Immediate versus staged complete revascularisation in patients presenting with acute coronary syndrome and multivessel coronary disease (BIOVASC): a prospective, open-label, non-inferiority, randomised trial.

BACKGROUND: In patients with acute coronary syndrome and multivessel coronary disease, complete revascularisation by percutaneous coronary intervention (PCI) is associated with improved clinical outcomes. We aimed to investigate whether PCI for non-culprit lesions should be attempted during the index procedure or staged. METHODS: This prospective, open-label, non-inferiority, randomised trial was done at 29 hospitals across Belgium, Italy, the Netherlands, and Spain. We included patients aged 18-85 years presenting with ST-segment elevation myocardial infarction or non-ST-segment elevation acute coronary syndrome and multivessel (ie, two or more coronary arteries with a diameter of 2·5 mm or more and ≥70% stenosis based on visual estimation or positive coronary physiology testing) coronary artery disease with a clearly identifiable culprit lesion. A web-based randomisation module was used to randomly assign patients (1:1), with a random block size of four to eight, stratified by study centre, to undergo immediate complete revascularisation (PCI of the culprit lesion first, followed by other non-culprit lesions deemed to be clinically significant by the operator during the index procedure) or staged complete revascularisation (PCI of only the culprit lesion during the index procedure and PCI of all non-culprit lesions deemed to be clinically significant by the operator within 6 weeks after the index procedure). The primary outcome was the composite of all-cause mortality, myocardial infarction, any unplanned ischaemia-driven revascularisation, or cerebrovascular events at 1 year after the index procedure. Secondary outcomes included all-cause mortality, myocardial infarction, and unplanned ischaemia-driven revascularisation at 1 year after the index procedure. Primary and secondary outcomes were assessed in all randomly assigned patients by intention to treat. Non-inferiority of immediate to staged complete revascularisation was considered to be met if the upper boundary of the 95% CI of the hazard ratio (HR) for the primary outcome did not exceed 1·39. This trial is registered with ClinicalTrials.gov, NCT03621501. FINDINGS: Between June 26, 2018, and Oct 21, 2021, 764 patients (median age 65·7 years [IQR 57·2-72·9] and 598 [78·3%] males) were randomly assigned to the immediate complete revascularisation group and 761 patients (median age 65·3 years [58·6-72·9] and 589 [77·4%] males) were randomly assigned to the staged complete revascularisation group, and were included in the intention-to-treat population. The primary outcome at 1 year occurred in 57 (7·6%) of 764 patients in the immediate complete revascularisation group and in 71 (9·4%) of 761 patients in the staged complete revascularisation group (HR 0·78, 95% CI 0·55-1·11, pnon-inferiority=0·0011). There was no difference in all-cause death between the immediate and staged complete revascularisation groups (14 [1·9%] vs nine [1·2%]; HR 1·56, 95% CI 0·68-3·61, p=0·30). Myocardial infarction occurred in 14 (1·9%) patients in the immediate complete revascularisation group and in 34 (4·5%) patients in the staged complete revascularisation group (HR 0·41, 95% CI 0·22-0·76, p=0·0045). More unplanned ischaemia-driven revascularisations were performed in the staged complete revascularisation group than in the immediate complete revascularisation group (50 [6·7%] patients vs 31 [4·2%] patients; HR 0·61, 95% CI 0·39-0·95, p=0·030). INTERPRETATION: In patients presenting with acute coronary syndrome and multivessel disease, immediate complete revascularisation was non-inferior to staged complete revascularisation for the primary composite outcome and was associated with a reduction in myocardial infarction and unplanned ischaemia-driven revascularisation. FUNDING: Erasmus University Medical Center and Biotronik.

Stent expansion in calcified coronary chronic total occlusions: The impact of different stent platforms.

