Coronary microvascular dysfunction in patients with Takotsubo syndrome

The pathophysiology of Takotsubo syndrome (TTS) remains incompletely understood. While coronary microvascular dysfunction (CMD) is a potential pathophysiologic mechanism, evidence is limited.

We sought to evaluate CMD in patients with TTS.

Consecutive patients diagnosed with TTS were included and underwent coronary angiography with invasive microvascular function evaluation, including fractional flow reserve, Coronary Flow Reserve (CFR), Index of Microcirculatory Resistance (IMR), and Resistive Reserve Ratio (RRR). Patients had an echocardiography evaluation during their index admission and at approximately 6 weeks.

Thirty patients were included (mean age 74 ±9, 90 % female). Twenty-five patients (83 %) had at least one abnormal coronary microvascular function parameter. Abnormal parameters included CFR<2.5 in 20 patients (67 %), IMR>25 in 18 patients (60 %), and RRR<3.5 in 25 (83 %). Longer time from symptoms to angiography correlated with a higher CFR (r = 0.51, P<0.01), and had an area under the receiver operating characteristic curve of 0.793 (95 % CI 0.60-0.98) for pathologic CFR. Patients with emotional trigger had a lower rate of pathologic IMR compared with non-emotional trigger (36 % vs 81 %, p = 0.01). Follow up echocardiography performed at a median of 1.5 months (IQR 1.15-6) showed an improvement in left ventricular ejection fraction for all patients (from mean of 40 % to 57 %).

CMD was present in most patients with TTS. The role of microvascular function in TTS may vary according to the clinical presentation and RRR may be more sensitive for the diagnosis of CMD in TTS.