How common are non-acute coronary syndrome (ACS) diagnoses in patients with suspected ACS investigated with coronary angiography in New Zealand? (ANZACS-QI 58)

BACKGROUND AND AIMS

The last two decades in New Zealand have seen increased availability of primary percutaneous coronary intervention (PCI) for ST-segment elevation myocardial infarction (STEMI) and early invasive coronary angiography (ICA) for other high-risk acute coronary syndrome (ACS) patients. One metric to assess the clinical appropriateness of these invasive strategies is to examine the false-positive rate for the investigation (ie, the rate of non-ACS diagnoses).

METHODS

All patients presenting to New Zealand public hospitals with suspected ACS who underwent ICA between 2015 and 2019 were recorded prospectively in the All New Zealand Acute Coronary Syndrome Quality Improvement registry. The cohort was divided according to clinical impression at presentation: (1) suspected STEMI <24h and (2) other suspected ACS. The final discharge diagnosis for each patient were obtained from the registry.

RESULTS

There were 6,059 (20%) patients with suspected STEMI <24h and 24,258 (80%) with other suspected ACS. Of the suspected STEMIs <24h, 90.6% had a final diagnosis of STEMI, 3.5% non-ST segment elevation ACS (NSTEACS) and only 5.9% had a non-ACS diagnosis. Of those with other suspected ACS, 80.7% had a final ACS diagnosis. Across all New Zealand district health boards (DHBs), the proportion of non-ACS diagnoses was similar for suspected STEMI presentations. However, for other suspected ACS, the proportions were higher in DHBs with rapid access to coronary interventional facilities than in those without (17.6% vs 7.0%, p<0.001).

CONCLUSIONS

False-positive catheter laboratory activations for suspected STEMI patients are low across New Zealand. The differences in the proportion of non-ACS diagnoses according to DHB interventional capability for other suspected ACS requires further investigation.

Atrial fibrillation in acute coronary syndrome: patient characteristics and appropriate utilisation of anti-thrombotic therapy in New Zealand (ANZACS-QI 39)

BACKGROUND

Concomitant atrial fibrillation (AF) and acute coronary syndrome (ACS) present the difficult therapeutic dilemma of balancing bleeding, cardio-embolic and coronary thrombotic risks with appropriate combinations of antithrombotic medications. We aim to evaluate current New Zealand practice by identifying the incidence of AF in ACS; describe the population characteristics; and assess our antithrombotic management.

METHODS

Consecutive patients ≥18y presenting with ACS who had coronary angiography (2017-2018) were identified from the All New Zealand ACS Quality Improvement (ANZACS-QI) registry. The cohort was divided into three groups: 1) patients with pre-existing AF; 2) new-onset AF; and 3) no AF. Antithrombotic regimens included dual antiplatelet therapy (DAPT), dual antithrombotic therapy (DAT-single antiplatelet plus an oral anticoagulant (OAC)) and triple antithrombotic therapy (TAT).

RESULTS

There were 9,489 patients, 9.6% with pre-existing AF, 4.4% new AF and 86% without AF. Both AF groups were older (median 74 vs 71 vs 65y, p=0.001), had poorer renal function, were more likely to present with heart failure (16% vs 19% vs 8%, p=0.001) and have left ventricular ejection fraction <40% (22% vs 28% vs 13%, p<0.001). They received less percutaneous coronary intervention (PCI) (53% vs 59% vs 70%, p=0.001). In the cohort, 25 different combinations of antithrombotic agents were utilised. Ninety-six percent of patients with any AF had a CHA2DS2VASC stroke risk score of ≥2, of whom 48% did not receive OAC. Twenty-four percent received TAT and 19% DAT. OAC use increased slightly with increasing stroke risk but were independent of CRUSADE bleeding risk. Of patients with AF treated with PCI, 53% received DAPT, 11% DAT and 35% TAT. 51% of those at high stroke risk were discharged on DAPT only. In contrast, 19% at low stroke risk received TAT.

CONCLUSION

In New Zealand, one in seven patients presenting with ACS have AF, a third being new-onset AF. Antithrombotic management is inconsistent, with underutilisation of anticoagulants, particularly the DAT regimen, and is inadequately informed by stroke and bleeding risk scores.