Interlaboratory reproducibility of a touch-transfer assay for the assessment of antimicrobial surfaces

BACKGROUND

Various assay methods have been developed to study antimicrobial activity based on contamination of surfaces with different amounts of liquid bacterial suspensions. Since surfaces with frequent hand contact are typically touched in a dry state in clinical settings, these tests may be inappropriate at assessing effectiveness to reduce pathogen transmission.

AIM

To investigate a surface previously confirmed to display antimicrobial activity even after drying of small volumes of bacterial suspension (Egger antimicrobial surfaces: EAS) under conditions modelling dry contamination using a touch-transfer method.

METHODS

EAS, an antimicrobial copper alloy, as well as a negative control were examined to assess interlaboratory test reproducibility.

FINDINGS

Significantly fewer bacteria on EAS after touch transfer and some differences in the touch transmission were detected between the two laboratories. However, an identical assessment of effectiveness for EAS came from both laboratories. Interestingly, despite previously detected antimicrobial efficacy of EAS and the antimicrobial copper alloy after liquid contamination, insufficient activity was observed under dry conditions during a contact time of 4 h by both laboratories. Experiments under standardized air humidity in one laboratory revealed at least for copper a strong influence of humidity on antimicrobial activity. These data indicate that procedures involving contamination of surfaces with organisms suspended in liquids are not directly comparable to dry contamination.

CONCLUSION

Since, in the real world of a hospital, organisms are typically transferred between dry surfaces, further standardization of the touch-transfer method is worthwhile for a better understanding of the efficacy of such surfaces.

Temporal trends and outcomes in ST-segment elevation myocardial infarction: a cardiac magnetic resonance imaging study over the course of 15 years

Aims

Development of evidence-based treatments in ST-elevation myocardial infarction (STEMI) patients during the last 30 years have been associated with improved outcome; however, there are data suggesting a plateauing since around 2008 (1). Moreover, contemporary data are very scarce regarding the temporal trends of infarct outcomes. This study sought to describe the temporal trends in infarct severity at myocardial tissue level over the course of 15 years by means of cardiac magnetic resonance imaging (MRI).

Methods

This study analyzed STEMI patients treated with percutaneous coronary intervention (PCI) in our Medical University who underwent a cardiac MRI between 2005 and 2021. The 15-year study period was divided into sequential 2-years blocks. Infarct characteristics were measured using MRI at 3 days [IQR 2–5] after PCI.

Results

A total of 844 STEMI patients (17% female) with a median age of 57 (interquartile range [IQR]: 51–66) years were included. The rate of evidence-based treatments was high for aspirin (99%), P2Y12i (99%), beta-blockers (91%), ACEi/ATi (92%) and statins (100%) and did not change significantly over the study period (p>0.05) with the exception for ACEi/ATi (p=0.03) and prasugrel (p<0.001), which increased and clopidogrel, which decreased during the study course (p<0.001). TIMI risk score did not change over the study period (p=0.43). Overall median infarct size was 16 [9–25]% and did not change (p=0.39) significantly. MVO, a marker of severe reperfusion injury, was also comparable (p=0.16). Accordingly, LV ejection fraction remained virtually unchanged (p=0.23)

Conclusion

Although further implementation of evidence-based treatments was seen also during the last 15 years, there has been no effect on infarct size, reperfusion injury and LV ejection fraction for patients who undergo primary PCI due to STEMI. Novel treatment strategies are needed to address this unmet therapeutic need.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Austrian Science Fund (FWF)Austrian Society of Cardiology

Prognostic significance of left ventricular functional parameters in relation to infarct location after ST-elevation myocardial infarction

Aims

In survivors of ST-elevation myocardial infarction (STEMI), the impact of infarct location on the prognostic significance of left ventricular functional parameters is not well established. The aim of this study was to investigate the prognostic relevance of left ventricular (LV) functional parameters in relation to infarct location in STEMI patients treated with contemporary primary percutaneous coronary intervention (PCI).

Methods

This observational study analyzed 803 patients with STEMI that underwent a cardiac magnetic resonance imaging scan in median 3 (interquartile range [IQR]: 2–5) days after primary PCI. The following LV functional parameters were evaluated: LV ejection fraction, LV global longitudinal strain, fast manual long-axis strain (LAS) and mitral annular plane systolic excursion (MAPSE). Primary endpoint was the occurrence of major adverse cardiac events (MACE) defined as composite of death, re-infarction and congestive heart failure.

Results

Three hundred and sixty nine patients (46%) had anterior STEMI. These patients had lower LV functional parameters including LV ejection fraction (p<0.001), LV global longitudinal strain (p<0.001), LAS (p<0.001) and MAPSE (p<0.014). MACE was evaluated at a median of 13 (IQR: 12–37) months after STEMI and occurred in 78 patients (10%). In receiver operating curve analysis, the predictive value of LV ejection fraction, LV global longitudinal strain, LAS and MAPSE was 0.59 (p=0.013), 0.64 (p<0.001), 0.67 (p<0.001) and 0.66 (p<0.001), respectively. When divided according to infarct location, MACE occurred in 47 (13%) anterior STEMI patients, and in 31 (7%) non-anterior STEMI patients, respectively. Area under the curve for the prediction of MACE in anterior vs. non-anterior STEMI was 0.59 vs 0.55 for LV ejection fraction, 0.61 vs 0.63 for LV global longitudinal strain, 0.69 vs 0.62 for LAS and both 0.66 for MAPSE. In multivariable analysis, LAS was independently associated with an increased risk of MACE (hazard ratio: 1.20; 95% confidence interval: 1.10–1.30; p<0.001) in anterior STEMI, whereas in non-anterior STEMI, LV global longitudinal strain was an independent predictor of MACE (hazard ratio: 1.22; 95% confidence interval: 1.08–1.38; p=0.002).

Conclusion

Fast manual LAS emerged as independent predictor of MACE in anterior STEMI treated with contemporary primary PCI whereas LV global longitudinal strain was independently associated with MACE in non-anterior STEMI.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Austrian Society of Cardiology

Association between inflammation and left ventricular thrombus formation following ST-elevation myocardial infarction

Background

Current evidence suggests a link between the inflammatory state and left ventricular thrombus (LVT) formation following ST-elevation myocardial infarction (STEMI). However, a comprehensive study investigating the association between inflammatory biomarkers and LVT diagnosed by cardiac magnetic resonance (CMR) is lacking.

Purpose

The present study aimed to investigate the association of biochemical markers of inflammation with LVT as assessed by CMR imaging among patients with STEMI.

Methods

We studied 309 patients with acute STEMI treated with primary percutaneous coronary intervention (pPCI) from the prospective MARINA-STEMI cohort study. Concentrations of high-sensitivity C-reactive protein (hs-CRP), interleukin-6 (IL-6), white blood cell count (WBCc), fibrinogen and D-dimer were measured two days after STEMI. Infarct characteristics and presence of LVT were assessed with the use of contrast-enhanced CMR at a median of 4 (interquartile range [IQR] 3–5) days after pPCI.

Results

In total, 309 STEMI patients (18% female) with a median age of 57 (IQR 52–65) years were included. An LVT was observed in 8% (n=24) of the overall cohort and in 15% of patients with an anterior STEMI. Hs-CRP (OR: 2.16, 95% CI: 1.54–3.02, p<0.001), IL-6 (OR: 2.38, 95% CI: 1.48–3.81, p<0.001) and fibrinogen levels (OR: 2.05, 95% CI: 1.40–3.00, p<0.001) were significantly associated with presence of LVT. Among all assessed inflammatory biomarkers, only hs-CRP was independently associated with LVT after adjustment for markers of inflammation and CMR parameters (OR: 1.77, 95% CI: 1.21–2.59, p=0.004).

Conclusion

In patients with STEMI treated with pPCI, inflammatory markers (hs-CRP, IL-6 and fibrinogen) are associated with the presence of LVT. However, only hs-CRP was independently associated with the occurrence of LVT, highlighting the key role of CRP as clinical risk marker for LVT formation in STEMI patients treated with pPCI.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): Austrian Science Fund (FWF)Austrian Society of Cardiology

Preliminary data on a fully automated left ventricular late gadolinium enhancement detection by a convolutional neuronal network in chronic myocardial infarction

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): FWF- Der Wissenschaftsfonds

Aim

To compare a fully automated segmentation of left ventricular late gadolinium enhancement (LGE) as evaluated by a convolutional neuronal network (CNN) with manual segmentation in chronic myocardial infarction.

Methods

Cardiac magnetic resonance imaging including two-dimensional LGE imaging was performed in 191 patients on a 1.5 T clinical scanner 12 months after ST-elevation myocardial infarction. LGE images were presented to a trained CNN for automated determination of left ventricular myocardium and consequently absolute LGE volume. Manual LGE segmentation according to the +5-SD method was used as reference standard. Image quality was assessed according to a 3-point Likert scale (2 = perfect image quality, 1 = some artifacts witout impaired LGE delineation, 0 = strong artifacts with impaired LGE delineation). Regression and Bland-Altman analysis were performed.

