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Biomedical subjects

W S Moore

Publications and source records attributed to W S Moore.

At least 145 records · Page 8Linked to original sources
PubMed1988

Patency and intimal hyperplasia: the effect of aspirin on small arterial anastomosis.

This experiment evaluated the effect of aspirin (ASA) on the patency and development of intimal hyperplasia in autologous, small caliber, arterial end-to-side anastomosis. Twenty-eight adult female rabbits had their distal left external iliac artery transposed and anastomosed to the right proximal external iliac artery. Fourteen rabbits received ASA 40 mg by gavage twice in the 24 hours preceding the operation and 5 times a week postoperatively (experimental) and 14 rabbits received no ASA therapy (control). Plasma salicylate levels range from 25 to 36 micrograms per milliliter in experimental animals. Patency of the reconstruction was assessed by Doppler examination each month, confirmed by autopsy and calculated by life table analysis. Five cross sections of each patent anastomosis harvested at six and nine months were examined by light microscopy. A total of seven thromboses occurred in the control group versus two occlusions in the experimental group. Four of the thromboses in the control group occurred less than seven days after the reconstruction, whereas no such events occurred in the experimental group. Patency by actuarial methods at nine months was 45.5% versus 81.8% (p less than .05) in control and experimental groups, respectively. This improvement occurred in spite of similar values for intimal thickness and lumen-to-basement membrane ratios in both control and experimental groups. We conclude that aspirin significantly improves the nine month patency rate of small autologous end-to-side anastomosis, and its effect is most noticeable in the early postoperative period.(ABSTRACT TRUNCATED AT 250 WORDS)

Anastomosis, Surgical↗
PubMed1988

Inflow failure of grafts originating in the axillary artery.

During the last three years we identified three distinct entities which compromised inflow and led to thrombosis of axillofemoral or axillopopliteal grafts. The first patient had recurrent thrombosis of a right axillopopliteal graft. Five thromboses were treated with thrombectomy and distal revisions; the last thrombosis was treated with simple thrombectomy because the patient had right thoracic outlet axillosubclavian artery compression in his usual sleeping posture. Conservative posture modification resulted in continued patency for two years until the patient's death. Stenosis of the subclavian or innominate artery accounted for multiple failures in three other patients. In one no significant preoperative upper extremity pressure difference was seen, whereas differences were noted with an open graft, suggesting a vascular steal at rest. In the second patient, preoperative balloon dilatation of an innominate lesion appeared successful, but the lesion recurred six months later with hemodynamic graft failure and exercise-induced vascular steal. The third patient had a significant kink of the axillary artery with eventual graft thrombosis secondary to "pulling" from the extraanatomic graft. We conclude that pre-and postoperative noninvasive testing, exclusion of thoracic outlet compression, and avoidance of a "pulled down" proximal anastomosis are important in preventing inflow failures of grafts originating from the axillary artery.

Aged↗
PubMed1988

Removal of focal atheromatous lesions by angioscopically guided high-speed rotary atherectomy. Preliminary experimental observations.

A new high-speed rotary atherectomy device, inserted over a guide wire and directed with an angioscope, offers the potential of restoring patency of outflow vessels by "boring out" the atheromatous lesion of the orifices of runoff vessels. The device was tested on 68 cadaver arteries with atheromatous lesions involving the superficial femoral, popliteal, and tibial arteries. This was performed with either free segments or in situ with the device placed through a popliteal arteriotomy. The gross results of rotary atherectomy were assessed by angioscopy, angiography, or both. The luminal surfaces were studied with scanning electron microscopy and transverse sections of vessels were studied with light microscopy. The pulverized atheroma, in colloidal suspension, was analyzed for particle size by Coulter counter. The effect of a colloidal suspension of atheromatous particles on distal capillary circulation was measured in animal experiments. Obstructive lesions were successfully removed in 36 of 37 stenotic arteries (97%) and 18 of 31 completely occluded arteries (58%), an overall efficacy of 54 of 68 (79%). In successfully atherectomized arteries, angioscopy and angiography demonstrated a widely patent, smooth, polished surface. Light microscopy demonstrated removal of the diseased intima with maintenance of the outer media and adventitia. The pulverized atheroma particles were generally smaller than red blood cells and injection of the colloidal atheroma into canine femoral arteries failed to produce local tissue injury. We conclude that in the human cadaver this atherectomy device effectively enlarges and recanalizes obstructed superficial femoral, popliteal, and tibial arteries.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiography↗
PubMed1988

Postoperative thrombotic complications in patients with lupus anticoagulant: increased risk after vascular procedures.

