Did Residents Stop Operating During COVID? Impact of COVID-19 Across VA Teaching Hospitals on Surgical Resident Education

BACKGROUND

During the COVID-19 pandemic, elective cases across the nation were suspended, leading to major decreases in operative volume for surgical trainees. Surgical resident operative autonomy has been declining over time, so we sought to explore the effect COVID-19 had on resident autonomy within VA teaching hospitals.

METHODS

A retrospective analysis of surgical cases across specialties was performed using the VA Surgical Quality Improvement Program database from September 2019 to September 2021 at VA teaching hospitals. Supervision codes are recorded prospectively: attending surgeon performs the operation (AP), resident completes majority of the case with the attending scrubbed (AR), and resident is primary surgeon without attending scrubbed (RP).

RESULTS

20,457 cases pre-COVID decreased to 11,035 during peak-COVID (P < .001). Overall, RP cases increased from 6.5% to 7.6% during the peak (P < .001) and trended back downwards during the recovery periods. AP decreased initially (29.9%-27.7%, P < .001), but regressed back to pre-pandemic numbers. In general surgery RP cases, urgent cases such as laparoscopic cholecystectomies increased from 18.8% to 27.5%, while elective repairs decreased during the peak. Similar changes were noted across specialties.

DISCUSSION

Operative cases dropped by half from pre- to peak- COVID and remained 20% below pre-pandemic volume the following year. Interestingly, RP rates increased for several specialties during the peak of the pandemic, which may have resulted from a relative higher ratio of resident personnel:case volume and shift in case distribution from elective to urgent. The increase in RP rate has begun to regress to pre-COVID levels which need to be readdressed.

Why Not This Case? Differences Between Resident and Attending Operative Cases at Teaching Hospitals

INTRODUCTION

Previous studies have focused on outcomes pertaining to resident operative autonomy, but there has been little academic work examining the types of patients and cases where autonomy is afforded. We sought to describe the differences between surgical patient populations in teaching cases where residents are and are not afforded autonomy.

METHODS

We examined all general and vascular operations at Veterans Affairs teaching hospitals from 2004 to 2019 using Veterans Affairs Surgical Quality Improvement Program. Level of resident supervision is prospectively recorded by the operating room nurse at the time of surgery: attending primary (AP): the attending performs the case with or without a resident; attending resident (AR): the resident performs the case with the attending scrubbed; resident primary (RP): resident operating with supervising attending not scrubbed. Resident (R) cases refer to AR + RP. Patient demographics, comorbidities, level of supervision, and top cases within each group were evaluated.

RESULTS

A total of 618,578 cases were analyzed; 154,217 (24.9%) were AP, 425,933 (68.9%) AR, and 38,428 (6.2%) RP. Using work relative value unit as a surrogate for complexity, RP was the least complex compared to AP and AR (10.4/14.4/14.8, P < 0.001). RP also had a lower proportion of American Society of Anesthesiologists 3 and 4 + 5 patients (P < 0.001), were younger (P < 0.001), and generally had lower comorbidities. The most common RP cases made up a higher proportion of all RP cases than they did for AP/AR and demonstrated several core competencies (hernia, cholecystectomy, appendectomy, amputation). R cases, however, were generally sicker than AP cases.

CONCLUSIONS

In the small proportion of cases where residents were afforded autonomy, we found they were more focused on the core general surgery cases on lower risk patients. This selection bias likely demonstrates appropriate attending judgment in affording autonomy. However, this cohort consisted of many "sicker" patients and those factors alone should not disqualify resident involvement.

Locally Advanced Gastric Cancer Management: A Cost-Effectiveness Analysis

Across the nation, patients with locally advanced gastric cancer (LAGC) are managed with modalities including upfront surgery (US) and perioperative chemotherapy (PCT). Preoperative therapies have demonstrated survival benefits over US and thus long-term outcomes are expected to vary between the options. However, as these 2 modalities continue to be regularly employed, we sought to perform a decision analysis comparing the costs and quality-of-life associated with the treatment of patients with LAGC to identify the most cost-effective option. We designed a decision tree model to investigate the survival and costs associated with the most commonly utilized management modalities for LAGC in the United States: US and PCT. The tree described costs and treatment strategies over a 6-month time horizon. Costs were derived from 2022 Medicare reimbursement rates using the third-party payer perspective for physicians and hospitals. Effectiveness was represented using quality-adjusted life-years (QALYs). One-way, two-way, and probabilistic sensitivity analyses were utilized to test the robustness of our findings. PCT was the most cost-effective treatment modality for patients with LAGC over US with a cost of $40,792.16 yielding 3.11 QALYs. US has a cost of $55,575.57 while yielding 3.15 QALYs; the incremental cost-effectiveness ratio (ICER) was $369,585.25. One-way and two-way sensitivity analyses favored PCT in all variations of variables across their standard deviations. Across 100,000 Monte Carlo simulations, 100% of trials favored PCT. In our model simulating patients with LAGC, the most cost-effective treatment strategy was PCT. While US demonstrated improved QALYs over PCT, the associated cost was too great to justify its use.

Declining Surgical Resident Operative Autonomy-All Trainees Are Not Created Equal

INTRODUCTION

We have previously shown that resident autonomy has decreased over time overall for all surgery residents. The purpose of this study is to examine changes in operative autonomy in general surgery residency within each postgraduate year (PGY) level.

MATERIALS AND METHODS

This is a retrospective analysis of the Veterans Association Surgical Quality Improvement Program database from July 1, 2004 to September 30, 2019. All general surgery, vascular surgery, and thoracic surgery procedures were analyzed and categorized by level of resident supervision as attending primary, attending operating with resident, or resident primary without attending scrubbed. Procedure work portion of relative value unit was used to capture procedure complexity. Changes in resident autonomy over time, procedure complexity, and outcomes were compared among PGY levels 1 to 5.

RESULTS

A total of 385,482 cases were analyzed. At each PGY level from 2014 to 2018, the relative decrease in resident primary cases ranged from -37.3% (PGY 4) to -75.5% (PGY 3). Mean work portion of relative value unit saw steady increase with PGY level (8.4 ± 3.5 in PGY 1 to 10.8 ± 5.7 in PGY 5, P < 0.001) and did not show a trend over time.

CONCLUSIONS

Surgical resident operative autonomy has markedly decreased over time across all PGY levels. This effect is most profound at the PGY 3 level, while more senior residents are affected to a lesser degree. Case complexity show PGY level-appropriate increase in resident autonomous cases. Decrease in resident autonomy over time is not associated with changes in case complexity.