Results

In 191 included patients (182 male, mean age 57 years) LGE volume was 9.7 [IQR 3.6 to 16.2] ml according to manual segmentation and 8.3 [3.2 to 17.6] ml according to CNN segmentation. Bland-Altman analysis showed little average difference (-0.5 ml, p=0.257), however, limits of agreement ranged from -18.4 ml to 17.5 ml. Linear correlation was fair (0.57, p<0.001). Subgroup analysis according to image quality showed comparable performance of CNN segmentation in all three groups.

Conclusion

Our fully automated LGE segmentation based on a CNN in two-dimensional data sets provides measurements with little average difference compared to very time-consuming manual segmentations. However, dispersion is substantially and limits the current application of this approach on a per-patient basis. Image quality does not affect CNN performance.

C-reactive protein velocity predicts microvascular pathology after acute ST-elevation myocardial infarction

Background

The role of C-reactive protein velocity (CRPv) as an early and sensitive marker of an excessive inflammatory response in the setting of acute ST-elevation myocardial infarction (STEMI) is only poorly understood.

Purpose

The aim of this study was to investigate, in patients with STEMI treated with primary percutaneous coronary intervention (PCI), the association of CRPv with microvascular infarct pathology.

Methods

This prospective cohort study included a total of 316 patients with STEMI undergoing PCI. CRPv was defined as the difference between CRP 24±8h and CRP at hospital admission, divided by the time (in h) that have passed during the two examinations. The association of biomarker levels with cardiac magnetic resonance (CMR)-determined microvascular obstruction (MVO) was evaluated. CMR was performed at a median of 3 [interquartile range 2–4] days after PCI.

Results

After adjustment for cardiac troponin T (cTnT), culprit lesion location and TIMI-flow post-PCI, CRPv (odds ratio 3.36, 95% confidence interval (CI) 1.72–6.57; p<0.001) remained significantly associated with the occurrence of MVO. CRPv (area under the curve [AUC] 0.76, 95% CI 0.71–0.81; p<0.001) was a better predictor for MVO compared to 24h CRP (AUC difference: 0.03, p=0.002). The addition of CRPv to peak cTnT resulted in a higher AUC for MVO prediction than peak cTnT alone (AUC 0.86, 95% CI 0.82–0.90; p<0.001 vs. AUC 0.84, 95% CI 0.79–0.88; p<0.001. AUC difference: 0.02, p=0.042).

Conclusions

In patients with STEMI treated with primary PCI, CRPv was associated with microvascular infarct pathology with a predictive value incremental to cTnT, suggesting CRPv as an early and sensitive biomarker for more severe infarct pathology and outcome.

Funding Acknowledgement

Type of funding sources: None. ROC analysis for the prediction of MVO.CRPv (median) and clinical outcome.

Correlation between invasive and non-invasive quantification of myocardial amyloid load in cardiac transthyretin amyloidosis

Background

Cardiac transthyretin (ATTR) amyloidosis is an infiltrative disease caused by the extracellular deposition of misfolded ATTR protein in the myocardium. Early disease recognition and accurate description of cardiac involvement are fundamental, as cardiac ATTR amyloidosis is associated with poor prognosis. Although endomyocardial biopsy (EMB) remains the gold standard in amyloid detection and typing, non-invasive imaging can provide an accurate diagnostic tool. Bone scintigraphy enables early disease detection with high accuracy. However, it remains to be determined whether the degree of cardiac tracer uptake on bone scintigraphy correlates with the extent of histologic amyloid burden in EMB.

Aim

This single center observational study aimed to compare the histological amyloid load in endomyocardial biopsies with the quantification of cardiac tracer uptake on 99mTechnetium-3,3-diphosphono-1,2-propanodicarboxylic acid (99mTc-DPD) scintigraphy in cardiac ATTR amyloidosis.

Methods

23 patients with cardiac ATTR amyloidosis were enrolled. Diagnosis was obtained with a combination of invasive and non-invasive methods. Perugini score, mean left ventricular tracer uptake (LV uptake) and left ventricular to corpus sterni uptake ratio (LV/CS ratio) on 99mTc-DPD-scintigraphy were measured, while histological amyloid load was quantified as percentage of the analysed myocardial tissue using Sulfated Alcian Blue staining and the Fiji-ImageJ programme. Bivariate correlation and Pearson correlation coefficient were used to study the relationship between EMB and 99mTc-DPD-scintigraphy findings.

Results

We found a statistically significant correlation between histological amyloid load and Perugini score (r=0.47 p=0.02), as well as between Perugini score and LV/CS ratio (r=0.31 p=0.046). Mean LV tracer uptake showed a trend for correlation with histological amyloid load (r=0.37 p=0.08), without reaching statistical significance.

Conclusion

We found a correlation between the extent of histologic amyloid burden in EMB and the degree of cardiac tracer uptake on 99mTc-DPD-scintigraphy. Our results underline the reliability of 99mTc-DPD-scintigraphy as a surrogate of histological amyloid load in the diagnosis of cardiac ATTR amyloidosis. Possible implications for the assessment of prognosis are subject to future studies with a larger number of patients.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Pfizer

Glycaemic status and reperfusion injury in patients with ST-segment elevation myocardial infarction

Background

Failed myocardial tissue reperfusion due to microvascular injury despite successful culprit lesion percutaneous coronary intervention (PCI) is associated with poor clinical outcome in patients with ST-elevation myocardial infarction (STEMI). A possible influence of dysglycaemia on myocardial reperfusion injury is unclear.

Objectives

To investigate the association between glycaemic status and microvascular injury determined by magnetic resonance imaging in STEMI patients.

Methods

This prospective observational cohort study included 260 consecutive STEMI patients undergoing primary PCI between 2016 and 2019. Peripheral venous blood samples for glucose and HbA1c measurements were drawn on admission. Primary microvascular injury endpoint was defined as presence of intramyocardial haemorrhage (IMH) assessed by cardiac magnetic resonance T2* mapping at 4 (interquartile range [IQR]:2–5) days after PCI.

Results

HbA1c (odds ratio [OR]: 1.73 [95% CI: 1.24–2.40]; p=0.001), pre-diagnosis of diabetes (OR: 2.63 [95% CI: 1.18–5.90]; p=0.02) and glucose concentration (OR: 1.01 [95% CI: 1.00–1.01]; p=0.01) significantly predicted IMH, which was present in 90 (35%) patients. Of these three parameters, only HbA1c remained significantly associated with IMH (OR: 2.12 [95% CI: 1.12–3.99]; p=0.02) after adjusting for total ischemic time, culprit lesion location, pre- and post-interventional TIMI flow and peak biomarker concentrations (troponin, N-terminal pro-B-type natriuretic peptide and C-reactive protein). The rate of IMH was 24% in patients with HbA1c <5.7%, 43% in patients with HbA1c ≥5.7 to 6.4% and 59% in patients with HbA1c ≥6.5% (p<0.001).

Conclusions

In STEMI patients undergoing primary PCI, admission HbA1c was independently associated with reperfusion injury as determined by IMH. These findings suggest that IMH could represent the underlying pathophysiological link between dysglycaemia and adverse outcomes following STEMI.

Funding Acknowledgement

Type of funding sources: Public grant(s) – EU funding. Main funding source(s): FWF - Austrian Science Fund; ÖKG - Austrian Society of Cardiology Figure 1. This figure illustrates the relation between HbA1c and IMH by two patient examples successfully treated with PCI (intervention with stent implantation schematically shown on the very left side). The first patient (upper line), representing the patient group with HbA1c <5.7% (associated IMH risk 24%), showed an anterior wall STEMI without IMH (T2* mapping on the very right, corresponding schematic picture of the infarct area without IMH next on the left). The second patient (lower line), representing the patients with HbA1c ≥5.7% (associated IMH risk 47%), showed an anterior wall STEMI with large IMH (arrows point to the hypo-intense core on the T2* mapping image and to the corresponding dark-red area in the schematic illustration). The zoomed view of one microvessel indicates the complex pathophysiology of IMH (including endothelial destruction, embolisation of thrombotic material and inflammation). (Created with BioRender)

Cardio-pulmonary transit-time by cardiac magnetic resonance imaging: associates to infarct severity and adverse events after reperfused STEMI

Background

Cardiac magnetic resonance (CMR) data on cardiopulmonary-transit-time (cpTT) and its associates with infarct characteristics and clinical outcome after reperfused ST-elevation myocardial infarction (STEMI) are lacking so far.

Purpose

cpTT may serve as surrogate parameter for integrative cardiac performance and has been linked to heart failure.

Methods

A total of 207 patients (179 men [87%], median age 55 [interquartile range (IQR) 49–64] with acute STEMI underwent CMR on day 3 [IQR 2–4] and 4 months (m) [IQR 4–5] after primary percutaneous coronary intervention. cpTT was taken as the time between the peaks of time-intensity curves of gadolinium contrast to pass from the right ventricle (RV) to the left ventricle (LV). Infarct size, extent of microvascular obstruction (MVO), RV and LV dimensions and function were assessed at both occasions.

