William C. Pevec

Venous Thrombosis Related to Peripherally Inserted Central Catheters

PURPOSE To determine factors that may lead to venous thrombosis in patients with peripherally inserted central catheters (PICC). MATERIALS AND METHODS The medical records of 678 patients with 813 PICCs during 1997 were cross-referenced with all patients receiving venous duplex examinations (1,631) during the same time period. Multiple factors were examined in the patients with catheter-related thrombosis, including diagnosis, solution infused, catheter tip position, vein accessed, and catheter diameter. RESULTS Nurses placed 269 PICCs with 12 venous thromboses, for a rate of 4.5%. Radiologists placed 544 PICCs with 20 venous thromboses, for a rate of 3.7%. There was no significant difference in these rates. The overall thrombosis rate was 3.9%. After multivariate analysis, only catheter diameter remained significant. There were no thromboses in catheters 3 F or smaller. The thrombosis rate was 1% for 4-F catheters, 6.6% for 5-F catheters, and 9.8% for 6-F catheters. CONCLUSIONS Thrombosis rate associated with PICCs was low (3.9%). The smallest acceptable catheter diameter should be used to decrease the incidence of venous thrombosis.

A prospective, randomized trial limiting perioperative red blood cell transfusions in vascular patients

BACKGROUND Patients undergoing major arterial reconstruction have traditionally been transfused with red blood cells to keep hemoglobin concentrations above 10 g/dL in order to prevent anemia-induced myocardial ischemia. There are no data to support this practice. The hypothesis that vascular patients will tolerate a hemoglobin concentration of 9 g/dL was examined. METHODS Ninety-nine patients undergoing elective aortic and infrainguinal arterial reconstructions were prospectively randomized preoperatively to receive transfusions to maintain a hemoglobin level of either 10 g/dL or 9 g/dL. RESULTS Despite significantly different postoperative hemoglobin levels of 11.0 +/- 1.2 versus 9.8 +/- 1.3 g/dL (P <0.0001), there were no differences in mortality or cardiac morbidity rates or length of hospital stay. There were no differences in hemodynamic parameters. Oxygen delivery was lower in the group with lower hemoglobin levels, but there was no difference in O2 consumption between the groups. CONCLUSIONS A lower hemoglobin concentration was tolerated without adverse clinical outcome. Patients did not compensate for anemia by increased myocardial work, but by increasing O2 extraction in the peripheral tissues.

Implementation of an aortic screening program in clinical practice: Implications for the Screen for Abdominal Aortic Aneurysms Very Efficiently (SAAAVE) Act

OBJECTIVE Screening for abdominal aortic aneurysms (AAA) significantly reduces aneurysm-related death. In January 2007, the Federal government enacted Medicare coverage guideline to screen persons at risk for the presence of an AAA, the Screen for Abdominal Aortic Aneurysms Very Efficiently (SAAAVE) Act. The purpose of this study is to evaluate the efficacy and costs of a large scale screening effort for identifying AAAs in patients in clinical practice. METHODS A regional veterans affairs mandate for screening for AAA was implemented in February 2007. Data were extracted through the Northern California Veterans Affairs (VA) Service Network to identify veteran males 65-75 years of age who ever smoked at least 100 cigarettes during their lifetime. An AAA was defined as an aortic diameter 3.0 cm or greater. A Decision Support Systems software (LumiData, Minneapolis, Minn) package tracked true costs of conducting a large AAA screening protocol in the Northern California VA Health Care System. RESULTS A total of 2918 patients (average age, 71 +/- 6 years) were screened for AAA over a 1-year period from February 2007 to February 2008. An AAA was diagnosed in 5.1% (148/2918) of patients. Two hundred ninety patients out of the 2918 (9.9%) were inappropriately screened. The aneurysm distribution was as follows: 83% (123/148) of the aneurysms were 3.0-4.4 cm, 13% (19/148) were 4.5-5.5 cm, and 4.1% (6/148) were greater than 5.5 cm. Incidental findings of isolated iliac artery aneurysms were found in 0.1% (3/2918) of patients. The cost of AAA screening per patient is

Smoking cessation is associated with decreased mortality and improved amputation-free survival among patients with symptomatic peripheral artery disease

53. CONCLUSION The results of a large AAA screening effort in clinical practice reflect the results reported in the major clinical trials at a reasonable cost. The identification of large iliac artery aneurysms in the screening has not been previously reported.

