Background: The measurement of serum cardiac troponin T concentration (cTnT) after aortic valve replacement (AVR) provides the opportunity to assess the degree of myocardial damage and may have some prognostic value. Aim: To determine whether elevated troponin level is related to patient outcome. Methods: We investigated patient outcome and postoperative serum concentration of troponin T in 79 patients who underwent AVR. Serum levels of cTnT were measured within 24 h of AVR. We searched for the occurrence of subsequent adverse events i.e. requirement for intraaortic ballon pump (IABP) or inotropic support, prolonged Intensive Care Unit (ICU) stay, and in-hospital death. Results: Serum concentration of cTnT after AVR increased significantly compared to the preoperative value. We found significant positive correlations between aortic cross-clamp time (r = 0.23, p = 0.04), cardiopulmonary bypass time (r = 0.4, p = 0.00029), duration of the surgery (r = 0.30, p = 0.008), and postoperative cTnT level. Three (4%) patients required IABP support, 37 (46%) patients required inotropic support, and 11 (14%) patients had a prolonged ICU stay (> 48 h). Thirty eight (48%) patients required either inotropic support or IABP insertion. At least one adverse event occurred in 44 (56%) patients. Median postoperative serum cTnT concentration was 0.31 ng/mL (interquartile range 0.23-0.60 ng/mL). We failed to find a statistically significant difference in postoperative cTnT level between patients with and without adverse events. According to multiple logistic regression analysis, the postoperative serum level of troponin T was not independently associated with adverse patient outcome. Diabetes mellitus, patient age and left ventricular ejection fraction below 50% were significant independent predictors of adverse events after AVR. The area under receiver operating curve (AUROC) for postoperative serum troponin T concentration as a determinant of various adverse outcomes was never significantly different from 0.50. Conclusions: Serum cTnT concentration is frequently - if not universally - elevated after AVR. Serum level of troponin T measured on the first postoperative morning is a poor predictor of patient outcome after AVR and should not be relied on when planning postoperative care.

Background: Remote preconditioning was showed to be a potent protective phenomenon in many animals. Several studies aimed to demonstrate it was feasible in humans by trying to show its protective effect during cardiac surgery. Of these studies some small studies and one bigger trial were positive while two other bigger studies showed no effectiveness of remote preconditioning as assessed by levels of postoperatively released cardiac markers. Recently two large clinical trials also failed to prove the benefit of remote preconditioning in cardiac surgery. No study showed that remote preconditioning actually increases resistance of human myocardium to standardized ischemic and reperfusion stimulus in experimental settings. In animal studies remote preconditioning was showed to improve mitochondrial function and structure however such data on human myocardium are scarce. Aim: The aim of the study is to determine whether remote preconditioning protects human myocardium against ischemia-reperfusion injury in both in vivo and in vitro conditions. Methods: The trial is designed as a single center, double-blinded, sham-controlled trial of 120 patients. We randomize (1:1) patients referred for coronary artery bypass grafting for stable coronary artery disease to remote preconditioning or “sham” intervention. The remote preconditioning is obtained by 3 cycles of 5min inflation and 5 min deflation of blood pressure cuff on the right arm. Postoperative course including myocardial enzymes profile will be analyzed. Moreover, in the in-vitro arm the clinically preconditioned myocardium will be assessed for function, mitochondria structure and mitochondria dependent apoptosis. The informed consent of all patients is obtained before enrollment into the study by the investigator. The study conforms to the spirit and the letter of the declaration of Helsinki. Conclusions: In case the effect of remote preconditioning is not measurable in ex-vivo assessment, the future attempt at implementing this phenomenon in clinical practice may be futile and should not be continued until the effect can be confirmed in controlled experimental setting. The study might therefore indicate future directions in trials of clinical implementation of remote preconditioning. Trial Registration: Clinical Trials Register (Clinicaltrials.gov) identifier: NCT01994707. The study was approved by Institutional Review Board of Medical University of Silesia (KNW/0022/KB1/160/12). Background: Remote preconditioning was showed to be a potent protective phenomenon in many animals. Several studies aimed to demonstrate it was feasible in humans by trying to show its protective effect during cardiac surgery. Of these studies some small studies and one bigger trial were positive while two other bigger studies showed no effectiveness of remote preconditioning as assessed by levels of postoperatively released cardiac markers. Recently two large clinical trials also failed to prove the benefit of remote preconditioning in cardiac surgery. No study showed that remote preconditioning actually increases resistance of human myocardium to standardized ischemic and reperfusion stimulus in experimental settings. In animal studies remote preconditioning was showed to improve mitochondrial function and structure however such data on human myocardium are scarce. Aim: The aim of the study is to determine whether remote preconditioning protects human myocardium against ischemia-reperfusion injury in both in vivo and in vitro conditions. Methods: The trial is designed as a single center, double-blinded, sham-controlled trial of 120 patients. We randomize (1:1) patients referred for coronary artery bypass grafting for stable coronary artery disease to remote preconditioning or “sham” intervention. The remote preconditioning is obtained by 3 cycles of 5min inflation and 5 min deflation of blood pressure cuff on the right arm. Postoperative course including myocardial enzymes profile will be analyzed. Moreover, in the in-vitro arm the clinically preconditioned myocardium will be assessed for function, mitochondria structure and mitochondria dependent apoptosis. The informed consent of all patients is obtained before enrollment into the study by the investigator. The study conforms to the spirit and the letter of the declaration of Helsinki. Conclusions: In case the effect of remote preconditioning is not measurable in ex-vivo assessment, the future attempt at implementing this phenomenon in clinical practice may be futile and should not be continued until the effect can be confirmed in controlled experimental setting. The study might therefore indicate future directions in trials of clinical implementation of remote preconditioning. Trial Registration: Clinical Trials Register (Clinicaltrials.gov) identifier: NCT01994707. The study was approved by Institutional Review Board of Medical University of Silesia (KNW/0022/KB1/160/12).

