The Association Between a Surgeon’s Learning Curve With Endovascular Aortic Aneurysm Repair and Previous Institutional Experience

Endovascular aneurysm repair offers a survival advantage and is cost-effective compared with conservative management in patients physiologically unfit for open repair

OBJECTIVE

The endovascular aneurysm repair-2 (EVAR-2) trial suggested that EVAR in patients unfit for open surgical repair (OSR) failed to provide a significant overall survival advantage compared with conservative management. The aim is to compare survival and cost-effectiveness in patients with poor cardiopulmonary exercise test (CPET) metrics who underwent EVAR or were managed conservatively.

METHODS

A prospective database of all CPETs (1435 patients) performed to assess preoperative fitness for abdominal aortic aneurysm repair was maintained. A total of 350 patients deemed unfit for OSR underwent EVAR or were managed conservatively. A 1:1 propensity-matched analysis incorporating age, gender, anaerobic threshold, and aneurysm size was used to compare survival. Cost-effectiveness analysis was based on the economic model for the National Institute for Health and Care Excellence clinical guideline on abdominal aortic aneurysm treatment.

RESULTS

Propensity matching produced 122 pairs of patients in the EVAR and conservative management groups. The median overall survival for the EVAR group was significantly longer than that for the conservative management group (84 vs 30 months, P < .001). One-, three-, and five-year mortality in the EVAR group was 7%, 40%, and 68%, respectively, compared with 25%, 68%, and 82% in the conservative management group, all P < .001. The increment cost-effectiveness ratio for EVAR was £8023 (US$11,644) per quality-adjusted life year gained compared with £430,602 (US$624,967) in the National Institute for Health and Care Excellence guideline, which is based on EVAR-2 results.

CONCLUSIONS

EVAR offers a survival advantage and is cost-effective in selected patients deemed unfit for OSR based on CPET compared with conservative management.

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.

Reporting standards for endovascular aortic repair of aneurysms involving the renal-mesenteric arteries

Endovascular aortic aneurysm repair of complex aortic aneurysms requires incorporation of side branches using specially designed aortic stent grafts with fenestrations, directional branches, or parallel stent grafts. These techniques have been increasingly used and reported in the literature. The purpose of this document is to clarify and to update terminology, classification systems, measurement techniques, and end point definitions that are recommended for reports dealing with endovascular repair of complex abdominal and thoracoabdominal aortic aneurysms involving the renal and mesenteric arteries.

Learning curve of fenestrated and branched endovascular aortic repair for pararenal and thoracoabdominal aneurysms

OBJECTIVE

The objective of this study was to review the learning curve for fenestrated-branched endovascular aortic repair (F-BEVAR) of pararenal and thoracoabdominal aortic aneurysms (TAAAs).

METHODS

We reviewed the clinical data of 334 consecutive patients (255 males, mean age 75 ± 7 years) who underwent F-BEVAR between 2007 and 2016 in a single institution. Outcomes were analyzed in four quartiles of experience (Q1-Q4). Study outcomes included trends in patient characteristics, device design, procedural variables, 30-day mortality, and major adverse events (MAEs).

RESULTS

There were 178 patients (53%) treated for pararenal aneurysms and 156 (47%) for TAAAs. During the study period, there was a statistically significant increase in the proportion of TAAAs and in the number of vessels incorporated. Despite this, there was a steady decrease in 30-day mortality (6% in Q1 to 0% in Q4; P < .04) and in the rate of MAEs (60% in Q1 to 29% in Q4; P<.001). By linear regression analysis, there was significant decline in estimated blood loss (1358 ± 1517 mL in Q1 to 486 ± 520 mL in Q4; P < .001), total operating time (325 ± 116 minutes in Q1 to 248 ± 92 minutes in Q4; P < .001), total fluoroscopy time (121 ± 59 minutes in Q1 to 85 ± 39 minutes in Q4; P < .001), contrast volume (201 ± 92 mL in Q1 to 160 ± 61 mL in Q4; P = .002), and radiation dose (4141 ± 2570 mGy in Q2 to 2543 ± 1895 mGy in Q4; P < .001). Independent predictors of MAEs were total operating time (odds ratio [OR], 1.6; 95% confidence interval [CI], 1.3-1.8; P < .001), Society for Vascular Surgery total score (OR, 1.1; 95% CI, 1.02-1.2; P = .009), and quartile 1 (OR, 3.0; 95% CI, 1.7-5.2; P < .001).

