Temporal changes of soluble ST2 after cardiovascular interventions

BACKGROUND

Soluble ST2 (sST2), a member of the IL-1 receptor family, has been proposed as a novel biomarker with predictive value for heart failure and mortality in patients suffering from cardiovascular diseases. The influence of clinical characteristics on variability of sST2 levels is relatively unexplored. Here, we studied the effect of cardiovascular interventions and clinical characteristics on plasma sST2 expression levels.

MATERIAL AND METHODS

In the current study, sST2 levels were assessed in the plasma of patients scheduled for coronary artery bypass grafting (CABG) (n = 76), percutaneous coronary intervention (PCI) (n = 68) or peripheral vascular surgery (n = 27).

RESULTS

Age was the only classical risk factor significantly correlating with sST2 levels. Soluble ST2 levels were significantly increased 1 h after CABG (48 [33-70] vs. 61 [42-89] pg/mL, P = 0·001) and increased even further after 24 h (1116 [578-13 666] pg/mL, P < 0·001). An average threefold increase in sST2 levels was also observed in patients 24 h after peripheral interventions (30 [21-41] vs. 98 [48-211] pg/mL, P < 0·001). Two months after PCI, we found that sST2 levels were significantly higher compared with baseline levels (41 [29-61] vs. 48 [31-80] pg/mL, P = 0·007, n = 52). In addition, we did not observe an association between sST2 and any inflammatory or cardiac-specific markers that were measured in this study.

CONCLUSIONS

Soluble ST2 increases significantly following cardiovascular interventions. The notion of a recent cardiovascular intervention is a strong determinant of sST2 levels and therefore needs to be taken into account when exploring sST2 as predictor of future cardiovascular events.

The role of the Interleukin 1 receptor-like 1 (ST2) and Interleukin-33 pathway in cardiovascular disease and cardiovascular risk assessment

There is an ongoing search for biomarkers that can facilitate the diagnosis of subclinical or clinically manifest cardiovascular disease. One of the emerging biomarkers currently under investigation is ST2, which is the receptor of Interleukin-33 (IL-33). ST2 is a member of the Interleukin-1 receptor family and exists in a transmembrane (ST2L) and a soluble form (sST2) due to alternative splicing. Several groups have reported sST2 elevations in serum of cardiovascular disease patients. There is consisting evidence that sST2 is independently predictive for mortality in patients with heart failure or myocardial infarction. In addition to its potential as a biomarker for adverse cardiovascular events, ST2 is considered to play a causal role in chronic cardiovascular diseases such as atherosclerosis and heart failure. Signaling of IL-33 via ST2 has been shown to be cardioprotective in mouse models of myocardial infarction, heart transplantation and cardiac hypertrophy and fibrosis. Furthermore, treatment with IL-33 reduced the development of plaques in atherosclerotic mice. In this paper we will review the currently available literature on sST2 as a biomarker for adverse cardiovascular events. In addition, we will elaborate on the potential mechanistic role of the IL-33/ST2 pathway in chronic inflammatory cardiovascular diseases.

Appendiceal diverticulitis: a rare cause of right iliac fossa pain syndrome

Appendiceal diverticulitis is a rare pathologic entity that usually simulates acute appendicitis. However, it can present as a separate clinical entity that should be part of the differential diagnosis of right lower quadrant abdominal pain. Pre-operative diagnosis is rarely described but is important in preventing perforation and subsequent abdominal sepsis. We present a case of an atypical right iliac fossa pain syndrome caused by histologically proven appendiceal diverticulitis, pre-operatively diagnosed by computed tomography.

Quantification of mechanical ventricular dyssynchrony: direct comparison of velocity-encoded and cine magnetic resonance imaging

PURPOSE

The preoperative assessment of mechanical dyssynchrony can help to improve patient selection in candidates for cardiac resynchronization therapy (CRT). The present study compared the performance of velocity-encoded (VENC) MRI to cine-magnetic resonance imaging (MRI) for quantifying mechanical ventricular dyssynchrony.

MATERIALS AND METHODS

VENC-MRI and cine-MRI were performed in 20 patients with heart failure NYHA class III and reduced ejection fraction (median: 24 %, interquartile range: 18 - 28 %) before CRT device implantation. The interventricular mechanical delay (IVMD) was assessed by VENC-MRI as the temporal difference between the onset of aortic and pulmonary flow. Intraventricular dyssynchrony was quantified by cine-MRI, using the standard deviation of time to maximal wall thickening in sixteen left ventricular segments (SDt-16). The response to CRT was assessed in a six-month follow-up.

