Epidemiological analysis of lower limb revascularization for peripheral arterial disease over 12 years on the public healthcare system in Brazil

Abstract Background Worldwide, peripheral arterial disease (PAD) is a disorder with high morbidity, affecting more than 200 million people. Objectives Our objective was to analyze surgical treatment for PAD provided on the Brazilian Public Healthcare System over 12 years using publicly available data. Methods The study was conducted with analysis of data available on the Brazilian Health Ministry’s database platform, assessing distributions of procedures and techniques over the years and their associated mortality and costs. Results A total of 129,424 procedures were analyzed (performed either for claudication or critical ischemia, proportion unknown). The vast majority of procedures were endovascular (65.49%) and this disproportion exhibited a rising trend (p<0.001). There were 3,306 in-hospital deaths (mortality of 2.55%), with lower mortality in the endovascular group (1.2% vs. 5.0%, p=0.008). The overall governmental expenditure on these procedures was U$ 238,010,096.51, and endovascular procedures were on average significantly more expensive than open surgery (U$ 1,932.27 vs. U$ 1,517.32; p=0.016). Conclusions Lower limb revascularizations were performed on the Brazilian Public Healthcare System with gradually increasing frequency from 2008 to 2019. Endovascular procedures were vastly more common and were associated with lower in-hospital mortality rates, but higher procedure costs.

Rates of intervention for claudication versus chronic limb-threatening ischemia in Canada and United States

BACKGROUND

Previous studies have demonstrated important geographic variations in peripheral artery disease (PAD) management despite existing guidelines. We assessed differences in patient characteristics, procedural technique, and outcomes for PAD interventions in Canada vs. United States.

METHODS

The Vascular Quality Initiative (VQI) was used to identify all patients who underwent endovascular intervention or surgical bypass for PAD between 2010-2019 in Canada and United States. Independent t-test and chi-square test were performed to assess differences between countries in terms of demographic, clinical, and procedural characteristics. The primary outcome was the percentage of interventions performed for claudication vs. chronic limb-threatening ischemia (CLTI). Perioperative outcomes were in-hospital mortality and index limb amputation. The long-term outcome was 1-year amputation-free survival. Univariate/multivariate logistic regression and Cox proportional hazards analysis were performed to investigate associations between region and outcomes.

RESULTS

246,770 US patients and 3,467 Canadian patients underwent revascularization for PAD during the study period. There was a higher proportion of endovascular interventions in the US (75.9% vs. 69.2%, OR 1.41 [95% CI 1.31 - 1.51], p < 0.001). American patients were younger with more comorbidities, including hypertension, diabetes, and coronary artery disease. The percentage of interventions performed for claudication was significantly higher in the US (42.3% vs. 35.7%, OR 1.31 [95% CI 1.22 - 1.44], p < 0.001). This persisted after controlling for demographic, clinical, and procedural characteristics (adjusted OR 1.05 [95% CI 1.01 - 1.10], p = 0.02). Perioperative outcomes were similar between countries after adjustment for baseline differences: in-hospital mortality (adjusted OR 1.07 [95% CI 0.69 - 1.62], p = 0.75) and index limb amputation (adjusted OR 0.67 [95% CI 0.43 - 1.07], p = 0.09). However, 1-year amputation-free survival was higher in the US (84.1% vs. 71.0%, HR 1.61 [95% CI 1.47 - 1.76], p < 0.001). Multivariable Cox proportional hazards analysis demonstrated that the factor most strongly associated with index limb amputation or death at 1-year was intervention for CLTI (HR 1.56 [95% CI 1.54 - 1.58], p < 0.001).

CONCLUSIONS

There are significant variations in PAD management between US and Canada. In particular, a higher proportion of interventions are performed for claudication rather than CLTI in the US compared to Canada. This is an important contributor to the higher 1-year amputation-free survival rate in US patients. Reasons for these differences should be assessed by future studies and evidence-based care may be standardized by targeted quality improvement projects.