This study retrospectively analyzes the nature of postoperative thrombotic complications in patients with the lupus anticoagulant. Tests in 84 patients were positive for the presence of antiphospholipid antibodies by an abnormal rabbit brain neutralization procedure, positive for the presence of anticardiolipin antibodies, or both. Twenty-three of these 84 patients had 51 separate surgical procedures, 18 vascular and 33 nonvascular. Four patients had 11 postoperative thrombotic complications (during same hospitalization), involving peripheral arteries in nine cases, vein in one, and coronary artery in one. Nine of the 18 vascular procedures were complicated by thrombosis, whereas only two of the 33 nonvascular procedures were complicated by thrombosis (p less than 0.025). Three of the seven patients who had a vascular procedure suffered multiple postoperative thrombotic complications, and ultimately all three required an amputation. At the time of these thrombotic complications, all three patients had not received any perioperative medications (anticoagulants, antiplatelet agents, and/or corticosteroids). Further analysis revealed a correlation between preoperative medications and the lack of postoperative complications, suggesting that perioperative corticosteroids, anticoagulants, and/or antiplatelet agents may protect against postoperative thrombosis. We conclude that patients with the lupus anticoagulant having surgical procedures carry a significant risk of postoperative thrombotic complications, particularly after vascular procedures.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Is the preferential use of polytetrafluoroethylene grafts for femoropopliteal bypass justified?

The objective of this review is to analyze the long-term results of femoropopliteal bypass done preferentially with polytetrafluoroethylene (PTFE) grafts in patients who presumably had saphenous vein available. The results are analyzed according to preoperative variables in an attempt to determine those instances in which PTFE grafts may be preferred for the first reconstruction and to identify those patients who benefited from vein preservation. From 1979 to 1985, 146 femoropopliteal bypass operations were performed in 120 patients with 6 mm PTFE grafts used preferentially. The results with follow-up at 5 years are analyzed by actuarial methods. The patency rate at hospital discharge was 100%. The overall primary patency rate at 5 years was 57%. Reconstructions above the knee (101) and below the knee (45) had significantly different 5-year patency rates (63% vs 44%, p less than 0.03). Sixty-two reconstructions done to alleviate disabling claudication had a 5-year primary patency rate of 69% and no amputations. Eighty-one reconstructions were done to treat critical ischemia with a 5-year patency rate of 49% and a 5-year foot salvage rate of 73%. When secondary operations were required to treat graft failures, the 4-year cumulative patency rate of the secondary reconstruction was 18% when performed with a prosthetic graft, in contrast to 70% when performed with the spared saphenous vein. We conclude that femoropopliteal reconstruction with PTFE grafts is a reasonable alternative for older patients with disabling claudication. Patients with critical ischemia will likely benefit from preservation of the vein with initial femoropopliteal reconstruction done with PTFE. Staged infrainguinal revascularization for foot salvage may improve present results. In this regard the sequence PTFE-then-vein carries a higher predicted patency rate than the sequence vein-then-PTFE.

Actuarial Analysis↗
PubMed1988

Can clinical evaluation and noninvasive testing substitute for arteriography in the evaluation of carotid artery disease?

The objective of this study was to prospectively assess the value of combining clinical assessment and noninvasive testing in predicting the spectrum of carotid bifurcation pathology, as subsequently proven by arteriography, in order to determine the safety and accuracy of performing carotid endarterectomy without angiography. A panel of eight specialists representing vascular surgery, neurology, and neurosurgery were presented with the history, physical findings, and noninvasive test results (GEE-OPG and duplex scan) of 85 patients. They were asked to make an anatomic prediction of the status of each carotid artery (170 arteries) as to whether the bifurcation was normal, ulcerated, had a hemodynamically significant stenosis, or was occluded. The predictions were then prospectively evaluated and correlated with angiographic findings; 159 of 170 (93.5%) carotid arteries were accurately characterized; 73 of 80 (91%) symptomatic carotid arteries and 86 of 90 (95.5%) asymptomatic arteries were correctly characterized; 61 of 61 (100%) stenoses of hemodynamic significance, nine of 14 (64.3%) ulcerations without stenosis, and 18 of 18 (100%) of total occlusions were accurately identified by the panel. Twenty-nine patients have subsequently had 32 carotid endarterectomies without angiography, and the predicted lesion was confirmed at the time of exploration. The combination of clinical assessment and noninvasive testing, particularly duplex scanning, when performed in a laboratory with validated accuracy may with defined qualification be safely used as a substitute for contrast angiography.