OBJECTIVES: To evaluate the stent expansion of the durable-polymer Zotarolimus-eluting stent (dp-ZES), the durable-polymer Everolimus-eluting stent (dp-EES), and the bioabsorbable-polymer Sirolimus-eluting stent (bp-SES) in calcified coronary chronic total occlusions (CTO). BACKGROUND: The newer generation stents with ultrathin struts might raise concerns regarding reduced radial strength and higher stent recoil (SR) when implanted in calcified CTOs. METHODS: Between January 2017 and June 2021 consecutive patients with CTO undergoing percutaneous coronary intervention with dp-ZES, dp-EES, or bp-SES were evaluated. The analysis was performed in calcific and in noncalcific CTOs. Quantitative coronary angiography analysis was used to assess diameter stenosis (DS), absolute and relative SR, absolute and relative focal SR, absolute and relative balloon deficit (BD), and absolute and relative focal BD. The primary endpoint was DS. RESULTS: A total of 213 CTOs were evaluated, 115 calcific CTOs (dp-ZES:25, dp-EES:29, bp-SES:61) and 98 non-calcific CTOs (dp-ZES:41, dp-EES:11, bp-SES:46). In calcific CTOs, residual DS was lower in dp-ZES than in dp-EES and bp-SES (-1.00% [-6.50-6.50] vs. 13.00% [7.0-19.00] vs. 15.00% [5.00-20.00]; p < 0.001). Dp-ZES was also an independent predictor of residual DS ≤ 10% (OR 11.34, 95% CI 2.6-49.43, p = 0.001). Absolute and relative focal SR and absolute and relative SR were similar between dp-ZES, dp-EES, and bp-SES (p = 0.913, p = 0.890, p = 0.518, p = 0.426, respectively). In noncalcified CTOs, the residual DS was similar in the three groups (p = 0.340). High relative focal SR was less frequent in dp-ZES than in dp-EES and in bp-SES (19.5% vs. 54.5% vs. 37.0%; p < 0.048). CONCLUSIONS: The three stent platforms demonstrated an overall low residual DS when implanted in CTOs. However, dp-ZES was associated with the lowest residual DS and identified as independent predictor of residual DS ≤ 10% in patients with calcific CTOs. Dp-ZES was associated with a lower incidence of high relative focal stent recoil, in noncalcific CTOs. Balloon deficit might be considerate as a surrogate for stent expansion in calcified CTOs.

Culprit lesion plaque characterization and thrombus grading by high-definition intravascular ultrasound in patients with ST-segment elevation myocardial infarction.

BACKGROUND: Dedicated prospective studies investigating high-definition intravascular ultrasound (HD-IVUS)-guided primary percutaneous coronary intervention (PCI) are lacking. The aim of this study was to qualify and quantify culprit lesion plaque characteristics and thrombus using HD-IVUS in patients presenting with ST-segment elevation myocardial infarction (STEMI). METHODS: The SPECTRUM study is a prospective, single-center, observational cohort study investigating the impact of HD-IVUS-guided primary PCI in 200 STEMI patients (NCT05007535). The first 100 study patients with a de novo culprit lesion and a per-protocol mandated preintervention pullback directly after vessel wiring were subject to a predefined imaging analysis. Culprit lesion plaque characteristics and different thrombus types were assessed. An IVUS-derived thrombus score, including a 1-point adjudication for a long total thrombus length, long occlusive thrombus length, and large maximum thrombus angle, was developed to differentiate between low (0-1 points) and high (2-3 points) thrombus burden. Optimal cut-off values were obtained using receiver operating characteristic curves. RESULTS: The mean age was 63.5 (±12.1) years and 69 (69.0%) patients were male. The median culprit lesion length was 33.5 (22.8-38.9) mm. Plaque rupture and convex calcium were appreciated in 48 (48.0%) and 10 (10.0%) patients, respectively. Thrombus was observed in 91 (91.0%) patients (acute thrombus 3.3%; subacute thrombus 100.0%; organized thrombus 22.0%). High IVUS-derived thrombus burden was present in 37/91 (40.7%) patients and was associated with higher rates of impaired final thrombolysis in myocardial infarction flow (grade 0-2) (27.0% vs. 1.9%, p < 0.001). CONCLUSIONS: HD-IVUS in patients presenting with STEMI allows detailed culprit lesion plaque characterization and thrombus grading that may guide tailored PCI.

Optical coherence tomography-derived predictors of stent expansion in calcified lesions.

