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Biomedical subjects

J M Porter

Publications and source records attributed to J M Porter.

At least 109 records · Page 6Linked to original sources

Comparison of axillofemoral and aortofemoral bypass for aortoiliac occlusive disease.

PURPOSE: A comparison of aortofemoral bypass grafting (AOFBG) and axillofemoral bypass grafting (AXFBG) for occlusive disease performed by the same surgeons during a defined interval forms the basis for this report. METHODS: Data regarding all patients who underwent AOFBG of AXFBG for lower-extremity ischemia caused by aortoiliac occlusive disease were prospectively entered into a computerized vascular registry. The decision to perform AOFBG rather than AXFBG was based on assessment of surgical risk and the surgeon's preference. This report describes results for surgical morbidity, mortality, patency, limb salvage, and patient survival for procedures performed from January 1988 through December 1993. RESULTS: We performed 108 AXFBGs and 139 AOFBGs. AXFBG patients were older (mean age, 68 years compared with 58 years for AOFBG, p<0.001), more often had heart disease (84% compared with 38%, p<0.001), more often underwent surgery for limb-salvage indications (80% compared with 42%, p<0.001). No significant differences were found in operative mortality (AXFBG, 3.4%; AOFBG, <1.0%, p=NS), but major postoperative complications occurred more frequently after AOFBG (AXFBG, 9.2%; AOFBG, 19.4%; p<0.05). Follow-up ranged from 1 to 83 months (mean, 27 months). Five-year life-table primary patency, limb salvage, and survival rates were 74%, 89%, and 45% for AXFBG and 80%, 79%, and 72% for AOFBG, respectively. Although the patient survival rate was statistically lower with AXFBG, primary patency and limb salvage rates did not differ when compared with AOFBG. CONCLUSION: When reserved for high-risk patients with limited life expectancy, the patency and limb salvage results of AXFBG are equivalent to those of AOFBG.

Adult↗

Results of bypass to the popliteal and tibial arteries with alternative sources of autogenous vein.

PURPOSE: The goal of an all-autogenous policy for infrainguinal arterial bypass requires that many bypasses be performed with alternative autogenous veins (AAV) because an adequate length of ipsilateral or contralateral greater saphenous vein (GSV) is not available. The durability and efficacy of infrainguinal vein bypasses constructed of venous conduits other than a single segment of greater saphenous vein (SSGSV) is, however, questioned. METHODS: AAV and GSV bypasses were reviewed from 1980 through 1994. Patients who required bypass to the popliteal or a tibial artery were compared for vascular surgical history and vascular disease risk factors and life-table survival. AAV and SSGSV procedures were compared for indications for surgery, morbidity and mortality rates, limb salvage rates in patients who underwent surgery for limb-salvage indications, subsequent need for revision, and life-table-assisted primary patency. RESULTS: Nine hundred nineteen autogenous vein bypasses were performed to the popliteal or a tibial artery--187 (20%) with AAVs, including whole or partial arm vein conduits in 144 grafts (77%). One hundred fourteen AAVs (61%) required vein splicing. The mortality rate was 2% for SSGSV bypasses and 1% for AAV bypasses. The morbidity rate was higher for GSV surgery as a result of increased wound complications (11% vs 5%; p=0.02). Sixty-seven percent of patients with AAV bypass extremities had undergone previous ipsilateral arterial surgery, compared with 20% of patients with SSGSV bypasses (p0.0005). AAV bypasses were more likely to be to a tibial artery (71% vs 45%; p<0.0001). Twelve percent of SSGSV and 15% of AAV popliteal bypasses required revision (p=NS). The 5-year assisted primary patencies were 82%, 77%, and 63%, with limb salvage rates of 91%, 86%, and 74% for ipsilateral SSGSV, contralateral SSGSV, and AAV femoropopliteal bypasses, respectively. Twelve percent of SSGSV and 30% of AAV tibial bypasses required revision (p=0.0001). The 5-year assisted primary patencies were 74%, 82%, and 72%, with limb salvage rates of 84%, 92% and 78% for ipsilateral SSGSV, contralateral SSGSV, and AAV femorotibial bypasses, respectively. CONCLUSION: AAV bypasses can provide overall results comparable with SSGSV bypasses.

