Epidemic processes in complex networks

In recent years the research community has accumulated overwhelming evidence for the emergence of complex and heterogeneous connectivity patterns in a wide range of biological and sociotechnical systems. The complex properties of real-world networks have a profound impact on the behavior of equilibrium and nonequilibrium phenomena occurring in various systems, and the study of epidemic spreading is central to our understanding of the unfolding of dynamical processes in complex networks. The theoretical analysis of epidemic spreading in heterogeneous networks requires the development of novel analytical frameworks, and it has produced results of conceptual and practical relevance. A coherent and comprehensive review of the vast research activity concerning epidemic processes is presented, detailing the successful theoretical approaches as well as making their limits and assumptions clear. Physicists, mathematicians, epidemiologists, computer, and social scientists share a common interest in studying epidemic spreading and rely on similar models for the description of the diffusion of pathogens, knowledge, and innovation. For this reason, while focusing on the main results and the paradigmatic models in infectious disease modeling, the major results concerning generalized social contagion processes are also presented. Finally, the research activity at the forefront in the study of epidemic spreading in coevolving, coupled, and time-varying networks is reported.Comment: 62 pages, 15 figures, final versio

Outcome predictors for maternal red blood cell alloimmunisation with anti-K and anti-D managed with intrauterine blood transfusion

Red blood cell (RBC) alloimmunisation with anti-D and anti-K comprise the majority of cases of fetal haemolytic disease requiring intrauterine red cell transfusion (IUT). Few studies have investigated which haematological parameters can predict adverse fetal or neonatal outcomes. The aim of the present study was to identify predictors of adverse outcome, including preterm birth, intrauterine fetal demise (IUFD), neonatal death (NND) and/or neonatal transfusion. We reviewed the records of all pregnancies alloimmunised with anti-K and anti-D, requiring IUT over 27 years at a quaternary fetal centre. We reviewed data for 128 pregnancies in 116 women undergoing 425 IUTs. The median gestational age (GA) at first IUT was significantly earlier for anti-K than for anti-D (24·3 vs. 28·7 weeks, P = 0·004). Women with anti-K required more IUTs than women with anti-D (3·84 vs. 3·12 mean IUTs, P = 0·036) and the fetal haemoglobin (Hb) at first IUT was significantly lower (51.0 vs. 70.5 g/l, P = 0·001). The mean estimated daily decrease in Hb did not differ between the two groups. A greater number of IUTs and a slower daily decrease in Hb (g/l/day) between first and second IUTs were predictive of a longer period in utero. Earlier GA at first IUT and a shorter interval from the first IUT until delivery predicted IUFD/NND. Earlier GA and lower Hb at first IUT significantly predicted need for phototherapy and/or blood product use in the neonate. In the anti-K group, a greater number of IUTs was required in women with a higher titre. Furthermore, the higher the titre, the earlier the GA at which an IUT was required in both groups. The rate of fall in fetal Hb between IUTs decreased, as the number of transfusions increased. Our present study identified pregnancies at considerable risk of an unfavourable outcome with anti-D and anti-K RBC alloimmunisation. Identifying such patients can guide pregnancy management, facilitates patient counselling, and can optimise resource use. Prospective studies can also incorporate these characteristics, in addition to laboratory markers, to further identify and improve the outcomes of these pregnancies

Insights in a restricted temporary pacemaker strategy in a lean transcatheter aortic valve implantation program

OBJECTIVES: To study the safety and feasibility of a restrictive temporary‐RV‐pacemaker use and to evaluate the need for temporary pacemaker insertion for failed left ventricular (LV) pacing ability (no ventricular capture) or occurrence of high‐degree AV‐blocks mandating continuous pacing. BACKGROUND: Ventricular pacing remains an essential part of contemporary transcatheter aortic valve implantation (TAVI). A temporary‐right‐ventricle (RV)‐pacemaker lead is the standard approach for transient pacing during TAVI but requires central venous access. METHODS: An observational registry including 672 patients who underwent TAVI between June 2018 and December 2020. Patients received pacing on the wire when necessary, unless there was a high‐anticipated risk for conduction disturbances post‐TAVI, based on the baseline‐ECG. The follow‐up period was 30 days. RESULTS: A temporary‐RV‐pacemaker lead (RVP‐cohort) was inserted in 45 patients, pacing on the wire (LVP‐cohort) in 488 patients, and no pacing (NoP‐cohort) in 139 patients. A bailout temporary pacemaker was implanted in 14 patients (10.1%) in the NoP‐cohort and in 24 patients (4.9%) in the LVP‐cohort. One patient in the LVP‐cohort needed an RV‐pacemaker for incomplete ventricular capture. Procedure time was significantly longer in the RVP‐cohort (68 min [IQR 52–88.] vs. 55 min [IQR 44–72] in NoP‐cohort and 55 min [IQR 43–71] in the LVP‐cohort [p < 0.005]). Procedural high‐degree AV‐block occurred most often in the RVP‐cohort (45% vs. 14% in the LVP and 16% in the NoP‐cohort [p ≤ 0.001]). Need for new PPI occurred in 47% in the RVP‐cohort, versus 20% in the NoP‐cohort and 11% in the LVP‐cohort (p ≤ 0.001). CONCLUSION: A restricted RV‐pacemaker strategy is safe and shortens procedure time. The majority of TAVI‐procedures do not require a temporary‐RV‐pacemaker