Aged↗
PubMed1988

Factors affecting the patency of infrainguinal bypass.

Two hundred forty-nine well-characterized difficult distal bypasses, entered into a multicenter dextran 40 trial, were reevaluated after 3 years. Seventy in situ (IS) vein grafts, 49 reversed saphenous (RS) vein grafts, 60 polytetrafluoroethylene (PTFE) grafts, and 70 umbilical vein (UV) grafts were used. Primary and secondary patency rates at 3 years were, respectively, 84% and 90% for IS, 66% and 73% for RS, 35% and 48% for PTFE, and 24% and 32% for UV. Subgroup analysis according to the site of distal anastomosis showed no significant differences in primary patency among these grafts at the above-knee level but significant differences between both vein grafts (IS and RV) and the others (PTFE and UV) below the knee (78% vs 31%, respectively). This difference increased at the tibial level (78% vs 10%) but there was also a significant difference between IS grafts (88%) and RS grafts (63%) at this level. Hazard functional analysis showed all grafts except IS grafts begin to fail at an increasing rate again by 24 months. Although overall results appeared to favor PTFE over UV, 62% of PTFE vs 16% of UV terminated at the above-knee level and the patency results of these two grafts were not significantly different at any level. The only other factor than graft type and distal anastomotic site that consistently correlated with late patency was tobacco use. Diabetic patients actually fared significantly better than nondiabetic patients, presumably because of the higher use of IS grafts and lower use of tobacco. The choice of graft overshadows all other factors affecting patency and its influence is magnified with more distal terminal anastomosis.

Anastomosis, Surgical↗
PubMed1988

Computed electroencephalographic topographic brain mapping. A new and accurate monitor of cerebral circulation and function for patients having carotid endarterectomy.

To determine the usefulness of computed electroencephalographic (EEG) topographic (CET) brain mapping to monitor neurologic function during carotid endarterectomy (CEA), 46 consecutive patients having CEA were monitored preoperatively, intraoperatively, and immediately postoperatively by CET brain mapping and simultaneous 16-lead EEG. Preoperative studies revealed that 7 of 16 asymptomatic patients, 5 of 11 patients with amaurosis fugax, and 8 of 12 patients with transient ischemic attacks (TIAs) had abnormal CET brain mapping suggestive of previous subclinical stroke. EEG was abnormal in only 8 of the 20 patients with abnormal CET brain mapping. Intraoperatively during carotid cross-clamping, ischemic changes were seen on CET brain mapping in 23 patients whereas EEG detected these changes in only 13 patients. Ischemic changes detected by intraoperative CET brain mapping were more likely to occur in patients with previous stroke (six of seven) than in patients without previous stroke (17 of 39), p less than 0.05. Patients with changes detected by intraoperative CET brain mapping had an average carotid back-pressure of 38 mm Hg, in contrast to 57 mm Hg for patients without CET brain mapping changes, p less than 0.05. After endarterectomy, CET brain mapping revealed new ischemic changes in one patient who awoke with a mild stroke and in one patient who had TIAs and amaurosis fugax within 6 hours of surgery. We conclude that CET brain mapping is a sensitive, accurate, and useful noninvasive monitor of cerebral circulation and function for patients having CEA.(ABSTRACT TRUNCATED AT 250 WORDS)

Blindness↗
PubMed1987

Effect of endarterectomy on arterial fibrinolytic activator activity.

