Valve-Related Complications in TAVI Leading to Emergent Cardiac Surgery.

Transcatheter aortic valve implantation (TAVI) is now a standard procedure for the treatment of symptomatic aortic valve stenosis in many patients. In Germany, according to the annual reports from the German Institute for Quality Assurance and Transparency in Healthcare (Institut für Qualitätssicherung und Transparenz im Gesundheitswesen), the rate of serious intraprocedural complications, such as valve malpositioning or embolization, coronary obstruction, aortic dissection, annular rupture, pericardial tamponade, or severe aortic regurgitation requiring emergency cardiac surgery has decreased markedly in recent years from more than 5.5% in 2012 to 2.0% in 2019. However, with increased use, the total number of adverse events remains about 500 per year, about 100 of which require conversion to sternotomy. These, sometimes, fatal events can occur at any time and are still challenging. Therefore, the interdisciplinary TAVI heart team should be prepared and aware of possible rescue strategies.

Elucidation of the genetic causes of bicuspid aortic valve disease.

AIMS: The present study aims to characterize the genetic risk architecture of bicuspid aortic valve (BAV) disease, the most common congenital heart defect. METHODS AND RESULTS: We carried out a genome-wide association study (GWAS) including 2236 BAV patients and 11 604 controls. This led to the identification of a new risk locus for BAV on chromosome 3q29. The single nucleotide polymorphism rs2550262 was genome-wide significant BAV associated (P = 3.49 × 10-08) and was replicated in an independent case-control sample. The risk locus encodes a deleterious missense variant in MUC4 (p.Ala4821Ser), a gene that is involved in epithelial-to-mesenchymal transformation. Mechanistical studies in zebrafish revealed that loss of Muc4 led to a delay in cardiac valvular development suggesting that loss of MUC4 may also play a role in aortic valve malformation. The GWAS also confirmed previously reported BAV risk loci at PALMD (P = 3.97 × 10-16), GATA4 (P = 1.61 × 10-09), and TEX41 (P = 7.68 × 10-04). In addition, the genetic BAV architecture was examined beyond the single-marker level revealing that a substantial fraction of BAV heritability is polygenic and ∼20% of the observed heritability can be explained by our GWAS data. Furthermore, we used the largest human single-cell atlas for foetal gene expression and show that the transcriptome profile in endothelial cells is a major source contributing to BAV pathology. CONCLUSION: Our study provides a deeper understanding of the genetic risk architecture of BAV formation on the single marker and polygenic level.

Transcatheter Tricuspid Valve Repair in Prohibitive Risk Patients: Impact on Quality of Life and Major Organ Systems.

BACKGROUND: Percutaneous repair for severe tricuspid regurgitation (TR) is emerging as a viable option, but patient selection is challenging and predetermined by comorbidities. This study evaluated mid-term outcomes of transcatheter tricuspid valve repair (TTVR) in very sick inoperable patients and explored the concept of risk-based therapeutic futility. METHODS: TTVR patients treated in our centre were prospectively assigned to prohibitive-risk (PR) and high-risk (HR) subgroups, based on Society of Thoracic Surgeons (STS) Score, frailty indices, and major organ system compromise. Efficacy and safety outcomes were compared at baseline, 30 days, and 6 months. RESULTS: Thirty-three patients (mean age 81.9 ± 5.1 years) completed follow-up from May 2021 to March 2022: 18 PR (mean STS Score 15.5 ± 7%) and 15 HR (mean STS Score 6.4 ± 1.7%). The primary efficacy end point of at least 1 grade of TR reduction by 30 days was recorded in 93.9% of all patients, with no device-related adverse events. Improvement in initial New York Heart Association functional class III/IV occurred in 74% of PR and 93% of HR patients. Six-minute walk test increased by 81 ± 43.6 metres (P < 0.001) and 85.8 ± 47.9 metres (P < 0.001), respectively. Renal function tests improved by 15% (P = 0.048) and 7% (P = 0.050), while liver enzymes decreased by 18% (P = 0.020) and 28% (P = 0.052). Right ventricular systolic function increased in both subgroups by at least 24% (P < 0.001). Six-month mortality was 12.1%, with 6 hospitalisations for acute heart failure. CONCLUSIONS: TR reduction significantly affected quality of life, functional capacity, cardiac remodelling, and multiorgan involvement similarly in PR and HR patients. TTVR is feasible in very sick symptomatic patients, regardless of predicted risk.

