Time and tides. Interview by Chris Serb.
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Biomedical subjects
Publications and source records attributed to J Pecoraro.
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Interval gangrene, segmental ischemic necrosis proximal to a functioning distal anastomosis, is a rare complication after successful peripheral vascular reconstruction. Previous reports have demonstrated the gravity of this event in that major limb amputation was required in all cases. Two cases are presented to emphasize the need for maintaining segmental collateral circulation after successful distal extremity bypass. Despite a satisfactory result after distal (inframalleolar) bypass of a popliteal aneurysm, one patient had progressive ischemic gangrene of the upper leg and eventually required amputation. The contralateral limb was successfully managed by distal ligation of the superficial femoral artery, which maintained collateral flow from the proximal superficial femoral artery to the knee and leg. The second patient required a microvascular free flap to replace tissue loss and provide vascular graft coverage after initial multiple bypass failures and a final successful remote reconstruction to the dorsal artery of the foot that excluded the popliteal-crural collateral network. Patients with inadequate collateral circulation or disruption of the profundus or geniculate collateral pathways may require revascularization of sequential vascular beds. Recognition of the potential for interval gangrene is essential since the likelihood of its occurrence will increase in proportion to the number of distal bypasses being performed for limb salvage. Although adjunctive procedures will not completely eliminate the possibility of interval gangrene, awareness of this phenomenon with attention to the segmental collateral circulation can decrease the incidence of its occurrence.
From November 1979 through December 1989, 210 distal arteriovenous fistulas were constructed as adjuncts to tibial and peroneal vascular reconstructive procedures in 203 patients threatened with limb loss. Two-year cumulative patency rates were calculated by grouping patients on the basis of changing indications in sequential time periods: group 1 (n = 61): 1979 to 1983, 18%; group 2 (n = 80): 1983 to 1986, 33%; group 3 (n = 69): 1986 to 1989, 44%. Although the therapeutic results observed in these groups are not statistically comparable, they show a perceptible trend. Postoperative arteriography showed that flow is prograde in the distal vessels beyond the distal arteriovenous fistula. Graft surveillance by duplex ultrasonography also confirmed that flow in the distal arteries is prograde and that "steal" does not occur. Peak systolic velocity (174 +/- 38 cm/sec) and mean velocity (92 +/- 23) flow rates are increased in grafts with patent distal arteriovenous fistulas compared to those bypasses with closed distal arteriovenous fistulas (p less than 0.01). There were no differences in the flow measurements for the arteries beyond the distal anastomoses and distal arteriovenous fistulas, confirming the prograde nature of the distal flow. In 22 patients analysis of graft and fistula patency by duplex sonography showed that one fourth of all grafts were patent without fistulas at 1 and 2 years after operation. Alternatively, 68% of patent grafts at 1 year had patent fistulas and 58% had patent fistulas at 2 years. We conclude that the distal arteriovenous fistula will increase graft flow and simultaneously prevent distal arterial overload without causing "steal." This technique should be considered whenever a prosthetic graft is necessary for crural reconstruction and only in selected instances of revascularization with autologous veins.
Over a 12-year period, 160 transmetatarsal amputations were performed in patients with peripheral vascular occlusive disease. The following groups were defined: group 1 - nonreconstructable disease (n = 40); group 2 - transmetatarsal amputation in conjunction with distal revascularization (n = 99); group 3 - reconstructable disease but transmetatarsal amputation performed without simultaneous revascularization (n = 21). There were nine early deaths in the entire series, for an operative mortality rate of 5.6%. The lowest rate of transmetatarsal amputation healing (24%) occurred in group 1. An 86% healing rate was achieved in group 3, but in seven cases (33%) some type of revascularization was required within 3 months of the amputation. In group 2 the healing rate was 62% but reached 83% where the bypass remained patent for at least 3 months after the amputation. Long-term patency rates also affected healing. Healing was not influenced by the number of local procedures (single vs multiple). The presence of severe infection or extensive necrosis necessitated open transmetatarsal amputation in 89 cases; the remaining 71 amputations involved primary closure. Since many patients were treated at a time when diagnostic modalities as well as the operative indications and techniques differed somewhat from the current practice, much of the information regarding group I patients in particular should be considered as a negative historical control and any conclusion from our data should be adjusted accordingly. Healing after amputation at the transmetatarsal level can be expected in the majority of instances in which revascularization can be performed with predictable patency, even when the standard criteria for performing such amputations are liberalized.(ABSTRACT TRUNCATED AT 250 WORDS)