Effects of Gender on Gene Expression in the Blood of Ischemic Stroke Patients

OBJECTIVE Although smoking cessation is recommended for all patients with peripheral artery disease, there are little data regarding the prevalence of smoking among patients at the time of angiography or the effect of smoking cessation on clinical outcomes. METHODS Consecutive patients with claudication or critical limb ischemia who underwent peripheral angiography from 2006 to 2013 were included in an observational cohort analysis. Smoking status was assessed at the time of angiography and during follow-up clinic visits. Kaplan-Meier analysis was used to assess the relationship between smoking cessation, mortality, and amputation-free survival. RESULTS Among 739 patients (423 men and 316 women; mean age, 60 ± 12 years), 204 (28%) remained active smokers at the time of lower extremity angiography. At the time of angiography, the mean number of cigarettes smoked per day was 16 ± 10, and the mean pack-years was 40 ± 25. During the course of the subsequent year, 61 patients (30%) successfully quit smoking and maintained continued abstinence. Baseline medication use between groups did not differ significantly. The mean ankle-brachial index was also similar for quitters vs nonquitters (0.53 ± 24 vs 0.49 ± 0.22; P = .3). During follow-up to 5 years, patients who quit smoking had significantly lower all-cause mortality (14% vs 31%; hazard ratio, 0.40; 95% confidence interval, 0.18-0.90) and improved amputation-free survival (81% vs 60%; hazard ratio, 0.43, 95% confidence interval, 0.22-0.86) compared with patients who continued smoking, with most of the difference driven by reduced mortality among patients who quit smoking. The findings remained significant on multivariable analysis. CONCLUSIONS Approximately one-third of active smokers with peripheral artery disease successfully quit smoking ≤ 1 year after lower extremity angiography. Patients who quit smoking have lower mortality and improved amputation-free survival compared with patients who continue smoking.

Nitinol Self-Expanding Stents vs. Balloon Angioplasty for Very Long Femoropopliteal Lesions

This study examined the effects of gender on RNA expression after ischemic stroke (IS). RNA obtained from blood of IS patients (n = 51; 153 samples at ≤ 3, 5, and 24 hours) and from matched controls (n = 52) were processed on Affymetrix microarrays. Analyses of covariance for stroke versus control samples were performed separately for both genders and the regulated genes for females compared with males. In all, 242, 227, and 338 male-specific genes were regulated at ≤ 3, 5, and 24 hours after IS, respectively, of which 59 were regulated at all time points. Overall, 774, 3,437, and 571 female-specific stroke genes were regulated at ≤ 3, 5, and 24 hours, respectively, of which 152 were regulated at all time points. Male-specific stroke genes were associated with integrin, integrin-liked kinase, actin, tight junction, Wnt/β-catenin, RhoA, fibroblast growth factors (FGF), granzyme, and tumor necrosis factor receptor (TNFR)2 signaling. Female-specific stroke genes were associated with p53, high-mobility group box-1, hypoxia inducible factor (HIF)1α, interleukin (IL)1, IL6, IL12, IL18, acute-phase response, T-helper, macrophage, and estrogen signaling. Cell death signaling was overrepresented in both genders, although the molecules and pathways differed. Gender affects gene expression in the blood of IS patients, which likely implies gender differences in immune, inflammatory, and cell death responses to stroke.

Outcomes of covered versus bare-metal balloon-expandable stents for aortoiliac occlusive disease.

Purpose To compare the patency rates and clinical outcomes of balloon angioplasty vs. nitinol stent placement for patients with short (≤150 mm) as compared to long (>150 mm) femoropopliteal (FP) occlusive lesions. Methods Between 2006 and 2011, 254 patients (134 men; mean age 68 years) underwent FP angioplasty. The majority of patients (64%) were treated for critical limb ischemia. One hundred thirty-nine (55%) patients had short FP lesions ≤150 mm, while 115 patients had long FP lesions >150 mm. The mean lesion length was 78±43 mm in the short FP lesion group and 254±58 mm in the long FP lesion group. Duplex ultrasound follow-up with a peak systolic velocity ratio ≥2.0 was used to define restenosis. Results The overall procedure success rate was 98%. One hundred forty-eight (58%) patients underwent stent placement. The mean number of stents deployed for treatment of short FP lesions was 1.0±0.4 vs. 2.0±0.7 for long FP lesions (p<0.001). The primary patency rate of short FP lesions treated with balloon angioplasty vs. stenting was 66% vs. 63% at 1 year (p=0.7). For long FP lesions, the 1-year primary patency rates of balloon angioplasty vs. stenting were 34% vs. 49% (p=0.006). Balloon angioplasty of long FP lesions was also associated with significantly lower assisted primary and secondary patency compared to stenting (p<0.05 for all comparisons). Sustained clinical improvement was >90% at 30 days but declined to 62% to 75% at 1 year. Conclusion Balloon angioplasty and stent placement result in similar patency rates and clinical outcomes for shorter to medium-length FP lesions. In comparison, stent placement in long FP lesions is associated with superior outcomes to balloon angioplasty, even when multiple stents are required. Procedure success and clinical improvement can be achieved in the majority of patients, but rates of restenosis remain high.

