​Persons with diabetes are at risk of chronic limb-threatening ischaemia. While treating ischaemia is crucial, care beyond surgical treatment is also crucial to recovery. We share how a customised approach with a multidisciplinary team is the best approach to the disease.


Diabetes mellitus has increased in prevalence over the years and now affects 400 million globally.1

Diabetic patients are at risk of chronic limb-threatening ischaemia (CLTI) as 25% of them develop a foot ulcer, and 80% of major amputations begin as one.1

Many may not experience classic rest pain or prior claudication, and have a falsely raised ankle-brachial index. Poor perfusion, peripheral neuropathy and immunocompromised states lead to delayed presentation, extensive wounds and infections which render limbs unsalvageable.

While people are increasingly familiar with the diabetic foot from the media, relatives and friends, delayed presentation is common due to the initial ignorance or unnoticed tissue trauma. Others lack proper foot care, education and surveillance.

CLTI is part of a broad disease spectrum where treating ischaemia, while crucial, is only one determinant of success. Through a case study, this article hopes to show that customised treatment taken on by a multidisciplinary team is the best approach to the disease.2




Mr A was 55 years old and a smoker of 30 pack-years, with a body mass index (BMI) of 32.

He had been diabetic for five years (HbA1c 10.2%) and underwent coronary bypass at 54 years of age. He has stage 3 kidney disease and an incidental asymptomatic left carotid stenosis for which he declined intervention.


He presented with wet gangrene of his right second to fourth toes, associated with fever and hypotension three weeks after he knocked his toes during a brief syncopal episode.

Wet gangrene on toes - SingHealth Duke-NUS Vascular Centre


Mr A underwent emergent second-to-fifth-toe ray amputation with a plantar slit to allow drainage of purulent infection. His fifth toe was involved and had osteomyelitis on radiograph.

Post-debridement - SingHealth Duke-NUS Vascular Centre



Being a smoker with poorly-controlled diabetes, Mr A’s lower limb arterial duplex showed multi-level calcified steno-occlusive disease of the common femoral artery (CFA), superficial femoral artery (SFA) and below-the-knee (BTK) tibial disease. He had a toe pressure measurement of 15 mmHg.

ultrasound arterial duplex - SingHealth Duke-NUS Vascular Centre

Ultrasound arterial duplex of Mr A’s right lower limb


In stable patients, it is preferable to do same-setting revascularisation and amputation. However, when in septic shock, time is of the essence and the removal of the septic source must not be delayed.

 CLTI presenting as ulcers or absecesses - SingHealth Duke-NUS Vascular Centre

CLTI may also present as ulcers or abscesses in web spaces and pressure areas from ill-fitted footwear.

Long segment and small BTK tibial vessel disease with poor-to-no below-ankle perfusion is typical of CLTI patients.

angiographic images right and left legs - SingHealth Duke-NUS Vascular Centre


Angioplasty rather than bypass is the mainstay of treatment, but without established target outflow, primary amputation to an infection-free, well-perfused level may be the only option.

Use of imaging to guide treatment

In patients without a palpable femoral pulse and when the proximal inflow cannot be assessed on ultrasound, a computed tomography scan or magnetic resonance aortoiliac is required.

Concomitant aortic or proximal disease can be visualised and determines whether a contralateral retrograde or upper limb access is necessary for angioplasty.

In severely stenotic or occluded CFA disease, an open endarterectomy is preferred for a hybrid openendovascular procedure. It is thus useful to identify a non-calcified proximal ‘clamp-able’ segment and its relation to the inguinal ligament preoperatively for open surgery.

Imaging can also show acute or subacute features where thrombolysis or thrombectomy with aspiration devices may be required.

Contrast use for imaging and angioplasty may worsen renal function. This can be minimised with the use of carbon dioxide for angiograms, pre-surgery hydration and avoidance of nephrotoxic agents.

Endovascular therapy

Endovascular therapy is well-established for lower limb revascularisation.3

A sheath is placed in an access vessel under ultrasound guidance (usually CFA) and a digital subtraction angiogram (DSA) is performed. Intra-arterial heparin is administered and wires are used to transverse vessel lesions so as to deploy balloon(s) across.

Balloon insufflation establishes lumen, treating the stenosis or occlusion.

SAFARI technique

In long segment disease, it is sometimes necessary to employ a subintimal arterial flossing with antegrade-retrograde intervention (SAFARI) technique where ‘true lumen’ percutaneous access from two directions is used to ‘cross a lesion’ to obtain a through and through passage.

