Predicting risk of rupture and rupture-preventing reinterventions following endovascular abdominal aortic aneurysm repair

Association between Diabetes Status and Long-term Outcomes Following Open and Endovascular Repair of Infrarenal Abdominal Aortic Aneurysms

OBJECTIVE

Current literature reports conflicting findings regarding the effect of diabetes mellitus (DM) on outcomes of AAA repair. In this study we examined the effect of DM and its management on outcomes following open (OAR) and endovascular (EVAR) AAA repair.

METHODS

We identified all patients undergoing OAR or EVAR for infrarenal AAA between 2003-2018 in the Vascular Quality Initiative (VQI) registry data linked with Medicare claims. We excluded patients with missing DM status. Patients were stratified by their preoperative DM status, and then further stratified by DM management: dietary, non-insulin anti-diabetic medications (NIM), or insulin. Outcomes of interest included one-year aneurysm sac dynamics, 8-year aneurysm rupture, reintervention, and all-cause mortality. These outcomes were analyzed with chi-square, Kaplan-Meier methods, and multivariable cox regression analyses.

RESULTS

We identified 34,021 EVAR patients and 4,127 OAR patients of which 20% and 16% had DM, respectively. Of all DM patients, 22% were managed by dietary management, 59% by NIM, and 19% by insulin. Following EVAR, DM patients were more likely to have stable sacs while non-DM patients were more likely to have sac regression at 1 year. Compared with non-DM, DM was associated with a significantly lower risk for 8-year rupture in EVAR (EVAR HR: 0.68 [0.51-0.92]). Compared with non-DM, NIM was associated with lower risk of rupture within 8-years for both EVAR and OAR (EVAR HR: 0.64 [0.44-0.94]; OAR HR: 0.29 [0.41-0.80]), while dietary and insulin had similar rupture risk compared with non-DM. However, compared with non-DM, DM was associated with higher risk of 8-year all-cause mortality following EVAR and OAR (DM vs. non-DM: EVAR HR: 1.17 [1.11-1.23]; OAR HR: 1.16 [1.00-1.36]). Following further DM management sub-stratification, compared with non-DM, management with NIM and insulin were associated with higher 8-year mortality in EVAR and OAR (EVAR: NIM HR: 1.12 [1.05-1.20] & insulin HR: 1.40 [1.26-1.55]; OAR: NIM HR: 1.27 [1.06-1.54] & insulin HR: 1.57 [1.15-2.13]). Finally, there was a similar risk of reintervention across the DM and non-DM populations in EVAR and OAR.

CONCLUSION

DM was associated with lower adjusted risk of rupture following EVAR as well as OAR in patients managed with NIM. Nevertheless, just as in patients without AAA, preoperative DM was associated with a higher adjusted risk of all-cause mortality. Further study is needed to evaluate for differences in aneurysm-related mortality between DM and non-DM, and studies are planned to evaluate the independent effect of NIM on aneurysm-related outcomes.

Implantable Pressure-Sensing Devices for Monitoring Abdominal Aortic Aneurysms in Post-Endovascular Aneurysm Repair

Over the past two decades, there has been extensive research into surveillance methods for the post-endovascular repair of abdominal aortic aneurysms, highlighting the importance of these technologies in supplementing or even replacing conventional image-screening modalities. This review aims to provide an overview of the current status of alternative surveillance solutions for endovascular aneurysm repair, while also identifying potential aneurysm features that could be used to develop novel monitoring technologies. It offers a comprehensive review of these recent clinical advances, comparing new and standard clinical practices. After introducing the clinical understanding of abdominal aortic aneurysms and exploring current treatment procedures, the paper discusses the current surveillance methods for endovascular repair, contrasting them with recent pressure-sensing technologies. The literature on three commercial pressure-sensing devices for post-endovascular repair surveillance is analyzed. Various pre-clinical and clinical studies assessing the safety and efficacy of these devices are reviewed, providing a comparative summary of their outcomes. The review of the results from pre-clinical and clinical studies suggests a consistent trend of decreased blood pressure in the excluded aneurysm sac post-repair. However, despite successful pressure readings from the aneurysm sac, no strong link has been established to translate these measurements into the presence or absence of endoleaks. Furthermore, the results do not allow for a conclusive determination of ongoing aneurysm sac growth. Consequently, a strong clinical need persists for monitoring endoleaks and aneurysm growth following endovascular repair.

