Graeme K. Ambler

Effect of frailty on short‐ and mid‐term outcomes in vascular surgical patients

Frailty is a multidimensional vulnerability resulting from age‐associated decline. The impact of frailty on outcomes was assessed in a cohort of vascular surgical patients.

Incidence and Outcomes of Severe Renal Impairment Following Ruptured Abdominal Aortic Aneurysm Repair.

INTRODUCTION Acute kidney injury (AKI) following ruptured abdominal aortic aneurysm (rAAA) repair is common and multifactorial. A standard definition of AKI after endovascular repair (EVAR), the Aneurysm Renal Injury Score (ARISe), has been proposed to facilitate standardised reporting and thus improve understanding of this issue. METHODS Data were collected retrospectively on AKI in a prospectively maintained database of all patients treated for rAAA in a single tertiary referral centre since the availability of routine out of hours emergency EVAR. The ARISe score was used to describe the degree of AKI and factors which correlated with poor renal outcomes were assessed. RESULTS Two-hundred and five patients were treated between January 2006 and April 2014. Of these, 125 were treated with open repair (OSR) and 80 were treated with EVAR. Severe AKI (defined as ARISe score ≥3) occurred in 36% of patients. After correction for confounders, patients treated with OSR were significantly more likely to develop severe AKI (43% vs. 26%, p = .02). There was no significant difference in preoperative serum creatinine between groups, but increased preoperative serum creatinine was strongly associated with severe AKI postoperatively (p < .001). Age, sex, endograft type, and preoperative CT scanning were not associated with differences in renal outcomes. Clamp position above renal arteries was predictive of severe AKI in patients treated with OSR (p < .01). Patients suffering severe AKI had significantly higher mortality at 30 days and 12 months (28% vs. 5% and 44% vs. 13%, p < .001 for both comparisons). CONCLUSION Severe AKI is common following successful repair of rAAA. In this large case series of high-risk patients, OSR was associated with significantly higher rates of severe AKI compared with EVAR, despite the increased dose of contrast involved in EVAR and the older age of these patients. In turn, severe AKI was associated with higher mortality rates.

The Abdominal Aortic Aneurysm Statistically Corrected Operative Risk Evaluation (AAA SCORE) for predicting mortality after open and endovascular interventions

BACKGROUND Accurate adjustment of surgical outcome data for risk is vital in an era of surgeon-level reporting. Current risk prediction models for abdominal aortic aneurysm (AAA) repair are suboptimal. We aimed to develop a reliable risk model for in-hospital mortality after intervention for AAA, using rigorous contemporary statistical techniques to handle missing data. METHODS Using data collected during a 15-month period in the United Kingdom National Vascular Database, we applied multiple imputation methodology together with stepwise model selection to generate preoperative and perioperative models of in-hospital mortality after AAA repair, using two thirds of the available data. Model performance was then assessed on the remaining third of the data by receiver operating characteristic curve analysis and compared with existing risk prediction models. Model calibration was assessed by Hosmer-Lemeshow analysis. RESULTS A total of 8088 AAA repair operations were recorded in the National Vascular Database during the study period, of which 5870 (72.6%) were elective procedures. Both preoperative and perioperative models showed excellent discrimination, with areas under the receiver operating characteristic curve of .89 and .92, respectively. This was significantly better than any of the existing models (area under the receiver operating characteristic curve for best comparator model, .84 and .88; P < .001 and P = .001, respectively). Discrimination remained excellent when only elective procedures were considered. There was no evidence of miscalibration by Hosmer-Lemeshow analysis. CONCLUSIONS We have developed accurate models to assess risk of in-hospital mortality after AAA repair. These models were carefully developed with rigorous statistical methodology and significantly outperform existing methods for both elective cases and overall AAA mortality. These models will be invaluable for both preoperative patient counseling and accurate risk adjustment of published outcome data.

Mid‐term cost‐effectiveness analysis of open and endovascular repair for ruptured abdominal aortic aneurysm

Emergency endovascular repair (EVAR) for ruptured abdominal aortic aneurysm (rAAA) may have lower operative mortality rates than open surgical repair. Concerns remain that the early survival benefit after EVAR for rAAA may be offset by late reinterventions. The aim of this study was to compare reintervention rates and cost‐effectiveness of EVAR and open repair for rAAA.

Premorbid function, comorbidity, and frailty predict outcomes after ruptured abdominal aortic aneurysm repair.

