Outcomes of Patients Undergoing Cardiac Catheterization After a Three-Day Holiday Weekend Versus a Two-Day Weekend

Objectives. The study aim is to determine whether invasive cardiac procedures following a 3-day (holiday) weekend have worse outcomes compared with procedures following a 2-day (normal) weekend. Background. Catheterization laboratory schedules after 3-day holiday weekends tend to be overloaded with urgent procedures for patients who have waited up to 3 days. We hypothesized that this would be reflected by more procedural complications in patients undergoing procedures after a 3-day weekend. Methods. Invasive cardiac procedures that occurred after a weekend at Geisinger Medical Center from July 2012 to December 2019 were included. Baseline characteristics, presentation, periprocedural variables, adverse events, and clinical outcomes were compared between catheterizations on the day following a 2-day weekend and catheterizations following a 3-day weekend. Independent correlates of adverse events were identified by logistic regression analysis. Results. We identified 13,704 invasive cardiac procedures performed after a weekend, of which 722 occurred after a 3-day (holiday) weekend. Baseline demographics, presentation, and case volumes were similar between the 2 groups. Procedures after a 3-day weekend were not associated with any differences in in-hospital mortality, myocardial infarction, or stroke compared with those after a standard 2-day weekend. By univariate analysis, procedural complications were more frequent after a 3-day weekend (15.1% vs 12.3%; P=.03), but this difference was not significant on multivariate analysis (odds ratio, 1.22; P=.30). Conclusions. Cardiac catheterization procedures performed after a 3-day weekend were not associated with differences in in-patient mortality, myocardial infarction, stroke, or procedural complications.

J INVASIVE CARDIOL 2021;33(12):E939-E948. Epub 2021 November 3.

Key words: complications, off-hours, procedure delays, weekends

Despite the ability of a hospital to perform emergency procedures 24 hours a day, 7 days a week, 365 days a year, the availability of staff is limited during off hours compared with regular working hours. Our medical center specifically recognizes 6 national holidays on which normal operations are suspended and only urgent/emergent procedures are performed. When one of these days falls on a Friday or Monday, this leads to a three-day “holiday” weekend over which non-emergent and non-urgent procedures are not performed.

The long weekend may have several effects. First, patients with acute coronary syndrome (ACS) awaiting catheterization may have increased time to percutaneous coronary intervention (PCI) and an increased risk of mortality.^1-3 Second, reductions in weekend staffing may lead to a deficit in care.⁴ Finally, the backlog of cases accumulating over a 3-day weekend may tax resources available on the day following the weekend. Our study evaluated the last of these possible effects. We hypothesized that after 3-day weekends, compared with 2-day weekends, procedural volumes would be higher and that this might lead to changes in practice patterns (eg, fewer ad hoc PCIs) or increased periprocedural complications if operators were stressed or hurried by a postholiday surge in catheterization laboratory procedure volume.

Design and data sources. Cardiac catheterization laboratory procedures at Geisinger Medical Center after either a 2-day weekend or a holiday 3-day weekend from July 2012 to December 2019 were retrospectively included in this cohort study. Procedures were identified utilizing the hospital electronic medical record and the American College of Cardiology/Society for Cardiovascular Angiography and Interventions National Cardiovascular Data Registry (NCDR) CathPCI Registry hospital database. Procedures that met the inclusion criteria were divided into 2 groups: procedures on a Monday after a traditional weekend, or on the day after a 3-day weekend due to a holiday that would result in a contiguous 3-day weekend. The second group was further subdivided into catheterization on a Monday after a Friday-Saturday-Sunday weekend (F-S-S group) and those on a Tuesday after a Saturday-Sunday-Monday weekend (S-S-M group). The study was approved by the Geisinger investigational review board, which determined that patient consent was not necessary due to the retrospective nature of the study.

Standard practice patterns. At Geisinger Medical Center, patients admitted over a normal weekend (starting at 5 pm Friday and continuing until 7 am Monday) are treated with emergency catheterization if they present with ST-segment elevation myocardial infarction (STEMI) or very high-risk non-ST segment elevation myocardial infarction (NSTEMI) (including hemodynamic or electrical instability or ongoing chest pain) as recommended by guidelines. Patients admitted with stable low- or-moderate-risk ACS are treated with intravenous heparin, aspirin, beta-blockers, high-intensity statins, and in some cases, P2Y₁₂ inhibitors, with catheterization delayed until Monday. On a Monday after a 2-day weekend, 3-4 elective outpatients are scheduled for each of 2 catheterization laboratories, after which inpatient procedures are performed. The standard of care is to perform all needed procedures on the same day; it is very rare for a patient identified as needing a procedure on Monday to be delayed until the next day. Non-emergent catheterization laboratory procedures are rarely performed over the weekend.

