Hope I die before I get old.
Explore the source record for details and available documents.
Anecdotes as Topic↗
Biomedical subjects
W R Flinn
Publications and source records attributed to W R Flinn.
Venous hemodynamics during impulse foot pumping.
PURPOSE: This study was designed to measure the effect of intermittent pneumatic compression of the plantar venous plexus on popliteal vein (PV) and common femoral vein (CFV) velocities measured by duplex ultrasound scanning. METHODS: Thirty lower limbs in 15 healthy volunteers had venous duplex scanning measurement of PV and CFV velocities before and during foot pumping with an arteriovenous impulse foot pump system. Venous velocities were measured at two pump pressure settings (100 mm Hg, 200 mm Hg) and during two pump impulse durations (short = 1 second, normal = 3 seconds). All limbs were examined with the subjects in the supine position, and then measurements were repeated with subjects in the 15-degree reverse Trendelenburg position. The mean maximum venous velocity (MVV) produced by foot pumping was compared with resting venous velocity at each anatomic location and for each technologic variable. RESULTS: Impulse foot pumping produced a statistically significant increase in MVV in both the PV and the CFV compared with resting velocities. This significant increase was observed for both pressure settings and both impulse durations, and no differences produced by these two individual variables could be detected. The increase in MVV produced by foot pumping was similar for limbs in the supine position and those examined in the reverse Trendelenburg position. The percentage increase in MVV produced by foot pumping was significantly higher in the PV than in the CFV. CONCLUSIONS: Intermittent pneumatic compression of the plantar venous plexus produces measurable increases in venous outflow from the lower limbs of normal subjects. This study seems to justify further evaluation of the effectiveness of this technique for mechanical deep venous thrombosis prophylaxis in selected high-risk patient groups.
Adult↗
Salvage of renal allograft function and lower extremity venous patency with thrombolytic therapy: case report and review of the literature.
Five months after a cadaveric renal transplants a 69-year-old man was admitted with caval, iliac, and renal allograft vein thrombosis that occurred in the setting of a previously placed caval filter. The patient's urine output and renal function deteriorated rapidly. Thrombolytic therapy with urokinase was begun, and lysis of the thrombus occurred in 72 hours. The patient's renal function returned to baseline, and the transplant was salvaged. Moreover lower extremity venous patency and valvular function were maintained. We report the case and review the literature on thrombolytic therapy for renal allograft vein and lower extremity deep venous thrombosis.
Aged↗
Femorofemoral bypass for aortofemoral graft limb occlusion: a ten-year experience.
PURPOSE: Aortofemoral bypass (AFB) is a durable reconstruction; however, graft limb occlusion occurs in 10% to 20% of patients and results in limb ischemia. Treatment of AFB limb occlusion has been debated, but many recommended femorofemoral bypass (FFB). FFB grafts have had excellent patency rates. The durability of FFB specifically for AFB limb occlusion has not been reported. This study retrospectively examined a 10-year experience with FFB for AFB limb occlusion to determine FFB performance. METHODS: Between 1982 and 1992, FFB was performed on occluded AFB limbs in 22 patients (14 men and 8 women). Reoperation was performed for disabling claudication in five cases, but the remaining 17 patients (77%) had critical limb ischemia. FFB originated from the contralateral patent AFB limb in all cases. Distal anastomosis was to the common femoral artery (n = 8) or the profunda femoris (n = 14). FFB graft patency was confirmed by direct Doppler arterial examination over a mean follow-up of 47 months. RESULTS: The cumulative life-table primary patency rate of FFB was 54% at 5 years. Reoperative procedures performed in nine cases resulted in a secondary patency rate of 84% at 5 years. The limb salvage rate was also 84% at 5 years, reflecting the impact of successful reoperation. Major amputations (two below-knee, one above-knee) were necessary in only three cases. There were no perioperative deaths after FFB, and the cumulative 5-year survival rate was 77%. CONCLUSION: Aortic graft limb occlusion occurs less frequently than failure of infrainguinal grafts making the success of specific reoperative strategies difficult to document reliably. This study suggests that FFB is a safe and durable alternative for AFB limb failure. An aggressive policy of reoperation has resulted in successful extension of FFB graft function and an excellent rate of limb salvage.
