Left ventricular myocardial strain responding to chronic pressure overload in patients with resistant hypertension evaluated by feature-tracking CMR.

OBJECTIVES: The study aimed to investigate the alterations of myocardial deformation responding to long-standing pressure overload and the effects of focal myocardial fibrosis using feature-tracking cardiac magnetic resonance (FT-CMR) in patients with resistant hypertension (RH). METHODS: Consecutive RH patients were prospectively recruited and underwent CMR at a single institution. FT-CMR analyses based on cine images were applied to measure left ventricular (LV) peak systolic global longitudinal (GLS), radial (GRS), and circumferential strain (GCS). Functional and morphological CMR variables, and late gadolinium enhancement (LGE) imaging were also obtained. RESULTS: A total of 50 RH patients (63 ± 12 years, 32 men) and 18 normotensive controls (57 ± 8 years, 12 men) were studied. RH patients had a higher average systolic blood pressure than controls (166 ± 21 mmHg vs. 116 ± 8 mmHg, p < 0.001) with the intake of 5 ± 1 antihypertensive drugs. RH patients showed increased LV mass index (78 ± 15 g/m2 vs. 61 ± 9 g/m2, p < 0.001), decreased GLS (- 16 ± 3% vs. - 19 ± 2%, p = 0.001) and GRS (41 ± 12% vs. 48 ± 8%, p = 0.037), and GCS was reduced by trend (- 17 ± 4% vs. - 19 ± 4%, p = 0.078). Twenty-one (42%) RH patients demonstrated a LV focal myocardial fibrosis (LGE +). LGE + RH patients had higher LV mass index (85 ± 14 g/m2 vs. 73 ± 15 g/m2, p = 0.007) and attenuated GRS (37 ± 12% vs. 44 ± 12%, p = 0.048) compared to LGE - RH patients, whereas GLS (p = 0.146) and GCS (p = 0.961) were similar. CONCLUSION: Attenuation of LV GLS and GRS, and GCS decline by tendency, might be adaptative changes responding to chronic pressure overload. There is a high incidence of focal myocardial fibrosis in RH patients, which is associated with reduced LV GRS. CLINICAL RELEVANCE STATEMENT: Feature-tracking CMR-derived myocardial strain offers insights into the influence of long-standing pressure overload and of a myocardial fibrotic process on cardiac deformation in patients with resistant hypertension. KEY POINTS: • Variations of left ventricular strain are attributable to the degree of myocardial impairment in resistant hypertensive patients. • Focal myocardial fibrosis of the left ventricle is associated with attenuated global radial strain. • Feature-tracking CMR provides additional information on the attenuation of myocardial deformation responding to long-standing high blood pressure.

Limits of and Complications after Embolization of the Hepatic Artery and Portal Vein to Induce Segmental Hypertrophy of the Liver: A Large Mini-Pig Study.

BACKGROUND: The aim of this study was to compare arterial embolization (AE) with portal vein embolization (PVE) for the induction of segmental hypertrophy regarding procedural efficacy, safety and outcome. METHODS: A total of 29 mini pigs were subjected to PVE, AE or assigned to the sham (SO) group. Correspondingly, 75% of the hepatic artery or portal vein branches were embolized. Growth and atrophy of the liver lobes, calculating the liver-to-body weight index (LBWI), laboratory data, arteriography, portography, Doppler ultrasound (US) and histopathology were analyzed. RESULTS: After PVE, 2 animals had to be excluded due to technical problems. After AE, 4 animals had to be excluded because of technical problems and early sacrifice. Postprocedural US demonstrated effective AE and PVE of the respective lobes. Four weeks after PVE, portography showed a slow refilling of the embolized lobe by collateral portal venous vessels. Four weeks after AE, arteriography revealed a slight revascularization of the embolized lobes by arterial neovascularization. Segmental AE led to extensive necrotic and inflammatory alterations in the liver and bile duct parenchyma. Significant hypertrophy of the non-embolized lobe was only noted in the PVE group (LBWI: 0.91 ± 0.28%; p = 0.001). There was no increase in the non-embolized lobe in the AE (LBWI: 0.45 ± 0.087%) and SO group (LBWI: 0.45 ± 0.13%). CONCLUSION: PVE is safe and effective to induce segmental hypertrophy. Portal reperfusion by collateral vessels may limit hypertrophy. AE did not increase the segmental hepatic volume but carries the risk of extensive necrotic inflammatory damage.