Anterior Abdominal Varicosities Due to Unilateral Common and External Iliac Vein Occlusion Five Decades Post-Injury

Abdominopelvic varicosities are a rare occurrence after traumatic venous injuries. Several disorders exist that present with abdominopelvic varicosities such as May-Thurner syndrome, pelvic congestion syndrome, and nutcracker syndrome; however, it has rarely been described after trauma.¹ We present a case in 70-year-old male, who in 1974 sustained a penetrating injury from fragments secondary to mortar explosion, requiring exploratory laparotomy. He presented to the hospital with abdominopelvic varicosities that began 20 years after the incident and was asymptomatic at initial presentation. While there is a known case report of congenital absence of a common iliac vein in a young, healthy, athletic man who developed abdominopelvic varicosities, this is the first case report, to our knowledge, of evolution of a traumatic injury of this nature over a lifetime. Pathophysiology, diagnostics, risks of ligation, and management of chronic abdominopelvic varicosities in this patient are discussed.

Declining Resident Surgical Autonomy and Improving Surgical Outcomes: Correlation Does Not Equal Causality

OBJECTIVE

The volume of cases that residents perform independently have decreased leaving graduating chief residents less prepared for independent practice. Outcomes are not worse when residents are given autonomy with appropriate supervision, however it is unknown if outcomes are worsening with decreasing operative autonomy experience. We hypothesize that resident autonomous cases parallel the improving outcomes in surgical care over time, however, are less complex and on lower acuity patients.

DESIGN

Retrospective study utilizing the Veterans Affairs Surgical Quality Improvement Program (VASQIP) database.

SETTING

Operative cases performed on teaching services within the VASQIP database from July 1, 2004 to September 30, 2019, were included.

PARTICIPANTS

All adult patients who underwent a surgical procedure from July 1, 2004, to September 30, 2019, at a VA hospital on a service that included residents were initially included. After inclusions and exclusions, there were 1,346,461 cases. Cases were divided into 3 sequential 5 year eras (ERA 1: 2004-2008 n = 415,614, ERA 2: 2009-2013 n = 478,528, and ERA 3: 2014-2019 n = 452,319). The main exposure of interest was level of resident supervision, coded at the time of procedure as: attending primary surgeon (AP); attending and resident (AR), or resident primary with the attending supervising but not scrubbed (RP). We compared 30 day all-cause mortality, composite morbidity, work relative value unit (wRVU), hospital length of stay, and operative time between each ERA for RP cases, as well as within each ERA for RP cases compared to AR and AP cases.

RESULTS

There was a progressive decline in the rate of RP cases in each successive ERA (ERA 1: 58,249 (14.0%) vs ERA 2: 47,891 (10.0%) vs ERA 3: 35,352 (7.8%), p < 0.001). For RP cases, patients were progressively getting older (60 yrs [53-71] vs 63 yrs [54-69] vs 66 yrs [57-72], p < 0.001) and sicker (ASA 3 58.7% vs 62.5% vs 66.2% and ASA 4/5 8.4% vs 9.6% vs10.0%, p < 0.001). Odds of mortality decreased in each ERA compared to the previous (aOR 0.71 [0.62-0.80] ERA 2 vs ERA 1 and 0.82 [0.70-0.97] ERA 3 vs ERA 2) as did morbidity (0.77 [0.73-0.82] ERA 2 vs ERA 1 and 0.72 [0.68-0.77] ERA 3 vs ERA 2). Operative and length of stay also decreased while wRVU stayed unchanged. When comparing RP cases to AP and AR within each ERA, RP cases tended to be on younger and healthier patients with a lower wRVU, particularly compared to AR cases. Mortality and morbidity were no different or better in RP compared to AR and AP.

CONCLUSIONS

Despite resident autonomy decreasing, outcomes in cases where they are afforded autonomy are improving over time. This despite RP cases being on sicker and older patients and performing roughly the same complexity of cases. They also continue to perform no worse than cases with higher levels of supervision. Efforts to increase surgical resident operative autonomy are still needed to improve readiness for independent practice.

Declining Surgical Resident Operative Autonomy in Acute Care Surgical Cases

INTRODUCTION

Surgical resident operative autonomy has decreased markedly over time, reducing resident readiness for independent practice. We sought to examine operative resident autonomy for emergency acute care surgery (ACS) compared to elective cases and associated patient outcomes at veterans affairs hospitals.

METHODS

The Veterans Affairs Surgical Quality Improvement Program database was queried for ACS cases (emergency general, vascular, and thoracic) at veterans affairs hospitals from 2004 to 2019. Cases are coded prospectively for the level of supervision: attending primary surgeon (AP); attending scrubbed with resident surgeon (AR); resident primary (RP), attending not scrubbed. Baseline demographics, operative variables, and outcomes were compared.

RESULTS

A total of 61,275 ACS cases and 605,146 elective cases were performed during the study period. The ACS had a higher proportion of RP cases (7.2% versus 5.7%, P < 0.001). The proportion of ACS RP cases decreased from 9.9% to 4.1% (58.6%); elective RP cases decreased from 8.9% to 2.9% (67.4%). The most common ACS RP surgeries were appendectomy, amputations, and cholecystectomy. RP cases had lower American Society of Anesthesia class and lower median work relative value units than AP and AR. There was no difference between mortality rates of RP compared to AP (adjusted odds ratio [OR] 0.94 [0.80-1.09] or AR 0.94 [0.81-1.08]). While there was no difference in complications between the RP and AP (OR 1.01 [0.92-1.12]), there were significantly more complications in AR compared to RP (OR 1.20 [1.10-1.31]).

CONCLUSIONS

More autonomy is granted for ACS cases compared to elective cases. While both decreased over time, the decrease is less for ACS cases. Resident autonomy does not negatively impact outcomes, even in emergent cases.

Patient inequities in affording surgical resident operative autonomy at Veterans Affairs teaching hospitals, does it extend to female patients?

BACKGROUND

Examining surgical resident operative autonomy within the Veterans Affairs (VA) System, we previously showed residents were afforded autonomy more frequently on Black patients. We hypothesized that, compared to males, female surgical patients receive less attending involvement and more resident autonomy during surgery.

METHODS

Retrospective review of all general/vascular surgeries performed at teaching VA hospitals from 2004 to 2019. Operative procedures are coded at the time of surgery as attending primary surgeon (AP), attending with resident (AR), or resident primary surgeon--attending not scrubbed (RP). The primary outcome was the difference in supervision rates between patient sexes.

RESULTS

618,578 operations were examined-24.9% AP, 68.9% AR, and 6.2% RP. Overall, 5.9% of cases were performed on women. The rate of RP cases was higher in males compared to females (6.3% vs 5.3%, p < 0.001).

CONCLUSION

Female veterans are less likely to have residents operate on them autonomously. Reasons for this require further characterization.

General Surgery Resident Complement and Operative Autonomy - Size Matters

OBJECTIVE

Operative autonomy has progressively decreased for surgery residents. This study investigates the effect of general surgery resident complement size at Veterans Affairs (VA) hospitals on operative autonomy for the residents. We hypothesize that smaller complements of residents would result in fewer opportunities for operative autonomy.

DESIGN

Retrospective analysis of the Veterans Affairs Surgical Quality Improvement Program (VASQIP) database.

SETTING

Operative cases within the VASQIP database from July 1, 2004 to September 30, 2019 were analyzed.

