Sleep-Disordered Breathing, Advanced Age, and Diabetes Mellitus Are Associated with De Novo Atrial Fibrillation after Cardiac Surgery

Background: Postoperative de novo atrial fibrillation (POAF) is one of the most frequently encountered complications following cardiac surgery. Despite the identification of several risk factors, the link between sleep-disordered breathing (SDB) and POAF has barely been examined. The objective of this prospective observational study was to determine whether severe SDB is associated with POAF in patients after elective coronary artery bypass grafting (CABG) surgery. Study design and methods: The incidence and preoperative predictors of in-hospital POAF were assessed in 272 patients undergoing CABG surgery at the University Medical Center Regensburg (Germany). In-hospital POAF was detected by continuous telemetry-ECG monitoring and 12-lead resting ECGs within the first seven postoperative days. POAF that occurred after hospital discharge within 60 days post CABG surgery was classified as post-hospital POAF and was ascertained by standardized phone interviews together with the patients' medical files, including routinely performed Holter-ECG monitoring at 60 days post CABG surgery. The night before surgery, portable SDB monitoring was used to assess the presence and type of severe SDB, defined by an apnea-hypopnea index ≥ 30/h. Results: The incidence of in-hospital POAF was significantly higher in patients with severe SDB compared to those without severe SDB (30% vs. 15%, p = 0.009). Patients with severe SDB suffered significantly more often from POAF at 60 days post CABG surgery compared to patients without severe SDB (14% vs. 5%, p = 0.042). Multivariable logistic regression analysis showed that severe SDB (odds ratio, OR [95% confidence interval, CI]: 2.23 [1.08; 4.61], p = 0.030), age ≥ 65 years (2.17 [1.04; 4.53], p = 0.038), and diabetes mellitus (2.27 [1.15; 4.48], p = 0.018) were significantly associated with in-hospital POAF. After additional adjustment for heart failure, the association between sleep apnea and postoperative atrial fibrillation was attenuated (1.99 [0.92; 4.31], p = 0.081). Conclusions: Amongst established risk factors, severe SDB was significantly associated with in-hospital POAF in patients undergoing CABG surgery. Whether SDB contributes to POAF independently of heart failure and whether risk for POAF may be alleviated by proper treatment of SDB merits further investigation.

Predictors of Nocturnal Hypoxemic Burden in Patients Undergoing Elective Coronary Artery Bypass Grafting Surgery

Background: Nocturnal hypoxemia has been linked to increased cardiovascular morbidity and mortality. Several common diseases, such as sleep-disordered breathing (SDB), heart failure (HF), obesity, and pulmonary disease, coincide with an elevated nocturnal hypoxemic burden with and without repetitive desaturations. Research question: This study aimed to evaluate the association of relevant common diseases with distinctive metrics of nocturnal hypoxemic burden with and without repetitive desaturations in patients undergoing coronary artery bypass grafting surgery. Study design and methods: In this subanalysis of the prospective observational study, CONSIDER-AF (NCT02877745) portable SDB monitoring was performed on 429 patients with severe coronary artery disease the night before cardiac surgery. Pulse oximetry was used to determine nocturnal hypoxemic burden, as defined by total recording time spent with oxygen saturation levels < 90% (T90). T90 was further characterized as T90 due to intermittent hypoxemia (T90desaturation) and T90 due to nonspecific and noncyclic SpO2-drifts (T90non-specific). Results: Multivariable linear regression analysis identified SDB (apnea-hypopnea-index ≥ 15/h; B [95% CI]: 6.5 [0.4; 12.5], p = 0.036), obesity (8.2 [2.5; 13.9], p = 0.005), and mild-to-moderate chronic obstructive pulmonary disease (COPD, 16.7 [8.5; 25.0], p < 0.001) as significant predictors of an increased nocturnal hypoxemic burden. Diseases such as SDB, obesity and HF were significantly associated with elevated T90desaturation. In contrast, obesity and mild-to-moderate COPD were significant modulators of T90non-specific. Interpretation: SDB and leading causes for SDB, such as obesity and HF, are associated with an increased nocturnal hypoxemic burden with repetitive desaturations. Potential causes for hypoventilation syndromes, such as obesity and mild-to-moderate COPD, are linked to an increased hypoxemic burden without repetitive desaturations. Clinical Trial Registration: ClinicalTrials.gov identifier: NCT02877745.

Ascending Aortic Pseudostenosis following the Classic Bentall Inclusion Technique

We present the case of a 52-year-old with a history of aortic valve replacement and replacement of the ascending aorta with the graft inclusion technique presenting with dizziness and collapse. Computed tomography and coronary angiography revealed pseudoaneurysm formation at the anastomotic site causing aortic pseudostenosis. Due to severe calcification of the graft inclusion surrounding the ascending aorta, we performed a redo ascending aortic replacement using a two-circuit cardiopulmonary bypass to avoid deep hypothermic cardiac arrest.

Long-Term Results of Patch Repair in Destructive Valve Endocarditis

OBJECTIVES

Treatment of destructive endocarditis with abscess formation is a surgical challenge and associated with significant morbidity and mortality. A root replacement is often performed in case of an annular abscess. This retrospective study was designed to assess the long-term outcome of extensive debridement and patch reconstruction as an alternative approach.

METHODS

Between November 2007 and November 2016, a selected group of 79 patients (29.6% of all surgical endocarditis cases) with native valve endocarditis (NVE, 53.2%) or prosthetic valve endocarditis (PVE, 46.8%) valve endocarditis underwent surgical therapy with extensive annular debridement and patch reconstruction. Their postoperative course, freedom from recurrent endocarditis, and survival at 1, 5, and 7 years were evaluated.

RESULTS

About two-thirds of patients were in a stable condition, one-third of patients were in a critical state. The median logistic EuroSCORE I was 17%. Infected tissue was removed, and defect closure was performed, either with autologous pericardium for small defects, or with bovine pericardium for larger defects. Overall, in-hospital mortality was 11.3% (NVE: 9.7%, PVE: 13.2%; p = 0.412). In single valve endocarditis survival at 1, 5, and 7 years was 81, 72, 72%, respectively for NVE, and 80, 57, 57%, respectively for PVE (p = 0.589), whereas in multiple valve endocarditis survival at 1, 5, and 7 years was 82, 82, 82% for NVE, and 61, 61, and 31%, respectively for PVE (p = 0.132). Confirmed late reinfection was very low.

CONCLUSION

Surgical treatment of destructive endocarditis with abscess formation using patch repair techniques offers acceptable early and long-term results. The relapse rate was low. PVE and involvement of multiple valves were associated with worse outcomes.

Omental Flap for Complex Sternal Wounds and Mediastinal Infection Following Cardiac Surgery

INTRODUCTION

Omental flap (OF) is a traditional surgical option to counteract severe postcardiotomy mediastinal infection and to cover extensive sternal defects. We reviewed our experience with omental flap transfer (OFT) in various clinical circumstances, in which omentoplasty may be considered by cardiac surgeons.

