When scheduling a coronary angiography, patients are usually instructed to fast for at least 8 hours (no oral intake after dinner). However, this strategy can lead to negative effects such as discomfort, irritability, dehydration, and even hypoglycemia in some cases. Previous studies have not shown significant differences in gastric complications between patients fasting only 2 hours before the procedure and those fasting for more than 6 hours, with a 0.02% risk of aspiration for subjects undergoing elective procedures and 0.01% for those undergoing emergency procedures.
Several associations, including the American Society of Anesthesiology, recommend fasting for at least 2 hours for liquids and 6 hours for solids before a procedure. A retrospective study involving a considerable number of patients (n=1916) over three years of enrollment showed no patients requiring emergency intubation or developing aspiration pneumonia after the procedure.
Given the scarce data prior to an invasive coronary study, Woods et al. conducted this work with the aim of assessing the need for fasting for conscious sedation before elective coronary procedures.
The study was prospective, randomized, and conducted at a single center in the United States. The primary objective was to compare the safety of a healthy, slightly acidic diet (low-fat, low-cholesterol, and low-sodium foods) before coronary angiography versus following the standard fasting guidelines. The secondary objective was to evaluate patient satisfaction and comfort.
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The study included patients from the cardiac critical care unit, scheduled for cardiac catheterization with conscious sedation and analgesia. Patients with gastric emptying disorders such as chronic nausea, significant hiatal hernia, and enteral feeding, and subjects requiring emergency catheterization were excluded.
The study sample included 197 patients (100 with a healthy diet until the time of catheterization and 97 who fasted for at least 6 hours for solids), with an average age of 62.7 years and male predominance (62.4%). Only diagnostic studies were performed in most cases (57.4%), with angina (70.6%), SCASEST (13.2%), or unstable angina (6.1%) being the main reasons for the invasive study.
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The satisfaction score reported by patients was significantly higher in the healthy diet group (1.3 vs 3.1; p<0.001). Additionally, those subjects experienced lower thirst and hunger levels both before and after catheterization (thirst: 29.2% vs 48.7%, p<0.001; hunger: 22.6% vs 64.7%; p<0.001). No patient experienced aspiration pneumonia, intubation, or hypoglycemia.
Conclusions
The results of this study indicate that in a selected population (without emergency catheterization), a healthy diet before the intervention—without the need for prolonged fasting—is safe. This approach represents an advancement in proper preparation and patient satisfaction, both regarding sedation and the elective coronary procedure.
Dr. Omar Tupayachi.
Member of the Editorial Board of SOLACI.org.
Original Title: Fasting Versus a Heart-Healthy Diet Before Cardiac Catheterization: A Randomized Controlled Trial.
Reference: Carri Woods, Michelle Wood, Angela Boylan, Mindy E. Flanagan, Jan Powers; Fasting Versus a Heart-Healthy Diet Before Cardiac Catheterization: A Randomized Controlled Trial. Am J Crit Care 1 January 2024; 33 (1): 29–33. doi: https://doi.org/10.4037/ajcc2024115.
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