Resting heart rate pattern during follow-up and mortality in hypertensive patients.

There is a linear relationship between resting heart rate (HR) and mortality in normotensive and untreated hypertensive individuals. However, it is not clear whether HR is a marker of increased risk in hypertensive patients on treatment. We investigated the relationship between HR and mortality in patients with hypertension. We analyzed baseline HR, final HR, and HR change during follow-up in patients attending the Glasgow Blood Pressure Clinic. Using a threshold of 80 bpm, we classified patients into those who had a consistently high (high-high) or low (low-low) HR or patients whose HR increased (low-high) or decreased (high-low) over time. Survival analysis was carried out using Cox proportional hazards models adjusted for age, sex, body mass index, smoking, rate-limiting therapy, systolic blood pressure, and serum cholesterol. For each beat of HR change there was a 1% change in mortality risk. The highest risk of an all-cause event was associated with patients who had increased their HR by >or=5 bpm at the end of follow-up (1.51 [95% CI: 1.03 to 2.20]; P=0.035). Compared with low-low patients, high-high patients had a 78% increase in the risk of all-cause mortality (HR: 1.78 [95% CI: 1.31 to 2.41]; P<0.001). Cardiovascular mortality showed a similar pattern of results. Rate-limiting therapy did not have an independent effect on outcomes in this analysis. Change in HR achieved during follow-up of hypertensive patients is a better predictor of risk than baseline or final HR. After correction for rate-limiting therapy, HR remained a significant independent risk factor.

The effect of allopurinol on the cerebral vasculature of patients with subcortical stroke; a randomized trial.

AIMS: New preventative strategies for stroke are required. One promising strategy is uric acid reduction and xanthine oxidase inhibition with allopurinol. We sought to investigate whether allopurinol improves cerebrovascular reactivity (CVR) following subcortical stroke. METHODS: We performed a randomized, double-blind, controlled study to investigate the effect of a 3-month course of 300 mg allopurinol once daily vs. placebo on CVR in individuals with recent (within 6 months) subcortical stroke. Participants were randomized on a 1:1 basis. CVR was defined as the percentage change in middle cerebral artery flow velocity following an intravenous injection of 15 mg kg(-1) of acetazolamide. Our primary end-point was the CVR difference between baseline and 3 months. Secondary end-points included measures of peripheral vascular reactivity and blood markers of inflammation and endothelial activation. RESULTS: We enrolled 50 participants; 45 completed the protocol. Baseline serum urate was 0.35 mmol l(-1) (SD 0.1) and 0.34 mmol l(-1) (SD 0.1) in the allopurinol and placebo groups, respectively. There were no serious adverse events related to treatment. CVR did not change following treatment with allopurinol [median CVR change 0.89% after allopurinol (n = 20) and -0.68% after placebo (n = 25); 95% confidence interval for estimated difference in medians -13.4, 25.5, P = 0.64]. Urate was significantly lowered by allopurinol but no change in other secondary end-points was seen. CONCLUSION: Xanthine oxidase inhibition with allopurinol has previously been shown to improve cerebrovascular function, but no benefit was seen in this study. It may therefore be that previous encouraging findings will not translate into important clinical benefits.

Allopurinol and nitric oxide activity in the cerebral circulation of those with diabetes: a randomized trial.

OBJECTIVE: Type 2 diabetes increases risk of stroke, perhaps because of impaired cerebrovascular basal nitric oxide (NO) activity. We investigated whether this activity is improved by a 2-week course of the xanthine oxidase inhibitor allopurinol. RESEARCH DESIGN AND METHODS: We performed a randomized, double-blind, placebo-controlled crossover study. We measured the response to infusion of NG-monomethyl-L-arginine (l-NMMA) in males with type 2 diabetes before and after allopurinol or placebo. The primary end point was the change in internal carotid artery flow following L-NMMA infusion, expressed as the area under the flow-per-time curve. RESULTS: We enrolled 14 participants. Allopurinol improved responses to L-NMMA when compared with responses associated with placebo (P = 0.032; median reduction in internal carotid artery flow following L-NMMA of 3,144 ml [95% CI 375-7,143]). CONCLUSIONS: Xanthine oxidase inhibition with allopurinol appears to improve cerebral NO bioavailability, as evidenced by a greater response to infusion of L-NMMA.

Allopurinol use yields potentially beneficial effects on inflammatory indices in those with recent ischemic stroke: a randomized, double-blind, placebo-controlled trial.

BACKGROUND AND PURPOSE: Elevated serum uric acid level is associated with poor outcome and increased risk of recurrent events after stroke. The xanthine oxidase inhibitor allopurinol lowers uric acid but also attenuates expression of inflammatory adhesion molecules in murine models, reduces oxidative stress in the vasculature, and improves endothelial function. We sought to investigate whether allopurinol alters expression of inflammatory markers after acute ischemic stroke. METHODS: We performed a randomized, double-blind, placebo-controlled trial to investigate the safety, tolerability, and effect of 6 weeks' treatment with high- (300 mg once a day) or low- (100 mg once a day) dose allopurinol on levels of uric acid and circulating inflammatory markers after ischemic stroke. RESULTS: We enrolled 50 patients with acute ischemic stroke (17, 17, and 16 in the high, low, and placebo groups, respectively). Mean (+/-SD) age was 70 (+/-13) years. Groups had similar characteristics at baseline. There were no serious adverse events. Uric acid levels were significantly reduced at both 7 days and 6 weeks in the high-dose group (by 0.14 mmol/L at 6 weeks, P=0.002). Intercellular adhesion molecule-1 concentration (ng/mL) rose by 51.2 in the placebo group, rose slightly (by 10.6) in the low-dose allopurinol group, but fell in the high-dose group (by 2.6; difference between groups P=0.012, Kruskal-Wallis test). CONCLUSIONS: Allopurinol treatment is well tolerated and attenuates the rise in intercellular adhesion molecule-1 levels seen after stroke. Uric acid levels were lowered with high doses. These findings support further evaluation of allopurinol as a preventive measure after stroke.