COVID-19 infection in patients with history of pediatric heart transplant in Germany, Austria, and Switzerland

COVID-19 is a heterogenous infection-asymptomatic to fatal. While the course of pediatric COVID-19 infections is usually mild or even asymptomatic, individuals after adult heart transplantation are at high risk of a severe infection. We conducted a retrospective, multicenter survey of 16 pediatric heart transplant centers in Germany, Austria and Switzerland to evaluate the risk of a severe COVID-19 infection after pediatric heart transplantation between 02/2020 and 06/2021. Twenty-six subjects (11 male) with a median age of 9.77 years at time of transplantation and a median of 4.65 years after transplantation suffered from COVID-19 infection. The median age at time of COVID-10 infection was 17.20 years. Fourteen subjects had an asymptomatic COVID-19 infection. The most frequent symptoms were myalgia/fatigue (n = 6), cough (n = 5), rhinitis (n = 5), and loss of taste (n = 5). Only one subject showed dyspnea. Eleven individuals needed therapy in an outpatient setting, four subjects were hospitalized. One person needed oxygen supply, none of the subjects needed non-invasive or invasive mechanical ventilation. No specific signs for graft dysfunction were found by non-invasive testing. In pediatric heart transplant subjects, COVID-19 infection was mostly asymptomatic or mild. There were no SARS-CoV-2 associated myocardial dysfunction in heart transplant individuals.

Turbulence in surgical suction heads as detected by MRI

BACKGROUND

Blood loss is common during surgical procedures, especially in open cardiac surgery. Allogenic blood transfusion is associated with increased morbidity and mortality. Blood conservation programs in cardiac surgery recommend re-transfusion of shed blood directly or after processing, as this decreases transfusion rates of allogenic blood. But aspiration of blood from the wound area is often associated with increased hemolysis, due to flow induced forces, mainly through development of turbulence.

METHODS

We evaluated magnetic resonance imaging (MRI) as a qualitative tool for detection of turbulence. MRI is sensitive to flow; this study uses velocity-compensated T1-weighted 3D MRI for turbulence detection in four geometrically different cardiotomy suction heads under comparable flow conditions (0-1250 mL/min).

RESULTS

Our standard control suction head Model A showed pronounced signs of turbulence at all flow rates measured, while turbulence was only detectable in our modified Models 1-3 at higher flow rates (Models 1 and 3) or not at all (Model 2).

CONCLUSIONS

The comparison of flow performance of surgical suction heads with different geometries via acceleration-sensitized 3D MRI revealed significant differences in turbulence development between our standard control Model A and the modified alternatives (Models 1-3). As flow conditions during measurement have been comparable, the specific geometry of the respective suction heads must have been the main factor responsible. The underlying mechanisms and causative factors can only be speculated about, but as other investigations have shown, hemolytic activity is positively associated with degree of turbulence. The turbulence data measured in this study correlate with data from other investigations about hemolysis induced by surgical suction heads. The experimental MRI technique used showed added value for further elucidating the underlying physical phenomena causing blood damage due to non-physiological flow.

Expression and prognostic impact of DNA-PK in human lung cancer

Among all cancer patient's lung cancer is the leading cause of death. Prognostic biomarkers continue to be investigated for the detection and stratification of lung cancer for clinical use. The DNA-dependent protein kinase is involved in mechanisms of DNA damage repair. Deregulation and overexpression of DNA-dependent protein kinase is associated with poor prognosis in various tumor entities. In this study, we investigated the expression of DNA-dependent protein kinase in relation to clinicopathological features and overall survival in patients with lung cancer. By immunohistochemistry, expression of DNA-dependent protein kinase was analyzed in 205 cases of lung cancer; 95 cases of adenocarcinoma, 83 cases of squamous cell lung carcinoma and 27 cases of small cell lung cancer and correlated with clinicopathological characteristics as well as patient's overall survival. In patients with adenocarcinoma, a significant correlation between strong expression of DNA-dependent protein kinase and worse overall survival was found. No significant association was observed in patients with squamous cell lung carcinoma and small cell lung cancer. Strong detection of DNA-dependent protein kinase expression was most evident in small cell lung cancer (81.48 %), followed by squamous cell lung carcinoma (62.65 %) and adenocarcinoma (61.05 %). In our study, expression of DNA-dependent protein kinase was associated with poor overall survival in patients with adenocarcinoma. DNA-dependent protein kinase could serve as a new prognostic biomarker.