Ligation and extraanatomic arterial reconstruction for the treatment of aneurysms of the abdominal aorta

OBJECTIVE Randomized trials and retrospective data suggest that covered balloon-expandable (CBE) stents have better short-term patency compared with balloon-expandable bare-metal stents (BMSs) in the treatment of iliac artery disease. This study evaluated midterm outcomes of BMSs vs CBE stents placed in the common iliac artery (CIA) for aortoiliac occlusive disease. METHODS All endovascular interventions for symptomatic peripheral arterial occlusive disease performed at a single institution from 2006 to 2012 were reviewed. Patients undergoing stent placement in the CIA segment were included in the analysis. Demographic data, TransAtlantic Inter-Society Consensus (TASC) classification, stent type, patency, and limb reinterventions were compared. RESULTS For treatment of de novo distal aorta or CIA stenosis, 254 procedures were performed in 162 patients. BMSs were used in 190 arteries; CBE stents were used in 64 arteries. There was no difference in age, gender, or TASC classification between the two groups. Mean follow-up was 22 ± 16 months. Primary patency, assisted patency, and secondary patency were significantly better in the BMS group. CIAs treated with covered stents were more likely at 1 year or longer to require repeated intervention (hazard ratio, 2.5; 95% confidence interval, 1.2-5.3; P = .009). TASC classification did not predict need for reintervention in either group. Multivariate analysis revealed dual antiplatelet therapy to be the only other factor to affect patency during long-term follow-up. CONCLUSIONS In this study, BMSs had significantly better patency compared with CBE stents for treatment of aortoiliac occlusive disease. A randomized trial comparing patency as well as restenosis rates with long-term follow-up is needed to determine if there is any benefit from use of covered stents in the aortoiliac segment.

The X-Chromosome Has a Different Pattern of Gene Expression in Women Compared With Men With Ischemic Stroke

PURPOSE Since Blaisdell et al. first described axillobifemoral bypass and aortic exclusion to treat patients at high risk with abdominal aortic aneurysms in 1965, this approach has been controversial. To help define the appropriate application of this procedure, the recent experience of the authors was reviewed. METHODS Twenty-six patients underwent operation between March 1980 and August 1992. Mean age was 71 +/- 7 years. Average aneurysm diameter was 7.0 +/- 1.5 cm. Sixty-nine percent of the aneurysms were symptomatic; 21% were suprarenal. All patients had serious comorbid factors. All underwent axillobifemoral bypass with iliac artery ligation; the infrarenal aorta was also ligated in 62%. RESULTS There were two postoperative deaths (7.7%). One- and two-year survival rates were 59% and 38%, respectively. Three patients died of aneurysm rupture (11.5%); the aorta had not been ligated in two of these patients. The remaining late deaths were due to comorbid conditions. Extraanatomic bypass grafts thrombosed in five patients; no limbs were lost. CONCLUSIONS Axillobifemoral bypass without aortic ligation does not effectively reduce the risk of aneurysm rupture. However, axillobifemoral bypass with aortic ligation is an acceptable treatment for patients with severe medical problems and symptomatic, anatomically complicated, or large abdominal aortic aneurysms. Because the risk of aneurysm rupture is not completely eliminated, this procedure should be reserved for patients with high-risk aneurysms who would not tolerate direct aortic replacement.

Early duplex scanning after infrainguinal endovascular therapy

Background and Purpose— Differences in ischemic stroke between men and women have been mainly attributed to hormonal effects. However, sex differences in immune response to ischemia may exist. We hypothesized that differential expression of X-chromosome genes in blood immune cells contribute to differences between men and women with ischemic stroke. Methods— RNA levels of 683 X-chromosome genes were measured on Affymetrix U133 Plus2.0 microarrays. Blood samples from patients with ischemic stroke were obtained at ⩽3 hours, 5 hours, and 24 hours (n=61; 183 samples) after onset and compared with control subjects without symptomatic vascular diseases (n=109). Sex difference in X-chromosome gene expression was determined using analysis of covariance (false discovery rate ⩽0.05, fold change ≥1.2). Results— At ⩽3, 5, and 24 hours after stroke, there were 37, 140, and 61 X-chromosome genes, respectively, that changed in women; and 23, 18, and 31 X-chromosome genes that changed in men. Female-specific genes were associated with post-translational modification, small-molecule biochemistry, and cell–cell signaling. Male-specific genes were associated with cellular movement, development, cell-trafficking, and cell death. Altered sex specific X-chromosome gene expression occurred in 2 genes known to be associated with human stroke, including galactosidase A and IDS, mutations of which result in Fabry disease and Hunter syndrome, respectively. Conclusions— There are differences in X-chromosome gene expression between men and women with ischemic stroke. Future studies are needed to decipher whether these differences are associated with sexually dimorphic immune response, repair or other mechanisms after stroke, or whether some of them represent risk determinants.