Cardiogenic shock in the Aachen Digital Myocardial Infarction Registry

Introduction

Guideline-oriented therapy of acute coronary syndrome (ACS) with ST-elevation myocardial infarction (STEMI) calls for quick and early treatment. The creation of an infarct network has been associated with streamlined treatment and a reduction of hospital mortality. Whether patients with cardiogenic shock (CS) receive similar, optimized treatment as regular STEMI patients is unclear.

Methods

We created the Aachen Digital Myocardial Infarction Registry (ADMIRE) database according to the European Cardiology Audit and Registration Data standards for clinical cardiology practice. Patients were labelled according to the presenting form of ACS. The infarct network included local ambulance services (LA), local hospitals (LH) and the interventional center with an emergency department (ED) and a 24/7 cath lab crew. To improve performance we introduced prehospital triage, fax-transmission of ECG, and direct alert of the cath lab crew by telephone. We determined treatment variables, median index-to-door (IDT) and door-to-sheath (DST) times and hospital mortality.

Results

Between April and December 2006 we treated 593 patients including 119 STEMI (20.1%) and 45 CS patients (7.6%); 66.7% were male, mean age was 67.4 years. CS presented with ST elevation in 48.9%, as non-STEMI in 33.3%, rescue percutaneous coronary intervention (PCI) in 11.1% or with subacute ACS in 6.7%; 30.4% of CS were admitted through LA, 67.4% through LH and only one patient through the ED. Upon admission, 50% of CS had required CPR, 69.6% were on mechanical ventilation. In total 89.1% of CS underwent angiography, with revascularization in 69.8% and intra-aortal balloon pump treatment in 68.1%. The median DST for CS vs STEMI was 82 vs 59.5 minutes (P = 0.07), and the IDT was shorter for CS (172 vs 385 min, P < 0.05). Stratified by admission source, the DST was equal between LA and LH (66 vs 84 min, P = 0.75). CS patients with ST elevation were not treated significantly faster than those without or CS with rescue PCI (64 vs 84 vs 94 min, P > 0.05 for each). Prehospital CPR did not lead to significantly altered DST. The DST was <60 minutes in 31.3% of CS compared with 50% STEMI patients. Mortality in CS patients was significantly higher than that of STEMI patients (56.5% vs 7.6%, P < 0.05) but equal among CS subgroups (50% for ST-elevation CS, 80% for non-STEMI CS, 40% for rPCI CS, no deaths for CS with subacute ACS). It did not differ by admission source and was not influenced by a DST < 60 minutes, intra-aortal balloon pump or revascularization status.

Conclusion

Despite their higher complexity, patients with CS were treated as fast as patients with STEMI, yet there was room for improvement to increase the number of patients treated within the first hour of admission for both STEMI and CS. Structural changes and further implementation of standard operating procedures might achieve this. We could not show a mortality difference for any of our treatment variables, which might be due to the low number of patients.