A Series of 210 Peripheral Arterial Disease Below-Knee Amputations and Predictors for Subsequent Above-Knee Amputations

The misleading terminology of minor amputation of the lower limb

PURPOSE

A pronounced loss of function of the lower limb of various origins, especially with an infection-related course, may require a minor (MIN) or major (MAJ) amputation of the lower limb. Our aim was to contrast the underlying etiology, including previous trauma, surgical procedure, and the subsequent function.

METHODS

Between 2012 and 2022, 366 lower limb amputations were considered. After excluding isolated toe amputations and knee disarticulations, 80 amputations of 77 patients (66 male; 11 female; mean age: 57.2 years) were included in this monocentric retrospective study and their clinical outcome was evaluated. Briefly, 23 patients underwent MIN and 54 patients, including three bilateral cases, underwent MAJ. Patient demographics, etiology, level of amputation, prosthesis fitting, mobility based on the K-Level categories, SF-12 questionnaire, PLUS-M 12-item short form, and problems in coping with everyday life were recorded. The mean follow-up period was 3.9 years.

RESULTS

The mean SF-12 score of all patients was 36.9 (MIN: 37.24; MAJ: 36.85) for the physical summary component and 50.0 (MIN: 52.32; MAJ: 48.46) for the mental summary component; the mean Plus-M 12 score was 49.5 (MIN: 50,08; MAJ: 48,46) (p > 0.05). K-level 3 was the most common in all patients (MIN: 47.8%, MAJ: 42.6%), defined as an unrestricted outdoor walker.

CONCLUSION

With MIN and MAJ results comparable in all scores and queries, it emphasizes the fact that even supposedly lower-limb MIN represents a considerable impairment of coping with daily life. If there is no prospect of preserving the limb, early transtibial amputation should be considered. However, our results support the good outcome despite lower-limb MAJ through modern prosthetic fitting.

Botox in below knee amputation for the management of post-operative contracture: a systematic review

During the 1970s, scientists first used botulinum toxin to treat strabismus. While testing on monkeys, they noticed that the toxin could also reduce wrinkles in the glabella area. This led to its widespread use in both medical and cosmetic fields. The objective of the study was to evaluate the potential use of Botox in managing post-operative contracture after below-knee amputation. We conducted a systematic review In Pubmed, Cochrane Library, Embase, and Google Scholar using the MESH terms Botox, botulinum toxin, post-operative contracture, amputation, and below knee amputation. Our goal was to evaluate the potential use of Botox to manage post-operative contracture in patients who have undergone below-knee amputation. Our findings show evidence in the literature that Botox can effectively manage stump hyperhidrosis, phantom pain, and jumping stump, but no clinical trial has been found that discusses the use of Botox for post-operative contracture. Botox has been used in different ways to manage spasticity. Further studies and clinical trials are needed to support the use of Botox to manage this complication.

Clinical and Cardiovascular Profile in Patients With Peripheral Artery Disease

Background  Peripheral artery disease (PAD) is a vascular disorder leading to serious complications if not managed promptly. This study is conducted to analyze clinical and cardiovascular risk factors in PAD patients presenting at a tertiary care hospital and management strategies. Methodology This observational study was conducted at the Department of Cardiology, Mohamed Bin Khalifa Specialist Cardiac Centre. One hundred and twenty patients aged more than 35 years with PAD were included in the study. Data regarding age, gender, physical exam, cardiovascular risk profile, carotid disease, coronary artery disease, and treatment strategy were recorded on a pre-designed questionnaire by the researcher himself. The data were analyzed using IBM Corp. Released 2017. IBM SPSS Statistics for Windows, Version 25.0. Armonk, NY: IBM Corp. Results The mean age of patients with PAD was 65.46±10.56 years. About 79.2% were hypertensive, 81.7% had hyperlipidemia, 83.3% had diabetes, 29.2% had renal insufficiency, and 38.3% were active smokers, respectively. In age ≥65 years, infra-popliteal PAD was significantly lower as compared to above-knee PAD (23.4% vs. 76.6%, p=0.002). In diabetic patients, the proportion of above-knee PAD was higher than below-knee PAD (60% vs. 40%, p=0.033). Conclusion Older age, diabetes, and carotid disease were significant predictors for peripheral artery disease, and these are significantly associated with above-the-knee peripheral artery disease.

