Background/Purpose: Gout is an independent risk factor for cardiovascular disease (CVD). Investigators studying the relationship between gout and CVD have focused on acute coronary outcomes, with limited evidence available regarding peripheral arterial function. Using high-resolution ultrasound imaging of the brachial artery, we examined endothelial and smooth muscle arterial function in gout subjects versus healthy controls.

Methods: 34 untreated male gout subjects and 64 healthy control males were included. By enrollment criteria some gout subjects, but no healthy controls, had coronary artery disease (CAD) or diabetes, or were current smokers. Demographics and medical history were recorded. Participants underwent brachial artery flow-mediated dilation (FMD; arterial response to blood flow after transient interruption using a distal blood pressure cuff) and nitroglycerine-mediated dilation (NMD) to assess endothelium-dependent and independent arterial smooth muscle responsiveness, respectively. Dynamic ultrasound images were assessed by two independent observers, with results reported as percentage change in arterial diameter from baseline.

Results: Compared with healthy controls, gout subjects had a higher prevalence of CAD (21% vs 0%, p<0.05), chronic kidney disease (76% vs 0, p<0.05), hypertension (71% vs 22%, p<0.05) and hyperlipidemia (50% vs 18%, p<0.05), but a similar low prevalence of diabetes (6% vs 0%, p=0.12).  29% of gout patients were current smokers (p vs control<0.05).  Gout subjects were slightly older (58.9 vs 53.2 years, p<0.05), and significantly more gout patients were African American (44% vs 8%). Both FMD (2.20±3.12 vs 3.56±2.50, p=0.021) and NMD (16.69±9.01 vs 24.51±7.18, p=0.00002) were significantly reduced in the gout group vs controls. Gout non-smokers, white gout patients, and gout patients lacking specific co-morbidities persisted in having decreased FMD and NMD compared with controls.  Gout patients with versus without specific co-morbidities had similar degrees of impaired FMD and NMD.  Analysis of the gout group showed an inverse Pearson correlation between FMD and CRP (R=-0.42, p=0.017), a trend for inverse Pearson correlation between FMD and serum urate (R=-0.31, p= 0.08); but no correlation between NMD and CRP or serum urate.

Conclusion: Compared with healthy controls, patients with gout have reduced arterial function as measured by FMD and NMD.  While the increased prevalence of comorbidities among gout patients may contribute to diminished arterial function, it appears to be insufficient to explain the endothelial and smooth muscle dysfunction observed.  Hyperuricemia and chronic inflammation may contribute to endothelial dysfunction among gout patients, but do not appear to contribute to smooth muscle dysfunction. Whether appropriate gout therapy may improve FMD and NMD in gout patients remains to be determined.