Background Medical Therapy and Clinical Outcomes From the VICTORIA Trial

BACKGROUND

We examined whether the primary composite outcome (cardiovascular death or heart failure hospitalization) was related to differences in background use and dosing of guideline-directed medical therapy in patients with heart failure with reduced ejection fraction enrolled in VICTORIA (Vericiguat Global Study in Subjects with Heart Failure with Reduced Ejection Fraction), a randomized trial of vericiguat versus placebo.

METHODS

We evaluated the adherence to guideline use of angiotensin-converting enzyme inhibitors, angiotensin-receptor blockers, angiotensin receptor-neprilysin inhibitors, beta-blockers, and mineralocorticoid receptor antagonists. We assessed basic adherence; indication-corrected adherence accounting for guideline indications and contraindications; and dose-corrected adherence (indication-corrected adherence+≥50% of drug dose target). Associations between study treatment and the primary composite outcome according to the adherence to guidelines were assessed using multivariable adjustment; adjusted hazard ratios with 95% CIs and Pinteraction are reported.

RESULTS

Of 5050 patients, 5040 (99.8%) had medication data at baseline. For angiotensin-converting enzyme inhibitor, angiotensin-receptor blockers, and angiotensin receptor-neprilysin inhibitors, basic adherence to guidelines was 87.4%, indication-corrected was 95.7%, and dose-corrected was 50.9%. For beta-blockers, basic adherence was 93.1%, indication-corrected was 96.2%, and dose-corrected was 45.4%. For mineralocorticoid receptor antagonists, basic adherence was 70.3%, indication-corrected was 87.1%, and dose-corrected was 82.2%. For triple therapy (angiotensin-converting enzyme inhibitors, angiotensin-receptor blockers, or angiotensin receptor-neprilysin inhibitors+beta-blocker+mineralocorticoid receptor antagonist), basic adherence was 59.7%, indication-corrected was 83.3%, and dose-corrected was 25.5%. Using basic or dose-corrected adherence, the treatment effect of vericiguat was consistent across adherence to guidelines groups, with or without multivariable adjustment with no treatment heterogeneity.

CONCLUSIONS

Patients in VICTORIA were well treated with heart failure with reduced ejection fraction medications. The efficacy of vericiguat was consistent across background therapy with very high adherence to guidelines accounting for patient-level indications, contraindications, and tolerance.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT02861534.

Phase 3 Trial of Sotatercept for Treatment of Pulmonary Arterial Hypertension

BACKGROUND

Pulmonary arterial hypertension is a progressive disease involving proliferative remodeling of the pulmonary vessels. Despite therapeutic advances, the disease-associated morbidity and mortality remain high. Sotatercept is a fusion protein that traps activins and growth differentiation factors involved in pulmonary arterial hypertension.

METHODS

We conducted a multicenter, double-blind, phase 3 trial in which adults with pulmonary arterial hypertension (World Health Organization [WHO] functional class II or III) who were receiving stable background therapy were randomly assigned in a 1:1 ratio to receive subcutaneous sotatercept (starting dose, 0.3 mg per kilogram of body weight; target dose, 0.7 mg per kilogram) or placebo every 3 weeks. The primary end point was the change from baseline at week 24 in the 6-minute walk distance. Nine secondary end points, tested hierarchically in the following order, were multicomponent improvement, change in pulmonary vascular resistance, change in N-terminal pro-B-type natriuretic peptide level, improvement in WHO functional class, time to death or clinical worsening, French risk score, and changes in the Pulmonary Arterial Hypertension-Symptoms and Impact (PAH-SYMPACT) Physical Impacts, Cardiopulmonary Symptoms, and Cognitive-Emotional Impacts domain scores; all were assessed at week 24 except time to death or clinical worsening, which was assessed when the last patient completed the week 24 visit.

RESULTS

A total of 163 patients were assigned to receive sotatercept and 160 to receive placebo. The median change from baseline at week 24 in the 6-minute walk distance was 34.4 m (95% confidence interval [CI], 33.0 to 35.5) in the sotatercept group and 1.0 m (95% CI, -0.3 to 3.5) in the placebo group. The Hodges-Lehmann estimate of the difference between the sotatercept and placebo groups in the change from baseline at week 24 in the 6-minute walk distance was 40.8 m (95% CI, 27.5 to 54.1; P<0.001). The first eight secondary end points were significantly improved with sotatercept as compared with placebo, whereas the PAH-SYMPACT Cognitive-Emotional Impacts domain score was not. Adverse events that occurred more frequently with sotatercept than with placebo included epistaxis, dizziness, telangiectasia, increased hemoglobin levels, thrombocytopenia, and increased blood pressure.

CONCLUSIONS

In patients with pulmonary arterial hypertension who were receiving stable background therapy, sotatercept resulted in a greater improvement in exercise capacity (as assessed by the 6-minute walk test) than placebo. (Funded by Acceleron Pharma, a subsidiary of MSD; STELLAR ClinicalTrials.gov number, NCT04576988.).

Medical Therapy During Hospitalization for Heart Failure with Reduced Ejection Fraction: The VICTORIA Registry: Medical Therapy During Hospitalization for HFrEF

BACKGROUND

For patients hospitalized for heart failure with reduced ejection fraction (HFrEF), guidelines recommend optimization of medical therapy prior to discharge. The degree to which changes in medical therapy occur during hospitalizations for HFrEF in North American clinical practice is unclear.

METHODS

The VICTORIA registry enrolled patients hospitalized for worsening chronic HFrEF across 51 sites in the US and Canada from February 2018-January 2019. Among patients with complete medication data and not receiving dialysis, use and dose of angiotensin-converting enzyme inhibitor (ACEI)/ angiotensin II receptor blocker (ARB), angiotensin receptor neprilysin inhibitor (ARNI), beta-blocker, mineralocorticoid receptor antagonist (MRA), and sodium glucose cotransporter-2 inhibitors (SGLT2i) were assessed at admission and discharge.

RESULTS

Among 1,695 patients, median (IQR) age was 69 (59-79) years and 33% were women. Among eligible patients, 33%, 25%, and 55% were not prescribed ACEI/ARB/ARNI, beta-blocker, and MRA at discharge, respectively; 99% were not prescribed SGLT2i. For each medication, >50% of patients remained on stable sub-target doses or no medication during hospitalization. In-hospital rates of initiation/dose increase were 20% for ACEI/ARB, 4% for ARNI, 20% for beta-blocker, 22% for MRA, and <1% for SGLT2i; corresponding rates of dose decrease/discontinuation were 11%, 2%, 9%, 5%, and <1%, respectively. Overall, 17% and 28% of eligible patients were prescribed triple therapy prior to admission and at discharge, respectively. At both admission and discharge, 1% of patients were prescribed triple therapy at target doses. Across classes of medication, multiple factors were independently associated with higher likelihood of in-hospital initiation/dosing increase (e.g., Canadian enrollment, White race, intensive care admission) and discontinuation/dosing decrease (e.g., worse renal function, intensive care admission).

CONCLUSIONS

In this contemporary North American registry of patients hospitalized for worsening chronic HFrEF, for each recommended medical therapy, the large majority of eligible patients remained on stable sub-target doses or without medication at admission and discharge. Although most patients had no alterations in medical therapy, hospitalization in Canada and multiple patient characteristics were associated with higher likelihood of favorable in-hospital medication changes.

Renal function and the effects of vericiguat in patients with worsening heart failure with reduced ejection fraction: insights from the VICTORIA (Vericiguat Global Study in Subjects with HFrEF) trial

Aims

Vericiguat reduced the primary composite outcome of cardiovascular death or heart failure (HF) hospitalization in patients with worsening HF with reduced ejection fraction (HFrEF) and a lower limit of baseline estimated glomerular filtration rate (eGFR) of 15 mL/min/1.73 m². We evaluated the relationship between the efficacy of vericiguat and baseline and subsequent changes in renal function.

