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Biomedical subjects

W R Flinn

Publications and source records attributed to W R Flinn.

At least 55 records · Page 3Linked to original sources
PubMed1989

Collagen types and matrix protein content in human abdominal aortic aneurysms.

Deficiencies of total collagen, type III collagen, and elastin have been proposed to explain aneurysm formation. Infrarenal aortas were collected from 19 patients (age 70 +/- 7 years) undergoing operative repair of abdominal aortic aneurysms (diameter 7 +/- 2 cm) and from 13 autopsies (age 63 +/- 17 years) of patients without aneurysm disease (controls). Wall thickness and collagen and elastin concentration were determined in full-thickness aorta. Collagen types I and III were measured after digestion with cyanogen bromide, which solubilized nearly 90% of total collagen for typing. Cyanogen bromide peptides were separated by sequential carboxymethylcellulose and agarose chromatography and quantified by peak area measurement with computerized image analysis. Histologic examination revealed prominent inflammatory cell infiltration and deficient, fragmented elastin in the aneurysms. Aortic wall thickness was similar in aneurysms and in control specimens. In the aneurysms, collagen was increased (37% +/- 16% vs 24% +/- 5%; p less than 0.05) and elastin was decreased (1% +/- 1% vs 12% +/- 7%; p less than 0.001), expressed as a percentage of delipidized, decalcified dry weight. Collagen type I accounted for 74% +/- 4% of aneurysm and 73% +/- 4% of control collagen solubilized for typing, and collagen type III accounted for 26% +/- 4% of aneurysm and 27% +/- 4% of control collagen solubilized for typing. Neither patients with a family history of aneurysms nor those without a history of aneurysms had collagen type III deficiency. Atherosclerotic abdominal aortic aneurysms are associated with an inflammatory process and may result from elastin degradation and not a deficiency of type III collagen.

Aged↗
PubMed1989

Duplex ultrasound measurement of changes in mesenteric flow velocity with pharmacologic and physiologic alteration of intestinal blood flow in man.

Duplex ultrasound scanning has been used to assess mesenteric blood flow in normal and disease states. To investigate this technique we studied nine normal volunteers at rest and under conditions known to modify intestinal blood flow. After a baseline mesenteric duplex scan, each subject was given one of three treatments in random order: (1) test meal (710 kcal), (2) intravenous glucagon (40 micrograms/min), or (3) intravenous vasopressin (0.2 units/min). Peak systolic and diastolic velocities and vessel diameters were measured at intervals after treatment in the celiac and the superior mesenteric arteries (SMAs) and the right common carotid artery. Resting velocities did not differ among the groups. Peak systolic velocity increased significantly in both celiac and SMAs after the meal, with maximal changes in the celiac artery preceding those in the SMA in most subjects. Early diastolic flow reversal in the SMA was consistently lost after the meal (eight of nine subjects). Velocity changes after glucagon closely paralleled those after the meal. Vasopressin produced significant decreases in peak systolic velocity in both visceral vessels. No changes in vessel diameter were noted after any treatment. Coefficient of variation for repeated measures of peak velocities was 19% in the celiac and 12% to 16% in the SMA and the common carotid. The coefficient of variation for repeated measurements of arterial diameter was 6% to 8% in the SMA and 11% in the celiac artery. Clinically relevant changes in mesenteric hemodynamics can be reproducibly detected and quantitated by means of current duplex ultrasound technology. The similarities between the visceral arterial responses to a meal and glucagon are of interest.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Upper extremity arterial injury in athletes.

