NOMI: Nitric oxide did not reduce infarct size in STEMI

BARCELONA, Spain — Inhaled nitric oxide during PCI for STEMI failed to reduce infarct size in the total population but showed some interaction with nitroglycerin, according to findings from the NOMI trial presented here.

Stefan P. Janssens, MD, PhD, said that inhaling nitric oxide has demonstrated the capacity to reduce infarct size and improve left ventricular function and structural recovery after PCI for STEMI.

Eligible participants in this phase 2, multicenter, randomized controlled trial presented within 2 to 12 hours of first STEMI and had no HF or abnormal oxygen levels. Pre-specified subgroup analyses were based on TIMI flow grade; whether the culprit lesion was in the left anterior descending artery; time to symptom onset; troponin levels at admission; use of systemic nitroglycerin; and use of glycoprotein IIb/IIIa antagonists.

Of the 248 patients enrolled in the study, 122 received placebo and 126 received inhaled nitric oxide at 80 ppm. This treatment was given for up to 4 hours after reperfusion therapy began.

Infarct size — expressed as fraction of LV mass — was not different between the two groups at 48 to 72 hours, according to the results. However, nitric oxide demonstrated an interaction in patients receiving nitroglycerin (P=.0139), but only in patients who were nitroglycerin-naive.

The ratio of infarct size to LV mass was 19.4% in the control group and 18% in the nitric oxide group (P=.44).

“We did not detect a significant reduction in infarct size in the overall population,” Janssen said.

In patients receiving nitroglycerin, the rate was 15.1% for controls and 19.3% for the study drug group (P=.059), while the rates were 22.4% in controls and 17% for the study drug group among patients not receiving nitroglycerin (P=.044).

“Importantly, and quite remarkably, when we looked at patients that were not given any nitroglycerin — which was 60% of our population — there was a significant reduction in the primary endpoint,” he said. “This was not the case in patients who were given systemic nitroglycerin therapy. This was quite a surprise.”

Secondary endpoints included infarct size as measured against the risk area, myocardial salvage index and LV remodeling. For the area at risk outcome, Janssen said that the results favored the inhalation of nitric oxide with a trend toward increased myocardial salvage. “When we looked at remodeling parameters and global functioning by MRI at index hospitalization, there was a trend in favor of the inhaled [nitric oxide] group,” he said, noting a P value of .10. “Remarkably, [the trend] was more accentuated after 4 months.”

A composite endpoint of death, recurrent ischemia, stroke and hospitalization was calculated at 4 months. This rate was 20.4% for controls and 13% for those receiving nitric oxide (P=.1022). Mortality was 6.3% in the control arm and 4.1% among patients receiving nitric oxide.

“In timely reperfused STEMI, inhalation of nitric oxide on top of standard treatment was safe but did not reduce infarct size expressed as a percent of LV mass in the total population,” Janssen said. “In a pre-specified subgroup analysis, we found statistically significant heterogeneity of the inhaled nitric oxide effect in relation to periprocedural nitroglycerin use.”

Janssen added that the study drug showed a trend toward greater myocardial salvage index and enhanced functional recovery that increased over time.– by Rob Volansky

For more information:

Janssens SP. Hot Line IV: Myocardial Infarction. Presented at: the European Society of Cardiology Congress; Aug. 30-Sept. 3, 2014; Barcelona, Spain.

Disclosure: Janssens reports no relevant financial disclosures.