Increasingly, atherectomy devices are used to achieve luminal gain before balloon angioplasty to reduce vessel dissection.


Stenting is necessary when there is significant or persistent vessel recoil, dissection, high clot burden and perforation. They are costly and surveillance is required as they can re-stenose or occlude over time.

Data for and against drug elution technology (paclitaxel- or sirolimus-based) exist.4 These are generally used for short-interval recurrent disease and may add duration to vessel patency.


Angioplasty aims to provide straight-line flow to the wound that is ideally angiosome based, or to re-establish a plantar arch when possible.


When flow cannot be achieved in an interveningmsegment (e.g., SFA) or in stent failure, a bypass option with native vein or graft is possible.

Bypass procedures have higher perioperative risks, longer operative times and hospital stays. They are at risk of wound and graft infections and are subjected to the availability of conduits such as native veins.Native-vein, above-tibial bypasses have the best long-term results.

Bypasses are performed for fitter patients with reasonable premorbid ambulatory status and cardiac ejection fraction.



Mr A underwent a hybrid procedure consisting of an open common femoral endarterectomy, followed by a bovine patch repair. A sheath was then placed antegrade into the patch to perform the angiogram and angioplasty of the infrainguinal vessels.

Femoral endartectomy and patch repair - SingHealth Duke-NUS Vascular Centre

Femoral endarterectomy and patch repair along with removed calcified plaque

Angiographic images - SingHealth Duke-NUS Vascular Centre

Angiographic images showing CFA patch puncture, femoral popliteal disease, balloon dissection, stent deployment and restored flow

BTK-anterior tibial angioplasty (ATA), posterior tibial artery (PTA) SAFARI - SingHealth Duke-NUS Vascular Centre

BTK-anterior tibial angioplasty (ATA), posterior tibial artery (PTA) SAFARI

Distal percutaneous transluminal angioplasty and common plantar angioplasty - SingHealth Duke-NUS Vascular Centre

Distal percutaneous transluminal angioplasty and common plantar angioplasty



Monitoring and care

Wound healing requires appropriate culture-directed antibiotics, avoidance of new trauma, maintaining perfusion and optimising care of existing cardiac, renal, glycaemic, ambulatory and nutritional status, while going through ongoing rehabilitation.

Prolonged stays with immobility lead to the development of pressure sores and nosocomial infections, and must be avoided.

The antibiotic duration depends on wound progress and the presence of existing infections such as osteomyelitis or bacteraemia. Inflammatory markers are useful adjuncts and an infectious diseases physician is often consulted.

Vascular access lines may be needed when prolonged treatment is required, but pose a threat when infected and require frequent examination.

Repeat angioplasty may be needed if wound healing is impaired.

Vascular teams, along with dedicated wound nurses and podiatrists, perform regular wound inspections, debridement and dressing changes.

A variety of dressing options including antiseptic solutions, cellulose/collagen-based dressings, hydrocolloids, vacuum-assisted closure devices and hyperbaric therapy or oxygen delivery devices are available for different types of wounds.

Continued wound care

Continued wound care is paramount for success, and step-down facilities such as community hospitals, day care and home nursing facilitate rehabilitation till patients or caregivers are confident to be independent at home.

Wounds contracting and granulating well - SingHealth Duke-NUS Vascular Centre

New heel wounds - SingHealth Duke-NUS Vascular Centre 

Recovery of heel and pressure wounds

Heel and pressure wounds are challenging as blood flow is poor and offloading, despite best efforts, may not be possible due to immobility.

Wounds after revascularisation are in a race against time as they have a risk of reinfection or deterioration.

Those that granulate well and have been treated for infection should pursue coverage in the form of skin graft or flap performed by either vascular or plastic surgery.

Wounds that have deteriorated and healed well - SingHealth Duke-NUS Vascular Centre

Recovery from major limb amputation

A timely decision to perform amputation will save lives. However, acceptance can be stressful and requires dedicated physicians, social workers and rehabilitation teams.

When the stump heals, many enjoy sepsis-free, excellent quality of life with earlier return to society and eventual prosthesis fitting.

Well-healed amputation stumps and extensive wounds better with primary amputation - SingHealth Duke-NUS Vascular Centre



Mr A’s wound healed well with split skin graft and he regained reasonable ambulation after six months.

Two years on, he required a below-the-knee amputation of his other leg when he re-presented with heel gangrene and calcaneal osteomyelitis. Help was sought late due to depression and worries over job commitments. He eventually required hemodialysis as his kidneys failed.

