John L. Petersen

Transcatheter Aortic-Valve Implantation for Aortic Stenosis in Patients Who Cannot Undergo Surgery

BACKGROUND Many patients with severe aortic stenosis and coexisting conditions are not candidates for surgical replacement of the aortic valve. Recently, transcatheter aortic-valve implantation (TAVI) has been suggested as a less invasive treatment for high-risk patients with aortic stenosis. METHODS We randomly assigned patients with severe aortic stenosis, whom surgeons considered not to be suitable candidates for surgery, to standard therapy (including balloon aortic valvuloplasty) or transfemoral transcatheter implantation of a balloon-expandable bovine pericardial valve. The primary end point was the rate of death from any cause. RESULTS A total of 358 patients with aortic stenosis who were not considered to be suitable candidates for surgery underwent randomization at 21 centers (17 in the United States). At 1 year, the rate of death from any cause (Kaplan–Meier analysis) was 30.7% with TAVI, as compared with 50.7% with standard therapy (hazard ratio with TAVI, 0.55; 95% confidence interval [CI], 0.40 to 0.74; P<0.001). The rate of the composite end point of death from any cause or repeat hospitalization was 42.5% with TAVI as compared with 71.6% with standard therapy (hazard ratio, 0.46; 95% CI, 0.35 to 0.59; P<0.001). Among survivors at 1 year, the rate of cardiac symptoms (New York Heart Association class III or IV) was lower among patients who had undergone TAVI than among those who had received standard therapy (25.2% vs. 58.0%, P<0.001). At 30 days, TAVI, as compared with standard therapy, was associated with a higher incidence of major strokes (5.0% vs. 1.1%, P=0.06) and major vascular complications (16.2% vs. 1.1%, P<0.001). In the year after TAVI, there was no deterioration in the functioning of the bioprosthetic valve, as assessed by evidence of stenosis or regurgitation on an echocardiogram. CONCLUSIONS In patients with severe aortic stenosis who were not suitable candidates for surgery, TAVI, as compared with standard therapy, significantly reduced the rates of death from any cause, the composite end point of death from any cause or repeat hospitalization, and cardiac symptoms, despite the higher incidence of major strokes and major vascular events. (Funded by Edwards Lifesciences; ClinicalTrials.gov number, NCT00530894.).

Standardized Endpoint Definitions for Transcatheter Aortic Valve Implantation Clinical Trials

OBJECTIVES To propose standardized consensus definitions for important clinical endpoints in transcatheter aortic valve implantation (TAVI), investigations in an effort to improve the quality of clinical research and to enable meaningful comparisons between clinical trials. To make these consensus definitions accessible to all stakeholders in TAVI clinical research through a peer reviewed publication, on behalf of the public health. BACKGROUND Transcatheter aortic valve implantation may provide a worthwhile less invasive treatment in many patients with severe aortic stenosis and since its introduction to the medical community in 2002, there has been an explosive growth in procedures. The integration of TAVI into daily clinical practice should be guided by academic activities, which requires a harmonized and structured process for data collection, interpretation, and reporting during well-conducted clinical trials. METHODS AND RESULTS The Valve Academic Research Consortium established an independent collaboration between Academic Research organizations and specialty societies (cardiology and cardiac surgery) in the USA and Europe. Two meetings, in San Francisco, California (September 2009) and in Amsterdam, the Netherlands (December 2009), including key physician experts, and representatives from the U.S. Food and Drug Administration (FDA) and device manufacturers, were focused on creating consistent endpoint definitions and consensus recommendations for implementation in TAVI clinical research programs. Important considerations in developing endpoint definitions included: 1) respect for the historical legacy of surgical valve guidelines; 2) identification of pathophysiological mechanisms associated with clinical events; 3) emphasis on clinical relevance. Consensus criteria were developed for the following endpoints: mortality, myocardial infarction, stroke, bleeding, acute kidney injury, vascular complications, and prosthetic valve performance. Composite endpoints for TAVI safety and effectiveness were also recommended. CONCLUSIONS Although consensus criteria will invariably include certain arbitrary features, an organized multidisciplinary process to develop specific definitions for TAVI clinical research should provide consistency across studies that can facilitate the evaluation of this new important catheter-based therapy. The broadly based consensus endpoint definitions described in this document may be useful for regulatory and clinical trial purposes.

