Vascular Implantation Research Articles

Five-year clinical outcomes of STEMI patients treated with a pre-specified bioresorbable vascular scaffold implantation technique: Final results of the BVS STEMI STRATEGY-IT

BackgroundData on Absorb bioresorbable vascular scaffold (BVS) use in patients presenting with ST-segment elevation myocardial infarction (STEMI) are limited. Furthermore, Absorb studies including STEMI patients lacked a prespecified implantation technique to optimize BVS deployment. This study examines the 5-year outcomes of BVS in STEMI patients using an optimized implantation strategy and the impact of prolonged dual antiplatelet therapy (DAPT). MethodsThe BVS STEMI STRATEGY-IT study is a prospective, non-randomized, single-arm multicenter trial (NCT02601781). It involved 505 STEMI patients undergoing primary percutaneous coronary intervention with a predefined BVS implantation protocol. Key endpoints were a 5-year device-oriented composite endpoint (DOCE) of cardiac death, target-vessel myocardial infarction (TV-MI), and ischemia-driven target lesion revascularization (ID-TLR). The study also compared outcomes based on DAPT duration (36 months vs. shorter). Results502 (99.4 %) patients completed the 5-year follow-up. DOCE rate was 2.4 %. ID-TLR, TV-MI, and cardiac death rates were 1.6 %, 0.8 %, and 0.6 %, respectively. No DOCE occurred between three and five years. Scaffold thrombosis (ScT) was 1 %, all occurring within 24 months. Longer-term DAPT significantly reduced DOCE (1.3 % vs. 4.3 %; HR: 0.29; 95 % CI: 0.1–0.9; p = 0.03) driven by a lower rate of TV-MI (0 % vs. 2.2 %; p = 0.018) compared to shorter-term DAPT, as well as ScT (0 % vs 2.7 %, p = 0.007). ConclusionsThis study shows favorable 5-year outcomes for BVS in selected STEMI patients with an optimized implantation strategy. Prolonged DAPT further improved outcomes, emphasizing its role in reducing adverse events during scaffold resorption. Further research is needed to assess newer-generation bioresorbable devices.

Two different hybrid vascular access closure strategies post transcatheter aortic valve implantation

Abstract Background The hybrid strategy combining plug-based and suture-based vascular closure devices (VCD) was introduced as a promising technique for vascular access hemostasis after transcatheter aortic valve implantation (TAVI) with satisfactory outcomes. However, data comparing two plug-based VCDs each in the combination with a suture-based VCD, namely ProGlide/FemoSeal (P/FS) with ProGlide/AngioSeal (P/AS) VCDs, is still lacking. Aim To compare the 30-day outcome of the hybrid strategy using P/AS versus P/FS for vascular access site closure after TAVI. Methods A retrospective single Centre observational study included 608 patients recruited from a prospective TAVI registry between 2016 and 2022. The composite endpoint was defined as any VCD related major vascular complications and/or bleeding more than type 1 according to Valve Academic Research Consortium (VARC-3) criteria. Results The current study reported a significantly higher rate of composite endpoint in P/AS group, which was driven by higher rate of major bleeding (5.4% vs 1.4%, p=0.036). We also found a higher rate of VCD related minor bleeding in P/AS group (16.3% vs 8.1%, p=0.013). Successful access site hemostasis was achieved in 83.1% of P/FS group versus 71.7% in P/AS group (p=0.006). The presence of anterior wall calcification at the access site was significantly associated with the composite endpoint (adj OR 2.49; 95% CI (1.08 – 5.75), p=0.032). Conclusions The hybrid strategy for large bore vascular access closure using P/FS showed a potentially better 30-day outcomes compared with P/AS. The presence of anterior calcification at the access site carries a significant risk of VCD related complications.

