Thomas H. Schwarcz

Surgical Management of Thrombotic Acute Intestinal Ischemia

ObjectiveTo evaluate the University of Kentucky experience in treating acute intestinal ischemia to elucidate factors that contribute to survival. Summary Background DataAcute intestinal ischemia is reported to have a poor prognosis, with survival rates ranging from 0% to 40%. This is based on several reports, most of which were published more than a decade ago. Remarkably, there is a paucity of recent studies that report on current outcome for acute mesenteric ischemia. MethodsA comparative retrospective analysis was performed on patients who were diagnosed with acute intestinal ischemia between May 1993 and July 2000. Patients were divided into two cohorts: nonthrombotic and thrombotic causes. The latter cohort was subdivided into three etiologic subsets: arterial embolism, arterial thrombosis, and venous thrombosis. Patient demographics, clinical characteristics, risk factors, surgical procedures, and survival were analyzed. Survival was compared with a collated historical series. ResultsAcute intestinal ischemia was diagnosed in 170 patients. The etiologies were nonthrombotic (102/170, 60%), thrombotic (58/170, 34%), or indeterminate (10/170, 6%). In the thrombotic cohort, arterial embolism accounted for 38% (22/58) of the cases, arterial thrombosis for 36% (21/58), and venous thrombosis for 26% (15/58). Patients with venous thrombosis were younger. Venous thrombosis was observed more often in men; arterial thrombosis was more frequent in women. The survival rate was 87% in the venous thrombosis group versus 41% and 38% for arterial embolism and thrombosis, respectively. Compared with the collated historical series, the survival rate was 52% versus 25%. ConclusionsThese results indicate that the prognosis for patients with acute intestinal ischemia is substantially better than previously reported.

A prospective, randomized trial of Unna's boots versus hydroactive dressing in the treatment of venous statis ulcers

In many centers the standard treatment for venous stasis ulcers consists of UB dressings. A new dressing, DuoDERM hydroactive dressing (HD), has recently been used extensively for the treatment of venous stasis ulcers. Because of this trend, a prospective, randomized trial of these two dressings was undertaken. Sixty-nine ulcers (39 HD and 30 UB) were randomized. End points were complete healing and development of complications necessitating cessation of treatment. Time to healing, cost of treatment, and patient convenience were also evaluated. Twenty-one of 30 ulcers (70%) healed with UB therapy compared with 15 of 39 ulcers (38%) treated with HD (p less than 0.01, CST). Life-table healing rates at 15 weeks were 64% for UB compared with 35% for HD (p = 0.01, log rank test). Ten of 39 patients (26%) receiving HD had complications compared with no complications in the UB group (p = 0.004, FET). For those patients whose ulcers healed, there was no significant difference (p = 0.51, STT) in the mean time required for healing or the average weekly cost of dressing materials between the HD group (7.0 weeks at +11.50 per week) and the UB group (8.4 weeks at +12.60 per week). Those patients treated with HD reported a significantly greater level of convenience than those patients with UB (p = 0.004, STT). Although treatment with HD led to better patient acceptance, those patients receiving UB therapy had a significantly greater rate of healing and a significantly lesser incidence of complications than those patients treated with HD.

Hypercoagulable states and lower limb ischemia in young adults

This study prospectively evaluates hypercoagulable states in patients under 51 years of age undergoing lower extremity revascularization for ischemia and assesses early outcome after operation. Twenty patients whose ages range from 23 to 50 years (mean 40.8 years) were identified prospectively who underwent lower extremity revascularization and evaluation of hypercoagulability. Fifteen patients were male (75%), 10 were black (50%), six had hypertension (30%), and four were diabetic (20%). All but two were cigarette smokers (90%). Seven aortoiliac procedures and 13 infrainguinal procedures were performed. Six patients had one or more abnormalities of regulatory proteins (protein S deficiency, four; protein C deficiency, three; presence of lupus-like anticoagulant, three; plasminogen deficiency, two). Eight of 17 patients in whom platelet aggregation profiles were obtained showed increased reactivity (47%). Only 4 of 17 patients (24%) were normal when tested for all parameters. Arterial or graft thrombosis developed in four of the 20 patients within 30 days after operation. Hypercoagulability was found in all four patients whose revascularizations failed. A high incidence of hypercoagulable states was found in patients under 51 years of age with lower limb ischemia requiring revascularization. Hypercoagulability may have contributed to early postoperative thrombosis of the vascular procedure.

The early fate of venous repair after civilian vascular trauma. A clinical, hemodynamic, and venographic assessment.

