Inactivation of the Osteopontin Gene Enhances Vascular Calcification of Matrix Gla Protein–deficient Mice: Evidence for Osteopontin as an Inducible Inhibitor of Vascular Calcification In Vivo

Osteopontin (OPN) is abundantly expressed in human calcified arteries. To examine the role of OPN in vascular calcification, OPN mutant mice were crossed with matrix Gla protein (MGP) mutant mice. Mice deficient in MGP alone (MGP−/− OPN+/+) showed calcification of their arteries as early as 2 weeks (wk) after birth (0.33 ± 0.01 mmol/g dry weight), and the expression of OPN in the calcified arteries was greatly up-regulated compared with MGP wild-types. OPN accumulated adjacent to the mineral and colocalized to surrounding cells in the calcified media. Cells synthesizing OPN lacked smooth muscle (SM) lineage markers, SM α-actin and SM22α. However, most of them were not macrophages. Importantly, mice deficient in both MGP and OPN had twice as much arterial calcification as MGP−/− OPN+/+ at 2 wk, and over 3 times as much at 4 wk, suggesting an inhibitory effect of OPN in vascular calcification. Moreover, these mice died significantly earlier (4.4 ± 0.2 wk) than MGP−/− OPN+/+ counterparts (6.6 ± 1.0 wk). The cause of death in these animals was found to be vascular rupture followed by hemorrhage, most likely due to enhanced calcification. These studies are the first to demonstrate a role for OPN as an inducible inhibitor of ectopic calcification in vivo

Age and aneurysm position predict patterns of left ventricular dysfunction after subarachnoid hemorrhage

Cardiac injury, including left ventricular dysfunction, frequently occurs in patients with subarachnoid hemorrhage. Patterns of left ventricular dysfunction often do not follow coronary artery distributions, and may correlate with myocardial sympathetic innervation. Left ventricular dysfunction of the anterior and anteroseptal walls that spares the apex is unusual for patients with myocardial infarction and may represent a neurally mediated pattern of injury. We performed serial echocardiography on 225 patients with subarachnoid hemorrage and classified those with regional wall-motion abnormalities as following either an apex-sparing (AS) or apex-affected (AA) pattern. Wall-motion abnormalities were found in 61 of 225 patients studied (27%). The AS pattern was found in 49% of these patients. Younger age and anterior aneurysm position were independent predictors of this AS pattern. Both patterns of wall-motion abnormalities appear to be transient, reversible phenomena. The AS pattern may represent a unique form of neurally mediated cardiac injury

Prospective analysis of prevalence, distribution, and rate of recovery of left ventricular systolic dysfunction in patients with subarachnoid hemorrhage

Object. Subarachnoid hemorrhage (SAH) has been associated with cardiac injury and left ventricular (LV) dysfunction. The incidence and natural history of neurocardiogenic injury after SAH remains poorly understood. The objective of this study was to describe the incidence, time course, recovery rate, and segmental patterns of LV dysfunction after SAH. Methods. Echocardiography was performed three times over a 7-day period in 173 patients with SAH. The incidence of global (ejection fraction [EF] \u3c 50%) and segmental (any regional wall-motion abnormality [RWMA]) LV dysfunction was measured. The time course of LV dysfunction was determined by comparing the prevalence of LVEF less than 50% and RWMA at 0 to 2, 3 to 5, and 6 to 8 days after SAH. The recovery rate was defined as the proportion of patients with partial or complete normalization of function. The distribution of RWMAs among 16 LV segments was also determined. An LVEF less than 50% was found in 15% of patients, and 13% had an RWMA with a normal LVEF. There was a trend toward increased dysfunction at 0 to 2 days after SAH, compared with 3 to 8 days after SAH. Recovery of LV function was observed in 66% of patients. The most frequently abnormal LV segments were the basal and middle ventricular portions of the anteroseptal and anterior walls. The apex was rarely affected. Conclusions. Left ventricular systolic dysfunction occurs frequently after SAH and usually improves over time. The observed segmental patterns of LV dysfunction often do not correlate with coronary artery distributions

