Clinical Validation of a Machine-Learned, Point-of-Care System to IDENTIFY Functionally Significant Coronary Artery Disease.

Many clinical studies have shown wide performance variation in tests to identify coronary artery disease (CAD). Coronary computed tomography angiography (CCTA) has been identified as an effective rule-out test but is not widely available in the USA, particularly so in rural areas. Patients in rural areas are underserved in the healthcare system as compared to urban areas, rendering it a priority population to target with highly accessible diagnostics. We previously developed a machine-learned algorithm to identify the presence of CAD (defined by functional significance) in patients with symptoms without the use of radiation or stress. The algorithm requires 215 s temporally synchronized photoplethysmographic and orthogonal voltage gradient signals acquired at rest. The purpose of the present work is to validate the performance of the algorithm in a frozen state (i.e., no retraining) in a large, blinded dataset from the IDENTIFY trial. IDENTIFY is a multicenter, selectively blinded, non-randomized, prospective, repository study to acquire signals with paired metadata from subjects with symptoms indicative of CAD within seven days prior to either left heart catheterization or CCTA. The algorithm's sensitivity and specificity were validated using a set of unseen patient signals (n = 1816). Pre-specified endpoints were chosen to demonstrate a rule-out performance comparable to CCTA. The ROC-AUC in the validation set was 0.80 (95% CI: 0.78-0.82). This performance was maintained in both male and female subgroups. At the pre-specified cut point, the sensitivity was 0.85 (95% CI: 0.82-0.88), and the specificity was 0.58 (95% CI: 0.54-0.62), passing the pre-specified endpoints. Assuming a 4% disease prevalence, the NPV was 0.99. Algorithm performance is comparable to tertiary center testing using CCTA. Selection of a suitable cut-point results in the same sensitivity and specificity performance in females as in males. Therefore, a medical device embedding this algorithm may address an unmet need for a non-invasive, front-line point-of-care test for CAD (without any radiation or stress), thus offering significant benefits to the patient, physician, and healthcare system.

Economic outcomes of percutaneous coronary intervention with drug-eluting stents versus bypass surgery for patients with left main or three-vessel coronary artery disease: one-year results from the SYNTAX trial.

OBJECTIVES: To evaluate the cost-effectiveness of alternative approaches to revascularization for patients with three-vessel or left main coronary artery disease (CAD). BACKGROUND: Previous studies have demonstrated that, despite higher initial costs, long-term costs with bypass surgery (CABG) in multivessel CAD are similar to those for percutaneous coronary intervention (PCI). The impact of drug-eluting stents (DES) on these results is unknown. METHODS: The SYNTAX trial randomized 1,800 patients with left main or three-vessel CAD to either CABG (n = 897) or PCI using paclitaxel-eluting stents (n = 903). Resource utilization data were collected prospectively for all patients, and cumulative 1-year costs were assessed from the perspective of the U.S. healthcare system. RESULTS: Total costs for the initial hospitalization were $5,693/patient higher with CABG, whereas follow-up costs were $2,282/patient higher with PCI due mainly to more frequent revascularization procedures and higher outpatient medication costs. Total 1-year costs were thus $3,590/patient higher with CABG, while quality-adjusted life expectancy was slightly higher with PCI. Although PCI was an economically dominant strategy for the overall population, cost-effectiveness varied considerably according to angiographic complexity. For patients with high angiographic complexity (SYNTAX score > 32), total 1-year costs were similar for CABG and PCI, and the incremental cost-effectiveness ratio for CABG was $43,486 per quality-adjusted life-year gained. CONCLUSIONS: Among patients with three-vessel or left main CAD, PCI is an economically attractive strategy over the first year for patients with low and moderate angiographic complexity, while CABG is favored among patients with high angiographic complexity.

Impact of obesity on revascularization and restenosis rates after bare-metal and drug-eluting stent implantation (from the TAXUS-IV trial).

