NEW YORK (Reuters Health) – Appropriate use of intravenous narcotics is safe and perhaps even beneficial in patients with acute coronary syndromes, according to Israeli researchers.
In general, professional guidelines support intravenous narcotic use for acute coronary syndrome (ACS). The researchers note, however, that one U.S. registry study (CRUSADE) reported higher hospital mortality in patients with non-ST segment elevation ACS who received IV narcotics, and few data are available regarding the safety of these drugs for ST-segment elevation.
Lead author Dr. Zaza Iakobishvili, from Rabin Medical Center, Petah Tikva, and colleagues used registry data to analyze 30-day outcomes for all cases of ACS treated in Israel during a two-month period in 2008.
Narcotics could improve outcomes “by decreasing the heightened sympathetic tone associated with pain, thus reducing oxygen demand, and hence ongoing ischemia,” Dr. Iakobishvili told Reuters Health by email.
As reported in the February 16th online issue of the American Journal of Cardiology, 261 of 765 patients (34.1%) with ST-segment elevation and 97 of 993 (9.8%) with non-ST-segment elevation ACS received IV narcotics.
Patients with ST-elevation ACS had significantly lower 30-day mortality if they received narcotics (3.1%, vs 6.7% without narcotics, p = 0.04). They also had a trend toward lower rates of in-hospital mortality, cardiogenic shock, and the 30-day combined end-point (death, recurrent infarction, reischemia, stent thrombosis, and stroke).
After propensity score analysis of 249 matched pairs and logistic regression analysis, the difference in 30-day mortality was no longer significant, the authors report, although it still favored the narcotics group.
Patients with non-ST elevation ACS were more likely to be treated with IV narcotics if they had heart failure, the authors said. In this group, rates of in-hospital and 30-day mortality, cardiogenic shock, and the 30-day combined endpoint were not affected by narcotic use. Results were similar after propensity and logistic regression analyses.
The use of evidence-based and guideline-recommended treatments did not differ between patients who did or did not receive IV narcotics.
Asked why the effects of narcotics would differ according to patient presentation, Dr. Iakobishvili said, “ST elevation usually is associated with an occluded artery and a more dramatic presentation, including worse angina. Therefore, morphine is more commonly needed.”
On the other hand, in non-ST segment elevation ACS, patients tend to have less pain and more shortness of breath. “Morphine can exacerbate shortness of breath by reducing the respiratory drive,” Dr. Iakobishvili said.
The investigators note that use of narcotics was almost three-fold greater in the CRUSADE registry than in their own, and that the more limited and selected use likely accounts for differences in outcomes.
Still, they caution, there may have been unmeasured confounding, and they did not have information on the exact timing and cumulative dose of narcotics.
In conclusion, Dr. Iakobishvili said that with prudent use, “narcotics are appropriate for ACS patients with ongoing chest pain, but they should be avoided for patients with severe respiratory diseases who may have an already compromised respiratory drive.”
Am J Cardiol 2010.