Adverse Prognosis of Peripheral Artery Disease Treatments Associated With Diabetes: A Comprehensive Meta-Analysis

Many studies have investigated the influence of diabetes mellitus (DM) on outcomes in patients with peripheral artery disease (PAD). We performed a meta-analysis of the outcomes of PAD treatments in DM patients compared with those without DM. Long-term mortality was the primary endpoint. Secondary endpoints were in-hospital/30-day mortality, primary/secondary patency, amputation, and limb salvage. Thirty-one studies reporting 58113 patients were eligible for enrollment. The mean follow-up duration ranged from 1 to 89 months. DM was significantly associated with long-term mortality (relative risk (RR) = 1.67; 95% confidence intervals (CI), 1.43-1.94; P < .001). DM was also associated with significantly lower primary patency (RR = 0.74; 95% CI, 0.58-0.95; P = .001) and secondary patency (RR = 0.80; 95% CI, 0.67-0.96; P = .009). DM is associated with worse outcomes and adverse prognosis of treatment in patients with PAD, and may therefore be a modifiable risk factor for poor prognosis in PAD patients.

Popliteal Artery Angioplasty for Chronic Total Occlusions with versus without the Distal Landing Zone

BACKGROUND

The purpose of this study was to evaluate the outcome of percutaneous transluminal angioplasty in patients with critical limb ischemia due to popliteal artery (PA) chronic total occlusions depending on the presence of a patent portion of the PA distal to the occlusive lesion-the distal landing zone (DLZ).

MATERIALS AND METHODS

We retrospectively analyzed 80 patients with critical limb ischemia (all Rutherford class 5-6), who underwent percutaneous transluminal angioplasty with or without stenting for PA chronic total occlusions with no inflow disease. Baseline demographic and clinical variables, periprocedural outcome, 12-month overall survival, limb salvage, primary patency, freedom from target lesion revascularization (TLR), amputation-free survival, and freedom from major adverse limb events in DLZ versus no-DLZ lesions were assessed.

RESULTS

Of all patients (43 men; mean age 70.2 y), 40 (50%) had DLZ in the PA, whereas another 40 (50%) did not (no-DLZ). Diabetes was significantly more common among DLZ patients and was found to be a risk factor for DLZ compared with no-DLZ lesions (HR 2.58; 95% CI 1.03-6.46; P = 0.04). Other demographic and clinical variables were similar between the groups. The stenting rate was 45.0% versus 42.5% in DLZ versus no-DLZ (P = 1.0). At 12 months, there was no significant difference in primary patency (64.7% vs. 51.6%; P = 0.156), overall survival (73.4% vs. 84.0%; P = 0.283), amputation-free survival (60.0% vs. 68.8%; P = 0.432), and limb salvage rate (93.6% vs. 82.2%; P = 0.126) between DLZ and no-DLZ groups, respectively. However, freedom from TLR (92.1% vs. 67.7%; P = 0.03) and major adverse limb events (80.1% vs. 41.8%; P = 0.003) was significantly higher in DLZ compared with no-DLZ lesions (92.1% vs. 67.7%; P = 0.03).

CONCLUSIONS

Diabetes was found to be a significant risk factor for DLZ compared to no-DLZ lesions. Technical success and stenting rates were similar in DLZ versus no-DLZ patients. At 12 months, there was no significant difference in limb salvage, primary patency, and overall survival between the study groups. The DLZ lesions were associated with a significantly higher freedom from TLR than no-DLZ lesions.

Changes in rates of vascular procedure types and lower extremity amputations in Finland for 2007-2017 inclusive, a population cohort study of 69,523 revascularizations

INTRODUCTION

Since 2000 the numbers of both open and endovascular revascularization procedures have increased. Despite these increases, the number of major lower extremity amputations (LEAs) has remained relatively constant. The aim of the present study was to assess the number of vascular procedures in relation to the frequency of major LEAs in Finland.

