Objectives This study sought to evaluate the prognostic usefulness of visual and quantitative perfusion cardiac magnetic resonance (CMR) ischemic burden in an unselected group of patients and to assess the validity of consensus-based ischemic burden thresholds extrapolated from nuclear studies.

Background There are limited data on the prognostic value of assessing myocardial ischemic burden by CMR, and there are none using quantitative perfusion analysis.

Methods Patients with suspected coronary artery disease referred for adenosine-stress perfusion CMR were included (n = 395; 70% male; age 58 ± 13 years). The primary endpoint was a composite of cardiovascular death, nonfatal myocardial infarction, aborted sudden death, and revascularization after 90 days. Perfusion scans were assessed visually and with quantitative analysis. Cross-validated Cox regression analysis and net reclassification improvement were used to assess the incremental prognostic value of visual or quantitative perfusion analysis over a baseline clinical model, initially as continuous covariates, then using accepted thresholds of ≥2 segments or ≥10% myocardium.

Results After a median 460 days (interquartile range: 190 to 869 days) follow-up, 52 patients reached the primary endpoint. At 2 years, the addition of ischemic burden was found to increase prognostic value over a baseline model of age, sex, and late gadolinium enhancement (baseline model area under the curve [AUC]: 0.75; visual AUC: 0.84; quantitative AUC: 0.85). Dichotomized quantitative ischemic burden performed better than visual assessment (net reclassification improvement 0.043 vs. 0.003 against baseline model).

Conclusions This study was the first to address the prognostic benefit of quantitative analysis of perfusion CMR and to support the use of consensus-based ischemic burden thresholds by perfusion CMR for prognostic evaluation of patients with suspected coronary artery disease. Quantitative analysis provided incremental prognostic value to visual assessment and established risk factors, potentially representing an important step forward in the translation of quantitative CMR perfusion analysis to the clinical setting.

目的本研究旨在评估视觉和定量灌注心脏磁共振（CMR）缺血负荷对未选患者的预后价值，并评估从核研究推断出的基于共识的缺血负荷阈值的有效性。

背景：关于通过CMR评估心肌缺血负荷的预后价值的数据有限，并且没有使用定量灌注分析的数据。

方法纳入怀疑为腺苷应激灌注CMR的可疑冠状动脉疾病患者（n = 395；男性占70％；年龄58±13岁）。主要终点指标是心血管死亡，非致命性心肌梗塞，流产猝死和90天后血运重建的综合结果。目视和定量分析评估灌注扫描。交叉验证的Cox回归分析和净重分类改善用于评估基线临床模型上视觉或定量灌注分析的递增预后价值，最初是连续协变量，然后使用≥2个区段或≥10％心肌的公认阈值。

结果在进行了460天（四分位间距：190至869天）的中位随访之后，有52例患者达到了主要终点。在2年时，发现增加缺血负荷可提高年龄，性别和late晚期增强的基线模型的预后价值（曲线下的基线模型面积[AUC]：0.75；视觉AUC：0.84；定量AUC：0.85 ）。二等分的定量缺血负荷表现优于视觉评估（相对于基线模型，净重分类改善为0.043对0.003）。

结论本研究是第一个研究定量分析灌注CMR的预后益处，并支持通过灌注CMR将基于共识的局部缺血负荷阈值用于可疑冠心病患者的预后评估。定量分析为视觉评估和确定的危险因素提供了增加的预后价值，可能代表着将定量CMR灌注分析转化为临床环境的重要一步。