Factors Associated With Trial Completion and Adherence in App-Based N-of-1 Trials: Protocol for a Randomized Trial Evaluating Study Duration, Notification Level, and Meaningful Engagement in the Brain Boost Study

Background

N-of-1 trials promise to help individuals make more informed decisions about treatment selection through structured experiments that compare treatment effectiveness by alternating treatments and measuring their impacts in a single individual. We created a digital platform that automates the design, administration, and analysis of N-of-1 trials. Our first N-of-1 trial, the app-based Brain Boost Study, invited individuals to compare the impacts of two commonly consumed substances (caffeine and L-theanine) on their cognitive performance.

Objective

The purpose of this study is to evaluate critical factors that may impact the completion of N-of-1 trials to inform the design of future app-based N-of-1 trials. We will measure study completion rates for participants that begin the Brain Boost Study and assess their associations with study duration (5, 15, or 27 days) and notification level (light or moderate).

Methods

Participants will be randomized into three study durations and two notification levels. To sufficiently power the study, a minimum of 640 individuals must begin the study, and 97 individuals must complete the study. We will use a multiple logistic regression model to discern whether the study length and notification level are associated with the rate of study completion. For each group, we will also compare participant adherence and the proportion of trials that yield statistically meaningful results.

Results

We completed the beta testing of the N1 app on a convenience sample of users. The Brain Boost Study on the N1 app opened enrollment to the public in October 2019. More than 30 participants enrolled in the first month.

Conclusions

To our knowledge, this will be the first study to rigorously evaluate critical factors associated with study completion in the context of app-based N-of-1 trials.

Trial Registration

ClinicalTrials.gov NCT04056650; https://clinicaltrials.gov/ct2/show/NCT04056650

International Registered Report Identifier (IRRID)

PRR1-10.2196/16362

Chemotherapy weakly contributes to predicted neoantigen expression in ovarian cancer

Background

Patients with highly mutated tumors, such as melanoma or smoking-related lung cancer, have higher rates of response to immune checkpoint blockade therapy, perhaps due to increased neoantigen expression. Many chemotherapies including platinum compounds are known to be mutagenic, but the impact of standard treatment protocols on mutational burden and resulting neoantigen expression in most human cancers is unknown.

Methods

We sought to quantify the effect of chemotherapy treatment on computationally predicted neoantigen expression for high grade serous ovarian carcinoma patients enrolled in the Australian Ovarian Cancer Study. In this series, 35 of 114 samples were collected after exposure to chemotherapy; 14 are matched with an untreated sample from the same patient. Our approach integrates whole genome and RNA sequencing of bulk tumor samples with class I MHC binding prediction and mutational signatures extracted from studies of chemotherapy-exposed Caenorhabditis elegans and Gallus gallus cells. We additionally investigated the relationship between neoantigens, tumor infiltrating immune cells estimated from RNA-seq with CIBERSORT, and patient survival.

Results

Greater neoantigen burden and CD8+ T cell infiltration in primary, pre-treatment samples were independently associated with improved survival. Relapse samples collected after chemotherapy harbored a median of 78% more expressed neoantigens than untreated primary samples, a figure that combines the effects of chemotherapy and other processes operative during relapse. The contribution from chemotherapy-associated signatures was small, accounting for a mean of 5% (range 0–16) of the expressed neoantigen burden in relapse samples. In both treated and untreated samples, most neoantigens were attributed to COSMIC Signature (3), associated with BRCA disruption, Signature (1), associated with a slow mutagenic process active in healthy tissue, and Signature (8), of unknown etiology.

Conclusion

Relapsed ovarian cancers harbor more predicted neoantigens than primary tumors, but the increase is due to pre-existing mutational processes, not mutagenesis from chemotherapy.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-017-3825-0) contains supplementary material, which is available to authorized users.

Comprehensive search for Alzheimer disease susceptibility loci in the APOE region

OBJECTIVE

To evaluate the association of risk and age at onset (AAO) of Alzheimer disease (AD) with single-nucleotide polymorphisms (SNPs) in the chromosome 19 region including apolipoprotein E (APOE) and a repeat-length polymorphism in TOMM40 (poly-T, rs10524523).

