Gender differences in abdominal aortic aneurysm prevalence, treatment, and outcome

AbstractPurpose: The purpose of this study was to investigate gender differences in the management of and outcome of surgery for abdominal aortic aneurysms (AAA).Methods: Hospital discharge data from all acute care hospitals in Michigan, as compiled in the Michigan Inpatient Data Base, were retrospectively analyzed to assess sex differences in regard to AAA prevalence, treatment, and surgical outcome from 1980 to 1990. This population database included 11,512 women and 29,846 men 50 years of age and older with diagnoses of intact or ruptured AAA.Results: Hospitalizations for intact or ruptured AAA were approximately five times more common among men compared with women. After controlling for age and year of surgery, men were 1.8 times as likely as women to have an intact AAA treated surgically and 1.4 times as likely to have a ruptured AAA treated surgically (95% confidence intervals, 1.7 to 1.9 and 1.2 to 1.7, respectively). Women who had operations for intact AAA had a 1.4 times greater risk of dying compared with men, and women who had operations for ruptured AAA had a 1.45 times greater risk of dying, after controlling for other predictors of death (95% confidence intervals, 1.14 to 1.73 and 1.10 to 1.90, respectively).Conclusions: In a population-based statewide experience, women who had intact or ruptured AAA were less likely than men to undergo aortic reconstruction and, when they did, were less likely than men to survive to discharge. (J Vasc Surg 1997;25:561-8.

NIBRS Data Available for Secondary Analysis

The NIBRS data program currently being implemented by the FBI and local lawenforcement agencies has by now produced sufficient data for archiving anddistribution. Although not representative of crime in the United States, existing NIBRS data can be used to investigate the nature of crimesknown to the police compared to the traditional UCR data. The Bureau ofJustice Statistics has requested the National Archive of Criminal JusticeData to store and make NIBRS data available to interested users. The datafrom 1996 will shortly be available from the NACJD web site. The 1996 datacontain almost 6.5 million records and the FBI's full file includes about 361 Mbytes of data. The data have been disaggregated from the FBI's complex single file into 11 segment levels or record types. This makes theindividual record types easier and faster to analyze than using the fullfile, which more closely resembles a relational database than a hierarchicalfile. However, splitting apart the record types requires that specialprocedures be used to merge files of different record types, which would benecessary if a user were interested in analyzing variables appearing in morethan one record type (e.g., comparing offender and victim ages). These procedures are described, and a test comparing the time to run a simple frequencycount using the full file against the merged files shows that using themerged files is considerably more efficient. Also discussed are some futuredevelopments to facilitate the analysis of NIBRS data.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45110/1/10940_2004_Article_220510.pd

Ischemia with intermittent reperfusion reduces functional and morphologic damage following renal ischemia in the rat

Attempts to minimize ischemic injury by interrupting a given ischemic period might be compromised if repeated bouts of reperfusion injury occurred. To determine whether intermittent ischemia improved or worsened functional and morphologic outcome of renal ischemia, halothaneanesthetized rats underwent a right nephrectomy and placement of a snare about the left renal vascular pedicle at 37° C. Eleven animals underwent 45 minutes of continuous renal ischemia (C-ISC), whereas 10 animals received 45 minutes of vessel occlusion interrupted (I-ISC) at 15 and 30 minutes by snare release and 5 minutes of reperfusion. A group of three sham rats underwent the above procedure but did not have the snare tightened. Blood samples were drawn preoperatively and 24, 48, and 72 hours postoperatively for creatinine analysis. At 72 hours the animals were sacrificed and their kidneys morphologically evaluated. The C-ISC group had a significantly higher mean postoperative plasma creatinine ( p <0.01) as well as significantly higher plasma creatinine levels at 24 ( p <0.005) and 48 hours ( p <0.05) than did the I-ISC group. The C-ISC group also demonstrated significantly greater histologic damage than the I-ISC group ( p <0.002) when assessed by a pathologist blinded to the intervention. Sham rats did not demonstrate functional or morphologic damage. These data demonstrate a significantly improved outcome when 45 minutes of renal ischemia is interrupted by periods of reperfusion. We are led to conclude that in this setting reperfusion injury did not overwhelm the salutary effects of interrupting the 45-minute ischemic event.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/41372/1/10016_2005_Article_BF02001009.pd

Hyperglycemia exacerbates and insulin fails to protect in acute renal ischemia in the rat

Hyperglycemia worsens ischemic injury in several ischemic models. To determine whether renal lactate accumulation was associated with hyperglycemia-exacerbated postischemic renal dysfunction and mortality, halothane-anesthetized rats underwent right nephrectomy and 45 min of left renal artery and vein occlusion. Prior to ischemia, rats received saline (n = 22), glucose (2 g/kg, n = 22), or insulin (4 U/kg, n = 18). Sham-operated glucose-treated rats (2 g/kg, n = 4) underwent right nephrectomy and no vascular occlusion. As anticipated, glucose pretreatment elevated plasma glucose, while insulin pretreatment lowered plasma glucose; both were significantly different from values in saline controls. Creatinine was unchanged in sham-operated rats but was significantly higher in glucose-treated rats at 24 and 48 hr postischemia compared to saline controls. No statistical differences in creatinine were found when comparing saline controls to insulin-treated rats. Eighteen percent of glucose-treated rats survived to 72 hr postocclusion, while 45% of insulin-treated rats, 73% of saline control rats, and 100% of sham-operated rats survived this period. In a separate but identical treatment protocol, renal tissue was serially sampled and lactate content was determined in rats pretreated with saline (n = 7), glucose (n = 6) or insulin (n = 6) or sham-operated (n = 2) and receiving identical operation. Tissue lactate concentration did not change during serial sampling in the sham group. During ischemia, lactate was significantly higher in glucose-treated rats and significantly lower in insulin-treated rats as compared to saline controls. The adverse effects of exogenous glucose and attendant hyperglycemia on renal function during normothermic renal ischemia are demonstrated. Increased anaerobic metabolism of glucose with marked lactate accumulation may increase the severity of injury. However, a direct link between tissue lactate and ischemic damage is not fully supported since insulin reduced renal lactate but failed to lessen morbidity and mortality.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/27924/1/0000348.pd

