A multi-site coronary sampling study on CRP in non-STEMI: Novel insights into the inflammatory process in acute coronary syndromes

Differences in Cardiac Troponin T Composition in Myocardial Infarction and End-Stage Renal Disease Patients: A Blood Tube Effect?

BACKGROUND

Cardiac troponin T (cTnT) is key in diagnosing myocardial infarction (MI) but is also elevated in end-stage renal disease (ESRD) patients. Specific larger cTnT proteoforms were identified for the acute phase of MI, while in serum of ESRD patients solely small cTnT fragments were found. However, others allocated this to a pre-analytic effect due to abundant thrombin generation in serum. Therefore, we investigated the effect of various anticoagulation methods on cTnT composition and concentration and compared the cTnT composition of MI and ESRD patients.

METHODS

The agreement of cTnT concentrations between simultaneously collected serum, lithium-heparin (LH) plasma, and ethylenediaminetetraacetic acid (EDTA) plasma was studied using the high-sensitivity (hs-)cTnT immunoassay. cTnT proteoform composition was investigated in a standardized time-dependent manner through spike experiments and in simultaneously collected blood matrixes of MI and ESRD patients.

RESULTS

Excellent hs-cTnT concentration agreements were observed across all blood matrixes (slopes > 0.98; 95% CI, 0.96-1.04). Time-dependent degradation (40 kDa intact:29 kDa fragment:15 to 18 kDa fragments) was found in LH plasma and EDTA plasma, and serum in ratios (%) of 90:10:0, 0:5:95, and 0:0:100, respectively (48 h after blood collection). Moreover, gel filtration chromatography (GFC) profiles illustrated mainly larger cTnT proteoforms in MI patients, while in ESRD patients mainly 15 to 18 kDa fragments were found for all matrices.

CONCLUSIONS

The extent of cTnT degradation in vitro is dependent on the (anti)coagulation method, without impacting hs-cTnT concentrations. Furthermore, mainly larger cTnT proteoforms were present in MI patients, while in ESRD patients mainly small 15 to 18 kDa cTnT fragments were found. These insights are essential when developing a novel hs-cTnT assay targeting larger cTnT proteoforms.

Evaluating the systemic immune-inflammation index for in-hospital and long-term mortality in elderly non-ST-elevation myocardial infarction patients

INTRODUCTION

This investigation aimed to evaluate the predictive value of the systemic immune-inflammation index (SII) for in-hospital and long-term mortality in elderly patients with non-ST-elevation myocardial infarction (NSTEMI).

METHODS

This retrospective investigation included 314 consecutive elderly NSTEMI patients in a tertiary center. SII is computed as (neutrophils × platelets)/lymphocytes. Based on the increased SII values, we classified the research sample into three tertile groups as T1, T2, and T3. The in-hospital and long-term mortality were defined as the primary outcomes.

RESULTS

Patients in the T3 group had lower chances of survival in the in-hospital and long-term periods compared with those in the T2 and T1 groups. According to the multivariable Cox regression models, SII independently related with in-hospital (hazard ratio (HR): 1.001, 95% CI: 1.000-1.1003, p = 0.038) and long-term mortality (HR: 1.004, 95% CI: 1.002-1.006, p < 0.001). To predict long-term mortality, the optimal SII value was > 2174 with 80% sensitivity and 85.4% specificity. SII had a slightly lower but statistically non-inferior discriminative ability for long-term mortality compared with the Charlson comorbidity index (CCI) in the receiver operating characteristic curve comparison (AUC: 86.2 vs. AUC: 890, p > 0.05). Additionally, combining SII with traditional risk factors and the CCI revealed a significant improvement in C-statistics.

CONCLUSION

This investigation may be the first to demonstrate that SII is independently linked with in-hospital and long-term mortality in elderly NSTEMI patients.