CONCLUSIONS

This study demonstrates significant improvement in perioperative mortality, MAEs, procedural variables, and secondary interventions in patients treated by F-BEVAR, despite the increase in complexity of aneurysm pathology during the study period. Also, better patient selection contributed to improve outcomes.

Endovascular Aneurysm Repair May Provide a Survival Advantage in Patients Deemed Physiologically Ineligible for Open Abdominal Aortic Aneurysm Repair

BACKGROUND

Cardiopulmonary exercise testing (CPET) provides an objective assessment of functional capacity and fitness. It can be used to guide decision making prior to major vascular surgery. The EVAR-2 trial suggested that endovascular aneurysm repair (EVAR) in patients unfit for open repair failed to provide a significant survival advantage over nonsurgical management. The aim of this study is to assess contemporary survival differences between patients with poor CPET measures who underwent EVAR or were not offered surgical intervention.

METHODS

A prospectively maintained database of CPET results of patients considered for elective infrarenal aortic aneurysm repair were interrogated. Anaerobic threshold (AT) of <11 mL/min/kg was used to indicate poor physical fitness. Hospital electronic records were then reviewed for perioperative, reintervention, and long-term outcomes.

RESULTS

Between November 2007 and October 2017, 532 aortic aneurysm repairs were undertaken, of which 376 underwent preoperative CPET. Seventy patients were identified as having an AT <11 mL/min/kg. Thirty-seven patients underwent EVAR and 33 were managed nonsurgically. All-cause survival at 1, 3, and 5 years for those patients who underwent EVAR was 97%, 92%, and 81%, respectively. For those not offered surgical intervention survival at the same points was 72%, 48%, and 24% [hazard ratio, HR = 5.13 (1.67-15.82), P = 0.004]. Aneurysm-specific survival at 1, 3, and 5 years for those patients who underwent EVAR was 97%, 94%, and 94%, respectively. Survival at the same time points for those not offered surgical intervention was 90%, 69%, and 39%, respectively [HR = 7.48 (1.37-40.82), P = 0.02].

CONCLUSIONS

In this small, retrospective, single-center, nonrandomized cohort, EVAR may provide a survival advantage in patients with poor physical fitness identified via CPET. Randomized studies with current generation EVAR are required to validate the results shown here.

Trends in elective and ruptured abdominal aortic aneurysm repair by practice setting in Ontario, Canada, from 2003 to 2016: a population-based time-series analysis

BACKGROUND

Recent years have seen centralization of vascular surgery services in Ontario. We sought to examine the trends in overall and approach-specific elective and ruptured abdominal aortic aneurysm repair by hospital type (teaching v. community).

METHODS

We conducted a population-based time-series analysis of elective and ruptured abdominal aortic aneurysm repairs in Ontario, Canada, from 2003 to 2016. Quarterly cumulative incidences of repairs per 100 000 Ontarians aged 40 years and older were calculated. We fit exponential smoothing models to the data stratified by approach and hospital type to examine repair trends.

RESULTS

We identified 19 219 elective and 2722 ruptured repairs between 2003 and 2016. The cumulative incidences of overall elective repair and elective open surgical repair decreased by 1.15% (p = 0.008) and 67% (p < 0.001), respectively, in teaching hospitals and by 23% (p < 0.001) and 60% (p < 0.001), respectively, in community hospitals. The cumulative incidence of elective endovascular repair increased 667% in teaching hospitals (p < 0.001). Elective endovascular repair began in community centres after 2010 and increased to 0.98/100 000 (p < 0.001), resulting in a rebound in overall elective repair in the community. Overall ruptured repairs and ruptured open repairs decreased by 84% (p < 0.001) and 88% (p = 0.002), respectively, at community hospitals. Ruptured endovascular repairs at community hospitals increased from no procedures before 2006 to 0.03/100 000 in 2016 (p = 0.005).

INTERPRETATION

There has been substantial uptake of endovascular aortic repair in teaching and community hospitals in Ontario, and community hospital uptake of endovascular repair has begun decentralization of abdominal aortic aneurysm repair. Increased experience and training in endovascular repair and reduced specialized care requirements will probably lead to continued decentralization.