Methods and results

In VICTORIA, core laboratory serum creatinine was measured at baseline (n = 4956) and weeks 16, 32, and 48. Worsening renal function (WRF), defined as an increase ≥0.3 mg/dL in creatinine from baseline to week 16, was assessed via a Cox model with respect to subsequent primary events. Mean age was 69 years, 24% were female, and mean baseline eGFR was 61 mL/min/1.73 m². During 48 weeks of treatment, the trajectories in eGFR and creatinine with vericiguat were similar to placebo (P = 0.50 and 0.18). The beneficial effects of vericiguat on the primary outcome were not influenced by baseline eGFR (interaction P = 0.48). WRF occurred in 15% of patients and was associated with worse outcomes (adjusted hazard ratio 1.28, 95% confidence interval 1.11–1.47; P < 0.001), but the beneficial effects of vericiguat on the primary outcome were similar in patients with or without WRF (interaction P = 0.76).

Conclusion

Renal function trajectories were similar between vericiguat‐ and placebo‐treated patients and the beneficial effects of vericiguat on the primary outcome were consistent across the full range of eGFR and irrespective of WRF.

Vericiguat in Patients with Heart Failure and Reduced Ejection Fraction

BACKGROUND

The effect of vericiguat, a novel oral soluble guanylate cyclase stimulator, in patients with heart failure and reduced ejection fraction who had recently been hospitalized or had received intravenous diuretic therapy is unclear.

METHODS

In this phase 3, randomized, double-blind, placebo-controlled trial, we assigned 5050 patients with chronic heart failure (New York Heart Association class II, III, or IV) and an ejection fraction of less than 45% to receive vericiguat (target dose, 10 mg once daily) or placebo, in addition to guideline-based medical therapy. The primary outcome was a composite of death from cardiovascular causes or first hospitalization for heart failure.

RESULTS

Over a median of 10.8 months, a primary-outcome event occurred in 897 of 2526 patients (35.5%) in the vericiguat group and in 972 of 2524 patients (38.5%) in the placebo group (hazard ratio, 0.90; 95% confidence interval [CI], 0.82 to 0.98; P = 0.02). A total of 691 patients (27.4%) in the vericiguat group and 747 patients (29.6%) in the placebo group were hospitalized for heart failure (hazard ratio, 0.90; 95% CI, 0.81 to 1.00). Death from cardiovascular causes occurred in 414 patients (16.4%) in the vericiguat group and in 441 patients (17.5%) in the placebo group (hazard ratio, 0.93; 95% CI, 0.81 to 1.06). The composite of death from any cause or hospitalization for heart failure occurred in 957 patients (37.9%) in the vericiguat group and in 1032 patients (40.9%) in the placebo group (hazard ratio, 0.90; 95% CI, 0.83 to 0.98; P = 0.02). Symptomatic hypotension occurred in 9.1% of the patients in the vericiguat group and in 7.9% of the patients in the placebo group (P = 0.12), and syncope occurred in 4.0% of the patients in the vericiguat group and in 3.5% of the patients in the placebo group (P = 0.30).

CONCLUSIONS

Among patients with high-risk heart failure, the incidence of death from cardiovascular causes or hospitalization for heart failure was lower among those who received vericiguat than among those who received placebo. (Funded by Merck Sharp & Dohme [a subsidiary of Merck] and Bayer; VICTORIA ClinicalTrials.gov number, NCT02861534.).

Erratum: Delayed Onset of Nonthermal Melting in Single-Crystal Silicon Pumped with Hard X Rays [Phys. Rev. Lett. 120, 265701 (2018)]

This corrects the article DOI: 10.1103/PhysRevLett.120.265701.

Blastulation of a zygote to a hatched blastocyst without any clear cell division: an observational finding in a time-lapse system after in vitro fertilization

PURPOSE

To describe an interesting not previously described morphokinetic finding.

METHODS

Retrospective case report of a couple undergoing controlled ovarian stimulation (COS) followed by in vitro fertilization and blastocyst transfer.

RESULTS

We identified a unique finding of blastulation of a fertilized human zygote after conventional in vitro fertilization. The fertilized zygote did not show any clear cytokinesis until approximately 107 h post insemination, when it started dividing into a blastocyst. By 113 h post insemination, inner cell mass and trophectoderm cells could be clearly distinguished and the blastocyst was completely hatched by 136 h post insemination.

CONCLUSION

Time-lapse systems offer more detailed observations of embryonic development. Here, we report an atypical development of an embryo that was not described previously. We hope to become an insightful discussion among peers and incentive the publication of such findings in the future.

Delayed Onset of Nonthermal Melting in Single-Crystal Silicon Pumped with Hard X Rays

In this work, we monitor the onset of nonthermal melting in single-crystal silicon by implementing an x-ray pump-x-ray probe scheme. Using the ultrashort pulses provided by the Linac Coherent Light Source (SLAC) and a custom-built split-and-delay line for hard x rays, we achieve the temporal resolution needed to detect the onset of the transition. Our data show no loss of long-range order up to 150±40  fs from photoabsorption, which we interpret as the time needed for the electronic system to equilibrate at or above the critical nonthermal melting temperature. Once such equilibration is reached, the loss of long-range atomic order proceeds inertially and is completed within 315±40  fs from photoabsorption.

Association Between Sitagliptin Use and Heart Failure Hospitalization and Related Outcomes in Type 2 Diabetes Mellitus: Secondary Analysis of a Randomized Clinical Trial

IMPORTANCE

Previous trial results have suggested that dipeptidyl peptidase 4 inhibitor (DPP4i) use might increase heart failure (HF) risk in type 2 diabetes mellitus (T2DM). The DPP4i sitagliptin has been shown to be noninferior to placebo with regard to primary and secondary composite atherosclerotic cardiovascular (CV) outcomes in the Trial Evaluating Cardiovascular Outcomes With Sitagliptin (TECOS).

OBJECTIVE

To assess the association of sitagliptin use with hospitalization for HF (hHF) and related outcomes.

DESIGN, SETTING, AND PARTICIPANTS

TECOS was a randomized, double-blind, placebo-controlled study evaluating the CV safety of sitagliptin vs placebo, each added to usual antihyperglycemic therapy and CV care among patients with T2DM and prevalent atherosclerotic vascular disease. The median follow-up was 2.9 years. The setting was 673 sites in 38 countries. Participants included 14 671 patients with T2DM and atherosclerotic vascular disease. The study dates were December 2008 through March 2015.

INTERVENTIONS

Patients were randomized to sitagliptin vs placebo added to standard care.

MAIN OUTCOMES AND MEASURES

Prespecified secondary analyses compared the effect on hHF, hHF or CV death, and hHF or all-cause death composite outcomes overall and in prespecified subgroups. Supportive analyses included total hHF events (first plus recurrent) and post-hHF death. Meta-analyses evaluated DPP4i effects on hHF and on hHF or CV death.

RESULTS

Of 14 671 patients, 7332 were randomized to sitagliptin and 7339 to placebo. Hospitalization for HF occurred in 3.1% (n = 228) and 3.1% (n = 229) of the sitagliptin and placebo groups, respectively (unadjusted hazard ratio, 1.00; 95% CI, 0.83-1.19). There was also no difference in total hHF events between the sitagliptin (n = 345) and placebo (n = 347) groups (unadjusted hazard ratio, 1.00; 95% CI, 0.80-1.25). Post-hHF all-cause death was similar in the sitagliptin and placebo groups (29.8% vs 28.8%, respectively), as was CV death (22.4% vs 23.1%, respectively). No heterogeneity for the effect of sitagliptin on hHF was observed in subgroup analyses across 21 factors (P > .10 for all interactions). Meta-analysis of the hHF results from the 3 reported DPP4i CV outcomes trials revealed moderate heterogeneity (I2 = 44.9, P = .16).

