Atrial Fibrillation After Aortic Arch Repair Requiring Deep Hypothermic Circulatory Arrest: Incidence, Clinical Outcome, and Clinical Predictors

Atrial Fibrillation after Descending Aorta Repair: Occurrence, Risk Factors, and Impact on Outcomes

BACKGROUND

 As risks of repairing the descending thoracic and thoracoabdominal aorta diminish, common complications that may prolong hospital stay, or actually increase risk, require attention. One such complication is postoperative atrial fibrillation (AF). Therefore, we characterized prevalence of, risk factors for, and effects of postoperative atrial fibrillation (PoAF) after descending and thoracoabdominal aorta repair.

METHODS

 From January 2000 to January 2011, 696 patients underwent open descending or thoracoabdominal aorta repair at Cleveland Clinic. Operations approached via median sternotomy (n = 178) and patients treated preoperatively for arrhythmias (32 amiodarone, 9 paced) or in AF on preoperative electrocardiogram (n = 14) were excluded, leaving 463. Logistic regression analysis identified risk factors for PoAF. Temporal relation of PoAF with postoperative morbidities was determined, and outcomes following PoAF were compared between propensity-matched pairs.

RESULTS

 New-onset PoAF occurred in 101 patients (22%) at a median 68 hours of postincision. Risk factors included older age (p = 0.002) and history of remote AF (p = 0.0004) but not operative details, such as pericardiotomy for cardiac cannulation. Hypoperfusion and neurologic complications tended to precede PoAF, whereas sepsis, respiratory failure, and dialysis followed. Among 94 propensity-matched patient pairs, those developing PoAF were more likely to experience hypoperfusion (p = 0.006), respiratory failure (p = 0.009), dialysis (p = 0.04), paralysis (p < 0.0001), longer intensive care unit stay (median 7 vs. 5 d, p = 0.02), and longer postoperative hospital stay (median 15 vs. 13 d, p = 0.004). However, hospital death was similar (6/94 PoAF [6.4%] vs. 7/94 no PoAF [7.4%], p = 0.8).

CONCLUSION

 PoAF after descending thoracic aorta surgery is relatively common and a part of a constellation of other serious complications prolonging postoperative recovery. While PoAF was associated with adverse events, it did not impact postoperative cost and mortality. Descending thoracic aorta surgery is by itself comorbid enough, which is likely why PoAF does not have a more significant effect on postoperative recovery and cost.

New-Onset Postoperative Atrial Fibrillation After Total Arch Repair Is Associated With Increased In-Hospital Mortality

Background

It is well established that postoperative atrial fibrillation (POAF) is associated with adverse postoperative outcomes after major cardiac operations. The purpose of this study was to investigate the incidence of new‐onset POAF after successful total arch repair surgery and the association between POAF and in‐hospital mortality.

Methods and Results

All consecutive patients undergoing total arch repair from September 2012 to December 2019 in Fuwai hospital were enrolled (n=1280). Patients diagnosed with preoperative atrial fibrillation were excluded. POAF was diagnosed as the new‐onset atrial fibrillation or flutter for more than 5 minutes based on continuous electrocardiogram monitoring. A logistic regression model was used to determine predictors of in‐hospital mortality. Multivariable adjustment, inverse probability of treatment weighting, and propensity score matching were used to adjust for confounders. POAF was diagnosed in 32.3% (411/1271) of this cohort population. The occurrence of new‐onset POAF was associated with age (odds ratio [OR], 1.05; 95% CI, 1.04–1.06; P<0.001), male sex (OR, 0.72; 95% CI, 0.52–0.98; P=0.035), and surgery duration (OR, 1.2; 95% CI, 1.12–1.28; P<0.001). The in‐hospital mortality was significantly higher in patients with POAF than those without POAF (10.7% versus 2.4%, P<0.001). Inverse probability of treatment weighting and propensity score matching analyses confirmed the results. The increased in‐hospital mortality in POAF group still existed among subgroup analysis based on different age, sex, hypertension, smoking, and hypokalemia, combined with cardiac surgery, and deep hypothermic circulatory arrest.

Conclusions

More careful attention should be given to POAF after total arch repair surgery. The incidence of POAF after total arch repair surgery was 32.3% and associated with increased in‐hospital mortality. The elderly female patient who experienced longer operation duration was at highest risk for POAF.

