Discrepancies in clavicle-to-carotid bifurcation length measurements for transcarotid artery revascularization using different imaging modalities.

OBJECTIVE: Transcarotid artery revascularization (TCAR) has emerged as an effective method for carotid artery stenting. However, anatomic eligibility for TCAR is most often limited by an inadequate clavicle-to-carotid bifurcation length of <5 cm. Preoperative clavicle-to-carotid bifurcation distances may be underestimated when using conventional straight-line measurements on computed tomographic angiography (CTA) imaging. We therefore compared clavicle-to-carotid bifurcation lengths as measured by straight-line CTA, center-line CTA, and intraoperative duplex ultrasound (US), to assess potential differences. METHODS: We conducted a single-center, retrospective review of consecutive TCAR procedures performed between 2016 and 2019 for atherosclerotic carotid disease. For each patient, we compared clavicle-to-carotid bifurcation lengths measured by straight-line CTA, center-line CTA using TeraRecon image reconstruction, and intraoperative duplex US with neck extension and rotation. We further assessed patient and imaging characteristics in individuals with a ≥0.5 cm difference among the measurement methods. In particular, common carotid artery (CCA) tortuosity, defined as the inability to visualize the entire CCA from clavicle to carotid bifurcation on both a single coronal and sagittal imaging cut, was examined as a contributing factor for these discrepancies. RESULTS: Of the 70 TCAR procedures identified, 46 had all three imaging modalities available for review. The median clavicle-to-carotid bifurcation length was found to be 6.4 cm (interquartile range [IQR], 5.4-6.7 cm) on straight-line CTA, 7.0 cm (IQR, 6.0-7.5 cm) on intraoperative duplex US, and 7.2 cm (IQR, 6.5-7.5 cm) on center-line CTA (P < .001). Patients with a ≥0.5 cm difference between their straight-line CTA and either their intraoperative duplex US or center-line CTA measurements were more likely to have tortuous CCAs (60.0% vs 19.1%; P = .01; 51.4% vs 0.0%; P = .01). There were no notable differences in age, gender, prior neck/cervical spine surgery, or neck immobility among these individuals. In patients with tortuous CCAs, duplex US and center-line CTA measurements added 1.0 cm (IQR, 0.6-1.5 cm) and 1.1 cm (IQR, 0.9-1.6 cm) more in length than straight-line CTA measurements, respectively. There was a strong linear correlation between the additional lengths provided by duplex US measurements and those provided by center-line CTA measurements for each individual within the tortuous CCA group (r = 0.83). CONCLUSIONS: The use of straight-line CTA during preoperative planning can underestimate the clavicle-to-carotid bifurcation lengths in patients undergoing carotid revascularization, particularly in those with tortuous CCAs. Both duplex US performed with extended-neck surgical positioning and center-line CTA provide similar and longer carotid length measurements, and should be utilized in patients with tortuous carotid vessels to better determine TCAR anatomic eligibility.

In-hospital outcomes after carotid endarterectomy for stroke stratified by modified Rankin scale score and time of intervention.