DESIGN

Conditional logistic regression models and survival analysis.

SETTING

Fifteen genome-wide association study data sets assembled by the Alzheimer's Disease Genetics Consortium.

PARTICIPANTS

Eleven thousand eight hundred forty AD cases and 10 931 cognitively normal elderly controls.

MAIN OUTCOME MEASURES

Association of AD risk and AAO with genotyped and imputed SNPs located in an 800-Mb region including APOE in the entire Alzheimer's Disease Genetics Consortium data set and with the TOMM40 poly-T marker genotyped in a subset of 1256 cases and 1605 controls.

RESULTS

In models adjusting for APOE ε4, no SNPs in the entire region were significantly associated with AAO at P.001. Rs10524523 was not significantly associated with AD or AAO in models adjusting for APOE genotype or within the subset of ε3/ε3 subjects.

CONCLUSIONS

APOE alleles ε2, ε3, and ε4 account for essentially all the inherited risk of AD associated with this region. Other variants including a poly-T track in TOMM40 are not independent risk or AAO loci.

δ-Catenin is genetically and biologically associated with cortical cataract and future Alzheimer-related structural and functional brain changes

Multiple lines of evidence suggest that specific subtypes of age-related cataract (ARC) and Alzheimer disease (AD) are related etiologically. To identify shared genetic factors for ARC and AD, we estimated co-heritability of quantitative measures of cataract subtypes with AD-related brain MRI traits among 1,249 members of the Framingham Eye Study who had a brain MRI scan approximately ten years after the eye exam. Cortical cataract (CC) was found to be co-heritable with future development of AD and with several MRI traits, especially temporal horn volume (THV, ρ = 0.24, P<10(-4)). A genome-wide association study using 187,657 single nucleotide polymorphisms (SNPs) for the bivariate outcome of CC and THV identified genome-wide significant association with CTNND2 SNPs rs17183619, rs13155993 and rs13170756 (P<2.6 × 10(-7)). These SNPs were also significantly associated with bivariate outcomes of CC and scores on several highly heritable neuropsychological tests (5.7 × 10(-9) ≤ P<3.7 × 10(-6)). Statistical interaction was demonstrated between rs17183619 and APP SNP rs2096488 on CC (P = 0.0015) and CC-THV (P = 0.038). A rare CTNND2 missense mutation (G810R) 249 base pairs from rs17183619 altered δ-catenin localization and increased secreted amyloid-β(1-42) in neuronal cell culture. Immunohistopathological analysis of lens tissue obtained from two autopsy-confirmed AD subjects and two non-AD controls revealed elevated expression of δ-catenin in epithelial and cortical regions of lenses from AD subjects compared to controls. Our findings suggest that genetic variation in delta catenin may underlie both cortical lens opacities in mid-life and subsequent MRI and cognitive changes that presage the development of AD.

Multiple loci influencing hippocampal degeneration identified by genome scan

OBJECTIVE

Large genome-wide association studies (GWASs) have identified many novel genes influencing Alzheimer disease (AD) risk, but most of the genetic variance remains unexplained. We conducted a 2-stage GWAS for AD-related quantitative measures of hippocampal volume (HV), total cerebral volume (TCV), and white matter hyperintensities (WMH).

METHODS

Brain magnetic resonance imaging measures of HV, TCV, and WMH were obtained from 981 Caucasian and 419 African American AD cases and their cognitively normal siblings in the MIRAGE (Multi Institutional Research in Alzheimer's Genetic Epidemiology) Study, and from 168 AD cases, 336 individuals with mild cognitive impairment, and 188 controls in the Alzheimer's Disease Neuroimaging Initiative Study. A GWAS for each trait was conducted in the 2 Caucasian data sets in stage 1. Results from the 2 data sets were combined by meta-analysis. In stage 2, 1 single nucleotide polymorphism (SNP) from each region that was nominally significant in each data set (p < 0.05) and strongly associated in both data sets (p < 1.0 × 10(-5)) was evaluated in the African American data set.

