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Stress Perfusion CMR in Patients With Known and Suspected CAD: Prognostic Value and Optimal Ischemic Threshold for
Gabriella Vincenti1, Pier Giorgio Masci1, Pierre Monney1
1Division of Cardiology University Hospital of Lausanne (CHUV), Lausanne, Switzerland; Cardiac MR Center, University Hospital of Lausanne (CHUV), Lausanne, Switzerland.
Insights
Patients with coronary artery disease (CAD) and minimal ischemia (0-1 segment) on stress-perfusion cardiac magnetic resonance (CMR) can safely avoid revascularization. An ischemia burden of 1.5 segments or more strongly predicts adverse cardiac events.
Area of Science:
- Cardiovascular Imaging and Diagnostics
- Ischemic Heart Disease Management
- Cardiac Magnetic Resonance Imaging (CMR)
Background:
- Stress-perfusion CMR is vital for detecting myocardial ischemia in coronary artery disease (CAD).
- Evidence is lacking on the specific ischemia burden threshold for guiding revascularization decisions.
- Current guidelines need refinement regarding optimal patient selection for revascularization versus medical management.
Purpose of the Study:
- To establish the ischemia threshold predicting outcomes in patients with suspected or known CAD.
- To identify prognostic factors for safely deferring revascularization in a broad patient population.
- To evaluate the role of ischemia burden in risk stratification using stress-perfusion CMR.
Main Methods:
- Prospective enrollment of patients undergoing stress-perfusion CMR for ischemia assessment.
- CMR protocol included adenosine stress first-pass perfusion and late gadolinium enhancement (LGE).
- Ischemia and scar burden were quantified using 16- and 17-segment models, respectively.
Main Results:
- Ischemia burden (≥1.5 ischemic segments) was the strongest predictor of primary (cardiac death, MI, late revascularization) and secondary (cardiac death, MI) endpoints (HRs 7.42-8.72).
- Patients with no or <1.5 ischemic segments showed excellent outcomes, similar to those without ischemia.
- Age (≥67 years), reduced LVEF (≤40%), and scar burden (LGE score ≥0.03) were significant but lesser predictors.
Conclusions:
- An ischemia burden of ≥1.5 ischemic segments on stress-perfusion CMR is a key predictor of adverse cardiac events in CAD.
- Patients with 0 or 1 ischemic segment identified by CMR can be safely deferred from revascularization.
- Stress-perfusion CMR provides crucial prognostic information for guiding revascularization decisions in all-comer patients.
Objectives:
This study sought to determine the ischemia threshold and additional prognostic factors that identify patients for safe deferral from revascularizations in a large cohort of all-comer patients with known or suspected coronary artery disease (CAD).
Background:
Stress-perfusion cardiac magnetic resonance (CMR) is increasingly used in daily practice for ischemia detection. However, there is insufficient evidence about the ischemia burden that identifies patients who benefit from revascularization versus those with a good prognosis who receive drugs only.
Methods:
All patients with known or suspected CAD referred to stress-perfusion CMR for myocardial ischemia assessment were prospectively enrolled. The CMR examination included standard functional adenosine stress first-pass perfusion (gadobutrol 0.1 mmol/kg Gadovist, Bayer AG, Zurich, Switzerland) and late gadolinium enhancement (LGE) acquisitions. Presence of ischemia and ischemia burden (number of ischemic segments on a 16-segment model), and of scar and scar burden (number and transmurality of scar segments in a 17-segment model) were assessed. The primary endpoint was a composite of cardiac death, nonfatal myocardial infarction (MI), and late coronary revascularization (>90 days post-CMR); the secondary endpoint was a composite of cardiac death and nonfatal MI.
Results:
During a follow-up of 2.5 ± 1.0 years, 86 and 32 of 1,024 patients (1,103 screened patients) experienced the primary and secondary endpoints, respectively. On Kaplan-Meier curves for the primary and secondary endpoints, patients without ischemia had excellent outcomes that did not differ from patients with <1.5 ischemic segments. In multivariate Cox regression analyses of the entire population and of the subgroups, ischemia burden (threshold: ≥1.5 ischemic segments) was consistently the strongest predictor of the primary and secondary endpoints with hazard ratios (HRs) of 7.42 to 8.72 (p < 0.001), whereas age (≥67 years), left ventricular ejection fraction (≤40%), and scar burden (LGE score ≥0.03) contributed significantly, but to a lesser extent, in all models with HRs of 2.01 to 3.48, 1.75 to 1.96, and 1.66 to 1.76, respectively.
Conclusions:
In a large all-comer patient cohort with known and suspected CAD, an ischemia burden of ≥1.5 ischemic segments on stress-perfusion CMR was the strongest predictor of the primary and secondary endpoints. Patients with zero or 1 ischemic segment can be safely deferred from revascularizations.