Role of Revascularization in Transmetatarsal Amputation (TMA)

Educational Objectives

The goal of this program is to improve management of revascularization in transmetatarsal amputation (TMA). After hearing and assimilating this program, the clinician will be better able to:

1. Perform revascularization in TMA.

Summary

Historical perspective: transmetatarsal amputation (TMA) was first developed for trench foot; its use has been expanded to treat patients with chronic limb-threatening ischemia (CLTI)

Advantages: rate of healed TMA and a good functional status, with, eg, an assistive device, is 60% to 80%; for patients undergoing a major amputation the rate is <50%; according to evidence published over the previous 20 yr, 1-yr limb salvage rate is 50% to 70% and the 1-yr major amputation rate is 30% to 40%, the 3-yr survival rate is 35% to 65%; 30% to 40% have re-ulceration

Risk factors for failure of TMA: these include patients' low baseline ambulatory status, comorbidities (including end-stage renal disease), low albumin levels, extent of the tissue loss with wound stages 2 and 3, and ischemia

Role of the podiatrist: the podiatrist, dedicated to limb preservation, can assist with, eg, foot stability, and whether there is enough soft tissue coverage or whether plastic surgery will be required; the provider and patient should be committed to frequent follow-ups

Series of patients with TMA: for 180 TMAs in 165 patients from 2008 to 2016 in several San Francisco institutions, the median follow-up was 3.6 yr; the majority of these patients were diabetic (87%); 13% had WIfI scores of 1 or 2; most of these had multiple toe amputations in the past and so their final toe amputation resulted in a TMA; 90% were patients with extensive multidigit gangrene; 20% of patients were on dialysis; 54% of limbs had preoperative ABI or TBI testing, 31% of these limbs had toe pressures, 10% had an attempted ABI, and 27% had wounds that were too severe to allow ABI or TBI testing

Peripheral arterial disease (PAD) cohort: patients were older with more coronary artery disease and end-stage renal disease; survival was 70% at 3 yr vs patients without PAD (93%); overall limb salvage rates for patients without PAD was 91% vs 67% in patients with PAD; most patients with PAD progressed to above-knee or below-knee amputation ≤3 mo after TMA compared with patients without PAD (2-3 yr later)

Healing: primary healing — this was in 6 to 12 wk; secondary healing — included ongoing wounds requiring a repeat operation or long-term wound care; subjects with PAD had a lower rate of wound healing (55%); ≈30% of the patients with PAD had major amputations; non-PAD groups heal quickly; revascularization — in patients with GLASS stage III disease who underwent open vascularization, there was a 70% healing rate, and a 30% healing rate in patients who underwent endovascular revascularization

Studies in revascularization with TMA: Shi et al found that revascularizations before TMA was more likely to be successful; a subsequent study from the same author showed worse outcomes with endovascular surgery performed compared with open bypass surgery

Below-knee amputation (BKA) and above-knee amputation (AKA): researchers have used data from the Department of Veterans Affairs to assess outcomes after TMA, BKA, and AKA, including mobility, mortality, and the need for reamputation; amppredict.org — this was the culmination of a recent study in the European Journal of Vascular and Endovascular Surgery and is a decision support tool for patients undergoing a lower extremity amputation to predict survival, mobility, and the need for reamputation; very useful tool to show potential outcomes of a TMA using a graphic modality

Conclusion: TMA in patients with PAD is functional and durable; extensive arterial disease accompanies the extensive tissue loss and synchronous revascularization provides the highest rates of healing; a multidisciplinary team is valuable; the ratio of BKAs to TMA changed at the speaker’s institution from 6:1 to 1:1 with the involvement of limb-preservation specialists

Readings

Sheahan MG, et al. Lower extremity minor amputations: the roles of diabetes mellitus and timing of revascularization. J Vasc Surg. 2005; 42:476-480; doi: 10.1016/j.jvs.2005.05.003; Shi E, et al. Outcomes of wound healing and limb loss after transmetatarsal amputation in the presence of peripheral vascular disease. J Foot Ankle Surg. 2019; 58:47-51; doi: 10.1053/j.jfas.2018.07.004.

Disclosures

In adherence to ACCME Standards for Commercial Support, Audio Digest requires all faculty and members of the planning committee to disclose relevant financial relationships within the past 12 months that might create any personal conflicts of interest. Any identified conflicts were resolved to ensure that this educational activity promotes quality in health care and not a proprietary business or commercial interest. For this program, the following has been disclosed: Dr. Gasper reported nothing to disclose. In his lecture, Dr. Gasper presents off-label or investigational use of a therapy, product, or device.

Acknowledgements

Dr. Gasper was recorded at the UCSF Vascular Symposium 2021, held August 1-3, 2021, in Napa, CA, and presented by the University of California, San Francisco, School of Medicine, Department of Surgery, Division of Vascular and Endovascular Surgery. For information on future CME activities from this presenter, please visit http://vascular.surgery.ucsf.edu. Audio Digest thanks the speakers and meeting presenters for their cooperation in the production of this program.

ABS Continuous Certification

Successful completion of this CME activity, which includes participation in the evaluation component, enables the learner to earn credit/s toward the CME [and Self-Assessment] requirements of the American Board of Surgery’s Continuous Certification pro

CME/CE INFO

Accreditation:

The Audio- Digest Foundation is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians.

The Audio- Digest Foundation designates this enduring material for a maximum of 0 AMA PRA Category 1 Credits™. Physicians should claim only the credit commensurate with the extent of their participation in the activity.

Audio Digest Foundation is accredited as a provider of continuing nursing education by the American Nurses Credentialing Center's (ANCC's) Commission on Accreditation. Audio Digest Foundation designates this activity for 0 CE contact hours.

Lecture ID:

GS682104

Expiration:

This CME course qualifies for AMA PRA Category 1 Credits™ for 3 years from the date of publication.

Instructions:

To earn CME/CE credit for this course, you must complete all the following components in the order recommended: (1) Review introductory course content, including Educational Objectives and Faculty/Planner Disclosures; (2) Listen to the audio program and review accompanying learning materials; (3) Complete posttest (only after completing Step 2) and earn a passing score of at least 80%. Taking the course Pretest and completing the Evaluation Survey are strongly recommended (but not mandatory) components of completing this CME/CE course.

Estimated time to complete this CME/CE course:

Approximately 2x the length of the recorded lecture to account for time spent studying accompanying learning materials and completing tests.