Aged↗

Diagnostic laparoscopy and laparoscopic transdiaphragmatic pericardial window in a patient with an epigastric stab wound: a case report.

Stab wounds to the abdomen can present a diagnostic dilemma to the trauma surgeon, especially in the thoracoabdominal region. Patients with lower chest and upper abdominal stab wounds are at risk for both intraabdominal and cardiac injury. Current options in the evaluation of these patients include mandatory laparotomy, diagnostic peritoneal lavage, thoracoscopy, sonography, and observation. Each has its own inherent advantages and disadvantages, but none of them represents the gold standard. Herein is reported a case of a patient with an epigastric stab wound who underwent diagnostic laparoscopy and laparoscopic transdiaphragmatic pericardial window to rule out both peritoneal penetration and cardiac injury.

Abdominal Injuries↗

Synovial cyst formation complicating total hip arthroplasty: a case report.

The most frequent causes of unilateral limb swelling unrelated to trauma or surgery are deep venous thrombosis, chronic venous insufficiency, and primary lymphedema. Other important but less frequent causes include infection and neoplasm. Neoplasms may cause limb swelling, either by soft tissue enlargement or incidental compression of venous or lymphatic structures. Reported here is an unusual case of a patient with unilateral leg swelling and an inguinal mass presenting years after total hip arthroplasty. The unilateral leg swelling was caused by compression of the right common femoral vein by a synovial cyst arising from the hip joint. Although only 2 cases have been described in the literature, such cyst formation is not uncommon with loose acetabular components. The most apparent cause of cyst formation was polyethylene debris. Treatment efforts should be directed at the source of the debris intraarticularly.

Female↗

The case against the conservative nonresectional management of infected prosthetic grafts.

The perception that there is an expanding role for conservative management of patients with aortic graft infection is unfounded. There is,in fact, a striking paucity of convincing data indicating that outcome following nonresectional therapy for aortic prosthetic graft infection is equivalent to modern-day results utilizing extra-anatomic bypass and graft excision. Drainage with localized antibiotic irrigation and biologic coverage may be attempted in unusual circumstances such as the unfortunate patient with an infected thoracoabdominal aortic graft, in whom graft excision is not feasible. A truly noteworthy development in the treatment of aortic graft infection over the past decade has been the remarkable improvement in results utilizing remote bypass and standard excisional therapy with perioperative mortality and amputation rates less than 10%. In our opinion this approach remains the best and safest option.

Anti-Bacterial Agents↗

Study of an acoustic technique to detect cavitation produced by a tilting disc valve.

BACKGROUND AND AIM OF THE STUDY: Transient cavitation has been directly observed near operating mechanical heart valves in vitro and inferred in vivo via the observation of pitting on explanted clinically used valves. Visual detection of cavitation bubbles, however, cannot be accomplished in vivo or when any opaque fluid, e.g. blood, is used. METHODS: This study examines a passive acoustic technique for detecting cavitation caused by a 27 mm tilting disc valve. We captured, valve closing sounds in vitro and attempted to detect a shift of energy into higher frequencies due to emission of broad-band noise caused by collapsing bubbles. The valve tester consists of a piston pump which directly drives the valve, a 16 cm diameter cylindrical lucite atrium and an air chamber in parallel to provide compliance. Water was used as a blood analog fluid. The cycle rate was altered to vary valve loading and produce cavitation. Acoustic signals were detected by a miniature hydrophone and a large area transducer and the waveforms were spectrum analyzed to 200 kHz and 500 kHz respectively. Cavitation onset was determined rising a high speed video camera. RESULTS: It was found that even under non-cavitating conditions, significant energy was produced at frequencies greater than 100 kHz, and this energy increased with increased load. The proportion of energy in high frequency bands, however, remained fairly constant when cavitation was not present and began to rise only after the cavitation threshold was reached. To isolate cavitation as an independent variable, data were taken with all system parameters constant, but using water under two different conditions. Degassed 17 degrees C water produced no visualizable bubbles, while aerated tap water at 43 degrees C showed a high degree of cavitation. CONCLUSIONS: The results indicate that cavitation, while causing a shift of energy to higher frequencies, is not the only mechanism responsible for the shift of energy into higher frequencies.

Acoustics↗

Current management of Raynaud's syndrome.

