Surgery or Endovascular Therapy for Chronic Limb-Threatening Ischemia

BACKGROUND

Patients with chronic limb-threatening ischemia (CLTI) require revascularization to improve limb perfusion and thereby limit the risk of amputation. It is uncertain whether an initial strategy of endovascular therapy or surgical revascularization for CLTI is superior for improving limb outcomes.

METHODS

In this international, randomized trial, we enrolled 1830 patients with CLTI and infrainguinal peripheral artery disease in two parallel-cohort trials. Patients who had a single segment of great saphenous vein that could be used for surgery were assigned to cohort 1. Patients who needed an alternative bypass conduit were assigned to cohort 2. The primary outcome was a composite of a major adverse limb event - which was defined as amputation above the ankle or a major limb reintervention (a new bypass graft or graft revision, thrombectomy, or thrombolysis) - or death from any cause.

RESULTS

In cohort 1, after a median follow-up of 2.7 years, a primary-outcome event occurred in 302 of 709 patients (42.6%) in the surgical group and in 408 of 711 patients (57.4%) in the endovascular group (hazard ratio, 0.68; 95% confidence interval [CI], 0.59 to 0.79; P<0.001). In cohort 2, a primary-outcome event occurred in 83 of 194 patients (42.8%) in the surgical group and in 95 of 199 patients (47.7%) in the endovascular group (hazard ratio, 0.79; 95% CI, 0.58 to 1.06; P = 0.12) after a median follow-up of 1.6 years. The incidence of adverse events was similar in the two groups in the two cohorts.

CONCLUSIONS

Among patients with CLTI who had an adequate great saphenous vein for surgical revascularization (cohort 1), the incidence of a major adverse limb event or death was significantly lower in the surgical group than in the endovascular group. Among the patients who lacked an adequate saphenous vein conduit (cohort 2), the outcomes in the two groups were similar. (Funded by the National Heart, Lung, and Blood Institute; BEST-CLI ClinicalTrials.gov number, NCT02060630.).

Structures of recombinant native and E202Q mutant human acetylcholinesterase complexed with the snake-venom toxin fasciculin-II

Structures of recombinant wild-type human acetylcholinesterase and of its E202Q mutant as complexes with fasciculin-II, a 'three-finger' polypeptide toxin purified from the venom of the eastern green mamba (Dendroaspis angusticeps), are reported. The structure of the complex of the wild-type enzyme was solved to 2.8 A resolution by molecular replacement starting from the structure of the complex of Torpedo californica acetylcholinesterase with fasciculin-II and verified by starting from a similar complex with mouse acetylcholinesterase. The overall structure is surprisingly similar to that of the T. californica enzyme with fasciculin-II and, as expected, to that of the mouse acetylcholinesterase complex. The structure of the E202Q mutant complex was refined starting from the corresponding wild-type human acetylcholinesterase structure, using the 2.7 A resolution data set collected. Comparison of the two structures shows that removal of the charged group from the protein core and its substitution by a neutral isosteric moiety does not disrupt the functional architecture of the active centre. One of the elements of this architecture is thought to be a hydrogen-bond network including residues Glu202, Glu450, Tyr133 and two bridging molecules of water, which is conserved in other vertebrate acetylcholinesterases as well as in the human enzyme. The present findings are consistent with the notion that the main role of this network is the proper positioning of the Glu202 carboxylate relative to the catalytic triad, thus defining its functional role in the interaction of acetylcholinesterase with substrates and inhibitors.

Mesenteric revascularization: management and outcomes in the United States, 1988-2006

BACKGROUND

Recent reports have suggested that angioplasty, with and without stenting (PTA/S), may have a lower perioperative mortality rate than open surgery for revascularization of acute (AMI) and chronic mesenteric ischemia (CMI). It is unclear if there has been nationwide adoption of this methodology or whether there is actually a mortality benefit.

METHODS

We identified all patients undergoing surgical (bypass, endarterectomy, or embolectomy) or PTA/S mesenteric revascularization from the Nationwide Inpatient Sample from 1988 to 2006. A diagnosis by International Classification of Diseases, 9th Revisioncoding of AMI or CMI was required for inclusion. We evaluated trends in management during this period and compared in-hospital death and complications between surgical bypass and PTA/S for the years 2000 to 2006.

RESULTS

From 1988 to 2006, there were 6342 PTA/S and 16,071 open surgical repairs overall. PTA/S increased steadily, surpassing all surgery for CMI in 2002. PTA/S for AMI has also increased and surpassed bypass in 2002 but has not surpassed all surgical procedures for AMI even in 2006. The mortality rate was lower after PTA/S than after bypass for CMI (3.7% vs 13%, P < .01) and AMI (16% vs 28%, P < .01). Bowel resection was more common after bypass than PTA/S for CMI (7% vs 3%, P < .01). This subgroup showed an increased in-hospital mortality rate for both repair types (54% and 25%, respectively).

CONCLUSION

PTA/S is being used with increasing frequency for revascularization of CMI and AMI. The lower in-hospital mortality rate for patients, as they are currently being selected, shows that PTA/S is appropriate therapy for selected patients with CMI. Longitudinal data are needed to determine the durability of this benefit. The greater proportion of patients undergoing bowel resection with bypass for AMI suggests a more advanced level of ischemia in this group, making comparison with PTA/S difficult. However, PTA/S may be useful in selected patients with AMI and appropriate anatomy. Further data with greater detail regarding symptomatology and anatomy will clarify appropriate patient selection.

