Activated clotting time-guided heparinization during open AAA surgery: a pilot study

BACKGROUND

Arterial thrombo-embolic complications (TEC) are still common during and after non-cardiac arterial procedures (NCAP). While unfractionated heparin has been used during NCAP for more than 70 years to prevent TEC, there is no consensus regarding the optimal dosing strategy. The aim of this pilot study was to test the effectiveness and feasibility of an activated clotting time (ACT)-guided heparinization protocol during open abdominal aortic aneurysm (AAA) surgery, in anticipation of a randomized controlled trial (RCT) investigating if ACT-guided heparinization leads to better clinical outcomes compared to a single bolus of 5000 IU of heparin.

METHODS

A prospective multicentre pilot study was performed. All patients undergoing elective open repair for an AAA (distal of the superior mesenteric artery) between March 2017 and January 2020 were included. Two heparin dosage protocols were compared: ACT-guided heparinization with an initial dose of 100 IU/kg versus a bolus of 5000 IU. The primary outcome was the effectiveness and feasibility of an ACT-guided heparinization protocol with an initial heparin dose of 100 IU/kg during open AAA surgery. Bleeding complications, TEC, and mortality were investigated for safety purposes.

RESULTS

A total of 50 patients were included in the current study. Eighteen patients received a single dose of 5000 IU of heparin and 32 patients received 100 IU/kg of heparin with additional doses based on the ACT. All patients who received the 100 IU/kg dosing protocol reached the target ACT of > 200 s. In the 5000 IU group, TEC occurred in three patients (17%), versus three patients (9.4%) in the 100 IU/kg group. Bleeding complications were found in six patients (33%) in the 5000 IU group and in 9 patients (28%) in the 100 IU/kg group. No mortality occurred in either group.

CONCLUSIONS

This pilot study demonstrated that ACT-guided heparinization with an initial dose of 100 IU/kg appears to be feasible and leads to adequate anticoagulation levels. Further randomized studies seem feasible and warranted to determine whether ACT-guided heparinization results in better outcomes after open AAA repair.

Expanding the clinical spectrum of biglycan-related Meester-Loeys syndrome

Pathogenic loss-of-function variants in BGN, an X-linked gene encoding biglycan, are associated with Meester-Loeys syndrome (MRLS), a thoracic aortic aneurysm/dissection syndrome. Since the initial publication of five probands in 2017, we have considerably expanded our MRLS cohort to a total of 18 probands (16 males and 2 females). Segregation analyses identified 36 additional BGN variant-harboring family members (9 males and 27 females). The identified BGN variants were shown to lead to loss-of-function by cDNA and Western Blot analyses of skin fibroblasts or were strongly predicted to lead to loss-of-function based on the nature of the variant. No (likely) pathogenic missense variants without additional (predicted) splice effects were identified. Interestingly, a male proband with a deletion spanning the coding sequence of BGN and the 5' untranslated region of the downstream gene (ATP2B3) presented with a more severe skeletal phenotype. This may possibly be explained by expressional activation of the downstream ATPase ATP2B3 (normally repressed in skin fibroblasts) driven by the remnant BGN promotor. This study highlights that aneurysms and dissections in MRLS extend beyond the thoracic aorta, affecting the entire arterial tree, and cardiovascular symptoms may coincide with non-specific connective tissue features. Furthermore, the clinical presentation is more severe and penetrant in males compared to females. Extensive analysis at RNA, cDNA, and/or protein level is recommended to prove a loss-of-function effect before determining the pathogenicity of identified BGN missense and non-canonical splice variants. In conclusion, distinct mechanisms may underlie the wide phenotypic spectrum of MRLS patients carrying loss-of-function variants in BGN.

Endovascular Repair of Juxtarenal and Pararenal Abdominal Aortic Aneurysms Using a Novel Low-Profile Fenestrated Custom-Made Endograft: Technical Details and Short-Term Outcomes

INTRODUCTION

The aim of this study is to share preliminary experiences and outcomes with a novel custom-made fenestrated TREO® Abdominal Stent-Graft System to treat juxtarenal and pararenal abdominal aortic aneurysms (AAAs).

METHODS

Juxtarenal and pararenal AAA patients treated with the custom-made fenestrated TREO® Abdominal Stent-Graft System were included from 4 high-volume European academic medical centers from June 2021 to September 2023. Technical success and 30-day/in-hospital mortality and complications were analyzed. Technical success was defined as successful endovascular implantation of the stent graft with preservation of antegrade flow to the target vessels, and absence of type 1 or 2 endoleak (EL) at the first postoperative computed tomography angiography (CTA).

RESULTS

Forty-two consecutive patients were included. The majority of the devices were constructed with 2 (N=4; 9.5%), 3 (N=9; 21.4%), or 4 (N=27; 64%) fenestrations. In 1 case, the device was constructed with a single fenestration (2.4%) and 1 device contained 5 fenestrations (2.4%); 17% had previous AAA repair. Target vessel cannulation with placement of a bridging stent was successful in all but 1 vessel (99, 3%). One aneurysm-related death occurred in the direct postoperative period and 2 limb occlusions necessitated reintervention during admission. In the median follow-up period of 101 (2-620) days, 3 more patients died due to non-aneurysm-related causes. Technical success was achieved in 90% of the cases. Nineteen ELs were seen on the first postoperative CT scan: 1 type 1b EL (N=1; 2%), 15 type 2 ELs (N=15; 36%), and 3 type 3 ELs (N=3%). Eleven patients received more than 1 CT scan during a median follow-up of 361 days (82-620): 3 type 2 ELs resolved and 1 type 3 EL was treated in this period. In the follow-up, 1 patient had a coagulation disorder that caused occlusions of the branches.

