D-dimers Are a Predictor of Clot Volume Inside Membrane Oxygenators During Extracorporeal Membrane Oxygenation.

Thrombosis inside the membrane oxygenator (MO) is a critical complication during venovenous extracorporeal membrane oxygenation (ECMO). The aim of this study was to prove if thrombotic clots manifest within the MO when D-dimer levels are elevated over a long-term period. Heparin-coated polymethylpentene MOs (n = 13) were exchanged due to high plasma D-dimer levels. Clot volume was calculated using multidetector computed tomography (MDCT). Coagulation parameters and MO function were analyzed before and after MO exchange. Before MO exchange, D-dimer levels increased significantly in each patient (11.5 [6.5-15.5] mg/L to 35.0 [34-35] mg/L, P ≤ 0.001). High levels of D-dimers were tolerated for 1 to 6 days. Additionally, fibrinogen concentration (n = 8) and platelet count decreased (n = 8). Within 48 h after exchange, D-dimer levels decreased significantly (n = 11, 12 [8-16] mg/L, P = 0.004). Fibrinogen concentration and platelet counts increased. Clots were found in all MOs in the inlet part of the device. Clot volume (16-106 cm(3) ) did not correlate with MO support time but increased significantly when high D-dimer levels were accepted for >2 days. An increase or high levels of D-dimers in absence of other explaining pathology during ECMO therapy reflected coagulation activity within the MO. Evidence of clots within the MO at high D-dimer levels and decrease after exchange underline the relevance of D-dimer testing during ECMO treatment. Besides, surveillance of MOs during ongoing ECMO therapy will help to predict clot formation, and to avoid system-induced coagulation disorders as well as critical situations.

Lone atrial fibrillation as a positive predictor of left atrial volume reduction following ablation of atrial fibrillation.

AIMS: We investigated predictors of left atrial volume reduction (LAVR) in patients with atrial fibrillation (AF) undergoing AF ablation. METHODS AND RESULTS: Sixty patients with AF underwent pulmonary vein isolation (PVI) using a pulmonary vein ablation catheter (PVAC). All patients underwent cardiac imaging by computed tomography or magnetic resonance imaging to determine LAV 1 day before and 140 ± 9.5 days after PVI. Clinical follow-up and 72 h electrocardiogram Holter monitoring were performed 1, 3, and 6 months after ablation, and every 6 months thereafter. Significant LAVR (n = 60, 89.3 ± 3.9 vs. 79.5 ± 3.6 mL, P < 0.0001) was shown for the study group as a whole, caused particularly by the subgroup of patients with ablation success (n = 45, 85.2 ± 4.6 vs. 72.5 ± 3.7 mL, P < 0.0001). In addition, significant LAVR was shown for patients with lone AF (n = 25, 88.8 ± 6.8 vs. 72.7 ± 5.3 mL, P < 0.0001), but not for patients with AF and concomitant arterial hypertension (n = 32, 89 ± 4.8 vs. 86.7 ± 5 mL, P = 0.3), coronary artery disease (n = 12, 91.6 ± 7.8 vs. 89.1 ± 7.8 mL, P = 0.26), or left ventricular hypertrophy (n = 10, 86.3 ± 5.5 vs. 83.1 ± 5.3 mL, P = 0.27). Multivariate analysis revealed absence of arterial hypertension, lone AF, ablation success, and initial LA enlargement as independent predictors for significant LAVR following ablation (each P < 0.05). CONCLUSION: Based on the subgroup of patients with lone AF, PVI leads to a significant LAVR 4 months after the procedure, especially in patients with clinical success in terms of AF freedom. Comorbidities such as arterial hypertension may prevent this reverse atrial remodelling, despite AF freedom. Clinical implications need to be further elucidated.

Predicting knee rotation by the projection overlap of the proximal fibula and tibia in long-leg radiographs.