Raynaud's syndrome affects 20% to 25% of the population in cool, damp climates. Although its etiology and pathophysiology are poorly understood, treatment options do exist. For mild cases, the wearing of gloves, cold avoidance, tobacco cessation, and assurance that this is a nuisance condition that will not lead to finger amputation are often all that is required. Patients who fail this protocol are treated with extended-release nifedipine, 30 mg, at bedtime. In our experience, 70% to 80% respond with a decrease in severity and frequency of attacks, but 20% to 50% develop intolerable side effects. If nifedipine fails, we consider another calcium-channel blocker, an ACE inhibitor, or Dibenzyline. Biofeedback is offered to patients, but in our experience few are interested. Patients with digital ulceration are treated with nifedipine, pentoxifylline, and antibiotics as needed. We recommend soap-and-water washes and either a damp dressing or Silvadene cream. If there is chronic non-healing or intractable pain, we have on occasion performed a fingertip amputation. Although these do not tend to heal promptly, they generally do heal with time and provide excellent pain relief. We have not performed upper extremity sympathectomy for nonhealing finger ulcers in more than 20 years.

Angiotensin-Converting Enzyme Inhibitors↗

Reducing perioperative myocardial infarction following vascular surgery. The potential role of beta-blockade.

OBJECTIVE: To determine which perioperative variables may influence the occurrence of perioperative myocardial infarction (PMI) following vascular surgery. DESIGN: Case-control study. SETTING: Combined Veterans Affairs Medical Center-university hospital vascular service. PATIENTS: During a 4-year period, all major vascular surgical operations (N = 2088) were evaluated with serial postoperative electrocardiography and cardiac enzyme measurements. Patients with PMI following nonemergent vascular surgery (N = 53) were matched with randomly selected control patients without PMI (N = 106) for age, gender, type of operation, hypertension, and symptoms of coronary artery disease. MAIN OUTCOME MEASURES: The two groups were compared for operative blood loss, blood pressure, and heart rate as well as length of operation, type of anesthetic, and use of perioperative beta-blockers, nitroglycerine, calcium channel blockers, vasopressors, and angiotensin-converting enzyme inhibitors. RESULTS: beta-Blockers were used less frequently in patients with PMI than in control patients without PMI (30% vs 50%; P = .01). Overall beta-blockade was associated with a 50% reduction in PMI (P = .03). Perioperative myocardial infarction was not associated with length of operation, type of anesthetic, blood pressure, or use of other medications. CONCLUSIONS: beta-Blockade is associated with a decreased incidence of PMI in patients undergoing vascular surgery. Prophylactic perioperative use of beta-blockers may decrease PMI in patients requiring major vascular surgery. A prospective randomized trial of beta-blockers in these patients appears to be warranted.

Adrenergic beta-Antagonists↗

Prevalence of asymptomatic carotid stenosis in patients undergoing infrainguinal bypass surgery.

BACKGROUND: The prevalence of asymptomatic carotid stenosis in patients with lower-extremity ischemia is unknown. This report represents the largest carotid screening program to date of patients undergoing leg bypass. DESIGN: Patients undergoing infrainguinal bypass from 1987 through 1993 on the vascular surgery service at Oregon Health Sciences University, Portland, underwent routine carotid duplex examinations to detect the presence of asymptomatic carotid stenosis. PATIENTS: During the study period, 352 patients underwent infrainguinal revascularization for ischemia, of whom 225 (64%) had no prior carotid surgery, carotid arteriography, or cerebrovascular symptoms. There were 117 men and 108 women, with a mean age of 67 years. The indication for surgery was limb salvage in 67% and claudication in 33% of patients. RESULTS: Sixty-four patients (28.4%) who required lower-extremity revascularization had hemodynamically significant asymptomatic carotid artery stenosis or occlusion; 12.4% had stenosis of 60% or greater, the qualifying level for randomization in the Asymptomatic Carotid Atherosclerosis Study. Based on these findings, eight patients with carotid stenosis of 80% or greater underwent elective carotid endarterectomy. There were no postoperative neurologic events in the 225 leg bypass patients. By multivariate logistic regression analysis, the presence of carotid bruit (P < .001) and the presence of rest pain (P = .006) were associated with carotid stenosis of 50% or greater. Limiting screening to patients with carotid bruit, limb salvage indications for surgery, and/or advanced age excluded significant numbers of patients with stenosis; thus, these were not effective screening strategies. CONCLUSION: Screening carotid duplex scanning is indicated in patients who require lower-extremity revascularization.