OBJECTIVE: Although the benefits of carotid endarterectomy (CEA) for treating symptomatic carotid stenosis are well known, the optimal timing of intervention after acute stroke and whether the optimal timing will vary with preoperative stroke severity has remained unclear. Therefore, we assessed the effect of stroke severity and timing of the intervention on the postoperative outcomes for patients who had undergone CEA for stroke. METHODS: We identified all patients in the Vascular Quality Initiative who had undergone CEA from 2012 to 2020 for prior stroke. The patients were stratified using the preoperative modified Rankin scale score (mRS score, 0-5) and time to CEA after stroke onset (≤2 days, 3-14 days, 15-90 days, 91-180 days). After univariate comparisons, the patients were stratified into the following mRS cohorts for further analysis: 0 to 1, 2, 3 to 4, and 5. The primary outcome was in-hospital stroke/death. RESULTS: We identified 15,601 patients, of whom 30% had had an mRS score of 0, 34% an mRS score of 1, 17% an mRS score of 2, 11% an mRS score of 3, 8% an mRS score of 4, and 1% an mRS score of 5. Overall, 9.3% of the patients had undergone CEA within ≤2 days, 46% within 3 to 14 days, 36% in 15 to 90 days, and 8.4% within 90 to 180 days. A decreasing mRS score and an increasing time to CEA were associated with lower rates of perioperative stroke/death (Ptrend < .01). After risk adjustment, with CEA at 3 to 14 days as the comparator group, the mRS score 0 to 1 group had had a higher incidence of stroke/death after CEA within ≤2 days (3.6% vs 2.0%; odds ratio [OR], 1.8; 95% confidence interval [CI], 1.2-2.7). The mRS score 2 group had had a similar incidence of stroke/death after CEA within ≤2 days (4.4% vs 3.9%; OR, 1.2; 95% CI, 0.6-2.3) but a lower incidence after CEA at 15 to 90 days (2.1% vs 3.9%; OR 0.5; 95% CI, 0.3-0.96). The mRS score 3 to 4 group had had a higher incidence of stroke/death after CEA within ≤2 days (8.0% vs 3.8%; OR, 2.4; 95% CI, 1.5-3.9) but a similar incidence of stroke/death after CEA at 15 to 90 days (3.0% vs 3.8%; OR, 0.8; 95% CI, 0.5-1.3). For the mRS score 5 group, the stroke/death rates were ≥6.5% across all the time to CEA groups. However, the low sample size limited meaningful comparisons. CONCLUSIONS: Patients with minimal disability after stroke (mRS score, 0-1) seemed to benefit from CEA within 3 to 14 days. However, those with severe disability (mRS score 5) have a very high risk from CEA at any time point given the poor outcomes. In contrast to the current guidelines, patients with mild disability (mRS score 2) could benefit from delaying CEA to 15 to 90 days, and those with moderate disability (mRS score 3-4) might benefit from CEA within 3 to 90 days given the acceptable in-hospital outcomes. These data should be considered within the context of the clinical situation in the weeks after index event to determine the net benefit of delayed CEA.

The impact of completion and follow-up endoleaks on survival, reintervention, and rupture.

OBJECTIVE: Endoleaks may be seen at case completion of endovascular abdominal aortic aneurysm repair (EVAR), and the presence of an endoleak may impact outcomes. However, the clinical implications of various endoleaks seen during follow-up is not well-described. Therefore, we studied the impact of endoleaks at completion and at follow-up on mid-term outcomes. METHODS: We reviewed patients who underwent EVAR from 2003 to 2016 within the Vascular Quality Initiative-Medicare database and identified patients with endoleak at procedure completion and during follow-up, excluding those presenting with rupture. We stratified cohorts by presence of completion and follow-up endoleak subtypes. The primary outcome was 5-year survival, and secondary outcomes included 5-year freedom from reintervention and freedom from rupture. We used Kaplan-Meier estimates and log-rank tests to analyze differences in time-to-event endpoints. RESULTS: Of 21,745 patients with completion endoleak data, 5085 (23%) had an endoleak. Compared with those without endoleak, those with type I endoleaks had lower 5-year survival (69% vs 75%; P < .001), type II endoleaks had higher survival (79%; P < .001), and types III, IV, and indeterminate were not statistically different (73%, 73%, and 75%, respectively). Freedom from reintervention for types I and III endoleaks were significantly lower than no endoleak cohort (I: 76%; P < .001; III: 72%; P < .001 vs 83%), but freedom from rupture was higher for those with type II and III endoleak (95% and 97% vs 94%; P < .001). Of 14,479 patients with detailed follow-up endoleak data, 2290 (16%) had an endoleak. Compared with those without endoleak, types I and III had significantly lower 5-year survival (I: 80%; P = .002; III: 66%; P < .001 vs 84%), but there were no differences for types II (82%) and indeterminate (77%). Those with any type of follow-up endoleak had lower 5-year freedom from reintervention (I: 70%; P < .001; II: 76%; P = .006; III: 36%; P < .001; indeterminate: 60%; P = .007 vs 84%), and lower freedom from rupture (I: 92%; P < .001; II: 91%; P = .16; III: 88%; P = .01; indeterminate: 90%; P = .11 vs 94%). CONCLUSIONS: Compared with patients with no endoleak, those with type I completion endoleaks have lower 5-year survival and freedom from reintervention. Patients with types I and III follow-up endoleaks also have lower survival, and any endoleak at follow-up is associated with lower freedom from reintervention and freedom from rupture. These data highlight the importance of careful patient selection and close postoperative follow-up after EVAR, as the presence of endoleaks, specifically type I and III, over time portends worse outcomes.

