To Örebro University

Atrial fibrillation (AF) is associated with an increased risk of stroke, heart failure, and cardiovascular death. Ablation therapy can reduce AF symptoms, arrhythmia burden and mortality, and is performed endovascularly or surgically. Coronary revascularization involve surgical or endovascular techniques. New-onset AF is more commonly reported following surgery, but systematic heart rhythm monitoring strategies are rare. This thesis aimed to investigate the short- and long-term outcomes of totally endoscopic surgical ablation, as well as the short- and long-term incidence, risk factors, and burden of AF after cardiac revascularization.

Study I was a randomized controlled trial comparing totally endoscopic epicardial box lesion ablation of the left atrium to medical therapy in patients with long-standing persistent AF (LSPAF). At 1 year, 80% of ablated patients were in sinus rhythm (SR) without the need for antiarrhythmic drugs. Ablation improved physical working capacity, left ventricular systolic function, and self-reported quality of life.

Studies II, III, and IV were prospective cohort studies conducted in a real-world population of patients undergoing coronary artery bypass graft (CABG) or per-cutaneous coronary intervention (PCI). A systematic in-hospital and outpatient arrhythmia detection strategy was employed to determine the short-term (30-day) and long-term (24-month) cumulative incidence of new-onset AF. New-onset AF was common after CABG, with most events occurring within the first 30 days, whereas it was rare after PCI, with an even distribution over the 24 months. Undergoing CABG was a significant risk factor for developing new-onset AF. For patients who underwent CABG and developed postoperative AF, the arrhythmia burden was low during the first postoperative year.

Study V was a retrospective cohort study investigating the long-term rhythm out-come of the patients from Study I. At a mean follow-up of 9 years, most patients were in AF. The mean time for freedom from AF after totally endoscopic box lesion ablation for LSPAF was 23 months.

Objectives: Atrial fibrillation is a common arrhythmia in patients with ischemic heart disease. This study aimed to determine the cumulative incidence of new-onset atrial fibrillation after percutaneous coronary intervention or coronary artery bypass grafting surgery during 30 days of follow-up.

Design: This was a prospective multi-center cohort study on atrial fibrillation incidence following percutaneous coronary intervention or coronary artery bypass grafting for stable angina or non-ST-elevation acute coronary syndrome. Heart rhythm was monitored for 30 days postoperatively by in-hospital telemetry and handheld thumb ECG recordings after discharge were performed. The primary endpoint was the cumulative incidence of atrial fibrillation 30 days after the index procedure.

Results: In-hospital atrial fibrillation occurred in 60/123 (49%) coronary artery bypass graft and 0/123 percutaneous coronary intervention patients (p < .001). The cumulative incidence of atrial fibrillation after 30 days was 56% (69/123) of patients undergoing coronary artery bypass grafting and 2% (3/123) of patients undergoing percutaneous coronary intervention (p < .001). CABG was a strong predictor for atrial fibrillation compared to PCI (OR 80.2, 95% CI 18.1-354.9, p < .001). Thromboembolic stroke occurred in-hospital in one coronary artery bypass graft patient unrelated to atrial fibrillation, and at 30 days in two additional patients, one in each group. There was no mortality.

Conclusion: New-onset atrial fibrillation during 30 days of follow-up was rare after percutaneous coronary intervention but common after coronary artery bypass grafting. A prolonged uninterrupted heart rhythm monitoring strategy identified additional patients in both groups with new-onset atrial fibrillation after discharge.

Diagnostic mediastinoscopy is a procedure with well-known serious complications: Hemorrhage, mediastinitis, pneumothorax and recurrent nerve damage. Esophageal perforation is a less known potentially life-threatening complication. Here the case of a young man with an iatrogenic esophageal perforation following a diagnostic mediastinoscopy is presented with a literary review of previously published cases.

BACKGROUND: Atrial fibrillation (AF) is a rapidly increasing global public health concern entailing a high risk for ischemic stroke that can largely be avoided with anticoagulation therapy. AF is often underdiagnosed and there is a need for a reliable method of detection in individuals with additional risk factors for stroke such as coronary artery disease. We aimed to validate an automatic rhythm interpretation algorithm in thumb ECG in subjects with recent coronary revascularization.

METHODS: Thumb ECG, a patient-operated handheld single-lead ECG recording device with an automatic interpretation algorithm, was performed three times daily for a month after coronary revascularization and 2-week periods 3, 12, and 24 months post-procedure. The detection of AF by the automatic algorithm on subject and single-strip ECG level was compared to manual interpretation.

