Comparison of the use of minimized cardiopulmonary bypass with conventional techniques on the incidence of retinal microemboli during aortic valve replacement surgery

Early effects of cardiopulmonary bypass surgery on retinal nerve fiber layer and ganglion cell layer

PURPOSE

To determine the effects of cardiopulmonary bypass surgery on retinal nerve fiber layer, ganglion cell layer, and macula by optic coherens tomography (OCT).

METHOD

Sixty-six eyes of 33 patients aged between 44 and 74 who were indicated for cardiopulmonary bypass surgery in the cardiovascular surgery clinic were included in the study. Routine ophthalmologic examinations of all patients were performed before and 1 week after surgery. In addition, 3D(H) Macula+5 Line Cross 12 × 9 mm mod and Peripapilar 3D Disk 6 × 6 mm mod data were analyzed with OCT (Topcon, Triton Swept Source-OKT, Tokyo, Japan) device. Peripapillary total, superior, inferior retinal nerve fiber layer (RNFL), optic disc cavity volume, cup-to-disc ratio, macular ganglion cell layer (GCL), macular thickness were compared before and after surgery.

RESULTS

After cardiopulmonary bypass surgery, thickening was detected in the total RNFL (p<0.001), superior RNFL (p = 0.01) and inferior RNFL (p<0.001) layers. There was no change in the values of GCL, macular thickness, optic disc cupping volume, cup-to-disc ratio after surgery (p>0.05). There was a positive correlation (r = 0.392 p<0.05) between the patients' blood oxygen (PO2) values during bypass surgery with their post-surgical GCL+ values, and a negative correlation between optic disc cup volumes (r=-0.349 p<0.05).

CONCLUSION

RNFL thickening has been detected in patients undergoing cardiopulmonary bypass surgery. This thickening may occur secondary to ischemic edema that occurs during surgery. Considering the late complications of ischemic edema in the RNFL, oxygen levels should be kept at an optimum level during surgery and long-term ophthalmologic follow-ups should be performed.

Effects of interventions targeting the systemic inflammatory response to cardiac surgery on clinical outcomes in adults

BACKGROUND

Organ injury is a common and severe complication of cardiac surgery that contributes to the majority of deaths. There are no effective treatment or prevention strategies. It has been suggested that innate immune system activation may have a causal role in organ injury. A wide range of organ protection interventions targeting the innate immune response have been evaluated in randomised controlled trials (RCTs) in adult cardiac surgery patients, with inconsistent results in terms of effectiveness.

OBJECTIVES

The aim of the review was to summarise the results of RCTs of organ protection interventions targeting the innate immune response in adult cardiac surgery. The review considered whether the interventions had a treatment effect on inflammation, important clinical outcomes, or both.

SEARCH METHODS

CENTRAL, MEDLINE, Embase, conference proceedings and two trial registers were searched on October 2022 together with reference checking to identify additional studies.

SELECTION CRITERIA

RCTs comparing organ protection interventions targeting the innate immune response versus placebo or no treatment in adult patients undergoing cardiac surgery where the treatment effect on innate immune activation and on clinical outcomes of interest were reported.

DATA COLLECTION AND ANALYSIS

Searches, study selection, quality assessment, and data extractions were performed independently by pairs of authors. The primary inflammation outcomes were peak IL-6 and IL-8 concentrations in blood post-surgery. The primary clinical outcome was in-hospital or 30-day mortality. Treatment effects were expressed as risk ratios (RR) and standardised mean difference (SMD) with 95% confidence intervals (CI). Meta-analyses were performed using random effects models, and heterogeneity was assessed using I2.

MAIN RESULTS

A total of 40,255 participants from 328 RCTs were included in the synthesis. The effects of treatments on IL-6 (SMD -0.77, 95% CI -0.97 to -0.58, I2 = 92%) and IL-8 (SMD -0.92, 95% CI -1.20 to -0.65, I2 = 91%) were unclear due to heterogeneity. Heterogeneity for inflammation outcomes persisted across multiple sensitivity and moderator analyses. The pooled treatment effect for in-hospital or 30-day mortality was RR 0.78, 95% CI 0.68 to 0.91, I2 = 0%, suggesting a significant clinical benefit. There was little or no treatment effect on mortality when analyses were restricted to studies at low risk of bias. Post hoc analyses failed to demonstrate consistent treatment effects on inflammation and clinical outcomes. Levels of certainty for pooled treatment effects on the primary outcomes were very low.

