Weekend Warriors: Can Early Invasive Management of Stable Non–ST-Elevation Acute Coronary Syndromes Save Health Care Dollars?

Economic analyses in health care encompass a variety of analytical techniques, ranging from pure cost analyses to complex cost-effectiveness modelling. Most interventions in health care are associated with additional health benefits, measured in additional years of life, improved quality of life, and prevention of complications, yet many of these interventions, particularly within the cardiovascular space, come with a significant financial burden.

Typically, policy makers must make sometimes-difficult choices between competing programs that all offer some benefit at some cost with the goal of maximizing benefit to society as a whole. Health economists have the role of determining the value of a given intervention to guide policy-makers. For example, the use of implantable cardioverter defibrillators in patients with depressed left ventricular systolic function improves survival when used for the primary prevention of malignant arrhythmias, albeit with substantial device-related costs. The cost-effectiveness ratio, ranging from $34,000 (USD) to $70,200 (USD) per quality-adjusted life year across all published trials, is a commonly accepted expression of value in health care and could be regarded as the cost that society is willing to pay for prolonging or improving the lives of patients. Indeed, most public and private payers choose to reimburse the cost of implantable cardioverter defibrillators for this indication.

Occasionally, the choice is a much clearer one. Health economists, like anyone else, would consider an intervention that resulted in benefit (eg, a gain in longevity) while also saving health care dollars a “no brainer.” Health economists call this a dominant strategy. Primary percutaneous coronary intervention (PCI) vs fibrinolysis in the treatment of ST-elevation myocardial infraction (STEMI) and PCI with drug-eluting stents vs conventional coronary bypass surgery for isolated left main disease are examples of so-called economically dominant strategies. A similar scenario is 2 competing treatment strategies that yield equivalent clinical outcomes, but one is associated with potential cost savings compared with the other.

In this issue of the Canadian Journal of Cardiology, Lamy and colleagues performed a detailed cost analysis of the large international Timing of Intervention in Acute Coronary Syndromes (TIMACS) trial that compared early (within 24 hours) vs delayed (after 36 hours) invasive management of non-ST-elevation acute coronary syndrome (NSTEACS) patients from a Canadian health care perspective. As previously reported, delaying the catheterization in this trial was not associated with increased risk compared with an earlier strategy in the overall population. The authors hypothesized that the earlier intervention strategy, by enabling more rapid hospital discharge, could result in cost savings. However, it was also considered that to provide earlier catheterization, a proportion of patients would be required to have their studies performed on weekends, when the cardiac catheterization laboratory (CCL) is not normally operating. The median catheterization delay in the early group was 14 hours. This represents a ‘same-day’ or ‘next-day’ catheterization time frame for most patients, compared with a median of 50 hours in the delayed group. Lamy et al. showed that earlier invasive management of NSTEACS was associated with a savings of $2,938 (CAD) per patient and economies in length of stay (LOS) accounted for 96% of the cost reduction observed. In a sensitivity analysis, the authors appropriately considered the additional cost of operating the CCL on weekends, including nursing time and physician fee premiums, and showed that the early invasive strategy in TIMACS remained cost-saving even if 50% of all NSTEACS cases were to be performed on weekends. Additionally, it was assumed that when activated, the CCL would cost 4 hours of work per activation, when in reality 2 or more such cases could be performed during that time, which speaks to a certain robustness of the results. Although sensitivity analyses are not specifically reported around the physician and nursing costs for weekend cases, their assumptions are reasonable and reflect current practice.

These findings are consistent with previous literature; reducing the post-PCI LOS is also associated with economies. In the single-centre Early Discharge After Transradial Stenting of Coronary Arteries (EASY) trial, Rinfret and collaborators showed that same-day discharge after an uncomplicated PCI was associated with cost savings without additional clinical risk. It is worth mentioning that most patients in this latter study also presented with NSTEACS, and that the cost savings attributed to early hospital discharge were similar compared with the analysis of Lamy et al.

Lamy et al. claim that their findings support opening CCL on weekends to facilitate the use of early invasive intervention in all patients. Although the evidence for cost savings using an earlier catheterization strategy certainly appears robust, the author's conclusions about the need to mobilize the CCL team during weekends for patients with NSTEACS merit further discussion.

First, Lamy et al. do not provide the exact proportion of cases performed during weekends vs weekdays in TIMACS. Hence, the sensitivity analysis on weekend volume remains speculative and therefore less informative for policy guidance.