METHODS

The Finnish National Institute for Health and Welfare (THL) administers a national registry of all procedures conducted by official healthcare providers in Finland. Data regarding all revascularization procedures and major LEAs between 2007 and 2017 inclusive, were collected from the THL registry. The rates of both open and endovascular procedures were analyzed.

RESULTS

A total of 69,523 revascularization procedures were registered over the 11-year period. Of all revascularizations, 22.6% were endovascular in 2007, which rose to 60.5% in 2017. The annual rates of vascular procedures per 100,000 inhabitants increased from 66 in 2007 to 172 in 2017 (increase 10 procedures per year, 95% CI 8.6-12.3, P < 0.01) There was a significant increase (by 141 per year, 95% CI 110-174, P < 0.01) for open revascularizations (2705 operations in 2007, 3992 operations in 2017) and (by 491 per year, 95% CI 433-550, P < 0.01) for endovascular revascularizations (791 in 2007-5514 in 2017). Open aorto-iliac segment revascularization decreased, whereas the numbers of procedures increased for all other arterial segments. The overall frequency of amputations was 18-20 per 100,000. The frequency of amputations in the subpopulation over 65 years old decreased from 93 in 2007 to 72 in 2017 (P < 0.01).

CONCLUSION

The present study demonstrated increases in vascular surgery procedures over the 11-year study-period. The increase was greatest for endovascular procedures. During the same period, there was a significant decrease in the frequency of major LEAs in the >65-year-old subpopulation.

Population-based study of mortality and major amputation following lower limb revascularization

Background

The aim of this study was to estimate separate risks of major lower limb amputation and death following revascularization for peripheral artery disease (PAD) using competing risks analysis.

Methods

Routinely collected data from Hospital Episode Statistics (HES) were used to identify patients who underwent endovascular or open lower limb revascularization for PAD in England from 2005 to 2015. The primary outcomes were major lower limb amputation and death within 5 years of revascularization. Cox proportional hazards and Fine–Gray competing risks regression were used to examine the competing risks of these outcomes.

Results

Some 164 845 patients underwent their first lower limb revascularization for PAD during the study interval. Most were men (64·6 per cent) and the median age was 71 (i.q.r. 62–78) years. Following endovascular revascularization, the 5-year cumulative incidence of amputation was 4·2 per cent in patients with intermittent claudication and 18·0 per cent in those with a record of tissue loss. The corresponding rates were 10·8 and 25·3 per cent respectively after open revascularization, and 8·1 and 25·0 per cent after combined procedures. The 5-year cumulative incidence of death varied from 24·5 to 39·8 per cent, depending on procedure type. Competing risks methods consistently produced lower estimates than standard methods.

Conclusion

The 5-year risk of major amputation following lower limb revascularization for PAD appears lower than estimated previously. Patients undergoing revascularization for tissue loss and those who require an open procedure are at highest risk of limb loss.

Long-Term Clinical Outcomes of Infrapopliteal Drug-Eluting Stent Placement for Critical Limb Ischemia in Diabetic Patients

PURPOSE

To evaluate long-term clinical outcomes of infrapopliteal drug-eluting stent (DES) placement in insulin-dependent and non-insulin-dependent diabetic patients with critical limb ischemia (CLI).

MATERIALS AND METHODS

A retrospective analysis was performed of all diabetic patients treated with infrapopliteal DES between January 2002 and September 2012. The study's primary outcome measures were patient survival and major amputation-free survival (AFS). Secondary outcome measures included technical success (defined as the creation of a straight line of blood flow to the foot arch with < 30%), identification of independent predictors of primary outcomes, infrapopliteal target limb repeat intervention-free survival, and procedure-related complications.