Mortality and Conversion to Transfemoral Amputation After Transtibial Amputation in the Veterans Affairs Health System

INTRODUCTION

Transtibial below-knee amputation (BKA) is associated with considerable morbidity, particularly in the vasculopathic population. The purpose of this study was to determine the cumulative probability of undergoing transfemoral above-knee amputation (AKA) conversion within 5 years of BKA and associated risk factors while accounting for the competing risk of death.

METHODS

This is a retrospective, national database study with structured query of the Veterans Affairs (VA) database for patients who underwent BKA from 1999 to 2020, identified by Current Procedural Terminology codes. Above-knee amputation conversion was identified using Current Procedural Terminology codes in combination with natural language processing to match procedure laterality. After internally validating our patient identification method, risk factors were collected. Competing risk analysis estimated the cumulative incidence rate of AKA conversion and associated risk factors with death as a competing risk.

RESULTS

Our query yielded 19,875 patients (19,640 men, 98.8%) who underwent BKA with a median age of 66 years (interquartile range, 60 to 73). The median follow-up was 951 days (interquartile range, 275 to 2,026). The crude cumulative probabilities of AKA conversion and death at 5 years were 15.4% (95% confidence interval [CI], 14.9% to 16.0%) and 47.7% (95% CI, 46.9% to 48.4%), respectively. In the Fine and Gray subdistribution hazard model, peripheral vascular disease had the highest AKA conversion risk (hazard ratio [HR] 2.66; 95% CI, 2.22 to 3.20; P < 0.001). Other factors independently associated with AKA conversion included urgent operation (HR 1.32; 95% CI, 1.23 to 1.42), cerebrovascular disease (HR 1.19; 95% CI, 1.11 to 1.28), chronic obstructive pulmonary disease (HR 1.15; 95% CI, 1.07 to 1.24), and previous myocardial infarction (HR 1.10; 95% CI, 1.02 to 1.19) (All P < 0.02).

DISCUSSION

Within this predominantly male, VA population, BKA carries a high risk of conversion to AKA within 5 years, without reaching a steady risk of AKA conversion within 5 years. Peripheral vascular disease, chronic obstructive pulmonary disease, cerebrovascular disease, previous myocardial infarction, and urgent BKA increase the risk of AKA conversion.

LEVEL OF EVIDENCE

Level III.

Comparison of angiographic and intravascular ultrasound vessel measurements in infra-popliteal endovascular interventions: The below-the-knee calibration study

BACKGROUND

Endovascular revascularization (ER) via percutaneous transluminal angioplasty (PTA) and stenting are viable options for revascularization in below-the-knee (BTK) peripheral arterial disease. Two-dimensional angiography has been the standard of practice for estimating vessel size and selecting treatment devices during ER. However, in other vascular territories, intravascular ultrasound (IVUS) offers better visualization of the lumen dimensions.

PURPOSE

To compare angiographic and intravascular ultrasound reference vessel (lumen) measurements in below-the-knee peripheral artery interventions.

METHODS

20 consecutive patients were enrolled in the BTK Calibration study from 2 sites in the United States and Australia. Patients with at least one diseased segment in a native infra-popliteal artery (below-the-knee) and a clinical indication for endovascular therapy (EVT) were included with no limitations with regards to vessel diameter or lesion length. Digital subtraction angiography and intravascular ultrasound imaging were collected pre-and post-percutaneous transluminal angioplasty and images were sent to an independent Core lab for standardized quantitative analysis of the normal-looking reference vessel dimensions when available. The results were presented as least square means with 95% confidence intervals and a p-value of <0.05 was considered as significant.