Design and Characterisation of a Read-Out System for Wireless Monitoring of a Novel Implantable Sensor for Abdominal Aortic Aneurysm Monitoring

Abdominal aortic aneurysm (AAA) is a dilation of the aorta artery larger than its normal diameter (>3 cm). Endovascular aneurysm repair (EVAR) is a minimally invasive treatment option that involves the placement of a graft in the aneurysmal portion of the aorta artery. This treatment requires multiple follow-ups with medical imaging, which is expensive, time-consuming, and resource-demanding for healthcare systems. An alternative solution is the use of wireless implantable sensors (WIMSs) to monitor the growth of the aneurysm. A WIMS capable of monitoring aneurysm size longitudinally could serve as an alternative monitoring approach for post-EVAR patients. This study has developed and characterised a three-coil inductive read-out system to detect variations in the resonance frequency of the novel Z-shaped WIMS implanted within the AAA sac. Specifically, the spacing between the transmitter and the repeater inductors was optimised to maximise the detection of the sensor by the transmitter inductor. Moreover, an experimental evaluation was also performed for different orientations of the transmitter coil with reference to the WIMS. Finally, the FDA-approved material nitinol was used to develop the WIMS, the transmitter, and repeater inductors as a proof of concept for further studies. The findings of the characterisation from the air medium suggest that the read-out system can detect the WIMS up to 5 cm, regardless of the orientation of the Z-shape WIMS, with the detection range increasing as the orientation approaches 0°. This study provides sufficient evidence that the proposed WIMS and the read-out system can be used for AAA expansion over time.

A Greek Multicentre Study Assessing the Outcome of Late Rupture After Endovascular Abdominal Aortic Aneurysm Repair

OBJECTIVE

Late rupture after endovascular aortic aneurysm repair (EVAR) for an abdominal aortic aneurysm (AAA) is an increasing complication associated with a high mortality rate. This study aimed to analyse the causes and outcomes in patients with AAA rupture after EVAR.

METHODS

A multi-institutional Greek study of late ruptures after EVAR between 2008 - 2022 was performed. Primary outcomes were intra-operative and in hospital death.

RESULTS

A total of 70 patients presented with late rupture after EVAR (proportion of ruptured EVARs among all EVARs, 0.6%; 69 males; mean age 77.2 ± 6.7 years). The mean time interval between EVAR and late rupture was 72.3 months (range 6 - 180 months). In all cases the cause of rupture was the presence of an endoleak (type I, 73%) with sac enlargement. Moreover, 34% of subjects with rupture after EVAR had been lost to follow up and 32% underwent a secondary intervention. Additionally, 57 patients (81%) were treated by conversion to open surgical repair (COSR) and the remainder by endovascular correction of endoleak (ECE). Eleven intra-operative deaths (16%) were recorded. The overall in hospital mortality rate was 41% (23% ECE vs. 46% COSR; p = .21). Of the patients who presented as initially haemodynamically stable, 23% died during hospitalisation, while the respective mortality rate for patients who presented as unstable was 78% (odds ratio [OR] 11.8, 95% confidence interval [CI] 3.6 - 39.1; p < .001). Multivariable logistic regression analysis revealed that severity of haemodynamic shock was the most significant risk factor for intra-operative (OR 7.15, 95% CI 1.58 - 32.40; p = .010) and in hospital death (OR 9.53, 95% CI 2.79 - 32.58; p < .001).

CONCLUSION

These data underline the devastating prognosis of late rupture after EVAR. Haemodynamic status at presentation was an important predictive factor for death both in the ECE and COSR groups. Rigorous follow up and prompt evaluation of an unstable patient in case of rupture after EVAR is recommended.

Ultrasound Surveillance is Feasible After Endovascular Aneurysm Repair

BACKGROUND

Surveillance after endovascular aneurysm repair (EVAR) is traditionally done with computed tomography angiography (CTA) scans that exposes patient to radiation, nephrotoxic contrast media, and potentially increased risk for cancer. Ultrasound (US) is less labor intensive and expensive and might thus provide a good alternative for CTA surveillance. The aim of this study was to evaluate in real-life patient cohorts whether US is able to detect post-EVAR aneurysm-related complications similarly to CTA.

METHODS

This retrospective study compared the outcome of consecutive patients who underwent EVAR for intact abdominal aortic aneurysm and were surveilled solely by CTA (CTA-only cohort, n = 168) in 2000-2010 or by combined CTA and US (CTA/US cohort, n = 300) in 2011-2016, as a standard surveillance protocol in the department of vascular surgery, Helsinki University Hospital. The CTA-only patients were imaged at 1, 3, and 12 months and annually thereafter. The CTA/US patients were imaged with CTA at 3 and 12 months, US at 6 months and annually thereafter. If there were suspicion of >5 mm aneurysm growth, CTA scan was performed. The patients were reviewed for imaging data, reinterventions, aneurysm ruptures, and death until December 2018. The 2 groups were compared for secondary rupture, aneurysm-related and cancer-related death, reintervention related to abdominal aortic aneurysm, and maximum aneurysm diameter increase ≥5 mm. The mean follow-up in the CTA-only cohort was 67 months and in CTA/US cohort 43 months.

RESULTS

The 2 cohorts were alike for basic characteristics and for the mean aneurysm diameter. The total number of CT scans for detecting aneurysm was 84.1/100 patient years in the CTA-only cohort compared to 74.5/100 patient years for US/CTA cohort. Forty percent of patients under combined CTA/US surveillance received 1 or more additional CTA scans. The 2 cohorts did not differ for 1-year, 5-year and 8-year freedom from aneurysm related death, secondary sac rupture, nor the incidence of rupture preventing interventions.