Randomized Comparison of Everolimus-Eluting and Paclitaxel-Eluting Stents : Two-Year Clinical Follow-Up From the Clinical Evaluation of the Xience V Everolimus Eluting Coronary Stent System in the Treatment of Patients With De Novo Native Coronary Artery Lesions (SPIRIT) III Trial

Background— In the prospective randomized Clinical Evaluation of the Xience V Everolimus Eluting Coronary Stent System in the Treatment of Patients with de novo Native Coronary Artery Lesions (SPIRIT) III trial, an everolimus-eluting stent (EES) compared with a widely used paclitaxel-eluting stent (PES) resulted in a statistically significant reduction in angiographic in-segment late loss at 8 months and noninferior rates of target vessel failure (cardiac death, myocardial infarction, or target vessel revascularization) at 1 year. The safety and efficacy of EES after 1 year have not been reported. Methods and Results— A total of 1002 patients with up to 2 de novo native coronary artery lesions (reference vessel diameter, 2.5 to 3.75 mm; lesion length ≤28 mm) were randomized 2:1 to EES versus PES. Antiplatelet therapy consisted of aspirin indefinitely and a thienopyridine for ≥6 months. Between 1 and 2 years, patients treated with EES compared with PES tended to have fewer episodes of protocol-defined stent thrombosis (0.2% versus 1.0%; P=0.10) and myocardial infarctions (0.5% versus 1.7%; P=0.12), with similar rates of cardiac death (0.3% versus 0.3%; P=1.0) and target vessel revascularization (2.9% versus 3.0%; P=1.0). As a result, at the completion of the 2-year follow-up, treatment with EES compared with PES resulted in a significant 32% reduction in target vessel failure (10.7% versus 15.4%; hazard ratio, 0.68; 95% confidence interval, 0.48 to 0.98; P=0.04) and a 45% reduction in major adverse cardiac events (cardiac death, myocardial infarction, or target lesion revascularization; 7.3% versus 12.8%; hazard ratio, 0.55; 95% confidence interval, 0.36 to 0.83; P=0.004). Among the 360 patients who discontinued clopidogrel or ticlopidine after 6 months, stent thrombosis subsequently developed in 0.4% of EES patients versus 2.6% of PES patients (P=0.10). Conclusions— Patients treated with EES rather than PES experienced significantly improved event-free survival at a 2-year follow-up in the SPIRIT III trial, with continued divergence of the hazard curves for target vessel failure and major adverse cardiac events between 1 and 2 years evident. The encouraging trends toward fewer stent thrombosis episodes after 6 months in EES-treated patients who discontinued a thienopyridine and after 1 year in all patients treated with EES rather than PES deserve further study.

In vivo validation of a catheter-based near-infrared spectroscopy system for detection of lipid core coronary plaques: initial results of the SPECTACL study.

