Question 8

What treatment strategy would you prefer?

A.  No possibilities for reconstruction. Choose the best medical treatment, then wait and see. B.  No possibilities for reconstruction. Foot-level amputation up to bleeding tissue. C.  Below-knee amputation.

D.  Possible acute debridement, reconstruction to pedal artery, and further wound excision later.

E.  No wound excision and reconstruction to pedal artery until the wounds are clean.

Question 9

If you consider vascular reconstruction, what would be your preferred inflow site in this patient?

A.  Common femoral artery. B.  Superficial femoral artery.

C.  Popliteal artery.

A popliteopedal reconstruction was made 5 days after admission to the vascular surgical unit. The great saphenous vein was used in situ with the supragenicular popliteal artery as aninflowvessel.Despiteachievinganacceptableinitialflowof51mL/min,thegraftthrombosed the next day and a thrombectomy and a revision of the graft was made. A narrow segment below the knee was replaced with a reversed proximal great saphenous vein under angioscopic control. A flow of 110 mL/min was measured with transit time flowmetry.

Question 10

Which of the following methods are adequate for intraoperative control?

A.  Angiography alone. B.  Doppler alone. C.  Flowmetry alone.

D.  Flowmetry with a method giving morphological information.

E.  Intraoperative duplex scanning alone.

The postoperative ABI was 0.97. Wound excision and three-ray amputation of the lateral toes were performed 2 days after revascularisation. The patient was discharged 2 weeks after admission and transferred to the community hospital. Split thickness skin grafting was performed there. The patient was discharged home with a heel-sandal (an offloading shoe in which the body weight is borne only by the heel), antibiotic treatment for one more week, and local wound care. The healing of the wound progressed well. Six weeks after the vascular reconstruction, the patient was prescribed insoles. He also used a silicon piece correcting the position of the second toe (Fig. 26.3).

b

At 1-year follow-up, ABI was greater than 1.3/0.91 and toe pressures were 65/55 mm Hg. Duplex surveillance findings indicated a possible vein graft stenosis.

Question 11

What are the findings indicating vein graft stenosis in the duplex examination?

A.  Midgraft peak systolic velocity (PSV) of less than 45 cm/s.

B.  V2/V1 ratio greater than 3 (V2, PSV at the site of the maximum stenosis; V1, PSV in the normal graft adjacent to the stenosis).

C.  Maximum PSV greater than 300 cm/s.

D.  End-diastolic flow velocity (EDV) greater than 20 cm/s.

A control angiography was performed, but no severe stenosis was found (Fig. 26.4).

26.1  Commentary

This case illustrates the problems related to delayed diagnosis and treatment of diabetic neuroischaemic foot. The aetiology of diabetic foot ulceration and infection is multifactorial. Our patient evidently had infection and also neuropathy. Neuropathy often abolishes sensation, and an unpleasant odour and discharge may be the first signs of infection to the

Fig. 26.4  Control angiography after 1-year follow-up

Table 26.1  Classification of diabetic foot lesions by grading and staging according to the depth of the lesion and the presence of infection and ischaemia, as proposed by Armstrong et al.2 Updated

Depth

 Grade 0: preor post-ulcerative site which has healed

 Grade I: superficial wound through the epidermis or epidermis and dermis which does not penetrate to tendon, capsule or bone

 Grade II: wound which penetrates to tendon or capsule

 Grade III: wound which penetrates to bone or joint

Infection and ischaemia

 Stage A: clean wound

 Stage B: non-ischaemic infected wound

 Stage C: ischaemic non-infected wound

 Stage D: ischaemic infected wound to tendon, capsule or bone

patient, especially if the lesion is situated on the plantar aspect of the foot. The role of microangiopathy in diabetic foot is not confirmed, but ischaemia due to atherothrombotic disease often plays a major role.1 [Q1: A, B, D]

The simplest method is to examine the ulcer with a blunt nasal probe. If it hits the bone, then osteomyelitis is most likely. The diabetic wounds should be classified systematically according to a precise system, such as the Armstrong classification (Table 26.1), which takes into account both the depth of the lesions and the presence of ischaemia and infection.2 Plain X-ray films are of limited value and magnetic resonance imaging (MRI) is the most reliable tool for diagnosis of osteomyelitis.3 [Q2: B]

