Decreased incidence of low output syndrome with a switch from tepid to cold continuous minimally diluted blood cardioplegia in isolated coronary artery bypass grafting

Definitions of low cardiac output syndrome after cardiac surgery and their effect on the incidence of intraoperative LCOS: A literature review and cohort study

Objectives

Low cardiac output syndrome (LCOS) is a serious complication after cardiac surgery. Despite scientific interest in LCOS, there is no uniform definition used in current research and clinicians cannot properly compare different study findings. We aimed to collect the LCOS definitions used in literature and subsequently applied the definitions obtained to existing data to estimate their effect on the intraoperative LCOS incidences in adults, children and infants.

Design

This is a literature review, followed by a retrospective cohort study.

Setting

This is a single-institutional study from a university hospital in the Netherlands.

Participants

Patients from all ages undergoing cardiac surgery with cardiopulmonary bypass between June 2011 and August 2018.

Interventions

We obtained different definitions of LCOS used in the literature and applied these to data obtained from an anesthesia information management system to estimate intraoperative incidences of LCOS. We compared intraoperative incidences of LCOS in different populations based on age (infants, children and adults).

Measurements and main results

The literature search identified 262 LCOS definitions, that were applied to intraoperative data from 7,366 patients. Using the 10 most frequently published LCOS definitions, the obtained incidence estimates ranged from 0.4 to 82% in infants, from 0.6 to 56% in children and from 1.5 to 91% in adults.

Conclusion

There is an important variety in definitions used to describe LCOS. When applied to data obtained from clinical care, these different definitions resulted in large distribution of intraoperative LCOS incidence rates. We therefore advocate for standardization of the LCOS definition to improve clinical understanding and enable adequate comparison of outcomes and treatment effects both in daily care and in research.

Low cardiac output syndrome in the postoperative period of cardiac surgery. Profile, differences in clinical course and prognosis. The ESBAGA study

OBJECTIVES

An analysis is made of the clinical profile, evolution and differences in morbidity and mortality of low cardiac output syndrome (LCOS) in the postoperative period of cardiac surgery, according to the 3 diagnostic subgroups defined by the SEMICYUC Consensus 2012.

DESIGN

A multicenter, prospective cohort study was carried out.

SETTING

ICUs of Spanish hospitals with cardiac surgery.

PATIENTS

A consecutive sample of 2,070 cardiac surgery patients was included, with the analysis of 137 patients with LCOS.

INTERVENTIONS

No intervention was carried out.

RESULTS

The mean patient age was 68.3±9.3 years (65.2% males), with a EuroSCORE II of 9.99±13. NYHA functional class III-IV (52.9%), left ventricular ejection fraction<35% (33.6%), AMI (31.9%), severe PHT (21.7%), critical preoperative condition (18.8%), prior cardiac surgery (18.1%), PTCA/stent placement (16.7%). According to subgroups, 46 patients fulfilled hemodynamic criteria of LCOS (group A), 50 clinical criteria (group B), and the rest (n=41) presented cardiogenic shock (group C). Significant differences were observed over the evolutive course between the subgroups in terms of time subjected to mechanical ventilation (114.4, 135.4 and 180.3min in groups A, B and C, respectively; P<.001), renal replacement requirements (11.4, 14.6 and 36.6%; P=.007), multiorgan failure (16.7, 13 and 47.5%), and mortality (13.6, 12.5 and 35.9%; P=.01). The mean maximum lactate concentration was higher in cardiogenic shock patients (P=.002).

CONCLUSIONS

The clinical evolution of these patients leads to high morbidity and mortality. We found differences between the subgroups in terms of the postoperative clinical course and mortality.

Is microplegia really superior to standard blood cardioplegia? The results from a meta-analysis

Background:

Microplegia (whole blood cardioplegia with reduced volume) retains all the advantages of blood cardioplegia (such as superior oxygen-carrying capacity, better osmotic properties and antioxidant capability, etc.) without the potential disadvantages of hemodilution (such as myocardial edema). We sought to perform a systematic review and meta-analysis to compare microplegia and standard blood cardioplegia on the cardioprotective effects for patients undergoing coronary artery bypass grafting (CABG).

Methods:

MEDLINE, EMBASE and the Cochrane Central Register of Controlled Trials were searched for relevant controlled trials published in English, from their inception up to May 15th, 2013. Data on low output syndrome, spontaneous return to sinus rhythm, volume of cardioplegia and perioperative myocardial infarction were analyzed.

