William T. Moore

Outcome-based anatomic criteria for defining the hostile aortic neck

OBJECTIVE There is abundant evidence linking hostile proximal aortic neck anatomy to poor outcome after endovascular aortic aneurysm repair (EVAR), yet the definition of hostile anatomy varies from study to study. This current analysis was undertaken to identify anatomic criteria that are most predictive of success or failure at the aortic neck after EVAR. METHODS The study group comprised 221 patients in the Aneurysm Treatment using the Heli-FX Aortic Securement System Global Registry (ANCHOR) clinical trial, a population enriched with patients with challenging aortic neck anatomy and failure of sealing. Imaging protocols were not protocol specified but were performed according to the institutions standard of care. Core laboratory analysis assessed the three-dimensional centerline-reformatted computed tomography scans. Failure at the aortic neck was defined by type Ia endoleak occurring at the time of the initial endograft implantation or during follow-up. Receiver operating characteristic curve analysis was used to assess the value of each anatomic measure in the classification of aortic neck success and failure and to identify optimal thresholds of discrimination. Binary logistic regression was performed after excluding highly intercorrelated variables, creating a final model with significant predictors of outcome after EVAR. RESULTS Among the 221 patients, 121 (54.8%) remained free of type Ia endoleak and 100 (45.2%) did not. Type Ia endoleaks presented immediately after endograft deployment in 58 (58.0%) or during follow-up in 42 (42.0%). Receiver operating characteristic curve analysis identified 12 variables where the classification of patients with type Ia endoleak was significantly more accurate than chance alone. Increased aortic neck diameter at the lowest renal artery (P = .013) and at 5 mm (P = .008), 10 mm (P = .008), and 15 mm (P = .010) distally; aneurysm sac diameter (P = .001), common iliac artery diameters (right, P = .012; left, P = .032), and a conical (P = .049) neck configuration were predictive of endoleak. By contrast, increased aortic neck length (P = .050), a funnel-shaped aortic neck (P = .036), and neck mural thrombus content, as measured by average thickness (P = .044) or degrees of circumferential coverage (P = .029), were protective against endoleak. Binary logistic regression identified three variables independently predictive of type Ia endoleak. Neck diameter at the lowest renal artery (P = .002, cutpoint 26 mm) and neck length (P = .017, cutpoint 17 mm) were associated with endoleak, whereas some mural neck thrombus content was protective (P = .001, cutpoint 11° of circumferential coverage). CONCLUSIONS A limited number of independent anatomic variables are predictive of type Ia endoleak after EVAR, including aortic neck diameter and aortic neck length, whereas mural thrombus in the neck is protective. This study suggests that anatomic measures with identifiable threshold cutpoints should be considered when defining the hostile aortic neck and assessing the risk of complications after EVAR.

Predicting the duration and reversal probability of leveraged buyouts

Abstract We examine the probability that a firm will return to public status following a leveraged buyout (LBO) transaction and for those LBOs that will eventually reverse, we examine the factors that impact the timing of the reversal. These two dimensions of the reversal decision are studied by estimating standard and split population hazard models for a sample of 343 LBO transactions. Our results indicate that not all LBO firms eventually will reverse, i.e. the net benefits of private status for some firms appear to be permanent. For those LBOs that will reverse, reversal probabilities are found to increase over the first seven or eight years following a typical LBO, then to decline thereafter.

Small Molecule Kaempferol Promotes Insulin Sensitivity and Preserved Pancreatic β-Cell Mass in Middle-Aged Obese Diabetic Mice

