A new study from UCLA indicates that a widely used federal hospital safety metric, Patient Safety Indicator 04 (PSI 04), is flawed when applied to emergency stroke care. The findings suggest this metric may unintentionally discourage hospitals from performing critical procedures for the sickest patients. The research was published in the Journal of NeuroInterventional Surgery. A team examined data from the Nationwide Inpatient Sample, covering 73,580 stroke thrombectomy procedures between 2016-2019, alongside detailed case reviews from UCLA.
Metric Application
The study noted that PSI 04, a "failure-to-rescue" measure by the U.S. Agency for Healthcare Research and Quality (AHRQ) designed to track deaths after treatable surgical complications, is appropriate for elective procedures on relatively healthy patients. However, it was found to be unsuitable for endovascular thrombectomy, an emergency procedure for stroke patients who are often critically ill upon hospital admission.
Dr. Melissa Marie Reider-Demer, the study's first author, stated that when applied to emergency stroke care, the metric flags unavoidable complications from severe strokes rather than issues with the procedure itself. This could result in hospitals providing excellent stroke care appearing to have poor safety records.
PSI 04 is triggered by five post-procedure complications (pneumonia, blood clots, sepsis, shock/cardiac arrest, or gastrointestinal bleeding) leading to hospital death. The metric is used nationally for public reporting, hospital quality ratings, and pay-for-performance programs by Medicare and organizations like the Leapfrog Group.
Key Findings
Analysis of national data and UCLA case reviews revealed several points:
- PSI 04 occurred in 20.5% of stroke thrombectomy patients nationally, which is significantly higher than other patient safety indicators (median: 0.10%).
- The rate for stroke procedures was higher than the 14.3% rate for all surgical procedures combined.
- Among 18 federal patient safety indicators, PSI 04 for all procedures had the highest event rate.
At UCLA's Comprehensive Stroke Center, an expert panel reviewed every thrombectomy case flagged by PSI 04 from 2016-2018. The review concluded:
- All patient deaths were linked to complications of the severe presenting stroke, not the thrombectomy procedure.
- Endovascular thrombectomy (EVT) procedures accounted for 7.2% of neurosurgical PSI 04 flags, despite representing only 1.5% of neurosurgical procedures.
- No cases identified actual preventable safety concerns.
Reasons for Flaws and Consequences
The study identified two main reasons for the metric's flaw in stroke thrombectomy:
- The complications tracked are common consequences of severe strokes themselves, independent of the procedure. Patients with massive strokes face high risks for complications regardless of treatment.
- Stroke patients are often critically ill before the procedure and have less resilience to survive complications compared to healthier surgical patients.
Dr. Reider-Demer noted that the system essentially penalizes hospitals for attempting to save patients who are already in critical condition due to stroke. This could lead to hospitals being discouraged from performing thrombectomy on the most severe stroke patients, or stroke centers with high volumes of critically ill patients being unfairly penalized in quality ratings and reimbursement. This concern is heightened as recent clinical trials have expanded thrombectomy to patients with even larger strokes, who have high mortality rates even with intervention.
Path Forward
The Centers for Medicare & Medicaid Services has proposed revising PSI 04 to exclude patients with acute conditions like stroke coded as the primary reason for admission. Implementation is planned for fiscal year 2027. Dr. Jeffrey Saver, the study's senior author, stated that this revision aligns with clinical understanding, prevents misrepresentation of hospital quality, and aims to avoid creating incentives that could negatively impact the sickest patients.