No experimental study has shown that the myocardium of a remotely preconditioned patient is more resistant to a standardized ischaemic/hypoxic insult. This was a single-centre randomized (1:1), double-blinded, sham-controlled, parallel-group study. Patients referred for elective coronary bypass surgery were allocated to either remote ischaemic preconditioning (3 cycles of 5-min ischaemia/5-min reperfusion of the right arm using a blood pressure cuff inflated to 200 mmHg) or sham intervention. One hundred and thirty-four patients were recruited, of whom 10 dropped out, and 4 were excluded from the per-protocol analysis. The right atrial trabecula harvested on cannulation for cardiopulmonary bypass was subjected to 60 min of simulated ischaemia and 120 min of reoxygenation in an isolated organ experiment. Postoperative troponin T release and haemodynamics were assessed in an in vivo study. The atrial trabeculae obtained from remotely preconditioned patients recovered 41.9% (36.3-48.3) of the initial contraction force, whereas those from non-preconditioned patients recovered 45.9% (39.1-53.7) (P = 0.399). Overall, the content of cleaved poly (ADP ribose) polymerase in the right atrial muscle increased from 9.4% (6.0-13.5) to 19.1% (13.2-23.8) (P < 0.001) after 1 h of ischaemia and 2 h of reperfusion in vitro. The amount of activated Caspase 3 and the number of terminal deoxynucleotidyl transferase dUTP nick end labeling-positive cells also significantly increased. No difference was observed between the remotely preconditioned and sham-treated myocardium. In the in vivo trial, the area under the curve for postoperative concentration of troponin T over 72 h was 16.4 ng⋅h/ml (95% confidence interval 14.2-18.9) for the remote ischaemic preconditioning and 15.5 ng⋅h/ml (13.4-17.9) for the control group in the intention-to-treat analysis. This translated into an area under the curve ratio of 1.06 (0.86-1.30; P = 0.586). Remote ischaemic preconditioning with 3 cycles of 5-min ischaemia/reperfusion of the upper limb before cardiac surgery does not make human myocardium more resistant to ischaemia/reperfusion injury. NCT01994707.

Background: Postoperative atrial fibrillation (POAF) after cardiac surgery is common and clinically relevant, yet optimal postdischarge ECG surveillance remains undefined. We assessed the incidence of POAF after isolated coronary artery bypass grafting (CABG) and surgical aortic valve replacement (SAVR) using a dual-modality ambulatory strategy. Methods: In an exploratory, single-center study, consecutive adults without pre-operative AF undergoing elective isolated CABG or SAVR received dual-modality monitoring after discharge: continuous patch-Holter for ~10 days and a patient-activated single-lead recorder for up to 30 days. Early POAF was AF/AFl during index hospitalization; late POAF was first AF/AFL detected postdischarge by either modality. Results: Fifty-five patients were enrolled (CABG 30 [54.5%], SAVR 25 [45.5%]; mean age 64.6 ± 9.8 years; 38.2% women). Early POAF occurred in 10/49 (20.4%); late POAF was detected in 21/55 (38.2%). By modality, late AF was identified on the 10-day Holter in 11/51 (21.6%) and on the 30-day recorder in 19/51 (37.3%). Cumulative detection reached 20.0% by day 7, 30.9% by day 10, and 38.2% thereafter, demonstrating that a substantive proportion of late POAF occurred after day 10, and 19/21 (90%) were captured by event monitoring. Female sex was independently associated with late POAF (OR 3.70, 95% CI 1.17–11.72); longer aortic cross-clamp time was related to late POAF in the SAVR subset, while larger LA size was related to POAF incidence in the CABG group. Early (in-hospital) POAF was associated with subsequent late POAF (p = 0.025). The difference in late POAF frequency between CABG and SAVR (33.3% vs. 44.0%; p = 0.42) was not significant. Conclusions: Among patients without prior AF undergoing CABG or SAVR, late POAF is frequent and often manifests beyond 10 days after discharge. Extending ambulatory surveillance to 30 days—or adopting a 10-day continuous plus patient-activated to day 30 hybrid—materially improves case finding and should be considered in routine postoperative pathways.