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Biomedical subjects

J R Wheeler

Publications and source records attributed to J R Wheeler.

At least 37 records · Page 2Linked to original sources
PubMed1999

Subfascial perforator vein ablation: comparison of open versus endoscopic techniques.

PURPOSE: To compare the outcomes and complications of open (OSPS) versus endoscopic subfascial perforator surgery (SEPS) for treatment of chronic venous insufficiency. METHODS: Data were retrospectively collected on 25 patients who underwent 27 SEPSs from February 1996 to August 1997 and from 22 patients who underwent 29 OSPSs between March 1978 and May 1993. Outcomes were evaluated for postoperative complications, ulcer healing, recurrence, and venous dysfunction scores on the last follow-up for the SEPS group and at 1-year follow-up for the OSPS group. RESULTS: The 2 groups were similar in age, sex, history of previous venous surgery, healed or active ulcers, etiology, deep venous incompetency, pathophysiology, and venous refill times. Eighteen (90%) of 20 active ulcers in the SEPS group healed with recurrences in 5 (28%) limbs at 7.5 +/- 5.4-month follow-up. All 19 ulcers in the OSPS group healed, with recurrences in 13 (68%) limbs at 35 +/- 35-month follow-up. Clinical venous dysfunction scores showed significant improvement following SEPS (10.0 +/- 3.6 to 5.4 +/- 4.1, p < 0.001) and OSPS (10.0 +/- 3.2 to 6.7 +/- 3.6, p < 0.001) with no significant difference between groups. Both groups also had significant improvement in anatomical and disability scores. There was no postoperative mortality in either group. The OSPS group had significantly more wound complications (45%) than the SEPS group (7%) (p < 0.005). The hospital stay and readmission rate for wound problems were also higher in the OSPS group. CONCLUSIONS: The early outcome showed equal improvement in clinical venous dysfunction scores in the 2 groups, but with significantly fewer complications in the SEPS group. Although the long-term durability of the endoscopic approach has not been determined, the short-term results would favor SEPS for treatment of severe venous insufficiency when perforator incompetence is a significant component.

Blood Flow Velocity↗
PubMed1999

Financial and organizational determinants of hospital diversification into subacute care.

OBJECTIVE: To examine the financial, market, and organizational determinants of hospital diversification into subacute inpatient care by acute care hospitals in order to guide hospital managers in undertaking such diversification efforts. STUDY SETTING: All nongovernment, general, acute care, community hospitals that were operating during the years 1985 through 1991 (3,986 hospitals in total). DATA SOURCES: Cross-sectional, time-series data were drawn from the American Hospital Association's (AHA) Annual Survey of Hospitals, the Health Care Financing Administration's (HCFA) Medicare Cost Reports, a latitude and longitude listing for all community hospital addresses, and the Area Resource File (ARF) published in 1992, which provides county level environmental variables. STUDY DESIGN: The study is longitudinal, enabling the specification of temporal patterns in conversion, causal inferences, and the treatment of right-censoring problems. The unit of analysis is the individual hospital. KEY FINDINGS: Significant differences were found in the average level of subacute care offered by investor-owned versus tax-exempt hospitals. After controlling for selection bias, financial performance, risk, size, occupancy, and other variables, IO hospitals offered 31.3 percent less subacute care than did NFP hospitals. Financial performance and risk are predictors of IO hospitals' diversification into subacute care, but not of NFP hospitals' activities in this market. Resource availability appears to expedite expansion into subacute care for both types of hospitals. CONCLUSIONS: Investment criteria and strategy differ between investor-owned and tax-exempt hospitals.

Cross-Sectional Studies↗
PubMed1998

Managed care and technical efficiency in outpatient substance abuse treatment units.

This article examines (1) the extent to which managed care participation is associated with technical efficiency in outpatient substance abuse treatment (OSAT) organizations and (2) the contributions of specific managed care practices as well as other organizational, financial, and environmental attributes to technical efficiency in these organizations. Data are from a nationally representative sample survey of OSAT organizations conducted in 1995. Technical efficiency is modeled using data envelopment analysis. Overall, there were few significant associations between managed care dimensions and technical efficiency in outpatient treatment organizations. Only one managed care oversight procedure, the imposition of sanctions by managed care firms, was significantly associated with relative efficiency of these provider organizations. However, several organizational factors were associated with the relative level of efficiency including hospital affiliation, mental health center affiliation, JCAHO accreditation, receipt of lump sum revenues, methadone treatment modality, percentage clients unemployed, and percentage clients who abuse multiple drugs.

