James J. Schuler

Aspirin response and failure in cerebral infarction

Background and Purpose The purpose of this study was to assess the biological effect of aspirin as measured by the inhibition of platelet aggregation in patients taking aspirin for stroke prevention and in patients with acute stroke. Methods We administered increasing doses of aspirin (325,650,975, and 1,300 mg daily) to 113 patients for stroke prevention and measured the inhibition of platelet aggregation in these patients and in 33 patients with acute stroke taking aspirin before stroke onset. Results Eighty-five patients on ≤325 and six on ≥650 mg aspirin daily had complete inhibition of platelet aggregation. Increase of the dose by 325 mg in nine of the 22 patients with partial inhibition of platelet aggregation produced complete inhibition in five patients at 650 mg and in one at 975 mg. At 1,300 mg, three patients still had only partial inhibition of platelet aggregation (aspirin resistance). Of the 33 inpatients with acute stroke, 24 had platelet aggregation studies done before further administration of aspirin. Of these, 19 had complete inhibition of platelet aggregation and three had partial inhibition, with production of complete inhibition of platelet aggregation at dose escalation; one patient was aspirin-resistant and the other noncompliant. Conclusions How the inhibition of platelet aggregation relates to stroke prevention remains unclear. The ability of aspirin and the dose required to inhibit platelet aggregation may depend upon the individual.

Ultrasonography of Blood During Stasis and Coagulation

A series of in vitro and animal experiments were performed to determine ultrasonic features of blood during stasis and coagulation. Liquid whole blood became echogenic within a few seconds to 3 minutes following the onset of stasis. This occurred in citrated human blood allowed to stand and in occluded segments of vena cava and aorta of dogs. Mechanical agitation of the blood in stasis caused a disappearance of echoes. This echogenicity occurred with gray-scale and real-time ultrasonography using 7.5-mHz transducers, but was not observed with 3.5-mHz transducer used in real-time scanning. Whole blood clot was echogenic both with 7.5- and 3.5-mHz scanning. Fibrin clot was sonolucent. Echogenicity with stasis did not occur with plasma, serum, or packed erythrocytes. The development of echogenicity required the presence of fibrinogen or its products plus erythrocytes. The echogenicity of blood during stasis detectable by high-frequency ultrasonography probably was related to physical layering of blood products. The disappearance of reflective echoes following agitation suggested that the layering could be readily disrupted.

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.

Can carotid duplex scanning supplant arteriography in patients with focal carotid territory symptoms

Previous reports have suggested that duplex ultrasonography might supplant arteriography as a guide to operative decision making in selected patients with cerebrovascular disease. This study was undertaken to test that tenet in patients with focal carotid territory symptoms. Seventy-two patients having independently interpreted arch and selective carotid arteriography and duplex scanning underwent 78 carotid endarterectomies. Operative specimens were analyzed in all cases and used as the standard in evaluating the accuracy of the preoperative studies. All patients had disease found at the time of operation. The sensitivity of duplex scanning was 99% vs. 91% for arteriography (p = 0.06). In seven cases the scan accurately predicted disease in patients with normal arteriograms and in a single case the scan was read as normal in a patient with a smooth minimally stenotic plaque read as an irregular 30% stenosis on arteriography. The accuracy of duplex scanning was markedly superior to arteriography in detecting intimal surface abnormalities (92% vs. 64%, p less than 0.001) and ulceration (90% vs. 54%, p less than 0.001). There was no difference between duplex scan and arteriography (p = 1.0) in predicting a greater or less than 50% stenosis (accuracy, 94% for arteriogram; 92% for duplex scanning). Of the patients with preoperative potentially reversible symptoms, 97% were free of symptoms at a mean follow-up of 9 months after operation. Eighty-nine percent (17 of 19 patients) of patients with concomitant, ipsilateral, intracranial, or intrathoracic cerebrovascular disease were free of symptoms after carotid endarterectomy.

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.

Persistent sciatic artery: Clinical aspects and operative management

Abnormal persistent of the embryonic axial blood supply to the leg, the sciatic artery, is a rare but often clinically important condition. The sciatic artery may vary from a small collateral in the upper thigh to a very large vessel that is the legs sole arterial blood supply. The abnormal artery is prone to aneurysmal dilatation and atherosclerotic occlusion, and different patterns of anatomic development in the sciatic and femoral artery systems pose significant diagnostic and therapeutic problems. Advances in preoperative hemodynamic assessment, arteriography, and vascular surgical technique have improved the results of management of persistent sciatic artery and its complications. The world literature has been reviewed, including one additional case, with emphasis on embryologic development, anatomic variations, and clinical presentation, as well as diagnosis, therapy, and results.

