Skeletonized versus pedicled left internal mammary artery harvesting and risk of sternal wound infection after coronary artery bypass surgery

Background: The left internal mammary artery (LIMA) is the gold standard conduit for coronary artery bypass grafting (CABG). There are two harvesting methods, either pedicled or skeletonized. The choice of any technique must consider its complication profile, especially sternal wound infections (SWI). This study aims to evaluate and compare the occurrence of SWI after pedicled and skeletonized LIMA harvesting techniques for CABG. Methods: This prospective observational study included 300 patients who had CABG between 2016 and 2019. We included patients who had pedicled LIMA (n=200) in group 1 and who had skeletonized LIMA (n=100) in group 2. All patients completed a follow-up period of 3 months after CABG. The evaluation during follow-up included: sternal instability, signs of wound infection, temperature, the microbiological study of wound discharge, and chest computed tomography scan. Results: There was no significant differences in age (p = 0.20), male to female ratio (p = 0.43), body mass index (p = 0.12), NYHA I/II (p = 0.50), diabetes mellitus (p = 0.28), ejection  fraction (p= 0.14), and EuroSCORE II (p= 0.09) between groups. No significant difference in cardiopulmonary bypass time (p = 0.24), and cross-clamp time (p= 0.19) between groups. There was a significant increase in the total operating time in skeletonized LIMA group (212.77±75.25 min vs. 190.78±55 minutes, p= 0.004). Skeletonized LIMA was significantly associated lower incidence of SWI than that with pedicled LIMA (4% vs 15.5%, p= 0.003), and non-significantly lower incidence of deep SWI (1% vs 4.5%, p= 0.11). The risk factors for SWI in patients who had pedicled IMA were obesity (OR: 13.06, 95%CI: 3.98-42.89), diabetes mellitus (OR: 10.51, 95%CI: 2.35-46.84), and excessive diathermy (OR: 12.62, 95%CI: 3.93-40.54). Conclusion: Obesity, diabetes, and the use of excessive diathermy for hemostasis may increase the risk of sternal wound infection with pedicled LIMA harvest compared to skeletonized LIMA in patients undergoing CABG

Antegrade Intermittent Cold Cardioplegia in Comparison to Antegrade Intermittent Warm Cardioplegia in Heart Valve Surgery

Paper withdrawn upon authors request: Request received: 22 May 2020 Paper withdrawn: 22 May 2020 &nbsp

DeVega versus ring annuloplasty in severe functional tricuspid insufficiency and their impact on the right ventricle

Background: Functional tricuspid valve regurgitation secondary to left-sided valve disease is common. DeVega repair is simple, but residual regurgitation with subsequent impairment of the right ventricular function is a concern. This study aims to compare tricuspid valve repair using DeVega vs. ring annuloplasty and their impact on the right ventricle in the early postoperative period and after six months. Methods: This is a prospective cohort study of 51 patients with rheumatic heart disease who underwent tricuspid valve repair for secondary severe tricuspid regurgitation. Patients were divided into two groups: group A; DeVega repair (n=34) and group B; ring annuloplasty repair (n=17). Patients were assessed clinically and by echocardiography before discharge and after six months for the degree of tricuspid regurgitation, right ventricular diameter and tricuspid annular plane systolic excursion (TAPSE). Results: Preoperative echocardiographic assessment showed no difference in left ventricular end-systolic diameter, end-diastolic diameter, ejection fraction and right ventricular diameter, however; group A had significantly better preoperative right ventricular function measured by TAPSE (1.96 ± 0.27 vs1.75 ± 0.31 cm; p=0.02). Group B had significantly longer cardiopulmonary bypass time (127.65 ± 13.56 vs. 111.74 ± 18.74 minutes; p= 0.003) and ischemic time (99.06 ± 11.80 vs. 87.15 ± 16.01 minutes; p= 0.009). Pre-discharge, there was no statistically significant difference in the degree of tricuspid regurgitation, but the right ventricular diameter was significantly lower in group B (2.66 ± 0.41 and 2.40 ± 0.48 cm; p=0.049). After six months of follow up, the degree of tricuspid regurgitation (p= 0.029) and the right ventricular diameter were significantly lower in the ring annuloplasty group (2.56 ± 0.39 and 2.29 ± 0.44 cm; p=0.029). Although there was a statistically significant difference in preoperative TAPSE, this difference disappeared after six months. Conclusion: Both DeVega and ring annuloplasty techniques were effective in the early postoperative period, ring annuloplasty was associated with lesser residual regurgitation and better right ventricular remodeling in severe functional tricuspid regurgitation than DeVega procedure after 6-months of follow up

Video-assisted Minimally Invasive Mitral Valve Surgery versus Conventional Mitral Surgery in Rheumatic Patients

