Julian Gunn

Interleukin-1 Receptor Antagonist Gene Polymorphism and Coronary Artery Disease

BACKGROUND Cytokine gene variations are contributory factors in inflammatory pathology. Allele frequencies of interleukin (IL)-1 cluster genes [IL-1A(-889), IL-1B(-511), IL-1B(+3953), IL-1RN Intron 2 VNTR] and tissue necrosis factor (TNF)-alpha gene [TNFA(-308)] were measured in healthy blood donors (healthy control subjects), patients with angiographically normal coronary arteries (patient control subjects), single-vessel coronary disease (SVD), and those with multivessel coronary disease (MVD). METHODS AND RESULTS Five hundred fifty-six patients attending for coronary angiography in Sheffield were studied: 130 patient control subjects, 98 SVD, and 328 MVD. Significant associations were tested in an independent population (London) of 350: 57 SVD, 191 MVD, and 102 control subjects. IL-1RN*2 frequency in Sheffield patient control subjects was the same as in 827 healthy control subjects. IL-1RN*2 was significantly overrepresented in Sheffield SVD patients (34% vs 23% in patient control subjects); IL-1RN*2 homozygotes in the SVD population (chi2 carriage=8.490, 1 df, P=0.0036). This effect was present though not quite significant in the London population (P=0. 0603). A summary trend test of the IL-1RN SVD genotype data for Sheffield and London showed a significant association with *2 (P=0. 0024). No significant effect of genotype at IL-1RN was observed in the Sheffield or London MVD populations. Genotype distribution analysis comparing the SVD and MVD populations at IL-1RN showed a highly significant trend (P=0.0007) with the use of pooled data. No significant associations were seen for the other polymorphisms. CONCLUSIONS IL-1RN*2 was significantly associated with SVD. A difference in genetic association between SVD and MVD was also apparent.

A collaborative systematic review and meta-analysis on 1278 patients undergoing percutaneous drug-eluting stenting for unprotected left main coronary artery disease ☆

BACKGROUND Cardiac surgery is the standard treatment for unprotected left main disease (ULM). Drug-eluting stent (DES) implantation has been recently reported in patients with ULM but with unclear results. We systematically reviewed outcomes of percutaneous DES implantation in ULM. METHODS Several databases were searched for clinical studies reporting on > or = 20 patients and > or = 6-month follow-up. The primary end point was major adverse cardiovascular events (MACEs; ie, death, myocardial infarction, or target vessel revascularization [TVR]) at the longest follow-up. Incidence and adjusted risk estimates were pooled with generic inverse variance random-effect methods (95% CIs). RESULTS From 823 initial citations, 16 studies were included (1278 patients, median follow-up 10 months). Eight were uncontrolled registries, 5 nonrandomized comparisons between DES and bare-metal stents and 3 nonrandomized comparisons between DES and CABG, with no properly randomized trial. Meta-analysis for DES-based PCI showed, at the longest follow-up, rates of 16.5% (11.7%-21.3%) MACE, 5.5% (3.4%-7.7%) death, and 6.5% (3.7%-9.2%) TVR. Comparison of DES versus bare-metal stent disclosed adjusted odds ratios for MACE of 0.34 (0.16-0.71), and DES versus CABG showed adjusted odds ratios for MACE plus stroke of 0.46 (0.24-0.90). Meta-regression showed that disease location predicted MACE (P = .001) and TVR (P = .020), whereas high-risk features predicted death (P = .027). CONCLUSIONS Clinical studies report apparently favorable early and midterm results in selected patients with ULM. However, given their limitations in validity and the inherent risk for DES thrombosis, results from randomized trials are still needed to definitely establish the role of DES implantation instead of the reference treatment, surgery.