RESULTS

Twenty-two markers (14 for HV, 3 for TCV, and 5 for WMH) from distinct regions met criteria for evaluation in stage 2. Novel genome-wide significant associations (p < 5.0 × 10(-8)) were attained for HV with SNPs in the APOE, F5/SELP, LHFP, and GCFC2 gene regions. All of these associations were supported by evidence in each data set. Associations with different SNPs in the same gene (p < 1 × 10(-5) in Caucasians and p < 2.2 × 10(-4) in African Americans) were also observed for PICALM with HV, SYNPR with TCV, and TTC27 with WMH.

INTERPRETATION

Our study demonstrates the efficacy of endophenotypes for broadening our understanding of the genetic basis of AD.

Novel late-onset Alzheimer disease loci variants associate with brain gene expression

OBJECTIVE

Recent genome-wide association studies (GWAS) of late-onset Alzheimer disease (LOAD) identified 9 novel risk loci. Discovery of functional variants within genes at these loci is required to confirm their role in Alzheimer disease (AD). Single nucleotide polymorphisms that influence gene expression (eSNPs) constitute an important class of functional variants. We therefore investigated the influence of the novel LOAD risk loci on human brain gene expression.

METHODS

We measured gene expression levels in the cerebellum and temporal cortex of autopsied AD subjects and those with other brain pathologies (∼400 total subjects). To determine whether any of the novel LOAD risk variants are eSNPs, we tested their cis-association with expression of 6 nearby LOAD candidate genes detectable in human brain (ABCA7, BIN1, CLU, MS4A4A, MS4A6A, PICALM) and an additional 13 genes ±100 kb of these SNPs. To identify additional eSNPs that influence brain gene expression levels of the novel candidate LOAD genes, we identified SNPs ±100 kb of their location and tested for cis-associations.

RESULTS

CLU rs11136000 (p = 7.81 × 10(-4)) and MS4A4A rs2304933/rs2304935 (p = 1.48 × 10(-4)-1.86 × 10(-4)) significantly influence temporal cortex expression levels of these genes. The LOAD-protective CLU and risky MS4A4A locus alleles associate with higher brain levels of these genes. There are other cis-variants that significantly influence brain expression of CLU and ABCA7 (p = 4.01 × 10(-5)-9.09 × 10(-9)), some of which also associate with AD risk (p = 2.64 × 10(-2)-6.25 × 10(-5)).

CONCLUSIONS

CLU and MS4A4A eSNPs may at least partly explain the LOAD risk association at these loci. CLU and ABCA7 may harbor additional strong eSNPs. These results have implications in the search for functional variants at the novel LOAD risk loci.

Influence of ROBO1 and RORA on risk of age-related macular degeneration reveals genetically distinct phenotypes in disease pathophysiology

ROBO1 is a strong candidate gene for age-related macular degeneration (AMD) based upon its location under a linkage peak on chromosome 3p12, its expression pattern, and its purported function in a pathway that includes RORA, a gene previously associated with risk for neovascular AMD. Previously, we observed that expression of ROBO1 and RORA is down-regulated among wet AMD cases, as compared to their unaffected siblings. Thus, we hypothesized that contribution of association signals in ROBO1, and interaction between these two genes may be important for both wet and dry AMD. We evaluated association of 19 single nucleotide polymorphisms (SNPs) in ROBO1 with wet and dry stages of AMD in a sibling cohort and a Greek case-control cohort containing 491 wet AMD cases, 174 dry AMD cases and 411 controls. Association signals and interaction results were replicated in an independent prospective cohort (1070 controls, 164 wet AMD cases, 293 dry AMD cases). The most significantly associated ROBO1 SNPs were rs1387665 under an additive model (meta P = 0.028) for wet AMD and rs9309833 under a recessive model (meta P = 6 × 10(-4)) for dry AMD. Further analyses revealed interaction between ROBO1 rs9309833 and RORA rs8034864 for both wet and dry AMD (interaction P<0.05). These studies were further supported by whole transcriptome expression profile studies from 66 human donor eyes and chromatin immunoprecipitation assays from mouse retinas. These findings suggest that distinct ROBO1 variants may influence the risk of wet and dry AMD, and the effects of ROBO1 on AMD risk may be modulated by RORA variants.