Two-Year Outcomes of the Nellix EndoVascular Aneurysm Sealing System for Treatment of Abdominal Aortic Aneurysms

Purpose: To analyze the 2-year outcomes of endovascular aneurysm sealing (EVAS) according to 2 versions of the instructions for use (IFU). Methods: A retrospective study was conducted involving 355 consecutive patients treated with the first-generation EVAS device from April 2013 to December 31, 2015, at 3 high-volume centers. Out of 355 patients treated with EVAS, 264 were elective asymptomatic infrarenal EVAS procedures suitable for analysis. In this cohort, 168 (63.3%) patients were treated within the IFU 2013 criteria; of these 48 (18.2%) were in compliance with the revised IFU 2016 version. Results: Overall technical success was 98.2% (165/168) in the IFU 2013 group and 97.9% (47/48) in the IFU 2016 subgroup (p=0.428). The 2-year freedom from reintervention estimates were 89.7% (IFU 2013) and 95.7% (IFU 2016), with significantly more reinterventions in the first 45 cases (p=0.005). The stenosis/occlusion estimates were 6.5% (IFU 2013) and 4.2% (IFU 2016; p=0.705). Nine (5.4%) endoleaks (8 type Ia and 1 type Ib) were observed within the IFU 2013 cohort; 3 (2.1%) were in the IFU 2016 subgroup (p=0.583). Migration ≥10 mm or ≥5 mm requiring intervention was reported in 12 (7.1%) patients in the IFU 2013 cohort but none within the IFU 2016 subgroup. Ten (6.0%) patients demonstrated aneurysm growth in the IFU 2013 cohort, of which 2 (4.2%) were in the IFU 2016 subgroup. Overall survival and freedom from aneurysm-related death estimates at 2 years were 90.9% and 97.6% in the IFU 2013 cohort (IFU 2016: 95.5% and 100.0%). The prevalence of complications seemed lower within IFU 2016 without significant differences. Conclusion: This study shows acceptable 2-year results of EVAS used within the IFU, without significant differences between the 2 IFU versions, though longer follow-up is indicated. The refined IFU significantly reduced the applicability of the technique.

Low mortality rates after endovascular aortic repair expand use to high-risk patients

OBJECTIVE

The 2010 endovascular aneurysm repair (EVAR) trial 2 (EVAR 2) reported that patients with comorbidity profiles rendering them unfit for open aneurysm repair who underwent EVAR did not experience a survival advantage compared with those who did not undergo intervention. These patients experienced a 30-day mortality of 7.3%, whereas reports from similar cohorts reported far lower mortality rates. The primary objective of our study was to compare the incidence of 30-day mortality in low- and high-risk patients undergoing EVAR in a contemporary data set, using patient risk stratification criteria from EVAR 2. Secondarily, we sought to identify risk factors associated with a disproportionate contribution to 30-day mortality risk.

METHODS

Data were obtained from the 2005 to 2013 American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) Participant Use Data Files (N = 24,813). Patients were included in the high-risk cohort with the presence of renal, respiratory, or cardiac preoperative criteria alone or in combination. Renal impairment criteria were defined as dialysis and creatinine concentration >2.26 mg/dL. Respiratory impairment criteria included history of chronic obstructive pulmonary disease and preoperative ventilator support. Cardiac impairment criteria included history of myocardial infarction, congestive heart failure, angina, and prior coronary intervention. Patient and procedural characteristics and 30-day postoperative outcomes were compared using Pearson χ2 tests for categorical variables and Wilcoxon rank sum tests for continuous variables.

RESULTS

Among 24,813 patients undergoing EVAR, 12,043 (48%) patients were characterized as high risk (at least one impairment criterion); 12,770 (52%) patients were stratified as low risk. The 30-day mortality rate was 1.9% in the high-risk cohort compared with the 7.3% reported by EVAR 2, and it was higher in the high-risk cohort compared with the low-risk cohort (1.9% vs 0.9%; P < .001). Whereas the presence of each comorbidity increased the odds of 30-day mortality (respiratory odds ratio [OR], 1.62; 95% confidence interval [CI], 1.16-2.26; P = .005; cardiac OR, 1.55; 95% CI, 1.14-2.10; P = .005), the presence of renal criteria disproportionately increased the odds of mortality threefold (OR, 3.42; 95% CI, 2.31-5.09; P < .001).

CONCLUSIONS

Contemporary 30-day mortality after EVAR in high-risk patients is substantially lower than that reported in the EVAR 2 trial. Whereas low- and high-risk stratification by current comorbidity criteria is appropriate, attention needs to be paid to disproportionate risk contribution from renal disease to mortality compared with cardiac and pulmonary comorbidities. Given the lower mortality risk than previously described, patients stratified as high risk should be thoughtfully considered for definitive EVAR.

