Showing papers by "Gilbert R. Upchurch published in 2004"
TL;DR: The number of hepatic resections performed in the US has increased significantly and short-term outcomes have also improved over the same time period, with more improvement seen at higher volume centers than in lower volume centers.
Abstract: Background Hepatic resection is increasingly performed for primary and metastatic tumors. Reports from tertiary care centers show improved outcomes over time with lower operative mortality rates. The objective of this investigation was to characterize trends in the use and outcomes of hepatic resection in the US during a recent 13-year period. Study design Adult patients with a procedures code for hepatic resection in the Nationwide Inpatient Sample (NIS) from 1988 to 2000 were included. The Nationwide Inpatient Sample is a 20% representative sample of all discharges in the US. Outcomes variables included in-hospital mortality and length of stay. High volume hospitals performed 10 or more (>50th percentile) procedures per year. Results During the 13-year period, 16,582 patients underwent hepatic resection. The number of procedures performed increased nearly twofold, from 820 per year in 1988 to 1,420 per year in 2000. Similar changes in use were seen for each indication for operation. The overall mortality rate declined from 10.4% (1988 to 1989) to 5.3% (1999 to 2000) during the study period (p Conclusions The number of hepatic resections performed in the US has increased significantly. Short-term outcomes have also improved over the same time period, with more improvement seen at higher volume centers than in lower volume centers.
207 citations
TL;DR: Teaching hospitals have lower operative mortality rates for complex surgical procedures, however, the lower mortality rates at teaching hospitals can be explained by higher procedural volume.
Abstract: Hypothesis Complex operations performed in teaching hospitals have similar outcomes as those performed in nonteaching hospitals. Design Observational cohort study with clinical patient data obtained from the Nationwide Inpatient Sample. The Nationwide Inpatient Sample data were linked to the American Hospital Association hospital survey data for 1997 to determine hospital characteristics. Hospitals were considered high volume if they performed more than the median (50th percentile) number of procedures per year. Setting Nationally representative sample of hospitals during 1996 and 1997. Patients Individuals undergoing esophageal resection (n = 1247), hepatic resection (n = 2073), or pancreatic resection (n = 3337) in Nationwide Inpatient Sample hospitals during 1996 and 1997 were included. Main Outcomes Measures Unadjusted and adjusted in-hospital mortality and prolonged length of stay (>75th percentile). Results None of the procedures had higher operative mortality rates at teaching hospitals. In unadjusted analyses, pancreatic resection (4.0% vs 8.8%;P Conclusions Teaching hospitals have lower operative mortality rates for complex surgical procedures. However, the lower mortality rates at teaching hospitals can be explained by higher procedural volume.
203 citations
TL;DR: Patients undergoing infrainguinal bypass are undertreated with respect to cardioprotective medications, and statin drug use is associated with improved graft patency and limb salvage.
144 citations
TL;DR: Normal DVT resolution involves CXCR2-mediated neovascularization, collagen turnover, and fibrinolysis, and it is probably primarily monocyte-dependent.
Abstract: Objective— To determine the role of CXCR2, the receptor for cysteine-X-cysteine (CXC) chemokines, and its primary effector cell, the neutrophil (PMN), on deep venous thrombosis (DVT) resolution. Methods and Results— DVT in BALB/c, anti-CXCR2 antibody-treated, and BALB/c CXCR2−/− mice were created by infrarenal inferior vena cava (IVC) ligation and the thrombus harvested at various time points over 21 days. The CXCR2−/− mice had significantly larger thrombi at early time points (days 2 to 8), and significantly decreased intrathrombus PMNs, monocytes, and neovascularization as compared with controls. Thrombus KC/CXCL1 was significantly higher at 2 days in CXCR2−/− thrombi as measured by enzyme-linked immunosorbent assay. Fibrin content was significantly higher, with less uPA gene expression at 4 days in CXCR2−/− thrombi. Late fibrotic maturation of the thrombus was delayed in the CXCR2−/− mice, with significantly decreased 8 day MMP-2 activity, whereas MMP-9 activity was elevated as compared with controls. ...
