In vitro Haemokompatibilitätstestung cardiovaskulärer Biomaterialien

Die Bedeckung cardiovaskulärer Bioprothesen mit autologen Endothel hat zum Ziel die Hämokompatibilität zu verbessern. Ziel dieser Arbeit ist es das Endothelialisierungspotential Glutaraldehyd-fixierter Herzklappenprothesen, sowie die zellulären Funktionen adhärenter Endothelzellen zu untersuchen. Weiterhin wurde der Einfluß einer zweizeitigen Besiedelung von humanen Fibroblasten und Endothelzellen auf deren fuktionelle Eigenschaften untersucht. Adhärenz und Morphologie der adhärierten Zellen wurde mittels Rasterelektronenmikroskopie und Immunhistochemie untersucht. Es konnte reproduzierbar eine vollständige Bedeckung von Glutaraldehyd-fixierten und detoxifizierten Herzklappenprothesen erreicht werden. Eine Analyse der direkt auf dem Material adhärenten Zellen ergab nicht-proliferative Zellen, die jedoch in der Lage waren auf inflammatorische Stimulation mit Interleukin-6 Sekretion, sowie mit Adhärenz inflammatorischer Zellen zu reagieren. Die Endothelzellen zeigten weiterhin erhaltene antithrombogene Eigenschaften, was mittels quantitativer Thrombozytenadhäsion und Sekretion von Prostacyclin gezeigt werden konnte. Eine Vorbesiedelung des Materials mit vaskulären Myofibroblasten gefolgt von Endothelzellen induzierte deren Proliferation und verbesserte inflammatorische sowie antithrombotische Eigenschaften. Cardiovaskuläre Biomaterialien unterscheiden sich deutlich bezüglich des Potentials die Adhärenz humaner Endothelzellen zu ermöglichen. Erfolgreich endothelialisierte Biomaterialien zeigen zelluläre Eigenschaften die die klinische Effektivität dieser Materialien verbessern könnten. Zweizeitige Besiedelung ermöglicht regeneratives Potential und verbessert die zellulären Eigenschaften der adhärenten Endothelzellen

Assessment of Association Between Venous Occlusion and Infection of Cardiac Implantable Electronic Devices

The increasing number of patients treated with cardiac implantable electronic devices (CIEDs) and indications for complex pacing requires system revisions. Currently, data on venous patency in repeat CIED surgery involving lead (re)placement or extraction are largely missing. This study aimed to assess venous patency and risk factors in patients referred for repeat CIED lead surgery, emphasizing CIED infection. All consecutive patients requiring extraction, exchange, or additional placement of ≥1 CIED leads during reoperative procedures from January 2015 to March 2020 were evaluated in this retrospective study. Venography was performed in 475 patients. Venous patency could be assessed in 387 patients (81.5%). CIED infection with venous occlusion was detected in 74 patients compared with venous occlusion without infection in 14 patients (P < .05). Concerning venous patency, novel oral anticoagulant medication appeared to be protective (P < .05; odds ratio [OR]: .35). Infection of the CIED appeared to be strongly associated with venous occlusion (OR: 16.0). The sensitivity was only 64.15%, but the specificity was 96.1%. Number of leads involved and previous CIED procedures were not associated with venous occlusion. In conclusion, in patients with CIED, venous occlusion was strongly associated with device infection, but not with the number of leads or previous CIED procedures

Multi‐organ dysfunction syndrome in patients undergoing extracorporeal life support

Background Multiple organ failure is a common complication in patients undergoing ECLS significantly affecting patient outcomes. Gaining knowledge about the mechanisms of onset, clinical course, risk factors, and potential therapeutic targets is highly desirable. Methods Data of 354 patients undergoing ECLS with one-, two, three-, and four organ failures were retrospectively analyzed. Incidence of multiple organ dysfunction (MODS), its impact on survival, risk factors for its occurrence, and the impact of proinflammatory mediators on the occurrence of MODS in patients undergoing ECLS were investigated. Results The median follow-up was 66 (IQR 6; 820) days. 245 (69.2%) patients could be weaned from ECLS, 30-day survival and 1-year survival were 194 (54.1%) and 157 (44.4%), respectively. The duration of mechanical support was 4 (IQR 2; 7) days in the median. Increasing severity of MODS resulted in significant prolongation of mechanical circulatory support and worsening of the outcome. Liver dysfunction had the strongest impact on patient mortality (OR = 2.5) and survival time (19 vs 367 days). The serum concentration of analyzed interleukins rose significantly with each, additional organ affected by dysfunction (p < 0.001). All analyzed proinflammatory cytokines showed significant predictivity relative to the occurrence of MODS with interleukin 8 serum level prior to ECLS showing the strongest predictive potential for the occurrence of MODS (AUC 0.78). Conclusion MODS represents a frequent complication in patients undergoing ECLS with a significant impact on survival. Proinflammatory cytokines show prognostic capacity regarding the occurrence and severity of multi-organ dysfunction