Women Experience Higher Rates of Mortality Following Thoracic Endovascular Aneurysm Repair

ObjectivesThoracic endovascular aortic repair (TEVAR) and complex endovascular thoraco-abdominal aneurysm repair (cEVAR) has been increasingly adopted in the treatment of thoracic and thoracoabdominal aorta aneurysms, offering a less invasive approach for patients with appropriate anatomy. Women usually present with smaller aortic diameter. However, they usually have greater aneurysm growth rates. How sex can affect postoperative and short-term outcomes after TEVAR is not well reported. The aim of this study was to assess outcomes in female versus male patients undergoing TEVAR for treatment of thoracic and thoracoabdominal aneurysms in a Medicare-linked database. MethodsWe retrospectively reviewed patients undergoing TEVAR for thoracic and thoracoabdominal aneurysm repair in the Vascular Quality Initiative (VQI) Vascular Implant Surveillance and Interventional Outcomes Network (VISION) database from 2003 to 2018. Patients were divided into males and females. Patients presented with ruptured aneurysm were excluded from the analysis. Postoperative outcomes included in-hospital stroke, myocardial infarction (MI), spinal cord ischemia, and 30-day mortality. One-year outcomes included mortality, aneurysmal rupture, and reintervention. Postoperative outcomes were assessed using multivariable logistic regression analysis and one-year outcomes were evaluated using Kaplan Meier Survival and Cox regression analyses. ResultsA total of 3,058 males and 1,843 females were available for the analysis. Female patients had smaller median aortic diameter, were more likely to be black, with chronic obstructive pulmonary disease, and chronic kidney disease, and to be symptomatic on presentation. Male patients were more likely to be on preoperative medications such as aspirin, beta-blockers, angiotensin-converting enzyme inhibitors, P2Y12 antagonists, and anticoagulants. After adjusting for potential confounders, female gender was associated with double the risk of in-hospital stroke (OR: 2.3, 95%CI ((1.5-3.7), P<0.001) and 80% increase in 30-day mortality (OR: 1.8, 95%CI (1.3-2.6), P=0.001). At one year, female gender was associated with a higher risk of mortality (HR: 1.2, 95%CI (1.05-1.4), P=0.011). There was a trend towards higher risk of reintervention (HR: 1.2, 95%CI (0.97-1.6), P=0.079). ConclusionsMortality after TEVAR seems to be higher in female patients at 30 days and up to one year of follow-up. Female patients also face a two times higher risk of in-hospital stroke. Future studies with a larger female population should aim to identify and potentially ameliorate the factors associated with these unfavorable outcomes in females.

Regional Differences in Vascular Graft Degradation and Regeneration Contribute to Dilation.

Severe coronary artery disease is often treated with a coronary artery bypass graft using an autologous blood vessel. When this is not available, a commercially available synthetic graft can be used as an alternative but is associated with high failure rates and complications. Therefore, the research focus has shifted toward the development of biodegradable, regenerative vascular grafts that can convert into neoarteries. We previously developed an electrospun tropoelastin (TE)-polyglycerol sebacate (PGS) vascular graft that rapidly regenerated into a neoartery, with a cellular composition and extracellular matrix approximating the native aorta. We noted, however, that the TE-PGS graft underwent dilation until sufficient neotissue had been regenerated. This study investigated the mechanisms behind the observed dilation following TE-PGS vascular graft implantation in mice. We saw more pronounced dilation at the graft middle compared with the graft proximal and graft distal regions at 8 weeks postimplantation. Histological analysis revealed less degradation at the graft middle, although the remaining graft material appeared pitted, suggesting compromised structural and mechanical integrity. We also observed delayed cellular infiltration and extracellular matrix (ECM) deposition at the graft middle, corresponding with the area's reduced ability to resist dilation. In contrast, the graft proximal region exhibited greater degradation and significantly enhanced cellular infiltration and ECM regeneration. The nonuniform dilation was attributed to the combined effect of the regional differences in graft degradation and arterial regeneration. Consideration of these findings is crucial for graft optimization prior to its use in clinical applications.

Experimental validation of coronary stenosis severity and development of ischemic myocardium

