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Risk and Fate of Cerebral Embolism After Transfemoral Aortic Valve Implantation : A Prospective Pilot Study With Diffusion-Weighted Magnetic Resonance Imaging

OBJECTIVES The aim of this study was prospective investigation of silent and clinically apparent cerebral embolic events and neurological impairment after transfemoral aortic valve implantation (TAVI). BACKGROUND TAVI is a novel therapeutic approach for multimorbid patients with severe aortic stenosis. We investigated peri-interventional cerebral embolism with diffusion-weighted magnetic resonance imaging (DW-MRI) and its relationship to clinical and serologic parameters of brain injury. METHODS Cerebral DW-MRI was performed before, directly, and 3 months after TAVI with the current third-generation self-expanding CoreValve (Medtronic, Minneapolis, Minnesota) prosthesis. At the timepoints of the serial MRI studies, focal neurological impairment was assessed according to the National Institutes of Health Stroke Scale (NIHSS), and serum concentration of neuron-specific enolase (NSE), a marker of the volume of brain tissue involved in an ischemic event, were determined. RESULTS Thirty patients were enrolled; 22 completed the imaging protocol. Three patients (10%) had new neurological findings after TAVI, of whom only 1 (3.6%) had a permanent neurological impairment. Of the 22 TAVI patients with complete imaging data, 16 (72.7%) had 75 new cerebral lesions after TAVI presumed to be embolic. The NIHSS and NSE were not correlated with DW-MRI lesions. CONCLUSIONS The incidence of clinically silent peri-interventional cerebral embolic lesions after TAVI is high. However, in this cohort of 30 patients, the incidence of persistent neurological impairment was low. (Incidence and Severity of Silent and Apparent Cerebral Embolism After Conventional and Minimal-invasive Transfemoral Aortic Valve Replacement; NCT00883285).

Incidence and predictors of silent cerebral embolism during pulmonary vein catheter ablation for atrial fibrillation

AIMS Left atrial catheter ablation of the pulmonary veins (PV) has evolved as an important therapeutic option for the treatment of atrial fibrillation (AF). We aimed to investigate the incidence and predictors of silent cerebral embolism associated with PV catheter ablation, detected by diffusion-weighted magnetic resonance imaging (DW-MRI). METHODS AND RESULTS We performed a prospective analysis of 53 consecutive patients with persistent or paroxysmal AF that underwent PV ablation and post-procedural cerebral MRI 1 day after lasso catheter-guided ostial PV ablation. Patients were analysed for possible demographical, medical, echocardiographical, and procedural predictors of embolic events. A mean of 3.5 +/- 0.5 PVs were ablated per patient. In six patients, DW-MRI depicted new clinically silent microembolism after PV ablation (11%). The number of ineffective medical antiarrhythmic agents prior to ablation procedure was significantly higher in the embolism group (3.3 +/- 0.5 vs. 2.2 +/- 1.4, P = 0.014). Coronary heart disease (CAD) was more frequent in patients with cerebral embolisms (33 vs. 2%, P = 0.031); left ventricular volume (130 +/- 12 vs. 103 +/- 26 mL, P = 0.002), and septal wall thickness (13.0 +/- 1.4 vs. 7.9 +/- 4.8 mm, P = 0.025) were significantly increased. CONCLUSION This study shows a high incidence of silent micro-embolic events after PV ablation. CAD, left ventricular dilatation, and hypertrophy were potential predictors of this complication.

MRI scanning in patients with new and existing CapSureFix Novus 5076 pacemaker leads: Randomized trial results

BACKGROUND Magnetic resonance imaging (MRI) can be safely performed in patients with magnetic resonance (MR)-conditional pacemaker systems but remains relatively contraindicated with non-MR-conditional pacemaker systems. OBJECTIVE The purpose of this study was to evaluate the safety of MRI without positioning restrictions in patients with an MR-conditional pacemaker and currently a non-MR-conditional Medtronic CapSureFix Novus 5076 lead(s). METHODS The study randomized 266 patients in a 2:1 ratio to the MRI group (177 patients) or to the control group (89 patients). At 9-12 weeks postimplant, the MRI group underwent MRI at 1.5 T. Primary end points were MRI-related complication-free rate and noninferiority of the MRI group compared to the control group with regard to the proportion of patients with an increase of ≤0.5 V in right atrial (RA) and right ventricular (RV) pacing capture thresholds from immediately before MRI to 1-month after MRI. RESULTS No MRI-related complications occurred in 156 MRI-scanned patients who were followed through 1-month post-MRI. Differences in the proportion of patients with ≤0.5 V pacing capture threshold changes from pre-MRI to 1-month post-MRI were minimal between the groups for RA (proportions of 100% in both groups; a P value cannot be calculated) and RV leads (proportions of 99.3% in the MRI group and 100% in the control group; noninferiority test, P < .0001). Proportions of patients with acceptable sensing amplitude changes from pre-MRI to 1-month post-MRI were also similar between the 2 groups for RA and RV leads (noninferiority test, P < .0001 and P = .0004, respectively). No arrhythmias occurred during MRI. CONCLUSION MRI scans can be performed safely without positioning restrictions in patients with Medtronic CapSureFix Novus 5076 leads connected to an MR-conditional pacemaker.

