Effect of the degree of ischaemic injury and reoxygenation time on the type of myocardial cell death in man: role of caspases

BACKGROUND: The importance of apoptosis in the injury sustained by the human myocardium during ischaemia and reoxygenation and the underlying mechanisms remain unclear. To quantify apoptosis and necrosis induced by simulated ischaemia/reoxygenation in the human atrial myocardium, free-hand sections of right atrial appendage (n = 8/group) were subjected to 90 minutes simulated ischaemia followed by 2, 8 and 24 hours reoxygenation. RESULTS: Apoptosis, as assessed by TUNEL, was greater than necrosis after 90 minutes simulated ischaemia and 2 hours reoxygenation (35.32 ± 3.22% vs 13.55 ± 1.3%; p < 0.05) but necrosis was greater than apoptosis by 24 hours reoxygenation (45.20 ± 2.75% vs 4.82 ± 0.79%; p < 0.05). Total caspase activation was similar after 90 minutes simulated ischaemia followed by 2 hours and 24 hours reoxygenation (515270 ± 99570 U vs 542940 ± 95216 U; p = NS). However, caspase-3 like activation was higher at 2 hours than at 24 hours reoxygenation (135900 ± 42200 U vs 54970 ± 19100 U; p < 0.05). Inhibition of caspase-3 by z.DEVD.fmk (70 nM) almost completely abolished apoptosis from 23.26 ± 2.854% to 0.73 ± 0.28 % (p < 0.05), without affecting necrosis. CONCLUSION: Cell death by apoptosis and necrosis in the human myocardium subjected to simulated ischaemia/reoxygenation depends on the degree of the ischaemic insult and have a different time-course with apoptosis happening early during reoxygenation and necrosis becoming more important later. Importantly, the apoptosis induced by simulated ischaemia/reoxygenation is mainly mediated by activation of caspase-3 but it does not affect necrosis

Current Perspectives on Contemporary Rheumatic Mitral Valve Repair

The surgical management of rheumatic mitral valve disease remains a challenge for cardiac surgeons. Durability of mitral valve repair (MVr) is likely compromised not simply due to high technical demand, but surgeon reluctance, despite boasting copious advantages over MV replacement. This comprehensive review aims to evoke a deeper understanding of MVr concepts necessary to abate these limitations and shift mindset towards a more holistic approach to repair. Details of commonly utilized techniques in contemporary MVr for rheumatic heart disease will be discussed. Of importance, the reparative procedures will be mapped to an in-depth physiological exploration of the mitral complex-dynamism and rheumatic interplay. This is further emphasized by outlining the current “aggressive” resection strategy in contemporary rheumatic MVr

The Inflammatory Response to Miniaturised Extracorporeal Circulation: A Review of the Literature

Conventional cardiopulmonary bypass can trigger a systemic inflammatory response syndrome similar to sepsis. Aetiological factors include surgical trauma, reperfusion injury, and, most importantly, contact of the blood with the synthetic surfaces of the heart-lung machine. Recently, a new cardiopulmonary bypass system, mini-extracorporeal circulation (MECC), has been developed and has shown promising early results in terms of reducing this inflammatory response. It has no venous reservoir, a reduced priming volume, and less blood-synthetic interface. This review focuses on the inflammatory and clinical outcomes of using MECC and compares these to conventional cardio-pulmonary bypass (CCPB). MECC has been shown to reduce postoperative cytokines levels and other markers of inflammation. In addition, MECC reduces organ damage, postoperative complications and the need for blood transfusion. MECC is a safe and viable perfusion option and in certain circumstances it is superior to CCPB

Surgical repair of Stanford type A aortic dissection in elderly patients:a contemporary systematic review and meta-analysis

BACKGROUND: The results of surgical treatment of type A aortic dissection (AAD) in the elderly are controversial and aggravated by a higher operative mortality rate. The studies published in this subset of patients are mainly retrospective analyses or small samples from international registries. We sought to investigate this topic by conducting a contemporary meta-analysis of the most recent observational studies. METHODS: A systematic literature search was conducted for any study published in the last five years on aortic dissection treated surgically in patients 70 years and older. A pooled risk-ratio meta-analysis has been conducted three main post-operative outcomes: short-term mortality, stroke and acute kidney injury. RESULTS: A total of 11 retrospective observational studies have been included in the quantitative meta-analysis. Pooled meta-analysis showed an increased risk of short term mortality for the elderly population [relative risk (RR) =2.25; 95% CI, 1.79–2.83; I(2)=0%; P<0.0001], and this has been confirmed in a sub-analysis of patients 80 years and older. The risk of having stroke (RR =1.15; 95% CI, 0.89–1.5; I(2)=0%; P=0.28) and acute kidney injury (RR =0.79; 95% CI, 0.5–1.25, I(2)=14%, P=0.31) after surgery were comparable to the younger cohort of patients. CONCLUSIONS: Although affected by an increased risk of short-term mortality in the elderly, surgical repair remains the treatment of choice for AAD. The main post-operative outcomes are comparable to younger patients and the mid-term survival rates are acceptable

Minimally invasive versus transcatheter closure of secundum atrial septal defects:a systematic review and meta-analysis

BACKGROUND: Limited data exists demonstrating the efficacy of minimally invasive surgery (MIS) compared to transcatheter (TC) closure of atrial septal defects (ASD). This systematic review and meta-analysis aims to compare post-operative outcomes of MIS versus TC repair in ASD closure. METHODS: PubMed, Medline and EMBASE were searched from inception until June 2018 for randomised and observational studies comparing post-operative outcomes for MIS and TC repair. The studies were reviewed for bias using the ROBINS-I Score and pooled in a meta-analysis using STATA (version 15). RESULTS: Six observational studies, involving 1524 patients assessing three primary and five secondary outcomes were included. Evidence suggests TC repair yielded shorter hospital stay (MD = 3.32, 95% CI 1.04–5.60) and lower rates of transient atrial fibrillation (AF) (RR = 0.48, 95% CI 0.20–1.15). TC repair patients also had fewer pericardial effusions (RR = 0.27, 95% CI 0.05–1.54, I(2) = 0.0%) and pneumothoraxes (RR = 0.18, 95% CI 0.04–0.80, I(2) = 0.0%). However, TC repair results in more minor residual shunts (RR = 6.04, 95% CI 1.69–21.63 in favour of MIS, I(2) = 39.0%). No differences were found for incidences of strokes (RR = 1.58, 95% CI 0.23–10.91, I(2) = 19.3%), unexpected bleeding (RR = 0.44, 95% CI 0.19–1.04, I(2) = 0.0%) and blood transfusion (RR = 0.39, 95% CI 0.09–1.59, I(2) = 0.0%). CONCLUSIONS: MIS closure for ASD has similar outcomes compared to TC repair. However, the lack of randomised literature related to MIS versus TC repair for ASD closure warrants further evidence in the form of RCTs to further support these findings