Changes in systemic and pulmonary blood flow distribution in normal adult volunteers in response to posture and exercise: a phase contrast magnetic resonance imaging study.

Hemodynamics are usually evaluated in the supine position at rest. This is only a snapshot of an individual's daily activities. This study describes circulatory adaptation, as assessed by magnetic resonance imaging, to changes in position and exercise. Phase contrast magnetic resonance imaging of blood flow within systemic and pulmonary arteries and veins was performed in 24 healthy volunteers at rest in the prone and supine position and with bicycle exercise in the supine position. No change was seen in systemic blood flow when moving from prone to supine. Exercise resulted in an increased percentage of cardiac output towards the lower body. Changes in position resulted in a redistribution of blood flow within the left lung--supine positioning resulted in decreased blood flow to the left lower pulmonary vein. With exercise, both the right and left lower lobes received increased blood flow, while the upper lobes received less.

Effectiveness of serial increases in amino-terminal pro-B-type natriuretic peptide levels to indicate the need for mechanical circulatory support in children with acute decompensated heart failure.

We sought to determine prospectively whether serial assessment of the natriuretic peptide prohormone, amino-terminal pro-B-type natriuretic peptide (NT-pro-BNP), correlated with clinical severity and outcomes in children hospitalized for acute decompensated heart failure (ADHF). Patients (>1 month of age) admitted from 2005 to 2007 with ADHF requiring intravenous vasoactive/diuretic therapy for ADHF were eligible. Serum NT-pro-BNP levels were obtained within 24 hours of admission and at prespecified intervals, and clinical caregivers were blinded to these levels. End points included hospital discharge, death or cardiac transplantation, and care escalation including the need for mechanical circulatory support (MCS) was noted. Twenty-four patients were enrolled: 22 survived to hospital discharge and 2 died. Ten required MCS (of which 6 underwent cardiac transplantation). Two patients underwent transplantation without MCS. For the entire cohort, NT-pro-BNP levels peaked at days 2 to 3 after admission, with a subsequent gradual decrease until discharge. However, for those who did require MCS, NT-pro-BNP failed to decrease consistently until after MCS initiation. At discharge, NT-pro-BNP levels were significantly decreased from admission levels but remained well above normal for all patients. Single-point NT-pro-BNP levels on admission did not correlate with independently assessed clinical scores of heart failure severity or predict the need for MCS in this cohort. In conclusion, serial NT-pro-BNP levels demonstrated an incremental trend after 48 hours in patients who went on to require MCS but decreased in all other patients and may therefore assist the decision to initiate or avoid MCS after admission for pediatric ADHF.

Transpleural pulmonary-to-systemic venous collaterals in a case with obstructed scimitar vein.

Scimitar syndrome is a rare cause of left-to-right shunting. Surgery is indicated for a pulmonary-to-systemic blood flow ratio greater than 1.5:1 and not infrequently is complicated by postoperative obstruction. This report presents a case of scimitar syndrome and reviews how magnetic resonance imaging (MRI) can be used for initial and follow-up assessment of the syndrome with emphasis on suspected pulmonary venous obstruction. Given the potential high incidence of postoperative occlusion, MRI provides hemodynamic and anatomic information for both initial and follow-up assessment of scimitar syndrome. MRI clearly demonstrated transpleural pulmonary-to-systemic venous collaterals draining the obstructed scimitar vein.

Implantation of drug-eluting stents for relief of obstructed infra-cardiac totally anomalous pulmonary venous connection in isomerism of the right atrial appendages.

We describe an infant with severe obstruction of infra-cardiac totally anomalous pulmonary venous connection associated with right isomerism, atrioventricular septal defect, pulmonary atresia, and multiple aortopulmonary collateral arteries. Implantation of a stent into the obstructed descending vertical vein provided effective palliation, with a dramatic increase in saturations of oxygen obviating the need for urgent high-risk surgery.