Plasma endothelin and early coronary endothelial dysfunction in recipients of a cardiac transplant.

Serotonin constricts coronary arteries with endothelial dysfunction, possibly through reduced endothelial release of nitric oxide or enhanced production of constricting factors such as endothelin. Because the plasma levels of this peptide are increased in the early months after cardiac transplantation, we assessed whether a coronary hypersensitivity to the vasoconstrictor effect of serotonin is associated with high plasma endothelin levels. One to 3 months after cardiac transplantation, serotonin (1, 10, or 20 micrograms/min for 2.5 min each) was infused into the coronary circulation in 32 patients. Changes in coronary diameters were determined by quantitative angiography. A > or = 40% reduction in coronary diameter for a dose of serotonin < or = 10 micrograms/min was observed in group A (n = 14) whereas in group B (n = 18), this diameter reduction was never reached even for a 20 micrograms/min infusion of serotonin. Plasma endothelin levels were significantly higher (p < 0.01) in the coronary ostium and coronary sinus in group A, at 23.4 +/- 1.3 pg/ml and 24.9 +/- 0.9 pg/ml versus 12.6 +/- 0.9 pg/ml and 13.8 +/- 1.1 pg/ml, respectively, in group B. These endothelin levels did not significantly change after intracoronary infusion of serotonin. A significant correlation was found between plasma endothelin levels in the coronary ostium and peak coronary constriction (percentage diameter reduction) in both groups (r = 0.77 for group A and r = 0.92 for group B). Thus, early after cardiac transplantation, serotonin-induced coronary constriction is a common finding, and the severity of this abnormality seems to be influenced by plasma endothelin levels.

Endothelial function of internal mammary artery in patients with coronary artery disease and in cardiac transplant recipients.

The objective of this study was to examine the endothelial function of internal mammary artery in patients with coronary artery disease and in heart transplant recipients. Therefore the response of this artery to increasing concentrations of acetylcholine (1, 10, 20 microg/min for 2.5 minutes each) was assessed in 6 patients in a control group, 16 patients with coronary artery disease (CAD group) matched for risk factors with 16 heart graft recipients (who underwent transplantation for nonischemic heart failure), and 12 patients with coronary artery disease and peripheral vascular disease (PVD group). Diameters of proximal and middle segments of internal mammary artery were measured by quantitative angiography. The responses to the first concentration of acetylcholine were attenuated in these three groups compared with the control group. At the highest concentration of acetylcholine the diameter increase was similar in the control and CAD groups, whereas the responses remained significantly impaired in the transplant and PVD groups. However, after selective infusion of L-arginine (30 mg/min for 11 minutes), the precursor of endothelium-derived nitric oxide, was performed, the responses to acetylcholine were restored in these two latter groups. Endothelin plasma levels were significantly enhanced in the PVD group, which exhibited the most severe impairment in acetylcholine-induced vasodilation. Thus some patients with CAD, mainly those with advanced atherosclerosis, and cardiac transplant recipients exhibit internal mammary artery endothelial dysfunction, and this abnormality seems reversible.

Occluding aortic endoluminal stent graft combined with extra-anatomic axillofemoral bypass as alternative management of abdominal aortic aneurysms for patients at high risk with complex anatomic features: a preliminary report.

PURPOSE: To describe an exclusion endoluminal technique for management of abdominal aortic aneurysms among high-risk patients with complex anatomic features. METHODS: From January 1995 to December 1996, among 143 patients with infrarenal abdominal aortic aneurysm treated by means of endograft placement, 9 (6.3%) had complex aortic or aortoiliac morphologic features. For these patients, the endograft was delivered through a femoral cutdown in an occluding aortoiliac configuration. The contralateral iliac artery was occluded with an iliac endograft. Axillofemoral bypass grafting was performed. Computed tomographic scans were obtained regularly. RESULTS: There was 1 postoperative death of severe arrhythmia. All aneurysms were found to be affected by thrombosis on immediately postoperative computed tomographic scans, except in 1 patient with a proximal leak, which was managed successfully with angiographic embolization. The mean follow-up time was 12 months. Aortic aneurysm diameter decreased from 2 mm at 6 months (2 patients) to 6 mm at 12 months (6 patients). All axillofemoral bypass grafts are patent. CONCLUSIONS: Placement of an occluding endograft associated with axillofemoral bypass grafting is a good alternative for patients at high risk with complex anatomic features. Longer-term follow-up study is needed to evaluate this endoluminal technique.