Paradoxical Septal Motion after Uncomplicated Cardiac Surgery: A Consequence of Altered Regional Right Ventricular Contractile Patterns

Paroxysmal interventricular septal motion (PSM) is the movement of the septum toward the right ventricle (RV) during cardiac systole. It occurs frequently after uncomplicated cardiac surgery (CS), including coronary bypass (on-pump and off-pump), valve repair or replacement, and with all types of incisions (sternotomy or mini-thoracotomy). It sometimes resolves quickly but may persist for months or become permanent. Global RV systolic function, stroke volume and ejection fraction remain normal after uncomplicated CS, but regional contractile patterns are altered. There is a decrease in longitudinal shortening but an increase in transverse shortening in the endocardial and epicardial right ventricular muscle fibers, respectively. PSM is a secondary event as there is no loss of septal perfusion or thickening. The increased RV transverse shortening (free wall to septal fibers) may modify septal movement resulting in PSM that compensates for the reduced RV longitudinal shortening, thus preserving normal global right ventricular function.

76 Right mini-thoracotomy surgical Cox-maze (left atrial lesion) vs. catheter ablation using contact force-sensing technology in patients with persistent atrial fibrillation

Aims Pulmonary vein isolation (PVI) often is not sufficient in patients (pts) with persistent atrial fibrillation (AF). Substrate modification (SM) by catheter ablation (CA) of low-voltage zones (LVZ) has yielded favourable results, but those studies were performed before the introduction of contact force (CF) sensing technology. Surgical ablation (SA) studies support the hypothesis that empiric bi-atrial linear ablation (Cox Maze IV procedure) is able to improve success, but there is less data on outcome of patients undergoing left atrial (LA) linear lesions alone. In current guidelines, both CA and SA have Class IIa indication in pts with persistent AF. In this single-centre retrospective study, we analysed the long-term outcomes of CA and SA in pts with persistent AF. Methods and results In the CA group (Figure 1), pts underwent PVI and additional SM in the presence of LVZ (roof line and supero-septal line) using TactiCath™ or SmartTouch™ ablation catheters aiming at contact values ≥10 g < 20 g and FTI >400 g/s. Ablation was performed in a temperature-controlled fashion with energy of 30 W except at the posterior wall (20–25 W). In the SA group (Figure 2), pts underwent ablation procedure (creation of a pure LA endocardial lesion set consistent with the Cox Maze IV) performed by a right mini-thoracotomy approach using the Atricure™ cryoablation probe, a left atrial appendage (LAA) epicardial exclusion using the Atriclip™ system, and mitral valve repair in the presence of severe mitral valve regurgitation. No right atrial lesions were created. 196 pts were included. 120 pts underwent CA [median age: 65 (58–72) years, median LA volume index (LAVI): 66 (56–75) ml/m2], in pts with LVZs PVI + SM was performed [bidirectional block of lines in 100%]. 76 pts underwent SA [median age: 64 (58–74) years, median LAVI 90 (78–103) ml/m2], in 42 pts a mitral valve repair was performed. At 24 months (figure), 89% and 68% of pts were free of AF in the SA and CA group, respectively, mainly without antiarrhythmic drugs (92% SA group and 89% CA group). Conclusions In patients with persistent AF, SA performed by a right mini-thoracotomy approach with linear lesions limited to LA leads to excellent 2-year freedom from AF despite significantly larger LAVI compared with the CA group. LAA epicardial exclusion likely contributed to surgical efficacy by eliminating the LAA as trigger/driver.

Immediate results of minimally invasive redo off-pump coronary artery bypass grafting

Coronary heart disease (CHD) ranks first among the causes of death from cardiac events. Patients who have previously undergone surgical treatment – coronary artery bypass grafting (CABG) – are not immune from the return of angina due to the progression of atherosclerosis in the native coronary arteries or degenerative changes in the shunts. Therefore, the issue of redo surgery in this group of patients is debatable.The aim of the research is to show that the use of alternative sternotomy approaches and the rejection of artificial blood circulation (ABC) are considered as possible measures to improve the results of redo CABGs.Materials and methods. In the Cardiac Surgery Unit No. 1 of the Irkutsk Regional Clinical Hospital from 2003 to 2020, 6773 off-pump CABG surgeries were performed. Of these, 6338 (93.6 %) surgeries were performed using median sternotomy and 435 (6.4 %) surgeries were performed using minitoracotomy or subxyphoid access. Of the 6338 CABG surgeries performed using sternotomy, 58 (0.9 %) were performed repeatedly. All redo surgeries during the period under review were performed by minithoracotomy or subxyphoid access. The indication for redo surgery was the return of angina of III or IV functional class, which did not respond to optimal drug therapy. When performing 54 redo surgeries, the access was leftsided mini-thoracotomy. In 3 patients, CABG was performed by subxyphoid access and in 1 patient – from right-sided mini-thoracotomy.Results. 58 redo CABG surgeries were performed. There was no damage to the access of the heart or functioning shunts. Complications were noted in 5 (8.6 %) patients. In 1 case, a second operation was required due to bleeding from the intercostal artery. In other cases, there were rhythm disturbances, or the need for inotropic support.Conclusion. Performing redo off-pump CABG surgeries using mini-accesses reduces the risk of damage to the heart and functioning shunts, eliminates manipulations on the ascending aorta, and avoids difficulties with cardioplegic protection of the myocardium with a functioning mammarocoronary graft.