Ambulatory Care↗
PubMed1998

A comparison of surgery for neurogenic thoracic outlet syndrome between laborers and nonlaborers.

OBJECTIVE: To determine factors of outcome following surgical intervention for neurologic thoracic outlet syndrome (NTOS). METHODS: In a retrospective study of patients surgically treated for NTOS, outcome was evaluated by postoperative symptoms and the ability of patients to return to work. RESULTS: Good, fair, and poor results were obtained in 26 (48%), 21 (39%), and 7 (13%) patients, respectively. The best predictor of a good outcome was occupation. Nonlaborers were more likely to have good outcome (21 of 32, 66%) when compared with laborers (5 of 22, 23%; P = 0.0025). Only 6 of 20 (30%) laborers were able to return to their original occupation compared with 17 of 26 (65%) nonlaborers (P = 0.036). CONCLUSIONS: Laborers with NTOS are less likely to have a good result from surgical intervention, are unlikely to return to their original occupation, and may require retraining for a non-labor-intensive occupation if they cannot return to their original work.

Analysis of Variance↗
PubMed1997

Long-term outcome after early infrainguinal graft failure.

PURPOSE: To determine the long-term outcome and prognostic factors after early infrainguinal graft failure (< 30 days). METHODS: Retrospective analysis of limb salvage data, patency data, and prognostic risk factors in 112 new infrainguinal bypass grafts from 1985 to 1995 that occluded within 30 days of operation. RESULT: Thirty-six femoropopliteal and 76 femorotibial/femoropedal arterial bypass ("index") procedures were performed for rest pain (50%), tissue loss (31%), or disabling claudication (19%). In 103 patients, an immediate additional revascularization ("takeback") procedure was performed at the time of early graft failure. Life table analysis of the takeback procedures for threatened limbs (n = 84) revealed limb salvage rates of 74%, 54%, 40%, and 31% at 1 month, 1 year, 3 years, and 5 years, respectively. The 1-month limb salvage rate (threatened limbs) was 12% (1 of 8) in patients who were not taken back for revascularization and 33% (4 of 12) in patients who had undergone more than one takeback procedure within 30 days. The secondary graft patency rates for the takeback procedures (n = 103) were 70%, 37%, 27%, and 23% at 1 month, 1 year, 3 years, and 5 years, respectively. Univariate and life table analysis revealed that patients who were given anticoagulation medication after the index procedure (before graft thrombosis) or patients who had undergone previous ipsilateral leg revascularization had significantly lower rates of limb salvage and graft patency (p < 0.05). The limb salvage rate was also significantly worse in patients who had single-vessel runoff compared with those who had multiple-vessel runoff (p < 0.01). Thrombectomy and revision or complete graft replacement had a better secondary patency rate than thrombectomy alone (p < 0.05). Autogenous vein grafts had better outcome than polytetrafluoroethylene-containing grafts, but statistical significance was not achieved. No significant differences in limb salvage or graft patency rates were found between femoropopliteal versus femorotibial/femoropedal bypass grafting, age, gender, previous inflow surgery, diabetes, hypertension, smoking, or cardiac, renal, or pulmonary disease. CONCLUSION: The long-term limb salvage and graft patency rates after takeback revascularization procedures for early graft failure are poor. Despite poor outcome, a single takeback procedure appears warranted in all patients. Multiple takeback procedures, however, do not appear to be justified, especially in patients who are given anticoagulation medication after the index bypass procedure, repeat leg bypass procedures, or if there is no potential for graft revision.

Aged↗
PubMed1997

Prosthetic above-knee femoropopliteal bypass grafting: results of a multicenter randomized prospective trial. Above-Knee Femoropopliteal Study Group.