Repair of major venous injuries of the extremities has been advocated to improve limb salvage rates and to prevent the early and late sequelae of venous interruption. The contribution of venous repair to the surgical outcome remains controversial, however, in part because the fate of venous reconstruction has previously not been well defined. The current study was done to determine the early patency rate of venous repair, to compare the accuracy of various methods used to assess venous patency, and to analyze the relationship between early venous patency and surgical outcome. During a recent 27-month period, 36 patients with major extremity venous injuries were treated by venous reconstruction; 34 patients (94%) had an associated major arterial injury that also required repair. Venous repair was performed in the upper extremity (22%) as well as the lower extremity (78%) using various reconstructive methods, including lateral repair (17%), end-to-end anastomosis (11%), autogenous vein patching (25%), interposition autogenous vein grafting (42%), and panelled autogenous vein grafting (6%). After operation, venous repair patency was evaluated by clinical examination, impedence plethysmography, and Doppler ultrasonography, and contrast venography. There were no perioperative deaths in these 36 patients. The limb salvage rate was 100% and all 34 major arterial repairs were patent at the time of hospital discharge. Venography performed on the seventh postoperative day demonstrated that 14 venous repairs had thrombosed (39%) and that 22 had remained patent (61%). Local venous repair had a significantly lower thrombosis rate (21%) than those requiring interposition vein grafting (59%) (p < 0.03). Compared with venography, the clinical evaluation was 67% accurate in the assessment of venous repair patency, and the noninvasive examination was 53% accurate. In conclusion, a substantial percentage of venous repairs will thrombose in the postoperative period, especially if interposition vein grafting is used. However, in this series limb salvage was not adversely influenced by an unexpectedly high rate of venous repair thrombosis. In addition, clinical evaluation and noninvasive testing did not provide an accurate assessment of venous patency after venous repair.

Recognition of arterial injury in elbow dislocation

The clinical presentation of patients with elbow dislocations was reviewed to identify those factors indicating an increased risk for arterial injury. Sixty-two patients were treated for 63 elbow dislocations between January 1981 and July 1991. Eight patients (13%) sustained a concomitant arterial injury involving the brachial (7) and radial (1) arteries. Three clinical findings, absence of a radial pulse, open dislocation, and presence of systemic injuries, were correlated with arterial injury. A palpable radial pulse was absent in six (75%) patients with an arterial injury but in only two (4%) with normal vessels (p less than 0.0001, chi square). Five (33%) open dislocations had an associated arterial injury, whereas three (6%) arterial injuries occurred in closed dislocations (p less than 0.006, chi square). Systemic injury occurred in five dislocations (63%) with arterial injuries and 14 dislocations (25%) without arterial injury (p less than 0.04, chi square). Multivariate analysis showed that absence of a radial pulse was the only factor that significantly predicted arterial injury (p less than 0.0001). Although most elbow dislocations are not associated with arterial injury, absence of a radial pulse or presence of an open dislocation or both should alert the clinician to the increased possibility of an associated vascular injury.

Dacron inhibition of arterial regenerative activities.

These biocompatibility studies evaluate the effects of Dacron, absorbable polymeric, and compound prostheses containing both elements in various constructions on the migration, proliferation, and functional characteristics of regenerating endothelial and smooth muscle-like cells in the rabbit aorta model. Prosthesis/tissue complexes explanted after 2 weeks to 9 months were studied grossly, photographed, sectioned for light microscopy and scanning and transmission electron microscopy, and assayed for 6-keto-PGE1 alpha contents in inner capsular tissues. Polyglycolic acid, polyglactin 910, or polydioxanone prostheses elicited a transinterstitial migration and proliferation of primitive mesenchymal cells that differentiated into smooth muscle-like myofibroblasts and a surface repopulation of confluent endothelial-like cells paralleling the time course of macrophage-mediated prosthetic dissolution. Even small Dacron components (20%) woven into or surrounding the absorbable polymer significantly inhibited these processes, yielding significantly thinner, less cellular inner capsules with lower 6-keto-PGF1 alpha contents. These studies show the augmentation of clinically efficacious arterial regenerative activities by polymers phagocytosed by macrophages and the inhibition of these activities by Dacron.

Open transmetatarsal amputation in the treatment of severe foot infections

Severe forefoot infections may lead to limb loss, even if addressed aggressively. Infection or gangrene that compromises the plantar skin flap may preclude a standard transmetatarsal or midfoot amputation, thereby culminating in a below-knee amputation. We report a series of forefoot infections with loss of the distal plantar skin. Open or guillotine amputation at the mid-metatarsal level led to a high rate of healing and a durable stump, provided that the level of infection did not extend beyond the metatarsal heads. Wound closure was obtained by wound contracture alone or by use of partial-thickness skin grafting. Rehabilitation was dependable. The association of diabetes mellitus or gangrene did not adversely affect outcome. Open transmetatarsal amputation is a safe surgical option preferable to midfoot or below-knee amputation for the treatment of severe forefoot infection that does not extend proximally beyond the metatarsal heads.