Between 1983 and 1986, 23 athletes were evaluated for arm and hand complaints. Eleven players had symptoms of thoracic outlet compression. Severe arm fatigue (eight patients) and finger ischemia (three patients) were the presenting symptoms. In the remaining 12 athletes, symptoms of hand ischemia were predominant. Noninvasive testing with Doppler ultrasonography and duplex scanning (positional testing and finger systolic pressure recording) and cold immersion were used to aid in diagnosis. In the 11 athletes with thoracic outlet compression, arteriography confirmed the finding with compression of the subclavian artery in five, the axillary artery in one, both subclavian and axillary arteries in two, posterior humeral circumflex artery in one, and subclavian aneurysm in two. Compression of the suprascapular artery was identified in four, the subscapular artery in two, and the posterior humeral circumflex artery in one. Thrombosis of a first baseman's ulnar artery and occlusion of the palmar arch in a frisbee player were documented by arteriography. Decompression of the thoracic outlet consisted of anterior scalenectomy in five, pectoralis minor muscle division in one, and resection of both muscles in two. Removal of cervical rib with interposed vein graft was performed in the two players with arterial aneurysm. Hand ischemia in the remaining athletes was treated conservatively with Dextran-heparin infusion for acute ischemia. Repeat noninvasive study of all players demonstrated absence of compression in their playing position, and all have resumed their playing careers. Hand ischemia in athletes can be evaluated noninvasively and treated conservatively. Resection of hypertrophied muscles to decompress the thoracic outlet together with release of branch artery compression in selected athletes promotes perfusion to arm and shoulder muscles and helps to avoid the catastrophic complication of repetitive trauma leading to sudden arterial thrombosis.

Adolescent↗
PubMed1988

Multiple aneurysms in Behçet's disease.

Behçet's disease is characterized by recurrent ulcers of the mouth and genitalia and relapsing iritis. It is now recognized as a chronic multisystem disease affecting the skin, mucous membranes, eye, joints, central nervous system, and blood vessels. One of the known vascular complications of Behçet's disease is aneurysm formation or venous thrombosis. The two patients with Behçet's disease in this report developed multiple aneurysms over a short time span. Vascular surgeons dealing with young adults with peripheral aneurysms must be aware of this uncommon yet challenging clinical entity.

Adult↗
PubMed1988

The demise of primary profundaplasty.

Although the importance of the profunda femoris artery in maintenance of lower extremity integrity was recognized in the earliest days of modern vascular surgery, disappointment with the performance of primary profundaplasty has emerged fully only in recent years. During the 10 year period from 1977 to 1987, only 17 patients were subjected to this procedure at Northwestern Memorial Hospital. The nine men and eight women averaged 65.6 years in age and exhibited the usual precursors of arterial insufficiency: a history of smoking in 12 patients (71 percent), clinical coronary artery disease in 8 patients (47 percent), hypertension in 7 patients, diabetes mellitus in 6 patients, hyperlipidemia in 2 patients, and uremia in 1 patient. Four patients exhibited hemodynamic improvement after profundaplasty (ankle-brachial index increase of greater than 0.15). Four required amputation postoperatively, and a fifth exhibited hemodynamic failure 9 months postoperatively and required amputation. Two patients required subsequent femoral-to-peroneal bypass to improve distal arterial perfusion. One patient died after the procedure, for a 5.9 percent mortality rate. Thus, the fact that profundaplasty has proved disappointing in the treatment of severe arterial insufficiency deserves emphasis at this time.

Adult↗
PubMed1988

Improved long-term patency of infragenicular polytetrafluoroethylene grafts.

This article reviews late graft patency and the incidence of postoperative complications in 75 infragenicular polytetrafluoroethylene bypass grafts (20 posterior tibial, 26 anterior tibial, and 29 peroneal). All patients received a heparin infusion after operation and were switched to warfarin before discharge to maintain coagulation parameters (prothrombin time and partial thromboplastin time) approximately twice that of control subjects. Primary procedures were done in 14 patients (19%), and the remaining patients had one or more previous procedures. Ninety-seven percent of patients had limb-threatening ischemia. Graft patency was confirmed by interval examinations and Doppler ankle pressure measurements. The mean follow-up was 36 months, and long-term graft patency (4 years) was determined by life-table analysis. The 2-year cumulative patency rate for this group was 45% and the 4-year patency rate was 37%. The latter is significantly better than the patency rates of 12% reported for similar untreated randomized grafts. Anticoagulation was subtherapeutic in 15 patients at the time of graft thrombosis, and if these were excluded, the 2- and 4-year patency rates were 58% and 50%, respectively. Hematomas requiring drainage occurred in 10 patients (13.3%) and six patients (8%) developed wound infections, but graft infection occurred in only two patients. Two patients (2.6%) developed late bleeding complications necessitating cessation of the warfarin. There was one fatal perioperative myocardial infarction (1.3%) and four late deaths, none of which were related to the warfarin therapy. Although the incidence of postoperative hematoma and wound infection was increased, late complications occurred infrequently.(ABSTRACT TRUNCATED AT 250 WORDS)

Amputation, Surgical↗
PubMed1988

The effect of distal arterial anatomy on the success of popliteal aneurysm repair.

