Global coronary flow reserve is associated with adverse cardiovascular events independently of luminal angiographic...

Area of Science:

• Cardiology
• Diagnostic Imaging
• Vascular Biology

Background:

• Coronary flow reserve (CFR) integrates assessments of focal, diffuse, and small-vessel coronary artery disease (CAD).
• CFR is a crucial indicator for identifying patients at elevated risk of cardiac mortality.
• This study investigated the relationship between CFR, angiographic CAD, and subsequent cardiovascular outcomes.

Purpose of the Study:

• To determine the association between noninvasively measured CFR and angiographic measures of CAD severity.
• To evaluate the independent and combined predictive value of CFR and angiographic CAD for adverse cardiovascular outcomes.
• To assess whether CFR modifies the impact of early revascularization on patient outcomes.

Main Methods:

• A cohort of 329 patients undergoing invasive coronary angiography after stress positron emission tomography (PET) was followed for a median of 3.1 years.
• Coronary artery disease (CAD) extent and severity were quantified using the CAD prognostic index.
• Noninvasive CFR was measured using PET, and cardiovascular outcomes (cardiac death, heart failure admission) were recorded.

Main Results:

• A modest inverse correlation was observed between CFR and the CAD prognostic index (r=-0.26; P<0.0001).
• Both CFR and CAD prognostic index were independently associated with adverse cardiovascular events after multivariable adjustment.
• Patients with low CFR exhibited event rates comparable to those with high angiographic scores, and the highest risk was observed in those with low CFR or high CAD prognostic index (P=0.001).

Conclusions:

• CFR is an independent predictor of cardiovascular outcomes, irrespective of angiographic CAD severity.
• CFR significantly modifies the effect of early revascularization, particularly in patients undergoing coronary artery bypass grafting.
• Diffuse atherosclerosis and microvascular dysfunction, reflected by low CFR, likely contribute to cardiovascular events and influence revascularization efficacy.