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Biomedical subjects

W R Flinn

Publications and source records attributed to W R Flinn.

At least 73 records · Page 4Linked to original sources
PubMed1985

Infrapopliteal bypass for established gangrene of the forefoot or toes.

This study was undertaken to assess factors affecting limb salvage after femorodistal bypass in patients with established gangrene. From January 1977 through June 1983, 361 patients underwent infrapopliteal bypasses; 58 patients (59 limbs) had forefoot and/or toe gangrene. There were 33 men and 25 women (mean age 67.6 years), and 40 patients (69%) were diabetic. A total of 71 femorodistal bypass procedures were performed in these patients: a single bypass in 49, repeat procedure in eight, and multiple bypasses in two patients. Graft material was autogenous saphenous vein in 22 cases, polytetrafluoroethylene (PTFE) in 39 cases, and a composite graft in 10 procedures. After bypass 50 patients underwent limited toe or forefoot amputation with uncomplicated healing. Limb salvage by life-table analysis was 70% at 1 year, 60% at 3 years, and 28% at 5 years. The graft patency at 3 years was 65% for vein grafts and 30% for PTFE grafts. In the entire series the operative mortality rate was 1.7%. Age, sex, hypertension, or diabetes mellitus did not influence the result of surgery. Similarly, failure of a previous femoropopliteal or tibial graft did not reduce the likelihood of limb salvage. Graft patency, however, is prerequisite for limb salvage, and graft patency can be maintained by thrombectomy or repetitive bypass. The present study suggests that limb salvage is possible in as many as two thirds of limbs with established gangrene. Although saphenous vein remains the graft material of choice, its absence should not preclude attempts at limb salvage. Repetitive grafting did not jeopardize patient safety but contributed significantly to extended limb survival.

Actuarial Analysis↗
PubMed1985

Varicose ulcer of the upper extremity.

Serious complications of local venous hypertension occur rarely in the upper extremity. These are most frequently the result of a dysfunctional arteriovenous fistula and may produce changes indistinguishable from those of chronic lower-extremity venous insufficiency. A combination of arterial and venous contrast imaging is essential for identifying major venous outflow obstruction and for planning appropriate surgical therapy.

Arteries↗
PubMed1984

The efficacy of dextran 40 in preventing early postoperative thrombosis following difficult lower extremity bypass.

In a randomized, multicenter trial the efficacy of intravenous dextran 40 (D-40; Rheomacrodex) in preventing early postoperative thrombosis was tested in the following difficult lower extremity bypasses: (1) femoropopliteal with poor runoff using autologous vein (AV), (2) femoropopliteal using grafts other than AV, (3) single or sequential bypasses to infrapopliteal arteries, and (4) the above-mentioned bypasses with adjunctive procedures that destroy adjacent endothelial surfaces (e.g., thrombectomy and endarterectomy). Five units of D-40 was administered to the experimental group at 75 to 100 ml/hr, two during and immediately after operation and one each 3 days postoperatively. Antiplatelet drugs were withheld until 1 week after surgery. The overall 1-week occlusion rate was 6.9% (5 of 73) with D-40 and 20.5% (17 of 83) for controls, which is statistically significant. Particularly significant was the difference in group 3: 0% (0 of 28) for D-40 and 27.8% (10 of 36) for controls. In the same time period there were no occlusions in group I and only one occlusion each with AV grafts in both D-40 and control groups, 2.6% (1 of 38). When grafts other than AV were used, the occlusion rate was significantly lower at 1 week for D-40, 11.4% (4 of 35), than controls, 35.6% (16 of 45). By 1 month the protective effect of D-40 was partially lost--15.3% (11 of 72) for D-40 and 20.7% (17 of 82) for controls (no statistical significance). Use of antiplatelet drugs during this period had no discernible effect.

Blood Vessel Prosthesis↗
PubMed1984

Sequential changes in coagulation and platelet function following femorotibial bypass.