Decrease in total aneurysm-related deaths in the era of endovascular aneurysm repair

OBJECTIVE

With the expansion of elective abdominal aortic aneurysm (AAA) repair after the introduction of endovascular aneurysm repair (EVAR), there is a concern that even with a lower operative mortality there could be an increasing number of aneurysm-related deaths. To evaluate this, we looked at national trends in AAA repair volume as well as mortality rates after intact and ruptured AAA repair encompassing the introduction of EVAR.

METHODS

Patients with intact or ruptured AAA undergoing open repair or EVAR and all those with a diagnosis of ruptured AAA were identified within the 1993 to 2005 Nationwide Inpatient Sample database using International Classification of Diseases, 9th Revision, diagnosis and procedure codes. The number of repairs, number of rupture diagnoses without repair, number of deaths, and associated mortality rates were measured for each year of the database. Outcomes (mean annual volumes) were compared from the pre-EVAR era (1993 to 1998) with the post-EVAR era (2001 to 2005).

RESULTS

Since its introduction, EVAR increased steadily and accounted for 56% of repairs yet only 27% of the deaths for intact repairs in 2005. The mean annual number of intact repairs increased from 36,122 in the pre-EVAR era to 38,901 in the post-EVAR era, whereas the mean annual number of deaths related to intact AAA repair decreased from 1693 pre-EVAR to 1207 post-EVAR (P < .0001). Mortality for all intact AAA repair decreased from 4.0% to 3.1% (P < .0001) pre-EVAR and post-EVAR, but open repair mortality was unchanged (open repair, 4.7% to 4.5%, P = .31; EVAR, 1.3%). During the same time, the mean annual number of ruptured repairs decreased from 2804 to 1846, and deaths from ruptured AAA repairs decreased from 2804 to 1846 (P < .0001). Mortality for ruptured AAA repair decreased from 44.3% to 39.9% (P < .0001) pre-EVAR and post-EVAR (open repair, 44.3% to 39.9%, P < .001; EVAR, 32.4%). The overall mean annual number of ruptured AAA diagnoses (9979 to 7773, P < .0001) and overall mean annual deaths from a ruptured AAA decreased post-EVAR (5338 to 3901, P < .0001).

CONCLUSION

Since the introduction of EVAR, the annual number of deaths from intact and ruptured AAA has significantly decreased. This coincided with an increase in intact AAA repair after the introduction of EVAR and a decrease in ruptured AAA diagnosis and repair volume.

Body mass index: surgical site infections and mortality after lower extremity bypass from the National Surgical Quality Improvement Program 2005-2007

BACKGROUND

Patients undergoing lower extremity bypass are at high risk for surgical site infections (SSI). We examined lower extremity bypasses by graft origin and body mass index (BMI) classification to analyze differences in postoperative mortality and SSI occurrence.

METHODS

The 2005-2007 National Surgical Quality Improvement Program (NSQIP), a multi-institutional risk-adjusted database, was queried to compare perioperative mortality (30-day), overall morbidity, and SSIs after lower extremity arterial bypass for peripheral arterial disease. Bypass was stratified by graft origin as aortoiliac, femoral, or popliteal. Patient demographics, comorbidities, operative, and postoperative occurrences were analyzed.

RESULTS

There were 7,595 bypasses performed (1,596 aortoiliac, 5,483 femoral, and 516 popliteal). Mortality was similar regardless of bypass origin (2.8%, 2.4%, and 2.7%; p = 0.57). SSIs occurred in 11% of overall cases (10%, 11%, and 11%; p = 0.47). Graft failure was significantly associated with postoperative SSI occurrence (odds ratio [OR] = 2.4, 95% confidence interval [CI] 1.9-3.1, p < 0.001), as was postoperative sepsis (OR = 6.5, 95% CI 5.1-8.3, p < 0.001). Independent predictors of mortality were age, aortoiliac bypass origin, underweight, normal weight, morbid obesity (compared to overweight and obese), end-stage renal disease, poor preoperative functional status, preoperative sepsis, chronic obstructive pulmonary disease, hypoalbuminemia, and cardiac disease. Independent predictors of SSI were obesity, diabetes, poor preoperative functional status, a history of smoking, and female gender.

CONCLUSION

SSIs occur frequently after lower extremity bypass regardless of bypass origin and are associated with early graft failure and sepsis. Obesity predicts postoperative SSI. Mortality risk was greatest in the underweight, followed by morbidly obese and normal-weight patients, while overweight and mild to moderate obesity were associated with the lowest mortality.

Risk prediction for perioperative mortality of endovascular vs open repair of abdominal aortic aneurysms using the Medicare population

OBJECTIVES

The impact of risk factors upon perioperative mortality might differ for patients undergoing open vs endovascular repair (EVAR) of abdominal aortic aneurysms (AAA). In order to investigate this, we developed a differential predictive model of perioperative mortality after AAA repair.

METHODS

A total of 45,660 propensity score matched Medicare beneficiaries undergoing elective open or endovascular AAA repair from 2001 to 2004 were studied. Using half the dataset we developed a multiple logistic regression model for a matched cohort of open and EVAR patients and used this to derive an easily evaluable risk prediction score. The remainder of the dataset formed a validation cohort used to confirm results.

