Fasting before coronary angiography could well be unwarranted

04 Jun 2025
Fasting before coronary angiography could well be unwarranted

A new meta-analysis suggests that fasting before elective coronary angiography is not necessarily beneficial in terms of reducing adverse events (AEs) and may even reduce patient satisfaction.

Pooled data from eight randomized controlled trials showed that preprocedural fasting had no notable effect on the incidence of composite AEs including pneumonia, nausea/vomiting, and hypoglycaemia compared with a nonfasting strategy (crude risks, 4.9 percent and 4.5 percent, respectively; odds ratio [OR], 1.08, percent confidence interval [CI], 0.78–1.51), with no evidence of heterogeneity (I2=0). [J Am Heart Assoc 2025;doi:10.1161/JAHA.124.040445]

When individual AEs were assessed, fasting was not associated with a significant reduction in the incidence of pneumonia (crude risks, 0.1 percent and 0.2 percent; OR, 0.48, 95 percent CI, 0.09–2.64; I2=0) and nausea/vomiting (crude risks, 3.7 percent and 3.6 percent; OR, 0.99, 95 percent CI, 0.65–1.53; I2=0) compared with nonfasting.

However, a weak evidence of an effect was observed in favour of nonfasting for hypoglycaemia (crude risks, 2.5 percent and 1.9 percent; OR, 1.34, 95 percent CI, 0.78–2.29; I2=0), hypotension (crude risks, 5.6 percent and 4.3 percent; OR, 1.34, 95 percent CI, 0.80–2.22; I2=51 percent), and hyperglycaemia (crude risks, 6.0 percent vs 4.2 percent; OR, 1.51, 95 percent CI, 0.91–2.50; I2=0).

For patient satisfaction, there was strong evidence favouring a nonfasting strategy (standardized mean difference, 0.62, 95 percent CI, 0.11–1.13). However, results were heterogeneous, potentially due to the different procedures and scales used to measure satisfaction across the studies.

The findings of this meta-analysis “are in line with the trend observed in recent years, that fasting before cardiac catheterization has been abandoned in many centres,” according to the investigators.

The eight trials included in the meta-analysis involved a total of 3,147 patients (mean age 69 years, 72 percent had hypertension, 33 percent had diabetes, 54 percent had hypercholesterolemia), of which 1,579 were in the fasting group and 1,568 were in the nonfasting group. The risk of bias across the trials was low.

Fasting as precaution

In current practice, patients are typically instructed to fast at least 6 hours as a precaution against gastric content aspiration in case of emergent intubation. [Anesthesiology 2017;126:376-393]

“Unfortunately, in many cases, accurately predicting the timing of procedures can be challenging due to emergencies requiring immediate access to the catheterization laboratory. This often results in delays for less urgent cases, leading to prolonged and sometimes repeated fasting. For a patient population that is often frail and older, this situation can be a significant source of inconvenience and dissatisfaction,” the investigators said.

The necessity of fasting before coronary angiography has been increasingly challenged given the extremely low rate of adverse events observed in patients with acute coronary syndromes, especially those with ST‐segment–elevation myocardial infarction, that require urgent coronary angiography independently of their fasting state, they noted. [Heart 2014;100:658-661; Heart Lung Circ 2023;32:S434-S435]

Indeed, in a recent study that included a small cohort of high‐risk patients with non–ST‐segment–elevation myocardial infarction and ST‐segment–elevation myocardial infarction (n=18), there were no cases of aspiration pneumonia documented. [Am J Med 2024;137:666-672]

“Our results question the necessity of current traditional fasting protocols in the context of elective, nonemergent procedures where general anaesthesia is not used, and the rate of complication remains low,” the investigators said.

The low incidence of AEs during cardiac catheterization … supports the adoption of more flexible protocols, with nonfasting protocols having the potential to enhance patient satisfaction without compromising safety, they added.

Then again, the decision regarding fasting should remain individualized, and caution must be taken when considering higher risk procedures or more critically ill patients, where the risk of emergent orotracheal intubation is higher, according to the investigators.