41-2.41; P <. 0001) were predictive. Rates of 30-day MACEs were not significantly different (4.9% LEB vs 3.7% IEI; P = .07) between the groups. Independent predictors of MACEs included age (OR, 1.02; 95% CI, 1.01-1.04; P = .01), steroid use (OR, 1.8; 95% CI, 1.08-2.99; P = .03), congestive heart failure (OR, 1.7; 95% CI, 1.00-1.96; P = .02), beta blocker use (OR, 1.6; 95% CI, 1.09-1.43; P = .01), dialysis (OR, 2.3; 95% CI, 1.55-3.45; P < .0001), totally dependent functional status (OR, 3.1; 95% CI, 1.25-7.58; P = .02), and suboptimal conduit for LEB compared with IEI (OR, 1.6; 95% CI, 1.08-2.36; P = .02).

CONCLUSIONS

Within this large, propensity-matched, national cohort, LEB predicted lower risk-adjusted 30-day MALE rate compared with IEI. Furthermore, there was no difference in 30-day MACE rate between the groups despite higher inherent risk with open surgical procedures. Therefore, this study supports the effectiveness and primacy of LEB for revascularization in CLI.

A Comparison of Outcomes in Patients with Infrapopliteal Disease Randomised to Vein Bypass or Plain Balloon Angioplasty in the Bypass vs. Angioplasty in Severe Ischaemia of the Leg (BASIL) Trial

OBJECTIVE

The aim was to compare outcomes in a subgroup of patients with infrapopliteal (IP) disease randomised to infrapopliteal vein bypass (VB) or plain balloon angioplasty (PBA) in the original BASIL trial.

METHODS

A comparison of outcomes from patients randomised to VB or PBA undergoing revascularisation for severe limb ischaemia (SLI) because of IP disease with or without femoropopliteal disease. Data were extracted from case report forms from the BASIL trial. The primary outcome was amputation free survival (AFS); secondary outcomes included overall survival (OS), 30 day mortality and morbidity, freedom from arterial re-intervention, immediate technical success, repeat and crossover interventions, length of hospital stay, and quality of revascularisation.

RESULTS

A total of 104 patients were identified in the BASIL study with IP disease, 56 randomised to IP VB, and 48 to IP PBA. Groups were similar at baseline except for more chronic kidney disease and non-steroidal anti-inflammatory drug use in the VB group, and more previous surgical arterial intervention and antihypertensive use in the PBA group. There were no statistically significant differences in AFS or OS; however, clinically important trends were apparent in favour of a VB first strategy. Patients allocated to VB demonstrated significantly quicker relief of rest pain when compared with PBA (p = .005), but no significant differences in improved tissue healing. Median length of index hospital admission was significantly greater in the VB than in the PBA group (18 vs. 10 days, p < .0001) but there was no difference between the two groups in median total hospital stay between randomisation and the primary endpoint (VB 43.5 vs. PBA 42 days).

CONCLUSIONS

Further randomised trials, like BASIL-2 and BEST-CLI, are required to determine whether patients with severe limb ischaemia who require IP revascularisation and who are suitable for VB should have bypass or endovascular intervention as their primary revascularisation procedure.

Risk factors for wound complications and 30-day mortality after major lower limb amputations in patients with peripheral arterial disease

Purpose Risk factors for wound complications or 30-day mortality after major amputation in patients with peripheral arterial disease remain unclear. We investigated the outcomes of major amputation in patients with peripheral arterial disease. Methods Patients who underwent major amputation from 2008 to 2015 were retrospectively analyzed. The main outcome measures were risk factors for wound complications and 30-day mortality after major lower limb amputations. Major amputation was defined as above-knee amputation or below-knee amputation. Wound complications were defined as surgical site infection or wound dehiscence. Results In total, 106 consecutive patients underwent major amputation. The average age was 77.3 ± 11.2 years, 67.9% of patients had diabetes mellitus and 35.8% were undergoing hemodialysis. Patients who underwent primary amputation constituted 61.9% of the cohort, and the proportions of above-knee amputation and below-knee amputation were 66.9% and 33.1%, respectively. The wound complication rate was 13.3% overall, 10.3% in above-knee amputation, and 19.5% in below-knee amputation. Multivariate analysis showed that the risk factors for wound complications were female sex (hazard ratio, 4.66; 95% confidence interval, 1.40-17.3; P = 0.01) and below-knee amputation (hazard ratio, 4.36; 95% confidence interval, 1.20-17.6; P = 0.03). The 30-day mortality rate was 7.6%, pneumonia comprised the most frequent cause of 30-day mortality, followed by sepsis and cardiac death. Multivariate analysis showed that a low serum albumin concentration (hazard ratio, 3.87; 95% confidence interval, 1.12-16.3; P = 0.03) was a risk factor for 30-day mortality. Conclusions Female sex and below-knee amputation were risk factors for wound complications. A low serum albumin concentration was a risk factor for 30-day mortality after major amputation in Japanese patients with peripheral arterial disease.