Practice patterns over a holiday weekend are similar, with emergency cases performed promptly and non-emergent cases delayed until the next regular working day. The only difference is that after a holiday weekend, operators scheduled fewer elective outpatient procedures. Elective PCIs are generally not scheduled on the day following a 3-day weekend. Structural heart procedures were not scheduled on the day following either a 3-day or a 2-day weekend. Complete revascularization of non-culprit arteries in STEMI patients was generally not performed during the same admission during this study period, so it was very rare that a second staged PCI of a STEMI inpatient admitted over the weekend would be scheduled for the day after any weekend.

Study variables. Clinical data were extracted from the electronic medical record and included demographics, medical history, risk factors, medications, laboratory values, and left ventricular ejection fraction. Periprocedural variables including access site, procedure duration, contrast load, fluoroscopy times, and the type of intervention were extracted from the internal CathPCI Registry data. Insurance claims data were extracted for patients insured under Geisinger Health Plan

Clinical outcomes. Major outcomes of interest included in-hospital mortality, myocardial infarction, stroke, and periprocedural complications, including those tracked in the CathPCI Registry. Procedure status and disposition were also assessed.

Statistical methods. Analysis was on a per-procedure basis.  A total of 10,472 patients had 1 procedure, 778 patients had 2 procedures, 108 patients had 3 procedures, and 31 patients had a total of 4-6 procedures.

To examine differences between procedures done on the day after a 2-day weekend vs the day after a 3-day weekend, independent t-tests (continuous data) and Chi-square (categorical data) analyses were run. Frequency, percentages, means, and standard errors were reported. Because of the expected difference in sample size, equality of variances was examined. If that assumption was violated for t-tests, the Welch-Satterwaite equation was used to adjust the degrees of freedom and determine significance.

To examine differences in demographic characteristics between patients who had procedures on a 2-day weekend compared with a 3-day weekend, independent t-tests and Chi-square analyses were used. A detailed list of demographics and baseline characteristics are noted in Table 1. A P-value <.05 was statistically significant. A logistic regression was also run to examine whether demographic or patient history variables were associated with major adverse cardiac and cardiovascular events. All analyses were performed using SAS Enterprise Guide, version 8.2 (SAS Institute).

The study cohort included 13,704 patients, of which 12,982 (94.7%) underwent a catheterization laboratory procedure after a 2-day weekend and 722 (5.3%) underwent a catheterization laboratory procedure after a 3-day weekend. A total of 37 S-S-M and 6 F-S-S 3-day weekends occurred during the study period, with 655 patients and 67 patients, respectively, undergoing procedures on the following day.

Patients who had procedures following a 3-day weekend were less likely to have previous heart failure and atrial fibrillation compared with those who had procedures after a 2-day weekend. Demographic characteristics, including age, body mass index, gender, and ethnicity, in addition to prior history of coronary artery disease, diabetes, hypertension, dyslipidemia, renal failure, peripheral vascular disease, and cerebrovascular accidents were similar between the 2 groups (Table 1).

PCIs after a 3-day weekend were more likely to be ad hoc (81% vs 73% after a 2-day weekend) and less likely to be elective (8% vs 15%; P<.01) (Table 2). The percentage of diagnostic catheterizations that went on to ad hoc PCI tended to be higher after 3-day weekends (46% vs 42% for 2-day weekends; P=.06).

Procedure status (eg, urgent or elective) for diagnostic catheterizations and PCIs was similar for procedures after 3-day and 2-day weekends (Table 3), as was presentation of patients undergoing diagnostic catheterization and/or PCI (Table 4).

Intraprocedural variables, including fluoroscopy time, contrast volume, and utilization of left ventricular support, were similar between the 2 groups (Table 5). The percentages of patients requiring coronary artery bypass grafting (CABG) before discharge, length of stay, and procedural delay (time from admission to catheterization) were also similar between the 2 groups (Table 6). Analysis of insurance data revealed that disposition of patients undergoing a procedure after a 3-weekend, including discharge to a skilled nursing facility, home, or cardiac rehabilitation facility was similar to that following a 2-day weekend.

Compared with procedures performed after a 2-day weekend, those following a 3-day weekend were more likely to result in cardiac arrest (2.6% vs 1.2%; P<.01) and were more likely to be associated with any complication (15.1% vs 12.3%; P=.03) on univariate analysis (Table 7). In-hospital death, myocardial infarction, stroke, and the composite of these 3 adverse events were similar for 3-day vs 2-day weekends for patients undergoing diagnostic catheterization and for patients undergoing coronary intervention (Table 8).