BACKGROUND: Severe coronary artery calcification is associated with stent underexpansion and subsequent stent failure. AIMS: We aimed to identify optical coherence tomography (OCT)-derived predictors of absolute (minimal stent area [MSA]) and relative stent expansion in calcified lesions. METHODS: This retrospective cohort study included patients who underwent percutaneous coronary intervention (PCI) with OCT assessment before and after stent implantation between May 2008 and April 2022. Pre-PCI OCT was used to assess calcium burden and post-PCI OCT was used to assess absolute and relative stent expansion. RESULTS: A total of 361 lesions in 336 patients were analyzed. Target lesion calcification (defined as OCT-detected maximum calcium angle ≥ 30°) was present in 242 (67.0%) lesions. Following PCI, median MSA was 5.37 mm2 in calcified lesions and 6.24 mm2 in noncalcified lesions (p < 0.001). Median stent expansion was 78% in calcified lesions and 83% in noncalcified lesions (p = 0.325). In the subset of calcified lesions, average stent diameter, preprocedural minimal lumen area, and total calcium length were independent predictors of MSA in multivariable analysis (mean difference 2.69 mm2 /mm2 , 0.52 mm2 /mm, and -0.28 mm2 /5 mm, respectively, all p < 0.001). Total stent length was the only independent predictor of relative stent expansion (mean difference -0.465% per mm, p < 0.001). Calcium angle, thickness, and the presence of nodular calcification were not significantly associated with MSA or stent expansion in multivariable analyses. CONCLUSION: Calcium length appeared to be the most important OCT-derived predictor of MSA, whereas stent expansion was mainly determined by total stent length.

Initial experience with orbital atherectomy in a tertiary centre in the Netherlands.

BACKGROUND: In January 2021, the Diamondback 360 orbital atherectomy (OA) system received CE mark approval and became available in Europe. The first procedure in Europe was performed at the Thoraxcenter, Erasmus Medical Center, Rotterdam, the Netherlands. AIMS: To report the procedural safety and efficacy of the initial experience with OA in a tertiary care institution in the Netherlands. METHODS: Patients with de novo severely calcified coronary artery disease who were treated with intended invasive imaging-guided OA were included in a prospective single-centre registry. Device success, defined as less than 50% stenosis after OA, and procedural success, defined as successful stent implantation with less than 50% residual stenosis, were evaluated. Calcium debulking effects were assessed by invasive imaging. Safety was assessed up to 30 days after the index procedure. RESULTS: Between February 2021 and June 2021, 29 patients with a total of 39 coronary arteries underwent OA. Target lesions were heavily calcified with a mean length of 32 mm and a calcium arc of 320 degrees. Invasive imaging was applied in all but one patient and 36 vessels. Superficial sanding was observed in almost all vessels (90%) and fracturing of deeper medial calcium in more than half of the vessels (63%), with a device success of 66% and procedural success of 94%. The mean stent symmetry index was 0.84, indicating good circular stent expansion. No primary safety events occurred during 30 days of follow-up. CONCLUSION: Our initial experience with OA for heavily calcified coronary lesions demonstrated favourable debulking effects and plaque modification, with high procedural success and clinical safety.

Elastic stent recoil in coronary total occlusions: Comparison of durable-polymer zotarolimus eluting stent and ultrathin strut bioabsorbable-polymer sirolimus eluting stent.

OBJECTIVES: To compare stent recoil (SR) of the thin-strut durable-polymer Zotarolimus-eluting stent (dp-ZES) and the ultrathin-strut bioabsorbable-polymer Sirolimus-eluting stent (bp-SES) in chronic total occlusions (CTOs) and to investigate the predictors of high SR in CTOs. BACKGROUND: Newer ultrathin drug eluting stent might be associated with lower radial force and higher elastic recoil due to the thinner strut design, possibly impacting on the rate of in-stent restenosis and thrombosis. METHODS: Between January 2017 and November 2019, consecutive patients with CTOs undergoing percutaneous coronary intervention were evaluated. Only patients treated with dp-ZES or bp-SES were included and stratified accordingly. Quantitative coronary angiography analysis was used to assess absolute SR, relative SR, absolute focal SR, relative focal SR, high absolute, and high relative focal SR. RESULTS: A total of 128 lesions (67 treated with dp-ZES and 61 with bp-SES) in 123 patients were analyzed. Between bp-SES and dp-ZES no differences were found in absolute SR (p = .188), relative SR (p = .138), absolute focal SR (p = .069), and relative focal SR (p = .064). High absolute and high relative focal SR occurred more frequently in bp-SES than in dp-ZES (p = .004 and p = .015). Bp-SES was a predictor of high absolute focal SR (Odds ratio [OR] 3.29, 95% confidence interval [CI] 1.50-7.22, p = .003]. High-pressure postdilation and bp-SES were predictors of high relative focal SR (OR 2.22, 95% CI 1.01-4.86, p = .047; OR 2.74, 95% CI 1.24-6.02, p = .012, respectively). CONCLUSIONS: Both stents showed an overall low SR. However, ultra-thin strut bp-SES was a predictor of high absolute and high relative focal SR.

