Alternative option for limb reperfusion cannula placement for percutaneous femoral veno-arterial ECMO.

Veno-arterial extracorporeal membrane oxygenation (VA ECMO) is an established last line support for severe, acute cardiorespiratory failure. In the case of VA ECMO, peripheral cannulation via the femoral vessels is often advantageous when compared with the alternative central cannulation, and is associated with better clinical outcomes. One of the specific potential complications of peripheral femoral arterial cannulation for ECMO, however, is ipsilateral distal lower limb ischemia; a consideration especially when cannulating the vessel directly, as distal limb perfusion is invariably compromised by an occlusive effect of the arterial cannula within the femoral artery. The gold standard technique for lower limb reperfusion is a separate size 6-7 Fr cannula inserted proximally into the femoral artery, just below the insertion point of the ECMO return cannula, and connected directly to the ECMO circuit so that the blood flow is also directed distally to perfuse the entire limb. This functions well whether the ECMO cannula has been placed percutaneously or by surgical cut-down. Although proximal femoral arterial placement of the reperfusion cannula is the established and preferred technique, there are many technical challenges which may preclude its placement. Local haematoma or bleeding post ECMO insertion, peripheral vascular disease, constricted vasculature in severely shocked patients, or patient obesity are all common reasons why placement of the proximal reperfusion cannula may be difficult, or impossible. In such instances, our retrograde perfusion technique may maintain limb perfusion and may even be limb saving for patients on VA ECMO support.

The role of renin-angiotensin system activated phagocytes in the SARS-CoV-2 coronavirus infection.

OBJECTIVE: Management of the pandemic caused by the novel coronavirus SARS-CoV-2 challenges both scientists and physicians to rapidly develop, and urgently assess, effective diagnostic tests and therapeutic interventions. The initial presentation of the disease in symptomatic patients is invariably respiratory, with dry cough being the main symptom, but an increasing number of reports reveal multiple-organ involvement. The aim of this review is to summarize the potential role of the renin-angiotensin system activated phagocytes in the pathogenesis of COVID-19 disease. METHODS: Data for this review were identified by searches of PubMed and references from relevant articles using the search terms "SARS," "COVID-19," "renin-angiotensin-system," "phagocyte," "reactive free radical," "antioxidant," "ARDS," "thrombosis," "myocardial," "ischaemia," "reperfusion," "microvascular," and "ACE2." Abstracts and reports from meetings were not included in this work. Only articles published in English between 1976 and 2020 were reviewed. RESULTS: The cellular target of SARS viruses is the angiotensin-converting enzyme 2, a critical regulating protein in the renin-angiotensin system. The elimination of this enzyme by the viral spike protein results in excessive activation of phagocytes, migration into the tissues via the high endothelial venules, and an oxidative burst. In the case of an overstimulated host immune response, not only devastating respiratory symptoms but even systemic or multiorgan involvement may be observed. CONCLUSIONS: Early-stage medical interventions may assist in returning the exaggerated immune response to a normal range; however, some therapeutic delay might result in excessive tissue damages, occasionally mimicking a systemic disease with a detrimental outcome.

Robotic Totally Endoscopic Coronary Artery Bypass Grafting: Systematic Review of Clinical Outcomes from the Past two Decades.

Robotic totally endoscopic coronary artery bypass grafting (TECAB) was introduced in 1998 and has over a period of two decades gradually emerged from single-vessel revascularization to multivessel bypass grafting. Dedicated centers have continuously evolved and further developed this minimally invasive method of coronary bypass surgery. A literature review was conducted to assess intra- and postoperative outcomes of TECAB. PubMed returned 19 comprehensive articles on TECAB. Investigation was focused on perioperative outcome parameters, i.e.: operative time, conversion to larger incision, revision for bleeding, atrial fibrillation, stroke, acute renal failure, and mortality. Outcome from the analysis of 2,397 reported cases showed an average operative time of 291 ± 57 minutes (range 112 to 1,050), conversion rate to larger incisions at 11.5%, and perioperative mortality at 0.8%. Pooled data demonstrated 4.2% operative revision rate due to postoperative hemorrhage, 1.0% stroke incidence, 1.6% acute renal failure, and 13.3% de novo atrial fibrillation. The mean length of hospital stay measured 5.8 ± 1.7 days. Conversion rates and operative times decreased over time. According to data in the literature, coronary bypass surgery carried out in completely endoscopic fashion utilizing robotic assistance can require relatively extensive operative times and conversion rates are somewhat higher than in other robotic cardiac surgery. However, major postoperative events lie in an acceptable range. TECAB remains the surgical revascularization method with the least tissue trauma and represents an opportunity for coronary artery bypass grafting via port access. Rates of major complications are at least similar to conventional surgical access procedures.

A Randomized Controlled Trial of High-Flow Nasal Oxygen (Optiflow) as Part of an Enhanced Recovery Program After Lung Resection Surgery.

