Feb 6 2013
By Eleanor McDermid, Senior medwireNews Reporter
Six months of treatment with the angiotensin-converting enzyme (ACE) inhibitor ramipril produces notable improvements in the walking ability of patients with peripheral artery disease (PAD) and intermittent claudication, shows a large randomized trial.
As a result, the patients reported significant improvements in their quality of life, say lead researcher Anna Ahimastos (Baker IDI Heart and Diabetes Institute, Melbourne, Australia) and team in JAMA.
In an accompanying editorial, Mary McGrae McDermott (Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA) notes that patients with PAD respond well to supervised treadmill training, but that such interventions are not usually covered under health insurance.
Thus, identifying drugs that will produce similar effects "is an important public health challenge," she says, adding that, in this study, ramipril produced a substantially greater improvement than has been observed with the only two medications approved in the USA for the treatment of intermittent claudication, pentoxifylline and cilostazol.
After 6 months of treatment, the 106 patients taking placebo had a 14-second improvement in pain-free walking time on a treadmill, from an average of 142 to 156 seconds. But the 106 patients taking ramipril 10 mg/day had an 88-second improvement, from an average of 140 to 229 seconds. The between-group difference of 75 seconds was statistically significant.
Likewise, the patients' maximum walking time on the treadmill increased 255 seconds more in the ramipril group than the placebo group, with respective increases of 23 and 277 seconds.
The benefits seen in the treadmill test extended to patients' quality of life, with those taking ramipril recording a significant 6.3-point improvement on the Physical Component Summary of the Short Form-36, compared with a nonsignificant 0.2-point improvement among those taking placebo.
"Importantly, these associations were additional to those achieved with standard clinical management by a general practitioner or vascular specialist," say Ahimastos et al.
Patients taking ramipril also had significant improvements in several secondary outcomes, including ankle-brachial index and the Walking Impairment Questionnaire - the latter again indicating that the benefits seen on the treadmill extended to the patients' everyday lives.
McDermott cautions that the findings may not be achievable with different ACE inhibitors, or applicable to more diverse groups of patients. In particular, the trial excluded patients with blood pressure above 160/110 mmHg because of ethical concerns.
However, she says that the magnitude of improvement shown by Ahimastos et al is "particularly notable," given the limited treatment options for intermittent claudication.
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