DEFER: PCI unnecessary for intermediate stenosis with no inducible ischemia

Shelley Wood

September 26, 2005

Stockholm, Sweden - Patients with intermediate coronary stenoses but no inducible ischemia do not benefit from stenting and suffer similar rates of adverse events over five years of follow-up as patients who do not undergo PCI, results from the DEFER study show. The findings should serve as a reminder to physicians that even in the era of drug-eluting stents (DESs), preventive stenting or "plaque sealing" will not necessarily prevent future AMI; inducible myocardial ischemia remains the most important prognostic factor in patients with stable chest pain and a known coronary stenosis, researchers say.

Dr Nico Pijls (Catharina Hospital, Eindoven, the Netherlands) presented the five-year results from DEFER earlier this month at the European Society of Cardiology 2005 Congress.

Pijls summarized the results in an interview with heartwire : "If a lesion is limiting blood flow you should treat it, and even then, with the best possible treatment, you know that the patient will likely have a worse outcome than a patient with a nonsignificant stenosis. And if the stenosis is nonsignificant, the outcome is quite favorable anyway and won't improve by stenting, so you can save the money and all the risk of stenting and possibly have an even better prognosis with just medical treatment."

Pijls and colleagues measured fractional flow reserve (FFR) in 325 patients scheduled to undergo PCI. If the FFR was >0.75, indicating a nonischemic stenosis, patients were randomized to either PCI (n=90) or deferral of PCI (n=91). Patients with an FFR <0.75, indicating ischemic stenosis, underwent PCI and were included in the study as the reference group.

At five years of follow-up, the authors saw no significant differences in angiographic severity between the PCI and deferred-PCI group. Likewise, cardiac and noncardiac deaths, MI, CABG, and repeat PCI rates were equivalent between the two groups. Examined by year, stented patients had a 1.5% risk of dying or having an MI, whereas patients treated conservatively, with statins and aspirin, had only a 0.6% risk, Pijls told heartwire .

DEFER: Five-year outcomes

Outcomes FFR >0.75, PCI deferred FFR >0.75, PCI performed FFR <0.75, reference group
Cardiac death 2 2 7
AMI 0 5 13
CABG 1 4 11
(Re)-PCI 15 13 22
Noncardiac deaths 3 3 3
Total 21 27 56
"Five-year outcomes after deferral of PCI are excellent," Pijls concluded. "The risk of such functionally nonsignificant stenosis to cause death or AMI is only <1% per year and not decreased by stenting."

To heartwire , Pijls pointed out that the AHA guidelines recommend demonstration of myocardial ischemia, typically by exercise stress test or perfusion scanning, before PCI is performed. "The problem is nowadays we are living in a very hurried, sped-up society, and when certain patients present with chest pain, instead of waiting one or two weeks before such tests can be performed, patients are brought immediately to the catheterization laboratory."

A strategy DEFERred

Commenting on the study for heartwire , Dr Michel Romanens (Kardiolab, Olten, Switzerland) agreed that DEFER proves that the strategy of first screening for inducible ischemia is still sound.

"This is the old-fashioned approach, where you do myocardial-perfusion studies using SPECT or stress echo, to first try to find ischemia and ascertain whether the symptoms of the patient are caused by myocardial malperfusion during exercise, and then do some kind of intervention on the patient. Now, because the issues of restenosis have largely disappeared with DESs, it appears so easy to just perform interventions."

But, he warns, drug-eluting stents are not entirely without risk. "DESs can cause late thrombosis, and I think the 'dark number' of unrecognized sudden deaths due to DES late thrombosis is not known; I think it's about 1%, and this is not a negligible number."

He continued, "The DEFER study has shown clearly that when you don't have ischemia, you have a low-risk patient, and frequently when you intervene in patients with no ischemia, you don't improve the functional outcome or symptoms. That's the key message of the DEFER study, that if you don't have ischemia, you shouldn't touch these patients."

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