Twenty-four patients who received no antiplatelet medications and underwent femorotibial bypass grafting (nine vein, 12 polytetrafluoroethylene [PTFE], and three composite PTFE-vein) had serial measurements taken of their platelet function and coagulation. The concentration of collagen required to produce half-maximal platelet aggregation (Kd), the platelet aggregation ratio, antithrombin III, factor VIII-related antigen, and fibrinolytic activity (platelet-rich plasma) was measured preoperatively and 3 and 7 days after surgery. Before surgery eight patients exhibited an increase of platelet reactivity to collagen. Following femorotibial bypass grafting, the mean preoperative Kd of 0.52 +/- 0.37 microgram/ml fell to 0.34 +/- 0.35 microgram/ml on the third postoperative day (P less than 0.001) and returned to 0.41 +/- 0.72 microgram/ml on day 7. Factor VIII-related antigen increased from a mean preoperative value of 248 +/- 29% of normal activity to a mean of 360 +/- 96% on postoperative day 3 (p less than 0.01) and further increased to 428 +/- 78% on day 7 (p less than 0.01). Fourteen patients had antithrombin III measurements taken, and their levels also fell on the third postoperative day (110 +/- 5.7% to 71 +/- 6.5%; p less than 0.001). No significant changes in fibrinolytic activity were noted. Persistent platelet reactivity was found in seven patients beyond the seventh postoperative day. After administration of 325 mg of aspirin, the abnormal platelet reactivity ceased. Increased platelet reactivity to collagen, factor VIII-related antigen, and a decrease in the antithrombin III level are indicative of a hypercoagulable state in these patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Antigens↗
PubMed1984

Composite sequential grafts in severe ischemia: a comparative study.

From October 1978 to June 1983, 64 sequential bypass grafts were performed in 59 patients with limb-threatening ischemia. These patients were classified into three study groups as follows: reversed saphenous vein graft alone (12), composite sequential (proximal polytetrafluoroethylene [PTFE] and distal vein) graft (30), and PTFE graft in entirety (22). Graft patency was confirmed in all cases by serial Doppler ankle pressure measurements or by angiography. Cumulative life-table patency rates were then compared over a period of 27 months. The patency rates for composite sequential grafts using a distal short segment of vein were statistically indistinguishable from those for bypasses performed entirely with saphenous vein. These yielded a patency rate of 80% at 1 and 2 years. In contrast, the 1- and 2-year patency rates of the PTFE sequential grafts were 52% and 47%, respectively (p less than 0.05). Composite sequential bypasses using an otherwise inadequate segment of saphenous vein are a sound alternative revascularization procedure, with a patency rate comparable to that of reversed saphenous vein bypasses.

Adult↗
PubMed1984

Antithrombin III deficiency as a reflection of dynamic protein metabolism in patients undergoing vascular reconstruction.

Antithrombin III (AT-III) deficiency has been associated with increased risk of venous and arterial thromboses and arterial graft failure. Deficiency of this circulating glycoprotein may be congenital; however, acquired deficiencies may develop in protein-losing or protein-wasting states. In the present study, AT-III levels of 108 patients undergoing vascular surgical procedures were determined preoperatively and at intervals (third, fifth, and seventh days) postoperatively. The mean AT-III level was then compared to the patient's protein status. The effect of reduced AT-III activity on early graft failure was also noted. A low preoperative AT-III level (less than 80%) was found in 16.3% of the patients studied. Among 83 patients with serum albumin levels greater than 3.0 gm/dl or transferrin levels greater than 180 mg/dl, reduced AT-III activity was present in only 10 (12%). In contrast, when serum albumin levels were less than 3.0 gm/dl, AT-III deficiency was found in 12 of 25 patients (48%) (p less than 0.01). Early thrombosis of a femorodistal graft occurred in 5 of 15 patients (33%) with reduced AT-III levels. When AT-III levels were normal, early bypass failure occurred in only 9 of 67 grafts (13.4%). However, this difference was not statistically significant. An additional 15 patients had sequential pre- and postoperative measurements (up to 3 weeks) of serum protein and AT-III levels to illustrate the relationship between the dynamics of protein metabolism and AT-III levels. There was a clear temporal relationship between albumin, transferrin, and AT-III levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1983

Modified technique of obturator bypass in failed or infected grafts.

The obturator bypass graft operation can be performed in a moderately simplified manner by a technique that allows extension of indications for the procedure beyond situations in which sepsis is present in the groin. Long-term analysis of the results of the cases available for study indicates that the procedure may very well be a permanent reconstruction, and that graft failure results from graft infection or insufficient distal runoff, as in other distal revascularization procedures. No significant change in ankle pressure is noted when the hip is placed in maximum flexion position.

Aged↗
PubMed1983

The use of operative prebypass arteriography and Doppler ultrasound recordings to select patients for extended femoro-distal bypass.

