On-pump coronary surgery with and without cardioplegic arrest: comparison of inflammation, myocardial, cerebral and renal injury and early and late health outcome in a single-centre randomised controlled trial

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.

On-pump beating heart versus off-pump myocardial revascularization-a propensity-matched comparison

Objective

On-pump beating heart (OP-BH) coronary artery bypass grafting (CABG) is often undertaken as an alternative between off-pump coronary artery bypass (OPCAB) and conventional on-pump coronary artery bypass grafting (On-pump CABG), especially in India. However, outcome data following OP-BH surgery is sparse. The aim of this study was to compare the outcomes of OP-BH CABG with OPCAB.

Methods

From our institutional database, all patients undergoing OP-BH CABG (n = 531) were identified. A propensity-matched cohort undergoing OPCAB (n = 531) was identified from the database. Nearest neighbor matching technique was used and the groups were matched for variables including age, gender, body mass index, EuroSCORE, history of recent myocardial infarction or unstable angina, hypertension, peripheral vascular disease, chronic obstructive airway disease, diabetes, pre-op renal impairment, pre-op neurological events, and left ventricular function.

Results

The propensity-matched groups were well matched in terms of baseline characteristics. The mean EuroSCORE was 3.17 and 3.20 in the OP-BH and the OPCAB groups. The unadjusted 30-day mortality in the propensity-matched OPCAB group was 2.07% (11/531) while mortality in the on-pump beating heart group was significantly higher at 6.9% (37/531). Multivariate analysis showed that OP-BH CABG was an independent risk factor for 30-day mortality as well as major adverse post-operative outcomes including renal, neurological, and respiratory outcomes and post-operative atrial fibrillation.

Conclusions

OP-BH CABG is associated with worse clinical outcomes compared to patients undergoing OPCAB.

On-pump beating heart versus conventional on-pump coronary artery bypass grafting on clinical outcomes: a meta-analysis

Background

A hybrid surgery method, on-pump beating heart coronary artery bypass graft (ON-BH CABG), is supposed to be a promising technology for coronary artery revascularization. Here, we conducted a comprehensive meta-analysis of the data derived from published studies on ON-BH CABG and conventional on-pump coronary artery bypass graft (C-CABG) to compare their short-term and long-term clinical outcomes.

Methods

We searched major electronic databases and 24 studies incorporating 6,862 patients (1,847 ON-BH CABG and 5,015 C-CABG) were included eventually, and 9 studies of them were focusing on high-risk patients.

Results

Compared with ON-BH CABG, C-CABG was associated with a higher risk in early mortality [odds ratio (OR), 1.45; 95% confidence interval (CI), 1.09 to 1.93; P=0.01], myocardial infarction (MI) (OR, 2.60; 95% CI, 1.41 to 4.78; P<0.01), low output syndrome (LOS) (OR, 2.56; 95% CI, 1.55 to 4.23; P<0.01), renal failure (OR, 1.84; 95% CI, 1.38 to 2.44; P<0.01). In contrast, there was no significant difference in long-term survival [hazard ratio (HR), 1.08; 95% CI, 0.81 to 1.43; P=0.60]. In systematic analysis of the studies in high-risk patients, ON-BH CABG showed a lower risk in terms of early mortality, intra-aortic balloon pump (IABP) usage, renal failure, hemodialysis, MI and pulmonary complication. No significant difference was observed in the long-term survival between ON-BH CABG and C-CABG.

Conclusions

With experienced and adept surgical team and mature ON-BH technology, ON-BH CABG may reduce the risk of postoperative death and complications in some patients. It might be an attractive alternative for high-risk patient populations.

Impact of avoiding cardioplegic arrest on clinical outcome in patients undergoing CABG in Bangladesh: a systematic review and meta-analysis

Objectives

Over the last decade, the practice of surgical revascularization for the coronary artery disease has been popularized in Bangladesh. Our aim was to compare the outcome of non-cardioplegic versus cardioplegic coronary artery bypass surgery in terms of early postoperative outcomes.

Methods

A literature search was conducted in March 2020 on Medline (via PubMed), Scopus and Bangladesh Journal Online electronic databases according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. All randomized controlled trials and observational studies reporting findings of coronary revascularization surgery comparing the outcomes were included.