Apoptosis and Cell Proliferation After Porcine Coronary Angioplasty

BACKGROUND Angioplasty initiates a number of responses in the vessel wall including cellular migration, proliferation, and matrix accumulation, all of which contribute to neointima formation and restenosis. Cellular homeostasis within a tissue depends on the balance between cell proliferation and apoptosis. METHODS AND RESULTS Profiles of apoptosis and proliferation were therefore examined in a porcine PTCA injury model over a 28-day period. Forty-two arteries from 21 pigs, harvested at the site of maximal injury at 1, 6, and 18 hours, and 3, 7, 14, and 28 days after PTCA, were examined (n=3 animals per time point). Uninjured arteries were used as controls. Apoptosis was demonstrated by the terminal uridine nick-end labeling (TUNEL) method, transmission electron microscopy (TEM), and DNA fragmentation. Cells traversing the cell cycle were identified by immunostaining for proliferating cell nuclear antigen (PCNA). Apoptosis was not detected in control vessels at all time points nor at 28 days after PTCA. Apoptotic cells were identified at all early time points with a peak at 6 hours (5.1+/-0.26%; compared to uninjured artery, P<0.001) and confirmed by characteristic DNA ladders and TEM findings. Regional analysis showed apoptosis within the media, adventitia, and neointima peaked at 18 hours, 6 hours, and 7 days after PTCA, respectively. In comparison, PCNA staining peaked at 3 days after PTCA (7.16+/-0.29%; compared to 1.78+/-0.08% PCNA-positive cells in the uninjured artery, P<0.001). Profiles of apoptosis and cell proliferation after PTCA were discordant in all layers of the artery except the neointima. These profiles also differed between traumatized and nontraumatized regions of the arterial wall. Immunostaining with cell-type specific markers and TEM analysis revealed that apoptotic cells included vascular smooth muscle cells (VSMCs), inflammatory cells, and adventitial fibroblasts. CONCLUSIONS These results suggest that the profile of apoptosis and proliferation after PTCA is regional and cell specific, and attempts to modulate either of these events for therapeutic benefit requires recognition of these differences.

Virtual fractional flow reserve from coronary angiography: modeling the significance of coronary lesions: results from the VIRTU-1 (VIRTUal Fractional Flow Reserve From Coronary Angiography) study.

OBJECTIVES The aim of this study was to develop a computer model that accurately predicts myocardial fractional flow reserve (FFR) from angiographic images alone, in patients with coronary artery disease. BACKGROUND Percutaneous coronary intervention (PCI) guided by FFR is superior to standard assessment alone. FFR-guided PCI results in improved clinical outcomes, a reduction in the number of stents implanted, and reduced cost. Currently FFR is used in few patients. A less invasive FFR would be a valuable tool. METHODS Nineteen patients with stable coronary artery disease awaiting elective PCI were studied. They underwent rotational coronary angiography. The FFR was measured, physiologically significant lesions were stented, and angiography and FFR were repeated. Three-dimensional arterial anatomy pre- and post-stenting was reconstructed offline. Generic boundary conditions for computational fluid dynamics analysis were applied. The virtual fractional flow reserve (vFFR) and measured fractional flow reserve (mFFR) values were compared. RESULTS Thirty-five matched anatomical and physiological datasets were obtained: 10 right coronary arteries (RCA) (5 pre- and post-stenting), and 12 left coronary arteries (LCA) (8 pre- and post-stenting). The computational fluid dynamics model predicted which lesions were physiologically significant (FFR <0.80) and which were not (FFR >0.80) with accuracy, sensitivity, specificity, positive and negative predictive values of 97%, 86%, 100%, 100%, and 97% respectively. On average, the vFFR values deviated from mFFR by ±0.06 (mean delta = 0.02, SD = 0.08). The vFFR and mFFR were closely correlated (r = 0.84). CONCLUSIONS We have developed a model of intracoronary physiology based upon a rotational coronary angiogram. Significant lesions were identified with 97% accuracy. The FFR was reliably predicted without the need for invasive measurements or inducing hyperemia.