Of 113 preoperative arteriograms analyzed, 46 (40%) were unsatisfactory to determine operability for femoral-distal bypass. In 23 of these 46 arteriograms, there was complete nonvisualization of calf vessels (Group A) and in the remaining 23, there was limited visualization (Group B). Both prebypass, on-table operative arteriography and Doppler ultrasound recordings were helpful in predicting the best available artery for bypass in all but one patient (4%) in Group A. In Group B, 7 of 23 patients had the site of distal anastomosis altered after prebypass, ontable arteriography. There was no statistical difference in the patency rates of grafts in patients with inadequate visualization (Groups A and B) and those with adequate visualization (67 patients, Group C). Prebypass, on-table operative arteriography, supplemented by preoperative Doppler ultrasound recordings, helps to extend operability and to avoid unnecessary amputation.

Angiography↗
PubMed1983

Intimal hyperplasia and neointima: An ultrastructural analysis of thrombosed grafts in humans.

The distal anastomoses of thrombosed saphenous vein (11), bovine (4), Dacron (7), and polytetrafluoroethylene (PTFE) (27) grafts removed en bloc during reoperation or amputation were studied with light microscopy, scanning electron microscopy, and transmission electron microscopy. Analysis of the ultrastructures of the distal anastomostic regions was done to characterize morphogenesis of intimal hyperplasia and neointimal proliferation. Complete reendothelialization occurred in all vein grafts. In bovine heterografts, there were isolated areas of endothelia. Thrombosed PTFE grafts were lined with gelatinous, proteinaceous material with no consistent organized cellular pattern. In contrast, laminated fibrous tissue produced by fibroblasts lined the Dacron grafts. Intimal hyperplasia was found in 6 of 11 vein grafts and in all prosthetic grafts examined. Regardless of the type of graft used, intimal hyperplasia was found predominantly at the heel of the graft and on the floor of the artery. Beneath the endothelia, collagenous ground substance and myofibroblasts mixed with smooth muscle cells were seen, characterized by pyknotic nuclei, reduced cytoplasm/nuclei ratio, and loss of cytoplasmic organelles. Endothelialization occurred exclusively in vein grafts. Prosthetic grafts lacked endothelia, with the neointima consisting of fibroblasts and fibrous matrix. In intimal hyperplasia, two forms of smooth muscle cell pathomorphogenesis were recognized. Formation of myofibroblasts induced medial fibroplasia, whereas degeneration of muscle cells progressed to medial necrosis. Smooth muscle cells seem to play a role not previously recognized in the pathogenesis of graft failure.

Bioprosthesis↗
PubMed1983

Use of a temporary shunt for renal transplant protection during aortic aneurysm repair.

Broader indications for renal transplantation and improved allograft survival suggest that aortic aneurysms will be encountered more commonly in kidney transplant recipients. This report describes the use of a temporary heparin-bonded shunt placed from the proximal abdominal aorta to the femoral artery for perfusion of a renal allograft during simultaneous repair of an aortic aneurysm and correction of transplant renal artery stenosis. Renal function was satisfactorily maintained intraoperatively and has continued to be excellent during 2 1/2 years of follow-up. Methods of renal transplant protection during aortic reconstruction are reviewed, and principles of temporary shunting for allograft protection are proposed.

Aorta, Abdominal↗
PubMed1983

Hemodynamic assessment of venous problems.

Objective assessment of venous function based on venous refilling time recorded by photoplethysmography (PPG) was done in 89 patients with postphlebitic syndrome (47), primary varicose veins (29), and after an episode of acute deep vein thrombosis (13). Limbs with symptomatic postphlebitic changes had a shortened venous refilling time of 15.6 +/- 11 seconds (normal greater than 20 seconds). When venographic findings (ascending and descending) in 47 patients with postphlebitic syndrome were analyzed, it was noted that femoral valve incompetence demonstrated by descending venography was a common finding (81%), even in asymptomatic limbs (85%). Venous refilling time bore no relationship to the degree of femoral venous valve reflux. However, if there were associated diseased deep veins with incompetent perforating veins, the venous refilling time was much shorter (14 +/- 4 seconds) than in limbs without calf perforating veins (27 +/- 11.9 seconds, P less than 0.05). A tourniquet was used to impede saphenous flow, and changes in refilling time were recorded in 34 limbs with varicosities of the long saphenous vein. Refilling time normalized after tourniquet application in 31 limbs (14.43 +/- 4.34 to 30.64 +/- 11.9 seconds), and all patients underwent vein stripping. Postoperative recording confirmed the improvement in venous refilling time (29.52 +/- 27.8 seconds, P less than 0.05). Thirteen patients with acute deep vein thrombosis had serial PPG tests during a follow-up period of 27 months (mean 15.8 months). Seven had initial abnormal PPG results and persistently abnormal readings, and all developed postphlebitic changes. Venous refilling time is an useful test to determine the hemodynamic significance of femoral venous valve incompetence and to assess the effect of vein stripping on varicose veins. In acute deep vein thrombosis, follow-up study may help to identify patients at risk for development of postphlebitic changes.

