The Association Among Blood Transfusions, White Blood Cell Count, and the Frequency of Post–Cardiothoracic Surgery Atrial Fibrillation: A Nested Cohort Study From the Atrial Fibrillation Suppression Trials I, II, and III

Risk Factors and Prognosis of Perioperative Atrial Fibrillation in Elderly Patients Undergoing VATS Lung Surgery: A Retrospective Cohort Study

Background

Atrial fibrillation (AF) has become the most common postoperative arrhythmia of thoracic surgery. This study aimed to investigate the risk factors and complications of perioperative atrial fibrillation (PoAF) in elderly patients who underwent video-assisted thoracoscopic surgery (VATS).

Methods

Data were collected from patients who underwent VATS between January 2013 and December 2022 at Peking Union Medical College Hospital (PUMCH). Univariable analyses and multivariable logistic regression analyses were used to determine the factors correlated with PoAF. Receiver operating characteristic (ROC) curve was used to evaluate the discrimination of the indicators to predict PoAF.

Results

The study enrolled 2920 patients, with a PoAF incidence of 5.2% (95% CI 4.4%-6.0%). In the logistic regression analyses, male sex (OR=1.496, 95% CI 1.056-2.129, P=0.024), left atrial anteroposterior dimension (LAD) ≥40 mm (OR=2.154, 95% CI 1.235-3.578, P=0.004), hypertension (HTN) without regular treatment (OR=2.044, 95% CI 0.961-3.921, P=0.044), a history of hyperthyroidism (OR=4.443, 95% CI 0.947-15.306, P=0.030), surgery of the left upper lobe (compared to other lung lobes) (OR=1.625, 95% CI 1.139-2.297, P=0.007), postoperative high blood glucose (BG) (OR=2.482, 95% CI 0.912-5.688, P=0.048), and the time of chest tube removal (per day postoperatively) (OR=1.116, 95% CI 1.038-1.195, P=0.002) were found to be significantly associated with PoAF. The area under the ROC curve was 0.707 (95% CI 0.519-0.799). 86.9% patients were successfully converted to sinus rhythm. Compared with the non-PoAF group, the PoAF group had significantly greater risks of prolonged air leakage, postoperative acute coronary syndrome, longer ICU stays, and longer hospital stays.

Conclusion

Male sex, LAD≥40 mm, HTN without regular treatment, a history of hyperthyroidism, surgery of the left upper lobe, postoperative BG, and the time of chest tube removal were associated with PoAF. These findings may help clinicians identify high-risk patients and take preventive measures to minimize the incidence and adverse prognosis of PoAF.

Modifiable factors associated with postoperative atrial fibrillation in older patients with hip fracture in an orthogeriatric care pathway: a nested case–control study

Background

Few data are available regarding post-operative atrial fibrillation (POAF) in non-cardiothoracic surgery, particularly orthopedic surgery. Hence, given the frequent incidence of POAF after surgery and its marked impact, we need to identify modifiable factors associated with POAF after hip fracture surgery in older patients.

Methods

We conducted a nested case–control study in the unit for perioperative geriatric care of an academic hospital in Paris from July 1, 2009 to December 31, 2019, enrolling all consecutive patients aged ≥ 70 years with hip fracture surgery and no history of permanent AF before admission (retrospective analysis of prospectively collected data). Patients with and without POAF were matched 1:5 on 5 baseline characteristics (age, hypertension, diabetes, coronary artery disease, cardiac failure).

Results

Of the 757 patients included, 384 were matched, and 64 had POAF. The incidence of POAF was 8.5%. The mean age was 86 ± 6 years, 298 (78%) patients were female, and the median Charlson Comorbidity Index was 6 (interquartile range 4–8). The median time from surgery to the occurrence of POAF was 2 days (1–4). On multivariable conditional logistic regression analysis (matched cohort), the modifiable factors present at admission associated with POAF were time to surgery > 48 h (odds ratio [OR] = 1.66, 95% confidence interval [1.01–2.81]) and > 2 units of packed red blood cells (OR = 3.94, [1.50–10.03]).