Coronary stents: historical development, current status and future directions

INTRODUCTION Coronary angioplasty with stenting has revolutionized the treatment of coronary artery disease. This article describes the history of coronary angioplasty and stenting, reviews the contemporary stents and recommendations and highlights the on-going work and potential future directions. SOURCES OF DATA This review examined the data on coronary stents available in PubMed. AREAS OF AGREEMENT Coronary artery stenting is the treatment of choice for patients requiring coronary angioplasty. Stents, and particularly drug-eluting stents, reduce the risk of restenosis, but may be associated with the hazard of late stent thrombosis. Dual anti-platelet treatment is recommended for patients receiving coronary stents. AREAS OF CONTROVERSY The selection of stents for various lesions and patients and the duration of anti-platelet therapy remain debated areas. AREAS TIMELY FOR DEVELOPING RESEARCH There are on-going preclinical and clinical studies to develop better stent platforms, more biocompatible polymers, novel anti-proliferative and anti-platelet drugs, pro-healing stents and bioresorbable scaffolds.

Coronary artery stretch versus deep injury in the development of in-stent neointima

Objective: To investigate the relative importance of stent induced arterial stretch and deep injury to the development of in-stent neointima. Setting: Normal porcine coronary arteries Methods: 30 BiodivYsio stents (Biocompatibles) were deployed at a stent to artery ratio of 1.25:1 (a moderate injury) and harvested at 28 days. Multiple serial cross sections were analysed morphometrically and the neointimal areas were correlated with the type and degree of injury. Results: Arterial stretch occurred in 78% of struts (77% of sections) and produced moderate neointimal growth (neointimal area 1.93 (0.13) mm2). Deep injury (rupture of the internal elastic lamina) occurred in 20% of struts (23% of sections) and produced a 1.7-fold increase in neointimal area (3.33 (0.41) mm2) compared with stretch only (p = 0.0002). With even deeper injury (rupture of the external elastic lamina), there was a 2.6-fold increase in neointimal area (5.01 (0.48) mm2) compared with stretch only (p = 0.02). A new injury score, incorporating both stretch and deep injury, correlated with neointimal area (r = 0.60, p < 0.001). Conclusions: Stretch of the coronary artery in a stent is common, and a major contributor to neointima formation, even in the absence of deep injury. Deep injury is, however, a more potent stimulus to neointima formation than stretch. Greater degrees of stretch are associated with thicker neointima. Where neither deep injury nor stretch are seen, the stent has no effect upon the development of neointima.

The effect of interleukin-1 receptor antagonist therapy on markers of inflammation in non-ST elevation acute coronary syndromes: the MRC-ILA Heart Study

Aims Acute coronary syndromes (ACSs) are driven by inflammation within coronary plaque. Interleukin-1 (IL-1) has an established role in atherogenesis and the vessel-response to injury. ACS patients have raised serum markers of inflammation. We hypothesized that if IL-1 is a driving influence of inflammation in non-ST elevation ACS (NSTE-ACS), IL-1 inhibition would reduce the inflammatory response at the time of ACS. Methods and results A phase II, double-blinded, randomized, placebo-controlled, study recruited 182 patients with NSTE-ACS, presenting <48 h from onset of chest pain. Treatment was 1:1 allocation to daily, subcutaneous IL-1receptor antagonist (IL-1ra) or placebo for 14 days. Baseline characteristics were well matched. Treatment compliance was 85% at 7 days. The primary endpoint (area-under-the-curve for C-reactive protein over the first 7 days) was: IL-1ra group, 21.98 mg day/L (95%CI 16.31–29.64); placebo group, 43.5 mg day/L (31.15–60.75) (geometric mean ratio = 0.51 mg/L; 95%CI 0.32–0.79; P = 0.0028). In the IL-1ra group, 14-day achieved high-sensitive C-reactive protein (P < 0.0001) and IL-6 levels (P = 0.02) were lower than Day 1. Sixteen days after discontinuation of treatment (Day 30) high-sensitive C-reactive protein levels had risen again in the IL-1ra group [IL-1ra; 3.50 mg/L (2.65–4.62): placebo; 2.21 mg/L (1.67–2.92), P = 0.022]. MACE at Day 30 and 3 months was similar but at 1 year there was a significant excess of events in the IL-1ra group. Conclusion IL-1 drives C-reactive protein elevation at the time of NSTE-ACS. Following 14 days IL-1ra treatment inflammatory markers were reduced. These results show the importance of IL-1 as a target in ACS, but also indicate the need for additional studies with anti-IL-1 therapy in ACS to assess duration and safety. Clinical Trial Registration EUCTR: 2006-001767-31-GB: www.clinicaltrialsregister.eu/ctr-search/trial/2006-001767-31/GB.

