Feasibility and image quality of myocardial perfusion imaging by CMR in patients with conditional and non-conditional cardiac devices

Purpose

First, to determine image quality using different cardiovascular magnetic resonance (CMR) perfusion protocols in patients with all available active device types in a real-world setting, including non-conditional devices.

Second, to demonstrate feasibility of high-quality perfusion imaging using spoiled gradient echo (sGE) protocols for non-invasive stress-testing.

Methods

From August 2020 to March 2022, N=222 patients with active cardiac implantable electronic devices (CIED) were scanned on a 1.5-T MR scanner (Philips Ingenia and Ambition). Our CMR scanning protocol was tailored to the clinical indication, and whenever myocardial perfusion imaging was possible, both a conventional steady-state-free-precession (SSFP)-based and a modified sGE-perfusion protocol were applied. Such a tailored perfusion protocol was performed in N=119 patients (70% men) with exclusively left-sided devices (pacemaker (PM), n=45; implantable cardioverter-defibrillator (ICD), n=46; subcutaneous ICD (S-ICD), n=15 and cardiac resynchronization therapy-pacemaker (CRT-P, n=5) or -defibrillator (CRT-D, n=8) with a percentage of 10% non-conditional devices. For assessment of image quality, a semi-quantitative 4-point grading scale was used based on a standard 16-segment model.

Results

A total of N=33 stress-tests with either regadenosone, adenosine or dobutamine and N=86 rest perfusion protocols were performed. Asynchronous pacing was required in 34% of the patients due to a heart rate of <40bpm. Device interrogation before and after CMR scanning showed no significant changes. Image quality was substantially better in sGE-based perfusion protocols compared to conventional SSFP-based perfusion in ICD, CRT-D and S-ICD patients (p<0.001). In patients with PM/ CRT-P image quality was neither significantly impaired in SSFP- nor in sGE-based protocols. Most device artefacts were located primarily in the anterior myocardial segments (1, 7, 13) in transvenous implanted devices and lateral in SICD-patients. A significant relationship between the extent of device artefacts and the parameters LVEDV (p=0.03), LVESV (p=0.005) and non-conditional devices (p=0.029) in SSFP-perfusion protocols were found in patients with PM/CRT-P. In contrast, there was no correlation between clinical and CMR-parameters in patients with ICD/ CRT-D. In S-ICD-patients, there was an inverse relationship between the extent of device artefact and age (p=0.006), BMI (p=0.001) in sGE-perfusion.

Conclusion

Myocardial perfusion imaging by CMR is safe and feasible with high image-quality in patients with all kinds of CIEDs – including MR-conditional as well as non-conditional devices. When performing CMR-based myocardial perfusion imaging in patients with left-sided ICD/CRT-D/S-ICD, a sGE-based perfusion-protocol should be preferred compared to conventional SSFP-based perfusion protocols in order to achieve artefact-free and well interpretable images.

Funding Acknowledgement

Type of funding sources: None.

Therapeutic value of tafamidis in patients with wild-type transthyretin amyloidosis (ATTRwt) with cardiomyopathy based on cardiovascular magnetic resonance (CMR) imaging

Background

Tafamidis was approved in Europe for the treatment of cardiomyopathy (CM) in patients with transthyretin amyloidosis (ATTR) in April 2020. So far, real-world data addressing the therapeutic value of tafamidis for the treatment of ATTR-CM are scarce. The purpose of this study was to carefully analyse the therapeutic benefit of tafamidis in patients with wild-type ATTR (ATTRwt) and CM (ATTRwt-CM) after one year of therapy based on serial multi-parametric cardiovascular magnetic resonance (CMR) imaging.

Purpose

The purpose of this study was to carefully analyse the therapeutic benefit of tafamidis in patients with wild-type transthyretin amyloidosis (ATTRwt) and cardiomyopathy (ATTRwt-CM) after one year of therapy based on serial multi-parametric cardiovascular magnetic resonance (CMR) imaging.

