Determinants of Systemic Vascular Function in Patients with Stable Chronic Obstructive Pulmonary Disease

Abstract

SO, et al. Circulation 2009;119:123-30. Conclusion: Female gender and black race are risk factors for adverse events after vein bypass surgery for limb salvage.Summary: This article represents another of the many interesting post hoc analyses derived from the PREVENT III, a multicenter clinical trial of patients undergoing vein bypass for critical limb ischemia (J Vasc Surg 2006;43:742-51). The PREVENT III database represents the largest prospective cohort of patients who underwent surgical treatment for critical limb ischemia. The database includes 1404 lower extremity vein graft operations performed for critical limb ischemia at 83 North American centers. The patients had intensive ultrasound surveillance of the bypass graft and clinical follow-up for 1 year.This particular analysis was designed to examine the interactions of race and gender as they affect graft patency, limb salvage, and mortality. Proportional hazards and propensity scoring was used to examine relationships of patient demographics to relevant clinical end points. These included perioperative events and 1-year outcomes of graft patency, limb salvage, and patient survival. Propensity score models adjusting for covariants that included institution, comorbidities, technical factors, and adjunctive medications were used to examine associations between race, gender, and outcomes.The PREVENT III trial had 249 black patients (131 men and 118 women). Black men were at increased risk for early (30-day) graft failure (hazard ratio [HR], 2.832; 95% confidence interval [CI], 1.393-5.759; P ϭ .0004). This held true even when analysis was restricted to exclude high-risk venous conduits. Black patients also had reduced secondary patency (HR, 1.49; 95% CI, 1.08-2.06; P ϭ .016) and reduced limb salvage (HR, 2.02; 95% CI, 1.27-3.20; P ϭ .003) at 1 year. Black women were the most disadvantaged, with an increased risk of graft thrombosis (HR, 2.02 for secondary patency; 95% CI, 1.27-3.20; P ϭ .003) and an increased risk for major amputation (HR, 2.38; 95% CI, 1.18-4.83; P ϭ .016) at 1 year. Perioperative mortality and 1-year mortality, however, were similar across race and gender groups.Comment: It has been previously suggested that African Americans and women have poorer results with vascular surgery. The findings in this study are therefore not all that surprising. The authors suggest the data raise the possibility of an altered response to vein bypass surgery in there subgroups. It is certainly not obvious what this biologic response would be. Nevertheless, the clinical implication is that African American women undergoing vein graft bypass surgery are a particularly high-risk group that may benefit from very aggressive postoperative surveillance and medical management.

Airflow Limitation and Endothelial Dysfunction. Unrelated and Independent Predictors of Atherosclerosis

“…Specifically, a study that used the gold standard method to assess endothelial function (invasive measurement of forearm vasoreactivity to intraarterial infusion of vasodilators) did not identify an association between airflow limitation and endothelial function (30). In contrast, others have reported statistically significant associations between airflow limitation and endothelial function, although with large differences in effect size (6)(7)(8)(9)(10)(11). For example, there was a greater than 10-fold difference in the magnitude of change in endothelial function per unit change in FEV 1 between two studies (b = 0.22 vs. 0.019; both P , 0.05) (6,10).…”

“…Prior studies that have investigated the relationship between airflow limitation and endothelial function, however, have produced inconsistent results (6)(7)(8)(9)(10)(11)30). Specifically, a study that used the gold standard method to assess endothelial function (invasive measurement of forearm vasoreactivity to intraarterial infusion of vasodilators) did not identify an association between airflow limitation and endothelial function (30).…”

“…Some studies excluded women (8); current smokers (9,11); those treated with statins or antihypertensive medication (6,10); and those with a history of coronary, cerebrovascular, or peripheral artery disease (30) or heart failure (8). In one study only 13% of eligible participants met inclusion criteria (6).…”

“…function that then leads to atherosclerosis) ( Figure 1A) (5,6). Prior studies have examined the relationship between expiratory airflow and endothelial dysfunction but have produced inconsistent results (6)(7)(8)(9)(10)(11).…”

“…Prior studies have examined the relationship between expiratory airflow and endothelial dysfunction but have produced inconsistent results (6)(7)(8)(9)(10)(11). Because these studies did not assess atherosclerosis per se, it remains unknown if endothelial dysfunction mediates the association between FEV 1 and atherosclerosis.…”