RESULTS

The derivation cohort included 11,415 open and 11,415 endovascular repairs. Perioperative mortality was 5.3% and 1.8%, respectively. Independent predictors of mortality (relative risk [RR], 95% confidence interval [CI]) were open repair (3.2, 2.7-3.8); age (71-75 years 1.2, 0.9-1.6; 76-80 years 1.9, 1.4-2.5; >80 years 3.1, 2.4-4.2); female gender (1.5, 1.3-1.8); dialysis (2.6, 1.5-4.6); chronic renal insufficiency (2.0, 1.6-2.6); congestive heart failure (1.7, 1.5-2.1); and vascular disease (1.3, 1.2-1.6). There were no differential predictors of mortality across the two procedures. A simple scoring system was developed from a logistic regression model fit to both endovascular and open patients (area under the receiver operator curve [ROC] curve of 72.6) from which low, medium, and high risk groups were developed. The absolute predicted mortality ranged from 0.7% for an EVAR patient </=70 years of age with no comorbidities to 38% for an open patient >80 with all the comorbidities considered. Although relative risk was similar among age groups, the absolute difference was greater for older patients (with higher baseline risk).

CONCLUSION

Mortality after AAA repair is predicted by comorbidities, gender, and age, and these predictors have similar effects for both methods of AAA repair. This simple scoring system can predict repair mortality for both treatment options and thus may help guide clinical decisions.

Results for primary bypass versus primary angioplasty/stent for intermittent claudication due to superficial femoral artery occlusive disease

BACKGROUND

Percutaneous transluminal angioplasty ± stent (PTA/S) and surgical bypass are both accepted treatments for claudication due to superficial femoral artery (SFA) occlusive disease. However, long-term results comparing these modalities for primary intervention in patients who have had no prior intervention have not been reported. We report our results with 3-year follow-up.

METHODS

We reviewed all lower extremity bypass procedures at Beth Israel Deaconess Medical Center from 2001 through 2009 and all PTA/S performed from 2005 through 2009 for claudication. We excluded all limb salvage procedures and included only those that were undergoing their first intervention for claudication due to SFA disease. We recorded patient demographics, comorbidities, perioperative medications, TASC classification, and runoff. Outcomes included complications, restenosis, symptom recurrence, reinterventions, major amputation, and mortality.

RESULTS

We identified 113 bypass grafts and 105 PTA/S of femoral-popliteal lesions without prior interventions. Bypasses were above the knee in 62% (45% vein) and below the knee in 38% (100% vein). Mean age was 63 (bypass) versus 69 (PTA/S; P < .01). Mean length of stay (LOS) was 3.9 versus 1.2 days (P < .01). Bypass grafts were used less for TASC A (17% vs 40%; P < .01) and more for TASC C (36% vs 11%; P < .01) and TASC D (13% vs 3%; P < .01) lesions. There were no differences in perioperative (2% vs 0%; not significant [NS]) or 3-year mortality (9% vs 8%; NS). Wound infection was higher with bypass (16% vs 0%; P < .01). None involved grafts. Bypass showed improved freedom from restenosis (73% vs 42% at 3 years; hazard ratio [HR], 0.4; 95% confidence interval [CI], .23-.71), symptom recurrence (70% and 36% at 3 years; HR, 0.37; 95% CI, .2-.56), and freedom from symptoms at last follow-up (83% vs 49%; HR, 0.18; 95% CI, .08-.40). There was no difference in freedom from reintervention (77% vs 66% at 3 years; NS). Multivariable analysis of all patients showed that restenosis was predicted by PTA/S (HR, 2.5; 95% CI, 1.4-4.4) and TASC D (HR, 3.7; 95% CI, 3.5-9) lesions. Recurrence of symptoms was similarly predicted by PTA/S (HR, 3.0; 95% CI, 1.8-5) and TASC D lesions (HR, 3.1; 95% CI, 1.4-7). Statin use postoperatively was predictive of patency (HR, 0.6; 95% CI, .35-.97) and freedom from recurrent symptoms (HR, 0.6; 95% CI, .36-.93).

CONCLUSIONS

Surgical bypass for the primary treatment of claudication showed improved freedom from restenosis and symptom relief despite treatment of more extensive disease, but was associated with increased LOS and wound infection. Statins improved freedom from restenosis and symptom recurrence overall.

Long-term effects of calcium carbonate and 2.5 mEq/liter calcium dialysate on mineral metabolism

Many investigators have shown that calcium carbonate (CaCO3) is an effective phosphate binder which also prevents the potential disabling effects of aluminum (Al) accumulation. However, hypercalcemia may develop in a substantial numbers of patients. Thus, to control serum phosphate (PO4) and prevent hypercalcemia, we performed studies in 21 patients on maintenance hemodialysis in which, in addition to the oral administration of CaCO3, the concentration of calcium (Ca) in the dialysate was reduced from 3.25 to 2.5 mEq/liter. The studies were divided in three periods: I. control, on Al-binders (one month); II. no Al-binders (one month); III. CaCO3 (seven months). Blood was obtained three times/week before dialysis for the first five months of the study and once a week for the remaining four months. During the control period, the mean serum calcium was 8.86 +/- 0.08 mg/dl. The value decreased to 8.65 +/- 0.07 mg/dl when phosphate binders containing aluminum were discontinued, and increased to 9.19 +/- 0.07 mg/dl (P less than 0.001 compared to period II) during oral supplementation with calcium carbonate. The mean serum phosphorus was 5.03 +/- 0.07 mg/dl during the control period, and increased to 7.29 +/- 0.91 mg/dl (P less than 0.001) after phosphate binders were discontinued. It decreased to 4.95 +/- 0.06 mg/dl (P less than 0.001) with the administration of calcium carbonate. During CaCO3 administration, serum Al decreased from 64.2 +/- 8.5 to 37.1 +/- 3.6 and 25.1 +/- 3.0 micrograms/liter (P less than 0.001) at three and seven months, respectively. Serum parathyroid hormone (PTH) decreased by 20%.(ABSTRACT TRUNCATED AT 250 WORDS)

Open and endovascular repair of type B aortic dissection in the Nationwide Inpatient Sample

BACKGROUND

The use of stent grafts and mortality of stent graft repair of type B thoracic aortic dissection (T(B)AD) is not well defined. We sought to determine national estimates for the use and mortality of thoracic endovascular aortic repair (TEVAR) for T(B)AD in the United States.

