Impact of rural versus urban geographic location on length of stay after carotid endarterectomy

Abstract Background: Reducing the incidence of extended length of stay (ELOS) after carotid endarterectomy (CEA), defined as LOS \u3e I day, is an important quality improvement focus of the Vascular Quality Initiative (VQI). Rural patients with geographic barriers pose a particular challenge for discharge and may have higher incidences of ELOS as a result. The purpose of this study was to examine the impact of patients’ home geographic location on ELOS after CEA. Methods: The VQI national database for CEA comprised the sample for analyses (N = 66,900). Rural-Urban Commuting Area (RUCA) codes, a validated system used to classify the nation’s census tracts according to rural and urban status, was applied to the VQI database and used to indicate patients’ home geographic location. LOS was categorized into two groups: LOS ≤ 1 day (66%) and LOS \u3e 1 day (ELOS) (34%). Multivariable logistic regression was conducted to examine the effect of geographic location on ELOS after adjustment for age, gender, race, and comorbid conditions. Results: A total of 66,900 patients were analyzed and the mean age of the sample was 70.5 ± 9.3 years (40% female). After adjustment for covariates, the urban group had increased risk for ELOS (OR = 1.20, p \u3c 0.001). Other factors that significantly increased risk for ELOS were non-White race/Latinx/Hispanic ethnicity (OR = 1.44, p \u3c 0.001) and nonelective status (OR =3.31, p \u3c 0.001). In addition, patients treated at centers with a greater percentage of urban patients had greater risk for ELOS (OR = 1.008, p \u3c 0.001). Conclusions: These analyses found that geographic location did impact LOS, but not in the hypothesized direction. Even with adjustment for comorbidities and other factors, patients from urban areas and centers with more urban patients were more likely to have ELOS after CEA. These findings suggest that other mechanisms, such as racial disparities, barriers in access to care, and disparities in support after discharge for urban patients may have a significant impact on LOS

The Effect of Proprotein Convertase Subtilisin/Kexin Type 9 Inhibitors on Nonfasting Remnant Cholesterol in a Real World Population

Background. Proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors have demonstrated significant effects on low-density lipoprotein (LDL) cholesterol and nonhigh density lipoprotein (HDL) cholesterol. To date, there have been limited reports on the effect of PCSK9 inhibitors on remnant cholesterol. Objectives. Assess the effect of PCSK9 inhibitors on nonfasting remnant cholesterol in a real world population. Identify whether pretreatment triglyceride levels are associated with PCSK9 inhibition success as indicated by changes in remnant cholesterol levels. Methods. Patients in our adult lipid clinic (n = 109) receiving PCSK9 inhibition for atherosclerotic cardiovascular disease or familial hypercholesterolemia who had available pre- and post- PCSK9 inhibition standard nonfasting lipid data were, retrospectively, selected for data analysis. Remnant cholesterol was the difference between non-HDL and LDL cholesterol. LDL cholesterol was measured directly and calculated from Friedewald and Martin/Hopkins methods. Data were analyzed using repeated measures ANOVA and multivariable linear regression for differential effects on remnant and LDL cholesterol based upon pretreatment nonfasting triglyceride levels. Results. Remnant cholesterol as well as total, LDL, non-HDL cholesterol, and triglycerides decreased significantly (P\u3c0.001) after PCSK9 inhibition. Patients with higher pretreatment triglyceride levels showed greater decrease in remnant cholesterol after PCSK9 inhibition (P\u3c0.001) than those with lower pretreatment triglycerides. Conclusions. In patients receiving PCSK9 inhibitors, remnant cholesterol as determined from nonfasting blood was reduced in proportion to pretreatment triglycerides

The effect of the Cox-maze procedure for atrial fibrillation concomitant to mitral and tricuspid valve surgery