Results

Fifteen studies were used quantitatively that included a total cohort of 4750 coronary artery bypass graft (CABG) patients in Bangladesh. After the meta-analysis, we observed a longer duration of operating time [mean difference (MD): - 52.30, confidence interval (CI): - 67.73 to - 36.86, I ² 18 = 89%, p < 0.00001] and a higher incidence of postoperative atrial fibrillation [risk ratio (RR): 0.43, CI: 0.14 to 0.80, I ² = 44%, p = 0.01] in the cardioplegic CABG group as compared with the non-cardioplegic group. Additionally, statistically significant longer duration of ventilation time (MD: - 8.64, CI: - 9.47 to - 7.82, I ² = 82%, p < 0.00001) and ICU stay (MD: - 17.25, CI: - 33.36 to - 1.14, I ² = 99%, p = 0.04) was observed in the cardioplegic group. No significant differences in number of grafts and in-hospital mortality were found between the two groups.

Conclusion

Non-cardioplegic CABG may be a viable alternative to cardioplegic CABG in Bangladeshi population, providing similar postoperative outcomes but offering additional advantage of shorter operation and ventilation times.

On-pump beating-heart coronary artery bypass grafting in high-risk patients: A systematic review and meta-analysis

BACKGROUND

Operative technique for surgical myocardial revascularization in high-risk patients remains an argument of debate. On-pump coronary artery bypass graft (CABG) with cardioplegic arrest and off-pump CABG have intrinsic limitations. The hybrid approach of on-pump beating-heart CABG (OPBHC) has been proposed over the years with conflicting results. This systematic review and meta-analysis intends to summarize the contemporary literature.

METHODS

A literature search was conducted through major electronic databases. The systematic review provided a total of 279 articles, of those 17 studies were included in the present study.

RESULTS

Compared with on-pump CABG, OPBHC patients showed a preoperative higher risk profile but had reduced early mortality (risk ratio [RR], 0.59, 95% CI, 0.36-0.97) and reduced postoperative stroke (RR, 0.60, 95% CI, 0.39-0.91). Also, interesting trends towards reduced postoperative intra-aortic balloon pump use (RR, 0.56, 95% CI, 0.31-1.01) and myocardial infarction (RR, 0.48, 95% CI, 0.22-1.07) were observed. Baseline characteristics and postoperative complications were similar between OPBHC and off-pump CABG, but limited data are available. The risk of incomplete revascularization in OPBHC is lower than off-pump CABG (RR, 0.53, 95% CI, 0.33-0.87) but higher than conventional on-pump CABG (RR, 1.71, 95% CI, 1.23-2.39).

CONCLUSION

OPBHC is an effective technique to perform surgical revascularization in high-risk patients as preventing haemodynamic deterioration and guaranteeing adequate end-organ perfusion. OPBHC represents an alternative technique to on-pump and off-pump CABG, in those cases in which complications deriving from cardioplegic arrest or manipulation of the heart are more likely. For these reasons, OPBHC might be useful in patients with recent myocardial infarction or with left ventricular dysfunction.

Normoxic re-oxygenation ameliorates end-organ injury after cardiopulmonary bypass

Background

In a rabbit model of cardiopulmonary bypass (CPB) and cardioplegic arrest, we previously showed that hyperoxic myocardial reperfusion was associated with increased left ventricular (LV) systolic dysfunction and myocardial injury compared with normoxic reperfusion. The aim of this study was to evaluate in our experimental model the impact of post-CPB reperfusion conditions on other organs potentially vulnerable to ischemic injury such as the brain and kidney.

Methods

After 60 min of CPB, aortic cross-clamp, and cold cardioplegic arrest, rabbits were reperfused under hyperoxic or normoxic conditions for 120 min. Left ventricular systolic contractility (LV + dP/dt) and diastolic relaxation (LV –dP/dt) were continuously recorded, and end-organ injury was assessed by measuring circulating biomarkers specific for kidney (cystatin C and creatinine) and brain injury [S100B and neuron specific enolase (NSE)]. At completion of the protocol, kidney and brain tissues were harvested for measuring oxidant stress (OS), inflammation and apoptosis.

