Zgli: A Pipeline for Clustering by Compression with Application to Patient Stratification in Spondyloarthritis.

The normalized compression distance (NCD) is a similarity measure between a pair of finite objects based on compression. Clustering methods usually use distances (e.g., Euclidean distance, Manhattan distance) to measure the similarity between objects. The NCD is yet another distance with particular characteristics that can be used to build the starting distance matrix for methods such as hierarchical clustering or K-medoids. In this work, we propose Zgli, a novel Python module that enables the user to compute the NCD between files inside a given folder. Inspired by the CompLearn Linux command line tool, this module iterates on it by providing new text file compressors, a new compression-by-column option for tabular data, such as CSV files, and an encoder for small files made up of categorical data. Our results demonstrate that compression by column can yield better results than previous methods in the literature when clustering tabular data. Additionally, the categorical encoder shows that it can augment categorical data, allowing the use of the NCD for new data types. One of the advantages is that using this new feature does not require knowledge or context of the data. Furthermore, the fact that the new proposed module is written in Python, one of the most popular programming languages for machine learning, potentiates its use by developers to tackle problems with a new approach based on compression. This pipeline was tested in clinical data and proved a promising computational strategy by providing patient stratification via clusters aiding in precision medicine.

Long-term prognostic value of late gadolinium enhancement and periprocedural myocardial infarction after uncomplicated revascularization: MASS-V follow-up.

AIMS: Cardiac biomarkers elevation is common after revascularization, even in absence of periprocedural myocardial infarction (PMI) detection by imaging methods. Thus, late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) may be useful on PMI diagnosis and prognosis. We sought to evaluate long-term prognostic value of PMI and new LGE after revascularization. METHODS AND RESULTS: Two hundred and two patients with multivessel coronary disease and preserved ventricular function who underwent elective revascularization were included, of whom 136 (67.3%) underwent coronary artery bypass grafting and 66 (32.7%) percutaneous coronary intervention. The median follow-up was 5 years (4.8-5.8 years). Cardiac biomarkers measurement and LGE-CMR were performed before and after procedures. The Society for Cardiovascular Angiography and Interventions definition was used to assess PMI. Primary endpoint was composed of death, infarction, additional revascularization, or cardiac hospitalization. Primary endpoint was observed in 29 (14.3%) patients, of whom 13 (14.9%) had PMI and 16 (13.9%) did not (P = 0.93). Thirty-six (17.8%) patients had new LGE. Twenty (12.0%) events occurred in patients without new LGE and 9 (25.2%) in patients with it (P = 0.045). LGE was also associated to increased mortality, with 4 (2.4%) and 4 (11.1%) deaths in subjects without and with it (P = 0.02). LGE was the only independent predictor of primary endpoint and mortality (P = 0.03 and P = 0.02). Median LGE mass was estimated at 4.6 g. Patients with new LGE had a greater biomarkers release (median troponin: 8.9 ng/mL vs. 1.8 ng/mL and median creatine kinase-MB: 38.0 ng/mL vs. 12.3 ng/mL; P < 0.001 in both comparisons). CONCLUSIONS: New LGE was shown to be better prognostic predictor than biomarker-only PMI definition after uncomplicated revascularization. Furthermore, new LGE was the only independent predictor of cardiovascular events and mortality. CLINICAL TRIAL REGISTRATION: http://www.controlled-trials.com/ISRCTN09454308.

Significant association of SYNTAX score on release of cardiac biomarkers in uncomplicated post-revascularization procedures among patients with stable multivessel disease: MASS-V Study group.

