A porcine model of thoracic aortic aneurysms created with a retrievable drug infusion stent graft mirrors human aneurysm pathophysiology.

Objective: Aneurysm pathophysiology remains poorly understood, in part from the disparity of murine models with human physiology and the requirement for invasive aortic exposure to apply agents used to create aneurysm models. A retrievable drug infusion stent graft (RDIS) was developed to isolate the aortic wall intraluminally for drug exposure. We hypothesized that an RDIS could deliver aneurysm-promoting enzymes to create a porcine model of thoracic aneurysms without major surgical exposure. Methods: Retrievable nitinol stent graft frames were designed with an isolated drug delivery chamber, covered with polytetrafluoroethylene, and connected to a delivery wire with a drug infusion catheter installed to the outer chamber. Institutional Animal Care and Use Committee-approved Yorkshire pigs (n = 5) underwent percutaneous access of the femoral artery, baseline aortogram and stent placement in the thoracic aorta followed by 30-minute exposure to a cocktail of elastase, collagenase, and trypsin. After aspiration of excess drug, stent retrieval, and femoral artery repair, animals were recovered, with angiograms at 1 and 4 weeks followed by explant. Histological analysis, in situ zymography, and multiplex cytokine assays were performed. Results: The RDIS isolated a segment of anterior aorta angiographically, while the center lumen preserved distal perfusion during drug treatment (baseline femoral mean arterial pressure, 70 ± 14 mm Hg; after RDIS, 75 ± 12; P = .55). Endovascular induction of thoracic aneurysms did not require prior mechanical injury and animals revealed no evidence of toxicity. Within 1 week, significant aneurysmal growth was observed in all five animals (1.4 ± 0.1 cm baseline to 2.9 ± 0.7 cm; P = .002) and only within the treated region of the aorta. Aneurysms persisted out to 4 weeks. Aneurysm histology demonstrated loss of elastin and collagen that was otherwise preserved in untreated aorta. Proinflammatory cytokines and increased matrix metalloproteinase activity were increased significantly within the aneurysm. Conclusions: An RDIS achieves isolated drug delivery while preserving distal perfusion to achieve an endovascular porcine model of thoracic aneurysms without major surgery. This model may have value for surgical training, device testing, and to better understand aneurysm pathogenesis. Most important, although the RDIS was used to simulate aortic pathology, this tool offers intriguing horizons for focused therapeutic drug delivery directly to aneurysms and, more broadly, focused locoregional drug delivery to vessels and vascular beds.

Determinants of Long Waiting Time to Kidney Transplantation.

BACKGROUND: Disparity in waiting time to kidney transplantation led to new policy (KAS250). Our aims were to identify variables associated with long wait time (LWT); assess the impact of KAS250 on WT; and analyze modifiable transplant center behaviors correlated with WT. METHODS: SRTR data for adult deceased donor kidney transplants were analyzed. Time-periods from 8/1/2018-7/31/2019 and 5/1/2021-4/30/2022 were chosen for pre- and post-KAS250 analyses. Transplant centers were categorized as LWT or SWT centers depending on whether pre-KAS250 median center waiting times were greater or less than the national pre-KAS250 median waiting time of 57.8 months. RESULTS: In multivariate analysis, transplantation with HCV NAT negative kidneys was associated with an additional 21.3 months of WT (CI: 18.5-24.2, P < .0001), and transplantation with KDPI <85% kidneys was associated with an additional 10.8 months (CI: 8.2-13.3, P < .0001). Post-KAS250 national kidney transplant waiting time decreased from 61-58 months (P < .0001) and waiting time at LWT centers decreased from 74-69 months (P < .0001). Cold ischemic times (CIT) increased (20.2 hours vs 18.3 hours, P < .0001) and DGF rates also increased (32.7% vs 31.0%, P < .0001). Centers generally displayed more aggressive transplantation practices post-KAS250 however significant differences in DCD utilization, organ offer acceptance ratios and tolerance for long CIT persist between SWT and LWT centers. CONCLUSION: KAS250 has reduced waiting time disparities between SWT and LWT centers at the cost of increased CIT and DGF and reduced allocation efficiency. Significant differences in transplant practice persist between SWT and LWT centers.

A self calibrating, magnetic sensor approach accurately positions an aortic damage control stent in a porcine model.