Results

cpTT decreased significantly between baseline and 4m CMR scan (8.6 seconds [IQR 7.5–9.6] to 7.8 sec [IQR 7–8.7], respectively, p<0.0001). Patients with presence of MVO had significantly prolonged cpTT at baseline and 4m follow-up (all p<0.022). According to Cox regression analysis (“functional model”) baseline cpTT (hazard ratio (HR) 1.5, 95% confidence interval (CI) 1.1–2.2; p=0.008) remained significantly associated to the occurrence of major adverse cardiac events (MACE) after adjustment for LV ejection fraction (EF) and cardiac index. According to Cox regression analysis (“tissue model”) baseline cpTT (HR 1.462, 95% CI 1.02–2.09, p=0.039) as well as extent of MVO (HR 1.196, 95% CI 1.081–1.324, p=0.001) remained significantly associated to MACE after adjustment for infarct size. Baseline cpTT (area under the curve [AUC]: 0.725, 95% confidence interval [CI] 0.57–0.88; p<0.009) was significantly higher for the prediction of MACE compared to LV ejection fraction (AUC: 0.686, 95% CI 0.51–0.87; p=0.031. AUC difference: 0.039, p<0.03). In Kaplan-Meier analysis, cpTT ≥9 sec was associated with clinical adverse cardiovascular events (p=0.008).

Conclusion

Following reperfused STEMI, cpTT predicts prognosis independently of infarct size and systolic function. Moreover, cpTT provides significantly higher prognostic implication in comparison with LV ejection fraction.

Funding Acknowledgement

Type of funding sources: None. cpTT over the cardiac cycle.Computation of cpTT in 2 STEMI patients.

Evolution of myocardial tissue injury over a decade after ST-elevation myocardial infarction: a cardiac magnetic resonance study

Background

In patients with first ST-elevation myocardial infarction (STEMI), the evolution of myocardial tissue injury parameters over a decade as assessed by cardiac magnetic resonance (CMR) has not yet been described.

Purpose

This study examined long-term myocardial tissue injury dynamics in STEMI patients treated with primary percutaneous coronary intervention (PCI), as well as its association with patient characteristics.

Methods

A total of 104 patients with STEMI were included in this observational study. Sequential late gadolinium enhanced CMR studies (after 3 days [interquartile ranges (IQR) 2–4], 4 months [IQR 4–5] and 9 years [IQR 8–10]) were conducted to assess left ventricular (LV) dimensions and function, infarct size and microvascular obstruction (MVO). T2* mapping was added at 9 year scan to assess the presence of persistent iron within the infarct core.

Results

Infarct size decreased progressively from 13% of LV myocardial mass [IQR 7–21] to 10.2% [IQR 5.2–16.1] to 8% [IQR 2.4–12.3] (p<0.001), with an average reduction rate of 6.4% ± 3.4 per year. Relative reduction of infarct size from baseline to 9y follow-up was 43% [IQR 18–66], 21% [IQR 3–42] during the first 4m and 33% [IQR 8–54] between 4m and 9y after STEMI. Decrease of infarct size was associated with greater baseline infarct size (p<0.004) and extent of MVO (p=0.01). MVO was present in 60% (60/104) of patients at baseline, but in none of the follow-up examinations. Sixteen patients had persistent iron within the infarct core at 9 year CMR. Clinical and imaging associates of persistent iron included younger age at study inclusion (p=0.036), higher peak hs troponin T (p<0.001), higher peak creatine kinase (p<0.001) and higher peak CRP (p=0.036) as well as greater infarct size at any occasion (all p<0.001) and greater MVO (p<0.001). Patients with persistent iron showed less relative infarct size regression (51% [IQR 41–79] versus 46% [IQR 32–54], p=0.009).

Conclusion

In patients with STEMI, the evolution of infarct size is a dynamic process that extends well beyond the first few months after the acute event. MVO vanishes in the first few weeks after the index event in all patients. However, persistence of iron within the infarct core occurs up to a decade after reperfused STEMI, reflecting its irreversibility and is associated with the initial infarct severity and worse infarct healing.

Funding Acknowledgement

Type of funding sources: None. Central Illustration.Evolution of STEMI over a decade.

Aortic stenosis reexpanded – a novel approach to determine aortic valve area with phase contrast cardiovascular magnetic resonance imaging

Background

Transthoracic echocardiography (TTE) has become the diagnostic standard for evaluating aortic stenosis (AS) severity, mainly because of its advantages in comparison to the gold standard of cardiac catheterization. However, its inaccuracies in determining stroke volume (SV) and consequentially computing aortic valve area (AVA) call for a more precise and dependable method. Phase contrast cardiovascular magnetic resonance imaging (PC-CMR) is an aspiring tool to push these boundaries.

Purpose

The aim of this study was to validate a novel and simple approach based on PC-CMR against the invasive and echocardiographic determination of SV and AVA in patients with moderate and severe AS.

Methods

A total of 50 patients with moderate or severe AS underwent TTE, cardiac catheterization and CMR; AVA by PC-CMR was determined via plotting momentary flow across the valve against momentary flow velocity. SV via CMR was measured directly via PC-CMR and volumetrically using cine images. Invasive SV and AVA were determined via Fick principle and Gorlin formula, respectively. TTE yielded SV and AVA using the continuity equation. Finally, gradients were calculated via the modified Bernoulli equation.

Results

SV by PC-CMR showed a strong correlation with cine-CMR with no significant bias (r: 0.730, p<0.001; SV by PC-CMR: 85±31ml; SV by cine-CMR: 85±19ml, p=0.829). Peak gradients determined by PC-CMR were 65±29mmHg and correlated inversely with AVA by PC-CMR (r: −0.371; p=0.008). Mean AVA during the whole systolic phase showed a moderate correlation (r: 0.544, p<0.001) to invasive AVA with a small bias (AVA by CMR: 0.78±0.25cm2 versus invasive AVA: 0.70±0.23cm2, bias: 0.08cm2, p=0.017). Inter-methodical correlation and bias of AVA as measured by TTE and invasive AVA (AVA by TTE: 0.81±0.23cm2, r: 0.580, p<0.001, bias 0.11cm2, p<0.001) were similar to AVA by PC-CMR and invasive AVA.

Conclusion

PC-CMR provides a great option to yield reliable and solid SV values in patients with moderate and severe AS. Furthermore, continuous determination of flow volumes and flow velocities is able to determine AVA in these patients in an easy and reproducible manner. Our novel approach shines a light on the diagnostic potential of PC-CMR for non-invasive AS grading, especially in cases where echocardiography reaches its limits and where clinical findings appear inconclusive.

Funding Acknowledgement

Type of funding sources: None. Central IllustrationCine (l,r) and PC-CMR (m) images in AS

Determinants and prognostic relevance of aortic stiffness in patients with recent ST-elevation myocardial infarction

Background

The association between aortic stiffness, cardiovascular risk factors and prognosis in patients with recent ST-elevation myocardial infarction (STEMI) is poorly understood. We analyzed the relationship between cardiovascular risk factors and arterial stiffening and assessed its prognostic significance in patients with recent STEMI.

Methods

We prospectively enrolled 408 consecutive patients who sustained a first STEMI and underwent primary percutaneous coronary intervention (PPCI). Aortic pulse wave velocity (PWV), a direct measure of aortic stiffness, was determined by the transit-time method using velocity-encoded, phase-contrast cardiac magnetic resonance imaging. Patient characteristics were acquired at baseline and major adverse cardiac and cerebrovascular events (MACCE) were assessed at 13 (interquartile range [IQR] 12–31) months. Cox regressionand logistic regression analysis were performed to explore predictors of PWV and MACCE.

Results

Median aortic PWV was 6.6 m/s (IQR 5.6–8.3m/s). In multivariable analysis, age (odds ratio [OR] 1.10, 95% confidence interval [CI], 1.08–1.14, p<0.001) and hypertension (OR 2.45, 95% CI, 1.53–3.91, p<0.001) were independently associated with increased PWV. Sex, diabetes, smoking status, dyslipidemia, and obesity were not significantly associated with PWV in adjusted analysis (all p>0.05). High PWV significantly and independently predicted occurrence of MACCE in adjusted analysis (hazard ratio [HR] 2.45, 95% CI 1.19–5.04, p=0.014).

Conclusion

In patients with recent STEMI, the impact of classical cardiovascular risk factors on aortic stiffness is mainly dependent on age and increased blood pressure. Increased aortic stiffness is associated with adverse clinical outcome post-STEMI, suggesting it as a relevant therapeutic target in this population.

