Clinical practices for defining, detecting, and diagnosing postoperative atrial fibrillation after coronary revascularization surgery - A scoping review

OBJECTIVES

This scoping review was undertaken to understand the degree of variation in clinical practices associated with postoperative atrial fibrillation (POAF), following coronary revascularization surgery by collating and synthesising key concepts from current published literature.

REVIEW METHODS AND DATA SOURCES

This scoping review was conducted following the framework outlined by Askey and O'Malley. Reporting of this scoping review follows the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews checklist. Initial searches were completed in September 2020 and updated in January 2023. Comprehensive searches to identify relevant published literature were carried out within CINAHL, MEDLINE, and ProQuest databases. All searches were limited to full-text papers published in English with human adult participants. Deductive content analysis using NVivo software was performed to synthesise the data.

RESULTS

A total of 692 studies were identified during the database searches. After the deletion of duplicates and the application of the inclusion and exclusion criteria, 73 studies were included in the scoping review. The included studies were published between 2001 and 2022 and included a total of 24,833 participants. Forty-six studies included a definition of POAF, with four of these citing a peak-body definition. A total of 24 included studies reported on electrocardiogram diagnostic criteria for POAF, with 13/24 [54%] describing these characteristics within their definition. The time-based diagnostic criteria ranged from a minimum duration of greater than 30 seconds to greater than 1 hour. The most frequently reported minimum-time thresholds were ≥30 seconds, reported in 12 of 51 (24%) studies and ≥5 min, reported in 13 of 51 (25%) studies.

CONCLUSIONS

There is a lack of consistency in clinical practice for defining, detecting, and diagnosing POAF, following coronary revascularization surgery. Consensus and standardisation of clinical practices are urgently needed.

Outcomes of Coronary Artery Bypass Graft Surgery in Africa: A Systematic Review and Meta-Analysis

Coronary artery bypass graft (CABG) surgery has been in practice for many decades, and it is one of the most commonly performed cardiac surgeries worldwide. While there are several studies reporting data on perioperative outcomes following CABG in developed countries, there is a staggering paucity of data and evidence reporting the outcomes in developing areas such as Africa. Thus, it is important to study the practice and outcome of CABG in Africa to establish its clinical efficacy and safety in this region and identify factors that might be limiting its practice. The overall aim of this study is to identify all relevant clinical data on CABG in Africa and report on the perioperative outcomes and practice of CABG in the African population. Electronic search was performed using three online databases, PubMed, African Journal Online, and Research Gate, from inception to June 2023. The preferred reporting items for systematic reviews and meta-analysis (PRISMA) guideline was utilised for this study. Relevant studies fulfilling predefined eligibility criteria were included in the study. Intraoperative details, such as the number of grafts performed, operative, bypass, and cross-clamp time, were reported. The primary endpoint assessed were early mortality and overall mortality. The secondary endpoints included length of hospital stay, intensive care unit stay, and postoperative complications, such as renal impairment, atrial fibrillation, and surgical site infection. The data were pooled together and meta-analyzed using a random effect model for proportions and mean for meta-analysis with R software (version 4.3.1 (2023-06-16); R Development Core Team, Vienna, Austria). This systematic review identified 42 studies that fulfilled the study eligibility criteria, including 21 randomised controlled trials, 20 observational studies, and one cross-sectional study. Only four out of the 54 countries in Africa had studies carried out that met the criteria for this review; they included Algeria, Egypt, Nigeria, and South Africa, with a majority from Egypt. Meta-analysis reported a pooled early mortality and pooled overall mortality of 3.51% and 3.73%, respectively, for the total cohort of patients. The result of this meta-analysis suggests that mortality outcomes following CABG in Africa are relatively higher than those in developed nations. Several issues, such as lack of financial resources and poor infrastructure, continue to hinder the optimal practice of CABG procedures in many parts of Africa. Further studies focused on finding factors associated with outcomes following CABG should be done. Though there were a few limitations to the study largely from a lack of data from several regions and countries in Africa, the result from this meta-analysis can serve as a benchmark for future studies until more relevant data are reported.

Association of Preoperative Renin-Angiotensin System Inhibitors With Prevention of Postoperative Atrial Fibrillation and Adverse Events: A Systematic Review and Meta-analysis

IMPORTANCE

Postoperative atrial fibrillation (POAF) is a well-known complication after cardiac surgery. Renin-angiotensin system inhibitors (RASIs) have been suggested as an upstream therapy for selected patients with AF; however, evidence in the surgical setting is limited.

OBJECTIVE

To evaluate the role of preoperative RASIs in prevention of POAF and adverse events for patients undergoing cardiac surgery.

DATA SOURCES

The PubMed database and the Cochrane Library from inception until December 31, 2018, were searched by using the keywords renin-angiotensin system inhibitors OR angiotensin-converting enzyme inhibitors OR angiotensin receptor blocker OR aldosterone antagonist AND cardiac surgery. ClinicalTrials.gov was searched from inception until December 31, 2018, by using the keywords postoperative atrial fibrillation.

STUDY SELECTION

Randomized clinical trials (RCTs) and observational studies comparing the association between preoperative RASI treatment vs no preoperative RASI treatment (control group) and the incidence of POAF were identified. Eleven unique studies met the selection criteria.