The success of bypass grafting for popliteal aneurysms may be compromised by the natural history of these lesions. During a 9-year period 35 patients had repair of 48 popliteal aneurysms. Elective repair was performed in 26 limbs and the remaining 22 limbs required urgent or emergent treatment after aneurysm thrombosis (16) or embolic digital ischemia (six). Retrospective review of preoperative and intraoperative arteriograms and CT or ultrasound scans was done to define the relationship of distal runoff anatomy to initial symptoms and long-term grafting success during a mean follow-up of 48 months. Only five of 48 limbs (10%) had three continuous tibial vessels and a patent pedal arch. Twenty-six limbs (55%) had one or no named calf vessels and 11 limbs had incomplete pedal arches. When thrombosis or symptomatic embolism occurred, the anatomy was significantly worse; 15 of 22 such limbs (68%) had one or no patent tibial vessels and seven had incomplete pedal arches. Nineteen of 28 aneurysms examined by CT or ultrasound scanning showed intraluminal thrombus. Eight of 13 patent aneurysms with intraluminal thrombus had one or no patent tibial vessels. The 5-year graft patency rate was 74% for the entire study group. Bypass for repair of asymptomatic aneurysms had a patency rate of 91% at 5 years vs 54% for symptomatic patients (p less than 0.05). Patients with popliteal aneurysms often have advanced tibial disease that appears worse in those with symptoms. The occurrence of a patent popliteal aneurysm with intraluminal thrombus and advanced runoff disease suggests that chronic microembolism may be an etiologic factor in the tibial disease observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Technical defects as a cause of early graft failure after femorodistal bypass.

Technical defects threaten the early patency of infrainguinal bypass grafts. We reviewed 849 cases of femorodistal bypass to determine the incidence of technical graft failure, as well as other causes of early graft occlusion. The efficacy of adjunctive intraoperative arteriography was assessed. Early graft failure occurred in 62 (7.3%) cases and was due to technical defects in nine (14.5%) cases. Embolization caused early failure in six (9.7%) cases, coagulation disorders caused occlusion in ten (16.1%) cases, and failure was due to inadequate runoff in seven (11.3%) cases. No identifiable cause of graft thrombosis was found in 30 (48%) cases, but thrombectomy and empiric anticoagulation therapy salvaged 25 of these grafts. Intraoperative arteriography was very specific (98%) and moderately sensitive (76%) for the detection of technical defects in this series. Technical defects appear not to be the most common cause of early infrainguinal bypass graft failure and were found in only 1% of all cases reviewed. Critical attention must be given to other causes, such as emboli, and particularly to disorders of the host coagulation system that may threaten the success of the procedure.

Angiography↗
PubMed1987

The reoperative potential of infrainguinal bypass: long-term limb and patient survival.

The present study reviews the fate of patients undergoing reoperation after failure of infrainguinal bypass grafts. During a 10-year period, 202 patients with failed distal bypass grafts had 389 infrainguinal reoperative procedures, an average of 1.9 reoperations per patient. Including the initial procedure and subsequent reoperations, a total of 591 operations were performed in this group. Secondary bypass was performed in 101 patients, a tertiary procedure in 51, a fourth bypass in 30, and more than four operations were required in 20 patients. Reoperation was performed to treat severe ischemia (rest pain, ulceration, or gangrene) in 377 of 389 cases (97%). Repetitive bypass was performed with autogenous vein in 21 cases (7.4%), composite grafts in 16 patients (5.6%), and polytetrafluoroethylene in 247 cases (87%). The remaining 105 reoperations were thrombectomy in 77 cases, thrombectomy plus distal angioplasty in 20 cases, and profundaplasty in eight cases. The distal anastomosis was to the popliteal artery in 14% of reoperative cases and to the tibial or peroneal artery in 59%. Mean follow-up for all patients was 70 months. Four operative deaths occurred in 389 reoperations (1.0%), and there were 35 late deaths. The cumulative life-table 5-year survival rate for all patients was 80%. The operative morbidity rate was 12.3%, including wound infection in 3.1% and hematoma in 6.4%. Sixty-seven cases required major amputation, below-knee in 48 (72%) and above-knee in 19 (28%). The 5-year limb salvage rate was 59%. Cumulative graft patency was 37% at 5 years. The 80% 5-year survival rate may reflect aggressive management of associated carotid and coronary artery disease. The demonstrated long survival indicates that recurrent ischemia after distal bypass failure requires attention. In this study, re-operation provided long-term limb salvage in most cases without significant compromise in patient safety or amputation level if amputation was required.