ObjectivesAtrial fibrillation (AF) is associated with less favorable outcomes in patients undergoing mitral valve and tricuspid valve surgery. Despite growing evidence on the potential benefits of surgical ablation for AF there is significant variability among surgeons in treatment of AF. The purpose of our study was to assess the effect of the Cox-maze procedure on operative and follow-up outcomes.MethodsIn our prospective study, patients who underwent isolated mitral valve or mitral valve+tricuspid valve surgery without history of AF (n = 506), with untreated AF (n = 75), or with Cox-maze procedure (n = 236) were included (N = 817). Sinus rhythm was captured according to Heart Rhythm Society guidelines. Patients who underwent the Cox-maze procedure were propensity score matched to patients without history of AF resulting in 208 pairs of patients.ResultsOperative outcomes were comparable after propensity score matching (Cox-maze procedure vs no AF) stroke/transient ischemic attack (0.5% vs 0.5%; P = 1.00), renal failure (2.9% vs 1.4%; P = .34), and operative mortality (1.4% vs 1.4%; P = 1.00). High return to sinus rhythm was documented at 6, 12, and 24 months (92%, 91%, and 86%, respectively) as well as sinus rhythm off antiarrhythmic drugs (79%, 84%, and 82%, respectively). Incidence of embolic stroke in patients who underwent Cox-maze procedure was 1.7% (4 out of 232 patients) and 5.1 cases per 1000 person-years. No difference in 4-year cumulative survival between propensity score-matched groups (91.9% vs 86.9%; log rank, 1.67; P = .20), but higher for patients who underwent Cox-maze procedure versus patients with untreated AF (hazard ratio, 2.47; P = .048). Higher additive European System for Cardiac Operative Risk Evaluation (odds ratio, 1.40; P < .001) and limited surgeon experience with Cox-maze procedure (odds ratio, 3.60; P < .001) were significant predictors for failure to perform Cox-maze procedure.ConclusionsIn our center, 76% of patients undergoing mitral valve or mitral valve+tricuspid valve surgery experiencing AF underwent concomitant Cox-maze procedure, which is considerably higher than the national average. No increased morbidity was associated with the Cox-maze procedure with the benefit of very low thromboembolic rate. These results suggest the need for performance-based education for AF surgical ablation to achieve optimal outcomes

Robust simplifications of multiscale biochemical networks

<p>Abstract</p> <p>Background</p> <p>Cellular processes such as metabolism, decision making in development and differentiation, signalling, etc., can be modeled as large networks of biochemical reactions. In order to understand the functioning of these systems, there is a strong need for general model reduction techniques allowing to simplify models without loosing their main properties. In systems biology we also need to compare models or to couple them as parts of larger models. In these situations reduction to a common level of complexity is needed.</p> <p>Results</p> <p>We propose a systematic treatment of model reduction of multiscale biochemical networks. First, we consider linear kinetic models, which appear as "pseudo-monomolecular" subsystems of multiscale nonlinear reaction networks. For such linear models, we propose a reduction algorithm which is based on a generalized theory of the limiting step that we have developed in <abbrgrp><abbr bid="B1">1</abbr></abbrgrp>. Second, for non-linear systems we develop an algorithm based on dominant solutions of quasi-stationarity equations. For oscillating systems, quasi-stationarity and averaging are combined to eliminate time scales much faster and much slower than the period of the oscillations. In all cases, we obtain robust simplifications and also identify the critical parameters of the model. The methods are demonstrated for simple examples and for a more complex model of NF-<it>κ</it>B pathway.</p> <p>Conclusion</p> <p>Our approach allows critical parameter identification and produces hierarchies of models. Hierarchical modeling is important in "middle-out" approaches when there is need to zoom in and out several levels of complexity. Critical parameter identification is an important issue in systems biology with potential applications to biological control and therapeutics. Our approach also deals naturally with the presence of multiple time scales, which is a general property of systems biology models.</p

Early Stable Sinus Rhythm Associated With Greater Success 5 Years After Surgical Ablation

Background—An important challenge in surgical ablation for atrial fibrillation (AF) is the scarcity of publications on credible predictors of long-term success in procedures performed with ablation tools that produce consistently reliable transmural lesions. We examined factors associated with 1-year success and no atrial arrhythmia (AA) recurrence during 1 to 5 years after surgical ablation for AF. Methods—The study prospectively monitored 743 surgical ablation patients with complete rhythm follow-up at 12 months after the operation. No detected AA was defined as no known recurrence of AA, no cardioversions, and no catheter ablations at all available follow-up assessments. Results—Patients were a mean age of 64.7 years, and 32% were women. Patients with no detected AA during the first year after surgical ablation were more likely to maintain sinus rhythm without recurrence during 1 to 5 years (74% vs 28%, p \u3c 0.001) and to be in sinus rhythm off medication at 5 years (80% vs 53%, p \u3c 0.001). Mixed-model logistic regression revealed that lower risk for AA recurrence during 1 to 5 years was associated with no detected AA during the first 12 months (odds ratio [OR], 0.11; p \u3c 0.001) and surgeon experience with 50 or more cases (OR, 0.63; p = 0.043), whereas older age (OR, 1.03; p \u3c 0.001) and longer preoperative AF duration (OR, 1.04; p = 0.043) were associated with greater risk for AA recurrence. Conclusions—Most patients with no detected AA throughout the first 12 months after surgical ablation continued to be recurrence free for 5 years. Younger age, shorter preoperative AF duration, and greater surgeon experience may be associated with more persistent surgical correction of AF