BACKGROUND: Patients undergoing thoracic surgery are at risk of postoperative pulmonary complications, which are associated with increased morbidity and mortality. High-flow nasal oxygen therapy delivers humidified, warmed positive airway pressure but has not been tested routinely after thoracic surgery. METHODS: We performed a randomized, controlled, blinded study. Patients undergoing elective lung resection were randomly assigned to either high-flow nasal oxygen or standard oxygen therapy. Patients were otherwise treated within an established enhanced recovery program. The primary outcome was the difference between the preoperative and postoperative 6-minute walk test. Secondary outcomes included hospital length of stay, spirometry, and patient-reported outcomes measured using the Postoperative Quality of Recovery Scale. RESULTS: Fifty-nine patients were randomly assigned to either high-flow nasal oxygen (n = 28) or standard oxygen (n = 31) therapy. We found no difference in the 6-minute walk test outcome or spirometry; however, length of hospital stay was significantly lower in the high-flow nasal oxygen group, median 2.5 days (range, 1 to 22), compared with the standard oxygen group, median 4.0 days (range, 2 to 18); geometric mean ratio was 0.68 (95% confidence interval: 0.48 to 0.86, p = 0.03). No significant differences in recovery domains were found, but patients in the high-flow nasal oxygen group reported significantly higher satisfaction (p = 0.046). CONCLUSIONS: Prophylactic high-flow nasal oxygen therapy, when incorporated into an enhanced recovery program, did not improve 6-minute walk test results but was associated with reduced length of hospital stay and improved satisfaction after lung resection, compared with standard oxygen. This finding has implications for reduced costs and better service provision, and a multicenter trial powered for length of stay is required.

The impact of anaemia and intravenous iron replacement therapy on outcomes in cardiac surgery.

Anaemia is common in patients with cardiac disease and also in those undergoing cardiac surgery. There is increasing evidence that preoperative anaemia is associated with increased patient morbidity and mortality following surgery. We performed a systematic literature review to assess the impact of anaemia and intravenous (IV) iron supplementation on outcomes in cardiac surgery. Sixteen studies examined preoperative anaemia in detail. One study examined the role of preoperative IV iron administration and a further three, the effect of postoperative iron supplementation on haemoglobin (Hb) levels and the need for transfusion. Preoperative anaemia was associated with higher mortality, more postoperative blood transfusions, longer intensive care unit (ICU) and total hospital stay and also a greater incidence of postoperative cardiovascular events. In the single study that examined preoperative IV iron in combination with erythropoietin treatment, there was decreased blood transfusion, shorter hospital stay and an increase in patient survival. However, this was a small retrospective cohort study, with the observation and treatment groups analysed over different time periods. Postoperative administration of IV iron therapy, either alone or in combination with erythropoietin, was not effective in raising Hb levels or reducing red cell concentrate transfusion. On the basis of currently available evidence, the effect of perioperative administration of IV iron to cardiac surgery patients, alone or in combination with erythropoietin, remains unproven. Well-designed and appropriately powered prospective randomized controlled trials are needed to evaluate perioperative iron supplementation in the context of cardiac surgery.

Pre-operative Tei Index does not predict left ventricular function immediately after mitral valve repair.

UNLABELLED: Echocardiographic assessment of systolic left ventricular (LV) function in patients with severe mitral regurgitation (MR) undergoing mitral valve (MV) repair can be challenging because the measurement of ejection fraction (EF) or fractional area change (FAC) in pathological states is of questionable value. The aim of our study was to evaluate the usefulness of the pre-operative Tei Index in predicting left ventricular EF or FAC immediately after MV repair. One hundred and thirty patients undergoing MV repair with sinus rhythm pre- and post-operatively were enrolled in this prospective study. Twenty-six patients were excluded due to absence of sinus rhythm post-operatively. Standard transesophageal examination (IE 33, Philips, Netherlands) was performed before and after cardiopulmonary bypass according to the guidelines of the ASE/SCA. FAC was determined in the transgastric midpapillary short-axis view. LV EF was measured in the midesophageal four- and two-chamber view. For calculation of the Tei Index, the deep transgastric and the midesophageal four-chamber view were used. Statistical analysis was performed with SPSS 17.0. values are expressed as mean with standard deviation. LV FAC and EF decreased significantly after MV repair (FAC: 56±12% vs. 50±14%, P<0.001; EF: 58±11 vs. 50±12Έ P<0.001). The Tei Index decreased from 0.66±0.23 before MV repair to 0.41±0.19 afterwards (P<0.001). No relationship between pre-operative Tei Index and post-operative FAC or post-operative EF were found (FAC: r=-0.061, P=0.554; EF: r=-0.29, P=0.771). CONCLUSION: Pre-operative Tei Index is not a good predictor for post-operative FAC and EF in patients undergoing MV repair.

Implications for repetitive application of acetylcholine in the determination of the mechanisms of endothelium-dependent relaxation.

The influence of repetitive vasodilator concentration response curve determination was investigated in rat mesenteric and femoral small arteries. Arteries were precontracted with noradrenaline and relaxed with acetylcholine (ACh) or K+. Mesenteric arteries exhibited attenuation of ACh-stimulated relaxations during repetitive precontraction/relaxation cycles that was not prevented by SQ29548. Apamin, but not charybdotoxin, prevented the attenuation of this relaxation response. Borderline (p=0.064) statistical differences in the relaxations of mesenteric arteries in response to ACh remained in the presence of the nitric oxide synthase inhibitor L-NNA. In contrast, femoral arterial relaxations increased with repeated acetylcholine challenges. The enhanced responsiveness was prevented with L-NNA or Ba2+. In one experimental series, Ba2+ appeared to be without influence upon K+-stimulated relaxation of femoral arteries but a significant inhibitory effect was revealed when appropriate time control experiments were considered. These experiments reveal that impairment of SK(Ca) function and, to a lesser extent, an impaired NO signalling account for the attenuation of the relaxation responses of rat mesenteric arteries. In contrast, alterations of nitric oxide signalling and inward rectifier K channel activity contribute to enhanced relaxation responses in rat femoral arteries. These experiments highlight the importance of appropriate time control experiments for the proper interpretation of results derived from pharmacological experiments directed toward the elucidation of mechanisms of arterial vasorelaxation.