OBJECTIVE Strategies to improve outcomes for patients with ruptured abdominal aortic aneurysm (rAAA) are becoming more evident. The aging population, however, continues to make the decision to intervene often difficult, especially given that traditional risk models do not reflect issues of aging and frailty. This study aimed to integrate measures of function alongside comorbidity- and frailty-specific factors to determine outcome. METHODS Patients treated for a rAAA between January 2006 and April 2014 were assessed. Demographics, mortality, and requirement for care after discharge as well as a variety of measures of function (physical, social, and psychological) and comorbidity were recorded. The primary outcome was 1-year mortality. Outcome models were generated using multivariate logistic regression and were compared with models of vascular frailty and AAA-related outcome. RESULTS Of 184 patients treated, 108 (59%) underwent an open surgical repair. The overall 30-day and 1-year mortality were 21.5% and 31.4%, respectively, with an overall median hospital length of stay of 13 days (interquartile range, 6-27 days). An optimal logistic regression model for 12-month mortality used Katz score, Charlson score, number of admission medicines, visual impairment, hearing impairment, hemoglobin level, and statin use as predictors, achieving an area under the receiver operating characteristic curve of 0.84. CONCLUSIONS This novel rAAA model incorporating function and comorbidity offers good predictive power for mortality. It is quick to calculate and may ultimately become helpful for both counseling and selection of patients and comparative audit at a time when outcome in patients with rAAA increasingly comes under the spotlight.

Independence and mobility after infrainguinal lower limb bypass surgery for critical limb ischemia.

BACKGROUND Critical limb ischemia (CLI) is a common condition associated with high levels of morbidity and mortality. Most work to date has focused on surgeon-oriented outcomes such as patency, but there is increasing interest in patient-oriented outcomes such as mobility and independence. OBJECTIVE This study was conducted to determine the effect of infrainguinal lower limb bypass surgery (LLBS) on postoperative mobility in a United Kingdom tertiary vascular surgery unit and to investigate causes and consequences of poor postoperative mobility. METHODS We collected data on all patients undergoing LLBS for CLI at our institution during a 3-year period and analyzed potential factors that correlated with poor postoperative mobility. RESULTS During the study period, 93 index LLBS procedures were performed for patients with CLI. Median length of stay was 11 days (interquartile range, 11 days). The 12-month rates of graft patency, major amputation, and mortality were 75%, 9%, and 6%, respectively. Rates of dependence increased fourfold during the first postoperative year, from 5% preoperatively to 21% at 12 months. Predictors of poor postoperative mobility were female sex (P = .04) and poor postoperative mobility (P < .001), initially and at the 12-month follow-up. Patients with poor postoperative mobility had significantly prolonged hospital length of stay (15 vs 8 days; P < .001). CONCLUSIONS Patients undergoing LLBS for CLI suffer significantly impaired postoperative mobility, and this is associated with prolonged hospital stay, irrespective of successful revascularization. Further work is needed to better predict patients who will benefit from revascularization and in whom a nonoperative strategy is optimal.

Infrapopliteal angioplasty using a combined angiosomal reperfusion strategy

Introduction Infra-popliteal angioplasty continues to be widely performed with minimal evidence to guide practice. Endovascular device selection is contentious and there is even uncertainty over which artery to treat for optimum reperfusion. Direct reperfusion (DR) targets the artery supplying the ischaemic tissue. Indirect reperfusion (IR) targets an artery supplying collaterals to the ischaemic area. Our unit practice for the last eight years has been to attempt to open all tibial arteries at the time of angioplasty. When successful, this results in both direct and indirect; or combined reperfusion (CR). The aim was to review the outcomes of CR and compare them with DR or IR alone. Methods An eight year retrospective review from a single unit of all infra-popliteal angioplasties was undertaken. Wound healing, limb salvage, amputation-free and overall survival data as well as re-intervention rates were captured for all patients. Subgroup analysis for diabetics was undertaken. Kaplan Meier curves are presented for survival outcomes. All odds and hazard ratios (HR) and p values were corrected for bias from confounders using multivariate analysis. Results 250 procedures were performed: 22 (9%) were CR; 115 (46%) DR and 113 (45%) IR. Amputation-free survival (HR 0.504, p = 0.039) and re-intervention and amputation-free survival (HR 0.414, p = 0.005) were significantly improved in patients undergoing CR compared to IR. Wound healing was similarly affected by reperfusion strategy (OR = 0.35, p = 0.047). Effects of CR over IR were similar when only diabetic patients were considered. Conclusions Combined revascularisation can only be achieved in approximately 10% of patients. However, when successful, it results in significant improvements in wound healing and amputation-free survival over simple indirect reperfusion techniques.

