# Effectiveness of a Glyceryl Trinitrate (GTN) Patch in Preventing Amputation, Improving Pain Control and Reducing the Size of Tissue Loss for a Patient With Critical Limb-Threatening Ischaemia (CLTI)

## TL;DR

A glyceryl trinitrate (GTN) patch helped prevent amputation, reduce pain, and improve healing in patients with severe leg blood flow issues.

## Contribution

This pilot study demonstrates the off-licence use of GTN patches as an effective treatment for critical limb-threatening ischaemia.

## Key findings

- 93% of patients avoided amputation with GTN patch use.
- 84% of patients experienced improved pain control and ulcer/gangrene reduction.
- GTN patch showed statistically significant benefits over expected 50% outcomes.

## Abstract

Background

Foot ulcer is a common complication of poorly controlled diabetes and peripheral vascular disease (PVD). The current standard of treatment for diabetic foot ulcers includes the management of underlying risk factors, wound debridement, use of antibiotics for infection, off-loading with cast, and revascularisation surgery. The glyceryl trinitrate (GTN) patch is currently off-licence in treating PVD or diabetic foot ulcers. This study aims to evaluate the effectiveness of the GTN patch in preventing amputation, improving pain control, and reducing the size of tissue loss (ulcer/gangrene) or localised ischaemic area.

Method

This is a pilot study of 30 patients who were started on the GTN patch from February 2020 to October 2021. Inclusion criteria were patients who have critical limb-threatening ischaemia (CLTI) and with no viable options or are at high risk for revascularisation, both endovascular and open surgery. Patients who were on a GTN patch for less than six weeks at the time of data collection or had unclear outcomes were excluded.

The outcomes were retrospectively collected on prevention of amputation, improvement in pain control, and reduction in tissue loss (the size of ulcer/gangrene) or localised ischaemic area with the use of a GTN patch. The binomial test was used to compare the observed outcome of the GTN patch and the expected outcome, which was assumed to be 50% in this study.

Results

Ninety-three per cent (93%) of the patients who had GTN patches successfully avoided amputation (p<0.0001). Eighty-four per cent (84%) of patients reported better pain control (p=0.0022) and improvement in the size of ulcer/gangrene/localised ischaemic areas (p=0.0005).

Conclusion

The GTN patch is effective in preventing amputation, improving pain control, and reducing the size of ulcer/gangrene/localised ischaemic areas in patients who have end-stage CLTI and no viable options or who are at high risk for revascularisation surgery.