Transcatheter aortic valve implantation in severe calcified annulus using the Lotus valve system: Increased incidence of fatal major vascular complications.

OBJECTIVES: This study reports the outcome of a highly selected transcatheter aortic valve implantation (TAVI) population. BACKGROUND: In patients with aortic valve stenosis and severe calcification of the left ventricular outflow tract and/or the annulus, the Boston Scientific Lotus valve provided a low paravalvular leakage rate omitting the risk of annular rupture. METHODS: Until now more than 3,600 TAVI procedures were performed at our institution. Between 8/2015 and 2/2017, 634 TAVI procedures were performed, of which 80 TAVI patients with severe calcifications consecutively received the Lotus valve. Valve Academic Research Consortium (VARC)-2 criteria of these procedures were prospectively documented in our institutional TAVI registry. One year follow-up for the Lotus treated patients was completed. RESULTS: Mean age was 82.0 ± 5.5 years. Device success was 95.0%. Conversion was required in two cases (2.5%). New permanent pacemaker implantation rate was 33.3%. Vascular complications occurred more frequent in comparison to non-Lotus treated patients (13.8 vs. 8.1%; p < .05): five minor and six major vascular complications (6.3 and 7.5%), including four fatal aortic injuries (three acute aortic dissections type A, one rupture of the aortic arch). Seventy-two-hour and 30-day mortality rates were also higher in Lotus patients (6.3 and 12.5% vs. 0.3 and 2.5%; each p < .05). One-year mortality in Lotus patients was 22.5%. CONCLUSIONS: In TAVI procedures with the Lotus valve occurrence of vascular complications including lethal aortic injuries and mortality rates were considerably high. Furthermore, in every TAVI procedure careful examination of the aorta should be mandatory and be a part of planning it.

Feasibility of transcatheter aortic valve implantation in patients with coronary heights ≤7 mm: insights from the transcatheter aortic valve implantation Karlsruhe (TAVIK) registry.

OBJECTIVES: Transcatheter aortic valve implantation (TAVI) in patients with low coronary heights is generally denied but is not impossible. Information about these high-risk procedures is sparse. METHODS: Since May 2008, data of more than 3000 patients who had TAVI were prospectively collected in the institutional TAVI Karlsruhe registry. Characteristics, peri- and postoperative outcome of patients with low coronary heights of ≤7 mm were analysed according to the Valve Academic Research Consortium-2. RESULTS: Eighty-six patients with an average coronary height of 6.4 ± 1.1 mm (mean age 81.0 ± 5.3 years, logistic EuroSCORE I 19.6 ± 13.3%) were treated. TAVI was performed in 72 transfemoral (83.7%) and 14 transapical (16.3%) cases using 44 CoreValve/Evolut R (51.2%), 21 Sapien XT/S3 (24.4%), 14 ACURATE (16.3%), 5 Lotus (5.8%) and 2 Portico (2.3%) prostheses. Ten procedures were valve-in-valve (VinV) TAVI (VinV, 11.6%). The 72-h, 30-day, 1-year and follow-up (3.0 ± 1.6 years) mortality rates were 2.3%, 8.0%, 10.5% and 26.7%, respectively. Within 30 days, 4 cardiac deaths and 3 non-cardiac deaths occurred (4.7% and 3.5%). Three coronary obstructions (3.5%) occurred-2 during VinV TAVI. One patient was connected to extracorporeal circulation that could not be weaned later due to an unsuccessful percutaneous coronary intervention. Another patient, the only conversion (1.2%), required delayed surgical valve replacement. The third patient died of right heart failure after aortic dissection. The procedural success rate was 95.3%. VinV procedures were associated with increased follow-up deaths (P < 0.001; hazard ratio 7.96). CONCLUSIONS: Coronary-related complications in TAVI procedures in patients with coronary heights ≤7 mm occurred less frequently, but once they occurred, they were serious. These TAVI procedures are feasible, with a high procedural success rate, but meticulous preoperative planning should be mandatory. In VinV procedures, the follow-up mortality rate is increased; therefore, we do not recommend these procedures.

