Conventional versus minimally invasive extra-corporeal circulation in patients undergoing cardiac surgery: A randomized controlled trial (COMICS).

INTRODUCTION: The trial hypothesized that minimally invasive extra-corporeal circulation (MiECC) reduces the risk of serious adverse events (SAEs) after cardiac surgery operations requiring extra-corporeal circulation without circulatory arrest. METHODS: This is a multicentre, international randomized controlled trial across fourteen cardiac surgery centres including patients aged ≥18 and <85 years undergoing elective or urgent isolated coronary artery bypass grafting (CABG), isolated aortic valve replacement (AVR) surgery, or CABG + AVR surgery. Participants were randomized to MiECC or conventional extra-corporeal circulation (CECC), stratified by centre and operation. The primary outcome was a composite of 12 post-operative SAEs up to 30 days after surgery, the risk of which MiECC was hypothesized to reduce. Secondary outcomes comprised: other SAEs; all-cause mortality; transfusion of blood products; time to discharge from intensive care and hospital; health-related quality-of-life. Analyses were performed on a modified intention-to-treat basis. RESULTS: The trial terminated early due to the COVID-19 pandemic; 1071 participants (896 isolated CABG, 97 isolated AVR, 69 CABG + AVR) with median age 66 years and median EuroSCORE II 1.24 were randomized (535 to MiECC, 536 to CECC). Twenty-six participants withdrew after randomization, 22 before and four after intervention. Fifty of 517 (9.7%) randomized to MiECC and 69/522 (13.2%) randomized to CECC group experienced the primary outcome (risk ratio = 0.732, 95% confidence interval (95% CI) = 0.556 to 0.962, p = 0.025). The risk of any SAE not contributing to the primary outcome was similarly reduced (risk ratio = 0.791, 95% CI 0.530 to 1.179, p = 0.250). CONCLUSIONS: MiECC reduces the relative risk of primary outcome events by about 25%. The risk of other SAEs was similarly reduced. Because the trial terminated early without achieving the target sample size, these potential benefits of MiECC are uncertain.

The impact of COVID-19 prevention measures on surgical wound infection rates post-cardiac surgery.

The COVID-19 pandemic had a huge impact on medical services. Several measures have been implemented to reduce the risk of viral transmission. In this paper, we assessed the impact of these measures on surgical wound infection rates in patients post-cardiac surgery. Hypothesis testing was used to compare post-cardiac operation infection rates between the year prior to the COVID-19 pandemic being declared and the first 13 months of the pandemic. The infection rates in 969 patients with operations between 01/03/2019 and 29/02/2020 were compared to those of 925 patients with cardiac surgery between 01/03/2020 and 31/03/2021. Infection rates for various operative urgencies and infection types were analysed. To compare infection rates, a two-tailed pooled z-test using the difference in infection proportions was performed. A 5% significance level was used and only categories with at least 10 patients in both the pre-covid and covid populations were tested. For leg infections, only operations involving coronary artery bypass grafting were included. To ensure that any differences in outcomes were not due to differences in patient demographics resulting in unequal operative risks, Euroscore II values, a measure of cardiac operative risk, were compared between the pre-covid and post-covid cohorts. The Mann-Whitney U-test was used to determine whether the distributions of Euroscore II values were likely to be drawn from the same population. A significance level of 5% was used. A total of 1901 patients (932 during the COVID-19 pandemic) were included in this study. Significant reduction in post-operative infections for all patients undergoing cardiac surgery from 4.3% of patients before COVID to 1.5% during the pandemic. During the pandemic, fewer elective and more urgent operations were performed. This study suggests a significant role of iatrogenic causes in wound infections prior to the pandemic. The implementation of COVID-19 prevention measures in healthcare providers can reduce surgical infection rates. As COVID-19-related restrictions have been eased, we suggest maintaining them in healthcare providers to reduce the incidence of surgical wound infections.

Effect of Transcatheter Aortic Valve Implantation vs Surgical Aortic Valve Replacement on All-Cause Mortality in Patients With Aortic Stenosis: A Randomized Clinical Trial.

