Citation analysis has become an important tool for research performance assessment in the medical sciences. However, different areas of medical research may have considerably different citation ...practices, even within the same medical field. Because of this, it is unclear to what extent citation-based bibliometric indicators allow for valid comparisons between research units active in different areas of medical research.
A visualization methodology is introduced that reveals differences in citation practices between medical research areas. The methodology extracts terms from the titles and abstracts of a large collection of publications and uses these terms to visualize the structure of a medical field and to indicate how research areas within this field differ from each other in their average citation impact.
Visualizations are provided for 32 medical fields, defined based on journal subject categories in the Web of Science database. The analysis focuses on three fields: Cardiac & cardiovascular systems, Clinical neurology, and Surgery. In each of these fields, there turn out to be large differences in citation practices between research areas. Low-impact research areas tend to focus on clinical intervention research, while high-impact research areas are often more oriented on basic and diagnostic research.
Popular bibliometric indicators, such as the h-index and the impact factor, do not correct for differences in citation practices between medical fields. These indicators therefore cannot be used to make accurate between-field comparisons. More sophisticated bibliometric indicators do correct for field differences but still fail to take into account within-field heterogeneity in citation practices. As a consequence, the citation impact of clinical intervention research may be substantially underestimated in comparison with basic and diagnostic research.
The coagulation system is crucial in the pathogenesis of infective endocarditis and undergoes significant changes during course of the disease. However, little is known about the implications of ...those changes in the perioperative period. Aim of the present study was to delineate the specific coagulation patterns and their clinical consequence in patients undergoing cardiac surgery due to infective endocarditis.
In this single-centre, exploratory, prospective observational study, we investigated the incidence and degree of coagulopathy in patients with (n = 31) and without infective endocarditis (n = 39) undergoing cardiac valve surgery. The primary outcome was the differences between these two groups in rotational thromboelastometry (ROTEM) results before, during and after surgery. The secondary outcomes were the differences between the groups in heparin sensitivity, bleeding complications, and transfusion requirements.
Most ROTEM parameters in EXTEM, INTEM and FIBTEM assays were significantly altered in patients with infective endocarditis. Clotting time in the EXTEM assay was significantly prolonged in the endocarditis group at all time-points, while all clot firmness parameters (A5, A10 and MCF) were significantly increased. The heparin sensitivity index was significantly lower in the endocarditis group (median index 0.99 vs 1.17s. IU-1.kg-1, p = .008), indicating increased heparin resistance. Patients with infective endocarditis had more bleeding complications as assessed by the universal definition of perioperative bleeding score (OR 3.0, p = .018), and more patients with endocarditis underwent early re-exploration (p = .018).
The findings of this exploratory investigation show significantly altered coagulation profiles in patients with infective endocarditis, with concomitant hyper- and hypocoagulability. Furthermore, the incidence of bleeding complications and transfusion requirements were increased in patients with endocarditis. These results show the potential of ROTEM to detect coagulation abnormalities in patients with infective endocarditis. Existing point-of-care coagulation testing guided algorithms for optimizing perioperative coagulation management possibly need to be adjusted for these high-risk patients undergoing cardiac surgery.
Objectives We hypothesize that concomitant tricuspid annuloplasty in patients with tricuspid annular dilatation who undergo mitral valve repair could prevent progression of tricuspid regurgitation ...and right ventricular remodeling. Methods In 2002, 80 patients underwent mitral valve repair. Concomitant tricuspid annuloplasty was performed in 13 patients with grade 3 or 4 tricuspid regurgitation. In 2004, 102 patients underwent mitral valve repair. Concomitant tricuspid annuloplasty was performed in 21 patients with grade 3 or 4 tricuspid regurgitation and in 43 patients with an echocardiographically determined tricuspid annular diameter of 40 mm or greater. Patients underwent transthoracic echocardiographic analysis preoperatively and at the 2-year follow-up. Results In the 2002 cohort right ventricular dimensions did not decrease (right ventricular long axis, 69 ± 7 vs 70 ± 8 mm; right ventricular short axis, 29 ± 7 vs 30 ± 7 mm); tricuspid regurgitation grade and gradient remained unchanged. In the 2004 cohort right ventricular reverse remodeling was observed (right ventricular long axis, 71 ± 6 vs 69 ± 9 mm; right ventricular short axis, 29 ± 5 vs 27 ± 5 mm; P < .0001); tricuspid regurgitation diminished (1.6 ± 1.0 vs 0.9 ± 0.6, P < .0001), and transtricuspid gradient decreased (28 ± 13 vs 23 ± 15 mm Hg, P = .021). Subanalysis of the 2002 cohort showed that in 23 patients without grade 3 or 4 tricuspid regurgitation but baseline tricuspid annular dilatation, the degree of tricuspid regurgitation was worse at the 2-year follow-up. Moreover, this caused right ventricular dilatation. Subanalysis of the 2004 cohort demonstrated reverse right ventricular remodeling and decreased tricuspid regurgitation in 43 patients with preoperative tricuspid annular dilatation who underwent tricuspid annuloplasty. Conclusions Concomitant tricuspid annuloplasty during mitral valve repair should be considered in patients with tricuspid annular dilatation despite the absence of important tricuspid regurgitation at baseline because this improves echocardiographic outcome.