This study investigated the relationship between angiographic complexities of coronary artery disease (CAD) assessed by SYNTAX Score synergy between percutaneous coronary intervention with taxus and cardiac surgery score (SYNTAX Score) and cardiac biomarker elevation after revascularization procedures.This is a post-hoc analysis of the medicine, angioplasty or surgery study V study of patients with stable CAD. High-sensitivity troponin 1 (hs-TnI) and creatinine kinase-muscle/brain (CK-MB) were assessed before and after cardiovascular procedures. Baselines SYNTAX Scores (SXScores) were calculated by blinded investigators to patient characteristics.Of the 202 patients studied, the mean SXScore was 21.25 ±â€Š9.24; 40.10 ±â€Š7.09 in the high SXScore group and 19.06 ±â€Š6.61 in low/mid SXscore group (P < .0001). Positive correlations existed between SXScore and median peaks after procedural hs-TnI (r = 0.18, P = .009) and CK-MB (r = 0.24, P = .001) levels. In patients with high SXScores (≥33), the median peaks of post-procedural hs-TnI (P = .034)and CK-MB (P = .004) levels were higher than in low/mid SXScore group (<33).The release of hs-TnI at 6 (P = .002), 12 (P = .008), and 24 hours (P = .039) was higher in high SXScore group than in low/mid SXscore group (<33) as was the release of CK-MB at 6 (P < .0001), 12 (P < .0001), 24 (P = .001), 36 (P = .007), 48 (P = .008), and 72 hours (P = .023). After multivariable analysis, high SXScore was a significant independent predictor of release of CK-MB and hs-TnI peaks higher than the median.The increase in release of cardiac biomarkers was significantly associated with the extent of atherosclerosis identified by the SYNTAX Score.

Long-term outcomes of patients with stable coronary disease and chronic kidney dysfunction: 10-year follow-up of the Medicine, Angioplasty, or Surgery Study II Trial.

BACKGROUND: Chronic kidney disease (CKD) is associated with a worse prognosis in patients with stable coronary artery disease (CAD); however, there is limited randomized data on long-term outcomes of CAD therapies in these patients. We evaluated long-term outcomes of CKD patients with CAD who underwent randomized therapy with medical treatment (MT) alone, percutaneous coronary intervention (PCI) or coronary artery bypass graft surgery (CABG). METHODS: Baseline estimated glomerular filtration rate (eGFR) was obtained in 611 patients randomized to one of three therapeutic strategies in the Medicine, Angioplasty, or Surgery Study II trial. Patients were categorized in preserved renal function and mild or moderate CKD groups depending on their eGFR (≥90, 89-60 and 59-30 mL/min/1.73 m2, respectively). The primary clinical endpoint, a composite of overall death and myocardial infarction, and its individual components were analyzed using proportional hazards regression (Clinical Trial registration information: http://www.controlled-trials.com. Registration number: ISRCTN66068876). RESULTS: Of 611 patients, 112 (18%) had preserved eGFR, 349 (57%) mild dysfunction and 150 (25%) moderate dysfunction. The primary endpoint occurred in 29.5, 32.4 and 44.7% (P = 0.02) for preserved eGFR, mild CKD and moderate CKD, respectively. Overall mortality incidence was 18.7, 23.8 and 39.3% for preserved eGFR, mild CKD and moderate CKD, respectively (P = 0.001). For preserved eGFR, there was no significant difference in outcomes between therapies. For mild CKD, the primary event rate was 29.4% for PCI, 29.1% for CABG and 41.1% for MT (P = 0.006) [adjusted hazard ratio (HR) = 0.26, 95% confidence interval (CI) 0.07-0.88; P = 0.03 for PCI versus MT; and adjusted HR = 0.48; 95% CI 0.31-0.76; P = 0.002 for CABG versus MT]. We also observed higher mortality rates in the MT group (28.6%) compared with PCI (24.1%) and CABG (19.0%) groups (P = 0.015) among mild CKD subjects (adjusted HR = 0.44, 95% CI 0.25-0.76; P = 0.003 for CABG versus MT; adjusted HR = 0.56, 95% CI 0.07-4.28; P = 0.58 for PCI versus MT). Results were similar with moderate CKD group but did not achieve significance. CONCLUSIONS: Coronary interventional therapy, both PCI and CABG, is associated with lower rates of events compared with MT in mild CKD patients >10 years of follow-up. More study is needed to confirm these benefits in moderate CKD.

Chagas disease is associated with a worse prognosis at 1-year follow-up after implantable cardioverter-defibrillator for secondary prevention in heart failure patients.

