Looking for a Learning Curve in EVAR Based on the Zenith Stent Graft

Real-world comparative claims analysis of a novel single-branched aortic stent graft device versus thoracic endograft placement with extra-anatomic debranching/revascularization in zone 2 aortic disease

Background

Thoracic endovascular aortic repair (TEVAR) involving landing zone 2 can require extra-anatomic debranching (SR-TEVAR) to ensure left subclavian artery perfusion, resulting in increased costs. A single-branch device (Thoracic Branch Endoprosthesis [TBE], WL Gore, Flagstaff, AZ) provides a total endovascular solution. Comparative cost analysis of patients undergoing zone 2 TEVAR requiring left subclavian artery preservation with TBE versus SR-TEVAR is presented.

Methods

A single-center retrospective cost analysis was performed for aortic diseases requiring a zone 2 landing zone (TBE vs. SR-TEVAR) from 2014 to 2019. Facility charges were collected from the universal billing form UB-04 (form CMS 1450).

Results

Twenty-four patients were included in each arm. There were no significant differences in the overall mean procedural charges between the two groups: TBE, $209,736 ($57,761) vs. SR-TEVAR $209,025 ($93,943), P = 0.94. TBE resulted in reduced operating room charges ($36,849 [$8750] vs. $48,073 [$10,825], P = 0.02) and reduced intensive care unit and telemetry room charges, which did not reach statistical significance (P = 0.23 and 0.12, respectively). Device/implant charges were the primary cost driver in both groups. Charges associated with TBE were significantly higher: $105,525 ($36,137) vs. $51,605 ($31,326), P > 0.01.

Conclusions

TBE had similar overall procedural charges despite higher device/implant-related expenses and reduced facility resource utilization (lower operating room, intensive care unit, telemetry, and pharmacy charges).

Step, Error, and Event Frameworks in Endovascular Aortic Repair

OBJECTIVE

Competency-based surgical education requires detailed and actionable feedback to ensure adequate and efficient skill development. Comprehensive operative capture systems such as the Operating Room Black Box (ORBB; Surgical Safety Technologies, Inc), which continuously records and synchronizes multiple sources of intraoperative data, have recently been integrated into hybrid rooms to provide targeted feedback to endovascular teams. The objective of this study is to develop step, error, and event frameworks to evaluate technical performance in elective endovascular aortic repair (EVAR) comprehensively captured by the ORBB (Surgical Safety Technologies, Inc; Toronto, Canada).

METHODS

This study is based upon a modified Delphi consensus process to create evaluation frameworks for steps, errors, and events in EVAR. International experts from Vascular Surgery and Interventional Radiology were identified, based on their records of publications and invited presentations, or serving on relevant journal editorial boards. In an initial open-ended survey round, experts were asked to volunteer a comprehensive list of steps, errors, and events for a standard EVAR of an infrarenal aorto-iliac aneurysm (AAA). In subsequent survey rounds, the identified items were presented to the expert panel to rate on a 5-point Likert scale. Delphi survey rounds were repeated until the process reached consensus with a predefined agreement threshold (Cronbach α>0.7). The final frameworks were constructed with items achieving an agreement (responses of 4 or 5) from greater than 70% of experts.

RESULTS

Of 98 invited proceduralists, 38 formed the expert consensus panel (39%), consisting of 29 vascular surgeons and 9 interventional radiologists, with 34% from North America and 66% from Europe. Consensus criteria were met following the third round of the Delphi consensus process (Cronbach α=0.82-0.93). There were 15, 32, and 25 items in the error, step, and event frameworks, respectively (within-item agreement=74%-100%).

CONCLUSION

A detailed evaluation tool for the procedural steps, errors, and events in infrarenal EVAR was developed. This tool will be validated on recorded procedures in future work: It may focus skill development on common errors and hazardous steps. This tool might be used to provide high-quality feedback on technical performance of trainees and experienced surgeons alike, thus promoting surgical mastery.

Association between thoracoabdominal aneurysm extent and mortality after complex endovascular repair

OBJECTIVE

Traditional open surgical repair of thoracoabdominal aortic aneurysms (TAAAs) has historically resulted in 30-day mortality rates ranging from 6% to 20%, depending on the Crawford anatomic extent. Although short-term survival is important, long-term survival is essential for patients to benefit from these often elective and potentially morbid procedures. The aneurysm extent affects the long-term survival after open repair; however, effect on endovascular repair is unknown and could influence the decision process for repair. We evaluated the association between aneurysm extent and survival and identified patient and perioperative factors associated with mortality after endovascular repair.

METHODS

A retrospective cohort of patients treated for TAAAs recorded in the Society for Vascular Surgery Vascular Quality Initiative thoracic and complex endovascular aneurysm repair registry were evaluated. All patients treated for asymptomatic degenerative aneurysms from 2010 to 2019 were included. Crawford extent I to V was defined according to the proximal and distal landing zones documented in the registry. Patients without extension into the visceral aorta were used for comparison and categorized as having extent 0a or 0b, depending on the distal landing zone in the thoracic aorta. Kaplan-Meier plots were used to estimate survival, and Cox proportional hazard regression models were created to identify the predictors of mortality.

