Why are eligible thrombolysis candidates left untreated?

BACKGROUND: Despite proven efficacy, thrombolytics are used in a minority of eligible candidates. Because some of the exclusion criteria are vague, relying on documented contraindications could disguise biases in usage. This study sought to identify barriers to tissue-type plasminogen activator (tPA) treatment among eligible patients with acute ischemic stroke.
METHODS: The study prospectively identified all patients with an initial diagnosis of ischemic stroke arriving within 2.5 hours of symptom onset at 11 hospitals participating in the Centers for Disease Control and Prevention-sponsored California Acute Stroke Prototype Registry during two 3-month periods in 2002 and 2003. Potential risk factors for nontreatment with thrombolytics among patients categorized as eligible were examined, based on directly documented contraindications. Analyses were repeated after reclassification of eligibility based on record review.
RESULTS: Of 625 patients with ischemic stroke, 126 (20%) arrived at the emergency department within 2.5 hours of symptom onset. Based on direct documentation, 72 (11.5% of all patients; 57% of in-time arrivals) were eligible for thrombolysis; 32 (44% of eligible patients) who received tPA within the 3-hour time window and 40 who did not receive thrombolytic medications despite having no documented contraindication to treatment. Factors predictive of nontreatment were older age (p=0.0005), later arrival (p=0.004), and admittance to a non-academic hospital (p=0.03). After record review, slightly fewer patients (n=61) were deemed eligible, with a tPA treatment rate of 52% among those eligible. Older age (p=0.002) and later arrival (p=0.002) continued to be predictive of nontreatment with thrombolytics after reclassification.
CONCLUSIONS: Even when more-comprehensive eligibility standards are applied, older age and later hospital arrival are associated with nontreatment with thrombolytics.