Diagnostic accuracy of angiography-based vessel fractional flow reserve after chronic coronary total occlusion recanalization.

BACKGROUND: Angiography-based vessel fractional flow reserve (vFFR) demonstrated a strong correlation with invasive fractional flow reserve (FFR) in both a pre- and post-percutaneous coronary intervention (PCI) setting. However, the role of vFFR and its correlation with post-PCI FFR in chronic coronary occlusions (CTO) has not been evaluated yet. We sought to investigate the diagnostic performance of post-PCI vFFR with post-PCI FFR as a reference in patients undergoing successful CTO PCI. METHODS: Between March 2016 and April 2020, a total of 80 patients from the FFR-SEARCH (prospective registry) and FFR REACT (randomized controlled trial) studies underwent successful CTO recanalization with post-PCI FFR measurements. RESULTS: A total of 50 patients (median age 66 (interquartile range [IQR]: 56-74) years, 76% were male) were eligible for the analysis. Median post-PCI FFR was 0.89 (IQR: 0.84-0.94), while median post-PCI vFFR was 0.91 (IQR: 0.85-0.94) (p 0.10). Suboptimal physiological results, defined as FFR and vFFR <0.90, were identified in 26 (52%) and in 21 (42%) patients, respectively. A strong correlation (r = 0.82) was found between vFFR and FFR with a mean bias of 0.013 ± 0.051. Receiver-operating characteristics curve analysis revealed an excellent accuracy of vFFR in predicting FFR <0.90 (area under the curve: 0.97; 95% confidence interval: 0.93-1.00). CONCLUSION: Post-PCI vFFR shows a good correlation with post-PCI FFR and a high diagnostic accuracy for post-PCI FFR ≤0.90 in patients undergoing successful PCI of a CTO lesion.

Impact of thrombus burden on long-term clinical outcomes in patients with either anterior or non-anterior ST-segment elevation myocardial infarction.

Large thrombus burden (LTB) during ST-segment elevation myocardial infarction (STEMI) could translate into worse clinical outcomes. The impact of a LTB in terms of long-term clinical outcomes on different myocardial infarct territories has not yet been fully evaluated. From April 2002 to December 2004, consecutive patients with STEMI undergoing percutaneous coronary intervention with drug eluting stent were evaluated. The study sample was stratified in two groups: anterior STEMI and non-anterior STEMI. LTB was considered as a thrombus larger than or equal to 2-vessel diameters, and small thrombus burden less than 2-vessel diameters. Major adverse cardiac events (MACE) were evaluated at 10-year and survival data were collected up to 15-year. A total of 812 patients were evaluated, 6 patients were excluded due to inadequate angiographic images, 410 (50.9%) had an anterior STEMI and 396 (49.1%) a non-anterior STEMI. Patients with LTB had higher rates of 10-year mortality (aHR 2.27, 95%CI 1.42-3.63; p = 0.001) and 10-year MACE (aHR 1.46, 95%CI 1.03-2.08; p = 0.033) in anterior STEMI, but not in non-anterior STEMI (aHR 0.78, 95%CI 0.49-1.24; p = 0.298; aHR 0.71, 95%CI 0.50-1.02; p = 0.062). LTB was associated with increased 30-day mortality (aHR 5.60, 95%CI 2.49-12.61; p < 0.001) and 30-day MACE (aHR 2.72, 95%CI 1.45-5.08; p = 0.002) in anterior STEMI, but not in non-anterior STEMI (aHR 0.39, 95%CI 0.15-1.06; p = 0.066; aHR 0.67, 95%CI 0.31-1.46; p = 0.316). Beyond 30-day, LTB had no impact on mortality and MACE in both groups. In anterior STEMI, LTB is associated with worse long-term clinical outcomes, this effect was driven by early events.

Percutaneous complete revascularization strategies using sirolimus-eluting biodegradable polymer-coated stents in patients presenting with acute coronary syndrome and multivessel disease: Rationale and design of the BIOVASC trial.

