Wolfgang Schillinger

Alterations of Sarcoplasmic Reticulum Proteins in Failing Human Dilated Cardiomyopathy

BACKGROUND Previous studies provide considerable evidence that excitation-contraction coupling may be disturbed at the level of the sarcoplasmic reticulum (SR) in the failing human heart. Disturbed SR function may result from altered expression of calcium-handling proteins. METHODS AND RESULTS Levels of SR proteins involved in calcium release (ryanodine receptor), calcium binding (calsequestrin, calreticulin), and calcium uptake (calcium ATPase, phospholamban) were measured by Western blot analysis in nonfailing human myocardium (n = 7) and in end-stage failing myocardium due to dilated cardiomyopathy (n = 14). The levels of the ryanodine receptor, calsequestrin, and calreticulin were not significantly different in nonfailing and failing human myocardium. Phospholamban protein levels (pentameric form) normalized per total protein were decreased by 18% in the failing myocardium (P < .05). However, phospholamban protein levels were not significantly different in failing and nonfailing myocardium when normalization was performed per calsequestrin. Protein levels of SR calcium ATPase, normalized per total protein or per calsequestrin, were decreased by 41% (P < .001) or 33% (P < .05), respectively, in the failing myocardium. Furthermore, SR calcium ATPase was decreased relative to ryanodine receptor by 37% (P < .05) and relative to phospholamban by 28% (P < .05). CONCLUSIONS Levels of SR proteins involved in calcium binding and release are unchanged in failing dilated cardiomyopathy. In contrast, protein levels of calcium ATPase involved in SR calcium uptake are reduced in the failing myocardium. Moreover, SR calcium ATPase is decreased relative to its inhibitory protein, phospholamban.(ABSTRACT TRUNCATED AT 250 WORDS)

Relationship Between Na+-Ca2+–Exchanger Protein Levels and Diastolic Function of Failing Human Myocardium

BACKGROUND In the failing human heart, sarcoplasmic reticulum (SR) calcium handling is impaired, and therefore, calcium elimination and diastolic function may depend on the expression of sarcolemmal Na+-Ca2+ exchanger. METHODS AND RESULTS Force-frequency relations were studied in ventricular muscle strip preparations from failing human hearts (n=29). Protein levels of Na+-Ca2+ exchanger and SR Ca2+-ATPase were measured in the same hearts. Hearts were divided into 3 groups by discriminant analysis according to the behavior of diastolic function when stimulation rate of muscle strips was increased from 30 to 180 min-1. At 180 compared with 30 min-1, diastolic force was increased by 160%, maximum rate of force decline was decreased by 46%, and relaxation time was unchanged in group III. In contrast, in group I, diastolic force and maximum rate of force decline did not change, and relaxation time decreased by 20%. Na+-Ca2+ exchanger was 66% higher in group I than in group III. Na+-Ca2+ exchanger was inversely correlated with the frequency-dependent rise of diastolic force when stimulation rate was increased (r=-0.74; P<0.001). Compared with nonfailing human hearts (n=6), SR Ca2+-ATPase was decreased and Na+-Ca2+ exchanger unchanged in group III, whereas Na+-Ca2+ exchanger was increased and SR Ca2+-ATPase unchanged in group I. Results with group II hearts were between those of group I and group III hearts. CONCLUSIONS By discriminating failing human hearts according to their diastolic function, we identified different phenotypes. Disturbed diastolic function occurs in hearts with decreased SR Ca2+-ATPase and unchanged Na+-Ca2+ exchanger, whereas increased expression of the Na+-Ca2+ exchanger is associated with preserved diastolic function.

MitraClip® therapy in patients with end-stage systolic heart failure.

To assess the feasibility, short‐term durability and clinical outcomes of MitraClip® therapy for mitral regurgitation (MR) in patients with end‐stage heart failure and a severely reduced left ventricular (LV) ejection fraction.

Left atrial appendage occlusion for stroke prevention in atrial fibrillation: multicentre experience with the AMPLATZER Cardiac Plug.