PURPOSE: Rotation of the lower limbs in long-leg radiographs has a significant impact on imaging the mechanical femorotibial angle, the femoral anatomic mechanical angle, the mechanical lateral distal femoral angle (mLDFA) and the mechanical medial proximal tibial angle (mMPTA). In this study, we assessed the rotation of the lower limbs in conventional radiographs and hypothesized that the relative position of the proximal fibula to the proximal tibia on long-leg radiographs is related to the rotation of the knee joint. METHODS: Radiological examinations in different rotational positions of the knee joint (incremental 40° internal to 40° external rotation) were imitated by 50 computed tomography scans (50 patients, 25 men and 25 women). The extent of the projection overlaps of the fibula, the fibular tip and the distance from the fibular tip to the lateral cortex were determined for every rotational position. RESULTS: Multiple regression analysis showed a very strong correlation between the measured fibular parameters and knee rotation between 20° of internal rotation and 40° of external rotation (R (2) ~ 0.94, p < 0.001). By means of these results, we created a formula for predicting knee rotation: [Formula: see text]This strong correlation could not be found between 20° and 40° of internal rotation. DISCUSSION: Because incorrect internal and external rotation negatively influence the correct measurement of angles (mechanical femorotibial angle, femoral anatomic mechanical angle, the mLDFA and the mMPTA), long-leg radiographs should be assessed for proper rotation angles before measurement. Using the provided formula rotation of the lower limb in weight-bearing, long-leg radiographs can be reliably predicted. LEVEL OF EVIDENCE: Diagnostic study, Level II.

Esophageal tissue injury following pulmonary vein isolation using the PVAC: assessment by endoscopy and magnetic resonance imaging.

BACKGROUND: We investigate the frequency of esophageal tissue injury (ETI) following ablation of atrial fibrillation (AF) using the pulmonary vein ablation catheter (PVAC) ascertained by esophageal endoscopy (ESE) and corresponding magnetic resonance imaging (MRI). METHODS: A total of 41 patients with symptomatic AF presenting for pulmonary vein isolation (PVI) were included consecutively in two observational groups. Group A received MRI the day before and ESE plus MRI within 3-4 weeks following the ablation procedure using the PVAC. Group B received MRI the day before and ESE plus MRI within 2 days after PVI. MRI included T2-weighted and T1-weighted postcontrast with fat suppression (fs) and late-enhancement scans to demonstrate postprocedural edema and contrast enhancement of the esophageal wall. RESULTS: A total of 13 (32%) patients were enrolled in Group A (26 ± 11 days post-PVI), and 28 (68%) patients in Group B (2 ± 0.6 days post-PVI). ETI was found by ESE in one (2%) patient (Group B) and resolved under conservative therapy. Corresponding MRI showed a false negative result with no alterations of esophageal structures using T1-weighted, T2-weighted, and late enhancement scans. In addition, false positive results were demonstrated by late-enhancement MRI in five (12%) patients (three patients in Group A and two patients in Group B), which could not be verified by corresponding ESE. CONCLUSIONS: Endoluminal ETI is a rare but possible complication, which should be considered following PVAC procedures. MRI of the esophagus is currently not a reliable screening method due to false positive and negative findings compared to ESE.

Multidetector computed tomography for detection and characterization of pulmonary hypertension in consideration of WHO classification.

OBJECTIVE: We evaluated the reliability of various multidetector computed tomography (MDCT) parameters for diagnosis and severity assessment of pulmonary hypertension (PH) with consideration of World Health Organization (WHO) classification. METHODS: A total of 172 patients were included in this retrospective study. One hundred fourteen patients had a diagnosis of PH (mean pulmonary artery pressure ≥25 mm Hg), and 58 patients without PH (mean pulmonary artery pressure <20 mm Hg) served as control subjects. The patients with PH were grouped according to the WHO classification based on PH etiology. RESULTS: The patients with PH had significantly greater main, left, and right pulmonary artery diameters than the control subjects (P < 0.001). No significant differences within the PH subgroups were found. Receiver operating characteristic analysis showed reasonable sensitivity and specificity for selected MDCT parameters. The severity of PH did not correlate with MDCT parameters. CONCLUSIONS: Easy-to-determine MDCT parameters allow detection of PH independent of the WHO group. In patients with dilated aorta, the vertebra can be an alternative internal standard. Severity of PH cannot be estimated by MDCT parameters.

Influence of percutaneous abscess drainage on severe postoperative septic complications in patients with Crohn's disease.