Funding Acknowledgement

Type of funding sources: Public grant(s) – EU funding. Main funding source(s): Austrian Science Fund (FWF)Austrian Society of Cardiology Figure 1. Biorender.com

New quantitative automated model to simulate bacterial dissemination in human tissue during irrigation of contaminated wounds

This study presents a simple and cost-effective model using microparticles to simulate the bacterial distribution pattern in soft tissue after low- and high-pressure irrigation. Silica coated iron microparticles [comparable diameter (1 µm) and weight (0.8333 pg) to Staphylococcus aureus] were applied to the surface of twenty fresh human muscle tissue samples in two amputated lower legs. Particle dissemination into deep tissue layers as an undesired side effect was investigated in four measuring fields as positive control (PC) as well as after performing pulsatile high-pressure (HP, 8 measuring fields) and low-pressure flushing (LP, 8 measuring fields). Five biopsies were taken out of each measuring field to get a total number of 100 biopsies. After histological and digital image processing, the specimens were analysed, and all incomplete sections were excluded. A special detection algorithm was parameterised using the open source bioimage analysis software QuPath. The application of this detection algorithm enabled automated counting and detection of the particles with a sensitivity of 95 % compared to manual counts. Statistical analysis revealed significant differences (p < 0.05) in our three different sample groups: HP (M = 1608, S = 302), LP (M = 2176, SD = 609) and PC (M = 4011, SD = 686). While both HP and LP flushing techniques are able to reduce the number of bacteria, a higher effectiveness is shown for HP irrigation. Nevertheless, a challenge for the validity of the study is the use of dead tissue and therefore a possible negative influence of high-pressure irrigation on tissue healing and further dispersion of particles cannot be evaluated.

Invasive validation of a novel approach to determine aortic valve area with phase-contrast cardiac magnetic resonance imaging

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Austrian Society of Cardiology

Background. Echocardiography is considered the standard method for screening and diagnosing aortic valve stenosis. However, inaccuracies in the determination of stroke-volumes by the continuity equation might particularly make the evaluation of patients with low-flow states difficult. Phase-contrast cardiac magnetic resonance (PC-CMR) is a promising tool in overcoming these limitations by the simultaneous determination of flow volumes and velocities across the stenotic valve.

Purpose

The aim of this study is to validate a novel approach based on PC-CMR against the invasive determination of the aortic valve area (AVA).

Methods. PC-CMR was performed in 50 patients with moderate or severe AS (n = 52; age 72 years [interquartile range (IQR) 66 - 78], 38% of patients with low-flow states). All of them were referred to invasive evaluation of aortic stenosis by cardiac catheterization. Additionally, transthoracic echocardiography (TTE) was performed. Aortic valve area (AVA) was determined by PC-CMR (AVAPC-CMR) via plotting momentary flow across the valve against momentary flow velocity. AVAPC-CMR at different time points over the entire cardiac cycle was compared to invasively determined AVA, calculated according to the Gorlin-formula. Stroke volumes (SV) were determined by the Fick-principle, pressure gradients according to the modified Bernoulli-equation.

Results. Mean AVA during the whole systolic phase showed a good correlation (r: 0.544, p &lt; 0.001) with invasive AVA with a small bias (AVACMR: 0.78 cm², IQR: [0.60-0.96] versus AVAINVASIVE: 0.70 cm², IQR: [0.52-0.87], bias: 0.08 cm², p = 0.017). Intermethodical correlation and bias of AVA as measured by TTE (AVATTE) and AVAINVASIVE were similar to AVAPC-CMR (AVATTE: 0.81 cm²; IQR: [0.64-0.96] versus AVAINVASIVE: 0.70 cm², IQR: [0.52-0.87] r: 0.580, p &lt; 0.001, bias 0.11 cm², p &lt; 0.001). SV by PC-CMR showed a good correlation with Cine-CMR with no significant bias (r: 0.730, p &lt; 0.001; SVPC-CMR: 86 ± 31 ml; SVCine: 85 ± 19 ml). Maximum gradients determined by PC‑CMR were 65 ± 2 9mmHg and showed a good inverse correlation with AVAPC-CMR (r: ‑0.371; p = 0.008).

Conclusion. PC-CMR with continuous determination of flow volumes and flow velocities is able to determine AVA in patients with severe aortic stenosis with a tendency to overestimate AVA compared to invasively determined AVA.

Cardio-pulmonary transit-time by cardiac magnetic resonance imaging: associates to infarct severity and adverse events after reperfused STEMI

Funding Acknowledgements

Type of funding sources: None.

Background

Cardiac magnetic resonance (CMR) data on cpTT and its associates with infarct characteristics and clinical outcome after reperfused ST-elevation myocardial infarction (STEMI) are lacking so far.

Purpose

To investigate cardiopulmonary-transit-time (cpTT) and its value as surrogate parameter for integrative cardiac performance and its link to heart failure.

Methods

A total of 207 patients (179 men [87%], median age 55 [interquartile range (IQR) 49-64] with acute STEMI underwent CMR on day 3 [IQR 2-4] and 4 months (m) [IQR 4-5] after primary percutaneous coronary intervention. cpTT was taken as the time between the peaks of time-intensity curves of gadolinium contrast to pass from the right ventricle (RV) to the left ventricle (LV). Infarct size, extent of microvascular obstruction (MVO), RV and LV dimensions and function were assessed at both occasions.

Results

cpTT decreased significantly between baseline and 4m CMR scan (8.6 seconds [IQR 7.5-9.6] to 7.8 sec [IQR 7-8.7], respectively, p &lt; 0.0001). Patients with presence of MVO had significantly prolonged cpTT at baseline and 4m follow-up (all p &lt; 0.022). According to Cox regression analysis ("functional model") baseline cpTT (hazard ratio (HR) 1.5, 95% confidence interval (CI) 1.1–2.2; p= 0.008) remained significantly associated to the occurrence of major adverse cardiac events (MACE) after adjustment for LV ejection fraction (EF) and cardiac index. According to Cox regression analysis ("tissue model") baseline cpTT (HR 1.462, 95% CI 1.02–2.09, p= 0.039) as well as extent of MVO (HR 1.196, 95% CI 1.081–1.324, p= 0.001) remained significantly associated to MACE after adjustment for infarct size. Baseline cpTT (area under the curve [AUC]: 0.725, 95% confidence interval [CI] 0.57-0.88; p &lt; 0.009) was significantly higher for the prediction of MACE compared to LV ejection fraction (AUC: 0.686, 95% CI 0.51-0.87; p = 0.031. AUC difference: 0.039, p &lt; 0.03). In Kaplan-Meier analysis, cpTT ≥9 sec was associated with clinical adverse cardiovascular events (p = 0.008).

Conclusion

Following reperfused STEMI, cpTT predicts prognosis independently of infarct size and systolic function. Moreover, cpTT provides significantly higher prognostic implication in comparison with LV ejection fraction.

Evolution of myocardial tissue injury over a decade after ST-elevation myocardial infarction: a cardiac magnetic resonance study

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Austrian Society of Cardiology

Background

In patients with first ST-elevation myocardial infarction (STEMI), the evolution of myocardial tissue injury parameters over a decade as assessed by cardiac magnetic resonance (CMR) has not yet been described.

Purpose

This study examined long-term myocardial tissue injury dynamics in STEMI patients treated with primary percutaneous coronary intervention (PCI), as well as its association with patient characteristics.

Methods

A total of 104 patients with STEMI were included in this observational study. Sequential late gadolinium enhanced CMR studies (after 3 days [interquartile ranges (IQR) 2-4], 4 months [IQR 4-5] and 9 years [IQR 8-10]) were conducted to assess left ventricular (LV) dimensions and function, infarct size and microvascular obstruction (MVO). T2* mapping was added at 9 year scan to assess the presence of persistent iron within the infarct core.

Results

Infarct size decreased progressively from 13% of LV myocardial mass [IQR 7-21] to 10.2% [IQR 5.2-16.1] to 8% [IQR 2.4-12.3] (p &lt; 0.001), with an average reduction rate of 6.4% ± 3.4 per year. Relative reduction of infarct size from baseline to 9y follow-up was 43% [IQR 18-66], 21% [IQR 3-42] during the first 4m and 33% [IQR 8-54] between 4m and 9y after STEMI. Decrease of infarct size was associated with greater baseline infarct size (p &lt; 0.004) and extent of MVO (p = 0.01). MVO was present in 60% (60/104) of patients at baseline, but in none of the follow-up examinations. Sixteen patients had persistent iron within the infarct core at 9 year CMR. Clinical and imaging associates of persistent iron included younger age at study inclusion (p = 0.036), higher peak hs troponin T (p &lt; 0.001), higher peak creatine kinase (p &lt; 0.001) and higher peak CRP (p = 0.036) as well as greater infarct size at any occasion (all p &lt; 0.001) and greater MVO (p &lt; 0.001). Patients with persistent iron showed less relative infarct size regression (51% [IQR 41-79] versus 46% [IQR 32-54], p = 0.009).

Conclusion

In patients with STEMI, the evolution of infarct size is a dynamic process that extends well beyond the first few months after the acute event. MVO vanishes in the first few weeks after the index event in all patients. However, persistence of iron within the infarct core occurs up to a decade after reperfused STEMI, reflecting its irreversibility and is associated with the initial infarct severity and worse infarct healing.

