Biomedical subjects

J M Seeger

Publications and source records attributed to J M Seeger.

86 records · Page 5Linked to original sources

PubMed1987

Collagen content, histology, and tensile strength: determinants of wound repair in various gastric stapling devices in a canine gastric partition model.

Various stapling devices have been applied to create the small gastric pouch necessary for effective weight loss in morbid obesity, but it is unclear as to which staple line arrangement provides the most reliable gastric wound healing. Five variants of staple lines (Groups I-V) were used to create a gastric partition in 47 adult mongrel dogs (20-30 kg). Staple-line arrangements were as follows: Group I (n = 10)--two superimposed double rows (TA-90), Group II (n = 10)--prototype staple line of four rows 2.03 mm apart, Group III (n = 12)--two double rows of staples 6.5 mm apart, Group IV (n = 10)--prototype staple line of two double rows of staples 0.64 mm apart, and Group V (n = 5)--a single double-row staple line (TA-90). Staple lines were examined at 2, 4, 8, and 13-16 weeks for evidence of healing, histology, tensile strength, and collagen (hydroxyproline) content. Significant differences in staple-line disruption rates were found between all groups (chi 2, P less than 0.01). The prototype four-row staple line (Group II) had the most significant parameters of wound repair determined by biochemical evidence of wound healing and enhanced tensile strength. Staple-line arrangement appears to be an important determinant of gastric wound healing and may influence the rate of postoperative gastric partition disruption.

Animals↗

PubMed1987

Laser radiation in the treatment of prosthetic graft stenosis. A preliminary study of prosthesis damage by laser energy.

Transluminal laser recanalization is potentially an important new treatment of anastomotic intimal hyperplasia. However, currently used grafts or sutures may be damaged by laser radiation at power and energy levels required for plaque removal. To investigate this problem, two commonly used grafts (Dacron and polytetrafluoroethylene [PTFE]) and two types of vascular suture (polypropylene and PTFE) were exposed to argon laser radiation in vitro. Dacron and PTFE grafts recovered from amputations were also studied to determine whether graft "healing" affected graft resistance to laser damage. Power and energy levels required to perforate atherosclerotic superficial femoral arteries were determined for comparison. PTFE grafts were significantly (1.5 to 7 times) more resistant to perforation by laser energy than atherosclerotic arteries under all conditions. In contrast, Dacron grafts perforated at power and energy levels one half to one third of that required for vaporization of atherosclerotic plaque. PTFE sutures remained intact at power and energy levels above the levels that perforated atherosclerotic arteries, whereas polypropylene sutures were destroyed by very low levels of power and energy (0.5 joules at 0.5 watts). Because of the variable levels of power and energy that damage different types of prosthetic grafts and sutures, laser angioplasty should only be investigated clinically as a therapy for anastomotic intimal hyperplasia when PTFE grafts and sutures are present.

Blood Vessel Prosthesis↗

PubMed1987

Preoperative saphenous and cephalic vein mapping as an adjunct to reconstructive arterial surgery.

B-mode ultrasound was prospectively evaluated for its ability to preoperatively assess the adequacy of venous conduit for arterial reconstruction. Fifty-one patients who had lower extremity revascularization had real-time imaging of the saphenous and cephalic veins. Veins were judged adequate based on size, compressibility, and absence of sclerosis or intraluminal echoes. All mapped veins were explored and assessed by the standard criteria for suitability. Vein size was determined from completion angiograms, and wound complications recorded and compared with patients who had similar procedures in the 12 months before the use of vein mapping. Preoperative mapping was found to be accurate in 50 to 51 patients (98%). Vein size as determined by B-mode ultrasound correlated well with angiograms, R = 0.8539 overall with R greater than 0.9 in the last 7 months of the study. Wound complications occurred in 2% of the patients who had preoperative mapping and in 17% of the historic controls. Preoperative vein mapping using B-mode ultrasound is an accurate method of determining vein suitability for use in arterial reconstruction. It improves operative planning and can contribute to a reduction in wound complications. Veins determined to be unusable by preoperative scanning need not be explored.