CONCLUSION

The results of the first experiences using the custom-made fenestrated TREO® Abdominal Stent-Graft System in Europe are promising. There was a low short-term mortality and morbidity rate in these patients of which 17% had previous AAA repair. Mid-term and long-term follow-up data are needed to evaluate endograft durability and performance.

CLINICAL IMPACT

This study shows the first experiences and short-term results of a novel low-profile custom-made device: the custom-made fenestrated TREO® Abdominal Stent-Graft System. Showing these results and experiences can help the physicians in clinical decision-making for their patients.

Prevalence of type II endoleak after elective endovascular aneurysm repair with polytetrafluoroethylene- or polyester-based endografts

OBJECTIVE

Type II endoleak is the most frequent complication after endovascular abdominal aneurysm repair. Polytetrafluoroethylene and polyester (PE) are the two most commonly used graft materials in endovascular aneurysm repair (EVAR) devices. Biological properties of the material might influence the appearance and persistence of type II endoleak (T2EL). Therefore, the aim of this study was to evaluate potential differences in the prevalence of T2EL after EVAR between polytetrafluoroethylene (PTFE) and PE endografts in patients electively treated for an infrarenal abdominal aortic aneurysm.

METHODS

A single-center, retrospective, observational study was conducted between January 2011 and January 2022. Preoperative, procedural, and follow-up data were derived from electronic health records. Imaging included computed tomography scans, and/or duplex ultrasound examination. The primary end point was the prevalence of T2EL diagnosed within 1 year after EVAR. Secondary end points included the prevalence of T2EL throughout follow-up, early (≤30 days) and late (>30 days) T2EL, the rate of T2EL disappearance during the follow-up period, the prevalence of type I and III endoleak, and T2EL-related reinterventions.

RESULTS

Follow-up was available for 394 patients, 245 in the PE and 149 in the PTFE group. The prevalence of T2EL diagnosed within 1 year after endovascular repair was 11.8% in the PE group and 21.5% in the PTFE group (P = .010). There was no significant difference in early (≤30 days) and late (>30 days) T2EL between groups (P = .270 and P = .311). There was no difference in the freedom from endoleak type II reinterventions between groups (P = .877).

CONCLUSIONS

The prevalence of T2EL after elective EVAR is significantly higher with the use of PTFE-based endografts compared with PE-based endografts. This difference is mostly based on T2EL diagnosed after 30 days of follow-up.

The Additional Value of Activated Clotting Time-Guided Heparinization During Interventions for Peripheral Arterial Disease

PURPOSE

Unfractionated heparin is widely used to lower the risk of arterial thromboembolic complications (ATECs) during interventions for peripheral arterial disease (PAD), but it is still unknown which heparin dose is the safest in terms of preventing ATECs and bleeding complications. This study aims to evaluate the incidence of complications during interventions for PAD and the relation between this incidence and different heparinization protocols.

MATERIALS AND METHODS

A retrospective analysis of a prospective multicenter cohort study was performed. Between June 2015 and September 2022, 355 patients who underwent peripheral interventions for PAD were included. All patients who were included before July 2018 received 5000 international units (IU) of heparin (group 1). Starting from July 2018, all included patients received an initial dose of 100 IU/kg, with potential additional heparin doses based on activated clotting time (ACT) values (group 2). Data on ACT values and complications within 30 days post-procedurally were collected.

RESULTS

In total, 24 ATECs and 48 bleeding complications occurred. In group 1, 8.7% (n=11) of patients suffered from ATEC, compared with 5.7% (n=13) in group 2. Thirteen percent of patients (n=17) in group 1 had a bleeding complication, compared with 14% (n=31) in group 2. Arterial thromboembolic complications were more often found in patients with peak ACT values of <200 seconds, compared with ACT values between 200 and 250 seconds, 15% (n=6) versus 5.9% (n=9), respectively, p=0.048. Patients with peak ACT values >250 seconds had a higher incidence of bleeding complications compared with an ACT between 200 and 250 seconds, 24% (n=21) versus 9.8% (n=15), respectively, p=0.003. Forty-four percent of patients (n=23) in group 1 reached a peak ACT of >200 seconds, compared with 95% (n=218) of patients in group 2 (p=0.001).

CONCLUSION

ATEC was found in 6.8% (n=24) and bleeding complications in 14% (n=48) of patients who underwent a procedure for PAD. There was a significantly higher incidence of ATECs in patients with a peak ACT value <200 seconds, and a higher incidence of bleeding complications in patients with a peak ACT value >250 seconds. The findings obtained from this study may serve as a basis for conducting future research on heparinization during procedures for PAD, with a larger sample size.