PURPOSE: Severe postoperative intra-abdominal septic complications (IASC) such as an anastomotic leak, intra-abdominal abscess, and fistula are significantly associated with the presence of spontaneous intra-abdominal abscess at the time of laparotomy in patients with Crohn's disease (CD). The purpose of this study was to compare the incidence of severe postoperative IASC in patients undergoing intestinal resections with and without preoperative percutaneous abscess drainage (PAD) before definitive surgery. METHODS: Using a prospective surgical database, we searched for patients with CD and spontaneous intra-abdominal abscesses who underwent intestinal resection at our hospital from May 2005 to February 2009. Postoperative IASC were defined as anastomotic leaks, abscess, and fistula within 1 month after surgery. We compared the incidence of postoperative IASC in patients with (group I) and without (group II) preoperative PAD (Fisher's exact test). RESULTS: We identified 25 patients (15 men, 10 women; mean age, 31 years) with spontaneous intra-abdominal abscesses. PAD was performed in 12 of 25 patients (48%), with an average of 37 days before surgery (range, 6-83 days). The overall rate of postoperative IASC was 48% (12 of 25 patients). In group I, postoperative IASC occurred in 3 of 12 patients (25%). In group II, postoperative IASC were assessed in 9 of 13 patients (69%). The differences between these two groups were considered to be statistically significant (p = 0.04). CONCLUSION: PAD of intra-abdominal abscesses before surgery could significantly reduce the occurrence of severe postoperative IASC in patients with CD.

Morphometric characteristics of anencephalic skulls - A comparative study.

Anencephaly is the most severe form of a neural tube defect resulting from the incomplete occlusion of the anterior neuropore in the fourth week of development and associated with a severely underdeveloped brain mass. As desmal ossification of the neurocranium is induced by the presence of soft tissues (brain), no bone develops as direct consequence of the missing brain. The cranial base, by contrast, is formed by chondral ossification, which is genetically determined, and thus present also in anencephaly. Morphometric characteristics of anencephalic skulls, however, have not yet been investigated in sufficient detail before. In this study we therefore comparatively assessed macroscopic morphological-anatomical and cephalometric CT data on structures and dimensions of 11 macerated anencephalic and 4 normal neonatal skulls highlighting skeletal morphological differences. The most striking results were the missing skullcap and the greatly changed morphology of the existing skull bones, which were reduced in size. The parameters of the skull base, the transverse orbital diameter and maxillary width were significantly smaller in anencephalic skulls. The morphology of the viscerocranium appeared similar to that of normal neonatal skulls. The results of this study can be used in diagnosis and skeletal classification for anencephaly. This can help identify bones that are incomplete, fragmented and taphonomically altered, which is often the case in historical and forensic studies.

Structured Reporting of Whole-Body Trauma CT Scans Using Checklists: Diagnostic Accuracy of Reporting Radiologists Depending on Their Level of Experience. / Strukturierte Befundung von Polytrauma-CTs mit Checklisten: Diagnostische Genauigkeit in Abhängigkeit von der Erfahrung des Radiologen.

PURPOSE: Evaluation of the diagnostic accuracy of a checklist-style structured reporting template in the setting of whole-body multislice computed tomography in major trauma patients depending on the level of experience of the reporting radiologist. MATERIALS AND METHODS: A total of 140 major trauma scans with the same protocol were included in this retrospective study. In a purely trial-intended reading, the trauma scans were analyzed by three radiologists with different levels of experience (resident, radiologist with 3 years of experience after board certification, and radiologist with 7 years of experience after board certification). The aim was to fill in the checklist 1 template within one minute to immediately diagnose management-altering findings. Checklist 2 was intended for the analysis of important trauma-related findings within 10 minutes. Reading times were documented. The final radiology report and the documented injuries in the patient's medical record were used as gold standard. RESULTS: The evaluation of checklist 1 showed a range of false-negative reports between 5.0 % and 11.4 % with the resident showing the highest accuracy. Checklist 2 showed overall high diagnostic inaccuracy (19.3-35.0 %). The resident's diagnostic accuracy was statistically significantly higher compared to the radiologist with 3 years of experience after board certification (p = 0.0197) and with 7 years of experience after board certification (p = 0.0046). Shorter average reporting time resulted in higher diagnostic inaccuracy. Most of the missed diagnoses were fractures of the spine and ribs. CONCLUSION: By using a structured reporting template in the setting of major trauma computed tomography, less experienced radiologists reach a higher diagnostic accuracy compared to experienced readers. KEY POINTS: · In the setting of a pure trial reading, the diagnostic inaccuracy of template-based reporting of major trauma CT examinations is high.. · Fractures in general and especially of the vertebral bodies and ribs were the most commonly missed diagnoses.. · In a study setting, less experienced radiologists seem to reach a higher diagnostic accuracy when using a structured reporting approach.. CITATION FORMAT: · Dendl LM, Pausch AM, Hoffstetter P et al. Structured Reporting of Whole-Body Trauma CT Scans Using Checklists: Diagnostic Accuracy of Reporting Radiologists Depending on Their Level of Experience. Fortschr Röntgenstr 2021; 193: 1451 - 1460.

