Global longitudinal strain (GLS) and basal longitudinal strain (BLS) assessed using two-dimensional speckle-tracking imaging have been proposed as subtle markers of left ventricular (LV) systolic ...dysfunction with potential prognostic value in patients with aortic stenosis (AS). The aim of this study was to evaluate the relationship between longitudinal strain and symptomatic status in patients with AS.
GLS and BLS were measured in 171 patients with pure, isolated, at least mild AS prospectively enrolled at two institutions. The population was divided into four groups: asymptomatic nonsevere AS (n = 55), asymptomatic severe AS with preserved LV ejection fraction (LVEF; ≥50%) (n = 37), symptomatic severe AS with preserved LVEF (n = 60), and severe AS with reduced LVEF (<50%) (n = 19).
GLS was significantly different among the four groups (P < .0001), but the difference was due mainly to patients with reduced LVEFs. In addition, there was an important overlap among the groups, and in multivariate analysis, after adjustment for age, gender, AS severity, and LVEF, GLS was not an independent predictor of symptomatic status (P = .07). BLS was also significantly different among the four groups (P < .0001) but in contrast was independently associated with symptomatic status (P < .0001). However, as for GLS, there was an important overlap between groups and differences were close to intraobserver or interobserver variability (1.3 ± 1.1% and 2.0 ± 1.6%, respectively).
In this prospective multicenter cohort of patients with wide ranges of AS severity, symptoms, and LVEFs, BLS but not GLS was independently associated with symptomatic status. However, there was an important overlap among groups, and differences were close to measurements' reproducibility, raising caution regarding the use of longitudinal strain, at least as a single criterion, in the decision-making process for patients with severe asymptomatic AS.
In sub-Saharan Africa (SSA), precipitation is an important driver of agricultural production. In Uganda, maize production is essentially rain-fed. However, due to changes in climate, projected maize ...yield targets have not often been met as actual observed maize yields are often below simulated/projected yields. This outcome has often been attributed to parallel gaps in precipitation. This study aims at identifying maize yield and precipitation gaps in Uganda for the period 1998–2017. Time series historical actual observed maize yield data (hg/ha/year) for the period 1998–2017 were collected from FAOSTAT. Actual observed maize growing season precipitation data were also collected from the climate portal of World Bank Group for the period 1998–2017. The simulated or projected maize yield data and the simulated or projected growing season precipitation data were simulated using a simple linear regression approach. The actual maize yield and actual growing season precipitation data were now compared with the simulated maize yield data and simulated growing season precipitation to establish the yield gaps. The results show that three key periods of maize yield gaps were observed (period one: 1998, period two: 2004–2007 and period three: 2015–2017) with parallel precipitation gaps. However, in the entire series (1998–2017), the years 2008–2009 had no yield gaps yet, precipitation gaps were observed. This implies that precipitation is not the only driver of maize yields in Uganda. In fact, this is supported by a low correlation between precipitation gaps and maize yield gaps of about 6.3%. For a better understanding of cropping systems in SSA, other potential drivers of maize yield gaps in Uganda such as soils, farm inputs, crop pests and diseases, high yielding varieties, literacy, and poverty levels should be considered.
Article Highlights
When actual maize yields are less than simulated maize yields, maize yield gaps are said to exist
Precipitation gaps occur when actual precipitation is below simulated precipitation
Maize yields are driven by precipitation and other variables like soils and socio-economic circumstances
Background
Bleeding originating in the gastrointestinal (GI) tract is one of the most common adverse events after left ventricular assist device (LVAD) implantation. In these patients, GI bleeding ...appears to be the consequence of altered hemostasis on the one hand and alterations of the GI microvasculature on the other.
Case Report
We report the case of a patient who suffered repeated, severe GI bleeding early after implantation of a HeartMate II continuous‐flow LVAD.
Results
After failure of conventional treatment strategies, GI bleeding was controlled using repeated transfusions of a purified von Willebrand factor (VWF) concentrate, almost devoid of Factor VIII (Wilfactin, LFB). No episodes of pump thrombosis were noted. Subsequent to VWF transfusions, we observed a progressive normalization of circulating vascular endothelial growth factor levels.
Conclusions
Our data raise the possibility that, in addition to its hemostatic properties, transfusions of VWF might have acted as an antiangiogenic factor.
Climate projections in Sub-Saharan Africa (SSA) forecast an increase in the intensity and frequency of droughts with implications for maize production. While studies have examined how maize might be ...affected at the continental level, there have been few national or sub-national studies of vulnerability. We develop a vulnerability index that combines sensitivity, exposure and adaptive capacity and that integrates agroecological, climatic and socio-economic variables to evaluate the national and spatial pattern of maize yield vulnerability to droughts in Uganda. The results show that maize yields in the north of Uganda are more vulnerable to droughts than in the south and nationally. Adaptive capacity is higher in the south of the country than in the north. Maize yields also record higher levels of sensitivity and exposure in the north of Uganda than in the south. Latitudinally, it is observed that maize yields in Uganda tend to record higher levels of vulnerability, exposure and sensitivity towards higher latitudes, while in contrast, the adaptive capacity of maize yields is higher towards the lower latitudes. In addition to lower precipitation levels in the north of the country, these observations can also be explained by poor soil quality in most of the north and socio-economic proxies, such as, higher poverty and lower literacy rates in the north of Uganda.