CONCLUSIONS

Based on the follow-up data of this real-life cohort of 468 patients, combined surveillance with US and additional CTA either per protocol or due to suspicion of aneurysm-related complications had comparable outcome with sole CTA-surveillance. Thus, US can be considered a reasonable alternative for the CTA. However, our study showed also that the need of additional CTAs due to suspicion of endoleak or aneurysm nonrelated reasons is substantial.

Re-Rupture 2 Years after Endovascular Aortic Aneurysm Repair Rupture

Re-rupture 2 years after endovascular aortic aneurysm repair (EVAR) rupture is an extremely rare event and limited data exist in the literature. We present an interesting case of a patient with an abdominal aortic rupture that had undergone 2 years before an endovascular repair for rupture after EVAR due to a type IA endoleak. The patient underwent a successful embolization of the type IA endoleak. Onyx was used to seal the gutter between the aortic wall and the endograft and the 1-month post-embolization CT showed complete sealing with no contrast in the sac. Two years after the rupture, he was presented again with clinical signs of hemodynamic shock and instability. An urgent CT Angiograph showed again rupture due to a type IA endoleak. The patient underwent an emergency open laparotomy. We analyze the re-rupture after EVAR while taking data from the literature into account.

Individual Patient Data Meta-Analysis of 10-Year Follow-Up after Endovascular and Open Repair for Ruptured Abdominal AorticAneurysms

BACKGROUND

Endovascular aortic repair (EVAR) has conferred an early survival advantage compared to an open surgical repair (OSR) in patients with ruptured abdominal aortic aneurysms (rAAA). However, the long-term survival benefit after EVAR was not displayed among randomized controlled trials (RCTs), whereas many non-RCTs have provided conflicting results. We conducted a time-to-event individual patient data (IPD) meta-analysis on long-term rAAA data.

METHODS

All studies comparing mortality after EVAR versus OSR for rAAA were included. We used restricted mean survival times (RMSTs) as a measure of life expectancy for EVAR and OSR.

RESULTS

A total of 21 studies, including 12,187 patients (4952 EVAR and 7235 OSR) were finally deemed eligible. A secondary IPD analysis included 725 (372 EVAR and 353 OSR) patients only from the 3 RCTs (Immediate Management of the Patient With Rupture : Open Versus Endovascular Repair, Endovasculaire ou Chirurgie dans les Anévrysmes aorto-iliaques Rompus and Amsterdam Acute Aneurysm Trial trials). Among all studies, the median survival was 4.20 (95% confidence interval [CI]: 3.70-4.58) years for EVAR and 1.91 (95% CI: 1.57-2.39) years for OSR. Although EVAR presented with increased hazard risk from 4 to 7 years, which peaked at 6 years after the operation, the RMST difference was 0.54 (95% CI: 0.35-0.73; P < 0.001) years gained with EVAR at the end of the 10-year follow-up. IPD meta-analysis of RCTs did not demonstrate significant differences.

CONCLUSIONS

At 10-years follow-up, EVAR was associated with a 6.5 month increase in life expectancy when compared to OSR after analyzing all eligible studies. Evidence from our study suggests that a strict follow-up program would be desirable, especially for patients with long-life expectancy.

Identifying high risk for proximal endograft failure after EVAR in patients suitable for both open and endovascular elective aneurysm repair

INTRODUCTION

Proximal endograft failure (type Ia endoleak or migration) after endovascular aneurysm repair (EVAR) is associated with hostile aneurysm neck morphology. Neck scoring systems were developed to predict proximal endograft failure but were studied in retrospective studies, which due to selection bias may have led to an overestimation of bad outcomes after EVAR. To predict patients who benefit from open repair, preoperative neck morphology and occurrence of long-term proximal endograft failure were investigated in patients enrolled in the endovascular arm of the DREAM-trial who were suitable for open repair by definition and have long-term follow-up.

METHODS

A post-hoc on-treatment analysis of patients after EVAR was performed in 171 patients. Aneurysm neck morphology was quantified using the aneurysm severity grading (ASG)-neck score calculated on pre-operative CT-angiography images. The ASG-neck score was used to predict proximal endograft failure. ROC analysis was performed to calculate a threshold to divide favorable and unfavorable aneurysm necks (low and high-risk), positive and negative likelihood-ratios were calculated accordingly. Freedom from proximal endograft failure was compared between groups using Kaplan Meier analysis.

RESULTS

During a median follow-up of 7.6 years, 20 patients suffered proximal endograft failure. ROC analysis showed an AUC 0.77 (95% CI 0.65-0.90; p<0.001) indicating acceptable prediction. The threshold was determined at ASG-neck score ≥5, 30 patients had unfavorable neck morphology of whom 11 developed proximal endograft failure. The positive likelihood-ratio was 4.4 (95% CI 2.5-7.8) and the negative likelihood-ratio was 0.51 (95% CI 0.3-0.8). Twelve years postoperatively, freedom from proximal endograft failure was 91.7% in favorable and 53.2% in unfavorable groups, difference 38.5% (95% CI 13.9-63.1; p<0.001).