METHODS

Twenty-one patients, who underwent OFT from January 2012 to December 2021, were studied. The main indication was treatment of infected foreign material implants including vascular grafts and ventricular assist devices or prevention of its infection (16 patients). In five patients, an OFT was used to cure mediastinitis following deep sternal wound infection after median sternotomy.

RESULTS

All patients had a high surgical risk with 3 ± 1.9 previous sternotomies and a mean Euro Score II of 55.0 ± 20.1. OF was successful in its prophylactic or therapeutic purpose in all patients, no complications related to the operative procedure were noted, that is, no early or late flap failure and no herniation of abdominal organs occurred. In-hospital mortality was six patients as three patients each died from multiple organ dysfunction syndrome and cerebral hemorrhage. All fifteen patients discharged demonstrated rapid recovery, complete wound healing without fistula, and no late gastrointestinal complications. The mean follow-up of 18 months was uneventful.

CONCLUSION

OFT seems to be an excellent solution for extensive mediastinal and deep sternal wound infections.

Mid-Term Outcomes of a Hybrid Approach Involving Open Surgery Plus TEVAR of the Descending Aorta in the Treatment of Complex Type A Dissection

OBJECTIVES

Type A aortic dissection with true lumen collapse and malperfusion downstream is associated with a devastating prognosis. This study compares the clinical outcomes of two operative strategies for this disease: hybrid approach of ascending aorta (and hemiarch replacement) supplemented with retrograde stenting of the descending aorta (thoracic endovascular aortic repair [TEVAR]) and standard ascending aorta (and hemiarch) replacement without stent placement.

METHODS

From January 1, 2016 to December 31, 2019, 81 patients with type A aortic dissection were studied. The hybrid technique was applied in 30 patients (group 1), while 51 patients received standard surgical repair (group 2). Patient demographics, clinical and operative findings, postoperative outcome, follow-up interventions, and mid-term survival were analyzed.

RESULTS

Baseline characteristics were similar among the groups, except that more preoperative malperfusion was evident in group 1. The postoperative incidence of visceral malperfusion (0 vs. 15.7%, p = 0.02) and low cardiac output syndrome requiring extracorporeal membrane oxygenation support (3.3 vs. 19.6%, p = 0.04) was significantly less in group 1. In-hospital mortality was also significantly lower in group 1 as in group 2 (13.3 vs. 33.3%, p = 0.04). At follow-up, the need for secondary endovascular stenting (3.3 vs. 7.8%, p = 0.65) and surgical aortic reintervention (6.7 vs. 2.0%, p = 0.55) was comparable. One-year, 2-year, and 3-year survival rates were 83.3, 83.3, and 62.5% in group 1, and 58.7, 58.7, and 52.6% in group 2 (p = 0.05), respectively.

CONCLUSION

The combination of open surgical replacement of the ascending aorta (and hemiarch) with TEVAR of the descending aorta for true lumen compromise is a feasible treatment option for patients with type A aortic dissection and is associated with a better perioperative outcome and improved mid-term survival rate.

Outcome after veno‐arterial extracorporeal membrane oxygenation in elderly patients: a 14‐year single‐center experience

BACKGROUND

Use of veno-arterial extracorporeal membrane oxygenation (VA-ECMO) in elderly patients is controversial because of presumed poor outcome. Our primary aim was to determine the influence of advanced age on short- and long-term outcome; the secondary aim was to analyze risk factors for impaired outcome.

METHODS

Between January 2006 and June 2020, 645 patients underwent VA-ECMO implantation in our department. The patients were categorized into four groups:<50, 50-59.9, 60-69.9 and ≥70 years old. Data were retrospectively analyzed for short- and long-term outcome. Risk factors for in-hospital mortality and mortality during follow-up were assessed using multivariate regression analysis.

RESULTS

VA-ECMO support duration was comparable in all age groups (median 3 days). Weaning rates were 60.8%/n = 104 (<50 years), 51.4%/n = 90 (50-59.9 years), 58.8%/n = 107 (60-69.9), and 67.5%/n = 79 (≥70, p = 0.048). Hospital mortality was highest in the patients aged 50-59.9 years (68%/n = 119), but not in the elderly patients (60-69.9, ≥70:62.1%/n = 113, 58,1%/n = 68). At discharge, the cerebral performance category scores were superior in the patients <50 years. Multivariate logistic regression analysis revealed chronic kidney failure requiring hemodialysis, duration of cardiopulmonary resuscitation, and elevated blood lactate levels before VA-ECMO, but not age as predictors of in-hospital mortality. Cox's regression disclosed age as relevant risk factor for death during follow-up. The patients' physical ability was comparable in all age groups.

CONCLUSION

VA-ECMO support should not be declined in patients only because of advanced age. Mortality and neurological status at hospital discharge and during follow-up were comparable in all age groups.

Outcome after veno‐venous extracorporeal membrane oxygenation in elderly compared to younger patients: a 14‐year retrospective observational study

BACKGROUND

The outcome after veno-venous extracorporeal membrane oxygenation in elderly patients is supposed to be unsatisfactory. Our primary aim was to determine the influence of advanced age on short- and long-term outcomes; the secondary aim was to analyze risk factors for impaired outcomes.

METHODS

Between January 2006 and June 2020, 755 patients received V-V ECMO support at our department. Patients were grouped according to age (18-49.9, 50-59.9, 60-69.9, ≥70 years old), and then retrospectively analyzed for short- and long-term outcomes. Risk factors for in-hospital mortality and death during follow-up were assessed using multivariate regression analysis.

RESULTS

Duration of V-V ECMO support was comparable between all groups median (8-10 days, p = 0.256). Likewise, the weaning rate was comparable in all age groups 68.2%-76.5%; (p = 0.354), but in-hospital mortality was significantly climbing with increasing age (<50 years 30.1%/n = 91 vs. 50-59.9 years 37.1%/n = 73, vs. 60-69.9 years 45.6%/n = 78 vs. ≥70 years 51.8%/n = 44; p < 0.001). Older age groups also showed significantly reduced cerebral performance category scores. The multivariate logistic analysis yielded age, acute and chronic hemodialysis, bilirubin on day 1 of support, malignancy, and primary lung disease as relevant risk factors for in-hospital mortality. Age, coronary artery disease, presence of another primary lung disease, malignancy, and immunosuppression were risk factors for death during follow-up.

CONCLUSION

In V-V ECMO patients, advanced age is associated with more comorbidity, impaired short- and long-term outcome, and worse neurological outcome.