Predictors of Neurocardiogenic Injury after Subarachnoid Hemorrhage

Background and Purpose-Subarachnoid hemorrhage (SAH) frequently results in myocardial necrosis with release of cardiac enzymes. Historically, this necrosis has been attributed to coronary artery disease, coronary vasospasm, or oxygen supply-demand mismatch. Experimental evidence, however, indicates that excessive release of norepinephrine from the myocardial sympathetic nerves is the most likely cause. We hypothesized that myocardial necrosis after SAH is a neurally mediated process that is dependent on the severity of neurological injury. Methods-Consecutive patients admitted with SAH were enrolled prospectively. Predictor variables reflecting demographic (age, sex, body surface area), hemodynamic (heart rate, systolic blood pressure), treatment (phenylephrine dose), and neurological (Hunt-Hess score) factors were recorded. Serial cardiac troponin I measurements and echocardiography were performed on days 1, 3, and 6 after enrollment. Troponin level was treated as a dichotomous outcome variable. We performed univariate and multivariate analyses on the relationships between the predictor variables and troponin level. Results-The study included 223 patients with an average age of 54 years. Twenty percent of the subjects had troponin I levels \u3e1.0 μg/L (range, 0.3 to 50 μg/L). By multivariate logistic regression, a Hunt-Hess score \u3e2, female sex, larger body surface area and left ventricular mass, lower systolic blood pressure, and higher heart rate and phenylephrine dose were independent predictors of troponin elevation. Conclusions-The degree of neurological injury as measured by the Hunt-Hess grade is a strong, independent predictor of myocardial necrosis after SAH. This finding supports the hypothesis that cardiac injury after SAH is a neurally mediated process

Prevalence and implications of diastolic dysfunction after subarachnoid hemorrhage

Introduction: Electrocardiographic changes, troponin release, and reduced left ventricular ejection fractionhavebeen described after subarachnoid hemorrhage (SAH). Little is known about the occurrence of diastolic dysfunction in this setting. The purpose of this study was to determine the prevalence of diastolic dysfunction and its association with cardiac outcomes after SAH. Methods: SAH patients were prospectively enrolled into the study, and echocardiographic, clinical, chest X-ray, and cardiac troponin I data were obtained on days 1, 3, and 6 after enrollment. Each echocardiogram included Doppler recordings of mitral inflow and pulmonary venous flow. For each study, diastolic function was categorized as normal, impaired relaxation, pseudonormal, or restrictive. The relationships between diastolic dysfunction and pulmonary edema-elevated cardiac troponin I and left ventricular contractile dysfunction were quantified using both univariate and multivariate statistical methods. Clinical predictors of diastolic dysfunction were defined by multivariate logistic regression. Results: Of 223 enrolled subjects, 207 had technically adequate Doppler data. Diastolic dysfunction was observed in 71% of subjects. The prevalence of diastolic versus systolic dysfunction in 44 patients with pulmonary edema was 91 versus 37%, respectively (p = 0.001). After multivariate statistical adjustment, diastolic dysfunction remained a significant predictor of pulmonary edema (odds ratio [OR] 3.34, 95% CI = 1.05-10.59). Diastolic dysfunction also was associated with troponin release (p = 0.02). A history of hypertension and increasing age were predictive of diastolic dysfunction. Conclusion: Diastolic dysfunction is common after SAH. It is associated with history of hypertension and older age and may explain the development of pulmonary edema in many SAH patients. Copyright © 2005 Humana Press Inc. All rights of any nature whatsoever are reserved

Plasma B-type natriuretic peptide levels are associated with early cardiac dysfunction after subarachnoid hemorrhage

Background and Purpose - Serum B-type natriuretic peptide (BNP) is elevated after subarachnoid hemorrhage (SAH), as well as in the setting of congestive heart failure and myocardial infarction. The aim of this study was to prospectively quantify the relationship between BNP levels and cardiac outcomes after SAH. Methods - Plasma was collected for BNP measurements as soon as possible after enrollment; a mean of 5±4 days after SAH symptom onset. On days 1, 3, and 6 after enrollment, troponin I (cTi) was measured and 2-dimensional echocardiography was performed. The following cardiac variables were collected and treated dichotomously: left ventricular ejection fraction (LVEF), regional wall motion abnormalities (RWMA), diastolic dysfunction, pulmonary edema, and cTi. Results - There were 57 subjects. The median BNP level was 141 pg/mL (range, 0.8 to 3330 pg/mL). Higher mean BNP levels were present in those with RWMA (550 versus 261 pg/mL; P=0.012), diastolic dysfunction (360 versus 44; P=0.011), pulmonary edema (719 versus 204; P=0.016), elevated cTi (662 versus 240; P=0.004), and LVEF \u3c50% (644 versus 281; P=0.015). Conclusion - Early after SAH, elevated BNP levels are associated with myocardial necrosis, pulmonary edema, and both systolic and diastolic dysfunction of the left ventricle. These findings support the hypothesis that the heart releases BNP into the systemic circulation early after SAH. © 2005 American Heart Association, Inc