Abstract
Background The Zwolle Risk Score was designed to identify the risk of complications in patients with ST-segment‒elevation myocardial infarction (STEMI) following percutaneous coronary intervention (PCI). Its utility following PCI in STEMI treated with thrombolysis is unknown. The objective was to evaluate the safety of using the Zwolle Risk Score to triage patients with STEMI following PCI, including patients receiving thrombolysis. Methods and Results Patients aged ≥18 years with STEMI and primary PCI or PCI after thrombolysis were included. A triage protocol was developed, with high-risk patients those with Zwolle Risk Score ≥4 triaged to the cardiac intensive care unit. A prospective evaluation of the triaging protocol was performed on 452 patients, mean age 65±12 years, 73% men. Median Zwolle Risk Score was 3 (interquartile range, 2‒5), with 257 low-risk (57%), and 195 high-risk (43%) patients. Adherence to the protocol was 91%. In-hospital mortality was 0.4% in low-risk and 13% in high-risk patients (P<0.001). Seventy-two patients (16%) received thrombolysis. Median time post-thrombolysis to PCI was 281 minutes (interquartile range, 219‒376). In-hospital mortality was 0% versus 9% (P=0.083) for low- and high-risk patients, respectively. High-risk patients had higher rates of cardiogenic shock (34% versus 1%, P<0.001), pulmonary edema (60% versus 9%, P<0.001), arrhythmia (25% versus 2%, P<0.001), blood transfusion (10% versus 2%, P<0.001), and stroke (4% versus 0.4%, P=0.011). Median hospital costs decreased by $1419 per low-risk patient after protocol implementation. Conclusions For patients with STEMI following primary PCI or PCI following thrombolysis, a Zwolle-based triaging system is safe and may decrease cardiac intensive care unit usage costs.