Jack superpolynomials with negative fractional parameter: clustering properties and super-Virasoro ideals

The Jack polynomials P_\lambda^{(\alpha)} at \alpha=-(k+1)/(r-1) indexed by certain (k,r,N)-admissible partitions are known to span an ideal I^{(k,r)}_N of the space of symmetric functions in N variables. The ideal I^{(k,r)}_N is invariant under the action of certain differential operators which include half the Virasoro algebra. Moreover, the Jack polynomials in I^{(k,r)}_N admit clusters of size at most k: they vanish when k+1 of their variables are identified, and they do not vanish when only k of them are identified. We generalize most of these properties to superspace using orthogonal eigenfunctions of the supersymmetric extension of the trigonometric Calogero-Moser-Sutherland model known as Jack superpolynomials. In particular, we show that the Jack superpolynomials P_{\Lambda}^{(\alpha)} at \alpha=-(k+1)/(r-1) indexed by certain (k,r,N)-admissible superpartitions span an ideal {\mathcal I}^{(k,r)}_N of the space of symmetric polynomials in N commuting variables and N anticommuting variables. We prove that the ideal {\mathcal I}^{(k,r)}_N is stable with respect to the action of the negative-half of the super-Virasoro algebra. In addition, we show that the Jack superpolynomials in {\mathcal I}^{(k,r)}_N vanish when k+1 of their commuting variables are equal, and conjecture that they do not vanish when only k of them are identified. This allows us to conclude that the standard Jack polynomials with prescribed symmetry should satisfy similar clustering properties. Finally, we conjecture that the elements of {\mathcal I}^{(k,2)}_N provide a basis for the subspace of symmetric superpolynomials in N variables that vanish when k+1 commuting variables are set equal to each other.Comment: 36 pages; the main changes in v2 are : 1) in the introduction, we present exceptions to an often made statement concerning the clustering property of the ordinary Jack polynomials for (k,r,N)-admissible partitions (see Footnote 2); 2) Conjecture 14 is substantiated with the extensive computational evidence presented in the new appendix C; 3) the various tests supporting Conjecture 16 are reporte

Delay from Diagnosis to Surgery in Transferred Type A Aortic Dissection

Objectives: The purpose of this research is to analyze factors associated with delays to surgical management of Type A acute aortic dissection patients. Methods: Time from diagnosis to surgery and associated factors were evaluated in 1880 surgically managed Type A dissection patients enrolled in the International Registry of Acute Aortic Dissection. Results: The majority of patients were transferred (75.7% vs 24.3%). Patients who were transferred had a median delay from diagnosis to surgery of 4.0 hours (interquartile range 2.5-7.2 hours), compared with 2.3 hours (interquartile range 1.1-4.2 hours; P < .001) in nontransferred patients. Among patients who were transferred, those with worst-ever, posterior, or tearing chest pain those with severe complications, and those receiving transthoracic echocardiogram prior to a transesophageal echocardiogram or as the only echocardiogram were treated more quickly. Those undergoing magnetic resonance imaging, or who had prior cardiac surgery, had longer delays to surgery. Among nontransferred patients, those with coma were treated more quickly. In both groups, patients presenting with emergent conditions such as cardiac tamponade, hypotension, or shock had more rapid treatment. Among transferred patients, surviving patients had longer delays (4.1 [2.6-7.8] hours vs 3.3 [2.0-6.0] hours, P = .001). Overall mortality did not differ between patients who were transferred vs not (19.3% vs 21.1%, P = .416). Conclusion: Simply being transferred added significantly to the delay to surgery for Type A acute aortic dissection patients, but a number of factors affected its extent. Overall, signs and symptoms leading to a definitive diagnosis or indicating immediate life threat reduced time to surgery, while factors suggesting other diagnoses correlated with delays

Influence of clinical presentation on the outcome of acute B aortic dissection : evidences from IRAD

In-hospital outcome of acute type B dissection (ABAD) is strongly related to preoperative aortic conditions. In order to clarify the influence of the clinical presentation on the outcome, we analyzed the patients of the International Registry of Acute Aortic Dissection (IRAD). All patients affected by complicated ABAD, enrolled in the IRAD from 1996-2004, were included. Complications were defined as the presence of shock, periaortic hematoma, spinal cord ischemia, preoperative mesenteric ischemia/infarction, acute renal failure, limb ischemia, recurrent pain, refractory pain or refractory hypertension (group I). All other patients were categorized as uncomplicated (group II). A comprehensive analysis was performed of all clinical variables in relation to in-hospital outcome