Conclusions

This study provides new information about POAF in older patients with hip fracture surgery, a surgical emergency whose complexity requires multidisciplinary care.

Non-invasive evaluation of new-onset atrial fibrillation after cardiac surgery: a protocol for the BigMap study

Aims

New‐onset atrial fibrillation (NOAF) is the most common complication after cardiac surgery, occurring in 25–50% of patients. It is associated with post‐operative stroke, increased mortality, prolonged hospital length of stay, and higher treatment costs. Previous small observational studies have identified the left atrium as a source of the electrical rotors and foci maintaining NOAF, but confirmation by a large prospective clinical study is still missing. The aim of the proposed study is to investigate whether the source of NOAF lies in the left atrium. The correct identification of NOAF‐maintaining structures in cardiac surgical patients might offer potential therapeutic targets for prophylactic perioperative ablation strategies.

Methods and results

This is a prospective single‐centre observational study of patients developing NOAF after cardiac surgery. The primary outcome is the description of NOAF‐maintaining structures within the atria. Key secondary outcomes include overall mortality, intensive care unit length of stay, hospital–ventilator‐free days, and proportion of persistent NOAF. In NOAF patients, the non‐invasive electrophysiological mapping will be conducted using a 252‐electrode electrocardiogram vest. After mapping, a low‐dose computed tomography scan of the chest will be performed to integrate the electrophysiological mapping results into a 3D picture of the heart. The study will include approximately 570 patients, of whom 30% (n = 170) are expected to develop NOAF. Sample size calculation revealed that 157 NOAF patients are necessary to assess the primary outcome. Patients will be tracked for a total of 5 years.

Conclusions

This is the largest prospective study to date describing the electrophysiological mechanisms of NOAF using non‐invasive mapping.

Coronary artery bypass grafting is associated with immunoparalysis of monocytes and dendritic cells

Coronary artery bypass grafting (CABG) triggers a systemic inflammatory response that may contribute to adverse outcomes. Dendritic cells (DC) and monocytes are immunoregulatory cells potentially affected by CABG, contributing to an altered immune state. This study investigated changes in DC and monocyte responses in CABG patients at 5 time-points: admission, peri-operative, ICU, day 3 and day 5. Whole blood from 49 CABG patients was used in an ex vivo whole blood culture model to prospectively assess DC and monocyte responses. Lipopolysaccharide (LPS) was added in parallel to model responses to an infectious complication. Co-stimulatory and adhesion molecule expression and intracellular mediator production was measured by flow cytometry. CABG modulated monocyte and DC responses. In addition, DC and monocytes were immunoparalysed, evidenced by failure of co-stimulatory and adhesion molecules (eg HLA-DR), and intracellular mediators (eg IL-6) to respond to LPS stimulation. DC and monocyte modulation was associated with prolonged ICU length of stay and post-operative atrial fibrillation. DC and monocyte cytokine production did not recover by day 5 post-surgery. This study provides evidence that CABG modulates DC and monocyte responses. Using an ex vivo model to assess immune competency of CABG patients may help identify biomarkers to predict adverse outcomes.

Predictors of Postoperative Atrial Fibrillation after Beating-Heart Coronary Artery Bypass Surgery: Is Cardiopulmonary Bypass a Risk Factor?

Background

To determine the risk factors and postoperative outcomes of new-onset atrial fibrillation (AF) following beating-heart coronary artery bypass grafting (CABG) surgery.

Methods

A total of 458 patients who underwent beating-heart CABG without the use of aortic cross clamping and cardioplegic arrest between January 2011 and January 2015 were included in the study, and they were divided into two groups according to the development of new-onset AF as the AF group (n = 143) and non-AF group (n = 315). Both groups were compared in terms of preoperative clinical features and perioperative data, and the risk factors and postoperative outcomes of AF following beating-heart CABG were determined.