The current study aimed to evaluate the causal association between hemodynamically significant stenosis and the occurrence of ischemic myocardium using an experimental animal model of coronary artery stenosis. In Yorkshire swine (n = 10), coronary stenosis in the left anterior descending artery was induced using a customized vascular occluder to create varying degrees of occlusion severity (40%-99%). Serial changes in coronary pressure and flow velocity were measured in the left anterior descending artery before and after the implantation of the vascular occluder. At 1 month, 13N-ammonia positron emission tomography (PET) was performed, followed by the collection of isolated hearts for 2,3,5-Triphenyltetrazolium chloride (TTC) staining to quantify the percent area of necrotic myocardium. Three animals in the control group were evaluated using the same protocols, but without the implantation of a vascular occluder Results: The median diameter stenosis after vascular occluder implantation was 61.3% (Q1-Q3: 55.9%-72.3%). Significant differences were observed in hyperemic stenosis resistance, fractional flow reserve (FFR), stress perfusion defect and reversibility in PET, as well as in necrotic myocardium in TTC staining based on stenosis severity (control group: < 50%, 50%-70%, 70%-90%, and > 90%) (all P < .010). Animals with FFR < 0.75 at 1 month exhibited a significantly higher area of stress perfusion defect (30.7 ± 3.1% vs 6.0 ± 4.2%, P < .001), reversibility in PET (11.0 ± 4.0% vs 0.0 ± 0.0%, P = .006), and necrotic myocardium in TTC staining (15.8 ± 6.4% vs 0.0 ± 0.0%, P < .001) than those with FFR ≥ 0.75. In a porcine model, the induction of hemodynamically significant stenosis with FFR < 0.75 was associated with the development of stress perfusion defects and reversibility in PET, as well as necrotic myocardium identified by pathology.

Comparison of Open and Endovascular Repair of Complex Abdominal Aortic Aneurysms

To compare perioperative and 5-year outcomes following endovascular (FEVAR) and open repair (OAR) of complex abdominal aortic aneurysms (cAAA) in males and females separately, given the known sex related differences in perioperative outcomes. We studied all elective cAAA repairs between 2014-2019 in the Vascular Implant Surveillance and Interventional Outcomes Network (VISION) registry. We stratified patients based on sex. We calculated propensity scores for assignment to either OAR or FEVAR. Covariates including age, race, diameter, baseline comorbidities, proximal extent of repair, annual center volumes, and annual surgeon volumes were introduced into the model for estimating propensity scores. Within matched cohorts, perioperative outcomes and 5-year outcomes (mortality, reinterventions, and ruptures) were evaluated using multivariable logistic and Cox regression models. We identified 2,825 patients of whom 29% were female. Within both the sexes, OAR was more commonly performed (OAR vs FEVAR: males: 53% vs 47%; females: 63% vs 37%). After matching, among males (n=1326), FEVAR was associated with lower perioperative mortality (FEVAR vs OAR: 2.3% vs 5.1%; p<.001). However, FEVAR was associated with comparable 5-year mortality (38% vs 28%; hazard ratio (HR) 1.2 [0.92-1.4]; p=.22) and a higher hazard of 5-year reintervention (19% vs 3.7%; aHR: 4.5 [2.6-7.6], p<.001). Among females (n=456), FEVAR and OAR showed similar perioperative mortality (8.3% vs 7.0%; p=.73). At 5 years, FEVAR was associated with higher hazards of mortality (43% vs 32%; aHR: 1.5 [1.03-2.2], p=.034) and reintervention (20% vs 3.0%; aHR: 4.8 [2.1-11], p<.001) compared with OAR. Among males, FEVAR was associated with favorable perioperative outcomes compared with OAR, though these advantages attenuate over time. However, among females, FEVAR was associated with similar perioperative outcomes, eventually leading to higher reinterventions and possibly higher mortality within 5 years. Future efforts should focus on determining the factors associated with these sex disparities to improve outcomes following FEVAR in females. Based on current evidence, females undergoing elective cAAA repair should be selected with due caution, especially for endovascular repair.

Semi-quantitative elemental imaging of corrosion products from bioabsorbable Mg vascular implants in vivo

While metal materials historically have served as permanent implants and were designed to avoid degradation, next generation bioabsorbable metals for medical devices such as vascular stents are under development, which would elute metal ions and corrosion byproducts into tissues. The fate of these eluted products and their local distribution in vascular tissue largely under studied. In this study, we employ a high spatial resolution spectrometric imaging modality, laser ablation inductively coupled plasma time-of-flight mass spectrometry (LA-ICP-TOF-MS) to map the metal distribution, (herein refered to as laser ablation mapping, or LAM) from Mg alloys within the mouse vascular system and approximate their local concentrations. We used a novel rare earth element bearing Mg alloy (WE22) wire implanted within the abdominal aorta of transgenic hypercholesterolemic mice (APOE−/−) to simulate a bioabsorbable vascular prosthesis for up to 30 days. We describe qualitatively and semi-quantitatively implant-derived corrosion product presence throughout the tissue cross sections, and their approximate concentrations within the various vessel structures. Additionally, we report the spatial changes of corrosion products, which we postulate are mediated by phagocytic inflammatory cells such as macrophages (MΦ’s).