Transcapsular arterial neovascularization of liver transplants increases the risk of intraoperative bleeding during retransplantation.

Arterial neovascularization of liver grafts can be a source of significant blood loss during retransplantation. This study evaluated the effect of transcapsular arterial neovascularization on intraoperative blood loss during retransplantation and long-term follow-up. Eleven consecutive patients with transcapsular arterial neovascularization (seven male, four female; nine children, two adults; mean age 12.3 ± 16.3 years) and the same number of matched control patients were analysed. Blood loss was calculated based on transfusion requirements. The volume of transfused units of red blood cells per kilogram bodyweight until hepatectomy and during the entire procedure was significantly higher in patients with neovascularization than in control patients (0.32 ± 0.21 vs. 0.14 ± 0.11, and 0.94 ± 0.83 vs. 0.36 ± 0.38 respectively; P-values 0.027). Neovascularization was associated with extensive intra-abdominal adhesions and a longer operating time until hepatectomy (175.6 ± 52.1 min vs. 124.3 ± 34.9 min, P-value 0.015). Postoperative revisions were performed more frequently in patients with neovessels. Graft survival did not differ between groups. Assessment for transcapsular arterial neovascularization should be included in preoperative Doppler ultrasound protocols to identify patients at risk of a complicated intra- and postoperative course in case of retransplantation.

Follow-up of radiologically totally implanted central venous access ports of the upper arm: long-term complications in 127,750 catheter-days.

OBJECTIVE: The purpose of this article is to retrospectively evaluate radiologically totally implanted central venous access ports (VAPs) of the upper arm in terms of safety, technical feasibility, and device-related complications. MATERIALS AND METHODS: Five hundred seven consecutive patients (mean [± SD] age, 59.2 ± 11.4 years) who received a totally implanted central VAP between January 2005 and July 2010 were included. The insertion procedure was performed in an interventional radiology suite using the Seldinger technique. Neither antibiotic prophylaxis nor long-term anticoagulation was administered. RESULTS: In 507 patients, a total of 523 devices were implanted. Of these 523 procedures, 512 complete datasets were available during follow-up. The primary technical success rate was 99.04%. All procedures were completed without major complications. During follow-up and with a total number of 127,750 days of totally implanted central VAP implantation (248 ± 279 days/patient; range, 1-1687 days/patient), 50 devices had to be revised because of complications (9.8%). Complications occurred at a mean of 114 ± 183 days (range, 1-1113 days) after placement. Early complications were noted in 21 of 512 cases (4.1%), and late complications were noted in 29 of 512 cases (5.7%). Complications were as follows: local infections, 4.9% (25/512); systemic infections, 0.4% (2/512); venous thrombosis, 1.6% (8/512); paralysis of the median nerve, 0.6% (3/512); skin dehiscence at the port site, 0.2% (1/512); and mechanical problems including catheter line displacement, port hub rotation, and catheter fracture, 2.1% (11/512). CONCLUSION: Radiologic placement of a totally implanted central VAP is a safe procedure with a low rate of both early and late device-related complications. The method is effective for delivery of chemotherapy, parenteral nutrition, and frequent IV medication.

The transhepatic endotoxin gradient is present despite liver cirrhosis and is attenuated after transjugular portosystemic shunt (TIPS).

BACKGROUND: Translocation of gut-derived bacterial products such as endotoxin is a major problem in liver cirrhosis. METHODS: To assess the hepatic clearance of bacterial products in individuals with cirrhosis, we tested concentrations of Gram-negative bacterial lipopolysaccharide (LPS), LPS-binding protein (LBP), and the precursor of nitric oxide (NO), L-arginine, in a cohort of 8 stable patients with liver cirrhosis before and after elective transjugular portosystemic shunt (TIPS) implantation, including central venous, hepatic venous, and portal venous measurements. RESULTS: Using an adapted LPS assay, we detected high portal venous LPS concentrations (mean 1743 ± 819 pg/mL). High concentrations of LPS were detectable in the central venous blood (931 ± 551 pg/mL), as expected in persons with cirrhosis. The transhepatic LPS gradient was found to be 438 ± 287 pg/mL, and 25 ± 12% of portal LPS was cleared by the cirrhotic liver. After TIPS, central venous LPS concentrations increased in the hepatic and central veins, indicating shunting of LPS with the portal blood through the stent. This paralleled a systemic increase of L-arginine, whereas the NO synthase inhibitor asymmetric dimethylarginine (ADMA) remained unchanged, suggesting that bacterial translocation may contribute to the pathogenesis of circulatory dysfunction post-TIPS. CONCLUSIONS: This study provides quantitative estimates of the role of the liver in the pathophysiology of bacterial translocation. The data indicate that the cirrhotic liver retains the capacity for clearance of bacterial endotoxin from the portal venous blood and that TIPS implantation attenuates this clearance. Thus, increased endotoxin concentrations in the systemic circulation provide a possible link to the increased encephalopathy in TIPS patients.