Results

The incidence of postoperative AF was 31.2%. Patients in the AF group were significantly older (68.08 ± 7.76 vs. 61.76 ± 9.83 years, p ≤ 0.001) and had significantly higher use of cardiopulmonary bypass during surgery (69.2% vs. 43.2%, p ≤ 0.001) than the patients in the non-AF group. The patients with AF also had statistically significantly longer lengths of intensive care unit and hospital stay than those without AF (43.79 ± 32.39 vs. 30.49 ± 33.31 hours, p ≤ 0.001, and 8.20 ± 4.37 vs. 5.77 ± 2.16 days, p ≤ 0.001, respectively).

Conclusions

Our study revealed that age and the use of cardiopulmonary bypass during surgery were independent predictors of AF following beating-heart CABG. In addition, postoperative AF was associated with prolonged intensive care unit and hospital stay. Further prospective randomized studies with larger patient series are required to support our research and attain more accurate data.

Storage time of intraoperative transfused allogeneic red blood cells is not associated with new-onset postoperative atrial fibrillation in cardiac surgery

BACKGROUND

Allogeneic red blood cell (RBC) transfusion has been associated with new-onset postoperative atrial fibrillation (POAF) following cardiac surgery. Prolonged storage time of RBC may increase the risk. The primary aim of the study was to evaluate whether the storage time of RBC is associated with development of POAF.

MATERIALS AND METHODS

Pre-, per- and postoperative data were retrieved from the Western Denmark Heart Registry and local blood banks regarding patients who underwent coronary artery bypass surgery, valve surgery or combined procedures in Aalborg or Aarhus University Hospital during 2010-2014. Multiple logistic regression was used to determine the risk of POAF according to transfusion of RBC on the day of surgery. Furthermore, we determined trend in storage time of RBC according to risk of POAF using restricted cubic splines. Patients with a history of preoperative atrial fibrillation, patients who received transfusions preoperative and patients who died at the day of surgery were among excluded patients.

RESULTS

A total of 2,978 patients with a mean age of 66.4 years were included and 609 patients (21%) received RBC transfusion on the day of surgery. POAF developed in 752 patients (25%) and transfused patients were at an increased risk compared with non-transfused patients (adjusted Odds Ratios for patients receiving RBC: 1.37; 95% CI: 1.11-1.69, P-value = 0.004). However, RBC transfusion was not necessarily the cause of POAF and may only be a marker for development of POAF. There was no significant association between storage time of RBC and POAF.

CONCLUSIONS

In contrast to intraoperative allogeneic RBC transfusion in general, increased storage time of RBC is not associated with development of POAF in cardiac surgery.

Potentially modifiable risk factors for atrial fibrillation following lung resection surgery: a retrospective cohort study

Atrial fibrillation is the most frequent arrhythmia after thoracic surgery and is associated with increased hospital costs, morbidity and mortality. In this study, we aimed to identify potentially modifiable risk factors for postoperative atrial fibrillation following lung resection surgery and to suggest possible measures to reduce risk. We retrospectively reviewed the medical records of 4731 patients who underwent lobectomy or more major lung resection over a 6-year period. Patients who developed atrial fibrillation postoperatively and required treatment were included in the postoperative atrial fibrillation group, while the remaining patients were assigned to the non-postoperative atrial fibrillation group. Risk factors for postoperative atrial fibrillation were analysed by multivariate analysis and propensity score matching. Overall, 12% of patients developed postoperative atrial fibrillation. Potentially modifiable risk factors for postoperative atrial fibrillation were excessive alcohol consumption (odds ratio (OR) = 1.48, 95% CI 1.08-2.02, p = 0.0140), red cell transfusion (2.70(2.13-3.43), p < 0.0001), use of inotropes (1.81(1.42-2.31), p < 0.0001) and open (vs. thoracoscopic) surgery (1.59(1.23-2.05), p < 0.0001). Compared with inotrope use, vasopressor administration was not related to postoperative atrial fibrillation. Use of steroids or thoracic epidural anaesthesia did not reduce the incidence of postoperative atrial fibrillation. We conclude that high alcohol consumption, red cell transfusion, use of inotropes and open surgery are potentially modifiable risk factors for postoperative atrial fibrillation. Pre-operative alcohol consumption needs to be addressed. Avoiding red cell transfusion and performing lung resection via video-assisted thoracoscopic surgery may reduce the incidence of postoperative atrial fibrillation and the administration of vasopressors rather than inotropes is preferred.

