Effects of doxorubicin and ibrutinib on atrial arrhythmogenity: ex-vivo assessment in human myocardium

Introduction

The cytostatic drugs doxorubicin (Dox) and ibrutinib (Ibr) are established in the treatment of various tumor diseases. In (pre-) clinical studies, both chemotherapeutic agents showed cardiotoxic side effects, including atrial fibrillation [1]. In this context, patients with limited cardiac performance or diabetes might be particularly vulnerable, as these pre-existing conditions represent independent risk factors for cardiac complications [2].

Objectives

The dose-dependency of acute pro-arrhythmogenic effects of Dox and Ibr on the contractile activity of human atrial muscle tissue was investigated.

Patients and methods

Atrial samples were taken intraoperatively during cardiac procedures. Functional muscle strips were prepared from the cardiac trabeculae, followed by incubation with different concentrations of Dox or Ibr for 30 minutes. Subsequently, functional measurements were performed. Isometric contraction force and arrhythmogenic occurrences were recorded. The samples were consecutively exposed to external stressors during measurement (Fig. 1).

We evaluated the overall occurrence of arrhythmogenic contractions and during which phase of the protocol they occurred. The latter was expressed as degree of arrhythmogenesis (Fig. 1).

Following the functional measurements, the muscle strips were conserved at −80°C.

Results

We isolated 127 muscle strips from 29 patients. Highest rates of overall arrhythmic contractions were observed at 10μM Dox and 0.5μM Ibr (77.8 & 100% vs. 58.4% (control)). Mean degree of arrhythmogenesis increased from 1.63 (control) to 2.17 (10μM Dox) and 3.11 (0.5μM Ibr).

Analyzing our data according to the included individuals, treatment with Dox and Ibr enhanced the degree of arrhythmogenesis in the majority of patients. (Fig. 2)

Conclusion

Our protocol is suitable for investigating drug related acute pro-arrhythmogenic effects on human atrial myocardium. Treatment of isolated atrial myocardium with Dox and Ibr enhanced its susceptibility to arrhythmogenic occurrences. Optimal pro-arrhythmogenic conditions were observed at 10μM Dox and 0.5μM Ibr. The treated samples showed higher overall rates of arrhythmogenic contractions and the arrhythmogenic activity occurred earlier within our protocol.

Outlook

We will correlate the experimentally obtained data with clinical patient data, such as LVEF, BMI and diabetic status. The conserved muscle strips will be analyzed using standardized assays comparing post-translational modification (e.g. phosphorylation and oxidation) of key regulators of excitation contraction coupling (e.g. PKA, CaMKII, Ca2+ channels).

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): DZHK (German Centre for Cardiovascular Research), partner site Berlin

Insight into the incidence of acute aortic dissection in the German region of Berlin and Brandenburg

BACKGROUND

Stanford acute type A aortic dissection (ATAAD) is a potentially lethal condition. Epidemiology studies show a statistical incidence in Europe of approximately 2-16 cases/100,000 inhabitants/year. In Germany, the estimated incidence (here subsumed under "thoracic aortic dissection" with 4.63 cases/100,000 inhabitants/year) is mainly extracted from medical death certificates by the German Federal Statistical Office. The prehospital incidence of ATAAD deaths is largely unknown. Since patients often die in the pre-hospital setting, the incidence of ATAAD is therefore likely to be higher than current estimates.

MATERIAL AND METHODS

For the period from 2010 to 2014, we retrospectively analyzed all in-hospital ATAAD data from two of the largest cardiac surgical centers that treat ATAAD in the Berlin-Brandenburg region. In addition, autopsy reports of all forensic medicine institutes and of one large pathological provider in the region were analyzed to identify additional non-hospitalized ATAAD patients. Based on these findings, the regional incidence of ATAAD was calculated.

