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

Competing risk analysis to estimate amputation incidence and risk in lower-extremity peripheral artery disease

Background: Patients with peripheral artery disease face high amputation and mortality risk. When assessing vascular outcomes, consideration of mortality as a competing risk is not routine. We hypothesize standard time-to-event methods will overestimate major amputation risk in chronic limb-threatening ischemia (CLTI) and non-CLTI. Methods: Patients undergoing peripheral vascular intervention from 2017 to 2018 were abstracted from the Vascular Quality Initiative registry and stratified by mean age (⩾ 75 vs < 75 years). Mortality and amputation data were obtained from Medicare claims. The 2-year cumulative incidence function (CIF) and risk of major amputation from standard time-to-event analysis (1 - Kaplan-Meier and Cox regression) were compared with competing risk analysis (Aalen-Johansen and Fine-Gray model) in CLTI and non-CLTI. Results: A total of 7273 patients with CLTI and 5095 with non-CLTI were included. At 2-year follow up, 13.1% of patients underwent major amputation and 33.4% died without major amputation in the CLTI cohort; 1.3% and 10.7%, respectively, in the non-CLTI cohort. In CLTI, standard time-to-event analysis overestimated the 2-year CIF of major amputation by 20.5% and 13.7%, respectively, in patients ⩾ 75 and < 75 years old compared with competing risk analysis. The standard Cox regression overestimated adjusted 2-year major amputation risk in patients ⩾ 75 versus < 75 years old by 7.0%. In non-CLTI, the CIF was overestimated by 7.1% in patients ⩾ 75 years, and the adjusted risk was overestimated by 5.1% compared with competing risk analysis. Conclusions: Standard time-to-event analysis overestimates the incidence and risk of major amputation, especially in CLTI. Competing risk analyses are alternative approaches to estimate accurately amputation risk in vascular outcomes research.

Illness Trajectories After Revascularization in Patients With Peripheral Artery Disease: A Unified Approach to Understanding the Risk of Major Amputation and Death

BACKGROUND

The aim of this study was to investigate the illness trajectories of patients with peripheral artery disease (PAD) after revascularization and estimate the independent risks of major amputation and death (from any cause) and their interaction.

METHODS

Data from Hospital Episode Statistics Admitted Patient Care were used to identify patients (≥50 years of age) who underwent lower limb revascularization for PAD in England from April 2013 to March 2020. A Markov illness-death model was developed to describe patterns of survival after the initial lower limb revascularization, if and when patients experienced major amputation, and survival after amputation. The model was also used to investigate the association between patient characteristics and these illness trajectories. We also analyzed the relative contribution of deaths after amputation to overall mortality and how the risk of mortality after amputation was related to the time from the index revascularization to amputation.

RESULTS

The study analyzed 94 690 patients undergoing lower limb revascularization for PAD from 2013 to 2020. The majority were men (65.6%), and the median age was 72 years (interquartile range, 64-79). One-third (34.8%) of patients had nonelective revascularization, whereas others had elective procedures. For nonelective patients, the amputation rate was 15.2% (95% CI, 14.4-16.0) and 19.9% (19.0-20.8) at 1 and 5 years after revascularization, respectively. For elective patients, the corresponding amputation rate was 2.7% (95% CI, 2.4-3.1) and 5.3% (4.9-5.8). Overall, the risk of major amputation was higher among patients who were younger, had tissue loss, diabetes, greater frailty, nonelective revascularization, and more distal procedures. The mortality rate at 5 years after revascularization was 64.3% (95% CI, 63.2-65.5) for nonelective patients and 33.0% (32.0-34.1) for elective patients. After major amputation, patients were at an increased risk of mortality if they underwent major amputation within 6 months after the index revascularization.

CONCLUSIONS

The illness-death model provides an integrated framework to understand patient outcomes after lower limb revascularization for PAD. Although mortality increased with age, the study highlights patients <60 years of age were at increased risk of major amputation, particularly after nonelective revascularization.

