Background: Type 2 myocardial infarction and myocardial injury are common in clinical practice, but long-term consequences are uncertain. We aimed to define long-term outcomes and explore risk stratification in patients with type 2 myocardial infarction and myocardial injury.

Methods: We identified consecutive patients (n=2122) with elevated cardiac troponin I concentrations (≥0.05 µg/L) at a tertiary cardiac center. All diagnoses were adjudicated as per the universal definition of myocardial infarction. The primary outcome was all-cause death. Secondary outcomes included major adverse cardiovascular events (eg, nonfatal myocardial infarction or cardiovascular death) and noncardiovascular death. To explore competing risks, cause-specific hazard ratios were obtained using Cox regression models.

Results: The adjudicated index diagnosis was type 1 or 2 myocardial infarction or myocardial injury in 1171 (55.2%), 429 (20.2%), and 522 (24.6%) patients, respectively. At 5 years, all-cause death rates were higher in those with type 2 myocardial infarction (62.5%) or myocardial injury (72.4%) compared with type 1 myocardial infarction (36.7%). The majority of excess deaths in those with type 2 myocardial infarction or myocardial injury were because of noncardiovascular causes (hazard ratio, 2.32; 95% confidence interval, 1.92–2.81 versus type 1 myocardial infarction). Despite this finding, the observed crude major adverse cardiovascular event rates were similar between groups (30.6% versus 32.6%), with differences apparent after adjustment for covariates (hazard ratio, 0.82; 95% confidence interval, 0.69–0.96). Coronary heart disease was an independent predictor of major adverse cardiovascular events in those with type 2 myocardial infarction or myocardial injury (hazard ratio, 1.71; 95% confidence interval, 1.31–2.24).

Conclusions: Despite an excess in noncardiovascular death, patients with type 2 myocardial infarction or myocardial injury have a similar crude rate of major adverse cardiovascular events as those with type 1 myocardial infarction. Identifying underlying coronary heart disease in this vulnerable population may help target therapies that could modify future risk.

背景： 2型心肌梗死和心肌损伤在临床实践中很常见，但长期后果尚不确定。我们的目的是确定 2 型心肌梗死和心肌损伤患者的长期结局并探索风险分层。

方法：我们在三级心脏中心连续确定了心肌肌钙蛋白 I 浓度升高（≥0.05 µg/L）的患者 (n=2122)。所有诊断均根据心肌梗塞的通用定义进行判定。主要结局是全因死亡。次要结局包括主要不良心血管事件（例如非致命性心肌梗死或心血管死亡）和非心血管死亡。为了探索竞争风险，使用 Cox 回归模型获得了特定原因的风险比。

结果：判定指标诊断为1型或2型心肌梗死或心肌损伤的患者分别为1171例（55.2%）、429例（20.2%）和522例（24.6%）。5 年时，2 型心肌梗死 (62.5%) 或心肌损伤 (72.4%) 患者的全因死亡率高于 1 型心肌梗死 (36.7%)。2 型心肌梗死或心肌损伤患者的超额死亡大多数是由于非心血管原因所致（与 1 型心肌梗死相比，风险比为 2.32；95% 置信区间为 1.92–2.81）。尽管有这一发现，观察到的粗主要不良心血管事件发生率在各组之间相似（30.6% 对比 32.6%），调整协变量后差异明显（风险比，0.82；95% 置信区间，0.69-0.96）。冠心病是 2 型心肌梗塞或心肌损伤患者主要不良心血管事件的独立预测因素（风险比，1.71；95% 置信区间，1.31-2.24）。

结论：尽管非心血管死亡过多，但 2 型心肌梗死或心肌损伤患者的主要不良心血管事件粗发生率与 1 型心肌梗死患者相似。识别这一弱势群体潜在的冠心病可能有助于针对可能改变未来风险的治疗方法。