Self-navigated 3D whole-heart MRA for non-enhanced surveillance of thoracic aortic dilation: a comparison to CTA

Funding Acknowledgements

Type of funding sources: None.

Background

The natural history of thoracic aortic aneurysm (TAA) is one of progressive expansion. Asymptomatic patients who do not meet criteria for repair require conservative management including ongoing aneurysm surveillance, mostly carried out by contrast-enhanced computed tomography angiography (CTA).

Purpose

To prospectively compare image quality and reliability of a prototype non-contrast, self-navigated 3D whole-heart magnetic resonance angiography (MRA) with contrast-enhanced computed tomography angiography (CTA) for sizing of thoracic aortic aneurysm (TAA).

Methods

Self-navigated 3D whole-heart 1.5 T MRA was performed in 20 patients (aged 67 ± 8.6 years, 75% male) for sizing of TAA; a subgroup of 18 (90%) patients underwent additional contrast-enhanced CTA on the same day. Subjective image quality was scored according to a 4-point Likert scale and ratings between observers were compared by Cohen’s Kappa statistics. Continuous MRA and CTA measurements were analyzed with regression and Bland-Altman analysis.

Results

Overall subjective image quality as rated by two observers was 1 [interquartile range (IQR) 1-2] for self-navigated MRA and 1.5 [IQR 1-2] for CTA (p = 0.717). For MRA a perfect inter-observer agreement was found for presence of artefacts and subjective image sharpness (κ=1). Subjective signal inhomogeneity correlated highly with objectively quantified inhomogeneity of the blood pool signal (r = 0.78-0.824, all p &lt;0.0001). Maximum diameters of TAA as measured by self-navigated MRA and CTA showed excellent correlation (r = 0.997, p &lt; 0.0001) without significant inter-method bias (bias -0.0278, lower and upper limit of agreement -0.74 and 0.68, p = 0.749). Inter- and intraobserver correlation of aortic aneurysm as measured by MRA was excellent (r = 0.963 and 0.967, respectively) without significant bias (all p ≤ 0.05).

Conclusion

Self-navigated 3D whole-heart MRA enables reliable contrast- and radiation free aortic dilation surveillance without significant difference to standardized CTA while providing predictable acquisition time and by offering excellent image quality.

Abstract Figure.

Validation of a simple ECG score for infarct size estimation in patients with first-time ST-elevation myocardial infarction

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Austrian Science Fund

Background

The magnitude of myocardial damage after acute ST-elevation myocardial infarction (STEMI) is a crucial prognostic determinant. Cardiac magnetic resonance (CMR) imaging offers a precise infarct severity assessment after STEMI; however, limited to restricted availability in daily clinical routine. Recently, a simple ECG score (DETERMINE score) was developed for infarct size (IS) estimation in STEMI patients with prior infarction. We sought to validate this score in patients with first-time STEMI for the assessment of myocardial injury visualized by CMR.

Methods

In this validation study, 423 revascularized first-time STEMI patients (median age 56, 17% women) were included. ECG was conducted at discharge for evaluation of the DETERMINE and Selvester score. CMR imaging was performed at a median of 3 days for the assessment of infarct characteristics (IS and microvascular obstruction [MVO]).

Results

Median DETERMINE score of the overall cohort was 8 points (interquartile range: 5-11). Patients presenting with a score &gt; 8 points had more often anterior infarct localization (64% vs. 29%, p &lt; 0.001) and higher peak hs-TnT levels (6957 ng/l vs. 3117 ng/l, p &lt; 0.001). In linear and binary multivariable logistic regression analysis, the DETERMINE score remained as independent associate of IS (odds ratio [OR]: 1.09, 95% confidence interval [CI] 1.00 to 1.18, p = 0.047) and MVO (OR: 1.09, 95% CI 1.02 to 1.16, p = 0.016), after adjustment for Selvester score and peak hs-cTnT.

Conclusions

In survivors of first-time STEMI, the DETERMINE score provides an easy and inexpensive tool for suitable IS estimation. Moreover, the DETERMINE score showed significant and independent association with MVO. Thus, this simple ECG score might help identify patients at high risk of large infarct burden who might benefit from more aggressive treatment strategies.

Cardiac magnetic resonance derived global longitudinal strain outperforms established functional parameters in prognostication after ST-elevation myocardial infarction

Funding Acknowledgements

Type of funding sources: None.

Background

Although left ventricular ejection fraction (LVEF) is recommended for left ventricular (LV) systolic function assessment and risk stratification of patients with ST-elevation myocardial infarction (STEMI), its prognostic value is limited. Other measures of LV function such as global longitudinal strain (GLS) and mitral annular plane systolic excursion (MAPSE) might provide additional prognostic information post-STEMI. However, comprehensive investigations comparing these parameters in terms of prediction of hard clinical events following STEMI are lacking so far.

Purpose

We aimed to investigate the comparative prognostic value of LVEF, MAPSE and GLS by cardiac magnetic resonance (CMR) imaging in acute STEMI patients.

Methods

This observational study included 407 consecutive acute STEMI patients treated with primary percutaneous coronary intervention (PCI). Comprehensive CMR investigations were performed 3 [interquartile range (IQR): 2-4] days after PCI to determine LVEF, GLS and MAPSE as well as myocardial infarct characteristics. Primary endpoint was the occurrence of MACE defined as composite of death, re-infarction and congestive heart failure.

Results

During a follow-up of 21 [IQR: 12-50] months, 40 (10%) patients experienced MACE. Patients with MACE showed significantly lower LVEF (49% vs. 53%, p = 0.005) and MAPSE (7.9 mm vs. 9.1 mm, p = 0.001), as well as higher GLS values (-10.2% vs. -12.3 %, p &lt; 0.001). GLS showed the highest prognostic value with an area under the curve (AUC) of 0.71 (95% CI 0.63-0.79; p &lt; 0.001) compared to MAPSE (AUC: 0.67, 95% CI 0.58-0.75; p = 0.001) and LVEF (AUC: 0.64, 95% CI 0.54-0.73; p = 0.005). After multivariable analysis, GLS emerged as independent predictor of MACE (HR: 1.22, 95% CI 1.11-1.35; p &lt; 0.001). Of note, GLS remained associated with MACE (p &lt; 0.001) even after adjustment for infarct size and microvascular obstruction.

Conclusion

CMR-derived GLS emerged as strong and independent predictor of MACE after acute STEMI with additive prognostic validity to LVEF and parameters of myocardial damage.

Self-navigated versus navigator-gated 3D MRI sequence for non-enhanced aortic root measurement in transcatheter aortic valve intervention

Funding Acknowledgements

Type of funding sources: None.

Background

Preprocedural transcatheter aortic valve intervention (TAVI) evaluation requires reliable aortic root measurements for correct valve sizing.

Purpose

To prospectively compare image-quality, reliability and graft sizing of a prototype self-navigated and a navigator-gated non-contrast three dimensional (3D) whole-heart magnetic-resonance-angiography (MRA) sequence with computed-tomography-angiography (CTA) for planning transcatheter-aortic-valve-intervention (TAVI).

Methods

Self- and navigator-gated 1.5T MRA were performed in 27 patients (aged 83 ± 5 years, 41% male) for aortic root sizing and coronary ostia height measurements; 15 (56%) patients underwent additional CTA. Subjective-image quality was graded on a 4-point Likert scale, objective MRA image-quality was assessed by signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR). Continuous MRA and CTA measurements were analyzed with regression and Bland-Altman analysis, valve sizing by kappa statistics.

Results

Median image-quality as rated by two observers was 1.5 [interquartile range (IQR) 1-3] for self-navigated MRA and 1 [IQR 1-2] for navigator-gated MRA (p = 0.059). SNR and CNR were comparable between MRA sequences (p = 0.471 and 0.445, respectively). Acquisition time was shorter for self-navigated MRA compared to navigator-gated MRA (5.5 ± 1 minutes vs, 6.5 ± 2 minutes, p = 0.029).  Inter-observer correlation of aortic root measurements was high to very high for both self- and navigator-gated MRA (r = 0.75 to 0.94 and r = 0.85 to 0.96, respectively, all p &lt; 0.0001). Theoretical prosthetic valve sizing of self-navigated MRA and CTA was equivalent (κ=1). However, in four patients (15%) one coronary ostium each (right coronary artery 3, left main artery 1) was not clearly definable on self-navigated MRA.

Conclusion

Self-navigated MRA enables aortic annulus TAVI measurements without significant difference to navigator-gated MRA at shortened acquisition time. Prosthesis sizing by self-navigated MRA measurements is equivalent to navigator-gated MRA and CTA-based choice.

Abstract Figure.

Determinants and prognostic relevance of aortic stiffness in patients with recent ST-elevation myocardial infarction

Funding Acknowledgements

Type of funding sources: None.

Background

The association between aortic stiffness, cardiovascular risk factors and prognosis in patients with recent ST-elevation myocardial infarction (STEMI) is poorly understood.

