Microvascular function and inflammatory activation in Takotsubo cardiomyopathy.

Area of Science:

• Cardiology
• Immunology
• Pathophysiology

Background:

• Takotsubo syndrome (TTS) is an acute cardiac condition with unclear pathophysiology.
• Microvascular dysfunction and inflammation are suspected contributors to TTS.

Purpose of the Study:

• To assess microvascular function in the acute phase of TTS.
• To identify inflammatory mediators associated with TTS-induced pathology.

Main Methods:

• Evaluated 20 female TTS patients using cardiac catheterization to measure index of microvascular resistance (IMR) and collected blood samples from aorta and coronary sinus.
• Performed cardiac magnetic resonance imaging (MRI) in the acute phase.
• Compared inflammatory biomarkers with healthy controls and analyzed changes over 3 months.

Main Results:

• Median IMR was slightly elevated (16.5 mmHg·s), but 35% of patients exhibited IMR > 25 mmHg·s, indicating microvascular dysfunction.
• Cardiac MRI showed apical left ventricular involvement in 65% of patients, with a median ejection fraction of 41%.
• Elevated markers of fibrosis, inflammation, and immune activation were observed compared to controls; only IL-1 receptor antagonist and sTIM-3 were higher in the coronary sinus than aorta. Matrix metalloproteinase-9 increased during follow-up.

Conclusions:

• While median IMR was only slightly elevated, a significant proportion of TTS patients display microvascular dysfunction.
• The study supports the involvement of inflammatory pathways, including monocyte/macrophage activation, in TTS.
• Soluble T-cell immunoglobulin mucin domain-3 (sTIM-3) is identified as a potential novel biomarker for TTS.