RESULTS

14 patients (70 %) clinically responded to CRT. A similar accuracy was found to predict the response to CRT by measurements of the IVMD and SDt-16 (75 vs. 70 %; p = ns). The time needed for data analysis was significantly shorter for the IVMD at 1.69 min (interquartile range: 1.66 - 1.88 min) compared to 9.63 min (interquartile range: 8.92 - 11.63 min) for the SDt-16 (p < 0.0001).

CONCLUSION

Measurements of the IVMD by VENC-MRI and the SDt-16 by cine-MRI provide a similar accuracy to identify clinical responders to CRT. However, data analysis of the IVMD is significantly less time-consuming compared to data analysis of the SDt-16.

Factors associated with medication adherence to oral hypoglycaemic agents in different ethnic groups suffering from type 2 diabetes: a systematic literature review and suggestions for further research

AIMS

To synthesize knowledge regarding the different factors that may influence adherence to oral hypoglycaemic agents in different ethnic groups through a systematic review of the literature.

METHODS

Thirteen databases were searched and 1201 articles were screened by two authors independently from each other. Different quantitative study designs were included if the study population included at least one ethnic group other than White people, medication adherence was a dependent variable and a clear description was given of the method used to measure medication adherence.

RESULTS

Demographic, disease-related and treatment-related, socio-economic and cultural factors were associated with medication adherence in the populations that were studied. However, to synthesize results, the number of studies was too small and the included studies differed too much with respect to their study designs and the ethnic groups that were studied. We discuss several methodological challenges with respect to measuring medication adherence, measuring ethnicity and study designs that need to be resolved to make future studies comparable. We propose methodological improvements for future research.

CONCLUSION

Although medication adherence is an essential part of the diabetic regimen, little is known about the association between ethnicity and medication adherence and the underlying factors that could explain this association. More research is needed in which important methodological challenges will have to be faced.

[Catheter ablation for atrial fibrillation: clinically established or still an experimental method]

Interventional treatment for atrial fibrillation has been introduced as a therapeutic option since the pulmonary veins (PV) have been discovered as the dominant sources of paroxysmal atrial fibrillation (PAF). Elimination of PV conduction is the initial goal during catheter ablation in this setting. The success rate after the initial procedure varies between 60 and 85 %, with more than 80 % after subsequent interventions. Supported by the current guidelines, interventional treatment of AF is indicated in case of symptomatic arrhythmias refractory to antiarrhythmic treatment. The introduction of the combined, stepwise approach has been another important breakthrough with regard to the treatment of chronic persistent atrial fibrillation (CAF). This strategy includes the combination of all conventional ablation strategies (PV isolation, ablation of complex fractionated atrial electrograms, linear ablation) with the goal of AF termination. The first procedure for CAF treatment is quite frequently also only the first step towards stable sinus rhythm with a favourable outcome after AF termination (&gt; 80 % sinus rhythm). In more than half of the patients predominantly other atrial arrhythmias than AF have to be targeted in a second procedure. This approach is currently under clinical investigation and so far not "clinically established" due to the fact that it is a quite time consuming and challenging procedure even in experienced centres. Future studies may help to identify predictors for procedure failure (e.g. LA size, AF duration, atrial cycle length, spectral analysis) in order to improve patient selection. Additionally, it has to be underscored, that in paroxysmal atrial fibrillation the relatively high recurrence rate after the first procedure still is the subject of further investigations. This aspect might be improved by the introduction of novel strategies (i.e. testing of concealed PV conduction after ablation with adenosine) or new technologies (i.e. robotic navigation) for PAF ablation.