PURPOSE: There are excellent arguments in favor of the preferential use of prosthetic grafts above the knee for the treatment of infrainguinal occlusive disease. This approach has been popularized on the basis of the seemingly acceptable results when using polytetrafluoroethylene (PTFE). However, in many centers, knitted Dacron polyester has been used in these patients, and there are several studies that show equivalent and, in some, superior results with Dacron when compared with PTFE. The purpose of this study was to examine these results in a definitive way. METHODS: A randomized prospective trial in eight clinical academic centers in the United States and Canada was initiated in 1991. Two hundred forty-four patients eligible for such a study, by virtue of criteria extant in each institution at the time, were centrally randomized. They underwent placement of either a knitted Dacron polyester graft impregnated with collagen or a thin-wall expanded reenforced PTFE graft to the above-knee popliteal artery, usually from the common femoral artery. They were frequently observed by protocol for as long as 5 years by a physical examination noninvasive hemodynamic study, including duplex scanning in many instances. Continuing patency was noted, as were other potential adverse outcome events. The data were analyzed by the log-rank test for cumulative patency and expressed as Kaplan-Meier curves. Data were further analyzed with a Cox proportional hazards model. RESULTS: There were no differences in graft groups in demographic or comorbid factors. The procedural mortality rate was zero, and the morbidity rate was low (6.5%). The long-term patient survival rate was excellent (77% at 3 years). At the end of these years, no statistical significance in primary or secondary patency rates was observed between the two grafts (primary patency rate, 62% +/- 14.4% for Dacron; 57% +/- 15.5% for PTFE). No unexpected adverse outcomes on limb status were noted. Patency rates in both graft groups were inferior in patients who received small grafts (5 to 6 mm vs 7 to 8 mm; hazards ratio, 4.15) and younger (<65 years) smoking patients. CONCLUSIONS: The fact that these two prosthetic grafts performed in equivalent fashion in a controlled, well-conducted prospective study is not surprising in spite of the previous work that suggested differences. If the preferential use of synthetic bypass grafts above the knee is to be used, it should be restricted to older nonsmokers with favorable anatomy. In that instance, the choice of graft material will depend on handling characteristics and cost. Above-knee prostheses should be only selectively used in younger, smoking patients, and graft size should be carefully considered in patients who undergo this operation.

Arterial Occlusive Diseases↗
PubMed1997

Blunt injury of the abdominal aorta: a review.

Injury to the abdominal aorta after blunt trauma occurs much less frequently than injury to the thoracic aorta. Although presentations vary, common themes continue to emerge with each patient. Within a 6-month period, our trauma unit diagnosed and treated two cases of blunt abdominal aortic trauma. Both patients were restrained passengers in motor vehicle crashes with resultant abdominal aortic injuries and demonstrated some of the most common associated injuries. Our two cases bring the number found in the literature to 62 and demonstrate the need for rapid recognition and treatment of this potentially lethal injury. This article is a comprehensive review of the management of abdominal aortic injury from blunt trauma.

Accidents, Traffic↗
PubMed1996

A new technique for hemodialysis access surgery: use of the pneumatic tourniquet.

The purpose of this study was to determine whether tourniquet occlusion could be safely used on the upper extremity for vascular control during hemodialysis access surgery. The hospital and outpatient records of 44 patients undergoing 105 hemodialysis access procedures were retrospectively reviewed. In 48 procedures tourniquet occlusion was used for vascular control, whereas in 57 procedures vascular clamps were used. In those procedures in which the tourniquet was used, the mean tourniquet time was 30 minutes and the mean tourniquet pressure was 242 mm Hg. The operative time was significantly less in the tourniquet group as compared to the clamp group (72.5 minutes vs. 84 minutes, respectively; p = 0.029). There was no statistically significant difference in the incidence of nerve injury, bleeding, hematoma, vascular steal, infection, or swelling between the two groups. There were no complications related specifically to the use of the tourniquet. There was no difference in primary patency in comparing the tourniquet control group with the clamp control group (p > 0.5). The use of a pneumatic tourniquet for vascular control during hemodialysis access surgery allows for a faster, technically easier operation with no increase in the complication rate and no effect on primary patency.

Ambulatory Surgical Procedures↗
PubMed1995

Fundraising, government grants and donations to nonprofit hospital charities.