Background: Minimally invasive mitral valve surgery became an attractive option because of its cosmetic advantages over the conventional approach. The superiority of the minimally invasive approach regarding other aspects is still debatable. The aim of our study was to determine the potential benefits of minimally invasive mitral valve replacement with intraoperative video assistance over conventional surgery. Methods: This is a single-center prospective cohort study that included 60 patients with rheumatic heart disease who underwent mitral valve replacement. Patients were divided into two groups: group (A) included patients who had conventional sternotomy (n= 30), and group (B) included patients who had video-assisted minimally invasive mitral valve replacement (n= 30). Intraoperative and postoperative outcomes were compared between both groups. Results: Mortality occurred in one patient in the group (A). Cardiopulmonary bypass time was 118.93 ± 29.84 minutes vs. 64.73 ± 19.16 minutes in group B and A respectively (p< 0.001), and ischemic time was 102.27 ± 30.03 minutes vs. 53.67± 18.46 minutes in group B and A respectively (P < 0.001). Ventilation time was 2.77± 2.27 vs. 6.28 ± 4.48 hours in group B and A respectively (p< 0.001) and blood transfusion was 0.50 ± 0.63 vs. 2.83 ± 1.34 units in group B and A respectively (p< 0.001).  ICU stay was 1.73 ± 0.64 days in the group (B) vs. 4.47 ± 0.94 days in group A (p< 0.001). Postoperative bleeding was 353.33 ± 146.77 ml in the group (B) vs. 841.67 ± 302.03 ml in group A (p <0.001). No conversion to full sternotomy was reported in group B. In group (B), two cases (6.6%) required re-exploration for bleeding vs. four cases (13.2%) in group (A) (p=0.67). The hospital stay was 6.13 ± 1.59 days in the group (B) vs. 13.27 ± 7.62 days in group A (p< 0.001). Four cases (13.3%) developed mediastinitis in group A and in the group (B), there was one case of acute right lower limb embolic ischemia. Conclusion: Video-assisted minimally invasive mitral operations could be a safe alternative to conventional sternotomy with the potential of lesser morbidity and earlier hospital discharge

Serial changes in the serum levels of leptin, homocysteine, galectin-3, total phospholipids and hexosamines among patients undergoing coronary artery bypass grafting

AbstractBackgroundCoronary artery disease (CAD) is the most common cardiovascular disorder in adults. This study was performed to elucidate the role of active leptin, homocysteine, galectin-3, total phospholipids, total, bound, free hexosamines, free-to-bound hexosamines ratio in the pathogenesis of chronic myocardial ischemia and studying the effect of coronary artery bypass grafting (CABG) on their serum levels.MethodsA prospective case control study was carried out on 100 ischemic heart disease male patients undergoing elective CABG and 25 healthy males. Serum levels of total phospholipids, total and free hexosamines, were estimated using spectrophotometric methods, while, serum levels of active leptin, homocysteine and galectin-3 were estimated using ELISA assay kit.ResultsSignificant higher serum active leptin, homocysteine, galectin-3, free hexosamines and free to bound hexosamines ratio levels preoperatively when compared with the control group (p < 0.01 for all) with significant lowering of their serum levels following CABG (p < 0.01 for all) except for active leptin. Significant lower serum total phospholipids, total and bound hexosamines levels preoperatively when compared with the control group (p < 0.01 for all) with significant elevations in their serum levels following CABG (p < 0.01 for all).ConclusionsHigh active leptin, homocysteine, galectin-3, free and free to bound hexosamines ratio and low total phospholipids, total and bound hexosamines play an important role in the pathogenesis of myocardial ischemia. The serum levels of homocysteine, galectin-3, hexosamines and total phospholipids, but not active leptin are significantly lowered following CABG

Peridynamic modelling of propagation of cracks in photovoltaic panels

Photovoltaics (PV) is a method of converting solar energy into direct current electricity using semiconducting materials that exhibit the photovoltaic effect. Cracking in PV panels can cause performance degradation in PV panels. In this study, a new computational methodology, peridynamics is utilised to investigate the cracking behaviour in PV panels. Peridynamics is based on integro-differential equations, and it is a very suitable technique to model crack initiation and propagation. Majority of PV panels are based on silicon solar cell technology. Therefore, polycrystalline material behaviour of silicon is explicitly considered in the model. The numerical framework can be used to support the design of high-performant, long-lasting and fracture-resistant PV panels. The results can also be used to produce practical guidelines aimed to facilitate the decision of PV module rejection due to cracking during production

An innovative cooling technique for floating photovoltaic module: Adoption of partially submerged angle fins

Once the temperature of a photovoltaic panel elevates, two major impacts occur: a significant loss in output power and thermal deterioration, which severely shortens the panel's lifespan. Non-uniform distribution of working temperatures and hence heat spots promote power loss and long-term thermal deterioration. As an electronic power generator, a solar photovoltaic panel requires prompt heat removal from its surfaces to tackle such issues. This is accomplished in the current study by utilizing a novel design heat sink composed of partially submerged angle perforating fins (PSAPF) targeted at increasing heat dissipation from a floating photovoltaic system (FPV). The proposed PSAPF was experimentally investigated for excess heat removal from FPV via both air and water mediums under Mediterranean outdoor environments at Port Said, Egypt. It was demonstrated that in the presence of a surface water current of 0.3 m/s, wind of 5 m/s with direction of 60°, employing PSAPF was considerably more efficient, with 22.77% more productivity and a 33.31% operating temperature reduction when compared to a conventional FPV system. A regression equation has been formed to predict the performance of the designed system through several factors affecting its performance over a wide range of variances

Recent Advances in Floating Photovoltaic Systems

In recent years, floating photovoltaic (FPV) technologies have gained more importance as a key source of clean energy, particularly in the context of providing sustainable energy to buildings. The rise of land scarcity and the need to reduce carbon emissions have made FPV systems a cost-effective solution for generating electricity. This review article aims to explore the rapidly growing trend of floating PV systems, which can be a practical solution for regions with limited land areas. The article discusses the structure of the PV modules used in FPV plants and key factors that affect site suitability choice. Moreover, the article presents various techniques for cooling and cleaning FPV to keep optimal performance and discusses feasible trends and prospects for the technology. Finally, this paper proposes the potential integration of FPV systems with other technologies to enhance energy generation efficiency and discusses other research aimed at the advancement of the technology. By examining the various features of FPV systems, this review article contributes to understanding the advantages and challenges associated with using this sustainable energy technology in different regional contexts.</p