Quantitative perfusion imaging assessing acquired discrete peripheral pulmonary artery stenosis.

We present the case an 8-yr-old boy evaluated for anastomotic stenosis of the right pulmonary artery after surgical repair of hemitruncus at 6 wk of age. Pulmonary angiography revealed only mild narrowing and a 10-mm pressure gradient across the anastomosis, but quantitative perfusion imaging demonstrated that the right lung only received 16% of pulmonary blood flow. Subsequently, balloon angioplasty of the anastomotic site was performed, resulting in complete resolution of the stenosis and gradient.

Potentially serious drug interactions secondary to high-dose diltiazem used in the treatment of pulmonary hypertension.

Two patients had potentially serious drug interactions (phenytoin, digoxin) that were probably attributable to changes in pharmacokinetics and pharmacodynamics caused by high-dose calcium channel blocker therapy (diltiazem) in the treatment of pulmonary hypertension. Even in the approved normal dosages for the treatment of angina and hypertension, calcium channel blockers are known to cause significant changes in the metabolism of other drugs. Currently, no data exist on the effects of the very high dosages of these drugs, administered to patients with pulmonary hypertension, on the metabolism and clearance of other agents, although, based on our experience and literature reports, recommendations for monitoring therapy can be made.

Functional implications of the pulmonary microcirculation. An update.

The microscopic anatomy of the pulmonary circulation was reviewed, comparing the evidence for two competing models, the sheet-and-post paradigm and the tubular paradigm. Implications of the two paradigms were analyzed for function, including flow, recruitment, distension, and diffusion. We conclude that the pulmonary microcirculation is not essentially different from the systemic microcirculation except that two layers of tubular capillaries are arranged on a central layer of connective tissue, the alveolar wall.

Surgical repair of anatomically corrected malposition of the great arteries.

Anatomically corrected malposition of the great arteries is a rare malformation in which the aorta and pulmonary artery arise from their appropriate ventricles but in an abnormal spatial relationship. This report describes 2 patients with anatomically corrected malposition who underwent closure of a ventricular septal defect and placement of a right ventricle-pulmonary artery conduit. A review of the literature indicates that surgical results have been good (92% survival) in those patients with situs solitus and atrioventricular concordance [S,D,L].

Doppler pressure gradient estimation in children. Accuracy, effect of activity and exercise, and the need for sedation during examination.

Noninvasive estimation of pressure drop has been shown to be an accurate and useful application of Doppler echocardiography. Most accuracy series have used patient-sedated catheterization gradient measurements as the standard of reference. Doppler gradient estimates, however, are commonly made without sedation of the patient when hemodynamics may differ from those present at catheterization.