Association of White Blood Cell Count and Differential with the Incidence of Atrial Fibrillation: The Atherosclerosis Risk in Communities (ARIC) Study

Background

Although inflammation is involved in the development of atrial fibrillation (AF), the association of white blood cell (WBC) count and differential with AF has not been thoroughly examined in large cohorts with extended follow-up.

Methods

We studied 14,500 men and women (25% blacks, 55% women, mean age 54) free of AF at baseline (1987–89) from the Atherosclerosis Risk in Communities (ARIC) study, a community-based cohort in the United States. Incident AF cases through 2010 were identified from study electrocardiograms, hospital discharge records and death certificates. Multivariable Cox proportional hazards regression was used to estimate hazard ratios (HR) and 95% confidence intervals (CI) for AF associated with WBC count and differential.

Results

Over a median follow-up time of 21.5 years for the entire cohort, 1928 participants had incident AF. Higher total WBC count was associated with higher AF risk independent of AF risk factors and potential confounders (HR 1.09, 95% CI 1.04–1.15 per 1-standard deviation [SD] increase). Higher neutrophil and monocyte counts were positively associated with AF risk, while an inverse association was identified between lymphocyte count and AF (multivariable adjusted HRs 1.16, 95% CI 1.09–1.23; 1.05, 95% CI 1.00–1.11; 0.91, 95% CI 0.86–0.97 per 1-SD, respectively). No significant association was identified between eosinophils or basophils and AF.

Conclusions

High total WBC, neutrophil, and monocyte counts were each associated with higher AF risk while lymphocyte count was inversely associated with AF risk. Systemic inflammation may underlie this association and requires further investigation for strategies to prevent AF.

Postoperative atrial fibrillation in patients undergoing non-cardiac non-thoracic surgery: A practical approach for the hospitalist

New postoperative atrial fibrillation (POAF) is the most common perioperative arrhythmia and its reported incidence ranges from 0.4 to 26% in patients undergoing non-cardiac non-thoracic surgery. The incidence varies according to patient characteristics such as age, presence of structural heart disease and other co-morbidities, as well as the type of surgery performed. POAF occurs as a consequence of adrenergic stimulation, systemic inflammation, or autonomic activation in the intra or postoperative period (e.g. due to pain, hypotension, infection) in the setting of a susceptible myocardium and other predisposing factors (e.g. electrolyte abnormalities). POAF develops between day 1 and day 4 post-surgery and it is often considered a self-limited entity. Its acute management involves many of the same strategies used in non-surgical patients but the optimal long-term management is challenging because of the limited available evidence. Several studies have shown an association between occurrence of POAF and in-hospital morbidity, mortality, and length of stay. Although, traditionally, POAF was considered to have a generally favorable long-term prognosis, recent data have shown an association with an increased risk of stroke at 1 year after hospitalization. It is unknown, however, whether strategies to prevent POAF or for rate/rhythm control when it does occur, lead to a reduction in morbidity or mortality. This suggests the need for future studies to better understand the risks associated with POAF and to determine optimal strategies to minimize long-term thromboembolic risks. In this article, we summarize the current knowledge on epidemiology, pathophysiology, and short- and long-term management of POAF after non-cardiac non-thoracic surgery with the goal of providing a practical approach to managing these patients for the non-cardiologist clinician.