We sought to evaluate the relationship among left ventricular outflow tract diameter (LVOTd), gender, and body surface area (BSA) and to evaluate the usefulness of size-adjusted LVOTd reference ...values in patients with aortic stenosis (AS). AS grading is based on the echocardiographic calculation of the aortic valve area (AVA) and requires LVOTd measurements, one main potential source of error. Transesophageal echocardiography (TEE) is reputed to be more accurate than transthoracic echocardiography (TTE), but validation studies are rare. A safeguard for LVOTd measurements is thus desirable.
Since January 2006, 3 subsets of patients have been prospectively and concurrently enrolled: 1) TEE group: In 120 patients with and without AS, we prospectively measured LVOTd during both TTE and TEE. 2) Validation set: In 382 patients without aortic valve or ascending aorta diseases, we evaluated the relationship among LVOTd, gender, and BSA. 3) Testing set: In 173 patients with AS, we compared the AVA obtained using measured LVOTd (AVA(MEAS)) and calculated LVOTd derived from a regression determined in the validation set (AVA(CALC)).
TTE did not differ from and correlated well with TEE measurements overall (23 +/- 2 mm vs 23 +/- 2 mm, P = .26; r = 0.95, P < .0001) and in patients with AS (N = 43) (24 +/- 2 mm vs 24 +/- 3 mm, P = .15; r = 0.92, P < .0001). LVOTd was linearly correlated to BSA independently of gender (LVOTd = 5.7 * BSA+12.1; r = 0.55, P < .0001). In the testing set, AVA(CALC) did not differ from and correlated well with AVA(MEAS) (1.20 +/- 0.42 cm2 vs 1.23 +/- 0.40 cm2; P = .08; r = 0.89; P < .0001).
TTE and TEE measurements of the LVOTd provided similar results. LVOTd was significantly associated to BSA and LVOTd, derived from a linear regression linked to BSA independently of gender, provided an acceptable approximation of the AVA. Thus, although accurate measurement of LVOTd is a crucial part of the echocardiographic evaluation of AS severity, the present equation may be used as a safeguard when this measurement is difficult or not possible with TTE.
Whether transesophageal echocardiography (TEE) should be routinely performed before hospital discharge after Bentall surgery remains unclear. The investigators took advantage of this practice at ...their institution to evaluate its benefit.
All patients who had undergone the Bentall procedure at Bichat Hospital from January 2010 to March 2014 were included. For each patient, transthoracic echocardiographic and transesophageal echocardiographic data and clinical events were retrospectively collected from the various reports.
One hundred ninety-eight patients underwent the Bentall procedure during the study period. Postoperative TEE was performed in 117 patients (59.1%), including nine with abnormalities observed on transthoracic echocardiography (a vibrating element on the new prosthetic valve, suspicion of peritubular complications in two patients, and aortic regurgitation in six patients). In 108 patients, routine TEE was performed (i.e., without clinical indication beyond baseline postoperative imaging). Patients with and those without routine TEE were identical, except for more frequent endocarditis as an indication for surgery in patients with routine TEE. Routine TEE did not reveal any new findings that prior transthoracic echocardiography had not shown. The most frequent finding on transthoracic echocardiography or TEE was periaortic hematoma, which sometimes led to the performance of computed tomography. This imaging did not change the care of the patients in this population.
This study does not support the performance of TEE after Bentall surgery during the in-hospital course in the absence of a specific indication. Baseline postoperative imaging using TEE or computed tomography should preferably be recommended beyond the early postoperative period after periaortic hematoma has resolved.
Echocardiography plays a key role in the diagnosis of infective endocarditis (IE) but can be inconclusive in patients in whom prosthetic valve endocarditis (PVE) is suspected. The incremental ...diagnostic value of (18)F-FDG PET and radiolabeled leukocyte scintigraphy in IE patients has already been reported. The aim of this study was to compare the respective performance of (18)F-FDG PET and leukocyte scintigraphy for the diagnosis of PVE in 39 patients.
(18)F-FDG PET and leukocyte scintigraphy were performed on 39 consecutive patients admitted because of clinically suspected PVE and inconclusive echocardiography results. The results of (18)F-FDG PET and leukocyte scintigraphy were analyzed separately and retrospectively by experienced physicians masked to the results of the other imaging technique and to patient outcome. The final Duke-Li IE classification was made after a 3-mo follow-up.
