Antithrombotic Strategy in the Three First Months following Bioprosthetic Heart Valve Implantation

Heart valve prosthesis unquestionably improve quality of life and survival of patients with severe valvular heart disease, but the need for antithrombotic therapy to prevent thromboembolic complications is a major challenge to clinicians and their patients. Of the articles analyzed, most were retrospective series of cases or historical cohorts obtained from the database. The few published randomized trials showed no statistical power to assess the primary outcome of death or thromboembolic event. In this article, we decided to perform a systematic literature review, in an attempt to answer the following question: what is the best antithrombotic strategy in the first three months after bioprosthetic heart valve implantation (mitral and aortic)?After two reviewers applying the extraction criteria, we found 1968 references, selecting 31 references (excluding papers truncated, which combined bioprosthesis with mechanical prosthesis, or without follow-up).Based on this literature review, there was a low level of evidence for any antithrombotic therapeutic strategy evaluated. It´s therefore interesting to use aspirin 75 to 100 mg / day as antithrombotic strategy after bioprosthesis replacement in the aortic position, regardless of etiology, for patients without other risk factors such as atrial fibrillation or previous thromboembolic event. In the mitral position, the risk of embolism, although low, is more relevant than in the aortic position, according to published series and retrospective cohorts comprised mostly of elderly non-rheumatic patients.The current evidence is limited to have a consistent and safe level of evidence regarding the best therapeutic strategy. Based on these studies, 75 to 100 mg/day of aspirin is interesting as antithrombotic strategy after implantation of aortic bioprosthesis, regardless of etiology, for patients with no other risk factors such as atrial fibrillation or previous thromboembolic event. As for mitral bioprosthesis, the risk of embolism, although low, is more relevant than in the aortic position, according to published series and retrospective cohorts - usually elderly non rheumatic patients.     

Left Ventricular Torsion Parameters are Affected by Acute Changes in Load

Background: Quantification of left ventricular torsion may provide new indices of systolic and diastolic function. We sought to characterize the effect of acute manipulation of load on cardiac torsion, plecotropy in human subjects. Methods: Simultaneous Millar LV pressure, micromanometry, and echocardiograms were performed on 18 patients (10 male, mean age 66 years) with normal systolic function. Loading was altered sequentially by the administration of glyceryl trinitrate (GTN) and saline fluid loading. Echocardiographic speckle tracking imaging was used to quantify LV torsion and event timing was recorded relative to mitral valve opening (MVO). Results: GTN administration decreased preload (LV end diastolic pressure: 15.7 vs 8.4 mmHg, P < 0.001), and afterload (wall stress: 140 vs 84 ×10³dyn/cm², P < 0.02). Administration of fluid increased preload (LVEDP 11.3 vs 18.1 mmHg, P < 0.001) and increased wall stress, but to a lesser extent (102 vs 117 ×10³dyn/cm², P < 0.003). GTN administration augmented peak torsion (8.4 vs 11.0 deg, P < 0.05), increased systolic torsion velocity (46.6 vs 65.3deg/sec, P < 0.01) and resulted in earlier onset of untwisting (–105 vs –127ms, P < 0.05). Fluid loading decreased the proportion of untwisting prior to MVO (39.0 vs 31.0%, P < 0.05), untwisting acceleration (–750 vs –592deg/sec/sec, P < 0.05) and delayed the timing of peak untwisting (–37.0 vs 9.1ms, P < 0.01), but did not affect systolic torsion parameters. Conclusions: Left ventricular torsion parameters are sensitive to acute changes in load and therefore need to be interpreted in the context of current loading conditions. (ECHOCARDIOGRAPHY 2010;27:407‐414)     

Investigating the predictive value of whole-brain structural MR scans in autism: A pattern classification approach

Autistic spectrum disorder (ASD) is accompanied by subtle and spatially distributed differences in brain anatomy that are difficult to detect using conventional mass-univariate methods (e.g., VBM). These require correction for multiple comparisons and hence need relatively large samples to attain sufficient statistical power. Reports of neuroanatomical differences from relatively small studies are thus highly variable. Also, VBM does not provide predictive value, limiting its diagnostic value.Here, we examined neuroanatomical networks implicated in ASD using a whole-brain classification approach employing a support vector machine (SVM) and investigated the predictive value of structural MRI scans in adults with ASD. Subsequently, results were compared between SVM and VBM. We included 44 male adults; 22 diagnosed with ASD using “gold-standard” research interviews and 22 healthy matched controls.SVM identified spatially distributed networks discriminating between ASD and controls. These included the limbic, frontal-striatal, fronto-temporal, fronto-parietal and cerebellar systems. SVM applied to gray matter scans correctly classified ASD individuals at a specificity of 86.0% and a sensitivity of 88.0%. Cases (68.0%) were correctly classified using white matter anatomy. The distance from the separating hyperplane (i.e., the test margin) was significantly related to current symptom severity. In contrast, VBM revealed few significant between-group differences at conventional levels of statistical stringency.We therefore suggest that SVM can detect subtle and spatially distributed differences in brain networks between adults with ASD and controls. Also, these differences provide significant predictive power for group membership, which is related to symptom severity.     