SAR296968, a Novel Selective Na+/Ca2+ Exchanger Inhibitor, Improves Ca2+ Handling and Contractile Function in Human Atrial Cardiomyocytes

Background: In reverse-mode, cardiac sodium-calcium exchanger (NCX) can increase the cytoplasmic Ca2+ concentration in response to high intracellular Na+ levels, which may contribute to diastolic contractile dysfunction. Furthermore, increased spontaneous Ca2+ release from intracellular stores can activate forward mode NCX. The resulting transient inward current causes delayed afterdepolarization (DAD)-dependent arrhythmias. Moreover, recently, NCX has been associated with impaired relaxation and reduced cardiac function in heart failure with preserved ejection fraction (HFpEF). Since NCX is upregulated in human chronic atrial fibrillation (AF) as well as heart failure (HF), specific inhibition may have therapeutic potential. Objective: We tested the antiarrhythmic, lusitropic and inotropic effects of a novel selective NCX-inhibitor (SAR296968) in human atrial myocardium. Methods and Results: Right atrial appendage biopsies of 46 patients undergoing elective cardiac surgery in a predominant HFpEF cohort (n = 24/46) were investigated. In isolated human atrial cardiomyocytes, SAR296968 reduced the frequency of spontaneous SR Ca2+ release events and increased caffeine transient amplitude. In accordance, in isolated atrial trabeculae, SAR296968 enhanced the developed tension after a 30 s pause of electrical stimulation consistent with reduced diastolic sarcoplasmic reticulum (SR) Ca2+ leak. Moreover, compared to vehicle, SAR296968 decreased steady-state diastolic tension (at 1 Hz) without impairing developed systolic tension. Importantly, SAR296968 did not affect the safety parameters, such as resting membrane potential or action potential duration as measured by patch clamp. Conclusion: The novel selective NCX-inhibitor SAR296968 inhibits atrial pro-arrhythmic activity and improves diastolic and contractile function in human atrial myocardium, which may have therapeutic implications, especially for treatment of HFpEF.

Increased NaV1.8 expression in patients with sleep-disordered breathing induces pro-arrhythmic activity

Background

Sleep-disordered breathing (SDB) is often associated with atrial fibrillation, but detailed mechanisms remain elusive. Interestingly, late Na current (late INa) has been shown to be increased in patients with SDB, while expression of cardiac Na channel NaV1.5 and peak Na current were decreased. Indeed, recent data demonstrated that enhanced NaV1.8-dependent late INa may also induce pro-arrhythmic activity.

Purpose

We tested whether Na-V1.8 expression and subsequent NaV1.8-dependent pro-arrhythmic activity are increased in patients with SDB.

Methods

We prospectively analysed 29 right atrial appendage biopsies of patients undergoing elective coronary artery bypass grafting. SDB was assessed using polygraphy in the preoperative night and an apnoea-hypopnea index (AHI) ≥15/h defined SDB. Micro-dissected atrial trabeculae were electrically field stimulated (at 1 Hz, 5 V for 50 ms, at 37°C) to elicit regular contractions. Trabecular arrhythmias were induced using 100 nM isoproterenol at [Ca]o of 3.5 mmol/L and pro-arrhythmic activity was scored from 0 (no arrhythmias) to 5 (salve). Sarcoplasmic reticulum Ca leak was estimated by the contractility after paused stimulation (at 2 Hz, normalized to before pause). To correlate functional and expression data for each individual patient, NaV1.8 mRNA expression was quantified in each trabeculum using qPCR.

Results

NaV1.8 mRNA expression was increased in patients with SDB, leading to a significant positive correlation with the severity of SDB (i.e. AHI, p=0.02, r2=0.22, Fig. 1A). Multivariate regression analysis revealed that this association was independent from age, sex, atrial fibrillation, heart failure, diabetes mellitus, and renal function (p=0.03, r2=0.35). Accordingly, selective NaV1.8 blockade with PF-01247324 (PF, 1 μM, 30 min) significantly improved post-pause contractility of isolated trabeculae from 1.69±0.31 to 2.95±0.54 in patients with SDB (p=0.001), whereas no significant improvement was observed in patients without SDB. This resulted in significant positive correlations between the PF-dependent improvement of post-pause contractility and both AHI (p=0.047, r2=0.19) and NaV1.8 mRNA expression (p=0.03, r2=0.17). Most importantly, we also observed a significant increase in arrhythmia severity in patients with SDB of 2.21±0.52 (vs. 1.00±0.49, p=0.03) that could be significantly reduced by selective NaV1.8 inhibition with PF to 0.25±0.18 (p=0.0008, Fig. 1B). In accordance, there was a significant positive correlation between arrhythmia severity and AHI (p=0.01, r2=0.28) that was abolished in the presence of PF (interaction analysis: p=0.ehab724.33141, r2=0.46).

Conclusion

In patients with SDB, enhanced NaV1.8 expression contribute to atrial pro-arrhythmic activity independent from comorbidities. Selective NaV1.8 inhibition may have therapeutic implications for patients with SDB.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): Part of the study was supported by grants from Philips Respironics (Murrysville, PA 15668) and the Medical Faculty at the University of Regensburg. Figure 1

Reliability of prognostic biomarkers after prehospital extracorporeal cardiopulmonary resuscitation with target temperature management

Background

Extracorporeal cardiopulmonary resuscitation (ECPR) performed at the emergency scene in out-of-hospital cardiac arrest (OHCA) can minimize low-flow time. Target temperature management (TTM) after cardiac arrest can improve neurological outcome. A combination of ECPR and TTM, both implemented as soon as possible on scene, appears to have promising results in OHCA. To date, it is still unknown whether the implementation of TTM and ECPR on scene affects the time course and value of neurological biomarkers.

Methods

69 ECPR patients were examined in this study. Blood samples were collected between 1 and 72 h after ECPR and analyzed for S100, neuron-specific enolase (NSE), lactate, D-dimers and interleukin 6 (IL6). Cerebral performance category (CPC) scores were used to assess neurological outcome after ECPR upon hospital discharge. Resuscitation data were extracted from the Regensburg extracorporeal membrane oxygenation database and all data were analyzed by a statistician. The data were analyzed using non-parametric methods. Diagnostic accuracy of biomarkers was determined by area under the curve (AUC) analysis. Results were compared to the relevant literature.

Results

Non-hypoxic origin of cardiac arrest, manual chest compression until ECPR, a short low-flow time until ECPR initiation, low body mass index (BMI) and only a minimal need of extra-corporeal membrane oxygenation support were associated with a good neurological outcome after ECPR. Survivors with good neurological outcome had significantly lower lactate, IL6, D-dimer, and NSE values and demonstrated a rapid decrease in the initial S100 value compared to non-survivors.

Conclusions

A short low-flow time until ECPR initiation is important for a good neurological outcome. Hypoxia-induced cardiac arrest has a high mortality rate even when ECPR and TTM are performed at the emergency scene. ECPR patients with a higher BMI had a worse neurological outcome than patients with a normal BMI. The prognostic biomarkers S100, NSE, lactate, D-dimers and IL6 were reliable indicators of neurological outcome when ECPR and TTM were performed at the emergency scene.

A decade of surgical therapy in an all-comer cohort with type A aortic dissection

BACKGROUND

We reported on a decade of aortic surgery for type A aortic dissection to assess surgical techniques employed and outcomes over time in an all-comer analysis of a mid-size university cardiosurgical center.