Development of a core outcome set for studies involving patients undergoing major lower limb amputation for peripheral arterial disease: study protocol for a systematic review and identification of a core outcome set using a Delphi survey

BackgroundThe development of a standardised reporting set is important to ensure that research is directed towards the most important outcomes and that data is comparable. To ensure validity, the set must be agreed by a consensus of stakeholders including patients, healthcare professionals and lay representatives. There is currently no agreed core outcome set for patients undergoing major lower limb amputation for peripheral arterial disease (PAD) for either short- or medium-term research outcomes. By developing these sets we aim to rationalise future trial outcomes, facilitate meta-analysis and improve the quality and applicability of amputation research.Methods/designWe will undertake a comprehensive systematic review of studies of patients undergoing major lower limb amputation for PAD. Data regarding all primary and secondary outcomes reported in relevant studies will be extracted and summarised as outcome domains. We will then undertake focus groups with key stakeholders (patients, carers, health and social care workers) to collect qualitative data to identify the main short- and medium-term research outcomes for patients undergoing major lower limb amputation. Results of the systematic review and focus groups will be combined to create a comprehensive list of potential key outcomes. Stakeholders (patients, researchers and health and social care workers) will then be polled to determine which of the outcomes are considered to be important in a general context using a three-phase Delphi process. After preliminary analysis, results will be presented at a face-to-face meeting of key stakeholders for discussion and voting on the final set of core outcomes. This project is being run in parallel with a feasibility trial assessing perineural catheters in patients undergoing lower limb amputation (the PLACEMENT trial). Full ethical approval has been granted for the study (Wales REC 3 reference number 16/WA/0353).DiscussionCore outcome sets will be developed for short- and medium-term outcomes of research involving patients undergoing major lower limb amputation for PAD. This will help with the design of future trials and facilitate meta-analyses of trial data.Trial registrationPROSPERO: CRD42017059329. Registered on 30 March 2017.COMET: 975. Registered on 5 April 2017.

Elective Repair of Abdominal Aortic Aneurysm and the Risk of Colonic Ischaemia: Systematic Review and Meta-Analysis

INTRODUCTION Colon ischaemia (CI) is a significant complication of open (OR) and endovascular (EVAR) repair of abdominal aortic aneurysm (AAA). With a rapid increase in EVAR uptake, contemporary data demonstrating the differing rates and outcomes of CI between EVAR and OR, particularly in the elective setting, are lacking. The aim was to characterise the risk and consequences of CI in elective AAA repair comparing EVAR with OR. METHODS A systematic review and meta-analysis of the literature was performed using the Cochrane collaboration protocol and reported according to the PRISMA guidelines. PubMed, MedLine, and EMBASE were searched for studies reporting CI rates after elective AAA repair. Ruptured AAAs were excluded from analysis. RESULTS Thirteen studies reporting specific outcomes of CI after elective AAA repair, containing 162,750 evaluable patients (78,151 EVAR and 84,599 OR) were included. All studies found a higher risk of CI with OR than with EVAR. Three studies performed confounder adjustment with CI rates of 0.5-1% versus 2.1-3.6% (EVAR vs. OR) and combined odds ratio of 2.7 (2.0-3.5) for the development of CI with OR versus EVAR. The majority of cases of CI occurred within 30 days and were associated with variable mortality (0-73%) and re-intervention rates (27-54%). GRADE assessment of evidence strength was very low for all outcomes. There was a high degree of heterogeneity between studies both methodologically and in terms of CI rates, re-intervention, mortality, and time to development of CI. CONCLUSIONS EVAR is associated with a reduced incidence of CI compared with OR.

Major lower limb amputation audit – introduction and implementation of a multimodal perioperative pain management guideline

Bosanquet, David C., Ambler, Graeme K, Waldron, Cherry-Ann, Thomas-Jones, Emma, BrookesHowell, Lucy, Kelson, Mark, Harris, Debbie, Pickles, Timothy, Milosevic, Sarah, Fitzsimmons, Deborah, Saxena, Neeraj and Twine, Christopher P. 2018. Major lower limb amputation audit – introduction and implementation of a multimodal perioperative pain management guideline. British Journal of Pain 12 (4) , pp. 257-258. 10.1177/2049463718800736 file