Comparison of results of autologous versus homologous blood transfusion in open-heart surgery

Background

The aim of this study was to determine a method to decrease the use of homologous blood during openheart surgery using a simple blood-conservation protocol. We removed autologous blood from the patient before bypass and used isovolumetric substitution. We present the results of this protocol on morbidity and mortality of surgery patients from two distinct time periods.

Methods

Patients from the two surgical phases were enrolled in this retrospective study in order to compare the outcomes using autologous or homologous blood in open-heart surgery. A total of 323 patients were included in the study. The autologous transfusion group (group 1) comprised 163 patients and the homologous transfusion group (group 2) 160 patients. In group 1, autologous bloods were prepared via a central venous catheter that was inserted into the right internal jugular vein in all patients, using the isovolumetric replacement technique. The primary outcome was postoperative in-hospital mortality and mortality at 30 days. Secondary outcomes included the length of stay in hospital and in intensive care unit (ICU), time for extubation, re-intubations, pulmonary infections, pneumothorax, pleural effusions, atrial fibrillation, other arrhythmias, renal disease, allergic reactions, mediastinitis and sternal dehiscence, need for inotropic support, and low cardiac-output syndrome (LCOS).

Results

The mean ages of patients in groups 1 and 2 were 64.2 ± 10.3 and 61.5 ± 11.6 years, respectively. Thirty-eight of the patients in group 1 and 30 in group 2 were female. There was no in-hospital or 30-day mortality in either group. The mean extubation time, and ICU and hospital stays were significantly shorter in group 1. Furthermore, postoperative drainage amounts were less in group 1. There were significantly fewer patients with postoperative pulmonary complications, pneumonia, atrial fibrillation and renal disease. The number of patients who needed postoperative inotropic support and those with low cardiac output was also significantly less in group 1.

Conclusion

Autologous blood transfusion is a safe and effective method in carefully selected patients undergoing cardiac surgery. It not only prevents transfusion-related co-morbidities and complications but also enables early extubation time and shorter ICU and hospital stay. Furthermore, it reduces the cost of surgery.

Off-pump surgery: is it beneficial in patients with left ventricular dysfunction?

On-pump coronary artery bypass surgery remains the gold standard for complex multivessel disease. Off-pump revascularization has matured as a technique over the last twenty years, but is used in less than 20% of cases worldwide. The poor uptake has been attributed to the significant learning curve in learning the procedure and conflicting evidence reports, together with concerns over mortality related conversion, graft patency and completeness of revascularization. Given these concerns, patient selection continues to be paramount and the subgroups that benefit most are hotly debated. Patients with left ventricular dysfunction constitute a high-risk subgroup which is enlarging in size. There is some evidence to suggest that avoidance of cardiopulmonary bypass in this group may lead to superior results in terms of early mortality, non-cardiac complications and organ dysfunction. Even with the theoretical risk of incomplete revascularization, the technique may be an attractive option in managing high-risk patients.

Blood transfusions in cardiac surgery: indications, risks, and conservation strategies

Although red blood cell (RBC) transfusions are frequently used in cardiac operations, an increasing amount of data has demonstrated deleterious consequences. Consequently, the appropriate use of this limited resource is unclear. In this review, we discuss the relationship between anemia and the outcomes of cardiac surgical procedures, the risks associated with RBC transfusion, and the impact of blood transfusions on mortality and morbidity after cardiac operations. The review concludes with a discussion of randomized trials comparing restrictive versus liberal transfusion strategies and a consideration of blood conservation techniques.