METHODS

From 2009 to 2018, 283 patients (189 males and 94 females, mean age 62 years, range 30-85 years), who underwent surgical therapy for type A aortic dissection in our institution were included in a retrospective statistical analysis.

RESULTS

Among all the patients, 55.5% of them were hemodynamically stable, 10.3% came in intubated. A neurological deficit was present in 18.9% of cases, extremity malperfusion was noted in 17.4%, and abdominal malperfusion detected in 8.2%. The extent of the aortic dissection corresponded to DeBakey type I in 88% of cases, a thoracoabdominal involvement was seen in 64%. In 51.9% of patients, only the ascending aorta replaced, another 40.6% of patients had proximal arch replacement too. A separate stent placement into the descending aorta was achieved in 13.4% of patients, during surgery (5.7%) or thereafter (7.7%). Overall survival to discharge was 79.5%. Most frequent complications were stroke and paralysis (15.2%), but only visceral malperfusion (OR 9.0) and heart failure mandating ECMO therapy (OR 29.5) were associated with significantly increased mortality.

CONCLUSIONS

Surgery for type A aortic dissection is still challenging. Along with the refinement of surgical techniques, the indication for the various procedures has moved from a simplified general strategy to a more individualized concept.

Extracorporeal Life Support in Postcardiotomy Cardiogenic Shock: A View on Scenario, Outcome, and Risk Factors in 261 Patients

BACKGROUND

Weaning failure from cardiopulmonary bypass, postoperative low cardiac output (LCO), and cardiopulmonary resuscitation (CPR) are common scenarios preceding extracorporeal life support (ECLS) implantation after cardiac surgery. The impact of these scenarios on short- and long-term outcome are not well described.

METHODS

Between March 2006 and December 2018, 261 patients received ECLS support after cardiac surgery. Data of patients with weaning failure (NW), postoperative LCO, and CPR leading to ECLS implantation were retrospectively analyzed regarding outcome. Risk factors for outcome after postcardiotomy ECLS were assessed by uni- or multivariate regression analysis.

RESULTS

Median duration of extracorporeal support was 5.5 ± 8.5 days. Overall mortality on ECLS was 39.1%. Scenario analysis revealed weaning failure from cardiopulmonary bypass in 40.6%, postoperative LCO in 24.5%, and postoperative CPR in 34.9% leading to initiation of ECLS. Most common cause of death was refractory LCO (25.3%). Overall follow-up survival was 23.7%. Survival after weaning and during follow-up in all subgroups was 9.2% (CPR), 5.0% (LCO), and 9.6% (NW), respectively. Uni- or multivariate regression analysis revealed age, aortic surgery, and vasopressor medication level on day 1 as risk for death on support, as well as postoperative renal failure, and body mass index (BMI) as risk factors for death during follow-up.

CONCLUSION

Mortality after postcardiotomy ECLS is high. Overall, outcome after CPR, NW, weaning failure and LCO is comparable. Postoperative resuscitation does not negatively affect outcome after postcardiotomy ECLS. Neurological status of ECLS survivors is good.

Central Sleep Apnea Predicts Pulmonary Complications After Cardiac Surgery

BACKGROUND

Postoperative major pulmonary complications (MPCs) continue to be leading causes of increased morbidity and death after cardiac surgery. Although various risk factors have been identified, reports on the association between sleep-disordered breathing (SDB) and postoperative MPCs remain inconclusive.

RESEARCH QUESTION

What is the incidence of the composite end point postoperative MPCs? What are predictors for postoperative MPCs in patients without SDB, with OSA, and with central sleep apnea (CSA) who undergo cardiac surgery?

STUDY DESIGN AND METHODS

In this subanalysis of the ongoing prospective observational study "Impact of Sleep-disordered breathing on Atrial Fibrillation and Perioperative complications in Patients undergoing Coronary Artery Bypass grafting Surgery (CONSIDER AF)," preoperative risk factors for postoperative MPCs were examined in 250 patients who underwent cardiac surgery. Postoperative MPCs (including respiratory failure, acute respiratory distress syndrome, pneumonia, or pulmonary embolism) were registered prospectively within the first seven postoperative days. Presence and type of SDB were assessed the night prior to surgery with the use of portable SDB-monitoring.

RESULTS

Patients with SDB experienced significantly more often postoperative MPCs than patients without SDB (24% vs 7%; P < .001). Multivariable logistic regression analysis showed that CSA (OR, 4.68 [95% CI, 1.78-12.26]; P = .002), heart failure (OR, 2.65 [95% CI, 1.11-6.31]; P = .028), and a history of transient ischemic attack or stroke (OR, 2.73 [95% CI, 1.07-6.94]; P = .035) were associated significantly with postoperative MPCs. Compared with patients without MPCs, those with postoperative MPCs had a significantly longer hospital stay (median days, 9 [25th/75th percentile, 7/13] vs 19 [25th/75th percentile, 11/38]; P < .001).

INTERPRETATION

Among established risk factors for postoperative MPCs, CSA, heart failure, and history of transient ischemic attack or stroke were associated significantly with postoperative MPCs. Our findings contribute to the identification of patients who are at high-risk for postoperative MPCs.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov identifier NCT02877745.

The oral Ca/calmodulin-dependent kinase II inhibitor RA608 improves contractile function and prevents arrhythmias in heart failure

Aims

Excessive activation of Ca/calmodulin‐dependent kinase II (CaMKII) is of critical importance in heart failure (HF) and atrial fibrillation. Unfortunately, lack of selectivity, specificity, and bioavailability have slowed down development of inhibitors for clinical use. We investigated a novel CaMKIIδ/CaMKIIɣ‐selective, ATP‐competitive, orally available CaMKII inhibitor (RA608) on right atrial biopsies of 119 patients undergoing heart surgery. Furthermore, we evaluated its oral efficacy to prevent deterioration of HF in mice after transverse aortic constriction (TAC).

Methods and results

In human atrial cardiomyocytes and trabeculae, respectively, RA608 significantly reduced sarcoplasmic reticulum Ca leak, reduced diastolic tension, and increased sarcoplasmic reticulum Ca content. Patch‐clamp recordings confirmed the safety of RA608 in human cardiomyocytes. C57BL6/J mice were subjected to TAC, and left ventricular function was monitored by echocardiography. Two weeks after TAC, RA608 was administered by oral gavage for 7 days. Oral RA608 treatment prevented deterioration of ejection fraction. At 3 weeks after TAC, ejection fraction was 46.1 ± 3.7% (RA608) vs. 34.9 ± 2.6% (vehicle), n = 9 vs. n = 12, P < 0.05, ANOVA, which correlated with significantly less CaMKII autophosphorylation at threonine 287. Moreover, a single oral dose significantly reduced inducibility of atrial and ventricular arrhythmias in CaMKIIδ transgenic mice 4 h after administration. Atrial fibrillation was induced in 6/6 mice for vehicle vs. 1/7 for RA608, P < 0.05, 'n − 1'  χ² test. Ventricular tachycardia was induced in 6/7 for vehicle vs. 2/7 for RA608, P < 0.05, 'n − 1'  χ² test.