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

The purpose of this study was to report the learning curve of endovascular aneurysm repair (EVAR) based on the Zenith stent graft (Cook Medical Inc., Bloomington, IN). In the last 9 years, 101 patients were treated with a Zenith stent graft. To display the learning curve, a cumulative sum (CUSUM) failure analysis curve of the 30-day technical success rate was calculated. For detailed analysis, our EVAR patient cohort was chronologically divided into three groups. Technical and clinical results, basic patient parameters, and procedural data were compared. The CUSUM graph indicated an initial sharp rise within the first 35 cases and a plateau thereafter. The 30-day technical success rate significantly increased from the first to the second group (83 vs. 100%; p = 0.019), as did the primary technical success rate (66 vs. 97%; p = 0.001). EVAR based on the Zenith stent graft required ∼35 cases to reach a stably high rate of short-term technical success.

Does a relationship exist between the number of thoracoscopic thymectomies performed and the learning curve for thoracoscopic resection of thymoma in patients with myasthenia gravis?

This study aimed to analyze surgeons' learning curve for thymoma resection with video-assisted thoracoscopic surgery (VATS). Two hundred and eleven myasthenia gravis patients had VATS thymic resections, including 25 patients with a thymoma. Three groups of surgeries, according to the order of operations, were analyzed: Group A comprised the first 70 thymectomies, Group B comprised the second 70 thymectomies, and Group C comprised the final 71 thymectomies. We compared the groups on a set of preoperative (age, gender, body mass index, and Osserman stage), operative (number in each group, size, and Masaoka stage), and postoperative (complications and length of stay) variables. A significant difference was observed in the number of thymoma operations (Group A: four patients, Group B: seven patients, and Group C: 14 patients; P: 0.031) and the duration of operation (Group A: 66 min, Group B: 52 min, and Group C: 48 min; P: 0.024). A strong correlation was found between the duration of operation and order of patients (Pearson r: -0.554, P: 0.000). We recommend the start of a program for the resection of thymoma with VATS after surgical staff have performed 70 VATS thymectomy operations.

Logistic Considerations for a Successful Institutional Approach to the Endovascular Repair of Ruptured Abdominal Aortic Aneurysms

The value of emergency endovascular aneurysm repair (EVAR) in the setting of ruptured abdominal aortic aneurysm remains controversial owing to differing results. However, interpretation of published results remains difficult as there is a lack of generally accepted protocols or standard operating procedures. Furthermore, such protocols and standard operating procedures often are reported incompletely or not at all, thereby making interpretation of results difficult. We herein report our integrated logistic system for the endovascular treatment of ruptured abdominal aortic aneurysms. Important components of this system are prehospital logistics, in-hospital treatment logistics, and aftercare. Further studies should include details about all of these components, and a description of these logistic components must be included in all future studies of emergency EVAR for ruptured abdominal aortic aneurysms.

Learning curve analysis of thoracic endovascular aortic repair in relation to credentialing guidelines

OBJECTIVE

Recently, practice guideline documents have recommended the completion of different levels of interventional experience and 5 or 10 thoracic endovascular aortic cases prior to surgeon credentialing. This study's purpose was to determine whether these requirements are valid by reviewing three surgeons' learning curves with thoracic aortic endovascular repairs.

METHODS

Between 1998 and 2006, 67 patients underwent emergent or elective endovascular repair of thoracic aortic pathologies by one of three vascular surgeons with extensive experience with catheter manipulation and abdominal aortic endografts. Following standard retrospective review, each surgeon's learning curve was analyzed using the cumulative sum failure method with a target success rate of 95% derived from the literature. The main outcome variable was primary technical success.

RESULTS

These 67 patients presented with several pathologies including elective (n = 31) and ruptured (n = 11) thoracic aortic aneurysms, acute dissections or aortic ulcers (n = 10), and acute blunt thoracic aortic trauma (n = 15). The mean age was 65 (range: 20 to 90) and the early (30 day) mortality rate was 19.4% in urgent cases (n = 36) and 0% in elective cases (n = 31). Paraplegia occurred in two patients (3%). Primary technical success was achieved in 62 cases (92.5%) and did not differ between surgeons (92.6%, 91.3%, 94.1%, respectively; P = .9). Each surgeon's cases were plotted sequentially and the resulting learning curves were similar. Although acceptable outcomes were obtained throughout the study period, improved results, compared with the target success rate, were not achieved until each surgeon treated 5 to 10 patients.

CONCLUSION

This study supports the case volume requirements of the Society for Vascular Surgery credentialing guidelines, which also requires extensive catheter and guidewire experience. With this background in catheter manipulation and endovascular abdominal aortic repair, surgeons can achieve optimal outcomes with thoracic aortic lesions following 5 to 10 cases.