Abnormal P‐wave terminal force in lead V 1 is a marker for atrial electrical dysfunction but not structural remodelling

Aims There is a lack of diagnostic and therapeutic options for patients with atrial cardiomyopathy and paroxysmal atrial fibrillation. Interestingly, an abnormal P-wave terminal force in electrocardiogram lead V1 (PTFV1) has been associated with atrial cardiomyopathy, but this association is poorly understood. We investigated PTFV1 as a marker for functional, electrical, and structural atrial remodelling. Methods and results Fifty-six patients with acute myocardial infarction and 13 kidney donors as control cohort prospectively underwent cardiac magnetic resonance imaging to evaluate the association between PTFV1 and functional remodelling (atrial strain). To further investigate underlying pathomechanisms, right atrial appendage biopsies were collected from 32 patients undergoing elective coronary artery bypass grafting. PTFV1 was assessed as the product of negative P-wave amplitude and duration in lead V1 and defined as abnormal if ≥4000 ms*μV. Activity of cardiac Ca/calmodulin-dependent protein kinase II (CaMKII) was determined by a specific HDAC4 pull-down assay as a surrogate for electrical remodelling. Atrial fibrosis was quantified using Masson's trichrome staining as a measure for structural remodelling. Multivariate regression analyses were performed to account for potential confounders. A total of 16/56 (29%) of patients with acute myocardial infarction, 3/13 (23%) of kidney donors, and 15/32 (47%) of patients undergoing coronary artery bypass grafting showed an abnormal PTFV1. In patients with acute myocardial infarction, left atrial (LA) strain was significantly reduced in the subgroup with an abnormal PTFV1 (LA reservoir strain: 32.28 ± 12.86% vs. 22.75 ± 13.94%, P = 0.018; LA conduit strain: 18.87 ± 10.34% vs. 10.17 ± 8.26%, P = 0.004). Abnormal PTFV1 showed a negative correlation with LA conduit strain independent from clinical covariates (coefficient B: −7.336, 95% confidence interval −13.577 to −1.095, P = 0.022). CaMKII activity was significantly increased from (normalized to CaMKII expression) 0.87 ± 0.17 to 1.46 ± 0.15 in patients with an abnormal PTFV1 (P = 0.047). This increase in patients with an abnormal PTFV1 was independent from clinical covariates (coefficient B: 0.542, 95% confidence interval 0.057 to 1.027, P = 0.031). Atrial fibrosis was significantly lower with 12.32 ± 1.63% in patients with an abnormal PTFV1 (vs. 20.50 ± 2.09%, P = 0.006), suggesting PTFV1 to be a marker for electrical but not structural remodelling. Conclusions Abnormal PTFV1 is an independent predictor for impaired atrial function and for electrical but not for structural remodelling. PTFV1 may be a promising tool to evaluate patients for atrial cardiomyopathy and for risk of atrial fibrillation

Ablation of atrial fibrillation with the Epicor system: a prospective observational trial to evaluate safety and efficacy and predictors of success