AUTHORS' CONCLUSIONS

A systematic review of RCTs of organ protection interventions targeting innate immune system activation did not resolve uncertainty as to the effectiveness of these treatments, or the role of innate immunity in organ injury following cardiac surgery.

Assessment of Retinal Capillary Dropout after Transcatheter Aortic Valve Implantation by Optical Coherence Tomography Angiography

Transcatheter aortic valve implantation (TAVI) is an alternative to open heart surgery in the treatment of symptomatic aortic valve stenosis, which is often the treatment of choice in elderly and frail patients. It carries a risk of embolic complications in the whole cerebral vascular bed, which includes the retinal vasculature. The main objective was the evaluation of retinal emboli visible on optical coherence tomography angiography (OCTA) following TAVI. This is a prospective, single center, observational study enrolling consecutive patients over two years. Patients were assessed pre- and post-TAVI. Twenty-eight patients were included in the final analysis, 82.1% were male, median age was 79.5 (range 52–88), median BCVA was 82.5 letters (range 75–93). Eight patients (28.6%) presented new capillary dropout lesions in their post-TAVI OCTA scans. There was no statistically significant change in BCVA. Quantitative analysis of macular or peripapillary OCTA parameters did not show any statistically significant difference in pre- and post-intervention. In conclusion, capillary dropout lesions could frequently be found in patients after TAVI. Quantitative measurements of macular and peripapillary flow remained stable, possibly indicating effective ocular blood flow regulation within the range of left ventricular ejection fraction in our cohort.

Conventional versus miniaturized cardiopulmonary bypass: A systematic review and meta-analysis

Objective

A meta-analysis of randomized controlled trials was performed to compare the effects of miniaturized extracorporeal circulation (MECC) and conventional extracorporeal circulation (CECC) on morbidity and mortality rates after cardiac surgery.

Methods

A comprehensive literature search was conducted using Ovid, PubMed, Medline, EMBASE, and the Cochrane databases. Randomized controlled trials from the year 2000 with n > 40 patients were considered. Key search terms included variations of “mini,” “cardiopulmonary,” “bypass,” “extracorporeal,” “perfusion,” and “circuit.” Studies were assessed for bias using the Cochrane Risk of Bias tool. The primary outcomes were postoperative mortality and stroke. Secondary outcomes included arrhythmia, myocardial infarction, renal failure, blood loss, and a composite outcome comprised of mortality, stroke, myocardial infarction and renal failure. Duration of intensive care unit, and hospital stay was also recorded.

Results

The 42 studies eligible for this study included a total of 2154 patients who underwent CECC and 2196 patients who underwent MECC. There were no significant differences in any preoperative or demographic characteristics. Compared with CECC, MECC did not reduce the incidence of mortality, stroke, myocardial infarction, and renal failure but did significantly decrease the composite of these outcomes (odds ratio, 0.64; 95% confidence interval [CI], 0.50-0.81; P = .0002). MECC was also associated with reductions in arrhythmia (odds ratio, 0.67; 95% CI, 0.54-0.83; P = .0003), blood loss (mean difference [MD], –96.37 mL; 95% CI, –152.70 to –40.05 mL; P = .0008), hospital stay (MD, –0.70 days; 95% CI, –1.21 to –0.20 days; P = .006), and intensive care unit stay (MD, –2.27 hours; 95% CI, –3.03 to –1.50 hours; P < .001).

Conclusions

MECC demonstrates clinical benefits compared with CECC. Further studies are required to perform a cost–utility analysis and to assess the long-term outcomes of MECC. These should use standardized definitions of endpoints such as mortality and renal failure to reduce inconsistency in outcome reporting.

