Abnormal pulmonary artery stiffness in pulmonary arterial hypertension: in vivo study with intravascular ultrasound.

Background: There is increasing recognition that pulmonary artery stiffness is an important determinant of right ventricular (RV) afterload in pulmonary arterial hypertension (PAH). We used intravascular ultrasound (IVUS) to evaluate the mechanical properties of the elastic pulmonary arteries (PA) in subjects with PAH, and assessed the effects of PAH-specific therapy on indices of arterial stiffness.

Method: Using IVUS and simultaneous right heart catheterisation, 20 pulmonary segments in 8 PAH subjects and 12 pulmonary segments in 8 controls were studied to determine their compliance, distensibility, elastic modulus and stiffness index β.

The relationship between pulmonary artery and pulmonary capillary wedge pressure for the diagnosis of pulmonary vascular disease.

Background: Left heart disease and pulmonary vascular disease (PVD) both lead to raised pulmonary artery pressure (PAP) but differ in pathophysiology, prognosis and treatment. There are currently no criteria for diagnosing PVD in the presence of left heart disease. We therefore studied the relationship between PAP and pulmonary capillary wedge pressure (PCWP, a measure of left atrial pressure) to help define when PAP should be considered 'out-of-proportion' to PCWP, thus suggestive of PVD.

Determinants of coronary arterial flow-mediated dilatation following percutaneous coronary intervention.

Objective: It has previously been observed that coronary diameter may increase following relief of flow-limiting obstruction. Flow mediated dilatation (FMD) is a fundamental adaptive mechanism for arteries, which is dependent on intact endothelial function. We thus aimed to characterize whether the degree of this flow-mediated dilatation was related to risk factors, which may impair endothelial function.