Importance: Transcatheter aortic valve implantation (TAVI) is a less invasive alternative to surgical aortic valve replacement and is the treatment of choice for patients at high operative risk. The role of TAVI in patients at lower risk is unclear. Objective: To determine whether TAVI is noninferior to surgery in patients at moderately increased operative risk. Design, Setting, and Participants: In this randomized clinical trial conducted at 34 UK centers, 913 patients aged 70 years or older with severe, symptomatic aortic stenosis and moderately increased operative risk due to age or comorbidity were enrolled between April 2014 and April 2018 and followed up through April 2019. Interventions: TAVI using any valve with a CE mark (indicating conformity of the valve with all legal and safety requirements for sale throughout the European Economic Area) and any access route (n = 458) or surgical aortic valve replacement (surgery; n = 455). Main Outcomes and Measures: The primary outcome was all-cause mortality at 1 year. The primary hypothesis was that TAVI was noninferior to surgery, with a noninferiority margin of 5% for the upper limit of the 1-sided 97.5% CI for the absolute between-group difference in mortality. There were 36 secondary outcomes (30 reported herein), including duration of hospital stay, major bleeding events, vascular complications, conduction disturbance requiring pacemaker implantation, and aortic regurgitation. Results: Among 913 patients randomized (median age, 81 years [IQR, 78 to 84 years]; 424 [46%] were female; median Society of Thoracic Surgeons mortality risk score, 2.6% [IQR, 2.0% to 3.4%]), 912 (99.9%) completed follow-up and were included in the noninferiority analysis. At 1 year, there were 21 deaths (4.6%) in the TAVI group and 30 deaths (6.6%) in the surgery group, with an adjusted absolute risk difference of -2.0% (1-sided 97.5% CI, -∞ to 1.2%; P < .001 for noninferiority). Of 30 prespecified secondary outcomes reported herein, 24 showed no significant difference at 1 year. TAVI was associated with significantly shorter postprocedural hospitalization (median of 3 days [IQR, 2 to 5 days] vs 8 days [IQR, 6 to 13 days] in the surgery group). At 1 year, there were significantly fewer major bleeding events after TAVI compared with surgery (7.2% vs 20.2%, respectively; adjusted hazard ratio [HR], 0.33 [95% CI, 0.24 to 0.45]) but significantly more vascular complications (10.3% vs 2.4%; adjusted HR, 4.42 [95% CI, 2.54 to 7.71]), conduction disturbances requiring pacemaker implantation (14.2% vs 7.3%; adjusted HR, 2.05 [95% CI, 1.43 to 2.94]), and mild (38.3% vs 11.7%) or moderate (2.3% vs 0.6%) aortic regurgitation (adjusted odds ratio for mild, moderate, or severe [no instance of severe reported] aortic regurgitation combined vs none, 4.89 [95% CI, 3.08 to 7.75]). Conclusions and Relevance: Among patients aged 70 years or older with severe, symptomatic aortic stenosis and moderately increased operative risk, TAVI was noninferior to surgery with respect to all-cause mortality at 1 year. Trial Registration: isrctn.com Identifier: ISRCTN57819173.

A review of the best method of leg wound closure following open harvesting of the long saphenous vein for coronary artery bypass grafting.

Uncertainty exists around the optimal method of leg wound closure following open long saphenous vein harvesting in adults undergoing coronary artery bypass graft surgery (CABG). Such is evident from the variety observed in the closure approach utilised. Consequently, a best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was 'following open long saphenous vein harvesting in adults undergoing CABG, is single-layer leg wound closure superior to multiple-layer closure in terms of post-operative complications encountered? '. Altogether 382 papers on Ovid Embase and Ovid Medline, 301 papers on PubMed and 11 papers on the Cochrane database were found using the reported search. From the screened articles, 6 represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. We conclude that the best method of leg closure following open saphenous vein harvesting for CABG is single-layer cutaneous closure. The use of a suction drain to eliminate the dead space should be considered on a case-to-case basis by the lead operating surgeon with the patient's characteristics and their own expertise in mind.

Antimicrobial prophylaxis in adult cardiac surgery in the United Kingdom and Republic of Ireland.

