Above-knee amputation (AKA) is typically a last-resort procedure in patients who are not candidates for limb salvage. Unplanned reoperation has been identified as a risk factor for increased morbidity and hospital readmission after vascular surgery.1 The objective of this study was to evaluate risk factors for unplanned reoperation after AKA.
A retrospective review was performed that included all patients who underwent 1 or more AKA by the vascular surgery service at 2 hospitals from January 1, 2013, to December 31, 2015. The level of amputation was determined by clinical examination, because adjunctive measures of tissue perfusion (ie, transcutaneous oximetry) were not used by these centers during this period. Data collected included standard demographics and comorbidities, perioperative data, and postoperative outcomes.
Institutional review board approval was received from University of South Florida and James A. Haley Veterans’ Affairs Hospital. Informed consent was waived for this retrospective review of deidentified data.
We used SAS version 9.4 (SAS Institute Inc) to calculate Pearson χ2 tests, Fisher exact tests, and logistic regression models, as appropriate. Statistical significance was determined by a P value less than .05, 2-sided. Data analysis occurred from July through December 2017.
Over the study period, 185 AKA operations were performed in 155 patients. Demographics, comorbidities, and postoperative outcomes are summarized in Table 1 and Table 2. The study population had a mean (SD) age at operation of 65 (13.3) years (with the age of patients who underwent reoperation included at each operation), and 118 of 155 patients were male (76.1%). Indications for amputation included tissue loss (58 of 185 operations [31.5%]), rest pain (21 of 185 [11.4%]), infection (73 of 185 [39.2%]), or 2 or more indications (33 of 185 [17.9%]). Seventy-five of 155 patients (48.4%) underwent prior ipsilateral revascularization (open or endovascular), and 75 patients (48.4%) had undergone prior ipsilateral amputation. Twenty-two revascularization procedures were for ipsilateral arterial inflow; however, this did not correlate with wound healing. There was a 15.7% rate of unplanned reoperation (29 of 185 operations), most often for a soft tissue wound revision (14 of 29 [48%]) followed by reamputation with a more proximal osteotomy (13 of 29 [45%]) and hip disarticulation (2 of 29 [7%]). Accounting for losses to follow-up, all-cause mortality rates were calculated as 11.3% (14 of 123 patients) at 30 days and 52.5% (31 of 59 patients) at 1 year.
Independent risk factors for reoperation on univariate analysis included prior ipsilateral revascularization (odds ratio [OR], 3.96 [95% CI, 1.60-3.80]), history of coronary artery disease (OR, 0.14 [95% CI, 0.04-0.50]), multiple indications for amputation (eg, ischemic wound with infection; OR, 2.47 [95% CI, 1.01-6.08]), presence of any postoperative complication (OR, 3.20 [95% CI, 1.35-7.59]), postoperative wound infection (OR, 3.04 [95% CI, 1.26-7.37]), wound dehiscence (OR, 11.50 [95% CI, 3.44-38.46]), and hematoma (OR, 32.29 [95% CI, 3.61-288.43]). On multivariate regression, prior ipsilateral revascularization (odds ratio [OR], 4.43 [95% CI, 1.45-13.45]; P = .009), multiple indications for amputation (OR, 6.44 [95% CI, 1.52-27.32]; P = .01), postoperative hematoma (OR, 17.82 [95% CI, 1.41-224.68]; P = .02), and wound dehiscence (OR, 7.99 [95% CI, 1.88-36.87]; P = .005) were found to be independent risk factors for unplanned reoperation after AKA. Reoperation was not associated with an increase in overall mortality. Notably, neither anticoagulation nor serum albumin were found to correlate with the need for reoperation.
Unplanned reoperation is a risk factor for increased postoperative morbidity and hospital readmission.1 This can be a devastating occurrence after AKA, with limited and highly morbid options for salvage after amputation failure. We have demonstrated a 16% reoperation rate after AKA in a cohort of patients presenting to a vascular surgery practice. This is higher than the rate reported among all comers in a recent large database study2 but similar to other retrospective series among patients with peripheral arterial disease.2,3 We found that patients with a history of prior revascularization were at a higher risk for reoperation; however, procedures performed to improve ipsilateral inflow to common and profunda femoris arteries were not protective against reoperation. Patients with wound complications, particularly hematoma, were highest risk for reoperation; however, the use of preoperative anticoagulation did not correlate with reoperation, contrary to previous reports.4 We attempted to account for metabolic risk factors. Serum albumin was not found to correlate, and few patients had preoperative hemoglobin A1c values collected. Although we were unable to determine the association of reoperation with functional outcomes after AKA, it is reasonable to assume a deleterious effect, given the already low likelihood of ambulation after an amputation at this level.5,6
In conclusion, this study found that patients with a history of prior revascularization, those with multiple preoperative indications for AKA, and those with postoperative wound complications are at increased risk for unplanned reoperation. Further study will be necessary to determine preoperative and perioperative adjuncts that will improve outcomes in this high-risk cohort.
Accepted for Publication: October 27, 2018.
Corresponding Author: Jeffrey B. Edwards, MD, Division of Surgery, Department of Vascular Surgery, University of South Florida, Two Tampa General Cir, 7th Floor, Tampa, FL 33606 (jeffreyedwards@health.usf.edu).
Published Online: February 6, 2019. doi:10.1001/jamasurg.2018.5074
Author Contributions: Dr Edwards had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.
Concept and design: Edwards, Wooster, Armstrong, Shames, Brooks.
Acquisition, analysis, or interpretation of data: Edwards, Wooster, Tran, Armstrong, Moudgill, Brooks.
Drafting of the manuscript: Edwards, Tran.
Critical revision of the manuscript for important intellectual content: Edwards, Wooster, Armstrong, Moudgill, Shames, Brooks.
Statistical analysis: Edwards, Wooster, Tran.
Administrative, technical, or material support: Wooster, Tran, Armstrong.
Supervision: Wooster, Armstrong, Moudgill, Shames, Brooks.
Conflict of Interest Disclosures: None reported.
6.Taylor
SM, Kalbaugh
CA, Blackhurst
DW,
et al. Preoperative clinical factors predict postoperative functional outcomes after major lower limb amputation: an analysis of 553 consecutive patients.
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