The Effect of Proprotein Convertase Subtilisin/Kexin Type 9 Inhibitors on Nonfasting Remnant Cholesterol in a Real World Population

Background. Proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors have demonstrated significant effects on low-density lipoprotein (LDL) cholesterol and nonhigh density lipoprotein (HDL) cholesterol. To date, there have been limited reports on the effect of PCSK9 inhibitors on remnant cholesterol. Objectives. Assess the effect of PCSK9 inhibitors on nonfasting remnant cholesterol in a real world population. Identify whether pretreatment triglyceride levels are associated with PCSK9 inhibition success as indicated by changes in remnant cholesterol levels. Methods. Patients in our adult lipid clinic (n = 109) receiving PCSK9 inhibition for atherosclerotic cardiovascular disease or familial hypercholesterolemia who had available pre- and post-PCSK9 inhibition standard nonfasting lipid data were, retrospectively, selected for data analysis. Remnant cholesterol was the difference between non-HDL and LDL cholesterol. LDL cholesterol was measured directly and calculated from Friedewald and Martin/Hopkins methods. Data were analyzed using repeated measures ANOVA and multivariable linear regression for differential effects on remnant and LDL cholesterol based upon pretreatment nonfasting triglyceride levels. Results. Remnant cholesterol as well as total, LDL, non-HDL cholesterol, and triglycerides decreased significantly (P<0.001) after PCSK9 inhibition. Patients with higher pretreatment triglyceride levels showed greater decrease in remnant cholesterol after PCSK9 inhibition (P<0.001) than those with lower pretreatment triglycerides. Conclusions. In patients receiving PCSK9 inhibitors, remnant cholesterol as determined from nonfasting blood was reduced in proportion to pretreatment triglycerides

Long-term outcome following concomitant mitral valve surgery and Cox maze procedure for atrial fibrillation

Objective—Atrial fibrillation (AF) is associated with increased early and long-term morbidity/ mortality following valve surgery. This study examined long-term influence of concomitant full Cox maze (CM) and mitral valve procedures on freedom from atrial arrhythmia and stroke. Methods—This sample comprised patients who underwent CM with a mitral valve procedure (N = 473). Data on rhythm, medication status, and clinical events captured according to Heart Rhythm Society guidelines at 6, 9, 12, 18, and 24 months and yearly thereafter up to 7 years. Results—Mean age was 65 years, mean left atrium size was 5.3 cm, and 15% had paroxysmal AF. Perioperative stroke occurred in 2 patients (0.4%) and operative mortality was 2.7% (n = 13). Return to sinus rhythm regardless of antiarrhythmic drugs at 1, 5, and 7 years was 90%, 80%, and 66%. Sinus rhythm off antiarrhythmic drugs at 1, 5, and 7 years was 83%, 69%, and 55%. Freedom from embolic stroke at 7 years was 96.6% (0.4 strokes per 100 patient-years) with a majority of patients off anticoagulation medication. Greater odds of atrial arrhythmia recurrence during 7 years was associated with longer AF duration (odds ratio [OR], 1.07; P = .001), whereas lower odds were associated with cryothermal energy only (OR, 0.64; P = .045) and greater surgeon experience (OR, 0.98; P = .025). Conclusions—This study suggests that the addition of CM to mitral valve procedures, even with a high degree of complexity, did not increase operative risk. In long-term follow-up, the CM procedure demonstrated acceptable rhythm success, reduced AF burden, and remarkably low stroke rate. Individual surgeon experience and training may notably influence long-term surgical ablation for AF success