Arm↗

PubMed1987

Intra-arterial streptokinase in the treatment of acute arterial thrombosis.

Streptokinase and catheter thrombectomy were retrospectively compared in 25 patients who presented with acute ischemia to investigate whether the use of intra-arterial streptokinase offers an advantage in the treatment of acute arterial or graft thrombosis. Streptokinase was used in all patients presenting with acute thrombosis unless the ischemic limb would not tolerate the time required for clot lysis. Complete thrombolysis was achieved in 47 per cent of the occlusions treated with streptokinase and initial limb salvage rate in 37 per cent of the patients. Subsequent surgical procedures were required in seven of eight patients with successful thrombolysis. Catheter thrombectomy reestablished vessel or graft patency in 86 per cent of the procedures and achieved initial limb salvage in 67 per cent of the patients. Long term (greater than six months) patency was achieved in 25 per cent of the patients treated with streptokinase and 44 per cent of the patients with catheter thrombectomy. Streptokinase did not prevent the need for further surgical intervention, improve early patency of these vessels or promote limb salvage when compared with that of catheter thrombectomy.

Acute Disease↗

PubMed1986

Laser angioplasty with angioscopic guidance in humans.

An experimental study was conducted in 11 patients to evaluate the immediate effects of laser recanalization during peripheral arterial bypass surgery. Angioscopy allowed precise localization and identification of the occlusion. A 1 or 2 mm optical fiber probe was used. Laser energy was regulated using the least amount of energy necessary for recanalization. New vascular channels were made in 10 of the 11 patients. After recanalization the arterial segment was excised for histologic evaluation. Smaller channel diameters were made with the 1 mm probe (1.5 +/- 0.6 mm) than with the 2 mm probe (3 +/- 0.3 mm) (p less than 0.05). Flow through channels (mean pressure 80 mm Hg) made with the 2 mm probe was greater than that through channels made with the 1 mm probe (150 +/- 102 versus 19.7 +/- 10 cc/min) (p less than 0.05). The amount of debris formed was small with both probes. Vascular perforations were less frequent with the 2 mm probe (two of nine arteries) compared with the 1 mm probe (four of four arteries). Successful recanalization with flow rates expected to maintain vascular patency was achieved only with the 2 mm probe. Histologic studies at nonperforated sites demonstrated that the elastica of the artery appeared to be preserved whereas the overlying plaque and underlying media were thermally disrupted. This suggests that the elastic tissue acts as an optical window allowing the argon beam to go through it without causing morphologic damage. Except for fresh thrombus, atheromas including calcific plaque and old organized thrombus were readily vaporized. These results are encouraging for the use of the laser for vascular recanalization in humans.

Aged↗

PubMed1986

Angioscopy as an adjunct to arterial reconstructive surgery: a preliminary report.

To date our use of angioscopy as an adjunct to in situ vein grafting, arterial embolectomy, femoropopliteal bypass surgery, and laser recanalization has been studied in 11 patients. Three angioscopes have been used: a 1.7 mm optiscope, a 2.8 mm laser optiscope, and a 3.2 mm bronchoscope. Scopes were introduced through an arteriotomy and a clear field maintained by continuous saline infusion. Twenty-four angioscopic evaluations were performed in the 14 patients studied. Adequate visualization was achieved with all three scopes. Angioscopy showed total atherosclerotic occlusion of six superficial femoral and popliteal arteries, intimal flaps in two arteries, thrombus in two arteries and one graft, adequate valvulotomy in three saphenous veins used for in situ bypass grafting, and removal of thrombus after embolectomy in one artery. With the 2.8 mm laser optiscope, the optical fiber used for laser recanalization could be positioned at the site of arterial occlusion before lasing and recanalization were done under direct vision. The 1.7 mm scope could be passed through the recanalized artery to inspect the channel and confirm communication with the artery distal to the occlusion. Thus, angioscopy appears to be potentially useful as a diagnostic device in arterial occlusive disease and as an adjunct in in situ saphenous vein grafting or laser recanalization of occluded arterial segments.