Using 1982-1987 tax return data from California hospital charities, this paper investigates the relationship between fundraising expenditures, government grants and donations, during a time in which significant changes were being made in the system of hospital reimbursement. Empirical results suggest that while donations have been declining, charities have been efficient in their solicitation of donations. Results also suggest that government grants worked to reduce charitable contributions in the period before the institution of Medicare's Prospective Payment System. In more recent years, government grants have been associated with increases in donations to hospital charities.

California↗
PubMed1995

Philanthropy and hospital financing.

OBJECTIVE: This study explores the relationships among donations to not-for-profit hospitals, the returns provided by these hospitals, and fund-raising efforts. It tests a model of hospital behavior and addresses an earlier debate regarding the supply price of donations. DATA SOURCES: The main data source is the California Office of Statewide Health Planning data tapes of hospital financial disclosure reports for fiscal years 1980/1981 through 1986/1987. Complete data were available for 160 hospitals. STUDY DESIGN: Three structural equations (donations, returns, and fund-raising) are estimated as a system using a fixed-effects, pooled cross-section, time-series least squares regression. PRINCIPAL FINDINGS: Estimation results reveal the expected positive relation between donations and returns. The reverse relation between returns and donations is insignificant. The estimated effect of fund-raising on donations is insignificantly different from zero, and the effect of donations on fund-raising is negative. Fund-raising and returns are negatively associated with one another. CONCLUSION: The empirical results presented here suggest a positive donations-returns relations and are consistent with a positive supply price for donations. Hospitals appear to view a trade-off between providing returns and soliciting donations, but donors do not respond equally to these two activities. Attempts to increase free cash flow through expansion of community returns or fund-raising activity, at least in the short run, are not likely to be highly successful financing strategies for many hospitals.

California↗
PubMed1994

Angioscopic evaluation of valvular disruption during in situ saphenous vein bypass.

Several valvulotomes are currently available to achieve valvular disruption; however, studies comparing the efficacy of these endoluminal instruments are lacking. This prospective study evaluates the efficacy and safety of the three most commonly employed valve cutters: the Hall, LeMaitre, and Mills valvulotomes. A total of 30 in situ greater saphenous vein bypass grafts were included in this investigation. Valvular disruption was attempted with either the LeMaitre (11 cases), Hall (12 cases), or Mills (7 cases) valvulotomes. Subsequently, angioscopy was employed to assess the completeness of valvulotomy and to identify vein wall injury. Incomplete disruption of one or more valve complexes was identified in 2 of 12 (17%) grafts in the Hall group, 10 of 11 (91%) grafts in the LeMaitre group, and 0 of 7 grafts in the Mills group (p < 0.01). Intact valve cusps were noted in 2 of 36 (5.5%) valves, 31 of 42 (74%) valves, and 0 of 38 valves after valvulotomy with the Hall, LeMaitre, and Mills instruments, respectively (p < 0.01). A total of three valvulotome-related injuries occurred; two injuries were noted in conjunction with the Hall instrument, one was associated with the Mills valvulotome, and no injuries were detected after use of the LeMaitre instrument (p = 0.33). These data demonstrated a significantly increased incidence of retained valve cusps when the LeMaitre valvulotome was used. No significant difference in the rate of vein wall injury was noted in the three groups. Thus this study suggests that the LeMaitre instrument is not as effective as either the Hall or Mills valvulotomes for achieving valvular disruption.

Adult↗
PubMed1994

Long-term follow-up for recurrent stenosis: a prospective randomized study of expanded polytetrafluoroethylene patch angioplasty versus primary closure after carotid endarterectomy.