136 citations
TL;DR: Iliac artery angioplasty and stenting has rapidly gained a large market share in the treatment of aorto-iliac occlusive disease and accepted clinical outcomes have likely lowered the threshold for treatment and contributed to the rapid diffusion of this technology.
79 citations
TL;DR: The hypothesis that adrenalectomy has become more common over time and that benign diseases have been increasingly represented among procedural indications is tested and it is suggested that indications for Adrenalectomy may have changed somewhat over that period.
Abstract: Minimally invasive approaches have dramatically reduced morbidity associated with adrenalectomy. There has been concern that an increased frequency of adrenal imaging along with the advantages of less morbidity could influence the indications for adrenalectomy. We tested the hypothesis that adrenalectomy has become more common over time and that benign diseases have been increasingly represented among procedural indications. The Nationwide Inpatient Sample (NIS) database was utilized to determine the incidence of adrenalectomy and the associated surgical indications in the United States between 1988 and 2000. All discharged patients were identified whose primary ICD-9-CM procedure code was for adrenalectomy, regardless of the specific surgical approach (laparoscopic adrenalectomy was not reliably coded). This subset was then queried for associated ICD-9-CM diagnostic codes. Linear regression and t-tests were utilized to determine the significance of trends. The total number of adrenalectomies increased significantly, from 12.9 per 100,000 discharges in 1988 to 18.5 per 100,000 discharges in 2000 (p = 0.000003). The total number of adrenalectomies with a primary ICD-9-CM code for malignant adrenal neoplasm did not increase significantly: from 1.2 per 100,000 discharges in 1988 to 1.6 per 100,000 discharges in 2000 (p = 0.47). The total number of adrenalectomies with a primary ICD-9-CM diagnostic code for benign adrenal neoplasm increased significantly, from 2.8 per 100,000 discharges in 1988 to 4.8 per 100,000 discharges in 2000 (p = 0.00002). The average percentage of adrenalectomies performed for malignant neoplasm was significantly higher during the period 1988–1993 when compared to 1994–2000 (11% vs. 9%; p = 0.002). The average percentage of adrenalectomies performed for benign neoplasm was significantly lower during 1988–1993 when compared to 1994–2000 (25% vs. 28%; p = 0.015). Adrenalectomy is being performed with increasing frequency. This is associated with an increase in the proportion of adrenalectomies performed for benign neoplasms. Assuming no significant change in disease prevalence during the study period, these data suggest that indications for adrenalectomy may have changed somewhat over that period.
74 citations
TL;DR: Older patient age is independently associated with an increased risk of major postoperative complications after AAA repair, and quality improvement efforts must focus on minimizing complication rates in elderly patients undergoing common vascular surgical procedures including AAA repair.
53 citations
TL;DR: Stoke after noncarotid peripheral vascular surgery is uncommon, but results in markedly increased mortality and length of stay, and Stroke risk is most strongly associated with previous stroke history and greater degree of illness.
52 citations
TL;DR: Findings support the tenet that gender-related differences in MMP-9 may contribute to AAA formation.
Abstract: Background A predilection exists for men to develop abdominal aortic aneurysms (AAAs), but the reasons for this gender predisposition are not known. Matrix metalloproteinase-9 (MMP-9) has been implicated in both human and experimental AAAs. This investigation tested the hypothesis that male and female gender differences exist in the production of MMP-9 by rat aortic smooth muscle cells (RASMCs). Study design In the first set of experiments, cultured male and female RASMCs were stimulated with interleukin-1 beta (IL-1β) at 2 ng/mL. Messenger RNA was extracted from the RASMCs and gene expression of MMP-9 and tissue inhibitor of metalloproteinase-1 (TIMP-1), an MMP-9 inhibitor, was measured by quantitative real-time polymerase chain reaction. Cell culture media were collected for measurement of MMP-9 protein levels and MMP-9 activity by Western blotting and gelatin zymography, respectively. In the second set of experiments, male RASMCs were treated with 17-β-estradiol (10 −10 to 10 −6 mol/L) and MMP-9 activity was measured. In the third set of experiments, male rats were pretreated with estradiol, and MMP-9 activity was measured in the media from explanted aortas. Results MMP-9 gene expression was 10-fold higher in male versus female RASMCs (p=0.003). MMP-9 protein levels (p=0.005) and gelatinolytic activities (p=0.01) were also greater in male than female RASMCs. TIMP-1 expression was fourfold higher in male versus female RASMCs (p Conclusions MMP-9 and TIMP-1 are greater in male than in female RASMCs. These findings support the tenet that gender-related differences in MMP-9 may contribute to AAA formation.