DATA EXTRACTION AND SYNTHESIS

Pooled analysis was performed using a random-effects model. Sensitivity and subgroup analyses of RCTs were performed to test the stability of the overall effect. Metaregression was conducted to explore potential risk of bias.

MAIN OUTCOMES AND MEASURES

The primary outcome was POAF, and the secondary outcomes included rates of stroke and mortality and duration of hospitalization.

RESULTS

Eleven unique studies involving 27 885 unique patients (74.4% male; median age, 65 years [range, 58.5-74.5 years]) were included. Compared with the control group, the RASI group did not have a significantly reduced risk of POAF (odds ratio [OR], 1.04; 95% CI, 0.91-1.19; P = .55; z = 0.60), stroke (OR, 0.86; 95% CI, 0.62-1.19; P = .37; z = 0.90; without significant heterogeneity, P = .11), death (OR, 1.07; 95% CI, 0.85-1.35; P = .56; z = 0.59; without significant heterogeneity, P = .12), composite adverse cardiac events (OR, 1.04; 95% CI, 0.91-1.18; P = .58; z = 0.56), or a reduced hospital stay (weighted mean difference, -0.04; 95% CI, -1.05 to 0.98; P = .94; z = 0.07) using a random-effects model. Pooled analysis focusing on RCTs showed consistent results. The primary overall effect was maintained in sensitivity and subgroup analyses. Metaregression showed that male sex was significantly associated with POAF (τ2 = 0.0065; z = 3.47; Q = 12.047; P < .001) and that use of β-blockers was associated with a significantly reduced risk in developing POAF (τ2 = 0.018; z = -2.24; Q = 5.0091; P = .03).

CONCLUSIONS AND RELEVANCE

The findings from this study suggest that preoperative RASI treatment does not offer additional benefit in reducing the risk of POAF, stroke, death, and hospitalization in the setting of cardiac surgery. The results provide no support for conventional use of RASIs for the possible prevention of POAF and adverse events in patients undergoing cardiac surgery; further randomized data, particularly among those patients with heart failure, are needed.

Postoperative Atrial Fibrillation: Year 2011 Review of Predictive and Preventative Factors of Atrial Fibrillation Post Cardiac Surgery

Background: Post cardiac surgery atrial fibrillation is common after cardiac surgery. Despite the advances in medical and surgical treatment, its incidence remains high and unchanged for decades. The aim of this review was to summarize studies published in 2011 on identifying factors, prevention strategies, treatment and effect of post operative atrial fibrillation (POAF) on the outcome after cardiac surgery. Methods: A review was performed on Medline, Embase and Chocrane on all of the English-language, peer-reviewed published clinical studies on POAF; studies investigating the mechanism of developing POAF, prevention, treatment and outcome were all included and analyzed. Case reports, studies on persistent/preoperative atrial fibrillation (AF), POAF after cardiac transplant, congenital cases and nonclinical studies were all excluded. We have also valuated these studies based on the type of the study, their originality, impact factor of the journal and their limitations. Results: Overall 62 studies were reviewed and analyzed; 26 on POAF predictive factors, 31 on preventative strategies and 6 on the outcome of POAF. Of these studies only two were original and the remaining were either performed in AF in general population (n=10) or had been studied and reported several times before in cardiac surgery (n=50). The average impact factor of the journals that POAF was published in was only 2.8 ranging between 0.5 and 14.5. Conclusion: Post cardiac surgery atrial fibrillation is a multi-factorial and complex condition. Cardiac surgery may be a risk factor for developing POAF in patients already susceptible to this condition and may not be a complication of cardiac surgery. Future studies should mainly focus on histological changes in the conductive tissue of atrium and related treatment strategies rather than predictive factors of POAF and more funding should be made available to study this condition from new and entirely different perspectives.

Candesartan antagonizes pressure overload-evoked cardiac remodeling through Smad7 gene-dependent MMP-9 suppression

The present study was designed to investigate the underlying molecular mechanism for Angiotensin II type 1 receptor blockers (ARBs) mediated cardio-protection against pressure overload-induced cardiac remodeling with a focus on Smad7. ROCK-1, Smad3 and fibronectin expressions were increased in male C57BL/6 mice underwent transverse aortic constriction (TAC) for 2weeks. Treatment with Candesartan (2mg/kg per day) could effectively downregulate Smad3 and fibronectin accompanied by upregulating of Smad7. Further data showed that Candesartan inhibited TGF-β1 signal-induced epithelial-to-mesenchymal transition (EMT) through attenuating matrix metalloproteinases (MMP-9), such effect was abolished by knocking-down Smad7. Moreover, TAC for 2weeks caused increased collagen deposition, thickness of left ventricular anterior and posterior wall at end-diastole (LVAWD and LVPWD) and LVEF% reduction, which were reversed by treatment with Candesartan, but failed after knocking-down Smad7. In addition, LV dP/dt(max) and dP/dt(min) were increased by TAC for 2weeks, and treatment with Candesartan or Nifedipine effectively depressed the high levels of dP/dt(min) induced by TAC. However, only Candesartan-mediated protective role in improving cardiac function was suppressed by tail-vein injection of Smad7 siRNA. This study uncovered a novel role for ARBs in preventing pressure overload-induced cardiac remodeling via Smad7 upregulation, which suppressed MMP-9 expression and TGF-β1 signal-mediated EMT progress.