Infusion of five percent dextrose increases mortality and morbidity following six minutes of cardiac arrest in resuscitated dogs

The aim of this study was to assess the effect of dextrose administration during and following cardiac resuscitation on mortality and morbidity. Thirty-one dogs anesthetized with halothane were subjected to six minutes of ventricular fibrillation and were resuscitated with open chest cardiac message. All dogs were successfully resuscitated. Thirteen received no dextrose infusion and were fully ambulatory, eating and drinking at 24 hours. Ten of the 18 dogs receiving an infusion of 5% dextrose died before 24 hours and the eight that survived were profoundly impaired. Significantly greater neurologic deficits were recorded for dogs with higher blood glucose concentrations. We conclude that the inclusion of dextrose in fluids used in resuscitation increases mortality and morbidity.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/26775/1/0000328.pd

Gadolinium-enhanced magnetic resonance angiography of abdominal aortic aneurysms

AbstractPurpose: The objective of this study was to assess the usefulness of gadolinum-enhanced magnetic resonance angiography (MRA) for defining anatomic features relevant to performing aortic surgery for aneurysmal disease.Methods: Anatomic data defined by MRA, including abdominal aortic aneurysm (AAA) size and character, as well as the status of the celiac, mesenteric, renal, and iliac arteries, were correlated with angiography, ultrasonography, computed tomography, or operative data in 43 patients. Five MRA sequences were obtained in an hour-long examination optimized for aortoiliac, splanchnic, and renal artery imaging at 1.5 T in a body coil. Four of the sequences were performed during or after infusion of gadolinium to improve image quality.Results: MRA correctly defined the maximum aneurysm diameter, as well as its proximal and distal extent in all patients. MRA detected 33 of 35 significant stenoses among 153 splanchnic, renal, or iliac branches examined (sensitivity = 94% and specificity = 98%). MRA did not resolve the degree of aortic branch stenotic disease sufficiently to precisely grade its severity. MRA did not reliably define the status of the inferior mesenteric artery, lumbar arteries or internal iliac arteries. One ruptured AAA and one inflammatory AAA were correctly diagnosed by MRA. No patient had a contrast reaction or contrast-induced renal toxicity related to administration of gadolinium.Conclusion: Gadolinium-enhanced MRA of AAA provides appropriate, essential anatomic information for aortic reconstructive surgery in a 1-hour examination devoid of contrast-related renal toxicity or catheterization-related complications attending conventional arteriography. (J VASC SURG 1995;21:656-69.

A novel protamine variant reversal of heparin anticoagulation in human blood in vitro

AbstractPurpose: Protamine reversal of heparin anticoagulation during cardiovascular surgery may cause severe hypotension and pulmonary hypertension. A novel protamine variant, [+18RGD], has been developed that effectively reverses heparin anticoagulation without toxicity in canine experiments. Heretofore, human studies have not been undertaken. This investigation hypothesized that [+18RGD] would effectively reverse heparin anticoagulation of human blood in vitro. Methods: Fifty patients who underwent anticoagulation therapy during vascular surgery had blood sampled at baseline and 30 minutes after receiving heparin (150 IU/kg). Activated clotting times were used to define specific quantities of [+18RGD] or protamine necessary to completely reverse heparin anticoagulation in the blood sample of each patient. These defined amounts of [+18RGD] or protamine were then administered to the heparinized blood samples, and percent reversals of activated partial thromboplastin time, thrombin clotting time, and antifactor Xa/IIa levels were determined. In addition, platelet aggregation assays, as well as platelet and white blood cell counts were performed. Results: [+18RGD] and protamine were equivalent in reversing heparin as assessed by thrombin clotting time, antifactor Xa, antifactor IIa levels, and white blood cell changes. [+18RGD], when compared with protamine, was superior in this regard, as assessed by activated partial thromboplastin time (94.5 ± 1.0 vs 86.5 ± 1.3%δ, respectively; p < 0.001) and platelet declines (–3.9 ± 2.9 vs –12.8 ± 3.4 per mm3, respectively; p = 0.048). Platelet aggregation was also decreased for [+18RGD] compared with protamine (23.6 ± 1.5 vs 28.5 ± 1.9%, respectively; p = 0.048). Conclusions: [+18RGD] was as effective as protamine for in vitro reversal of heparin anticoagulation by most coagulation assays, was statistically more effective at reversal than protamine by aPTT assay, and was associated with lesser platelet reductions than protamine. [+18RGD], if less toxic than protamine in human beings, would allow for effective clinical reversal of heparin anticoagulation. (J Vasc Surg 1997;26:1043-8.