Purpose

We analyzed the relationship between cardiovascular risk factors and arterial stiffening and assessed its prognostic significance in patients with recent STEMI.

Methods

We prospectively enrolled 408 consecutive patients who sustained a first STEMI and underwent primary percutaneous coronary intervention (pPCI). Aortic pulse wave velocity (PWV), a direct measure of aortic stiffness, was determined by the transit-time method using velocity-encoded, phase-contrast cardiac magnetic resonance imaging. Patient characteristics were acquired at baseline and major adverse cardiac and cerebrovascular events (MACCE) were assessed at 13 (interquartile range [IQR] 12–31) months. Cox regression- and logistic regression analysis were performed to explore predictors of PWV and MACCE.

Results

Median aortic PWV was 6.6 m/s (IQR 5.6–8.3m/s). In multivariable analysis, age (odds ratio [OR] 1.10, 95% confidence interval [CI], 1.08–1.14, p &lt; 0.001) and hypertension (OR 2.45, 95% CI, 1.53–3.91, p &lt; 0.001) were independently associated with higher PWV. Gender, diabetes, smoking status, dyslipidemia, and obesity were not significantly associated with PWV in adjusted analysis (all p &gt; 0.05). High PWV significantly and independently predicted occurrence of MACCE in adjusted analysis (hazard ratio [HR] 2.45, 95% CI 1.19–5.04, p = 0.014).

Conclusion

In patients with recent STEMI, the impact of classical cardiovascular risk factors on aortic stiffness is mainly dependent on age and increased blood pressure. Increased aortic stiffness is associated with adverse clinical outcome, suggesting it as a relevant therapeutic target in this population.

[Cardiac magnetic resonance imaging : Trends and developments]

Hintergrund

Durch die Entwicklung robuster Techniken und deren umfassender Validierung hat sich die kardiale Magnetresonanztomographie (CMR) in ihrem knapp 25-jährigen klinischen Einsatz ein breites Indikationsspektrum erarbeitet. Die Erfassung kardialer Volumina und systolischer Ventrikelfunktion sowie die Charakterisierung fokaler Myokardnarben sind heute Teil der CMR-Standard-Bildgebung. Zuletzt haben die Einführung beschleunigter Bildakquisitionstechnologien, die neuen Bildgebungsmethoden des myokardialen T1- und T2-Mappings und der 4‑D-Flussmessungen sowie die neue Postprocessing-Technik des myokardialen Feature-Trackings an Relevanz gewonnen.

Methode

Diese Überblicksarbeit basiert auf einer umfassenden Literaturrecherche in der PubMed-Datenbank zu neuen CMR-Techniken und ihrer klinischen Anwendung.

Ergebnisse und Schlussfolgerung

Dieser Artikel zeigt eine Übersicht über die neuesten technischen Entwicklungen im Bereich der CMR sowie deren Anwendungsmöglichkeiten anhand der wichtigsten klinischen Fragestellungen.

High sensitivity C-reactive protein is associated with worse infarct healing after revascularized ST-elevation myocardial infarction

Background

The inflammatory response due to myocardial tissue injury in the setting of acute ST-elevation myocardial infarction (STEMI) is essential for proper local infarct healing. However, an excessive inflammatory response may aggravate myocardial damage and hampers infarct healing processes. The present study aimed to investigate the association of systemic inflammatory biomarkers with infarct size (IS) dynamics post-STEMI, using cardiac magnetic resonance (CMR) imaging.

Methods

This prospective observational study included 245 STEMI patients treated with primary percutaneous coronary intervention (pPCI). Peak values of high-sensitivity C-reactive protein (hs-CRP), white blood cell count (WBCc) and fibrinogen were determined serially until 96 hours after pPCI. Infarct healing, defined as relative IS reduction from baseline to 4 months after STEMI, was assessed using late gadolinium enhanced CMR imaging.

Results

IS significantly decreased from 16% of left ventricular mass (LVM) (Interquartile range [IQR]:8–24) at baseline to 10% (IQR:5–17) at 4 months (p&lt;0.001). Relative IS reduction was 35% (IQR:8–50). Whereas peak WBCc (p=0.926) and peak fibrinogen (p=0.161) were not significantly associated with relative IS reduction, peak hs-CRP showed a significant association with IS reduction (p=0.003). In multivariable logistic regression analysis, the association between peak hs-CRP and relative IS reduction remained significant after adjustment for baseline IS, hypertension, hs-cardiac troponin T and N-terminal pro B-type natriuretic peptide (odds ratio:0.35 [95% confidence interval:0.19–0.63]; p=0.001).

Conclusions

In STEMI patients treated with pPCI, hs-CRP was independently associated with 4 months IS reduction as determined by CMR, suggesting a pathophysiological interplay between inflammation and adverse infarct healing in survivors of acute STEMI.

Funding Acknowledgement

Type of funding source: Private grant(s) and/or Sponsorship. Main funding source(s): Austrian Society of Cardiology

Influence of myocardial damage on serum procalcitonin in ST-elevation myocardial infarction

Background

Myocardial tissue injury due to acute ST-elevation myocardial infarction (STEMI) initiates an inflammatory response with a release of systemic inflammatory biomarkers including C-reactive protein (CRP) and white blood cell count (WBCc), which, however, hampers the usefulness of these routine biomarkers to identify concomitant infections. The clinical role of Procalcitonin (PCT), a promising marker of bacterial infections, to detect concomitant infections in acute STEMI is unknown, mainly because it is unclear whether myocardial injury per se induces a systemic PCT release.

Purpose

To investigate release kinetics of serum PCT in the acute setting of STEMI and possible associations with myocardial injury markers as comprehensively assessed by cardiac magnetic resonance (CMR) imaging.

Methods

In this prospective observational study, we included 141 STEMI patients treated with primary percutaneous coronary intervention (PCI). Concentrations of PCT, high-sensitivity CRP (hs-CRP), WBCc and high-sensitivity cardiac troponin T (hs-cTnT) were measured serially at day 1 and day 2 after infarction. CMR imaging to assess infarct size (IS), extent of microvascular injury (MVI) and occurrence of intramyocardial haemorrhage (IMH) was performed within the first week following STEMI.

Results

Median concentrations of PCT were 0.07μg/l at both time points. In 140 patients (99%), both PCT values were within the normal range (≤0.5μg/l). Whereas hs-CRP, WBCc, and hs-TnT were significantly correlated with CMR markers of myocardial damage, PCT did not show significant correlations (all p&gt;0.10) with IS (PCT24h: r=0.07; PCT48h: r=0.13) or MVI (PCT24h: r=−0.03; PCT48h: r=0.09). Furthermore, PCT failed to discriminate between large and small IS or MVI or between presence and absence of IMH (AUC values:0.46–0.55).

Conclusions

In the acute phase after PCI for STEMI, circulating PCT remained unaffected by the extent of myocardial and microvascular tissue damage as visualized by CMR imaging. These data highlight the clinical potential of PCT to identify concomitant infections and to guide antibiotic treatments in STEMI patients.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): Austrian Science Fund, Tiroler Wissenschaftsförderung

Self-navigated MRI 3D whole heart sequence for non-enhanced aortic root measurement in transcatheter aortic valve intervention: comparison to cardiac CT

Purpose

To evaluate image quality, inter-observer reliability and diagnostic accuracy of self-navigated noncontrast 3D whole-heart magnetic resonance angiography (MRA) for transcatheter aortic valve intervention (TAVI) evaluation in comparison to standardized contrast-enhanced computed tomography angiography (CTA).

Methods

Whole-heart 1.5 T MRA was performed in 33 patients (aged 84 years [IQR 79–86], 48% male) for aortic root sizing and measurements of coronary ostia heights. A subgroup of 18 (55%) patients underwent additional CTA as gold standard for TAVI measurements. Image quality was assessed by a 4-point Likert scale, continuous MRA and CTA measurements were compared with regression and Bland-Altman analysis, valve sizing by kappa statistics.

Results

Median image quality of MRA as rated by two observers according was 1.5 [IQR 1.5–2.5]. In 4 patients (12%) one coronary ostium each (right coronary artery 3, left main artery 1) was not clearly definable on MRA. Inter-observer correlation was substantial to excellent (r=0.61 to 0.92) with a bias of 19 mm2 for annulus area (lower limit of agreement −59 mm2, upper limit of agreement 98 mm2; p=0.009). Aortic root and ostia height measurements by MRA and CTA showed substantial to excellent correlation (r=0.65 to 0.90) with no significant bias (all p≥0.333). Mean annulus area for MRA was 414±71 mm2 and for CTA 422±80 mm2 (r=0.9) with a bias of −8 mm2 (lower limit of agreement −79 mm2, upper limit of agreement −62 mm2; p=0.333). Regarding prosthetic valve sizing there was complete consistency between MRA and CTA-based decisions (κ=1).