Insulin resistance and a progressive decline in functional β-cell mass are hallmarks of developing type 2 diabetes (T2D). Thus, searching for natural, low-cost compounds to target these two defects could be a promising strategy to prevent the pathogenesis of T2D. Here, we show that dietary intake of flavonol kaempferol (0.05% in the diet) significantly ameliorated hyperglycemia, hyperinsulinemia, and circulating lipid profile, which were associated with the improved peripheral insulin sensitivity in middle-aged obese mice fed a high-fat (HF) diet. Kaempferol treatment reversed HF diet impaired glucose transport-4 (Glut4) and AMP-dependent protein kinase (AMPK) expression in both muscle and adipose tissues from obese mice. In vitro, kaempferol increased lipolysis and prevented high fatty acid-impaired glucose uptake, glycogen synthesis, AMPK activity, and Glut4 expression in skeletal muscle cells. Using another mouse model of T2D generated by HF diet feeding and low doses of streptozotocin injection, we found that kaempferol treatment significantly improved hyperglycemia, glucose tolerance, and blood insulin levels in obese diabetic mice, which are associated with the improved islet β-cell mass. These results demonstrate that kaempferol may be a naturally occurring anti-diabetic agent by improving peripheral insulin sensitivity and protecting against pancreatic β-cell dysfunction.

Equity valuation effects of forming master limited partnerships

Abstract Equity valuation effects of decisions by corporations to shift assets to master limited partnerships (MLPs) are examined for the period 1982–1987. Positive average abnormal returns are found for (1) total conversions of corporations to MLPs (5.89%), (2) rollouts of subsets of assets by distribution of MLP equity claims to parent-firm shareholders (6.41%), and (3) rollouts of subsets of assets by public sale of MLP equity claims (2.41%). The positive effects are consistent with tax advantages, reduction in free cash flow, and information signaling. The positive effects for rollouts of subsets of assets are also consistent with reductions in information asymmetry and improvements in asset management.

Dismantling internal capital markets via spinoff: effects on capital allocation efficiency and firm valuation

Abstract We investigate the linkage between changes in firm value and changes in capital allocation efficiency resulting from dismantling internal capital markets via spinoffs. We find no evidence of wholesale misallocation of capital pre-spinoff. On the average, excess value increases following spinoffs. Furthermore, changes in excess value are positively linked to changes in capital allocational efficiency following spinoff. We find that spinoff announcement returns are greater (smaller) when the parent allocates capital to the unit to be spun off in a seemingly less (more) efficient manner. Divested division capital expenditures move toward industry levels after spinoff, regardless of their relative investment opportunities.

Timing of Convertible Debt Issues

Abstract The popularity of convertible debt as a financing vehicle waxes and wanes. In this article, we investigate whether the timing of convertible debt issues can be explained by three reported reasons for its use as a financing vehicle. Specifically, we reexamine the long-standing beliefs that convertibles are used as “debt sweeteners” and there are “hot issue” markets for these securities. In addition, we examine whether convertibles help diminish the agency conflict between bondholders and stockholders as suggested by Brennan and Schwartz (1988) . Our empirical results suggest that: (1) corporate managers issue convertible debt as debt sweeteners and (2) more convertible debt is issued in hot markets.

Stock vs. stock-warrant units: evidence from seasoned offerings

Abstract Recent theories based on sequential financing and information signaling reveal a special role for warrants. Data from initial public offerings (IPOs) of stock-warrant units have been used to test the theories, and we extend the analysis to seasoned offerings. Consistent with predictions from both families of theories, we find that issues made by smaller and younger firms are more likely to involve stock-warrant units, and firms with greater stock price volatility are more likely to issue units in seasoned offerings. Moreover, firms with relatively high levels of long-term debt, and those whose issues are underwritten by less prestigious underwriters are more likely to employ stock-warrant unit financing. Consistent with information signaling, we find that firms with high managerial ownership are more likely to issue units. Firms that include warrants in their stock offerings are predicted to have experienced higher abnormal stock returns than if they had issued shares alone. Thus, consistent with both theoretical explanations, some firms can reduce capital costs by adding warrants to shares in seasoned offerings.

Iatrogenic vascular injury during peripheral revascularization

Iatrogenic vascular injury may occur during peripheral revascularization procedures secondary to the application of vascular occlusive devices. This review summarizes the known mechanical causes of such injury, relates this to clamp design, and suggests methods to minimize such injury by appropriate selection and handling of vascular occlusive clamps.

Analysis of EndoAnchors for endovascular aneurysm repair by indications for use.