CLINICAL IMPACT

Heparin is administered during arterial interventions for peripheral arterial disease (PAD) to decrease the risk of arterial (thrombo)embolic complications (ATEC) during or shortly following surgery. The effect of heparin is unpredictable in the individual patient, and the optimal dosage of this anticoagulant has not yet been established. Using the activated clotting time (ACT), the anticoagulatory effect of heparin can be monitored periprocedurally. Previous research on the incidence of both ATEC and bleeding complications, or on the optimal dosage of heparin administration, is scarce. This study aims to investigate the incidence of ATEC and bleeding complications between 2 different dosage protocols of heparin-a standard bolus of 5000 IU or ACT-guided heparinization-and thereby provide clarity on the optimal dose of heparin during peripheral arterial interventions for PAD.

The Effect of Smoking on the Activated Clotting Time and the Incidence of Complications in Noncardiac Arterial Procedures

PURPOSE

Smoking is a well-known risk factor for developing arterial diseases and for an increase of complications during and after vascular procedures. Although smoking has a proven effect on hemostasis, no literature is available on the effect of smoking on the activated clotting time (ACT), which is used to monitor the effect of heparin during noncardiac arterial procedures (NCAP). The aim of this study was to examine the effect of smoking on ACT values and the incidence of complications during the same admission or 30 day follow-up of NCAP.

MATERIALS AND METHODS

A post hoc analysis of a prospective multicenter cohort study was performed. Patients older than 18 years, who underwent NCAP between December 2016 and April 2021, were enrolled. Patients were divided into 2 groups based on smoking status: never/former smokers and current smokers. Two heparin dosing protocols were used: an initial bolus of 5000 IU or 100 IU/kg bodyweight.

RESULTS

In total, 773 patients met the inclusion criteria. Five minutes after administration of 5000 IU of heparin, mean ACT values were 190 and 196 seconds for nonsmokers and smokers, respectively (p=0.078). After 100 IU/kg of heparin, mean ACT values were 229 and 226 seconds for nonsmokers and smokers, respectively (p=0.37). Incidence of complications in the whole study cohort was not significantly different for nonsmokers compared with smokers (arterial thrombo-embolic complication [ATEC] 4.7% vs 5.7% p=0.55; hemorrhagic complications 15% vs 18% p=0.29). In subgroup-analysis, a significant difference between smoking groups was found for hemorrhagic complications after open aneurysm repair (p=0.024). However, after adjusting for confounders, the difference between the smoking groups annulled.

CONCLUSION

The results of this study suggest that smoking does not have a significant effect on ACT values or on the incidence of complications in NCAP. Large-scale studies are required to further analyze potential factors having an effect on the ACT and perioperative and postoperative complications, which could help individualize heparinization strategy.

CLINICAL IMPACT

There is high variance between patients in their response on administration of heparin, this is not yet fully understood. This study investigated the effect of smoking in a large prospective multicentre cohort. The results suggests that active smoking does not have an effect on the activated clotting time after administration of heparin. Also no significant effect of smoking could be found on the incidence of all registered complications. Monitoring of the effect of heparin remains important to provide patients with safe anticoagulation during vascular procedures.

Unfractionated heparin and the activated clotting time in non-cardiac arterial procedures

INTRODUCTION

Unfractionated heparin is administered during non-cardiac arterial procedures (NCAP) to prevent thromboembolic complications. In order to achieve a safe level of anticoagulation, the effect of heparin can be measured. The aim of this review was to provide an overview on what is known about heparin, suggested tests to monitor the effect of heparin, including the activated clotting time (ACT), and the factors that could influence that ACT.

EVIDENCE ACQUISITION

A literature search in PubMed was performed. Articles reporting on heparin, clotting time tests (including thrombin time, activated partial thromboplastin time, anti-activated factor X and ACT), and ACT measurement devices were selected.

EVIDENCE SYNTHESIS

Heparin has a non-predictable effect in the individual patient, which could be measured using the ACT. However, ACT values can be influenced by many factors, such as hemodilution, hypothermia and thrombocytopenia. In addition, a high variation in ACT outcomes is found between measurement devices of different brands. In the sparse literature on the role of ACT during NCAP, no consensus has been reached on optimal target ACT values. An ACT >250 seconds leads to more bleeding complications. Females have a longer ACT after heparin administration, with a higher risk of bleeding complications.

CONCLUSIONS

The effect of heparin is unpredictable. ACT can be used to monitor the effect of heparin and achieve individualized anticoagulation, tailored to the patient and the specifics of the operative procedure. However, the ACT itself can be affected by several factors and caution must be present, as measured ACT values differ between measurement devices.

Perprocedural Heparinization in Non-cardiac Arterial Procedures: The Current Practice in the Netherlands

PURPOSE

Heparin is the most widely-used anticoagulant to prevent thrombo-embolic complications during non-cardiac arterial procedures (NCAP). Unfortunately, there is a lack of evidence and consequently non-uniformity in guidelines on perprocedural heparin management. Detailed insight into the current practice of antithrombotic strategies during NCAP in the Netherlands is important, aiming to identify potential optimal protocols and local differences concerning perprocedural heparinization.

MATERIALS AND METHODS

A comprehensive online survey was distributed electronically to vascular surgeons of every hospital in the Netherlands in which NCAP were performed. Data were collected from September 2020 to October 2021.