Arterial Occlusive Diseases↗

PubMed1986

Preoperative CT in symptomatic abdominal aortic aneurysms: accuracy and efficacy.

Of 80 patients who underwent operations for abdominal aortic aneurysm at the Gainesville Veterans Administration Medical Center, 23 had a preoperative CT scan. Twenty patients in this group were symptomatic. In determining the presence of rupture, there was only one false-negative examination and no false-positives for a sensitivity of 0.9 and a specificity of 1.0. Nine of the 20 symptomatic patients had a rupture confirmed at laparotomy, and these patients had a 22 per cent mortality. Unruptured symptomatic patients operated upon after an expeditious preparation (usually about 36 hr), including optimization of cardiac output and mechanical bowel cleansing, had a mortality of 30 per cent primarily for postoperative myocardial infarction and left ventricular failure. The high operative mortality previously reported for emergently repaired unruptured symptomatic abdominal aortic aneurysms (18%) was not diminished by limited preoperative preparation.

Aged↗

PubMed1985

The healing process in normal canine arteries and in atherosclerotic monkey arteries after transluminal laser irradiation.

To evaluate the healing response of both normal and atherosclerotic arteries to laser radiation, 7 mongrel dogs and 4 hypercholesterolemic atherosclerotic monkeys underwent catheterization with a right Judkins catheter-optical fiber system designed to maximize arterial wall injury. Argon laser radiation was then delivered to the abdominal aorta and iliofemoral arteries. In the 11 animals, a total of 917 sites were irradiated in 33 arteries. Angiography did not reveal dissection or aneurysm formation; occlusive thrombosis was found in 2 arteries. Perforation of the arterial wall was a frequent complication. In animals killed between 1 hour and 4 days, light and electron microscopy of lased sites showed craters filled with a coagulum of blood and cellular debris with only a few adherent platelets. Healing occurred with a minimal inflammatory response and involved both fibroblasts and smooth muscle cells. Reendothelialization was seen in all animals killed between 7 and 14 days after lasing and was complete by 30 to 60 days. Within this period, no accelerated atherosclerosis was seen at lased sites in the hypercholesterolemic monkeys. It is concluded that transluminal lasing of normal arteries in dogs and in atherosclerotic arteries of monkeys is followed by healing and reendothelialization within a few weeks.

Angiography↗

PubMed1985

Improved endothelial cell seeding with cultured cells and fibronectin-coated grafts.

A possible approach to the low seeding efficiency of endothelial cells into prosthetic grafts is to increase the number of cells to be seeded in cell culture and improve seeding efficiency by graft precoating with fibronectin. The effect of cell culture on cell adhesion is unknown, however, and fibronectin also binds fibrin, which may increase the thrombogenicity of the graft luminal surface. To investigate these questions, freshly harvested canine jugular vein endothelial cells from six animals and similar cells harvested from six primary and eight secondary cell cultures were labeled with 111Indium and seeded into 5 cm, 4 mm PTFE grafts coated with fibronectin, using similar uncoated PTFE grafts as controls. Platelet accumulation and distribution on six similar coated and uncoated grafts placed in canine carotid, external jugular arterial venous shunts for 2 hr were also determined using autogenous 111Indium-labeled platelets. Significant differences between group means were determined using the paired Student's t test. Results reveal that seeding efficiency is significantly better in all groups of coated grafts compared to uncoated grafts (P less than 0.01). Cells derived from cell culture also had significantly higher seeding efficiencies than freshly harvested cells when seeded into coated grafts (P less than 0.05) and tended to have higher seeding efficiencies than harvested cells when seeded into uncoated grafts (P = 0.53). Fibronectin coating increased mean platelet accumulation on the entire graft luminal surface, but not to a statistically significant degree (P greater than 0.1). Whether this increased seeding efficiency will improve graft endothelialization remains to be investigated.

Animals↗

PubMed1985

The arm as an alternative site for vascular access for dialysis in patients with recurrent access failure.