Common variants at MS4A4/MS4A6E, CD2AP, CD33 and EPHA1 are associated with late-onset Alzheimer's disease

The Alzheimer Disease Genetics Consortium (ADGC) performed a genome-wide association study of late-onset Alzheimer disease using a three-stage design consisting of a discovery stage (stage 1) and two replication stages (stages 2 and 3). Both joint analysis and meta-analysis approaches were used. We obtained genome-wide significant results at MS4A4A (rs4938933; stages 1 and 2, meta-analysis P (P(M)) = 1.7 × 10(-9), joint analysis P (P(J)) = 1.7 × 10(-9); stages 1, 2 and 3, P(M) = 8.2 × 10(-12)), CD2AP (rs9349407; stages 1, 2 and 3, P(M) = 8.6 × 10(-9)), EPHA1 (rs11767557; stages 1, 2 and 3, P(M) = 6.0 × 10(-10)) and CD33 (rs3865444; stages 1, 2 and 3, P(M) = 1.6 × 10(-9)). We also replicated previous associations at CR1 (rs6701713; P(M) = 4.6 × 10(-10), P(J) = 5.2 × 10(-11)), CLU (rs1532278; P(M) = 8.3 × 10(-8), P(J) = 1.9 × 10(-8)), BIN1 (rs7561528; P(M) = 4.0 × 10(-14), P(J) = 5.2 × 10(-14)) and PICALM (rs561655; P(M) = 7.0 × 10(-11), P(J) = 1.0 × 10(-10)), but not at EXOC3L2, to late-onset Alzheimer's disease susceptibility.

Meta-analysis confirms CR1, CLU, and PICALM as alzheimer disease risk loci and reveals interactions with APOE genotypes

OBJECTIVES

To determine whether genotypes at CLU, PICALM, and CR1 confer risk for Alzheimer disease (AD) and whether risk for AD associated with these genes is influenced by apolipoprotein E (APOE) genotypes.

DESIGN

Association study of AD and CLU, PICALM, CR1, and APOE genotypes.

SETTING

Academic research institutions in the United States, Canada, and Israel.

PARTICIPANTS

Seven thousand seventy cases with AD, 3055 with autopsies, and 8169 elderly cognitively normal controls, 1092 with autopsies, from 12 different studies, including white, African American, Israeli-Arab, and Caribbean Hispanic individuals.

RESULTS

Unadjusted, CLU (odds ratio [OR], 0.91; 95% confidence interval [CI], 0.85-0.96 for single-nucleotide polymorphism [SNP] rs11136000), CR1 (OR, 1.14; 95% CI, 1.07-1.22; SNP rs3818361), and PICALM (OR, 0.89; 95% CI, 0.84-0.94, SNP rs3851179) were associated with AD in white individuals. None were significantly associated with AD in the other ethnic groups. APOE ε4 was significantly associated with AD (ORs, 1.80-9.05) in all but 1 small white cohort and in the Arab cohort. Adjusting for age, sex, and the presence of at least 1 APOE ε4 allele greatly reduced evidence for association with PICALM but not CR1 or CLU. Models with the main SNP effect, presence or absence of APOE ε4, and an interaction term showed significant interaction between presence or absence of APOE ε4 and PICALM.

CONCLUSIONS

We confirm in a completely independent data set that CR1, CLU, and PICALM are AD susceptibility loci in European ancestry populations. Genotypes at PICALM confer risk predominantly in APOE ε4-positive subjects. Thus, APOE and PICALM synergistically interact.

Impact of saphenous vein graft radiographic markers on clinical events and angiographic parameters

BACKGROUND

Use of saphenous vein graft (SVG) radiographic markers has been associated with shorter cardiac catheterization procedure times and reduced contrast agent volume for postoperative coronary artery bypass graft (CABG) catheterizations. Use of such markers is varied and often operator-dependent, as the effect of SVG markers has not been fully evaluated. The goal of the present analysis was to evaluate the association of SVG markers with clinical outcomes and graft patency.

METHODS

Data were drawn from the Project of Ex-vivo Vein Graft Engineering via Transfection (PREVENT) IV trial of patients undergoing CABG at 107 hospitals across the United States. Repeat angiography was performed within 12 to 18 months after CABG. The SVG markers were used at the discretion of the surgeon and were identified on the follow-up angiogram as any device used to mark the ostium, regardless of shape.