Aged↗

Usefulness of fasting and postprandial duplex ultrasound examinations for predicting high-grade superior mesenteric artery stenosis.

PURPOSE: A fasting duplex ultrasound examination of the superior mesenteric artery (SMA) accurately detects high-grade (> 70%) stenosis. It has been postulated that postprandial mesenteric duplex scanning may further stratify stenosis and improve the ability of a fasting examination to detect a high-grade stenosis. We performed fasting and postprandial duplex scanning of 25 healthy controls and 80 patients with vascular disease undergoing aortography to determine whether postprandial mesenteric duplex scanning provides information beyond a fasting study alone. METHODS: Patients with vascular disease were divided into three groups based on lateral aortography results: group 1, 0% to < 30% SMA stenosis (n = 61); group 2, 30% to < 70% stenosis (n = 10); and group 3, 70% to 99% stenosis (n = 9). Fasting mesenteric duplex scanning was defined as positive for 70% to 99% stenosis if the peak systolic velocity (PSV) was > or = 275 cm/s. The ability of either fasting or postprandial mesenteric duplex scanning, and their combination, to predict high-grade (70% to 99%) SMA stenosis was determined using angiographic control. RESULTS: Mean fasting SMA PSV did not differ among controls and groups 1 and 2. Postprandial PSV increased significantly in all groups, but was not different among controls and groups 1 and 2. Mean fasting PSV was significantly higher, and the postprandial increase in PSV significantly lower, in group 3 compared with controls and with groups 1 and 2. Fasting mesenteric duplex scanning predicted 70% to 99% SMA stenosis, with 89% sensitivity, 97% specificity, 80% positive predictive value, 99% negative predictive value, and 96% accuracy. Corresponding values for postprandial scanning were 67%, 94%, 60%, 96%, 91%, and for the combination of normal fasting and postprandial scanning 67%, 100%, 100%, 96%, 96%, respectively. CONCLUSION: Postprandial increases in SMA PSVs are blunted in patients with high-grade stenosis, but feeding velocities do not stratify between lesser degrees of stenosis. Both fasting and postprandial PSVs identify high-grade (> 70%) stenosis. Their combination marginally improves fasting duplex scan specificity and positive predictive value. Postprandial scanning is not necessary for the diagnosis of high-grade stenosis if a fasting study identifies a PSV > or = 275 cm/s. The combination of normal fasting and postprandial mesenteric duplex ultrasound scanning may effectively rule out high-grade SMA stenosis.

Adolescent↗

Upper extremity thromboembolism caused by occlusion of axillofemoral grafts.

BACKGROUND: The axillofemoral bypass graft (AxFG) is increasingly accepted as treatment for lower extremity ischemia caused by aortoiliac occlusive disease in high-risk patients. The incidence of upper extremity (UE) thromboembolism caused by occlusion of an AxFG and the results of treatment form the basis for this report. METHODS: From 1984 to the present, all patients undergoing axillofemoral bypass grafting were followed up in a vascular registry. A standardized operative technique, using an externally supported 8-mm polytetrafluoroethylene graft, was used in performing 202 AxFGs in 182 patients. UE thromboembolism caused by occlusion of an AxFG was identified by retrospective patient record review. RESULTS: Occlusion of an AxFG occurred in 20 patients. Fifteen patients (75%) underwent immediate revision of the occluded graft. Two patients (10%) developed UE thromboembolism simultaneous with graft occlusion. One of these patients had immediate revision of the graft, and 1 had brachial embolectomy only. This patient and 4 others (25%) had the occluded AxFG left in place. Four of these 5 patients (80%) developed UE thromboembolism at 26 days, 2 years, 5 years, and 7 years, respectively, after occlusion. Overall, six UE thromboembolic complications occurred in 5 patients. CONCLUSIONS: UE thromboembolism represents a significant and specific complication of occluded AxFGs in our series (2.7% of patients, 25% of occluded grafts). It may be prudent to prophylactically detach the axillary portion of the graft and repair the axillary artery in patients who do not require immediate revision of an occluded AxFG.

