Echocardiographic assessment of degenerative mitral stenosis: a diagnostic challenge of an Eemerging cardiac disease

Degenerative mitral stenosis (DMS) is characterized by decreased mitral valve (MV) orifice area and increased transmitral pressure gradient due to chronic noninflammatory degeneration and subsequent calcification of the fibrous mitral annulus and the MV leaflets. The “true” prevalence of DMS in the general population is unknown. DMS predominantly affects elderly individuals, many of whom have multiple other comorbidities. Transcatheter MV replacement techniques, although their long-term outcomes are yet to be tested, have been gaining popularity and may emerge as more effective and relatively safer treatment option for patients with DMS. Echocardiography is the primary imaging modality for evaluation of DMS and related hemodynamic abnormalities such as increased transmitral pressure gradient and pulmonary arterial pressure. Classic echocardiographic techniques used for evaluation of mitral stenosis (pressure half time, proximal isovelocity surface area, continuity equation, and MV area planimetry) lack validation for DMS. Direct planimetry with 3-dimensional echocardiography and color flow Doppler is a reasonable technique for determining MV area in DMS. Cardiac computed tomography is an essential tool for planning potential interventions or surgeries for DMS. This article reviews the current concepts on mitral annular calcification and its role in DMS. We then discuss the epidemiology, natural history, differential diagnosis, mechanisms, and echocardiographic assessment of DMS

Preoperative vitamin K reduces blood transfusions at time of left ventricular assist device implant

Background: Congestive heart failure patients have hepatic congestion and abnormal coagulation profiles, increasing perioperative bleeding at time of ventricular assist device implantation. This study examined the impact of the preoperative administration of vitamin K on perioperative blood transfusion requirements. Methods: Retrospectively, 190 patients met inclusion criteria. Patients received no vitamin K (n = 62) or two 10-mg doses of intravenous vitamin K (n = 128) in the 24 hours before assist device implantation. Primary end points included transfusion requirements and reexploration rates for bleeding. Secondary outcomes were pump thrombosis and in-hospital mortality. Results: Baseline characteristics were similar between the 2 groups, with slight differences (not statistically significant) noted in the Interagency Registry for Mechanically Assisted Circulatory Support profile and total bilirubin levels. The only significant difference noted was the year of implantation (

Retrograde venous perfusion with hypothermic saline and adenosine for protection of the ischemic spinal cord

Purpose: Spinal cord injury and the resultant postoperative paraplegia are devastating complications of thoracic aortic surgery, for which no widely accepted protective interventions exist. We hypothesized that retrograde venous perfusion-cooling of the spinal cord with a hypothermic saline and adenosine solution would protect it from ischemic injury caused by thoracic aortic occlusion

Preservation of intercostal arteries during thoracoabdominal aortic aneurysm surgery: A retrospective study

Objective: The purpose of this article was to examine the influence of reimplantation of patent intercostal and lumbar arteries on the incidence of postoperative paraplegia/paraparesis in patients undergoing clamp-and-sew surgical repair of thoracoabdominal aortic aneurysms, Methods: Data from January 1987 through December 1997 were retrospectively collected on 132 patients. Ninety-one patients in group I underwent aneurysm repairs before January 1995 and did not undergo intercostal artery reimplantation, Group II included the more recent 41 patients who had vessels between the eighth thoracic intercostal and the second lumbar arteries reimplanted to the graft or preserved at the aortic anastomoses, Results: The operative mortality rate was 13.2% (12/91) in group I and 4.9% (2/41) in group n: (P = .22), The incidence of postoperative paraplegia was significantly lower in the more recent cohort of patients (8.8% [8/91] in group I vs 0% [0/41] in group II, P = .05). The overall rate of spinal cord dysfunction was lowered from 9.9% (9/91) in group I to 2.4% (1/41) in group II (P = .17). However, a multivariable logistic regression analysis identified only aneurysm extent (Crawford type I and type II) as a predictor of less postoperative spinal cord injury (P = .08). The average aortic crossclamp time in group I was 30.3 +/- 11.5 (SD) minutes, and the time of aortic occlusion in group II was not significantly prolonged,,vith an average crossclamp time of 31.0 +/- 21.0 (SD) minutes (P = .88). Conclusions: An aggressive approach to maintain intercostal artery patency during clamp-and-sew repair of thoracoabdominal aortic aneurysms may effectively lower the incidence of spinal cord injury without prolonging aortic crossclamp time

The Wall Street Walk when Blockholders Compete for Flows

An important recent theoretical literature argues that the threat of exit can represent an effective form of governance when the blockholder is a principal. However, a significant fraction of equity blocks is held by delegated portfolio managers. How do agency frictions arising from the delegation of portfolio management affect the ability of blockholders to govern via the threat of exit? We show that when blockholders are sufficiently career concerned exit will fail as a disciplining device. Our results have testable implications on the relative degree to which different classes of delegated portfolio managers use exit as a form of governance