Case report: Concomitant MitraClip implantation for severe mitral regurgitation and plug closure of endocarditis induced fistula between aortic root and left atrium after transcatheter aortic valve implantation

Background: Infective endocarditis (IE) after transcatheter aortic valve implantation (TAVI) occurs in up to 1.5% of patients within the first year. The development of an aorto-atrial fistula (AAF) is a rare but problematic complication of IE, which can be confirmed with transoesophageal echocardiography (TOE). We present an exceptional case of occluding an aorto-left atrial fistula only diagnosed with intraprocedural TOE during a subsequent procedure of MitraClip implantation. Case summary: A 79-year-old symptomatic male patient with multiple comorbidities was referred due to severe mitral regurgitation (MR). He has had prior TAVI which was complicated with streptococcal IE for which he had received prolonged antibacterial therapy. Transthoracic echocardiography (TTE) revealed severe MR. The patient was accepted for a MitraClip procedure by the heart team. Intra-procedural TOE revealed also a significant continuous shunt through an AAF which was likely caused by the endocarditis. The strategy was therefore defined as to occlude the fistula with an Amplatzer Vascular Plug II 12 mm. The plug was released in the fistula leaving an insignificant residual shunt. After the transseptal puncture one MitraClip XTR was implanted, reducing the MR to mild. After the procedure, the patient's general clinical condition improved without signs of haemolysis. The pre-discharge TTE confirmed trace residual shunt, mild residual MR and mild paravalvular leakage. Discussion: Our case illustrates a complex transcatheter structural heart intervention with improvised procedural strategies based on the intra-procedural TOE findings. We conclude that the pre-procedural TOE needs to be comprehensive rather than exclusive, particularly in the context of bioprosthesis-related endocarditis

Clinical consequences of consecutive self-expanding transcatheter heart valve iterations

OBJECTIVE: To compare early clinical outcomes after transcatheter aortic valve implantation (TAVI) with three consecutive generations of self-expanding valves (SEVs). METHODS: Clinical endpoints of consecutive patients who underwent TAVI with CoreValve, Evolut R or Evolut PRO were included in a prospective database. RESULTS: TAVI was performed with CoreValve (n = 116), Evolut R (n = 160) or Evolut PRO (n = 92). Evolut R and Evolut PRO showed a tendency towards lower permanent pacemaker implantation (PPI) rates compared to CoreValve (CoreValve 27% vs Evolut R 16% vs Evolut PRO 18%, p = 0.091). By multivariable regression analysis CoreValve had a significantly higher risk for PPI (odds ratio (OR) 2.79, 95% confidence interval (CI) 1.31–5.94, p = 0.008) compared to Evolut R, while Evolut R and PRO were similar. Severe paravalvular leakage (PVL) occurred only with CoreValve, but no significant difference was observed in moderate PVL (10% vs 8% vs 6%, p = 0.49). CoreValve had a tendency towards a higher risk for more-than-mild PVL as compared with the Evolut platform (R + PRO) (OR 2.46, 95% CI 0.98–6.16, p = 0.055). No significant differences in all-cause mortality (7% vs 4% vs 1%, p = 0.10), stroke (6% vs 3% vs 2%, p = 0.21) or major vascular complications (10% vs 12% vs 4%, p = 0.14) were observed. CONCLUSIONS: TAVI with self-expanding valves was safe, and device iterations may result in a lower need for PPI. More-than-mild PVL seemed to occur less often with repositionable technology. SUPPLEMENTARY INFORMATION: The online version of this article (10.1007/s12471-021-01568-5) contains supplementary material, which is available to authorized users

COMPARE LAAO: Rationale and design of the randomized controlled trial "COMPARing Effectiveness and safety of Left Atrial Appendage Occlusion to standard of care for atrial fibrillation patients at high stroke risk and ineligible to use oral anticoagulation therapy"