OBJECTIVES To determine whether catheter-based near-infrared spectroscopy (NIRS) signals obtained with a novel catheter-based system from coronaries of patients are similar to those from autopsy specimens and to assess initial safety of NIRS device. BACKGROUND An intravascular NIRS system for detection of lipid core-containing plaques (LCP) has been validated in human coronary autopsy specimens. The SPECTACL (SPECTroscopic Assessment of Coronary Lipid) trial was a parallel first-in-human multicenter study designed to demonstrate the applicability of the LCP detection algorithm in living patients. METHODS Intracoronary NIRS was performed in patients undergoing percutaneous coronary intervention. Acquired spectra were blindly compared with autopsy NIRS signals with multivariate statistics. To meet the end point of spectral similarity, at least two-thirds of the scans were required to have >80% of spectra similar to the autopsy spectra. RESULTS A total of 106 patients were enrolled; there were no serious adverse events attributed to NIRS. Spectroscopic data could not be obtained in 17 (16%) patients due to technical limitations, leaving 89 patients for analysis. Spectra from 30 patients were unblinded to test the calibration of the LCP detection algorithm. Of the remaining 59 blinded cases, after excluding 11 due to inadequate data, spectral similarity was demonstrated in 40 of 48 spectrally adequate scans (83% success rate, 95% confidence interval: 70% to 93%, median spectral similarity/pullback: 96%, interquartile range 10%). The LCP was detected in 58% of 60 spectrally similar scans from both cohorts. CONCLUSIONS This intravascular NIRS system safely obtained spectral data in patients that were similar to those from autopsy specimens. These results demonstrate the feasibility of invasive detection of coronary LCP with this novel system. (SPECTACL: SPECTroscopic Assessment of Coronary Lipid; NCT00330928).

Impaired glucose tolerance and impaired fasting glucose--a review of diagnosis, clinical implications and management.

The diagnostic categories of impaired glucose tolerance (IGT) and impaired fasting glucose (IFG) were established in an effort to identify populations at risk for developing type 2 diabetes mellitus (T2DM). Both IGT and IFG are associated with increased risk of developing T2DM, but recent analyses found that the thresholds of risk vary among different populations and an even lower diagnostic threshold of IFG may be appropriate. IGT has been linked with an increased risk of cardiovascular events and some analyses have demonstrated an increased mortality risk compared with patients with normal glucose tolerance. In contrast, a continuum of increased risk of microvascular manifestations of T2DM has been demonstrated with IFG but an association of IFG with cardiovascular events has not been well established. Although both IGT and IFG are associated with resistance to insulin and increased insulin secretion, they do not identify the identical patient populations and are not equivalent in predicting development of T2DM or cardiovascular events. IFG and IGT have been associated with other features of insulin resistance, including dyslipidaemia, hypertension, abdominal obesity, microalbuminuria, endothelial dysfunction, and markers of inflammation and hypercoagulability, traits collectively referred to as the metabolic syndrome. Analyses of combinations of these components have also been associated with progression to T2DM, cardiovascular disease and increased mortality. The foundation of treatment for IGT, IFG, and the metabolic syndrome is lifestyle modification, including both dietary change and routine exercise. To date, several clinical trials have found that lifestyle modification is the most efficacious strategy to prevent progression to T2DM. Alternative treatments include pharmacotherapy with metformin or acarbose, both of which have been demonstrated to decrease the development of T2DM. Ongoing clinical trials are evaluating newer pharmacotherapies, including angiotensin converting enzyme inhibitors, angiotensin receptor antagonists, metglitinides and thiazolidinediones, to prevent both T2DM and cardiovascular events. In combination with lifestyle modification, these therapies offer hope for effective prevention of T2DM and its consequences in high-risk patients.

A novel bioresorbable polymer paclitaxel-eluting stent for the treatment of single and multivessel coronary disease: primary results of the COSTAR (Cobalt Chromium Stent With Antiproliferative for Restenosis) II study.