RESULTS

In total, 214 patients with CLI (168 men [78.5%]; mean age, 70 y ± 9) in 311 limbs, 562 arteries, and 679 lesions were treated. According to Kaplan-Meier analysis, survival rates were 90.8%, 55.5%, and 36.2%, and AFS rates were 94.9%, 90.4%, and 90.4%, respectively, at 1, 5, and 10 years. Target limb repeat intervention-free survival rates were 79.7%, 55.2%, and 49.7%, respectively, at 1, 5, and 10 years. The overall technical success rate was 97.7%. Cox multivariate analysis demonstrated that procedural failure was the only independent predictor of decreased AFS (hazard ratio [HR], 61.3; 95% confidence interval [CI], 13.8-271.9), and statin use was associated with increased survival (HR, 0.55; 95% CI, 0.31-0.98). Coronary disease (HR, 1.9; 95% CI, 1.01-3.54), dialysis (HR, 2.2; 95% CI, 1.21-4.06), and duration of diabetes (HR, 1.5; 95% CI, 1.02-2.34) were identified as independent predictors of decreased survival. Major complications occurred in four of 479 procedures (0.8%).

CONCLUSIONS

Infrapopliteal DES placement for the management of CLI in diabetic patients resulted in a 55.5% 5-year survival rate, with a 90.4% AFS at 5 and 10 years and a 50.3% repeat intervention rate at 10 years. Technical failure was associated with reduced AFS, and statin intake was associated with increased survival.

Peripheral arterial disease and revascularization of the diabetic foot

Diabetes is a complex disease with many serious potential sequelae, including large vessel arterial disease and microvascular dysfunction. Peripheral arterial disease is a common large vessel complication of diabetes, implicated in the development of tissue loss in up to half of patients with diabetic foot ulceration. In addition to peripheral arterial disease, functional changes in the microcirculation also contribute to the development of a diabetic foot ulcer, along with other factors such as infection, oedema and abnormal biomechanical loading. Peripheral arterial disease typically affects the distal vessels, resulting in multi-level occlusions and diffuse disease, which often necessitates challenging distal revascularisation surgery or angioplasty in order to improve blood flow. However, technically successful revascularisation does not always result in wound healing. The confounding effects of microvascular dysfunction must be recognised--treatment of a patient with a diabetic foot ulcer and peripheral arterial disease should address this complex interplay of pathophysiological changes. In the case of non-revascularisable peripheral arterial disease or poor response to conventional treatment, alternative approaches such as cell-based treatment, hyperbaric oxygen therapy and the use of vasodilators may appear attractive, however more robust evidence is required to justify these novel approaches.

Identifying complications of interventional procedures from UK routine healthcare databases: a systematic search for methods using clinical codes

BACKGROUND

Several authors have developed and applied methods to routine data sets to identify the nature and rate of complications following interventional procedures. But, to date, there has been no systematic search for such methods. The objective of this article was to find, classify and appraise published methods, based on analysis of clinical codes, which used routine healthcare databases in a United Kingdom setting to identify complications resulting from interventional procedures.

METHODS

A literature search strategy was developed to identify published studies that referred, in the title or abstract, to the name or acronym of a known routine healthcare database and to complications from procedures or devices. The following data sources were searched in February and March 2013: Cochrane Methods Register, Conference Proceedings Citation Index - Science, Econlit, EMBASE, Health Management Information Consortium, Health Technology Assessment database, MathSciNet, MEDLINE, MEDLINE in-process, OAIster, OpenGrey, Science Citation Index Expanded and ScienceDirect. Of the eligible papers, those which reported methods using clinical coding were classified and summarised in tabular form using the following headings: routine healthcare database; medical speciality; method for identifying complications; length of follow-up; method of recording comorbidity. The benefits and limitations of each approach were assessed.

RESULTS

From 3688 papers identified from the literature search, 44 reported the use of clinical codes to identify complications, from which four distinct methods were identified: 1) searching the index admission for specified clinical codes, 2) searching a sequence of admissions for specified clinical codes, 3) searching for specified clinical codes for complications from procedures and devices within the International Classification of Diseases 10th revision (ICD-10) coding scheme which is the methodology recommended by NHS Classification Service, and 4) conducting manual clinical review of diagnostic and procedure codes.

