Allastair M. Karmody

Suggested standards for reports dealing with lower extremity ischemia

Reports in the vascular surgery literature are often difficult to assess and compare with each other because of poorly defined terms, imprecise categorization, lack of indices for gauging the severity of the disease or the presence of risk factors capable of affecting outcome, and varying criteria for success or failure--in essence, a lack of standardized reporting practices. The joint councils of the Society for Vascular Surgery and the North American Chapter of the International Society for Cardiovascular Surgery have appointed an ad hoc committee to deal with this problem. This report represents the recommendations of the first of its several subcommittees, that is, the one dealing with reports on lower extremity ischemia. Certain terms are defined and criteria offered for uniformly gauging the severity of disease, the findings of diagnostic studies, the types of therapeutic interventions, and the outcome of such treatments. Although future modifications may further improve on this effort, it is hoped that this committees recommendations will help establish reporting standards for articles dealing with lower extremity ischemia.

Instrumental evolution of the valve incision method of in situ saphenous vein bypass

The previously stated advantages of the valve incision method of in situ saphenous vein arterial bypass have now been confirmed by others. However, this method has been limited by its time-consuming technical demands. Considerable experience with this bypass in conjunction with retrograde serial valve disruption with instruments of similar design principle (by Hall and Cartier) has been accumulated in Europe. However, the combination of the trauma of blunt valvular fracture and the sensitivity of endothelium to frictional shear has precluded use of these instruments in veins less than 4 mm in size, and the results have not been significantly better than those obtained with reversed vein bypass. An instrument (valve cutter) that achieves serial valve incision safely and consistently without mandatory exposure of each valve site has now been developed. Of the last 166 consecutive bypasses, the saphenous vein was suitable for use of this instrument in 116 instances (70%). The patency of these bypasses as determined by life-table analysis has shown no significant difference when compared with bypasses performed under similar conditions in which the cutter was not used. On the basis of this investigative and clinical experience, the majority of in situ saphenous vein arterial bypasses can be safely facilitated and simplified by use of this instrument.

The anatomy of the greater saphenous venous system

To define surgical anatomy, a prospective study of the greater saphenous venous system in 385 instances in 331 patients was carried out with the use of prebypass phlebography (either pre- or intraoperative). The phlebographic interpretations were confirmed during the operative procedures and from the completion angiogram. These details were recorded and analyzed by a specific computer program. These data consisted of a number of superficial branches, perforators, the identification of valve leaflets, sinuses, and the size and position of the main venous trunk both in the thigh and in the calf. The study showed that a single trunk was present in the thigh in 65% of patients and in the calf in 45%. The remainder were variants of double systems. In two thirds of patients who had complete double systems, the larger system was used for in situ bypass but the rest required the use of parts of both systems. Phlebography was accurate in the depiction of the anatomic variations (93%), double systems, cross connections, and perforator branches (87%). However, the number of competent valves could not be accurately determined (accuracy, 68%). The diameter of the vein was frequently underestimated (in 80% by 1.1 +/- 0.4 mm) and hence could not be used as an index of vein adequacy. After phlebography, four patients had transient rises in serum creatinine levels and one had an iatrogenic thrombosis of a distal segment. This study suggests that the precise anatomy of the greater saphenous venous system should be determined preoperatively by phlebography since this information is valuable for proper surgical planning before vein is used as a graft or for in situ bypass in the lower extremity.

Polytetrafluoroethylene grafts in the rapid reconstruction of acute contaminated peripheral vascular injuries.

Conventional wisdom dictates that autogenous tissue interposition be used in contaminated wounds when direct vascular repair is not feasible. Although there are few reports of successful use of PTFE grafts in grossly contaminated wounds, doubt still exists regarding the use of any prosthetic material in such wounds for reconstruction of vascular injury. Twenty-five vascular reconstructions were performed in 20 patients during a 3.5 year period. These patients had life-threatening multiple trauma and severe local tissue damage along with their arterial and venous injuries in open contaminated wounds after blunt (16 patients) and penetrating (4 patients) trauma. In all patients, 6 mm PTFE was used for interposition bypass for arterial injuries, and in five of these patients, 8 mm PTFE was used for concomitant venous interposition bypass. One patient died and there was one arterial and one venous graft thrombosis in the same patient 3 months after a shotgun blast injury to the groin, but there was no limb loss. All other grafts remained patent without wound infection, sepsis, or anastomatic disruption. Under the circumstances of these peripheral vascular injuries, PTFE was an acceptable choice for primary reconstruction in our patients. Its ready availability in many calibers, sparing of autogenous vein for future use, and its expedience in vascular reconstruction comprise the advantages of using PTFE in multiply traumatized patients without producing the feared evidence of infected prosthetic grafts.