OBJECTIVES The aim was to compare safety and effectiveness of the CoStar drug-eluting stent (DES) (Conor MedSystems, Menlo Park, California) with those of the Taxus DES (Boston Scientific, Maple Grove, Minnesota) in de novo single- and multivessel percutaneous coronary intervention (PCI). BACKGROUND Paclitaxel elution from a stent coated with biostable polymer (Taxus) reduces restenosis after PCI. The CoStar DES is a novel stent with laser-cut reservoirs containing bioresorbable polymer loaded to elute 10 microg paclitaxel/30 days. METHODS Patients undergoing PCI for a single target lesion per vessel in up to 3 native epicardial vessels were randomly assigned 3:2 to CoStar or Taxus. Primary end point was 8-month major adverse cardiac events (MACE), defined as adjudicated death, myocardial infarction (MI), or clinically driven target vessel revascularization (TVR). Protocol-specified 9-month angiographic follow-up included 457 vessels in 286 patients. RESULTS Of the 1,700 patients enrolled, 1,675 (98.5%) were evaluable (CoStar = 989; Taxus = 686), including 1,330 (79%) single-vessel and 345 (21%) multivessel PCI. The MACE rate at 8 months was 11.0% for CoStar versus 6.9% for Taxus (p < 0.005), including adjudicated death (0.5% vs. 0.7%, respectively), MI (3.4% vs. 2.4%, respectively), and TVR (8.1% vs. 4.3%, respectively). Per-vessel 9-month in-segment late loss was 0.49 mm with CoStar and 0.18 mm with Taxus (p < 0.0001). Findings were consistent across pre-specified subgroups. CONCLUSIONS The CoStar DES is not noninferior to the Taxus DES based on per-patient clinical and per-vessel angiographic analyses. The relative benefit of Taxus is primarily attributable to reduction in TVR. Follow-up to 9 months showed no apparent difference in death, MI, or stent thrombosis rates.

Detection by Near-Infrared Spectroscopy of Large Lipid Core Plaques at Culprit Sites in Patients With Acute ST-Segment Elevation Myocardial Infarction

OBJECTIVES This study sought to describe near-infrared spectroscopy (NIRS) findings of culprit lesions in ST-segment elevation myocardial infarction (STEMI). BACKGROUND Although autopsy studies demonstrate that most STEMI are caused by rupture of pre-existing lipid core plaque (LCP), it has not been possible to identify LCP in vivo. A novel intracoronary NIRS catheter has made it possible to detect LCP in patients. METHODS We performed NIRS within the culprit vessels of 20 patients with acute STEMI and compared the STEMI culprit findings to findings in nonculprit segments of the artery and to findings in autopsy control segments. Culprit and control segments were analyzed for the maximum lipid core burden index in a 4-mm length of artery (maxLCBI(4mm)). RESULTS MaxLCBI(4mm) was 5.8-fold higher in STEMI culprit segments than in 87 nonculprit segments of the STEMI culprit vessel (median [interquartile range (IQR)]: 523 [445 to 821] vs. 90 [6 to 265]; p < 0.001) and 87-fold higher than in 279 coronary autopsy segments free of large LCP by histology (median [IQR]: 523 [445 to 821] vs. 6 [0 to 88]; p < 0.001).Within the STEMI culprit artery, NIRS accurately distinguished culprit from nonculprit segments (receiver-operating characteristic analysis area under the curve = 0.90). A threshold of maxLCBI(4mm) >400 distinguished STEMI culprit segments from specimens free of large LCP by histology (sensitivity: 85%, specificity: 98%). CONCLUSIONS The present study has demonstrated in vivo that a maxLCBI(4mm) >400, as detected by NIRS, is a signature of plaques causing STEMI.

Standardized reporting of bleeding complications for clinical investigations in acute coronary syndromes: a proposal from the academic bleeding consensus (ABC) multidisciplinary working group.