Second, TIMACS confirmed previous data, in that delaying catheterization in NSTEACS does not add any clinical benefit (in terms of plaque stabilization, for example), thus, failing to justify the extra costs of extended in-hospital antithrombotic treatment. As a result of these data and the decreasing global volume of cardiac catheterization, coupled with a competitive environment to perform these procedures in large urban centres, invasive cardiology services have already undertaken reasonable efforts to perform clinically indicated coronary angiography as early as possible in most patients. There is, therefore, the potential for a more insidious limitation of the current analysis. As a result of the original trial design, some NSTEACS patients in the delayed group, who could and indeed would have been normally managed during the week of their admission (ie, earlier), might have been forced to wait quite a bit of time for their procedure according to constraints of the trial.

For example, in many Canadian centres, when a patient is admitted on a Thursday and needs cardiac catheterization, all efforts are made to perform the test on the next day to avoid delaying coronary angiography until the following Monday and the associated significant increase in LOS. In TIMACS, there was no upper limit to the wait for the delayed group, because the protocol required only a prescribed minimum delay of 36 hours before the catheterization. The result is that, in TIMACS, patients admitted on Thursday and randomized to the delayed strategy were not permitted to undergo catheterization on Friday. Patients in this group were necessarily scheduled for the next regular slot on Monday unless they became unstable, representing an increase in LOS of up to 4 days compared with standard care for this particular example. In other words, early invasive management of NSTEACS is better, from an economic standpoint, than unwarranted delays. However, it is less clear that the economic effect of the early catheterization strategy tested in TIMACS over what is currently being done in Canadian centres would be as great, let alone justify the opening of CCLs on weekends for the express purpose of performing nonemergent cases.

As a final comment, let us assume for the moment that the scientific evidence for opening CCLs on weekends for invasive management of NSTEACS was sound. There remain a number of factors to consider before the widespread institution of a policy of weekend catheterizations for nonurgent NSTEACS. Most Canadian hospital departments deliver services with annual budget constraints that are by design somewhat independent of other departments' budgets (so-called “silo budgets”). Using this model, mobilizing the on-call team, usually funded by CCL budgets (to finance off-hours salaries) to treat patients who are clinically stable to reduce LOS, funded by another silo outside of the cardiology department, might not be perceived favourably by CCL administrators and cardiology departments alike. Also, with on-call teams already substantially mobilized for STEMIs, additional weekend workloads might lead to nurse and technician absenteeism on Mondays, which in turn could negatively affect the volume and efficiency of CCL work early during the regular working week. Likewise, the attitudes of interventional cardiologists who perform those nonurgent cases during weekends might need to be addressed, because there might indeed be lingering doubt as to the clinical merit of such a strategy that might be incompletely assuaged by any extra reimbursement for performing weekend cases. Worse, some studies have shown that performance of off-hour cases is associated with increased risk for the patient, especially in the STEMI setting. It is entirely possible that, not only might NSTEACS cases performed on weekends not result in the same benefits as procedures performed by a fresh and rested interventional team on Monday, they could also inadvertently lead to decreased benefit for STEMI cases performed during “on-call” hours. Finally, ‘slowing down’ during the weekends is not unique to CCL; many other hospital services work with reduced staff and simply cover emergencies during the weekends. It is likely that if cardiac surgery services would mobilize the on-call team for procedures in stable NSTEACS patients, LOS would likely be significantly reduced. However, it would be very hard to sell such a strategy to stakeholders even if this approach was ultimately cost-saving, because its generalization to other areas could become practically unmanageable.

In summary, how much money can our health care system save with an earlier invasive management of otherwise nonurgent NSTEACS on weekends? Ultimately, we conclude that we still do not know and the data do not support the systematic performance of nonurgent NSTEACS on weekends for the time-being. The study from Lamy et al. does however, confirm 2 important messages. First, LOS is indeed an important financial consideration in the evaluation of patient care strategies, including NSTEACS. Second, avoidable catheterization delays are unwarranted and only lead to unnecessary increases in hospitalization costs. It would therefore seem reasonable, if the team is already mobilized for a weekend STEMI, to consider performing 1 or 2 additional NSTEACS cases awaiting catheterization, particularly in patients at greater than average risk and without other obstacles to discharge. Ultimately, any economic benefit (which remains an open question) of performing these cases on weekends must be weighed against its potential negative effect on already-stretched weekend call teams, including on morale, health care workers' physical or mental health, and, possibly and most importantly, patient safety.