Expression and prognostic impact of CD49b in human lung cancer

Lung cancer remains the worldwide leading cause of cancer-related death. Currently, prognostic biomarkers for the detection and stratification of lung cancer are being investigated for clinical use. The surface protein cluster of differentiation 49b (CD49b) plays an important role in promoting cell proliferation and invasion in different tumor entities and blocking CD49b improved the tumor immune response. Overexpression of CD49b has been associated with unfavorable survival rates in several malignant tumor entities, such as prostate cancer, gastric cancer and colon cancer. Therefore, we aimed to analyze the protein expression of CD49b in patients with different types of lung cancer and additionally to identify the influence of CD49b on clinicopathological characteristics and overall survival.Expression levels of CD49b were retrospective analyzed by immunohistochemistry in 92 cases of pulmonary adenocarcinoma (AC), 85 cases of squamous cell lung carcinoma (SQCLC) and 32 cases of small cell lung cancer (SCLC) and correlated with clinicopathological characteristics and patients' overall survival.A strong expression of CD49b was most seen in SQCLC (78%), followed by AC (48%) and SCLC (9%). All patients combined, strong expression of CD49b correlated significantly with poorer overall survival. However, an increased expression of CD49b correlated significantly with a poorer survival rate only in SQCLC. In AC and SCLC, no significant correlation could be demonstrated in this regard.In our study, CD49b expression was associated with poor overall survival in patients with SQCLC. Accordingly, CD49b could serve as a new prognostic biomarker and, moreover, be a potential new drug target in SQCLC.

Re-exploration Early after Cardiac Surgery in Adults: The Importance of Bleeding-Related Complications

BACKGROUND

Re-explorations soon after cardiac surgery are mostly related to bleeding or unclear hemodynamic situations possibly related to heart compression resulting from pericardial hematoma. This condition has a significant impact on mortality, morbidity, and costs. The aim of this study was to analyze indications and outcomes of re-exploration for bleeding or pericardial tamponade early after cardiac surgery in adults.

METHODS

The clinical data of 4790 consecutive adult patients who underwent cardiac surgery in our institution from January 2011 to May 2016 were retrospectively analyzed.

RESULTS

We identified 331 re-explorations performed in 231 patients. Sixty-seven of these patients had >1 re- exploration. In most cases (88%), repeat sternotomy was performed. Most procedures (57%) were performed within the first 48 hours. In two-thirds of re-explorations, active bleeding or pericardial hematoma was verified. In the remaining cases, neither bleeding nor significant pericardial hematoma leading to tamponade was found. Among the cases with active bleeding causes, the most bleeding sites were found to be at the coronary anastomosis and the epicardial exposure harvesting site, as well as from the side branches of bypass grafts and intercostal arteries.

CONCLUSIONS

The incidence of re-exploration after cardiac surgery in adults was low (4.8%). In about two-thirds of the cases, active bleeding or significant pericardial hematoma was found. The most common bleeding causes were the easiest to treat.

Efficacy and safety of non-transvenous cardioverter defibrillators in infants and young children

BACKGROUND

Implantable cardioverter defibrillators (ICD) protect from sudden cardiac death (SCD). In infants and young children, ICD implantation and programming is challenging due to small body size, elevated heart rates, and high physical activity.

PURPOSE

We report our experience applying a non-transvenous ICD (NT-ICD) system to infants and children < 12 years of age and < 45-kg body weight.

METHODS

Between 07/2004 and 07/2016, NT-ICD had been implanted in 36 patients. Nine out of 36 patients (25%) had NT-ICD implantation for primary and 27/36 (75%) for secondary prevention. Underlying diseases included inherited primary electrical arrhythmogenic diseases (n = 26; 72%), cardiomyopathies (n = 8; 22%), and congenital heart defects (n = 2; 6%). The median (interquartile range) age at implantation was 6 (1.9-8.4) years, and the median body weight was 21.7 (11.2-26.8) kg. Three different NT-ICD implantation techniques had been applied over time: (1) abdominal device/subcutaneous shock coil, (2) abdominal device/pleural shock coil, and (3) subcardiac device/pleural shock coil.

RESULTS

During median follow-up of 5.2 (2.7-7.2) years, appropriate ICD discharges were documented in 12 (33.3%) and inappropriate shocks in 4 patients (11.1%). In 12/36 individuals (33.3%), a total of 25 surgical revisions were required due to NT-ICD malfunction. Eighteen out of 25 (72%) surgical revisions were necessary in patients with subcutaneous shock coil/abdominal device position. Surgical revisions (3/25, 12%) were significantly reduced (p < 0.001) after modifying the implantation technique to subcardiac device/pleural shock coil.

CONCLUSIONS

NT-ICD was safe and effective in infants and young children. Appropriate ICD discharges occurred in a considerable number of patients. After modifying the implantation technique, the need for surgical revision could significantly be decreased.

Activation of protein phosphatase 1 by a selective phosphatase disrupting peptide reduces sarcoplasmic reticulum Ca2+ leak in human heart failure

BACKGROUND

Disruption of Ca²⁺ homeostasis is a key pathomechanism in heart failure. CaMKII-dependent hyperphosphorylation of ryanodine receptors in the sarcoplasmic reticulum (SR) increases the arrhythmogenic SR Ca²⁺ leak and depletes SR Ca²⁺ stores. The contribution of conversely acting serine/threonine phosphatases [protein phosphatase 1 (PP1) and 2A (PP2A)] is largely unknown.