Analysis of Thrombotic Deposits in Extracorporeal Membrane Oxygenators by High-resolution Microcomputed Tomography: A Feasibility Study.

Coagulative disorders, especially clotting during extracorporeal membrane oxygenation, are frequent complications. Direct visualization and analysis of deposits in membrane oxygenators using computed tomography (CT) may provide an insight into the underlying mechanisms causing thrombotic events. However, the already established multidetector CT (MDCT) method shows major limitations. Here, we demonstrate the feasibility of applying industrial micro-CT (µCT) to circumvent these restrictions. Three clinically used membrane oxygenators were investigated applying both MDCT and µCT. The scans were analyzed in terms of clot volume and local clot distribution. As validation, the clot volume was also determined from the fluid volume, which could be filled into the respective used oxygenator compared to a new device. In addition, cross-sectional CT images were compared with crosscut oxygenators. Based on the µCT findings, a morphological measure (sphericity) for assessing clot structures in membrane oxygenators is introduced. Furthermore, by comparing MDCT and µCT results, an augmentation of the MDCT method is proposed, which allows for improved clot volume determination in a clinical setting.

Correction of Pelvic Tilt and Pelvic Rotation in Cup Measurement after THA - An Experimental Study.

Purpose Accurate assessment of cup orientation on postoperative pelvic radiographs is essential for evaluating outcome after THA. Here, we present a novel method for correcting measurement inaccuracies due to pelvic tilt and rotation. Method In an experimental setting, a cup was implanted into a dummy pelvis, and its final position was verified via CT. To show the effect of pelvic tilt and rotation on cup position, the dummy was fixed to a rack to achieve a tilt between + 15° anterior and -15° posterior and 0° to 20° rotation to the contralateral side. According to Murray's definitions of anteversion and inclination, we created a novel corrective procedure to measure cup position in the pelvic reference frame (anterior pelvic plane) to compensate measurement errors due to pelvic tilt and rotation. Results The cup anteversion measured on CT was 23.3°; on AP pelvic radiographs, however, variations in pelvic tilt (±â€Š15°) resulted in anteversion angles between 11.0° and 36.2° (mean error 8.3°±â€Š3.9°). The cup inclination was 34.1° on CT and ranged between 31.0° and 38.7° (m. e. 2.3°±â€Š1.5°) on radiographs. Pelvic rotation between 0° and 20° showed high variation in radiographic anteversion (21.2°-31.2°, m. e. 6.0°±â€Š3.1°) and inclination (34.1°-27.2°, m. e. 3.4°±â€Š2.5°). Our novel correction algorithm for pelvic tilt reduced the mean error in anteversion measurements to 0.6°±â€Š0.2° and in inclination measurements to 0.7° (SD±â€Š0.2). Similarly, the mean error due to pelvic rotation was reduced to 0.4°±â€Š0.4° for anteversion and to 1.3°±â€Š0.8 for inclination. Conclusion Pelvic tilt and pelvic rotation may lead to misinterpretation of cup position on anteroposterior pelvic radiographs. Mathematical correction concepts have the potential to significantly reduce these errors, and could be implemented in future radiological software tools. Key Points · Pelvic tilt and rotation influence cup orientation after THA. · Cup anteversion and inclination should be referenced to the pelvis. · Radiological measurement errors of cup position may be reduced by mathematical concepts. Citation Format · Schwarz TJ, Weber M, Dornia C et al. Correction of Pelvic Tilt and Pelvic Rotation in Cup Measurement after THA - An Experimental Study. Fortschr Röntgenstr 2017; 189: 864 - 873.