Algorithms↗

Diagnosis and long-term clinical outcome in patients diagnosed with hand ischemia.

PURPOSE: The long-term clinical outcome of patients diagnosed with digital artery obstruction and symptomatic hand ischemia is largely unknown. Our long-term experience with the diagnosis of symptomatic digital artery obstruction and the long-term natural history of this condition forms the basis for this report. METHODS: From 1971 to 1985, 44 patients with symptomatic hand ischemia and palmar or digital arterial obstruction underwent arteriography and digital photoplethysmography (PPG). Patients were grouped according to severity of hand ischemia symptoms, including ulceration and digital amputation and the presence of a connective tissue disease (CTD). Arteriography was compared with PPG by creating an objective severity scale (digital obstruction index [DOI]). RESULTS: Average follow-up was 15.2 years (range 10 to 22 years). Initially 21 patients (48%) had moderate symptoms, and 23 patients (52%) had severe symptoms of hand ischemia. Follow-up symptoms in 28 patients improved (13 of 26 with CTD, 15 of 18 without CTD), in 15 patients (12 of 26 with CTD, 3 of 18 without CTD) remained unchanged, and in only 1 patient (1 of 26 with CTD) worsened. Seventeen (65%) patients with CTD (n = 26) had development of one or more ulcers, and six (24%) underwent one or more digital amputations. Four (22%) patients without CTD (n = 18) had finger ulceration (p < 0.012 compared with patients with CTD), and one patient (6%) underwent subsequent digital amputation (p = NS). The arteriography-DOI and PPG-DOI were equally accurate in determining severity of finger ischemia as manifested by severity of symptoms or ulcer development. CONCLUSIONS: The favorable long-term prognosis of symptomatic finger artery occlusion described herein mandates the avoidance of premature finger amputation. Patients with CTD fare worse, but even in this group tissue loss is modest. Finger PPG is as accurate as arteriography for determining severity of hand ischemia.

Adolescent↗

Progression of atherosclerosis in arteries distal to lower extremity revascularizations.

PURPOSE: The characteristics of progression of atherosclerotic occlusive disease (AOD) of the lower extremities after revascularization are unknown. Duplex scanning or angiography were used to determine progression in 150 patients after they underwent revascularization for AOD. METHODS: Follow-up studies were compared with presurgical arteriograms. Superficial femoral (SFA) and popliteal arteries were graded as less than 50% stenosis, 50% to 99% stenosis, or occluded. Tibial arteries were graded with regard to whether they were continuously patent from the popliteal trifurcation to the ankle. Progression was defined as an increase in one stenosis category. RESULTS: At a mean follow-up of 4.8 years, 18% of native arteries, 39% of extremities, and 52% of patients demonstrated progression of AOD. Overall, 21% of arteries in patients undergoing infrainguinal bypass and 14% of arteries in patients undergoing suprainguinal bypass demonstrated progression (p = 0.004). Progression was more frequently detected in examinations performed more than 4 years after baseline arteriography (66%) than in examinations performed 6 months to 2 years (45%, p = 0.032) or 2 to 4 years (44%, p = 0.029) after baseline arteriography. Thirty percent of SFAs demonstrated progression, and 32% with 50% stenosis or greater at baseline became occluded. There was no difference in SFA, popliteal, or tibial artery progression in revascularized versus nonrevascularized extremities after suprainguinal bypass. There was no difference in tibial artery progression in operated and nonoperated limbs after femoropopliteal artery bypass. CONCLUSIONS: AOD progression occurs frequently in patients requiring revascularization and is more prevalent in patients requiring femoropopliteal than in patients requiring suprainguinal bypass. AOD progression in patients undergoing vascular surgery is associated with the pattern of disease producing lower extremity ischemia and does not appear to be worsened by arterial reconstruction.

Adult↗

Do normal early color-flow duplex surveillance examination results of infrainguinal vein grafts preclude the need for late graft revision?

