Saphenous vein grafts display poor endothelium-dependent and endothelium-independent dilation--implications for the pathogenesis of vein graft atherosclerosis.

Objective: As endothelial dysfunction has been implicated in the pathogenesis of late failure of saphenous vein grafts (SVG), we assessed endothelium-dependent and endothelium-independent vascular responses of SVG in humans.

Methods: Subjects undergoing angiography after bypass grafting had selective infusions of acetylcholine (ACh, an endothelium-dependent dilator) and sodium-nitroprusside (SNP, an endothelium-independent dilator) into a non-obstructed vein graft. SVG diameters were measured by quantitative coronary angiography.

Treatment of obstructive sleep apnoea leads to enhanced pulmonary vascular nitric oxide release.

Background: Obstructive sleep apnoea (OSA) is associated with pulmonary hypertension, however neither the pathogenesis of pulmonary vascular disease nor the effect of successful treatment of OSA on pulmonary vascular physiology has been characterised.

Methods: Seven subjects aged 52 (range 36-63) years with moderate to severe obstructive sleep apnoea (apnoea-hypopnoea index>15/h) had detailed pulmonary vascular reactivity studies, before and after 3 months of successful treatment with nasal continuous positive airways pressure (CPAP). On both occasions, we measured pulmonary pressure, flow velocity, flow and resistance, at baseline and in response to acetylcholine (an endothelium-dependent dilator), sodium nitroprusside (an endothelium-independent dilator), l-NMMA (an antagonist of nitric oxide synthesis) and l-Arginine (the substrate of nitric oxide).

Safety of coronary angioplasty to chronic total occlusions.

Percutaneous transluminal coronary angioplasty (PTCA) of chronic total occlusions (CTO) is not performed routinely in some centres due to concerns of low procedural success rates and high rates of short-term complications. This retrospective study examines the safety of PTCA to CTO in 100 consecutive cases compared to 100 matched controls. Success rate was 79% for CTO versus 98% for controls (p<0.

Coronary collateralization: determinants of adequate distal vessel filling after arterial occlusion.

Background: The protective effect of collateral vessels in coronary artery disease (CAD) is well established. Little is known, however, about factors that influence collateral formation.

Methods: We studied the coronary angiograms of 200 consecutive patients with single-vessel coronary artery occlusion.