Key result
Patients with idiopathic dilated cardiomyopathy exhibited a significantly blunted increase in plasma adenosine levels following dipyridamole infusion compared to normal controls (322 vs 732 nM L-1; P<0.001).
Why the study?
Does dipyridamole stress reveal a blunted increase in plasma adenosine levels in patients with idiopathic dilated cardiomyopathy compared to normal controls?
Case-Control (n=34)
Does dipyridamole stress reveal a blunted increase in plasma adenosine levels in patients with idiopathic dilated cardiomyopathy compared to normal controls?
Absolute Event Rate: 322% vs 732%
p-value: p=< 0.001
Patients with idiopathic dilated cardiomyopathy exhibit abnormally high baseline adenosine levels and a blunted increase following dipyridamole stress, suggesting chronic activation of the adenosinergic system.
Blunted adenosine response may indicate chronic adenosinergic activation in IDC; hypothesis-generating and requires prospective validation before clinical consideration.
BACKGROUND: Heart failure is characterized by chronically increased adenosine levels, which are thought to express a protective anti-heart failure activation of the adenosinergic system. The aim of the study was to assess whether the activation of adenosinergic system in idiopathic dilated cardiomyopathy (IDC) can be mirrored by a blunted increase in plasma adenosine concentration following dipyridamole stress, which accumulates endogenous adenosine. METHODS: Two groups were studied: IDC patients (n = 19, seven women, mean age 60 +/- 12 years) with angiographically confirmed normal coronary arteries and left ventricular ejection fraction <35%; and normal controls (n = 15, six women, mean age 68 +/- 5 years). Plasma adenosine was assessed by high-performance liquid chromatography methods in blood samples from peripheral vein at baseline and 12 min after dipyridamole infusion (0.84 mg kg-1 in 10 min). RESULTS: At baseline, IDC patients showed higher plasma adenosine levels than controls (276 +/- 27 nM L-1 vs. 208 +/- 48 nM L-1, P < 0.001). Following dipyridamole, IDC patients showed lower plasma adenosine levels than controls (322 +/- 56 nM L-1 vs. 732 +/- 250 nM L-1, P < 0.001). The dipyridamole-induced percentage increase in plasma adenosine over baseline was 17% in IDC and 251% in controls (P < 0.001). By individual patient analysis, 18 IDC patients exceeded (over the upper limit) the 95% confidence limits for normal plasma adenosine levels at baseline, and all 19 exceeded (below the lower limit) the 95% confidence limits for postdipyridamole plasma adenosine levels found in normal subjects. CONCLUSION: Patients with IDC have abnormally high baseline adenosine levels and--even more strikingly--blunted plasma adenosine increase following dipyridamole infusion. This is consistent with a chronic activation of the adenosinergic system present in IDC, which can be measured noninvasively in the clinical theatre.
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Laghi‐Pasini et al. (2003) conducted a case-control in Idiopathic dilated cardiomyopathy (n=34). Idiopathic dilated cardiomyopathy vs. Normal controls was evaluated on Plasma adenosine levels 12 min after dipyridamole infusion (nM L-1) (p=< 0.001). Patients with idiopathic dilated cardiomyopathy exhibited a significantly blunted increase in plasma adenosine levels following dipyridamole infusion compared to normal controls (322 vs 732 nM L-1; P<0.001).
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