The application of multiscale modelling to the process of development and prevention of stenosis in a stented coronary artery

The inherent complexity of biomedical systems is well recognized; they are multiscale, multiscience systems, bridging a wide range of temporal and spatial scales. While the importance of multiscale modelling in this context is increasingly recognized, there is little underpinning literature on the methodology and generic description of the process. The COAST (complex autonoma simulation technique) project aims to address this by developing a multiscale, multiscience framework, coined complex autonoma (CxA), based on a hierarchical aggregation of coupled cellular automata (CA) and agent-based models (ABMs). The key tenet of COAST is that a multiscale system can be decomposed into N single-scale CA or ABMs that mutually interact across the scales. Decomposition is facilitated by building a scale separation map on which each single-scale system is represented according to its spatial and temporal characteristics. Processes having well-separated scales are thus easily identified as the components of the multiscale model. This paper focuses on methodology, introduces the concept of the CxA and demonstrates its use in the generation of a multiscale model of the physical and biological processes implicated in a challenging and clinically relevant problem, namely coronary artery in-stent restenosis.

The Effect of Oligonucleotides to c-myb on Vascular Smooth Muscle Cell Proliferation and Neointima Formation After Porcine Coronary Angioplasty

Proto-oncogenes, including c-myb, are expressed early after vascular injury. The application of antisense oligodeoxynucleotides (AS-ODNs) against these genes inhibits cell proliferation and neointima formation in small animals and in peripheral arteries. The aim of this study was to investigate the specificity of action of AS-ODN-c-myb in vitro and to assess its effect, when delivered locally, on neointima formation after percutaneous transluminal coronary angioplasty (PTCA) in porcine coronary arteries. AS-ODN-c-myb inhibited the proliferation of vascular smooth muscle cells (VSMCs) in vitro in a dose-dependent manner. There was a corresponding reduction in steady state levels of c-myb mRNA and protein. Expression of another early gene, c-fos, was unaffected. S1 nuclease analysis demonstrated intact full-length AS-ODN-c-myb retrieved from VSMCs in culture after 12 hours. A range of ODNs, related and unrelated to c-myb, with and without a GGGG sequence, inhibited VSMC proliferation. Phosphorothioated AS-ODN-c-myb was 30 times less potent than unphosphorothioated AS-ODN-c-myb. PTCA induced porcine coronary artery neointima formation. c-myb mRNA was maximally induced 18 hours after injury. Unmodified AS-ODN-c-myb, sense-ODN-c-myb, saline, or nothing was delivered immediately after balloon dilatation via a double-skinned porous balloon (Transport, SciMed). Fluorescence-labeled AS-ODN-c-myb was deposited throughout the vessel wall. Mean maximum intima/media cross-sectional area 4 weeks after PTCA was reduced with AS-ODN-c-myb by 79% compared with saline (P < .05), 82% compared with sense-ODN-c-myb, and 63% compared with nothing (P < .10). Conclusions are as follows: (1) c-myb is expressed in VSMCs after vascular injury. (2) AS-ODN-c-myb is retained intact in VSMCs, reducing their proliferation in vitro in dose-dependent fashion, with reduction in c-myb mRNA and protein, whereas sense-ODN-c-myb is not. (3) A range of ODNs can reduce VSMC proliferation by a non-sequence-specific mechanism. (4) Phosphorothioate protection of antisense molecules may reduce their efficacy. (5) Local delivery of unmodified AS-ODN-c-myb via the Transport catheter reduces neointima formation after porcine PTCA. (6) Local delivery of fluid may exacerbate neointimal thickening.

