Paired risk scores to predict ischaemic and bleeding risk twenty-eight days to one year after an acute coronary syndrome.

OBJECTIVE: The recommended duration of dual anti-platelet therapy (DAPT) following acute coronary syndrome (ACS) varies from 1 month to 1 year depending on the balance of risks of ischaemia and major bleeding. We designed paired ischaemic and major bleeding risk scores to inform this decision. METHODS: New Zealand (NZ) patients with ACS investigated with coronary angiography are recorded in the All NZ ACS Quality Improvement registry and linked to national health datasets. Patients were aged 18-84 years (2012-2020), event free at 28 days postdischarge and without atrial fibrillation. Two 28-day to 1-year postdischarge multivariable risk prediction scores were developed: (1) cardiovascular mortality/rehospitalisation with myocardial infarction or ischaemic stroke (ischaemic score) and (2) bleeding mortality/rehospitalisation with bleeding (bleeding score). FINDINGS: In 27 755 patients, there were 1200 (4.3%) ischaemic and 548 (2.0%) major bleeding events. Both scores were well calibrated with moderate discrimination performance (Harrell's c-statistic 0.75 (95% CI, 0.74 to 0.77) and 0.69 (95% CI, 0.67 to 0 .71), respectively). Applying these scores to the 2020 European Society of Cardiology ACS antithrombotic treatment algorithm, the 31% of the cohort at elevated (>2%) bleeding and ischaemic risk would be considered for an abbreviated DAPT duration. For those at low bleeding risk, but elevated ischaemic risk (37% of the cohort), prolonged DAPT may be appropriate, and for those with low bleeding and ischaemic risk (29% of the cohort) short duration DAPT may be justified. CONCLUSION: We present a pair of ischaemic and bleeding risk scores specifically to assist clinicians and their patients in deciding on DAPT duration beyond the first month post-ACS.

Clinical trials of direct thrombin and factor Xa inhibitors in atrial fibrillation.

PURPOSE OF REVIEW: To review the large phase 3 clinical trials that compare direct thrombin or factor Xa inhibitors with dose-adjusted warfarin in patients with atrial fibrillation who have an increased risk of stroke. RECENT FINDINGS: In large clinical trials, the oral direct thrombin inhibitor ximelagatran and the long-acting factor Xa inhibitor idraparinux were effective for reducing the risk of thromboembolic stroke, but were not marketed because of liver toxicity and excessive bleeding, respectively. In separate clinical trials, the oral direct thrombin inhibitor dabigatran etexilate and the short-acting oral factor Xa inhibitor rivaroxaban were noninferior or superior to dose-adjusted warfarin for prevention of thromboembolic stroke and systemic embolism, without increasing the risk of bleeding, and were well tolerated. Apixaban, another oral factor Xa inhibitor, is effective in reducing thromboembolic stroke compared with aspirin alone. Results of a trial comparing apixaban with dose-adjusted warfarin are awaited. SUMMARY: Dabigatran and rivaroxaban are effective, safe alternatives to dose-adjusted warfarin for reducing thromboembolic risk in patients with atrial fibrillation at high risk of stroke.

The impact of a national COVID-19 lockdown on acute coronary syndrome hospitalisations in New Zealand (ANZACS-QI 55).

BACKGROUND: Countries with a high incidence of coronavirus 2019 (COVID-19) reported reduced hospitalisations for acute coronary syndromes (ACS) during the pandemic. This study describes the impact of a nationwide lockdown on ACS hospitalisations in New Zealand (NZ), a country with a low incidence of COVID-19. METHODS: All patients admitted to a NZ Hospital with ACS who underwent coronary angiography in the All NZ ACS Quality Improvement registry during the lockdown (23 March - 26 April 2020) were compared with equivalent weeks in 2015-2019. Ambulance attendances and regional community troponin-I testing were compared for lockdown and non-lockdown (1 July 2019 to 16 February 2020) periods. FINDINGS: Hospitalisation for ACS was lower during the 5-week lockdown (105 vs. 146 per-week, rate ratio 0•72 [95% CI 0•61-0•83], p = 0.003). This was explained by fewer admissions for non-ST-segment elevation ACS (NSTE-ACS; p = 0•002) but not ST-segment elevation myocardial infarction (STEMI; p = 0•31). Patient characteristics and in-hospital mortality were similar. For STEMI, door-to-balloon times were similar (70 vs. 72 min, p = 0•52). For NSTE-ACS, there was an increase in percutaneous revascularisation (59% vs. 49%, p<0•001) and reduction in surgical revascularisation (9% vs. 15%, p = 0•005). There were fewer ambulance attendances for cardiac arrests (98 vs. 110 per-week, p = 0•04) but no difference for suspected ACS (408 vs. 420 per-week, p = 0•44). Community troponin testing was lower throughout the lockdown (182 vs. 394 per-week, p<0•001). INTERPRETATION: Despite the low incidence of COVID-19, there was a nationwide decrease in ACS hospitalisations during the lockdown. These findings have important implications for future pandemic planning. FUNDING: The ANZACS-QI registry receives funding from the New Zealand Ministry of Health.

Diagnosis of MI after CABG with high-sensitivity troponin T and new ECG or echocardiogram changes: relationship with mortality and validation of the universal definition of MI.

AIMS: Criteria for diagnosing myocardial infarction (MI) after coronary artery bypass grafting (CABG) are controversial. Uncertainties remain around the optimal threshold for biomarker elevation and the need for associated criteria. There are no studies of high-sensitivity troponin (hs-TnT) after CABG. We assessed whether using hs-TnT to define MI after CABG was associated with 30-day and medium-term mortality and evaluated the utility of adding to the troponin criteria new Q-waves or imaging evidence of new wall motion abnormality as suggested in the Universal Definition of MI. METHODS: Isolated CABG was performed in 818 patients from July 2010 to June 2012 and hs-TnT was measured 12-24 hours after CABG. Patients with rising baseline or missing troponins (n=258) were excluded. Thresholds of 140 ng/l (10-times 99th percentile upper reference limit) and 500 ng/l (10-times coefficient of variation of 10% for fourth-generation troponin T applied to hs-TnT) were prespecified. RESULTS: Mean follow up was 1.8±0.6 years. On multivariate analyses, isolated hs-TnT rise >140 ng/l (n=360) or >500 ng/l (n=162) were not associated with mortality. Additional ECG and/or echocardiographic criteria plus hs-TnT >140 ng/l was associated with 30-day mortality (hazard ratio, HR, 4.92, 95% CI 1.34-18.1; p=0.017) and medium-term mortality (HR 3.44, 95% CI 1.13-10.5; p=0.030), whereas ECG and/or echocardiographic abnormalities with hs-TnT >500 ng/l was not (p=0.281 and p=0.123 for 30-day and medium-term mortality, respectively). CONCLUSIONS: A definition for MI following CABG using hs-TnT with a cut point of 10-times 99th percentile upper reference limit and ECG and/or echocardiographic criteria predicts 30-day and medium-term mortality. These findings validate the Third Universal Definition of type 5 MI.

Novel methods to assess heart valve disease.

Optimal timing of surgery for heart valve disease relies on the accurate assessment of symptoms, lesion severity, cardiac function and the risks of disease progression. Recent studies suggest potential roles for new echocardiographic techniques, including tissue Doppler and strain imaging at rest or after exercise stress, cardiac magnetic resonance imaging and biomarkers such as B-type natriuretic peptide. These techniques may identify patients at higher risk of symptomatic deterioration or adverse clinical events, and improve the cost-effectiveness and reliability of follow-up.