PARTICIPANTS

All general surgery procedures performed at teaching VA hospitals from January 2004 to September 2019 were included. The level of resident operative autonomy is defined as follows: attending primary surgeon with or without a resident (AP), resident primary surgeon with attending scrubbed (AR), and resident primary without attending scrubbed (RP). Resident complement is based on funded resident positions at each VA hospital during the academic year 2017-2018 and stratified into 3 groups: small (≤4), medium (>4-<7), and large (≥7). The primary outcome was the proportion of operative autonomy for each resident complement group. Secondary outcomes were level of autonomy over time, and mortality and morbidity for RP procedures. Categorical data were compared with Chi-squared test.

RESULTS

Four hundred sixty-one thousand seven hundred thirty-four procedures across 92 VA hospitals with general surgery residents were included in the analysis. There were 126,062 cases performed at 29 small resident complement hospitals, 135,539 at 28 medium resident complement hospitals, and 200,133 at 35 large resident complement hospitals. The percentage of RP procedures was higher with increasing resident complement (2.1% vs 6.8% vs 9.9%, p < 0.001). RP procedures have decreased over time in all groups, but the relative decrease was less pronounced as resident complement increased (79.5% vs 73.3% vs 64.7%, p < 0.001). There was no significant difference in adjusted 30-day all-cause mortality between groups.

CONCLUSIONS

Increased resident complement at VA hospitals is associated with increased resident autonomy in resident primary procedures. Resident autonomy has decreased over time regardless of complement size, but it is less dramatic at sites with more residents. Increasing resident complement at a site may improve operative autonomy, leading to an improved educational experience for surgical residents.

Increasing volume but declining resident autonomy in laparoscopic inguinal hernia repair: an inverse relationship

INTRODUCTION

With improved technology and technique, laparoscopic inguinal hernia repair (LIHR) has become a valid option for repairing both initial and recurrent inguinal hernia. Surgical residents must learn both techniques to prepare for future practice. We examined resident operative autonomy between LIHR and open inguinal hernia repair (OIHR) across the Veterans Affairs (VA) system.

METHODS

Utilizing the VA Surgical Quality Improvement Program database, we examined inguinal hernia repairs based on the principal procedure code at all teaching VA hospitals from July 2004 to September 2019. All VA cases are coded for level of supervision at the time of surgery: attending primary surgeon (AP); attending scrubbed but resident is a primary surgeon (AR), and resident primary with attending supervising but not scrubbed (RP). Primary outcomes were the proportion of LIHR versus OIHR and resident autonomy over time.

RESULTS

A total of 127,497 hernia repair cases were examined (106,892 OIHR and 20,605 LIHR). There was a higher proportion of RP (8.7% vs 2.2%) and lower proportion of AP (23.9% vs 28.4%) within OIHR compared to LIHR (p < 0.001). The overall proportion of LIHR repairs increased from 9 to 28% (p < 0.001). RP cases decreased for LIHR from 9 to 1% and for OIHR from 17 to 4%, while AP cases increased for LIHR from 16 to 42% and for OIHR from 18 to 30% (all p < 0.001). For RP cases, mortality (0 vs 0.2%, p > 0.99) and complication rates (1.1% vs. 1.7%, p = 0.35) were no different.

CONCLUSIONS

LIHR at VA hospitals has tripled over the past 15 years, now compromising nearly one-third of all inguinal hernia repairs; the majority are initial hernias. Despite this increase, resident autonomy in LIHR cases declined alarmingly. The results demonstrate an urgent need to integrate enhanced minimally invasive training into a general surgery curriculum to prepare residents for future independent practice.

Sigmoid Colectomy for Sigmoid Volvulus Through a Limited Left Lower Quadrant Transverse Laparotomy Incision Without Laparoscopy

Sigmoid volvulus (SV) is a relatively rare cause of large bowel obstruction encountered by general surgeons in the United States. It predominantly affects the elderly, infirm, and institutionalized. Surgery after endoscopic reduction is the mainstay of treatment. Given the frail nature of the population requiring partial colectomy for SV, formal laparotomy and laparoscopic sigmoid colectomies come with significant risks. Much of the risk related to a minimally invasive, laparoscopic approach is due to the physiologic impacts of pneumoperitoneum. This series demonstrates a technique whereby a complete sigmoid resection with or without anastomosis can be achieved via a single, small incision equivalent to a laparoscopic extraction port. This technique took advantage of the redundancy in the sigmoid colon characteristic of SV. All patients tolerated their procedures well and had rapid return to their baseline function.

Cost-effectiveness analysis of infected necrotizing pancreatitis management in an academic setting

BACKGROUND AND AIMS

Traditional management for infected necrotizing pancreatitis (INP) often utilizes open necrosectomy, which carries high morbidity and complication rates. Thus, minimally invasive strategies have gained favor, specifically step-up approaches utilizing endoscopic or minimally-invasive surgery (MIS); however, the ideal management modality for INP has not been identified.

METHODS

A decision tree model was designed to analyze costs and survival associated with open necrosectomy, endoscopic step-up, and MIS step-up protocols for management of INP after 4 weeks of necrosis development with adequate retroperitoneal access. Costs were based on a third-party payer perspective using Medicare reimbursement rates. The model's effectiveness was represented by quality-adjusted life-years (QALYs). Sensitivity analyses were performed to validate results.

RESULTS

Endoscopic step-up was the dominant economic strategy with 7.92 QALYs for $90,864.09. Surgical step-up resulted in a decrease of 0.09 QALYs and a cost increase of $10,067.89 while open necrosectomy resulted in a decrease of 0.4 QALYs and an increased cost of $18,407.52 over endoscopic step-up. In 100,000 random-sampling simulations, 65.5% of simulations favored endoscopic step-up. MIS step-up was favored when MIS acute mortality rates fell and when MIS drainage success rates rose.

CONCLUSIONS

In our simulated patients with INP, the most cost-effective management strategy is endoscopic step-up. Cost-effectiveness varies with changes in acute mortality and drainage success, which will depend on local expertise.

Association Between Operative Autonomy of Surgical Residents and Patient Outcomes

IMPORTANCE

Resident operative autonomy has been steadily decreasing. Whether this reduction in autonomy has been associated with changes in patient outcomes is unclear.

OBJECTIVE

To assess whether surgical procedures performed by residents without an attending surgeon scrubbed are associated with differences in patient outcomes compared with procedures performed by attending surgeons alone or by residents with the assistance of attending surgeons.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective propensity score-matched cohort study analyzed 30-day outcomes among patients who received operations at US Veterans Affairs (VA) medical centers and were recorded within the VA Surgical Quality Improvement Program (VASQIP) database from July 1, 2004, to September 30, 2019. Among 1 797 056 operations recorded in the VASQIP during that period, 1 319 020 were eligible for inclusion. Operations performed by a surgical resident without an attending surgeon scrubbed (resident primary) were propensity score matched on a 1:1 ratio (based on year of procedure and patient age, race, sex, American Society of Anesthesiologists physical status classification, functional status, emergency status, inpatient status, presence of multiple comorbidities, and Current Procedural Terminology code) to operations performed by an attending surgeon only (surgeon primary) and operations performed by a resident with assistance from an attending surgeon (resident plus surgeon).

