Inhaled albuterol produced a significantly blunted fall in the digital volume pulse inflection point (IP(DVP)) in type II diabetes patients compared to controls (5.9% vs 11.8%, p<0.02).
Case-Control (n=20)
Does the digital volume pulse index of pressure wave reflection (IP(DVP)) detect impaired endothelium-dependent vasodilation in patients with type II diabetes mellitus?
The digital volume pulse index (IP(DVP)) can be used to assess endothelium-dependent vasodilation and demonstrates impaired endothelial function in patients with type II diabetes.
Absolute Event Rate: 5.9% vs 11.8%
p-value: p=<0.02
OBJECTIVES: We sought to determine whether a simple index of pressure wave reflection may be derived from the digital volume pulse (DVP) and used to examine endothelium-dependent vasodilation in patients with type II diabetes mellitus. BACKGROUND: The DVP exhibits a characteristic notch or inflection point that can be expressed as percent maximal DVP amplitude (IP(DVP)). Nitrates lower IP(DVP), possibly by reducing pressure wave reflection. Response of IP(DVP) to endothelium-dependent vasodilators may provide a measure of endothelial function. METHODS: The DVP was recorded by photoplethysmography. Albuterol (salbutamol) and glyceryl trinitrate (GTN) were administered locally by brachial artery infusion or systemically. Aortic pulse wave transit time from the root of the subclavian artery to aortic bifurcation (T(Ao)) was measured by simultaneous Doppler velocimetry. RESULTS: Brachial artery infusion of drugs producing a greater than threefold increase in forearm blood flow within the infused limb was without effect on IP(DVP), whereas systemic administration of albuterol and GTN produced dose-dependent reductions in IP(DVP). The time between the first and second peak of the DVP correlated with T(Ao) (r = 0.75, n = 20, p < 0.0001). The effects of albuterol but not GTN on IP(DVP) were attenuated by N(G)-monomethyl-L-arginine. The IP(DVP) response to albuterol (400 microg by inhalation) was blunted in patients with type II diabetes mellitus as compared with control subjects (fall 5.9 +/- 1.8% vs. 11.8 +/- 1.8%, n = 20, p < 0.02), but that to GTN (500 microg sublingually) was preserved (fall 18.3 +/- 1.2% vs. 18.6 +/- 1.9%, p = 0.88). CONCLUSIONS: The IP(DVP) is influenced by pressure wave reflection. The effects of albuterol on IP(DVP) are mediated in part through the nitric oxide pathway and are impaired in patients with type II diabetes.
Chowienczyk et al. (Wed,) conducted a case-control in Type II diabetes mellitus (n=20). Albuterol and glyceryl trinitrate (GTN) vs. Control subjects was evaluated on Fall in percent maximal DVP amplitude (IP(DVP)) in response to albuterol (p=<0.02). Inhaled albuterol produced a significantly blunted fall in the digital volume pulse inflection point (IP(DVP)) in type II diabetes patients compared to controls (5.9% vs 11.8%, p<0.02).
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