Cross-clamping a porcelain aorta: an alternative technique for high-risk patients.

BACKGROUND: Aortic cross-clamping in patients with porcelain aorta is associated with high mortality and morbidity rates. The aim is to establish a new approach to improve the outcome in this high-risk population. METHODS: Between September 2007 and November 2012, 42 patients with an aortic (N.=33; 81.3±6.4 years) or mitral valve disease (N.=9; 80.3±5.7) combined with a porcelain aorta underwent aortic (AVR) or mitral valve replacement (MVR). After arterial cannulation via distal aortic arch or femoral artery, longitudinal aortotomy under total cardiopulmonary bypass (CPB) was performed. The aorta was slowly clamped, thus mobilized atherosclerotic material could leave the aorta through the open incision. Subsequent to the actual operation, the aorta was gradually unclamped. Again, plaques were flushed out via the still open aortotomy ("open proximal ascending aorta"). RESULTS: Intraoperatively, no technical no problems occurred. Mean CPB time was 92.2±27.9 min (AVR) and 92.3±36.3 min (MVR); cardiac ischemia time was 74.3±26.7 min (AVR) and 77.1±31.6 min (MVR). Surgical revision was necessary in three patients (7.1%) due to major bleedings. Two AVR-patients suffered from minor stroke and one MVR-patient from major stroke (neurological deficit rate =7.1%). Transient ischemic attacks occurred in three patients (7.1%), another three patients (7.1%) required temporary hemofiltration. Neither gastrointestinal disorders nor respiratory failure or valve-related problems were noted. 30-day mortality was 6.9%. CONCLUSIONS: Cross-clamping with "open proximal ascending aorta" is effective and the incidence of stroke and systemic embolization in patients with porcelain aorta is low compared to literature.

Mortality in patients with acute aortic dissection type A: analysis of pre- and intraoperative risk factors from the German Registry for Acute Aortic Dissection Type A (GERAADA).

OBJECTIVES: Acute aortic dissection type A (AADA) is an emergency with excessive mortality if surgery is delayed. Knowledge about independent predictors of mortality on surgically treated AADA patients is scarce. Therefore, this study was conducted to identify pre- and intraoperative risk factors for death. METHODS: Between July 2006 and June 2010, 2137 surgically treated patients with AADA were enrolled in a multicentre, prospective German Registry for Acute Aortic Dissection type A (GERAADA), presenting perioperative status, operative strategies, postoperative outcomes and AADA-related risk factors for death. Multiple logistic regression analysis was performed to identify the influence of different parameters on 30-day mortality. RESULTS: Overall 30-day mortality (16.9%) increased with age [adjusted odds ratio (OR) = 1.121] and among patients who were comatose (adjusted OR = 3.501) or those who underwent cardiopulmonary resuscitation (adjusted OR = 3.751; all P < 0.0001). The higher the number of organs that were malperfused, the risk for death was (adjusted OR for one organ = 1.651, two organs = 2.440, three organs or more = 3.393, P < 0.0001). Mortality increased with longer operating times (total, cardiopulmonary bypass, cardiac ischaemia and circulatory arrest; all P < 0.02). Arterial cannulation site for extracorporeal circulation, operative techniques and arch interventions had no significant impact on 30-day mortality (all P > 0.1). No significant risk factors, but relevant increases in mortality, were determined in patients suffering from hemiparesis pre- and postoperatively (each P < 0.01), and in patients experiencing paraparesis after surgery (P < 0.02). CONCLUSIONS: GERAADA could detect significant disease- and surgery-related risk factors for death in AADA, influencing the outcome of surgically treated AADA patients. Comatose and resuscitated patients have the poorest outcome. Cannulation sites and operative techniques did not seem to affect mortality. Short operative times are associated with better outcomes.

Percutaneous extracorporeal life support in patients with circulatory failure: results of the German Lifebridge Registry.