EXPOSURES

Level of resident involvement.

MAIN OUTCOMES AND MEASURES

Thirty-day adjusted all-cause mortality.

RESULTS

Among 1 319 020 surgical procedures included, 138 750 were performed by residents only, 308 724 were performed by surgeons only, and 871 546 were performed by residents and surgeons. For the 1 319 020 total cases, patients' mean (SD) age was 61.6 (12.9) years; 1 223 051 patients (92.7%) were male; and 212 315 (16.1%) were Black or African American, 63 817 (4.9%) were Hispanic, 830 704 (63.0%) were White, and 212 814 (16.1%) were of other or unknown race and ethnicity. Propensity score matching produced 101 130 pairs of resident-primary and surgeon-primary procedures and 137 749 pairs of resident-primary and resident plus surgeon procedures. Patient all-cause mortality and morbidity were no different among those who received surgeon-primary procedures (mortality: odds ratio [OR], 1.03 [95% CI, 0.95-1.12]; morbidity: OR, 1.01 [95% CI, 0.97-1.05]) vs resident plus surgeon procedures (mortality: OR, 1.03 [95% CI, 0.97-1.11]; all-cause morbidity: OR, 0.97 [95% CI, 0.95-1.00]). Resident-primary procedures had longer operative times than surgeon-primary procedures (median, 80 minutes [IQR, 50-123 minutes] vs 70 minutes [IQR, 41-114 minutes], respectively; P < .001) but shorter operative times than resident plus surgeon procedures (median, 71 minutes [IQR, 43-113 minutes] vs 73 minutes [IQR, 45-115 minutes]; P < .001). Hospital length of stay was unchanged among resident-primary vs surgeon-primary procedures (median, 4 days [IQR, 2-10 days] vs 4 days [IQR, 2-9 days]; P = .08) and statistically significantly shorter than resident plus surgeon procedures (median, 4 days [IQR, 1-9 days] vs 4 days [IQR, 2-10 days]; P < .001).

CONCLUSIONS AND RELEVANCE

In this cohort study, surgical procedures performed by residents alone were not associated with any changes in all-cause mortality or composite morbidity compared with those performed by attending surgeons alone or by residents with the assistance of attending surgeons. Given these findings and the importance of operative autonomy to prepare surgical residents for independent practice, efforts to increase autonomy are both safe and needed.

General Surgical Resident Operative Autonomy vs Patient Outcomes: Are we Compromising Training without Net Benefit to Hospitals or Patients?

OBJECTIVE

Resident operative autonomy has been steadily declining. The reasons are multifactorial and include concerns related to patient safety and operating room efficiency. Simultaneously, faculty have expressed that residents are less prepared for independent practice. We sought to understand the effect of decreasing resident autonomy on patient outcomes and operative duration.

DESIGN

Retrospective study utilizing the Veterans Affairs Surgical Quality Improvement Program (VASQIP) database.

SETTING

Operative cases within the VASQIP database from July 1, 2004-September 30, 2019 were analyzed.

PARTICIPANTS

All adult patients who underwent a surgical procedure from July 1, 2004 to September 30, 2019 were analyzed. The subpopulation of patients that underwent a surgical procedure in General Surgery or Peripheral Vascular Surgery were identified based on the code of the specialty surgeon. Within these subgroups, the most frequent cases by current procedural terminology (CPT) code were selected for study inclusion. The principle CPT code of all cases was further coded by level of supervision: attending primary surgeon (AP); attending and resident (AR), or resident primary with the attending supervising but not scrubbed (RP). Baseline demographics, operative variables, and outcomes were compared between groups.

RESULTS

The VASQIP database included 698,391 total general/vascular surgery cases. 38,483 (6%) of them were RP cases. Analysis revealed that the top 5 RP cases account for 73% of total RP volume-these include: 1) Hernias (55% total; 33% open inguinal, 13% umbilical, 5% open ventral/incisional, and 4% laparoscopic) 2) cholecystectomy (18%), 3) Amputations (17% total; 10% above knee, 7% below knee), 4) Appendectomy (7%) and 5) Open colectomy (3%). The percentage of cases at teaching hospitals that were RP cases significantly decreased from 15% in 2004 to 5% in 2019 (p < 0.001). RP cases were generally sicker as demonstrated by higher ASA classifications and more likely to be emergent cases. Operative times were also increased with resident involvement, but RP cases were faster than AR cases on average. After adjusting for baseline demographics, case type, and year of procedure, mortality was no different between groups. Complications were higher in the AR group but not in the RP group.

CONCLUSIONS

The rate of resident autonomy in routine general surgery cases has decreased by two-thirds over the 15-year study period. Cases performed by residents without an attending surgeon scrubbed were performed faster than cases performed by a resident and attending together and there was no increase in patient morbidity or mortality when residents performed cases independently. The erosion of resident autonomy is not justified based upon operative time or patient outcomes. Efforts to increase surgical resident operative autonomy are needed.

The Impact of Chronic Liver Disease on Postoperative Outcomes and Resource Utilization

BACKGROUND

Multiple studies have shown high rates of postoperative morbidity and mortality in individuals with chronic liver disease (CLD). However, analyses from comparisons with individuals without CLD are not available. Such analyses might provide opportunities to improve outcomes.

METHODS

Data from The National Surgical Quality Improvement Program (NSQIP) from 2008 to 2011 were analyzed comparing CLD patients undergoing non-liver surgery propensity matched to those without CLD. Patients with CLD were stratified by Model of End Stage Liver Disease (MELD) scores <15 and ≥15. Primary outcome was all cause mortality, and secondary outcomes were composite and individual morbidity, hospital length of stay, readmission, reoperation, and discharge destination. Odds ratios (OR) were calculated, and length of hospital stay was estimated using Poisson regression.

RESULTS

There were 6,209 patients with CLD (4,013 with low MELD, 2,196 with high MELD) matched to 18,627 patients without. Patients with CLD had 1.8- and 3.3-times higher odds of mortality (95% CI 1.6-2.1 for Low MELD (10.6%), 2.9-3.8 for high MELD (35.2%), and 1.8- and 2.2-times higher odds of any morbidity (1.6-1.9 and 1.9-2.4). Complications specific to CLD were increased based on MELD specifically coma (OR 1.6, 0.9-2.9 for Low MELD, 2.2, 1.5-3.2 for High MELD), renal failure (OR 1.4, 1.1-1.8 and 2.4, 2.0-2.9), and bleeding (OR 1.7, 1.5-1.9 and 2.0, 1.8-2.3). They also had a 20% and 80% longer length of stay, 2.2- and 3.4-times higher odds of being discharged somewhere other than home, 1.7- and 1.6-times higher odds of readmission, and 1.5- and 1.6-times higher odds of reoperation.

CONCLUSION

Patients with CLD have significantly higher odds of mortality and morbidity, which is increased with a higher MELD. Interventions that decrease those morbidities are needed and have the potential to decrease mortality and resource utilization.