Long-term results of infragenicular bypasses with autogenous vein originating from the distal superficial femoral and popliteal arteries☆

Forty-nine bypasses originating from the distal superficial femoral artery or popliteal artery in 46 patients were reviewed to examine late patency, limb salvage, and factors leading to graft failure. Operations were performed because of tissue loss in 86%, rest pain in 12%, and limiting claudication in 2% of limbs. Proximal anastomosis was from the distal superficial femoral artery in 12% and the popliteal artery in 88%. Distal anastomosis was to the below-knee popliteal artery or proximal tibial vessels in 20% and the distal tibial vessels in 80%. Life-table analysis showed a primary patency rate of 83%, 62%, and 41%, at 1, 3, and 5 years, respectively. The rate of limb salvage at 6 years for all grafts was 69%. Cox proportional hazards analysis determined that stenosis of 20% or greater in the proximal superficial femoral artery before bypass was a significant risk factor for graft failure (p = 0.02) despite the presence of normal intra-arterial pressure at the site of the proximal anastomosis at the time of bypass. Long-term survival in these patients was low, with a 6-year survival rate of only 24%. Infragenicular bypasses originating from the distal superficial femoral artery or the popliteal artery can be performed with patency and limb salvage rates comparable to bypasses originating from the common femoral artery. These bypasses are more likely to fail when performed in the presence of a stenosis 20% or greater in the superficial femoral or popliteal artery proximal to the graft origin.

Autogenous vein graft repair of injured extremity arteries: Early and late results with 134 consecutive patients☆

Autogenous vein tissue is recognized as the preferred material for extremity revascularizations that require the use of a conduit. However, the results after vascular repair of injured extremity arteries with autogenous vein interposition or bypass grafts have not been well defined. This study was done to determine both the early and late patency and limb salvage rates as well as the graft infection rate of autogenous vein repairs of injured extremity arteries. The records of 134 consecutive patients with acute extremity arterial injuries requiring repair with a reversed autogenous vein graft over a recent 5-year period were reviewed. Follow-up graft patency was defined by the presence of a palpable pulse and an extremity Doppler-derived pressure index of greater than or equal to 0.9 distal to the arterial repair. Cumulative patency was assessed by the life-table method. Acute graft thrombosis occurred in two patients, one of whom underwent successful graft thrombectomy. Four patients (3%) required extremity amputation: one patient with a thrombosed vein graft and three patients with patent vein grafts but nonsalvageable limbs as a result of myonecrosis (2) or osteomyelitis (1). No perioperative graft infections occurred. One hundred twenty-eight patients (97%) had an intact extremity and a patent vein graft at the time of hospital discharge. One hundred three patients (80%) were examined at 30 days, and all grafts were patent. Seventy-three patients (57%) were available for follow-up at intervals exceeding 6 months, and 40 patients (31%) were followed-up for periods exceeding 24 months.(ABSTRACT TRUNCATED AT 250 WORDS)

Hip disarticulation: Factors affecting outcome

Hip disarticulation, especially in patients with peripheral vascular disease, has been associated with high morbidity and mortality rates. This report describes patient characteristics that influence the clinical outcome of hip disarticulation. The medical records of all patients undergoing hip disarticulation from 1966 to 1989 were reviewed for surgical indication, perioperative wound complications, and postoperative deaths. Fifty-three patients underwent hip disarticulation for limb ischemia (10), infection (12), infection and ischemia (14), or tumor (17). The overall incidence of wound complications was 60%, and no significant differences were found among the groups. Prior above-knee amputation and urgent/emergent operations were significantly associated with increased wound complications (p less than 0.05). The overall mortality rate was 21%, ranging from 0% (tumor) to 50% (ischemia) and differed significantly among the groups (p less than 0.02). Mortality was significantly associated with urgent/emergent operations (p less than 0.01). Age, diabetes mellitus, and previous inflow procedures did not influence mortality rates. The presence of limb ischemia influenced mortality rates to a greater extent than did infection, and a history of cardiac disease was statistically predictive of death. Wound complications frequently accompanied hip disarticulation, regardless of operative indication, and were significantly increased by urgent/emergent operations and prior above-knee amputation. Hip disarticulation can be performed with low mortality rates in selected patients. Both limb ischemia and infection substantially increase operative mortality rates.