METHODS

Records of the Nationwide Inpatient Sample (NIS) database between 2005 and 2007 were examined. International Classification of Diseases, 9th edition (ICD-9) diagnosis codes were used to select patients who underwent open or TEVAR with a stent graft for a diagnosis of thoracic aortic dissection or thoracoabdominal aortic dissection. We excluded patients with a diagnosis code for aortic aneurysm and those with procedure codes for cardioplegia or for operations on heart vessels or valves, which were considered type A dissections (T(A)AD). The remaining patients were considered as T(B)AD. We compared demographics and comorbidities, as well as adjusted complications and mortality rates, between patients undergoing TEVAR vs open repair.

RESULTS

We identified an estimated 10,466 repairs for dissection of the thoracic or thoracoabdominal aorta (open, 8659; TEVAR, 1818). Of these, 464 had a diagnosis of aortic aneurysm, and 5002 patients were considered T(A)AD. Of nonaneurysmal dissections, 5000 repairs were considered T(B)AD (open, 3619; TEVAR, 1381). The endovascular patients were older and had greater comorbidities, although only cardiac disease, renal failure, hypertension, and peripheral vascular disease were statistically significant. In-hospital mortality was 19% for open repair vs 10.6% for TEVAR (odds ratio [OR], 2.24; 95% confidence interval [CI], 1.36-3.67; P < .01). In-hospital mortality was significantly higher with open repairs coded as emergent admissions (20.1% vs 13.1%; P = .03), but did not reach statistical significance for elective admissions (12.3% vs 4.8%; P = .09). Cardiac complications (12.4% vs 4.9%, P < .01), respiratory complications (7.7% vs 4.3%, P = .02), genitourinary complications (9.0% vs 2.5%, P < .01), hemorrhage (14.0% vs 2.8%, P < .01), and acute renal failure (32.1% vs 17.2%, P < .01) were more frequent in the open repair group. Median length of stay was greater in the open repair group (10.7 vs 8.3 days, P < .01).

CONCLUSION

For patients with a diagnosis of T(B)AD who undergo repair, the endovascular approach is being used for older patients with greater comorbidities, yet has reduced morbidity and in-hospital mortality. The use of endovascular stent graft repair for type B thoracic aortic dissection merits further longitudinal analysis.

Accurate mass liquid chromatography/mass spectrometry on quadrupole orthogonal acceleration time-of-flight mass analyzers using switching between separate sample and reference sprays. 2. Applications using the dual-electrospray ion source

A new electrospray dual sprayer, LockSpray, was developed for accurate mass measurements on a quadrupole orthogonal acceleration time-of-flight mass spectrometer (oa-Q-ToF). With the dual-sprayer ion source, both sprays are orthogonal to each other. A mechanism similar to the one employed on the multiplexed electrospray source (MUX) allows switching between reference and sample sprayer. The reference sprayer is optimized for low flow rates, whereas the sample sprayer is a conventional Z-spray type sprayer. Earlier work using a modified MUX ion source on an orthogonal acceleration time-of-flight instrument showed promising results. In this paper, examples obtained with the LockSpray, specifically designed for accurate mass measurements on an oa-Q-ToF, are presented. The examples include results obtained for the identification of impurities in drug substances such as cimetidine and rosiglitazone, using accurate mass tandem mass spectrometry in both positive and negative ion electrospray modes. Good mass accuracies, i.e., within 2 mDa of the theoretical value, were obtained in MS and MS/MS operation.

Thirty-day mortality and late survival with reinterventions and readmissions after open and endovascular aortic aneurysm repair in Medicare beneficiaries

OBJECTIVES

Late survival is similar after open and endovascular abdominal aortic aneurysm (AAA) repair (EVAR), despite a perioperative benefit with EVAR. AAA-related reinterventions are more common after EVAR, whereas laparotomy-related reinterventions are more common after open repair. The effect of reinterventions on survival, however, is unknown. We therefore evaluated the rate of reinterventions and readmission after initial AAA repair, 30-day mortality, and the effect on long-term survival.

METHODS

We identified AAA-related and laparotomy-related reinterventions for propensity score-matched cohorts of 45,652 Medicare beneficiaries undergoing EVAR and open repair from 2001 to 2004. Follow-up was up to 6 years. Hospitalizations for ruptured AAA without repair and for bowel obstruction or ventral hernia without abdominal surgery were also recorded. Event rates were calculated per year and are presented through 6 years of follow-up as events per 100 person-years. Thirty-day mortality was calculated for each reintervention or readmission.