Contraindications to use of neuraxial anesthesia for lower limb revascularization surgery in adults: a cross-sectional study

PURPOSE

Nonrandomized and some randomized data suggest neuraxial anesthesia may improve outcomes after lower limb revascularization surgery. Nevertheless, the prevalence of contraindications to neuraxial anesthesia in vascular surgery patients is unknown. We aimed to identify the prevalence of patients with contraindications to neuraxial anesthesia, and to derive and validate a case ascertainment algorithm identifying individuals likely to have contraindications.

METHODS

We conducted a historical cross-sectional study of open lower limb revascularization surgeries performed between 2019 and 2021 at The Ottawa Hospital. Medical records were reviewed for demographic data, admission, procedural characteristics, and presence of contraindications to neuraxial anesthesia. Case ascertainment algorithms to predict the presence of absolute contraindications to neuraxial anesthesia were derived and internally validated.

RESULTS

We identified 340 cases. General anesthesia was used in 219 (64.4%) cases, isolated neuraxial (spinal and/or epidural) in 106 (31.2%) cases, and general plus neuraxial in 15 (4.4%) cases. Seventy-eight (22.9%; 95% confidence interval [CI], 18.8 to 27.7) patients had absolute contraindications to neuraxial anesthesia, primarily because of anticoagulation or antiplatelet medication (89.4%); 21 (6.2%; 95% CI, 4.1 to 9.3) had relative contraindications, primarily long anticipated duration of surgery (16/21, 76.2%). We derived and validated three nested case-ascertainment algorithms. Using admission and procedure variables, discrimination was moderate with moderately explained variance, and calibration was inadequate for reliable use. Patient comorbidity and laboratory data did not improve algorithm performance.

CONCLUSION

Most patients undergoing lower limb revascularization surgery did not have absolute contraindications to neuraxial anesthesia. When present, contraindications typically related to anticoagulation. Admission, procedure, comorbidity, and laboratory data did not provide adequate accuracy to ascertain contraindication status.

Outcomes After Neuraxial or Regional Anaesthesia Instead of General Anaesthesia for Lower Limb Revascularisation Surgery: A Systematic Review and Meta-Analysis of Randomised and Non-Randomised Studies

OBJECTIVE

To determine whether receipt of neuraxial or regional anaesthesia instead of general anaesthesia for lower limb revascularisation surgery affects patient outcomes.

DATA SOURCES

MEDLINE, EMBASE, Evidence Based Medicine Reviews, and Google Scholar.

REVIEW METHODS

After protocol registration, the data sources were searched for randomised and non-randomised studies comparing neuraxial or regional anaesthesia with general anaesthesia for lower limb revascularisation surgery in adults. Two investigators independently selected articles, extracted data, and assessed risks of bias. Data were pooled using random effects models. GRADE was used to assess certainty in cumulative evidence.

RESULTS

From 10 755 citations identified, five randomised (n = 970) and 13 non-randomised (n = 96 800) studies were included. Use of neuraxial instead of general anaesthesia for lower limb revascularisation surgery was associated with no statistically significant reduction in short term (in hospital or 30 day) mortality in randomised studies (pooled odds ratio [OR] 0.77; 95% confidence interval [CI] 0.33 - 1.81; low certainty) and a statistically significant reduction in adjusted short term mortality in non-randomised studies (pooled OR 0.67; 95% CI 0.56 - 0.81; low certainty). Adults allocated to neuraxial anaesthesia in randomised studies had fewer pulmonary complications (pooled OR 0.35; 95% CI 0.16 - 0.76; low certainty). In non-randomised studies, neuraxial instead of general anaesthesia was associated with a lower adjusted odds of any morbidity (pooled OR 0.66; 95% CI 0.52 - 0.84), cardiac complications (pooled OR 0.68; 95% CI 0.58 - 0.79), pneumonia (pooled OR 0.81; 95% CI 0.64 - 1.02), prolonged mechanical ventilation (OR 0.09; 95% CI 0.002 - 0.55), and bypass graft thrombosis (OR 0.70; 95% CI 0.59 - 0.85), as well as a shorter operative duration (low certainty for all). Use of a nerve block instead of general anaesthesia was associated with a lower adjusted odds of delirium (OR 0.16; 95% CI 0.06 - 0.42) and a shorter operative duration (low certainty for both).

