Predictive value of Cardiac Magnetic Resonance: new and old parameters in the natural history of repaired Tetralogy of Fallot

BACKGROUND

Patients with repaired Tetralogy of Fallot (rTOF) often develop pulmonary regurgitation (PR) and right ventricle (RV) dysfunction, experiencing increased mortality and morbidity rates in adulthood. Pulmonary valve replacement (PVR) timing to address PR is controversial. Cardiac Magnetic Resonance (CMR) is the gold standard for morpho-functional evaluation of complex cardiopathies. This study aims to identify CMR parameters predictive of adverse outcomes to help defining the best therapeutic management of rTOF patients.

METHODS

130 rTOF patients who underwent CMR (2006-2019) were enrolled in this retrospective single-center study. CMR, clinical, ECG and exercise data were analyzed. Univariate and multivariate analyses identified clinical and CMR parameters predictive of adverse outcomes both individually (e.g., death, arrhythmias, heart failure (HF), pharmacological therapy, QRS ≥ 160ms) and as composite outcome.

RESULTS

Univariate analysis confirmed RV volumes and RV ejection fraction corrected for PR as adverse outcome predictors and identified interesting correlations: pulmonary artery bifurcation geometry and abnormal interventricular septum (IVS) motion with arrhythmias (p < .001; p = .037), HF (p = .049; p = .005), composite outcome (p = .039; p = .009); right atrium (RA) dimensions with the composite outcome and the outcomes individually (p < .001). The best predictive models by multivariate analysis included sex (male), RV and RA dilation for QRS ≥ 160ms, time form repair to CMR, age at TOF repair and IVS fibrosis for pharmacological therapy.

CONCLUSIONS

Besides RV volumes, new adverse prognostic factors could guide rTOF therapeutic management: pulmonary arteries morphology, abnormal IVS motion, RV dysfunction, RA dilation. Perspective multicentric evaluation is needed to specify their effective role.

TGF-β induces matrisome pathological alterations and EMT in patient-derived prostate cancer tumoroids

Extracellular matrix (ECM) tumorigenic alterations resulting in high matrix deposition and stiffening are hallmarks of adenocarcinomas and are collectively defined as desmoplasia. Here, we thoroughly analysed primary prostate cancer tissues obtained from numerous patients undergoing radical prostatectomy to highlight reproducible structural changes in the ECM leading to the loss of the glandular architecture. Starting from patient cells, we established prostate cancer tumoroids (PCTs) and demonstrated they require TGF-β signalling pathway activity to preserve phenotypical and structural similarities with the tissue of origin. By modulating TGF-β signalling pathway in PCTs, we unveiled its role in ECM accumulation and remodelling in prostate cancer. We also found that TGF-β-induced ECM remodelling is responsible for the initiation of prostate cell epithelial-to-mesenchymal transition (EMT) and the acquisition of a migratory, invasive phenotype. Our findings highlight the cooperative role of TGF-β signalling and ECM desmoplasia in prompting prostate cell EMT and promoting tumour progression and dissemination.

Generation and maturation of human iPSC-derived 3D organotypic cardiac microtissues in long-term culture

Cardiovascular diseases remain the leading cause of death worldwide; hence there is an increasing focus on developing physiologically relevant in vitro cardiovascular tissue models suitable for studying personalized medicine and pre-clinical tests. Despite recent advances, models that reproduce both tissue complexity and maturation are still limited. We have established a scaffold-free protocol to generate multicellular, beating human cardiac microtissues in vitro from hiPSCs-namely human organotypic cardiac microtissues (hOCMTs)-that show some degree of self-organization and can be cultured for long term. This is achieved by the differentiation of hiPSC in 2D monolayer culture towards cardiovascular lineage, followed by further aggregation on low-attachment culture dishes in 3D. The generated hOCMTs contain multiple cell types that physiologically compose the heart and beat without external stimuli for more than 100 days. We have shown that 3D hOCMTs display improved cardiac specification, survival and metabolic maturation as compared to standard monolayer cardiac differentiation. We also confirmed the functionality of hOCMTs by their response to cardioactive drugs in long-term culture. Furthermore, we demonstrated that they could be used to study chemotherapy-induced cardiotoxicity. Due to showing a tendency for self-organization, cellular heterogeneity, and functionality in our 3D microtissues over extended culture time, we could also confirm these constructs as human cardiac organoids (hCOs). This study could help to develop more physiologically-relevant cardiac tissue models, and represent a powerful platform for future translational research in cardiovascular biology.

Prognostic value of pulmonary artery diameter in patients with pulmonary arterial hypertension

Background

Pulmonary artery (PA) dilation is common in pulmonary arterial hypertension (PAH) and may cause left main coronary artery (LMCA) compression. This complication have been sistematically evaluated in patients with angina but no evidence is available for patients asymptomatic for angina.

Purpose

To evaluate the prognostic value of PA diameter and the prevalence of LMCA compression in PAH patients with and without angina.