Results:

Five studies, totaling 296 patients, were included out of 77 retrieved citations. The microplegia group used less volume of cardioplegia (WMD, -514.79 ml, 95%CI: -705.37 ml to -324.21 ml) when compared with the standard blood cardioplegia group. There were no statistical differences in the incidence of low output syndrome (RR, 0.95, 95%CI: 0.55 to 1.62), spontaneous return to sinus rhythm (RR, 1.64, 95%CI: 0.61 to 4.41) and perioperative myocardial infarction (RR, 0.62, 95%CI: 0.19 to 2.08).

Conclusions:

Microplegia was associated with less volume of cardioplegia, whereas the incidence of spontaneous return to sinus rhythm and perioperative myocardial infarction were similar, but large controlled randomized trials are still needed to confirm this.

Does magnesium-supplemented cardioplegia reduce cardiac injury? A meta-analysis of randomized controlled trials

BACKGROUND

Magnesium is often used to supplement cardioplegic solutions during cardiopulmonary bypass due to its cardioprotective effect during ischemia and reperfusion. The aim of this meta-analysis was to evaluate the effects of magnesium-supplemented cardioplegia versus an inactive (placebo) control cardioplegia on reducing cardiac injury after cardiac arrest surgery, as found by randomized, controlled trials.

METHODS

The Medline, Cochrane Library, and Chinese literature databases (CJFD, CBM, CSJD, Wanfang) were comprehensively searched for reports of randomized, controlled trials (RCTs) evaluating magnesium-supplemented cardioplegic solutions. The clinical parameters and outcomes of interest were the incidence of postoperative low cardiac output, auto-rebeating rate, ICU stay length, new onset postoperative atrial fibrillation, peak value of CK-MB (and/or cTnI), incidence of myocardial infarction, and in-hospital mortality.

RESULTS

Ten trials, with a total of 1214 patients, were included. The frequency of low cardiac output, inotropic utilization, and myocardial infarction, as well as auto-rebeating rate, length of ICU stay and in-hospital mortality, were similar between the two groups. There was a marginal reduction in the incidence of new-onset postoperative atrial fibrillation in the magnesium-supplemented cardioplegia group.

CONCLUSIONS

The advantage of magnesium-supplemented cardioplegia, compared with cardioplegia without magnesium, remains unconvincing based on the current evidence. The decision to add magnesium to the cardioplegic solution to a patient undergoing cardiac arrest surgery should be carefully considered.

Is off-pump coronary artery bypass surgery superior to on-pump coronary artery bypass surgery on postoperative paradoxical ventricular septal motion?

BACKGROUND

The aims of this study were to investigate the appearance of paradoxical ventricular septal motion (PSM) after coronary artery bypass graft (CABG) surgery and to identify factors that might be related to this abnormality.

METHODS

This prospective study included 119 consecutive patients (38 women, 81 men) who underwent CABG. Patients who underwent on-pump surgery (22 women, 45 men) and patients who underwent off-pump surgery (16 women, 36 men) were studied separately. All subjects underwent preoperative angiographic septal perfusion evaluation, pre- and postoperative echocardiography, and standard electrocardiographic and laboratory investigations, including troponin I and CK-MB levels. Multivariate logistic regression analysis was also performed for a variety of related parameters.

RESULTS

Significant differences in EuroSCORE, length of intensive care unit stay, length of hospital stay, PSM (assessed using echocardiography), septal perfusion (observed using preoperative angiography), postoperative pleural effusion, and intensive care unit recidivism were observed between the two groups (P < .05). Moreover, postoperative PSM was correlated with septal perfusion (r = -0.687**, P < .001), type of operation (r = -0.194*, P = .035), diabetes mellitus (r = 0.273**, P = .003), carotid stenosis (r = 0.235*, P = .011), the number of distal anastomoses (r = 0.245**, P = .008), pleural effusion (r = 0.193*, P = .037), and intensive care unit recidivism (r = 0.249**, P = .007). However, multivariate analysis demonstrated that only preoperative septal perfusion (odds ratio: 0.037; 95% confidence interval: 0.011-0.128; P < .05) constitutes an independent risk factor for PSM (P < .05).

CONCLUSIONS

This study demonstrated that preoperative septal perfusion deficiency represents an independent risk factor for postoperative PSM in patients undergoing CABG. Further investigations addressing the timing of the appearance of PSM and the correlation of this finding with perfusion imaging studies may provide new details concerning the mechanisms that underlie this abnormality.