METHODS AND RESULTS

Human myocardium from three groups of patients was investigated: (i) healthy controls (non-failing, NF, n = 8), (ii) compensated hypertrophy (Hy, n = 16), and (iii) end-stage heart failure (HF, n = 52). Expression of PP1 was unchanged in Hy but greater in HF compared to NF while its endogenous inhibitor-1 (I-1) was markedly lower expressed in both compared to NF, suggesting increased total PP1 activity. In contrast, PP2A expression was lower in Hy and HF compared to NF. Ca²⁺ homeostasis was severely disturbed in HF compared to Hy signified by a higher SR Ca²⁺ leak, lower systolic Ca²⁺ transients as well as a decreased SR Ca²⁺ load. Inhibition of PP1/PP2A by okadaic acid increased SR Ca²⁺ load and systolic Ca²⁺ transients but severely aggravated diastolic SR Ca²⁺ leak and cellular arrhythmias in Hy. Conversely, selective activation of PP1 by a PP1-disrupting peptide (PDP3) in HF potently reduced SR Ca²⁺ leak as well as cellular arrhythmias and, importantly, did not compromise systolic Ca²⁺ release and SR Ca²⁺ load.

CONCLUSION

This study is the first to functionally investigate the role of PP1/PP2A for Ca²⁺ homeostasis in diseased human myocardium. Our data indicate that a modulation of phosphatase activity potently impacts Ca²⁺ cycling properties. An activation of PP1 counteracts increased kinase activity in heart failure and successfully seals the arrhythmogenic SR Ca²⁺ leak. It may thus represent a promising future antiarrhythmic therapeutic approach.

Risk and Outcome after Simultaneous Carotid Surgery and Cardiac Surgery: Single Centre Experience

OBJECTIVE

Carotid artery stenosis in patients undergoing open-heart surgery may increase risk and deteriorate outcome. The aim of the study was the analysis of risks and outcome after simultaneous carotid and cardiac surgery.

METHODS

We retrospectively reviewed the medical records of 100 consecutive patients who underwent simultaneous carotid surgery and open-heart surgery during a 5-year period (from 2006 to 2010). Seventy patients were male and 30 female; the mean age was 70.9±7.9 years (median: 71.8 years). Seventy-three patients underwent coronary bypass grafting (CABG), 18 patients combined CABG and valve procedures, 7 patients CABG combined with other procedures, and 3 patients isolated valve surgery. More than half of patients had had bilateral carotid artery pathology (n=51) including contralateral carotid artery occlusion in 12 cases.

RESULTS

Carotid artery patch plasty was performed in 71 patients and eversion technique in 29. In 75 cases an intraluminal shunt was used. Thirty-day mortality rate was 7% due to cardiac complications (n=5), metabolic disturbance (n=1), and diffuse cerebral embolism (n=1). There were no carotid surgery-related deaths. Postoperatively, transient cerebral ischemia occurred in one patient and stroke with mild permanent neurological deficit (Rankin level 2) in another patient.

CONCLUSION

Simultaneous carotid artery surgery and open-heart surgery have low risk. The underlying cardiac disease influences outcome.

The effect of a novel turbulence-controlled suction system in the prevention of hemolysis and platelet dysfunction in autologous surgery blood

Background:

Re-transfusion of autologous blood is an important aspect of intraoperative blood management. Hemolysis and platelet dysfunction due to turbulence in the blood suction system strongly impede later usage of suction blood for re-transfusion. The aim of this study was to analyze the effects of a novel surgical-blood suction system with an automatic control setup for minimization of turbulence in the blood flow.

Methods:

We compared the turbulence-controlled suction system (TCSS) with a conventional suction system and untreated control blood in vitro. Blood cell counts, hemolysis levels according to free hemoglobin (fHb) and platelet function were analyzed to determine the integrity of the suction blood.

Results:

In the conventional suction system, we found a strong increase of the fHb levels. In contrast, erythrocyte integrity was almost completely preserved when using the TCSS. We obtained similar results regarding platelet function. The expression of platelet glycoproteins, such as GP IIb/IIIa and P-selectin, native or after stimulation with ADP, were markedly impaired by the conventional system, but not by the TCSS. In addition, platelet aggregometry revealed significant platelet dysfunction in conventional suction blood, but less aggregation impairments were present in blood samples from the TCSS.

Conclusion:

Our findings on an in vitro assessment show major improvements in red blood cell integrity and platelet function of suction blood when using the TCSS compared to a conventional suction system. These results reflect a significant benefit for autologous re-transfusion. We suggest testing the TCSS in surgery for clinical evaluation.

Heart Transplantation in a Toddler with Cardiac Kawasaki Disease

Kawasaki disease is very rare in Western Europe. The disease may involve coronary arteries. A 2-year-old boy diagnosed with Kawasaki disease had had seizure-like symptoms. Further evaluation revealed recurrent myocardial ischemia and myocardial infarction. Due to extraordinary extension of the coronary disease, myocardial revascularization was not feasible and the toddler underwent successful heart transplantation after 97 days on waiting list.

NGAL expression during cardiopulmonary bypass does not predict severity of postoperative acute kidney injury

BACKGROUND

Renal injury is a serious complication after cardiac surgery and therefore, early detection and much more prediction of postoperative kidney injury is desirable. Neutrophil gelatinase-associated lipocalin (NGAL) is a predictive biomarker of acute kidney injury and may increase after cardiopulmonary bypass (CPB). However, time correlation of NGAL expression and severity of renal injury is still unclear. The aim of our study was to investigate CPB-related urine NGAL (uNGAL) secretion in correlation to postoperative renal function.