RESULTS

Through 6 years, overall reinterventions or readmissions were similar between repair methods but slightly more common after EVAR (7.6 vs 7.0/100 person-years; relative risk [RR], 1.1; P < .001). Overall 30-day mortality with any reintervention or readmission was 9.1%. EVAR patients had more ruptures (0.50 vs 0.09 [RR, 5.7; P < .001]), with a mortality of 28%, but these were uncommon. EVAR patients also had more AAA-related reinterventions through 6 years (3.7 vs 0.9 [RR, 4.0; P < .001]; mortality, 5.6%), most of which were minor endovascular reinterventions (2.4 vs 0.2 [RR, 11.4; P < .001]), with a 30-day mortality of 3.0%. However, minor open (0.8 vs 0.5 [RR, 1.4; P < .001]; mortality, 6.9%) and major reinterventions (0.4 vs 0.2 [RR, 2.4; P < .001]; mortality, 12.1%) were also more common after EVAR than open repair. Conversely, EVAR patients had fewer laparotomy-related reinterventions than open patients (1.4 vs 3.0 [RR, 0.5; P < .001]; mortality, 8.1%) and readmissions without surgery (2.0 vs 2.7 [RR, 0.7; P < .001]; mortality 10.9%). Overall, reinterventions or readmission accounted for 9.6% of all EVAR deaths and 7.6% of all open repair deaths in the follow-up period (P < .001).

CONCLUSIONS

Reintervention and readmission are slightly higher after EVAR. Survival is negatively affected by reintervention or readmission after EVAR and open surgery, which likely contributes to the erosion of the survival benefit of EVAR over time.

The impact of body mass index on perioperative outcomes of open and endovascular abdominal aortic aneurysm repair from the National Surgical Quality Improvement Program, 2005-2007

OBJECTIVES

Obesity and morbid obesity have been shown to increase wound infections and occasionally mortality after many surgical procedures. Little is known about the relative impact of body mass index (BMI) on these outcomes after open (OAR) and endovascular abdominal aortic aneurysm repair (EVAR).

METHODS

The 2005-2007 National Surgical Quality Improvement Program (NSQIP), a multi-institutional risk-adjusted database, was retrospectively queried to compare perioperative mortality (in-hospital or 30-day) and postoperative wound infections after OAR and EVAR. Patient demographics, comorbidities, and operative details were analyzed. Obesity was defined as a BMI >30 kg/m(2) and morbid obesity as a BMI >40 kg/m(2). Outcomes were compared with t test, Wilcoxon rank sum, χ(2), and multivariate logistic regression.

RESULTS

There were 2097 OARs and 3358 EVARs. Compared with EVAR, OAR patients were younger, more likely to be women (26% vs 17%, P < .001), and less obese (27% vs 32%, P < .001). Mortality was 3.7% after OAR vs 1.2% after EVAR (risk ratio, 3.1; P < .001), and overall morbidity was 28% vs 12%, respectively (relative risk, 2.3; P < .001). Morbidly obese patients had a higher mortality for both OAR (7.3%) and EVAR (2.4%) than obese patients (3.9% OAR; 1.5% EVAR) or nonobese patients (3.7% OAR; 1.1% EVAR). Obese patients had a higher rate of wound infection vs nonobese after OAR (6.3% vs 2.4%, P < .001) and EVAR (3.3% vs 1.5%, P < .001). Morbid obesity predicted death after OAR but not after EVAR, and obesity was an independent predictor of wound infection after OAR and EVAR.

CONCLUSIONS

Morbid obesity confers a worse outcome for death after abdominal aortic aneurysm repair. Obesity is also a risk factor for infectious complications after OAR and EVAR. Obese patients and, particularly, morbidly obese patients should be treated with EVAR when anatomically feasible.

Accurate mass liquid chromatography/mass spectrometry on orthogonal acceleration time-of-flight mass analyzers using switching between separate sample and reference sprays. 1. Proof of concept

This paper describes the use of two separate electrosprays for introducing sample and reference for accurate mass liquid chromatography/mass spectrometry (LC/MS) on an orthogonal acceleration time-of-flight mass analyzer. This is carried out using an adaptation of the multiplexed electrospray ion source in which only two of the sprays are utilized. Results are shown for the positive ion detection of trace-level components in complex matrixes and good mass accuracies are obtained, even for very low level components. An example of accurate mass measurements obtained using negative ion LC/MS is also shown. To obtain additional structural information, an example of cone voltage fragmentation is included and shows that good mass accuracy can be obtained for both precursor and fragment ions.

Prosthetic graft infections involving the femoral artery

BACKGROUND

Prosthetic graft infection is a major complication of peripheral vascular surgery. We investigated the experience of a single institution over 10 years with bypass grafts involving the femoral artery to determine the incidence and risk factors for prosthetic graft infection.

METHODS

A retrospective cohort single-institution review of prosthetic bypass grafts involving the femoral artery from 2001 to 2010 evaluated patient demographics, body mass index, comorbidities, indications, location of bypass, type of prosthetic material, case urgency, and previous ipsilateral bypass or percutaneous interventions and evaluated the incidence of graft infections, amputations, and mortality.

RESULTS

There were 496 prosthetic grafts identified with a graft infection rate of 3.8% (n = 19) at a mean follow-up of 27 months. Multivariable analysis showed that redo bypass (hazard ratio [HR], 5.8; 95% confidence interval [CI], 2.2-15.0), active infection at the time of bypass (HR, 5.2; 95% CI, 1.9-14.2), female gender (HR, 4.5; 95% CI, 1.6-12.7), and diabetes mellitus (HR, 4.6; 95% CI, 1.5-14.3) were significant predictors of graft infection. Graft infection was predictive of major lower extremity amputation (HR, 9.8; 95% CI, 3.5-27.1), as was preoperative tissue loss (HR, 4.7; 95% CI, 1.8-11.9). Graft infection did not predict long-term mortality; however, chronic renal insufficiency (HR, 2.3; 95% CI, 1.6-3.4), tissue loss (HR, 1.4; 95% CI, 1.0-1.9), and active infection (HR, 2.3; 95% CI, 1.6-3.4) did. Infected grafts were removed 79% of the time. Staphylococcus epidermidis (37%) and methicillin-sensitive Staphylococcus aureus (26%) were the most common pathogens isolated.