Conclusions

RA608 is the first orally administrable CaMKII inhibitor with potent efficacy in human myocytes. Moreover, oral administration potently inhibits arrhythmogenesis and attenuates HF development in mice in vivo.

Increasing use of the Impella®-pump in severe cardiogenic shock: a word of caution

Impella® pumps are increasingly utilized in patients in cardiogenic shock. We report on a case series where Impella support was insufficient, and a switch to venoarterial extracorporeal membrane oxygenation (VA ECMO) became necessary. ECMO patients with previous Impella devices were identified utilizing our institutional ECMO database. Since 2014, 10 patients with a mean age of 62 ± 3 years were identified. Despite correct placement of all Impella pumps, cardiogenic shock persisted with progressive multi-organ failure (Impella type 2.5/CP n = 6/4 patients). Femoro-femoral VA ECMO was implanted percutaneously on the contralateral side with the Impella initially left on standby but retracted into the descending aorta for transport reasons after a mean support time of 20 ± 8 h. All patients were able to unload their heart by left ventricular ejection with a blood pressure amplitude of 15 ± 3 mmHg on VA ECMO support. After VA ECMO implantation haemodynamic parameters improved significantly within 24 h of support (mean serum lactate levels decreased from 92 ± 17 to 44 ± 10 mg/dl, P = 0.031). Survival to hospital discharge was 70%. These data indicate that the Impella 2.5® and CP® might not be sufficient in profound cardiogenic shock. Comparative studies are necessary to specify which patient population benefits from which type of circulatory support.

Predictors of delirium after cardiac surgery in patients with sleep disordered breathing

Introduction

Delirium ranks among the most common complications after cardiac surgery. Although various risk factors have been identified, the association between sleep disordered breathing (SDB) and delirium has barely been examined so far. Here, our objectives were to determine the incidence of post-operative delirium and to identify the risk factors for delirium in patients with and without SDB.

Methods

This subanalysis of the ongoing prospective observational study CONSIDER-AF (ClinicalTrials.govidentifierNCT02877745) examined risk factors for delirium in 141 patients undergoing cardiac surgery. The presence and type of SDB were assessed with a portable SDB monitor the night before surgery. Delirium was prospectively assessed with the validated Confusion Assessment Method for the Intensive Care Unit on the day of extubation and for a maximum of 3 days.

Results

Delirium was diagnosed in 23% of patients: in 16% of patients without SDB, in 13% with obstructive sleep apnoea and in 49% with central sleep apnoea. Multivariable logistic regression analysis showed that delirium was independently associated with age ≥70 years (OR 5.63, 95% CI 1.79–17.68; p=0.003), central sleep apnoea (OR 4.99, 95% CI 1.41–17.69; p=0.013) and heart failure (OR 3.3, 95% CI 1.06–10.35; p=0.039). Length of hospital stay and time spent in the intensive care unit/intermediate care setting were significantly longer for patients with delirium.

Conclusions

Among the established risk factors for delirium, central sleep apnoea was independently associated with delirium. Our findings contribute to identifying patients at high risk of developing post-operative delirium who may benefit from intensified delirium prevention strategies.

Conventional or minimized cardiopulmonary bypass support during coronary artery bypass grafting? - An analysis by means of perfusion and body mass index

The use of minimized cardiopulmonary bypass support to reduce the side effects of extracorporeal circulation is still contradictorily discussed. This study compares perfusion operated by conventional (CCPB) and minimized (MCPB) cardiopulmonary bypass support during coronary artery bypass grafting (CABG). This study includes the data of 5164 patients treated at our department between 2004 and 2014. Tissue perfusion during cardiopulmonary bypass support and cardiac arrest was assessed by means of body mass index, hemodilution, blood pressure with corresponding pump flow and venous oxygen saturation, serum lactate, and serum pH. Hemodilution was more pronounced after CCPB: hemoglobin had dropped to 4.47 ± 0.142 g/dL after CCPB and to 2.77 ± 0.148 g/dL after MCPB (P = 0.0022). Despite the higher pump flow in conventional circuits (4.86-4.95 L/min vs. 4.1-4.18 L/min), mean blood pressure was higher during minimized bypass support (53 ± 10 vs. 56 ± 13 mm Hg [aortic clamping], 57 ± 9 vs. 61 ± 12 mm Hg [34°C], 55 ± 9 vs.59 ± 11 mm Hg [aortic clamp removal], P < 0.0001) at all time points. Venous oxygen saturation remained on comparable levels of >70% during both conventional and minimized cardiopulmonary bypass support. The increase in serum lactate was more pronounced after CCPB (8.98 ± 1.28 vs. 3.66 ± 1.25 mg/dL, P = 0.0079), corresponding to a decrease in serum pH to acidotic levels (7.33 ± 0.06 vs. 7.35 ± 0.06, P < 0.0001). These effects were evident in all BMI ranges. Minimized cardiopulmonary bypass support provides efficient perfusion in all BMI ranges and is thus equivalent to conventional circuits.

Postoperative complications after elective coronary artery bypass grafting surgery in patients with sleep-disordered breathing

BACKGROUND

Sleep-disordered breathing (SDB) may increase the risk of postoperative complications in patients after cardiac surgery. This study evaluated the length of hospital stay as well as postoperative cardiac, respiratory, and renal complications after elective coronary artery bypass grafting (CABG) in patients without SDB, with central sleep apnea (CSA), or with obstructive sleep apnea (OSA).

METHODS

The presence and type of SDB had been assessed with polygraphic recordings in 100 patients the night before elective CABG surgery. SDB was defined as an apnea-hypopnea index (AHI) of ≥ 15/h. Prolonged length of hospital stay (LOS) and postoperative hemodynamic instability due to any cause were retrospectively evaluated as primary endpoints and cardiac, respiratory, and renal complications as secondary endpoints.

RESULTS

37% of patients had SDB, 14% CSA, and 23% OSA. LOS differed significantly between patients without SDB and those with CSA and OSA [median (25;75. percentile): 8.0 days (7.5;11.0) vs. 9.5 days (7.0;12.5) vs. 12.0 days (9.0;17.0), Kruskal-Wallis test between three groups: p = 0.023; OSA vs. no SDB: p = 0.005]. AHI was significantly associated with prolonged LOS [> 9 days; odds ratio (OR) (95% confidence interval): 1.047 (1.001;1.095), p = 0.044]. Prolonged need of vasopressors (≥ 48 h) was observed in 36% of patients without SDB, in 64% with CSA, and in 62% with OSA (p = 0.037). AHI was significantly associated with prolonged (≥ 48 h) need of vasopressors [OR (95% CI): 1.052 (1.002;1.104), p = 0.040], independent of any confounders.