Comparison of whole body MR angiography at 1.5 and 3 Tesla in patients with hereditary hyperlipidemia.

BACKGROUND: Patients suffering from hereditary hyperlipidemia have a high risk for premature cardiovascular disease and death as a consequence of accelerated atherosclerosis. PURPOSE: To prospectively and intra-individually compare image quality and detectability of stenoses in contrast enhanced whole-body MRA (WBMRA) at 1.5 and 3 Tesla (T) in patients with hereditary hyperlipidemia. MATERIAL AND METHODS: Twenty-seven patients with hereditary hyperlipidemia received a 1.5 and 3 T gadopentetate dimeglumine contrast-enhanced WBMRA. Twenty-three defined arterial segments were analyzed regarding depiction of target vessels and image quality according to a 5-point-scale ('not evaluable' to 'excellent'). Wilcoxon matched pair test was performed for comparison. Forty-three defined arterial segments were analyzed for the degree of stenosis (0%, 1-49%, 50-99% and 100%) as well as vessel alterations such as aneurysms. Chi-square test was performed for comparison. RESULTS: 1.5 T and 3 T scans yielded WBMRA with diagnostic quality in all patients. In seven of 23 arterial segments (30.4%) image quality was rated significantly higher at 3 T, whereas there was no significant difference in the remaining 16 segments between WBMRA at 1.5 T and 3 T. All relevant stenoses (n = 5), occlusions (n = 6), and aneurysms (n = 3) were evaluated similarly at both field strengths. CONCLUSION: WBMRA can be performed at 1.5 T and 3 T with diagnostic image quality. Image quality was significantly higher at 3 T than at 1.5 T in only 30.4% of the arterial segments. In order to effectively take advantage of the higher field strength, further optimization of sequence parameters and injection protocols for WBMRA at 3 T is necessary.

Interactive real-time mapping and catheter ablation of the cavotricuspid isthmus guided by magnetic resonance imaging in a porcine model.

AIMS: We investigated the feasibility of real-time magnetic resonance imaging (RTMRI) guided ablation of the cavotricuspid isthmus (CTI) by using a MRI-compatible ablation catheter. METHODS AND RESULTS: Cavotricuspid isthmus ablation was performed in an interventional RTMRI suite by using a novel 7 French, steerable, non-ferromagnetic ablation catheter in a porcine in vivo model (n = 20). The catheter was introduced and navigated by RTMRI visualization only. Catheter position and movement during manipulation were continuously visualized during the entire intervention. Two porcine prematurely died due to VT/VF. Anatomical completion of the CTI ablation line could be achieved after a mean of 6.3+/-3 RF pulses (RF energy: 1807+/-1016.4 Ws/RF pulse, temperature: 55.9+/-5.9 degrees C) in n = 18 animals. In 15 of 18 procedures (83.3%) a complete CTI block was proven by conventional mapping in the electrophysiological (EP) lab. CONCLUSION: Completely non-fluoroscopic ablation guided by RTMRI using a steerable and non-ferromagnetic catheter is a promising novel technology in interventional electrophysiology.

Effect of renal denervation procedure on left ventricular mass, myocardial strain and diastolic function by CMR on a 12-month follow-up.