CONCLUSION

Randomised and non-randomised data suggest that neuraxial anaesthesia for lower limb revascularisation surgery reduces morbidity and possibly mortality. Until randomised trials with a low risk of bias become available, this study supports use of neuraxial anaesthesia for these procedures where appropriate.

Evaluation of the ICD-10 system in coding revascularisation procedures in patients with peripheral arterial disease in England: A retrospective cohort study using national administrative and clinical databases

BACKGROUND

Many studies evaluating care in hospitals in England use the Hospital Episode Statistics (HES) administrative database. The aim of this study was to explore whether the International Classification of Diseases 10th Revision (ICD-10) system used by HES supported the evaluation of care received by patients with peripheral arterial disease (PAD) who had revascularisation.

METHODS

This retrospective cohort study used records on patients who had revascularisation for PAD between 1st January 2017 and 31st December 2019 in England, collected prospectively in the National Vascular Registry (NVR) and linked to HES. Patients were excluded if their NVR record did not have a match in HES, due to lack of consent or different admission and procedure dates. Agreement between different presentations of PAD recorded in the NVR and the ICD-10 diagnostic codes recorded in HES was evaluated using the unweighted Kappa statistic and sensitivity and specificity. Agreement between the NVR and HES was also assessed for gender, age, comorbidities, mode of admission, and procedure type and side.

FINDINGS

In total, 20,603 patients who had 24,621 admissions were included in the study. Agreement between NVR and HES on patient gender (Kappa = 0.98), age (Kappa = 0.98), mode of admission (Kappa = 0.80), and procedure type and side (Kappa = 0.92 and 0.87, respectively) was excellent. When all diagnostic fields in HES were explored, substantial agreement was observed for chronic ischaemia with tissue loss (Kappa = 0.63), but it was lower for chronic ischaemia without tissue loss (Kappa = 0.32) and acute limb ischaemia (Kappa = 0.15). Agreement on comorbidities was mixed; excellent for diabetes (Kappa = 0.82), moderate for chronic lung disease (Kappa = 0.56), chronic kidney disease (Kappa = 0.56), and ischaemic heart disease (Kappa = 0.45) and fair for chronic heart failure (Kappa = 0.35).

INTERPRETATION

The diagnostic ICD-10 codes currently used in HES cannot accurately differentiate between stages of PAD. Therefore, studies using HES to examine patterns of care and outcomes for patients with PAD are likely to suffer from misclassification bias. Adopting an extended ICD-10 system or the ICD-11 version released to the World Health Organisation member states in 2022, may overcome this problem.

FUNDING

Healthcare Quality Improvement Partnership (HQIP).

Paclitaxel-coated balloons for femoropopliteal peripheral arterial disease: final five-year results of the IN.PACT Global Study

BACKGROUND

Numerous randomised controlled trials (RCTs) have demonstrated the superiority of paclitaxel drug-coated balloons (DCBs) over non-coated angioplasty balloons for treatment of femoropopliteal peripheral arterial disease (PAD). There is a paucity of clinical evidence in more complex patients who are often excluded from RCTs and long-term data up to 5 years are very limited in PAD revascularisation studies.

AIMS

This is a report of the 5-year outcomes from the prospective, single-arm, international IN.PACT Global Study. The IN.PACT Admiral DCB was evaluated for femoropopliteal atherosclerotic disease treatment in a real-world patient population.

METHODS

In total, 1,535 patients were enrolled at 64 international sites. The prespecified clinical cohort included 1,406 patients with claudication or rest pain. Patients were evaluated up to 5 years for the occurrence of adverse events and clinically driven target lesion revascularisations (CD-TLR).