RESULTS

In addition to in-hospital ATAAD patients (n=405), we identified additional 145 lethal ATAAD cases among 14,201 autopsy reports. The total of 550 ATAAD cases led to an estimated incidence of 11.9 cases/100,000 inhabitants/year for the whole Berlin-Brandenburg region. Arterial hypertension, pre-existing aortic dilatation, and hereditary connective tissue disorder were found in, respectively, 62.7%, 10%, and 1.8% of patients.

CONCLUSION

ATAAD is more frequent than previously reported. Our results show that when patients who die outside of cardiac surgery centers are included, the incidence of ATAAD significantly exceeds the rate reported by the Federal Statistical Office.

Feasibility and influence of hTEE monitoring on postoperative management in cardiac surgery patients

Monoplane hemodynamic TEE (hTEE) monitoring (ImaCor(®) ClariTEE(®)) might be a useful alternative to continuously evaluate cardiovascular function and we aimed to investigate the feasibility and influence of hTEE monitoring on postoperative management in cardiac surgery patients. After IRB approval we reviewed the electronic data of cardiac surgery patients admitted to our intensive care between 01/01/2012 and 30/06/2013 in a case-controlled matched-pairs design. Patients were eligible for the study when they presented a sustained hemodynamic instability postoperatively with the clinical need of an extended hemodynamic monitoring: (a) hTEE (hTEE group, n = 18), or (b) transpulmonary thermodilution (control group, n = 18). hTEE was performed by ICU residents after receiving an approximately 6-h hTEE training session. For hTEE guided hemodynamic optimization an institutional algorithm was used. The hTEE probe was blindly inserted at the first attempt in all patients and image quality was at least judged to be adequate. The frequency of hemodynamic examinations was higher (ten complete hTEE examinations every 2.6 h) in contrast to the control group (one examination every 8 h). hTEE findings, including five unexpected right heart failure and one pericardial tamponade, led to a change of current therapy in 89% of patients. The cumulative dose of epinephrine was significantly reduced (p = 0.034) and levosimendan administration was significantly increased (p = 0.047) in the hTEE group. hTEE was non-inferior to the control group in guiding norepinephrine treatment (p = 0.038). hTEE monitoring performed by ICU residents was feasible and beneficially influenced the postoperative management of cardiac surgery patients.

An electronic tool for visual feedback to monitor the adherence to quality indicators in intensive care medicine

Evidence-based medicine is often inadequately implemented in intensive care units (ICU); the aim of this study was to improve its implementation via a technical feedback system, using key performance indicators (KPI). The study evaluated 205 patients treated in a cardiac surgical ICU over a 6-month period (3 months before and 3 months after implementation of the feedback system). KPI adherence rates for sedation, delirium and pain monitoring, and completion of a weaning protocol before and after the implementation of the feedback system, were compared. Adherence rates for pain and delirium monitoring, and implementation of the weaning protocol, were significantly increased by the intervention. Adherence to KPIs for sedation, which were high at baseline, could not be further improved. Daily display of KPI implementation had a positive effect on adherence to standard operating procedures. Adherence to guidelines may be improved by using this feedback system as part of the clinical routine.

Single Center Experience with Short-term Circulatory Support: A Comparison of Demography, Indication and Clinical Outcome over the past Decade

Objective

Aim of the study was to analyze changes over a ten years observation period regarding demography, indication for support and clinical outcome in patients treated with short-term mechanical circulatory support (MCS) for cardiogenic failure.

Methods

39 patients treated with MCS between 2006–2008 (2008 group) were analyzed, assessing demography, complication rates and survival. Results were compared with 36 consecutive patients that had received centrifugal MCS between 1996–1998 (1998 group) at our institution.