“Synergistic anticoagulant and endothelial regeneration strategy” based on mussel-inspired phospholipid copolymer coating and bioactive zeolitic imidazolate frameworks-90 to maintain the patency of CoCr stent

Given the risks of poor patient compliance and bleeding associated with current dual antiplatelet therapies, it is urgent to develop the next generation of cardiovascular stents with anticoagulation and rapid endothelialization capabilities. Inspired by the prominent bioactivity and bioavailability of zeolitic imidazolate framework-90 (ZIF-90) in driving endothelial cell (EC) morphogenesis, this research proposes a “synergistic anticoagulant and endothelial regeneration strategy” depending on mussel-inspired phospholipid copolymer (MIPC) and ZIF-90. Depending on the copolymerization of the catechol with dopamine (Dopa) monomers, Dopa/MIPC coating was immobilized on the surface of CoCr via a one-pot process for resisting the initial thrombosis induced by platelets and fibrinogen. Meanwhile, ZIF-90 was loaded on the coating via coordination effect, aiming to accelerate the proliferation and migration of ECs. Compared with CoCr, the well-designed CoCr-Dopa/MIPC@ZIF-90 not only reduced fibrinogen adhesion by approximately 40 % and platelet adhesion by almost 55 %, but also promoted the proliferation and migration of ECs significantly in vitro. Furthermore, the blood flow velocity of CoCr-Dopa/MIPC@ZIF-90 stent was similar to natural aorta and ECs coverage on it was greatly strengthened after 30 days in a rat aorta vascular stent implantation model. Collectively, CoCr-Dopa/MIPC@ZIF-90 exhibited obvious superiority in reducing the formation of thrombus and promoting endothelial regeneration, which might meet the high requirement for the next generation of vascular stent.

Benchtop Flow Stasis Quantification: In Vitro Methods and In Vivo Possibilities.

Neo-sinus flow stasis has ben correlated with transcatheter heart valve (THV) thrombosis severity and occurrence. Standard benchtop flow field quantification techniques require optical access or modified prosthesis models that may not reflect the true nature of the original valve. En face and fluoroscopic videodensitometry enable visualization of washout in regions otherwise unviewable. This study compares two in vitro methods of assessing flow stasis in scenarios with insufficient optical access for traditional techniques such as particle image velocimetry (PIV). A series of seven paired experiments were conducted using a previously described laser-enhanced video densitometry (LEVD) and fluoroscopic video densitometry (FVD). Both sets of experiments were analyzed to calculate washout time as a measure of flow stasis. A novel flow stasis measure termed contrast attenuation ratio (CAR) is proposed as a viable single measure of flow stasis obtainable from only a small number of cardiac cycles of in vitro or in vivo fluoroscopic data. Retrospective fluoroscopic datasets (n = 72) were analyzed to assess the feasibility of obtaining this metric from routine clinical practice and its ability to stratify results. Neo-sinus flow stasis calculated from in vitro fluoroscopy was well correlated with LEVD (r2 = 0.77, p = 0.009). The newly proposed CAR metric showed good agreement with the commonly used "washout time" measure of flow stasis (r2 = 0.91, p < 0.001) while allowing for assessment with incomplete or truncated data. As a proof of concept, CAR was measured in 72 consecutive retrospective fluoroscopic datasets. CAR averaged 10.6 ± 4.6% with a range of 1.5-20.3% in these patients. This study demonstrates two in vitro methods that can be used to assess relative flow stasis in otherwise optically inaccessible regions surrounding cardiac or vascular implants. In addition, the fluoroscopic benchtop technique was used to validate a metric that allows for extension to routine clinical fluoroscopy. This contrast attenuation ratio (CAR) metric was found to be both accurate and clinically obtainable, and potentially offers a new method for valve thrombosis risk stratification.

Incidence and predictors of vascular complications following transcatheter aortic valve implantation: A comparison of the MANTA and suture-based vascular closure devices.

