Starvation before cardiac catheterization called optional

American researchers conducted randomized trials and concluded that patients before routine cardiac catheterization do not need to fast before the intervention, as required by current rules. A publication about this appeared in the American Journal of Critical Care.

Cardiac catheterization is widely used to assess blood flow, pressure, blood gas composition, valve and electrical function, and the anatomic condition of the heart chambers and vessels. According to the existing rules, before routine catheterization, patients are required to abstain from solid food either six hours before the procedure (e.g., in the recommendations of American anesthesiologists) or from the previous evening (e.g., in the Russian recommendations), although in practice the complication-prone fasting often lasts even longer, and the subsequent procedure is often canceled for various reasons. However, in a retrospective study of emergency percutaneous coronary interventions, it was shown that early abstinence from food was not associated with a significant risk of complications.

To determine optimal nutritional recommendations before routine cardiac catheterization, local health system staff with Parkview Health Heart Institute in Indiana, led by Jan Powers, conducted a randomized controlled trial involving 197 adult inpatients who were referred for the procedure under anesthesia and conscious sedation. People with gastric emptying disorders (e.g., chronic nausea and vomiting) or large diaphragmatic hernias, on parenteral nutrition, or undergoing emergency intervention were not included.

One hundred participants were prescribed a cardiac healthy diet with restriction of total fat, cholesterol, sodium, and acidity foods that they could consume at any time before cardiac catheterization. The others were instructed not to consume food starting midnight before the day of the intervention, and were allowed only small amounts of water and oral medications. Before and after sedation, patients were checked for objective symptoms and subjective sensations, possible complications were recorded, and blood glucose levels were analyzed and then monitored throughout their hospital stay. There were no significant demographic differences between the groups. Statistical comparison of continuous measurements was performed using t-tests; for discrete measurements, the χ2 test was used.

It was found that patients who were allowed to eat expressed significantly greater satisfaction with their meals and experienced significantly fewer problems with hunger and thirst before and after catheterization. At the same time, the degree of fatigue, blood glucose level, gastrointestinal complaints and loading dose of antiaggregants in the main and control groups were not statistically significantly different. Complications in the form of pneumonia, aspiration of gastric contents or need for intubation were not observed in any participant.

The authors of the paper noted that while they were processing the data, the European Heart Journal published a report on a similar study conducted by the Guthrie Health System in Pennsylvania. It also confirmed the safety of nutrition before cardiac catheterization, but did not take into account the level of subjective satisfaction of participants. The sum of these data provides evidence that patients can be allowed to eat before such a procedure, and appropriate clinical guidelines need to be revised.

Existing attitudes to abstain from food before a variety of medical interventions (nil per os approach) have been questioned before. For example, in public obstetric facilities in most countries, women in labor are not allowed to eat or drink. However, systematic reviews of multiple controlled trials have argued against this practice, and private clinics often advise women to stock up on light food before an uncomplicated planned delivery.