Results

Mean age was 59.9 ± 12.9 (1998 group) and 60.9 ± 13.9 years ( P = 0.74). Mean logEuroScores rose from 12.0% ± 14.6% (1998 group) to 26.9% ± 20.5% (2008 group); P < 0.001. Postcardiotomy low output syndrome was the main cause for MCS. However the percentage of patients in cardiogenic shock prior to surgery increased from 19.4% (1998 group) to 33.3% (2008 group); P = 0.17. Complexity and urgency of the primary surgical procedure increased significantly. 16.7% (1998 group) vs. 41.0% (2008 group); P = 0.02 of interventions were classified “salvage/emergent”. Mean duration of support was 2.9 ± 1.9 days (1998 group) and 3.8 ± 3.1 days (2008 group); P = 0.14. Significantly more biventricular support was implemented in the 2008 group (23.1% vs. 5.6% in the 1998 group); P = 0.03. The incidence of complications, including device failure, thromboembolism and infection remained the same in both groups. 63.9% (1998 group) and 61.5% (2008 group) of the patients were successfully weaned from the device ( P = 0.83), 12% (1998 group) and 3% (2008 group) of the VAD patients were bridged to long-term VAD ( P = 0.12). Overall 30-day survival rates were similar (22.2% 1998 group vs. 28.2%; 2008 group); P = 0.55, however, survival rate in BVAD supported patients improved significantly.

Conclusion

These data demonstrate the beneficial effect of MCS to salvage patients with cardiac failure. Taking into consideration that the severity of illness, the complexity and urgency of the primary surgical procedure have steadily increased a comparable improvement in MCS outcome over the past decade was observed. Nevertheless, in-hospital mortality and VAD related complication rates such as bleeding remain high.

Recombinant activated factor VII for treatment of refractory hemorrhage after surgery for acute aortic dissection

Despite appropriate treatment, surgery for aortic dissection is frequently associated with bleeding problems. In these series we report on the employment of recombinant activated factor VII (rFVIIa) for refractory hemorrhage after emergency surgery for acute type A aortic dissection, used to face the problems of postoperative blood loss and transfusion requirements. Despite the good results of the therapy, a patient presented with thrombosis of the left cavernous sinus. Although a risk of thromboembolic complications has to be considered, rFVIIa is a reasonable rescue option in life-threatening hemorrhage and enlarges our hemostatic armamentarium in surgery for acute aortic dissection.

[Bleeding after cardiac surgery: the role of recombinant factor VIIa]

Cardiac surgery carries a remarkable risk of blood loss requiring transfusion of blood products. Moreover, severe bleeding necessitating reoperation occurs in 3-5% of patients according to international studies. These patients face a significantly higher morbidity and mortality. This underscores the need for a safe and effective haemostatic therapy, which may significantly improve the outcome. Recombinant activated factor VII is approved for haemophiliacs with inhibitors and patients with thrombasthenia Glanzmann and factor VII deficiency. In the proceeding years a series of articles has been published reporting the successful and safe therapy of refractory bleeding after cardiac surgery. This review focuses at presenting the pathophysiological alterations of the haemostatic system related to the cardiopulmonary bypass. These alterations are thought to explain the high risk of bleeding after cardiopulmonary bypass. Furthermore, the use of rFVIIa in paediatric and adult cardiac surgery is reviewed and critically discussed.

Bleeding after cardiac surgery

Cardiac surgery carries the risk of significant blood loss requiring the transfusion of blood products. In addition to such blood loss, international studies have shown that severe bleeding necessitating re-operation occurs in 3–5% of patients. Morbidity and mortality are significantly increased, so effective and safe haemostatic measures will decisively improve outcome of patients.

Recombinant activated factor VII (rFVIIa) has been approved for the treatment of patients with inhibitor haemophilia, as well as with Glanzmann’s thrombasthenia and factor VII deficiency. Many publications have appeared in the last few years which report the successful and reliable use of rFVIIa for the treatment of refractory bleeding after cardiac surgery. This review presents the pathophysiological changes in the coagulation system which occur when a heart-lung machine is used and which have been blamed for an increased risk of bleeding in patients who have undergone cardiac surgery. Published experience with rFVIIa in paediatric and adult cardiac surgery is presented and discussed critically with regard to the efficacy and safety of its use.