Azithromycin reduces pulmonary fibrosis in a bleomycin mouse model

Idiopathic pulmonary fibrosis (IPF) is a devastating disease without proper treatment. Despite intensive research, the exact underlying pathogenesis remains elusive. It is regarded as a continuous injury, resulting in inflammation, infiltration, and proliferation of fibroblasts and extracellular matrix deposition, leading to an irreversible restrictive lung function deterioration and death. In this study the effect of azithromycin, a macrolide antibiotic on bleomycin-induced pulmonary fibrosis was investigated. C57BL/6 mice were intratracheally instilled with bleomycin (0.5 mg/kg) or saline. In the bleomycin group, half of the animals received azithromycin every other day from day 1 on. Bronchoalveolar lavage and histology were performed at days 7 and 35, and pulmonary function tests on day 35. At day 35, fibrotic lesions (spindle cell proliferation/collagen I deposition) were paralleled by a restrictive lung function pattern. Alterations were found in neutrophils and macrophages (innate immunity) and in T(H)2, T(H)17, and Treg cytokines (adaptive immunity). Azithromycin significantly reduced both fibrosis and the restrictive lung function pattern. This study demonstrated a beneficial effect of azithromycin on bleomycin-induced pulmonary fibrosis. A possible mechanism could be a modulation of both innate immunity and adaptive immunity. These findings might suggest a potential role for azithromycin in the treatment of IPF.

[Registry and studies of the German Competence Network on Atrial Fibrillation (AFNET)]

The German Competence Network on Atrial Fibrillation (AFNET) is a national interdisciplinary research network funded by the Federal Ministry of Education and Research (BMBF). AFNET was initiated in 2003 and aims at improving treatment of atrial fibrillation (AF), the most frequent sustained cardiac arrhythmia. AFNET has established a nationwide patient registry on diagnostics, therapy, course and complications of AF in Germany. The data analyzed to date demonstrate that patients with AF are likely to have multiple co-morbidities, such as hypertension, valvular heart disease, coronary artery disease, diabetes mellitus and advanced age. Oral anticoagulation is provided to the majority of patients in accordance with the recommendations given by guidelines. Further areas of research deal with the optimal duration of antiarrhythmic therapy following electrical cardioversion of atrial fibrillation and the value of strategies to prevent arrhythmogenic changes, such as fibrosis in the atria, for prevention of further episodes of atrial fibrillation. Additional registry projects were established for patients with catheter-based interventional therapy of atrial fibrillation and surgical ablation to define success, complications and long term results of these recently developed procedures more clearly. Data and insights gathered from these projects were used to further develop standards of care in two international conferences.

[Interventional therapy of atrial fibrillation: possibilities and limitations]

Recently, significant progress has been made treating atrial fibrillation (AF) with catheter ablation emerging as an increasingly important technique. Electrical disconnection of the pulmonary veins (PV) is a widely accepted endpoint for interventional treatment of paroxysmal AF (PAF). According to the current guidelines, catheter ablation can be considered as a therapeutic option in patients who failed antiarrhythmic drug treatment for PAF. The procedural endpoint for PVI is achievement of permanent electrical isolation of the PVs, which in the vast majority of patients harbor triggered electrical activity inducing and maintaining PAF. The success rate of this approach in patients with PAF ranges between 60 and 80% after a single procedure and augments to > 80 % in patients undergoing a repeat procedure to abolish recovered PV connection. However, it is now evident that persistent or long-standing persistent AF may not be successfully treated by PVI alone since the majority of patients have AF maintaining substrate beyond the PV. From a pathophysiological perspective this is explained by structural and electrical remodeling of the atrial myocardium in patients with persistent AF. Therefore, it is today widely accepted that additional substrate modification is required to effectively address persistent AF using catheter ablation. It has been shown that a combined approach of PV isolation, ablation of fractionated atrial electrograms and application of lines to treat atrial macro-reentrant tachycardias ("stepwise approach") aiming for restoration of sinus rhythm is a favorable strategy to treat persistent AF. However, significant expertise is needed to accomplish all steps within these complex procedures. Therefore, catheter ablation for persistent AF cannot yet be considered "clinically established" and should only be performed in high volume centers. Additional data is needed to verify the beneficial effect of this strategy and determine "predictors" identifying patients profiting most from these ablation strategies. In patients with PAF, catheter ablation has emerged as an established therapy also in comparison to antiarrythmic drug treatment. Recent studies have shown that catheter ablation for PAF is superior to antiarrhythmic drug treatment with regard to mid-term suppression of any atrial arrhythmia. Overall, catheter ablation for AF has still to be considered as a symptomatic treatment since evidence for beneficial effects with regard to more robust clinical endpoints such as death, rehospitalization and ischemic cerebral events are not yet available.