Peroneal artery bypass: A reappraisal of its value in limb salvage

In general the surgical literature has expressed pessimism about the value of bypass to the peroneal artery for limb salvage. The combination of greater technical difficulty, low patency rates, and hemodynamic failures have led to the establishment of this prejudice. In a review of 284 arteriograms in limbs with infrapopliteal arterial occlusion, the peroneal artery was the least diseased in 40% and was the only available vessel in 37% of instances. One hundred fifty-two peroneal bypasses have been performed in a 7-year period, 116 by the in situ method, 23 with excised vein, and 13 by nonautogenous conduits. During the same period 125 anterior tibial and 114 posterior tibial bypasses were also done. The mean preoperative ankle/brachial indices were 0.27 for peroneal, 0.25 for anterior tibial, and 0.29 for posterior tibial bypasses. These were converted to mean postoperative indices of 0.84, 0.86, and 0.92, respectively. Corresponding transmetatarsal/brachial indices were 0.72, 0.75, and 0.90. Rest pain was relieved in all these patients, and in 94 patients with tissue loss, there were 11 major amputations, nine healed forefoot amputations, and 20 healed digital ray amputations. Hemodynamic failures were two in the peroneal, two in the anterior tibial, and three in the posterior tibial group with one perioperative amputation in each. The cumulative limb salvage rate at 3 years for the peroneal group was 81%. This experience has shown that the patency and limb salvage rates obtained are comparable to those for the anterior and posterior tibial arteries and that hemodynamic failure is an uncommon occurrence.(ABSTRACT TRUNCATED AT 250 WORDS)

Pathologic interactions between prosthetic aortic grafts and the gastrointestinal tract: Clinical problems and a new experimental approach

Twenty-one patients presented with pathologic interactions between the gastrointestinal tract and aortic grafts. Seventeen patients were managed by excision of the graft and axillobifemoral bypass. Six patients died. four deaths were due to disruption of the proximal aortic stump after initial therapy that appeared successful. An experimental model of a seromuscular jejunal patch is presented that may be beneficial for closure of the proximal aortic stump.

Further experience with the saphenous vein used in situ for arterial bypass

Ongoing experience with use of the saphenous vein in situ as in infrainguinal arterial bypass is presented. One hundred eighty-three bypasses were performed for limb-threatening ischemia, 92 of which were to the popliteal artery, either isolated or in continuity with one or more tibial vessels, and 91 bypasses were carried to single tibial vessels below the termination of the popliteal artery. The results were analyzed by the life table method and show an overall patency rate of 89.8 percent at 3 to 4 years. Separate life table analysis of the tibial bypass group showed a patency rate of 83 percent at 3 to 4 years. Special emphasis is placed on the ability to use veins less than 4 mm in diameter, which comprise 40 percent of those used in these procedures. The superior results provided by the in situ method are explained in part by experimental observations which show that endothelial stability is completely preserved by this method but is severely disturbed during the process of vein removal and reversal.

Advances in the management of acute popliteal vascular blunt injuries

This report evaluates critical points in the management of 30 consecutive blunt traumatic popliteal vascular injuries. All arterial injuries were diagnosed both clinically and by Doppler and PVR examinations. Twenty-eight of the 30 arterial reconstructions required interposition bypass grafts, nine of which were PTFE and the remainder were autogenous saphenous veins. In 19 patients the distal anastomosis was made to the distal popliteal artery and in nine patients to the tibial-peroneal arteries. In ten patients in whom limb survival was threatened, the ischemic time was shortened by the use of temporary Silastic shunt for rapid restoration of arterial flow. Nine patients had associated venous injuries which were repaired. Nine of the first 14 patients required fasciotomy but the last 16 patients were treated with hypertonic mannitol and only two of them required fasciotomy. There were no amputations, but in four limbs there were functional losses. In spite of the more extensive damage of blunt trauma, prompt and aggressive management aided by vascular laboratory tests, indwelling shunt, and hypertonic mannitol is rewarded with preservation of limbs following acute popliteal vascular injuries.

Optimal management of tibial arterial trauma.

In an attempt to define optimal management, we have studied the outcome of 29 isolated tibial arterial injuries during the past 4 years. Twenty-five patients suffered blunt and four had penetrating trauma. Twenty-seven patients had preoperative arteriography which showed at least one interrupted tibial artery. In nine patients, immediate and successful reconstruction was done. Since the foot was viable in 20 patients, immediate reconstruction was not carried out in spite of the diagnosis of tibial arterial injury. Three of 20 underwent primary amputation. Fifteen of the remaining 17 patients required further angiographic evaluation for arterial reconstructions 2 to 12 months later for nonhealing of wounds, malunion of fractures, and soft-tissue defects. Delayed reconstructions were generally more complex. In 13 patients both viable and functional feet were eventually achieved. Bypass with autogenous vein was mandatory for success. Our experience has shown that most tibial arterial trauma will require immediate repair for success. Delayed repair was more difficult and was associated with substantial limb loss.

Initial experience comparing B-mode imaging and venography of the saphenous vein before in situ bypass

Preoperative saphenous vein assessment was performed using both venography and B-mode scanning. Fifty patients underwent preoperative assessment, and the results were compared with the intraoperative findings. Both venography and B-mode imaging were equally accurate at determining the dominant saphenous system, but B-mode imaging missed five thigh double systems that were shown on venography. Neither venography nor B-mode imaging were good predictors of actual vein size at most sites in the leg, with the exception of B-mode assessment below the knee, where there was a positive correlation with intraoperative vein size (r = 0.80; p less than 0.01). In our study, B-mode scanning was consistently more reliable in determining vein presence and continuity than venography, which gave nine false-negative results. Finally, B-mode imaging allows the marking of a saphenous vein map on the patients leg preoperatively as a guide to bypass surgery.