CONCLUSION

In this study, the ASG-neck score predicted proximal endograft failure during the entire follow-up. This exhibits the persistent risk for proximal endograft failure long after EVAR and calls for ongoing surveillance especially in patients with unfavorable aneurysm necks.

Patient-specific computational modeling of endovascular aneurysm repair: State of the art and future directions

Endovascular aortic repair (EVAR) has become the preferred intervention option for aortic aneurysms and dissections. This is because EVAR is much less invasive than the alternative open surgery repair. While in-hospital mortality rates are smaller for EVAR than open repair (1%-2% vs. 3%-5%), the early benefits of EVAR are lost after 3 years due to larger rates of complications in the EVAR group. Clinicians follow instructions for use (IFU) when possible, but are left with personal experience on how to best proceed and what choices to make with respect to stent-graft (SG) model choice, sizing, procedural options, and their implications on long-term outcomes. Computational modeling of SG deployment in EVAR and tissue remodeling after intervention offers an alternative way of testing SG designs in silico, in a personalized way before intervention, to ultimately select the strategies leading to better outcomes. Further, computational modeling can be used in the optimal design of SGs in cases of complex geometries. In this review, we address some of the difficulties and successes associated with computational modeling of EVAR procedures. There is still work to be done in all areas of EVAR in silico modeling, including model validation, before models can be applied in the clinic, but much progress has already been made. Critical to clinical implementation are current efforts focusing on developing fast algorithms that can achieve (near) real-time solutions, as well as ways of dealing with inherent uncertainties related to patient aortic wall degradation on an individualized basis. We are optimistic that EVAR modeling in the clinic will soon become a reality to help clinicians optimize EVAR interventions and ultimately reduce EVAR-associated complications.

Long Term Outcomes of Post-Implantation Syndrome After Endovascular Aneurysm Repair

OBJECTIVE

The aim of this study was to investigate the association between post-implantation syndrome (PIS) and long term outcomes, with emphasis on cardiovascular prognosis.

METHODS

One hundred and forty-nine consecutive patients undergoing EVAR in a tertiary institution were previously included in a study investigating the risk factors and short term consequences of PIS (defined as tympanic temperature ≥ 38°C and CRP > 10 mg/L, after excluding complications with an effect on inflammatory markers). This study was based on a prospectively maintained database. Survival status was derived from inquiry of civil registry database information and causes of death from the Dutch Central Bureau of Statistics. The primary endpoint was cardiovascular events. Secondary endpoints were overall and specific cause mortality (cardiovascular, ischaemic heart disease, AAA, and cancer related mortality). Aneurysm sac dynamics and occurrence of endoleaks were also analysed. Survival estimates were obtained using Kaplan-Meier plots and a multivariable model was constructed to correct for confounders.

RESULTS

The PIS incidence was 39% (58/149). At the time of surgery, patients had a mean age of 73 ± 7 years and were predominantly male. There were no baseline differences between the PIS and non-PIS groups. The median follow up was 6.4 years (3.2 - 8.3), similar in both groups (p = .81). There was no difference in cardiovascular events for PIS and non-PIS patients (p = .63). However, Kaplan-Meier plots suggest a trend towards a higher rate of cardiovascular events in PIS patients during the first years: freedom from cardiovascular events at one year was 94% vs. 89% and at three years 90% vs. 82%. No differences were found in overall and specific cause mortality. There was a higher rate of type II endoleaks for non-PIS patients (28% vs. 9%, p = .005). Sac dynamics were similar in both groups.

CONCLUSION

The results suggest that PIS is not associated with a statistically significantly higher risk of cardiovascular events. PIS had no impact on mortality. Lastly, PIS patients had fewer type II endoleaks, but sac dynamics were analogous.

Long-term Reintervention After Endovascular Abdominal Aortic Aneurysm Repair

OBJECTIVE

To describe the long-term reintervention rate after endovascular abdominal aortic aneurysm repair (EVR), and identify factors predicting reintervention.

SUMMARY OF BACKGROUND DATA

EVR is the most common method of aneurysm repair in America, and reintervention after EVR is common. Clinical factors predicting reintervention have not been described in large datasets with long-term follow-up.

METHODS

We studied patients who underwent EVR using the Vascular Quality Initiative registry linked to Medicare claims. Our primary outcome was reintervention, defined as any procedure related to the EVR after discharge from the index hospitalization. We used classification and regression tree modeling to inform a multivariable Cox-regression model predicting reintervention after EVR.

RESULTS

We studied 12,911 patients treated from 2003 to 2015. Mean age was 75.5 ± 7.3 years, 79.9% were male, and 89.1% of operations were elective. The 3-year reintervention rate was 15%, and the 10-year rate was 33%. Five factors predicted reintervention: operative time ≥3.0 hours, aneurysm diameter ≥6.0 cm, an iliac artery aneurysm ≥2.0 cm, emergency surgery, and a history of prior aortic surgery. Patients with no risk factors had a 3-year reintervention rate of 12%, and 10-year rate of 26% (n = 7310). Patients with multiple risk factors, such as prior aortic surgery and emergent surgery, had a 3-year reintervention rate 72%, (n = 32). Modifiable factors including EVR graft manufacturer or supra-renal fixation were not associated with reintervention (P = 0.76 and 0.79 respectively).