Cost-effectiveness analysis of gastric cancer management using perioperative chemotherapy versus adjuvant chemoradiation therapy

e16079

Background: The most commonly used treatment options for gastric cancer include complete resection with adequate margins with either perioperative chemotherapy (PCT) or adjuvant chemoradiotherapy (CRT). While both treatment strategies have shown superiority over surgical resection alone, it is not clear which treatment strategy is more optimal. Methods: Our decision tree model was built to analyze the survival and costs associated with the two major management methods: perioperative chemotherapy and adjuvant chemoradiation therapy. Costs were obtained from Medicare reimbursement rates using a third-party payer perspective. Our model’s effectiveness was represented using quality-adjusted life years (QALYs). Our analysis tested the robustness of our conclusions by utilizing one-way, two-way, and probabilistic sensitivity analyses. Results: PCT was the preferred treatment strategy for diagnosed gastric cancer over CRT, with a cost of $54,326.10 and 4.08 QALYs. CRT was the costliest economic strategy with a cost of $77,987.52 and 4.28 QALYs and an ICER of 115,907.48. We set a threshold of $100,000 per QALYs gained which CRT surpassed making PCT the preferred treatment modality. Over 100,000 simulations, 51.4% of simulations favored PCT. CRT became favored when CRT non-curative procedure rates rose 3% higher than PCT non-curative procedure rates and when PCT complication rates rose 15% higher than CRT complication rates. Conclusions: In our simulated patients with diagnosed gastric cancer, the most cost-effective treatment strategy was PCT. We see cost-effectiveness alternating to favor CRT with changes in non-curative procedure rates and adjuvant therapy complication rates.[Table: see text]

Relationship of Imported Fire Ant (Hymenoptera: Formicidae) Integument Coloration to Cuticular Hydrocarbon and Venom Alkaloid Profiles

Red imported fire ant (Solenopsis invicta Buren; RIFA) and black imported fire ant (Solenopsis richteri Forel (Hymenoptera: Formicidae); BIFA) are considered distinct species with introgression via a reproductively functional hybrid (HIFA). The RIFA and BIFA common names are based on relative coloration. Due to human color perception variation, using color to identify RIFA, BIFA or HIFA is challenging. Fire ant identification traditionally involves molecular or chemical techniques, but a colorimetric test could allow rapid and low-cost identification. In this study, ant integument coloration was measured by spectrophotometer, and color attributes were compared to a combined gas chromatography (GC) index derived from cuticular hydrocarbon and venom alkaloid indices. Significant Pearson Correlation coefficients were found for colony GC index versus color attributes red to green (a*), blue to yellow (b*), chroma (C*), and hue (h*), but not lightness (L*). The RIFA colonies were distinct from BIFA for four of five color attributes and plots of the a*b* and C*h* horizontal axis of the L*a*b* and L*C*h* color spaces. Color attributes for HIFA indices were not distinct from BIFA and RIFA parental species, but HIFA a*b* and C*h* plots were distinct from RIFA and a*b* plots from BIFA. Color attributes a*, b*, and C* increased and h* decreased with GC index in a sinusoidal pattern. In conclusion, most RIFA and BIFA color attributes were distinct and a*b* and C*h* color axes plots had potential to distinguish HIFA from parental species, but coloration of HIFA indices was variable and complicated identifications among HIFA phenotypes, RIFA and BIFA.

The Association of Chronic Opioid Use with Resource Utilization and Outcomes after Emergency General Surgery

INTRODUCTION

Chronic opioid use is prevalent among patients undergoing emergent surgery. We sought to understand it on the outcomes of the most common emergency surgery procedures, Appendectomy and Cholecystectomy.

METHODS

We used the National Inpatient Sample to identify chronic opioid use in emergency appendectomies (n = 953) and cholecystectomies (n = 2826) from 2005 to 2014. Primary outcome was length of stay (LOS), and secondary outcomes included total charges and mortality. LOS was analyzed with multivariate Poisson regression, total charges with multivariate linear regression.

RESULTS

For Appendectomy, the opioid abuse group was younger, had similar gender and racial demographics, had more Medicaid and private insurance and less self-pay, and had no clinically significant differences in comorbidities. Those with chronic opioid use had a 24% increased LOS (20-29%, p < .001) and $5532(±$881, p < .001) higher hospital charges. Mortality was very rare and not different (0.2% vs 0.6%, aOR 0.54 [0.11-2.58], p = .44). For Cholecystectomy, the opioid abuse group was similar in age and gender, had slightly more white individuals, had a slightly different payor mix including higher rate of private insurance, and had no clinically significant differences in comorbidities. Patients with preoperative chronic opioid abuse showed a 14% increased LOS (12-16%, p < .001) and $5352 (± $1065, p < .001) higher hospital charges, but no significant increase in mortality (0.7% vs 0.6%, aOR 1.58 [0.77-3.25], p = .22).

CONCLUSION

Patients with chronic opioid abuse did not have increased mortality following EGS but had increased resource utilization and LOS. These findings may help explore the impact of opioid abuse on hospital and societal cost.

Mechanisms of picosecond laser-induced damage in common multilayer dielectric gratings

The modifications of multilayer dielectric (MLD) gratings arising from laser-induced damage using 0.6-ps and 10-ps laser pulses at 1053 nm are investigated to better understand the damage-initiation mechanisms. Upon damage initiation, sections of the affected grating pillars are removed, thereby erasing the signature of the underlying mechanisms of laser damage. To address this issue, we performed paired studies using macroscopic grating-like features that are 5 mm in width to reveal the laser-damage morphology of the different grating sections: pillar side wall, sole, and pillar top. The results suggest that, similarly to MLD coatings, there are two damage-initiation mechanisms corresponding to the different pulse durations.

Impact of insurance status on overall survival after cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS-HIPEC)

Objectives

The impact of insurance status on oncological outcome in patients undergoing cytoreduction and hyperthermic intraperitoneal chemotherapy (CRS-HIPEC) is poorly understood.

Methods

Retrospective study on 31 patients having undergone 36 CRS-HIPEC at a single institution (safety-net hospital) between 2012 and 2018. Patients were categorized as insured or underinsured. Demographics and perioperative events were compared. Primary outcome was overall survival (OS).

Results

A total of 20 patients were underinsured and 11 were insured. There were less gynecologic malignancies in the underinsured (p=0.02). On univariate analysis, factors linked to poor survival included gastrointestinal (p=0.01) and gynecologic malignancies (p=0.046), treatment with neoadjuvant chemotherapy (p=0.03), CC1 (p=0.02), abdominal wall resection (p=0.01) and Clavien–Dindo 3-4 (p=0.01). Treatment with neoadjuvant chemotherapy and abdominal wall resections, but not insurance status, were independently associated with OS (p=0.01, p=0.02 respectively). However, at the end of follow-up, six patients were alive in the insured group vs. zero in the underinsured group.

