Evaluation of Intravenous Versus Intracoronary Adenosine in Coronary Reactivity Testing

Area of Science:

• Cardiology
• Cardiovascular Physiology
• Medical Diagnostics

Background:

• Coronary flow reserve (CFR) and index of microcirculatory resistance (IMR) are crucial for diagnosing angina in non-obstructive coronary artery disease.
• Previous research established equivalence between intravenous (IV) and intracoronary (IC) adenosine for epicardial ischemia assessment via fractional flow reserve.
• The comparative efficacy of IC versus IV adenosine for achieving maximal hyperemia in coronary reactivity testing (CRT) remains unaddressed.

Purpose of the Study:

• To investigate the correlation between IC and IV adenosine administration during CRT.
• To evaluate if IC adenosine can serve as an alternative to IV adenosine in bolus thermodilution CRT.
• To compare CFR and IMR values derived from both IC and IV adenosine methods.

Main Methods:

• A retrospective analysis of CRT data and patient demographics was conducted.
• Maximal hyperemia was induced using both IC and IV adenosine in a cohort of patients.
• Statistical analyses included linear regression, ANOVA, Wilcoxon tests, and Bland-Altman analysis to compare CFR and IMR.

Main Results:

• Sixty-two patients (median age 60.5 years, 72% female) were analyzed.
• CFR values were 3.12 (IC) and 2.71 (IV), with IMR values of 28.23 (IC) and 22.27 (IV).
• Both CFR and IMR showed good correlation between IC and IV adenosine (R²=0.50 for CFR, R²=0.33 for IMR), with no significant intra-method variability.

Conclusions:

• IC adenosine demonstrates a strong correlation with IV adenosine for CFR and IMR measurements in bolus thermodilution CRT.
• The findings support IC adenosine as a potential alternative to IV adenosine for CRT.
• This offers a valuable option for clinicians managing patients with angina and non-obstructive coronary artery disease.