Contains fulltext : 252137.pdf (Publisher’s version ) (Open Access)BACKGROUND: Left atrial appendage occlusion (LAAO) provides an alternative to oral anticoagulation (OAC) for stroke prevention in patients with atrial fibrillation (AF). In patients with a long-term or permanent contraindication for OAC randomized controlled trial (RCT) data is lacking. STUDY OBJECTIVES: To assess the efficacy and safety of LAAO in AF patients who are ineligible to use OAC. The co-primary efficacy endpoint is (1) time to first occurrence of stroke (ischemic, hemorrhagic, or undetermined) and (2) time to first occurrence of the composite of stroke, transient ischemic attack (TIA), and systemic embolism (SE). The primary safety endpoint is the 30-day rate of peri-procedural complications. STUDY DESIGN: This is a multicenter, investigator-initiated, open-label, blinded endpoint (PROBE), superiority-driven RCT. Patients with AF, a CHA₂DS₂-VASc score ≥2 for men and ≥3 for women and a long-term or permanent contraindication for OAC will be randomized in a 2:1 fashion to the device- or control arm. Patients in the device arm will undergo percutaneous LAAO and will receive post-procedural dual antiplatelet therapy (DAPT) per protocol, while those in the control arm will continue their current treatment consisting of no antithrombotic therapy or (D)APT as deemed appropriate by the primary responsible physician. In this endpoint-driven trial design, assuming a 50% lower stroke risk of LAAO compared to conservative treatment, 609 patients will be followed for a minimum of 1 and a maximum of 5 years. Cost-effectiveness and budget impact analyses will be performed to allow decision-making on reimbursement of LAAO for the target population in the Netherlands. SUMMARY: The COMPARE LAAO trial will investigate the clinical superiority in preventing thromboembolic events and cost-effectiveness of LAAO in AF patients with a high thromboembolic risk and a contraindication for OAC use. NCT TRIAL NUMBER: NCT04676880

Patients with aortic stenosis referred for TAVI: treatment decision, in-hospital outcome and determinants of survival

Aims To assess treatment decision and outcome in patients referred for transcatheter aortic valve implantation (TAVI) in addition to predictive factors of mortality after TAVI. Methods Three-centre prospective observational study including 358 patients. Endpoints were defined according to the Valve Academic Research Consortium. Results Of the 358 patients referred for TAVI, TAVI was performed in 235 patients (65%), surgical aortic valve replacement (AVR) in 24 (7%) and medical therapy (MT) in 99 (28%). Reasons to decline TAVI in favour of AVR/MT were patient preference (29%), peripheral vascular disease (15%) and non-severe aortic stenosis (11%). The logistic EuroSCORE was significantly higher in patients who underwent TAVI and MT in comparison with those undergoing AVR (19 vs. 10%, p=0.007). At 30 days, all-cause mortality and the combined safety endpoint were 9 and 24% after TAVI and 8 and 25% after AVR, respectively. All-cause mortality was significantly lower in the TAVI group compared with the MT group at 6 months, 1 year and 2 years (12% vs. 22%, 21% vs. 33% and 31% vs. 55%, respectively, p<0.001). Multivariable analysis revealed that blood transfusion (HR: 1.19; 95% CI: 1.05-1.33), pre-existing renal failure (HR: 1.18; 95% CI: 1.06-1.33) and STS score (HR: 1.06; 95% CI: 1.02-1.10) were independent predictors of mortality at a median of 10 (IQR: 3-23) months after TAVI. Conclusions Approximately two-thirds of the patients referred for TAVI receive this treatment with gratifying short- and long-term survival. Another 7% underwent AVR. Prognosis is poor in patients who do not receive valve replacement therapy

The ACRA Anatomy Study (Assessment of Disability After Coronary Procedures Using Radial Access): A Comprehensive Anatomic and Functional Assessment of the Vasculature of the Hand and Relation to Outcome After Transradial Catheterization

BACKGROUND: The palmar arches serve as the most important conduits for digital blood supply, and incompleteness may lead to digital ischemia when the radial artery becomes obstructed after cardiac catheterization. The rate of palmar arch incompleteness and the clinical consequences after transradial access are currently unknown.METHODS AND RESULTS: The vascular anatomy of the hand was documented by angiography in 234 patients undergoing transradial cardiac catheterization. In all patients, a preprocedural modified Allen test and Barbeau test were performed. Upper-extremity function was assessed at baseline and 2-year follow-up by the QuickDASH. Incompleteness of the superficial palmar arch (SPA) was present in 46%, the deep palmar arch was complete in all patients. Modified Allen test and Barbeau test results were associated with incompleteness of the SPA (P=0.001 and P=0.001). The modified Allen test had a 33% sensitivity and 86% specificity for SPA incompleteness with a cutoff value of >10 seconds and a 59% sensitivity and 60% specificity with a cutoff value of >5 seconds. The Barbeau test had a 7% sensitivity and 98% specificity for type D and a 21% sensitivity and 93% specificity for types C and D combined. Upper-extremity dysfunction was not associated with SPA incompleteness (P=0.77).CONCLUSIONS: Although incompleteness of the SPA is common, digital blood supply is always preserved by a complete deep palmar arch. Preprocedural patency tests have thus no added benefit to prevent ischemic complications of the hand. Finally, incompleteness of the SPA is not associated with a loss of upper-extremity function after transradial catheterization