BACKGROUND: Complete revascularization in patients with an acute coronary syndrome and multivessel disease is superior compared to culprit-only treatment. However, it is unknown whether direct complete or staged complete revascularization should be pursued. METHODS: The BIOVASC study is an investigator-initiated, prospective, multicenter, randomized, 2-arm, international, open-label, noninferiority trial. We will randomize 1,525 patients 1:1 to immediate complete revascularization (experimental arm) or culprit-only plus staged complete revascularization (control arm). Patients will be enrolled in approximately 30 sites in Belgium, Italy, the Netherlands, and Spain. The primary end point is a composite of all-cause mortality, nonfatal myocardial infarction, any unplanned ischemia-driven revascularization (excluding staged procedures in the control arm at the predetermined time), and cerebrovascular events (MACCE) at 1 year post index procedure. CONCLUSIONS: The BIOVASC study aims to further refine the treatment algorithm for acute coronary syndrome patients with multivessel disease in terms of optimal timing for complete revascularization (Clinicaltrials.gov NCT03621501).

Effect of shear stress alteration on atherosclerotic plaque vulnerability in cholesterol-fed rabbits.

Previously, we created an experimental murine model for the induction of vulnerable plaque (VP). Although this murine model offers the opportunity to study the different molecular biological pathways that regulate plaque destabilization, the size of the animals severely limits the use of the model for in vivo diagnostics and percutaneous interventions. This study aimed to create a VP model in the rabbit, based on the murine model, to aid the assessment and development of novel diagnostic and interventional tools. New Zealand white rabbits were fed on a 2% cholesterol diet. After 1 week, a shear stress-altering device was implanted around the right carotid artery. Twelve weeks after cast placement, the carotid artery was isolated and processed for (immuno-)histological analysis to evaluate the presence of a VP phenotype. Atherosclerotic plaques with high lipid and macrophage content, low vascular smooth muscle cell content and intimal neovascularization were located upstream and downstream of the cast. The plaques lacked a significant necrotic core. In conclusion, we were able to create atherosclerotic plaques with a phenotype beyond that of a fatty streak, with a high percentage of lipids and macrophages, a thick cap with some vascular smooth muscle cells and neovascularization. However, as there was only a small necrotic core, the overall phenotype seems less vulnerable as compared to the thin fibrous cap atheroma in patients.

Acute Isolated Right Ventricular Infarction.

The electrocardiogram is universally used to diagnose ST-segment elevation myocardial infarction and serves as guidance for the interventional cardiologist to identify the acute thrombotic lesion. However, this case illustrates that the electrocardiogram can also be deceiving.

Timing of Complete Revascularization Stratified by Index Presentation During On- and Off-Hours.

Recent trials suggested immediate complete revascularization (ICR) as a safe alternative to staged complete revascularization (SCR), but the impact of the respective percutaneous coronary intervention strategies between on- versus off-hours is unclear. On-hours was defined as an index revascularization performed between 8:00 a.m. and 6:00 p.m., Monday to Friday, or else the procedure was defined as performed during off-hours. The primary end point consisted of a composite of all-cause mortality, myocardial infarction, unplanned ischemia-driven revascularization, and cerebrovascular events at 1-year follow-up. We used Cox regression models to relate randomized treatment with study end points. We evaluated multiplicative and additive interactions between on- versus off-hours and randomized treatment. The BIOVASC (Percutaneous Complete Revascularization Strategies Using Sirolimus Eluting Biodegradable Polymer Coated Stents in Patients Presenting With Acute Coronary Syndromes and Multivessel Disease) trial enrolled 1,097 and 428 patients during on- and off-hours, respectively. Patients randomized during off-hours were more likely to present with ST-segment elevation myocardial infarction (66.4% vs 29.5%, p <0.001). The composite primary outcome occurred in 8.4% and 10.1% of patients randomized to ICR and SCR, respectively, during on-hours (hazard ratio 0.80, 95% confidence interval 0.54 to 1.19). During off-hours, the primary composite outcome occurred in 5.4% and 7.7% in ICR and SCR (0.69, 95% confidence interval 0.32 to 1.46) with no evidence of a differential effect (interaction pmultiplicative = 0.70, padditive = 0.56). No differential effect was found between treatment allocation and on- versus off-hours in any of the secondary outcomes. In conclusion, no differential treatment effect was found when comparing ICR versus SCR in patients presenting with acute coronary syndrome and multivessel disease during on- or off-hours.

Immediate or staged complete revascularisation in patients presenting with acute coronary syndrome by number of diseased vessels: a substudy of the BIOVASC randomised trial.