White blood cell count and risk of incident atrial fibrillation (from the Framingham Heart Study)

Several studies have reported that inflammatory markers are associated with atrial fibrillation (AF). The white blood cell (WBC) count is a widely available and broadly used marker of systemic inflammation. We sought to investigate the association between an increased WBC count and incident AF and whether this association is mediated by smoking, myocardial infarction, and heart failure. We examined the participants in the Framingham Heart Study original cohort. Cox proportional hazard regression analysis was used to examine the relation between the WBC count and incident AF during a 5-year follow-up period. We adjusted for standard AF risk factors, smoking, previous myocardial infarction, and interim myocardial infarction and heart failure before the incident AF. Our sample consisted of 936 participants (mean age 76 ± 6 years and 61% women). The median WBC count was 6.4 × 10(9)/L (25th to 75th percentile 5.6 × 10(9)/L to 7.8 × 10(9)/L). During a median 5-year follow-up period, 82 participants (9%) developed new-onset AF. After adjusting for standard risk factors for AF, an increased WBC count was significantly associated with incident AF, with a hazard ratio per SD (0.26 × 10(9)/L) increase of 2.22 (95% confidence interval 1.10 to 4.48; p = 0.03). We found no substantive differences adjusting for smoking, previous myocardial infarction, interim myocardial infarction, or heart failure. In conclusion, in our community-based sample, an increased WBC count was associated with incident AF during 5 years of follow-up. Our findings provide additional evidence for the relation between systemic inflammation and AF.

Predictors and impact of postoperative atrial fibrillation on patients' outcomes: a report from the Randomized On Versus Off Bypass trial

OBJECTIVE

The study objective was to determine the predictors of postoperative atrial fibrillation (POAF) in patients randomized to conventional coronary artery bypass graft (on-pump coronary artery bypass [ONCAB]) versus beating heart coronary surgery (off-pump coronary artery bypass [OPCAB]).

METHODS

The subgroup of 2103 patients (of 2203 enrollees) in the Randomized On Versus Off Bypass trial with no POAF was studied (1056 patients in the ONCAB group and 1047 patients in the OPCAB group). Univariate and multivariate analyses were used to identify the predictors of POAF and the impact of POAF on outcomes.

RESULTS

Use of ONCAB versus OPCAB was not associated with increased rates of POAF. Older age (P < .0001), white race (P < .001), and hypertension (P < .002) were predictors of POAF on multivariate analysis. In general, POAF led to a higher rates of reintubation (ONCAB: 6.3% vs 0.8% no POAF, P < .001; OPCAB: 7.4% vs 1.8% no POAF, P < .0001) and prolonged ventilatory support (ONCAB: 7.1% vs 2.3% no POAF, P = .001; OPCAB: 9.2% vs 3.4% no POAF, P = .0003). The rate of any early adverse outcome was higher in patients with POAF (all patients: 10% POAF vs 4.7% no POAF, P < .0001; ONCAB: 9% POAF vs 4.3% no POAF, P = .008; OPCAB: 11% POAF vs 5.1% no POAF, P = .001). The 1-year all cause mortality was higher with POAF for both groups (ONCAB: 5.4% POAF vs 2% no POAF, P = .009; OPCAB: 5.1% POAF vs 2.6% no POAF, P = .07). POAF was independently associated with early composite end point (odds ratio [OR], 2.23; confidence interval [CI], 1.55-3.22; P < .0001), need for new mechanical support (OR, 3.25; CI, 1.39-7.61; P = .007), prolonged ventilatory support (OR, 2.93; CI, 1.89-4.55; P < .0001), renal failure (OR, 5.42; CI, 1.94-15.15; P = .001), and mortality at 12 months (OR, 1.94; CI, 1.14-3.28; P = .01).

CONCLUSIONS

In the Randomized On Versus Off Bypass trial, the strategy of revascularization did not affect the rate of POAF. Age, race, and hypertension were predictors of POAF. POAF was independently associated with a higher short-term morbidity and higher 1-year mortality rates.

