Authors (including presenting author) :
CY Wong (1), MC Chan (1), J Chan (2), SF Chui (1), KC Chan (1), CL Fu (1), CM Lo (4), CK Wong (3), LW Tam (2), KY Lee (1), KT Chan (1)
Affiliation :
(1) Division of Cardiology, Department of Medicine, Queen Elizabeth Hospital, Hong Kong (2) Division of Cardiology, Department of Medicine and Geriatrics, Kwong Wah Hospital, Hong Kong (3) Department of Accident and Emergency, Queen Elizabeth Hospital, Hong Kong (4) Department of Accident and Emergency, Kwong Wah Hospital, Hong Kong
Introduction :
Primary percutaneous coronary intervention (PPCI) is the preferred reperfusion strategy over thrombolysis in patients with ST-segment elevation myocardial infarction (STEMI) in various international guidelines. Starting from October 2018, Queen Elizabeth Hospital (QEH) has extended the PPCI service from weekday 8 am to 8 pm period to 24-hour service including weekends and holidays. STEMI cases presented to other Accident and Emergency Department (AED) within Kowloon Central Cluster region, namely Kwong Wah Hospital (KWH), outside operating hours would also be transferred to QEH for PPCI (secondary diversion).
Objectives :
This study aims to review the feasibility and outcome of this first cluster-based 24-hours PPCI program over 1 year period.
Methodology :
When patients present with chest pain and electrocardiographic features of suspected STEMI, the “STEMI Call” will be triggered. AED physician, AMI nurse and senior cardiologist will jointly assess the patient and decide the management plan. Eligible patients presented to QEH AED or in-patient wards (at all times), and KWH AED (outside weekday 8 am to 8 pm) will be transferred to the Cardiac Catheterization Laboratory (CCL) of QEH for PPCI. Consecutive cases of STEMI with PPCI performed in Queen Elizabeth Hospital after commencement of 24-hour PPCI program were analyzed (between 8th October 2018 and 30th November 2019).
From 8th October 2018 to 30th November 2019, there were 581 “STEMI Call” activations. After joint assessment by AED physician, AMI nurse and senior cardiologist, 431 patients (74.2%) were transferred to CCL for coronary angiogram. Among them, 363 (84.2% of 431) patients were diagnosed to have obstructive coronary artery disease that required PPCI. The outcome of these patients were analyzed.
Result & Outcome :
Of the 363 PPCI patients, male comprised of 77.4% and were younger than female (62.5years vs. 74.2years, p< 0.001). The mean AED door to balloon (DTB) time was 89.3 mins. There were no significant differences between QEH AED and secondary diversion cases (87.2mins vs. 95.5mins, p=NS), and between cardiogenic shock (CS) and non-CS cases (88.8mins vs 87.9mins, p=NS). However there was difference for patients presented at weekdays 8am–8pm vs. other time (80.9mins vs 92.5mins, p=0.01) . 46 patients (12.7%) presented with CS. There was significant in-hospital mortality difference between CS and non-CS patients (47.8% vs. 8.2%, p< 0.001). Excluding CS patients with cardiac arrest (12 patients) before PPCI, the mortality of CS patients without cardiac arrest was 35.3%. There were no significant differences in in-hospital mortality in terms of gender, presentation time (weekday 8am to 8pm or not) and source hospital. For patients surviving the index admission, there were 2 additional mortality cases at 30-days. All clinically indicated cases of STEMI received PPCI as reperfusion therapy and no thrombolysis was given during this period. Compared with STEMI patients receiving thrombolysis (data collected from October 2017 – September 2018), PPCI patients have a shorter median hospital length of stay (4 days vs 6 days), and higher proportion of early discharge within 4 days (53.5% vs 14.1%). This study reflects the real world practice of a large cohort of non-selected patients presented with suspected STEMI, and shows that cluster-based 24-hour PPCI service is feasible with outcome consistent with international standards. The “STEMI Call” system allows conjoint assessment by cardiologists and AED physicians, enables making correct diagnoses and reducing inappropriate use of thrombolysis or angiograms in ambiguous cases. The DTB time is reasonable for cases of secondary diversion given the inherent system delay. There were substantial proportion of critically ill patients presented with CS and cardiac arrest, and the in-hospital mortality of CS patients was actually in line with major international studies. On the other hand, both CS and non-CS patients surviving the index PPCI procedures have excellent outcome at 30-days. Future directions include streamlining the workflow to reduce system delay, implementing pre-hospital ECG in ambulance for primary diversion to PPCI center, training in management of cardiogenic shock and introducing advanced mechanical circulatory support devices, so that the outcome of STEMI patients could be improved further.