Conclusion

Self-navigated noncontrast 3D whole-heart MRA enables reliable aortic root TAVI measurements without significant difference to standardized CTA. Prosthesis sizing by MRA measurements would completely match to CTA-based choice. However, in some cases coronary ostia may be difficult to define.

Funding Acknowledgement

Type of funding source: None

Cardiac magnetic resonance derived global longitudinal strain outperfoms established functional parameters in prognostication after ST-elevation myocardial infarction

Background

Left ventricular ejection fraction (LVEF) is the parameter of choice for left ventricular (LV) function assessment and risk stratification of patients with ST-elevation myocardial infarction (STEMI); however, its prognostic value is limited. Other measures of LV function such as global longitudinal strain (GLS) and mitral annular plane systolic excursion (MAPSE) might provide additional prognostic information post-STEMI. However, comprehensive investigations comparing these parameters in terms of prediction of hard clinical events following STEMI are lacking so far.

Purpose

We aimed to investigate the comparative prognostic value of LVEF, MAPSE and GLS by cardiac magnetic resonance (CMR) imaging in the acute stage post-STEMI for the occurrence of major adverse cardiac events (MACE).

Methods

This observational study included 407 consecutive acute STEMI patients treated with primary percutaneous coronary intervention (PCI). Comprehensive CMR investigations were performed 3 [interquartile range (IQR): 2–4] days after PCI to determine LVEF, GLS and MAPSE as well as myocardial infarct characteristics. Primary endpoint was the occurrence of MACE defined as composite of death, re-infarction and congestive heart failure.

Results

During a follow-up of 21 [IQR: 12–50] months, 40 (10%) patients experienced MACE. LVEF (p=0.005), MAPSE (p=0.001) and GLS (p&lt;0.001) were significantly related to MACE. GLS showed the highest prognostic value with an area under the curve (AUC) of 0.71 (95% CI 0.63–0.79; p&lt;0.001) compared to MAPSE (AUC: 0.67, 95% CI 0.58–0.75; p=0.001) and LVEF (AUC: 0.64, 95% CI 0.54–0.73; p=0.005). After multivariable analysis, GLS emerged as sole independent predictor of MACE (HR: 1.22, 95% CI 1.11–1.35; p&lt;0.001). Of note, GLS remained associated with MACE (p&lt;0.001) even after adjustment for infarct size and microvascular obstruction.

Conclusion

CMR-derived GLS emerged as strong and independent predictor of MACE after acute STEMI with additive prognostic validity to LVEF and parameters of myocardial damage.

Funding Acknowledgement

Type of funding source: None

Clinical risk score for prediction of early left ventricular thrombus after percutaneous coronary intervention for ST-elevation myocardial infarction

Background

Cardiac magnetic resonance (CMR) is the reference standard for left ventricular (LV) thrombus detection in patients with acute ST-elevation myocardial infarction (STEMI). However, routine CMR imaging is currently not recommended post-STEMI.

Objective

This observational study sought to develop a practical risk score for the prediction of early LV thrombus formation after STEMI to identify patients in whom routine CMR might be appropriate.

Methods and results

Five hundred and fifty-six consecutive patients underwent transthoracic echocardiography (TTE) and CMR at 3 [IQR: 2–4] days after primary percutaneous coronary intervention (PCI) for acute STEMI. A LV thrombus was visualized in 12 patients (2.2%) using TTE and in 22 patients (4%) using CMR. A weighted risk score including multivariable associates of LV thrombus formation (LV ejection fraction by TTE, peak high-sensitivity cardiac troponin T and peak high-sensitivity C-reactive protein) and left anterior descending coronary artery as culprit vessel, with a range of 0 to 7 points (median risk score: 2 points) showed a strong and significantly higher area under the curve (0.93 (95% CI 0.88–0.97; p&lt;0.001)) for LV thrombus prediction than each individual risk factor alone (p&lt;0.001). The sensitivity and the specificity of the risk score was 91% and 80%, respectively. The incidence of LV thrombi was 0% in the very low risk group (0 to 1 points, n=248), 1.8% in the low risk group (2 to 4 points, n=219) and 20.2% in the high risk group (5 to 7 points, n=89). Eighty-two percent of all LV thrombi occurred in the high risk group (number needed to scan to detect one LV thrombus=5).

Conclusions

The proposed risk score provides incremental value for the prediction of early LV thrombus and could be useful to identify STEMI patients in whom routine CMR for LV thrombus evaluation could be most meaningful. Additional investigation is warranted to validate the clinical application of the score.

Funding Acknowledgement

Type of funding source: None

P3095Left ventricular thrombus formation after ST-elevation myocardial infarction: a prospective observational CMR study

Background

Left ventricular (LV) thrombus formation is a severe complication after acute ST-segment elevation myocardial infarction (STEMI). The incidence and determinants of LV thrombus formation are still a matter of controversy.

Purpose

We aimed to assess the incidence as detected by cardiac magnetic resonance (CMR) imaging as well as the determinants of LV thrombus formation in contemporary reperfused STEMI patients.

Methods

This prospective observational study included 530 consecutive STEMI patients treated with primary percutaneous coronary intervention (PCI). Comprehensive CMR was performed at a median of 3 days (interquartile range 2–4 days) after symptom onset for the evaluation of LV thrombus formation as well as LV function and infarct severity.

Results

LV thrombi were detected in 17 patients (3.2% of the overall cohort). The incidence of LV thrombi in anterior STEMI patients (n=247) was 6.9%. In all patients presenting with LV thrombus left anterior descending artery (LAD) was identified as culprit lesion. The occurrence of thrombi was significantly associated with reduced LV ejection fraction (LVEF) (p<0.001), larger LV end-diastolic volume (p<0.001) and LV end-systolic volume (p<0.001), larger areas of microvascular obstruction (MVO) (p=0.003) and larger infarct size (IS) (p<0.001). Furthermore, increased levels of peak high sensitivity cardiac Troponin T (p<0.001) and hyperlipidaemia (p=0.038) were significantly related to LV thrombi. In multivariable analysis including IS, LVEF and MVO, only LVEF (odds ratio: 0.91 (95% confidence interval: 0.87–0.96); p=0.001) emerged as independent predictor of LV thrombus formation.

Conclusion

The risk of LV thrombus formation remains considerable in contemporary treated STEMI patients, especially in those with LAD as culprit lesion. Among CMR parameters of LV dysfunction and infarct severity, only baseline LVEF, but not IS or MVO, independently predicted LV thrombus formation after STEMI.

4937Global longitudinal strain by feature tracking predicts adverse remodeling in ST-elevation myocardial infarction incremental to

Objectives

To evaluate the independent and incremental value of left ventricular (LV) strain assessed by cardiac magnetic resonance feature tracking (CMR-FT) for prediction of adverse LV remodeling following ST-elevation myocardial infarction (STEMI).

Background

The role of LV myocardial strain by CMR-FT for prediction of adverse remodeling after STEMI in comparison to LV ejection fraction and infarct severity is unclear.

Methods

STEMI patients treated with primary percutaneous coronary intervention within 24 hours after symptom onset were enrolled. CMR core laboratory analysis was performed to assess LV ejection fraction, infarct pathology and LV myocardial strain. The primary endpoint was adverse remodeling defined as ≥20% increase in LV end-diastolic volume from baseline to 4 months.

Results

From the 232 patients included, 38 (16.4%) reached the primary endpoint. Global longitudinal strain (GLS), global radial strain, and global circumferential strain were all predictive of adverse remodeling (p<0.01 for all), but among strain values only GLS was an independent predictor of adverse remodeling (hazard ratio: 1.36 [1.03–1.78]; p=0.028) after adjustment for strain parameters, ejection fraction and CMR markers of infarct severity. A GLS >-14% was associated with a 4-fold increase in risk for LV remodeling (hazard ratio: 4.16 [1.56–11.13]; p=0.005). Addition of GLS to a baseline model comprising ejection fraction, infarct size and microvascular obstruction resulted in net reclassification improvement of 0.26 ([0.13–0.38]; p<0.001) and integrated discrimination improvement of 0.02 ([0.01–0.03]; p=0.006).

Conclusions

In STEMI survivors, determination of GLS using CMR-FT provides important prognostic information for the development of adverse remodeling that is incremental to LV ejection fraction and CMR markers of infarct severity.

P2714Time-dependent myocardial necrosis in patients suffering from ST-elevation myocardial infarction without angiographic collateral flow visualized by cardiac magnetic resonance imaging

Background

Acute complete occlusion of a coronary artery results in progressive ischemia, moving from the endocardium to the epicardium (“wavefront”). Dependent on time-to-reperfusion and collateral flow, myocardial infarction (MI) will manifest, with transmural MI portending poor prognosis. Late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) imaging can detect MI with high diagnostic accuracy. Primary percutaneous coronary intervention (PCI) is the preferred reperfusion strategy in patients with STEMI <12 hours of symptom onset.

Purpose

We sought to visualize time-dependent necrosis in a ST-segment elevation myocardial infarction (STEMI) population by LGE-CMR.