Dynamic Changes in Pentraxin-3 and Neprilysin in ST Segment Elevation Myocardial Infarction

Pentraxin-3 (PTX3) and neprilysin have been associated with increased morbidity and mortality in chronic inflammatory disease and heart failure, but these biomarkers have been studied less in patients with ST segment elevation myocardial infarction (STEMI). We investigated the dynamic changes in these biomarkers, as well as the well-known C-reactive protein (CRP), in STEMI patients. PTX3, neprilysin and CRP were measured in samples from 165 STEMI patients, collected at the acute stage, 1–3 days after and 3 months after percutaneous coronary intervention (PCI), and from 40 healthy donors. Patient survival was followed for approximately 8 years after the PCI. As compared with samples from healthy donors, plasma levels of CRP and PTX3 were significantly increased in the acute samples and 1–3 days after PCI, but not at 3 months. CRP levels peaked at 1–3 days, while PTX3 was similarly high in both acute and 1–3 days samples. For neprilysin, no significant differences were observed at the group level. We found no significant differences when comparing patients with patent versus occluded culprit vessels or between patients having a thrombus aspiration or not. However, we found a significant reduction in survival for individuals with PTX3 above the median, both for samples collected at the acute stage and 1–3 days after PCI (p = 0.0001 and p = 0.0008, respectively). For CRP, no significant differences were observed using this approach, but patients above the reference range for healthy donors in the acute samples showed significantly lower survival (p = 0.0476). Conclusions: Survival analysis suggests that PTX3 might be a promising marker to predict mortality in this patient population.

Association between gaseous air pollutants and biomarkers of systemic inflammation: A systematic review and meta-analysis

BACKGROUND

Studies have linked gaseous air pollutants to multiple health effects via inflammatory pathways. Several major inflammatory biomarkers, including C-reactive protein (CRP), fibrinogen, interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) have also been considered as predictors of cardiovascular disease. However, there has been no meta-analysis to evaluate the associations between gaseous air pollutants and these typical biomarkers of inflammation to date.

OBJECTIVES

To evaluate the overall associations between short-term and long-term exposures to ambient ozone (O₃), nitrogen dioxide (NO₂), sulfur dioxide (SO₂), carbon dioxide (CO) and major inflammatory biomarkers including CRP, fibrinogen, IL-6 and TNF-α.

METHODS

A meta-analysis was conducted for publications from PubMed, Web of Science, Scopus and EMBASE databases up to Feb 1st, 2021.

RESULTS

The meta-analysis included 38 studies conducted among 210,438 participants. Generally, we only observed significant positive associations between short-term exposures to gaseous air pollutants and inflammatory biomarkers. For a 10 μg/m³ increase in short-term exposure to O₃, NO₂, and SO₂, there were significant increases of 1.05% (95%CI: 0.09%, 2.02%), 1.60% (95%CI: 0.49%, 2.72%), and 10.44% (95%CI: 4.20%, 17.05%) in CRP, respectively. Meanwhile, a 10 μg/m³ increase in NO₂ was also associated with a 4.85% (95%CI: 1.10%, 8.73%) increase in TNF-α. Long-term exposures to gaseous air pollutants were not statistically associated with these biomarkers, but the study numbers were relatively small. Subgroup analyses found more apparent associations in studies with better study design, higher quality, and smaller sample size. Meanwhile, the associations also varied across studies conducted in different geographical regions.

CONCLUSION

Short-term exposure to gaseous air pollutants is associated with increased levels of circulating inflammatory biomarkers, suggesting that a systemic inflammatory state is activated upon exposure. More studies on long-term exposure to gaseous air pollutants and inflammatory biomarkers are warranted to verify the associations.

Cardiac Troponin Composition Characterization after Non ST-Elevation Myocardial Infarction: Relation with Culprit Artery, Ischemic Time Window, and Severity of Injury

BACKGROUND

Troponin composition characterization has been implicated as a next step to differentiate among non-ST elevation myocardial infarction (NSTEMI) patients and improve distinction from other conditions with troponin release. We therefore studied coronary and peripheral troponin compositions in relation to clinical variables of NSTEMI patients.