Aged↗
Awake patient monitoring to determine the need for shunting during carotid endarterectomy.
BACKGROUND: The indications for shunt placement to prevent cerebral ischemia during carotid endarterectomy have been controversial. Some investigators have recommended empiric shunting for patients presumed to be at higher risk for cerebral ischemia with a recent stroke or severe stenosis or occlusion of the contralateral internal carotid artery. METHODS: Carotid endarterectomy was performed in 81 cases with cervical block anesthetic, monitoring the awake patient for the development of cerebral ischemia (unresponsiveness or paralysis) during carotid clamping. The need for shunting (based on awake response) was compared in patients with the arbitrarily defined empiric indications for shunting (n = 29) versus those who did not have such clinical or anatomic findings (n = 52). RESULTS: Cerebral ischemia requiring shunting was observed in five (17.2%) of 29 cases with the defined indications for empiric shunting. This was not different than the need for shunting in the control group where cerebral ischemia was seen in eight (15.4%) of 52 cases. No intraoperative neurologic events occurred in any case, but one (1.2%) patient suffered a postoperative transient ischemia attack and another (1.2%) had a postoperative stroke. CONCLUSIONS: Empiric clinical or anatomic indications for shunting were not reliable predictors of cerebral ischemia that developed during carotid clamping in this study. Awake patient monitoring during carotid endarterectomy with regional anesthetic allowed prompt, accurate identification of patients with cerebral ischemia who would clearly benefit from placement of a shunt.
Aged↗
Axillary-popliteal artery bypass provides successful limb salvage after removal of infected aortofemoral grafts.
Axillary-popliteal artery bypasses were placed to revascularize 28 extremities for 17 patients who were undergoing removal of infected aortofemoral grafts. Polytetrafluoroethylene (PTFE [polytef]) material was anastomosed to the above-knee popliteal artery in 22 cases and to the below-knee popliteal artery in six limbs. All but one patient had axillary-popliteal grafts in place before excision of the aortic graft. In 12 groins, vein-patch angioplasty was performed after removal of the infected aortic graft to provide retrograde pelvic perfusion and maintain femoral patency for future reconstruction. Three patients (18%) died of septic-related, multisystem organ failure. With a mean follow-up of 25 months, primary patency was 75% at 1 year and 43% at 2 years. Secondary patency, maintained by thrombectomy (n = 7), revision (n = 3), and conversion to warfarin sodium (Coumadin) therapy (n = 6) was 100% at 2 years, and limb salvage was achieved for all surviving patients.
Anastomosis, Surgical↗
Long-term evaluation of composite sequential bypass for limb-threatening ischemia.
When sufficient vein for a completely autogenous femorotibial artery bypass is not available, composite sequential grafting by using vein combined with polytetrafluoroethylene material is a surgical option. This study reviews what is currently the largest collection of these grafts and focuses on technical aspects and long-term patency characteristics. During a 7-year period 67 composite sequential bypasses were used to manage rest pain (38), ulcer (18), or gangrene (11) in 62 patients (mean age, 66 years). Fifty-two percent were men, and 51% had diabetes. This method was used as a primary reconstruction in 30, a second bypass in 16, and in 21 it was used after multiple other failed bypasses. Femoral to above-knee popliteal (44) and below-knee popliteal (23) 6 mm polytetrafluoroethylene grafts were placed. Then extensions of greater saphenous (57) or lesser saphenous (10) vein were anastomosed to the anterior tibial (19), posterior tibial (26), or peroneal (22) arteries. Fifty-three percent were maintained on long-term warfarin (Coumadin) anticoagulation, and 33% were maintained on aspirin. No deaths occurred in the perioperative period. Bypass patency was ascertained by a Doppler pressure and waveform analysis, with mean follow-up of patency or to the time of graft failure of 33 months (1 to 91 months). Three-year patient survival was 72%. Cumulative life-table primary patency of 72% (1-year), 64% (2-year), and 48% (3-year) was calculated. Two grafts are functioning 7 years after placement. Limb salvage was 84% at 2 years and 70% at 4 years. At the time of failure, five grafts retained a patent venous bypass segment, which allowed prompt reconstruction of the proximal portion. In a comparison of grafts with early failure and those with long-term patency, the SVS/ISCVS runoff score, vein diameter, tibial artery diameter, and coagulation status were similar. However, patients with the popliteal anastomosis above the knee had 2-year patency of 72% compared with 46% for those with below-knee anastomoses. This technique, when possible, appears preferable to an all prosthetic tibial bypass.
