Antithrombotic therapies in Canadian atrial fibrillation patients with concomitant coronary artery disease: Insights from the CONNECT AF + PCI-II program.

BACKGROUND: Selecting the appropriate antithrombotic regimen for patients with atrial fibrillation (AF) who have undergone percutaneous coronary intervention (PCI) or have had medically managed acute coronary syndrome (ACS) remains complex. This multi-centre observational study evaluated patterns of antithrombotic therapies utilized among Canadian patients with AF post-PCI or ACS. METHODS AND RESULTS: By retrospective chart audit, 611 non-valvular AF patients [median (interquartile range) age 76 (69-83) years, CHADS2 score 2 (1-3)] who underwent PCI or had medically managed ACS between August 2018 and December 2020 were identified by 68 cardiologists across eight provinces in Canada. Overall, triple antithrombotic therapy [TAT: combined oral anticoagulation (OAC) and dual antiplatelet therapy (DAPT)] was the most common initial antithrombotic strategy, with use in 53.8 % of patients, followed by dual pathway therapy (32.7 % received OAC and a P2Y12 inhibitor, and 4.1 % received OAC and aspirin) and DAPT (9.3 %). Median duration of TAT was 30 (7, 30) days. Compared to the previous CONNECT AF + PCI-I program, there was an increased use of dual pathway therapy relative to TAT over time (P-value <.0001). DOACs (direct oral anticoagulants) represented 90.3 % of all OACs used overall, with apixaban being the most utilized (50.5 %). Proton pump inhibitors were used in 57.0 % of all patients, and 70.1 % of patients on ASA. Planned antithrombotic therapies at 1 year were: 76.2 % OAC monotherapy, 8.3 % OAC + ASA, 7.9 % OAC + P2Y12 inhibitor, 4.3 % DAPT, 1.3 % ASA alone, and <1 % triple therapy. CONCLUSION: In accordance with recent Canadian Cardiovascular Society guideline recommendations, we observed an increased use of dual pathway therapy relative to TAT over time in both AF patients post-PCI (elective and emergent) and in those with medically managed ACS. Additionally, DOACs have become the prevailing form of anticoagulation across all antithrombotic regimens. Our findings suggest that Canadian physicians are integrating evidence-based approaches to optimally manage the bleeding and thrombotic risks of AF patients post-PCI and/or ACS.

Prognostic value of SPECT myocardial perfusion imaging in patients with elevated cardiac troponin I levels and atypical clinical presentation.

BACKGROUND: We determined the prognostic value of myocardial perfusion imaging (MPI) in patients with atypical clinical presentations and unexpected elevation of cardiac troponin I (cTnI) levels. METHODS AND RESULTS: In 156 consecutive patients with atypical presentations for acute coronary syndromes (ACS) and elevated cTnI levels undergoing MPI within 30 days, rates of all-cause mortality (100% follow-up; median follow-up, 611 days) and 6-month cardiac death and nonfatal myocardial infarction (96% follow-up; median follow-up, 167 days) were determined. The mean age of the patients was 68 +/- 14 years. The majority of the study cohort (96%) was at low to intermediate clinical risk for ACS (Thrombolysis in Myocardial Infarction score for unstable angina/non-ST-segment elevation myocardial infarction <5). The overall event rate was high, with 45 deaths (28.8%). There were 13 cardiac deaths/nonfatal myocardial infarctions in 6 months (8.3%). A normal MPI result was associated with a high event-free survival rate, whereas an abnormal MPI result was associated with a 3-fold and 7-fold higher risk of all-cause mortality and 6-month cardiac events, respectively. An abnormal MPI result was an independent predictor of all-cause death. CONCLUSIONS: In patients with cTnI elevation and a low to intermediate risk for ACS, a normal MPI result portends a good prognosis. Patients with abnormal MPI results have a higher 6-month cardiac event rate and a worse survival rate.

Quantitative relation between hemodynamic changes during intravenous adenosine infusion and the magnitude of coronary hyperemia: implications for myocardial perfusion imaging.