Logistic regression analysis demonstrated that peripheral vascular disease, diabetes, use of P2Y₁₂ inhibitors, use of anticoagulants, fluoroscopy time, length of stay, interventional treatment, bypass surgery, and lack of statin therapy were associated with procedural complications or in-hospital adverse events (Table 9). However, 3-day vs 2-day weekend timing was not an independent correlate of the presence of any periprocedural complication.

The most important finding of this study is that there was no difference in in-hospital mortality, myocardial infarction, stroke, or procedural complications in patients undergoing catheterization after a 3-day weekend vs a 2-day weekend. This contradicts our hypothesis that complications would be increased after a 3-day weekend, perhaps because the operators were hurrying to complete a busy caseload or patients were more acute.

The second important finding of this study is that there was no difference in length of stay and no difference in delay to catheterization among holiday patients compared with normal weekend patients. Anecdotally, some patients admitted early on a holiday weekend waited an extra day (ie, Saturday, Sunday, and a Monday holiday) to undergo catheterization, which may have been reflected in a small numerical but statistically non-significant longer delay before catheterization.

The third important finding of this study is that while practice patterns were different after 3-day vs 2-day weekends (eg, fewer elective patients after 3-day weekends), there was no evidence that ad hoc PCIs were less frequent after 3-day weekends, as might be expected if operators were rushing to complete a busy caseload.  In contrast, the total number of diagnostic catheterizations and PCIs per day was similar for 3-day and 2-day weekends.

The “weekend effect” has been described as an increase in mortality of ACS patients admitted over a weekend and has been attributed to limited staffing, reduced access to healthcare, and lack of transportation.^2,5-11 Some studies have linked this to a lower rate of percutaneous revascularization done over weekends,^2,5-11 while others have attributed this increase in mortality to subgroups with various comorbidities,¹² and a few have not demonstrated any difference in mortality.^13,14 While this study did not evaluate adverse events in patients admitted over a weekend and waiting for catheterization until the day after the weekend, we hypothesized that the acuity of patients awaiting catheterization after a 3-day weekend might be higher and that this would translate into higher rates of procedural and postprocedural adverse outcomes.

Our study did not find any evidence that there were more procedures after 3-day weekends at this medical center, that operators deferred ad hoc PCIs after 3-day weekends, or that adverse events or procedural complications were increased after 3-day weekends. This suggests that practice patterns at our medical center were effective in preventing overwhelming surges in catheterization laboratory procedural volume after 3-day weekends. This is surprising, since it was the authors’ impression that the only strategy employed to mitigate surges after a 3-day weekend were to reduce the number of elective cases on the day after a 3-day weekend. The authors felt that other strategies that might have mitigated surges were not employed; specifically, a strategy of performing more non-emergent procedures over the 3-day weekend or deferring more cases from the day after to the second day after the 3-day weekend.

Adverse outcomes were independently associated with a history of peripheral vascular disease, diabetes mellitus, use of P2Y₁₂ inhibitors, use of anticoagulants, fluoroscopy time, length of stay, coronary intervention (compared with diagnostic catheterization alone), CABG, and lack of preprocedural statin use, as has been demonstrated in other studies of ACS patients.

Study limitations. It is important to consider the limitations of this retrospective study. It is a single-center study and results cannot be generalized. Results might be different for catheterization laboratories that avoid scheduling elective patients after a holiday weekend as a strategy to compensate for any increase in cases held over the weekend, or for less-experienced operators that might be less able to handle surges in case volume or acuity after 3-day weekends. While it was standard procedure to perform all needed catheterizations on the day after a weekend, we did not have any way to identify isolated cases that were deferred from the first postweekend day to the second postweekend day. We did not identify procedures performed on weekend days and thus were not able to determine if more non-emergent procedures were performed over 3-day weekends (although the authors agreed that they did not observe this). While data were captured prospectively, this is a retrospective study that does not account for all possible confounding factors. Important variables, such as Killip class, were not captured by our database. Long-term outcomes were not available. Finally, we did not study adverse events that occurred while awaiting catheterization over the 3-day or 2-day weekend, so we could not evaluate whether any “weekend effect” was present leading to adverse outcomes during the weekend, which might have prevented patients from being eligible for catheterization on the day following a weekend

This retrospective cohort study found no significant difference in in-hospital mortality, myocardial infarction, stroke, or periprocedural complications after a 3-day weekend compared with a 2-day weekend. Total procedural volumes were similar after 2-day and 3-day weekends, which was probably due to compensatory scheduling of fewer elective patients after 3-day weekends. We found no evidence that ad hoc PCIs were performed less frequently after 3-day weekends. While these findings are reassuring, they reflect an efficient system with experienced operators. We hope to test our hypotheses in larger datasets, such as the NCDR CathPCI Registry.

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