CONCLUSIONS AND RELEVANCE

Sitagliptin use does not affect the risk for hHF in T2DM, both overall and among high-risk patient subgroups.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00790205.

Reassessing Phase II Heart Failure Clinical Trials: Consensus Recommendations

The increasing burden and the continued suboptimal outcomes for patients with heart failure underlines the importance of continued research to develop novel therapeutics for this disorder. This can only be accomplished with successful translation of basic science discoveries into direct human application through effective clinical trial design and execution that results in a substantially improved clinical course and outcomes. In this respect, phase II clinical trials play a pivotal role in determining which of the multitude of potential basic science discoveries should move to the large and expansive registration trials in humans. A critical examination of the phase II trials in heart failure reveals multiple shortcomings in their concept, design, execution, and interpretation. To further a dialogue on the challenges and potential for improvement and the role of phase II trials in patients with heart failure, the Food and Drug Administration facilitated a meeting on October 17, 2016, represented by clinicians, researchers, industry members, and regulators. This document summarizes the discussion from this meeting and provides key recommendations for future directions.

Effect of Sitagliptin on Cardiovascular Outcomes in Type 2 Diabetes

BACKGROUND

Data are lacking on the long-term effect on cardiovascular events of adding sitagliptin, a dipeptidyl peptidase 4 inhibitor, to usual care in patients with type 2 diabetes and cardiovascular disease.

METHODS

In this randomized, double-blind study, we assigned 14,671 patients to add either sitagliptin or placebo to their existing therapy. Open-label use of antihyperglycemic therapy was encouraged as required, aimed at reaching individually appropriate glycemic targets in all patients. To determine whether sitagliptin was noninferior to placebo, we used a relative risk of 1.3 as the marginal upper boundary. The primary cardiovascular outcome was a composite of cardiovascular death, nonfatal myocardial infarction, nonfatal stroke, or hospitalization for unstable angina.

RESULTS

During a median follow-up of 3.0 years, there was a small difference in glycated hemoglobin levels (least-squares mean difference for sitagliptin vs. placebo, -0.29 percentage points; 95% confidence interval [CI], -0.32 to -0.27). Overall, the primary outcome occurred in 839 patients in the sitagliptin group (11.4%; 4.06 per 100 person-years) and 851 patients in the placebo group (11.6%; 4.17 per 100 person-years). Sitagliptin was noninferior to placebo for the primary composite cardiovascular outcome (hazard ratio, 0.98; 95% CI, 0.88 to 1.09; P<0.001). Rates of hospitalization for heart failure did not differ between the two groups (hazard ratio, 1.00; 95% CI, 0.83 to 1.20; P=0.98). There were no significant between-group differences in rates of acute pancreatitis (P=0.07) or pancreatic cancer (P=0.32).

CONCLUSIONS

Among patients with type 2 diabetes and established cardiovascular disease, adding sitagliptin to usual care did not appear to increase the risk of major adverse cardiovascular events, hospitalization for heart failure, or other adverse events. (Funded by Merck Sharp & Dohme; TECOS ClinicalTrials.gov number, NCT00790205.).

Clinical outcome endpoints in heart failure trials: a European Society of Cardiology Heart Failure Association consensus document

Endpoint selection is a critically important step in clinical trial design. It poses major challenges for investigators, regulators, and study sponsors, and it also has important clinical and practical implications for physicians and patients. Clinical outcomes of interest in heart failure trials include all-cause mortality, cause-specific mortality, relevant non-fatal morbidity (e.g., all-cause and cause-specific hospitalization), composites capturing both morbidity and mortality, safety, symptoms, functional capacity, and patient-reported outcomes. Each of these endpoints has strengths and weaknesses that create controversies regarding which is most appropriate in terms of clinical importance, sensitivity, reliability, and consistency. Not surprisingly, a lack of consensus exists within the scientific community regarding the optimal endpoint(s) for both acute and chronic heart failure trials. In an effort to address these issues, the Heart Failure Association of the European Society of Cardiology (HFA-ESC) convened a group of expert heart failure clinical investigators, biostatisticians, regulators, and pharmaceutical industry scientists (Nice, France, 12-13 February 2012) to evaluate the challenges of defining heart failure endpoints in clinical trials and to develop a consensus framework. This report summarizes the group's recommendations for achieving common views on heart failure endpoints in clinical trials.

Effect of adenosine-regulating agent acadesine on morbidity and mortality associated with coronary artery bypass grafting: the RED-CABG randomized controlled trial

CONTEXT

Ischemia/reperfusion injury remains an important cause of morbidity and mortality after coronary artery bypass graft (CABG) surgery. In a meta-analysis of randomized controlled trials, perioperative and postoperative infusion of acadesine, a first-in-class adenosine-regulating agent, was associated with a reduction in early cardiac death, myocardial infarction, and combined adverse cardiac outcomes in participants undergoing on-pump CABG surgery.

OBJECTIVE

To assess the efficacy and safety of acadesine administered in the perioperative period in reducing all-cause mortality, nonfatal stroke, and severe left ventricular dysfunction (SLVD) through 28 days.

DESIGN, SETTING, AND PARTICIPANTS

The Reduction in Cardiovascular Events by Acadesine in Patients Undergoing CABG (RED-CABG) trial, a randomized, double-blind, placebo-controlled, parallel-group evaluation of intermediate- to high-risk patients (median age, 66 years) undergoing nonemergency, on-pump CABG surgery at 300 sites in 7 countries. Enrollment occurred from May 6, 2009, to July 30, 2010.

INTERVENTIONS

Eligible participants were randomized 1:1 to receive acadesine (0.1 mg/kg per minute for 7 hours) or placebo (both also added to cardioplegic solutions) beginning just before anesthesia induction.

MAIN OUTCOME MEASURE

Composite of all-cause mortality, nonfatal stroke, or need for mechanical support for SLVD during and following CABG surgery through postoperative day 28.

RESULTS

Because results of a prespecified futility analysis indicated a very low likelihood of a statistically significant efficacious outcome, the trial was stopped after 3080 of the originally projected 7500 study participants were randomized. The primary outcome occurred in 75 of 1493 participants (5.0%) in the placebo group and 76 of 1493 (5.1%) in the acadesine group (odds ratio, 1.01 [95% CI, 0.73-1.41]). There were no differences in key secondary end points measured.

CONCLUSION

In this population of intermediate- to high-risk patients undergoing CABG surgery, acadesine did not reduce the composite of all-cause mortality, nonfatal stroke, or SLVD.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00872001.

Effects of sources of variability on sample sizes required for RCTs, applied to trials of lipid-altering therapies on carotid artery intima-media thickness

Objective Studies measuring progression of carotid artery intima-media thickness (cIMT) have been used to estimate the effect of lipid-modifying therapies cardiovascular event risk. The likelihood that future cIMT clinical trials will detect a true treatment effect is estimated by leveraging results from prior studies. The present analyses assess the impact of between- and within-study variability based on currently published data from prior clinical studies on the likelihood that ongoing or future cIMT trials will detect the true treatment effect of lipid-modifying therapies.

Methods Published data from six contemporary cIMT studies (ASAP, ARBITER 2, RADIANCE 1, RADIANCE 2, ENHANCE, and METEOR) including data from a total of 3563 patients were examined. Bayesian and frequentist methods were used to assess the impact of between study variability on the likelihood of detecting true treatment effects on 1-year cIMT progression/regression and to provide a sample size estimate that would specifically compensate for the effect of between-study variability.

