Supplemental oxygen controls cellular proliferation and anastomotic intimal hyperplasia at a vascular graft-to-artery anastomosis in the rabbit.

PURPOSE: The purpose of this study was to determine whether the administration of 40% supplemental oxygen (O ( 2) ) will decrease cellular proliferation and intimal hyperplasia (IH) at a prosthetic vascular graft (PVG)-to-artery anastomosis. METHODS: Twenty New Zealand white rabbits underwent placement of a 3-mm polytetrafluoroethylene graft in their infrarenal aorta. Four groups of five rabbits were placed either in a normoxic (21%) environment or in a 40% supplemental O ( 2) environment for 7 or 42 days. Twenty-four hours before the rabbits were humanely killed for aortic graft harvest, BrDU (5-bromo-2'-deoxyuridine) was injected into the rabbits intraperitoneally. Image analysis (Bioquant) morphometrics were used to measure cells with BrDU staining and intimal areas at the distal anastomosis. Cellular proliferation is defined as positively staining BrDU cells divided by all cells in the artery wall. IH is reported as a ratio between the intimal area and the medial area to standardize the varying aortic size and degree of aortic fixation among rabbits. The Student t test was used to compare cellular proliferation and IH between control and O ( 2) -treated rabbits. RESULTS: Cellular proliferation in the intima at 7 days was significantly reduced in the O ( 2) -treated animals (1.7% +/- 1%) versus the control animals (28.6% +/- 3%) ( P =.0001). The cellular proliferation in the intima at 42 days returned to preoperative levels in the O ( 2) -treated group (0.15%) and in the control group (0.11%) ( P = not significant). IH at 7 days was minimal, and no difference between the O ( 2) -treated group (0.017 +/-.006) and the control group (0.009 +/-.03) ( P = not significant) was found. IH was significantly reduced at 42 days in the O ( 2) -treated animals (0.031 +/-.012) when compared with the control animals (0.193 +/-.043) ( P =.006). CONCLUSIONS: Supplemental O ( 2) (40%) significantly reduces cellular proliferation and IH at the distal anastomosis of a PVG-to-artery anastomosis in the rabbit model.

Revascularization and quality of life for patients with limb-threatening ischemia.

Traditional outcomes following revascularization for chronic critical limb ischemia consider limb retention and hemodynamic results. Health-related quality of life is not measured. This study was undertaken to determine if surgery for chronic critical limb ischemia improves health-related quality of life. Forty-six patients undergoing revascularization (anklebrachial index <0.4 for nondiabetics, ankle-brachial index <0.6 for diabetics and rest pain or nonhealing ischemic ulcers) completed pre- and postoperative Short-Form 36 questionnaires, which were used to assess health-related quality of life in patients undergoing arterial reconstruction for chronic critical limb ischemia. Patients reported a mild improvement in functional status postoperatively, and overall low health-related quality of life. Health-related quality of life is slow to show progress following revascularization. Health-related quality of life should become an important outcomes end point.

Transarterial wall oxygen gradients at the deployment site of an intra-arterial stent in the rabbit.

Intimal hyperplasia, common at the deployment site of an intra-arterial stent, may be caused by artery wall hypoxia. The purpose of this study was to determine the effect of an intra-arterial stent on artery wall oxygen concentrations. Transarterial wall oxygen gradients were measured by microelectrode at stent deployment sites in New Zealand White rabbits. Thinned artery walls and decreased oxygen tensions were noted throughout the artery wall immediately following stent deployment with a return toward control values at 28 days. Angioplasty alone had no acute effect on artery wall oxygen concentrations. Larger stent deployment diameters yielded acutely lower artery wall oxygen tensions. Using a linear one-dimensional model for the oxygen profile, we noted that stent deployment resulted in acute changes in oxygen consumption in the inner artery wall that rapidly returned to control values. Changes were noted without differences in blood pressure or arterial blood oxygen concentrations. Oxygen delivery to and consumption within the artery wall are altered by intra-arterial stent deployment. A role for artery wall hypoxia in artery wall pathology at the deployment site of an intra-arterial stent is supported by these findings.