AIMS To investigate the safety, feasibility, and efficacy of left atrial appendage occlusion (LAAO) with the AMPLATZER Cardiac Plug (ACP) for stroke prevention in patients with atrial fibrillation (AF). METHODS AND RESULTS Data from consecutive patients treated in 22 centres were collected. A total of 1,047 patients were included in the study. Procedural success was 97.3%. There were 52 (4.97%) periprocedural major adverse events. Follow-up was complete in 1,001/1,019 (98.2%) of successfully implanted patients (average 13 months, total 1,349 patient-years). One-year all-cause mortality was 4.2%. No death at follow-up was reported as device-related. There were nine strokes (0.9%) and nine transient ischaemic attacks (0.9%) during follow-up. The annual rate of systemic thromboembolism was 2.3% (31/1,349 patient-years), which is a 59% risk reduction. There were 15 major bleedings (1.5%) during follow-up. The annual rate of major bleeding was 2.1% (28/1,349 patient-years), which is a 61% risk reduction. Patients with single LAAO on aspirin monotherapy or no therapy and longer follow-up had fewer cerebral and fewer bleeding events. CONCLUSIONS In this multicentre study, LAAO with the ACP showed high procedural success and a favourable outcome for the prevention of AF-related thromboembolism. Modification in antithrombotic therapy after LAAO may result in reduction of bleeding events.

Correction of Mitral Regurgitation in Nonresponders to Cardiac Resynchronization Therapy by MitraClip Improves Symptoms and Promotes Reverse Remodeling

OBJECTIVES This study evaluated the safety, efficacy, and effect of MitraClip treatment on symptoms and left ventricular (LV) remodeling in nonresponders to cardiac resynchronization therapy (CRT). BACKGROUND Moderate to severe functional mitral regurgitation (FMR) frequently persists after CRT, contributing to reduced or no response to CRT. Percutaneous repair with the MitraClip has been proposed as an additional therapeutic option in select patients with significant FMR. METHODS Fifty-one severely symptomatic CRT nonresponders with significant FMR (grade ≥2, 100%) underwent MitraClip treatment. Changes in New York Heart Association functional class, degree of FMR, LV ejection fraction (EF), and LV end-diastolic/end-systolic volumes (EDV/ESV) before and after (3, 6, and 12 months) MitraClip implantation were recorded. Mortality data, including cause of death, were collected. RESULTS MC treatment was feasible in all patients (49% 1 clip, 46% 2 clips). There were 2 periprocedural deaths. Median follow-up was 14 months (25th to 75th percentile: 8 to 17 months). New York Heart Association functional class improved acutely at discharge (73%) and continued to improve progressively during follow-up (regression model, p < 0.001). The proportion of patients with significant residual FMR (grade ≥2) progressively decreased during follow-up (regression model, p < 0.001). Reverse LV remodeling and improved LVEF were detected at 6 months, with further improvement at 12 months (regression model, p = 0.001, p = 0.008, and p = 0.031 for ESV, EDV, and LVEF, respectively). Overall 30-day mortality was 4.2%. Overall mortality during follow-up was 19.9 per 100 person-years (95% confidence interval: 10.3 to 38.3). Nonsurvivors had more compromised clinical baseline conditions, longer QRS duration, and a more dilated heart. CONCLUSIONS FMR treatment with the MitraClip in CRT nonresponders was feasible, safe, and demonstrated improved functional class, increased LVEF, and reduced ventricular volumes in about 70% of these study patients.

MitraClip therapy in daily clinical practice: initial results from the German transcatheter mitral valve interventions (TRAMI) registry

A substantial percentage of patients with mitral regurgitation (MR) in need of mitral valve repair are currently considered not suitable for conventional surgery. In Germany, the largest cohort of patients studied to date has been treated using a percutaneous, catheter‐based approach. We report the acute outcomes of patients enrolled in the investigator‐initiated German transcatheter mitral valve interventions (TRAMI) registry.

One-year outcomes and predictors of mortality after MitraClip therapy in contemporary clinical practice: results from the German transcatheter mitral valve interventions registry

Abstract Aims The transcatheter mitral valve interventions (TRAMI) registry was established in order to assess safety and efficacy of catheter-based mitral valve interventional techniques in Germany, and prospectively enrolled 828 MitraClip patients (median age 76 years, median log. EuroSCORE I 20.0%) between August 2010 and July 2013. We present the 1-year outcome in this MitraClip cohort—which is the largest published to date. Methods and results Seven forty-nine patients (90.5%) were available for 1-year follow-up and included in the following analyses. Mortality, major adverse cardiovascular event rates, and New York Heart Association (NYHA) classes were recorded. Predictors of 1-year mortality were identified by multivariate analysis using a Cox regression model with stepwise forward selection. The 1-year mortality was 20.3%. At 1 year, 63.3% of TRAMI patients pertained to NYHA functional classes I or II (compared with 11.0% at baseline), and self-rated health status (on EuroQuol visual analogue scale) also improved significantly by 10 points. Importantly, a significant proportion of patients regained the complete independence in self-care after MitraClip implantation (independence in 74.0 vs. 58.6% at baseline, P = 0.005). Predictors of 1-year mortality were NYHA class IV (hazard ratio, HR 1.62, P = 0.02), anaemia (HR 2.44, P = 0.02), previous aortic valve intervention (HR 2.12, P = 0.002), serum creatinine ≥1.5 mg/dL (HR 1.77, P = 0.002), peripheral artery disease (HR 2.12, P = 0.0003), left ventricular ejection fraction <30% (HR 1.58, P = 0.01), severe tricuspid regurgitation (HR 1.84, P = 0.003), and procedural failure (defined as operator-reported failure, conversion to surgery, failure of clip placement, or residual post-procedural severe mitral regurgitation) (HR 4.36, P < 0.0001). Conclusions Treatment of significant MR with MitraClip resulted in significant clinical improvements in a high proportion of TRAMI patients after 12 months. In the TRAMI cohort, the failure of procedural success exhibited the highest hazard ratio concerning the prediction of 1-year mortality.