METHODS

Samples were obtained from the great cardiac vein (GCV), coronary sinus (CS), and peripheral circulation of 45 patients with NSTEMI. We measured total cTnI concentrations, and assessed both complex cTnI (binary cTnIC + all ternary cTnTIC forms), and large-size cTnTIC (full-size and partially truncated cTnTIC). Troponin compositions were studied in relation to culprit vessel localization (left anterior descending artery [LAD] or non-LAD), ischemic time window, and peak CK-MB value.

RESULTS

Sampling occurred at a median of 25 hours after symptom onset. Of total peripheral cTnI, a median of 87[78-100]% consisted of complex cTnI; and 9[6-15]% was large-size cTnTIC. All concentrations (total, complex cTnI, and large-size cTnTIC) were significantly higher in the CS than in peripheral samples (P < 0.001). For LAD culprit patients, GCV concentrations were all significantly higher; in non-LAD culprit patients, CS concentrations were higher. Proportionally, more large-size cTnTIC was present in the earliest sampled patients and in those with the highest CK-MB peaks.

CONCLUSIONS

In coronary veins draining the infarct area, concentrations of both full-size and degraded troponin were higher than in the peripheral circulation. This finding, and the observed associations of troponin composition with the ischemic time window and the extent of sustained injury may contribute to future characterization of different disease states among NSTEMI patients.

C-Reactive Protein Apheresis as Anti-inflammatory Therapy in Acute Myocardial Infarction: Results of the CAMI-1 Study

Background: C-reactive protein (CRP) is a well-known marker of inflammation. It is less known that CRP mediates tissue damage in acute myocardial infarction (AMI) thus potentially worsening prognosis. A newly developed specific CRP adsorber allows efficient lowering of CRP levels and may improve survival.

Objectives: Aim of this multi-center, controlled, non-randomized first-in-man CRP apheresis in Acute Myocardial Infarction study (CAMI-1) was to investigate the relationship between CRP levels (CRP gradient), myocardial infarct size and function as well as safety and efficacy of CRP apheresis in the setting of acute ST-segment Elevation Myocardial Infarction (STEMI) in humans.

Methods: Eighty-three patients (45 apheresis, 38 controls) were recruited. CRP apheresis was performed 24 ± 12, 48 ± 12, and optionally 72 ± 12 h after onset of symptoms. First aphereses were performed at a median CRP concentration of 23.0 mg/L (range 9–279). In each apheresis session, 5,900 ± 400 mL plasma was processed via peripheral venous access. Primary study endpoint was a reduction in myocardial infarct size after STEMI as determined by cardiovascular magnetic resonance (CMR).

Results: In controls, the CRP concentration significantly correlated with infarct size (p = 0.002) and decreased myocardial function (p ≤ 0.001). The CRP concentration in apheresis patients did not correlate with infarct size (p = 0.66) or left ventricular (LV) function (p = 0.79) and global strains and therefore significantly differed from controls (p = 0.03 and p = 0.002). Three major adverse cardiac events occurred in the control group after 12 months, none occurred in the apheresis group. Mean CRP depletion achieved over all apheresis procedures was 53.0 ± 15.1%. Apheresis sessions were well-tolerated. Reduced infarct size in the apheresis group compared to the control group (primary endpoint) was not achieved according to the original statistical analysis plan. Taking into account the individual CRP levels, however, revealed significant results. Modifications of the analysis plan were introduced in order to recruit a sufficient number of patients.

Conclusions: This pilot study in humans reveals a correlation between CRP concentration and myocardial infarct size. CRP concentrations in STEMI can effectively be reduced by CRP apheresis without relevant side effects. CRP apheresis has the potential to interfere with deleterious aspects of STEMI. By lowering CRP levels, it resulted in the loss of correlation of CRP concentrations with myocardial infarct sizes as well as LV function. These results encourage a larger, randomized clinical trial.

Clinical Trial Registration:https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00008988, DRKS00008988.