Optimal Medical Therapy Improves Clinical Outcomes in Patients Undergoing Revascularization With Percutaneous Coronary Intervention or Coronary Artery Bypass Grafting

Background —There is a paucity of data on usage of optimal medical therapy (OMT) in patients with complex coronary artery disease undergoing revascularization with percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG) and its long-term prognostic significance. Methods and Results —SYNTAX is a multicenter randomized clinical trial of patients (n=1800) with complex coronary disease randomized to revascularization with PCI or CABG. Detailed drug history was collected for all the patients at discharge, 1-month, 6-month, 1-year, 3-year and 5-year follow-up. OMT was defined as the combination of at least one antiplatelet drug, statin, beta-blocker and angiotensin converting enzyme inhibitor/angiotensin receptor blocker. Five-year clinical outcomes were stratified by OMT and non-OMT. OMT was underused in patients treated with coronary revascularization, especially CABG. OMT was an independent predictor of survival. OMT was associated with a significant reduction in mortality (HR 0.64, 95% CI 0.48-0.85, p=0.002) and composite endpoint of death/MI/stroke (HR 0.73, 95% CI 0.58-0.92, p=0.007) at 5-year follow-up. The treatment effect with OMT (36% relative reduction in mortality over 5-year) was greater than the treatment effect of revascularization strategy (26% relative reduction in mortality with CABG versus PCI over 5-year). On stratified analysis, all the components of OMT were important for reducing adverse outcomes irrespective of revascularization strategy. Conclusions —Use of OMT remains low in patients with complex coronary disease requiring coronary intervention with PCI and even more with CABG. Lack of OMT is associated with adverse clinical outcomes. Targeted strategies to improve OMT usage in post revascularization patients are warranted. Clinical Trial Registration Information —www.clinicaltrials.gov. Identifier: [NCT00114972][1]. [1]: /lookup/external-ref?link_type=CLINTRIALGOV&access_num=NCT00114972&atom=%2Fcirculationaha%2Fearly%2F2015%2F02%2F24%2FCIRCULATIONAHA.114.013042.atomBackground— There is a paucity of data on the use of optimal medical therapy (OMT) in patients with complex coronary artery disease undergoing revascularization with percutaneous coronary intervention or coronary artery bypass grafting (CABG) and its long-term prognostic significance. Methods and Results— The Synergy Between Percutaneous Coronary Intervention With TAXUS and Cardiac Surgery (SYNTAX) trial is a multicenter, randomized, clinical trial of patients (n=1800) with complex coronary disease randomized to revascularization with percutaneous coronary intervention or CABG. Detailed drug history was collected for all patients at discharge and at the 1-month, 6-month, 1-year, 3-year, and 5-year follow-ups. OMT was defined as the combination of at least 1 antiplatelet drug, statin, &bgr;-blocker, and angiotensin-converting enzyme inhibitor/angiotensin receptor blocker. Five-year clinical outcomes were stratified by OMT and non-OMT. OMT was underused in patients treated with coronary revascularization, especially CABG. OMT was an independent predictor of survival. OMT was associated with a significant reduction in mortality (hazard ratio, 0.64; 95% confidence interval, 0.48–0.85; P=0.002) and composite end point of death/myocardial infarction/stroke (hazard ratio, 0.73; 95% confidence interval, 0.58–0.92; P=0.007) at the 5-year follow-up. The treatment effect with OMT (36% relative reduction in mortality over 5 years) was greater than the treatment effect of revascularization strategy (26% relative reduction in mortality with CABG versus percutaneous coronary intervention over 5 years). On stratified analysis, all the components of OMT were important for reducing adverse outcomes regardless of revascularization strategy. Conclusions— The use of OMT remains low in patients with complex coronary disease requiring coronary intervention with percutaneous coronary intervention and even lower in patients treated with CABG. Lack of OMT is associated with adverse clinical outcomes. Targeted strategies to improve OMT use in postrevascularization patients are warranted. Clinical Trial Registration— URL: http://www.clinicaltrials.gov. Unique identifier: NCT00114972.