Conclusions

In this small, exploratory study, there was no statistical difference in OS between insured and underinsured patients after CRS-HIPEC. However, long-term survivors were observed only in the insured group.

Stress compensation by deposition of a nonuniform corrective coating

Surface deformation by coating stress is compensated by prefiguring the substrate with a radially nonuniform layer of dense silica. Stresses in the compensation layer and reflector are modeled using finite element analysis to determine the optimal thickness profile, with the deposited coating reducing the surface deformation by 90%. This process is intended to allow implementation of both the compensation layer and the traditional multilayer coating in a single vacuum cycle.

Ellipsometric modeling of serially bi-deposited glancing-angle-deposition coatings

Ellipsometric modeling of serially bi-deposited glancing-angle-deposition (GLAD) coatings with a high degree of accuracy is imperative for multilayer coatings. High-precision dispersion curves are demonstrated for a wide variety of applications.

Large-aperture coatings for fusion-class laser systems

Optical coatings for fusion-class laser systems pose unique challenges, given the large substrate sizes, the high intensities incident on the coatings, and the system-focusing requirements, necessitating a well-controlled optical wavefront. Significant advancements have taken place in the past 30 years to achieve the coating capabilities necessary to build laser systems such as the National Ignition Facility, Laser Mégajoule, OMEGA EP, and OMEGA. This work summarizes the coating efforts and advancements to support such system construction and maintenance.

Glancing-angle-deposited silica films for ultraviolet wave plates

Birefringent silica films are formed by glancing-angle deposition to fabricate quarter- and half-wave plates at a wavelength of 351 nm. A multilayer design is implemented to achieve low-loss transmittance with a high 351-nm laser-induced damage threshold.

Influence of absorption-edge properties on subpicosecond intrinsic laser-damage threshold at 1053 nm in hafnia and silica monolayers

Owing to their relatively high resistance to laser-induced damage, hafnia and silica are commonly used in multilayered optical coatings in high-power laser facilities as high- and low-refractive-index materials, respectively. Here, we quantify the laser-induced-damage threshold (LIDT) at 1053 nm in the short-pulse regime of hafnia and silica monolayers deposited by different fabrication methods, including electron-beam evaporation, plasma ion-assisted deposition and ion-assisted deposition. The results demonstrate that nominally identical coatings fabricated by different deposition techniques and/or vendors can exhibit significantly different damage thresholds. A correlation of the LIDT performance of each material with its corresponding absorption edge is investigated. Our analysis indicates a weak correlation between intrinsic LIDT and the optical gap of each material (Tauc gap) but a much better correlation when considering the spectral characteristics in the Urbach tail spectral range. Spectrophotometry and photothermal absorption were used to provide evidence of the correlation between the strength of the red-shifted absorption tail and reduced LIDT at 1053 nm.

Worker Size, Geographical Distribution, and Introgressive Hybridization of Invasive Solenopsis invicta and Solenopsis richteri (Hymenoptera: Formicidae) in Tennessee

Worker size and geographical distribution of red imported fire ants (Solenopsis invicta Buren), black imported fire ants (Solenopsis richteri Forel), and their hybrid (S. invicta × S. richteri) (Hymenoptera: Formicidae) were evaluated from colonies sampled across Tennessee. The fire ant species and hybrid status were determined using cuticular hydrocarbon and venom alkaloid indices obtained from gas chromatography and mass spectrometry. Hybrids were the most common fire ant throughout Tennessee. With the exception of a few isolated S. invicta samples, only hybrids were found in east Tennessee, and hybrids predominated in middle Tennessee. In west Tennessee, mixed populations of S. richteri and hybrids were found. Hybrids were more common in west Tennessee than a survey performed a decade earlier. No statistical differences were detected in the average inter-colonial worker size of S. richteri and hybrids. Likewise, average worker size was not related to geographic location in Tennessee. The similarity in average worker size among hybrid colonies with a wide range of cuticular hydrocarbon and venom alkaloid values suggests introgression was not impacting ant size in colonies sampled throughout Tennessee.

Simulation of internal stress waves generated by laser-induced damage in multilayer dielectric gratings

Multilayer dielectric (MLD) gratings used in ultrahigh-intensity laser systems often exhibit a laser-induced damage performance below that of their constituent materials. Reduced performance may arise from fabrication- and/or design-related issues. Finite element models were developed to simulate stress waves in MLD grating structures generated by laser-induced damage events. These models specifically investigate the influence of geometric and material parameters on how stress waves can lead to degradation of material structural integrity that can have adverse effects on its optical performance under subsequent laser irradiation: closer impedance matching of the layer materials reduces maximum interface stresses by ~20% to 30%; increasing sole thickness from 50 nm to 500 nm reduces maximum interface stresses by ~50%.

Optical properties of oxygen vacancies in HfO2 thin films studied by absorption and luminescence spectroscopy

Hafnium oxide thin films with varying oxygen content were investigated with the goal of finding the optical signature of oxygen vacancies in the film structure. It was found that a reduction of oxygen content in the film leads to changes in both, structural and optical characteristics. Optical absorption spectroscopy, using nanoKelvin calorimetry, revealed an enhanced absorption in the near-ultraviolet (near-UV) and visible wavelength ranges for films with reduced oxygen content, which was attributed to mid-gap electronic states of oxygen vacancies. Absorption in the near-infrared was found to originate from structural defects other than oxygen vacancy. Luminescence generated by continuous-wave 355-nm laser excitation in e-beam films showed significant changes in the spectral profile with oxygen reduction and new band formation linked to oxygen vacancies. The luminescence from oxygen-vacancy states was found to have microsecond-scale lifetimes when compared with nanosecond-scale lifetimes of luminescence attributed to other structural film defects. Laser-damage testing using ultraviolet nanosecond and infrared femtosecond pulses showed a reduction of the damage threshold with increasing number of oxygen vacancies in hafnium oxide films.

Liver biopsy in assessment of extended criteria donors

The safety and liver utilization with prerecovery liver biopsy (PLB) in extended criteria liver donors are unclear. We conducted a retrospective cohort study in 1323 brain death donors (PLB = 496) from 3 organ procurement organizations (OPOs). Outcomes were complications, preempted liver recovery (PLR), and liver transplantation (LT). Additional analyses included liver-only and propensity score-matched multiorgan donor subgroups. PLB donors were older (57 versus 53 years; P < 0.001). Hepatitis C antibody positivity (14.3% versus 9.6%, P = 0.01) and liver-only donors (42.6% versus 17.5%; P < 0.001) were more prevalent. The PLB cohort had fewer complications (31.9% versus 42.3%; P < 0.001). In the PLB cohort, PLR was significantly higher (odds ratio [OR], 3.45; 95% confidence interval [CI], 2.42-4.92) and LT lower (OR, 0.69; 95% CI, 0.52-0.91). In liver-only and propensity score-matched multiorgan donor subgroups, PLR was significantly higher (OR, 1.76; 95% CI, 1.06-2.94 and OR, 2.29; 95% CI, 1.37-3.82, respectively) without a decrease in LT (OR, 0.71; 95% CI, 0.43-1.18 and OR, 0.91; 95% CI, 0.63-1.33, respectively) in PLB subgroups. In conclusion, in extended criteria liver donors, PLB is safe and decreases futile liver recovery without decreasing LT. Increased use of PLB, especially in liver-only donors, is likely to save costs to OPOs and transplant centers and improve efficiencies in organ allocation. Liver Transplantation 24 182-191 2018 AASLD.