CONCLUSIONS

All patients retain a high likelihood of reintervention after EVR, but clinical factors at the time of repair can predict those at highest risk.

Modelling the impact of changes to abdominal aortic aneurysm screening and treatment services in England during the COVID-19 pandemic

Background

The National Health Service (NHS) abdominal aortic aneurysm (AAA) screening programme (NAAASP) in England screens 65-year-old men. The programme monitors those with an aneurysm, and early intervention for large aneurysms reduces ruptures and AAA-related mortality. AAA screening services have been disrupted following COVID-19 but it is not known how this may impact AAA-related mortality, or where efforts should be focussed as services resume.

Methods

We repurposed a previously validated discrete event simulation model to investigate the impact of COVID-19-related service disruption on key outcomes. This model was used to explore the impact of delayed invitation and reduced attendance in men invited to screening. Additionally, we investigated the impact of temporarily suspending scans, increasing the threshold for elective surgery to 7cm and increasing drop-out in the AAA cohort under surveillance, using data from NAAASP to inform the population.

Findings

Delaying invitation to primary screening up to two years had little impact on key outcomes whereas a 10% reduction in attendance could lead to a 2% lifetime increase in AAA-related deaths. In surveillance patients, a 1-year suspension of surveillance or increase in the elective threshold resulted in a 0.4% increase in excess AAA-related deaths (8% in those 5–5.4cm at the start). Longer suspensions or a doubling of drop-out from surveillance would have a pronounced impact on outcomes.

Interpretation

Efforts should be directed towards encouraging men to attend AAA screening service appointments post-COVID-19. Those with AAAs on surveillance should be prioritised as the screening programme resumes, as changes to these services beyond one year are likely to have a larger impact on surgical burden and AAA-related mortality.

Systematic review of embolization of type I endoleaks using liquid embolic agents

OBJECTIVE

The long-term success of endovascular aneurysm repair (EVAR) is limited by complications, most importantly endoleaks. In case of (persistent) type I endoleak (T1EL), secondary intervention is indicated to prevent secondary aneurysm rupture. Different treatment options are suggested for T1ELs, such as endo anchors, (fenestrated) cuffs, embolization, or open conversion. Currently, the treatment of T1EL with liquid embolic agents is available; however, results are not yet addressed. This review presents the safety and efficacy of embolization with liquid embolic agents for treatment of T1ELs after EVAR.

METHODS

A systematic literature search was performed for all studies reporting the use of liquid embolic agents as monotherapy for treatment of T1ELs after EVAR. Patient numbers, technical success (successful delivery of liquid embolics in the T1EL) and clinical success (absence of aneurysm related death, endoleak recurrence or additional interventions during follow-up) were examined.

RESULTS

Of 1604 articles, 10 studies met the selection criteria, including 194 patients treated with liquid embolics; 73.2% of the patients were male with a median age of 71 years. The overall technical success was 97.9%. Clinical success was 87.6%. Because the median follow-up was only 13.0 months (range, 1-89 months), data on long-term success are almost absent. Four cases (2.1%) of secondary aneurysm rupture after embolization owing to endoleak recurrence were reported. All ruptures occurred in aneurysms exceeding initial treatment diameter of 70 mm.

CONCLUSIONS

Initial technical success after liquid embolization for T1EL is high, although long-term clinical success rates are lacking. Within this review, the risk of secondary rupture is comparable with untreated T1EL at 2% with a median follow-up of 13 months, regardless of the initial success of embolization. In general, no decrease in secondary aneurysm rupture after embolization of T1EL after EVAR is demonstrated, although the results of late embolization are debated.

Vogl T, T. Grundmann R. Endovascular and Open Repair of Abdominal Aortic Aneurysm

BACKGROUND

This review presents the surgical indications, surgical procedures, and results in the treatment of asymptomatic and ruptured abdominal aortic aneurysms (AAA).

METHODS

An updated search of the literature on screening, diagnosis, treatment, and follow-up of AAA, based on the German clinical practice guideline published in 2018.

RESULTS

Surgery is indicated in men with an asymptomatic AAA ≥ 5.5 cm and in women, ≥ 5.0 cm. The indication in men is based on four randomized trials, while in women the data are not conclusive. The majority of patients with AAA (around 80%) meanwhile receive endovascular treatment (endovascular aortic repair, EVAR). Open surgery (open aneurysm repair, OAR) is reserved for patients with longer life expectancy and lower morbidity. The pooled 30-day mortality is 1.16% (95% confidence interval [0.92; 1.39]) following EVAR, 3.27% [2.7; 3.83] after OAR. Women have higher operative/interventional mortality than men (odds ratio 1.67%). The mortality for ruptured AAA is extremely high: around 80% of women and 70% of men die after AAA rupture. Ruptured AAA should, if possible, be treated via the endovascular approach, ideally with the patient under local anesthesia. Treatment at specialized centers guarantees the required expertise and infrastructure. Long-term periodic monitoring by mean of imaging (duplex sonography, plus computed tomography if needed) is essential, particularly following EVAR, to detect and (if appropriate) treat endoleaks, to document stable diameter of the eliminated aneurysmal sac, and to determine whether reintervention is necessary (long-term reintervention rate circa 18%).