Results In addition to the well-described within-study variability, there is considerable between-study variability associated with the measurement of annualized change in cIMT. Accounting for the additional between-study variability decreases the power for existing study designs. In order to account for the added between-study variability, it is likely that future cIMT studies would require a large increase in sample size in order to provide substantial probability (≥90%) to have 90% power of detecting a true treatment effect.

Limitation Analyses are based on study level data. Future meta-analyses incorporating patient-level data would be useful for confirmation.

Conclusion Due to substantial within- and between-study variability in the measure of 1-year change of cIMT, as well as uncertainty about progression rates in contemporary populations, future study designs evaluating the effect of new lipid-modifying therapies on atherosclerotic disease progression are likely to be challenged by large sample sizes in order to demonstrate a true treatment effect.

Meta-analysis of angiographic versus intravascular ultrasound parameters of drug-eluting stent efficacy (from TAXUS IV, V, and VI)

Both quantitative coronary angiography (QCA) and intravascular ultrasound (IVUS) are currently used to assess in-stent restenosis. This study aimed to use standardized imaging and clinical follow-up to compare QCA parameters with several IVUS parameters to evaluate their strengths and weaknesses for detecting in-stent restenosis in a drug-eluting stent population. A subset of patients from the TAXUS IV, V, and VI studies was evaluated. The subset, which included 216 TAXUS-treated patients and 191 bare-metal stent-treated patients, had complete IVUS and QCA performed at baseline and follow-up. As expected, all QCA and IVUS parameters were consistent with less intimal hyperplasia in TAXUS patients than controls. The overall incidence of QCA binary restenosis was 14.0%, which was 9.3% in TAXUS-treated patients and 19% in bare-metal stent-treated patients (p = 0.0008). Regression analysis showed that QCA late lumen loss and percentage of diameter stenosis correlated only moderately with the various IVUS measures of neointimal hyperplasia for the combined group of patients (TAXUS + bare-metal stent), as well as for the TAXUS-treated and bare-metal stent-treated patients separately. However, in general, correlations within the control (bare-metal stent) group tended to be stronger than within the TAXUS group. The strongest correlation was between QCA percentage of diameter stenosis and IVUS percentage of intimal hyperplasia in the overall group and the control group. The strongest IVUS predictor of QCA binary restenosis at 9 months was maximum percentage of intimal hyperplasia, with an overall C = 0.91 and p <0.001. In conclusion, the QCA and IVUS parameters used to evaluate drug-eluting stent efficacy showed a moderate correlation with IVUS percentage of intimal hyperplasia, reliably predicting QCA binary in-stent restenosis.

Offsetting Impact of Thrombosis and Restenosis on the Occurrence of Death and Myocardial Infarction After Paclitaxel-Eluting and Bare Metal Stent Implantation

Background— Drug-eluting stents compared with bare metal stents (BMS) may increase late stent thrombosis (ST), although an accompanying increase in the rates of death and myocardial infarction (MI) has not been observed. We hypothesized that the prevention of restenosis-related adverse events by drug-eluting stents might offset some or all of the excess risk from ST.

Methods and Results— We analyzed a pooled patient-level database from 4 prospective, double-blind trials in which 3445 patients were randomized to paclitaxel-eluting stents or BMS. The occurrence of death or MI within 7 days of ST or target lesion revascularization was assessed. With a median follow-up of 3.2 years, ST occurred in 34 patients (1.0%), 31 (91.1%) of whom sustained death or MI within 7 days. Target lesion revascularization was performed in 425 patients (12.3%), 15 (3.5%) of whom died or had MI within 7 days. ST occurred in 14 BMS and 20 paclitaxel-eluting stent patients, resulting in 12 and 19 deaths or MIs within 7 days, respectively. Target lesion revascularization was performed in 290 BMS and 135 paclitaxel-eluting stent patients, resulting in 11 and 4 deaths or MI events within 7 days, respectively. In total, 23 patients in both the BMS and paclitaxel-eluting stents groups died or had an MI event within 7 days of either ST or target lesion revascularization.

Conclusions— ST, although infrequent, results in a high incident rate of death and MI, whereas the more frequent occurrence of target lesion revascularization is associated with a finite but lower rate of death and MI. The marked reduction in restenosis with drug-eluting stents compared with BMS may counterbalance the potential excess risk from late ST with drug-eluting stents.

Effect of the polymer-based, paclitaxel-eluting TAXUS Express stent on vascular tissue responses: a volumetric intravascular ultrasound integrated analysis from the TAXUS IV, V, and VI trials

AIMS

The TAXUS Express stent has been shown to reduce angiographic restenosis, repeat revascularizations, and neointimal hyperplasia when compared with bare metal stent (BMS) control (TAXUS IV, V, and VI) in individual TAXUS trials. Since intravascular ultrasound (IVUS) methodology and core laboratory were consistent among all three TAXUS trials, an integrated analysis of 956 patients across all IVUS cohorts can be performed providing superior power.

METHODS AND RESULTS

In the TAXUS randomized trials, patients received an Express BMS or paclitaxel-eluting TAXUS Express stent. Volumetric analysis was performed on a selected subgroup at implantation and 9 months. Compared with BMS control, TAXUS increased 9-month lumen volumes (144 +/- 79 vs. 179 +/- 95 mm(3); P < 0.0001) due to reduced neointimal volume (66 +/- 49 vs. 27 +/- 30 mm(3); P < 0.0001). This corresponded to a 61% decrease in net lumen volume obstruction (31 +/- 15 vs. 12 +/- 12 mm(3); P < 0.0001). Lumen loss was similar between groups for the proximal 5 mm outside the stent but was reduced in TAXUS at the distal edge (P = 0.0056). Neointimal hyperplasia was significantly reduced in the double-strut region of overlapping TAXUS vs. BMS control and in high-risk patients with diabetes, long lesions, multiple stents, and multiple overlapping stents. Late-acquired incomplete stent apposition (ISA) was more common with moderate-release TAXUS stents. Importantly, there were no major adverse cardiac events or stent thromboses in any late-acquired ISA patient through 2 years. Univariate and multivariable analyses revealed that longer lesion length and previous myocardial infarction are risk factors for late-acquired ISA.

CONCLUSION

Integrated analysis of the TAXUS trials shows that the paclitaxel-eluting TAXUS Express stent effectively inhibits in-stent neointimal proliferation, even in high-risk and overlapping stent patients.

Polymer-Based, Paclitaxel-Eluting TAXUS Liberté Stent in De Novo Lesions

OBJECTIVES

The goal of this research was to assess non-inferiority of the next-generation TAXUS Liberté stent (Boston Scientific Corp., Natick, Massachusetts) versus the TAXUS Express stent (Boston Scientific Corp.).

BACKGROUND

The introduction of drug-eluting stents (DES) has shifted clinical practice towards more complex lesion subsets, prompting the need for more deliverable DES. TAXUS Liberté was designed to combine the established polymer-based, paclitaxel-elution TAXUS technology with the more advanced Liberté stent platform.

METHODS

The TAXUS ATLAS study is a global, prospective, single-arm trial evaluating outcomes in de novo coronary lesions visually estimated to be 10 to 28 mm in length in vessels 2.5 to 4.0 mm in diameter. The control group is an entry-criteria-matched population of TAXUS Express patients from the TAXUS IV and V trials. The primary end point is non-inferiority of TAXUS Liberté versus TAXUS Express for 9-month target vessel revascularization.

RESULTS

Despite similar inclusion criteria, quantitative coronary angiography-determined baseline lesion characteristics were significantly more complex for TAXUS Liberté than TAXUS Express. The primary non-inferiority end point was met with the 1-sided 95% confidence bound of 2.98% less than the pre-specified non-inferiority margin of 3% (p = 0.0487).