BACKGROUND: In patients presenting with acute coronary syndrome (ACS), the number of diseased vessels may affect the efficacy of a complete revascularisation strategy. AIMS: The authors sought to evaluate the safety and efficacy of immediate complete revascularisation (ICR) and staged complete revascularisation (SCR) in patients presenting with ACS stratified by the number of diseased vessels. METHODS: In this prespecified analysis of the BIOVASC trial, ICR was compared with SCR in patients with two-vessel disease (2VD) or three-vessel disease (3VD). The primary endpoint was a composite of all-cause mortality, myocardial infarction (MI), any unplanned ischaemia-driven revascularisation or cerebrovascular events at 1 year after the index procedure. Comparisons were performed using Cox regression. RESULTS: A total of 1,525 patients were enrolled in the BIOVASC trial, of whom 1,177 presented with 2VD and 265 with 3VD. In the 2VD group, 613 patients were assigned to ICR and 564 to SCR. In the 3VD group, 117 patients were assigned to ICR and 148 to SCR. ICR and SCR led to similar results in both the 2VD (hazard ratio [HR] 0.76, 95% confidence interval [CI]: 0.50-1.13; p=0.18) and 3VD groups (HR 0.79, 95% CI: 0.39-1.59; p=0.51) (pinteraction=0.91) in terms of the primary endpoint. ICR was associated with a lower rate of MI in patients with 3VD (HR 0.21, 95% CI: 0.046-0.93; p=0.04) (pinteraction=0.30). CONCLUSIONS: ICR might be an option in patients presenting with extensive 3VD and might be associated with a lower rate of myocardial infarction compared with SCR.

Timing of Complete Multivessel Revascularization in Patients Presenting With Non-ST-Segment Elevation Acute Coronary Syndrome.

BACKGROUND: Complete revascularization of the culprit and all significant nonculprit lesions in patients with non-ST-segment elevation acute coronary syndrome (NSTE-ACS) and multivessel disease (MVD) reduces major adverse cardiac events, but optimal timing of revascularization remains unclear. OBJECTIVES: This study aims to compare immediate complete revascularization (ICR) and staged complete revascularization (SCR) in patients presenting with NSTE-ACS and MVD. METHODS: This prespecified substudy of the BIOVASC (Percutaneous Complete Revascularization Strategies Using Sirolimus Eluting Biodegradable Polymer Coated Stents in Patients Presenting With Acute Coronary Syndrome and Multivessel Disease) trial included patients with NSTE-ACS and MVD. Risk differences of the primary composite outcome of all-cause mortality, myocardial infarction (MI), unplanned ischemia-driven revascularization (UIDR), or cerebrovascular events and its individual components were compared between ICR and SCR at 1 year. RESULTS: The BIOVASC trial enrolled 1,525 patients; 917 patients presented with NSTE-ACS, of whom 459 were allocated to ICR and 458 to SCR. Incidences of the primary composite outcome were similar in the 2 groups (7.9% vs 10.1%; risk difference 2.2%; 95% CI: -1.5 to 6.0; P = 0.15). ICR was associated with a significant reduction of MIs (2.0% vs 5.3%; risk difference 3.3%; 95% CI: 0.9 to 5.7; P = 0.006), which was maintained after exclusion of procedure-related MIs occurring during the index or staged procedure (2.0% vs 4.4%; risk difference 2.4%; 95% CI: 0.1 to 4.7; P = 0.032). UIDRs were also reduced in the ICR group (4.2% vs 7.8%; risk difference 3.5%; 95% CI: 0.4 to 6.6; P = 0.018). CONCLUSIONS: ICR is safe in patients with NSTE-ACS and MVD and was associated with a reduction in MIs and UIDRs at 1 year.

Endothelial cell-specific FGD5 involvement in vascular pruning defines neovessel fate in mice.