Patients with chronic renal failure requiring dialysis and in whom multiple attempts at vascular access have previously failed represent a challenge to vascular surgeons. In these difficult patients the arm offers an excellent site for either an autogenous fistula or a prosthetic shunt because of the relatively unharmed portion of the upper cephalic vein or the protected location of the brachial vein in most individuals. (The anatomic region of the arm by definition is the area between the shoulder and the elbow.) Over the last two years we have studied 15 patients with a mean of 2.5 previously failed shunts or fistulas who subsequently had vascular access procedures in the arm, with the brachial artery as the inflow and the cephalic vein or brachial vein as the outflow. The first choice was the cephalic vein transposition to the brachial artery because it involved only one anastomosis and is autogenous vein. The alternative was a prosthetic graft of polytetrafluoroethylene (PTEE) between the brachial artery and the cephalic vein or brachial vein in the arm. The patency rate of these arm access procedures has been 75%. None of these patients had had congestive heart failure, distal ischemia, or excessive hematoma formation. The arm represents an excellent source for fistula or shunt construction in those difficult patients in whom previous vascular access sites have already failed.

Arm↗

PubMed1983

Autogenous graft replacement of infected prosthetic grafts in the femoral position.

Infected prosthetic grafts in the femoral position remain among the most challenging problems in vascular surgery. Over the past 2 years, 11 patients with this critical condition have undergone graft reconstruction with autogenous tissue as described by Ehrenfeld. All infected prosthetic material was removed and replaced by an autogenous graft. The autogenous grafts were constructed with endarterectomized superficial femoral, iliac, and aortic segments as well as portions of saphenous and cephalic veins. This procedure has proven successful, resulting in only one amputation (undertaken with a still functioning autogenous graft) in the series. There was one postoperative death. Six grafts failed in long-term follow-up, due in all cases to inadequate flow because of stenosis of the saphenous vein portion of the autogenous reconstruction. However, the patients were usually free of infection by this time and underwent successful prosthetic reconstruction.

Aorta, Abdominal↗

PubMed1977

Preoperative selection of patients for lumbar sympathectomy by use of the Doppler index.

Yao and Bergan [8] have shown that an ankle systolic index of more than 0.25 is associated with a high rate of success from lumbar sympathectomy. This association has been borne out in our small series. We have also suggested that diseases that obviously compromise collateral circulation might be a relative contraindication to sympathectomy. Although incomplete, literature on collateral flow in relation to sympathectomy tends to confirm this idea. Consideration of such diseases as a contraindication to sympathectomy might further increase the success rate after sympathectomy. Regardless, ankle systolic index alone appears to be a reliable objective, non-invasive method of selecting patients with an increased chance of success from lumbar sympathectomy.

Adult↗

PubMedDate not supplied

Secondary femoral-distal bypass.

Thirty-nine secondary femoral-distal (femorotibial and femoroperoneal) bypasses were reviewed and compared to 89 primary femoral-distal bypasses (done during the same time period) to investigate the efficacy of secondary femoral-distal bypass. Graft patency at 2 years by life table analysis was similar in both groups (38% primary group vs 36% secondary group). However, limb salvage was significantly less in the secondary group (52% vs 68% at 2 years, p less than 0.05). This decrease was primarily due to poorer limb salvage using composite grafts (prosthetic/vein) compared to vein grafts in patients who underwent secondary femoral-distal bypasses (37% vs 76% at 2 years, p less than 0.05). Postoperative wound infections and mortality were similar in both groups. Thus, femoral-distal bypass after failure of a previous infrainguinal reconstruction offers good long-term limb salvage with acceptable surgical risk when autologous vein is available for use as the arterial conduit.

Arteriovenous Shunt, Surgical↗

PubMedDate not supplied

Embolic and occlusive complications from thrombosed femorofemoral grafts.

Five episodes of acute arterial occlusions associated with thrombosed femorofemoral grafts are reported. Four of these occlusions were directly associated with trauma to the graft and were thought to be embolic. All patients had thrombus extending from the thrombosed graft into the femoral artery, threatening the survival of the lower extremity. We recommend that when a graft thrombectomy is not performed, or is not successful, the thrombosed femorofemoral graft should be detached or excised as prophylaxis against embolic and occlusive complications.

Adult↗