OBJECTIVES: Mortality rates remain high in patients with cardiogenic shock or acute refractory circulatory failure. Extracorporeal life support (ECLS) has been recently introduced into clinical practice for treatment of refractory hypotension in selected patients in combination with rapid restoration of gas exchange. The aim of this study was to evaluate the procedural performance and safety of the automated Lifebridge ECLS system (Zoll Lifebridge GmbH). METHODS: A total of five tertiary cardiovascular centers located in Germany contributed data to this registry (n = 54 patients). Data were collected using a standardized case report form to record clinical characteristics, demographic, procedural, and follow-up data. Patients were included if they were in circulatory crisis (caused by cardiogenic shock or ongoing resuscitation) in an acute setting or in an elective setting during high-risk percutaneous intervention. RESULTS: The Lifebridge device was successfully used in all patients. During elective use, no complications occurred besides 1 minor vascular injury. All elective patients were successfully weaned from the device and alive at the primary endpoint after 30 days. In the emergency setting, 85% of the patients were successfully weaned from the device and 49% of the patients were alive after 30 days. Relevant bleeding resulting in transfusion of red blood cells occurred in 5% of patients. CONCLUSION: In this observational study, we report data from the real-world use of a novel automated ECLS system. Elective use of Lifebridge was feasible and safe without major side effects. In the emergency setting, mortality rates were high; however, stabilization of the selected patients was safe and feasible.

Contractile properties of the right atrial myofilaments in patients with myxomatous mitral valve degeneration.

BACKGROUND: Myxomatous degeneration of the mitral valve is a common pathological finding in mitral valve surgery and the most common reason for severe mitral valve regurgitation. Considering the importance of right ventricular remodeling and global function after mitral valve surgery we tried to elucidate a possible association of myxomatous mitral valve and impairment of right atrial and ventricular function, which might have an impact on global ventricular performance after mitral valve surgery. METHODS: Right atrial tissue was harvested from 47 patients undergoing mitral valve surgery. We took the trabeculae from the right auricle, which was resected at the right auricle for implementation of extracorporal circulation. The tissue was skinned and prepared in a 24 h-lasting procedure to create small fibers for hinging them in the "muscle machine", an experimental set-up, created for pCa-force measurements. RESULTS: Patients without myxomatous mitral valve developed significantly more force (4.0 mN ± 0.8 mN) at the highest step of calcium concentration compared to 2.7 mN ± 0.4 mN in group of patients with myxomatous valve degeneration (p 0.03). Calcium sensitivity in the myxomatous valve group was at pCa 6.0 and in the non-myxomatous group at pCa 5. Furthermore we observed a significant difference in ejection fraction (EF) among the groups: 49% in the non-myxomatous group versus 57% in the myxomatous group (p 0.03). In the non-myxomatous group 5 patients had diastolic dysfunction grade I-II (22,7%), in group I 10 patients (40%). This was also significant (p 0.04). CONCLUSIONS: Patients with myxomatous mitral valve degeneration seem to have reduced force capacities. Calcium sensitivity is higher compared to the non-myxomatous group, which might be a compensatory mechanism to cover the physiological demand. Furthermore we suggest a higher incidence of diastolic dysfunction in patients with myxomatous mitral valve degeneration, which might have an impact on ventricular remodeling after mitral valve surgery.

How to do it: direct true lumen cannulation technique of the ascending aorta in acute aortic dissection type A.

In acute aortic dissection type A (AADA), direct true lumen cannulation (DTLC) of the ascending aorta is a fast and safe cannulation site providing antegrade perfusion of the supraaortic and visceral vessels. An Overholt clamp is passed around the ascending aorta to place a Mersilene tape for later securing of the arterial cannula. After draining venous blood into the cardiopulmonary bypass system (CPB), the ascending aorta is transected and the aortic lumen inspected. The true lumen is identified and an arterial cannula inserted directly. Finally, the cannula is secured with the previously placed tape and CPB is initiated. DTLC can be used as arterial cannulation standard technique in operations for AADA.

Transmurality of scar influences the effect of a hybrid-intervention with autologous bone marrow cell injection and aortocoronary bypass surgery (MNC/CABG) in patients after myocardial infarction.