Objectives: Non-compressible torso hemorrhage remains a high mortality injury, with difficulty mobilizing resources before exsanguination. Previous studies reported on a retrievable stent graft for damage control and morphometric algorithms for rapid placement, yet fluoroscopy is impractical for the austere environment. We hypothesized that magnetic sensors could be used to position stents relative to an external magnet placed on an anatomic landmark, whereas an electromagnet would allow self-calibration to account for environmental noise. Methods: A magnetic sensor alone (MSA) and with integrated stent (MSIS) were examined in a porcine model under anesthesia. A target electromagnet was placed on the xiphoid process (position 0 cm). Sensors were placed in the aorta and measurements obtained at positions 0 cm, +4 cm, and +12 cm from the magnet and compared with fluoroscopy. Sensors were examined under conditions of tachycardia/hypertension, hypotension, vibration, and metal shrapnel to simulate environmental factors that might impact accuracy. General linear models compared mean differences between fluoroscopy and sensor readings. Results: Both sensors were compatible with a 10 French catheter system and provided real-time assessment of the distance between the sensor and magnetic target in centimeters. Mean differences between fluoroscopy and both magnetic sensor readings demonstrated accuracy within ±0.5 cm for all but one condition at 0 cm and +4 cm, whereas accuracy decreased at +12 cm from the target. Using the control as a reference, there was no significant difference in mean differences between fluoroscopy and both MSA or MSIS readings at 0 cm and +4 cm for all conditions. The system retained effectiveness if the target was overshot. Conclusion: Magnetic sensors achieved the highest accuracy as sensors approached the target. Oscillation of the electromagnet on and off effectively accounts for environmental noise.This approach is promising for rapid and accurate placement of damage control retrievable stent grafts when fluoroscopy is impractical. Level of evidence: Not applicable.

A dumbbell rescue stent graft facilitates clamp-free repair of aortic injury in a porcine model.

Objective: Noncompressible torso hemorrhage is a high-mortality injury. We previously reported improved outcomes with a retrievable rescue stent graft to temporize aortic hemorrhage in a porcine model while maintaining distal perfusion. A limitation was that the original cylindrical stent graft design prohibited simultaneous vascular repair, given the concern for suture ensnarement of the temporary stent. We hypothesized that a modified, dumbbell-shaped design would preserve distal perfusion and also offer a bloodless plane in the midsection, facilitating repair with the stent graft in place and improve the postrepair hemodynamics. Methods: In an Institutional Animal Care and Use Committee-approved terminal porcine model, a custom retrievable dumbbell-shaped rescue stent graft (dRS) was fashioned from laser-cut nitinol and polytetrafluoroethylene covering and compared with aortic cross-clamping. Under anesthesia, the descending thoracic aorta was injured and then repaired with cross-clamping (n = 6) or dRS (n = 6). Angiography was performed in both groups. Operations were divided into phases: (1) baseline, (2) thoracic injury with either cross-clamp or dRS deployed, and (3) recovery, after which the clamp or dRS were removed. Target blood loss was 22% to simulate class II or III hemorrhagic shock. Shed blood was recovered with a Cell Saver and reinfused for resuscitation. Renal artery flow rates were recorded at baseline and during the repair phase and reported as a percentage of cardiac output. Phenylephrine pressor requirements were recorded. Results: In contrast with cross-clamped animals, dRS animals demonstrated both operative hemostasis and preserved flow beyond the dRS angiographically. Recovery phase mean arterial pressure, cardiac output, and right ventricular end-diastolic volume were significantly higher in dRS animals (P = .033, P = .015, and P = .012, respectively). Whereas distal femoral blood pressures were absent during cross-clamping, among the dRS animals, the carotid and femoral MAPs were not significantly different during the injury phase (P = .504). Cross-clamped animals demonstrated nearly absent renal artery flow, in contrast with dRS animals, which exhibited preserved perfusion (P<.0001). Femoral oxygen levels (partial pressure of oxygen) among a subset of animals further confirmed greater distal oxygenation during dRS deployment compared with cross-clamping (P = .006). After aortic repair and clamp or stent removal, cross-clamped animals demonstrated more significant hypotension, as demonstrated by increased pressor requirements over stented animals (P = .035). Conclusions: Compared with aortic cross-clamping, the dRS model demonstrated superior distal perfusion, while also facilitating simultaneous hemorrhage control and aortic repair. This study demonstrates a promising alternative to aortic cross-clamping to decrease distal ischemia and avoid the unfavorable hemodynamics that accompany clamp reperfusion. Future studies will assess differences in ischemic injury and physiological outcomes. Clinical Relevance: Noncompressible aortic hemorrhage remains a high-mortality injury, and current damage control options are limited by ischemic complications. We have previously reported a retrievable stent graft to allow rapid hemorrhage control, preserved distal perfusion, and removal at the primary repair. The prior cylindrical stent graft was limited by the inability to suture the aorta over the stent graft owing to risk of ensnarement. This large animal study explored a dumbbell retrievable stent with a bloodless plane to allow suture placement with the stent in place. This approach improved distal perfusion and hemodynamics over clamp repair and heralds the potential for aortic repair while avoiding complications.