RESULTS

The response rate was 90% (53/59 hospitals). During NCAP, all surgeons generally administered heparin before arterial clamping. In 74% (39/54) of hospitals, a single heparin dosing protocol was used for all types of patients and vascular procedures. In 40%, there was no uniformity in heparin dosing between vascular surgeons. Depending on the procedure, a fixed bolus heparin, predominantly 5000 IU, was administered in 73% to 93%. In the remaining hospitals (7%-27%), a bodyweight-based heparin protocol was used, with an initial dose of 70 or 100 IU/kg. A minority (28%) monitored the effect of heparin in patients using the activated clotting time add (ACT) after activated clotting time. Target values varied between 180 and 250 seconds or 2 times the baseline ACT.

CONCLUSION

This survey demonstrates considerable variability in perprocedural heparinization during NCAP in the Netherlands. Future research on heparin dosing is needed to harmonize and optimize heparin dosage protocols and contemporary guidelines during NCAP, and thereby improve vascular surgical care and patient safety.

CLINICAL IMPACT

This survey demonstrated persisting intra- and inter-hospital variability in perprocedural heparinization during non-cardiac arterial procedures (NCAP) in the Netherlands. The observed variability in heparinization strategies highlights the need for high quality evidence on perprocedural anticoagulation strategies. This is needed in order to harmonize and optimize heparin dosage protocols and contemporary guidelines and thereby improve vascular surgical patient care. Based on the current results, an international survey will be conducted by the authors to gain additional insight into the antithrombotic strategies used during NCAP, aiming to harmonize anticoagulation protocols worldwide.

Editor's Choice - Sex Differences in Response to Administration of Heparin During Non-Cardiac Arterial Procedures

OBJECTIVE

Females are more prone to complications during non-cardiac arterial procedures (NCAPs) than males. The current study investigated the difference in the effect of peri-procedural prophylactic heparin in males and females, using the activated clotting time (ACT). This was a retrospective analysis of a prospective multicentre cohort study.

METHODS

All patients undergoing elective NCAP using heparin and ACT measurements between January 2016 and March 2020 were included. Two heparin dosage protocols were used: weight based dosing of 100 IU/kg (international units per kilogram) or a bolus of 5 000 IU. The primary outcome was the anticoagulatory effect of heparin after five minutes, measured by ACT. Secondary outcomes were the effect of heparin after 30 minutes, bleeding complications, and arterial thromboembolic complications (ATECs).

RESULTS

A total of 778 patients were included; 26% were female. After 100 IU/kg (n = 300), females more often reached longer ACT (< 200 seconds: 22% vs. 25%, p = .62; 200 - 250 seconds: 41% vs. 53%, p = .058; 251 - 280 seconds, 26% vs. 15%, p = .030). The mean ACT after 100 IU/kg heparin was 233 seconds (95% confidence interval [CI] 224 - 243) for females and 226 seconds (95% CI 221 - 231) for males (p = .057). After a bolus of 5 000 IU of heparin (n = 411), females reached significantly higher levels of anticoagulation than males (mean ACT 204 seconds vs. 190 seconds: p ≤ .001; ACT < 200 seconds: 44% vs. 66%; p < .001; ACT 200 - 250 seconds: 47% vs. 30%, p = .001; ACT 251 - 280 seconds: 7.8% vs. 2.3%, p = .009). Thirty minutes after heparin administration, 58% of all patients had an ACT < 200 seconds. ATECs did not differ between females and males (6.9% vs. 5.1%, p = .33) but bleeding complications were higher in females (27% vs. 16%, p = .001).

CONCLUSION

Heparin leads to significantly longer ACT in females during NCAP. Further research is needed to investigate whether individually based heparin protocols lead to fewer bleeding complications and lower incidence of ATECs.

Long-term age-stratified survival following endovascular and open abdominal aortic aneurysm repair

OBJECTIVE

The long-term survival differences between endovascular and open repair for abdominal aortic aneurysms and specifically the impact of age on these differences remain a topic of debate. Therefore, we compared the long-term mortality between endovascular and open abdominal aneurysm repair for patients of different ages.

METHODS

This was a retrospective cohort study of prospectively collected data from patients undergoing elective endovascular or open repair for infrarenal abdominal aortic aneurysms within the Vascular Quality Initiative multi-national clinical registry (2003-2021). The primary outcome was long-term all-cause mortality comparing endovascular and open repair for patients aged <65 years, between 65-79 years, and those aged ≥80. In addition, we investigated the interaction between repair modality and ten-year hazard of mortality for sex, aneurysm diameter, and several pre-operative comorbid conditions within each age category. To account for non-random assignment of treatment, we used propensity scores and inverse probability weighted Cox proportional hazard analysis.

RESULTS

We identified 48,074 patients undergoing elective infrarenal abdominal aneurysm repair (89% endovascular) within the study period, including 7,940 patients aged <65, 29,555 aged between 65-79, and 10,579 aged ≥80 years. EVAR was associated with a higher propensity score-adjusted long-term hazard of mortality compared to open repair in the cohort aged <65 years (hazard ratio [HR]: 1.39; 95% confidence interval [CI]: 1.04-1.86; P=.026). The mortality was similar in the age cohort between 65-79 (HR: 0.94; 95%CI: 0.79-1.10; P=.43), while EVAR was associated with a lower hazard of mortality in the cohort aged ≥80 years (HR: 0.63; 95%CI: 0.46-0.86; P=.004). In patients aged <65, the hazard of mortality was higher with endovascular compared with open repair in those with female sex (HR: 4.40; 95%CI: 1.75-11.0), an aneurysm diameter >65mm (HR: 2.19; 95%CI: 1.11-4.34), and absence of coronary artery disease (HR: 1.26; 95%CI: 0.83-1.91), congestive heart failure (HR: 1.41; 95%CI: 1.03-1.92), and renal dysfunction (HR: 1.46; 95%CI: 1.04-2.05). In the patient cohort aged ≥80, a lower hazard of mortality for endovascular vs. open repair was observed for male patients, or those with small aneurysms or certain comorbidities.