CONCLUSIONS

Despite the treatment of more complex lesions with TAXUS Liberté, the primary end point was met, demonstrating that TAXUS Liberté is non-inferior to TAXUS Express. The successful transfer of the proven TAXUS technology to the more advanced TAXUS Liberté platform was demonstrated. (TAXUS ATLAS: TAXUS Liberté-SR Stent for the Treatment of De Novo Coronary Artery Lesions; http://www.clinicaltrials.gov/ct/show/NCT00371709?order=1; NCT00371709).

Two-year serial coronary angiographic and intravascular ultrasound analysis of in-stent angiographic late lumen loss and ultrasonic neointimal volume from the TAXUS II trial

Late loss has been used as a reliable surrogate end point for evaluation and differentiation of short-term performance of drug-eluting stents. This study investigated the consistency between angiographic and intravascular ultrasound (IVUS) outcomes of late lumen loss (late loss) and neointimal growth to measure restenotic plaque load in TAXUS and bare metal stents. The randomized TAXUS II trial evaluates the polymer-based paclitaxel-eluting TAXUS stent in slow- and moderate-release formulations. Serial angiographic and IVUS analyses were available in 155 event-free patients (bare metal stent, 74; TAXUS stent, 81) after the procedure, at 6 months, and at 2 years. For this subanalysis, quantitative coronary angiographic (QCA) and IVUS measurements were used to derive late loss and neointimal volume. From after the procedure to 6 months, quantitative coronary angiography and IVUS showed matching results for the 2 groups with significant decreases in late loss and neointimal volume in the TAXUS versus the control group. From 6 months to 2 years, QCA and IVUS measurements also showed results similar to those in the control group, demonstrating neointimal compaction over time. However, in the TAXUS group, QCA late loss showed a nonsignificant decrease from 6 months to 2 years, whereas IVUS neointimal volume increased. In conclusion, although QCA and IVUS results were similar over the first 6 months, long-term assessment of changes in restenotic plaque load showed discrepant findings for the TAXUS. These findings suggest the need for critical reevaluation of current end points and the use of more precise techniques to detect lumen and stent boundaries.

Incidence, Timing, and Correlates of Stent Thrombosis With the Polymeric Paclitaxel Drug-Eluting Stent

OBJECTIVES

This study sought to study stent thrombosis with the paclitaxel-eluting Taxus stent.

BACKGROUND

The incidence and timing of stent thrombosis after drug-eluting stent placement compared with bare-metal stent implantation remain unsettled, with consequent uncertainty about risk stratification and long-term recommendations for antiplatelet medications.

METHODS

This study used a patient-based meta-analysis using the 4 principal TAXUS randomized trials (3,445 patients) with a follow-up duration of > or =1 year.

RESULTS

Cumulative stent thrombosis occurred in 1.28% +/- 0.31% in the Taxus group and 0.76% +/- 0.23% in the bare-metal stent group at 3 years (hazard ratio 1.51 [95% confidence interval 0.73 to 3.14], p = 0.26). Hazard ratios (per 100 patients per 6 months) were similar between the Taxus stent group (0.59 [95% confidence interval 0.22 to 0.95]) and the bare-metal stent group (0.64 [95% confidence interval 0.26 to 1.02]) through 6 months during the prescribed clopidogrel period. However, from 6 months to 3 years there were more stent thromboses in the Taxus group (hazard ratio 0.19 [95% confidence interval 0.06 to 0.32] vs. 0.02 [95% confidence interval 0.00 to 0.07], p = 0.049). Of 8 patients with Taxus-related thrombosis after 6 months, 0 were taking clopidogrel and 2 were not taking aspirin consistently. No Taxus-related stent thrombosis occurred after 2 years (922 patients thus far followed up for 3 years). Independent correlates of stent thrombosis were nonuse of clopidogrel, male gender, smoking, and possibly use of multiple nonoverlapping stents.

CONCLUSIONS

Approximately 0.8% of Taxus patients have stent thrombosis in the first 6 months after stent implantation, similar to bare-metal stents. However, a modest increase in risk is present with Taxus stents beyond 6 months, possibly because of inadequate antiplatelet drug therapy.

An Overview of the TAXUS�Express�, Paclitaxel-Eluting Stent Clinical Trial Program

Restenosis remains a problem following percutaneous coronary intervention in patients with coronary artery disease. Drug-eluting stents (DES), which combine mechanical and pharmacologic properties, have been shown to prevent or reduce neointimal growth after deployment. This review describes the TAXUS paclitaxel-eluting stent clinical trial expansion program (TAXUS Express, Boston Scientific, Natick, MA). This program comprises the largest data set of randomized controlled trials (RCTs) of DES to date, with over 6,200 patients enrolled since 2000. The program includes treatment of de novo lesions, as well as higher-risk lesion and patient populations. In this review, we discuss the results from the TAXUS family of randomized clinical trials, and compare the findings with data from TAXUS registries. The data from the randomized clinical trials suggest that the paclitaxel-eluting stent provides consistent and durable benefits across multiple lesion and patient types. Evidence from peri-and post-approval registries, where patient populations are more heterogeneous than those eligible and included in the RCTs, corroborate these findings, with overall low rates of cardiac events, including reinterventions.

The SYNergy between percutaneous coronary intervention with TAXus and cardiac surgery (SYNTAX) study: design, rationale, and run-in phase

BACKGROUND

Changes in the treatment of coronary artery disease both surgically and percutaneously have rendered the major randomized trials historical. Furthermore, the restrictive criteria of previous trials excluded most patients treated in daily practice. Although coronary surgery is still considered the current, evidence-based, gold-standard treatment of left main (LM) and 3-vessel coronary disease, the added benefit of drug-eluting stents has further expanded the use of percutaneous coronary intervention (PCI) beyond less complex populations in daily practice.

STUDY DESIGN

The 1500-patient, prospective, multicenter, multinational (European and North American), randomized SYNTAX study with nested registries will enroll "all-comers." Consecutive patients with de novo 3-vessel disease (3VD) and/or LM disease will be screened for eligibility by the Heart Team (composed of an interventionalist, a cardiac surgeon, and the study coordinator) at each site and then allocated to either (1) the randomized cohort, if comparable revascularization can be achieved by either PCI or coronary artery bypass surgery (CABG), or (2) to one of the nested registries for CABG-ineligible patients (PCI registry) or for PCI-ineligible patients (CABG registry). Randomized patients will be stratified based on LM disease and diabetes by site. The primary end point for the randomized comparison is noninferiority of major adverse cardiac and cerebral events between the 2 groups at 1 year. To adequately project the expected enrollment rate per site, a run-in phase was mandated for each site interested in participating in the trial. Both cardiothoracic and interventional cardiology departments within the same institution were asked to complete a questionnaire regarding their frequency of treatment of LM and 3VD over a retrospective 3-month period.

IMPLICATIONS

By replacing most traditional inclusion and exclusion criteria with the real-world decision between the cardiothoracic surgeon and the interventionalist, this study will define the roles of CABG and PCI using drug-eluting stents in the contemporary management of LM and 3VD. Results of the run-in phase were used by the steering committee to determine eligibility and to project enrollment for each site.

Integrated analysis of medically treated diabetic patients in the TAXUS(R) program: benefits across stent platforms, paclitaxel release formulations, and diabetic treatments

OBJECTIVES

The TAXUS(R) database was used to perform an integrated analysis across several large phase II and III trials to assess outcomes of polymer-based paclitaxel-eluting TAXUS stents in diabetic patients.