Abdominal wall reconstruction after cytoreduction surgery-hyperthermic intraperitoneal chemotherapy

BACKGROUND

Cytoreduction surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) improve survival and decrease recurrence of peritoneal metastasis in a select population of patients. Abdominal wall resection is often needed to achieve complete CRS and the extent of abdominal wall resection may necessitate abdominal wall reconstruction (AWR). We sought to investigate if postoperative morbidity and mortality was increased in patients who underwent AWR with CRS-HIPEC (AWR group) compared to CRS-HIPEC without AWR (non-AWR group) and to identify if patient, tumor, and operative risk factors were associated with poor outcomes following AWR. We postulate that AWR is a safe and viable treatment option in appropriately selected patients with peritoneal disease.

METHODS

A retrospective chart review was conducted from 2012 to 2015. Demographics, comorbidities, intraoperative variables, and postoperative outcomes were analyzed and compared between the non-AWR group and the AWR group.

RESULTS

A total of 30 patients underwent CRS-HIPEC at our institution; 19 recruited in non-AWR group and 11 in the AWR arm. Median follow-up was 19.1 mo for the non-AWR group and 15.6 mo for AWR. Overall survival and complications were not significantly different between groups. Six patients in the non-AWR group and three patients in AWR group died during the follow-up period (32% versus 27%, P = 0.75). Grade III/IV Clavien-Dindo complications were similar in AWR compared to non-AWR group (64% versus 50%, P = 0.46) however estimated blood loss (1000 mL versus 450 mL, P = 0.01) and operative time (663 min versus 510 min, P = 0.02) were significantly increased in the AWR group.

CONCLUSIONS

The results of this study demonstrate that AWR is a safe and viable option and can improve wound closure and strength in select patient populations undergoing CRS-HIPEC. AWR is not associated with an increase in mortality or complication rate. Future studies will need larger sample sizes and randomization to identify patient and operative factors that increase morbidity with AWR and identify the ideal timing of AWR.

Efficacy of Nootka Oil as a Biopesticide for Management of Imported Fire Ants (Hymenoptera: Formicidae)

Recent concerns regarding the impact of traditional synthetic pesticides on nontarget organisms have generated demand for alternative products with lower environmental impact. This demand has led to increasing focus on plant essential oils as sources of new biopesticides. In this study, we demonstrate that the essential oil of the Alaskan yellow cedar, Cupressus nootkatensis (D. Don) Spach, has activity against hybrid imported fire ant workers, Solenopsis invicta Buren × Solenopsis richteri Forel. In digging assays, ants were repelled by nootka oil and digging continued to be suppressed by nearly 50% in nootka oil-treated sand aged 6 mo in the laboratory. Higher worker mortality was also observed in contact and fumigation assays compared to control checks. In a field drench test, mortality of mounds treated with nootka oil lagged behind mounds treated with bifenthrin treatment for 7 wk, but both nootka oil and bifenthrin had higher mortality than the untreated check at the end of the 12-wk evaluation period. In a band application evaluation, nootka oil plots maintained a 90-95% reduction in fire ant mounds from the 2nd to 17th wk, when new mounds began to intrude on the field plots. The quarantine-approved bifenthrin band treatment maintained 100% control from the 2nd to 24th wk. Although the formulation tested here did not perform to Federal Imported Fire Ant Quarantine standards, other formulations may enable this product to reach 100% control. In addition, nootka oil could be beneficial in situations where ant suppression rather than complete quarantine elimination is the management goal.

Impact of a counter-rotating planetary rotation system on thin-film thickness and uniformity

Planetary rotation systems incorporating forward- and counter-rotating planets are used as a means of increasing coating-system capacity for large oblong substrates. Comparisons of planetary motion for the two types of rotating systems are presented based on point tracking for multiple revolutions as well as comparisons of quantitative thickness and uniformity. Counter-rotation system geometry is shown to result in differences in thin-film thickness relative to standard planetary rotation for precision optical coatings. This systematic error in thin-film thickness will reduce deposition yields for sensitive coating designs.

Impact of deposition-rate fluctuations on thin-film thickness and uniformity

Variations in deposition rate are superimposed on a thin-film deposition model with planetary rotation to determine the impact on film thickness. Variations in magnitude and frequency of the fluctuations relative to the speed of planetary revolution lead to thickness errors and uniformity variations up to 3%. Sufficiently rapid oscillations in the deposition rate have a negligible impact, while slow oscillations are found to be problematic, leading to changes in the nominal film thickness. Superimposing noise as a random fluctuation in the deposition rate has a negligible impact, confirming the importance of any underlying harmonic oscillations in the deposition rate or source operation.

Analysis of a planetary-rotation system for evaporated optical coatings

The impact of planetary design considerations for optical coating deposition is analyzed, including the ideal number of planets, variations in system performance, and the deviation of planet motion from the ideal. System capacity is maximized for four planets, although substrate size can significantly influence this result. Guidance is provided in the design of high-performance deposition systems based on the relative impact of different error modes. Errors in planet mounting such that the planet surface is not perpendicular to the axis of rotation are particularly problematic, suggesting planetary design modifications would be appropriate.

Abstract P2-09-21: HBOC genetic counseling: A genetic counselor-physician partnership model

Background: In 2003, the American Society of Clinical Oncology (ASCO) issued a policy statement that addressed the oncologist's role in integrating cancer genetic risk assessment and management into clinical practice. ASCO supports access to genetic counseling for patients offered genetic testing and after results disclosure. In 2014, Integrated Genetics (IG) began offering genetic counseling in partnership with OBGYNs and oncologists whose patients have a personal or family history of breast or ovarian cancer. The goal of the program was to provide an easily accessible and comprehensive genetic counseling service for Hereditary Breast and Ovarian Cancer (HBOC) to meet the needs of patients and to support clinicians who currently provide pre- and post-test counseling.

Methods: In this study we describe IG's HBOC genetic counseling service and in a retrospective analysis, describe the characteristics of patients referred to the program in 2014. Clinicians were provided a toll free number for patients to call to schedule a genetic counseling session. The scheduling staff facilitated medical record requests and emailed a family history questionnaire. In person or telegenetic counseling (via WebEx) was offered. Telegenetic counseling allowed the patient and genetic counselor to see one another via webcam and view counseling visual aids and relevant medical records. Pedigree analysis and cancer genetic risk assessment were performed and genetic testing options discussed based on National Comprehensive Cancer Network (NCCN) testing criteria. Information discussed at the session, including patient decisions about testing, was documented for the referring physician and patient in the Genetic Counseling Consultation Report. The physician ordered testing and managed patient screening and surveillance.