Adult↗
Acute aortic occlusion as a result of extrinsic compression from peritoneal encapsulation.
Acute aortic occlusion frequently occurs with catastrophic visceral, spinal, or lower extremity ischemia and is most often caused by embolic or thrombotic events in older individuals with known cardiovascular disorders. This case describes the rapid development of the clinical signs of acute aortic occlusion in a young and completely healthy individual. Aortic occlusion was produced by extrinsic compression of the juxtarenal aorta from a closed-loop small intestinal obstruction contained within a peritoneal encapsulation, an extremely rare intraabdominal developmental anomaly.
Acute Disease↗
Excimer laser-assisted femoral angioplasty: early results.
The ability to ablate atheroma without generating heat makes the excimer laser wavelength a promising intraluminal technique for the treatment of arterial occlusive disease. This series reviews a preliminary experience treating patients with superficial femoral arterial disease admitted with limb-threatening ischemia or claudication. Twenty-six diseased superficial femoral arteries (5 stenotic and 21 occluded) were treated in 23 consecutive patients. Patients with claudication (18) reluctant to undergo bypass or with limb-threatening ischemia (8) at extremely high risk for surgery were included. There were 10 men and 13 women with a mean age of 67 years. A 308 nm excimer laser with an over-the-wire catheter (19) or balloon-centered end-on catheter (7) was used followed by balloon angioplasty. Twenty-four procedures were performed percutaneously, and two were performed with the vessel open in the operating room. Technical success, defined as disobliteration confirmed by angiography and greater than 0.15 increase of the ankle/brachial index, was achieved in 15 of 26. Eleven of 21 occlusions (52%) and four of five stenoses (80%) were opened. Only two of 11 lesions longer than 10 cm were successfully treated. Unsuccessful attempts (technical failure) occurred in 11 of 26 patients and resulted in four elective and one emergency femoral-popliteal bypass. Five patients were discharged with their claudication unchanged, and one had an elective amputation. Six arterial perforations with three arteriovenous fistulas occurred, all resolved without operation. No unanticipated limb loss occurred. In the 15 successful cases, the mean ankle/brachial index increase was 0.34. Seven (47%) of these 15 remain patent with a mean follow-up of 9.5 months (1.5 to 14 months).(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Aneurysm or occlusive disease--factors determining the clinical course of atherosclerosis of the infrarenal aorta.
Atherosclerosis of the infrarenal aorta results in distinct clinical entities--aortoiliac occlusive disease (AOD) and abdominal aortic aneurysm (AAA). Although loss of collagen has been implicated in AAA, collagen accumulation plays a role in AOD. In vivo collagen-gene expression can be assessed using complementary DNA for collagen types I and III alpha-chains. The purpose of this study is to compare total collagen (type I + III) and collagen types I and III messenger RNA in AAA, AOD and normal aorta. Specimens were collected from the infrarenal aorta during operation for AOD (n = 7), AAA (n = 7), autopsy, or organ procurement (normal; n = 7). Northern transfer analysis of total RNA was used to compare mRNA levels for type I and III collagen. After preliminary extraction, specimens were hydrolyzed for hydroxyproline analysis used to calculate total collagen (type I + III). Relative levels of type I (pro-a1[1]) mRNA were greater in both AOD (0.77 +/- 0.35) and AAA tissue (0.94 +/- 0.24; p = 0.6) than in normal aorta (0.02 +/- 0.03). Type III (pro-a1[III]) mRNA levels were also greater in AOD (2.52 +/- 0.19; p = 0.09) and AAA tissue (3.15 +/- 1.3) than in normals (0.97 +/- 0.47). Total collagen concentration was increased in AOD (45.6% +/- 3.1% dry weight; p less than 0.05) but not AAA tissue (27.8% +/- 4%) when compared to normal aorta (34.7% +/- 2.3%). Collagen type I and III gene expression is greater in older, diseased aorta, yet collagen accumulated only in AOD. This implies a similar synthetic response in both AOD and AAA. Thus, proteolytic degradation in AAA appears to determine collagen content and possibly the clinical course of the atherosclerotic process.
