Comparison of 2 Beta Blocker Drugs on Peripheral Arterial Disease in Patients With High Blood Pressure

Peripheral arterial disease (PAD) affects up to an estimated 16-29% of men and women over age 50, and is associated with increased cardiovascular morbidity and mortality. Beta-blockers have been shown to reduce the risk of myocardial infarction and death in patients with coronary artery disease (CAD) and are indicated for the treatment of hypertension in patients with PAD. However, there is a theoretical risk that antihypertensive therapy may decrease limb perfusion pressure and therefore exacerbate symptoms of claudication or limb ischemia. Patients with CAD and concomitant PAD are less likely to be prescribed beta-blockers, even though most patients are able to tolerate antihypertensive therapy without worsening of symptoms. The third generation beta-blocker, nebivolol, has vasodilating properties in addition to beta-adrenergic blockade. This vasodilatory effect is mediated through the L-arginine-nitric oxide-dependent pathway. Nitric oxide is a critical modulator of vascular disease with effects that lead to vasodilatation, endothelial regeneration, inhibition of leukocyte chemotaxis and inhibition of platelet adhesion. This combination of beta-blockade and nitric oxide-dependent vasodilation may enhance effectiveness and tolerability of nebivolol versus other beta-blockers in patients with hypertension, CAD or high-risk state, and PAD. This study will be a pilot comparative effectiveness study to examine the effect of nebivolol versus metoprolol succinate in patients with lower-extremity PAD and at least moderate risk for CAD on PAD symptoms as measured by both functional and quality of life measures.