Results: During 2014, 247 counseling sessions were provided to patients from 23 states. All patients had a personal or family history of breast or ovarian cancer and the average age of patients was 44 years (range: 16-85). Sixty four percent (64%) of sessions were done via WebEx and 36% in person. Of the 247 sessions, 198 (80.2%) were for pre-test genetic counseling; of those, 173 (87.4%) met NCCN HBOC genetic testing criteria and genetic testing for BRCA1/2 was offered. Of this group, 70.52% desired testing, 27.75% declined and 1.73% were undecided. The remaining sessions (n=49) included post-test counseling for pathogenic mutations or variants of unknown significance (n=39), and patients who had accepted testing but whose results were pending (n=10).

Conclusions: The IG HBOC genetic counseling program extended comprehensive genetic counseling to patients at increased risk for BRCA1/2 mutations who might not otherwise have access to this service. Physicians appropriately selected patients for referral (87% met NCCN testing criteria). The genetic counselors provided cancer genetic risk assessment, time-intensive patient education to facilitate informed decision making, and counseling about the implications of results, including the complexities of variants of unknown significance. This partnership model allowed physicians to retain patient care oversight, including management of screening and surveillance, while leveraging genetic counselor expertise.

Citation Format: Oliver JB, Cronister A. HBOC genetic counseling: A genetic counselor-physician partnership model. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P2-09-21.

The effect of body mass index (BMI) and nutrition on morbidity and mortality in patients undergoing cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS-HIPEC)

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Background: In patients with peritoneal malignancies undergoing CRS-HIPEC, their weight and nutritional factors may be affected by the presence of cachexia or obesity. With the potential morbidity of these radical operations, the selection of patients is paramount. BMI and albumin have long been utilized to predict outcomes in surgical patients. Our study evaluated whether BMI and albumin had an impact on CRS-HIPEC morbidity and mortality. Methods: Demographics, comorbidities, intraoperative variables and post-operative outcomes were analyzed using a retrospective database comprising of 28 patients undergoing CRS-HIPEC at our institution from 2012 to 2015. Median BMI of 25 and median albumin of 3.8 were used to compare the 2 groups. Primary outcome was overall survival, while secondary outcomes included complications, length of stay and intraoperative variables. Results: Patients were organized into 2 groups: < 25 BMI (n = 13) and > 25 BMI (n = 15). Albumin levels were assigned to each group and demonstrated similar values (4.0 vs 3.8, p = 0.44). Demographic data described similarly aged (54 vs 56 years, p = 0.42), gender (92% vs 93% females, p = 0.92), and peritoneal carcinomatosis index (21 vs 18, p = 0.60). The > 25 BMI group had slightly higher number of comorbidities (Charlson Comorbidity Index > 0 in 23% vs 60%, p = 0.04). Both had similar operative times (566 vs 549 minutes, p = 0.73), blood loss (700 vs 550 ml, p = 0.96) and median numbers of organs removed during cytoreduction (4 vs 3, p = 0.28). Length of stay was no different between the 2 groups (11.5 vs 10.5 days, p = 0.86). Six of the thirteen < 25 BMI individuals died during follow up (mean 5.6 months) compared to only two of the fifteen > 25 BMI individuals (mean 10.2 months) (p = 0.01). Conclusions: In our single center series, patients > 25 BMI had a better survival when compared to < 25 BMI patients. However, the analysis of the albumin levels did not demonstrate a statistically significant difference. There were no other significant differences in preoperative, intraoperative or other post-operative outcomes. Higher powered studies with longer follow-up are needed to confirm our results.

A comparison of long-term outcomes of portal versus systemic venous drainage in pancreatic transplantation: a systematic review and meta-analysis

Pancreas transplantation venous effluent can be drained via the portal vein or the systemic circulation; however, no recommendation exists for the ideal technique. A systematic review of the literature from 1989 through 2014 using PubMed, CINHAL, and Cochrane Library for portal versus systemic venous drainage was undertaken. Only studies on humans and published in English were considered. Measures of glycemic control and total cholesterol were synthesized for meta-analysis utilizing random-effects models. Of 166 articles retrieved, 15 articles were included for meta-analysis. Patient and graft survival were comparable in a large database study as well as in the only randomized control study. No differences in complications were seen when exocrine drainage was enteric for the systemic venous group. Fasting insulin (-34.13 pmol/mL, p < 0.001) was significantly lower within the portal drained group; however, fasting blood glucose levels (-3.4 mg/dL, p = 0.32) and hemoglobin A1C levels (mean difference 0.124%, p = 0.25) were comparable. Total cholesterol levels (-3.62 mg/dL, p = 0.447), as well as other measures of lipids, showed no difference. Based on this systematic review and meta-analysis, there is no evidence of differences in outcomes or metabolic control in patients undergoing pancreatic transplant with portal venous drainage compared to the systemic venous drainage.

Nano-indentation of single-layer optical oxide thin films grown by electron-beam deposition

Mechanical characterization of optical oxide thin films is performed using nano-indentation, and the results are explained based on the deposition conditions used. These oxide films are generally deposited to have a porous microstructure that optimizes laser induced damage thresholds, but changes in deposition conditions lead to varying degrees of porosity, density, and possibly the microstructure of the thin film. This can directly explain the differences in the mechanical properties of the film studied here and those reported in literature. Of the four single-layer thin films tested, alumina was observed to demonstrate the highest values of nano-indentation hardness and elastic modulus. This is likely a result of the dense microstructure of the thin film arising from the particular deposition conditions used.

Sensitivity of cytology and immunohistochemistry for diagnosis of pancreaticobiliary cancer

TPS490

Background: Biliary strictures present a diagnostic challenge to differentiate benign disease from hepatopancreaticobiliary (HPB) malignancies. ERCP cytology is commonly performed in these patients; however, its sensitivity for diagnosis of HPB malignancy is poor (41.6%). Many adjunctive tests have been investigated to improve the sensitivity of HPB biopsies. In a recent meta-analysis by our group the best immunohistochemical (IHC) stains were a combination of IMP3, S100A4, and standard cytology. IHC stains for S100P and pVHL negativity were also helpful. Based on this meta-analysis we have designed a retrospective analysis of old cell block specimens to demonstrate the sensitivity and specificity of a combination IHC staining panel in detecting HPB maliganancies. Methods: Retrospective IHC staining will be carried out on old cell blocks from ERCP brushings and EUS-FNA. Expression of IMP3, S100A4, S100P, and pVHL will be determined. Using this panel as a combination we will determine its sensitivity and specificity on 200 patient samples. We will further determine how many stains are necessary to achieve maximum sensitivity by subtraction of data from one or more IHC stains followed by repeating sensitivity calculations. Finally, we will calculate the cost of conducting these tests and determine the cost-benefit ratio of employing these tests in the wider clinical setting. Conclusions: Overall we feel these studies will advance the precision with which clinicians can determine the presence of HPB malignancy in patients undergoing biopsy. This will ultimately lead to fewer patients with benign disease undergoing resection unnecessarily.