FUNCTIONAL ASSESSMENT OF MICROCIRCULATION IN TAKOTSUBO CARDIOMYOPATHY – A PILOT STUDY

Background: Takotsubo cardiomyopathy (TTC) is a severe disorder with an increasing incidence that often mimics acute coronary syndrome. Both of the entities are characterized by systolic dysfunction of the left ventricle myocardium. However, this dysfunction is reversible in most cases of TTC. The pathophysiology of TTC remains unclear. In this study, we aimed to assess the pathophysiology of TTC using the invasive functional testing of coronary microcirculation.

Methods: Ten female patients diagnosed with TTC were included in this pilot study. In all subjects we measured fractional and coronary flow reserve in the left anterior descending and left circumflex coronary arteries, and the index of microcirculatory resistance in the same arteries in addition to acute and late transthoracic echocardiography (TTE). The results of the microcirculatory assessment were statistically compared with normal population values.

Results: Whilst fractional flow reserve was normal in both assessed epicardial artery territories for all patients, both mean values of coronary flow reserve disclosed pathological microcirculatory findings and were pathological in nine out of ten subjects. Index of microcirculatory resistance revealed abnormal values in five out of ten patients for LAD and three out of ten for LCx.

Conclusions: Our pilot study confirmed non-obstructive findings in the epicardial coronary arteries assessed by FFR. On the other hand, the investigation of both CFR and iMR, microcirculatory functional testing, revealed pathological findings in a significant number of evaluated subjects. From this aspect, our study validates further research in the field of microcirculatory functions as a possible mechanism in the origin of TTS. Our study will enroll 40 patients and is anticipated to complete enrollment by the end of 2022.