In-Hospital Outcomes of Urgent, Early, or Late Revascularization for Symptomatic Carotid Artery Stenosis.

BACKGROUND AND PURPOSE: Advancements in carotid revascularization have produced promising outcomes in patients with symptomatic carotid artery stenosis. However, the optimal timing of revascularization procedures after symptomatic presentation remains unclear. The purpose of this study is to compare in-hospital outcomes of transcarotid artery revascularization (TCAR), transfemoral carotid stenting (TFCAS), or carotid endarterectomy (CEA) performed within different time intervals after most recent symptoms. METHODS: This is a retrospective cohort study of United States patients in the vascular quality initiative. All carotid revascularizations performed for symptomatic carotid artery stenosis between September 2016 and November 2019 were included. Procedures were categorized as urgent (0-2 days after most recent symptom), early (3-14 days), or late (15-180 days). The primary outcome of interest was in-hospital stroke and death. Secondary outcomes include in-hospital stroke, death, and transient ischemic attacks. Multivariable logistic regression was used to compare outcomes. RESULTS: A total of 18 643 revascularizations were included: 2006 (10.8%) urgent, 7423 (39.8%) early, and 9214 (49.42%) late. Patients with TFCAS had the highest rates of stroke/death at all timing cohorts (urgent: 4.0% CEA, 6.9% TFCAS, 6.5% TCAR, P=0.018; early: 2.5% CEA, 3.8% TFCAS, 2.9% TCAR, P=0.054; late: 1.6% CEA, 2.8% TFCAS, 2.3% TCAR, P=0.003). TFCAS also had increased odds of in-hospital stroke/death compared with CEA in all 3 groups (urgent adjusted odds ratio [aOR], 1.7 [95% CI, 1.0-2.9] P=0.03; early aOR, 1.6 [95% CI, 1.1-2.4] P=0.01; and late aOR, 1.9 [95% CI, 1.2-3.0] P=0.01). TCAR and CEA had comparable odds of in-hospital stroke/death in all 3 groups (urgent aOR, 1.9 [95% CI, 0.9-4], P=0.10), (early aOR, 1.1 [95% CI, 0.7-1.7], P=0.66), (late aOR, 1.5 [95% CI, 0.9-2.3], P=0.08). CONCLUSIONS: CEA remains the safest method of revascularization within the urgent period. Among revascularization performed outside of the 48 hours, TCAR and CEA have comparable outcomes.

Salt-Inducible Kinase 3 Promotes Vascular Smooth Muscle Cell Proliferation and Arterial Restenosis by Regulating AKT and PKA-CREB Signaling.