Methods

The present study comprised N=40 patients with ATTRwt-CM who underwent two serial multi-parametric CMR studies within a follow-up period of 12±3 months. Baseline (BL) clinical parameters, serum biomarkers and CMR findings were compared to follow-up (FU) values in patients with treated “with” tafamidis 61mg daily (n=20, group A) and those “without” tafamidis therapy (n=16, group B). CMR studies were performed on a 1.5-T system and comprised (amongst others) cine-imaging for assessment of cardiac anatomy and function including 3D longitudinal strain assessment. In addition, a modified Look-Locker inversion recovery (MOLLI) T1-mapping sequence was performed for measurement of pre- and post-contrast myocardial T1-values with additional calculation of extracellular volume fraction (ECV)-values.

Results

While left ventricular ejection fraction (LV-EF), left ventricular mass index (LVMi), left ventricular wall thickness (LVWT), native T1- and ECV-values remained unchanged in the tafamidis group A, a slight reduction in LV-EF (p=0.003) as well as a subtle increase in LVMi (p=0.034), in LVWT (p=0.001), in native T1- (p=0.038) and ECV-values (p=0.017) were observed in the untreated group B. Serum NT-proBNP levels showed an overall increase in both groups, however, with the untreated group B showing a relatively higher increase compared to the treated group A. Assessment of NYHA class did not result in significant intra-group differences when BL were compared with FU, but a trend to improvement in the treated group A compared to a worsening trend in the untreated group B (Δp=0.005).

Conclusion

Tafamidis does not improve cardiac phenotype in patients with ATTRwt-CM after one year of therapy. However, tafamidis seems to slow down cardiac disease progression in patients with ATTRwt-CM compared to those without tafamidis therapy based on multi-parametric CMR data already after one year of therapy.

Funding Acknowledgement

Type of funding sources: None.

The effect of prolonged Intraaortic ballon pump (IABP) support on right ventricular function in end-stage heart failure

Introduction

Right Ventricular (RV) function has prognostic implications in end-stage heart failure (ESHF) patients. RV failure following Left Ventricular Assist Device (LVAD) implantation increases morbidity and mortality. Achieving optimal RV function before LVAD implantation is of paramount importance.

Purpose

Purpose was to investigate the effect of Intra-aortic Balloon Pump (IABP) on RV function optimization in patients with bi-ventricular ESHF.

Methods

ESHF patients with poor RV function, presenting with acutely decompensated heart failure resistant to inotropes/vasopressors, thus requiring IABP for stabilization, were prospectively enrolled. Serum biochemistry, echocardiography and invasive hemodynamics were applied and eligibility for LVAD according to RV function was determined on the basis of pre-specified criteria (Right atrium Pressure (RAP) <12mmHg, Pulmonary Artery Pulsatility index (PAPi) >1.85, RAP/Pulmonary Capillary Wedge Pressure (PCWP) <0.67, RV strain <−14%). LV and RV tissue was harvested during LVAD or bi-ventricular mechanical circulatory implantation or at the time of heart transplantation. Fibrosis of the myocardial tissue was quantified.

Results

Sixteen patients aged 38±14 years were enrolled. Duration of IABP support was 62±50 (3–180) days. Three patients deteriorated requiring additional mechanical circulatory support. Two patients were stabilized without RV function improvement. In the remaining 11 patients, RV improved and fulfilled LVAD eligibility criteria (IABP responders); RA and RA/PCWP decreased from 18±6 to 10±4mmHg (p=0.0001) and from 0.60±0.19 to 0.42±0.11 (p=0.011) respectively. PAPi and RV strain improved from 1.46±0.65 to 3.20±0.58 (p=0.0001) and from −12.9±3.4% to −18.7±1.7% (p=0.0001) respectively. Significantly lower baseline NTproBNP and total bilirubin values were observed in the responders group. Six patients finally received LVAD and none suffered RV failure post-operatively (the remaining 5 were successfully transplanted). RV fibrosis correlated with post-IABP NTproBNP (r=0.91, p=0.001), total bilirubin (r=0.79, p=0.011), RAP (r=0.78, p=0.014), PAPi (r=−0.69, p=0.040), RAP/PCWP (r=0.74, p=0.022) and LV fibrosis (r=0.77, p=0.016), but not with baseline (pre-IABP) parameters.