INTRODUCTION: There are conflicting data regarding the efficacy of implantable cardioverter-defibrillator (ICD) in Chagas disease (CD) patients. This study aims to evaluate the short-term outcome after ICD for secondary prevention, in a population where CD is a prevalent cause of heart failure (HF). METHODS AND RESULTS: Consecutive patients with HF and reduced left ventricular ejection fraction (LVEF), who underwent ICD implantation for secondary prevention of SCD. Clinical and demographic data were collected to investigate mortality predictors at 1 year. During the study period, 117 patients underwent ICD implantation, of which 108 were included. The most frequent causes of HF was CD: 52 (48.1%) and ischemic cardiomyopathy: 20 (18.5%). Chagas and non-Chagas patients were well balanced-male: 32 (61.5%) vs 38 (67.9%), P = .548; age: 59.2 (±10.9) vs 56.8 (±13.4), P = .681; and LVEF: 34.1 (±0.2) vs 31.3 (±8.7), P = .064, respectively. At the mean follow-up of 15.7 months, overall mortality occurred in 14 (12.9%) patients, with a higher incidence in patients with CD cardiomyopathy, 11 (21.2%) vs 3 (5.4%), P = .021 (log-rank). In the multivariate analysis, CD remained as an independent predictor for death (hazard ratio: 4.62, confidence interval [95% CI]: 1.27-16.81, P = .021). CONCLUSION: CD was associated with a poor short-term outcome in patients with HF submitted to ICD implantation for secondary prevention when compared with other HF etiologies. In this specific HF population, ICD indication should be individualized, considering the worst prognosis of these patients.

Critical analysis of the classic indications for myocardial revascularization.

Treatment of stable coronary artery disease (CAD) relies on improved prognosis and relief of symptoms. National and international guidelines on CAD support the indication of revascularization in patients with limiting symptoms and refractory to optimal medical treatment, as well as in clinical situations where there is a prognostic benefit of interventional treatment. Most of the studies that support the guidelines for indication of revascularization date back to the 1980s and1990s of the last century. Recent studies have revisited the theme and brought a new breath. The present review provides a critical analysis of classic indications for revascularization, reviewing evidence from the studies of the 1970s to the recent controversial ORBITA study.

Critical analysis of the classic indications for myocardial revascularization

SUMMARY Treatment of stable coronary artery disease (CAD) relies on improved prognosis and relief of symptoms. National and international guidelines on CAD support the indication of revascularization in patients with limiting symptoms and refractory to optimal medical treatment, as well as in clinical situations where there is a prognostic benefit of interventional treatment. Most of the studies that support the guidelines for indication of revascularization date back to the 1980s and1990s of the last century. Recent studies have revisited the theme and brought a new breath. The present review provides a critical analysis of classic indications for revascularization, reviewing evidence from the studies of the 1970s to the recent controversial ORBITA study.

RESUMO O tratamento da doença arterial coronariana estável (DAC) se baseia na melhora do prognóstico e alívio de sintomas. Diretrizes nacionais e internacionais sobre a DAC respaldam a indicação de revascularização em pacientes com sintomas limitantes e refratários ao tratamento medicamentoso, bem como em situações clínicas nas quais há benefício prognóstico do tratamento intervencionista. Grande parte dos estudos que norteiam as diretrizes de indicação de revascularização data das décadas de 1980 e 1990. Estudos recentes têm revisitado o tema e trazido novo fôlego. A presente revisão faz uma análise crítica das indicações clássicas de revascularização, revisando a evidência desde os estudos da década de 1970 ao recente e polêmico estudo Orbita.

The ORBITA trial: A point of view.

Treatment of stable coronary artery disease (CAD) relies on improved prognosis and relief of symptoms. National and international guidelines on CAD support the indication for revascularization in patients with limiting symptoms and refractory to drug treatment. Previous studies attested the efficacy of angioplasty to improve angina as well as the functional capacity of patients with symptomatic stable CAD. The ORBITA trial, recently published in an international journal, showed no benefit in terms of exercise tolerance compared to a placebo procedure in a population of single-vessel patients undergoing contemporary percutaneous coronary intervention. In this point of view article, the authors discuss the ORBITA trial regarding methodological issues, limitations and clinical applicability.

Myocardial injury in diabetic patients with multivessel coronary artery disease after revascularization interventions.