Objective: Arterial restenosis is the pathological narrowing of arteries after endovascular procedures, and it is an adverse event that causes patients to experience recurrent occlusive symptoms. Following angioplasty, vascular smooth muscle cells (SMCs) change their phenotype, migrate, and proliferate, resulting in neointima formation, a hallmark of arterial restenosis. SIKs (salt-inducible kinases) are a subfamily of the AMP-activated protein kinase family that play a critical role in metabolic diseases including hepatic lipogenesis and glucose metabolism. Their role in vascular pathological remodeling, however, has not been explored. In this study, we aimed to understand the role and regulation of SIK3 in vascular SMC migration, proliferation, and neointima formation. Approach and Results: We observed that SIK3 expression was low in contractile aortic SMCs but high in proliferating SMCs. It was also highly induced by growth medium in vitro and in neointimal lesions in vivo. Inactivation of SIKs significantly attenuated vascular SMC proliferation and up-regulated p21CIP1 and p27KIP1. SIK inhibition also suppressed SMC migration and modulated actin polymerization. Importantly, we found that inhibition of SIKs reduced neointima formation and vascular inflammation in a femoral artery wire injury model. In mechanistic studies, we demonstrated that inactivation of SIKs mainly suppressed SMC proliferation by down-regulating AKT (protein kinase B) and PKA (protein kinase A)-CREB (cAMP response element-binding protein) signaling. CRTC3 (CREB-regulated transcriptional coactivator 3) signaling likely contributed to SIK inactivation-mediated antiproliferative effects. Conclusions: These findings suggest that SIK3 may play a critical role in regulating SMC proliferation, migration, and arterial restenosis. This study provides insights into SIK inhibition as a potential therapeutic strategy for treating restenosis in patients with peripheral arterial disease.

Protamine use in transfemoral carotid artery stenting is not associated with an increased risk of thromboembolic events.

BACKGROUND: Protamine use in carotid endarterectomy has been shown to be associated with fewer perioperative bleeding complications without higher rates of thromboembolic events. However, the effect of protamine use on complications after transfemoral carotid artery stenting (CAS) is unclear, and concerns remain about thromboembolic events. METHODS: A retrospective review was performed for patients undergoing transfemoral CAS in the Vascular Quality Initiative from March 2005 to December 2018. We assessed in-hospital outcomes using propensity score-matched cohorts of patients who did and did not receive protamine. The primary outcome was in-hospital stroke or death. Secondary outcomes included bleeding complications, stroke, death, transient ischemic attack, myocardial infarction, and congestive heart failure exacerbation. Bleeding complications were categorized as bleeding resulting in intervention or blood transfusions. RESULTS: Of the 17,429 patients undergoing transfemoral CAS, 2697 (15%) patients received protamine. We created 2300 propensity score-matched pairs of patients who did and did not receive protamine. There were no statistically significant differences in stroke or death between the two cohorts (protamine, 2.5%; no protamine, 2.9%; relative risk [RR], 0.85; 95% confidence interval [CI], 0.60-1.21; P = .37). Protamine use was not associated with statistically significant differences in perioperative bleeding complications resulting in interventional treatment (0.9% vs 0.5%; RR, 2.10; 95% CI, 0.99-4.46; P = .05) or blood transfusion (1.2% vs 1.2%; RR, 0.92; 95% CI, 0.53-1.61; P = .78). There were also no statistically significant differences for the individual outcomes of stroke (1.8% vs 2.3%; RR, 0.78; 95% CI, 0.52-1.16; P = .22), death (0.9% vs 0.8%; RR, 1.17; 95% CI, 0.62-2.19; P = .63), transient ischemic attack (1.4% vs 1.3%; RR, 1.10; 95% CI, 0.67-1.82; P = .70), myocardial infarction (0.5% vs 0.4%; RR, 1.20; 95% CI, 0.52-2.78; P = .67), or heart failure exacerbation (1.0% vs 0.9%; RR, 1.05; 95% CI, 0.58-1.90; P = .88). Protamine use in patients presenting with symptomatic carotid stenosis was associated with lower risk of stroke or death (3.0% vs 4.3%; RR, 0.69; 95% CI, 0.47-0.998; P = .048), whereas there were no statistically significant differences in stroke or death with protamine use in asymptomatic patients (1.6% vs 1.0%; RR, 1.63; 95% CI, 0.67-3.92; P = .28). CONCLUSIONS: Heparin reversal with protamine after transfemoral CAS is not associated with an increased risk of thromboembolic events, and its use in symptomatic carotid disease is associated with a lower risk of stroke or death.

Late outcomes after endovascular and open repair of large abdominal aortic aneurysms.

