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Biomedical subjects

D P Flanigan

Publications and source records attributed to D P Flanigan.

At least 19 recordsLinked to original sources
PubMed1991

A nine-year experience with crossover femoro-femoro-popliteal sequential bypass.

Multisegmental arterial occlusive disease may require a combined inflow and outflow procedure for optimal treatment of limb ischemia. Twenty-one patients with unilateral iliac artery stenosis or occlusion and ipsilateral superficial femoral artery occlusion underwent crossover femoro-femoro-popliteal sequential bypass during a 9-year period. Seventeen operations were for limb salvage. Patency rates were determined separately for each segment of the bypass. Primary patency rates for the femoro-femoral segment were 89%, 83%, and 57% at 1, 2, and 5 years, respectively. Primary patency rates for the femoro-popliteal segments were 68%, 62%, and 40% at 1, 2, and 5 years, respectively. Limb salvage rates were 100%, 90%, and 77% at 1, 2, and 5 years, respectively. This experience indicates that femoro-femoro-popliteal bypass is an effective treatment in selected patients with severe ischemia due to combined iliac artery and superficial femoral artery disease.

Aged↗
PubMed1991

Differential detection of plasma hydroperoxides in sepsis.

OBJECTIVE: To determine whether plasma lipid hydroperoxides may be a useful marker for sepsis. DESIGN: Exploratory, open-label study. SETTING: Critical care unit at a university medical center. PATIENTS: Twelve patients with sepsis syndrome requiring hemodynamic monitoring with pulmonary artery catheters. Seven patients were diagnosed with pulmonary infections and five patients had intra-abdominal infections. INTERVENTIONS: Fatty acid hydroperoxide was measured in the fresh arterial plasma (radial artery) and mixed venous plasma (pulmonary artery) from each patient. Hydroperoxide was determined using a sensitive assay based on activating the cyclooxygenase reaction of prostaglandin H synthase. MEASUREMENTS AND MAIN RESULTS: The mean difference between the amount of fatty acid hydroperoxide measured in the plasma draining involved regions (arterial plasma for pulmonary sepsis, mixed venous plasma for intra-abdominal sepsis) compared with the paired, uninvolved regions was 0.45 +/- 0.14 microM (mean +/- SEM; p less than .005). CONCLUSIONS: Increased lipid hydroperoxides in blood-draining septic foci are markers of oxyradical release associated with severe infection, although they are not specific for infectious conditions, being released also from nonseptic regions of surgical trauma. Assays for hydroperoxides may be useful when relatively free of other tissue trauma.

Adult↗
PubMed1990

The natural history of intimal flaps in a canine model.

The natural history of arterial intimal flaps has not been well defined. This study characterizes the natural history of unrepaired intimal flaps. Thirty-nine 1-, 2-, and 3-mm hemispheric, distally based intimal flaps were made in 4- to 5-mm diameter canine femoral and carotid arteries. Twenty arteries had 2- and 3-mm intimal flaps and were monitored for short-term arterial thrombosis and flap extension. Nineteen had 1- and 2-mm intimal flaps and were monitored for thrombosis, long-term development of neointimal hyperplasia, arterial stenosis, and persistence of the flap. While 40% of the arteries with 3-mm intimal flaps developed thrombosis in 3 to 5 days, only 3% of the arteries with 1- or 2-mm intimal flaps developed thrombosis. Most 1- to 2-mm intimal flaps resolved and the subsequent development of neointimal hyperplasia or arterial stenosis was minimal. Arteries with hemodynamically significant stenoses from intimal flaps warrant repair, while arteries with smaller intimal flaps may not require repair.

Animals↗
PubMed1990

Differences between arterial and mixed venous levels of plasma hydroperoxides following major thoracic and abdominal operations.

Fatty acid hydroperoxides in the plasma of 18 patients who were undergoing normal postoperative periods following major thoracic or abdominal operations were measured by using a sensitive assay based upon the activation of the cyclooxygenase activity of prostaglandin H synthase. Following major thoracic operations of nine patients, the mean difference between the arterial (0.49 +/- 0.13 microM, mean +/- S.E.M.) and mixed venous (-0.09 +/- 0.12 microM) level of hydroperoxide was 0.58 +/- 0.13 microM (p less than 0.01). In marked contrast to this result, major abdominal operations of nine patients led to a mean difference between the arterial (-0.19 +/- 0.16 microM) and mixed venous (0.46 +/- 0.08 microM) hydroperoxide levels of -0.65 +/- 0.17 microM (p less than 0.01). Both pulmonary and intraabdominal tissues appear capable of generating significant amounts of fatty acid hydroperoxide in response to standard surgical procedures. The A-MV differences suggest that the blood-borne hydroperoxides were rapidly cleared from the circulation by tissue capillary beds.