METHODS

Data of NGAL expression along with clinical data of 81 patients (52 male and 29 female) were included in this study. Mean age of the patients was 66.8 ± 12.8 years. Urine NGAL was measured at seven time points (T₀: baseline; T₁: start CPB, T₂: 40 min on CPB; T₃: 80 min on CPB; T₄: 120 min on CPB; T_p1: 15 min after CPB; T_p2: 4 h after admission to the intensive care unit) and renal function in the postoperative period was classified daily according to Acute Kidney Injury Network (Ronco et al, Int J Artif Organs 30(5): 373-6) criteria (AKIN).

RESULTS

Expression of uNGAL increased at T₄ (120 min on CPB) and post-CPB (T_p1 and T_p2; p < 0.01 vs. baseline) but there was no correlation between uNGAL level and duration of CPB nor between uNGAL expression and occurrence of postoperative kidney injury. The renal function over 10 days after surgery remained normal in 50 patients (AKIN level 0), 18 patients (22%) developed mild and insignificant renal injury (AKIN level 1), eight patients (10%) developed moderate renal failure (AKIN level 2), and five patients (6%) severe kidney failure (AKIN level 3). Twenty-four out of 31 patients developed renal failure within the first 48 h after surgery. However, there was no correlation between uNGAL expression and severity of acute renal failure.

CONCLUSION

Although uNGAL expression increased after CPB, the peak values neither predict acute postoperative kidney injury, nor severity of the injury.

Is there a correlation between late re-exploration after cardiac surgery and removal of epicardial pacemaker wires?

BACKGROUND

Re-exploration for bleeding accounts for increased morbidity and mortality after major cardiac operations. The use of temporary epicardial pacemaker wires is a common procedure at many departments. The removal of these wires postoperatively can potentially lead to a serious bleeding necessitating intervention.

METHODS

From Jan 2011 till Dec 2015 a total of 4244 major cardiac procedures were carried out at our department. We used temporary epicardial pacemaker wires in all cases. We collected all re-explorations for bleeding and pericardial tamponade from our surgical database and then we focused on the late re-explorations, meaning on the 4^th postoperative day and thereafter, trying to identify the removal of the temporary pacemaker wires as the definite cause of bleeding. Patients' records and medication were examined.

RESULTS

Thirty-nine late re-explorations for bleeding, consisting of repeat sternotomies, thoracotomies and subxiphoid pericardial drainages, were gathered. Eight patients had an acute bleeding incidence after removal of the temporary wires (0.18%). In four of these patients, a pericardial drainage was inserted, whereas the remaining patients were re-explorated through a repeat sternotomy. Two patients died of the acute pericardial tamponade, three had a blood transfusion and one had a wound infection. Seven out of eight patients were either on dual antiplatelet therapy or on combination of aspirin and vitamin K antagonist.

CONCLUSIONS

A need for re-exploration due to removal of the temporary pacemaker wires is a very rare complication, which however increases morbidity and mortality. Adjustment of the postoperative anticoagulation therapy at the time of removal of the wires could further minimize or even prevent this serious complication.

Intraoperative Hemofiltration in Adults: Prevention of Hypercirculatory Syndrome?

Hypercirculatory syndrome (HCS) after cardiac surgery may be a sequela of extracorporeal circulation due to hemodilution and release of inflammatory mediators. The aim of this study was to investigate the influence of intraoperative hemofiltration (HF) on the incidence of HCS. A prospective cohort study of 80 patients scheduled for elective coronary bypass was performed. The patients were randomized to two groups: in the conventional (CONV) group 40 patients were treated conventionally and in the HF group 40 patients underwent intraoperative HF. There was no perioperative mortality. The incidence of HCS was comparable in both groups (32% in CONV group versus 40% in HF group; n.s.). Mean cardiac output was higher and systemic vascular resistance lower in CONV group patients than in HF group patients, however these differences did not reach statistical significance. According to this data intraoperative HF does not prevent postoperative HCS induced by cardiopulmonary bypass. Further studies are required to identify the etiology of HCS, and to prevent it occurring after open-heart surgery.

Myocardial histology and outcome after cardiopulmonary bypass of neonatal piglets

Background

Early after neonatal cardiac surgery hemodynamic dysfunction may be evident. However, still is not clear if dysfunction and outcome is related to visible myocardial alterations. The aim of the present study was the histological analysis of myocardial tissue of neonatal piglets after cardiopulmonary bypass (CPB) and cardioplegic arrest.

Methods

Neonatal piglets (younger than 7 days) were connected to CPB for 180 min, including 90 min of cardioplegic heart arrest at 32 °C. After termination of CPB the piglets were observed up to 6 h. During this observational period animals did not receive any inotropic support. Some piglets died within this period and formed the non-survivors group (CPB-NS group) and the remaining animals formed the CPB-6 h group. Myocardial biopsies (stained with H&E) were scored from 0 to 3 regarding histological alterations. Then, the histological data were evaluated and compared to the probes of animals handled comparable to previous piglets but without CPB (non-CPB group; n = 3) and to sibling piglets without specific treatment (control; n = 5).