Blutungen nach herzchirurgischen Operationen

Herzchirurgische Operationen sind mit dem Risiko verbunden, einen relevanten Blutverlust zu erleiden und eine Transfusion von Blutprodukten zu erhalten. Neben dem Blutverlust treten internationalen Studien zufolge schwere Blutungen, die eine Reoperation zur Blutstillung erfordern, bei 3-5% der Patienten auf. Die Morbidität und Mortalität ist signifikant erhöht, so dass eine effektive und sichere hämostatische Therapie die Prognose entscheidend verbessern kann.

Rekombinanter aktivierter Faktor VII ist für die Therapie von Patienten mit Hemmkörper-Hämophilie sowie Thrombasthenie Glanzmann und Faktor-VII-Mangel zugelassen. In den vergangenen Jahren häufen sich die Publikationen, die über eine erfolgreiche und sichere Stillung von Blutungen nach herzchirurgischen Operationen berichten, die einer konventionellen Therapie gegenüber refraktär waren. Dieses Review stellt die pathophysiologischen Veränderungen des Gerinnungssystems, die der Anschluss an die Herz- Lungen-Maschine induziert und die für die Erklärung des erhöhten Blutungsrisikos herzchirurgischer Patienten herangezogen werden, dar. Die publizierten Erfahrungen mit rFVIIa in der Kinder- und Erwachsenen-Herzchirurgie werden dargestellt und hinsichtlich der Effektivität und Sicherheit kritisch diskutiert.

Aspirin and Clopidogrel Taken Until 2 Days Prior to Coronary Artery Bypass Graft Surgery Is Associated with Increased Postoperative Drainage Loss

OBJECTIVE

Platelet aggregation inhibitors, such as aspirin and clopidogrel, are associated with increased bleeding in patients undergoing cardiac surgery with cardiopulmonary bypass. We investigated the impact of time between the last intake of aspirin and clopidogrel before CABG surgery and drainage loss, transfusion requirements and rate of reoperation.

PATIENTS AND METHODS

The records of patients who had coronary artery bypass graft surgery (CABG) were reviewed for intake of aspirin and clopidogrel within 7 days prior to surgery. Drainage loss, transfusion requirements and rate of reoperation for bleeding within 5 days after the operation, were recorded.

RESULTS

Out of 261 analysed patients, 225 patients (86.2 %) had no anti-platelet medication and 36 patients (13.8 %) were on aspirin and clopidogrel. Aspirin and clopidogrel, taken all until 2 days prior to operation, were associated with a significantly higher postoperative blood loss (1840 mL [1230 - 3710] vs. 280 mL [185 - 765], p = 0.005 for one day and 850 mL [345 - 1725] vs. 277 mL [165 - 778], p = 0.026, for 2 days prior to surgery). The trend showed that patients in the study group received more platelet concentrates (PC: 5.3 % vs. 13.9 %, p = 0.067). The rate of reoperation for bleeding was not different ( p = 0.25).

CONCLUSION

Aspirin and clopidogrel up to 2 days prior to CABG were associated with a significantly higher postoperative drainage loss.

Impact of Implantation Technique on Hemodynamic Results of the Pericarbon Freedom Stentless™ Valve

BACKGROUND

The Pericarbon Freedom stentless valve has shown excellent hemodynamic results in the midterm course. However, there is no information as to whether a continuous or interrupted suture technique at the inflow site has an impact on postoperative hemodynamics.

METHODS

139 patients were enrolled in a non-randomized, prospective matched trial. An interrupted suture line technique was used in 68 patients and a continuous suture line technique was used in 71 at the inflow site. Isolated valve replacement was performed in 70.4% of the continuous and 67.6% of the interrupted suture group. Pre- and postoperative hemodynamics and one-year follow-up were obtained by echocardiography and expressed as mean and peak gradients and grade of regurgitation.

RESULTS

No significant difference between continuous and interrupted suture techniques were noted with respect to mean (11.8 +/- 6.3 vs. 12.5 +/- 6.2 mm Hg, p = 0.251) and peak gradients (21.0 +/- 9.6 vs. 22.0 +/- 10.9 mm Hg, p = 0.292) as well as to the degree of regurgitation. Bypass and cross-clamping times decreased by 22.4 and 20.6 minutes, respectively, with the use of the continuous suture technique. One year follow-up showed a further, significant decrease of mean and peak gradients.