PURPOSE: Optimal duration of postoperative duplex surveillance of infrainguinal vein grafts is not known. Previous reports have suggested nearly all vein graft stenoses are present within the first postoperative year, and normal duplex examination results during this time eliminate the need for ongoing graft surveillance. To determine whether surveillance may be safely discontinued in patients with normal early postoperative surveillance studies, we reviewed the color-flow surveillance examinations in our patients who underwent infrainguinal reverse vein graft revisions during a 4 1/2 year period. METHODS: Clinical and vascular laboratory records were reviewed of all patients who underwent infrainguinal reverse vein bypass grafting followed by subsequent graft revision for a duplex scanning-detected abnormality at our institution between January 1990 and July 1994. RESULTS: Of 447 infrainguinal reverse vein bypasses performed, 36 (8.1%) underwent surgical revision as a result of an abnormal finding during routine duplex surveillance. The initial postoperative duplex examination was obtained within 2 weeks of graft implantation in 23 (64%) patients, between 2 weeks and 3 months in 10 (28%) patients, and between 3 and 6 months in three (8%) patients. Duplex abnormalities prompting revision included 11 (31%) grafts with a mid-graft peak systolic velocity (PSV) < or = 45 cm/sec, 23 (64%) grafts with a focal PSV > or = 200 cm/sec, one graft with a PSV > or = 150 cm/sec but < 200 cm/sec, and one thought to be occluded by duplex but found to be patent by angiography. Abnormal duplex findings were initially detected within 2 weeks of graft implantation in five (14%) patients, between 2 weeks and 3 months in eight (22%) patients, from 3 to 6 months in 12 (33%) patients, from 6 to 12 months in six (17%) patients, and > 1 year in five (14%) patients. In only 25% of cases were mid-graft PSVs < or = 45 cm/sec or focal velocities > or = 200 cm/sec identified on the initial examination; 75% were found during subsequent surveillance. CONCLUSIONS: Although most reverse vein graft abnormalities detected by duplex surveillance and prompting graft revision appear within the first postoperative year, many are not detected on the initial examination. In our recent experience 31% of duplex abnormalities leading to vein graft revision were first detected more than 6 months after operation. Discontinuation of graft surveillance based on normal early findings will result in thrombosis of some vein grafts that may otherwise be salvaged.

Adult↗

Deep vein thrombosis associated with lower extremity amputation.

PURPOSE: Patients undergoing lower extremity amputation are perceived to be at high risk for deep vein thrombosis (DVT). Limited data are available, however, to confirm this impression. The purpose of this study is to prospectively document the incidence of DVT complicating lower extremity amputation. METHODS: During a recent 28-month period, 72 patients (71 men, 1 woman; mean age 68 years) undergoing major lower extremity amputation (31 above-knee and 41 below-knee) were prospectively evaluated with perioperative duplex scanning for DVT. RESULTS: DVT was documented in nine (12.5%) patients (one bilateral, four ipsilateral, and four contralateral to amputation). Patients with a history of venous disease were at significantly higher risk for development of DVT (p = 0.02). Thrombi were located at or proximal to the popliteal vein in eight patients and were isolated to the tibial veins in one patient. DVT was identified before operation in six patients and after operation in three. Patients with DVT were treated with heparin anticoagulation, with no patient experiencing clinical symptoms compatible with pulmonary embolism. CONCLUSIONS: In our recent experience, lower extremity amputation is associated with DVT at or proximal to the popliteal vein in 11% of patients. Documentation of DVT prevalence is essential to assist surgeons in planning a management strategy for prevention, diagnosis, and treatment of DVT associated with lower extremity amputation.

Aged↗

Reporting standards in venous disease: an update. International Consensus Committee on Chronic Venous Disease.

At the request of the Ad Hoc Committee on Reporting Standards of the Joint Council of the Society for Vascular Surgery and the North American Chapter of the International Society for Cardiovascular Surgery, this report updates and modifies "Reporting standards in venous disease" (J Vasc Surg 1988;8:172-81). As in the initial document, reporting standards for publications dealing with (1) acute lower extremity venous thrombosis, (2) chronic lower extremity venous insufficiency, (3) upper extremity venous thrombosis, and (4) pulmonary embolism are presented. Numeric grading schemes for disease severity, risk factors, and outcome criteria present in the original document have been updated to reflect increased knowledge of venous disease and advances in diagnostic techniques. Certain recommendations of necessity remain arbitrary. These standards are offered as guidelines whose observance will in our opinion improve the clarity and precision of communications in the field of venous disorders.

Acute Disease↗