Results

In the first hours after CPB six piglets out of 10 died (median 3.3 h). The animals of CPB-6 h group (n = 4) were sacrificed at the end of experiments (6 h after CPB). Although the myocardial histological score of CPB-6 h group and CPB-NS group were higher than non-CPB group (2.0 ± 0.8, 1.5 ± 0.9, and 0.8 ± 0.3 respectively), these differences were statistically not significant. But compared to control animals (score 0.3 ± 0.5) the scores of CPB-6 h and CPB-NS groups were significantly higher (p < 0.05). Between the left and the right ventricular tissue there were no significant differences.

Conclusions

Myocardial tissue alterations in newborn piglets are related to the surgical trauma and potentiated by cardiopulmonary bypass and ischemia. However, outcome is not related to the degree of tissue alteration.

Long term biventricular support with Berlin Heart Excor in a Septuagenarian with giant-cell myocarditis

Giant-cell myocarditis (GCM) is known as a rare, rapidly progressive, and frequently fatal myocardial disease in young and middle-aged adults. We report about a 76 year old male patient who underwent implantation with a biventricular Berlin Heart Excor system at the age of 74 due to acute biventricular heart failure caused by giant-cell myocarditis. The implantation was without any surgical problems; however, a difficulty was the immunosuppressive therapy after implantation. Meanwhile the patient is 76 years old and lives with circulatory support for about 3 years without major adverse events. Also, in terms of mobility in old age there are no major limitations. It seems that in even selected elderly patients an implantation of a long term support with the biventricular Berlin Heart Excor is a useful therapeutic option with an acceptable outcome.

Daptomycin and Its Immunomodulatory Effect: Consequences for Antibiotic Treatment of Methicillin-Resistant Staphylococcus aureus Wound Infections after Heart Surgery

Infections by methicillin-resistant Staphylococcus aureus (MRSA) play an increasing role in the postoperative course. Although wound infections after cardiac surgery are rare, the outcome is limited by the prolonged treatment with high mortality. Not only surgical debridement is crucial, but also antibiotic support. Next to vancomycin and linezolid, daptomycin gains increasing importance. Although clinical evidence is limited, daptomycin has immunomodulatory properties, resulting in the suppression of cytokine expression after host immune response stimulation by MRSA. Experimental studies showed an improved efficacy of daptomycin in combination with administration of vitamin E before infecting wounds by MRSA.

Ca 2+ /Calmodulin-Dependent Protein Kinase II and Protein Kinase A Differentially Regulate Sarcoplasmic Reticulum Ca 2+ Leak in Human Cardiac Pathology

Background—

Sarcoplasmic reticulum (SR) Ca 2+ leak through ryanodine receptor type 2 (RyR2) dysfunction is of major pathophysiological relevance in human heart failure (HF); however, mechanisms underlying progressive RyR2 dysregulation from cardiac hypertrophy to HF are still controversial.

Methods and Results—

We investigated healthy control myocardium (n=5) and myocardium from patients with compensated hypertrophy (n=25) and HF (n=32). In hypertrophy, Ca 2+ /calmodulin-dependent protein kinase II (CaMKII) and protein kinase A (PKA) both phosphorylated RyR2 at levels that were not different from healthy myocardium. Accordingly, inhibitors of these kinases reduced the SR Ca 2+ leak. In HF, however, the SR Ca 2+ leak was nearly doubled compared with hypertrophy, which led to reduced systolic Ca 2+ transients, a depletion of SR Ca 2+ storage and elevated diastolic Ca 2+ levels. This was accompanied by a significantly increased CaMKII-dependent phosphorylation of RyR2. In contrast, PKA-dependent RyR2 phosphorylation was not increased in HF and was independent of previous β-blocker treatment. In HF, CaMKII inhibition but not inhibition of PKA yielded a reduction of the SR Ca 2+ leak. Moreover, PKA inhibition further reduced SR Ca 2+ load and systolic Ca 2+ transients.

Conclusions—

In human hypertrophy, both CaMKII and PKA functionally regulate RyR2 and may induce SR Ca 2+ leak. In the transition from hypertrophy to HF, the diastolic Ca 2+ leak increases and disturbed Ca 2+ cycling occurs. This is associated with an increase in CaMKII- but not PKA-dependent RyR2 phosphorylation. CaMKII inhibition may thus reflect a promising therapeutic target for the treatment of arrhythmias and contractile dysfunction.