RESULTS

The SVG markers were present in 51.2% of evaluable patients (910 of 1,778) and 52.3% of SVGs (2,228 of 4,240). Among patients with totally occluded SVGs (n = 911), visual identification of the SVG was obtained more frequently in those with an SVG marker (90.7% vs 72.1%, p < 0.001). The SVG stenosis 70% or greater at follow-up did not differ by use of markers (25.8% with marker vs 24.4% without marker, p = not significant). These findings were also consistent in ostial lesions (n = 942). Long-term death or myocardial infarction (MI) was similar by use of marker. The perioperative CABG MI was higher in patients with SVG markers (10.1% vs 5.5%, odds ratio adjusted 1.86, p = 0.021).

CONCLUSIONS

Saphenous vein graft radiographic markers were associated with higher rates of direct visualization of totally occluded SVGs without an adverse effect on graft patency or long-term clinical outcomes, but the association of SVG markers with increased perioperative CABG MI warrants further examination.

Impact of iodinated contrast injections on percent diameter coronary arterial stenosis and implications for trials of intracoronary pharmacotherapies in patients with ST-elevation myocardial infarction

Administration of fibrinolytic, antiplatelet, and antithrombotic agents by the intracoronary route may disaggregate clot, but the potential role of the mechanical force of the injection itself in decreasing clot burden has not been studied. Patients with ST-segment elevation myocardial infarction who were pretreated in the emergency room (ER) with unfractionated heparin and aspirin in the TITAN-TIMI 34 study were randomized to treatment with eptifibatide in the ER (n = 131) versus after diagnostic catheterization (n = 150). Quantitative coronary angiography was used to assess change in diameter stenosis from time of first contrast injection to injection before percutaneous coronary intervention (PCI) immediately preceding wire placement down the culprit artery in a matching view. Successful perfusion of the myocardium was assessed after PCI by the presence of Thrombolysis In Myocardial Infarction myocardial perfusion grade of 2 or 3. In patients treated with eptifibatide in the ER, there was a 1.3% absolute improvement in diameter stenosis from the first injection to the injection before PCI (p = 0.02), whereas there was no change in diameter stenosis in patients not treated with eptifibatide in the ER (0.0%, p = NS). Each 1% improvement in percent diameter stenosis during diagnostic injections before PCI was strongly correlated with an open muscle after PCI (adjusted odds ratio 1.09, 95% confidence interval 1.02 to 1.16, p = 0.012). In conclusion, the mechanical force of a contrast injection decreases thrombotic burden in patients with ST-segment elevation myocardial infarction pretreated with eptifibatide but not with placebo. Future trials of intracoronary pharmacotherapies should include a control arm in which saline is injected to account for the potential clot disaggregation that occurs as a result of iodinated contrast injections, particularly if the patient has been pretreated with aggressive pharmacotherapy.

Global outcomes of ST-elevation myocardial infarction: comparisons of the Enoxaparin and Thrombolysis Reperfusion for Acute Myocardial Infarction Treatment-Thrombolysis In Myocardial Infarction study 25 (ExTRACT-TIMI 25) registry and trial

BACKGROUND

Outcomes in patients with ST-elevation myocardial infarction (STEMI) differ between those in clinical trials and those in routine practice, as well as across different regions. We hypothesized that adjustment for baseline risk would minimize such variations.

METHODS

The Enoxaparin and Thrombolysis Reperfusion for Acute Myocardial Infarction Treatment-Thrombolysis In Myocardial Infarction (ExTRACT-TIMI) 25 registry was an observational study of patients with STEMI presenting to hospitals participating in the ExTRACT-TIMI 25 randomized clinical trial. Consecutive patients with STEMI who were not enrolled in the trial were entered into the registry. Demographics, in-hospital therapies, and in-hospital events were collected. Baseline risk was assessed using the TIMI Risk Index for STEMI. To adjust for differences among the countries from which the patients presented, the gross national income per annum per capita (GNI) was used.