Urinary disease in 2 Dogon populations with different exposure to Schistosoma haematobium infection: progression of bladder and kidney diseases in children and adults

BACKGROUND: Schistosoma haematobium infection causes severe urinary disease and considerable mortality. The factors that determine disease progression from mild to severe stages are not fully understood. METHODS: Here we describe a cross-sectional epidemiological study of kidney and bladder diseases in 2 Dogon populations with different exposure to S. haematobium infection. RESULTS: Early and high exposure resulted in more-severe disease, especially among young subjects, without clear evidence of a more-rapid development of immunity. Nevertheless, 50%-60% of subjects of all age classes in both villages showed no evidence of disease. Kidney and bladder disease peaked biphasically among young subjects and adults >25 years old. The first peak corresponded with infections of maximum intensity, whereas the second peak occurred among adults with infections of very low intensity. Kidney disease was correlated with circulating anodic antigen concentration in serum, whereas bladder disease was correlated with egg count and eosinophil cationic protein concentration in urine. Kidney and bladder disease did not correlate. Severe kidney disease was more frequent in certain families. CONCLUSIONS: The frequency of urinary disease is increased by infections acquired early during life, is regulated by strong clinical immunity in certain subjects, and may be dependent on hereditary factors. Kidney and bladder disease may involve different mechanisms of pathogenesis, which may differ between children and adults.     

Elevated serum parathyroid hormone concentration in eucalcemic patients after parathyroidectomy for primary hyperparathyroidism and its relationship to vitamin D profile

Elevation of serum parathyroid hormone (PTH) level in eucalcemic patients after parathyroidectomy for primary hyperparathyroidism has been described in up to 40% of patients, but little is known about its etiology or clinical significance. To better understand the cause of this phenomenon, we studied 49 patients without renal dysfunction or osteomalacia who underwent parathyroidectomy for primary hyperparathyroidism. Patients were categorized into 2 groups based on their serum PTH and calcium levels after parathyroidectomy: (1) elevated PTH with eucalcemia (n = 21), (2) normal PTH with eucalcemia (n = 28). Elevation of serum PTH with eucalcemia after parathyroidectomy occurred in 43% of patients. Patients in group 1 had significantly higher preoperative and postoperative mean serum PTH levels and significantly lower postoperative serum levels of 1,25(OH)(2)D(3), 1,25(OH)(2)D(3)/25(OH)D(3) ratio, and 1,25(OH)(2)D(3)/PTH ratio compared with patients in group 2. Serum PTH in group 1 patients normalized as early as 3 months, but remained elevated in some patients for more than 4 years, and was not associated with development of recurrent hypercalcemia. Normalization of serum PTH in group 1 patients was associated with significant increase in 1,25(OH)(2)D(3) and 1,25(OH)(2)D(3)/PTH ratio. Our data suggest that elevation of serum PTH in eucalcemic patients after parathyroidectomy is a frequently reversible state of resistance of the kidneys to PTH-mediated 1-alpha hydroxylation of 25(OH)D(3) and does not signify subsequent recurrence of hyperparathyroidism.     

Increased incidence of subacute lead perforation noted with one implantable cardioverter-defibrillator.

BACKGROUND: The rapid evolution of implantable cardioverter-defibrillator (ICD) leads has resulted in thinner active fixation leads. While these advances have made the leads more versatile, new configurations may be associated with unforeseen complications. OBJECTIVE: The purpose of this study was to determine the incidence of perforation and dislodgement of defibrillator leads in a single center in the year 2005. METHODS: All patients who underwent percutaneous ICD implantation at the Massachusetts General Hospital using an endocardial right ventricular lead were included in this study. The specific leads analyzed were the Riata (1580/1581 and 1590/1591, St. Jude Medical, St Paul, Minnesota, USA;) and Sprint Fidelis (6949-65, Medtronic, Minneapolis, Minnesota, USA.). Information was collected retrospectively. RESULTS: A total of 130 Riata leads and 111 Sprint Fidelis leads were implanted at the Massachusetts General Hospital during this time period. A total of five lead perforations occurred in patients implanted with the Riata lead as compared with none with the Sprint Fidelis lead (3.8% vs. 0%, respectively; P <.05). Two of the five patients with perforation required pericardiocentesis for tamponade. Clinical symptoms of perforation developed 1-10 days after implant. Moreover, there were five additional lead revisions in the Riata group, which were likely due to dislodgement and/or microperforation, as compared with none in the Sprint Fidelis group (7.7% vs. 0%, respectively; P <.005). CONCLUSIONS: In 2005, at one institution, there were significantly more cardiac perforations and lead revisions with the Riata lead as compared with the Sprint Fidelis right ventricular defibrillator lead. Further data are required to determine whether certain lead characteristics are responsible for this observation.     

Factors affecting error in integration of electroanatomic mapping with CT and MR imaging during catheter ablation of atrial fibrillation

Objective Integration of 3-D electroanatomic mapping with Computed Tomographic (CT) and Magnetic Resonance (MR) imaging is gaining acceptance to facilitate catheter ablation of atrial fibrillation. This is critically dependent on accurate integration of electroanatomic maps with CT or MR images. We sought to examine the effect of patient- and technique-related factors on integration accuracy of electroanatomic mapping with CT and MR imaging of the left atrium. Materials and methods Sixty-one patients undergoing catheter-based atrial fibrillation (AF) ablation procedures were included. All patients underwent cardiac CT (n = 11) or MR (n = 50) imaging, and image integration with real-time electroanatomic mapping of the aorta and left atrium (LA). CARTO-Merge software (Biosense-Webster) was used to calculate the overall average accuracy of integration of electroanatomic points with the CT and MR-derived reconstructions of the LA and aorta. Results There was a significant correlation between LA size assessed by electroanatomic mapping (112 ± 31 ml) and average integration error (1.9 ± 0.6 mm) (r = 0.46, p = 0.0003). There was also greater integration error for patients with LA volume ≥ 110 ml (n = 31) versus < 110 ml (n = 30) (p = 0.004). In contrast, there was no significant association between average integration error and paroxysmal versus persistent AF, left ventricular ejection fraction, days from imaging to electroanatomic mapping, or images derived from CT versus MR. Conclusions Patients with larger LA volume may be prone to greater error during integration of electroanatomic mapping with CT and MR imaging. Strategies to reduce integration error may therefore be especially useful in patients with large LA volume.