BACKGROUND: Deep sternal wound infections are a financially costly complication of cardiac surgery with serious implications for patient morbidity and mortality. Prophylactic antimicrobials have been shown to reduce the incidence of infection significantly. In 2018, the European Association for CardioThoracic Surgery (EACTS) provided clear guidance advising that third-generation cephalosporins are the first-line prophylactic antimicrobial of choice for cardiac surgery via median sternotomy as a result of their broad spectrum of activity and association with reduced postoperative mortality. Despite this guidance, it was believed that UK practice differed from this as a consequence of national concerns surrounding cephalosporins use and Clostridioides difficile infection. METHODS: A survey was developed and distributed to all UK and Republic of Ireland (ROI) cardiac surgery centres in January 2019 to quantify this variation. RESULTS: Of the 38 centres, 34 responded. Variation existed between the antimicrobial agent used, as well as the dosage, frequency and duration of suggested regimens even among centres using the same antimicrobial agent. The most common antimicrobial prophylaxis prescribed was a combination of flucloxacillin and gentamicin (16, 47%). Followed by cefuroxime (6, 17.6%) and cefuroxime combined with a glycopeptide (4, 11.7%). In patients colonised with methicillin-resistant Staphylococcus aureus or those with penicillin allergy gentamicin combined with teicoplanin was most common (42% and 50%, respectively). DISCUSSION: This variation in antimicrobial agents and regimens may well contribute to the varying incidence of surgical site infection seen across the UK and ROI.

Minimally invasive versus conventional sternotomy for Mitral valve repair: protocol for a multicentre randomised controlled trial (UK Mini Mitral).

INTRODUCTION: Numbers of patients undergoing mitral valve repair (MVr) surgery for severe mitral regurgitation have grown and will continue to rise. MVr is routinely performed via median sternotomy; however, there is a move towards less invasive surgical approaches.There is debate within the clinical and National Health Service (NHS) commissioning community about widespread adoption of minimally invasive MVr surgery in the absence of robust research evidence; implementation requires investment in staff and infrastructure.The UK Mini Mitral trial will provide definitive evidence comparing patient, NHS and clinical outcomes in adult patients undergoing MVr surgery. It will establish the best surgical approach for MVr, setting a standard against which emerging percutaneous techniques can be measured. Findings will inform optimisation of cost-effective practice. METHODS AND ANALYSIS: UK Mini Mitral is a multicentre, expertise based randomised controlled trial of minimally invasive thoracoscopically guided right minithoracotomy versus conventional sternotomy for MVr. The trial is taking place in NHS cardiothoracic centres in the UK with established minimally invasive mitral valve surgery programmes. In each centre, consenting and eligible patients are randomised to receive surgery performed by consultant surgeons who meet protocol-defined surgical expertise criteria. Patients are followed for 1 year, and consent to longer term follow-up.Primary outcome is physical functioning 12 weeks following surgery, measured by change in Short Form Health Survey (SF-36v2) physical functioning scale. Early and 1 year echo data will be reported by a core laboratory. Estimates of key clinical and health economic outcomes will be reported up to 5 years.The primary economic outcome is cost effectiveness, measured as incremental cost per quality-adjusted life year gained over 52 weeks following index surgery. ETHICS AND DISSEMINATION: A favourable opinion was given by Wales REC 6 (16/WA/0156). Trial findings will be disseminated to patients, clinicians, commissioning groups and through peer reviewed publication. TRIAL REGISTRATION NUMBER: ISRCTN13930454.

Can venous cannula design influence venous return and negative pressure with a minimally invasive extracorporeal circulation?