Experience with latrogenic Pediatric Vascular Injuriese: Incidence, Etiology, Management, and Results

During a 32-month period, 79 extremities in 76 children (age 1 day-13 years, mean = 31 months) were evaluated with regard to iatrogenic vascular injuries. Prospectively, 42 children were studied pre- and post-cardiac catherization. Ten of these children sustained vascular injuries (incidence = 24%). Thirty-four additional children were referred because of 35 iatrogenic vascular injuries as a result of transfemoral cardiac catheterization (n = 20), umbilical artery catheterization (n = 10), or recent surgery (n = 5). All 45 injuries were evaluated by lower extemity segmental Doppler pressure measurements in addition to routine physical examination at the time of injury and at frequent follow-up. An ankle/brachial pressure index (ABI) < 0.9 was considered abnormal. Selected children (ABI < 0.9 for >30 days) underwent orthoroentgenograms to assess limb growth. The average ABI immediately following injury was 0.34 +/- 0.33. Thirty-four injuries were treated nonoperatively. Twelve injuries were excluded from further study due to death (n = 7) or being lost to follow-yp (n = 5). A return of ABI to normal was seen from 1 day to 2 years in 93% of children treated with heparin (n = 14) compared to 63% of children who were simply observed (n = 8) (p < 0.10). The initial severity of ischemia did not correlate with the subsequent rate of improvement. Only patients with absent femoral pulses were selected for operative intervention, which consisted of aortic thrombectomy (n = 2), femorofemoral bypass (n = 2), femoral artery patch angioplasty (n = 1), or femoral artery thrombectomy (n = 7) with no mortality. Nine patients had immediate return of a normal ABI after surgery. A delayed return of ABI to normal occurred in the other two. Nine per cent of surgically treated children and 23% of nonsurgically treated children developed leg length discrepancies (0.5–3.0 cm) as a result of ischemia lasting >30 days. Overall, 91% of the children in this series eventually regained normal circulation following injury and no child lost a limb. This study indicates that iatrogenic pediatric vascular injuries are common and can result in significant limb growth impairment. Immediate operative intervention is highly successful when the injury is proximal to the common femoral artery bifurcation and avoids the prolonged ischemia seen with nonoperative therapy. For moral distal occlusions, heparin therapy provides better results than simple observation. Although therapeutic intervention for these injuries is generally successful, a limb length discrepancy rate of 14% mandates that indications for invasive vascular monitoring and diagnostic procedures be strict.

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.

Mortality and limb loss with infected infrainguinal bypass grafts

A recent experience with infrainguinal graft infections was reviewed in an effort to identify factors related to limb loss and mortality. The records of 32 patients who had operative treatment of 33 episodes of infrainguinal graft infection between 1978 and 1985 were reviewed to evaluate the effects of 20 factors possibly affecting outcome. The amputation rate was 79%. Of the 20 factors studied, only the presence of overt limb sepsis was associated with the need for amputation, with 100% of patients having limb sepsis requiring amputation vs. 72% of patients without limb sepsis (p = 0.03). The in-hospital mortality rate was 22%. Eighty-six percent of the deaths were due to ongoing sepsis. Again, a single factor was associated with death. Five of the 12 patients (42%) in whom preservation of axial flow was attempted died in contrast to only 2 of 20 patients (10%) who did not have attempted arterial reconstruction (p = 0.04). Limb salvage did not occur in any of the patients in whom preservation of axial flow was attempted and nine required above-knee amputation. Thirteen of the remaining 20 patients had occluded femoral vessels either because of operative ligation (nine) or previous thrombosis (four). Above-knee amputations healed in all but one of these 13 patients. Determined attempts at increasing limb preservation were associated with no improvement in amputation rate or level and were accompanied by an unacceptably high mortality rate. Aggressive control of sepsis through the early amputation of septic limbs after graft removal may improve survival without further detriment to limb preservation.

Efficacy of prostaglandin E1 in the treatment of lower extremity ischemic ulcers secondary to peripheral vascular occlusive disease *: Results of a prospective randomized, double-blind, multicenter clinical trial

Most previous reports suggesting beneficial effects of prostaglandin E1 (PGE1) have been retrospective and uncontrolled. Therefore, this study was undertaken to assess the efficacy of PGE1 in the treatment of ischemic ulcers in patients with peripheral vascular occlusive disease (PVOD). One hundred twenty patients with one to three ischemic ulcers not healing for 3 weeks with standard care were randomized to receive either PGE1 (20 ng/kg/min) or a placebo for 72 hours through a central venous catheter. Ulcers were measured and photographed, and the rest pain was evaluated before and after infusion and at 1- and 2-month follow-up intervals. Fifty-seven patients with 95 ulcers received PGE1. Seventeen ulcers healed (18%); 22 ulcers decreased in size (23%); 37 ulcers remained unchanged or increased in size (39%); five new ulcers developed during the study (5%); and 14 ulcers had inadequate follow-up (15%). Sixty-three patients with 115 ulcers received a placebo. Nineteen ulcers healed (16%); 38 ulcers decreased in size (33%); 45 ulcers remained unchanged or increased in size (39%); three new ulcers developed during the study (3%); and 10 ulcers had inadequate follow-up (9%). None of the above differences between the drug-treated group and the placebo-treated group was statistically significant. This study did not demonstrate efficacy for intravenously administered PGE1 in the healing of ischemic ulcers in patients with PVOD.