BACKGROUND: Cell therapy (CTx) is a strategy to support cardiac regeneration after myocardial infarction (MI). Thus far, clinical studies provided mixed results. Here, we investigated whether transmurality of the infarct may play a relevant role. METHODS: 18 patients (63 ± 3 years, 15 male) undergoing elective coronary artery bypass graft (CABG) surgery 2.2 ± 0.7 months post MI participated. 10 had transmural and 8 non-transmural infarct scars assessed by Tc-99m-MIBI Single-Photon Emission Computed Tomography (SPECT) and F18-FDG-Positron-Emission-Tomography (PET). During surgery, 10 ml of sternal bone marrow were obtained, mononuclear cells (MNC) were isolated. At the end of surgery MNC were injected into the infarctions' center and border zones (10 injections, 2 ml total, 6.6 ± 1.3 × 10(7) MNC). RESULTS: No major complications attributable to cell therapy were observed. The sizes of non-transmural scars were reduced at 3 and 24 months after treatment (7.7 ± 1.1% and 5.5 ± 1.8 vs. 17.5 ± 4.9%, P=0.05 and P=0.04), while transmural scars remained unchanged (23.5 ± 2.6% and 23.8±3.2 vs. 23.5 ± 2.6%, P>0.99 and P=0.95). A trend towards improved LVEF was seen in patients with non-transmural scars (MRI: 48.8 ± 5.1% vs. 30.6 ± 8.7%, P=0.3; SPECT: 54.1 ± 3.1 vs. 41.0 ± 4.0, P=0.086), but not in patients with transmural scars (MRI: 36.7 ± 3.9 vs. 34.3 ± 5.0, P=0.63, SPECT: 37.8 ± 3.1 vs. 37.9 ± 2.3%, P=0.96). CONCLUSIONS: A single hybrid intervention of MNC recovery, purification and injection with CABG-surgery (MNC/CABG) may be an attractive modality for cell therapy. However, no regeneration of avital transmural scar tissue seems to occur, while the contribution of MNC to improved perfusion in non-transmural myocardial infarct scars remains to be determined.

Successful management of fulminant pulmonary embolism using a novel portable extracorporeal life support system.

A 46-year-old man presented to the emergency room with pain in his left leg, dyspnea, and general cyanosis. During examination he collapsed and required resuscitation. Under suspicion of pulmonary embolism, a new portable "click 'n run" extracorporeal life support system (LIFEBRIDGE-B(2)T [Medizintechnik AG, Ampfing, Germany]) was implanted by the femoral vessels under resuscitation within 15 minutes of presentation. The patient was stabilized, despite severe decompensation (pH, 6.8), and could be transferred for a computed tomographic scan, which confirmed massive pulmonary embolism. Still connected to the life support system, the patient was transferred to the operating room. After a pulmonary thrombectomy was performed, the patient recovered without any organ dysfunction. A portable emergency extracorporeal life support may change clinical practice in the treatment of patients with severe hemodynamic deterioration at emergency care hospitals.

Composite risk scores and depression as predictors of competing waiting-list outcomes: the Waiting for a New Heart Study.

We evaluated two composite risk scores, (Heart Failure Survival Score, HFSS; German Transplant Society Score, GTSS), and depression as predictors of mortality and competing waiting-list outcomes [high-urgency transplantation (HU-HTx), elective transplantation, delisting because of clinical improvement] in 318 heart transplant (HTx) candidates (18% women; aged 53 ± 11 years) from 17 hospitals and newly registered with Eurotransplant. Demographic variables and depression (Hospital Anxiety and Depression Scale, HADS) were assessed using questionnaires. Variables to compute HFSS and GTSS, age, medications, and outcomes were provided by Eurotransplant. At 12 months, 33 patients died, 83 received urgent HTx, 30 elective HTx, and 17 were delisted because of improvement. Applying cause-specific Cox regressions, only the HFSS was significantly associated with 1-year mortality [HR = 0.64 (95% CI = 0.43-0.95), P = 0.029]. The GTSS was the strongest predictor of HU-HTx [HR= 1.02 (95% CI = 1.01-1.02), P < 0.001]. Low depression scores contributed significantly to clinical improvement, even after adjusting for age and risk scores [HADS: HR = 0.12 (95% CI = 0.02-0.89), P = 0.039]. These findings confirm the usefulness of composite risk scores for the prediction of mortality and HU-HTx, validating both scores for their intended use. The finding that depression was an independent predictor of the waiting-list outcome clinical improvement suggests that considering patients' psychological attributes in addition to their medical characteristics is advisable.