Of the 39 patients, 14 were classified as having definite IE, 4 as having possible IE, and 21 as not having IE. The average interval between (18)F-FDG PET and leukocyte scintigraphy was 7 ± 7 d. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 93%, 71%, 68%, 94%, and 80%, respectively, for (18)F-FDG PET and 64%, 100%, 100%, 81%, and 86%, respectively, for leukocyte scintigraphy. Discrepancies between the results of (18)F-FDG PET and leukocyte scintigraphy occurred in 12 patients (31%). In patients with definite IE, 5 had true-positive (18)F-FDG PET results but false-negative leukocyte scintigraphy results. Of these 5 patients, 3 had nonpyogenic microorganism IE (Coxiella or Candida). Of patients for whom endocarditis had been excluded, 6 had true-negative leukocyte scintigraphy results but false-positive (18)F-FDG PET results. These 6 patients had been imaged in the first 2 mo after the last cardiac surgery. The last patient with a discrepancy between (18)F-FDG PET and leukocyte scintigraphy was classified as having possible endocarditis and had positive (18)F-FDG PET results and negative leukocyte scintigraphy results.
(18)F-FDG PET offers high sensitivity for the detection of active infection in patients with suspected PVE and inconclusive echocardiography results. Leukocyte scintigraphy offers a higher specificity, however, than (18)F-FDG PET for diagnosis of IE and should be considered in cases of inconclusive (18)F-FDG PET findings or in the first 2 mo after cardiac surgery.
OBJECTIVES—The purpose of this study was to investigate whether thoracic ascending aortic aneurysm (TAAA) induces platelet activation as mural thrombus participates in aortic dilatation in abdominal ...aortic aneurysm and TAAA are associated with rheological factors favoring coagulation activation.
METHODS AND RESULTS—We studied the relation between coagulation activation and aortic diameter in Marfan patients (MFS) with various aortic diameters (n=52). We then studied patients presenting large aneurysms associated with bicuspid aortic valve (BAV) and degenerative form. Lastly, we used immunochemistry and biochemistry to investigate prothrombin/thrombin retention within the aortic wall. Microparticles, sGPV, tissue factor, and TAT complexes were increased in plasma from MFS with large aneurysms (≥45 mm) compared to MFS with limited aortic dilatation (<45 mm). Similar elevations were observed in all patients with large aortic aneurysms, regardless of the etiology, the site of maximal aortic dilation, associated valvulopathy, risk factors, or treatments. P-selectin and platelet-bound fibrinogen were also increased, demonstrating platelet activation in large aneurysms. Significant increase in sCD146 plasma concentration suggested alteration of endothelium.
CONCLUSIONS—Platelet activation occurs in patients with large aneurysms of the ascending aorta, is dependent on aortic dilation, and is associated with thrombin generation, part of which appears to be retained in mucoid degeneration areas.
In patients with mitral stenosis (MS) in sinus rhythm (SR), guidelines recommend anticoagulation if the left atrium is enlarged based on diameter measurements. We sought to compare the association of ...left atrial (LA) diameter and LA volume with markers of thromboembolic risk (peak LA appendage emptying velocity LAAv and LA spontaneous contrast density) measured during transesophageal echocardiography in 152 patients with moderate to severe MS. High thromboembolic risk was defined by a peak LAAv <25 cm/s and/or dense spontaneous contrast. Mean LA diameter (50 ± 7 mm, 32 to 77) and LA volume (152 ± 70 ml, 67 to 720) were significantly correlated (r = 0.71, p <0.0001), but the relation was curvilinear and the 95% confidence interval increased with LA diameter. In the subset of 80 patients in SR who underwent clinically indicated transesophageal echocardiography, body surface area (BSA)-indexed LA volume but not LA diameter differentiated patients with normal from those with low LAAv (86 ± 17 vs 71 ± 17 ml/m2 , p <0.01, and 50 ± 6 vs 48 ± 6 mm, p = 0.13, respectively) and patients with dense spontaneous contrast from those with no or mild spontaneous contrast (81 ± 16 vs 63 ± 15 ml/m2 , p <0.01, and 49 ± 6 vs 46 ± 5 mm, p = 0.11, respectively). BSA-indexed LA volume provided the highest area under the curve (0.85) for high thromboembolic risk and LA diameter the lowest (0.65). A BSA-indexed LA volume >60 ml/m2 provided an excellent 90% sensitivity despite 44% specificity, 76% positive predictive value, and 70% negative predictive value. Use of this threshold instead of 50 or 55 mm would have changed the indication for anticoagulation in 51% to 77% of patients. In conclusion, LA volume was more strongly associated with markers of thromboembolic risk than LA diameter, which poorly reflected LA size. Our results support the use of BSA-indexed LA volume to guide the decision for anticoagulation in patients with MS in SR, which may lead to significant change in the management of those patients. We suggest a threshold of 60 ml/m2 , which has good sensitivity, albeit with low specificity.
Multiple watershed management approaches exist around the world and they are based on various theoretical principles, which most of the time depends on the context of implementation. While many ...countries had adopted national policies enforcing watershed management, theoretical principles tend to be adjusted to meet local specificities. So, an effective theory of watershed management appears at the intersection of public concerns and local social dynamics.Using environmental pragmatism and social strategic analysis, and after the realization of six case studies, we present how the Quebec’s model of watershed management has been affected on a theory point of view by social adjustment processes. This look allow to explain that theoretical marks evolve in some directions, sometimes reinforced or avoided by local actors, or how they become the base for innovation to be consistent with local situations.
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