Coronary flow reserve in hypertrophic cardiomyopathy: relation with microvascular dysfunction and pathophysiological...

Area of Science:

• Cardiology
• Cardiovascular Physiology

Background:

• Coronary flow reserve (CFR) reduction in hypertrophic cardiomyopathy (HCM) is linked to myocardial ischemia, systolic dysfunction, and cardiac death.
• Understanding the factors contributing to CFR reduction in HCM is crucial for patient management.

Purpose of the Study:

• To investigate the contribution of hemodynamic, echocardiographic, and histological parameters to the reduction of CFR in patients with HCM.
• To identify specific echocardiographic and hemodynamic markers associated with decreased CFR in HCM.

Main Methods:

• Assessed CFR in the left anterior descending coronary artery of 10 HCM patients and 8 heart transplant (HTX) patients.
• Evaluated hemodynamic, echocardiographic, and histological parameters in all subjects.
• Utilized linear regression analysis to determine the relationship between variables and CFR.

Main Results:

• CFR was significantly lower in HCM patients (1.6±0.7) compared to HTX patients (2.7±0.8).
• Increased septal thickness, indexed left ventricular (LV) mass, LV end-diastolic pressure, and LV outflow tract gradient were associated with reduced CFR.
• A decrease in arteriolar lumen size also correlated with reduced CFR.

Conclusions:

• Hemodynamic factors (LV end-diastolic pressure, LV outflow tract gradient), echocardiographic findings (indexed LV mass), and histological changes (arteriolar lumen size) collectively contribute to CFR reduction in HCM.
• These findings highlight the multifactorial nature of impaired coronary blood flow in HCM.