Ten-year outcomes following ventral hernia repair: making the case for better post-market surveillance in the USA.

BACKGROUND: We sought to identify the 10-year complication and recurrence rates and associated sociodemographic and operative characteristics associated with non-mesh versus mesh-based ventral hernia repairs (VHRs). METHODS: This was an IRB-approved (2020H0317) retrospective longitudinal study of patients undergoing mesh or non-mesh VHR from 2009-2019 at a single tertiary-care institution. The electronic medical record was used to collect sociodemographic, clinical, and intraoperative details, and early (≤ 30 days) and long-term (> 30-day) postoperative complications. Up to ten-year follow-up was obtained for long-term complications, categorized as: hernia recurrence reoperation (HRR), major complications requiring emergency surgery (MCES) (defined as non-elective operations related to the abdominal wall), and non-recurrence procedural intervention (NRPI) (defined as any procedures related to the abdominal wall, bowel, or mesh). Kaplan-Meier survival curves were obtained for each long-term complication. RESULTS: Of the 645 patients identified, the mean age at index operation was 52.51 ± 13.57 years with 50.70% female. Of the index operations, 21.24% were for a recurrence. Procedure categories included: 57.36% incisional, 37.21% non-incisional umbilical, 8.22% non-incisional epigastric, 3.88% parastomal, 0.93% diastasis recti, and 0.47% Spigelian hernias. Operative approaches included open (n = 383), laparoscopic (n = 267), and robotic (n = 21). Fascial closure (81.55%) and mesh use (66.2%) were performed in the majority of cases. Median follow-up time was 2098 days (interquartile range 1320-2806). The rate of short-term complications was 4.81% for surgical site infections, 15.04% for surgical site occurrences, and 13.64% for other complications. At 10 years, the HRR-free survival probability was 85.26%, MCES-free survival probability was 94.44%, and NRPI-free survival probability was 78.11%. CONCLUSIONS: A high proportion of patients experienced long-term recurrence and complications requiring intervention after index VHR. For many patients, a ventral hernia develops into a chronic medical condition. Improved efforts at post-market surveillance of operative approaches and mesh location and type should be undertaken to help optimize outcomes.

Impact of post-discharge phone calls on non-urgent hospital returns < 90 days following primary bariatric surgery.

INTRODUCTION: Quality of care delivery may improve patient outcomes post-bariatric surgery. We examined the quality of post-discharge phone calls (PhDC) to determine the impact on early (< 90 day) non-urgent hospital returns (NUHR) following primary bariatric surgery. METHODS: A retrospective review was performed on patients who underwent Roux-en-Y-gastric bypass (RYGB) or sleeve gastrectomy (SG) in 2019. Patients were compared between presence of care coaching (Jan-June 2019) versus no care coaching (July-Dec 2019). Baseline demographics, comorbidities, psychiatric history, and PhDC were collected. Index PhDCs were coded for completeness using a scoring system and rated by call quality. Patients were stratified into NUHR versus control group (Never returns [NR]). Primary analysis examined the impact of PhDC on NUHR. Sub-analysis examined the impact of call quality. Univariate analysis was performed using Chi-square or Fisher's exact tests. Multivariate analysis (MVA) was used to determine predictors of NUHR. A p-value of ≤ 0.05 was statistically significant. RESULTS: A total of 359 patients were included. Compared to the NR group (n = 294), NUHRs (n = 65) were more likely to be younger (41.3 + 12.1 versus 45.0 + 10.8 years, p = 0.024), with baseline anxiety (41.5% versus 23.5%, p = 0.003), and undergo RYGB (73.3% versus 57.8%, p = 0.031). There was a significant difference in number of PhDC in the NUHR and NR groups (p = 0.0206). Care-coached patients had significantly higher rates of high-quality phone calls (p < 0.0001) compared to non-care-coached patients. MVA demonstrated younger age (OR = 0.97, CI: 0.95-1.00; p = 0.023), anxiety (OR = 2.09, CI: 1.17-3.73; p = 0.012), RYGB (OR = 1.88, CI: 1.02-3.45; p = 0.042), and > 50% call quality versus no PhDC (OR = 0.45, CI: 0.25-0.83; p = 0.010) were independently associated with NUHRs. CONCLUSION: High-quality PhDCs may play a role in mitigating NUHRs. Care coaching represents a potential intervention to decrease high rates of NUHR in primary bariatric surgery patients.