Vascular complications post-transcatheter aortic valve implantation (TAVI) are common. Recent data regarding predictors of vascular complications are limited, particularly comparing newer plug-based devices versus traditional suture-based vascular closure devices (VCD). The primary objective was to identify characteristics that predict a higher risk of vascular complications in TAVI patients, as judged by the VARC-3 criteria, specifically comparing risk factors between suture-based vs MANTA device closure. Retrospective analysis of patients who underwent TAVI between December 2019 and September 2023 was performed. Logistic regression and propensity score matching was performed to ascertain risk factors for vascular complications post-TAVI. Of the 1763 patients, there were 106 vascular complications (6%). There was a nonsignificant increased complication rate in MANTA vs suture-based device closure (8.3% vs 5.3%, p = 0.064). Among these, the most common complications were VCD failure (23%), pseudoaneurysm (20%) and arterial dissection (19%). Obesity (p = 0.021), anemia (p = 0.039) and MANTA device use (p = 0.027) were predictors of vascular complications. Within the MANTA cohort, novel oral anticoagulant (NOAC) use was predictive of vascular complications (p = 0.002). Among suture-based devices, obesity (p = 0.037) and anaemia (p = 0.017) were significant predictors. A propensity matched analysis derived 90 pairs of patients matched for age, gender, diabetes, peripheral arterial disease, NOAC use, anemia and obesity, identifying an average treatment effect of 0.039 (p = 0.04) when MANTA device closure was performed. Vascular complications in TAVI remain common. Identifying predictors such as MANTA device closure, obesity, anemia, and baseline NOAC use will allow for improved risk stratification and appropriate VCD selection in patients undergoing TAVI.

Preventing Sheep Carotid Artery Spasm for Vascular Graft Surgery and Computed Tomography Angiography.

The development of small-diameter vascular grafts requires testing in large animal models before advancing to clinical trials. Vascular graft interposition implantation in sheep carotid arteries (CAs) is the most widely used model, but ovine CAs are prone to severe spasm following surgical manipulation, potentially impairing graft performance assessment. There is paucity in the literature on reducing sheep CA spasm using effective vasodilator therapeutic protocols. In this study, four healthy Merino cross White Suffolk wethers (1-2 years, 52.1 ± 0.8 kg) underwent CT angiography and CA graft surgery. CT angiography using iodinated contrast agent was performed with innominate artery access through the CA or ascending aortic arch access through the femoral artery. Sheep then underwent right CA sham surgery or left CA vascular graft implantation. A variety of vasodilators, including papaverine, sodium nitroprusside, verapamil, and their combination, were tested for preventing or treating CA spasms intraoperatively. Blood flow was reassessed immediately after CA surgery using CT angiography. The results showed that innominate artery access through the CA for CT angiography in sheep induced presurgical CA spasm with reduced arterial flow. Conversely, ascending aortic arch access through the femoral artery for CT angiography did not cause CA spasm and maintained arterial flow. During CA graft surgery, surgical trauma induced CA spasm, which was prevented by localized intra-arterial administration of vasodilators papaverine hydrochloride and verapamil before significant surgical manipulation.

Incidence and Predictors of Vascular Complications Post-Transcatheter Aortic Valve Implantation: A Comparison of Closure Devices

Incidence and Predictors of Vascular Complications Post-Transcatheter Aortic Valve Implantation: A Comparison of Closure Devices

Correlation between lipoprotein(a) and recurrent ischemic events post-cerebral vascular stent implantation

Background and aimThe association of Lipoprotein(a) (Lp[a]) with recurrent ischemic events in stented patients remains uncertain. So, this research aimed to investigate the impact of elevated Lp(a) levels on the occurrence of ischemic events in this specific patient population. MethodsTotally 553 patients who underwent intracranial or extracranial artery stent implantation were included. Baseline data were collected and postoperative ischemic outcomes were followed up. Cox regression analysis was used to investigate the association between Lp(a) and outcomes, while accounting for confounding factors. Finally, we established prediction models based on nomogram. ResultsOf total 553 patients, a number of 107 (19.3%) experienced outcomes. These included 46 cases (25.4%) in group with elevated Lp(a) levels (>30 mg/dL) and 61 cases (16.4%) in non-elevated group (χ2=6.343, p=0.012). The group with elevated Lp(a) was 1.811 times more likely to experience ischemic events than the non-elevated group, each 1 mg/dL increase in Lp(a) resulted in a 1.008-fold increase in the recurrence rate of ischemic events. In addition, sex (male), previous history of coronary heart disease, decreased albumin, elevated very low density lipoprotein cholesterol and poorly controlled risk factors (including blood pressure and blood sugar) were also associated with a high risk of recurrent ischemic events after stent implantation. ConclusionLp(a) elevation was a significant risk factor for ischemic events in symptomatic patients who underwent intracranial or extracranial artery stenting.