Optimising risk factors for atrial fibrillation post-cardiac surgery

Postoperative atrial fibrillation (POAF) is an ongoing complication following cardiac surgery, with an incidence of 15%-60%. It is associated with substantial mortality and morbidity, as well increased hospital stays and healthcare costs. The pathogenesis is not fully understood, but the literature suggests that POAF occurs when transient, postoperative triggers act on vulnerable atrial tissue produced by preoperative, procedure-induced and postoperative processes such as inflammation, oxidative stress, autonomic dysfunction and electrophysiological remodelling of the atrial tissues. This sets the stage for arrhythmogenic mechanisms, such as ectopic firing secondary to triggered activity and re-entry mechanisms generating POAF. Preoperative factors include advanced age, sex, ethnicity, cardiovascular risk factors, preoperative drugs, electrocardiogram and echocardiogram abnormalities. Procedural factors include: the use of cardiopulmonary bypass and aortic cross clamp, type of cardiac surgery, use of hypothermia, left ventricular venting, bicaval cannulation and exclusion of the left atrial appendage. Postoperative factors include postoperative drugs, electrolyte and fluid balance and infection. This review explores the pathogenesis of POAF and the contribution of these perioperative factors in the development of POAF. Patients can be risk stratified for targeted treatment and prophylaxis, and how these factors can be attenuated to improve POAF outcomes following cardiac surgery.

Elective hypothermic circulatory arrest to address aortic pathology is safe for the elderly

BACKGROUND

Due to assumptions of excessive risk, hypothermic circulatory arrest (HCA) has been considered prohibitive in elderly patients. However, as more elderly patients are referred for assessment of difficult aortic valve, ascending aorta, and aortic arch pathology, the risk of HCA in these patients needs to be addressed. We hypothesized that the use of HCA would not increase mortality or complications in elderly patients compared to younger counterparts.

METHODS

We retrospectively reviewed the charts of adult patients who underwent elective HCA between January 1995 and June 2007. Of 147 procedures, 45 patients were >or=75 years old. These patients were compared to their younger counterparts in terms of comorbidities, operations, and complications.

RESULTS

Comparing patients >or=75 years old to their younger counterparts revealed no significant differences in outcomes including nearly identical rates of confusion (>or=75 15% vs <75 9%, p > 0.5) and stroke (>or=75 11% vs <75 7%, p > 0.2). There was also no difference in 30-day mortality (>or=75 7% vs <75 7%, p = 0.9). Lengths of hospital stays and intensive care unit stays were longer in the older patients, but this was not statistically significant.

CONCLUSION

In this study, elderly patients faired well with HCA compared to younger patients. These data suggest that the use of HCA is safe in selected elderly patients. Elderly patients should be considered for indicated procedures of the aortic valve, ascending aorta, and aortic arch regardless of age.

Prevention of atrial fibrillation following cardiac surgery: basis for a novel therapeutic strategy based on non-hypoxic myocardial preconditioning

Atrial fibrillation is the most common complication of cardiac surgical procedures performed with cardiopulmonary bypass. It contributes to increased hospital length of stay and treatment costs. At present, preventive strategies offer only suboptimal benefits, despite improvements in anesthesia, surgical technique, and medical therapy. The pathogenesis of postoperative atrial fibrillation is considered to be multifactorial. However oxidative stress is a major contributory factor representing the unavoidable consequences of ischemia/reperfusion cycle occurring in this setting. Considerable evidence suggests the involvement of reactive oxygen species (ROS) in the pathogenic mechanism of this arrhythmia. Interestingly, the deleterious consequences of high ROS exposure, such as inflammation, cell death (apoptosis/necrosis) or fibrosis, may be abrogated by a myocardial preconditioning process caused by previous exposure to moderate ROS concentration known to trigger survival response mechanisms. The latter condition may be created by n-3 PUFA supplementation that could give rise to an adaptive response characterized by increased expression of myocardial antioxidant enzymes and/or anti-apoptotic pathways. In addition, a further reinforcement of myocardial antioxidant defenses could be obtained through vitamins C and E supplementation, an intervention also known to diminish enzymatic ROS production. Based on this paradigm, this review presents clinical and experimental evidence supporting the pathophysiological and molecular basis for a novel therapeutic approach aimed to diminish the incidence of postoperative atrial fibrillation through a non-hypoxic preconditioning plus a reinforcement of the antioxidant defense system in the myocardial tissue.