CONCLUSIONS

Redo bypass, female gender, diabetes, and active infection at the time of bypass are associated with a higher risk for prosthetic graft infection and major extremity amputation but do not confer an increased risk of mortality. Autologous vein for lower extremity bypass and endovascular interventions should be considered when feasible in high-risk patients.

High throughput liquid chromatography/mass spectrometric analyses using a novel multiplexed electrospray interface

A novel four- channel multiplexed electrospray liquid chromatography interface is described. This device has been used to analyse both single components and mixtures by liquid chromatography/mass spectrometry (LC/MS) as well as synthetic samples prepared by automated procedures. These data provided unambiguous molecular weight assignments to both major components and synthetic by-products in these samples. In this work particular attention has also been paid to the elimination of interchannel crosstalk. Copyright 1999 John Wiley & Sons, Ltd.

Population-based outcomes following endovascular and open repair of ruptured abdominal aortic aneurysms

PURPOSE

To evaluate national outcomes after endovascular and open surgical repair of ruptured abdominal aortic aneurysms (rAAA).

METHODS

The Nationwide Inpatient Sample was interrogated to identify all repairs between 2000 and 2005 for rAAA based on ICD-9 codes. In the study period, 2323 patients (1794 men; median age 75 years, range 45-98) with rAAAs had endovascular repair, while 26,106 patients (20,311 men; median age 73 years, range 22-99) had an open procedure. Outcomes included in-hospital mortality, length of stay (LOS), complications, and hospitalization charge. A secondary analysis was performed to compare outcomes from low-, medium-, and high-volume institutions based on annual rAAA repair volume.

RESULTS

Patients in the endovascular group were significantly older (p<0.05). Mortality was 41% overall: 33% and 41% for endovascular versus open repair, respectively (p<0.001). Mortality after endovascular repair was lower than open surgery for patients >or=70 years (36% versus 47%, p<0.001), but not for those <70 years (24% versus 30%, p = 0.15). LOS was shorter after endovascular repair (7 versus 9 days, p<0.001). Respiratory complications (8% versus 4%, p<0.05) and acute renal failure were more common following open repair (30% versus 23%, p<0.01). Costs were similar (endo $73,590 versus open $67,287, p = 0.15). Mortality decreased as hospital surgical volume increased (low 44%, medium 39%, high 38%; p<0.001). Over time, endovascular repair utilization increased more rapidly at high-volume centers, and a lower mortality was seen with endovascular repair at high-volume compared to low-volume hospitals (22% versus 44%, p<0.001). Multivariate predictors of mortality were age, female gender, lower hospital surgical volume, open repair, and year of surgery.

CONCLUSION

This population-based study found that mortality associated with rAAAs may be improved by the performance of endovascular repair, especially in older patients. Mortality after rAAA for both endovascular and open repairs was also lower at high-volume institutions.

Outcomes following infrapopliteal angioplasty for critical limb ischemia

OBJECTIVE

Infrapopliteal angioplasty (percutaneous transluminal angioplasty [PTA]) is routinely used to treat critical limb ischemia (CLI) despite limited data on long-term outcomes.

METHODS

We reviewed all patients undergoing infrapopliteal PTA for CLI from 2004 to 2012 stratified by TransAtlantic Inter-Society Consensus (TASC) class. Outcomes included restenosis, primary patency, reintervention (w/PTA or bypass), amputation, procedural complications, wound healing, and survival.

RESULTS

Infrapopliteal PTA (stenting 14%, multilevel intervention 50%) was performed in 459 limbs of 413 patients (59% male) with a technical success of 93% and perioperative complications in 11%. TASC class was 16% A, 22% B, 27% C, and 34% D. Multilevel interventions were performed in 50% of limbs and were evenly distributed among all TASC classes. All technical failures were TASC D lesions. Mean follow-up was 15 months; 5-year survival was 49%. One- and 5-year primary patency was 57% and 38% and limb salvage was 84% and 81%, respectively. Restenosis was associated with TASC C (hazard ratio [HR], 2.2; 95% CI, 1.2-3.9; P = .010) and TASC D (HR, 2.4; 95% CI, 1.3-4.4; P = .004) lesions. Amputation rates were higher in patients who were not candidates for bypass (HR, 4.4; 95% CI, 2.6-7.5; P < .001) and with TASC D lesions (HR, 3.8; 95% CI, 1.1-12.5; P = .03). Unsuitability for bypass was also predictive of repeat PTA (HR, 1.8; 95% CI, 1.0-3.4; P = .047). Postoperative clopidogrel use was associated with lower rates of any revascularization (HR, 0.46; 95% CI, 0.25-0.83; P = .011).

CONCLUSIONS

Infrapopliteal PTA is effective primary therapy for TASC A, B, and C lesions. Surgical bypass should be offered to patients with TASC D disease who are suitable candidates. Multilevel intervention does not adversely affect outcome.

Stroke and death after carotid endarterectomy and carotid artery stenting with and without high risk criteria

OBJECTIVE

Centers for Medicare and Medicaid Services (CMS) reimbursement criteria for carotid artery stenting (CAS) require that patients be high surgical risk or enrolled in a clinical trial. This may bias comparisons of CAS and carotid endarterectomy (CEA). We evaluate mortality and stroke following CAS and CEA stratified by medical high risk criteria.