Abdomen↗
PubMed1990

A rapid, accurate, noninvasive technique for diagnosing critical and subcritical stenoses in aortoiliac arteries.

Accurate hemodynamic evaluation of the aortoiliac system for the purpose of determining the need for an inflow procedure currently requires invasive pressure measurements. This study was undertaken to evaluate a noninvasive technique with the aortofemoral transfer function. Twenty-eight human aortoiliac segments were studied with intraarterial pressure measurements, with and without papaverine injection, and by calculation of the Doppler-derived mean power frequency index obtained by digital signal processing of aortic and femoral spectra. The procedure is menu driven and can be performed by any duplex ultrasound technologist. This technique involves recording 20 aortic and 20 femoral Doppler signals, requiring less than 1 minute of data acquisition time. Intraarterial pressure measurements were used to classify arteries into the three following groups: (1) normal arteries, (2) arteries with subcritical stenoses, and (3) arteries with critical stenoses. The mean power frequency index of group 1 arteries (n = 7) was 0.63 +/- 0.04, of group 2 arteries (n = 6) was 0.46 +/- 0.02, and of group 3 arteries (n = 15) was 0.21 +/- 0.05. These mean power frequency index values were significantly different by analysis of variance (ANOVA) (p less than 0.0001). Each group could be differentiated from the other groups with a sensitivity of 0.83 to 1.00, a specificity of 1.00, and an accuracy of 0.92 to 1.00 compared to intraarterial pressure measurements, including papaverine testing. Measurement of the mean power frequency index is a rapid, noninvasive technique that diagnoses and quantifies aortoiliac stenoses with an accuracy similar to intraarterial pressure measurements.

Aortic Diseases↗
PubMed1990

Hollenhorst plaques: retinal manifestations and the role of carotid endarterectomy.

The ocular examinations and hospital records of 64 patients with Hollenhorst plaques were retrospectively reviewed to document any associated visual defects and to determine if carotid endarterectomy prevented the occurrence of new plaques or symptoms. One hundred nine Hollenhorst plaques were seen in 75 eyes; 18 had multiple plaques simultaneously. Visual field defects were noted in 14 eyes, four of which corresponded to the location of Hollenhorst plaques. Twenty-eight carotid endarterectomies were performed ipsilateral to a Hollenhorst plaque: 24 patients had no symptoms; four patients developed new ipsilateral asymptomatic Hollenhorst plaques at 1 to 50 months after operation. Two late strokes occurred, one of which was ipsilateral to a new Hollenhorst plaque, during a mean follow-up of 50 months (range 8 to 102 months). Thirty-seven eyes with asymptomatic Hollenhorst plaques did not undergo ipsilateral operation. Two eyes developed new Hollenhorst plaques during a mean follow-up of 23 months (range 1 to 132 months). Eight eyes in patients with no symptoms had multiple Hollenhorst plaques, one of which was associated with a subsequent stroke. Of the 29 eyes with a single Hollenhorst plaque, one subsequently experienced an ipsilateral stroke, and another had a transient ischemic attack (1 and 3 years later, respectively). Visual field defects infrequently corresponded to locations of Hollenhorst plaques. The cerebral hemisphere ipsilateral to asymptomatic plaques had a slightly increased risk of subsequent transient ischemic attack or stroke compared to the contralateral side without Hollenhorst plaques. The number of simultaneous Hollenhorst plaques in the retinal circulation did not predict clinical outcome.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1989

The role of isolated profundaplasty for the treatment of rest pain.

This study was undertaken to determine the efficacy and durability of profundaplasty and define preoperative factors predictive of success. The hospital charts, vascular laboratory data, and arteriograms of 20 patients having 21 isolated profundaplasties for ischemic rest pain between 1979 and 1987 were reviewed. Follow-up extended to 72 months (mean, 26 months). Early success was achieved in 12 extremities (57%) and life-table analysis showed continued success to six years in 11 extremities (55%). Of the multiple preoperative factors assessed, only a low-thigh/ankle gradient pressure index (TAGI) of less than 0.55 was predictive of success. Life-table analysis for limbs with a TAGI of less than 0.55 showed an 89% success rate at six years compared with only a 32% success rate for limbs with a TAGI of more than 0.55. Isolated profundaplasty for the treatment of ischemic rest pain can be an efficacious and durable procedure when patients are selected based on objective hemodynamic measurements.

Arteries↗
PubMed1989

Open transmetatarsal amputation in the treatment of severe foot infections.