<p>Abstract</p> <p>Background</p> <p>High intensity focused ultrasound (HIFU) energy has evolved as a new surgical tool to treat atrial fibrillation (AF). We evaluated safety and efficacy of AF ablation with HIFU and analyzed predictors of success in a prospective clinical study.</p> <p>Methods</p> <p>From January 2007 to June 2008, 110 patients with AF and concomitant open heart surgery were enrolled into the study. Main underlying heart diseases were aortic valve disease (50%), ischemic heart disease (48%), and mitral valve disease (18%). AF was paroxysmal in 29%, persistent in 31%, and long standing persistent in 40% of patients, lasting for 1 to 240 months (mean 24 months). Mean left atrial diameter was 50 ± 7 mm. Each patient underwent left atrial ablation with the Epicor system prior to open heart surgery. After surgery, the patients were treated with amiodarone and coumadin for 6 months. Follow-up studies including resting ECG, 24 h Holter ECG, and echocardiography were obtained at 6 and 12 months.</p> <p>Results</p> <p>All patients had successful application of the system on the beating heart prior to initiation of extracorporeal circulation. On average, 11 ± 1 ultrasound transducer elements were used to create the box lesion. The hand-held probe for additional linear lesions was employed in 83 cases. No device-related deaths occurred. Postoperative pacemaker insertion was necessary in 4 patients. At 6 months, 62% of patients presented with sinus rhythm. No significant changes were noted at 12 months. Type of AF and a left atrial diameter > 50 mm were predictors for failure of AF ablation.</p> <p>Conclusion</p> <p>AF ablation with the Epicor system as a concomitant procedure during open heart surgery is safe and acceptably effective. Our overall conversion rate was lower than in previously published reports, which may be related to the lower proportion of isolated mitral valve disease in our study population. Left atrial size may be useful to determine patients who are most likely to benefit from the procedure.</p

Lithological influences on contemporary and long-term regolith weathering at the Luquillo Critical Zone Observatory

Lithologic differences give rise to the differential weatherability of the Earth’s surface and globally variable silicate weathering fluxes, which provide an important negative feedback on climate over geologic timescales. To isolate the influence of lithology on weathering rates and mechanisms, we compare two nearby catchments in the Luquillo Critical Zone Observatory in Puerto Rico, which have similar climate history, relief and vegetation, but differ in bedrock lithology. Regolith and pore water samples with depth were collected from two ridgetops and at three sites along a slope transect in the volcaniclastic Bisley catchment and compared to existing data from the granitic Río Icacos catchment. The depth variations of solid-state and pore water chemistry and quantitative mineralogy were used to calculate mass transfer (tau) and weathering solute profiles, which in turn were used to determine weathering mechanisms and to estimate weathering rates. Regolith formed on both lithologies is highly leached of most labile elements, although Mg and K are less depleted in the granitic than in the volcaniclastic profiles, reflecting residual biotite in the granitic regolith not present in the volcaniclastics. Profiles of both lithologies that terminate at bedrock corestones are less weathered at depth, near the rock-regolith interfaces. Mg fluxes in the volcaniclastics derive primarily from dissolution of chlorite near the rock-regolith interface and from dissolution of illite and secondary phases in the upper regolith, whereas in the granitic profile, Mg and K fluxes derive from biotite dissolution. Long-term mineral dissolution rates and weathering fluxes were determined by integrating mass losses over the thickness of solid-state weathering fronts, and are therefore averages over the timescale of regolith development. Resulting long-term dissolution rates for minerals in the volcaniclastic regolith include chlorite: 8.9 × 10‾¹⁴ mol m‾² s‾¹, illite: 2.1 × 10‾¹⁴ mol m‾² s‾¹ and kaolinite: 4.0 × 10‾¹⁴ mol m‾² s‾¹. Long-term weathering fluxes are several orders of magnitude lower in the granitic regolith than in the volcaniclastic, despite higher abundances of several elements in the granitic regolith. Contemporary weathering fluxes were determined from net (rain-corrected) solute profiles and thus represent rates over the residence time of water in the regolith. Contemporary weathering fluxes within the granitic regolith are similar to the long-term fluxes. In contrast, the long-term fluxes are faster than the contemporary fluxes in the volcaniclastic regolith. Contemporary fluxes in the granitic regolith are generally also slightly faster than in the volcaniclastic. The differences in weathering fluxes over space and time between these two watersheds indicate significant lithologic control of chemical weathering mechanisms and rates

Early-BYRD: alternative early pacing and defibrillation lead replacement avoiding venous puncture