Aortic valve replacement with or without myocardial revascularization in octogenarians. Can minimally invasive extracorporeal circuits improve the outcome?

OBJECTIVE

The positive impact of minimally invasive extracorporeal circuits (MiECC) on patient outcome is expected to be most evident in patients with limited physiologic reserves. Nevertheless, most studies have limited their use to low-risk patients undergoing myocardial revascularization. As such, there is little evidence to their benefit outside this patient population. We, therefore, set out to explore their potential benefit in octogenarians undergoing aortic valve replacement (AVR) with or without concomitant myocardial revascularization.

METHODS

Based on the type of the utilized ECC, we performed a retrospective propensity score-matched comparison among all octogenarians (n = 218) who received a primary AVR with or without concomitant coronary artery bypass grafting in our institution between 2003 and 2010.

RESULTS

A MiECC was utilized in 32% of the patients. The propensity score matching yielded 52 matched pairs. The 30-day postoperative mortality (2% vs. 10%; p=0.2), the incidence of low cardiac output (0% vs. 6%; p=0.2) and the Intensive Care Unit (ICU) stay (2.5 ± 2.6 vs. 3.8 ± 4.7 days; p=0.06) were all in favour of the MiECC group, but failed to reach statistical significance while the 90-day postoperative mortality did (2% vs. 16%; p=0.02).

CONCLUSION

MiECCs have a positive influence on the outcome of octogenarians undergoing AVR with or without concomitant coronary artery bypass grafting. Their use should, therefore, be extended beyond isolated coronary artery bypass graft (CABG) surgery.

Retinal arterial blood flow and retinal changes in patients with sepsis: preliminary study using fluorescein angiography

Background

Although tissue perfusion is often decreased in patients with sepsis, the relationship between macrohemodynamics and microcirculatory blood flow is poorly understood. We hypothesized that alterations in retinal blood flow visualized by angiography may be related to macrohemodynamics, inflammatory mediators, and retinal microcirculatory changes.

Methods

Retinal fluorescein angiography was performed twice during the first 5 days in the intensive care unit to observe retinal abnormalities in patients with sepsis. Retinal changes were documented by hyperfluorescence angiography; retinal blood flow was measured as retinal arterial filling time (RAFT); and intraocular pressure was determined. In the analyses, we used the RAFT measured from the eye with worse microvascular retinal changes. Blood samples for inflammation and cerebral biomarkers were collected, and macrohemodynamics were monitored. RAFT was categorized as prolonged if it was more than 8.3 seconds.

Results

Of 31 patients, 29 (93%) were in septic shock, 30 (97%) required mechanical ventilation, 22 (71%) developed delirium, and 16 (51.6%) had retinal angiopathies, 75% of which were bilateral. Patients with prolonged RAFT had a lower cardiac index before (2.1 L/kg/m² vs. 3.1 L/kg/m², P = 0.042) and during angiography (2.1 L/kg/m² vs. 2.6 L/kg/m², P = 0.039). They more frequently had retinal changes (81% vs. 20%, P = 0.001) and higher intraocular pressure (18 mmHg vs. 14 mmHg, P = 0.031). Patients with prolonged RAFT had lower C-reactive protein (139 mg/L vs. 254 mg/L, P = 0.011) and interleukin-6 (39 pg/ml vs. 101 pg/ml, P < 0.001) than those with shorter RAFT.

Conclusions

Retinal angiopathic changes were more frequent and cardiac index was lower in patients with prolonged RAFT, whereas patients with shorter filling times had higher levels of inflammatory markers.

A Meta-Analysis of Miniaturized Versus Conventional Extracorporeal Circulation in Valve Surgery

The effects of miniaturized extracorporeal circulation in patients operated on for heart valve surgery are still inconsistent. We performed a meta-analysis of eight studies involving 1,011 patients to evaluate the comprehensive effects of miniaturized extracorporeal circulation. The results suggested its application significantly reduced the length of stay in the intensive care unit and total hospital stay after heart valve surgery, but no significant effects on reducing postoperative morbidity and mortality were observed. Further studies with long-term follow-up are needed to confirm our results.