RESULTS

The mean lesion length was 12.1±9.5 cm in 1,774 lesions, 18.0% had in-stent restenosis, 35.5% were total occlusions and 68.7% were calcified. Per independent clinical events committee adjudication, the Kaplan-Meier estimate of freedom from CD-TLR up to 5 years was 69.4%, and the restricted mean survival time to first CD-TLR was 1,470.1 days. Outcomes were similar for males and females; freedom from CD-TLR was 69.1% in females and 69.6% in males (p=0.602). The cumulative incidence of major adverse events for the clinical cohort was 45.9% and freedom from all-cause mortality with the vital status update was 78.9% up to 5 years.

CONCLUSIONS

The IN.PACT Admiral DCB demonstrated safe and durable outcomes in real-world participants with complex femoropopliteal disease.

CLINICALTRIALS

gov: NCT01609296.

An exploration of specialist clinicians' experiences and beliefs about inpatient amputee rehabilitation as a pathway option for adult primary amputees

PURPOSE

To explore specialist amputee physiotherapists' experiences and subsequent views about specialist inpatient rehabilitation (IPR) as a National Health Service (NHS) pathway option for adult primary amputees and their perceptions and beliefs about the effects of inpatient amputee rehabilitation.

MATERIALS AND METHODS

A qualitative study using a phenomenological approach. Semi-structured interviews were completed with seven physiotherapists experienced in working in both specialist amputee inpatient and outpatient rehabilitation settings. Interviews were audio-recorded and fully transcribed. Data were analysed using thematic analyses; inductive coding was completed; emerging themes are shown and a conceptual framework was developed. To promote rigour, this study was peer reviewed and coding was done by two people.

RESULTS

Clinicians believed inpatient amputee rehabilitation to be the preferred model of rehabilitation for the majority of adult primary amputees. A central theme of healthcare inequality within primary amputee rehabilitation provision emerged with four sub-themes: IPR, outpatient rehabilitation, barriers, the ideal world. Geographical variation was described in: type of rehabilitation provided, timescales of prosthetic rehabilitation provision, fitting a prosthesis with wounds, and the availability of community rehabilitation services.

CONCLUSIONS

Healthcare inequality is a central concern identified by clinicians who work within amputee rehabilitation in the UK. Clinicians interviewed believe NHS specialist amputee inpatient rehabilitation should be a more accessible pathway.Implications for rehabilitationClinicians believe healthcare inequality exists within primary amputee rehabilitation provision in the UK National Health Service (NHS).Geographical variation in type of care provision, fitting a prosthesis with wounds, timescales in prosthetic rehabilitation provision and community rehabilitation services were described.Clinicians believe inpatient amputee rehabilitation to be the preferred model of care for the majority of adult primary amputees and should be a more accessible pathway within the NHS.Inpatient rehabilitation facilities may be a way of compensating for amputee rehabilitation inequalities.

Younger patients with chronic limb threatening ischemia face more frequent amputations

INTRODUCTION

Amputations among younger patients with chronic limb threatening ischemia (CLTI) may carry higher personal and societal costs, but younger patients are often not included in CLTI research because of dataset limitations. We aimed to characterize and compare outcomes between younger (<65 years old) and older patients with CLTI.

METHODS

This retrospective cohort study identified patients with CLTI between July 1, 2014 and December 31, 2017 in the MarketScan commercial claims database, a proprietary set of claims for over 50 million patients with private insurance in the United States. The primary outcome was major adverse limb events (MALE); secondary outcomes included amputations, major adverse cardiovascular events, and statin prescription fills.

RESULTS

The study cohort included 64,663 people with CLTI, of whom 25,595 (39.6%) were <65 years old. Younger patients were more likely to have diabetes mellitus (54.1% versus 49.9%, P<.001) but less likely to have other comorbidities. A higher proportion of younger patients suffered MALE (31.7% versus 30.2%, P=.002), specifically amputation (11.5% versus 9.3%, P<.001). After adjustment, age <65 years old was associated with a 24% increased risk of amputation (HR_adj 1.24, 95%CI 1.18-1.32, P<.001) and a 10% increased risk of MALE (HR_adj 1.10, 95%CI 1.07-1.14, P<.001).