OBJECTIVE The proximal aortic neck remains one of the challenges of endovascular aneurysm repair (EVAR), and the risk of type Ia endoleak and endograft migration is increased in patients with short, large-diameter, or highly angulated necks. EndoAnchors have been used as an adjunct to EVAR in such patients, and the aim of this study was to assess their benefit analyzed by indication for use. METHODS During a 2-year period, 319 patients were enrolled at 43 sites in the Aneurysm Treatment Using the Heli-FX Aortic Securement System Global Registry (ANCHOR) study. This prospective, multinational, real-world analysis of EndoAnchors comprised two groups of patients, those undergoing first-time EVAR (primary arm, 242) and those with proximal neck complications remote from the time of an initial endograft implantation (revision arm, 77). The primary arm was further subdivided into patients undergoing prophylactic EndoAnchor use for hostile proximal neck anatomy (178), with a type Ia endoleak evident during initial endograft deployment (60), and in conjunction with extender cuffs after unsatisfactory endograft deployment distally in the neck (four). The revision arm was subdivided into patients presenting with a type Ia endoleak alone (45), endograft migration alone (11), and migration with endoleak (21). Technical success was site reported as satisfactory deployment of the desired number of EndoAnchors without fracture or loss of integrity. Procedural success was defined as technical success without type Ia endoleak at completion arteriography. Core laboratory analysis was performed on 249 baseline and 192 follow-up computed tomographic studies, 66 of which were available within the 1-year window. RESULTS Technical and procedural success rates were highest in the prophylactically treated subset (172 of 178; 96.6%). Whereas the technical success of EndoAnchor deployment was also high in the other subsets, residual type Ia endoleaks were more frequent at completion angiography when the indication for EndoAnchor use was type Ia endoleak, both in the primary arm (17 of 60; 28%) and in the revision arm (9 of 45; 20%). During a median imaging follow-up of 7 months, 183 of 202 patients (90.1%) remained free of type Ia endoleaks. Primary prophylactic patients were free from type Ia endoleak in 110 of 114 cases (96.5%). The most challenging subset was revision patients treated for type Ia endoleak; type Ia endoleaks were evident during follow-up in 10 of 29 of the cases (34%). Sac regression >5 mm in patients with 1-year imaging was observed in 26 of 66 patients (39%) and was highest in the primary prophylaxis subset (20 of 43; 47%). CONCLUSIONS EndoAnchor implantation can be a useful adjunct to EVAR as prophylaxis against proximal attachment site complications in patients with hostile aortic neck anatomy, as treatment for early and late type Ia endoleaks, or, in conjunction with aortic extension cuffs, for endograft migration. Whereas the most challenging patients are those who present with type Ia endoleaks remote from initial EVAR, EndoAnchors are still effective in treating the majority of these cases.

Investment Decisions under Uncertainty: Application of Estimation Risk in the Hillier Approach

In a seminal paper in 1963, Frederick S. Hillier alerted the finance community to the importance of including probabilistic information in the process of investment decision-making [4]. The method proposed and demonstrated by Hillier introduced the use of additional information regarding the probability distributions governing three measures of investment merit: present worth; internal rate of return; and uniform annual cost. He showed that by assessing investment merit only on the basis of a measure of central tendency, crucial information regarding dispersion, hence risk, was ignored and investments were not evaluated accurately. By incorporating the amount of risk involved in terms of the probability distribution of the present worth, the internal rate of return, or uniform annual cost, a firms management can make more sound decisions regarding risky investment proposals. Since this important paper was published, a virtual revolution has occurred in finance, particularly in the area of risk assessment. Indeed, under modern capital asset pricing theory, the dispersion in the probability distribution of future cash flows is an irrelevant statistic. Instead, as the theory goes, a projects systematic risk, as indexed by its “beta,†is the only relevant measure of risk. This disparity between modern capital asset pricing theory and the type of analysis that follows from the Hillier approach will be addressed in detail in Section III. We will show that under conditions in which dispersion is regarded as the relevant measure of risk, the Hillier approach provides a reasonable approximation of the dispersion arising from the multiperiod framework.