Readmissions Following Endovascular Thoracic and Thoracoabdominal Aortic Repairs in the Vascular Implant Surveillance and Interventional Outcomes Network (VISION)

ObjectivesInvestigate readmission rates, diagnoses associated with readmission, and associations with mortality through 90-days post-operatively after elective endovascular thoracic and thoracoabdominal aortic repair overall and by extent of coverage. MethodsA cohort of index elective non-traumatic endovascular thoracic and thoracoabdominal aortic cases from 2010-2018 was derived from the Vascular Implant Surveillance and Interventional Outcomes Network. Cohort readmissions within 90-days postoperative were examined both overall and by Crawford extent (CE) of aortic coverage. Postoperative mortality was examined by reason for readmission and CE. ResultsThe cohort consisted of 2,093 patients who underwent endovascular thoracic and thoracoabdominal aortic repair (1,541 CE 0A/0B; 240 CE 1-3; 312 CE 4-5). Cumulative risk for 90-day readmission was 34.3% in CE 0A/0B repairs, 33.4% in CE4-5 repairs and 47.4% in CE 1-3 repairs. Compared to CE 0A/B, patients with CE 1-3 repairs experienced an increased risk of readmission within 90 days postoperatively after adjusting for preoperative factors (aHR 1.27(1.00,1.61) while the readmission risk for CE 4-5 repairs did not differ significantly (aHR 0.83 (0.64,1.06). Significant risk factors for 90-day readmission included COPD, dialysis dependence, limited ambulation, visceral/spinal ischemia, and in-hospital stroke. Discharge to home was protective against readmission (HR 0.65, CI 0.54-0.79). Patients with a readmission within 90-days had a 7.89-fold increase in 90-day mortality (HR 7.84; 5.17, 11.9) compared to those not readmitted. ConclusionsIncreasing extent of endovascular thoracic and thoracoabdominal aortic repair was associated with higher 90-day readmission rates. Readmission for all CE was associated with near 8-fold increased risk of mortality. Risk factors associated with increased risk for readmission included pulmonary insufficiency, renal disease, and poor functional status. These findings can inform stakeholders about investment of resources to improve processes of care that both target prevention and mitigate risk of readmission after elective endovascular thoracic and thoracoabdominal aortic repair.

Duplex Ultrasound–Only Surveillance after Endovascular Abdominal Aortic Aneurysm Repair is Associated with Favorable Long-Term Outcomes