Isoform specificity of cardiac glycosides binding to human Na+,K+-ATPase alpha1beta1, alpha2beta1 and alpha3beta1.

Cardiac glycosides inhibit the Na(+),K(+)-ATPase and are used for the treatment of symptomatic heart failure and atrial fibrillation. In human heart three isoforms of Na(+),K(+)-ATPase are expressed: alpha(1)beta(1), alpha(2)beta(1) and alpha(3)beta(1). It is unknown, if clinically used cardiac glycosides differ in isoform specific affinities, and if the isoforms have specific subcellular localization in human cardiac myocytes. Human Na(+),K(+)-ATPase isoforms alpha(1)beta(1), alpha(2)beta(1) and alpha(3)beta(1) were expressed in yeast which has no endogenous Na(+),K(+)-ATPase. Isoform specific affinities of digoxin, digitoxin, beta-acetyldigoxin, methyldigoxin and ouabain were assessed in [(3)H]-ouabain binding assays in the absence or presence of K(+) (each n=5). The subcellular localizations of the Na(+),K(+)-ATPase isoforms were investigated in isolated human atrial cardiomyocytes by immunohistochemistry. In the absence of K(+), methyldigoxin (alpha(1)>alpha(3)>alpha(2)) and ouabain (alpha(1)=alpha(3)>alpha(2)) showed distinct isoform specific affinities, while for digoxin, digitoxin and beta-acetyldigoxin no differences were found. In the presence of K(+), also digoxin (alpha(2)=alpha(3)>alpha(1)) and beta-acetyldigoxin (alpha(1)>alpha(3)) had isoform specificities. A comparison between the cardiac glycosides demonstrated highly different affinity profiles for the isoforms. Immunohistochemistry showed that all three isoforms are located in the plasma membrane and in intracellular membranes, but only alpha(1)beta(1) and alpha(2)beta(1) are located in the T-tubuli. Cardiac glycosides show distinct isoform specific affinities and different affinity profiles to Na(+),K(+)-ATPase isoforms which have different subcellular localizations in human cardiomyocytes. Thus, in contrast to current notion, different cardiac glycoside agents may significantly differ in their pharmacological profile which could be of hitherto unknown clinical relevance.

Reevaluation of direct true lumen cannulation in surgery for acute type A aortic dissection.

BACKGROUND: The optimal mode of arterial cannulation in acute type A aortic dissection is controversial. We retrospectively investigated our experience with direct true lumen cannulation as an alternative to standard cannulation procedures. METHODS: From April 2004 to August 2007, 29 patients (20 men, 9 women; mean age of 63.2 +/- 12.6 years) underwent emergency operation for acute type A aortic dissection with direct true lumen cannulation. After venous drainage into the venous reservoir, the ascending aorta was completely transected in the region between the sinotubular junction and innominate artery. After visual and digital identification of the true lumen, the arterial cannula was directly inserted into the true lumen and secured with a ligature. RESULTS: Mean aortic cross-clamp time was 77.4 +/- 28.3 minutes, and hypothermic circulatory arrest for the distal anastomosis was 10.4 +/- 11.0 minutes. All patients survived the surgical procedure. No surgical problems were observed by applying this strategy. Mean intensive care unit stay was 4.0 +/- 3.5 days. Postoperative mean ventilation time was 43.3 +/- 41.3 hours. One patient had a prolonged postoperative course and required permanent ventilation. Two patients required temporary hemofiltration. Neurologic disorders occurred in 6 patients: 2 had severe cerebral hypoxia, and 4 had temporary hemiplegia under good regression. All patients were alive at discharge. CONCLUSIONS: Direct true lumen cannulation is a promising surgical strategy for emergency operations in type A aortic dissection. It is a simple, quick, and safe method to provide antegrade flow through the true aortic lumen.

Effects of the beta3-adrenergic agonist BRL 37344 on endothelial nitric oxide synthase phosphorylation and force of contraction in human failing myocardium.