CONCLUSIONS

SDB, particularly OSA, is associated with prolonged LOS after CABG, independent of known confounders. Prolonged LOS in patients with SDB may be due to increased postoperative hemodynamic instability due to any cause.

Long-term survival and quality of life after extracorporeal life support: a 10-year report

OBJECTIVES

Information is lacking about long-term survival and quality of life (QOL) after treating patients on extracorporeal life support.

METHODS

Outcome data were assessed by phone interviews, a QOL analysis using the EuroQol 5-dimensions questionnaire and a retrospective inquiry of the Regensburg ECMO Registry database for the decade 2006-2015. A statistical analysis was obtained by comparing patients with a cardiosurgical intervention (CS = 189 patients) with those without (w/oCS = 307 patients).

RESULTS

Survival to discharge in the w/oCS group was higher than that in the CS group (w/oCS: 41.7% vs CS: 29.5%; P  = 0.004). A Kaplan-Meier analysis showed a significant difference between both groups in favour of patients w/oCS (log rank P  = 0.02). This difference was no longer statistically significant after propensity score matching ( P  = 0.07). The 1- and 2-year survival rates of discharged patients were 67% and 50% in the w/oCS group vs 60% and 45% in the CS group (log rank P  = 0.29). Eighty-two patients answered the QOL questionnaire after a mean follow-up time of 4.2 ± 2.9 years. A total of 75% could handle their daily life; 57% were not limited in their usual activities. Mobility impairment was noted in 50%; 25% returned to work or school. There were no differences in the EuroQol 5-dimension indices between the patient groups. However, compared to a normative age-matched population, significantly lower indices were calculated.

CONCLUSIONS

Long-term survival rates in patients requiring extracorporeal life support are acceptable with a probable advantage for patients without an operation and a narrowed QOL. The results are promising and encouraging, but there is also a need for improvement.

Perforation of myocardial wall and great vessels after cardiovascular interventions-a 5-year analysis

Background

Less invasive procedures have replaced open surgical treatment in many cardiovascular disorders. During these interventions, iatrogenic cardiac perforation may ensue, which is a severe complication and requires immediate diagnostic assessment and treatment.

Methods

From March 2011 to April 2016, all patients referred to the Dept. of Cardio-thoracic Surgery with the diagnosis of iatrogenic perforation of myocardial wall or great vessels were included into the retrospective study. Complications during transapical transcutaneous aortic valve replacements (TAVR) procedures and percutaneous coronary intervention (PCI) were excluded from analysis. Symptoms, therapeutic strategy, intraoperative findings, and outcome were evaluated.

Results

Forty-four patients suffered from myocardial wall or vessel perforation. Most common site of perforation were right (n=26; 59.1%) and left (n=8; 18.2%) ventricle. Other structures were involved in ten cases (22.7%). Open surgical treatment was required in 27 cases (61.4%). Mortality after left and right ventricular laceration was 75.0% and 11.5%, respectively. Most common cause of death was cardiocirculatory failure (n=5).

Conclusions

Iatrogenic perforation of myocardial wall or central vessels during percutaneous interventional procedures is a rare but life-threatening complication. Despite immediate treatment efforts, mortality is high, particularly after left ventricular laceration.

NSE serum levels in extracorporeal life support patients-Relevance for neurological outcome?

BACKGROUND

Good neurological outcome is a major determinant after cardiac resuscitation. Extracorporeal life support may rapidly stabilize the patient, but cerebral ischemia remains a frequent complication relevant for further therapy. The aim of this study was to prove the value of NSE to indicate cerebral injury in patients with extracorporeal support after CPR.

METHODS

159 patients with CPR were included. NSE 48h peak levels and trends were tested for usability as predictive marker of brain injury, in-hospital mortality and long-term outcome.

RESULTS

Overall mortality in this cohort was 53.5%. Incidence of relevant brain injury was 34.6% with severe diffuse hypoxia in 23.2%. NSE peaks were comparable in patients with and without focal ischemia, but were increased in patients with severe diffuse hypoxic injury (p<0.0001). ROC analysis (area under the curve) of peak values indicating brain injury and in-hospital mortality was 0.73 (95% confidence interval [CI] 0.65-0.82) and 0.74 (95% CI 0.66-0.81), respectively. NSE increased in 56.6% of patients with a sensitivity of 0.82 (95% CI 0.69-0.92) and a specificity of 0.43 (CI 0.0.31-0.55) indicating cerebral injury. Sensitivity and specificity of NSE peak levels >100μg/L was 0.6 (CI 0.49-0.72) and 0.74 (CI 0.63-0.84). In-hospital mortality of patients with NSE >100μg/L was 71.7%. 46.2% of discharged patients are in good neurological status (cerebral performance category scale [CPC] 1-2). Patients with NSE <100μg/L showed an in-hospital mortality of 36.4%, and good neurological status in 67.9%.

CONCLUSION

NSE monitoring reliably indicates relevant cerebral injury in patients on extracorporeal support after cardiopulmonary resuscitation.

Early postoperative blood pressure and blood loss after cardiac surgery: A retrospective analysis

BACKGROUND

Increased blood loss after cardiac surgery is a risk factor for patient morbidity and mortality. Guidelines for postoperative haemodynamics management recommend normotensive blood pressure to avoid increased chest drain volumes. The aim of this study was to verify the correlation of early postoperative hypertension and blood loss in patients after cardiac surgery during the early postoperative period.

METHODS

Postoperative mean blood pressure values and chest drain volumes of 431 patients were registered by an intensive care monitoring system during first 60minutes after intensive care admission. Correlation between blood pressure and blood loss was calculated by linear regression analysis.

RESULTS

In the entire patient cohort and in various subgroup analyses (body-mass-index, type of surgery, comorbidity, emergency surgery, preoperative anticoagulation therapy) no association between early mean blood pressure >80mmHg and increased blood loss was evident in simple regression analysis. Merely, after aortic surgery a correlation of hypertension and blood loss was found. Multiple regression revealed postoperative INR values >1.5 and thrombocyte counts <100.000/nL to impact blood loss in contrast to postoperative hypertension.

CONCLUSION

Evidence for strict blood pressure management to reduce blood loss after cardiac surgery is scarce. Instead, in face of higher INR and low thrombocytes increasing postoperative blood loss, achieving and maintaining a physiological coagulation is essential.

Impact of cardiopulmonary bypass on acute kidney injury following coronary artery bypass grafting: a matched pair analysis

BACKGROUND

Postoperative Acute Kidney Injury (AKI) after coronary artery bypass grafting (CABG) is a common complication associated with significant morbidity and mortality. Cardiopulmonary bypass (CPB) is accepted to contribute to the occurrence of AKI and is of particular importance as it can be avoided by using the off-pump technique. However the renoprotective properties of off-pump (CABG) are controversial. This analysis evaluates the impact of cardiopulmonary bypass on renal function.