Fortunately, his forefoot remained well and he eventually learned to walk with a below knee prosthesis.

He no longer has open wounds and is able to hold a clerical job. He gets around with a personal mobility device and most importantly, enjoys time with his grandchildren.


The Singapore General Hospital Department of Vascular Surgery performs an average of 400 lower limb angioplasties a year and collaborates closely with the Department of Interventional Radiology.

A retrospective review of 3,303 angioplasty procedures performed on 2,402 limbs from 2005 to 2015 showed salvage rates of 75%, 72% and 62%, and overall survival rates of 79%, 56% and 34% at 1, 5 and 10 years respectively.5

The department performs open and hybrid procedures, manages wounds and treats a variety of renal, carotid and aortic conditions. 


A vascular consultation is always advised for CLTI.

The treatment varies depending on comorbidities, activities of daily living function, extent of tissue loss, as well as social background and personal beliefs and attitudes. Limb salvage, while ideal, may not always be possible or permanent.

Many go through great physiological and psychological ordeals, and expenses and caregiver stress put a strain on relationships. Others may seek alternative (harmful) therapy or slide into depression.

GPs have preventive roles and can participate in education, wound and emotional care.



  1. J.L. Mills Sr., M.S. Conte, D.G. Armstrong, F.B. Pomposelli, A. Schanzer, A.N. Sidawy, et al., Society for Vascular Surgery Lower Extremity Guidelines Committee, The Society for Vascular Surgery lower extremity threatened limb classification system: risk stratification based on wound, ischaemia, and foot infection (WIfI); J Vasc Surg, 59 (2014), pp. 220-234.e1-234.e2
  2. Chung J, Modrall JG, Ahn C, Lavery LA, Valentine RJ. Multidisciplinary care improves amputation-free survival in patients with chronic critical limb ischaemia. J Vasc Surg. 2015 Jan;61(1):162-9. doi: 10.1016/j.jvs.2014.05.101. Epub 2014 Jul 26. PMID: 25073577.
  3. DeRubertis BG, Faries PL, McKinsey JF, Chaer RA, Pierce M, Karwowski J, Weinberg A, Nowygrod R, Morrissey NJ, Bush HL, Kent KC. Shifting paradigms in the treatment of lower extremity vascular disease: a report of 1000 percutaneous interventions. Ann Surg. 2007 Sep;246(3):415-22; discussion 422-4. doi: 10.1097/SLA.0b013e31814699a2. PMID: 17717445; PMCID: PMC1959357.
  4. Katsanos K, Spiliopoulos S, Kitrou P, Krokidis M, Paraskevopoulos I, Karnabatidis D. Risk of Death and Amputation with Use of Paclitaxel-Coated Balloons in the Infrapopliteal Arteries for Treatment of Critical Limb Ischaemia: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. J Vasc Interv Radiol. 2020 Feb;31(2):202-212. doi: 10.1016/j.jvir.2019.11.015. Epub 2020 Jan 15. PMID: 31954604.
  5. Ni WW, Leong S, Irani F, Patel A, Damodharan K, Venkataranasimha N, Chandramohan S, Kumar P, Chua J, Gogna A, Da Zhuang K, Chong TT, Tang TY, Chng SP, Tay KH. “Angioplasty-First” Approach for Limb Salvage in Asian Patients with Critical Limb Ischaemia: Outcomes from 3,303 Angioplasties on 2,402 Limbs in a Single Tertiary Hospital. J Vasc Interv Radiol. 2020 Dec;31(12):1969-1977.e1. doi: 10.1016/j.jvir.2020.08.008. Epub 2020 Nov 1. PMID: 33139186.


Dr Nick Ng Zhi Peng is an Associate Consultant at the Department of Vascular Surgery in Singapore General Hospital. He graduated from the Yong Loo Lin School of Medicine, National University of Singapore in 2011 and completed his surgical training with the SingHealth General Surgery Residency Programme in 2018. He obtained his Masters of Medicine (Surgery) in 2017 and FRCS (Edinburgh) in March 2019. He has an interest in both open and endovascular surgery and hopes to help patients with chronic limb threatening ischaemia have the best possible quality of life.

GPs can call the SingHealth Duke-NUS Vascular Centre for appointments at the following hotlines:

Singapore General Hospital: 6326 6060
Changi General Hospital: 6788 3003
Sengkang General Hospital: 6930 6000
KK Women’s and Children’s Hospital: 6294 4050
National Heart Centre Singapore: 6704 2222