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Biomedical subjects

F W LoGerfo

Publications and source records attributed to F W LoGerfo.

At least 109 records · Page 6Linked to original sources
PubMed1986

Organization of an organ donation network.

The National Organ Donation Network involves numerous organizations and institutions, with the organ procurement agencies playing a key role. Figure 2 depicts the complex structure of the procurement process. There is little consistency in structure among community procurement networks, but there is a strong unified approach to the national sharing of organs and tissues. More regionalization has led to better coordination of all procurement and educational efforts, and the role of the procurement coordinator has evolved into a new health profession.

Canada↗
PubMed1986

Transplant ureteral obstruction masquerading as recurrent rejection episodes: management by percutaneous antegrade balloon dilatation.

We report a 52-year-old male renal transplant recipient who had three "rejection episodes." The first of these responded to conventional antirejection therapy; however, the next two episodes showed incomplete responses to treatment for rejection. At subsequent presentation with deteriorating renal function, ureteral obstruction was evident and was relieved with percutaneous antegrade balloon dilatation with a return of his plasma creatinine to normal. Obstruction of the ureter was a major component in our patient's course given the lack of response to conventional antirejection therapy and the normalization of renal function with relief of the documented ureteral stenosis. This case illustrates that ureteral obstruction can mimic rejection in the renal transplant recipient. Management of ureteral stenosis in transplant patients with percutaneous antegrade balloon dilatation appears to be an effective procedure and can supplant the need for open surgical procedures.

Catheterization↗
PubMed1986

Management of the contused arterial segment.

When a contused arterial segment is found at surgical exploration and interposition graft is required, we propose a method of repair in which the posterior wall is not completely divided. This prevents retraction of the arterial ends and eliminates tension on the anastomosis.

Arteries↗
PubMed1985

Retroperitoneal inflow procedures for iliac occlusive vascular disease.

We reviewed our experience over the past six years with retroperitoneal inflow procedures (aortofemoral and iliofemoral bypass grafts) in high-risk patients with aortoiliac occlusive disease. There were 57 limbs in 40 patients. Twenty percent of the patients were diabetic, 80% were smokers, 40% had heart disease, 54% had hypertension, and 25% had symptomatic chronic obstructive pulmonary disease. The average patient age was 64 years. There was no operative mortality and cumulative patency rate by life-table analysis at four years was 84%. The site of the proximal anastomosis (aorta vs iliac) or the configuration of the graft (unifemoral vs bifemoral) did not influence the patency rate. Retroperitoneal inflow procedures are an excellent alternative in patients who present an unacceptably high risk for standard aortofemoral reconstruction.

Adult↗
PubMed1985

A comprehensive approach to extremity vascular trauma.

A review of our experience with 368 patients with 382 extremity injuries has resulted in a treatment plan resulting in improved patient care and limb survival. A thorough examination of the injured extremity will help diagnose a significant vascular injury in the presence of certain clinical findings, eg, bruit or thrill (100%), signs of acute ischemia (100%), absent pulse (91%), shock (89%), neurologic deficit (78%), and hematoma (55%). Arteriography in proximity injuries has resulted in an abnormal finding in 16% of cases. A total of 165 vascular injuries, including 112 arterial and 53 venous injuries, were repaired using a variety of techniques. In 136 patients undergoing operative intervention, there was no operative mortality and a 1.5% amputation rate.

Adult↗
PubMed1985

Structural details of boundary layer separation in a model human carotid bifurcation under steady and pulsatile flow conditions.

We have used a dye-flow visualization technique to analyze the substructure of flow separation in a plastic model of the human carotid bifurcation under steady and pulsatile flow. Under steady conditions at a physiologic flow split (Q external carotid/Q common carotid = 0.30) and Reynolds number (500), a large region of separated fluid developed along the outside wall of the sinus, opposite the flow divider. Yellow dye injected into the boundary layer upstream from the bifurcation traveled slowly along the wall of the common carotid and entered directly into the separation. Blue dye injected into the central, high-velocity streamlines in the common carotid impacted on the flow divider, then traveled circumferentially and entered the separation. Mixing of these two sources was documented by the appearance of green fluid, which lingered in the region of separation. Pulsatile flow resulted in a smaller region of separation; mixing still occurred. Flow separation at the carotid bifurcation is a site of mixing of fluids previously subjected to prolonged low-shear wall contact and brief high-shear wall contact. Separation is itself a site of low shear, but this study reveals a mechanism whereby low and high shear may act independently or synergistically to explain the link between flow separation and atherogenesis.