Femoral Vein↗
PubMed1983

Correlation of immune and nutritional status with wound complications in patients undergoing vascular operations.

The acquired failure of host immunocompetence that may result from significant protein and caloric malnutrition has been associated with an increased incidence of septic complications in patients undergoing operation. Wound infection in patients undergoing vascular surgical procedures may lead to exposure or contamination of a vascular graft, with the subsequent risk of hemorrhage, limb loss, or death. The present study was undertaken to correlate the immune and nutritional status of patients undergoing vascular surgical procedures with the development of significant wound complications. Seventy-nine patients undergoing a variety of vascular operations were subjected to comprehensive nutritional assessment, including anthropometric measurements (height, weight, midarm circumference, triceps skin fold), serologic testing (albumin, transferrin, lymphocyte count, serum zinc), cutaneous assessment of delayed hypersensitivity (anergy battery), and neutrophil functional analysis. After operation the patients were observed for the development of delayed wound healing or wound infection. Statistical analysis of measured variables was performed to identify immune and nutritional markers with prognostic value. Patients with serum albumin levels above 3 gm/dl were much more likely to have uncomplicated wound healing (P less than 0.001). Similarly, patients with serum transferrin levels above 150 mg/dl had significantly fewer wound problems (P less than 0.01). Only 29% of patients with cutaneous anergy had normal wound healing, while 56% of those with intact cutaneous reactivity healed primarily; this difference, however, was not statistically significant. Diabetics in this series were more likely to develop wound problems (P less than 0.05). Anthropometric measurements provided no predictive information regarding the likelihood of uncomplicated healing. Similarly, measurement of total lymphocyte count and serum zinc yielded no significant prognostic information. The urgent nature of many vascular surgical procedures may preclude preoperative immune and nutritional assessment; however, the outcome of these procedures may ultimately depend upon intact host defense. The contribution of protein and caloric malnutrition to immunocompromise can be easily assessed in these patients. The detection and subsequent reversal of immunoincompetence through the use of enteral or parenteral alimentation should provide a significant reduction in operative morbidity and mortality.

Aged↗
PubMed1982

Deep vein thrombosis in spinal cord injury: effect of prophylaxis with calf compression, aspirin, and dipyridamole.

Twenty-eight consecutive patients with acute spinal cord injury were randomised to one of two regimens for the prevention of deep vein thrombosis (DVT): external pneumatic calf compression (EPCC, 15), or EPCC combined with aspirin, 300 mg bid, and dipyridamole, 75 mg tid (ASA/dip, 13). DVT, detected by the 125I-fibrinogen test and impedence plethysmography, was confirmed by contrast venography. The incidence of DVT in the total group was 33 per cent, significantly less than the 78 per cent observed in 37 untreated patients studied previously (p less than 0.001). DVT developed in six of 15 patients receiving only EPCC, and three of 12 on ASA/dip as well as EPCC (p less than 0.1). The untreated patients studied earlier had significantly increased circulating platelet aggregates, increased platelet affinity for collagen, and elevated factor VIII activities, which generally coincided with the development of DVT (usually 7-9 days after injury). Prophylaxis partially prevented these coagulation abnormalities and delayed the onset of thrombosis. While the differences in the haemostatic parameters between those not treated with ASA/dip and those receiving these agents were not statistically significant (except for the platelet-collagen affinity), there was a trend toward less elevated values in the drug-treated patients. We conclude that spinal cord injury patients are at extreme risk for DVT, and have abnormal platelet and factor VIII activities. Prophylaxis with EPCC significantly and safely reduces the risk of DVT in these patients.

Aspirin↗