Selection of reference genes is critical for miRNA expression analysis in human cardiac tissue. A focus on atrial fibrillation

MicroRNAs (miRNAs) are emerging as key regulators of complex biological processes in several cardiovascular diseases, including atrial fibrillation (AF). Reverse transcription-quantitative polymerase chain reaction is a powerful technique to quantitatively assess miRNA expression profile, but reliable results depend on proper data normalization by suitable reference genes. Despite the increasing number of studies assessing miRNAs in cardiac disease, no consensus on the best reference genes has been reached. This work aims to assess reference genes stability in human cardiac tissue with a focus on AF investigation. We evaluated the stability of five reference genes (U6, SNORD48, SNORD44, miR-16, and 5S) in atrial tissue samples from eighteen cardiac-surgery patients in sinus rhythm and AF. Stability was quantified by combining BestKeeper, delta-Cq, GeNorm, and NormFinder statistical tools. All methods assessed SNORD48 as the best and U6 as the worst reference gene. Applications of different normalization strategies significantly impacted miRNA expression profiles in the study population. Our results point out the necessity of a consensus on data normalization in AF studies to avoid the emergence of divergent biological conclusions

Heart Team for Left Atrial Appendage Occlusion: A Patient-Tailored Approach

Background and Purpose: Left atrial appendage occlusion (LAAO) is an accepted therapeutic option for stroke prevention; however, the ideal technique and device have not yet been identified. In this study we evaluate the potential role of a heart team approach for patients contraindicated for oral anticoagulants and indicated for left atrial appendage closure, to minimize risk and optimize benefit in a patient-centered decision-making process. Methods: Forty patients were evaluated by the heart team for appendage occlusion. Variables considered were CHA2DS2VASc, HASBLED, documented blood transfusions, comorbidities, event forcing anticoagulant interruption, past medical history, anatomy of the left atrial appendage, and patient quality of life. Twenty patients had their appendage occluded percutaneously (65% male, mean age 72.3 ± 7.5, mean CHA2DS2VASc 4.2 ± 1.5, mean HASBLED 3.5 ± 1.1). The other twenty underwent thoracoscopic occlusion (65% male, mean age of 74.9 ± 8, mean CHA2DS2VASc 6.0 ± 1.5, HASBLED mean 5.4 ± 1.4). Percutaneous patients were on dual antiplatelet therapy for the first three months and aspirin thereafter, whereas the others received no anticoagulant/antiplatelet therapy from the day of surgery. Follow up included TEE, CT scan, and periodical clinical evaluation. Results: Mean duration of procedures and hospital stay were comparable. All patients had complete exclusion of the appendage; at a mean follow up of 33.1 ± 14.1 months, no neurological or hemorrhagic events were reported. Conclusions: A heart team approach may improve the decision-making process for stroke and hemorrhage prevention, where LAAO is a therapeutic option. Percutaneous and thoracoscopic appendage occlusion seem to be comparably safe and effective. An epicardial LAAO could be advisable in patients for whom the risk of bleeding is estimated as being too high for post-procedural antiplatelet therapy

The role of cardiac imaging before and after left atrial appendage standalone thoracoscopic exclusion

Aims: To assess the characteristics of left atrial appendage (LAA) stump and left atrial (LA) volume after standalone totally thoracoscopic LAA exclusion in 40 patients with nonvalvular atrial fibrillation (NVAF) and contraindications to oral anticoagulation (OAC), using cardiac computed tomography (CCT) and transoesophageal echocardiography (TOE). Methods: Using CCT and TOE, we evaluated correct AtriClip Pro II positioning, the presence and characteristics of the LAA stump and the postprocedural LA volume, at 3 months' follow-up. Stump depth was measured with both CCT and TOE using a new method, based on left circumflex artery (LCX) course. Results: After placement of AtriClip, all 40 patients discontinued OAC, and no stroke occurred. LAA exclusion was achieved in 40/40 patients at 3 months' follow-up. LAA stump (depth <10 mm in 12/18 stump, 67%) was observed in 18 patients. The overall (LA + LAA) volume and isolated LA volume were statistically different when comparing cases with and without LAA stump (P < 0.02). LAA ostium dimensions (perimeter and area) and LAA volume correlate with stump depth (P < 0.02). There was a high correlation between CCT and TOE in stump identification and depth measurement (P < 0.02). Compared with the baseline, CCT LA volume increased (P < 0.01) at 3 months' follow-up. Conclusion: Preprocedural and postprocedural CCT and TOE are useful and comparable in patients undergoing standalone totally thoracoscopic exclusion of LAA, because these imaging methods can identify anatomical LAA and LA characteristics predisposing for a postprocedural residual stump