Carotid Arteries↗
PubMed1984

A clinical technique for prevention of spasm and preservation of endothelium in saphenous vein grafts.

Spasm and endothelial injury during harvesting of saphenous vein grafts can be prevented by a protocol that involves perivenous infiltration with 37 degrees C papaverine hydrochloride solution prior to skin incision, initial distention of the vein with the same warm papaverine solution, storage of the distended vein graft in a cold papaverine solution, and maintenance of the vein in the distended state throughout the operative procedure. This technique preserves endothelial integrity in human reversed saphenous vein grafts.

Blood Vessel Prosthesis↗
PubMed1983

Evaluation and management of vascular injuries of the extremities.

We reviewed our experience with 315 extremity injuries in 306 patients for the possibility of accurately evaluating the presence of a potential vascular injury. Indications for surgical exploration based on the clinical finding of a bruit and/or thrill, ischemia, absent, pulse, shock, hemorrhage, neurologic deficit, hematoma, and proximity resulted in a rate of positive surgical exploration results of between 20% and 100%. Angiography was performed in 65 patients; 24 angiograms showed vascular injury and 41 did not. Angiography for proximity alone revealed 12% abnormal finding. Operative morbidity in the surgically explored group was 2%. We developed an algorithm for the treatment of these patients.

Adolescent↗
PubMed1983

Downstream anastomotic hyperplasia. A mechanism of failure in Dacron arterial grafts.

The precise location and progression of anastomotic hyperplasia and its possible relationship to flow disturbances was investigated in femoro-femoral Dacron grafts in 28 dogs. In 13 grafts, the outflow from the end-to-side downstream anastomosis was bidirectional (BDO), and in 15 it was unidirectional (UDO) (distally). Grafts were electively removed at intervals of two to 196 days or at the time of thrombosis. Each anastomosis and adjacent artery was perfusion-fixed and sectioned sagittally. The mean sagittal section was projected onto a digitized pad, and the total area of hyperplasia internal to the arterial internal elastic lamina and within the adjacent graft was integrated by computer. The location of the hyperplasia was compared with previously established sites of flow separation and stagnation. The observation was made that hyperplasia is significantly greater at the downstream, as compared with the upstream, anastomosis in both groups (BDO = p less than 0.001 and UDO = p less than 0.001) (analysis of variance for independent groups). Furthermore, this downstream hyperplasia was progressive with time (BDO p less than 0.01) (UDO p less than 0.01); Spearman Rank Correlation. There was no significant increase in the extent of downstream hyperplasia where flow separation was known to be greater (BDO). Five grafts failed (three BDO, two UDO), as a result of complete occlusion of the downstream anastomosis by fibrous hyperplasia. Transmission electron microscopy showed the hyperplasia to consist of collagen-producing smooth muscle cells. Anastomotic hyperplasia is significantly greater at the downstream anastomosis, is progressive with time, and is the primary cause of failure of Dacron arterial grafts in this model. Quantitative analysis of downstream anastomotic hyperplasia may be a valuable measure of the biocompatibility of Dacron grafts.

Animals↗
PubMed1983

Integrity of vein grafts as a function of initial intimal and medial preservation.