METHODS

The Nationwide Inpatient Sample (2004-2007) was queried by ICD-9 code for CAS and CEA with diagnosis of carotid artery stenosis. Medical high risk criteria were identified for each patient including patients undergoing a coronary artery bypass and/or valve repair (CABG/V) during the same admission. Symptom status was defined by history of stroke, transient ischemic attack (TIA), and/or amarosis fugax. The primary outcome was postoperative death, stroke (complication code 997.02), and combined stroke or death, stratified by high risk vs non-high risk status and symptom status.

RESULTS

Patient totals of 56,564 (10.5%) CAS and 482,394 (89.5%) CEA were identified. Half of the patients in each group were high risk. CABG/V was performed less commonly with CAS than CEA (2.8% vs 4.0%, P < .001). Patients undergoing CAS were more likely symptomatic than those undergoing CEA (13.1% vs 9.4%, P < .001). Mortality was higher after CAS than CEA for both high risk and non-high risk patients. Stroke was also higher after CAS for both high risk and non-high risk patients. Combined stroke or death was higher after CAS again for both high risk (asymptomatic 1.5% vs 1.2%, P < .05, symptomatic 14.4% vs 6.9%, P < .001) and non-high risk (asymptomatic 1.8% vs 0.6%, P < .001, symptomatic 11.8% vs 4.9%, P < .001). Combined stroke or death for patients undergoing CABG/V during the same admission was similar for CAS and CEA (4.8% vs 3.2%, P = .19). Multivariate predictors of combined stroke or death adjusted for age and gender included CAS vs CEA (odds ratio [OR] 2.4, P < .001), symptom status (OR 6.8, P < .001), high risk (OR 1.6, P < .001), and earlier year of procedure (OR 1.1, P < .01).

CONCLUSIONS

In the United States from 2004 to 2007, CAS has a higher risk of stroke and death than CEA after adjustment for medical high risk criteria. Further analysis with prospective assessment of risk factors is needed to guide appropriate patient selection for CEA and CAS in the general population.

Outcomes of thoracic endovascular aortic repair using aortic arch chimney stents in high-risk patients

BACKGROUND

Aortic arch disease is a challenging clinical problem, especially in high-risk patients, in whom open repair can have morbidity and mortality rates of 30% to 40% and 2% to 20%, respectively. Aortic arch chimney (AAC) stents used during thoracic endovascular aortic repair (TEVAR) are a less invasive treatment strategy than open repair, but the current literature is inconclusive about the role of this technology. The focus of this analysis is on our experience with TEVAR and AAC stents.

METHODS

All TEVAR procedures performed from 2002 to 2015 were reviewed to identify those with AAC stents. Primary end points were technical success and 30-day and 1-year mortality. Secondary end points included complications, reintervention, and endoleak. Technical success was defined as a patient's surviving the index operation with deployment of the AAC stent at the intended treatment zone with no evidence of type I or type III endoleak on initial postoperative imaging. The Kaplan-Meier method was used to estimate survival.

RESULTS

Twenty-seven patients (age, 69 ± 12 years; male, 70%) were identified, and all were described as being at prohibitive risk for open repair by the treating team. Relevant comorbidity rates were as follows: coronary artery disease/myocardial infarction, 59%; oxygen-dependent emphysema, 30%; preoperative creatinine concentration >1.8 mg/dL, 19%; and congestive heart failure, 15%. Presentations included elective (67%; n = 18), symptomatic (26%; n = 7), and ruptured (7%; n = 2). Eleven patients (41%) had prior endovascular or open arch/descending thoracic repair. Indications were degenerative aneurysm (49%), chronic residual type A dissection with aneurysm (15%), type Ia endoleak after TEVAR (11%), postsurgical pseudoaneurysm (11%), penetrating ulcer (7%), and acute type B dissection (7%). Thirty-two brachiocephalic vessels were treated: innominate (n = 7), left common carotid artery (LCCA; n = 24), and left subclavian artery (n = 1). Five patients (19%) had simultaneous innominate-LCCA chimneys. Brachiocephalic chimney stents were planned in 75% (n = 24), with the remainder placed for either LCCA or innominate artery encroachment (n = 8). Overall technical success was 89% (one intraoperative death, two persistent type Ia endoleaks in follow-up). The 30-day mortality was 4% (n = 1; intraoperative death of a patient with a ruptured arch aneurysm), and median length of stay was 6 (interquartile range, 4-9) days. Seven (26%) patients experienced a major complication (stroke, three [all with unplanned brachiocephalic chimney]; respiratory failure, three; and death, one). Nine (33%) patients underwent aorta-related reintervention, and no chimney occlusion events occurred during follow-up (median follow-up, 9 [interquartile range, 1-23] months). The 1-year and 3-year survival is estimated to be 88% ± 6% and 69% ± 9%, respectively.

CONCLUSIONS

TEVAR with AAC can be performed with high technical success and acceptable morbidity and mortality in high-risk patients. Unplanned AAC placement during TEVAR results in an elevated stroke risk, which may be related to the branch vessel coverage necessitating AAC placement. Acceptable midterm survival can be anticipated, but aorta-related reintervention is not uncommon, and diligent follow-up is needed.

Female sex independently predicts mortality after thoracic endovascular aortic repair for intact descending thoracic aortic aneurysms

OBJECTIVE

Whereas sex differences in the pathogenesis, presentation, and outcomes of repair for abdominal aortic aneurysms are well studied, less is known about sex differences after thoracic endovascular aortic repair (TEVAR). The goal of this study was to evaluate the association between sex and morbidity and mortality after TEVAR.