Methods

STEMI patients with: single-vessel disease, complete occlusion with Thrombolysis in Myocardial Infarction (TIMI) score 0, absence of collateral flow (Rentrop score 0) and symptom onset <12 hours were consecutively enrolled. By LGE-CMR, area at risk (AAR) and infarct size (IS), myocardial salvage index (MSI), transmurality index, and transmurality grade (0–50%, 51–75%, 76–100%) were determined.

Results

164 patients (54±11 years, 80% male) were included. Receiver-operating-characteristic (ROC)-curve (area under the curve [AUC] = 0.81) indicating transmural necrosis revealed the best diagnostic cut-off for a symptom-to-balloon time of 121 minutes, i.e. patients with >121 minutes demonstrated increased IS, transmurality index, transmurality grade (all p-values <0.01), and decreased MSI (p<0.001) vs. patients with symptom-to-balloon times ≤121 minutes.

Conclusions

In myocardial infarction with no residual antegrade, and no collateral flow, immediate reperfusion is vital. A symptom-to-balloon time of >121 minutes causes a high grade of transmural necrosis. In the present, pure STEMI population, time to reperfusion to salvage myocardium was less than suggested by current guidelines.

Extending Statistical Boosting

Background: Boosting algorithms to simultaneously estimate and select predictor effects in statistical models have gained substantial interest during the last decade.

Objectives: This review highlights recent methodological developments regarding boosting algorithms for statistical modelling especially focusing on topics relevant for biomedical research.

Methods: We suggest a unified framework for gradient boosting and likelihood-based boosting (statistical boosting) which have been addressed separately in the literature up to now.

Results: The methodological developments on statistical boosting during the last ten years can be grouped into three different lines of research: i) efforts to ensure variable selection leading to sparser models, ii) developments regarding different types of predictor effects and how to choose them, iii) approaches to extend the statistical boosting framework to new regression settings.

Conclusions: Statistical boosting algorithms have been adapted to carry out unbiased variable selection and automated model choice during the fitting process and can nowadays be applied in almost any regression setting in combination with a large amount of different types of predictor effects.

Cross-sectional point prevalence survey to study the environmental contamination of nosocomial pathogens in intensive care units under real-life conditions

BACKGROUND

In intensive care units (ICUs), inanimate surfaces and equipment may be contaminated by nosocomial pathogens, including multi-drug-resistant micro-organisms.

AIMS

To assess the degree of environmental contamination close to and distant from patients, and contamination of healthcare workers' (HCWs) hands with nosocomial pathogens under real-life conditions and to investigate potential transmission events.

METHODS

Over the course of three weeks, agar contact samples were taken close to and distant from patient areas and from HCWs' hands in eight ICUs of a tertiary care hospital in Innsbruck, Austria. Each ICU was visited once without announcement. Species identification and antimicrobial susceptibility testing were performed according to standard methods, and corresponding strains from patient, environment and hand samples were genotyped using pulsed-field gel electrophoresis.

FINDINGS

Among 523 samples, HCWs' hands were most frequently contaminated with potentially pathogenic bacteria (15.2%), followed by areas close to patients (10.9%) and areas distant from patients (9.1%). Gram-positive bacteria were identified most often (67.8%), with Enterococcus spp. being the most prevalent species (70% vancomycin sensitive and 30% vancomycin resistant) followed by Staphylococcus aureus, of which 64% were classified as meticillin-resistant Staphylococcus aureus. Molecular typing documented identical strains among patient, environment and hand isolates.

CONCLUSION

This study found widespread contamination of the ICU environment with clinically relevant pathogens, including multi-drug-resistant micro-organisms, despite cleaning and disinfection. The bioburden might not be restricted to areas close to patients. The role of extended environmental disinfection of areas distant from patients in order to improve infection prevention needs further discussion.

Self-disinfecting surfaces and activity against Staphyloccocus aureus ATCC 6538 under real-life conditions

Environmental surface contamination provides a potential reservoir for pathogens to cause infections. As such, self-disinfecting surfaces have been developed to possibly reduce exogenous transmission. Five different self-disinfecting surfaces were evaluated for activity against Staphylococcus aureus ATCC 6538 under real-life conditions using the dry inoculation method. Various antimicrobial effects were detected. However, following disinfection with alcoholic wipes, these effects disappeared. Further development is necessary to produce self-disinfecting surfaces that are stable in the presence of hospital disinfectants, as it is impossible to guarantee that self-disinfecting surfaces in healthcare settings will not be exposed to disinfectants.

Myocardial edema in acute myocarditis: relationship of T2 relaxometry and late enhancement burden by using dual-contrast turbo spin-echo MRI

To quantify myocardial edema by using a T2 relaxometry approach with a dual-contrast turbo spin-echo (dcTSE) sequence in patients with acute myocarditis regarding focal late gadolinium enhancement (LGE) burden. CMR T2 relaxometry was performed in 39 patients (age 41 ± 19 years; 36% women) with LGE in a typical myocarditis pattern and in ten healthy volunteers (age 46 ± 12; 60% woman). dcTSE sequence (echo time 29 and 75 ms, respectively) was used for T2 mapping, analysis were performed on the basis of region of interest (ROI). Myocardial T2 relaxation times (T2 RT) in patients-ROI with focal LGE were significantly (p < 0.001) higher than T2 RT in patients-ROI without apparent LGE pattern (65 ms (IQR 36-95) vs. 60 ms (IQR 26-88), respectively). T2 RT in healthy volunteers [55 ms (IQR 35-71)] were significantly lower than in patients ROI with or without focal LGE-pattern (p < 0.001, respectively). T2 RT assessed by dcTSE are significantly higher in patients segments with and without focal LGE compared to normal controls, supporting a global myocardial inflammatory process in acute myocarditis. Furthermore, this quantitative T2-mapping approach highlights the potential to identify patients with diffuse myocarditis.

Sonographic Weight Estimation in Small-for-Gestational-Age Fetuses

PURPOSE

To determine the accuracy of sonographic weight estimation (WE) for small-for-gestational-age (SGA) fetuses, and to further differentiate the evaluation between symmetric and asymmetric SGA fetuses.

MATERIALS AND METHODS

The accuracy of WE in SGA fetuses (n = 898) was evaluated using 14 sonographic models and was further differentiated between symmetric (n = 750) and asymmetric (n = 148) SGA fetuses. SGA fetuses were considered to be asymmetric with a head circumference to abdominal circumference ratio above the 95th percentile. The accuracy of the different formulas was compared using means of percentage errors (MPE), medians of absolute percentage errors (MAPE), and proportions of estimates within 10 % of actual birth weight.

RESULTS

RESULTS for the subgroup of asymmetric SGA fetuses differed significantly from the subgroup of symmetric SGA fetuses. MPE values were closer to zero with most of the formulas in the asymmetric SGA group. Apart from the Siemer, Shepard, Merz and Warsof equations, all formulas showed an underestimation of fetal weight in asymmetric SGA fetuses. In contrast, in the symmetric SGA group, all of the formulas commonly used for fetuses in a normal weight range showed a systematic overestimation of fetal weight. Overall the best accuracy was achieved by using the Sabbagha equation (MPE 1.7 %; SD 9.0 %; MAPE: 6.0).

CONCLUSION

An accurate WE in SGA fetuses is feasible using the Sabbagha formula. However, one has to be aware of the significant differences in WE between symmetric and asymmetric SGA fetuses.

A New Sonographic Weight Estimation Formula for Fetuses with Congenital Diaphragmatic Hernia

PURPOSE

The accuracy of the sonographic weight estimation (WE) of fetuses with congenital diaphragmatic hernia (CDH) is significantly lower than that of fetuses without any malformations. The objective of this study was to develop and evaluate the first specific sonographic weight formula for fetuses with CDH.

MATERIALS AND METHODS

In a retrospective, multicenter, cohort study, a statistical estimation technique known as "multivariable fractional polynomial regression" was applied to a group of 146 fetuses with CDH. Each fetus underwent an ultrasound examination with complete biometric parameters within 7 days of delivery. A new formula was derived using the obtained data and was then compared with other commonly used equations. The accuracy of the different formulas was compared using means of signed percentage errors (SPE), medians of absolute percentage errors (MAPE), and fractions of estimates within prespecified error bounds.

RESULTS

The new derived formula is: EFW = 10^(4.6729 107 371 + 0.2365 011 768 * HC + 0.2228 897 682 * FL^2 - 0.0129 895 773 * FL^3 - 1.0470 039 072 * (FL * HC)^0.5 + 0.0004 314 661 * (AC * HC) - [in case of liver herniation] 0.0062 112 122), where EFW is the estimated fetal weight, HC is the head circumference, AC is the abdominal circumference, and FL is the femur length. The new formula proved to be superior to other established equations, showing both the lowest median absolute percentage error (MAE: 6.97) and mean signed percentage error (SPE: 0.40), and the best distribution of absolute percentage errors within prespecified error bounds.

CONCLUSION

This new formula significantly improves weight estimation in fetuses with CDH.