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“There was a physiologic response to spironolactone that paralleled an apparent outcome response,” Dr. Hochman concluded.
As for the discordant Eastern European data, she observed that confirming the diagnosis of HFpEF may be difficult: “Dyspnea, orthopnea, fatigue, lower extremity edema – all of these may be caused by other conditions. So it’s very complicated.”
In contrast to heart failure with reduced ejection fraction, which has seen enormous treatment advances in recent years, not much progress has been made in HFpEF. For that to occur, Dr. Hochman said, it will be essential to come up with refined, objective diagnostic criteria for use in clinical trials. Perhaps echocardiographic findings or elevated natriuretic peptide levels will fill that role, she added.
However, Dr. Pfeffer said that, much to his disappointment, he and other investigators have not seen a consistent correlation between higher baseline brain natriuretic peptide levels and greater clinical response to mineralocorticoid receptor antagonist therapy.
Asked what sort of oversight he and the other TOPCAT leaders had over the Russian and Georgian study sites, Dr. Pfeffer replied that the National Institutes of Health–sponsored study was underfunded for such monitoring.
“As one of the leaders of the trial, there are a lot of things that I would have wished to have done differently,” he said. “I have to stand here and say the amount that you get is inadequate to do what happens in industry-sponsored trials if there’s a perceived problem.”
Both Dr. Pfeffer and Dr. Hochman emphasized the critical importance of careful monitoring of serum potassium and creatinine when prescribing spironolactone in patients with HFpEF. But with regular monitoring, Dr. Pfeffer observed, the risk of major elevations is reassuringly low. For example, with monitoring of serum creatinine at every clinic visit and dose change as per TOPCAT protocol, the incidence of a level of 3.0 mg/dL or more was 10% with spironolactone and not significantly different at 9% with placebo in the Americas.
Dr. Pfeffer reported having received consultant fees from 20 pharmaceutical or medical device companies.