Although endarterectomy leaves a raw subintimal surface, thrombotic complications are rare. This may be the result of activation of the fibrinolytic system. Fibrinolytic activator activity (FAA) was studied after intimectomy of 3-cm segments of carotid artery in dogs. Endarterectomized segments and contralateral control arteries were resected immediately following intimectomy (group 1) and after blood flow restoration of ten minutes, three hours, and 24 hours (groups 2, 3, and 4, respectively). Areas of fibrinolysis around punch biopsy specimens from each endarterectomy segment and from the control artery were measured. Fibrinolytic activator activity, the ratio of the areas in endartectomized segments to control arteries, was reduced in groups 1 through 3 (mean, 60.7%, 70.1%, and 79.7%, respectively) and was normal in group 4 (94.3%). We conclude that canine FAA is significantly depressed at the endarterectomy site initially but returns to normal at 24 hours. The source of FAA may be synthesis by subintimal structures or delivery by the circulation. During this period of increased thrombogenicity, use of antiplatelet or anticoagulant therapy would be justified.

Animals↗
PubMed1987

Incidence and mechanism of post-carotid endarterectomy hypertension.

Hypertension following carotid endarterectomy occurs frequently but is poorly understood. Its occurrence has been correlated with an increased incidence of neurologic complication. We identified those factors that correlate with an increased incidence of post-carotid endarterectomy hypertension. The records of 100 patients who underwent carotid endarterectomy at UCLA Medical Center from November 1981 to September 1983 were examined. One hundred fifty variables were surveyed to determine those factors associated with this problem. Fifty-eight percent of the study patients developed post-carotid endarterectomy hypertension (an increase in systolic blood pressure greater than 35 mm Hg over baseline, and/or blood pressure requiring treatment with sodium nitroprusside). Of patients who developed this problem, 93% had diabetes mellitus, 75% received isoflurane anesthesia, 71% had peripheral vascular occlusive disease, 71% underwent ipsilateral transient ischemic attacks, and 65% had high-grade ipsilateral carotid stenosis. These variables have in common the loss of or interference with cerebral autoregulation. Central dysautoregulation may set the stage for a positive feedback mechanism that results in increased blood pressure. Anesthetic agents that do not interfere with cerebral autoregulation may reduce the incidence of this complication, and an aggressive treatment program may prevent neurologic complications.

Adult↗
PubMed1987

Perigraft seroma: clinical, histologic, and serologic correlates.

A 14 year retrospective study of perigraft seroma, defined as an enlarging sterile fluid collection at the site of a prosthetic graft, revealed well-documented cases in 5 of 118 extraanatomical bypasses (4.2 percent), 3 of 248 aortic reconstructive procedures (1.2 percent), and 1 of 395 femoropopliteal bypasses (0.3 percent). These nine cases involved four polytetrafluoroethylene and five Dacron grafts. There were five graft thromboses, one instance of limb loss, two graft infections, two deaths, and 13 separate surgical procedures related to the perigraft seroma. Histologic studies revealed a fibrous pseudomembrane lining the perigraft seroma wall and immature fibroblasts lining the graft. Sera from three patients with perigraft seroma, five patients with well-incorporated prosthetic grafts, and three healthy volunteer subjects were tested for in vitro evidence of fibroblast inhibition against fibroblast tissue cultures derived from the pseudomembrane of a perigraft seroma. Control fetal calf serum, sera from all three healthy subjects, and sera from all five patients with well-incorporated grafts allowed fibroblast proliferation. In contrast, sera from all three patients with perigraft seroma inhibited fibroblast growth. Furthermore, sera collected 1, 2, and 3 months after graft removal from one patient and serum collected 3 months after spontaneous resolution of a perigraft seroma from another patient failed to inhibit fibroblasts. We have concluded that patients with perigraft seroma have a high rate of graft and limb loss and require multiple reoperations. The pathogenesis of perigraft seroma appears to involve a humoral fibroblast inhibitor which prevents maturation and proliferation of perigraft fibroblasts, leading to poor graft incorporation. The decrease of inhibition below detectable levels after graft removal or spontaneous resolution of the perigraft seroma suggests that the graft may induce host production of the inhibitor. Effective therapy of perigraft seroma may include fibroblast modulation, removal of the inciting graft, or both.

Blood Vessel Prosthesis↗
PubMed1987

Primary anastomotic bonding in polytetrafluoroethylene grafts?

