Daytime PCI Outcomes Not Compromised By Operators Who Worked Through the Night: Analysis

January 19, 2015

ANN ARBOR, MI — Daytime PCI procedures performed by operators who were on call the night before are not associated with an increased risk of adverse events, such as a higher mortality, compared with procedures performed by operators who were not sleep-deprived, according to a new analysis of the National Cardiovascular Data Registry (NCDR)[1].

In fact, daytime PCI cases performed by operators who worked through the night were fairly uncommon, with just one in 40 cases performed by interventionalists who were on call the night prior.

"There are multiple studies that have shown sleep deprivation adversely impacts psychomotor and cognitive function," lead investigator Dr Herbert Aronow (St Joseph Mercy, Ann Arbor, MI) told heartwire . "The literature is mixed as to whether or not sleep deprivation negatively impacts patient outcomes, so we wanted to look at whether or not there might be an adverse relationship between performing middle-of-the-night PCI procedures and performing them the following day. We made the assumption that operators would be sleep-deprived if they had been up the night before doing the procedure."

A previous single-center study, which was considered too small and underpowered to be definitive, showed that PCI performed by sleep-deprived operators was not associated with an increased risk of mortality.

Given the unknowns, the current investigators performed an analysis of the NCDR CathPCI registry. Published January 19, 2015 in JACC : Cardiovascular Interventions, the analysis included 1 509 096 daytime PCI procedures performed by more than 5000 interventional cardiologists between 7 am and midnight from 2009 to 2012. Physicians were considered sleep-deprived if they performed a procedure from midnight until 6:59 am the night before starting their shift in the cath lab.

Overall, just 2.4% of daytime PCIs were performed by operators who performed at least one middle-of-the-night procedure. When the clinical outcomes of these operators were compared with interventionalists who did not work the night prior, the investigators saw no difference in the risk of bleeding or mortality for PCIs performed during the daytime. "Even though it's not common for operators to perform procedures after performing PCI procedures the previous night, when it did occur we found no signal of harm associated with doing so," said Aronow.

For operators who were considered chronically sleep-deprived—defined as having performed multiple middle-of-the-night PCI procedures during the previous 7 days—there was an increased risk of bleeding among their patients when they performed PCI the following day (odds ratio 1.19; P=0.007).

Chronic Sleep Deprivation and Bleeding

To heartwire, Aronow said it's possible for chronic sleep deprivation to affect bleeding rates, with a sleep-deprived physician making different decisions when tired. For example, a tired physician might select femoral over radial access or might fail to utilize other bleeding-avoidance strategies, such as vascular-closure devices. That said, although the finding of higher bleeding risks with chronic sleep deprivation is plausible, it is far from definitive and needs to be confirmed in another study, he added.

As for the bigger picture, such as potentially regulating physician workloads or mandating sleep, Aronow said the analysis suggests that the system appears to have evolved over time and corrected itself, evident in the relative infrequency at which operators work after a night doing PCIs. Also, the absence of a signal of harm suggests that there might be components within a clinical practice to prevent adverse outcomes.

"Operators might ensure they do have some sleep between a procedure in the middle of the night and one they perform the next day," said Aronow. "They might avoid scheduling certain types of procedures, or they might get some coverage from colleagues. They might be doing a number of things that we simply can't measure using the CathPCI registry data. One of the limitations is that we know what happened in the middle of the night, we know what happened the next day with the procedure, but we don't really know a lot about what happened in between."

Still, regardless of what remains unmeasured, the absence of harm for patients treated by sleep-deprived operators remains very reassuring, he added.

Do Not Make Bold Policy Changes Without Evidence

In an editorial[2], Dr Kirk Garratt (Lenox Hill Hospital, New York) pointed out that the Sleep Research Society has proposed requiring informed consent from patients if the operator has been awake for more than 22 hours. The NCDR data run counter to intuition and sleep science, but the results simply don't support policies or legislation that would limit physician privileges if they performed cases in the middle of the night. "We must conclude that policies restricting interventionalist access to the cath lab the day after [being on] call are not justified on the basis of safety-related evidence," he writes.

Garratt recommends diving deeper into the NCDR CathPCI registry data, "with a more granular assessment of the impact of physician and practice specifics," before any policies are enacted that would limit physicians working in the cath lab following a night on call.

It is interesting, he notes, to wonder why sleep deprivation appeared to have no impact on clinical outcomes. Have interventionalists adapted to a lack of sleep? Does a rested cath-lab team compensate for the very tired doctor? Is the margin of safety in angioplasty larger than previously imagined? The answers to these questions are unknown, but Garratt points out sleep research has suggested that deeply ingrained motor skills are less vulnerable to lack of sleep than newly acquired skills, even though efficiency might be compromised. In this way, maybe the repetitive habits in angioplasty aid in skill preservation, he wonders.

The study was funded by a grant from the American College of Cardiology Foundation NCDR.


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