35 Zwolle Risk Score Identifies Low Risk Category Patients Who are Safe for Early Discharge After Primary PCI for Acute Myocardial Infarction

Abstract

Introduction Primary percutaneous coronary intervention (PPCI) is the preferred strategy for revascularisation after acute ST elevation myocardial infarction (STEMI) in most of United Kingdom. There is no uniform guidance on the early safe discharge of these patients after PPCI. We explored the safety and feasibility of early discharge (48 h) after PPCI using the Zwolle score criteria. Zwolle score is a well-validated tool for risk stratification first described in the pre PPCI era. Zwolle risk score uses 6 clinical variables to calculate risk. Patients with a low risk score (≤ 3) are considered for safe for early discharge. Materials and methods Royal Cornwall hospital adopted 24/7 PPCI for the treatment of acute STEMI from January 2011. We conducted a retrospective study of 422 consecutive patients over a two year period (1 February 2011 to 31 January 2013) compared the actual length of hospital stay versus the predicated length of stay based on the Zwolle risk score. We also calculated the cost savings from the proposed strategy. Results The important demographic features of the three groups are shown in Table 1. Abstract 35 Table 1 Zwolle category (n) ≤ 3 (298) >3- <10 (80) ≥ 10 (44) Mean age (y) 60.8 67.9 65.8 Males (%) 239 (82.5) 55 (65.5) 22 (50) Hypercholesterolaemia (%) 69 (23.2) 18 (21.5) 9 (22.5) Hypertension (%) 112(37.7%) 33 (39.3%) 16 (40%) Diabetes (%) 24 (8.1) 7 (8.3) 10 (25) Family history (%) 136 (45.8) 29 (34.5) 3 (7.5) The mortality from the 3 different risk category is shown in Figure 1. Abstract 35 Figure 1 The total length of stay for the low risk group was 1248 days (mean 4.2) and the predicted total length of stay was 596 days, thus giving predicted reduction of652 days. This equates a cost saving ofbetween 142,800 and 337,365 pounds per year. Conclusion The Zwolle risk score is an easily usable clinical tool and it clearly identifies a low risk population who could be safely discharged in 48 h after PPCI. The adoption of Zwolle risk score based discharge will result in significant cost savings.