METHODS

A matched-pair analysis of 1428 patients undergoing coronary artery bypass grafting was conducted. The patients were stratified according to their preoperative renal function and to risk factors for postoperative AKI. The development of the glomerular filtration rate (GFR) from before surgery until hospital discharge was analyzed. Incidence of AKI were analyzed. Furthermore the impact of CPB duration on postoperative GFR was assessed.

RESULTS

The occurrence of AKI increases the risk of thirty-day mortality (odds ratio of 4.3). The postoperative GFR decreases significantly after coronary artery bypass grafting but does not differ between onpump and offpump CABG (60.2 ± 24.5 vs 60.7 ± 24.8; p=0.54). No difference regarding the incidence (26.6% vs 25%) and severity of AKI between cardiopulmonary bypass and the off-pump technique could be found. Duration of cardiopulmonary bypass does not correlate with the decline in postoperative glomerular filtration rate (Pearson Product Moment Correlation; p>0.050).

CONCLUSION

Neither the mere use nor duration of cardiopulmonary bypass proofed to be a risk factor for developing postoperative AKI in CABG patients with a comparable preoperative risk profile for postoperative renal dysfunction. Furthermore, the severity of postoperative AKI is not affected by the use of cardiopulmonary bypass.

Neuron-specific enolase serum levels predict severe neuronal injury after extracorporeal life support in resuscitation

OBJECTIVES

Extracorporeal life support (ECLS) is a rescue option in critically ill patients. Since fast available and appropriate for respiratory and circulatory failure, it is frequently applied in resuscitation scenarios. Neurological injury is a complication common in ECLS patients limiting outcome, particularly after resuscitation. In this study, the institutional ECLS database was used to correlate neuron-specific enolase (NSE) serum peak values with outcome of patients supported with venoarterial (VA) ECLS during cardiopulmonary resuscitation (CPR).

METHODS

From January 2011 to August 2012, 31 patients were provided with a VA ECLS during CPR (external cardiac massage). Serum NSE peaks were monitored and correlated with neurological outcome and hospital mortality. Patients were divided into two groups with mild-to-moderate and high NSE levels (cut-off value 100 μg/l).

RESULTS

High NSE levels were seen in 7 patients (mean 218 ± 155 μg/l) and mild-to-moderate levels in 24 patients (50 ± 23 μg/l, P = 0.0001). Duration of extracoporeal support was comparable in both groups (6.3 ± 7.5 vs 5.0 ± 4.5 days, P = n.s.). Patients with mild-to-moderate NSE levels were significantly older than those with high NSE levels (58 ± 16 vs 44 ± 15 years, P = 0.02). Six patients with high NSE levels (86%) developed severe neurological complications. Though 4 patients could be weaned from extracorporeal support, hospital mortality was 86% (6 patients). In contrast, patients with mild-to-moderate NSE levels had a hospital mortality of 46% (11 patients). Eighteen patients (75%) could be weaned from the device, and incidence of major neurological events was 29% (6 patients) only. Serum pH and lactate levels before ECLS implantation were significantly lower in patients with mild-to-moderate NSE values (pH: 7.23 ± 0.04 vs 6.93 ± 0.12, P = 0.039; lactate: 106 ± 11 vs 161 ± 16 mg/l, P = 0.023).

CONCLUSIONS

High NSE serum levels after ECLS correspond to poor neurological outcome and considerable mortality. Therefore, early neuroimaging is reasonable for determining therapeutic strategies in patients with high NSE peaks after resuscitation and extracorporeal support.

Delayed cardiac tamponade after open heart surgery - is supplemental CT imaging reasonable?

BACKGROUND

Cardiac tamponade is a severe complication after open heart surgery. Diagnostic imaging is challenging in postoperative patients, especially if tamponade develops with subacute symptoms. Hypothesizing that delayed tamponade after open heart surgery is not sufficiently detected by transthoracic echocardiography, in this study CT scans were used as standard reference and were compared with transthoracic echocardiography imaging in patients with suspected cardiac tamponade.

METHOD

Twenty-five patients after open heart surgery were enrolled in this analysis. In case of suspected cardiac tamponade patients underwent both echocardiography and CT imaging. Using CT as standard of reference sensitivity, specificity, positive and negative predictive values of ultrasound imaging in detecting pericardial effusion/hematoma were analyzed. Clinical appearance of tamponade, need for re-intervention as well as patient outcome were monitored.

RESULTS

In 12 cases (44%) tamponade necessitated surgical re-intervention. Most common symptoms were deterioration of hemodynamic status and dyspnea. Sensitivity, specificity, positive and negative predictive values of echocardiography were 75%, 64%, 75%, and 64% for detecting pericardial effusion, and 33%, 83%, 50, and 71% for pericardial hematoma, respectively. In-hospital mortality of the re-intervention group was 50%.

CONCLUSION

Diagnostic accuracy of transthoracic echocardiography is limited in patients after open heart surgery. Suplemental CT imaging provides rapid diagnostic reliability in patients with delayed cardiac tamponade.

Donor brain death exacerbates complement-dependent ischemia/reperfusion injury in transplanted hearts

BACKGROUND

Brain death (BD) can immunologically prime the donor organ and is thought to lead to exacerbated ischemia/reperfusion injury after transplantation. Using a newly developed mouse model of BD, we investigated the effect of donor BD on posttransplantation cardiac ischemia/reperfusion injury. We further investigated the therapeutic effect of a targeted complement inhibitor in recipients of BD donor hearts and addressed the clinical relevance of these studies by analyzing human heart biopsies from BD and domino (living) donors.

METHODS AND RESULTS

Hearts from living or BD donor C57BL/6 mice were transplanted into C57BL/6 or BALB/c recipients. Recipient mice were treated with the complement inhibitor CR2-Crry or vehicle control (n=6). Isografts were analyzed 48 hours after transplantation for injury, inflammation, and complement deposition, and allografts were monitored for graft survival. Human cardiac biopsies were analyzed for complement deposition and inflammatory cell infiltration. In the murine model, donor BD exacerbated ischemia/reperfusion injury and graft rejection, as demonstrated by increased myocardial injury, serum cardiac troponin, cellular infiltration, complement deposition, inflammatory chemokine and cytokine levels, and by decreased graft survival. CR2-Crry treatment of recipients significantly reduced all measured outcomes in grafts from both BD and living donors compared with controls. Analysis of human samples documented the relevance of our experimental findings and revealed exacerbated complement deposition and inflammation in grafts from BD donors compared with grafts from living donors.

CONCLUSIONS

BD exacerbates posttransplantation cardiac ischemia/reperfusion injury in mice and humans and decreases survival of mouse allografts. Furthermore, targeted complement inhibition in recipient mice ameliorates BD-exacerbated ischemia/reperfusion injury.