Severe forefoot infections may lead to limb loss, even if addressed aggressively. Infection or gangrene that compromises the plantar skin flap may preclude a standard transmetatarsal or midfoot amputation, thereby culminating in a below-knee amputation. We report a series of forefoot infections with loss of the distal plantar skin. Open or guillotine amputation at the mid-metatarsal level led to a high rate of healing and a durable stump, provided that the level of infection did not extend beyond the metatarsal heads. Wound closure was obtained by wound contracture alone or by use of partial-thickness skin grafting. Rehabilitation was dependable. The association of diabetes mellitus or gangrene did not adversely affect outcome. Open transmetatarsal amputation is a safe surgical option preferable to midfoot or below-knee amputation for the treatment of severe forefoot infection that does not extend proximally beyond the metatarsal heads.

Amputation, Surgical↗
PubMed1989

Reduced intimal injury to canine arteries with controlled application of vessel loops.

Arterial intimal damage caused by elastic vessel loops was quantitated to determine (1) if they produce intimal injury, (2) if the injury is proportional to the force applied, and (3) if the injury is less than that produced by vascular clamps. Vessel loops were wrapped around 30 canine artery segments (5 mm in diameter) and a gram scale was connected to each to measure the force applied. The minimal occlusive force (MOF) and 150, 200, and 250 g force were applied for 30 min. For comparison, a Fogarty vascular clamp was applied at MOF for 30 min. Arteries were then reperfused for 30 min. Half was immediately harvested (group I); the remaining half was harvested at 2 weeks (group II). Scanning electron micrographs were made of each artery's intimal surface and graded from 0 (no injury) to 5 (severe intimal fracture). Mean injury grades were calculated. The MOF for vessel loops was 99 g. In group I, arteries subjected to less than 200 g force had a mean injury grade of 1.0 +/- 0.4; while those exposed to 200-250 g force had an injury grade of 3.5 +/- 0.7. The severity of injury was linearly correlated with the force applied (r = 0.72, P less than 0.009). In group II, the injury grade of 0.4 +/- 0.5 in arteries at MOF was significantly less than the injury grade of 2.8 +/- 0.5 in those at 200-250 g force, (P less than 0.0005). Injury grades of 3.7 and 3 were seen in groups I and II, respectively, when Fogarty clamps were applied. We conclude that vessel loops applied at MOF produce minimal injury. At greater occlusive forces, the injury is proportional to the force applied approaching that of a Fogarty clamp. Intimal injuries may be minimized when vessel loops are applied at MOF.

Animals↗
PubMed1989

Repair of abdominal aortic aneurysms in patients with renal, iliac, or distal arterial occlusive disease.

Appropriate preoperative vascular assessment of patients presenting with aortic aneurysms and arterial occlusive disease is essential to obtain the optimal results from aneurysm repair. The renal arteries should be evaluated in patients with hypertension or renal dysfunction, and stenosis must be addressed when seen on arteriograms. Hemodynamically significant lesions are candidates for bypass concomitant with aortic replacement. The stump pressure of a patent inferior mesenteric artery should be assessed intraoperatively, and bypass or reimplantation should be performed if colon ischemia might result from internal mesenteric artery ligation. If vasculogenic impotence is suggested by preoperative studies, meticulous nerve-sparing dissection and revascularization of the internal iliac arteries may result in recovery of erectile function in some patients. In all cases of aneurysm repair, the hypogastric circulation must be maintained through either direct revascularization or bypass to major collateral arteries. Iliac occlusive disease may be evaluated with several modalities, including physical examination, noninvasive laboratory testing, arteriography, and the papaverine test, to determine whether critical or subcritical stenoses are present. Aortic bifurcation grafts should be used to construct the distal anastomoses beyond areas of significant disease. The extent of lower-extremity occlusive disease directly affects the long-term patency of aortic replacement, and diligent follow-up is necessary for timely intervention to maintain patency of vascular reconstructions.

Aorta, Abdominal↗
PubMed1989

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.

Adult↗
PubMed1989

The fate of unrepaired minor technical defects detected by intraoperative ultrasonography during carotid endarterectomy.

This report describes the natural history of unrepaired minor technical defects detected by intraoperative B-mode ultrasonography during carotid endarterectomy. Intraoperative ultrasonography was used to assess the technical adequacy of 80 carotid endarterectomies. Sixty-two arteries were normal on intraoperative ultrasound examination, whereas the remaining 18 arteries had a total of 21 minor residual technical defects. The 21 minor defects consisted of four internal carotid artery lesions, nine common carotid artery lesions, and eight external carotid artery lesions, 19 had 1 to 3 mm intimal flaps, and two had small stenoses. Sixteen of the 19 intimal flaps resolved before the first postoperative ultrasound study. These arteries had normal examination results, which indicated that these intimal flaps had healed. The two stenoses detected intraoperatively could not be detected by postoperative carotid duplex scanning at 1 month follow-up. No statistically significant relationship was found between the presence of a minor residual defect on intraoperative ultrasonography and the subsequent development of recurrent stenosis or occlusion in any of the arteries assessed. These data suggest that certain minor technical defects in the carotid artery that were detected by intraoperative ultrasonography are benign and may not require repeat exploration of the carotid artery for repair.