CONCLUSIONS

The four distinct methods identifying complication from codified data offer great potential in generating new evidence on the quality and safety of new procedures using routine data. However the most robust method, using the methodology recommended by the NHS Classification Service, was the least frequently used, highlighting that much valuable observational data is being ignored.

Multimodal intraoperative monitoring: an observational case series in high risk patients undergoing major peripheral vascular surgery

Recent guidelines from the National Institute of Health and Care Excellence (NICE) and the UK National Health Service (NHS) have stipulated that intraoperative flow monitoring should be used in high-risk patients undergoing major surgery to improve outcomes and reduce costs. Depth of anaesthesia monitoring is also recommended for patients where excessive anaesthetic depth is poorly tolerated, along with cerebral oximetry in patients with proximal femoral fractures. The aims of this descriptive case series were to evaluate the impact of a multimodal intraoperative strategy and its effect on mortality and amputation rate for patients with critical leg ischaemia. In an observational case series, 120 elderly patients undergoing major infra-inguinal bypass between 2007 and 2012 were included in this retrospective analysis of prospectively collected data. Nominal cardiac output (nCO, LiDCOrapid, LiDCO Ltd, UK), bispectral index to monitor depth of anaesthesia (BIS, Covidien, USA) and cerebral oxygenation, rSO2 (Invos, Covidien, USA) readings were obtained before induction of general anaesthesia and throughout surgery. 30 day, 1-year mortality and amputation rates were analysed. Demographics and physiological parameters including correlation with V-POSSUM, age, gender and other co-morbidities were statistically analysed. Thirty-day mortality rate was 0.8% (n = 1). V-POSSUM scoring indicated a predicted mortality of 9%. Amputation rate was less than 2% at one year. Only 8% of patients (10 of 120) were admitted to a high dependency unit (HDU) postoperatively. 30-day mortality in our case series was lower than predicted by V-POSSUM scoring. Use of multimodal intraoperative monitoring with the specific aim of limiting build-up of oxygen debt should be subjected to a randomised controlled study to assess the reproducibility of these results.

Trends in 1-year survival of people admitted to hospital in Ontario, 1994-2009

BACKGROUND

Changes in the long-term survival of people admitted to hospital is unknown. This study examined trends in 1-year survival of patients admitted to hospital adjusted for improved survival in the general population.

METHODS

One-year survival after admission to hospital was determined for all adults admitted to hospital in Ontario in 1994, 1999, 2004, or 2009 by linking to vital statistics datasets. Annual survival in the general population was determined from life tables for Ontario.

RESULTS

Between 1994 and 2009, hospital use decreased (from 8.8% to 6.3% of the general adult population per year), whereas crude 1-year mortality among people with hospital admissions increased (from 9.2% to 11.6%). During this time, patients in hospital became significantly older (median age increased from 51 to 58 yr) and sicker (the proportion with a Charlson comorbidity index score of 0 decreased from 68.2% to 60.0%), and were more acutely ill on admission (elective admissions decreased from 47.4% to 42.0%; proportion brought to hospital by ambulance increased from 16.1% to 24.8%). Compared with 1994, the adjusted odds ratio (OR) for death at 1 year in 2009 was 0.78 (95% confidence interval [CI] 0.77-0.79). However, 1-year risk of death in the general population decreased by 24% during the same time. After adjusting for improved survival in the general population, risk of death at 1 year for people admitted to hospital remained significantly lower in 2009 than in 1994 (adjusted relative excess risk 0.81, 95% CI 0.80-0.82).

INTERPRETATION

After accounting for both the increased burden of patient sickness and improved survival in the general population, 1-year survival for people admitted to hospital increased significantly from 1994 to 2009. The reasons for this improvement cannot be determined from these data.