Results

Following aortic cross-clamp removal, rabbits exposed to normoxic reperfusion demonstrated preserved LV systolic and diastolic function compared with hyperoxic reperfusion (LV + dP/dt: 70 ± 14% of pre-CPB vs. 36 ± 21%, p = 0.018; LV -dP/dt: 72 ± 36% of pre-CPB vs. 33 ± 20%, p = 0.023). Similarly, CPB increased plasma creatinine, S100B and NSE that were significantly attenuated by normoxic reperfusion compared with hyperoxic reperfusion (creatinine: 4.0 ± 0.5 vs. 7.1 ± 0.8 mg/dL, p = 0.004; S100B: 4.0 ± 0.8 vs. 6.7 ± 1.0 ng/mL, p = 0.047; NSE: 57.7 ± 6.8 vs. 101.3 ± 16.1 pg/mL, p = 0.040). Furthermore, both kidney and brain tissues showed increased mRNA expression and activation of pathways for OS, inflammation, and apoptosis, that were reduced under normoxic compared with hyperoxic conditions.

Conclusions

Normoxic reperfusion ameliorates cardiac, renal and neural injury compared with hyperoxic reperfusion in an in vivo animal model of CPB and cardioplegic arrest. This protective effect of normoxic reperfusion may be due to a reduction in signaling pathways for OS, inflammation, and apoptosis.

Emergency surgery for left main disease: with and without cardioplegic arrest

BACKGROUND

The aims of this study were to evaluate the on-pump beating-heart technique of coronary artery bypass in patients with acute myocardial infarction and left main disease, and to retrospectively compare the early postoperative results with those of conventional on-pump arrested-heart coronary surgery.

METHODS

Eighty-five patients with acute myocardial infarction caused by left main disease, who underwent emergency surgery between January 1998 and April 2017 at Saiseikai Utsunomiya Hospital, were enrolled in this study. Of these patients, 56 were evaluated using propensity-matched analysis. The patients were divided into two groups according to the surgical procedure: group A ( n = 28) had on-pump surgery on the arrested heart, and group B ( n = 28) had on-pump surgery on the beating heart. Early postoperative results were compared between the two groups.

RESULTS

Preoperative and intraoperative characteristics showed no significant differences between the two groups. The peak creatine kinase myocardial band level was significantly lower in group B (group A 151 vs. group B 91 IU·L^-1, p = 0.01). The early mortality rate was higher in group A than group B, but the difference was not significant (group A 28.6% vs. group B 17.9%, p = 0.53).

CONCLUSIONS

There was no significant advantage based on surgical procedure between on-pump beating-heart surgery and on-pump surgery on the arrested heart. On-pump beating-heart coronary artery bypass grafting significantly reduced the peak creatine kinase myocardial band level, but there were no significant differences in the early postoperative data, including the mortality rate and left ventricular function.

Shortening cardioplegic arrest time in patients undergoing combined coronary and valve surgery: results from a multicentre randomized controlled trial: the SCAT trial

OBJECTIVES

Combined coronary artery bypass grafting and valve surgery requires a prolonged period of cardioplegic arrest (CA) predisposing to myocardial injury and postoperative cardiac-specific complications. The aim of this trial was to reduce the CA time in patients undergoing combined coronary artery bypass grafting and valve surgery and assess if this was associated with less myocardial injury and related complications.

METHODS

Participants were randomized to (i) coronary artery bypass grafting performed on the beating heart with cardiopulmonary bypass support followed by CA for the valve procedure (hybrid) or (ii) both procedures under CA (conventional). To assess complications related to myocardial injury, we used the composite of death, myocardial infarction, arrhythmia, need for pacing or inotropes for >12 h. To assess myocardial injury, we used serial plasma troponin T and markers of metabolic stress in myocardial biopsies.