CONCLUSIONS

The Pericarbon Freedom stentless valve appears to offer excellent postoperative performance. The suture line technique at the inflow site does not result in any hemodynamic differences.

Clopidogrel-Related Refractory Bleeding after Coronary Artery Bypass Graft Surgery: A Rationale for the Use of Coagulation Factor Concentrates?

Clopidogrel, an irreversible ADP-receptor antagonist, inhibits platelet aggregation mediated by reduced activation of glycoprotein receptor IIb/IIIa. Clopidogrel in combination with aspirin has been shown to be superior to aspirin alone for treating unstable angina, but clopidogrel recipients have shown increases in blood loss, transfusion requirements, and rate of reoperation after cardiac surgery. We describe a patient who had taken clopidogrel 75 mg daily until the day prior to coronary artery bypass graft surgery. Severe postoperative bleeding developed and was refractory to conventional hemostatic therapy consisting of 19 units of packed red blood cell concentrates, 16 of fresh frozen plasma, 8 of platelet apheresis concentrates plus high-dose treatment with aprotinin (500.000 kallikrein-inhibiting units/h) and administration of 0.3 3g/kg 1-deamino-8-D-arginine vasopressin (DDAVP). Two reoperations were performed, but surgical hemostasis was not achieved, so 100 3g/kg recombinant activated factor VII was applied to generate sufficient thrombin to stop the bleeding. This treatment approach reduced the bleeding. Then, to promote clot formation and firmness, 2 g of fibrinogen and 1250 IU of factor XIII were administered, and the bleeding finally stopped. No further transfusions were required, and the patient was discharged from the hospital on day 10 after the operation. This case suggests that in clopidogrel-related bleeding refractory to conventional hemostatic therapy, hemostasis may be achieved by a stepwise administration of coagulation factor concentrates.

Sarcoma associated with silver coated mechanical heart valve prosthesis

Sarcomas can develop in association with foreign material (eg, from Dacron vascular prostheses). We report on a left atrial rhabdomyosarcoma that developed within 1 year of mitral valve replacement by a Silzone-coated St. Jude Medical mechanical heart valve. Tumor resection and redo valve replacement were done. Six months later the patient was alive, but an echocardiogram showed tumor recurrence. Although this is a single case, an association between heart valve prostheses and malignant tumors should be considered.

Emergency coronary artery bypass grafting: does excessive preoperative anticoagulation increase bleeding complications and transfusion requirements?

Patients requiring urgent surgical revascularization due to unstable coronary artery disease are usually pretreated with multiple antithrombotic drugs. The perioperative risks of this type of treatment were investigated in 123 patients who underwent emergency coronary artery bypass grafting (CABG) at our institution.Eighty-two patients (group A) received heparin and acetylsalicylic acid solely and 41 patients (group B) received additionally ADP-receptor antagonists (82.9%), glycoprotein IIb/IIIa inhibitors (12.2%) or thrombolysis (14.6%) preoperatively. Both groups were similar regarding demographic data and overall clinical status. Preoperative coagulation parameters and intraoperative characteristics were comparable. Blood loss via chest tubes was not significantly different between groups. Transfusion of red blood cells and fresh frozen plasma were slightly, but not significantly increased in group B. Transfusion of pooled platelets was low in general and similar in both groups. Re-exploration rate, medium intensive care unit and hospital stay as well as perioperative mortality were comparable.Excessive antithrombotic pretreatment seems to bear no additional risk in emergency CABG and may be beneficial in this setting.

Stunned myocardium after off-pump coronary artery bypass grafting

Off-pump coronary artery bypass grafting is increasingly performed. Because these procedures are associated with temporary myocardial ischemia, there is a risk of ischemia-related complications. We report two cases of myocardial stunning after off-pump coronary artery bypass grafting using the Octopus tissue stabilizer. On the basis of our experiences, means to prevent stunning are discussed.