Peripheral arterial disease and bypass surgery in the diabetic lower limb

PAD is very common in people with diabetes and is one of the strongest predictors of developing nonhealing foot ulcers and suffering amputation. There is strong evidence to show that early detection of PAD and revascularization will reduce amputations. Despite this, many patients have no vascular assessment even when they present with a foot ulcer or before amputation. Even when identified, patients are referred late, which worsens their outcome. Currently there is no evidence to support surgical revascularization over endovascular treatments, but in reality the techniques are complementary and the choice of revascularization procedure should be determined by an experienced multidisciplinary vascular team. Surgical revascularization can achieve good results but careful patient selection, operative planning, and the use of autologous vein are necessary. What is clearly apparent is that at present not enough patients are being offered revascularization to prevent amputation.

Systematic review and meta-analysis of vein cuffs for below-knee synthetic bypass

BACKGROUND

The aim was to investigate the possible benefit of vein cuffs for femoral to below-knee popliteal and femorodistal vessel synthetic bypass grafts.

METHODS

PubMed, the Cochrane library, Embase and ClinicalTrials.gov were searched for all studies on any clinical effect of vein cuffs on synthetic grafts. Outcomes were selected based on inclusion in two or more studies: primary patency and limb survival. The data were subjected to meta-analysis by outcome.

RESULTS

Three cohort and two randomized studies were selected for inclusion, involving 885 patients. Meta-analysis of five studies examining below-knee popliteal bypass showed a significant improvement for primary patency in cuffed grafts at 2 years, but not at 1 or 3 years (odds ratio at 2 years 0·46, 95 per cent confidence interval 0·22 to 0·97; P = 0·04). Limb salvage was significantly improved in cuffed grafts up to 2 years. Limb survival was also improved for cuffed distal grafts at 2 years (odds ratio 0·29, 0·11 to 0·75; P = 0·01) but showed no difference at any other time interval. Study quality was generally poor, with conflicting results.

CONCLUSION

There was a small but significant benefit for vein cuffs on synthetic grafts used for femoral to below-knee popliteal anastomoses, but little benefit for femorodistal anastomoses.

A cellular delivery system fabricated with autologous BMSCs and collagen scaffold enhances angiogenesis and perfusion in ischemic hind limb

Although therapeutic cellular angiogenesis is effective for chronic ischemia, the optimal mode of cellular administration is still under exploration. This study aimed to develop a cellular delivery system to enhance the perfusion and angiogenesis in the ischemic hind limb. Collagen scaffold (CS) was prepared, and for morphology and toxicity analysis, bone marrow-derived mesenchymal stem cells (BMSCs) were isolated, expanded, filtrated, and seeded onto CS to construct BMSCs-CS. The ischemic hind limbs of rabbit models were implanted with autologous BMSCs-CS, CS, and autologous BMSCs; the untreated ischemic or normal animals were considered as the ischemic or normal control groups. Oxygen saturation parameters were regularly measured to determine the perfusion in the extremities. Histological examinations with hematoxylin and eosin immunostaining against von Willebrand factor and smooth muscle (SM) α-actin were performed for capillary and mature vessel evaluation. CS was a multiporous structure without cytotoxicity. At several intervals, the oxygen saturation ratio (OSR) in normal control was the highest. The OSRs in BMSCs-CS and CS were higher than that in BMSCs and ischemic control (p < 0.05); the OSR in BMSCs-CS group was higher than that in CS at 6 and 8 weeks (p < 0.05). The capillaries in BMSCs-CS and CS were higher than that in CS, BMSCs, and the ischemic or normal control (p < 0.05). The mature vessels in BMSCs-CS were higher than that in CS, BMSCs, and the ischemic or normal control (p < 0.05). The autologous cellular delivery system proved to be an effective approach for improving higher ischemic hind limb perfusion and angiogenesis as opposed to cellular therapy alone.