Low-output is not the cause of death of neonatal piglets early after cardiopulmonary bypass

The mortality rate of neonatal piglets after heart surgery is high. Searching for a possible explanation for the death of neonatal piglets early after cardiopulmonary bypass, we analyzed hemodynamic parameters regarding survival and non-survival. Initially, 10 neonatal piglets (younger than 7 days) were connected to cardiopulmonary bypass (CPB). The mean body weight was 2.98 ± 0.44 kg. Exposure of the heart was performed through a median sternotomy. After connection to the CPB, the piglets were cooled to 32°C core temperature before the ascending aorta was cross-clamped and the heart arrested (90 min). Thereafter, piglets were re-warmed to 37°C and separated from CPB. During follow-up, the piglets did not receive inotropic support or vasopressors. Piglets who survived at least 2 h after termination of CPB were included in the study for further data analysis (n = 9). Five piglets died 2.5 to 4.0 h (median: 3.5 h) after CPB; these piglets formed the non-survivors group. Four animals survived the complete follow-up of 6 h after CPB and formed the survivors group. Regarding contractility (dP/dt(max) , dP/dt(max) /P, and wall thickening) there were not statistically significant differences between the groups. Non-survivors showed prolonged decrease of mean arterial pressure of more than 20% of baseline values, corresponding with a value of below 30 mm Hg. In conclusion, the death of neonatal piglets early after cardiopulmonary bypass was not determined by low output.

The effect of cardiopulmonary bypass and hypothermic circulatory arrest on hepatic histology in newborn animals: an experimental study

Still little is known about the effect of cardiac surgery on neonatal hepatic tissue. We examined the effect of cardiopulmonary bypass (CPB) and the effect of deep hypothermic circulatory arrest (DHCA) on neonatal hepatic tissue. Liver biopsies of neonatal piglets were taken after CPB (n = 4), after DHCA (n = 5), and after surgery without CPB (non-CPB; n = 3). Additionally, findings were compared to those of control piglets (n = 9). The liver specimens were fixed, stained with hematoxylin and eosin, and scored regarding inflammatory reaction, hepatocellular edema, and apoptosis. Inflammation score of treated groups was higher than in control; CPB 2.5 ± 0.5, DHCA 1.6 ± 0.4, non-CPB 1.2 ± 0.6, control 0.4 ± 0.3 (P < 0.001 CPB and DHCA vs. control; P < 0.05 non-CPB vs. control). Hepatic cell edema was more evident after DHCA (score 2.0 ± 0.4 vs. 0.2 ± 0.3 in control and 0.6 ± 0.5 after CPB; P < 0.001 and P < 0.05, respectively). The highest apoptotic cell count was in the non-CPB group (22.3 ± 6.3 vs. 11.4 ± 3.6 in control and 8.9 ± 5.4 after CPB; P < 0.05). The present study showed that (i) surgical trauma induces hepatic cell apoptosis; (ii) CPB increases hepatic inflammatory reaction; and (iii) DHCA amplifies hepatic cell edema.

A new device for intraoperative renal blood flow measurement during open-heart surgery: an experimental study and the clinical pilot study

Renal blood flow (RBF) may vary during cardiopulmonary bypass and low flow may cause insufficient blood supply of the kidney triggering renal failure postoperatively. Still, a valid intraoperative method of continuous RBF measurement is not available. A new catheter combining thermodilution and intravascular Doppler was developed, first calibrated in an in vitro model, and the catheter specific constant was determined. Then, application of the device was evaluated in a pilot study in an adult cardiovascular population. The data of the clinical pilot study revealed high correlation between the flow velocities detected by intravascular Doppler and the RBF measured by thermodilution (Pearson's correlation range: 0.78 to 0.97). In conclusion, the RBF can be measured excellently in real time using the new catheter, even under cardiopulmonary bypass.

A clinical student exchange program organized by cardiothoracic department: feedback of participants

Background

The development of a student exchange program was an essential part of the cooperation between the Medical Schools of the University of Goettingen (Germany) and the University of Thrace in Alexandroupolis (Greece). The student exchange program started in 2008 and was performed once a year. The experiences of this program and the feedback of participants are presented.

Methods

Although organized by the Dept. of Thoracic, Cardiac, and Vascular Surgery, the approach of the program was multidisciplinary. Participants also attended Continuous Medical Education activities primary addressed to physicians. At the end of the program, the participants evaluated the program anonymously. The educational units were rated via a 4-grade system. Additionally, it was possible to comment both positive and negative aspects of the program.

Results

Twenty-nine educational units were evaluated. The practical teaching units yielded a better result than the classical teaching units (93% of practical units were evaluated as “very good” vs. 74% of lectures/seminars). The Continuous Medical Education activities were evaluated less favorable (only 61% were evaluated as “very good”).

Conclusions

The student exchange program enhanced effective teaching and learning. Courses supporting practical medical skills were extremely positive evaluated. Continuous Medical Education activities are not suitable for students and therefore, we do not include such an event anymore. Additionally, the program created an excellent forum for contact and communication between the students of the two universities.