OBJECTIVES: The goal of this study was to determine the relationship between changes in cardiac hemodynamics during intravenous adenosine (ADO) infusion, and myocardial blood flow (MBF). BACKGROUND: The relationship between changes in MBF and the peripheral hemodynamic effects during peak adenosine infusion is unknown. METHODS: We studied 348 (age 57 +/- 11 years; 106 females) without evidence of obstructive coronary artery disease by positron emission tomography (PET). Patients underwent [(13)N]ammonia PET imaging to measure MBF and coronary vascular resistance (CVR) at rest and during a standard 6-min ADO infusion. Changes in heart rate (HR) and mean arterial pressure (MAP) were measured at baseline and during peak hyperemia. RESULTS: During ADO, HR increased (delta: 24 +/- 11 beats/min) and MAP decreased (delta: -2 +/- 10 mm Hg). Overall, delta HR correlated poorly with hyperemic MBF (R = 0.10, p = 0.06) and with CVR (R = 0.11, p = 0.04). Delta MAP also showed a weak correlation with hyperemic MBF (R = 0.04, p = 0.44) and with CVR (R = 0.11, p = 0.04). Patients in the lowest tertile for delta HR showed a 7% lower hyperemic MBF (1.84 +/- 0.6 ml/min/g vs. 1.98 +/- 0.6 ml/min/g, p = 0.022) and an 8% higher CVR (54 +/- 20 mm Hg/ml/min/g vs. 50 +/- 17 mm Hg/ml/min/g, p = 0.056) compared with those in the highest tertile. Patients in the lowest tertile for delta MAP (i.e., greatest decline) showed similar hyperemic MBF, and an 8% lower CVR compared with those in the highest tertile (p = NS for both). These small differences between tertiles remain, even after adjusting for differences in age, gender, smoking status, and lipid profile. CONCLUSIONS: Changes in cardiac hemodynamics during intravenous ADO are generally poor predictors of changes in MBF and CVR during peak hyperemia, and, thus, they should not be used to assess the effectiveness of vasodilator stress in myocardial perfusion imaging.

Paradoxical changes in brain natriuretic peptide levels and loading conditions after intravenous conscious sedation.

BACKGROUND: Elevated filling pressure and wall stress have been proposed as stimuli for elevated brain natriuretic peptide (BNP) levels. Narcotic and benzodiazepine sedation, such as is used for transesophageal echocardiography (TEE), is known to decrease filling pressures. We hypothesized that lower filling pressure and wall stress associated with intravenous conscious sedation (IVCS) would lead to lower BNP levels. METHODS: We studied BNP levels, blood pressure, and echocardiographic indices of filling pressure and wall stress before and after IVCS and TEE. RESULTS: When data before and after IVCS and TEE were compared, mean blood pressure decreased (149 +/- 24/83 +/- 14 mm Hg vs 126 +/- 29/69 +/- 14; P < .01), as did mitral Doppler E wave velocity (82 +/- 23 cm/s vs 76 +/- 22; P < .05), right ventricular/atrial gradient (31 +/- 10 mm Hg vs 29 +/- 13; P < .05), and wall stress. However, BNP levels increased (195 +/- 407 pg/mL vs 238 +/- 458; P < .01). CONCLUSIONS: In a series of patients undergoing clinically indicated TEE, BNP levels increase above baseline after IVCS. The increase in BNP occurs despite lower blood pressure, lower mitral Doppler E velocity, lower right ventricular/atrial gradient, and lower wall stress compared with baseline. The mechanism of the paradoxical increase in BNP is not entirely clear, but it may conceivably be a result of counterregulatory hormone release caused by acute decrease in blood pressure.

Brain natriuretic peptide levels fall rapidly after cardioversion of atrial fibrillation to sinus rhythm.

BACKGROUND: Brain natriuretic peptide (BNP) levels have been reported to fall following cardioversion of atrial fibrillation (AF). The mechanism for the fall in BNP has not been elucidated and the potential confounding effects of sedation have not been investigated. Sedation may alter BNP levels via its effects on loading conditions. Accordingly, we studied whether BNP levels change shortly after cardioversion and attempted to control for possible effects of sedation. METHODS: BNP levels were obtained before and after cardioversion in patients with AF and in a control group of patients undergoing intravenous conscious sedation for transesophageal echocardiography. RESULTS: BNP levels dropped (260 +/- 255 vs. 190 +/- 212 pg/ml, p < 0.05) 40 min after cardioversion, decreasing in 33 of 41 subjects who achieved sinus rhythm. By contrast, mean BNP did not fall in subjects in whom cardioversion was not successful. The change in BNP level was not related to the degree of change in heart rate. No control subject experienced a change in cardiac rhythm; BNP levels increased (195 +/- 407 vs. 238 +/- 458 pg/ml, p < 0.05) in 18/22 subjects after sedation. Baseline BNP levels were elevated in subjects with AF, and BNP levels were elevated in parallel with heart failure symptoms. CONCLUSIONS: The rapid fall in BNP after cardioversion (1) may reflect prompt hemodynamic improvement associated with rhythm change and (2) does not appear to be due to the effects of sedation.