Methods

All patients with PAH and a baseline angio-CT scan were included. The last angio-CT scan performed was considered for PA diameter increase velocity calculation. Patients with angina or radiological signs of suspected LMCA compression underwent a coronary (cor)-CT scan. Patients with a not negative cor-CT underwent invasive coronary angiography. If clinically indicated invasive coronary angiography was performed without a preliminary cor-CT. To evaluate the predictivity for compression at coronary angiography the PA diameter at cor-CT or at the nearest angio-CT scan was considered.

Results

958 patients were included. PA diameter at baseline is higher in patients with congenital heart disease (CHD) and is not predictive of death. The velocity of PA diameter increase is lower in patients with connective tissue disease and is a risk factor for death in both overall population and different etiological subgroups except CHD and pulmonary veno-occlusive disease. 180 patients had angina and 50 had LMCA compression. 120 patients without angina underwent cor-CT and/or coronary angiography and 15 patients had LMCA compression. The best PA diameter cut-offs predicting LMCA compression in symptomatic/asymptomatic patients were, respectively, 40/42 mm (sensitivity and specificity, respectively, 80 and 72%/87 and 77%).

Conclusion

28% of patients with angina and 13% of patients without angina had LMCA compression. We found a similar PA diameter predicting LMCA compression in patients with or without angina. PA diameter, instead, was not predictive of prognosis (maybe because most deaths were related to heart failure and also because patients with LMCA compression were treated with stenting, possibly preventing sudden cardiac death). Eventually, PA diameter velocity increase is associated with prognosis but this may only reflect a severe disease refractory to medical therapy.

Funding Acknowledgement

Type of funding source: None

Generation of the Becker muscular dystrophy patient derived induced pluripotent stem cell line carrying the DMD splicing mutation c.1705-8 T>C

Becker Muscular dystrophy (BMD) is an X-linked syndrome characterized by progressive muscle weakness. BMD is generally less severe than Duchenne Muscular Dystrophy. BMD is caused by mutations in the dystrophin gene that normally give rise to the production of a truncated but partially functional dystrophin protein. We generated an induced pluripotent cell line from dermal fibroblasts of a BMD patient carrying a splice mutation in the dystrophin gene (c.1705-8 T>C). The iPSC cell-line displayed the characteristic pluripotent-like morphology, expressed pluripotency markers, differentiated into cells of the three germ layers and had a normal karyotype.

P642 Coronary arteriovenous fistulas

Clinical case

A 53 years woman in good health and un uneventful clinical history except for a mild hypercholesteremia was evaluated for palpitations. At the clinical examination she had a systolic murmur 3/6 Levine, with no signs of heart failure.

The ECG showed normal sinus rhythm with a normal heart rate (62bpm), normal atrio-ventricular and intraventricular conduction and normal repolarisation, one supraventricular premature beat. The echocardiography showed normal biventricular dimension and function, no valvular heart diseases, no septal defects, regular aortic dimensions. A giant right coronary was evidenced (Figure, panel a) with an arteriovenous fistula originating from the right coronary artery and draining through the coronary sinus into the right atrium (Figure, panel b). The CT coronary angiogram evidenced an dilated right coronary artery communicating with the coronary sinus (arteriovenous fistula) draining into the right atrium. A smaller arteriovenous fistula was evidenced between the circumflex artery (slightly dilated) and the great cardiac vein. (Figure, panel c-e)

The Treadmill test didn’t evidence an induced ischemia; however the patient didn’t perform a maximal exercise (double product 20400mmHb*bpm). Moreover, during the first steps of recovery frequent supraventricular premature beats were registered with phases of bigeminies followed by a junctional rhythm phase. Thus, a Gated myocardial Perfusion SPECT was performed evidenced a mild stress induced ischemia of the inferolateral and apical left ventricle wall with normal rest perfusion and normal left ventricle volumes (125ml during exercise and 134ml at rest) with a normal ejection fraction ( &gt; 65%). (Figure, panel f)An elective coronarography was planned. The patient is on therapy with beta-blockers and aspirin. The patient is asymptomatic for angina. Antibiotic prophylaxis was recommended for dental, gastrointestinal, or urologic procedures. Discussion: Coronary arteriovenous fistula (CAVF), first described in 1865 by Krausein (1), are a rare congenital heart disease representing less than 0.5% of all congenital heart diseases with an extremely rare prevalence 0.002% in the general population (2). Moreover, therapy of CAVF is still controversial with previous data showing a relatively high rate of myocardial infarction after surgical repair (3). The recent AHA/ACC guideline for the management of adults with Congenital heart disease recommend a review by a knowledgeable team that may include congenital or noncongenital cardiologists and surgeons to determine the role of medical therapy and/or percutaneous or surgical closure (4) Conclusion: CAVF is a very rare congenital heart defect and might be asymptomatic and evidenced by hazard in adults patients. Therapy strategy demands a multidisciplinary team evaluation and should be be individualized according to the clinic presentation, the presence or absence of myocardial ischemia or ventricular dysfunction.

Abstract P642 Figure.