Objectives This study examined the mid-term hemodynamic and clinical impact of prosthesis–patient mismatch (PPM) in patients undergoing transcatheter aortic valve implantation (TAVI) with ...balloon-expandable valves. Background PPM can be observed after aortic valve surgery. However, little is known about the incidence of PPM in patients undergoing TAVI. Methods Echocardiography and clinical assessment were performed in 165 patients at baseline, before hospital discharge, and at 6 months after TAVI. PPM was defined as an indexed effective orifice area ≤0.85 cm2 /m2. Results Thirty patients (18.2%) showed PPM before hospital discharge. At baseline, patients with PPM had a larger body surface area (1.84 ± 0.18 m2 vs. 1.73 ± 0.18 m2 , p = 0.003) and a greater severity of aortic stenosis (indexed valve area 0.35 ± 0.09 cm2 /m2 vs. 0.40 ± 0.10 cm2 /m2 , p = 0.005) than patients without PPM. Patients with PPM demonstrated a slower and smaller reduction in mean transaortic gradient, limited left ventricular (LV) mass regression, and left atrial volume reduction over 6 months compared with patients without PPM. LV filling pressure, measured by E/e′, tended to remain elevated in patients with PPM. Importantly, a higher proportion of patients with PPM did not improve in New York Heart Association functional class compared with patients without PPM (36.7% vs. 1.5%, p < 0.001), although major adverse valve-related and cardiovascular events did not differ between the 2 groups. Conclusions PPM may be observed after TAVI and when present may be accompanied by less favorable changes in transvalvular hemodynamics, limited LV mass regression, persistent elevated LV filling pressure, and less improvement in clinical functional status.
INTELLiVENT-Adaptive Support Ventilation (ASV) is a closed-loop ventilation mode that uses capnography to adjust tidal volume (V.sub.T) and respiratory rate according to a user-set end-tidal CO.sub.2 ...(etCO.sub.2) target range. We compared sidestream versus mainstream capnography with this ventilation mode with respect to the quality of breathing in patients after cardiac surgery. Single-center, single-blinded, non-inferiority, randomized clinical trial in adult patients scheduled for elective cardiac surgery that were expected to receive at least two hours of postoperative ventilation in the ICU. Patients were randomized 1:1 to closed-loop ventilation with sidestream or mainstream capnography. Each breath was classified into a zone based on the measured V.sub.T, maximum airway pressure, etCO.sub.2 and pulse oximetry. The primary outcome was the proportion of breaths spent in a predefined 'optimal' zone of ventilation during the first three hours of postoperative ventilation, with a non-inferiority margin for the difference in the proportions set at -20%. Secondary endpoints included the proportion of breaths in predefined 'acceptable' and 'critical' zones of ventilation, and the proportion of breaths with hypoxemia. Of 80 randomized subjects, 78 were included in the intention-to-treat analysis. We could not confirm the non-inferiority of closed-loop ventilation using sidestream with respect to the proportion of breaths in the 'optimal' zone (mean ratio 0.87 0.77 to infinity; P = 0.116 for non-inferiority). The proportion of breaths with hypoxemia was higher in the sidestream capnography group versus the mainstream capnography group. We could not confirm that INTELLiVENT-ASV using sidestream capnography is non-inferior to INTELLiVENT-ASV using mainstream capnography with respect to the quality of breathing in subjects receiving postoperative ventilation after cardiac surgery.
Despite a successful surgical procedure and adherence to current recommendations, postoperative left ventricular (LV) dysfunction after mitral valve repair (MVr) for organic mitral regurgitation (MR) ...may still occur. New approaches are therefore needed to detect subclinical preoperative LV dysfunction. LV global longitudinal strain (GLS), assessed with speckle-tracking echocardiographic analysis, has been proposed as a novel measure to better depict latent LV dysfunction. The aim of this study was to investigate the value of GLS to predict long-term LV dysfunction after MVr.