CONCLUSIONS

In a selected group of young patients with a substantial life expectancy, the long-term mortality is higher with endovascular compared to open repair for infrarenal abdominal aortic aneurysms. Long-term mortality with endovascular repair is similar in the middle cohort and lower in the elderly cohort compared to open repair.

Intragraft Obstructive Thrombus Two Years After Endovascular Repair of Traumatic Aortic Injury: A Case Report and Review of the Literature

Introduction

Thoracic endovascular aortic repair (TEVAR) is the treatment of choice for blunt thoracic aortic injury (BTAI) and has proven to be a good alternative to open surgery. TEVAR requires less operation time, has fewer complications, can be used for relatively unstable patients, and is associated with a significantly lower mortality rate. Moreover, long term follow up data demonstrate low re-intervention rates and stentgraft failure.

Report

The case of a 21 year old man who sustained severe trauma, including a traumatic pseudoaneurysm of the descending thoracic aorta distal to the left subclavian artery in 2016, is presented. The patient was treated by TEVAR. Two years later, he presented with progressive paraplegia due to stentgraft occlusion occurring four days after a new high velocity motor vehicle accident. An axillofemoral bypass was performed to assure blood flow to the lower body. Two days later the stentgraft was removed via left thoracotomy and replaced by a Dacron graft. Gross examination showed severe thrombus formation at the proximal edge, and a thrombotic occlusion in the middle and distal third of the stent. After three months of hospitalisation the patient was discharged to a rehabilitation clinic with partial recovery of his paraplegia. As of June 2020, the patient was able to walk without assistance and his paraplegia improved with only loss of sensation of his lower legs.

Conclusion

A serious thrombotic complication two years after TEVAR is described. Although TEVAR is the currently preferred treatment for BTAI, more research is needed to examine the mechanisms behind this thrombotic complication and to elucidate whether TEVAR is definitive treatment or a “bridge to further surgery”. Smaller diameter stentgrafts, anticoagulation, regular (lifelong) follow up imaging, and prophylactic surgical conversion in (selected) patients might help to prevent this serious complication.

•

Although thoracic endovascular aortic repair is the first choice treatment for blunt thoracic aortic injury, the cause of intragraft thrombus is unknown.

•

Nine cases have been reported with thrombotic (near) occlusions of thoracic stentgrafts. This is the first reported total occlusion following a second trauma.

•

Oversizing and trauma can potentially play a role in the formation and progression of obstructive thrombus in thoracic stentgrafts.

•

Follow up is important to detect intragraft thrombus deposition and to prevent major complications by adjusting anticoagulation or performing prophylactic removal of thrombotic stentgrafts.

ACTION-1: study protocol for a randomised controlled trial on ACT-guided heparinization during open abdominal aortic aneurysm repair

BACKGROUND

Heparin is used worldwide for 70 years during all non-cardiac arterial procedures (NCAP) to reduce thrombo-embolic complications (TEC). But heparin also increases blood loss causing possible harm for the patient. Heparin has an unpredictable effect in the individual patient. The activated clotting time (ACT) can measure the effect of heparin. Currently, this ACT is not measured during NCAP as the standard of care, contrary to during cardiac interventions, open and endovascular. A RCT will evaluate if ACT-guided heparinization results in less TEC than the current standard: a single bolus of 5000 IU of heparin and no measurements at all. A goal ACT of 200-220 s should be reached during ACT-guided heparinization and this should decrease (mortality caused by) TEC, while not increasing major bleeding complications. This RCT will be executed during open abdominal aortic aneurysm (AAA) surgery, as this is a standardized procedure throughout Europe.

METHODS

Seven hundred fifty patients, who will undergo open AAA repair of an aneurysm originating below the superior mesenteric artery, will be randomised in 2 treatment arms: 5000 IU of heparin and no ACT measurements and no additional doses of heparin, or a protocol of 100 IU/kg bolus of heparin and ACT measurements after 5 min, and then every 30 min. The goal ACT is 200-220 s. If the ACT after 5 min is < 180 s, 60 IU/kg will be administered; if the ACT is between 180 and 200 s, 30 IU/kg. If the ACT is > 220 s, no extra heparin is given, and the ACT is measured after 30 min and then the same protocol is applied. The expected incidence for the combined endpoint of TEC and mortality is 19% for the 5000 IU group and 11% for the ACT-guided group.