INTRODUCTION: Recent advances to make cardiopulmonary bypass more physiological include the use of kinetic-assisted venous drainage but without a venous reservoir. Despite manipulation of intravascular volume and patient positioning, arterial flow is frequently reduced. Negative venous line pressures can be generated, which may elicit gaseous microemboli. We investigated the influence of venous cannula design on venous return and negative venous line pressures. METHODS: In a single-centre, single-surgeon, prospective, randomized, double-blind trial, 48 patients undergoing isolated coronary artery, aortic valve or combined coronary artery and aortic valve surgery, with a minimally invasive circuit, were randomized to a conventional two-stage (2S) or three-stage venous cannula (3S), or to a three-stage venous cannula with additional 'fenestrated' ridges (F3S). Blood flow, venous line pressures and gaseous microemboli number and size were measured. RESULTS: The pump flow achieved was the same between groups, but in each case fell below the target range of 2.2-2.4 L min-1 m-2. The three-stage cannula recorded significantly lower negative pressure than the other cannulae. The total count and volume of gaseous emboli detected with the F3S cannulae was very high in some cases, with wide heterogeneity. DISCUSSION: The low negative pressures recorded with three-stage cannula, despite having a larger drainage orifice area, suggest that negative pressure may be more influenced by lumen diameter and vena cava collapse rather than drainage hole size. The additional fenestrations resulted in flow characteristics and negative pressures similar to the larger two-stage cannula but are associated with generation of gaseous microemboli.

Transapical valve-in-ring mitral valve implantation through the anterior mitral valve leaflet.

Transcatheter mitral valve implantation (TMVI) is a relatively novel intervention used to replace the mitral valve of individuals deemed too high risk or unsuitable for surgery. It is associated with a number of specific risks, including left ventricular outflow tract obstruction (LVOTO).  In this video tutorial we present the case of a 75-year-old man who was unable to undergo redo surgical repair and had a number of risk factors for LVOTO. To minimize these risks, we deployed the TMVI within the anterior mitral valve leaflet. The postoperative result was mild mitral valve regurgitation and no LVOTO.  The long-term outcome of this approach is yet to be determined but we believe this technique offers a novel method to manage a select group of patients suffering with mitral valve disease and at risk of LVOTO.

Transapical valve-in-ring mitral valve implantation through the anterior mitral valve leaflet.

Transcatheter mitral valve implantation is a relatively novel intervention that replaces the mitral valve of individuals deemed too high-risk or unsuitable for surgery. It is associated with a number of specific risks, including left ventricular outflow tract obstruction. In this report, we present the case of a 75-year-old man who was unable to undergo redo surgical repair and had a number of risk factors for left ventricular outflow tract obstruction. To minimize this risk, we deployed transcatheter mitral valve implantation within the anterior mitral valve leaflet resulting in mild mitral valve regurgitation postoperatively and no left ventricular outflow tract obstruction. Long-term durability of this approach is yet to be determined, but we believe that this intervention adds to the armamentarium of the heart team.

Oxygen delivery during cardiopulmonary bypass (and renal outcome) using two systems of extracorporeal circulation: a retrospective review.

OBJECTIVES: To investigate the combined influence of blood flow and haemodilution with either a miniaturized (Mini-CPB) or a conventional cardiopulmonary bypass (C-CPB) circuit on average oxygen delivery during bypass. The influence of this on clinical outcome, particularly renal dysfunction after routine coronary artery bypass surgery (CABG), was measured. METHODS: Retrospective analysis in two groups of 160 patients based on the surgeon's preference for bypass circuit. We compared consecutive patients undergoing isolated CABG surgery by two surgeons using Mini-CPB with a matched cohort of patients, from the same period, undergoing isolated CABG surgery by four other surgeons using a C-CPB. No trial-related intervention occurred. Data on bypass circuit parameters and clinical outcomes were acquired from routinely collected data sources. RESULTS: Average cardiopulmonary bypass pump flow was significantly lower with Mini-CPB compared with C-CPB. Mini-CPB resulted in significantly less haemodilution. The resultant calculated average oxygen delivery provided by the two systems was the same. Percentage change in plasma creatinine was significantly and inversely related to the oxygen delivery during CPB. There was no difference in percentage change in plasma creatinine between groups. The risk of having Acute Kidney Injury Network (AKIN) score ≥ 1 increased 1% for every 1 ml min(-1) m(-2) decrease in oxygen delivery (P = 0.0001, OR 0.990, 95% CI 0.984-0.995). CONCLUSIONS: Despite aiming for the same target pump flow, periodic limitations of venous return to the pump resulted in a significant reduction in average flow delivered to the patient by Mini-CPB. Less haemodilution compensated for this reduction, so that the average oxygen delivery was the same. The association between oxygen delivery and postoperative change in plasma creatinine was evident in both groups. Further work to understand whether there is a particular cohort of patients who benefit (or are put at risk) by one method of CPB vs the other is warranted.