RESULTS

A total of 3726 patients were registered from 109 sites in 25 countries. Patients in the registry had a higher baseline risk than those in the trial; they had more extensive prior cardiac histories and more comorbidities. Unadjusted in-hospital mortality was higher in the registry (8.3%) than in the trial (6.6%) (hazard ratio, 1.30; P < .001); however, after adjusting for TIMI Risk Index, mortality was similar (hazard ratio(adj), 1.00; P = .97). The GNI was not significantly predictive of in-hospital mortality in the multivariable model of the registry.

CONCLUSION

Patients in the registry had higher mortality than those in the trial. This difference could be explained by the higher baseline risk of patients in the registry. After adjusting for baseline risk, the GNI of the country in which the patient presented did not contribute to predicting in-hospital mortality.

Diagnostic and prognostic value of ambulatory ECG (Holter) monitoring in patients with coronary heart disease: a review

Silent ischemia, the most common expression of atherosclerotic heart disease, affects approximately 30-50% of patients during their activities of daily living. The present review provides a comprehensive and practical summary of current knowledge on perioperative myocardial ischemia through MEDLINE searches up to June 2005, using keywords including "silent ischemia," "transient ischemia," and "Holter monitoring." Holter monitoring (i.e., continuous ambulatory ST-segment monitoring) is an effective tool for assessing the frequency and duration of silent transient myocardial ischemia, particularly in patients who are post-acute myocardial infarction (MI), those with acute coronary syndromes (ACS), and in patients in the acute post-operative period. Holter monitoring allows for further risk stratification of patients who have a positive exercise ECG by collecting long-term ECG data on ischemic and arrhythmic events while patients perform routine activities. Both the presence and increased duration of transient ischemia as detected by continuous ST-segment Holter monitoring are associated with increased rates of coronary events and mortality. Holter monitoring may aid in the identification of patients and subgroups of patients with ACS who may derive the greatest benefit from antiplatelet and antithrombotic therapy. Indeed, many ongoing and upcoming trials of pharmacotherapy include ischemia on Holter monitoring as an endpoint.

Synergistic relationship between hyperglycaemia and inflammation with respect to clinical outcomes in non-ST-elevation acute coronary syndromes: analyses from OPUS-TIMI 16 and TACTICS-TIMI 18

AIMS

To investigate the relationship between diabetes and inflammation and the potentially synergistic relationship between hyperglycaemia and inflammation on clinical outcomes in non ST-elevation ACS.

METHODS AND RESULTS

The principal analysis was conducted in 2200 patients in OPUS-TIMI 16 with C-reactive protein data available and then validated in the invasive arm of TACTICS-TIMI 18 (n = 929). In addition, two further inflammatory markers [monocyte chemoattractant protein-1 (MCP-1) and von Willebrand factor (vWF)] were assessed in OPUS-TIMI 16. Diabetic patients had higher C-reactive protein and MCP-1 levels vs. non-diabetic patients in OPUS-TIMI 16 (9 vs. 7.8 mg/L, P = 0.002, and 190.6 vs. 170.8 pg/mL, P = 0.04, respectively), higher C-reactive protein levels in TACTICS-TIMI 18 (6.6 vs. 5.2 mg/L, P = 0.0005), and as expected higher glucose levels in both trials. Stratifying by the median C-reactive protein and diabetes in OPUS-TIMI 16, diabetic patients with C-reactive protein greater than or equal to the median were the highest risk group vs. non-diabetic patients with C-reactive protein less than the median (adjusted HR 1.63, 95% CI 1.20-2.23, P = 0.002). Directionally, similar findings were observed for MCP-1 and vWF in OPUS-TIMI 16 and for C-reactive protein in TACTICS-TIMI 18. After adjustment for diabetes, the risk associated with a 1 mmol/L increase in glucose was greater among those with a C-reactive protein greater than or equal to the median (HR 1.07, 95% CI 1.03-1.11) vs. those with a C-reactive protein less than the median (HR 1.02, 95% CI 0.97-1.06). After multivariable adjustment, the synergistic relationship between glucose and C-reactive protein and clinical outcomes remained statistically significant (P = 0.01). A similar pattern was observed in TACTICS-TIMI 18.

CONCLUSION

Among ACS patients, diabetes was associated with both greater inflammation and higher glucose levels and patients with both hyperglycaemia and inflammation had worse outcomes. Better control of both inflammation and hyperglycaemia should be assessed in future ACS trials as a means to reduce the cardiovascular risk among diabetics.