Venous Obstruction in Asymptomatic Patients Undergoing First Implantation or Revision of a Cardiac Pacemaker or Implantable Cardioverter-Defibrillator: A Retrospective Single Center Analysis

PURPOSE To investigate the incidence and possible risk factors of upper deep vein obstruction in patients both prior to first cardiac device implantation and before device revision. MATERIALS AND METHODS Records of asymptomatic patients undergoing contrast venography prior to implantation or revision of a cardiac device from 09/2009 to 04/2012 were reviewed. Venograms were used to determine the presence of venous obstruction. Interrelations between the incidence of venous obstruction and patient- or device-related parameters were identified using Fishers exact test and univariate logistic regression. Multivariate logistic regression was used to identify independent predictors of venous obstruction. RESULTS 456 patients met the inclusion criteria (330 males, 126 females, 67.8  ±  12.9 years). 100 patients underwent first implantation, and 356 patients underwent device revision (mean time since implantation 82.5  ±  75.3 months). Venous obstruction was present in 11.0 % and 30.1 % before implantation and revision, respectively. Only presence of ventricular escape rhythm was significantly related to venous occlusion (p < 0.001) prior to first implantation. Prior to revision, significant predictors were male sex (p = 0.01), time since implantation (p < 0.0001), presence of escape rhythm (p = 0.02), compromised coagulation (p = 0.02), phenprocoumon (p = 0.005), and peripheral arterial disease (p = 0.01). CONCLUSION Although several risk factors could be identified, reliable prediction of venous obstruction was not possible. Therefore, we advocate performing venography in all patients prior to device revision or upgrade to avoid complications. In cases of first device implantation, the risks associated with venography should be weighed against the surprisingly high rate of deep upper vein obstruction.

Renal Denervation: Unde Venis et Quo Vadis?

OBJECTIVE AND METHODS Renal denervation is a minimally invasive, catheter-based option for the treatment of refractory hypertension. Indications and contraindications for renal denervation have been defined in an interdisciplinary manner. The efficacy and safety of the procedure were evaluated. RESULTS Currently, indication for renal denervation is limited to patients with primary hypertension and a systolic blood pressure of ≥ 160 mm Hg (or ≥ 150 mm Hg in diabetes type 2) despite optimal medical therapy with ≥ 3 different antihypertensive drugs. In this specific patient population, an average blood pressure reduction of 32/14 mmHg was observed in non-randomized/-controlled trials after renal denervation. These results were not confirmed in the first randomized controlled trial with a non-significantly superior blood pressure reduction of 14.1 ± 23.9 mm Hg compared to controls (-11.74 ± 25.94 mm Hg, difference -2.39 mm Hg p = 0.26 for superiority with a margin of 5 mm Hg) who underwent a sham procedure. CONCLUSION The efficacy and long-term effects of renal denervation need to be re-evaluated in light of the HTN3 study results. To date, renal denervation should not be performed outside of clinical trials. Future trials should also assess if renal denervation can be performed with sufficient safety and efficacy in patients with hypertension-associated diseases. The use of renal denervation as an alternative therapy (e. g. in patients with drug intolerance) can currently not be advocated. KEY POINTS The indication for renal denervation should be assessed in an interdisciplinary fashion and according to current guidelines with a special focus on ruling out secondary causes for arterial hypertension. 5 - 10 % of patients with hypertension suffer from refractory hypertension, but only about 1 % of patients meet the criteria for a renal denervation. Renal denervation leads to a significant decrease in office blood pressure; however, the impact on 24-hour blood pressure measurements remains unclear. In the first randomized controlled trial on renal denervation with a control group undergoing a sham procedure, blood pressure reduction failed to reach the anticipated level of superiority over best medical treatment. Periprocedural complications are rare, but long-term safety can currently not be appraised due to the limited data available.

Clinical Cardiac MR at 3.0 Tesla using parallel RF transmission with patient-adaptive local RF shimming: initial experience

Purpose: The use of high-field MRI scanners has introduced new challenges for cardiac imaging, associated with B1- and B0-field inhomogeneities. A dual – source RF transmission system may help reduce dielectric effects, thus improving image contrast and reducing local SAR peaks of cardiac TSE and SSFP sequences, thereby allowing a shorter minimum TR and TE of SSFP sequences. Thus, the aim of our study was to evaluate the impact of dual – source parallel RF transmission with patient adaptive RF-shimming on image quality and diagnostic confidence for routine clinical CMR using a 3.0 T dual – channel transmit whole – body MRI system. Materials and Methods: A clinical 3.0 T MRI system (Achieva 3.0T-TX, Philips Healthcare, Best, Netherlands), equipped with a dual-source RF transmission system was used. The effect of parallel RF transmission with patient adaptive B1 shimming (multi transmit=MTx) vs. conventional (single transmit=STx) RF transmission on SSFP sequences and TSE Black-Blood (TSE BB) sequences was evaluated. Images were analyzed independently by two experienced readers for homogeneity and diagnostic confidence on a 4-point grading-scale. Also, the presence of off-resonance artefacts in the SSFP images was rated on a 4-point grading scale. CNR between interventricular septum and blood pool was determined. Results: A total of 21 patients were included into the study. For both, TSE BB and SSFP -images, the use of MTx resulted in a significant improvement of image homogeneity and diagnostic confidence in the left and right ventricle. As a side effect, off-resonance artefacts were significantly reduced in the acquired SSFP images. Interrater agreement for all ratings was very good. The quantitative measurements revealed a significant increase of CNR in the RF shimmed images using MTx compared to the images acquired with STx.((BR))Conclusions: Patient adaptive local RF-shimming using parallel dual source RF-transmission significantly improves image homogeneity, diagnostic confidence and contrast of cardiac SSFP and TSE BB sequences.