DISCUSSION

The ACTION-1 trial is an international RCT during open AAA surgery, designed to show superiority of ACT-guided heparinization compared to the current standard of a single bolus of 5000 IU of heparin. A significant reduction in TEC and mortality, without more major bleeding complications, must be proven with a relevant economic benefit. TRIAL REGISTRATION {2A}: NTR NL8421 ClinicalTrials.gov NCT04061798 . Registered on 20 August 2019 EudraCT 2018-003393-27 TRIAL REGISTRATION: DATA SET {2B}: Data category Information Primary registry and trial identifying number ClinicalTrials.gov : NCT04061798 Date of registration in primary registry 20-08-2019 Secondary identifying numbers NTR: NL8421 EudraCT: 2018-003393-27 Source(s) of monetary or material support ZonMw: The Netherlands Organisation for Health Research and Development Dijklander Ziekenhuis Amsterdam UMC Primary sponsor Dijklander Ziekenhuis Secondary sponsor(s) N/A Contact for public queries A.M. Wiersema, MD, PhD Arno@wiersema.nu 0031-229 208 206 Contact for scientific queries A.M. Wiersema, MD, PhD Arno@wiersema.nu 0031-229 208 206 Public title ACT Guided Heparinization During Open Abdominal Aortic Aneurysm Repair (ACTION-1) Scientific title ACTION-1: ACT Guided Heparinization During Open Abdominal Aortic Aneurysm Repair, a Randomised Trial Countries of recruitment The Netherlands. Soon the recruitment will start in Germany Health condition(s) or problem(s) studied Abdominal aortic aneurysm, arterial disease, surgery Intervention(s) ACT-guided heparinization 5000 IU of heparin Key inclusion and exclusion criteria Ages eligible for the study: ≥18 years Sexes eligible for the study: both Accepts healthy volunteers: no Inclusion criteria: Study type Interventional Allocation: randomized Intervention model: parallel assignment Masking: single blind (patient) Primary purpose: treatment Phase IV Date of first enrolment March 2020 Target sample size 750 Recruitment status Recruiting Primary outcome(s) The primary efficacy endpoint is 30-day mortality and in-hospital mortality during the same admission. The primary safety endpoint is the incidence of bleeding complications according to E-CABG classification, grade 1 and higher. Key secondary outcomes Serious complications as depicted in the Suggested Standards for Reports on Aneurysmal disease: all complications requiring re-operation, longer hospital stay, all complications.

Results from a nationwide prospective registry on open surgical or endovascular repair of juxtarenal abdominal aortic aneurysms

BACKGROUND

Juxtarenal abdominal aortic aneurysms (JRAAA) can be treated either with open surgical repair (OSR) including suprarenal clamping or by complex endovascular aneurysm repair (cEVAR). In this study we present the comparison between the short-term mortality and complications of the elective JRAAA treatment modalities from a national database reflecting daily practice in the Netherlands.

METHODS

All patients undergoing elective JRAAA open repair or cEVAR (fenestrated EVAR or chimney EVAR) between January 2016 and December 2018 registered in the Dutch Surgical Aneurysm Audit (DSAA) were eligible for inclusion. Descriptive perioperative variables and outcomes were compared between patients treated with open surgery or endovascularly. Adjusted odds ratios for short-term outcomes were calculated by logistic regression analysis.

RESULTS

In all, 455 primary treated JRAAA patients could be included (258 OSR, 197 cEVAR). Younger patients and female patients were treated more often with OSR vs cEVAR (72±6.1 vs. 76±6.0, p<0.001, 22% vs 15%, p=0.047, respectively). Patients treated with OSR had significantly more major and minor complications as well as a higher chance of early mortality (OSR: cEVAR, 45% vs. 21%, p<0.001; 34% vs. 23%, p =0.011; 6.6% vs. 2.5%, p=0.046, respectively). After logistic regression with adjustment for confounders, patients who were treated with OSR showed an odds ratio of 3.64 (95%CI 2.25-5.89, p<0.001) for major complications compared to patients treated with cEVAR and for minor complications the odds ratios were 2.17 (95%CI 1.34-3.53, p=0.002) higher. For early mortality the odds ratios were 3.79 (95%CI 1.26-11.34, p=0.017) higher after OSR compared to cEVAR.

CONCLUSION

In this study, after primary elective OSR for JRAAA the odds for major complications, minor complications, and short-term mortality were significantly higher compared to cEVAR.

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.

Patient-Specific 3-Dimensional Model of Smooth Muscle Cell and Extracellular Matrix Dysfunction for the Study of Aortic Aneurysms

INTRODUCTION

Abdominal aortic aneurysms (AAAs) are associated with overall high mortality in case of rupture. Since the pathophysiology is unclear, no adequate pharmacological therapy exists. Smooth muscle cells (SMCs) dysfunction and extracellular matrix (ECM) degradation have been proposed as underlying causes. We investigated SMC spatial organization and SMC-ECM interactions in our novel 3-dimensional (3D) vascular model. We validated our model for future use by comparing it to existing 2-dimensional (2D) cell culture. Our model can be used for translational studies of SMC and their role in AAA pathophysiology.

MATERIALS AND METHODS

SMC isolated from the medial layer of were the aortic wall of controls and AAA patients seeded on electrospun poly-lactide-co-glycolide scaffolds and cultured for 5 weeks, after which endothelial cells (EC) are added. Cell morphology, orientation, mechanical properties and ECM production were quantified for validation and comparison between controls and patients.

RESULTS

We show that cultured SMC proliferate into multiple layers after 5 weeks in culture and produce ECM proteins, mimicking their behavior in the medial aortic layer. EC attach to multilayered SMC, mimicking layer interactions. The novel SMC model exhibits viscoelastic properties comparable to biological vessels; cytoskeletal organization increases during the 5 weeks in culture; increased cytoskeletal alignment and decreased ECM production indicate different organization of AAA patients' cells compared with control.