CONCLUSION

Vascular surgery now offers a high degree of safety in the treatment of patients with asymptomatic AAA. Endovascular intervention is preferred.

Computed Tomography-Aortography Versus Color-Duplex Ultrasound for Surveillance of Endovascular Abdominal Aortic Aneurysm Repair

Background

Color-duplex ultrasonography (DUS) could be an alternative to computed tomography-aortography (CTA) in the lifelong surveillance of patients after endovascular aneurysm repair (EVAR), but there is currently no level 1 evidence. The aim of this study was to assess the diagnostic accuracy of DUS as an alternative to CTA for the follow-up of post-EVAR patients.

Methods

Between December 16, 2010, and June 12, 2015, we conducted a prospective, blinded, diagnostic-accuracy study, in 15 French university hospitals where EVAR was commonly performed. Participants were followed up using both DUS and CTA in a mutually blinded setup until the end of the study or until any major aneurysm-related morphological abnormality requiring reintervention or an amendment to the follow-up policy was revealed by CTA. Database was locked on October 2, 2017. Our main outcome measures were sensitivity, specificity, positive predictive value, negative predictive value, positive and negative likelihood ratios of DUS against reference standard CTA. CIs are binomial 95% CI.

Results

This study recruited prospectively 659 post-EVAR patients of whom 539 (82%) were eligible for further analysis. Following the baseline inclusion visit, 940 additional follow-up visits were performed in the 539 patients. Major aneurysm-related morphological abnormalities were revealed by CTA in 103 patients (17.2/100 person-years [95% CI, 13.9–20.5]). DUS accurately identified 40 patients where a major aneurysm-related morphological abnormality was present (sensitivity, 39% [95% CI, 29–48]) and 403 of 436 patients with negative CTA (specificity, 92% [95% CI, 90–95]). The negative predictive value and positive predictive value of DUS were 92% (95% CI, 90–95) and 39% (95% CI, 27–50), respectively. The positive likelihood ratio was 4.87 (95% CI, 2.9–9.6). DUS sensitivity reached 73% (95% CI, 51–96) in patients requiring an effective reintervention.

Conclusions

DUS had an overall low sensitivity in the follow-up of patients after EVAR, but its performance improved meaningfully when the subset of patients requiring effective reinterventions was considered.

Registration

URL: https://www.clinicaltrials.gov ; Unique identifier: NCT01230203.

Associations of Bariatric Interventions With Micronutrient and Endocrine Disturbances

IMPORTANCE

Few studies have described the longitudinal trajectories of serum levels of micronutrients whose deficiencies are associated with serious sequelae following bariatric procedures, such as anemia, osteoporotic fractures, and neuropathies. Furthermore, previous studies comparing laparoscopic sleeve gastrectomy (LSG) vs Roux-en-Y gastric bypass (LRYGB) or one-anastomosis gastric bypass (OAGB) procedures may have been limited by selection and confounding biases.

OBJECTIVE

To appraise the spectrum and temporal course of micronutrient deficiencies associated with bone metabolism and erythropoiesis after LSG vs OAGB or LRYGB procedures, using the propensity score as a balancing score.

DESIGN, SETTING, AND PARTICIPANTS

This prospective, longitudinal comparative effectiveness study was conducted at a high-volume bariatric unit in Singapore from September 1, 2008, to November 30, 2017, with a cutoff date for analysis of September 2018. Patients who underwent adjustable gastric banding, biliopancreatic diversion procedures, and intragastric balloon procedures were excluded. All other patients who underwent bariatric procedures were included. Data were analyzed from September 23 to 30, 2018.

MAIN OUTCOMES AND MEASURES

Serial assessment of 13 biochemical parameters at 12 time points for up to 5 years after bariatric procedure. Inverse probability-of-treatment weights were used to obtain estimates of the mean associations of variables assessed with the bariatric surgical interventions. Longitudinal trajectories were analyzed using mixed-effects generalized linear models to apportion the temporal variation of serum micronutrients into fixed-effects and random-effects components.