Conclusions

Prolonged IABP support contributes to partial RV function recovery in patients with ESHF and bi-ventricular failure, thus leading to eligibility for LVAD implantation. RV fibrosis may predict RV response to IABP and post-IABP eligibility for LVAD.

Funding Acknowledgement

Type of funding sources: None.

1438MicroRNA editing is integral for interleukin-6 trans-signalling and leukocyte trafficking to ischemic tissues

Background/Aim

Adenosine to inosine RNA editing is an essential post-transcriptional RNA modification catalysed by adenosine deaminase acting on RNA-1 and -2 (ADAR1; ADAR2). Endothelial cells (ECs) attract and guide leukocytes to sites of ischemic tissue injury. Here we studied the role of RNA editing in ischemic disease.

Methods

Primary human and murine vascular endothelial cell cultures were used to assess the EC responses to interleukin-6 (IL-6) or ischemia. For the animal studies, the effect of ADAR2 in acute and chronic ischemic disease was evaluated in cremaster muscle microcirculation by intravital microscopy, in peritoneal cavity after sterile peritonitis and in gastrocnemius muscle after hind-limb ischemia by 8-colour flow cytometry and immunohistochemistry (IHC) studies of Adar2−/−/tg as well as of i(nducible)EC-ADAR2 knockout (KO) mice. For the mechanistic studies, deep RNA sequencing, qRT-PCR, western blot, confocal microscopy, target-specific microRNA (miRNA) editing studies, RNA-immunoprecipitation, miRNA/plasmid silencing/overexpression and luciferase reporter assays were used among others. For human studies, ischemic tissues derived from patients with acute or chronic ischemic heart disease were processed.

Results

ADAR2, but not ADAR1, expression is induced by >2-fold in hypoxic ECs and in ischemic vascular ECs in mice and humans. Unbiased gene ontology analysis of the EC transcriptome indicated that ADAR2 controls inflammatory responses and predominantly the expression of interleukin-6-signal transducer (IL6ST), the co-receptor of IL-6. Subsequently, ADAR2 controls IL-6 trans-signalling in ECs as documented by the STAT3 phosphorylation and expression of the downstream leukocyte adhesion molecules, E-selectin and VCAM-1. IL-6-inflamed cremaster muscles showed that rolling and adhesion of leukocyte subsets to vascular wall were severely impaired in Adar2−/−/tg mice. Leukocyte transmigration was also diminished by >2-fold in Adar2−/−/tg and in iEC-ADAR2 KO mice in response to IL-6 or ischemia. Similar results were obtained for leukocyte rolling, adhesion and infiltration after acute (4h) and chronic (3d; 21d) ischemia from iEC-ADAR2 KO mice and human ischemic muscle tissues. Next we studied how ADAR2 controls IL6ST expression. ADAR2-deficient vascular EC miRNAome revealed the upregulation of a conserved group of miRNAs targeting the IL6ST mRNA including miR-199a-5p and miR-335-3p. At a single-nucleotide level, ADAR2-induced RNA editing of the stem loops of the primary miR-199a1/2 and miR-335 directly disrupted Drosha recruitment to both and thus inhibited their maturation process. Accordingly, rescue experiments using miRNA-inhibitors restored IL6ST levels after ADAR2 deficiency.

Conclusion

Taking together, inhibition of the microRNA maturation process by ADAR2-mediated RNA editing is integral for IL-6 trans-signalling in vascular endothelium and subsequent leukocyte trafficking to ischemic tissues in mice and humans.