CONCLUSION

We present a valuable preclinical model of AAA constructed with patient specific cells with applications in both translational research and therapeutic developments. We observed SMC spatial reorganization in a time course of 5 weeks in our robust, patient-specific model of SMC-EC organization and ECM production.

Inflammatory Gene Expression of Human Perivascular Adipose Tissue in Abdominal Aortic Aneurysms

OBJECTIVE

Perivascular adipose tissue (PVAT) contributes to vascular homeostasis and is increasingly linked to vascular pathology. PVAT density and volume were associated with abdominal aortic aneurysm (AAA) presence and dimensions on imaging. However, mechanisms underlying the role of PVAT in AAA have not been clarified. This study aimed to explore differences in PVAT from AAA using gene expression and functional tests.

METHODS

Human aortic PVAT and control subcutaneous adipose tissue were collected during open AAA surgery. Gene analyses and functional tests were performed. The control group consisted of healthy aorta from non-living renal transplant donors. Gene expression tests were performed to study genes potentially involved in various inflammatory processes and AAA related genes. Live PVAT and subcutaneous adipose tissue (SAT) from AAA were used for ex vivo co-culture with smooth muscle cells (SMCs) retrieved from non-pathological aortas.

RESULTS

Adipose tissue was harvested from 27 AAA patients (n [gene expression] = 22, n [functional tests] = 5) and five control patients. An increased inflammatory gene expression of PTPRC (p = .008), CXCL8 (p = .033), LCK (p = .003), CCL5 (p = .004) and an increase in extracellular matrix breakdown marker MMP9 (p = .016) were found in AAA compared with controls. Also, there was a decreased anti-inflammatory gene expression of PPARG in AAA compared with controls (p = .040). SMC co-cultures from non-pathological aortas with PVAT from AAA showed increased MMP9 (p = .033) and SMTN (p = .008) expression and SAT increased SMTN expression in these SMC.

CONCLUSION

The data revealed that PVAT from AAA shows an increased pro-inflammatory and matrix metallopeptidase gene expression and decreased anti-inflammatory gene expression. Furthermore, increased expression of genes involved in aneurysm formation was found in healthy SMC co-culture with PVAT of AAA patients. Therefore, PVAT from AAA might contribute to inflammation of the adjacent aortic wall and thereby plays a possible role in AAA pathophysiology. These proposed pathways of inflammatory induction could reveal new therapeutic targets in AAA treatment.

Image Fusion During Standard and Complex Endovascular Aortic Repair, to Fuse or Not to Fuse? A Meta-analysis and Additional Data From a Single-Center Retrospective Cohort

PURPOSE

To determine if image fusion will reduce contrast volume, radiation dose, and fluoroscopy and procedure times in standard and complex (fenestrated/branched) endovascular aneurysm repair (EVAR).

MATERIALS AND METHODS

A search of the PubMed, Embase, and Cochrane databases was performed in December 2019 to identify articles describing results of standard and complex EVAR procedures using image fusion compared with a control group. Study selection, data extraction, and assessment of the methodological quality of the included publications were performed by 2 reviewers working independently. Primary outcomes of the pooled analysis were contrast volume, fluoroscopy time, radiation dose, and procedure time. Eleven articles were identified comprising 1547 patients. Data on 140 patients satisfying the study inclusion criteria were added from the authors' center. Mean differences (MDs) are presented with the 95% confidence interval (CI).

RESULTS

For standard EVAR, contrast volume and procedure time showed a significant reduction with an MD of -29 mL (95% CI -40.5 to -18.5, p<0.001) and -11 minutes (95% CI -21.0 to -1.8, p<0.01), respectively. For complex EVAR, significant reductions in favor of image fusion were found for contrast volume (MD -79 mL, 95% CI -105.7 to -52.4, p<0.001), fluoroscopy time (MD -14 minutes, 95% CI -24.2 to -3.5, p<0.001), and procedure time (MD -52 minutes, 95% CI -75.7 to -27.9, p<0.001).

CONCLUSION

The results of this meta-analysis confirm that image fusion significantly reduces contrast volume, fluoroscopy time, and procedure time in complex EVAR but only contrast volume and procedure time for standard EVAR. Though a reduction was suggested, the radiation dose was not significantly affected by the use of fusion imaging in either standard or complex EVAR.

Gutter Characteristics and Stent Compression of Self-Expanding vs Balloon-Expandable Chimney Grafts in Juxtarenal Aneurysm Models