Previous studies have demonstrated that standard knitted and woven fabric grafts are forever dependent on the suture material for anastomotic tensile strength. Clinical experience with polytetrafluoroethylene (PTFE) and double velour knitted grafts have shown that there is extensive fibrous capsular bonding between the graft and the surrounding tissues. This would lead to increased anastomotic tensile strength. To test this theory, 34 mongrel dogs underwent replacement of their infrarenal aortas with grafts made of PTFE (10 dogs), of double velour knitted Dacron (DVD, 11 dogs), of single velour knitted Dacron (SVD, 5 dogs), and of woven Dacron (WD, 8 dogs). One anastomosis was constructed with 5-0 Prolene and the opposite anastomosis was constructed with 5-0 Dexon (average absorption time, 21 days). In five grafts each of PTFE and DVD, as well as in all eight WD grafts, the midgraft was divided and resutured with 5-0 Dexon. All grafts were harvested together with adjacent proximal and distal aorta between 3 and 10 months from the time of implantation. The tensile strength of each anastomosis was measured with a tensiometer. The mean graft-to-artery (absorbable suture) anastomotic tensile strength, in pounds, for PTFE (14.3) and DVD (12.6) was significantly higher than that for SVD (6.9) or WD (7.2) (p less than 0.003). Graft-to-graft anastomotic tensile strength for PTFE (mean 17.3) was significantly better than that for DVD (mean 9.0; p less than 0.03) or WD (mean 7.9; p less than 0.001). Analysis of anastomotic tensile strength as a function of time revealed continued increase in PTFE in contrast to a slow decline with time in DVD.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Relationship of extracranial carotid occlusive disease and central retinal artery occlusion.

Central retinal artery occlusion usually results in blindness. The association between central retinal artery occlusion and extracranial carotid disease has not been clearly delineated. We reviewed the case reports of 62 patients with central retinal artery occlusion, 25 of whom underwent carotid angiography as part of the diagnostic evaluation. Fourteen of the 25 (56 percent) were found to have ipsilateral extracranial carotid disease. These patients did not generally have carotid bruits and had normal noninvasive carotid tests. Ten patients underwent ipsilateral carotid endarterectomy; these patients had either embologenic ulcerated plaque or tight stenosis of the carotid artery. There were 11 patients who showed no abnormalities on angiography. Thirteen patients who did not undergo angiography showed clinical evidence of etiologic factors, including vasculitis, an embolism of cardiac origin, and trauma. The remaining 24 patients had no diagnostic workup. Follow-up data were available in six of those patients who underwent carotid endarterectomy for a mean of 34 months; no strokes were reported. In conclusion, over half of patients with central retinal artery occlusion who undergo carotid angiography will have a carotid lesion on the ipsilateral side. This suggests that central retinal artery occlusion is a significant marker for extracranial carotid disease and should be an indication for complete carotid evaluation.

Adolescent↗
PubMed1986

Development of a "leak-proof," knitted Dacron vascular prosthesis.

We have developed a technique to render knitted Dacron prostheses totally impervious to blood leak by impregnating the cloth with collagen. These grafts were prepared by the manufacturer, sterilized, and have an indefinite shelf life. The objective of this study was to determine whether collagen impregnation has a deleterious effect on surface thrombogenicity and graft healing. The infrarenal aortas of 30 mongrel dogs were replaced with 6 cm X 6 mm Dacron grafts (15 collagen-impregnated and 15 control). The collagen-impregnated prostheses were visibly indistinguishable from the control. After blood flow was restored, no interstitial bleeding occurred in the collagen grafts, in contrast to the control grafts that initially leaked profusely. When they recovered, the dogs were divided into three groups: group I (five collagen, five control), group II (five collagen, four control), and group III (five collagen, three control). The grafts were harvested at 3, 6, and 9 months, respectively. Retroperitoneal healing response, capsular thickness and adherence, completeness of neointimal healing, surface fibrinolytic activator activity, and sections taken for light and scanning electron microscopy were studied and compared in a blinded fashion. In a separate set of experiments, experimental and control grafts were compared for in vivo surface thrombogenicity. The healing data were identical in the experimental and control prostheses in all parameters. Of particular interest was that initial capsule adherence was better and surface thrombogenicity less in the collagen-impregnated prosthesis. We conclude that collagen impregnation of a knitted Dacron prosthesis has no deleterious effect for the term of observation of this experiment.

Animals↗