50 citations
TL;DR: Eighteen patients (14 men, 4 women), ages 24 to 77 years, with a common celiacomesenteric trunk, were treated between 1965 and 2004 at the University of Michigan, with four patients having CMT aneurysmal or occlusive disease that led to operative treatment.
49 citations
TL;DR: This study evaluated promoting DVT neovascularization with angiogenic chemokines, and, while successful by experimental measures, this did not translate into smaller DVT.
TL;DR: MMP-9 expression and activity is increased in cytokine stimulated RA-SMCs after iNOS inhibition, coincident with activation of the nuclear factor-kappaB and activator protein-1 pathways.
TL;DR: A significant change in the management of patients with renovascular hypertension has occurred, with a shift towards less invasive catheter-based interventions.
TL;DR: The rodent aortic aneurysm model exhibits upregulation of MT1-MMP expression and protein with subsequent increased conversion of MMP-2 from the latent to the cleaved form.
TL;DR: Intact AAA repair by conventional means has become increasingly safe, with decreased operative mortality and shorter hospital stays, suggesting possible reductions in risk factors contributing to rupture, coupled with more timely intact AAA repairs.
Abstract: Abdominal aortic aneurysm (AAA) repair is a complex procedure about which little information exists regarding trends in surgical practice in the United States. This study was undertaken to define benchmark data regarding performance and outcomes of conventional AAA repair that might be used in comparisons with endovascular AAA repair data. Patients undergoing repair of intact (n = 87,728) or ruptured (n = 16,295) AAAs in the Nationwide Inpatient Sample (NIS) for 1988 to 2000 were studied. The NIS represents a 20% stratified random sample of all discharges from US hospitals. Unadjusted and case mix-adjusted analyses of in-hospital mortality and length of stay were performed. The overall frequency of intact AAA repair remained relatively stable during the study period, ranging from 18.1 to 16.3 operations/100,000 adults between 1988 and 2000, respectively. The operative mortality rate for intact AAA repair decreased significantly (p < .001) from 6.5% in 1988 to 4.3% in 2000. Length of stay following intact AAA repair also declined significantly (p < .001) from a median of 11 days in 1988 (interquartile range [IQR] 9-15 days) to 7 days in 2000 (IQR 5-10 days). The incidence of ruptured AAA repair decreased significantly (p < .001) from 4.2 to 2.6 operations/100,000 adults between 1988 and 2000, respectively. Mortality for ruptured AAA repair, averaging 45.6%, did not decrease significantly during the study period. Intact AAA repair by conventional means has become increasingly safe, with decreased operative mortality and shorter hospital stays. Ruptured AAA repair by conventional means has not become safer but has decreased in incidence, suggesting possible reductions in risk factors contributing to rupture, coupled with more timely intact AAA repairs.
TL;DR: Patients undergoing CEA who are hemodynamically stable in the PACU appear to be reasonable candidates for same-day discharge and warrant further prospective study.
Abstract: This study was undertaken to identify preoperative and intraoperative factors that correlate with the need for postoperative vasoactive medication (VM) use. Clinical data from 100 carotid endarterectomies (CEAs) performed in 93 patients were reviewed. Baseline comorbidities, medications, perioperative physiologic data, and operative technique were evaluated for their association with the need for postoperative VM use. Statistical analysis included univariate and multivariate logistic regression with odds ratios (ORs) and 95% confidence intervals (CIs) reported. Hemodynamic instability affected 43 patients, of whom 32 had VM started in the postanesthesia care unit (PACU). No patient who was hemodynamically stable in the PACU later required VM. The only preoperative factor associated with a need for postoperative VM was a prior stroke (OR 4.5; 95% CI 1.2-16.2; p = .02). Intraoperative factors associated with the need for postoperative VM included use of a shunt (OR 5.1; 95% CI 1.2-22.2; p = .03) and a peak intraoperative systolic blood pressure greater than 200 mm Hg (OR 5.1; 95% CI 1.2-22.2; p = .03). The number and type of preoperative blood pressure medications, preoperative hypertension, comorbidities, symptomatic presentation, and intraoperative use of VM did not correlate with postoperative VM use. There were two strokes and no deaths. Patients undergoing CEA who are hemodynamically stable in the PACU appear to be reasonable candidates for same-day discharge and warrant further prospective study.