Postoperative atrial fibrillation

Postoperative atrial fibrillation (POAF) is common among surgical patients and associated with a worse outcome. Pathophysiology of POAF is not fully disclosed, and several perioperative factors could be involved. Direct cardiac stimulation from perioperative use of catecholamines or increased sympathetic outflow from volume loss/anaemia/pain may play a role. Metabolic alterations, such as hypo-/hyperglycaemia and electrolyte disturbances, may also contribute to POAF. Moreover, inflammation, both systemic and local, may play a role in its pathogenesis. Strategies to prevent POAF aim at reducing its incidence and ameliorate global outcome of surgical patients. Nonpharmacological prophylaxis includes an adequate control of postoperative pain, the use of thoracic epidural analgesia, optimization of perioperative oxygen delivery, and, possibly, modulation of surgery-associated inflammatory response with immunonutrition and antioxidants. Perioperative potassium and magnesium depletion should be corrected. The impact of those interventions on patients outcome needs to be further investigated.

Predictors of atrial fibrillation occurrence after coronary artery bypass graft surgery

PURPOSE

Postoperative atrial fibrillation (AF) is the most common complication after coronary artery bypass graft (CABG) surgery, with an incidence of 20%-50%. The objective of this study was to investigate perioperative risk factors of postoperative sustained AF by the way of logistic regression analysis.

METHODS

Data for the last 98 patients who had undergone CABG surgery before January 2010 were retrospectively collected and analyzed.

RESULTS

Postoperative sustained AF was detected in 34 (34.7%) patients. Mean arterial blood pressure, previous hypertension (HT), previous AF, previous chronic obstructive pulmonary disease, aortic cross-clamp time, cardiopulmonary bypass time, postoperative urea, postoperative creatinine, postoperative potassium, extubation time, chest tube drainage, units of transfused packed red blood cells (pRBC), and postoperative pneumonia were associated with higher occurrence of postoperative sustained AF according to the univariate analysis. Upon logistic regression analysis, pRBC transfusion, previous AF, and preoperative HT remained independent predictors for the development of postoperative sustained AF.

CONCLUSION

On-pump versus off-pump CABG is not significantly associated with AF development so long as the operating time does not extend over a certain time period. pRBC transfusion was the single risk factor that is amenable to intervention at the time of operation. Unneeded transfusion of pRBCs must be prohibited. Also, serious precautions must be taken against postoperative pneumonia to avoid postoperative AF occurrence.

Risk of cardiac arrhythmias and conduction abnormalities in patients with acute myocardial infarction receiving packed red blood cell transfusions

PURPOSE

Although transfusion has been linked to the development of atrial fibrillation (AF) in cardiac surgical patients, this association has not been investigated in patients with acute myocardial infarction (AMI). Evidence supports an inflammatory mechanism in the development of AF, and red cell transfusions also elicit an inflammatory response. We therefore sought to evaluate whether packed red blood cell transfusion increases the risk of AF, ventricular tachycardia (VT), and other arrhythmias and conduction abnormalities in patients with AMI.

MATERIALS AND METHODS

This is a retrospective study on patients with AMI and no prior history of AF, admitted to a critical care area and entered in Project Impact database from 08/2003-12/2007. Primary outcome measures were new-onset cardiac arrhythmias or conduction disturbances.

RESULTS

Transfused patients had significantly higher incidences of AF (4.7% vs 1.3%, P = .008), cardiac arrest (9.5% vs 1.7%, P < .001) and heart block (3.4% vs 0.1%, P < .001), and a trend toward a higher incidence of VT (3.4% vs 1.3%, P = .058). Multivariate regression analysis confirmed transfusion as an independent risk factor for "non-lethal" cardiac events (AF/heart block; odds ratio [OR], 4.7 [1.9-11.9]; P = .001), "lethal" events (VT/cardiac arrest; OR, 2.4 [1.1-5]; P = .016), and all cardiac events (OR, 2.8 [1.5-65.1]; P = .001). Transfused patients had significantly longer length of stay (P < .0001) and significantly higher mortality rates than nontransfused patients (OR, 3 [1.7-5.5]; P < .001).

CONCLUSIONS

Packed red blood cell transfusion is independently associated with an increased risk of new-onset cardiac arrhythmias and conduction abnormalities in the setting of AMI, even after controlling for traditional risk factors.