RESULTS

Hundred and sixty patients (80 hybrid and 80 conventional) were randomized. Mean age was 66.5 years and 74% were male. Valve procedures included aortic (61.8%) and mitral (33.1%) alone or in combination (5.1%). CA time was 16% lower in the hybrid group [median 98 vs 89 min, geometric mean ratio (GMR) 0.84, 95% confidence interval (CI) 0.77-0.93, P  = 0.0004]. Complications related to myocardial injury occurred in 131/160 patients (64/80 conventional, 67/80 hybrid), odds ratio 1.24, 95% CI 0.54-2.86, P  = 0.61. Release of troponin T was similar between groups (GMR 1.04, 95% CI 0.87-1.24, P  = 0.68). Adenosine monophosphate was 28% lower in the hybrid group (GMR 0.72, 95% CI 0.51-1.02, P  = 0.056).

CONCLUSIONS

The hybrid procedure reduced the CA time but myocardial injury outcomes were not superior to conventional approach.

TRIAL REGISTRATION

ISRCTN65770930.

Myocardial protection following del Nido cardioplegia in pediatric cardiac surgery

Background

This study was designed to compare myocardial protection with del Nido cardioplegia and conventional blood cardioplegia in children undergoing cardiac surgery in Risk Adjustment for Congenital Heart Surgery categories 1 and 2.

Methods

Sixty patients were randomized into 2 groups receiving del Nido cardioplegia solution or conventional blood cardioplegia. Myocardial injury was assessed using biochemical markers (troponin I and creatine kinase-MB). Vasoactive-inotropic scores were calculated to compare inotropic requirements.

Results

Demographic characteristics, cardiopulmonary bypass time, and aortic crossclamp time were comparable in the 2 groups. Time-related changes in troponin I and creatine kinase-MB were similar in both groups. Statistically significant differences were seen in total cardioplegia volume requirement ( p < 0.0001), number of cardioplegia doses given ( p < 0.0001), packed red cell volume usage during cardiopulmonary bypass ( p < 0.02), and time taken to restore spontaneous regular rhythm ( p < 0.0001). Vasoactive-inotropic scores on transfer to the intensive care unit ( p < 0.040) and at 24 h ( p < 0.030) were significantly lower in the del Nido group. Duration of mechanical ventilation, intensive care unit stay, and hospital stay were comparable in the 2 groups.

Conclusions

Our results show that del Nido cardioplegia solution is as safe as conventional blood cardioplegia. Moreover, it provides the benefits of reduced dose requirement, lower consumption of allogenic blood on cardiopulmonary bypass, quicker resumption of spontaneous regular cardiac rhythm, and less inotropic support requirement on transfer to the intensive care unit and at 24 h, compared to conventional blood cardioplegia.

Attenuated recovery of contractile function in aging hearts following global ischemia/reperfusion: Role of extracellular HSP27 and TLR4

BACKGROUND

While cardiac functional recovery is attenuated in the elderly following cardiac surgery with obligatory global myocardial ischemia/reperfusion (I/R), the underlying mechanism remains incompletely understood. We observed previously that human and mouse myocardium releases heat shock protein (HSP) 27 during global I/R. Extracellular HSP27 induces myocardial inflammatory response and plays a role in post-ischemic cardiac dysfunction in adult mouse hearts.

OBJECTIVE

This study was to determine the role of extracellular HSP27 and Toll-like receptor 4 (TLR4) in the attenuated functional recovery in aging mouse hearts following global I/R.

METHODS AND RESULTS

Hearts isolated from aging (18-24 months) and adult (4-6 months) mice were subjected to ex vivo global I/R. Augmented release of HSP27 in aging hearts is associated with greater production of cytokines (TNF-α and IL-1β) and worse functional recovery. Anti-HSP27 suppressed the inflammatory response and markedly improved functional recovery in aging hearts. Perfusion of recombinant HSP27 to aging hearts resulted in greater cytokine production and more severe contractile depression in comparison to adult hearts. TLR4 deficiency abolished cytokine production and functional injury in aging hearts exposed to recombinant HSP27. Interestingly, aging hearts had higher TLR4 protein levels and displayed enhanced TLR4-mediated NF-κB activation following HSP27 stimulation or I/R.

CONCLUSION

Extracellular HSP27 and TLR4 jointly enhance the inflammatory response and hamper functional recovery following I/R in aging hearts. The enhanced inflammatory response to global I/R and attenuated post-ischemic functional recovery in aging hearts is due, at least in part, to augmented myocardial release of HSP27 and elevated myocardial TLR4 levels.