ObjectiveLong-term data surrounding the impact of different endovascular abdominal aortic aneurysm repair (EVAR) surveillance strategies is limited. Therefore, the purpose of this study was to characterize postoperative imaging patterns, as well as to evaluate the association of duplex ultrasound surveillance after the first postoperative year with 5-year EVAR outcomes. MethodsEVAR patients (2003-2016), who survived at least 1-year without aneurysm rupture, conversion to open repair, and reintervention in the Vascular Implant Surveillance and Interventional Outcomes Network (VISION) were examined to provide all subjects ≥3-years of follow-up time. Patients were categorized into 6 cohorts after the first postoperative year: No imaging (N=953); CT/MRI-only (N=2,976); Duplex ultrasound-only (DUS; N=1,808); Combined CT/MRI+DUS with >50% being CT/MRI (N=1,937); Combined CT/MRI+DUS with >50% being DUS (N=2,253); and Mixed (CT+DUS+MRI-N=1,272). Abdominal aortic aneurysm (AAA) related re-intervention, rupture, conversion to open repair, and all-cause mortality were estimated using Kaplan-Meier analysis. Multivariable logistic regression models identified variables associated with using DUS-only imaging (vs. CT/MRI only). Cox regression models compared 5-year outcomes between patients receiving DUS-only vs. CT/MRI-only imaging. ResultsA total of 11,199 EVAR patients were examined (mean age-76±7 years; female-20%; non-elective-10%). DUS-only imaging surveillance after the first postoperative year was more likely to occur after elective repairs, as well as among older, male patients. Smaller (<6cm) preoperative AAA diameter and absence of documented concurrent iliac aneurysm was also associated with DUS-only follow-up. Additionally, no endoleak detection on index EVAR completion imaging, as well as a documented >5mm decrease in AAA sac diameter at 1-year follow-up was more common with DUS-only surveillance protocols. Post-EVAR DUS-only imaging after the first postoperative year had the lowest incidence of re-intervention, conversion to open repair, and rupture (as well as the composite reintervention/open conversion/rupture; log-rank P<.001 for all). Further, patients receiving exclusively DUS after their first postoperative year had better overall survival (log-rank P<.001). These outcome advantages that were associated with DUS-only surveillance compared with CT/MRI-only surveillance after EVAR persisted when controlling for baseline co-variates, preoperative AAA diameter, prior aortic surgery history, sac growth, and presence of endoleak (all P<.01). ConclusionsEVAR patients selected for DUS-only surveillance after the first postoperative year have excellent freedom from AAA-related reintervention, conversion to open repair, rupture and all-cause mortality. These findings remained on multivariable analysis after adjusting for baseline characteristics, endoleak status and sac diameter changes within the first year. This is the first registry-based investigation to document long-term EVAR outcomes for patients entered into a DUS-only monitoring protocol which serves to corroborate the growing evidence base that DUS may be able to supplant CT surveillance in certain subgroups. A prospective randomized multi-center trial comparing DUS versus CT-based imaging after EVAR is needed to validate these findings which may serve to change current practice guidelines, as well as industry and regulatory stakeholder requirements.

Long-term outcomes of great saphenous vein harvest techniques for infrainguinal arterial bypass in a Medicare-matched registry database

ObjectiveLong-term outcomes for harvesting techniques for great saphenous vein (GSV) and its impact on the outcomes of infrainguinal arterial bypass remains largely unknown. Endoscopic GSV harvesting (EVH) has emerged as a less invasive alternative to conventional open techniques. Using the Vascular Quality initiative Vascular Implant Surveillance & Interventional Outcomes Network (VQI-VISION) database, we compared the long-term outcomes of infrainguinal arterial bypass using open and endoscopic GSV harvest techniques. MethodsPatients who underwent infrainguinal GSV bypass between 2010 and 2019 were identified in the VQI-VISION Medicare linked database. Long-term outcomes of major/minor amputations, and reinterventions up to 5 years of follow-up were compared between continuous incisions, skip incision, and EVH, with continuous incisions being the reference group. Secondary outcomes included 30- and 90-day readmission, in addition to surgical site infections and patency rates at 6 months to 2 years postoperatively. Survival analysis using Kaplan-Meier curves and Cox regression hazard models were utilized to compare outcomes between groups. To adjust for multiple comparisons between the study groups, a P value of 2.5% was considered significant. ResultsAmong the 8915 patients included in the study, continuous and skip vein harvest techniques were used in 44.4% and 43.4% of cases each, whereas 12.3% underwent EVH. The utilization of EVH remained relatively stable at around 12% throughout the study period. Compared with GSV harvest using continuous incisions, EVH was associated with higher rates of reintervention at 1 year (46.5% vs 41.3%; adjusted hazard ratio [aHR], 1.22; 95% confidence interval [CI], 1.06-1.41; P = .01]. However, no significant difference was observed between EVH and continuous incisions, and between skip and continuous incisions in terms of long-term reintervention or major and minor amputations on adjusted analysis. Compared with continuous incision vein harvest, both EVH and skip incisions were associated with lower surgical site infection rates within the first 6 months post-bypass (aHR, 0.53; 95% CI, 0.35-0.82 and aHR, 0.68; 95% CI, 0.53-0.87, respectively). Loss of primary, primary-assisted, and secondary patency was higher after EVH compared with continuous incision vein harvest. Among surgeons performing EVH, comparable long-term outcomes were observed regardless of low (<4 cases/year), medium (4-7 cases/year), or high procedural volumes (>7 cases/year). ConclusionsDespite higher 1-year reintervention rates, EVH for infrainguinal arterial bypass is not associated with a significant difference in long-term reintervention or amputation rates compared with other harvesting techniques. These outcomes are not influenced by procedural volumes for EVH technique.