PURPOSE: To determine the effect of primary closure (PC) versus expanded polytetrafluoroethylene patch graft angioplasty (PGA) on the incidence of recurrent stenosis (> 50% lumen diameter narrowing) after carotid endarterectomy (CEA), 87 patients undergoing 100 consecutive CEA were prospectively randomized into two groups. METHODS: Forty-four patients underwent 51 PC, and 43 patients underwent 49 PGA. All patients were evaluated after operation by duplex scanning at 1.5, 12, 24, and 36 months. There were no significant differences in the demographic characteristics or operative indications for CEA between the two patient groups. Complete follow-up was achieved in 86% (75/87) of the patients during the 36-month surveillance period. RESULTS: The perioperative permanent neurologic morbidity in the PC and PGA groups was noted to be 4% and 2%, respectively (PC = 2/51 vs PGA = 1/49, p = 0.58). Three additional reversible cerebral ischemic events occurred in the postoperative period (PC = 2/51 vs PGA = 1/49, p = 0.58). Other morbidity included immediate postoperative hemorrhage requiring reexploration (1/51) in the PC group and an infected expanded polytetrafluoroethylene patch requiring removal and replacement with autogenous vein (1/49). Long-term follow-up detected a single patient with significant bilateral restenoses of his primarily closed carotid arteries. None of the patients in the PGA group had restenoses (PC = 2/51 vs 0/49, p = 0.50). In addition, no postoperative dilation of the common or internal carotid arteries or perioperative death was observed. CONCLUSIONS: In patients undergoing CEA, these data demonstrate no significant difference in the perioperative morbidity or mortality between PC and PGA. Use of the patch did not engender patients to patch rupture or aneurysmal degeneration as previously described with vein patch angioplasty procedures. This series supports effective use of either technique to achieve minimal rates of restenosis.

Adult↗
PubMed1994

Chylomicrons or their remnants penetrate rabbit thoracic aorta as efficiently as do smaller macromolecules, including low-density lipoprotein, high-density lipoprotein, and albumin.

BACKGROUND: The aortic accumulation of chylomicrons, low-density lipoprotein (LDL), high-density lipoprotein (HDL) and albumin were compared in normal New Zealand White rabbits. METHODS: Lipoproteins and albumin were labelled with radioiodinated tyramine cellobiose (TC) to avoid potential oxidative modification of lipoproteins and as a marker of intracellular degradation. In preliminary experiments it was established that TC labelling did not alter the kinetic properties of lipoproteins in vivo. Importantly, radiolabelled apolipoproteins did not transfer significantly between plasma lipoproteins. Therefore, aortic radioactivity following infusion of TC-radiolabelled lipoproteins was considered to be indicative of lipoprotein accumulation. RESULTS: In conscious rabbits, net aortic accumulation of chylomicrons or their remnants was similar to those of LDL, HDL and albumin up to 2 h after infusion, despite rapid clearance from plasma. When accumulation was calculated on the basis of mean arterial exposure to allow for the differences in plasma clearance, the accumulation of aortic chylomicrons/remnants was substantially greater than that of LDL, HDL or albumin. Qualitatively similar results were obtained in rabbits that were functionally eviscerated to slow clearance of chylomicron remnants. Chylomicrons/remnants did not appear to efflux from aortic tissue as rapidly as did LDL or other plasma lipoproteins. Autoradiographic analysis showed that the primary site of lipoprotein accumulation was within medial smooth muscle cells. CONCLUSION: Our data demonstrate that chylomicrons/remnants accumulate in arterial blood vessels more rapidly than does LDL, suggesting that dietary lipoproteins may be directly involved in the pathogenesis of atherosclerosis.

Albumins↗
PubMed1994

What do we want and what do we get from not-for-profit hospitals?

The tax exemption for not-for-profit hospitals has been subject to many recent challenges, in part related to concerns over whether these hospitals provide sufficient levels of community benefits to merit tax exemption. Computing the value of community benefits for California hospitals as the sum of uncompensated care, education and research, net income, money-losing services, and price discounts from for-profit hospitals reveals that 20 to 80 percent of hospitals would have met various recommended community benefits standards. There is a clear need for hospitals and their communities to establish dialogues on what levels of community benefits are appropriate.

Accounting↗
PubMed1994

Vein harvest ischemia: a peripheral vascular complication of coronary artery bypass grafting.

