Strict Fasting Window May Be Unwarranted Before Cardiac Cath

LONG BEACH, Calif. — Patient well-being was better among individuals allowed more liberal oral intake before entering the catheterization lab, the randomized CALORI trial showed.

Compared to standard fasting after midnight before catheterization, unrestricted oral intake was associated with significant improvements in the distribution of patient satisfaction scores regarding hunger, fatigue, and nausea pre-procedure, according to Brian Mitchell, MD, MPH, a fellow of Virginia Commonwealth University in Richmond.

A composite pre-procedure well-being score — summing hunger and fatigue, each scored on a scale from 0 to 5 — favored the nonfasting group (2.4 vs 6.0 points, P<0.001). On the other hand, pre-procedure anxiety was not helped by liberal oral intake.

Post-procedural patient satisfaction was significantly better in the nonfasting group, Mitchell told the audience here at the Society for Cardiovascular Angiography & Interventions (SCAI).

As for safety, adverse events recorded in the 198-person study amounted to one patient in each arm experiencing periprocedural emesis. There was no aspiration or need for intubation following either fasting (nils per os, or NPO) or nonfasting strategy.

“An ad libitum non-fasting strategy did not increase risk despite a high comorbidity burden, although this study was not powered to detect rare adverse events,” Mitchell concluded. “These findings, together with prior studies, suggest that routine fasting prior to cardiac catheterization should be reconsidered.”

Based on study results, Mitchell said that his group has approached the institution’s anesthesiology department with the intent to shorten the fasting interval for selected patients scheduled for cardiac cath. In the meantime, the official fasting policy remains due to fears of periprocedural aspiration in patients.

Mitchell acknowledged that CALORI was not powered to detect rare events like aspiration. A study would require tens of thousands of patients to prospectively identify such a risk, given aspiration rates of approximately 0.01% in retrospective studies of deep sedation and anesthesia, he said.

Nevertheless, the present report “does push the needle” and the usual fasting window could be moved closer to 2.5 hours, suggested SCAI panelist J. Dawn Abbott, MD, of Rhode Island Hospital in Providence.

“Ironically, the sickest patients are done without fasting,” Abbott added, citing for example people with ST-segment elevation myocardial infarction and cardiovascular shock who “could have come from the restaurant” and already go to the cath lab without fasting in current practice.

Patients randomized to non-fasting in Mitchell’s report had been allowed an unrestricted diet and oral intake of solids and liquids until they were transferred to the cath lab. Time from most recent oral intake to the procedure was 148 minutes. In contrast, for the controls assigned NPO after midnight, time was 970 minutes between last oral intake and the procedure (P<0.001).

“Few studies have prospectively explored this strategy in such a diverse patient population, and with such liberal non-fasting allowances, making it the most comprehensive and generalizable study on this topic to date,” Mitchell said in a SCAI press release. “Given our findings, we hope that providers will limit pre-procedural fasting to those patients at high risk of aspiration or conversion to general anesthesia.”

Panelist Margaret McEntegart, MD, of NewYork-Presbyterian/Columbia University Irving Medical Center in New York City, shared that she is personally also trying to get her institution to change its fasting policy with the expectation of a “huge” boost in patient satisfaction.

“If you cancel a case because someone had a hot dog for lunch,” it means a longer stay and ultimately a huge cost to the hospital with no obvious benefit, said Ian Gilchrist, MD, of Penn State Health Milton S. Hershey Medical Center in Hershey, Pennsylvania, another session discussant.

The single-center CALORI trial enrolled adult inpatients the morning of their scheduled cardiac catheterization, either elective or urgent, in 2023. Key exclusion criteria included BMI over 45 kg/m2, active gastrointestinal illness or nausea, active pregnancy, and hemodynamic instability.

The included patients averaged 61 years, and approximately 65% were men. Those undergoing left heart catheterization represented over 62% of the group, with the rest getting right heart catheterization. Baseline characteristics were comparable between NPO and nonfasting groups.

Medication intake was not affected by assigned treatment. Percutaneous coronary intervention was performed in approximately a quarter of cases.

No significant differences were seen between pre- and post-procedural renal function or blood glucose.

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