Purpose: To assess in silicone juxtarenal aneurysm models the gutter characteristics and compression of different types of chimney graft (CG) configurations. Materials and Methods: Fifty-seven combinations of Excluder C3 or Conformable Excluder stent-grafts (23, 26, and 28.5 mm) were deployed in 2 silicone juxtarenal aneurysm models with 3 types of CGs: Viabahn self-expanding (VSE; 6 and 13 mm) or Viabahn balloon-expandable (VBX; 6, 10, and 12 mm) stent-grafts and Advanta V12 balloon-expandable stent-grafts (ABX; 6 and 12 mm). Setups were divided into 4 groups on the basis of increasing CG and main graft (MG) diameters. Two independent observers assessed gutter size and type as well as CG compression on computed tomography scans using postprocessing software. Results: In the smaller diameter combinations (6-mm CG and 23-, 26-, and 28.5-mm MGs), both VSE (p=0.006 to 0.050) and ABX (p=0.045 to 0.050) showed lower gutter areas and volumes compared with VBX. In turn, the VBX showed a nonsignificant tendency to decreased compression, especially compared to ABX. Use of the Excluder C3 showed a 6-fold increase in type A1 gutters (related to type Ia endoleak) as compared to the Conformable Excluder (p=0.018). Balloon-expandable stent-grafts (both ABX and VBX) showed a 3-fold increase in type A1 gutters in comparison with self-expanding stent-grafts (p=0.008). Conclusion: The current study suggests that use of the Conformable Excluder in combination with VSE chimney grafts is superior to the other tested CG/MG combinations in terms of gutter size, gutter type, and CG compression.

Editor's Choice - Nationwide Analysis of Patients Undergoing Iliac Artery Aneurysm Repair in the Netherlands

OBJECTIVE

The new 2019 guideline of the European Society for Vascular Surgery (ESVS) recommends consideration for elective iliac artery aneurysm (eIAA) repair when the iliac diameter exceeds 3.5 cm, as opposed to 3.0 cm previously. The current study assessed diameters at time of eIAA repair and ruptured IAA (rIAA) repair and compared clinical outcomes after open surgical repair (OSR) and endovascular aneurysm repair (EVAR).

METHODS

This retrospective observational study used the nationwide Dutch Surgical Aneurysm Audit (DSAA) registry that includes all patients who undergo aorto-iliac aneurysm repair in the Netherlands. All patients who underwent primary IAA repair between 1 January 2014 and 1 January 2018 were included. Diameters at time of eIAA and rIAA repair were compared in a descriptive fashion. The anatomical location of the IAA was not registered in the registry. Patient characteristics and outcomes of OSR and EVAR were compared with appropriate statistical tests.

RESULTS

The DSAA registry comprised 974 patients who underwent IAA repair. A total of 851 patients were included after exclusion of patients undergoing revision surgery and patients with missing essential variables. eIAA repair was carried out in 713 patients, rIAA repair in 102, and symptomatic IAA repair in 36. OSR was performed in 205, EVAR in 618, and hybrid repairs and conversions in 28. The median maximum IAA diameter at the time of eIAA and rIAA repair was 43 (IQR 38-50) mm and 68 (IQR 58-85) mm, respectively. Mortality was 1.3% (95% CI 0.7-2.4) after eIAA repair and 25.5% (95% CI 18.0-34.7) after rIAA repair. Mortality was not significantly different between the OSR and EVAR subgroups. Elective OSR was associated with significantly more complications than EVAR (intra-operative: 9.8% vs. 3.6%, post-operative: 34.0% vs. 13.8%, respectively).

CONCLUSION

In the Netherlands, most eIAA repairs are performed at diameters larger than recommended by the ESVS guideline. These findings appear to support the recent increase in the threshold diameter for eIAA repair.

A multilayer micromechanical elastic modulus measuring method in ex vivo human aneurysmal abdominal aortas

Abdominal aortic aneurysms (AAA) are common and potentially life-threatening aortic dilatations, due to the effect of hemodynamic changes on the aortic wall. Previous research has shown a potential pathophysiological role for increased macroscopic aneurysmal wall stiffness; however, not investigating micromechanical stiffness. We aimed to compile a new protocol to examine micromechanical live aortic stiffness (elastic moduli), correlated to histological findings with quantitative immunofluorescence (QIF). Live AAA biopsies (n = 7) and non-dilated aortas (controls; n = 3) were sectioned. Local elastic moduli of aortic intima, media and adventitia were analysed in the direction towards the lumen and vice versa with nanoindentation. Smooth muscle cells (SMC), collagen and fibroblasts were examined using QIF. Nanoindentation of AAA vs. controls demonstrated a 4-fold decrease in elastic moduli (p = 0.022) for layers combined and a 26-fold decrease (p = 0.017) for media-to-intima direction. QIF of AAA vs. controls revealed a 4-, 3- and 6-fold decrease of SMC, collagen and fibroblasts, respectively (p = 0.036). Correlations were found between bidirectional intima and media measurements (ρ = 0.661, p = 0.038) and all QIF analyses (ρ = 0.857-0.905, p = 0.002-0.007). We present a novel protocol to analyse microscopic elastic moduli in live aortic tissues using nanoindentation. Hence, our preliminary findings of decreased elastic moduli and altered wall composition warrant further microscopic stiffness investigation to potentially clarify AAA pathophysiology and to explore potential treatment by wall strengthening. STATEMENT OF SIGNIFICANCE: Although extensive research on the pathophysiology of dilated abdominal aortas (aneurysms) has been performed, the exact underlying pathways are still largely unclear. Previously, the macroscopic stiffness of the pathologic and healthy aortic wall has been studied. This study however, for the first time, studied the microscopic stiffness changes in live tissue of dilated and non-dilated abdominal aortas. This new protocol provides a device to analyse the alterations on cellular level within their microenvironment, whereas previous studies studied the aorta as a whole. Outcomes of these measurements might help to better understand the underlying origin of the incidence and progression of aneurysms and other aortic diseases.