CONCLUSIONS

A significant proportion of commercially insured patients with CLTI are under the age of 65, and younger patients have worse limb-related outcomes. These findings highlight the importance of aggressively treating risk factors for atherosclerosis and intentionally including younger patients with CLTI in future analyses to better understand their disease patterns and outcomes.

Reducing Nontraumatic Lower-Extremity Amputations by 20% by 2030: Time to Get to Our Feet: A Policy Statement From the American Heart Association

Nontraumatic lower-extremity amputation is a devastating complication of peripheral artery disease (PAD) with a high mortality and medical expenditure. There are ≈150 000 nontraumatic leg amputations every year in the United States, and most cases occur in patients with diabetes. Among patients with diabetes, after an ≈40% decline between 2000 and 2009, the amputation rate increased by 50% from 2009 to 2015. A number of evidence-based diagnostic and therapeutic approaches for PAD can reduce amputation risk. However, their implementation and adherence are suboptimal. Some racial/ethnic groups have an elevated risk of PAD but less access to high-quality vascular care, leading to increased rates of amputation. To stop, and indeed reverse, the increasing trends of amputation, actionable policies that will reduce the incidence of critical limb ischemia and enhance delivery of optimal care are needed. This statement describes the impact of amputation on patients and society, summarizes medical approaches to identify PAD and prevent its progression, and proposes policy solutions to prevent limb amputation. Among the actions recommended are improving public awareness of PAD and greater use of effective PAD management strategies (eg, smoking cessation, use of statins, and foot monitoring/care in patients with diabetes). To facilitate the implementation of these recommendations, we propose several regulatory/legislative and organizational/institutional policies such as adoption of quality measures for PAD care; affordable prevention, diagnosis, and management; regulation of tobacco products; clinical decision support for PAD care; professional education; and dedicated funding opportunities to support PAD research. If these recommendations and proposed policies are implemented, we should be able to achieve the goal of reducing the rate of nontraumatic lower-extremity amputations by 20% by 2030.

Paclitaxel-Coated Zilver PTX Drug-Eluting Stent Treatment Does Not Result in Increased Long-Term All-Cause Mortality Compared to Uncoated Devices

Purpose

Patient-level data from two large studies of the Zilver PTX drug-eluting stent (DES) with long-term follow-up and concurrent non-drug comparator groups were analyzed to determine whether there was an increased mortality risk due to paclitaxel.

Methods

Data from the Zilver PTX randomized controlled trial (RCT) and Zilver PTX and bare metal stent (BMS) Japan post-market surveillance studies were analyzed. Five-year follow-up is complete in both DES studies; follow-up for the BMS study was limited to 3 years and is complete. Kaplan–Meier analyses assessed mortality. A Cox proportional hazards model identified significant factors related to mortality.

Results

In the RCT, there were 336 patients treated with the DES and 143 patients treated with percutaneous transluminal angioplasty (PTA) or BMS. In Japan, there were 904 DES patients and 190 BMS patients. There was no difference in all-cause mortality for the DES compared to PTA/BMS in the RCT (19.1% DES versus 17.1% PTA/BMS through 5 years, p = 0.60) or Japan (15.8% DES versus 15.3% BMS through 3 years, p = 0.89). Cox proportional hazard models revealed that age, tissue loss, and congestive heart failure were significantly associated with mortality in the RCT, and critical limb ischemia, age, renal failure, and gender were significantly associated with mortality in Japan (all p < 0.05). Neither treatment with Zilver PTX (p = 0.46 RCT, p = 0.49 Japan) nor paclitaxel dose (p = 0.86 RCT, p = 0.07 Japan) was associated with mortality.

Conclusion

Analyses of the Zilver PTX patient-level data demonstrated no increase in long-term all-cause mortality.

Level of Evidence

Zilver PTX RCT: Level 1, randomized controlled trial; Japan PMS studies: Level 3, post-market surveillance study.

Electronic supplementary material

The online version of this article (10.1007/s00270-019-02324-4) contains supplementary material, which is available to authorized users.