TL;DR: It is concluded that a uPA deficiency has a protective effect against Ang II-induced AAA development, that uPA is not required for normal vascular development and maintenance, and that preexisting hyperlipidemia and atherosclerosis are not essential for Ang II -induced AAA formation.
Abstract: In a previous study in apolipoprotein E-deficient mice treated with angiotensin II (Ang II), the authors demonstrated that urokinasetype plasminogen activator (uPA) is highly expressed in the aneurysmal segment of the abdominal aorta. The authors conducted the present study to determine if uPA is essential for the formation of abdominal aortic aneurysm (AAA) in this same mouse model. Male mice were implanted for 1 month with a subcutaneous osmotic minipump that delivered 1.44 mg/kg per day of Ang II. AAA was induced in 90% of apoE deficient mice, but only 22% of the mice deficient in both apoE and uPA developed AAA. In 18 strainmatched wild type control mice, Ang 11 induced AAA in 39%. The author's concluded that a uPA deficiency has a protective effect against Ang II-induced AAA development, that uPA is not required for normal vascular development and maintenance, and that preexisting hyperlipidemia and atherosclerosis are not essential for Ang II-induced AAA formation.
TL;DR: The Nationwide Inpatient Sample (NIS) contains data for hospital discharges in the United States that report a consistent mortality rate despite improved therapy, and regional diagnostic, treatment, and economic differences exist.
Abstract: Venous thromboembolism (VTE) is a costly complication of hospitalization. The sequelae make it a concern for public health planners. The Nationwide Inpatient Sample (NIS) contains data for hospital discharges in the United States. These data were reviewed to determine their suitability for health policy planning. International Classification of Diseases, Ninth Revision, Clinical Modification codes for VTE were applied to the NIS data. The sample was queried for demographic information, mortality, length of hospital stay, diagnosis, and treatment. The rates were standardized for geographic region and disease acuity. Statistical analysis included descriptive reporting of means and event rates; analysis of variance and logistic regression were used for regional effects and modeling of mortality. Between 1993 and 2000, 636,814 discharges involved VTE (1.2%). This rate was consistent over time and within regions. Regional differences existed in the acceptance of new technology and hospital charges. Mortality varied from 6.3% (Midwest) to 7.9% (Northeast) and was associated with admission type, comorbidities, pulmonary embolism, and discharge from the Northeast region. White race, chronic venous insufficiency, and female gender were protective variables. The NIS data report a consistent mortality rate despite improved therapy. Regional diagnostic, treatment, and economic differences exist. The data are useful for the purposes of public health care planning and stimulating clinical trial questions.
TL;DR: The patient has been treated conservatively, and at 4-year follow-up, she remains asymptomatic, and the carotid artery aneurysms are unchanged in size.
Abstract: A 60-year-old female was found on a physical examination to have bilateral palpable pulsatile neck masses. She denied local pain, cranial nerve compressive symptoms, or symptoms of cerebral ischemia. Duplex ultrasonography demonstrated bilateral 1.5 x 2.2 cm external carotid artery aneurysms. Isolated bilateral external carotid artery aneurysms were confirmed by computed tomography and angiography. The patient has been treated conservatively, and at 4-year follow-up, she remains asymptomatic, and the carotid artery aneurysms are unchanged in size.
TL;DR: Elastase perfused aortic aneurysm formation is associated with early increases in MnSOD expression, which primarily occurs in the mitochondria, and strategies aimed at inhibiting oxidative stress during aneurYSm formation should focus on this specific SOD isoform.