Device-Detected Atrial Fibrillation Before and After Hospitalisation for Noncardiac Surgery or Medical Illness: Insights From ASSERT

Relationship between postoperative atrial fibrillation and its recurrence after lung resection

PURPOSE

Atrial fibrillation (AF) frequently occurs after pulmonary resection and is commonly referred to as postoperative atrial fibrillation (POAF). This study explored whether or not POAF is related to the recurrence of AF in the chronic phase.

METHODS

A total of 1311 consecutive patients without a history of AF who underwent lung resection based on a diagnosis of lung tumor were retrospectively analyzed.

RESULTS

POAF occurred in 46 patients (3.5%), and a logistic regression analysis revealed that the age (p < 0.05), history of hyperthyroidism (p < 0.05), and major lung resection (p < 0.05) were independent predictors of POAF. AF events in the chronic phase were observed in 15 (32.6%) and 45 (3.6%) patients with and without POAF, respectively. A Cox regression analysis revealed that POAF was the only independent predictor of AF development in the chronic phase (p < 0.01). The Kaplan-Meier curve and log-rank test revealed that the cumulative incidence of AF in the chronic phase was significantly higher in patients with POAF than in those without POAF (p < 0.01).

CONCLUSION

POAF was an independent predictor for AF in the chronic phase after lung resection. Further investigations including cases of catheter ablation and optimal medical therapy for patients with POAF after lung resection are needed.

Wireless Single-Lead ECG Monitoring to Detect New-Onset Postoperative Atrial Fibrillation in Patients After Major Noncardiac Surgery: A Prospective Observational Study

BACKGROUND

New-onset postoperative atrial fibrillation (POAF) is associated with several cardiovascular complications and higher mortality. Several pathophysiological processes such as hypoxia can trigger POAF, but these are sparsely elucidated, and POAF is often asymptomatic. In patients undergoing major gastrointestinal cancer surgery, we aimed to describe the frequency of POAF as automatically estimated and detected via wireless repeated sampling monitoring and secondarily to describe the association between preceding vital sign deviations and POAF.

METHOD

Patients ≥60 years of age undergoing major gastrointestinal cancer surgery were continuously monitored for up to 4 days postoperatively. Electrocardiograms were obtained every minute throughout the monitoring period. Clinical staff were blinded to all measurements. As for the primary outcome, POAF was defined as 30 consecutive minutes or more detected by a purpose-built computerized algorithm and validated by cardiologists. The primary exposure variable was any episode of peripheral oxygen saturation (Spo2) <85% for >5 consecutive minutes before POAF.

RESULTS

A total of 30,145 hours of monitoring was performed in 398 patients, with a median of 92 hours per patient (interquartile range [IQR], 54-96). POAF was detected in 26 patients (6.5%; 95% confidence interval [CI], 4.5-9.4) compared with 14 (3.5%; 95% CI, 1.94-5.83) discovered by clinical staff in the monitoring period. POAF was followed by 9.4 days hospitalization (IQR, 6.5-16) versus 6.5 days (IQR, 2.5-11) in patients without POAF. Preceding episodes of Spo2 <85% for >5 minutes (OR, 1.02; 95% CI, 0.24-4.00; P = .98) or other vital sign deviations were not significantly associated with POAF.

CONCLUSIONS

New-onset POAF occurred in 6.5% (95% CI, 4.5-9.4) of patients after major gastrointestinal cancer surgery, and 1 in 3 cases was not detected by the clinical staff (35%; 95% CI, 17-56). POAF was not preceded by vital sign deviations.

Meta-Analysis of New-Onset Atrial Fibrillation Versus No History of Atrial Fibrillation in Patients With Noncardiac Critical Care Illness

The incidence of new-onset secondary atrial fibrillation (NOSAF) is as high as 44% in noncardiac critical illness. A systematic review and meta-analysis were performed to evaluate the impact of NOSAF, compared with history of prior atrial fibrillation (AF) and no history of AF in noncardiac critically ill patients. Patients undergoing cardiothoracic surgery were excluded. NOSAF incidence, intensive care unit (ICU)/hospital length of stay (LOS), and mortality outcomes were analyzed. Of 2,360 studies reviewed, 19 studies met inclusion criteria (n = 306,805 patients). NOSAF compared with no history of AF was associated with increased in-hospital mortality (risk ratio [RR] 2.06, 95% confidence interval [CI] 1.76 to 2.41, p <0.001), longer ICU LOS (standardized difference in means [SMD] 0.66, 95% CI 0.41 to 0.91, p <0.001), longer hospital LOS (SMD 0.31, 95% CI 0.07 to 0.56, p = 0.001) and increased risk of long-term (>1 year) mortality (RR 1.76, 95% CI 1.29 to 2.40, p <0.001). NOSAF compared with previous AF was also associated with higher in-hospital mortality (RR 1.29, 95% CI 1.12 to 1.49, p <0.001), longer ICU LOS (SMD 0.37, 95% CI 0.03 to 0.70, p = 0.03) but no difference in-hospital LOS (SMD -0.18, 95% CI -0.66 to 0.31, p = 0.47). In conclusion, NOSAF, in the setting of noncardiac critical illness is associated with increased in-hospital mortality compared with no history of AF and previous AF. NOSAF (vs no history of AF) is also associated with increased long-term mortality.

Anticoagulation therapy in patients with post-operative atrial fibrillation: Systematic review with meta-analysis

BACKGROUND

Post-operative atrial fibrillation (POAF) is a relevant complication after surgery. Several studies have shown that POAF has important consequences for long-term morbidity and mortality, by increasing the risk of thromboembolic events. However, the use of oral anticoagulation (OAC) is not well established in this context.

METHODS

We searched MEDLINE, CENTRAL, PsycInfo and Web of Science for clinical trials and observational studies evaluating anticoagulation vs. no anticoagulation in patients with POAF (after cardiac or non-cardiac surgery). Data were screened and extracted by two independent reviewers. We performed a random- effects model to estimate the pooled odds ratio (OR) with 95% Confidence Intervals (CI), and heterogeneity was evaluated by I² statistics. The outcomes of interest were all-cause mortality, thromboembolic events, and bleeding events.

RESULTS

Overall, 10 observational retrospective studies were included: 5 studies with 203,946 cardiac surgery POAF patients, and 5 studies with 29,566 patients with POAF after non-cardiac surgery. In cardiac surgery POAF, the OAC use was associated with lower risk of thromboembolic events (OR 0.68; 95%CI 0.47-0.96, I² = 31%; 4 studies) and the bleeding risk was significantly increased (OR 4.30; 95%CI 3.69 to 5.02, 1 study). In non-cardiac surgery POAF, OAC did not significantly reduce the risk of thromboembolic events (OR 0.71, 95%CI 0.33-1.15; I² = 79%; 5 studies) but was associated with increased risk of bleeding (OR 1.20, 95%CI 1.10-1.32, I² = 0%; 3 studies). Mortality was not significantly reduced in both cardiac and non-cardiac surgery POAF.

CONCLUSION

Oral anticoagulation was associated with a lower risk of thromboembolic events in patients with POAF following cardiac surgery but not in non-cardiac surgery. Bleeding risk was increased in both settings. The confidence on pooled results is at most low, and further data, namely randomized controlled trials are necessary to derive robust conclusions.