Heart Failure Drug May Not Ease Symptoms in Some
"I think the public should wait for TOPCAT," Cleland said, referring to the acronym Shah's trial goes by.
For the current study, researchers led by Dr. Burkert Pieske, of the Medical University Graz, in Austria, recruited 422 patients diagnosed with diastolic heart failure. They randomly assigned half to add spironolactone to their current treatment, while the rest received inactive placebo pills.
Over one year, the drug did lower patients' blood pressure and improve their heart function. Based on echocardiograms, there was less thickening and resistance in the left ventricle.
But the patients did not report any improvements in their symptoms or quality of life. Nor did they perform any better on a treadmill walking test.
Cleland said it's not surprising that the patients would not be feeling better despite the objective improvement in heart function. That's been seen with other drugs, he noted.
Pieske said that the reasons are not fully clear. It's possible that the drug dose was not high enough, he said. Or the changes in heart function that his team saw may just not translate into benefits such as better walking ability.
On top of that, the patients in this study were actually fairly healthy, Shah and Cleland pointed out. So they may not have been sick enough to expect symptoms or walking ability to get noticeably better.
Shah and Cleland both suspect that many study patients may have had diastolic "dysfunction" in their hearts -- but were not sick enough to really have diastolic heart failure.
"I think that may underlie the findings (on symptoms)," Shah said.
For now, Pieske said doctors could still consider spironolactone for diastolic heart failure patients who need better blood pressure control.
The usual treatments for the condition include lowering blood pressure with drugs such as diuretics and ACE inhibitors, and slowing patients' heart rate with beta-blockers or other medications.
"Most people with diastolic heart failure are hypertensive, and getting blood pressure under good control is very important," Cleland said.
All agreed that better treatments are needed. "There is a real need to find therapies that improve outcomes for people with this form of heart failure," Shah said.
For spironolactone, Shah said more study is needed on whether the drug affects patients' potassium levels too much, which can cause an abnormal heart rhythm. In this study, patients on the drug had a "mild" increase in potassium, on average -- but they didn't have a higher risk of serious increases, and there were no hospitalizations for it.
The study was funded by government grants, but some researchers on the work have financial ties to Aldactone maker Pfizer, Inc.
Learn more about heart failure from the Heart Failure Society of America.