RESULTS: 48,308 of 30 s thumb ECG recordings from 255 subjects (mean 212 ± 3.5 recordings per subject) were retrieved from a database (AF 47 subjects/655 recordings; non-AF 208 subjects/47,653 recordings). The algorithm sensitivity at subject level was 100%, specificity 11.2%, positive predictive value (PPV) 20.2%, and negative predictive value (NPV) 100%. At the single-strip ECG level, sensitivity was 87.6%, specificity 94.0%, PPV 16.8%, and NPV 99.8%. The most common reasons for false positive results were technical disturbance and frequent ectopic beats.

CONCLUSIONS: The automatic interpretation algorithm in a handheld thumb ECG device can rule out AF in patients recently undergoing coronary revascularization with high accuracy, but manual confirmation is needed to confirm the diagnose of AF because of high false positive rates.

OBJECTIVES: Acute type A aortic dissection (ATAAD) is a rare but severe condition, routinely treated with emergent cardiac surgery. Many surgeons have the notion that patients with ATAAD tend to come in clusters, but no studies have examined these observations. This investigation was undertaken to study the potential association between the lunar cycle and the incidence of ATAAD.

METHODS: We collected information on 2995 patients who underwent ATAAD surgery at centres from the Nordic Consortium for Acute Type A Aortic Dissection collaboration. We cross-referenced the time of surgery with lunar phase using a case-crossover design with 2 different definitions of full moon (>99% illumination and the 7-day full moon period).

RESULTS: The period when the moon was illuminated the most (99% definition) did not show any significant increase in incidence for ATAAD surgery. However, when the full moon period was compared with all other moon phases, it yielded a relative risk of 1.08 [95% confidence interval (CI) 1.00-1.17, P = 0.057] and, compared to waxing moon, only the relative risk was 1.11 (95% CI 1.01-1.23, P = 0.027). The peak incidence came 4-6 days after the moon was fully illuminated.

CONCLUSIONS: This study found an overrepresentation of surgery for ATAAD during the full moon phase. The explanation for this is not known, but we speculate that sleep deprivation during full moon leads to a temporary increase in blood pressure, which in turn could trigger rupture of the aortic wall. While this finding is interesting, it needs to be corroborated and the clinical implications are debateable.

BACKGROUND: The outcome in patients after surgery for acute type A aortic dissection without replacement of the part of the aorta containing the primary tear is undefined.

METHODS: Data of 1122 patients who underwent surgery for acute type A aortic dissection in 8 Nordic centers from January 2005 to December 2014 were retrospectively analyzed. The patients with primary tear location unfound, un-known, not confirmed, or not recorded (n = 243, 21.7%) were excluded from the analysis. The patients were divided into 2 groups according to whether the aortic reconstruction encompassed the portion of the primary tear (tear resected [TR] group, n = 730) or not (tear not resected [TNR] group, n = 149). The restricted mean survival time ratios adjusted for patient characteristics and surgical details between the groups were calculated for all-cause mortality and aortic reoperation-free survival. The median follow-up time was 2.57 (interquartile range, 0.53-5.30) years.

RESULTS: For the majority of the patients in the TR group, the primary tear was located in the ascending aorta (83.6%). The reconstruction encompassed both the aortic root and the aortic arch in 7.4% in the TR group as compared with 0.7% in the TNR patients (P < .001). There were no significant differences in all-cause mortality (adjusted restricted mean survival time ratio, 1.01; 95% confidence interval, 0.92-1.12; P = .799) or reoperation-free survival (adjusted restricted mean survival time ratio, 0.98; 95% confidence interval, 0.95-1.02; P = .436) between the TR and TNR groups.

CONCLUSIONS: Primary tear resection alone does not determine the midterm outcome after surgery for acute type A aortic dissection. (Ann Thorac Surg 2022;114:492-501) (c) 2022 by The Society of Thoracic Surgeons.

We aimed to investigate a hypothesised association between daily mean temperature and the risk of surgery for acute type A aortic dissection (ATAAD). For the period of 1 January 2005 until 31 December 2019, we collected daily data on mean temperatures and date of 2995 operations for ATAAD at 10 Nordic cities included in the Nordic Consortium for Acute Type A Aortic Dissection (NORCAAD) collaboration. Using a two-stage time-series approach, we investigated the association between hot and cold temperatures relative to the optimal temperature and the rate of ATAAD repair in the selected cities. The relative risks (RRs) of cold temperatures (<=-5 degrees C) and hot temperatures (>= 21 degrees C) compared to optimal temperature were 1.47 (95% CI: 0.72-2.99) and 1.43 (95% CI: 0.67-3.08), respectively. In line with previous studies, we observed increased risk at cold and hot temperatures. However, the observed associations were not statistically significant, thus only providing weak evidence of an association.

