Herbal mainstay hawthorn can benefit in heart failure, says pooled analysis

January 23, 2008

Exeter and Plymouth, UK - Hawthorn extract, a herbal medicinal taken widely for heart health, can improve exercise performance in chronic heart failure without an important risk of side effects, concludes a review of a limited number of randomized, placebo-controlled trials[1].

"The best evidence that is available suggests that hawthorn has significant benefits, compared with placebo, as an adjunctive treatment for patients with chronic heart failure," according to the authors, led by Dr Max H Pittler (Peninsula Medical School, Universities of Exeter and Plymouth, UK). "Reported adverse events were infrequent, mild, and transient," they write in the first 2008 issue of the Cochrane Database of Systematic Reviews, published online January 23.

Crataegus monogyna

Modern extracts of hawthorn, a genus of shrub plants found throughout much of the world, typically derive from the leaves and flowers of a few specific species, such as Crataegus laevigata and C monogyna. All of the reviewed trials used either WS1442 or LI132, commercial preparations with consistent concentrations of the active oligomeric procyanidins; dosages ranged widely, however.

There are abundant data attesting to hawthorn's low risk of side effects, Pittler et al observe. And hawthorn extract was given on top of standard heart-failure medications in most of the studies the group reviewed. But given theoretical concerns about hawthorn interactions with conventional drugs and laboratory evidence for possible adverse effects, the authors recommend against the herbal's use without physician supervision. "We believe that hawthorn extracts are not ideal candidates for the over-the-counter market."

The group screened published and unpublished studies of hawthorn extract for heart failure to identify 14 meeting their inclusion criteria, which included randomized, placebo-controlled design, classification of all patients by NYHA class, appropriate end points, and data reporting that allowed intention-to-treat analysis. A total of 1110 patients in the trials were followed for up to 26 weeks.

Taken together, the studies suggested that the herbal treatment, given with standard heart-failure medications, can increase exercise performance and cardiac oxygen consumption and may improve heart-failure symptoms such as dyspnea and fatigue. Rarely did the studies report mortality or rates of cardiac events.

Significant effects of hawthorn extract vs placebo in chronic heart failure, pooled analyses of randomized, placebo-controlled trials

End point Studies, n Patients, n WMD (95% CI) p
Maximal workload 5 380 +5.35 (0.71 to 10.00) W 0.02
Rate-pressure product 5 264 -19.22 (-30.46 to -7.98) mm Hg/min 0.0008
Symptom score 3 239 -5.47 (-8.68 to -2.26) 0.0008
Exercise tolerance 2 98 +122.76 (32.74 to 212.78) W x min 0.008
WMD=weighted mean difference, hawthorn extract vs placebo

Reported adverse events included "nausea, dizziness, and cardiac and gastrointestinal complaints."

Not included in the review was the Survival and Prognosis: Investigation of Crataegus Extract WS1442 in CHF (SPICE) trial, which was ongoing as Pittler et al were screening relevant trials. As reported by heart wire when the study was later presented at the American College of Cardiology 2007 Scientific Sessions, adding the herbal to ACE inhibitors, beta blockers, and other components of contemporary therapy failed to alter a composite primary end point that included sudden cardiac death, death due to progressive heart failure, fatal or nonfatal MI, and HF hospitalization at 24 months. The trial did support hawthorn extract's good safety record, however.

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