BACKGROUND Clinical trials of antithrombotic agents for the treatment of ACS routinely assess bleeding as a safety endpoint, but variation in bleeding definitions makes comparison of the relative safety of these agents difficult. METHODS The ABC Multidisciplinary Working Group, an informal working group comprising clinical researchers and representatives from the US Food and Drug Administration, the National Institutes of Health, and the pharmaceutical industry, sought to develop a consensus approach to measuring the incidence and severity of bleeding complications during clinical trials of acute coronary syndromes (ACS). A meeting of the ABC was convened in April 2008 in Washington, DC, with the goal of developing a consensus approach to measuring the incidence and severity of hemorrhagic complications during clinical trials of ACS. Relevant literature on bleeding was reviewed through a series of short lectures and intensive group discussion. RESULTS Using existing evidence on bleeding and outcomes as well as clinical judgment, criteria for the assessment of bleeding were developed through expert consensus. This consensus statement divides bleeding-related data elements into three categories: essential, recommended, and optional. CONCLUSIONS The ABC Group recommendations for collection and reporting of bleeding complications provide a framework for consistency in the collection of information on hemorrhagic complications in trials of ACS. Widespread adoption of the statement recommendations will facilitate understanding of the mechanisms of adverse outcomes after bleeding and comparisons of the relative safety of antithrombotic agents, as well as the interpretation of safety results from future studies.

Autopsy Validation Study of the Academic Research Consortium Stent Thrombosis Definition

OBJECTIVES This study sought to validate the sensitivity and specificity of the Academic Research Consortiums (ARC) classification of stent thrombosis. BACKGROUND Classification of stent thrombosis according to ARC criteria has become widely accepted. The criteria have not been validated against an autopsy standard. METHODS An autopsy registry of 139 subjects with prior coronary stenting underwent detailed histopathological analysis to assess for stent thrombosis. Based on clinical data only, cases were adjudicated according to ARC stent thrombosis criteria, including a proposed modification of the possible classification to include death beyond 30 days due only to sudden death or acute ischemia. RESULTS Autopsy results confirmed 51 cases as positive and 88 as negative for stent thrombosis. Clinical adjudication classified 105 cases as definite (10), probable (31), or possible (64) ARC stent thrombosis. Specificity was high for definite (99%) and definite plus probable (83%) criteria, but sensitivity was poor at 18% and 51%, respectively. Including the possible cases improved sensitivity to 92% but reduced specificity to 34% (58 false positives). The modified possible criteria eliminated 13 false positive cases (specificity = 49%) and was the best approximation of a hypothetical gold standard in a sensitivity analysis if late death represented at least 20% of all stent thrombosis cases. CONCLUSIONS In a selected autopsy sample, restricting ARC stent thrombosis to definite or definite plus probable criteria results in substantial under-reporting of confirmed cases. Inclusion of a modified possible classification may provide the best estimate of late and very late stent thrombosis rates.

Clopidogrel use and clinical events after drug-eluting stent implantation: Findings from the HealthCore Integrated Research Database

BACKGROUND Relationships between long-term use and level of dual antiplatelet therapy and outcomes after drug-eluting stent implantation are not well established. METHODS This is a retrospective cohort study of 9,256 patients receiving drug-eluting stents between January 2003 and August 2006. We classified patients according to tertiles of clopidogrel use during the 12 months after stent implantation. We used inverse probability weighting to account for differential selection into levels of clopidogrel use and logistic regression to estimate propensity scores for levels of clopidogrel use. We used Cox proportional hazards models to estimate effects of level of clopidogrel use on risk of bleeding events, death, and death or nonfatal myocardial infarction. RESULTS There were 3,102 patients in the high-use group, 3,069 in the medium-use group, and 3,085 in the low-use group. Compared with the high-use group, risk of death or nonfatal myocardial infarction was greater in the medium-use group (hazard ratio [HR] 1.46, 95% CI 1.09-1.99, P = .01) and the low-use group (HR 1.59, 95% CI 1.18-2.14, P = .002). The risk of bleeding events was lower in the medium-use group (HR 0.84, 95% CI 0.71-0.98, P = .03) and the low-use group (HR 0.77, 95% CI 0.65-0.90, P = .002). CONCLUSIONS Higher clopidogrel use 12 months after drug-eluting stent implantation was associated with a greater risk of subsequent bleeding events. Lower use was associated with a greater risk of death or nonfatal myocardial infarction.