PURPOSE: To investigate the effects of renal denervation (RDN) on left ventricular (LV) mass, myocardial strain and diastolic function in patients with treatment-resistant arterial hypertension by cardiac magnet resonance imaging on a 12-month follow-up. MATERIALS AND METHODS: Sixteen patients (38% female) were examined before and 12 months after RDN. LV morphology and strain were analyzed. Diastolic function was determined by early (EPFR) and atrial peak filling rates (APFR) derived from differential volume-time-curve analysis. Clinical visits included 24-h ambulant blood pressure monitoring (ABPM). RESULTS: Twelve months after RDN LV mass decreased from 80 ± 21 g/m2 to 74 ± 20 g/m2 (P < 0.05). Global radial (35 ± 12% vs. 41 ± 10%, P < 0.05) and longitudinal strain improved (- 15 ± 4% vs. - 17 ± 3%, P < 0.05). Global circumferential strain (- 16 ± 5% vs. - 18 ± 4%, P = 0.12) remained unchanged. The parameter of diastolic LV function PFRR (EPFR/APFR) improved following RDN (0.9 ± 0.4 vs. 1.1 ± 0.5, P < 0.05). Individual changes of LV mass were associated with an increase of EPFR (r = - 0.54, P < 0.05) and a reduction of APFR by trend (r = 0.45, P = 0.08). Systolic ABPM showed a decrease by trend (152 mmHg vs. 148 mmHg, P = 0.08). CONCLUSIONS: After RDN we observed a reduction of LV mass, improvement of global strain and diastolic function.

Catheter ablation of paroxysmal atrial fibrillation improves cardiac function: a prospective study on the impact of atrial fibrillation ablation on left ventricular function assessed by magnetic resonance imaging.

AIMS: Beneficial effects of atrial fibrillation (AF) ablation have been demonstrated in patients with congestive heart failure (CHF) and significantly impaired left ventricular ejection fraction (LVEF). However, the impact of pulmonary vein isolation (PVI) on cardiac function in patients with paroxysmal AF and impaired LVEF remains under discussion. This study aimed to evaluate the impact of PVI for paroxysmal AF on cardiac function in patients with impaired LVEF using cardiac magnetic resonance imaging (CMRI). METHODS AND RESULTS: A total number of 70 patients with paroxysmal AF and episodes < or = 24 h were scanned on a 1.5-T-CMRI before and 6 months after PVI during sinus rhythm. End-diastolic volume, end-systolic volume, and LVEF were determined by epicardial and endocardial measurements. Patients were categorized into two groups regarding cardiac function as assessed by CMRI: group 1 patients (n = 18) with an LVEF < 50% and patients with an LVEF > 50% (group 2, n = 52). Group 1 patients demonstrated a significant lower success rate than patients of group 2 after a follow-up of 152 +/- 40 days (50 vs. 73%, P < 0.05). Cardiac magnetic resonance imaging in group 1 patients demonstrated a significant improvement in cardiac function after AF ablation (41 +/- 6 vs. 51 +/- 12%, P = 0.004), whereas group 2 patients did not show significant differences (60 +/- 6 vs. 59 +/- 9%, P = 0.22) after a 6 months follow-up. CONCLUSION: Pulmonary vein isolation improves cardiac function in patients with paroxysmal AF and impaired LVEF. These data suggest that an impaired LV function can be partially attributed to AF with short-lasting paroxysms.

Bile resistance of coated transjugular intrahepatic portosystemic shunt stents in a flow-model.

PURPOSE: We sought to test the bile resistance of transjugular intrahepatic portosystemic shunt (TIPS) stents with 3 different coatings. MATERIALS AND METHODS: Three stents with different coating materials (monolayer polyethylene terephthalate [PETP], monolayer polytetrafluoroethylene [PTFE], and double layer [PTFE]) were tested in a flow model. After testing the sealing of the system with isotonic saline solution, fresh human bile was circulated. Constant pressure was 50 cm H2O. Bile resistance of the stent membranes was analyzed. RESULTS: Two of the 3 stents proved completely resistant to water. Only the PETP stent was resistant to bile. The PTFE-coated stents were not bile resistant. CONCLUSION: The bile resistance of coated TIPS stents and, thus, the dependency of TIPS shunt patency is called into question. The stent with the reported superior patency rates does not show experimental bile resistance.

Successful resection of a symptomatic right ventricular lipoma.

We report the case of a 31-year-old woman with a 4-year history of recurrent palpitations, presenting with an increased frequency of paroxysms caused by ventricular tachycardias during pregnancy. A cardiac tumor of unknown origin infiltrating the right ventricle was diagnosed. Three weeks after prophylactic abrasion the tumor was totally excised with the use of cardiopulmonary bypass including restoration of the right ventricular wall and the tricuspid valve. Histology confirmed diagnosis of a benign cardiac lipoma. The postoperative course was uneventful and the patient was discharged 7 days after surgery. There was no episode of ventricular tachycardias during the 6-month follow-up.

Diagnostic accuracy of state-of-the-art MDCT scanners without gantry tilt in patients with oral and oropharyngeal cancer.