BACKGROUND: New vessel formation contributes to organ development during embryogenesis and tissue repair in response to mechanical damage, inflammation, and ischemia in adult organisms. Early angiogenesis includes formation of an excessive primitive network that needs to be reorganized into a secondary vascular network with higher hierarchical structure. Vascular pruning, the removal of aberrant neovessels by apoptosis, is a vital step in this process. Although multiple molecular pathways for early angiogenesis have been identified, little is known about the genetic regulators of secondary network development. METHODS AND RESULTS: Using a transcriptomics approach, we identified a new endothelial specific gene named FYVE, RhoGEF, and PH domain-containing 5 (FGD5) that plays a crucial role in vascular pruning. Loss- and gain-of-function studies demonstrate that FGD5 inhibits neovascularization, indicated by in vitro tube-formation, aortic-ring, and coated-bead assays and by in vivo coated-bead plug assays and studies in the murine retina model. FGD5 promotes apoptosis-induced vaso-obliteration via induction of the hey1-p53 pathway by direct binding and activation of cdc42. Indeed, FGD5 correlates with apoptosis in endothelial cells during vascular remodeling and was linked to rising p21(CIP1) levels in aging mice. CONCLUSION: We have identified FGD5 as a novel genetic regulator of vascular pruning by activation of endothelial cell-targeted apoptosis.

Ets2 determines the inflammatory state of endothelial cells in advanced atherosclerotic lesions.

RATIONALE: Neovascularization is required for embryonic development and plays a central role in diseases in adults. In atherosclerosis, the role of neovascularization remains to be elucidated. In a genome-wide microarray-screen of Flk1+ angioblasts during murine embryogenesis, the v-ets erythroblastosis virus E26 oncogene homolog 2 (Ets2) transcription factor was identified as a potential angiogenic factor. OBJECTIVES: We assessed the role of Ets2 in endothelial cells during atherosclerotic lesion progression toward plaque instability. METHODS AND RESULTS: In 91 patients treated for carotid artery disease, Ets2 levels showed modest correlations with capillary growth, thrombogenicity, and rising levels of tumor necrosis factor-α (TNFα), monocyte chemoattractant protein 1, and interleukin-6 in the atherosclerotic lesions. Experiments in ApoE(-/-) mice, using a vulnerable plaque model, showed that Ets2 expression was increased under atherogenic conditions and was augmented specifically in the vulnerable versus stable lesions. In endothelial cell cultures, Ets2 expression and activation was responsive to the atherogenic cytokine TNFα. In the murine vulnerable plaque model, overexpression of Ets2 promoted lesion growth with neovessel formation, hemorrhaging, and plaque destabilization. In contrast, Ets2 silencing, using a lentiviral shRNA construct, promoted lesion stabilization. In vitro studies showed that Ets2 was crucial for TNFα-induced expression of monocyte chemoattractant protein 1, interleukin-6, and vascular cell adhesion molecule 1 in endothelial cells. In addition, Ets2 promoted tube formation and amplified TNFα-induced loss of vascular endothelial integrity. Evaluation in a murine retina model further validated the role of Ets2 in regulating vessel inflammation and endothelial leakage. CONCLUSIONS: We provide the first evidence for the plaque-destabilizing role of Ets2 in atherosclerosis development by induction of an intraplaque proinflammatory phenotype in endothelial cells.

Mast cells induce vascular smooth muscle cell apoptosis via a toll-like receptor 4 activation pathway.

OBJECTIVE: Activated mast cells (MCs) release chymase, which can induce vascular smooth muscle cell (VSMC) apoptosis leading to plaque destabilization. Because the mechanism through which MCs release chymase in atherosclerosis is unknown, we studied whether MC-associated VSMC apoptosis is regulated by toll-like receptor 4 (TLR4) signaling. METHODS AND RESULTS: Local recruitment and activation of MCs reduced VSMC content specifically in the cap region of vulnerable plaques in apolipoprotein E knockout mice. Cotreatment with the TLR4 antagonist Bartonella quintana lipopolysaccharide prevented this VSMC loss, suggesting an important role for TLR4 signaling in MC-induced VSMC apoptosis. Coculture of VSMCs with MCs activated by the TLR4 agonist Escherichia coli lipopolysaccharide increased VSMC apoptosis. Apoptosis was inhibited by TLR4 and chymase blockers, indicating that TLR4 signaling is involved in chymase release in MCs. This pathway was mediated via interleukin-6 because interleukin-6 promoted MC-associated VSMC apoptosis, which was inhibited by blocking chymase release. In addition, TLR4 activation in MCs induced interleukin-6 production, which was reduced by preincubation with either B. quintana lipopolysaccharide or an anti-TLR4 antibody. CONCLUSIONS: We show that MCs promote VSMC apoptosis in vivo. In addition, TLR4 signaling is important in chymase release in MCs and, therefore, in plaque destabilization by regulating VSMC apoptosis.