Lower-extremity ischemia can lead to impaired healing of saphenous vein excision sites in patients with significant peripheral vascular disease (PVD). Five patients who required infrainguinal revascularization for wound necrosis of the harvest site after coronary artery bypass grafting are described. The male/female ratio was 2:3 with a mean age of 67 (range 45-87) years. The most commonly associated problems were insulin-dependent diabetes mellitus (80%) and congestive heart failure (60%). The saphenous vein was harvested from the thigh and leg in three patients and exclusively from the leg in the others. Manifestations of ischemia ranged from persistent ulceration to complete wound disruption threatening limb loss. Impaired healing was isolated to infragenicular wounds in all patients. Pedal pulses were not detected in any of the affected extremities. Determination of the ankle/brachial pressure indices (ABI) revealed values of < 0.5 in three affected limbs. Non-compressible vessels resulted in falsely raised ABI of > 1.0 in the remaining two limbs; however, Doppler waveform analysis in these patients demonstrated significant PVD. Aggressive wound care and antibiotic therapy were continued for mean of 9 weeks before operative intervention. Infrainguinal reconstruction included femoropopliteal (two), femorotibial (two) and popliteal-tibial bypass (one). Autologous arm and saphenous veins in addition to expanded polytetrafluoroethylene grafts were used effectively. Limb salvage and wound healing were achieved in 100% of the patients without untoward sequelae. It is concluded that unrecognized PVD in patients undergoing coronary artery bypass grafting can lead to significant morbidity. Patients at risk may be identified with a combination of history, physical examination and non-invasive testing.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1994

Intraoperative iliac artery stents: combination with infra-inguinal revascularization procedures.

Iliac artery percutaneous transluminal angioplasty (PTA) can effectively provide in-flow for subsequent distal vascular reconstruction. Iliac artery stents may improve the initial hemodynamics and long term patency of PTA, and thus may be well-suited for combined proximal PTA with distal bypass procedures. This report reviews our preliminary experience with iliac artery stenting in combination with infra-inguinal vascular reconstruction. Thirteen iliac artery stent procedures combined with simultaneous distal revascularization were performed in 11 patients. Ten procedures were performed for limb salvage, two for disabling claudication, and one before planned orthopedic surgery. Distal revascularization procedures included seven femoropopliteal, four femorotibial bypasses, one common femoral endarterectomy, and one thrombectomy of a femoropopliteal bypass. Stent placement was technically successful in all patients. Mean pre-operative ankle-brachial index (ABI) was 0.41 (+/- 0.28), which improved to 0.91 (+/- 0.18) post-operatively (P < 0.0001). Mean systolic iliac artery gradients across the lesions improved from 27.1 (+/- 9.8) mm Hg to 2.7 (+/- 3.4) mm Hg after stent placement (P < 0.0001). Mean follow-up is 5.8 months (range 1-12 months). Two femoropopliteal bypass grafts occluded in the follow-up period. One occlusion was caused by a mid-vein graft stenosis that was repaired with subsequent graft patency. The other graft occlusion occurred in a patient with rest pain who did not require a second bypass procedure, as the ABI increased from 0.3 to 0.7 following stent placement with resolution of symptoms.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1994

Coexistent abdominal aortic aneurysm and renal carcinoma: management options.

Renal carcinoma (RCA) presenting in association with abdominal aortic aneurysm (AAA) is extremely rare, with only sporadic case reports previously described. The management of six cases of AAA and concomitant RCA presenting to a single institution from March, 1991 through December, 1993 was reviewed and management options considered. AAAs ranged in size from 4.5-7.0 cm (mean, 5.6 cm). Three left renal carcinomas were resected via a retroperitoneal approach simultaneous to repair of the AAA. One right renal carcinoma was resected in combination with repair of an AAA through a transperitoneal approach. The fifth case was managed by left nephrectomy, followed by interval aneurysmectomy, and the sixth case was managed by nonsurgical methods because of the presence of widely metastatic disease. Renal malignancies included five renal cell carcinomas and one transitional cell carcinoma. Three patients remain free of disease 8-11 months postoperatively, and one patient had metastatic disease detected 19 months postoperatively. Two deaths have occurred; one due to a massive CVA 1 month following a combined aneurysmectomy and left nephrectomy, and a second due to unknown etiology in the patient managed non-surgically. No peripheral vascular or aortic graft related complications have occurred. The treatment of AAA and RCA should be governed by the size of the AAA, the location of the cancer, and the extent of malignant disease. Simultaneous resection is safe and effective in patients with coexistent AAA and renal cancer. Left sided tumors should be resected via a retroperitoneal approach that also provides excellent exposure for simultaneous AAA resection.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