METHODS

A retrospective review of all TEVARs in the Society for Vascular Surgery Vascular Quality Initiative (VQI) registry from 2011 to 2015 was conducted, excluding those with dissection, trauma, and rupture. Statistical analysis was performed using the Fisher exact test and the Mann-Whitney U test for categorical and continuous variables. Multivariable logistic regression and Cox hazards modeling were used to account for differences in demographics, comorbidities, and aneurysm characteristics in 30-day mortality and long-term survival.

RESULTS

We identified 2574 patients (40% women) who underwent TEVAR. Women were older, were less likely to be white, and had smaller aortic diameters but larger aortic size indices (aortic diameter/body surface area). Women also had more chronic obstructive pulmonary disease but less coronary artery disease and fewer coronary interventions. Women were more likely to be symptomatic at presentation and subsequently to have a nonelective procedure. Women had higher estimated blood loss >500 mL (20% vs 17%; P = .04), were more likely to be transfused (29% vs 21%; P < .001), and more frequently underwent iliac access procedures (4.3% vs 2.1%; P < .01). Operative time and left subclavian intervention were similar. Postoperatively, women had increased median hospital (5 vs 4 days; P < .001) and intensive care unit (2.5 vs 2 days; P < .001) lengths of stay and were less likely to be discharged home (75% vs 86%; P < .001). Mortality was higher for women at 30 days (5.4% vs 3.3%; P < .01) and 1 year (9.8% vs 6.3%; P < .01). After adjusting for age, aortic size index, symptoms, and comorbidities, female sex remained independently predictive of 30-day mortality (odds ratio, 1.5; 95% confidence interval, 1.1-2.1, P < .01) and long-term mortality (hazard ratio, 1.3; 95% confidence interval, 1.03-1.6; P = .02).

CONCLUSIONS

Even after adjusting for differences in age and comorbidities, female patients have higher perioperative mortality and lower long-term survival after TEVAR. These findings, along with the rupture risk by sex, should be considered by clinicians in determining the timing of intervention.

aCHEdb: the database system for ESTHER, the alpha/beta fold family of proteins and the Cholinesterase gene server

Acetylcholinesterase belongs to a family of proteins, the alpha/beta hydrolase fold family, whose constituents evolutionarily diverged from a common ancestor and share a similar structure of a central beta sheet surrounded by alpha helices. These proteins fulfil a wide range of physiological functions (hydrolases, adhesion molecules, hormone precursors) [Krejci,E., Duval,N., Chatonnet,A., Vincens,P. and Massoulié,J. (1991) Proc. Natl. Acad. Sci. USA , 88, 6647-6651]. ESTHER (for esterases, alpha/beta hydrolase enzymes and relatives) is a database aimed at collecting in one information system, sequence data together with biological annotations and experimental biochemical results related to the structure-function analysis of the enzymes of the family. The major upgrade of the database comes from the use of a new database management system: aCHEdb which uses the ACeDB program designed by Richard Durbin and Jean Thierry-Mieg. It can be found at http://www.ensam.inra.fr/cholinesterase

The evolution of MHC diversity by segmental duplication and transposition of retroelements

Sequence analysis of a 237 kb genomic fragment from the central region of the MHC has revealed that the HLA-B and HLA-C genes are contained within duplicated segments peri-B (53 kb) and peri-C (48 kb), respectively, and separated by an intervening sequence (IF) of 30 kb. The peri-B and peri-C segments share at least 90% sequence homology except when interrupted by insertions/deletions including Alu, L1, an endogenous retrovirus, and pseudogenes. The sequences of peri-B, IF, and peri-C were searched for the presence of Alu elements to use as markers of evolution, chromosomal rearrangements, and polymorphism. Of 29 Alu elements, 14 were identified in peri-B, 11 in peri-C, and 4 in IF. The Alu elements in peri-B and peri-C clustered phylogenetically into two clades which were classified as "preduplication" and "postduplication" clades. Four Alu J elements that are shared by peri-B and peri-C and are flanked by homologous sequences in their paralogous locations, respectively, clustered into a "preduplication" clade. By contrast, the majority of Alu elements, which are unique to either peri-B or peri-C, clustered into a postduplication clade together with the Alu consensus subfamily members ranging from platyrrhine-specific (Spqxcg) to catarrhine-specific Alu sequences (Y). The insertion of platyrrhine-specific Alu elements in postduplication locations of peri-B and peri-C implies that these two segments are the products of a duplication which occurred in primates prior to the divergence of the New World primate from the human lineage (35-44 mya). Examination of the paralogous Alu integration sites revealed that 9 of 14 postduplication Alu sequences have produced microsatellites of different length and sequence within the Alu 3'-poly A tail. The present analysis supports the hypothesis that HLA-B and HLA-C genes are products of an extended segmental duplication between 44 and 81 million years ago (mya), and that subsequent diversification of both genomic segments occurred because of the mobility and mutation of retroelements such as Alu repeats.

Psychological disturbances and an exaggerated response to pain in patients with whiplash injury

Psychological state, response to pain and style of interpreting everyday experiences were measured in 32 patients who had suffered a whiplash injury 1-84 months before the study. For comparison, measures were also obtained in 15 general practice attenders. Ratings of depression and anxiety were greater in patients than in controls, and patients reported more cold-induced pain during a cold pressor test. Within the patient sample, anxious subjects gave the highest ratings of cold-induced pain. Those with the longest history of pain gave the highest ratings of whiplash injury pain, and were most depressed. Most of these patients were involved in litigation. The findings demonstrate that, like most patients with chronic pain, whiplash injury sufferers are anxious and depressed. Their psychological distress could be aggravated by litigation. Behavioural assessment and treatment of chronic pain syndromes such as whiplash injury could benefit from early evaluation of the patient's psychological state, and response to standard painful stimuli.