Fig. 19.15 Subtracted left femoral arteriogram (AP) at the level of the mid and distal thigh

Question 11

What is your impression?

A.  No change in his arterial status. The patient is exhibiting “drug-seeking” behavior B.  The superficial femoral artery stent graft is now occluded

C.  There is debris in the tibial peroneal arterial trunk which may represent emboli D.  Normal non-invasive test result

E.  Both B and C are correct

It is determined that open femoral to popliteal bypass graft is required for limb salvage. An exhaustive search in both upper and lower extremities does not reveal suitable autogenous vein for reconstructive arterial operation. You proceed with femoral to popliteal bypass graft employing synthetic arterial substitute as an alternative to major amputation of the limb and obtain an on-table completion angiogram (Fig. 19.17).

Question 12

Which statement is true about selection of graft material for femoral popliteal bypass for limb salvage?

A.  Autogenous tissue is the preferred conduit

B.  Composite autogenous tissue such as spliced together segments of cephalic vein is preferred over synthetic conduit

C.  Vascular Surgeons should be very reluctant to employ synthetic prosthesis for femoral popliteal bypass and search diligently for autogenous conduits

D.  Patients always prefer amputation over synthetic conduit

E.  Surgeon self-esteem is more important than limb salvage for the patient F.  A, B and C are all correct

19.1  Commentary

The patient in this clinical scenario has multiple risk factors for atherosclerosis and ­co-morbidities complicating his clinical presentation. Identification of risk factors and steps to modify them are to the patient’s benefit as is a program of supervised exercise. Nonetheless, this presentation warrants action beyond these measures as this patient will be at risk for limb loss in the near future when this condition progresses to tissue loss or even gangrene as is likely. Angiography is advised to plan intervention to avoid the natural history of this condition were it allowed to progress unchecked.1,2 [Q1: B]

The segmental arterial pressure and waveform studies are consistent with the history and physical exam. They demonstrate alterations in the waveforms and pressure on both sides in multiple arterial segments both above and below the inguinal ligament. The problem is demonstrably worse on the left (indexes at the ankle of 0.42 and 0.36) than it is on the right (indexes of 0.74 and 0.76). Incompressible arteries such as seen in diabetes mellitus patients would have erroneous pressure in the 300 mmHg or greater.1,3

[Q2: A]

Percutaneous transaxillary approaches have many useful applications. It is associated with a higher incidence of complications and manipulation for interventional work would only increase the risks.4–6 There is no need to employ a transaxillary approach when both femoral pulses are palpable. The translumbar approachfor angiographyhas anoble history and is still employed on occasion. There would be no opportunity for interventional work were it the selected approach and is not necessary with both femoral pulses present. Approaching from the right side has the potential benefit of allowing “up and over” crossing of the aortic bifurcation and potential antegrade balloon angioplasty or stenting for the symptomatic, left, side. [Q3: A]

Even with ultrasound localization and micropunture techniques to avoid puncture site complications, passage of wires in diseased arteries is not without hazards. Hydrophilic wires pass more easily but can undermine, dissect or even perforated atherosclerotic plaques. In this case a safer “J” wire dissected a plane in this very diseased vessel. The important maneuver when passage is difficult is to stop and obtain images and assess the situation thereby avoiding any substantial complications. [Q4: D]

With satisfactory appearance of the stented plaque that had been dissected there is no need to abandon the planned procedure. The pertinent diagnostic information is still lacking. Althoughadiagnosticangiogramcaneasilybeobtainedintheoperatingroomandadecision ispossibleyoualreadyhaveacatheterpositionedfornecessaryimagesandproceed.Transfer to the operating room for bypass or amputation is not needed or appropriate. [Q5: A]

The lesion demonstrated is a relatively long (several centimeters) chronic occlusion of the left superficial femoral artery. The occlusion is chronic because the collaterals are numerous, well developed and tortuous. It takes time for the muscular arteries to resound to the occlusion and manifest these characteristics. The distal superficial femoral is reconstituted by these collaterals originating from the deep femoral and the popliteal artery in turn patent as are the proximal infrapopliteal runoff arteries. [Q6: E]

The antegrade ipsilateral puncture of the common femoral artery is possible and it avoids the challenge in this patient of crossing a very diseased distal aorta that is configured in a narrow angle. One of the hazards is inadvertent passage of the guide wire into the deep femoral artery (demonstrated in this image, Fig. 19.6). The operator repositions the guide wire in to the superficial femoral artery and advances the introducer sheath over this wire. [Q7: C]

When a wire is successfully across a chronic total occlusion but is safely intra luminal beyond the lesion there are many options. Often times, traversing these lesions through the native lumen is not possible, but these lesions are able to be crossed through the subintimal plane, re-entering the true lumen in the distal target artery. The standard subintimal wire technique is most common, however if the distal target artery cannot readily be re-entered there are commercially available devices such as the Outback LTD Re-Entry Catheter (Cordis) that may be used to re-enter the true lumen. Once a wire is passed the lesion and in the true lumen many endovascular treatment techniques are available. Percutaneous subintimal angioplasty with selective stenting has been shown to be technically feasible and safe with satisfactory limb salvage rates. Long term durability is still a weakness of this therapy, but the durability of subintimal angioplasty is often reported better than that for prosthetic graft bypass.7–9 Many argue that laser is not the best choice nor is atherectomy although this is debated.10–12 In any case the rotating tip devices are for atherctomy, not thrombectomy. Mechanical thrombolysis would be ineffective were it attempted for chronic lesions that have organized and are the result of atherosclerotic plaques. Passing the wire is your and the patient’s best bet. [Q8: C]

Minor extravasation is not worrisome as long as it is clearly demonstrated that the wire is in the distal arterial segment. There is no need to convert to an open operation at this time and no place or need for embolization. Vascular Surgeons debate bare metal stenting versus covered stents. In this case with the extravasation we would argue for a covered stent. Recent results appear to favor covered stenting from a longer term patency rate.13–15

[Q9: C]