Effects of brain death on organ quality and transplant outcome

The inferiority of organs from brain dead donors is reflected by impaired graft survival and patient outcome. Brain death effects hemodynamic stability, hormonal changes, and neuroimmunologic effects and unleashes a cascade of inflammatory events. Despite considerable efforts in experimental and clinical research, most of the mechanisms linked to brain death are only appreciated on a descriptive level. This overview presents our current understanding of the pathophysiology and consequences of brain death on organ injury and summarizes available therapeutic interventions.

Inflammatory immune responses in a reproducible mouse brain death model

BACKGROUND

Brain death impairs donor organ quality and accelerates immune responses after transplantation. Detailed aspects of immune activation following brain death remain unclear. We have established a mouse model and investigated the immediate consequences of brain death and anesthesia on immune responses.

METHODS

C57JBl/6 mice (n=6/group) were anesthetized with isoflurane (ISF) or ketamine/xylazine (KX); subsequently, animals underwent brain death induction and were followed for 3h under continuous ventilation. Blood pressure was monitored continuously and animals were resuscitated with normal saline to achieve normotension. Immune activation in brain dead animals was analyzed by IFNγ-ELispot, MLR, and flow-cytometry. Sham-operated and naïve animals served as controls.

RESULTS

Blood pressure remained stable in both BD/KX and BD/ISF animals during the 3h observation time. Brain death was linked to systemic immune activation: IFNγ-expression of splenocytes and lymphocyte proliferation rates was significantly elevated subsequent to brain death (p<0.02, <0.01); T-cell activation markers CD28 and CD69 had increased in brain dead animals (p<0.03, <0.02). Isoflurane treatment in sham controls throughout the observation period (3.5h) revealed anesthesia associated IFNγ-expression and lymphocyte activation which were not observed when animals were treated with ketamine/xylazine (p<0.04, <0.009).

CONCLUSIONS

This study reports on a reproducible and hemodynamically stable brain death mouse model. Hemodynamic stability was not impacted through either isoflurane or ketamine/xylazine induction. Of clinical relevance, prolonged anesthesia with isoflurane had been linked to pro-inflammatory cytokine activation. Brain death caused systemic immune activation in organ donors.

Consequences of transplant quality on chronic allograft nephropathy

Using kidneys from expanded-criteria donors to alleviate organ shortage has raised concern on reduced transplant outcomes. In this paper, we review how critical donor-related factors such as donor age, brain death, and consequences of ischemia-reperfusion injury (IRI) determine graft quality and impact chronic allograft nephropathy. We propose that combinatorial effects of organ-intrinsic features associated with increasing age and unspecific injuries related to brain death and IRI will impact innate and adaptive immune responses. Future research will need to explore avenues to optimize donor management, organ preservation, adapted immunosuppressive strategies, as well as modifications of the allocation of suboptimal allografts.

Machine perfusion or cold storage in organ transplantation: indication, mechanisms, and future perspectives

Most organs are currently preserved by cold storage (CS) prior to transplantation. However, as more so called marginal donor organs are utilized, machine perfusion has regained clinical interest. Recent studies have demonstrated advantages of pulsatile perfusion over CS preservation for kidney transplantation. However, it remains unclear whether there is a significant benefit of one preservation method over the other in general, or, whether the utilization of particular preservation approaches needs to be linked to organ characteristics. Proposed protective mechanisms of pulsatile perfusion remain largely obscure. It can be speculated that pulsatile perfusion may not only provide nutrition and facilitate the elimination of toxins but also trigger protective mechanisms leading to the amelioration of innate immune responses. Those aspects may be of particular relevance when utilizing grafts with suboptimal quality which may have an increased vulnerability to ischemia/reperfusion injury and compromised repair mechanisms. This review aims to enunciate the principles of organ perfusion and preservation as they relate to indication, aspects of organ protection and to highlight future developments.

Direct evidence of endothelial injury during cardiopulmonary bypass by demonstration of circulating endothelial cells

Endothelial activation is considered a key process in the development of a whole body inflammatory response secondary to cardiopulmonary bypass (CPB). Increased levels of a multitude of soluble mediators have been described as being released during and after cardiac surgery. Circulating endothelial cells have recently been established as a novel marker of endothelial damage in a variety of vascular disorders. Blood samples from 20 patients undergoing elective coronary artery bypass surgery were obtained preoperatively and 1, 6, 12, 24, and 48 h after termination of CPB. Control samples were obtained from ten healthy volunteers. Circulating endothelial cells (CEC) were isolated with immunomagnetic anti-CD146-coated Dynabeads, and counted in a Nageotte chamber. Low numbers of CEC were observed in healthy control volunteers (12 +/- 6 cells/mL; median: 9 cells/mL). CEC numbers were already significantly elevated in all patients before CPB, and there was a further significant increase after weaning from CPB (maximum increase at 6 h after CPB: 73 +/- 30 cells/mL; range: 30-153 cells/mL, p < 0.001). The number of CEC provides further and direct evidence that CPB is associated with a pronounced endothelial injury and/or damage. CEC appear to be most useful markers for vascular endothelial activation because they are specific, stable, and circulating components of injured vessel wall.

Endothelial apoptosis and circulating endothelial cells after bypass grafting with and without cardiopulmonary bypass

OBJECTIVE

We compared profiles of the numbers of circulating endothelial cells (CEC) and the apoptosis-inducing capacity of serum samples on human endothelial cells (hEC) in on-pump and off-pump coronary artery bypass grafting (CABG) patients.

METHODS

Blood samples from 30 patients undergoing CABG (randomly assigned to two groups: 15 patients off-pump and 15 on-pump (cardiopulmonary bypass, CPB)) were collected after induction of anesthesia (preoperatively), at weaning from CPB/end of bypass grafting (0 h), and 1, 6, 12, 24, and 48 h afterwards. CEC were isolated with immunomagnetic anti-CD146-coated Dynabeads, and counted in a Nageotte chamber. The apoptosis-inducing activity of serum samples on hEC was examined by a tissue culture assay system. Apoptotic and normal cells were identified using phase contrast/fluorescence microscopy after DNA dye staining.

RESULTS

CEC numbers and proportions of apoptotic hEC were significantly elevated during and after surgery in both groups (p<0.01). Compared with the on-pump group, CEC and proportions of apoptotic hEC were significantly lower (p=0.04 and p=0.03, respectively) in patients having CABG performed off-pump. Starting at comparable baseline levels, the mean CEC-number was highest at 6h postoperatively with 81.9 ml(-1) (range, 44-141) for on-pump patients and 63.3 ml(-1) (range, 48-105) for off-pump patients. hEC apoptosis peaked also at T4: 16.5+/-2.8% versus 11.3+/-2.2%. In both groups, CEC numbers and proportions of endothelial apoptosis were still elevated at 48 h after surgery.

CONCLUSION

The number of circulating endothelial cells and apoptotic endothelial cell death are markers of endothelial activation and damage during CABG. This study provides evidence that CABG with the use of CPB in comparison to OPCAB surgery is associated with a significantly more pronounced endothelial response in the immediate postoperative period.