Prognostic factor of the two-year mortality after revascularization in patients with critical limb ischemia

Purposes

The aim of this study was to evaluate the risk factors for the two-year survival after revascularization of critical limb ischemia.

Methods

Between 2008 and 2012, 142 patients underwent revascularization. A retrospective analysis was performed to measure the risk factor.

Results

A total 85 patients underwent surgical revascularization, 31 patients underwent endovascular therapy while 26 patients underwent hybrid therapy. By multivariate analysis, the following variables were considered to be risk factors: ejection fraction <50 % (HR, 3.14; 95% CI, 1.22–7.95; P = 0.02), serum albumin level <2.5 g/dL (HR, 3.45; 95% CI, 1.01–11.7; P = 0.04) and nonambulatory status (HR, 4.11; 95% CI, 1.79–9.70; P < 0.01). The two-year survival rate of the patients with no risk factors was 85.5%, while the patients with at least one risk factor had an unfavorable prognosis (one; 56.7%, two; 45.4%).

Conclusions

The nonambulatory status, serum albumin level <2.5 g/dL and ejection fraction <50% were the risk factors for the two-year mortality after revascularization in critical limb ischemia patients. These risk factors may be useful for the treatment strategy of critical limb ischemia patients.

Results of isolated infrapopliteal percutaneous transluminal angioplasty for critical limb ischemia in high-risk diabetic patients

AIM

Infrapopliteal occlusive arterial lesions mostly characterize diabetic patients arteriopathy. Diabetic patients are prone to multiple comorbidities that make them candidates for low-invasive therapeutic options. The aim of this study was to evaluate the safety of infrapopliteal angioplasty in high-risk diabetic patients.

METHODS

We undertook a study (retrospective study of a prospectively collected database) of all infrapopliteal endovascular revascularizations performed for critical limb ischemia in high-risk (≥3 major comorbidities) diabetic patients in our institution between 2008 and 2010. Study end points were safety, technical success rate, healing rate, overall 1-year survival, primary patency, secondary patency and limb salvage rates.

RESULTS

A total of 101 high-risk diabetic patients (160 arterial lesions: 94 stenosis and 66 occlusions) underwent infrapopliteal endovascular surgery. No major adverse cardiovascular or cerebrovascular event was recorded within 30 days. Two major adverse limb events (two thromboses requiring major amputation) and seven minor adverse events were recorded. Technical and healing rates were, respectively, 83% and 78%. The 1-year survival, primary patency, secondary patency and limb salvage rates were, respectively, 86%, 67%, 83% and 84%.

CONCLUSION

Infrapopliteal angioplasty can be considered as a safe and feasible option for high-risk diabetic patients with critical limb ischemia.

Long-term results of combined aortoiliac and infrainguinal arterial reconstruction for the treatment of critical limb ischemia

OBJECTIVE

This study was designed to investigate our long-term experience with combined iliac endovascular therapy (EVT) and infrainguinal bypass to treat critical limb ischemia (CLI) and compare outcomes to those of patients who underwent surgery for aortoiliac lesions.

MATERIALS AND METHODS

From April 2000 to June 2013, 57 patients (58 limbs) underwent an infrainguinal bypass combined with aortoiliac reconstruction to treat CLI. Eighteen limbs were treated by bypass alone and 8 limbs were treated by bypass with EVT for aortoiliac lesions (Bypass group). Thirty-two limbs were subjected to EVT alone for iliac lesions (EVT group).

RESULTS

Preoperative limb ischemia was more severe in the EVT group. There were no significant differences in major procedure-related complications (χ(2) test, P = 0.853), systemic complications (P = 0.853), and mortality (P = 0.916) between the 2 groups. The limb salvage rates were 92% at 1, 3, and 5 years in the Bypass group and 93% at 1, 3, and 5 years in the EVT group, with no significant difference observed between the groups (Kaplan-Meier, log-rank test, P = 0.616).

CONCLUSION

Infrainguinal surgical reconstruction combined with an iliac EVT is an acceptable strategy for managing patients with CLI.