RESULTS

A total of 688 patients were included in this study, of whom 499 underwent LSG (mean [SD] age, 41.5 [11.3] years; 318 [63.7%] women) and 189 underwent OAGB or LRYGB (mean [SD] age, 48.6 [9.4] years; 112 [59.3%] women). There were no differences during follow-up among patients who underwent LSG vs those who underwent OAGB or LRYGB in intact parathyroid hormone levels (mean difference, 7.05 [95% CI, -28.67 to 42.77] pg/mL; P = .70), serum 25-hydroxyvitamin D levels (mean difference, -0.72 [95% CI, -1.56 to 0.12] ng/mL; P = .09), or phosphate levels (mean difference, 0.006 [95% CI, -0.052 to 0.064] mg/dL; P = .83). Hemoglobin levels were a mean 0.63 (95% CI, 0.41 to 0.85) g/dL higher among patients who underwent LSG compared with those who underwent OAGB or LRYGB (P < .001), despite no differences in iron concentration levels (mean difference, 1.50 [95% CI, -1.39 to 4.39] µg/dL; P = .31), total iron-binding capacity (mean difference, 4.36 [95% CI, -5.25 to 13.98] µg/dL; P = .37), or ferritin levels (mean difference, 3.0 [95% CI, -13.0 to 18.9] ng/mL; P = .71). Compared with patients who underwent LSG procedures, patients who underwent OAGB or LRYGB had higher folate levels (mean difference, 2.376 [95% CI, 1.716 to 3.036] ng/mL; P < .001) but lower serum magnesium levels (mean difference, -0.25 [95% CI, -0.35 to -0.16] mg/dL; P < .001) and zinc levels (mean difference, -7.58 [95% CI, -9.92 to -5.24] µg/dL; P < .001).

CONCLUSIONS AND RELEVANCE

These findings suggest that LSG vs OAGB or LRYGB procedures have differential associations with various micronutrient and metabolic parameters. These differences should be recognized in guidelines for postbariatric nutritional surveillance and prevention.

Expression Patterns of Circulating MicroRNAs in the Risk Stratification of Bicuspid Aortopathy

Objective: Aortic size-based criteria are of limited value in the prediction of aortic events, while most aortic events occur in patients with proximal aortic diameters < 50 mm. Serological biomarkers and especially circulating microRNAs (miRNAs) have been proposed as an elegant tool to improve risk stratification in patients with different aortopathies. Therefore, we aimed to evaluate the levels of circulating miRNAs in a surgical cohort of patients presenting with bicuspid aortic valve disease and distinct valvulo-aortic phenotypes. Methods: We prospectively examined a consecutive cohort of 145 patients referred for aortic valve surgery: (1) Sixty three patients (mean age 47 ± 11 years, 92% male) with bicuspid aortic valve regurgitation and root dilatation (BAV-AR), (2) thirty two patients (mean age 59 ± 11 years, 73% male) with bicuspid aortic valve stenosis (BAV-AS), and (3) fifty patients (mean age 56 ± 14 years, 55% male) with tricuspid aortic valve stenosis and normal aortic root diameters (TAV-AS) who underwent aortic valve+/-proximal aortic surgery at a single institution. MicroRNAs analysis included 11 miRNAs, all published previously in association with aortopathies. Endpoints of our study were (1) correlation between circulating miRNAs and aortic diameter and (2) comparison of circulating miRNAs in distinct valvulo-aortic phenotypes. Results: We found a significant inverse linear correlation between circulating miRNAs levels and proximal aortic diameter in the whole study cohort. The strongest correlation was found for miR-17 (r = −0.42, p < 0.001), miR-20a (r = −0.37, p < 0.001), and miR-106a (r = −0.32, p < 0.001). All miRNAs were significantly downregulated in BAV vs. TAV with normal aortic root dimensions Conclusions: Our data demonstrate a significant inverse correlation between circulating miRNAs levels and the maximal aortic diameter in BAV aortopathy. When comparing miRNAs expression patterns in BAV vs. TAV patients with normal aortic root dimensions, BAV patients showed significant downregulation of analyzed miRNAs as compared to their TAV counterparts. Further multicenter studies in larger cohorts are needed to further validate these results.

Harnessing repeated measurements of predictor variables for clinical risk prediction: a review of existing methods

BACKGROUND

Clinical prediction models (CPMs) predict the risk of health outcomes for individual patients. The majority of existing CPMs only harness cross-sectional patient information. Incorporating repeated measurements, such as those stored in electronic health records, into CPMs may provide an opportunity to enhance their performance. However, the number and complexity of methodological approaches available could make it difficult for researchers to explore this opportunity. Our objective was to review the literature and summarise existing approaches for harnessing repeated measurements of predictor variables in CPMs, primarily to make this field more accessible for applied researchers.

METHODS

MEDLINE, Embase and Web of Science were searched for articles reporting the development of a multivariable CPM for individual-level prediction of future binary or time-to-event outcomes and modelling repeated measurements of at least one predictor. Information was extracted on the following: the methodology used, its specific aim, reported advantages and limitations, and software available to apply the method.

RESULTS

The search revealed 217 relevant articles. Seven methodological frameworks were identified: time-dependent covariate modelling, generalised estimating equations, landmark analysis, two-stage modelling, joint-modelling, trajectory classification and machine learning. Each of these frameworks satisfies at least one of three aims: to better represent the predictor-outcome relationship over time, to infer a covariate value at a pre-specified time and to account for the effect of covariate change.

CONCLUSIONS

The applicability of identified methods depends on the motivation for including longitudinal information and the method's compatibility with the clinical context and available patient data, for both model development and risk estimation in practice.

