Applicability of the Zwolle score for selection of very high-risk ST-elevation myocardial infarction patients treated with primary angioplasty

The Zwolle risk score was designed to stratify in-hospital mortality risk of ST-elevation myocardial infarction (STEMI) patients treated with primary percutaneous coronary intervention (pPCI) and for decision-making in the unit where patients are admitted. We assessed the accuracy of Zwolle risk score for in-hospital mortality estimation compared with the GRACE score in all patients (n = 4446) admitted for STEMI in 3 university hospitals. Only one fourth of the patients were classified as high-risk by the Zwolle risk score vs 60% by the GRACE score. In-hospital mortality was 10.6%. A statistically significant increase in in-hospital mortality, adjusted by age, gender, and revascularization, was observed with both scores. The assessment of the optimal cut-off points verified the accuracy of Zwolle score ≥4 as optimal threshold for high-risk categorization. In contrast, GRACE score ≥140 had very low specificity as well as percentage of patients correctly classified; GRACE score ≥175 was fairly better. The reclassification index of the Zwolle score after applying the GRACE score was 35.5%. Selection of high-risk STEMI patients treated with pPCI based on the Zwolle risk score has higher specificity than the GRACE score and might be useful in clinical practice.

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

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.

Zwolle Risk Score for Safety Assessment of Same-day Discharge after Primary Percutaneous Coronary Intervention

OBJECTIVES

The Zwolle risk score (ZRS) has been considered to be a useful tool for the systematic evaluation of patients for early discharge after primary percutaneous coronary intervention (PCI). Therefore, aim of this study was to evaluate the clinical utility of ZRS for the same-day discharge strategy after primary PCI at a tertiary care cardiac center of Karachi, Pakistan.

METHODS

This study was conducted at a tertiary care cardiac center between August 2019 and July 2020. Patients discharged within 24 h (same-day) of the primary PCI procedure were included. Patients were stratified as high- and low-risk based on ZRS score; low-risk (≤3) and high-risk (≥4). All patients were followed during 30-days post-procedure period for major adverse cardiac events (MACE).

RESULTS

Out of 487 patients, 83.2% (405) were male and mean age was 54.6 ± 10.87 years. Mean ZRS was 2.34 ± 1.64 with 16.0% (78) patients in high-risk (≥4) group. 30-days MACE rate was observed to be 5.3% (26) with significantly higher rate among high-risk patients as compared to low-risk patients 12.8% (10) vs. 3.9% (16); p = 0.004 respectively with OR of 3.61 [1.57-8.29]. The area under the curve (AUC) of ZRS for prediction of 30-day MACE was 0.67 [95% CI: 0.58-0.77], ZRS ≥4 had sensitivity of 38.5% and specificity of 85.2% with AUC of 0.62 [95% CI: 0.50-0.74] for prediction of 30-day MACE.

CONCLUSION

ZRS showed moderate discriminating potential in identifying patients with high-risk of MACE at 30-day after same-day discharge after primary PCI.

Utility of Zwolle Risk Score in Guiding Low-Risk STEMI Discharge

BACKGROUND

Despite emerging evidence suggesting that selected patients presenting with ST-segment elevation myocardial infarction (STEMI) treated successfully with primary percutaneous coronary intervention (PPCI) may be considered for early discharge, STEMI patients are typically hospitalised longer to monitor for serious complications.

METHODS

We assessed the feasibility of identifying low-risk STEMI patients in our institution for early discharge using the Zwolle risk score (ZRS). We evaluated consecutive STEMI patients who underwent successful PPCI within the period 1 January 2016 to 31 December 2017. Low-risk was defined as ZRS≤3. Demographic, angiographic characteristics, length of stay (LOS), and 30-day major adverse cardiovascular events (MACE) defined as cardiac death, stroke, congestive cardiac failure, and non-fatal myocardial infarction, were recorded.

RESULTS

There were 183 STEMI patients in our study cohort (mean age 62.0±12.2 years, 77.0% male). The median ZRS was 2 (interquartile range 1-4) with 132 (72.1%) patients classified as low-risk. The overall 30-day MACE and mortality rates were 10.4% and 3.3% respectively. None of the 35 (26.5%) low-risk patients who were discharged within 72 hours experienced MACE at 30 days. Low-risk STEMI patients had significantly shorter median LOS (86.3 vs. 93.2 hours, p=0.002), lower 30-day MACE (4.5% vs. 25.5%, p<0.0001) and mortality (0% vs. 11.8%, p<0.0001) compared to high-risk group (ZRS>3). Receiver operating characteristic (ROC) curve analyses for ZRS in predicting 30-day MACE and mortality yielded C-statistics of 0.79 (95%CI 0.68-0.90, p<0.0001) and 0.98 (95%CI 0.95-1.00, p<0.0001) respectively.

CONCLUSION

Low-risk STEMI patients stratified by Zwolle risk score, who were treated successfully with PPCI, experienced low 30-day MACE and mortality rates, indicating that early discharge may be safe in these patients. Larger studies are warranted to evaluate the safety of ZRS-guided early discharge of STEMI patients, as well as the economic and psychological impacts.

Applicability of the Zwolle risk score for safe early discharge after primary percutaneous coronary intervention in ST-segment elevation myocardial infarction

INTRODUCTION AND AIM

The optimal length of stay for patients with uncomplicated ST-segment elevation myocardial infarction (STEMI) treated with primary percutaneous coronary intervention (PPCI) is still undetermined. The Zwolle risk score (ZRS) is a simple tool designed to identify patients who can be safely discharged within 72 hours. The purpose of this study was to assess the applicability and performance of the ZRS in our population.

METHODS

We studied 276 consecutive patients (mean age 62 ± 14 years, 75% male, 20% Killip class >1) admitted over a two-year period for STEMI and treated with PPCI. ZRS, length of stay, 30-day mortality and readmission were obtained for all patients. Low risk was defined as ZRS ≤ 3.

RESULTS

The median ZRS was 3 (interquartile range [IQR] 1-4), with 171 patients (62%) being classified as low risk. Thirty-day mortality was 4.7% (13 patients). Compared to other patients, low-risk patients had shorter length of stay (median 5.0 [IQR 4-7] vs. 7.0 [5-13] days, p<0.001), and lower 30-day mortality (0 vs. 12.4%, p<0.001), yielding a negative predictive value of 100% (95% CI 97.0-100%) for the proposed cutoff. The ZRS showed excellent discriminative power (C-statistic: 0.937, 95% CI 0.906-0.968, p<0.001), and good calibration against the original cohort.

CONCLUSIONS

The ZRS appears to perform well in identifying low-risk STEMI patients who could be safely discharged within 72 hours of admission. Using the ZRS in our population could result in a more rational use of in-patient resources.