Actuarial Analysis↗
PubMed1989

Lupus-like anticoagulants and lower extremity arterial occlusive disease.

Lupus-like anticoagulants (LLA), lupus anticoagulant and/or anticardiolipin antibody, are increasingly recognized in association with venous and arterial thrombotic events. We recently reviewed our experience with patients undergoing revascularization for lower-limb ischemia who were found to have LLA. Nine patients had LLA based on a prolongation of the partial thromboplastin time or by anticardiolipin assay by an enzyme-linked immunosorbent assay system. The ages of the patients ranged from 23 to 57 years. There were seven (78%) men, six (67%) blacks, two (22%) diabetic patients, and three (33%) hypertensive patients. One patient had systemic lupus erythematosus. All patients except one were cigarette smokers. Four patients had concurrent regulatory protein abnormalities: three protein C deficiencies, one protein S deficiency, and one plasminogen deficiency. The nine patients had 10 lower-extremity arterial reconstructions with two postoperative failures within 30 days. Patients were anticoagulated with heparin or aspirin after all but one operation. Patients at risk were identified on the basis of age (less than 51 years), unexplained early graft thrombosis, or history of venous or arterial thrombotic events. This group of patients is believed to be at risk for early postoperative thrombosis. Postoperative anticoagulation after revascularization for patients with LLA may be beneficial.

Adult↗
PubMed1989

Computerization of academic vascular surgery.

Academic surgical units have a combination of computer needs, including access to the surgical literature, storage and retrieval of patient registry data, laboratory, and research data, generation of reports; statistical analysis of data; and word processing. A system that fulfills these requirements was developed for an academic vascular surgical unit. The system integrates these functions in a multi-user environment and is accessed from menus on multiple terminals in laboratories and offices in three hospitals and in staff members' homes. Databases currently include more than 7000 references to published articles in vascular surgery, a vascular registry consisting of more than 7500 patients, patient data from three integrated noninvasive vascular laboratories, data generated from both clinical and basic research, and a log of resident, fellow, and faculty operative experience. Statistical analysis, using essentially all modern statistical methods including sophisticated log-rank, proportional hazards, and multivariant analyses, can be performed on all databases, either separately or in any combination, without the need to reenter data. An electronic mail and messaging system provides for paperless communication between surgeons, research personnel, and clerical staff.

Academic Medical Centers↗
PubMed1988

Risk factors affecting the natural history of intermittent claudication.

To determine the prognostic significance of the level of arterial disease in claudicators, risk factors affecting the progression of intermittent claudication, including hemodynamic variables obtained from noninvasive vascular laboratory examinations, were assessed. We identified 378 patients with intermittent claudication by characteristic history and the presence of abnormal treadmill exercise examination results. Results of serial examinations were available for 195 of these patients, who had 310 claudicating limbs. Life-table analysis revealed that after eight years, 41% of these patients had progressed to critical ischemia, defined as rest pain or tissue loss, and 50% had died. Cox proportional hazards general linear regression analysis found that at a patient's first examination in the vascular laboratory, the ankle-brachial index and the decrease in ankle-brachial index after exercise were significantly associated with the subsequent development of critical ischemia. The level of disease at the initial examination in the vascular laboratory was not a significant risk factor for progression to critical ischemia and therefore should not be used as an indicator for or against operation in patients with intermittent claudication.

Adult↗
PubMed1988

Analysis of 18 recent cases of penetrating injuries to the common and internal carotid arteries.

Penetrating injuries to the common and internal carotid artery carry the unique potential for irreversible neurologic damage, respiratory collapse, and exsanguination. This study analyzes a recent 4 year experience with 18 cases of penetrating injury to the carotid artery to identify the factors influencing surgical decision-making, perioperative complications, and mortality. Sixteen patients with acute respiratory distress required emergent airway intubation. Three patients in hemorrhagic shock were brought directly to the operating room; the remaining 15 underwent emergency carotid arteriography. Three patients with multiple intramediastinal vascular injuries exsanguinated on the operating table before hemorrhage could be controlled. There were no deaths or neurologic complications in the 14 surviving patients who had an operation on the carotid artery, including 2 patients treated by internal carotid artery ligation. Early control of the airway was the most common initial requirement in this group of patients. Judicious use of preoperative arteriography was thought to facilitate the operative approach in selected patients. A flexible surgical approach to the damaged carotid artery is essential based on the patient's hemodynamic status, degree of neurologic impairment, and nature and extent of arterial damage.

Adolescent↗