Magnetic Resonance Imaging of the Axial Skeleton in Patients With Spondyloarthritis: Distribution Pattern of Inflammatory and Structural Lesions.

PURPOSE: Spondyloarthritis is a chronic inflammatory disorder of the musculoskeletal system driven by systemic enthesitis and typically involving the axial skeleton, ie, the spine and the sacroiliac joints. The purpose of this study was to assess the distribution pattern of inflammatory and structural magnetic resonance imaging (MRI) findings in spondyloarthritis. METHODS: Retrospective study of 193 patients with axial spondyloarthritis who received MRI of the spine and the sacroiliac joints. We quantitatively assessed inflammatory and structural lesions using established MRI-based scoring methods. The significance of the differences between gender, HLA-B27 status, and spine and sacroiliac involvement was determined. RESULTS: In total, 174 patients (90.2%) showed a sacroiliac involvement and 120 patients (62.2%) a combined involvement of the sacroiliac joints and the spine. An isolated sacroiliac involvement was found in 54 patients (28.0%) and an isolated spine involvement in 19 patients (9.8%). The sacroiliac joint was significantly more involved in men than in women (P < .01), and men had significantly higher scores for structural lesions (P < .001). The subgroup of HLA-B27-positive patients showed a significantly higher percentage of sacroiliac involvement compared with HLA-B27-negative patients (P < .05). CONCLUSIONS: Spondyloarthritis is a systemic disorder predominantly involving the sacroiliac joints. However, the entire axial skeleton may be affected. In particular, HLA-B27-negative women show atypical manifestations without sacroiliac involvement. Magnetic resonance imaging in spondyloarthritis should cover the entire axial skeleton, ie, sacroiliac joints and the spine to meet the pathophysiology of this disorder and capture the true extent of inflammatory and structural lesions.

Algorithm for efficient PKHD1 mutation screening in autosomal recessive polycystic kidney disease (ARPKD).

Autosomal recessive polycystic kidney disease (ARPKD) is an important cause of childhood renal- and liver-related morbidity and mortality with variable disease expression. While most cases manifest peri-/neonatally with a high mortality rate in the first month of life, others survive to adulthood. ARPKD is caused by mutations in the Polycystic Kidney and Hepatic Disease 1 (PKHD1) gene on chromosome 6p12. PKHD1 is an exceptionally large gene (470 kb) with a longest open reading frame transcript of 67 exons predicted to encode a 4,074-amino acid (aa) (447 kDa) multidomain integral membrane protein (fibrocystin/polyductin) of unknown function. Recent DHPLC-based mutational studies have reported detection rates of about 80% and a minimum of one PKHD1 mutation in more than 95% of families. Thus far, a total of 263 different PKHD1 mutations (639 mutated alleles) are included in the locus-specific database (www.humgen.rwth-aachen.de). Except for a few population-specific founder alleles and the common c.107C>T (p.Thr36Met) missense change, PKHD1 is characterized by significant allelic diversity, making mutation screening time-consuming and labor-intensive. Mutations are distributed throughout the gene's coding sequence; however, they are not equally scattered. Thus, we aimed to set up an algorithm for efficient molecular genetic diagnostics in ARPKD. A total of 80% of known PKHD1 mutations can be identified if a subset of 27 out of 77 DHPLC fragments is screened. The current study provides an essential platform for PKHD1 mutation screening in a routine setting that will largely alleviate molecular genetic diagnostics in patients suspected to have ARPKD.

PKHD1 mutations in families requesting prenatal diagnosis for autosomal recessive polycystic kidney disease (ARPKD).