Hemodynamic significance of periprocedural myocardial injury assessed with N-terminal pro-B-type natriuretic peptide after percutaneous coronary intervention in patients with stable and unstable coronary artery disease (from the JUMBO-TIMI 26 trial)

The clinical relevance of periprocedural myocardial injury related to percutaneous coronary intervention (PCI) remains controversial. N-terminal pro-B-type natriuretic peptide (NT-pro-BNP) is a sensitive indicator of hemodynamic stress and when increased is associated with higher mortality in patients with acute and chronic ischemic heart disease. We measured the serum level of NT-pro-BNP using the Elecsys 2010 proBNP assay at baseline, 4 to 6 hours, and 12 to 24 hours in 747 patients undergoing elective or urgent PCI and enrolled in the JUMBO-TIMI 26 trial. Periprocedural myocardial infarction (MI) was independently adjudicated and required a new increase in creatine kinase-MB >3 times the upper limit of normal distinct from MI as the indication for PCI. Patients with procedural MI had significantly higher levels of NT-pro-BNP at 12 to 24 hours (405 vs 146 pg/ml, p <0.001). Moreover, the greater increase in NT-pro-BNP in patients with periprocedural MI was independent of each clinical and other procedural correlates of NT-pro-BNP after PCI (p <0.001). In addition, the magnitude of increase in NT-pro-BNP correlated strongly with extent of myocardial injury, including in patients with evidence of injury (creatine kinase-MB 1 to 3 times upper limit of normal) not meeting criteria for MI (p = 0.001) or low-level increase in troponin T (p = 0.001). In conclusion, periprocedural myocardial injury, even at low levels, during PCI is associated with increased hemodynamic stress as measured by increasing NT-pro-BNP. This finding supports the physiologic relevance of procedural MI and the continued effort to define therapies that decrease the risk of this complication.

Peripheral arterial disease, acute coronary syndromes, and early invasive management: the TACTICS TIMI 18 trial

BACKGROUND

Patients with peripheral arterial disease (PAD) represent a high-risk patient subset in the setting of non-ST-segment elevation acute coronary syndromes (NSTE ACS). The efficacy and safety of early invasive management for such patients remains unclear.

HYPOTHESIS

Early invasive management would be well tolerated and effective among patients with NSTE ACS and PAD.

METHODS

Patients from the Treat angina with Aggrastat and determine Cost of Therapy with an Invasive or Conservative Strategy-Thrombolysis In Myocardial Infarction (TACTICS-TIMI) 18 trial were stratified by the presence or absence of PAD and assessed with respect to baseline clinical factors. The outcomes of patients with PAD and NSTE ACS were examined with respect to treatment assignment to either early invasive therapy or conservative treatment of NSTE ACS. Finally, the bleeding and stroke rates of patients with PAD managed invasively were compared with patients with PAD managed conservatively.

RESULTS

Of 2219 patients with NSTE ACS overall, 166 (7.5%) had concomitant PAD. Compared with those patients without PAD, those with PAD were older (75 vs. 62 years, p < 0.001) and were more likely to have high-risk clinical features, including prior histories of bypass surgery (39 vs. 20%, p < 0.001) or diabetes mellitus (38 vs. 27%, p = 0.002), and more ST-segment depression on their 12-lead electrocardiogram (43 vs. 29%, p < 0.001). Among such patients, early invasive management was associated with significant reductions in the risk of myocardial infarction (MI) at 30 days (11.4 vs. 2.3%, p = 0.03). At 180 days, compared with early conservative management, early invasive treatment for patients with PAD and NSTE ACS was associated with similar reductions in MI (12.7 vs. 3.5%, p = 0.04), and was also accompanied by significant reductions in risk of death (10.1 vs. 2.3%, p = 0.05). No excess in bleeding or stroke rates was noted among patients with PAD managed invasively.

CONCLUSIONS

Among patients with NSTE ACS and a history of PAD, early invasive management is well tolerated and accompanied by significant reductions in morbidity and mortality when compared with a more conservative, ischemia-driven approach.