Impaired Contractile Performance of Cultured Rabbit Ventricular Myocytes After Adenoviral Gene Transfer of Na+-Ca2+ Exchanger

Na+-Ca2+ exchanger (NCX) gene expression is increased in the failing human heart. We investigated the hypothesis that upregulation of NCX can induce depressed contractile performance. Overexpression of NCX was achieved in isolated rabbit ventricular myocytes through adenoviral gene transfer (Ad-NCX). After 48 hours, immunoblots revealed a virus dose-dependent increase in NCX protein. Adenoviral &bgr;-galactosidase transfection served as a control. The fractional shortening (FS) of electrically stimulated myocytes was analyzed. At 60 min−1, FS was depressed by 15.6% in the Ad-NCX group (n=143) versus the control group (n=163, P <0.05). Analysis of the shortening-frequency relationship showed a steady increase in FS in the control myocytes (n=26) from 0.027±0.002 at 30 min−1 to 0.037±0.002 at 120 min−1 (P <0.05 versus 30 min−1) and to 0.040±0.002 at 180 min−1 (P <0.05 versus 30 min−1). Frequency potentiation of shortening was blunted in NCX-transfected myocytes (n=27). The FS was 0.024±0.002 at 30 min−1, 0.029±0.002 at 120 min−1 (P <0.05 versus 30 min−1, P <0.05 versus control), and 0.026±0.002 at 180 min−1 (NS versus 30 min−1, P <0.05 versus control). Caffeine contractures, which indicate sarcoplasmic reticulum Ca2+ load, were significantly reduced at 120 min−1 in NCX-transfected cells. An analysis of postrest behavior showed a decay of FS with longer rest intervals in control cells. Rest decay was significantly higher in the Ad-NCX group; after 120 seconds of rest, FS was 78±4% in control and 65±3% in the Ad-NCX group (P <0.05) relative to steady-state FS before rest (100%). In conclusion, the overexpression of NCX in rabbit cardiomyocytes results in the depression of contractile function. This supports the hypothesis that upregulation of NCX can result in systolic myocardial failure.

Acute outcomes after MitraClip therapy in highly aged patients: results from the German TRAnscatheter Mitral valve Interventions (TRAMI) Registry.

AIMS The influence of age on baseline demographics and outcomes of patients selected for MitraClip has not been previously investigated. METHODS AND RESULTS Baseline demographics and acute outcomes in 1,064 patients from the German TRAMI registry were stratified by age (525 patients ≥76 years and 539 patients <76 years). In elderly patients, logistic EuroSCORE was higher (25[15-40]% vs. 18[10-31]%, p<0.0001) and the proportion of women was greater (47.2% vs. 29.3%, p<0.0001). Elderly patients were more likely to have preserved left ventricular ejection fraction >50% (40.1% vs. 21.8%, p<0.0001) and degenerative mitral regurgitation (DMR, 35.3% vs. 25.6%, p<0.01). Age was the most frequent reason for non-surgical treatment in the elderly (69.4% vs. 36.1%, p<0.0001). The intrahospital MACCE (death, myocardial infarction, stroke) was low in both groups (3.5% vs. 3.4%, p=0.93) and the proportion of non-severe mitral regurgitation at discharge was similar (95.8% vs. 96.4%, p=0.73). A logistic regression model did not reveal any significant impact of age on acute efficacy and safety of MitraClip therapy. In both groups, the majority of patients were discharged home (81.8% vs. 86.2%, p=0.06). CONCLUSIONS Elderly and younger patients have similar benefits from MitraClip therapy. Age was the most frequent cause for denying surgery in elderly patients.

Impact of the learning curve on outcomes after percutaneous mitral valve repair with MitraClip® and lessons learned after the first 75 consecutive patients

Mitral valve regurgitation plays a significant role in the aetiology and course of heart failure. We investigated the impact of the learning curve on outcomes after percutaneous mitral valve repair with MitraClip.