Autosomal recessive polycystic kidney disease (ARPKD) is one of the most common hereditary renal cystic diseases in children. The clinical spectrum ranges from stillbirth and neonatal demise to survival into adulthood. In a given family, however, patients usually display comparable phenotypes. Many families who lost a child with severe ARPKD desire an early and reliable prenatal diagnosis (PD). Given the limitations of antenatal ultrasound, this is only feasible by molecular genetics that became possible in 1994 when PKHD1, the locus for ARPKD, was mapped to chromosome 6p. However, linkage analysis might prove difficult or even impossible in families with diagnostic doubts or in whom no DNA of an affected child is available. In such cases the recent identification of the PKHD1 gene provides the basis for direct mutation testing. However, due to the large size of the gene, lack of knowledge of the encoded protein's functional properties, and the complicated pattern of splicing, significant challenges are posed by PKHD1 mutation analysis. Thus, it is important to delineate the mutational spectrum and the reachable mutation detection rate among the cohort of severely affected ARPKD patients. In the present study, we performed PKHD1 mutation screening by DHPLC in a series of 40 apparently unrelated families with at least one peri- or neonatally deceased child. We observed 68 out of an expected 80 mutations, corresponding to a detection rate of 85%. Among the mutations identified, 23 were not reported previously. We disclosed two underlying mutations in 29 families and one in 10 cases. Thus, in all but one family (98 percent;), we were able to identify at least one mutation substantiating the diagnosis of ARPKD. Approximately two-thirds of the changes were predicted to truncate the protein. Missense mutations detected were nonconservative, with all but one of the affected amino acid residues found to be conserved in the murine ortholog. PKHD1 mutation analysis has proven to be an efficient and effective means to establish the diagnosis of ARPKD.

PKHD1 mutations in autosomal recessive polycystic kidney disease (ARPKD).

Autosomal recessive polycystic kidney disease (ARPKD) is an important cause of childhood renal- and liver-related morbidity and mortality. The clinical spectrum is widely variable. About 30 to 50% of affected individuals die in the neonatal period, while others survive into adulthood. ARPKD is caused by mutations in the PKHD1 (polycystic kidney and hepatic disease 1) gene on chromosome 6p12, which is among the largest human genes, with a minimum of 86 exons assembled into a variety of alternatively spliced transcripts. The longest continuous open reading frame is predicted to yield a 4,074-aa (447-kDa) multidomain integral membrane protein (fibrocystin/polyductin) of unknown function. This update compiles all known PKHD1 mutations and polymorphisms/sequence variants. Mutations were found to be scattered throughout the gene without evidence of clustering at specific sites. Most PKHD1 mutations are unique to single families ("private mutations") hampering genotype-phenotype correlations. Correlations have been drawn for the type of mutation rather than for the site of individual mutations. All patients carrying two truncating mutations displayed a severe phenotype with perinatal or neonatal demise, while patients surviving the neonatal period bear at least one missense mutation. However, some missense changes are obviously as devastating as truncating mutations. The present article intends 1) to provide an overview of PKHD1 mutations and polymorphisms/sequence variants identified so far, 2) to discuss potential genotype-phenotype correlations, and 3) to review them in the context of their clinical implications. A constantly updated list of mutations is available online (www.humgen.rwth-aachen.de) and investigators are invited to submit their novel data to this PKHD1 mutation database.

Diagnostic significance of rib series in minor thorax trauma compared to plain chest film and computed tomography.

BACKGROUND: Rib series (RS) are a special radiological technique to improve the visualization of the bony parts of the chest. OBJECTIVES: The aim of this study was to evaluate the diagnostic accuracy of rib series in minor thorax trauma. METHODS: Retrospective study of 56 patients who received RS, 39 patients where additionally evaluated by plain chest film (PCF). All patients underwent a computed tomography (CT) of the chest. RS and PCF were re-read independently by three radiologists, the results were compared with the CT as goldstandard. Sensitivity, specificity, negative and positive predictive value were calculated. Significance in the differences of findings was determined by McNemar test, interobserver variability by Cohens kappa test. RESULTS: 56 patients were evaluated (34 men, 22 women, mean age =61 y.). In 22 patients one or more rib fracture could be identified by CT. In 18 of these cases (82%) the correct diagnosis was made by RS, in 16 cases (73%) the correct number of involved ribs was detected. These differences were significant (p = 0.03). Specificity was 100%, negative and positive predictive value were 85% and 100%. Kappa values for the interobserver agreement was 0.92-0.96. Sensitivity of PCF was 46% and was significantly lower (p = 0.008) compared to CT. CONCLUSIONS: Rib series does not seem to be an useful examination in evaluating minor thorax trauma. CT seems to be the method of choice to detect rib fractures, but the clinical value of the radiological proof has to be discussed and investigated in larger follow up studies.

D-dimers as an early marker for oxygenator exchange in extracorporeal membrane oxygenation.