The patient was reported to have palpable distal pulses at one time but not at another time. Furthermore, the popliteal pulse was reported to be palpable and ABI to be normal. Palpationoffootpulsesisnotafullyreproducibleobservation,andtheymaybeconsidered normal if both tibialis posterior and dorsalis pedis pulses are clearly felt.4 If either is not palpated,non-invasiveevaluationisnecessary.Itisfarmoredifficulttopalpatethepopliteal pulse, and it has been suggested that if an inexperienced palpator feels the popliteal pulse, this indicates an aneurysm. Systolic pressure measurements taken at the level of the ankle by a Doppler device are the most common non-invasive method for assessment of atherothrombotic disease. However, the results may be biased due to the presence of mediasclerosis, which is present in 15–40% of diabetics.5 Incompressible arteries may allow the signal to be heard in cuff pressures as high as the patient tolerates. In patients with mediasclerosis, the ABI typically exceeds 1.15.6 The audible Doppler signals may help the examiner, as an open inflow channel gives high-pitched biphasic signals but collateral flow around an occlusion usually gives only a low-pitched monophasic murmur. [Q3: A, B, C]

Symptoms of neuropathy include loss of sensation, hyperaesthesia and burning, and aching pain, which are often worse at night.7 Many patients with severe neuropathy are asymptomatic. Achilles tendon reflex, monofilament sensation testing and 128-Hz tuning fork testing are other recommended clinical tests.8 [Q4: A, B, C]

The primary diagnostic work-up in this case was clearly deficient. The patient obviously had osteomyelitis, which would have necessitated prompt drainage and amputation. Furthermore, the role of ischaemia should also have been evaluated and corrected within 3–5 days after proper drainage. [Q5: A, B]

The Doppler-derived pressures were clearly pseudohypertensive due to the arterial wall stiffness. Pseudohypertension affects digital arteries far less frequently, and therefore toe pressures are more reliable. A pulse volume recording at the ankle can also help to detect mediasclerosis. Another method is to measure systolic blood pressure at the ankle with Doppler but without an occluding cuff – the pole test.9 The examiner listens to the Doppler signals of the supine patient while the foot is elevated gradually until the signals disappear. Thescaleinthepolegivesthepressureattheankle(0.75×pressure(cm)equalsthepressure (mm Hg)). In centres where duplex scanning of distal arteries can be done by trained validatedexaminersthismethodwouldpreferablybethenextinvestigation.Magneticresonance angiography is also a method of choice if high-quality images are available and especially when the patient suffers from marked nephropathy. On the other hand in centres where technically demanding endovascular procedures can be done during diagnostic contrast angiography this is – as in our case – the primary imaging ­technique. [Q6: A, B, D, E, F]

Atherosclerotic changes in diabetes are typically situated in femoral and crural arteries, or only in crural arteries, in contrast to non-diabetic patients who tend to have the first symptoms from the obliteration of the aortic bifurcation. Despite proximal crural artery occlusion, the pedal arteries may be patent, as was the dorsalis pedis artery in this patient.

[Q7: A, C, E]

The treatment strategy is affected strongly by the presence and severity of infection. A superficial ulceration may be only the tip of the iceberg. There may be penetration, hidden to the eye, into deep tissues. Vigorous debridement must be carried out to establish the degree of penetration and to remove all necrotic tissue.3 Fulminant infection may necessitate guillotine amputation. The bypass can often be performed 3–5 days after debridement. If ischaemia plays a major role and the infection is quiescent, then revascularisation can, in selected cases, be performed first. Vascular reconstruction can be performed in as many as 90% of diabetic patients with peripheral arterial disease.10 The best outflow vessel in continuity with the foot should be selected.11 Diabetes is not considered to affect the outcome of graft patency, although female diabetic patients are reported to have worse outcome regarding patency and leg salvage.12 In limbs with large tissue defects, a microvascular free muscle flap transfer can be used for defect coverage in conjunction with long bypass.13 [Q8: D]

Short bypasses do well if the inflow artery is not compromised, as in our patient. Although the above-knee popliteal artery gave better results as the inflow vessel than the below-knee popliteal artery in our own series,14 the question is not settled. [Q9: C]

Angiography is the gold standard for intraoperative monitoring. The accuracy of flowmetry is affected strongly by the reproducibility of the method. In contrast to older methods, transit-time flowmetry, which does not require information on the diameter of the vessels, has proven to be very accurate.15 Despite this, it gives only flow values and does not inform about the morphology. The present case clearly shows how the typically narrow segment of the great saphenous vein below the knee was missed despite good flow during the initial hyperaemia. In this area, there was an intimal tear caused by the valvulectomy catheter. Unfortunately, an angioscope was not used in the first operation. An angioscope visualises the inner surface of the vessel, whereas intravascular ultrasound is better for detecting changes within the vessel wall. Doppler and duplex may be used for intraoperative monitoring as well. Doppler gives only haemodynamic information, whereas duplex gives a combination of anatomical and haemodynamic information. There is no best