Carotid Doppler flow after cardiopulmonary bypass and mild hypothermia in neonatal piglets

Although the mechanisms of neurological disorders after cardiac surgery in neonates are still not fully understood, alterations in blood flow after cardiopulmonary bypass (CPB) may lead to cerebral injury. The aim of the study was the analysis of flow changes in the carotid artery of neonatal piglets after CPB. Ten neonatal piglets (younger than 7 days) were connected to the CPB and further management underwent three steps: (i) cooling to 32°C core temperature within 30 min; (ii) cardiac arrest under cardioplegic myocardial protection for 90 min; and (iii) rewarming to 37°C after cross-clamp release (60 min of reperfusion). In summary, piglets were separated from CPB after a total duration time of 180 min. The blood flow was measured in the left carotid artery by an ultrasonic flow probe before CPB (baseline), immediately after CPB, 30 min, and 60 min after CPB. Additionally, the pulsatility index and the resistance index were calculated and compared. Finally, the relation of the carotid artery flow data with the corresponding pressure data at each time point was compared. After termination of CPB, the carotid artery mean flow was reduced from 28.34 ± 13.79 mL/min at baseline to 20.91 ± 10.61 mL/min and remained reduced 30 and 60 min after CPB termination (19.71 ± 11.11 and 17.64 ± 15.31 mL/min, respectively). Both the pulsatility and the resistance index were reduced immediately after CPB termination and increased thereafter. Nevertheless, values did not reach statistical significance. In conclusion, the carotid Doppler flow immediately after CPB and mild hypothermia in neonatal piglets was lower than before CPB due to reduced vascular resistance. Additionally, the pressure-flow relation revealed that immediately after CPB, a higher pressure is required to obtain adequate flow.

Aortic surgery after previous procedure of congenital aortic stenosis

Irrespective of previous procedure in congenital aortic stenosis, aortic surgery later in life may be indicated. The aim of the present study was the analysis of indications, risks, and outcomes of aortic surgery after previous aortic valve procedure. The data of patients who underwent aortic surgery after previous treatment of congenital aortic stenosis in a 10-year period (from 2000 to 2009) were retrospectively analyzed. Thirty-two patients (23 male and 9 female) underwent redo aortic surgery. The mean age at surgery was 13.5 ± 11.3 years. Seventeen patients had undergone initial aortic balloon valvuloplasty (BVP) and 15 patients open commissurotomy (COM). Nine cases had undergone the primary procedure at neonatal age and two patients had undergone cardiac surgery before the initial aortic valve procedure. Seven of the patients with previous COM (43.8%) had undergone concomitant surgery along with initial commissurotomy. A reintervention within the first year after the primary procedure was performed in seven patients (seven after BVP and none after COM; P < 0.05). The interval between the last intervention and the first redo aortic surgery was 7.5 ± 9.5 years (3.1 ± 3.5 years after BVP vs. 12.5 ± 11.7 years after COM; P < 0.05). A second redo surgery was performed in nine patients (four after initial BVP and five after COM). Congenital aortic stenosis is very often presented in combination with additional pathologies. These concomitant diseases along with the underlying disease give the indication for reoperation. Reinterventions are more often indicated after primary BVP. Long follow-up in specialized centers is mandatory.

Acute thrombosis of mechanical bi-leaflet aortic valve prosthesis

Thrombosis of mechanical aortic valve prosthesis is a rare but life-threatening complication. In most reported cases, inadequate anticoagulation or cessation of anticoagulation is the cause of prosthesis thrombosis. The case of a 70-year-old male patient hospitalized for severe dyspnoea is presented. Although the patient was under continuous anticoagulation, thrombosis of the 16 years previously implanted mechanical 31-sized aortic valve prosthesis was diagnosed. Emergency surgery was performed and postoperative course was uneventful. Patients with large size prostheses should have closer anticoagulation monitoring, even after many years of event-free postimplant course.

Midterm results after arterial switch operation for transposition of the great arteries: a single centre experience

Background

The arterial switch operation (ASO) has become the surgical approach of choice for d-transposition of the great arteries (d-TGA). There is, however an increased incidence of midterm and longterm adverse sequelae in some survivors. In order to evaluate operative risk and midterm outcome in this population, we reviewed patients who underwent ASO for TGA at our centre.

Methods

In this retrospective study 52 consecutive patients with TGA who underwent ASO between 04/1991 and 12/1999 were included. To analyze the predictors for mortality and adverse events (coronary stenoses, distortion of the pulmonary arteries, dilatation of the neoaortic root, and aortic regurgitation), a multivariate analysis was performed. The follow-up time was ranged from 1–10 years (mean 5 years, cumulative 260 patient-years).

Results

All over mortality rate was 15.4% and was only observed in the early postoperative period till 1994. The predictors for poor operative survival were low APGAR-score, older age at surgery, and necessity of associated surgical procedures. Late re-operations were necessary in 6 patients (13.6%) and included a pulmonary artery patch enlargement due to supravalvular stenosis (n = 3), coronary revascularisation due to coronary stenosis in a coronary anatomy type E, aortic valve replacement due to neoaortic valve regurgitation (n = 2), and patch-plasty of a pulmonary vein due to obstruction (n = 1). The dilatation of neoaortic root was not observed in the follow up.

Conclusions

ASO remains the procedure of choice for TGA with acceptable early and late outcome in terms of overall survival and freedom of reoperation. Although ASO is often complex and may be associated with morbidity, most patients survived without major complications even in a small centre.