Aged↗
A comparative study of intraoperative angioscopy and completion arteriography following femorodistal bypass.
A prospective comparison of the findings on standard completion arteriography with those seen using videoangioscopy was done following 49 cases of "femorodistal" bypass grafting in 47 patients. The two techniques were compared with respect to the detection of technical defects, modification of the surgical procedures, early graft patency (72 hours), and complications. Completion arteriography was specific (95%) but only moderately sensitive (67%) compared with angioscopy for detection of technical problems. Following angioscopy, significant alterations in the surgical procedure were noted in 5 (10%) of the 49 cases. Early graft failure occurred in 3 (6.1%) cases but none were identifiably due to technical problems. Four patients suffered postoperative myocardial infarctions, 2 (4.2%) of which were fatal; no patients had contrast-induced allergies or renal failure. Angioscopy was measurably more accurate for the detection of technical problems than completion arteriography, but offered little information about distal arterial anatomy that may have an impact on graft patency or the use of antithrombotic therapy.
Aged↗
Distal embolization as a presenting symptom of aortic aneurysms.
The records of 302 patients who underwent abdominal aortic aneurysm (AAA) repair between 1985 and 1990 were reviewed. Two hundred and forty-eight patients (82%) were asymptomatic, while 32 patients (11%) had ruptured aneurysms. During this period, 15 patients (5%) presented with distal embolization as the first manifestation of their AAA. The preoperative embolic event resulted in limb-threatening ischemia in 3 patients, digital ischemia in 11, and calf myonecrosis in 1. CT scan was performed in 14 of 15 patients demonstrating irregular, heterogeneous thrombus within the AAA. Only two of the AAAs were larger than 5 cm. Angiography demonstrated occlusive lesions but was not diagnostic for AAA in seven patients and resulted in three episodes of embolization. AAA was repaired with a tube graft in 4 patients while a bifurcated graft was required in 11 patients for aneurysmal (in 4 patients) and occlusive disease (in 7 patients) of the iliac arteries. All cases employed a transperitoneal approach, systemic heparin, and distal occlusion prior to aortic clamping. Complications included three major (below-knee) and five minor amputations, developing or worsening renal failure in five patients (33%), and death in two (13%). In comparison, mortality was 5% for elective repair and 66% for rupture during this same period. CT scan was safer and more informative than angiography. The morbidity of patients with AAA presenting with emboli is comparable with rupture. The risk of embolization does not correlate with size and indicates the potentially dangerous nature of small AAAs.
Aged↗
Duplex scanning for assessment of mesenteric ischemia.
The accurate diagnosis of mesenteric arterial occlusive disease has in the past required invasive examination, primarily arteriography. Recent innovations in duplex ultrasound scan technology have for the first time provided a method for the noninvasive assessment of the splanchnic circulation in man. Mesenteric duplex scanning has been used successfully to measure postprandial changes in celiac and superior mesenteric arterial blood flow as well as changes in visceral flow produced by other pharmacologic stimuli.
Arteriovenous Shunt, Surgical↗
Computed tomography for evaluation of arterial disease in the popliteal fossa.