RESULTS

The overall (N = 19) mean reference vessel diameter for QVA was 2.98 ± 1.24 vs. 3.47 ± 0.72 for IVUS (mean difference was -0.50, (95% CI: -0.80, -0.20; p = 0.14). As expected in the proximal segments (N = 12), the mean reference vessel diameters were larger: for QVA was 3.17 ± 1.34 vs. 3.55 ± 0.76 in IVUS, (mean difference was -0.38, (95% CI:-0.79,0.03; p = 0.40); while in the distal segments (N = 7), mean reference vessel diameters were smaller: for QVA was 2.64 ± 1.06 vs. 3.33 ± 0.67 in IVUS, (mean difference was -0.69, (95% CI:-1.04,-0.34; p = 0.17). We observed a greater degree of acute gain in cases where the treatment balloon size correlated with the IVUS measured reference size.

CONCLUSION

Angiography underestimates infrapopliteal reference vessel lumen size even when quantitatively assessed. Adjunctive IVUS imaging use in guiding BTK procedures could help ensure adequate sizing and possibly impact immediate post-procedure indices.

Use of home negative pressure wound therapy in peripheral artery disease and diabetic limb salvage

Use of negative pressure wound therapy (NPWT) in peripheral artery disease (PAD) and diabetic limb salvage (DLS) improves wound healing by providing moist wound conditions, reducing exudate, controlling wound-bed infection, and stimulating granulation. NPWT duration may take several weeks, and home-based NPWT allows patient to recover in the community while minimising risks of prolonged hospitalisation. The aim of this study is to review the use and outcomes of home NPWT in PAD and DLS. The methodology is the retrospective review of patients who were discharged with home NPWT after in-patient PAD revascularisation and DLS debridement or minor amputations. The results included a total of 118 patients who received home NPWT between January 2017 and December 2017. The mean age was 62.8 years with 66% male and 34% female patients. The study population comprised 25% smokers, 98% patients with diabetics, 35% with ischemic heart disease, and 21% with end-stage renal failure (ESRF). Of which, 56% of patients required revascularisation while 31% of patients underwent foot debridement, 48% underwent toe amputations, and 20% underwent forefoot amputations. All patients received in-patient NPWT for a week before being discharged on home NPWT for 4 weeks. Then, 62% received targeted antibiotics regime while 36% received empirical antibiotics on discharge; 60% of patients achieved wound healing on home NPWT, with 9% requiring split-thickness skin graft; 4% required further surgical debridement, 16% required further minor amputation while 20% required major amputation. 9% required further home NPWT extension, with a mean length of 7.1 ± 4.7 weeks' extension. Overall survival of 1 year was 89%. Risk factors that predict the failure of home NPWT includes subjects with a background of ESRF and wet gangrene on presentation. Home NPWT is a useful adjunct in the management of PAD and DLS foot wounds.

Morphological and pharmacological characterization of the porcine popliteal artery: A novel model for study of lower limb arterial disease

OBJECTIVE

This study was undertaken to characterize structural and pharmacological properties of the pig popliteal artery in order to develop a novel system for the examination of lower limb blood flow regulation in a variety of cardiovascular pathologies, such as diabetes-induced peripheral artery disease.

METHODS

Popliteal arteries were isolated from streptozocin-induced diabetic pigs or age-matched saline-injected control pigs for morphological study using transmission electron microscopy and for examination of vasoreactivity to pharmacological agents using wire myography.

RESULTS

Transmission electron microscopy of the porcine popliteal artery wall revealed the presence of endothelial cell-smooth muscle cell interactions (myoendothelial junctions) and smooth muscle cell-smooth muscle cell interactions, for which we have coined the term "myo-myo junctions." These myo-myo junctions were shown to feature plaques indicative of connexin expression. Further, the pig popliteal artery was highly responsive to a variety of vasoconstrictors including norepinephrine, phenylephrine, and U46619, and vasodilators including acetylcholine, adenosine 5'-[β-thio] diphosphate, and bradykinin. Finally, 2 weeks after streptozocin-induced diabetes, the normalized vasoconstriction of the pig popliteal artery to norepinephrine was unaltered compared to control.

