Key result
Takotsubo syndrome is linked to an elevated median LAD caIMR of ~40 versus controls.
Why the study?
Coronary microvascular dysfunction has been proposed as crucial in Takotsubo syndrome pathophysiology, but its prevalence, transience, and clinical impact using caIMR remained to be evaluated.
Does coronary angiography-derived index of microcirculatory resistance (caIMR) correlate with in-hospital outcomes and differ from controls in patients with Takotsubo syndrome?
Observational (n=192)
Single-blind
No
Does coronary angiography-derived index of microcirculatory resistance (caIMR) correlate with in-hospital outcomes and differ from controls in patients with Takotsubo syndrome?
Absolute Event Rate: 39.9% vs 19.8%
p-value: p=<0.001
Coronary microvascular dysfunction is transiently present in all three major coronary arteries during acute Takotsubo syndrome, and its severity correlates with adverse in-hospital clinical outcomes.
CMD via caIMR is prevalent, transient, and associated with in-hospital MACE in TTS; leaves open whether assessment aids risk stratification.
BACKGROUND: Coronary microvascular dysfunction (CMD) has been proposed as a crucial factor in the pathophysiology of Takotsubo syndrome (TTS). The angiography-derived index of microcirculatory resistance (caIMR) offers an alternative to conventional hyperemic wire-based IMR to assess CMD. We aimed to evaluate CMD's prevalence, transience, and impact on in-hospital outcomes in TTS. METHODS: All three coronary arteries of 96 patients with TTS were assessed for their coronary angiography derived Index of microcirculatory Resistance (caIMR) and compared to non-obstructed vessels of matched patients with ST-elevation myocardial infarction. Further, the association between caIMR and the TTS-specific combined in-hospital endpoint of death, cardiac arrest, ventricular arrhythmogenic events and cardiogenic shock was investigated. RESULTS: Elevated IMR was present in all TTS patients, with significantly elevated caIMR values in all coronary arteries compared to controls. CaIMR did not differ between apical and midventricular TTS types. CaIMR normalized in TTS patients with follow-up angiographies performed at a median of 28 months (median caIMR at event vs follow-up: LAD 34.8 [29.9-41.1] vs 20.3 [16.0-25.3], p < 0.001; LCX: 38.7 [32.9-50.1] vs 23.7 [19.4-30.5], p < 0.001; RCA: 31.7 [25.0-39.1] vs 19.6 [17.1-24.0], p < 0.001). The extent of caIMR elevation significantly correlated with the combined in-hospital endpoint (p = 0.036). CONCLUSION: TTS patients had evidence of elevated caIMR in at least one coronary artery with a trend towards higher LAD caIMR in apical type TTS and normalization after recovery. Furthermore, extent of caIMR elevation was associated with increased risk of in-hospital MACE of TTS patients.
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Schweiger et al. (2023) conducted an observational in Takotsubo syndrome (n=192). Takotsubo syndrome vs. Non-culprit vessels of matched patients with ST-elevation myocardial infarction was evaluated on Angiography-derived index of microcirculatory resistance (caIMR) in the left anterior descending artery (LAD) (p=<0.001). Takotsubo syndrome was associated with significantly elevated angiography-derived index of microcirculatory resistance in the LAD compared to controls (median 39.9 vs 19.8, p<0.001).
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