An "optimal" technique of vein graft preparation with papaverine and tissue culture was compared with an "injury" technique with 37 degrees C saline storage for 1 hr. Paired interposition cephalic vein grafts were placed in the femoral arteries of dogs. Specimens were taken at the time of implantation, at 3 and 24 hr, and at 7 and 30 days for light, scanning, and transmission electron microscopy. Veins obtained by the injury method showed extensive initial disruption of the endothelium and platelet and white cell adhesion at 3 and 24 hr. At 7 days the endothelium was restored, but there was marked inflammation and neovascularization of the media. At 30 days this had resolved; however, the smooth muscle cells appeared modulated (increase in relative numbers of metabolic organelles with contractile apparatus disassembly). Extracellular matrix was substantially increased, with abundant amorphous ground substance. In contrast, veins obtained by the optimal method had intact endothelium both at implantation and thereafter. Adhesion of white cells and platelets to the endothelium did not occur. The media remained compact without inflammation and without modulation of the smooth muscle cells. We conclude that vein grafts prepared by the optimal technique do not develop early or late evidence of endothelial or medial injury. This should result in a nonthrombogenic graft immediately after surgery and diminished late intimal/medial hyperplasia.

Animals↗
PubMed1982

Management of vascular injuries to the leg.

Our experience with 69 vascular injuries in 56 patients led us to modify the management of vascular injuries to the leg. We believe that prompt and complete angiography whenever the general condition of the patient allows it, early fasciotomy when indicated before vascular repair, thrombectomy of the injured artery and vein and local instillation of heparinized saline solution, vascular repair before orthopedic stabilization of fractures in selected cases, external fixation of the fracture when there is significant soft tissue injury, and early skin grafting resulted in an improved level of care with a low morbidity and no mortality in our series.

Adolescent↗
PubMed1981

Intraoperative arteriography in femoropopliteal and femorotibial bypass grafts.

We reviewed our experience with intraoperative arteriography following femoropopliteal and femorotibial reconstruction during a five-year period beginning in January 1975. During 171 of 250 procedures an intraoperative arteriogram was performed. In nine (5.2%) instances, a correctable abnormality was detected. These consisted of three cases of distal anastomotic stenoses, two cases of intimal flaps, three cases of poor inflow, and one case of clot. Intraoperative arteriography may reveal a correctable abnormality in 5% of femoropopliteal and femorotibial bypass grafts and thus prevent early graft failure. The false-positive rate was 0.06%. In our experience, routine intraoperative arteriography has been a safe, easy to perform, and effective method of assessing technical problems in femoropopliteal and femorotibial reconstruction.

Femoral Artery↗
PubMed1981

Technical modifications in the placement of inferior vena caval filter devices.

Placement of 151 Mobin-Uddin vena caval umbrella filters and 17 Kimray-Greenfield vena caval filters since 1972 led us to make a number of technical modifications. The operative procedure is performed with local anesthesia in the vascular radiology suite. If the right internal jugular vein is narrowed and cannot be dilated, an approach through the left internal jugular vein is possible. The filters are advanced under fluoroscopic control after direct visualization of both renal veins. Since the patient is awake, he can be asked to roll on the left side if there is a tendency for the filter to advance into the hepatic veins or the right renal vein. Release of the filter is most accurately accomplished by withdrawing the carrier rather than advancing the filter. The carrier is then removed under fluoroscopic control and the internal jugular vein ligated. These modifications have resulted in a success rate of nearly 100 percent in recent filter placements, an operative morbidity of 8.3 percent and a 30 day hospital mortality of 8.9 percent.

Equipment and Supplies↗
PubMed1981

Protection of endothelium in vessel segments excised for grafting.

Contracture and collapse often complicate dissection and excision of blood vessels for grafting. Subsequent forceful redilatation and leak checking with cold saline almost always lead to partial or total denudation of endothelium, which increases the risk of early occlusion by thrombi or late occlusion by fibrocellular initimal thickening. To prevent endothelial damage, we used three major modifications of the excision and extracorporeal maintenance procedures: (1) adventitial application of the smooth-muscle relaxant papaverine in situ to avoid contracture and to allow subsequent gentle, gradual redilatation at low pressure; (2) balanced perfusion and maintenance fluid containing 10% protein (serum of albumin); and (3) extracorporeal maintenance of the vessel at body temperature. In an experimental extracorporeal vascular perfusion system, we could preserve morphologically intact endothelium of rabbit carotid arteries for over 3 hours, as evaluated by scanning electron microscopy. Applying the same principles to canine cephalic and saphenous veins, we gradually dilated the vessels at pressures as low as 100 mm Hg and obtained a morphologically intact endothelium after 1 hour of extracorporeal maintenance.

Animals↗