Preventable operating room delays in robotic-assisted thoracic surgery: Identifying opportunities for cost reduction.

BACKGROUND: This study aimed to characterize the types of intraoperative delays during robotic-assisted thoracic surgery, operating room staff awareness/perceptions of delays, and cost impact of delays on overall operative costs. METHODS: Robotic-assisted thoracic surgery cases from May to August 2019 were attended by 3 third-party observers to record intraoperative delays. The postoperative surveys were given to operating room staff to elicit perceived delays. Observed versus perceived delays were compared using the McNemar test. Direct costs and charges per delay were calculated. RESULTS: Forty-four cases were observed, of which a majority were lobectomies (n = 38 [86%]). A total of 71 delays were recorded by observers, encompassing 75% of cases (n = 33), with an average delay length of 3.6 minutes (±5.3 minutes). The following delays were observed: equipment failure (n = 40, average delay length 5.0 minutes (±6.5 minutes), equipment missing (n = 15, 2.2 minutes [±1.4 minutes]), staff unfamiliarity with equipment (n = 4, 3.4 minutes [± 1.5 minutes]), and other (n = 12, 4.5 minutes [±5.3 minutes]). The detection rates for any intraoperative delay were consistently lower for all of the operating room team members compared with observers, including surgeons (34.3% vs 77.1%; P = .0003), first assistants (41.9% vs 74.2%; P = .0075), surgical technologists (39.4% vs 72.7%; P = .0045), and circulating nurses (41.18% vs 76.47% minutes; P = .0013). The average operating room variable direct cost of delays based on the average total delay length per case was $225.52 (±$350.18) and was 1.6% (range 0-10.6%) of the total case charges. CONCLUSION: The lack of perception of intraoperative delays hinders operating teams from effectively closing the variable cost gaps. Future studies are needed to explore methods of increasing perception of delays and opportunities to improve operating room efficiency.

Increasing Frailty in Geriatric Emergency General Surgery: A Cause for Concern.

BACKGROUND: Emergency general surgery (EGS) presents a challenge for frail, geriatric individuals who often have extensive comorbidities affecting postoperative recovery. Previous studies have shown an association between increasing frailty and adverse outcomes following elective and EGS; no study has explored the same for the geriatric patient population using the modified 5-item frailty index (mFI-5) score. MATERIALS AND METHODS: A retrospective cohort study was performed using the 2012-2017 American College of Surgeons - National Surgical Quality Improvement Program database to identify geriatric patients (≥65 years) undergoing EGS procedures within 48 h of admission. The previously validated mFI-5 score was used to assess preoperative frailty. The study cohort was divided into four groups: mFI-5 = 0, mFI-5 = 1, mFI-5 = 2, and mFI-5 ≥ 3; the impact of increasing mFI-5 score on failure-to-rescue (FTR), 30-day complications, readmissions, reoperations, and mortality was assessed. RESULTS: A total of 47,216 patients were included: 27.4% with mFI-5 = 0, 45% with mFI-5 = 1, 22.1% with mFI-5 = 2, and 5.5% with mFI-5 ≥ 3. Following multivariate analyses, increasing mFI-5 score was associated with higher odds of FTR (mFI-5 = 1: odds ratio (OR) 1.48, p=0.003; mFI-5 = 2: OR 2.66, p <0.001; mFI-5 ≥ 3: OR 3.97, p <0.001), 30-day complications (mFI-5 = 1: OR 1.46, p <0.001; mFI-5 = 2: OR 2.48, p <0.001; mFI-5≥3: OR 5.01, p <0.001), reoperation (mFI-5 = 1: OR 1.42, p = 0.020; mFI-5 = 2: OR 1.70, p = 0.021; mFI-5 ≥ 3: OR 2.18, p = 0.009) and all-cause mortality (mFI-5 = 1: OR 1.49, p=0.001; mFI-5 = 2: OR 2.67, p <0.001; mFI-5 ≥ 3: 3.96, p <0.001). CONCLUSIONS: Increasing frailty in geriatric EGS patients is associated with significantly higher rates of FTR, 30-day complications, reoperations, and all-cause mortality. The mFI-5 score can be used to assess frailty and better anticipate the postoperative course of vulnerable geriatric patients.