Minimal access aortic valve replacement using minimal extracorporeal circuit.

A minimal extracorporeal circuit has been shown to decrease the transfusion rate, cardiac and neurological damage in coronary surgery. We describe in detail a technique for minimal-access aortic valve replacement using a minimal extra-corporeal circuit, and provide surgical and perfusion tips to maintain antegrade perfusion and a clear surgical field.

Carbamazepine-related hyponatremia following cardiopulmonary bypass.

A 67-year-old man on long-term carbamazepine therapy underwent elective coronary artery bypass grafting. Following an initially uncomplicated recovery, he developed symptomatic hyponatremia. The symptoms and biochemical abnormality improved after gradual discontinuation of carbamazepine. We discuss the association between carbamazepine and hyponatremia and the causes of hyponatremia after cardiopulmonary bypass. Surgeons should consider stopping carbamazepine before operations with cardiopulmonary bypass.

Treatment of delayed rupture of the left ventricle after mitral valve replacement.

Rupture of the left ventricle following mitral valve replacement is a catastrophic complication with deadly consequences. We report here the case of a 75-year-old man who underwent elective mitral valve replacement for severe mitral regurgitation. Delayed type 1 rupture of the left ventricle developed 3 hours postoperatively in the intensive care unit. A salvaging maneuver was used, which gained time, allowing reoperation and successful intraventricular repair.

Tratamento da ruptura protraída do ventrículo esquerdo após troca de valva mitral / Treatment of delayed rupture of the left ventricle after mitral valve replacement

Rupture of the left ventricle following mitral valve replacement is a catastrophic complication with deadly consequences. We report here the case of a 75-year-old man who underwent elective mitral valve replacement for severe mitral regurgitation. Delayed type 1 rupture of the left ventricle developed 3 hours postoperatively in the intensive care unit. A salvaging maneuver was used, which gained time, allowing reoperation and successful intraventricular repair

An external, oversized, porous polyester stent reduces vein graft neointima formation, cholesterol concentration, and vascular cell adhesion molecule 1 expression in cholesterol-fed pigs.

BACKGROUND: Reducing neointima formation and atherosclerosis are key goals in preventing late vein graft failure. Although pharmacologic and mechanical solutions have been proposed, the demonstration that these influence both aspects of vein graft pathology have been lacking. Supporting grafts externally with an oversized, highly porous polyester stent dramatically reduces neointima formation in normocholesterolemic pigs. However, its effects in the presence of hypercholesterolemia are unknown. METHODS: We compared wall thickening, cholesterol concentration, foam-cell formation, and the expression of the leukocyte adhesion molecule vascular cell adhesion molecule 1 after 3 months in stented and unstented saphenous vein interposition grafts into the carotid arteries of pigs fed cholesterol to cause modest hypercholesterolemia (11.2 +/- 1.2 mmol/L). RESULTS: Stenting reduced neointima formation from 5.6 +/- 0.4 to 1.2 +/- 0.2 mm(2) (n = 7; P <.00002, paired t test) and graft cholesterol concentration from 4.7 +/- 1.2 to 2.1 +/- 1.3 mg/g wet weight (P <.02). Foam cells were observed in unstented grafts (mean, 1.5% +/- 0.5% of all cells) but never in stented grafts. Vascular cell adhesion molecule 1 was strongly expressed in 53% +/- 8% of intimal and medial cells in unstented grafts but was weakly expressed in only 19% +/- 3% (n = 4, P <.05) of stented grafts. CONCLUSIONS: We conclude that external stenting with polyester favorably influences both neointima formation and early atherosclerosis, both of which are key aspects of vein graft disease, and that decreased expression of vascular cell adhesion molecule 1 is part of the underlying mechanism.