Association between Hospital Cardiac Catheter Laboratory Status, use of an Invasive Strategy and Outcomes after NSTEMI

Background: While previous studies report increased use of invasive coronary strategy in patients admitted to hospitals with onsite cardiac catheter laboratory (CCL) facilities, the utility of invasive coronary strategy according to types of CCL facilities at the first admitting hospital and clinical outcomes is unknown.
Methods: We included 452,216 patients admitted with a diagnosis of NSTEMI in England & Wales between 2007-2015. The admitting hospitals were categorized into; no-laboratory, diagnostic and PCI hospitals according to CCL facilities. Multilevel logistic regression models were used to study association between CCL facilities and in-hospital outcomes.
Results: 97,777 (21.6%) were admitted to `no laboratory` whereas 134,381 (29.7%) and 220,058 (48.7%) patients were admitted to `diagnostic` and PCI hospitals, respectively. Use of coronary angiography was significantly higher in PCI hospital (77.3%) compared to `diagnostic` (63.2%) and `no laboratory` (61.4%) hospitals. The adjusted odds of in-hospital mortality were similar for `diagnostic` (OR 0.93 95%CI 0.83-1.04) and PCI hospitals (OR 1.09 95%CI 0.96-1.24), compared to `no laboratory` hospitals. However, in high-risk NSTEMI (defined as GRACE score>140) subgroup, an admission to `diagnostic` hospitals was associated with significantly increased in-hospital mortality (OR 1.36 95%CI 1.06-1.75) compared to `no laboratory` and PCI hospitals. 
Conclusions: Our study highlights important differences in both the utilisation of invasive coronary strategy and subsequent management of NSTEMI patients according to admitting hospital CCL facilities. These variations are important particularly in the high-risk NSTEMI where patients admitted to ‘diagnostic’ hospitals had greater risk of in-hospital mortality.