The role of age in complicated acute type B aortic dissection

Background Complicated acute type B aortic dissection (cABAD) generally requires urgent intervention. Advanced age is a risk factor for mortality after thoracic aortic intervention, including surgery for aortic dissection. The purpose of this study was to investigate the exact impact of increasing age on the management and outcomes of cABAD. Methods We analyzed the outcomes of 583 patients with cABAD enrolled in the International Registry of Acute Aortic Dissection (IRAD) between 1996 and 2012. All patients with cABAD were categorized according to age by decade and management type (medical, surgical, or endovascular treatment), and outcomes were subsequently investigated in the different age groups. Results The mean age of the cohort was 63.4 \ub1 14.2 years, 36% of patients (n = 209) were greater than 70 years of age and 64% (n = 374) were less than 70 years. The utilization of surgery and endovascular techniques progressively decreased with patient age, while the rate of medical management significantly increased with age (p < 0.001). The in-hospital mortality rates for complicated patients younger than 70 years versus 70 years or more were 10.1% versus 30.0% for endovascular treatment (p = 0.001), 17.2% versus 34.2% for surgical treatment (p = 0.027), and 14.2% versus 32.2% for medical treatment (p = 0.001). Age 70 years or greater was a predictor of in-hospital mortality in multivariate analysis (odds ratio 2.37, 95% confidence interval: 1.23 to 4.54, p = 0.010). Conclusions Advanced age has a dramatic impact on the management and outcomes of patients with cABAD. A nonsignificant trend toward lower mortality after endovascular management was observed, both for younger patients and for elderly patients

Ascending thoracic aorta dimension and outcomes in acute type B dissection (from the international registry of acute aortic dissection [IRAD])

It is not well known if the size of the ascending thoracic aorta at presentation predicts features of presentation, management, and outcomes in patients with acute type B aortic dissection. The International Registry of Acute Aortic Dissection (IRAD) database was queried for all patients with acute type B dissection who had documentation of ascending thoracic aortic size at time of presentation. Patients were categorized according to ascending thoracic aortic diameters 644.0, 4.1 to 4.5, and <4.6 cm. Four hundred eighteen patients met inclusion criteria; 291 patients (69.6%) were men with a mean age of 63.2 \ub1 13.5 years. Ascending thoracic aortic diameter 644.0 cm was noted in 250 patients (59.8%), 4.1 to 4.5 cm in 105 patients (25.1%), and <4.6 cm in 63 patients (15.1%). Patients with an ascending thoracic aortic diameter <4.6 cm were more likely to be men (p = 0.01) and have Marfan syndrome (p <0.001) and known bicuspid aortic valve disease (p = 0.003). In patients with an ascending thoracic aorta <4.1 cm, there was an increased incidence of surgical intervention (p = 0.013). In those with an ascending thoracic aorta <4.6 cm, the root, ascending aorta, arch, and aortic valve were more often involved in surgical repair. Patients with an ascending thoracic aorta 644.0 were more likely to have endovascular therapy than those with larger ascending thoracic aortas (p = 0.009). There was no difference in overall mortality or cause of death. In conclusion, ascending thoracic aortic enlargement in patients with acute type B aortic dissection is common. Although its presence does not appear to predict an increased risk of mortality, it is associated with more frequent open surgical intervention that often involves replacement of the proximal aorta. Those with smaller proximal aortas are more likely to receive endovascular therapy

Acute type B aortic dissection : does aortic arch involvement affect management and outcomes? Insights from the International Registry of Acute Aortic Dissection (IRAD)

BACKGROUND - Stanford Type B acute aortic dissection (TB-AAD) spares the ascending aorta and is optimally managed with medical therapy in the absence of complications. However, the treatment of TB-AAD with aortic arch involvement (AAI) remains an unresolved issue. METHODS AND RESULTS - We examined 498 patients with TB-AAD enrolled in the International Registry of Acute Aortic Dissection (IRAD) between 1996 and 2003. Kaplan-Meier mortality curves were constructed and multivariate regression models were performed to identify independent predictors of AAI and to evaluate whether AAI was an independent predictor of follow-up mortality. We found that 371 (74.5%) patients with TB-AAD did not have AAI versus 127 (25.5%) with AAI. Independent predictors of AAI were a history of previous aortic surgery (OR 3.4; 95% CI, 1.6 to 7.6; P=0.002), absence of back pain (OR 1.6; 95% CI, 1.1 to 2.5; P=0.05), and any pulse deficit (1.9; 95% CI, 1.1 to 3.3, P=0.03). Mortality for patients without AAI was 9.4%\ub14.3% and 21.0%\ub16.9% at 1 and 3 years versus 9.2%\ub17.7% and 19.9%\ub111.1% with AAI, respectively (mean follow-up overall, 2.3 years, log rank P=0.82). AAI was not an independent predictor of long-term mortality. CONCLUSIONS - Patients with TB-AAD and aortic arch involvement do not differ with regards to mortality at 3 years. Whether or not AAI involvement impacts other measures of morbidity such as freedom from operation or endovascular intervention deserves further study