Abdominal aortic aneurysm in prostate cancer patients: the "road map" from incidental detection to advanced predictive, preventive, and personalized approach utilizing common follow-up for both pathologies

Abdominal aortic aneurysm (AAA) is often a hidden pathological process showing no clinical symptoms. Genetic burden, smoking, male gender, age > 65 years, and white race have been identified as the main risk factors. A regular screening program has been introduced but is, as yet, unclear and is not performed in most countries. Prostate cancer is the most frequent male malignant disease in Western countries. Prostate cancer is a disease of older age with a median primary diagnosis of over 60 years. In recent years, advanced imaging methods have been established as important diagnostic tools in prostate cancer diagnostics. The incidental detection of AAA during diagnostic imaging performed due to prostate cancer diagnosis could reveal some asymptomatic aneurysms. Using our experience, the incidental detection of AAA during 18F-fluoromethylcholine PET/CT imaging, performed due to the staging, follow-up, and restaging of the prostate cancer, was reworked into a regular tool of secondary prevention within the framework of personalized medicine strategies. Experience with this type of AAA detection is demonstrated by a cohort of 500 patients who underwent 18F-fluorometylcholine PET/CT examination due to the staging or restaging of prostate cancer. A total of 28 aneurysms were detected (26 aneurysms < 50 mm, 2 aneurysms > 50 mm). In 2 cases (diameter < 50 mm), serious complications were found (penetrating aortic ulcer). The detection and monitoring of AAA in patients undergoing 18F-fluorometylcholine PET/CT due to the prostate cancer offers the possibility of a secondary prevention of AAA, patient stratification, and common follow-up for both pathologies.

Optimizing Surveillance and Re-intervention Strategy Following Elective Endovascular Repair of Abdominal Aortic Aneurysms

BACKGROUND

EVAR for abdominal aortic aneurysm has an initial survival advantage over OR, but more frequent complications increase costs and long-term aneurysm-related mortality. Randomized controlled trials of EVAR versus OR have shown EVAR is not cost-effective over a patient's lifetime. However, in the EVAR-1 trial, postoperative surveillance may have been sub-optimal, as the importance of sac growth as a predictor of graft failure was overlooked.

METHODS

Real-world data informed a discrete event simulation model of postoperative outcomes following EVAR. Outcomes observed EVAR-1 were compared with those from 5 alternative postoperative surveillance and re-intervention strategies. Key events, quality-adjusted life years and costs were predicted. The impact of using complication and rupture rates from more recent devices, imaging and re-intervention methods was also explored.

RESULTS

Compared with observed EVAR-1 outcomes, modeling full adherence to the EVAR-1 scan protocol reduced abdominal aortic aneurysm (AAA) deaths by 3% and increased elective re-interventions by 44%. European Society re-intervention guidelines provided the most clinically effective strategy, with an 8% reduction in AAA deaths, but a 52% increase in elective re-interventions. The cheapest and most cost-effective strategy used lifetime annual ultrasound in primary care with confirmatory computed tomography if necessary, and reduced AAA-related deaths by 5%. Using contemporary rates for complications and rupture did not alter these conclusions.

CONCLUSIONS

All alternative strategies improved clinical benefits compared with the EVAR-1 trial. Further work is needed regarding the cost and accuracy of primary care ultrasound, and the potential impact of these strategies in the comparison with OR.

Five-year reintervention after endovascular abdominal aortic aneurysm repair in the Vascular Quality Initiative

OBJECTIVE

Patients who undergo endovascular abdominal aortic aneurysm repair (EVR) remain at risk for reintervention and rupture. We sought to define the 5-year rate of reintervention and rupture after EVR in the Vascular Quality Initiative (VQI).

METHODS

We identified all patients in the VQI who underwent EVR from 2003 to 2015. We linked patients in the VQI to Medicare claims for long-term outcomes. We stratified patients on baseline clinical and procedural characteristics to identify those at risk for reintervention. Our primary outcomes were 5-year rates of reintervention and late aneurysm rupture after EVR. We assessed these with Kaplan-Meier survival estimation.

RESULTS

We studied 12,911 patients who underwent EVR. The mean age was 75.5 years, 79.9% were male, 3.9% were black, and 89.1% of operations were performed electively. The 5-year rate of reintervention for the entire cohort was 21%, and the 5-year rate of late aneurysm rupture was 3%. Reintervention rates varied across categories of EVR urgency. Patients who underwent EVR electively had the lowest 5-year rate of reintervention at 20%. Those who underwent surgery for symptomatic aneurysms had higher rates of reintervention at 25%. Patients undergoing EVR emergently for rupture had the highest rate of reintervention, 27% at 4 years (log-rank across the three groups, P < .001). Black race and aneurysm size of 6.0 cm or greater were associated with significantly elevated reintervention rates (black, 31% vs white, 20% [log-rank, P < .001]; aneurysm size 6.0 cm or greater, 27% vs all others, <20% [log-rank, P < .001]). There were no significant associations between age or gender and the 5-year rate of reintervention.

CONCLUSIONS

More than one in five Medicare patients undergo reintervention within 5 years after EVR in the VQI; late rupture remains low at 3%. Black patients, those with large aneurysms, and those who undergo EVR urgently and emergently have a higher likelihood of adverse outcomes and should be the focus of diligent long-term surveillance.