BACKGROUND: Diabetic patients may be more susceptible to myocardial injury after coronary interventions. Thus, the aim of this study was to assess the release of cardiac biomarkers, CK-MB and troponin, and the findings of new late gadolinium enhancement (LGE) on cardiac magnetic resonance (CMR) in patients with type 2 diabetes mellitus after elective revascularization procedures for multivessel coronary artery disease (CAD). METHODS: Patients with multivessel CAD and preserved systolic ventricular function underwent either elective percutaneous coronary intervention (PCI), off-pump or on-pump bypass surgery (CABG). Troponin and CK-MB were systematically collected at baseline, 6, 12, 24, 36, 48 and 72 h after the procedures. CMR with LGE was performed before and after the interventions. Patients were stratified according to diabetes status at study entry. Biomarkers and CMR results were compared between diabetic and nondiabetics patients. Analyses of correlation were also performed among glycemic and glycated hemoglobin (A1c) levels and troponin and CK-MB peak levels. Patients were also stratified into tertiles of fasting glycemia and A1c levels and were compared in terms of periprocedural myocardial infarction (PMI) on CMR. RESULTS: Ninety (44.5%) of the 202 patients had diabetes mellitus at study entry. After interventions, median peak troponin was 2.18 (0.47, 5.14) and 2.24 (0.69, 5.42) ng/mL (P = 0.81), and median peak CK-MB was 14.1 (6.8, 31.7) and 14.0 (4.2, 29.8) ng/mL (P = 0.43), in diabetic and nondiabetic patients, respectively. The release of troponin and CK-MB over time was statistically similar in both groups and in the three treatments, besides PCI. New LGE on CMR indicated that new myocardial fibrosis was present in 18.9 and 17.3% (P = 0.91), and myocardial edema in 15.5 and 22.9% (P = 0.39) in diabetic and nondiabetic patients, respectively. The incidence of PMI in the glycemia tertiles was 17.9% versus 19.3% versus 18.7% (P = 0.98), and in the A1c tertiles was 19.1% versus 13.3% versus 22.2% (P = 0.88). CONCLUSIONS: In this study, diabetes mellitus did not add risk of myocardial injury after revascularization interventions in patients with multivessel coronary artery disease. Trial Registration Name of Registry: Evaluation of cardiac biomarker elevation after percutaneous coronary intervention or coronary artery bypass graft; URL: http://www.controlled-trials.com.ISRCTN09454308.

Oxygen delivery-utilization mismatch in contracting locomotor muscle in COPD: peripheral factors.

Central cardiorespiratory and gas exchange limitations imposed by chronic obstructive pulmonary disease (COPD) impair ambulatory skeletal muscle oxygenation during whole body exercise. This investigation tested the hypothesis that peripheral factors per se contribute to impaired contracting lower limb muscle oxygenation in COPD patients. Submaximal neuromuscular electrical stimulation (NMES; 30, 40, and 50 mA at 50 Hz) of the quadriceps femoris was employed to evaluate contracting skeletal muscle oxygenation while minimizing the influence of COPD-related central cardiorespiratory constraints. Fractional O2 extraction was estimated by near-infrared spectroscopy (deoxyhemoglobin/myoglobin concentration; deoxy-[Hb/Mb]), and torque output was measured by isokinetic dynamometry in 15 nonhypoxemic patients with moderate-to-severe COPD (SpO2 = 94 ± 2%; FEV1 = 46.4 ± 10.1%; GOLD II and III) and in 10 age- and gender-matched sedentary controls. COPD patients had lower leg muscle mass than controls (LMM = 8.0 ± 0.7 kg vs. 8.9 ± 1.0 kg, respectively; P < 0.05) and produced relatively lower absolute and LMM-normalized torque across the range of NMES intensities (P < 0.05 for all). Despite producing less torque, COPD patients had similar deoxy-[Hb/Mb] amplitudes at 30 and 40 mA (P > 0.05 for both) and higher deoxy-[Hb/Mb] amplitude at 50 mA (P < 0.05). Further analysis indicated that COPD patients required greater fractional O2 extraction to produce torque (i.e., ↑Δdeoxy-[Hb/Mb]/torque) relative to controls (P < 0.05 for 40 and 50 mA) and as a function of NMES intensity (P < 0.05 for all). The present data obtained during submaximal NMES of small muscle mass indicate that peripheral abnormalities contribute mechanistically to impaired contracting skeletal muscle oxygenation in nonhypoxemic, moderate-to-severe COPD patients.