Amputation, Surgical↗
PubMed1986

Descending thoracic aorta-to-femoral artery bypass.

Descending thoracic aorta-to-femoral artery grafts were placed in 13 patients who had abdominal aortas deemed undesirable for surgical treatment. These included seven patients in whom an infected aortic graft had been removed for primary graft infection (three) or aortoduodenal fistula (four). These patients had been treated initially with axillary-femoral grafts. In five other patients, this approach was used following failure of at least two previous aortofemoral grafts. The remaining patient was so treated following multiple complex abdominal operations. The surgical technique involves a posterolateral, seventh interspace thoracoabdominal incision with a transdiaphragmatic retroperitoneal tunnel to the left groin. There was no operative mortality. The mean follow-up of all patients was 22 months (range, one to 44 months). All grafts remained patent except one, which was removed because of ascending groin infection. Three patients died, at 24, 29, and 44 months postoperatively, respectively. Reasonable perioperative morbidity and reliable patency make this an attractive technique for the conversion of axillofemoral bypasses and, when reentry of the abdominal cavity is undesirable, laparotomy is avoided.

Aorta, Thoracic↗
PubMed1986

Six-year prospective multicenter randomized comparison of autologous saphenous vein and expanded polytetrafluoroethylene grafts in infrainguinal arterial reconstructions.

Autologous saphenous vein (ASV) and polytetrafluoroethylene (PTFE) grafts were compared in 845 infrainguinal bypass operations, 485 to the popliteal artery and 360 to infrapopliteal arteries. Life-table primary patency rates for randomized PTFE grafts to the popliteal artery paralleled those for randomized ASV grafts to the same level for 2 years and then became significantly different (4-year patency rate of 68% +/- 8% [SE] for ASV vs. 47% +/- 9% for PTFE, p less than 0.025). Four-year patency differences for randomized above-knee grafts were not statistically significant (61% +/- 12% for ASV vs. 38% +/- 13% for PTFE, p greater than 0.25) but were for randomized below-knee grafts (76% +/- 9% for ASV vs. 54% +/- 11% for PTFE, p less than 0.05). Four-year limb salvage rates after bypasses to the popliteal artery to control critical ischemia did not differ for the two types of randomized grafts (75% +/- 10% for ASV vs. 70% +/- 10% for PTFE, p greater than 0.25). Although primary patency rates for randomized and obligatory PTFE grafts to the popliteal artery were significantly different (p less than 0.025), 4-year limb salvage rates were not (70% +/- 10% vs. 68% +/- 20%, p greater than 0.25). Primary patency rates at 4 years for infrapopliteal bypasses with randomized ASV were significantly better than those with randomized PTFE (49% +/- 10% vs. 12% +/- 7%, p less than 0.001). Limb salvage rates at 3 1/2 years for infrapopliteal bypasses with both randomized grafts (57% +/- 10% for ASV and 61% +/- 10% for PTFE) were better than those for obligatory infrapopliteal PTFE grafts (38% +/- 11%, p less than 0.01). These results fail to support the routine preferential use of PTFE grafts for either femoropopliteal or more distal bypasses. However, this graft may be used preferentially in selected poor-risk patients for femoropopliteal bypasses, particularly those that do not cross the knee. Although every effort should be made to use ASV for infrapopliteal bypasses, a PTFE distal bypass is a better option than a primary major amputation.