Double inferior vena cava

Venous anomalies involving the inferior vena cava are very rare. The case of a 74-year-old man with coronary artery disease is presented. Interestingly, a double inferior vena cava was incidentally discovered during coronary artery bypass grafting. Persistence of the left hepatic segment vein appeared as a left inferior vena cava-a very rare condition.

Cardiopulmonary bypass and its direct effects on neonatal piglet kidney morphology

Renal failure after open heart surgery is a serious complication even in the pediatric population. The aim of the present study was to analyze morphological changes after cardiopulmonary bypass (CPB) surgery in a neonatal piglet model. The kidneys of newborn piglets sacrificed 6 h after CPB were examined (CPB; n = 4) regarding tubular dilatation, vacuole formation, leukocytic infiltration, epithelial destruction, and interstitial edema. Thereafter, the findings were compared with the morphology of normal (untreated) neonatal piglet kidneys (control; n = 4). All changes but the interstitial edema were statistically significant if compared with the normal renal tissue: tubular dilatation (CPB vs. control P < 0.05), vacuole formation (CPB vs. control P < .05), leukocytic infiltration (CPB vs. control P < 0.05), and epithelial destruction (CPB vs. control P < 0.001). In conclusion, CPB induces significant changes in the morphology of the neonatal piglet kidneys.

Treatment of gram-positive deep sternal wound infections in cardiac surgery--experiences with daptomycin

The reported incidence of deep sternal wound infection (DSWI) after cardiac surgery is 0.4-5% with Staphylococcus aureus being the most common pathogen isolated from infected wound sternotomies and bacteraemic blood cultures. This infection is associated with a higher morbidity and mortality than other known aetiologies. Little is reported about the optimal antibiotic management. The aim of the study is to quantify the application of daptomycin treatment of DSWI due to gram-positive organisms post cardiac surgery. We performed an observational analysis in 23 cases of post sternotomy DSWI with gram-positive organisms February 2009 and September 2010. When the wound appeared viable and the microbiological cultures were negative, the technique of chest closure was individualised to the patient. The incidence of DSWI was 1.46%. The mean dose of daptomycin application was 4.4 ± 0.9 mg/kg/d and the average duration of the daptomycin application was 14.47 ± 7.33 days. In 89% of the patients VAC therapy was used. The duration from daptomycin application to sternal closure was 18 ± 13.9 days. The parameters of infection including, fibrinogen (p = 0.03), white blood cell count (p = 0.001) and C-reactive protein (p = 0.0001) were significantly reduced after daptomycin application. We had no mortality and wound healing was successfully achieved in all patients. Treatment of DSWI due to gram-positive organisms with a daptomycin-containing antibiotic regimen is safe, effective and promotes immediate improvement of local wound conditions.Based on these observations, daptomycin may offer a new treatment option for expediting surgical management of DSWI after cardiac surgery.

Myocardial contractility and relaxation after deep hypothermic circulatory arrest in a neonatal piglet model

Cooling before circulatory arrest or ischemic arrest has been reported to influence myocardial performance in isolated neonatal hearts. The aim of the present study was to analyze indices of myocardial contractility and relaxation in an in vivo neonatal model after deep hypothermic circulatory arrest (DHCA). DHCA (18°C; DHCA group; n = 8) or mild hypothermic cardiopulmonary bypass ([MH-CPB] 32°C; MH-CPB group; n = 10) was applied in newborn piglets. After reperfusion (60 and 120 min), left ventricular dP/dt(max) increased in DHCA and MH-CPB, while-dP/dt(max) decreased slightly in DHCA and increased in MH-CPB. Nevertheless, the differences between the two groups did not reach statistical significance. In conclusion, left ventricular contractility remained stable after reperfusion following DHCA, to some degree at the expense of the diastolic function.

Extracorporeal circulation for rewarming in drowning and near-drowning pediatric patients

Drowning and near-drowning is often associated with severe hypothermia requiring active core rewarming.We performed rewarming by cardiopulmonary bypass(CPB). Between 1987 and 2007, 13 children (9 boys and 4 girls) with accidental hypothermia were rewarmed by extracorporeal circulation (ECC) in our institution. The average age of the patients was 3.2 years. Resuscitation was started immediately upon the arrival of the rescue team and was continuously performed during the transportation.All patients were intubated and ventilated. Core temperature at admission ranged from 20 to 29°C (mean 25.3°C). Connection to the CPB was performed by thoracic (9 patients) or femoral/iliac means (4 patients). Restoration of circulation was achieved in 11 patients (84.6%). After CPB termination two patients needed an extracorporeal membrane oxygenation system due to severe pulmonary edema.Five patients were discharged from hospital after prolonged hospital stay. During follow-up, two patients died(10 and 15 months, respectively) of pulmonary complications and one patient was lost to follow-up. The two remaining survivors were without neurological deficit.Modes of rewarming, age, sex, rectal temperature, and serum electrolytes did not influence mortality. In conclusion,drowning and near-drowning with severe hypothermia remains a challenging emergency. Rewarming by ECC provides efficient rewarming and full circulatory support.Although nearly half of the children may survive after rewarming by ECC, long-term outcome is limited by pulmonary and neurological complications.