OBJECTIVE: The risk of aortic abdominal aneurysm (AAA) rupture increases with an increasing aneurysm diameter. However, the effect of the AAA diameter on late outcomes after aneurysm repair is unclear. Therefore, we assessed the association of a large AAA diameter with late outcomes for patients undergoing open and endovascular AAA repair. METHODS: We identified all patients who had undergone elective open or endovascular infrarenal aneurysm repair from 2003 to 2016 in the Vascular Quality Initiative linked to Medicare claims for long-term outcomes. A large AAA diameter was defined as a diameter >65 mm. We assessed the 5-year reintervention, rupture, mortality, and follow-up rates. We constructed propensity scores and used inverse probability-weighted Kaplan-Meier estimations and Cox proportional hazard models to identify independent associations between large AAA repair and our outcomes. RESULTS: Of the 21,119 aneurysm repairs identified, 15.2% were for large AAAs. Of the 21,119 repairs, 19,017 were endovascular and 2102 were open. The large AAA cohort was less likely to have undergone endovascular aneurysm repair (EVAR; 84.9% vs 91%; P < .001), more likely to be older (median age, 76 vs 75 years; P < .001), and were less likely to be women (16.2% vs 21.7%; P < .001). After EVAR, patients with large AAAs had had lower adjusted 5-year freedom from reintervention (73.9% vs 84.6%; P < .001), freedom from rupture (88.5% vs 93.6%; P < .001), survival (58.0% vs 66.4%; P < .001), and freedom from loss to follow-up (77.7% vs 83.3%; P < .001) compared with patients with smaller AAAs. However, after open repair, the adjusted 5-year freedom from reintervention (95.8% vs 93.3%; P = .11), freedom from rupture (97.4% vs 97.8%; P = .32), survival (70.4% vs 74.0%; P = .13), and loss to follow-up (60.5% vs 62.8%; P = .86) were similar to the results for patients with smaller AAAs. For patients with large AAAs, the adjusted 5-year survival was lower after EVAR than that after open repair (55.3% vs 63.7%) but not after smaller AAA repair (67.3% vs 70.6%). CONCLUSIONS: The 5-year adjusted reintervention, ruptures, mortality, and loss to follow-up rates for patients who had undergone large AAA EVAR were higher than those for patients who had undergone small AAA EVAR and large AAA open repair. Therefore, for patients with large AAAs who are medically fit, open repair should be strongly considered. Furthermore, these findings highlight the necessity for rigorous long-term follow-up after EVAR.

A comparison of administrative data and quality improvement registries for abdominal aortic aneurysm repair.

OBJECTIVE: Databases are essential in evaluating surgical outcomes and gauging the implementation of new techniques. However, there are important differences in how data from administrative databases and surgical quality improvement (QI) registries are collected and interpreted. Therefore, we aimed to compare trends, demographics, and outcomes of open and endovascular abdominal aortic aneurysm (AAA) repair in an administrative database and two QI registries. METHODS: We identified patients undergoing open and endovascular repair of intact and ruptured AAAs between 2012 and 2015 within the National Inpatient Sample (NIS), the National Surgical Quality Improvement Program (NSQIP), and the Vascular Quality Initiative (VQI). We described the differences and trends in overall AAA repairs for each data set. Moreover, patient demographics, comorbidities, mortality, and complications were compared between the data sets using Pearson χ2 test. RESULTS: A total of 140,240 NIS patients, 10,898 NSQIP patients, and 26,794 VQI patients were included. Ruptured repairs composed 8.7% of NIS, 11% of NSQIP, and 7.9% of VQI. Endovascular aneurysm repair (EVAR) rates for intact repair (range, 83%-84%) and ruptured repair (range, 51%-59%) were similar in the three databases. In general, rates of comorbidities were lower in NIS than in the QI registries. After intact EVAR, in-hospital mortality rates were similar in all three databases (NIS 0.8%, NSQIP 1.0%, and VQI 0.8%; P = .06). However, after intact open repair and ruptured repair, in-hospital mortality was highest in NIS and lowest in VQI (intact open: NIS 5.4%, NSQIP 4.7%, and VQI 3.5% [P < .001]; ruptured EVAR: NIS 24%, NSQIP 20%, and VQI 16% [P < .001]; ruptured open: NIS 36%, NSQIP 31%, and VQI 26% [P < .001]). After stratification by intact and ruptured presentation and repair strategy, several discrepancies in morbidity rates remained between the databases. Overall, the number of cases in NSQIP represents 7% to 8% of the repairs in NIS, and the number of cases in VQI grew from 12% in 2012 to represent 23% of the national sample in 2015. CONCLUSIONS: NIS had the largest number of patients as it represents the nationwide experience and is an essential tool to evaluate trends over time. The lower in-hospital mortality seen in NSQIP and VQI questions the generalizability of the studies that use these QI registries. However, with a growing number of hospitals engaging in granular QI initiatives, these QI registries provide a valuable resource to potentially improve the quality of care provided to all patients.