Objectives: In Sweden, cloxacillin is recommended as the sole antibiotic prophylaxis for prevention of surgical site infections after cardiac surgery. Cutibacterium acnes, formerly Propionibacterium acnes, has been shown to be present in the surgical wound. Formerly an overlooked pathogen, there are increasing reports that C acnes can cause surgical site infections, including sternal wound infections. Cloxacillin may not be optimal for prevention of C acnes infection, therefore benzylpenicillin was added to our routine intraoperative prophylaxis in 2015. The aim of this study was to investigate the effect of benzylpenicillin on incidence of sternal wound infection.

Methods: We included 3920 consecutive patients that underwent cardiac surgery via median sternotomy at our centre from 2009 thru 2018. All patients were followed up two months postoperatively. The rate of sternal wound infection before and after 2015 were compared. Logistic multivariable analysis was used to adjust for potential confounders.

Results: The mean incidence of sternal wound infection that required surgical revision decreased from 4.7% to 1.7% after addition of benzylpenicillin (p < 0.001). Significant decrease was seen in sternal wound infections caused by Coagulase negative staphylococci, either alone (p<0.001) or concomitant with C acnes (p=0.008). Addition of benzylpenicillin remained independently associated with the reduction of sternal wound infections in the multivariable analysis (OR=0.36 CI=0.23-0.56, p<0.001).

Conclusions: Addition of benzylpenicillin was associated with a reduction in surgically treated infections and might be effective against infection caused by CoNS with and without co-infection by C acnes, although the exact underlying mechanism is unknown.

BACKGROUND

Atrial fibrillation (AF) is common after coronary artery bypass graft (CABG) surgery.

OBJECTIVE

To evaluate the incidence and recurrence rate of AF during 1 year after CABG surgery. We also aimed at calculating the AF burden and compare long-term intermittent vs continuous electrocardiogram (ECG) monitoring.

METHODS

Forty patients scheduled for CABG surgery were equipped with an implantable loop recorder (ILR). After discharge, they carried out handheld ECG 3 times daily during the first 30 postoperative days and during 2 weeks at 3 and 12 months. During hospital stay they were monitored with telemetry.

RESULTS

Altogether 27 of 40 (68%) patients were diagnosed with AF, 24 during the first month (21 in-hospital and 3 after discharge) and 3 during months 2-12. Three patients progressed into persistent AF. In addition, 17 patients had AF recurrence, 9 of them after the first 30 days. In patients with paroxysmal AF, the AF burden was low, 0.1% (interquartile range [IQR] 0.02%-0.3%). Patients with AF had higher CHA(2)DS(2)-VASc scores than non-AF patients: median 4 (IQR 3-4) and 3 (IQR 2-3.5), respectively, P = .006. The handheld ECG identified 45% (9/20) of the patients with AF episodes identified with continuous ECG monitoring with the ILR after discharge from hospital, P = .001.

CONCLUSIONS

Patients with AF during the postoperative hospitalization showed a high likelihood of recurrent AF, usually within 30 days. Continuous ECG monitoring with an ILR was superior to the handheld ECG for detecting patients with AF. The AF burden was low.

Objectives: To evaluate the distribution and impact of ABO blood groups on postoperative outcomes in patients undergoing surgery for acute type A aortic dissection (ATAAD).

Design: A total of 1144 surgical ATAAD patients from eight Nordic centres constituting the Nordic consortium for acute type A aortic dissection (NORCAAD) were analysed. Blood group O patients were compared to non-O subjects. The relative frequency of blood groups was assessed with t-distribution, modified for weighted proportions. Multivariable logistic regression was performed to identify independent predictors of 30-day mortality. Cox regression analyses were performed for assessing independent predictors of late mortality.

Results: There was no significant difference in the proportions of blood group O between the study populations in the NORCAAD registry and the background population (40.6 (95% CI 37.7-43.4)% vs 39.0 (95% CI 39.0-39.0)%). ABO blood group was not associated with any significant change in risk of 30-day or late mortality, with the exception of blood group A being an independent predictor of late mortality. Prevalence of postoperative complications was similar between the ABO blood groups.

Conclusions: In this large cohort of Nordic ATAAD patients, there were no associations between ABO blood group and surgical incidence or outcomes, including postoperative complications and survival.