Anticoagulation in extracorporeal circulation using recombinant hirudin: a case report

Heparin-induced thrombocytopenia (HIT) is a severe complication following the application of heparin; antibodies against complexes of heparin and PDF4 initiate activation of platelets. This may lead to massive thrombembolism, which is associated with a slight and transient drop of platelets in HIT I or a drop below 50% after approximately 5 days in HIT II. Further administration of heparin has to be strictly avoided in these patients. Immunologic evidence for HIT can easily be obtained by the heparin-induced platelet aggregation assay. If anticoagulation is necessary, different, alternative drugs are available. Recombinant hirudin (r-hirudin) is a well-established drug for safe anticoagulation. Monitoring is possible by estimating the plasma level of r-hirudin from the ecarin-clotting time. We report a case of a patient with prosthetic aortic valve endocarditis and HIT II who suffered from massive postoperative bleeding requiring massive substitution of blood components and coagulants caused by free circulating r-hirudin due to the use of a hemofilter.

Pumpless arteriovenous extracorporeal lung assist: what is its role?

Extracorporeal lung assist (ECLA) is an established treatment of severe pulmonary failure. Since extracorporeal perfusion is applied in a long-term fashion in this setting, the negative impact on blood compounds is of tremendous importance. Pumpless arteriovenous ECLA (av-ECLA) is an alternatively introduced technique that focuses on reduced blood traumatization. However, due to determining technical and physiological aspects, its clinical application is limited to a highly selected group of patients. Membrane oxygenators with minimal pressure gradients, as well as stable patients' haemodynamics providing a sufficient cardiac output, are the most important prerequisites. With respect to recent reports, characteristic features of av-ECLA, with special emphasis on its physiological background, are reviewed. Accordingly, reasonable indications for its beneficial use are discussed. It is concluded that av-ECLA is a feasible technique when its limitations are accepted. For adequate clinical use, more data concerning indications, as well as time- and technique-related directions are required.

Severe heart valve calcification in a young patient with Werner syndrome

Werner syndrome is a rare autosomal recessive disorder characterized by the appearance of premature aging. We report on severe aortic and mitral valve calcification in an 18-year-old girl, necessitating double valve replacement. These special cardiovascular findings are discussed with regard to diagnosis and treatment.

Hemostasis management by use of Hepcon/HMS: increased bleeding without increased need for blood transfusion

BACKGROUND

Extracorporeal circulation forces complete anticoagulation, most frequently achieved by complete heparinization. Activated clotting time (ACT) is the gold standard for monitoring, although there is a lack of correlation between heparin plasma level and ACT. Several systems for the estimation of free heparin have been developed: in this study we focused investigating on the influence of the Hepcon/HMS system on postoperative bleeding and transfusion requirements.

METHODS

114 patients were randomly assigned to one group monitored by use of Hepcon/HMS (group hepcon) and another group by use of ACT (ACT group); 7 patients were excluded due to re-exploration. 12 patients did not receive aprotinin; this part of the study was stopped early due to massive increased bleeding. 46 and 49 patients of groups hepcon and ACT, respectively, received aprotinin.

RESULTS

Using aprotinin, in group hepcon total administered heparin was elevated by 13 % in contrast to group ACT while administered protamine was reduced by 20%. The ratio of antagonization was 82 +/- 17 % and 51 +/- 12 %, respectively. Coagulation parameters were not influenced except for increased postoperative ACT and PTT in the hepcon group. Bleeding of patients in that group was significantly increased during the first 6 hours, which led to an increased autologous retransfusion. Need for substitution of other blood components was not increased postoperatively.

CONCLUSIONS

Use of the Hepcon/HMS-system for monitoring of heparinization during extracorporeal circulation is possible without increased risk of thromboembolism. Postoperative blood loss was slightly but significantly increased but there was no need for more heterogenous transfusion.