Volume,outcomes,and ‘Centers of Excellence’ for pulmonary embolism care

Pulmonary embolism (PE) affects patients across many disciplines of medicine and surgery, and its management may vary according to experience and expertise among treating providers. Although there has been growing interest in the establishment of PE response teams (PERTs) to streamline the care of patients with high-risk PE, such coordinated care is present in only a small minority of the over 4000 hospitals in the United States. ¹ Meanwhile, the care for other acute cardiovascular conditions (e.g. acute myocardial infarction, stroke) is typified by a coordinated, evidence-based, team approach. Favorable clinical outcomes for these conditions has also been associated with inpatient hospital volume of the disease processes.^2,3 For PE, which is largely managed in a less regimented fashion at most hospitals, it is unknown whether there is a favorable relationship between the number of patients with PE treated at an institution and improved outcomes.

In this edition of Vascular Medicine, Finkelstein and colleagues performed an observational analysis of the New York Statewide Planning and Research Cooperative System (SPARCS) database focused on PE admissions between 2009 and 2015. ⁴ They stratified hospitals according to low (< 52 cases/year), medium (52–87 cases/year), high (88–147 cases/year), and very high (> 148 cases/year) inpatient PE volumes. Using multivariable regression modeling accounting for demographic and illness severity variables among these four cohorts of PE volume, the investigators assessed length of stay, 30-day or PE-related readmission, 1-year all-cause mortality, and total charges. They discovered that higher volume hospitals were more likely urban, academically affiliated, and cared for patients with higher illness severity. Following adjustment, a ‘very high’ volume of PE encounters was associated with 16% lower 30-day readmissions, a 36% reduction in 30-day PE-related readmissions, and 15% reductions in 1-year mortality, with a 6% reduction in length of stay and 4% lower costs in comparison to low volume centers.

These data correlate with another recent study also demonstrating associations between increased hospital volume and improved outcomes among hospitalized patients treated for PE in Europe. ⁵ The recent elucidation of a volume–outcome relationship in management of PE thus mirrors the findings for overall management of other acute cardiovascular conditions, as well as those for more targeted procedural management of several cardiovascular and non-cardiovascular conditions.^2,3 However, expert clinicians in the field recognize that volume alone is not a panacea when attempting to judge the quality of care at a given institution. Furthermore, prioritization of volume as a metric for quality is often in direct conflict with the need for readily available access to care for urgent conditions such as PE, particularly in rural areas.

It is in this setting that various entities including insurance providers, professional organizations, patient advocacy organizations, and dedicated physician/hospital rating companies have aimed to create ‘Centers of Excellence (COE)’ designations for hospitals for certain conditions, procedures, or entire specialties. Criteria for designation by these assorted entities are highly variable, and objective evaluation of their correlation with outcomes is often absent. For example, a recent study of COE designation for percutaneous coronary intervention by three New York state insurance companies did not find reliable correlations between COE designations and objective clinical outcomes of the procedures. ⁶ So what is it that makes a center ‘excellent’ with regards to PE care? A recent white paper by Elrod and Fortenberry ⁷ identified six distinguishing features that could be used to designate a COE: (i) organizational design, (ii) personnel, (iii) servicescape design, (iv) cutting edge therapy, (v) marketing, and (vi) financial impact. We can try to apply their framework to PE care to evaluate whether the field may be ready for COE designations.

Organizational design and personnel. Historically, providers across disparate specialties managed PE on their own, without a formalized system of care delivery. In recent years, multidisciplinary PERTs have developed around the country in recognition of this unmet need. ¹ As an example, a PE program may bring together specialists from vascular medicine, pulmonary medicine and critical care, hematology, interventional cardiology, and cardiac surgery to weigh in on the optimal treatment of a single patient with PE. ⁸

Cutting edge medical care and servicescape design. COE must be able to deliver cutting edge medical care and include the capacity to employ the full range of therapeutic options for advanced PE care. These may include: catheter-directed thrombolysis, catheter-based embolectomy, surgical pulmonary embolectomy, extra-corporeal membranous oxygenation (ECMO), and percutaneous and surgical right ventricular assist device (RVAD) platforms. PERT teams have been shown to utilize advanced PE therapies more frequently and have overall been associated with significant improvement in several ‘process’ metrics, such as time to diagnosis, time to therapeutic anticoagulation, and length of stay.^9–11 PERT teams also serve as a platform for ongoing quality improvement and clinical research at the hospital level.

Marketing and financial impact. If both PERT teams and ‘very high’ volume centers truly provide shorter hospital stays, better utilization of resources, and improved outcomes, these would likely translate to improvements in both cost-effectiveness and quality of life. If confirmed with objective research, such findings would bolster the case for greater inter-institutional collaborations to establish clear lines of transfer from a peripheral network of hospitals to a central, specialized, higher volume center (i.e. the ‘hub-and-spoke’ model).

It is clear that the presence of a PERT team fulfills many of the criteria designated by Elrod and Fortenberry for COE. The present group of authors all practice at member institutions of the PERT Consortium (https://pertconsortium.org/), a potential candidate for addressing COE in PE. This 501(c)(3) not-for-profit organization has broad representation in multiple domains including community/academic settings, urban/rural areas, and every region of the US. Furthermore, the PERT Consortium offers unique opportunities to devise and deploy multicenter prospective registries or clinical trials dedicated solely to PE care. However, the mere presence of a PERT team at an institution does not address the myriad challenges that would need to be addressed when considering the development of a fair and equitable COE designation system.

For example, glaringly absent in the above criteria from Elrod and Fortenberry is a discussion of process outcomes, clinical outcomes, or hospital volume. The PERT Consortium has an actively enrolling national registry that could be used to assess such factors, but such efforts are often associated with the pitfalls of devising valid risk adjustment schemes and adjudicating submitted data. Additionally, data from the present study by Finkelstein et al. would seem to incentivize a ‘hub-and-spoke’ model of PE care, with more complex patients being quickly shunted to higher volume, higher resource centers. While the present study provides an initial examination into volume thresholds, considerably more research would be needed to fully elucidate the appropriate cutpoints that might be codified in a COE designation framework. ⁵ Furthermore, it should be noted that, in addition to access to care considerations, there may be potential financial disincentives to this framework for smaller ‘spoke’ hospitals, particularly as potential high-reimbursement interventional procedures related to acute PE management mature. How would an organization without the ‘power of the purse’ influence realignment of such incentives in a way that encourages broad participation in a COE effort? If achieved, how would this also avoid blatant regulatory capture through partnerships with payers that may then create conflicts with member institutions? Finally, COE designation represents a major policy effort for the field. If undertaken, it will be important that stakeholders recognize the power and possible unintended consequences of a novel COE designation for PE, with such an intervention being held a priori to the same standards of safety and efficacy that we would hold a therapeutic intervention.