PURPOSE: Current CT-protocols for staging oral and oropharyngeal cancer include primary transversal slices and secondary tilted slices to avoid artifact-producing regions of dental metalwork. Some of the latest MDCT scanners do not allow gantry tilt. Hence, we assessed the relevance of secondary tilted slices in tumor staging. MATERIALS AND METHODS: Scans of a tiltable 64-row MDCT-scanner of 82 patients with oral or oropharyngeal cancer were retrospectively and independently evaluated twice by three readers: once using the primary transversal scans only, and once taking the transversal and secondary tilted scans into account. Tumor diameters and TN-stage were determined with both methods. Artifacts on transversal scans were analyzed using a 3-point-ranking-scale. RESULTS: Image quality was impaired by severe artifacts in 24% of transversal slices of the oral cavity and in 12% of the oropharynx. The three readers detected an average of 57.7 ± 2.1 of 82 tumors (70%) on transversal CT slices. An average of 6.3 ± 0.6 more tumors (8%) were detected when transversal studies were evaluated in conjunction with secondary tilted slices, leading to a significantly (p=0.0156-0.0313) increased average detection rate of 64.0 ± 2.0 tumors (78%). Moreover, secondary tilted slices led to a correction of underestimated tumor stages in up to six patients (7.3%). CONCLUSION: Tilted slices that avoid artifact-producing regions of dental metalwork significantly improve the reader's sensitivity and are of incremental value for staging of oral and oropharyngeal cancers.

Multicontrast-weighted magnetic resonance imaging of atherosclerotic plaques at 3.0 and 1.5 Tesla: ex-vivo comparison with histopathologic correlation.

The purpose was to analyze magnetic resonance (MR) plaque imaging at 3.0 Tesla and 1.5 Tesla in correlation with histopathology. MR imaging (MRI) of the abdominal aorta and femoral artery was performed on seven corpses using T1-weighted, T2-weighted, and PD-weighted sequences at 3.0 and 1.5 Tesla. Cross-sectional images at the branching of the inferior mesenteric artery and the profunda femoris were rated with respect to image quality. Corresponding cross sections of the imaged vessels were obtained at autopsy. The atherosclerotic plaques in the histological slides and MR images were classified according to the American Heart Association (AHA) and analyzed for differences. MRI at 3.0 Tesla offered superior depiction of arterial wall composition in all contrast weightings, rated best for T2-weighted images. Comparing for field strength, the highest differences were observed in T1-weighted and T2-weighted techniques (both P< or =0.001), with still significant differences in PD-weighted sequence (P< or =0.005). The majority of plaques were histologically classified as calcified plaques. In up to 21% of the cases, MRI at both field strengths detected signal loss characteristic of calcification although calcified plaque was absent in histology. MRI at 3.0 Tesla offers superior plaque imaging quality compared with 1.5 Tesla, but further work is necessary to determine whether this translates in superior diagnostic accuracy.

Evaluation of the influence of acquisition and reconstruction parameters for 16-row multidetector CT on coronary calcium scoring using a stationary and dynamic cardiac phantom.

A calcium-scoring phantom with hydroxyapatite-filled cylindrical holes (0.5 to 4 mm) was used. High-resolution scans were performed for an accuracy baseline. The phantom was mounted to a moving heart phantom. Non-moving data with the implementation of an ECG-signal were acquired for different pitches (0.2/0.3), heart rates (60/80/95 bpm) and collimations (16 x 0.75/16 x 1.5 mm). Images were reconstructed with a cone-beam multi-cycle algorithm at a standard thickness/increment of 3 mm/1.5 mm and the thinnest possible thickness (0.8/0.4 and 2/1). Subsequently, ECG-gated moving calcium-scoring phantom data were acquired. The calcium volume and Agatston score were measured. The temporal resolution and reconstruction cycles were calculated. High-resolution scans determine the calcium volume with a high accuracy (mean overestimation, 0.8%). In the non-moving measurements, the volume underestimation ranged from about 6% (16 x 0.75 mm; 0.8/0.4 mm) to nearly 25% (16 x 1.5 mm; 3/1.5 mm). Moving scans showed increased measurement errors depending on the reconstructed RR interval, collimation, pitch, heart rate and gantry rotation time. Also, a correlation with the temporal resolution could be found. The reliability of calcium-scoring results can be improved with the use of a narrower collimation, a lower pitch and the reconstruction of thinner images, resulting in higher patient doses. The choice of the correct cardiac phase within the RR interval is essential to minimize measurement errors.