Actuarial Analysis↗
PubMed1986

Surgical treatment of venous obstruction and insufficiency.

Direct venous reconstruction is being applied to patients with chronic venous stasis disease. Crosspubic bypass and saphenopopliteal bypass have proved to be satisfactory procedures whereas valve reconstructions by valvuloplasty, segment transfer, and autotransplantation are being explored. These procedures add to the surgeon's armamentarium in dealing with chronic venous stasis disease.

Blood Vessel Prosthesis↗
PubMed1986

Result of bypass grafting for upper limb ischemia.

Bypass grafting in the treatment of upper extremity ischemia is required far less frequently than it is in the lower extremity. The present study was undertaken to evaluate functional results and long-term patency of such grafts. Between 1978 and 1984, 33 bypass grafts were performed to relieve hand and forearm ischemia in 27 patients. The indication for bypass was neglected trauma (violent or iatrogenic) in 12 cases, primary arteriopathy in nine patients, and vascular complications of thoracic outlet compression in six patients. A reversed saphenous vein graft was used in 22 cases, and polytetrafluoroethylene was used in the remaining 11 procedures. Proximal anastomoses were from the aortic arch (one), subclavian artery (five), axillary artery (11), carotid artery (seven), and brachial artery (nine). Distal reconstructions were to the subclavian (three), axillary (three), brachial (16), radial (four), ulnar (two), and interosseous (five) arteries. Complete pre- and postoperative Doppler pressure measurements were available in 19 cases and demonstrated a significant increase in forearm systemic pressure index, from 0.51 before bypass to 0.86 postoperatively (p less than 0.001). Finger systolic pressure measurement in 10 patients also showed a significant improvement after operation. Follow-up of 31 grafts from 6 to 72 months (mean, 35.5 months) revealed an overall patency rate of 73% at 2 years and 67% at 3 years. Similar to lower extremity revascularization, more proximal grafts fared better; the 2-year patency rate was 83% for grafts at or above the brachial artery but only 53% for bypass distal to the brachial bifurcation. Major amputation was not required in any case, even after graft occlusion.

Adolescent↗
PubMed1986

Extended use of computed tomography in the management of complex aortic problems: a learning experience.

Eighty-nine patients with clinical problems arising from the thoracic or abdominal aorta had computed tomography (CT) scans with contrast enhancement in addition to standard aortograms. Forty-four patients had aneurysms, 22 had aortic graft complications, and 23 had aortoiliac occlusion. CT scanning provided diagnostic information not apparent by conventional angiography in 39 patients (43.8%). This additional information did not significantly alter the operative management in 13 patients (14.6%). The helpful information provided by CT in these patients included demonstration of gallstones, renal cysts, anomalous venous structures, horseshoe kidney, and femoral anastomotic aneurysms. However, in 26 of 89 patients (29%), the additional data obtained by CT significantly changed the timing or approach to operative management. Management was altered in 12 of 44 patients (28%) with aneurysms, 7 of 22 patients (32%) with aortic graft complications, and 7 of 23 patients (30%) with aortoiliac occlusive disease or suspected distal thromboembolism. Specific information provided by CT included contained aortic aneurysm rupture, aortic dissection, laminated intraluminal thrombus or pseudointima, extent of perigraft infection, aortic atherosclerosis, anastomotic false aneurysm, and thrombus as a source of distal embolization. Thus, CT had a significant impact on operative management. It serves as a valuable adjunct to aortography in patients with complex aortic problems.

Aged↗
PubMed1986

Popliteal artery entrapment: diagnosis by computed tomography.

Popliteal artery entrapment by an anomalous band of the gastrocnemius muscle is uncommon. In cases where popliteal artery occlusion has occurred, the diagnosis is difficult to establish. A case is presented in which computed axial tomography of the popliteal space established the diagnosis of popliteal artery thrombosis caused by entrapment when other diagnostic modalities were inconclusive. Computed axial tomography provides precise anatomic display of the muscle structure of the popliteal fossa and should be an important diagnostic tool in patients suspected to have popliteal artery entrapment.

Adult↗