The effect of obesity on repeat coronary revascularization and restenosis in patients who undergo stent implantation has not been reported. We therefore examined the database from the multicenter randomized TAXUS-IV trial to determine the effect of body mass index (BMI) on outcomes after bare-metal and drug-eluting stent implantation. In TAXUS-IV, patients were randomized to receive a slow-release, polymer-based, paclitaxel-eluting stent or a bare-metal stent. Outcomes were stratified by baseline BMI. Of the 1,307 randomized patients who had documented BMI, 233 (17.8%) had normal weight (BMI <25 kg/m2), 531 (40.6%) were overweight (BMI < or =25 to 30 kg/m2), and 543 (41.5%) were obese (BMI > or =30 kg/m2). Patients who had been assigned to receive bare-metal stents and were overweight and obese compared with those who had normal weight had higher rates of 9-month binary restenosis (29.2% and 30.5% vs 9.3%, respectively; p = 0.01) and 1-year major adverse cardiac events (20.8% and 23.2% vs 11.1%, respectively; p = 0.02), whereas rates of these events did not differ significantly among those who received a paclitaxel-eluting stent (7.6% and 9.3% vs 4.9%, respectively for binary restenosis; p = 0.65; 11.3% and 10.4% vs 10.1%, respectively; p = 0.82 for major adverse cardiac events). By multivariate analysis, BMI > or =30.0 kg/m2 independently predicted binary restenosis (hazard ratio 4.26, p = 0.005), 1-year target vessel revascularization (hazard ratio 1.95, p = 0.04), and major adverse cardiac events (hazard ratio 1.95, p = 0.004) in patients who received bare-metal stents but not paclitaxel-eluting stents. In conclusion, obesity is an important risk factor for clinical and angiographic restenosis and for composite major adverse cardiac events in patients who receive bare-metal stents. Paclitaxel-eluting stents attenuate the increased risk associated with obesity, such that the intermediate-term prognosis after percutaneous coronary intervention is independent of weight.

Improved strut coverage and less late incomplete apposition with thin-strut TAXUS Liberté vs. TAXUS Express: the importance of stent platform design for drug-eluting stents.

BACKGROUND: The objective of this intravascular ultrasound (IVUS) analysis was to evaluate the vascular response of the thin-strut TAXUS Liberté stent compared with the otherwise identical TAXUS Express stent. METHODS AND MATERIALS: The TAXUS ATLAS and TAXUS ATLAS Long Lesion studies are nonrandomized trials comparing the thin-strut TAXUS Liberté stent to historical TAXUS Express controls from the TAXUS IV and TAXUS V trials. A total of 377 patients enrolled in the two TAXUS ATLAS studies were randomly selected for the IVUS subset and compared to 314 TAXUS Express IVUS controls. RESULTS: Despite increased lesion complexity in the TAXUS Liberté group, neointimal formation at 9 months was similar in both stents (TAXUS Liberté 13.8±11.0%; TAXUS Express 13.1±13.8%, P=.56). However, this neointima covered more of the overall stent in the TAXUS Liberté (67.9±32.5%) compared with the TAXUS Express (54.4±37.2%, P<.001), suggesting more uniform neointimal distribution. TAXUS Liberté also showed less pronounced negative remodeling at both stent edges and had significantly less (4.3% vs. 9.6%, P=.04) late incomplete stent apposition (ISA). CONCLUSIONS: Despite identical polymer and drug release characteristic, the thin-strut TAXUS Liberté stent demonstrates improved neointimal coverage, better edge remodeling, and less late ISA vs. TAXUS Express, hereby highlighting the importance of the platform design for drug-eluting stents.

TAXUS Liberté attenuates the risk of restenosis in patients with medically treated diabetes mellitus: results from the TAXUS ATLAS program.