A total of 233 patients (61% men, 61 ± 12 years) with moderate-severe organic MR who underwent successful MVr between 2000 and 2009 were included. Echocardiography was performed at baseline and long-term follow-up (34 ± 20 months) after MVr. LV dysfunction at follow-up was defined as LV ejection fraction (EF) <50% and was present in 29 (12%) patients. A cut-off value of -19.9% of GLS showed a sensitivity and specificity of 90 and 79% to predict long-term LV dysfunction. By univariate logistic regression analysis, baseline LVEF ≤60%, LV end-systolic diameter (ESD) ≥40 mm, atrial fibrillation, presence of symptoms, and GLS >-19.9% were predictors of long-term LV dysfunction. By multivariate analysis, GLS remained an independent predictor of LV dysfunction (odds ratio 23.16, 95% confidence interval: 6.53-82.10, P < 0.001), together with LVESD.
In a large series of patients operated within the last decade, MVr resulted in a low incidence of long-term LV dysfunction. A GLS of >-19.9% demonstrated to be a major independent predictor of long-term LV dysfunction after adjustment for parameters currently implemented into guidelines.
Abstract
Aims
Recurrent mitral regurgitation (MR) has been reported after mitral valve repair for functional MR. However, the impact of recurrent MR on long-term survival remains poorly defined. In ...the present study, mortality-adjusted recurrent MR rates, the clinical impact of recurrent MR and its determinants were studied in patients after mitral valve repair with revascularization for functional MR in the setting of ischaemic heart disease.
Methods and results
Long-term clinical and echocardiographic outcome was evaluated in 261 consecutive patients after restrictive mitral annuloplasty and revascularization for moderate to severe functional MR, between 2000 and 2014. The cumulative incidence of recurrent MR ≥ Grade 2, assessed by competing risk analysis, was 9.6 ± 1.8% at 1-year, 20.3 ± 2.5% at 5-year, and 27.6 ± 2.9% at 10-year follow-up. Cumulative survival was 85.8% 95% confidence interval (CI) 81.0–90.0 at 1-year, 67.3% (95% CI 61.1–72.6%) at 5-year, and 46.1% (95% CI 39.4–52.6%) at 10-year follow-up. Age, preoperative New York Heart Association Class III or IV, a history of renal failure, and recurrence of MR expressed as a time-dependent variable HR 3.28 (1.87–5.75), P < 0.001, were independently associated with an increased mortality risk. Female gender, a history of ST-elevation myocardial infarction, a preoperative QRS duration ≥120 ms, a higher preoperative MR grade, and a higher indexed left ventricular end-systolic volume were independently associated with an increased likelihood of recurrent MR.
Conclusion
Mitral valve repair for functional ischaemic MR resulted in a low incidence of recurrent MR with favourable clinical outcome up to 10 years after surgery. Presence of recurrent MR at any moment after surgery proved to be independently associated with an increased risk for mortality.
Oral anticoagulation with vitamin K antagonists (VKA) is currently advised for a period of three months following surgical mitral valve repair, regardless of the rhythm status. The evidence ...supporting this recommendation is weak and recent studies have challenged the safety and efficacy of this recommendation. A systematic review of literature was conducted by searching PubMed, Embase, Web of Science, Emcare and Cochrane Library databases for original publications comparing the efficacy and safety of oral anticoagulation with vitamin K antagonists to antiplatelet treatment early after mitral valve surgery in patients with no atrial fibrillation. Study endpoints included thromboembolic complications, bleeding complications and survival. A total of five studies, including 5093 patients, met the inclusion criteria; 2824 patients were included in the oral anticoagulation and 2269 in the on antiplatelet treatment group. Pooled analyses demonstrated no beneficial effect of oral anticoagulation on the incidence of thromboembolic complications (risk ratio 1.14, 95% confidence interval 0.76–1.70, P=0.53, I2 = 8%). Moreover, oral anticoagulation did not result in a significantly increased risk of bleeding complications (risk ratio 0.89, 95% confidence interval 0.32 – 2.44, P=0.81, I2 = 87%). When combining the efficacy and safety endpoints, no difference was observed between groups (risk ratio 1.01, 95% confidence interval 0.51–1.97, P=0.99 I2 = 85%). Likewise, mortality did not differ between groups (risk ratio 0.89, 95% confidence interval 0.15–5.23, P=0.90 I2 = 71%). Our results confirmed the safety but failed to confirm the efficacy of oral anticoagulation in patients undergoing mitral valve surgery. A randomized controlled trial would provide the evidence needed to support treatment recommendations.
PDF