Preservation of pelvic perfusion with iliac branch devices does not decrease ischemic colitis compared with hypogastric embolization in endovascular abdominal aortic aneurysm repair.

OBJECTIVE: Ischemic colitis is a rare but devastating complication of endovascular repair of infrarenal abdominal aortic aneurysms. Although it is rare (0.9%) in standard endovascular aneurysm repair (EVAR), the incidence increases to 2% to 3% in EVAR with hypogastric artery embolization (HAE). This study investigated whether preservation of pelvic perfusion with iliac branch devices (IBDs) decreases the incidence of ischemic colitis. METHODS: We used the targeted EVAR module in the American College of Surgeons National Surgical Quality Improvement Program database to identify patients undergoing EVAR of infrarenal abdominal aortic aneurysm from 2012 to 2017. The cohort was further stratified into average-risk and high-risk groups. Average-risk patients were those who underwent elective repair for sizes of the aneurysms, whereas high-risk patients were repaired emergently for indications other than asymptomatic aneurysms. Within these groups, we examined the 30-day outcomes of standard EVARs, EVAR with HAE, and EVAR with IBDs. The primary outcome was the incidence of ischemic colitis. Secondary outcomes included mortality, major organ dysfunction, thromboembolism, length of stay, and return to the operating room. The χ2 test, Fisher exact test, Kruskal-Wallis test, and multivariate regression models were used for data analysis. RESULTS: There were 11,137 patients who had infrarenal EVAR identified. We designated this the all-risk cohort, which included 9263 EVAR, 531 EVAR-HAE, and 1343 EVAR-IBD procedures. These were further stratified into 9016 cases with average-risk patients and 2121 cases with high-risk patients. In the average-risk group, 7482 had EVAR, 411 had EVAR-HAE, and 1123 had EVAR-IBD. In the high-risk group, 1781 had EVAR, 120 had EVAR-HAE, and 220 had EVAR-IBD. There was no significant difference in 30-day outcomes (including ischemic colitis) between EVAR, EVAR-HAE, and EVAR-IBD in the all-risk and high-risk groups. In the average-risk cohort, EVAR-HAE was associated with a higher mortality rate than EVAR (2.2% vs 1.0%; adjusted odds ratio, 2.58; P = .01). Although EVAR-IBD was not superior to EVAR-HAE in 30-day mortality, major organ dysfunction, or ischemic colitis in this average-risk cohort, EVAR-IBD exhibited a trend toward lower mortality compared with EVAR-HAE in this cohort, but it was not statistically significant (1.0% vs 2.2%; adjusted odds ratio, 0.42; P = .07). CONCLUSIONS: Ischemic colitis is a rare complication of EVAR. HAE does not appear to increase the risk of ischemic colitis, and preservation of pelvic perfusion with IBDs does not decrease its incidence. Although HAE is associated with significantly higher mortality than standard EVAR in average-risk patients, the preservation of pelvic perfusion with IBDs does not appear to improve mortality over HAE.