Biological evaluation of femtosecond-laser-textured Fe–Mn alloys for vascular applications

Biodegradable metals represent a valuable solution for the development of temporary vascular implants. These are expected to dissolve in the body over time, avoiding side effects typical of permanent implants, such as thrombosis, in-stent restenosis and chronic inflammation. Iron (Fe)-based alloys, such as iron–manganese (Mn) alloys, are of particular interest for cardiovascular applications due to their intrinsic properties. However, their degradation behavior and biological performance need to be improved. Femtosecond (fs)-laser-induced surface topography could affect both their degradation and cell–material interaction. In this work, fs-laser-induced patterning was performed on a Fe–Mn20 alloy to tune both the degradation behavior of the material and its interaction with the biological environment for cardiovascular applications. Processing parameters were varied to select an optimized surface morphology, characterized by linear grooves. Profilometric analysis, scanning electron microscopy and degradation rate analysis were performed on the treated samples. Thereafter, endothelial cell viability tests and hemocompatibility assessment were carried out on selected process conditions. The obtained fs-laser-induced linear patterns were demonstrated to decrease the degradation rate and to improve the biological response toward both endothelial cells and blood. These results demonstrate how fs-laser-induced patterning is a promising solution for the development of biodegradable metal-based vascular implants.

A review on the surface topography and corrosion behavior of Mg-alloy coatings for biomedical implants

Osteoconductive, biocompatible, and biodegradable magnesium alloys hold great promise as novel materials for orthopaedic and vascular implants due to their bone-like mechanical properties. Furthermore, their limited utility in therapeutic environments is compounded by their inadequate resistance to corrosion. Because the impulsive occurrence of corrosion in magnesium alloys is governed by the loss of properties, including the materials' fundamental properties and various corrosive conditions, the corrosion mechanism is extremely complex. Due to the incidence of numerous factors, including the materials' inherent properties and the presence of various corrosive environments, the corrosion mechanism of magnesium alloys is complexity-ridden.

3D printing of an artificial intelligence-generated patient-specific coronary artery segmentation in a support bath

Accurate segmentation of coronary artery tree and personalized 3D printing from medical images is essential for CAD diagnosis and treatment. The current literature on 3D printing relies solely on generic models created with different software or 3D coronary artery models manually segmented from medical images. Moreover, there are not many studies examining the bioprintability of a 3D model generated by artificial intelligence (AI) segmentation for complex and branched structures. In this study, deep learning algorithms with transfer learning have been employed for accurate segmentation of the coronary artery tree from medical images to generate printable segmentations. We propose a combination of deep learning and 3D printing, which accurately segments and prints complex vascular patterns in coronary arteries. Then, we performed the 3D printing of the AI-generated coronary artery segmentation for the fabrication of bifurcated hollow vascular structure. Our results indicate improved performance of segmentation with the aid of transfer learning with a Dice overlap score of 0.86 on a test set of 10 coronary tomography angiography images. Then, bifurcated regions from 3D models were printed into the Pluronic F-127 support bath using alginate + glucomannan hydrogel. We successfully fabricated the bifurcated coronary artery structures with high length and wall thickness accuracy, however, the outer diameters of the vessels and length of the bifurcation point differ from the 3D models. The extrusion of unnecessary material, primarily observed when the nozzle moves from left to the right vessel during 3D printing, can be mitigated by adjusting the nozzle speed. Moreover, the shape accuracy can also be improved by designing a multi-axis printhead that can change the printing angle in three dimensions. Thus, this study demonstrates the potential of the use of AI-segmented 3D models in the 3D printing of coronary artery structures and, when further improved, can be used for the fabrication of patient-specific vascular implants.

PMMA/PDMS/MXene Nanofibers for Postsurgery Monitoring of Vascular Implants

PMMA/PDMS/MXene Nanofibers for Postsurgery Monitoring of Vascular Implants