BACKGROUND: In nonfailing myocardium, beta(3)-adrenergic signaling causes a decrease in contractility via endothelial nitric oxide synthase (eNOS) activation and nitric oxide (NO) release. This study investigates the hypothesis that beta(3)-adrenergic signaling undergoes alterations in failing myocardium. METHODS: We compared eNOS- and beta(3)-adrenoceptor expression using Western blot analysis in human nonfailing myocardium versus failing myocardium. With the use of immunohistochemistry, we investigated the distribution of the beta(3)-adrenoceptor protein and eNOS translocation and phosphorylation under basal conditions. beta(3)-adrenergic, eNOS activation, and inotropy were measured in failing myocardium using BRL37344 (BRL, a beta(3)-adrenoceptor agonist). RESULTS: beta(3)-adrenoceptor expression was increased in failing myocardium. Under basal conditions, Akt- and eNOS(Ser1177) phosphorylation were reduced in failing myocardium. During stimulation with BRL in failing myocardium, a further dephosphorylation of eNOS(Ser1177) and Akt was observed, whereas eNOS(Ser114) phosphorylation was increased. These results suggest a deactivation of eNOS via beta(3)-adrenergic stimulation. Nevertheless, BRL decreased contractility in failing myocardium, but this effect was not observed in the presence of the NO blocker L-NMA. In failing myocardium, the beta(3)-adrenoceptor was predominantly expressed in endothelial cells. In the cardiomyocytes, the beta(3)-adrenoceptor was mainly located at the intercalated disks. CONCLUSION: In failing cardiomyocytes, beta(3)-adrenergic stimulation seems to deactivate rather than activate eNOS. At the same time, beta(3)-adrenergic stimulation induced a NO-dependent negative inotropic effect. Because beta(3)-adrenoceptors are expressed mainly in the endothelium in failing myocardium, our observations suggest a paracrine-negative inotropic effect via NO liberation from the cardiac endothelial cells.

Role of balloon occlusion for mononuclear bone marrow cell deposition after intracoronary injection in pigs with reperfused myocardial infarction.

AIMS: In clinical studies on cell therapy for acute myocardial infarction (MI), cells are usually applied by intracoronary infusion with balloon (IC/B). To test the utility of balloon occlusion, mononuclear bone marrow cell (MNC) retention after intracoronary infusion without balloon (IC/noB) was compared with IC/B and intramyocardial (IM) injection. METHODS AND RESULTS: Four hours after LAD ligation in male pigs, reperfusion was allowed (confirmed by coronary angiography). Five days later, 1 x 10(8) autologous (111)Indium-labelled MNC were injected IC/noB (n = 4), IC/B (n = 4), or IM (n = 4). At 1 h the fraction of injected MNC that was detected in the heart was 4.1 +/- 1.1% after IC/noB injection, 6.1 +/- 2.5% after IC/B injection (P = 0.19), and 20.7 +/- 2.3% after IM injection (P < 0.001 vs. IC/noB and IC/B). At 24 h it was 3.0 +/- 0.6% (IC/noB), 3.3 +/- 0.5% (IC/B, P = 0.43), and 15.0 +/- 3.1% (IM, P < 0.001 vs. IC/noB and IC/B). Dynamic scintigrammes during each of four consecutive IC/B injections showed a rapid 19.6 +/- 8.0% cell loss during balloon inflation (no-flow period, phase 1) and a rapid 36.6 +/- 17.8% cell loss after balloon deflation (re-flow period, phase 2). After each of four consecutive IC/noB injections the peak cell deposit was lower, followed by one phase of rapid cell loss (30.9 +/- 11.0% after 6 min). After IM injection only a slow linear cell loss was observed (9.7% per h). In histology, PKH-67 labelled cells only rarely had passed the endothelial barrier after 24 h after IC injection, while they were exclusively found in the interstitium after IM injection. CONCLUSION: The observation of a similar cell persistence after IC injections with and without balloon occlusion suggests that the balloon procedures currently applied in clinical studies are not necessary for cell deposit. If longer term persistence of cells plays a role for the clinical benefit of cardiac cell therapy, IM injection may be superior to IC applications.