Abstract Background In cases of lead failure after implantation of pacemakers (PM) or implantable cardioverter defibrillators (ICD) early lead replacement may be challenging. Puncture of the subclavian vein bears possible complications such as pneumothorax, hematothorax, and damage of leads to be left in place. To avoid venous puncture PM or ICD leads were replaced using a flexible polypropylene sheath (Byrd-sheath). Method From January 2010 through December 2017, 55 patients underwent early lead exchange avoiding venous puncture. Early lead exchange for this study was defined as a reintervention within 14 days after the initial lead implantation. The connector of the malfunctioning lead was cut off, and stabilized by a stiff stylet. After having cut off the plastic knob of the stylet, the lead was passed through the polypropylene sheath and the latter advanced into the subclavian vein with gentle rotational movements to gain access to the subclavian vein. After lead removal the polypropylene sheath was replaced by a peel away sheath a new lead inserted. Results Overall, 23 defibrillation leads and 34 pacing leads (16 right atrial leads, 17 right ventricular leads, and 1 left ventricular lead) were successfully explanted. Access to the subclavian vein was uneventful, and blood loss minimal. Radiation exposure and fluoroscopy time were also negligible. Conclusion The Byrd-sheath technique proved to be safe and successful in providing vein access within 2 weeks after initial lead implantation using the previously implanted lead and thus avoiding puncture of the subclavian vein

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

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

25 Years' Experience with Redo Operations in Cardiac Surgery—Third-Time Sternotomy Procedures

Background Over the years, open heart surgery has become more complex, and especially reoperative surgery, more demanding. The risk of third-time or more sternotomy procedures is unclear. Methods We reviewed our institutional experience of 25 years based on two generations of cardiac surgeons in a German university medical center to document frequency, outcome, and complications of the various types of open heart procedures. Results Overall, we included 104 patients with a mean age of 6413 years. The EuroSCORE II (European System for Cardiac Operative Risk Evaluation) calculated an average mortality risk of 15.7 +/- 15.4%. Subgroup comparison of isolated coronary artery bypass grafting (CABG), aortic valve replacement, and mitral valve replacement procedures did not delineate significantly different risk profiles except for the incidence of acute myocardial infarction, which was present in every second patient (53.3%) scheduled for CABG surgery. The time interval to previous surgery was 4.7 +/- 6.3 years on average. Most frequent surgical procedures were valve operations, which were accomplished in 72 patients (69.2%), whereas coronary bypass surgery was performed in 23 patients (22.1%) only. Combined procedures were performed in 27 patients. Complex aortic arch replacement with a frozen elephant trunk procedure was necessary in six patients. Overall, 30-day survival was 81.7%. Conclusion In conclusion, third-time and more sternotomy procedures offer acceptable outcome and should therefore be considered in appropriate patients

Impact of normothermic perfusion and protein supplementation on human endothelial cell function during organ preservation

BACKGROUND: Hypothermia-induced changes in endothelial cell (EC) morphology and function after organ storage may influence the initial outcome and development of transplant-associated coronary artery disease. METHODS: Human saphenous vein ECs were incubated with saline (NaCl), University of Wisconsin (UW), and histidine-tryptophan-ketoglutarate (HTK) solution, with and without protein additives, at 4 degrees C and 37 degrees C. After 6 hours, ECs were recultivated for 24 and 48 hours with culture medium (reperfusion). Mitochondrial activity, adenosine triphosphate concentration, cell count, and inflammatory responses were analyzed. RESULTS: Cold preservation did not affect the mitochondrial activity of ECs and allowed a complete regeneration of the metabolic turnover after reperfusion. However, under normothermic conditions the metabolism of the cells was influenced by time and type of preservation solution. While both the mitochondrial activity and cell count did not change after treatment with NaCl and culture medium, the metabolic turnover of cells treated with HTK and UW solution significantly increased (twofold) and decreased (twofold, p < 0.05), respectively, after reperfusion. The endothelial reactivity remained unchanged after treatment with NaCl and HTK. The addition of serum proteins significantly improved mitochondrial activity of cells treated with warm NaCl and HTK (p < 0.05). The UW-treated cells burned out through a significant up-regulation of the ATP concentration resulting in a complete metabolic regression after reperfusion and induction of apoptosis. CONCLUSIONS: Normothermic preservation in UW prevented regeneration of ECs, while treatment with HKT solution did not irreversibly affect mitochondrial activity of ECs and allowed complete regeneration of metabolism and function. Serum proteins improved the preservation effect of HTK and NaCl