The mortality of ST-segment elevation acute coronary syndromes (STEACS) has decreased thanks to improved reperfusion times (fibrinolysis or primary angioplasty), so that, in daily practice, there is a greater number of patients with stable acute myocardial infarction (AMI).
This clinical stability and a low rate of complications raise the question of whether performing triage is necessary to avoid overusing beds in cardiac intensive care units (CICUs). This is particularly relevant due to an increasing shortage of physical operating capacity in healthcare facilities—particularly in critical care units—, a phenomenon that has been exacerbated by the COVID-19 pandemic.
The Zwolle score (SDZ) was initially designed to identify probable post-angioplasty complications (percutaneous transluminal coronary angioplasty, PTCA) in patients with STEACS. It is a useful and practical score for risk stratification in this population. Its variables are Killip status at admission, TIMI flow after intervention, age, three-vessel disease, previous infarction, and the presence of myocardial ischemia lasting more than four hours.
This score had been previously validated for early discharge after PTCA for STEACS, and for patient assessment for admission to telemetry wards according to risk. Its usefulness in patients who undergo PTCA after fibrinolytic therapy administration (rescue angioplasty or facilitated angioplasty) is currently unknown.
The aim of this prospective, single-center study was to evaluate the safety of SDZ for the triage of patients with STEACS after PTCA, including subjects who received fibrinolytic therapy prior to the intervention.
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With previously stipulated and validated thresholds, patients with SDZ ≥4 or cardiorespiratory arrest (CRA) on admission or in the cath lab, being admitted to a CICU after the intervention, were considered high risk. Patients with SDZ ≤4, admitted to a ward with telemetry available, were low risk.
The study included 452 patients with STEACS, aged 65±12 years, 73% of whom were men. Of these, 257 experienced SDZ ≤4 (low risk) and 195 SDZ ≥4 (high risk).
In the low-risk group, in-hospital mortality was 0.4%. Of these patients, 2% presented complications related to critical care, with an average hospitalization time of 3 days (RIC 2-3, p = 0.003). In the high-risk group, in-hospital mortality was 13%, with an average hospitalization time of 4 days (RIC 3-5), a higher rate of cardiogenic shock (34% vs. 1%), and of ventricular arrhythmia (25% vs. 2%), requiring some type of ventricular assistance during hospitalization (IABP, ECMO VA, etc.) in 4% of cases.
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In the subanalysis of patients who received fibrinolytic therapy, who accounted for 16% of the total (59% were for rescue angioplasty and 41% for the facilitated strategy), the high-risk group had higher in-hospital mortality and greater probability of cardiogenic shock.
Conclusions
SDZ is a useful and practical score for risk stratification in STEACS patients. There were no data available on a population receiving fibrinolytic therapy. Low-risk patients had lower mortality and fewer events. Its application could impact clinical decision making and treatment-associated costs. Using this tool could help to improve bed distribution, thus avoiding an eventual collapse of the system.
Dr. Omar Tupayachi.
Member of the Editorial Board of SOLACI.org
References: Parr CJ, Avery L, Hiebert B, Liu S, Minhas K, Ducas J. Using the Zwolle Risk Score at Time of Coronary Angiography to Triage Patients With ST-Elevation Myocardial Infarction Following Primary Percutaneous Coronary Intervention or Thrombolysis. J Am Heart Assoc. 2022 Feb 15;11(4):e024759. doi: 10.1161/JAHA.121.024759. Epub 2022 Feb 8. PMID: 35132867.
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