CONCLUSIONS

The pig popliteal artery displays structural and pharmacological properties that might prove useful in future studies of diabetes-associated peripheral artery disease and other lower limb cardiovascular diseases.

Predictors for reoperation after lower limb amputation in patients with peripheral arterial disease

Background: Major amputations in patients with peripheral arterial disease (PAD) carry a high risk for complications, including revision of the amputation, sometimes to a higher level. Determining a safe level for amputation with good wound healing potential depends largely on vascular measurements. This study evaluated potential predictive factors for revision of major lower extremity amputations in patients with PAD. Patients and methods: A retrospective chart review of all major lower extremity amputations at our institution was conducted. Amputations due to trauma or tumor and below-ankle amputations were excluded. Patient demographics, level/type of amputation, level/time of revision, comorbidities and risk factors were extracted. Results: 180 patients with PAD, mean age 66.48 (range: 31-93) years, 125 (69.4%) male were included. Most (154/180, 86.6%) underwent below-knee amputation. 71 (39.4%) patients had coronary arterial disease, 104 (57.8%) had diabetes. More than half of patients, (93/138; 51.7%) had undergone previous balloon angioplasty. 44 (30%) patients required revision surgery: 42/180 (23.3%) were revised at the same level, and in 12/180 (6.7%) a more proximal amputation was necessary. PAD stage was not associated with the level of reamputation (p = 0.4369). Significantly more patients who had previous balloon angioplasty required revision surgery (66.7% versus 45.2%, p = 0.009). 67 (37.2%) patients underwent preoperative TcPO2 measurement: 40/67 (59.7%) had TcPO2 ≥ 40 mmHg; 4/67 (6%) had TcPO2 < 10 mmHG. Three patients with TcPO2 ≥ 40 mmHg, one with 30 mmHg ≤ TcPO2 ≤ 40 mmHg and one with 10 mmHg ≤ TcPO2 ≤ 20 mmHg required re-amputation to a more proximal level. Conclusions: TcPO2 measurements are useful for determining level of lower limb amputation and predicting wound healing problems when an amputation level with TcPO2 < 40 mmHg is chosen. In transtibial amputations, TcPO2 ≥ 40 mmHg does not safely predict wound healing.

Review of Transmetatarsal Amputations in the Management of Peripheral Arterial Disease in an Asian Population

Objective: To evaluate outcomes after transmetatarsal amputation (TMA) in peripheral arterial disease (PAD) limb salvage in an Asian population and identify risk factors associated with TMA failure. Methodology: A retrospective review of 147 patients with PAD, who had undergone TMA between 2008 and 2014, was carried out. Univariate and multivariate analysis were used to identify predictors of TMA failure. Kaplan-Meier survival analysis was used to calculate major amputation and all-cause mortality rates. Results: The mean age was 66 years. 92% were diabetic patients and 78% had preceded angioplasty. 56% of TMAs were healed via secondary intention, 8% required subsequent split-thickness skin graft closure, 24% required further debridement while 37% had wounds, which failed to heal and required below-knee amputations (BKA). Multivariate analysis showed that diabetes is the only independent predictor of TMA failure (odds ratio (OR) 7.11, p=0.064). Patients with TMA failure were at increased risk of developing nosocomial infections (p=0.025) and faced a higher risk of 30-day re-admission rate (p=0.002). Conclusion: The success rate for PAD limb salvage TMA was 63% and diabetes was an independent predictor of TMA failure. Patients with TMA failure were at increased risks of nosocomial infections, and 30-day re-admissions; hence the risks and benefits of TMA for diabetic foot limb salvage must be individualized for each patient.