Inferior mesenteric artery replantation does not decrease the risk of ischemic colitis after open infrarenal abdominal aortic aneurysm repair.

BACKGROUND: Ischemic colitis after an open abdominal aortic aneurysm (AAA) repair remains a serious complication with a nationally reported rate of 1% to 6% in elective cases and up to 60% after an aneurysmal rupture. To prevent this serious complication, inferior mesenteric artery (IMA) replantation is performed at the discretion of the surgeon based on his or her intraoperative findings, despite the lack of clear evidence to support this practice. The purpose of this study was to determine whether replantation of the IMA reduces the risk of ischemic colitis and improves the overall outcome of AAA repair. METHODS: Patients who underwent open infrarenal AAA repair were identified in the multicenter American College of Surgeons National Surgical Quality Improvement Program Targeted AAA Database from 2012 to 2015. Emergency cases, patients with chronically occluded IMAs, ruptured aneurysms with evidence of hypotension, and patients requiring visceral revascularization were excluded. The remaining elective cases were divided into two groups: those with IMA replantation (IMA-R) and those with IMA ligation. We measured the 30-day outcomes including mortality, morbidity, and perioperative outcomes. A multivariable logistic regression model was used for data analysis, adjusting for clinically relevant covariates. RESULTS: We identified 2397 patients who underwent AAA repair between 2012 and 2015, of which 135 patients (5.6%) had ischemic colitis. After applying the appropriate exclusion criteria, there were 672 patients who were included in our study. This cohort was divided into two groups: 35 patients with IMA-R and 637 patients with IMA ligation. There were no major differences in preoperative comorbidities between the two groups. IMA-R was associated with increased mean operative time (319.7 ± 117.8 minutes vs 242.4 ± 109.3 minutes; P < .001). Examination of 30-day outcomes revealed patients with IMA-R had a higher rate of return to the operating room (20.0% vs 7.2%; P = .006), a higher rate of wound complications (17.1% vs 3.0%; P = .001), and a higher incidence of ischemic colitis (8.6% vs 2.4%; P = .027). There were no significant differences in mortality, pulmonary complications, or renal complications between the two groups. In multivariable analysis, IMA-R was a significant predictor of ischemic colitis and wound complications. CONCLUSIONS: These data suggest that IMA-R is not associated with protection from ischemic colitis after open AAA repair. The role of IMA-R remains to be identified.

Smooth muscle cell-specific matrix metalloproteinase 3 deletion reduces osteogenic transformation and medial artery calcification.

AIMS: Vascular calcification is highly prevalent in atherosclerosis, diabetes, and chronic kidney disease. It is associated with increased morbidity and mortality in patients with cardiovascular disease. Matrix metalloproteinase 3 (MMP-3), also known as stromelysin-1, is part of the large matrix metalloproteinase family. It can degrade extracellular matrix components of the arterial wall including elastin, which plays a central role in medial calcification. In this study, we sought to determine the role of MMP-3 in medial calcification. METHODS AND RESULTS: We found that MMP-3 was increased in rodent models of medial calcification as well as in vascular smooth muscle cells (SMCs) cultured in a phosphate calcification medium. It was also highly expressed in calcified tibial arteries in patients with peripheral arterial disease (PAD). Knockdown and inhibition of MMP-3 suppressed phosphate-induced SMC osteogenic transformation and calcification, whereas the addition of a recombinant MMP-3 protein facilitated SMC calcification. In an ex vivo organ culture model and a rodent model of medial calcification induced by vitamin D3, we found that MMP-3 deficiency significantly suppressed medial calcification in the aorta. We further found that medial calcification and osteogenic transformation were significantly reduced in SMC-specific MMP-3-deficient mice, suggesting that MMP-3 in SMCs is an important factor in this process. CONCLUSION: These findings suggest that MMP-3 expression in vascular SMCs is an important regulator of medial calcification and that targeting MMP-3 could provide a therapeutic strategy to reduce it and address its consequences in patients with PAD.