Miniaturized cardiopulmonary bypass in adult cardiac surgery: a clinical update

INTRODUCTION

Cardiopulmonary bypass has undoubtedly been the cornerstone in the rapid development of cardiac surgery, allowing even the performance of procedures beyond the scope of cardiothoracic surgery. Its use however, is associated with significant complications that arise from the mechanical effects of the circuit on circulating blood components as well as the contact of blood with non-endothelial surfaces. Miniature cardiopulmonary bypass systems have been developed in an attempt to minimize these complications. Areas covered: Herein clinical outcomes from the most recent studies in adult cardiac surgery are discussed. The main benefits of miniaturisation as well as potential areas of further application are described. Expert commentary: Data is critically appraised in the context of current guidelines. Finally the need for further basic science in addition to large multi-centre randomized controlled trial data is highlighted.

What We have Learned about Minimized Extracorporeal Circulation versus Conventional Extracorporeal Circulation: An Updated Meta-Analysis

Introduction

The benefits of minimized extracorporeal circulation (MECC) compared with conventional extracorporeal circulation (CECC) are still in debate.

Methods

PubMed, EMBASE and the Cochrane Library were searched until November 10, 2014. After quality assessment, we chose a fixed-effects model when the trials showed low heterogeneity, otherwise a random-effects model was used. We performed univariate meta-regression and sensitivity analysis to search for the potential sources of heterogeneity. Cumulative meta-analysis was performed to access the evolution of outcome over time.

Results

41 RCTs enrolling 3744 patients were included after independent article review by 2 authors. MECC significantly reduced atrial fibrillation (RR, 0.76; 95% CI, 0.66 to 0.89; P<0.001; I2 = 0%), and myocardial infarction (RR, 0.43; 95% CI, 0.26 to 0.71; P = 0.001; I2 = 0%). In addition, the results regarding chest tube drainage, transfusion rate, blood loss, red blood cell transfusion volume, and platelet count favored MECC as well.

Conclusions

MECC diminished morbidity of cardiovascular complications postoperatively, conserved blood cells, and reduced allogeneic blood transfusion.

Feasibility of mitral valve surgery using minimal extracorporeal circulation

AIM

Using minimal extracorporeal circulation (MECC) in isolated coronary artery bypass grafting or aortic valve replacement has been proven to be safe, feasible and superior compared to standard cardiopulmonary bypass (CPB) in terms of postoperative complications, total hospital stay and blood product transfusions. This feasibility study evaluates the clinical outcomes of mitral valve surgery performed with MECC.

METHODS

From March 2006 to January 2011, seventy-five patients who underwent mitral valve surgery performed with MECC (n=75) in our institution were retrospectively evaluated. Demographic characteristics, operative data and clinical outcomes were collected in a prospectively designed database.

RESULTS

The mean age was 68.8 ± 10.2 years with a EuroSCORE of 7.0 ± 2.3. Thirty-seven patients had a moderate left ventricular function (with a range of 30-40%). All patients except two had severe mitral valve incompetence (MI). Surgery was successful in all procedures. The mean duration of surgery was 210 ± 44 min (range 118-356 min). The mean CPB time was 128 ± 30 (range 67-249) min. The cross-clamp time was 99 ± 26 (range 48-205) min. There were no intraoperative perfusion problems or airlocks reported. The mean intensive care unit (ICU) length of stay was two days. Subsequent analysis showed a first postoperative haemoglobin value of 9.4 g/dL ± 1.7. There were no peroperative neurological complications. One patient developed an ischaemic cerebrovascular accident (CVA) on the forth postoperative day due to inadequate anticoagulation. Other postoperative complications included eight patients with pneumonia, one superficial wound infection, temporary renal insufficiency in two patients and four patients needed re-exploration for excessive postoperative leakage. Overall in-hospital mortality was four percent.

CONCLUSION

Our results show, for the first time, that isolated or combined mitral valve surgery using MECC is feasible and safe.