PURPOSE: Early markers of oxygenator dysfunction during prolonged use of extracorporeal membrane oxygenation (ECMO) are important for timely exchange to avoid sudden loss of function due to clot formation within the system. The measurement of D-dimers (DDs) in plasma might be a marker for early diagnosis of thrombus formation and dysfunction of heparin-coated membrane oxygenators (MOs). METHODS: This is a retrospective study on prospectively collected data of 24 adult acute respiratory distress syndrome patients requiring long-term veno-venous ECMO with at least 1 MO exchange. Kinetics of coagulation, inflammation, and oxygenator function were analyzed before and after MO exchange. RESULTS: Median (interquartile range) support duration is 20 (15-29) days. Thirty-four MOs had to be replaced. Exchange occurred due to visible thrombus formation in the MO (n=16), worsening gas exchange (n=11), increased blood flow resistance (n=1), and activation of coagulation with diffuse bleeding (n=6). In 15 cases, DDs were continuously elevated and, therefore, not suitable as marker for MO exchange. In the remaining 19 cases, DDs increased significantly within 3 days before exchange from 15 (9-20) to 30 (21-35) mg/dL (P=.002) and declined significantly within 1 day thereafter to 13 (7-17) mg/dL (P=.003). CONCLUSIONS: An increase in plasma DD concentration in absence of other explaining pathology can be helpful in predicting an MO exchange in miniaturized heparin-coated ECMO systems.

Identification of early complications following pancreas and renal transplantation using contrast enhanced ultrasound (CEUS)--first results.

AIM: Identification of acute and subacute complications following pancreas and renal transplantation using contrast enhanced ultrasound (CEUS) in comparison with Magnetic Resonance Tomography (MRI), Computed Tomography (CT), Digital Subtraction Angiography (DSA) or Ultrasound (US). The study evaluated whether CEUS could confirm the preliminary diagnosis or even provide additional information, relevant for the therapeutic strategy. MATERIAL AND METHODS: Retrospective evaluation of 19 patients (13 male, 6 female, age 26-77 years, mean 53.2 years) following renal transplantation and 10 patients (4 male, 6 female, age 35-56 years, mean 45.7 years) following combined pancreas and renal transplantation. CEUS was used as an additional diagnostic method when obscure diagnostic findings occurred in US, CT, MRI or DSA. Fundamental B-scan, Color Coded Doppler Sonography (CCDS) and CEUS were performed in all patients by an experienced examiner using a multifrequency convex transducer (1-5 MHz). After a bolus injection of up to 2.4 ml SonoVue® [BRACCO, Italy] digital raw data was stored as cine-loops up to 5 minutes in length. RESULTS: In all patients, the pathological features and suspected diagnostic findings identified in the other imaging modalities could be confirmed using CEUS (100%). In 25 out of 29 patients (86.2%), new clinically relevant findings were detected. In 27 patients, the diagnosis of CEUS was confirmed during surgery (7), DSA (5), follow-up CEUS (13), CT (1) and MRI (1). In 4 patients renal AV-fistulas were found following biopsy, 3 patients showed post-operative allograft arterial stenosis or dissection, 1 patient demonstrated a stenosis of the common iliac artery and 2 patients were diagnosed with post-operative allograft venous thrombosis or stenosis. In 2 patients, a definite diagnosis of a benign lesion following renal transplantation was possible. In 1 patient a malignant lesion was suspected and confirmed following surgery. In 6 patients, normal perfusion of the pancreas and renal parenchyma and the corresponding vessels was diagnosed, in 5 patients the parenchymal perfusion was diminished and 1 patient suffered from pancreatitis. CONCLUSION: These first results show that CEUS can provide additional, clinically relevant informations in patients with acute and subacute complications following pancreas and renal transplantation. Thus, an early application within the diagnostic course seems favorable.

Efficiency of gas transfer in venovenous extracorporeal membrane oxygenation: analysis of 317 cases with four different ECMO systems.