The clinical details, arteriograms, and computerized tomographic (CT) scans of 28 patients with popliteal arteriopathies were reviewed retrospectively to determine the usefulness of CT for the diagnosis and treatment of these disorders. Arteriography diagnosed 70% and CT diagnosed 98% of the 45 popliteal disorders. Popliteal aneurysms were not detected by arteriography because of occlusion in seven (20%) patients and intraaneurysmal thrombus that produced no luminal compromise in two. Thrombus was identified by CT in 22 of 24 patient aneurysms and suspected as the source of digital embolization in 7. Graft aneurysms were identified by CT in two cases, but one was not detected by arteriography because of graft occlusion. Two mycotic aneurysms were identified, one by arteriography and not by CT because of misinterpretation of a periarterial hematoma. Popliteal entrapment was diagnosed by CT in three cases, and in two cases occlusion precluded diagnosis of entrapment by arteriography. Adventitial cystic disease was diagnosed accurately by CT in three cases, and in two there were no characteristic arteriographic abnormalities. In cases of entrapment and cystic disease, the CT findings allow the surgeon to plan his approach through a posterior incision, which in these two instances facilitates surgical technique. CT provides detail of the arterial wall, intraarterial contents, and surrounding musculoskeletal anatomy, all of which are useful for accurate evaluation of arterial disorders of the popliteal fossa.
Adult↗
Mesenteric flow velocity variations as a function of angle of insonation.
This study was designed to quantitate variations in duplex ultrasound arterial flow velocities (cm/sec) in the common carotid artery and the superior mesenteric artery that were produced by changes in the angle of pulsed Doppler insonation. Duplex scanning was used to measure peak systolic flow velocity and mean velocity at angles from 30 degrees to 80 degrees; individual measurements were made at 10-degree increments in both the common carotid artery and the superior mesenteric artery in normal subjects. Peak systolic velocity in the common carotid artery varied from 86 cm/sec at 30 degrees to 168 m/sec at 80 degrees. Over the same transducer angle variation mean velocity ranged from 28 to 53 cm/sec. Similar changes in the superior mesenteric artery flow velocities were observed by varying the angle of insonation, where peak systolic velocity varied from 108 cm/sec (30 degrees) to 280 cm/sec (80 degrees), and mean velocity ranged from 29 cm/sec (30 degrees) to 71 cm/sec (80 degrees). Measurements taken from 70 to 80 degrees produced the most dramatic deviation from those taken at 60 degrees. In the common carotid artery the 70- and 80-degree angles produced 14% and 59% increases, respectively, in peak systolic velocity and 16% and 63% increases, respectively, in mean velocity. In the superior mesenteric artery 70-degree and 80-degree angles produced 16% and 120% increases, respectively, in peak systolic velocity and 17% and 111% increases, respectively, in mean velocity. At 80 degrees the percent increases in measured flow velocities for the superior mesenteric artery were significantly greater than those for the common carotid artery.(ABSTRACT TRUNCATED AT 250 WORDS)
Analysis of Variance↗
Duplex venous scanning for the prospective surveillance of perioperative venous thrombosis.
A total of 361 patients undergoing a variety of major neurosurgical procedures were entered into a prospective surveillance program using duplex ultrasound scanning for detection of perioperative deep venous thrombosis (DVT). All patients had duplex scans of the major veins of both legs preoperatively, on the third and seventh postoperative days, and at weekly intervals thereafter if hospitalized. All patients received elastic stocking and intermittent mechanical calf compression. Perioperative DVT was diagnosed by duplex scan in 17 cases (4.7%); 2 cases were present preoperatively and the remaining 15 cases developed after surgery. Venography detected only one false-positive scan in this series. One patient with DVT died, but the postmortem examination revealed no pulmonary embolism. The results of serial venous scans were normal in 344 cases. There were no in-hospital pulmonary embolisms in any patient with normal venous scan results. Two patients (0.6%) with normal serial scan results had fatal pulmonary embolism 1 and 3 weeks after discharge. Duplex venous scanning was useful for prospective DVT surveillance of a high-risk group. The overall incidence of DVT (4.7%) is below that expected in such patients, suggesting the effectiveness of the program of prophylaxis. Scan results were reliable for therapeutic decisions and did not jeopardize patient safety.
Adolescent↗
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↗
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↗