RESULTS

From 2010 to 2019, 15,333 patients were entered into the registry, of whom 2062 met the inclusion criteria. The Crawford extent was 0a for 379, 0b for 848, I for 81, II for 98, III for 130, IV for 454, and V for 72. Three groups were created in accordance with the similar outcomes noted on a preliminary analysis: (1) extent 0a and 0b; (2) extent I, II, and III; and (3) extent IV and V. The mean survival time for the extent 0a and 0b group was 70.7 ± 1.43 months and was 48.6 ± 1.65 months for the extent I, II, and III group and 57.6 ± 1.24 months for the extent IV and V group. The corresponding 1-year mortality was 8.4%, 18.4%, and 7.8%. Cox regression analysis identified the following preoperative factors were associated with mortality: chronic obstructive pulmonary disease (odds ratio [OR], 1.70; P < .001), Crawford extent I to III (OR, 1.64; P = .015), preexisting chronic kidney disease (OR, 1.37; P = .024), and age per year (OR, 1.03; P < .001). A number of postoperative factors were also associated with mortality.

CONCLUSIONS

Similar to open TAAA repair, patients with more extensive aortic disease treated with endovascular repair had worse 1-year and long-term survival. The extent of aortic disease and anticipated postoperative survival should factor prominently into the surgical decision-making process for elective endovascular TAAA repair.

A methodology for in silico endovascular repair of abdominal aortic aneurysms

Endovascular aneurysm repair (EVAR) can involve some unfavorable complications such as endoleaks or stent-graft (SG) migration. Such complications, resulting from the complex mechanical interaction of vascular tissue, SG and blood flow or incompatibility of SG design and vessel geometry, are difficult to predict. Computational vascular mechanics models can be a predictive tool for the selection, sizing and placement process of SGs depending on the patient-specific vessel geometry and hence reduce the risk of potential complications after EVAR. In this contribution, we present a new in silico EVAR methodology to predict the final state of the deployed SG after intervention and evaluate the mechanical state of vessel and SG, such as contact forces and wall stresses. A novel method to account for residual strains and stresses in SGs, resulting from the precompression of stents during the assembly process of SGs, is presented. We suggest a parameter continuation approach to model various different sizes of SGs within one in silico EVAR simulation which can be a valuable tool when investigating the issue of SG oversizing. The applicability and robustness of the proposed methods are demonstrated on the example of a synthetic abdominal aortic aneurysm geometry.

The light at the end of the tunnel: a single-operator learning curve analysis for per oral endoscopic myotomy

BACKGROUND

Per oral endoscopic myotomy (POEM) represents a natural orifice transluminal endoscopic surgery approach to Heller myotomy. Our center was the first to offer POEM outside of Japan, allowing us to accumulate what is likely the highest single-operator POEM volume in the United States.

OBJECTIVE

To define the POEM learning curve of a gastroenterologist by using a larger data set and more detailed statistical analysis than used in 2 other reports of POEM performed by surgeons.

DESIGN

Prospective cohort study.

SETTING

Tertiary-care academic medical center.

PATIENTS

We analyzed the first 93 consecutive POEMs on patients with achalasia aged >18 years without contraindications to POEM performed by a single operator from October 2009 to November 2013.

INTERVENTIONS

(1) Efficiency estimation via cumulative sum (CUSUM) analysis, (2) mastery estimation via penalized basis-spline regression and CUSUM analysis, (3) correlation of operator experience with clinical outcomes (Eckardt score improvement, lower esophageal sphincter pressure reduction) and technical errors (accidental mucosotomy rate), and (4) unadjusted and adjusted regression analysis to assess how patient characteristics affected procedure time by using a generalized linear model.

MAIN OUTCOME MEASUREMENTS

Clinical outcomes, procedure time, technical errors.

RESULTS

Efficiency was attained after 40 POEMs and mastery after 60 POEMs. When we used the adjusted regression analysis, only case number (operator experience) significantly affected procedure time (P < .0001). Improvements in clinical outcomes were excellent but not significantly affected by operator experience, as was the case with accidental mucosotomies. Procedure time was not significantly affected by age, sex, achalasia stage, baseline lower esophageal sphincter pressure, baseline Eckardt score, prior treatment of achalasia, prior botulinum toxin injection, incidence of accidental mucosotomies, length of myotomy, or type of knife used (all P > .05).

LIMITATIONS

Our analysis may underestimate the number of POEMs required to achieve mastery for operators with limited or no endoscopic submucosal dissection experience.

CONCLUSION

These results offer thresholds for efficiency and mastery of a single gastroenterologist operator that may guide the efforts of novice POEM operators.