OBJECTIVES: The aim of this study was to assess the relative efficacy and safety of the second-generation TAXUS Liberté paclitaxel-eluting stent (PES) in patients with and without diabetes mellitus. BACKGROUND: Diabetic patients suffer from accelerated atherosclerosis and increased risk of restenosis after coronary interventions; however, prior data suggest that PES might blunt this effect, providing equal benefit in diabetic and nondiabetic patients. METHODS: A pooled analysis of all 4 TAXUS ATLAS studies was conducted that included 413 diabetic and 1,116 nondiabetic subjects treated with the TAXUS Liberté stent for de novo coronary lesions. Angiographic and intravascular ultrasound outcomes at 9 months and clinical outcomes at 9 and 12 months were compared in patients with and without diabetes. Propensity score and multivariate adjustments were performed to correct for baseline differences. RESULTS: In-stent angiographic restenosis (13.0% vs. 9.6%, p = 0.12), late luminal loss (0.40 mm vs. 0.38 mm, p = 0.58), and intimal hyperplasia (14.8% vs. 13.4%, p = 0.29) were similar for diabetic and nondiabetic subjects. After propensity adjustment, 12-month target lesion revascularization rates were similar for diabetic and nondiabetic subjects (6.4% vs. 4.7%, p = 0.18), with no differences in mortality, myocardial infarction, or stent thrombosis. However, the rate of target vessel revascularization (TVR) was higher for diabetic subjects due to increased TVR outside the target lesion (TVR Remote). CONCLUSIONS: Similar clinical, angiographic, and intravascular ultrasound outcomes were observed for both diabetic and nondiabetic subjects treated with TAXUS Liberté, suggesting that this PES attenuates the effect of diabetes on restenosis after percutaneous coronary intervention, yielding comparable efficacy and safety in diabetic and nondiabetic patients. (TAXUS ATLAS; NCT00371709, NCT00371423, NCT00371748, and NCT00371475).

Reduced risk of restenosis in small vessels and reduced risk of myocardial infarction in long lesions with the new thin-strut TAXUS Liberté stent: 1-year results from the TAXUS ATLAS program.

OBJECTIVES: The TAXUS ATLAS Small Vessel (SV) and Long Lesion (LL) multicenter studies compared the performance of the thin-strut (0.0038 inch) TAXUS Liberté 2.25-mm stent (Boston Scientific; Natick, Massachusetts) and the TAXUS Liberté 38-mm long stent (Boston Scientific; Natick, Massachusetts) with the earlier paclitaxel-eluting TAXUS Express (Boston Scientific) stent that has identical polymer, drug dosage, and release kinetics but different stent geometry and thicker struts (0.0052 inch). BACKGROUND: The TAXUS Liberté stent was designed with thinner and more even strut spacing to provide more uniform drug distribution, as well as increased flexibility and conformability. Clinical benefits of the new stent design have not been evaluated. METHODS: The TAXUS ATLAS SV and LL studies are nonrandomized studies comparing outcomes of the TAXUS Liberté 2.25 mm (N = 261) and TAXUS Liberté 38 mm (N = 150) stents to TAXUS Express historical control groups derived from the TAXUS IV and V trials. Inclusion/exclusion criteria for TAXUS Express and Liberté groups were similar in both studies. RESULTS: Each study met its primary end point of noninferiority of 9-month in-segment diameter stenosis. Furthermore, TAXUS Liberté 2.25 mm, when compared with TAXUS Express, significantly reduced the rate of both 9-month angiographic restenosis (18.5% vs. 32.7%, p = 0.0219) and 12-month target lesion revascularization (6.1% vs. 16.9%, p = 0.0039). In addition, TAXUS Liberté 38 mm significantly reduced the risk of 12-month myocardial infarction compared with TAXUS Express (1.4% vs. 6.5%, p = 0.0246). CONCLUSIONS: The thinner-strut TAXUS Liberté stent improved outcomes compared with the earlier TAXUS Express stent in both SVs and LLs (A Study of the TAXUS Liberté Stent for the Treatment of de Novo Coronary Artery Lesions in Small Vessels; NCT00371748; A Study of the TAXUS Liberté Stent for the Treatment of Long De Novo Coronary Artery Lesions; NCT00371475).

Polymer-based, paclitaxel-eluting TAXUS Liberté stent in de novo lesions: the pivotal TAXUS ATLAS trial.

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).