BACKGROUND

While drug-eluting stents have reduced the risk for restenosis, diabetic patients remain at higher risk.

METHODS

This post hoc analysis of clinical and angiographic outcomes combined individual patient data from four randomized, multicentre, controlled clinical trials (TAXUS II, IV, V, and VI) representing outcomes across two paclitaxel release formulations and stent platforms.

RESULTS

Breslow-Day analysis indicated homogeneous odds ratios across dose formulations and stent platforms, thus clinical data (9 months) were pooled from 3445 patients, including 814 diabetic patients. The randomized quantitative coronary angiography subset (n=2863) included 469 diabetic patients requiring oral medications only and 216 insulin-treated. Among patients receiving bare metal stents (BMS), those with diabetes had worse clinical and angiographic outcomes than non-diabetic patients. Target lesion revascularization rates were decreased in TAXUS patients relative to BMS controls by 59% (p=0.0001) among diabetic patients requiring oral medications, by 66% (p=0.006) among insulin-treated. Insulin-treated patients showed a significant TAXUS benefit for in-stent and in-segment percent diameter stenosis (p=0.0001, p=0.001, respectively) and late loss (p=0.001); a similar TAXUS benefit was seen in diabetic patients treated with oral medications (p<0.0001). Binary restenosis in-segment was significantly decreased 65% in both diabetic subsets (p=0.0001).

CONCLUSION

This post hoc analysis of data from four combined randomized TAXUS trials suggests the TAXUS benefit observed in non-diabetic patients is carried over into the high-risk diabetic population.

Peristent remodeling and neointimal suppression 2 years after polymer-based, paclitaxel-eluting stent implantation: insights from serial intravascular ultrasound analysis in the TAXUS II study

BACKGROUND

The purpose of this study was to evaluate long-term vascular responses as long as 2 years after implantation of polymer-based, paclitaxel-eluting stents in contrast to uncoated stents.

METHODS AND RESULTS

TAXUS II is a randomized, double-blind trial comparing slow-release (SR) and moderate-release (MR) TAXUS stents with bare-metal control stents (BMSs). One hundred sixty-one event-free patients (SR, 43; MR, 41; and BMS, 77) underwent serial intravascular ultrasound (IVUS) analysis after the procedure and at 6 months and 2 years. At 2 years, neointimal responses continued to be significantly suppressed in the SR and MR groups when compared with the BMS group (BMS, 1.49+/-1.12 mm2; SR, 0.94+/-0.76 mm2 [P=0.004]; and MR, 1.06+/-0.90 mm2 [P=0.02]). Between 6 months and 2 years, the BMS group showed compaction of the neointima (Delta, -0.22+/-1.05 mm2 [P=0.08]). In contrast, both the SR and MR groups exhibited an increase (Delta SR, 0.30+/-0.76 mm2 (P=0.01); MR, 0.41+/-0.94 mm2 [P=0.009]). Between 6 months and 2 years, the initial increase in plaque outside the stent regressed in the BMS and SR groups to levels comparable to those after the procedure, whereas expansive remodeling partially regressed in the MR group (Delta between after the procedure and 2 years BMS, -0.34+/-1.28 mm2 [P=0.05]; SR, -0.02+/-1.40 mm2 [P=0.93]; MR, 0.32+/-1.56 mm2 [P=0.27]).

CONCLUSIONS

The 2-year follow-up demonstrates that neointimal suppression was dose independent and that this effect was still sustained at 2 years. However, the increase in area outside the stent seen at 6 months regressed to different extents in a dose-dependent manner at 2 years.

Clinical Efficacy of Polymer-Based Paclitaxel-Eluting Stents in the Treatment of Complex, Long Coronary Artery Lesions From a Multicenter, Randomized Trial

Background— Intracoronary polymer-based stent delivery of paclitaxel has been shown to be effective in reducing restenosis in simple coronary lesions, but the evidence base for contemporary use in longer, more complex coronary stenoses is lacking.

Methods and Results— TAXUS VI is a prospective, multicenter, double-blind, randomized trial assessing clinical and angiographic outcomes of the TAXUS Moderate Release paclitaxel-eluting stent in the treatment of long, complex coronary artery lesions. Four hundred forty-eight patients at 44 sites were randomized (1:1) between a drug-eluting TAXUS Express 2 and an uncoated Express 2 control stent. Per protocol, the 9-month follow-up included an angiographic reevaluation in all patients. The primary end point was the rate of target-vessel revascularization 9 months after the study procedure; secondary end points included the rate of target-lesion revascularization and binary restenosis at follow-up. Mean lesion length in the study was 20.6 mm, with a mean stent-covered length of 33.4 mm. Of all lesions, 55.6% were classified as complex lesions (type C of the AHA/ACC classification). At 9 months, target-vessel revascularization was 9.1% in the TAXUS group and 19.4% in the control group ( P =0.0027; relative reduction, 53%). Target-lesion revascularization was reduced from 18.9% to 6.8%, respectively ( P =0.0001). The incidence of major adverse cardiac events was similar in the 2 groups, 16.4% and 22.5% in TAXUS and control, respectively ( P =0.12), including comparable rates for acute myocardial infarction. Binary restenosis in the stented area was reduced from 32.9% in the control group to 9.1% in the TAXUS patients ( P <0.0001).

Conclusions— The finding that the TAXUS Moderate Release stent system is safe and effective in the treatment of long, complex coronary artery lesions provides the evidence base for the more widespread use of drug-eluting stents in contemporary clinical practice.

Comparison of a polymer-based paclitaxel-eluting stent with a bare metal stent in patients with complex coronary artery disease: a randomized controlled trial

CONTEXT

Compared with bare metal stents, drug-eluting stents reduce restenosis in noncomplex lesions. The utility of drug-eluting stents has not been evaluated in more difficult stenoses.

OBJECTIVE

To investigate the safety and efficacy of the polymer-based, slow-release paclitaxel-eluting stent in a patient population with more complex lesions than previously studied.

DESIGN, SETTING, AND PATIENTS

Prospective, placebo-controlled, double-blind, multicenter randomized trial conducted from February 2003 to March 2004 at 66 academic and community-based institutions with 1156 patients who underwent stent implantation in a single coronary artery stenosis (vessel diameter, 2.25-4.0 mm; lesion length, 10-46 mm), including 664 patients (57.4%) with complex or previously unstudied lesions (requiring 2.25-mm, 4.0-mm, and/or multiple stents) and 9-month clinical and angiographic follow-up.

INTERVENTIONS

Patients were randomly assigned to receive 1 or more bare metal stents (n = 579) or identical-appearing paclitaxel-eluting stents (n = 577).

MAIN OUTCOME MEASURE

Ischemia-driven target vessel revascularization at 9 months.

RESULTS

Baseline characteristics were well matched. Diabetes was present in 31% of patients. The mean (SD) reference vessel diameter was 2.69 (0.57) mm, the reference lesion length was 17.2 (9.2) mm, and 78% of lesions were type B2/C. A mean (SD) of 1.38 (0.58) stents (total mean [SD] length, 28.4 [13.1] mm) were implanted per lesion; 33% of lesions required multiple stents. Stents that were 2.25 mm and 4.0 mm in diameter were used in 18% and 17% of lesions, respectively. Compared with bare metal stents, paclitaxel-eluting stents reduced the 9-month rate of target lesion revascularization from 15.7% to 8.6% (P<.001) and target vessel revascularization from 17.3% to 12.1% (P = .02). Similar rates were observed for cardiac death or myocardial infarction (5.5% for bare metal stent group vs 5.7% for paclitaxel-eluting stent group) and stent thrombosis (0.7% in both groups). Angiographic restenosis was reduced from 33.9% to 18.9% in the entire study cohort (P<.001), including among patients receiving 2.25-mm stents (49.4% vs 31.2%; P = .01), 4.0-mm stents (14.4% vs 3.5%; P = .02), and multiple stents (57.8% vs 27.2%; P<.001).

