Characteristics and long-term outcomes of patients with reduced ejection fraction referred for adenosine stress perfusion cardiac magnetic resonance imaging

Funding Acknowledgements Type of funding sources: None. Background Adenosine stress perfusion has been shown to be of minimal incremental benefit in distinguishing between ischaemic and non-ischaemic aetiology of severe left ventricular systolic dysfunction (LVSD) over and above that obtained from Cardiac Magnetic Resonance (CMR) with Late Gadolinium Enhancement (LGE). Stress CMR has, however, been shown to be effective in risk-stratifying LVSD patients, with ischaemia being an independent predictor of cardiovascular death or myocardial infarction (MI) and associated with higher rates of further intervention. Purpose Evaluate real world data from a single tertiary UK cardiac MRI centre to determine the characteristics and long-term clinical outcomes of patients with LVSD referred for stress CMR. Methods As part of an ongoing registry, all consenting patients with Ejection Fraction (EF) ≤40% and a completed adenosine stress perfusion CMR between January 2015 and December 2019 were included with prospective baseline data collection. All-cause mortality and cardiac hospitalisation, coronary angiography/revascularisation was determined from electronic hospital records. Outcomes were compared between the inducible ischaemia vs. no ischaemia groups, and LGE present vs. no LGE groups using chi square. Results The sample included 86 patients. The mean EF was 32 ± 6%. Median follow up was 3.8 years (range 41-2222 days). The indications for CMR were: 30 (35%) assess ischaemia, 35 (41%) assess LVSD aetiology and 21 (24%) LVSD assess viability. Inducible ischemia was present in 30 (35%) patients and absent in 56 (65%). Patient characteristics and outcomes are shown in Table 1. Baseline characteristics were similar between the groups but there was a higher rate of hypertension and ischaemic heart disease in the ischaemia group. There was a non-significant difference in combined mortality and cardiac hospitalisation rates between the groups (40% vs. 27% p = 0.20). LGE was present in 69 (80%) patients (28 with ischaemia; 41 without) and absent in 17 (20%, 2 with ischaemia, 15 without). The event rate was 23 (33%) vs. 4 (24%) between LGE vs. No LGE groups (p = 0.44). Of the 15 patients (17%) with no LGE or ischaemia; 2 died and 1 was hospitalised, there were no MI"s and no Percutaneous Coronary Intervention (PCI). The lack of statistical difference in event rates between ischaemia and no ischaemia groups may be due to our relatively small sample size or could reflect the effectiveness of contemporary disease modifying treatment for Heart Failure with reduced EF. Conclusion This real-world data supports published findings that in patients with LVSD and no LGE on CMR, ischaemia is very uncommon and stress CMR is unlikely to increase diagnostic yield. Conversely, if stress CMR is performed and ischaemia is absent, incidence of subsequent angiography and revascularisation is very low, which is reassuring in clinical practice. In those patients without ischaemia and LGE, likelihood of MI is low.

P875Myocardial perfusion reserve assessment in patients with angina pectoris and suspected coronary spasm

Background Patients with signs and symptoms of myocardial ischemia yet unobstructed coronary arteries represent a diagnostic and therapeutic challenge. Coronary vasomotor disorders such as coronary epicardial or microvascular spasm are frequently found among these patients. They can be diagnosed using intracoronary acetylcholine testing (ACH-test). It has been shown that patients with epicardial spasm have a worse prognosis compared to patients with microvascular spasm. The reasons for this finding are however not apparent. We speculated in this study that patients with epicardial spasm have a worse vasomotor dysfunction compared to patients with microvascular spasm or normal ACH-test. To assess this hypothesis all patients in this study not only underwent ACH-testing but in addition also adenosine stress perfusion cardiac MRI (CMR) with calculation of the myocardial perfusion reserve index (MPRI). The latter method allows for assessment of vasodilatory function compared to the vasoconstrictor assessment using acetylcholine. Methods Between 2012 and 2016, 129 consecutive patients (mean age 64±13 years, 46% female) with signs and symptoms of myocardial ischemia yet unobstructed coronary arteries were enrolled in this study. All patients underwent ACH-testing as well as adenosine stress perfusion CMR. According to the results of the acetylcholine test, patients were allocated to 3 groups: a) epicardial spasm (angina, ischemic ECG changes and >75% coronary diameter reduction), b) microvascular spasm (angina, ischemic ECG changes and <75% coronary diameter reduction) and c) no evidence of coronary artery spasm. CMR-derived MPRI was calculated semiquantitatively from myocardial signal intensity-over-time curves of adenosine stress and rest perfusion. Results Epicardial and microvascular spasm was found in 31 (24%) and 69 (53%) patients, respectively, while 29 (22%) patients had no evidence of coronary spasm on ACH-testing. Women were more likely to have microvascular spasm than men (68% vs. 36%, p<0.001). The prevalence of epicardial spasm did not significantly differ between female and male patients (18% vs. 31%, p=0.08). MPRI was similar in patients with microvascular spasm compared to patients without spasm (1.30 vs. 1.27, p=0.43). However, patients with epicardial spasm had significantly lower MPRI than patients without spasm (1.16 vs. 1.30, p<0.05) or those with microvascular spasm (1.16 vs. 1.27, p<0.05). Conclusion MPRI determined by stress perfusion CMR was significantly reduced in patients with epicardial spasm compared to those with microvascular spasm or normal ACH-test. This could indicate that patients with epicardial spasm have a more generalized coronary vasomotor disorder compared to other patients. This may be the reason for the worse outcome observed and could lead to more aggressive medical therapy and closer follow-up. Acknowledgement/Funding This work was funded by the Robert-Bosch-Stiftung, Stuttgart, Germany and the Berthold-Leibinger-Stiftung, Ditzingen, Germany.

Combined single-session cardiovascular magnetic resonance: stress perfusion and three-dimensional pulmonary vein angiography for stratification of atrial fibrillation patients with chest pain syndromes prior to catheter ablation

Aims To determine the clinical utility of a combined single-session cardiovascular magnetic resonance (CMR) imaging protocol integrating adenosine stress perfusion and three-dimensional pulmonary vein angiography for stratification of atrial fibrillation (AF) patients referred for pulmonary vein isolation (PVI) and complaining about chest pain syndromes. Methods and results The preprocedural CMR examination (adenosine stress perfusion, late gadolinium enhancement, and three-dimensional pulmonary vein angiography) was performed in 357 consecutive AF patients with chest pain syndromes referred for PVI. Stress perfusion results were used for stratification: ischaemia positive patients underwent invasive coronary angiography, ischaemia negative patients underwent PVI, and follow-up/outcome data were collected (combined primary endpoint of cardiac death/non-fatal myocardial infarction). The integrated CMR protocol had a high success rate (356/357, 99.7%), a short total examination duration (<30 min in all patients), and delivered high-quality three-dimensional pulmonary vein angiography in all patients undergoing PVI (324/324, 100%). Variants of pulmonary vein anatomy were identified in 33% of all patients (117/357). Stress positivity (28/356, 8%) had a high positive predictive value for identification of obstructive coronary artery disease (86%), while stress negativity carried a low short-term event rate following PVI (cumulative 1-year event-free survival rate, 99.6%). Conclusion Combined single-session CMR as a routine diagnostic workup for AF patients with chest pain syndromes prior to PVI proved to represent a time-efficient and effective stratification tool.