The epicardial delivery of cardiosphere derived cells or their extracellular vesicles is safe but of limited value in experimental infarction

The epicardial administration of therapeutics via the pericardial sac offers an attractive route, since it is minimally invasive and carries no risks of coronary embolization. The aim of this study was to assess viability, safety and effectiveness of cardiosphere-derived cells (CDCs), their extracellular vesicles (EVs) or placebo administered via a mini-thoracotomy 72 h after experimental infarction in swine. The epicardial administration was completed successfully in all cases in a surgery time (knife-to-skin) below 30 min. No significant differences between groups were found in cardiac function parameters evaluated using magnetic resonance imaging before therapy and at the end of the study, despite a trend towards improved function in CDC-treated animals. Moreover, infarct size at 10 weeks was smaller in treated animals, albeit not significantly. Arrhythmia inducibility did not differ between groups. Pathological examination showed no differences, nor were there any pericardial adhesions evidenced in any case 10 weeks after surgery. These results show that the epicardial delivery of CDCs or their EVs is safe and technically easy 3 days after experimental myocardial infarction in swine, but it does not appear to have any beneficial effect on cardiac function. Our results do not support clinical translation of these therapies as implemented in this work.

Mini Sternotomy and Mini Thoracotomy for Aortic Valve Replacement: Is There a Difference?

Background: Minimally invasive valve replacement is increasingly accepted among surgeons and patients alike. Ministernotomy and minithoracotomy are the most used incisions in the minimally aortic valve replacement. The superiority of one incision over the other still is debatable with a few centers having the opportunity to compare them head-to-head. Methods: A retrospective analysis of 260 patients, who underwent mini AVR, with 132 patients in the ministernotomy group and 128 patients in the minithoracotomy group. Operative details, mortality, wound cosmetics, and postoperative pain were among the primary end points. Results: A predominance of female gender has been observed in both groups. The cross-clamp and total bypass times were significantly lower in MS compared with the MT approach (63.61±16.115 vs. 70.75±33.274 min, P = 0.028, and 91.90±26.365 vs. 112.24±51.634 min, P < 0.001, respectively). The minithoracotomy group had significantly shorter lengths of wounds (5.1 ± 0.6 vs. 8.48±0.344 cm, P < 0.001). The ministernotomy group had significantly lower postoperative pain scores either in the ICU, at hospital discharge, or after 30 days at the outpatient clinic, where scores compared with MT (4.46±1.23 vs. 5.23±1.12, P < 0.001, 1.6±0.84 vs. 1.83±0.72, P = 0.019, and 1.28±0.67 vs. 1.47±0.53, P = 0.012, respectively). Conclusion: Both minimally invasive incisions for AVR proved their safety and efficacy. While the ministernotomy has the advantage of less postoperative pain and pleural complications, the minithoracotomy incision has its unmatched aesthetic appeal.

Endo-Aortic vs. Trans-Thoracic Clamping in Right Mini-Thoracotomy Mitral Valve Surgery: Outcome on Myocardial Protection

Background: Perfusion strategies and aortic clamping techniques for right mini-thoracotomy mitral valve (MV) surgery have evolved over time and remarkable short- and long-term results have been reported. However, some concerns have raised about the adequacy of myocardial protection during the minimally invasive approach, particularly with the endo-aortic clamp (EAC). Aim of this study was to compare the efficacy, in terms of myocardial preservation, of the EAC with the trans-thoracic aortic clamp (TTC) in patients undergoing right mini-thoracotomy MV surgery.Methods: A single center, prospective observational study was performed on patients undergoing right mini-thoracotomy MV surgery with retrograde arterial perfusion and EAC or TTC. A propensity matched analysis was performed to compare the two groups. Primary outcome was the comparison between cardiac troponin T levels measured at different time-points after surgery.Results: Eighty EAC patients were compared with 37 TTC patients. No cases of myocardial infarction or low cardiac-output syndrome were overall reported. No differences were recorded in terms of stroke, peri-operative mortality, and in the release of myocardial markers, lactates levels and need for inotropic support at different time-points after surgery. CK-MB peak levels were significantly lower in the EAC group.Conclusion: Despite concerns arising about the EAC, this prospective study shows equivalence in terms of myocardial preservation of the EAC compared with the TTC in patients undergoing right mini-thoracotomy MV surgery.