CONCLUSION

Compared with a bare metal stent, implantation of the paclitaxel-eluting stent in a patient population with complex lesions effectively reduces clinical and angiographic restenosis.

Enhanced T-helper-1 lymphocyte activation patterns in acute coronary syndromes

OBJECTIVES

We sought to determine whether different stages of coronary artery disease (CAD) are associated with distinct differentiation patterns of activated T cells.

BACKGROUND

Atherosclerosis is an inflammatory disease. However, little is known about specific inflammatory cell activation in atherosclerosis, for example, the T-helper (Th)1/Th2-balance.

METHODS

We studied 18 patients with stable angina (SA), 28 patients with acute coronary syndrome (ACS) (16 with unstable angina pectoris and 12 with ST-segment elevation myocardial infarction), 19 patients with unheralded myocardial infarction (UH), and 16 control patients. Cytokine patterns and transcription factor signaling pathways of circulating T cells were characterized using reverse transcription polymerase chain reaction and flow cytometry.

RESULTS

Although interferon (IFN)-gamma(+)/CD3(+) T cells were approximately 2-fold greater in patients with SA or UH than in control subjects, there was a massive expansion of Th1 cells in patients with ACS (p < 0.001). This increase was paralleled by significantly increased mRNA transcript levels for signal-transducer-and-activator-4 (ACS 1.17 +/- 0.14 relative units [RU]; control patients 0.44 +/- 0.09 RU; SA 0.67 +/- 0.12 RU; UH 0.61 +/- 0.17 RU), interleukin-2 (ACS 1.55 +/- 0.51 RU; control patients 0.21 +/- 0.09 RU; SA 0.54 +/- 0.18 RU; UH 0.45 +/- 0.16 RU), and IFN-gamma in ACS (1.27 +/- 0.39 RU; control patients 0.35 +/- 0.09 RU; SA 0.58 +/- 0.11 RU; UH 0.53 +/- 0.24 RU; p < 0.002). Th2 and Th0 cells were not different across patient subsets. The burden of CAD was identical between SA (1.4 +/- 0.2 diseased vessels, 68 +/- 13% diameter stenosis) and ACS (1.4 +/- 0.2 diseased vessels, 64 +/- 17% diameter stenosis) but significantly greater in patients with UH (2.5 +/- 0.5 diseased vessels, 95 +/- 7% diameter stenosis; p < 0.05).

CONCLUSIONS

Patients with UH have a greater burden of obstructive CAD than SA but no greater T-cell activation. Patients with ACS have the same extent of CAD than SA but significantly greater activation of Th1 cells that may contribute to the increasing instability. Differences in circulating Th1 cells might indicate different pathogenic components, leading to ACS and UH.

Peripheral Expansion of Circulating T-Helper 1 Cells Predicts Coronary Endothelial Dysfunction After Cardiac Transplantation

OBJECTIVE

We sought to assess the importance of Th1 cells for the development of cardiac allograft vasculopathy.

BACKGROUND

Despite improvements in immunosuppressive regimens, chronic rejection still represents one of the leading causes of death beyond the first year after heart transplantation. Chronic rejection is characterized by the development of transplant vasculopathy. The exact mechanisms initiating and promoting this form of arteriosclerosis in the human setting remain unclear.

METHODS

In order to assess the role of T lymphocytes we characterized differentiated T-cell subsets in 32 transplant recipients early after transplantation using RT-PCR, flow cytometry and immunhistochemistry and matched these findings with endothelial function testing as an early clinical indicator of transplant vasculopathy.

RESULTS

Allograft endothelial dysfunction (ED) was defined as a compromised coronary flow reserve to acetylcholine (CFVR<2 in 8 of 32 transplant recipients). In these patients, mRNA transcript levels for the T-helper (Th)1 signature cytokines interferon (INF)-gamma (p<0.0001) and interleukin (IL)-2 (p<0.005) and STAT4 (Th1 transcription factor, p<0,05) were significantly higher than in the remaining 24 patients with normal endothelial function. This correlated with a significant increase in circulating CD3(+)/IFN-gamma(+)-T-cells (28.6 +/- 4.4% vs 8.7 +/- 5.6%; p<0.0001). In contrast, transcript levels for the Th2 signature cytokines (IL-4, IL-10) and STAT6 (Th2 transcription factor) did not differ significantly between the two groups.

CONCLUSIONS

Peripheral expansion of circulating Th1 but not Th2 cells predicts coronary ED after cardiac transplantation. Therefore, quantification of circulating T cells might be a diagnostic tool to predict development of ED in patients after heart transplantation.

Expansion of circulating Toll-like receptor 4-positive monocytes in patients with acute coronary syndrome

BACKGROUND

Atherosclerosis is an inflammatory disease in which monocytes and macrophages have been suggested to play an essential role. The underlying signaling mechanisms are unknown thus far. We hypothesized that the human isoform of Toll-like receptor (hTLR)-4 is involved in monocyte activation of patients with accelerated forms of atherosclerosis.

METHODS AND RESULTS

Expression of hTLR4 on circulating monocytes from 30 controls, 20 patients with stable angina (SA), 40 patients with unstable angina (UA), and 28 patients with acute myocardial infarction (AMI) was compared with the use of flow-cytometry and reverse transcription-polymerase chain reaction. Regulation of interleukin (IL)-12 and B7-1 as downstream events of TLR4 activation was analyzed after lipopolysaccharide stimulation of monocytes. TLR4-transfected Chinese hamster ovary (CHO) cells were used to identify potential hTLR4 ligands in the serum of patients with UA or AMI. Circulating hTLR4+/CD14+ monocytes were approximately 2.5-fold increased above controls and patients with SA in the UA and AMI groups (P<0.0001). This was paralleled by enhanced transcript levels of TLR4 and Myd88 in patients with UA and AMI (P<0.0001) and increased expression of IL-12 (UA 35.5+/-7.8, AMI 31.8+/-7.7 versus SA 2.2+/-0.5, controls 2.1+/-0.3 pg/mL; P<0.0002) and B7-1 (UA 27.3+/-14.4, AMI 22.6+/-11.1 versus SA 3.4+/-2.5, controls 2.4+/-2.3%; P<0.0001). Compared with serum from patients with UA and AMI, challenging TLR4-transfected CHO cells with serum from SA patients yielded only a weak response (P<0.0001). Coincubation with anti-heat shock protein 60 inhibited CHO cell activation.

CONCLUSIONS

UA and AMI are associated with enhanced expression and signaling events downstream of hTLR4 in circulating monocytes. These observations suggest hTLR4 activation as a signaling mechanism in immune-mediated progression of atherosclerosis.

Polymer-based paclitaxel-eluting stents reduce in-stent neointimal tissue proliferation

OBJECTIVES

The aim of this study was to use serial volumetric intravascular ultrasound (IVUS) to evaluate the effects of polymer-based, paclitaxel-eluting stents on in-stent neointima formation and late incomplete stent apposition.

BACKGROUND

The TAXUS-IV trial demonstrated that the slow-release, polymer-based, paclitaxel-eluting stent reduces angiographic restenosis and the need for repeat revascularization procedures. Serial IVUS studies reveal details of the pattern of vascular responses provoked by stent implantation that provide insight into device safety and efficacy.

METHODS

In the TAXUS-IV trial, patients were randomized to the slow-release, polymer-based, paclitaxel-eluting TAXUS stent or a bare-metal EXPRESS stent (Boston Scientific Corp., Natick, Massachusetts). As part of a formal substudy, complete volumetric IVUS data were available in 170 patients, including 88 TAXUS patients and 82 controls, at implantation and at nine-month follow-up.