PURPOSE: Polymethylpentene membrane oxygenators used in venovenous extracorporeal membrane oxygenation (vvECMO) differ in their physical characteristics. The aim of the study was to analyze the gas transfer capability of different ECMO systems in clinical practice, as the choice of the appropriate system may be influenced by the needs of the patient. METHODS: Retrospective study on prospectively collected data of adults with severe respiratory failure requiring vvECMO support (Regensburg ECMO Registry, 2009-2013). Oxygen (O2) transfer and carbon dioxide (CO2) elimination of four different ECMO systems (PLS system, n = 163; Cardiohelp system (CH), n = 59, Maquet Cardiopulmonary, Rastatt, Germany; Hilite 7000 LT system, n = 56, Medos Medizintechnik, Stolberg, Germany; ECC.05 system, n = 39, Sorin Group, Mirandola (MO), Italy) were analyzed. RESULTS: Gas transfer depended on type of ECMO system, blood flow, and gas flow (p ≤ 0.05, each). CO2 removal is dependent on sweep gas flow and blood flow, with higher blood flow and/or gas flow eliminating more CO2 (p ≤ 0.001). CO2 elimination capacity was highest with the PLS system (p ≤ 0.001). O2 transfer at blood flow rates below 3 l/min depended on blood flow, at higher blood flow rates on blood flow and gas flow. The system with the smallest gas exchange surface (ECC.05 system) was least effective in O2 transfer, but in terms of the gas exchange surface was the most effective. CONCLUSION: Our analysis suggests that patients with severe hypoxemia and need for high flow ECMO benefit more from the PLS/CH or Hilite 7000 LT system. The ECC.05 system is advisable for patients with moderate hypoxemia and/or hypercapnia.

Analysis of thrombotic deposits in extracorporeal membrane oxygenators by multidetector computed tomography.

Oxygenator thrombosis is a serious complication in extracorporeal membrane oxygenation (ECMO) and may necessitate a system exchange. Coagulation and fibrinolysis parameters, flow dynamics, and gas transfer performance are currently used to evaluate the degree of oxygenator thrombosis, but there is no technical approach for direct visualization and quantification of thrombotic deposits within the membrane oxygenator (MO). We used multidetector computed tomography (MDCT) with three-dimensional postprocessing to assess the incidence of oxygenator thrombosis, to quantify thrombus extent, and to localize clot distribution. Twenty heparin-coated MOs after successful weaning were analyzed. Mean ECMO support time was 7 ± 4 days, mean activated partial thromboplastin time (aPTT) during ECMO was 59 ± 20 seconds. Thrombotic deposits were detected in all MOs. The mean clot volume was 51.7 ± 22.3 cm. All thrombotic deposits were located in the venous, i.e., inlet part of the device, without apparent evidence of embolization in patients. There was no correlation between clot volume and ECMO support time or aPTT. Clot formation within the MO is a common finding in ECMO despite adequate systemic anticoagulation. The clinical significance of thrombus formation and its influence on gas exchange capacity and hemostatic complications have to be addressed in further studies.

Increased pulmonary artery diameter on chest computed tomography can predict borderline pulmonary hypertension.

Pulmonary hypertension (PH) often leads to dilatation of the pulmonary artery (PA), which can be measured on chest computed tomography (CT). While the predictive capability of PA dilatation is useful to distinguish PH (mean PA pressure ≥25 mmHg) from normal (mean PA pressure ≤ 20 mmHg), CT characteristics of borderline PH (mean PA pressure 21-24 mmHg) have not been described. We aimed to investigate whether patients with borderline PH already show PA dilatation and to assess the diagnostic accuracy of PA dilatation for borderline PH diagnosis. Between April 2003 and September 2008, consecutive symptomatic patients with a mean PA pressure below 25 mmHg on right heart catheterization who had a chest CT available were retrospectively included. PA diameters from chest CT were correlated with hemodynamic measurements and analyzed with respect to their accuracy of predicting borderline PH. Main PA diameters were significantly larger in 26 patients with borderline PH compared with 52 patients without PH (3.16 ± 0.53 vs. 2.78 ± 0.43 cm, P = 0.001). The main PA diameter on CT correlated with mean PA pressure (r = 0.496, P < 0.001) and pulmonary vascular resistance (r = 0.445, P < 0.001), and predicted borderline PH with sensitivity, specificity, negative and positive predictive values of 77%, 62%, 84%, and 50%, respectively, using a cutoff ≥2.9 cm. This first systematic investigation of CT parameters in symptomatic patients with mean PA pressures less than 25 mmHg could show that, even in patients with borderline PH, significant PA dilatation can be present, which was related to PA pressure and pulmonary vascular resistance. This can be useful for identification of patients with borderline PH for further study and to prompt further diagnostic work-up of possible underlying diseases.