RESULTS

No baseline differences were present in the clinical characteristics or IVUS parameters between the control and TAXUS groups. At nine-month follow-up, IVUS lumen volumes were larger in the TAXUS group (123 +/- 43 mm(3) vs. 104 +/- 44 mm(3), p = 0.005), due to a reduction in neointimal volume (18 +/- 18 mm(3) vs. 41 +/- 23 mm(3), p < 0.001). Millimeter-by-millimeter analysis within the stent demonstrated uniform suppression of neointimal growth along the entire stent length. Late lumen loss was similar at the proximal edge of the stent between the two groups, and reduced with the TAXUS stent at the distal edge (p = 0.004). Incomplete stent apposition at nine months was observed in only 3.0% of control and 4.0% of TAXUS stents (p = 0.12).

CONCLUSIONS

Polymer-based, paclitaxel-eluting TAXUS stents are effective in inhibiting neointimal tissue proliferation, and do not result in late incomplete stent apposition.

Evidence for a role of toll-like receptor 4 in development of chronic allograft rejection after cardiac transplantation

BACKGROUND

Long-term success of cardiac transplantation is limited by various forms of graft rejection. The specific mechanisms initiating and controlling these highly specialized immune processes remain unclear so far.

METHODS

To investigate the role of innate immunity in the development of allograft rejection, we assessed toll-like receptor (TLR)4 expression and typical downstream effects of TLR signaling (B7-1, interleukin [IL]-12, tumor necrosis factor [TNF]-alpha) in circulating CD14+ monocytes in 38 transplant recipients 1 to 3 years and in 10 transplant recipients 6 to 10 years after transplantation and compared them with 20 healthy controls using reverse transcription polymerase chain reaction, flow cytometry, and enzyme-linked immunoadsorbent assay. The results were matched with endothelial function testing as an early clinical indicator of transplant vasculopathy early after transplantation.

RESULTS

Allograft endothelial dysfunction (ED) was defined as a compromised coronary flow reserve (CFVR) to acetylcholine (CFVR<2 in 13 of 38 transplant recipients). In these patients, mRNA transcript levels for TLR4 (P<0.05) and surface expression of TLR4 (P<0.005) and B7-1 (P<0.05) on circulating monocytes as well as secretion of IL-12 (P<0.02) and TNF-alpha (P<0.05) were significantly higher than in the remaining 25 patients without ED. Compared with the controls, recipients late after transplantation did not show significantly elevated levels of TLR4 or dependent mediators. These results were compared with mRNA levels in a mice model of acute and chronic rejection. Rejecting mice exhibited elevated mRNA levels for mTLR4 and mB7-1.

CONCLUSIONS

Our results suggest activation of innate immunity in heart-transplant recipients through TLR4 contributes to the development of chronic rejection after cardiac transplantation.

Myosplint implant and shape-change procedure: intra- and peri-operative safety and feasibility

BACKGROUND

In patients with dilated cardiomyopathy (DCM), the heart enlarges, leading to a corresponding increase in ventricular wall stress. To reduce the stress, transventricular tension members (Myosplint, Myocor, Inc.) were implanted to change the left ventricle (LV) effective radius and to reduce the LV wall stress by 20%. We conducted this study to evaluate the intra- and peri-operative safety and feasibility of LV-shape change therapy.

METHODS

In 7 patients, all diagnosed with DCM, Myosplints were implanted. New York Heart Association class ranged from III-IV, and LV end-diastolic diameter ranged from 70 to 102 mm. Mitral valve regurgitation was classified as mild in 3 and moderate in 4 cases. Four patients underwent mitral valve annuloplasty.

RESULTS

We observed no significant device-related complications, such as thromboembolism, bleeding, device instability, or vascular damage, at 90 days. Early indications in a small patient population demonstrate some improvements in clinical parameters.

CONCLUSIONS

From this initial experience, one may conclude that placement of the Myosplint devices can be safely performed without early, significant adverse events. In patients with significant mitral valve incompetence, concomitant mitral valve repair is indicated to realize the full benefit of the procedure. This study also suggests that Myosplints can be safely implanted in combination with mitral valve repair. The long-term effect of each procedure on cardiac function and survival will require further evaluation.

Role of brain natriuretic peptide in risk stratification of patients with congestive heart failure

OBJECTIVES

Using a prospective study design, we assessed the value of brain natriuretic peptide (BNP) to identify patients with heart failure who have an increased risk of deterioration of their functional status. Furthermore, we examined the relationship between BNP and various clinical characteristics incorporated into an established survival model used for risk stratification.

BACKGROUND

Prediction of the clinical course is a crucial part of the decision-making process about the adequate treatment strategy for patients with advanced congestive heart failure (CHF). Although laborious, multivariable indexes have been established for risk stratification, simple plasma BNP measurements may be as useful as prognostic indicators.

METHODS

In 78 patients referred to our heart failure clinic, plasma BNP levels were compared with the results of a multivariable prognostic model. To assess the prognostic power of BNP, the clinical course of this cohort was monitored for a median follow-up period of 398 days.

RESULTS

At study entry, plasma BNP and the heart failure survival score (HFSS) showed a significant correlation (r = -0.706). During follow-up, Kaplan-Meier estimates of freedom from clinical events differed significantly for patients above and below the 75th percentile concentrations of plasma BNP (p < 0.0001). Changes in plasma BNP were significantly related to changes in limitations of physical activity, as demonstrated by logistic regression analysis (chi-square statistic = 24.9, p < 0.0001). Proportional hazards analysis confirmed BNP as a powerful predictor of functional status deterioration (p < 0.0001). This prognostic information was as powerful as that derived from the multivariable HFSS.

CONCLUSIONS

Measurement of plasma BNP concentrations might provide a useful and cost-effective screening tool that helps reduce the need and frequency for more expensive cardiac tests.

Pathogenetic mechanisms of cardiac allograft vasculopathy--impact of nitric oxide

In the cytokine-enriched environment of the chronically rejecting allograft, nitric oxide (NO) is predominantly produced by the inducible isoform of NOS synthase (NOS2) expressed by recipient-derived infiltrating immune cells as well as donor-derived vascular smooth muscle cells and endothelial cells. Early and persistent upregulation of NOS2 in allografts with cardiac allograft vasculopathy and downregulation of NOS2 coinciding with immunosuppressive attenuation of cardiac allograft vasculopathy have suggested NO as a regulator of cardiac allograft vasculopathy, the hallmark of chronic rejection. Pathogenetically, the development of cardiac allograft vasculopathy can be divided into an early phase, characterized by endothelial dysfunction, and a later phase, characterized by structural changes of vessel wall morphology. Several lines of evidence have shown that NO might play an essential role in both phases. Endothelial dysfunction due to immune-mediated injury of endothelial cells has been suggested as an early response-to-injury event in the pathogenesis of cardiac allograft vasculopathy. Functional studies in human transplant recipients have documented endothelial dysfunction of coronary artery vessels. Administration of L-arginine, the precursor of NO, improved endothelial function of both epicardial coronary arteries and coronary microvasculature indicating a protective effect of NO. To assess the impact of NO on the development of late structural changes, the severity of cardiac allograft vasculopathy was assessed in mice with targeted deletion of NOS2. A significant increase of vascular occlusion in NOS2-knockout mice demonstrated an antiarteriosclerotic effect of NOS2. In part, this effect could be explained by reduced neointimal smooth muscle cell accumulation after alloimmune injury. Taken together, NO plays an important role in maintaining vessel integrity after transplantation. Disruptions in NO pathways seem to play a key role in the progression from endothelial dysfunction to structural changes.