A 55-year-old man with a history of hypertension, hyperlipidemia, smoking, and gastroesophageal reflux disease (GERD) presents to the office with a 1-month history of intermittent epigastric discomfort associated with climbing stairs at work. The symptoms resolve with rest and are unlike his prior episodes of GERD. He takes hydrochlorothiazide 25 mg once daily, amlodipine 5 mg once daily, atorvastatin 40 mg once daily, and pantoprazole 40 mg once daily. The patient has a 30-pack-year history of smoking as well as a paternal history of coronary artery disease and cardiomyopathy.
On examination, his heart rate is 78 bpm, his blood pressure is 126/80 mmHg, and the rest of his vital signs are normal. His electrocardiogram is normal. He undergoes transthoracic echocardiography that shows normal regional wall motion and ejection fraction of the left ventricle. A coronary computed tomography angiogram (CCTA) demonstrates a non-calcified plaque in the proximal right coronary artery (RCA) interpreted as 25-49% stenosis, a calcified plaque in the left circumflex artery (LCX) interpreted as 25-49% stenosis, and no plaque in the left anterior descending artery (LAD). The patient is concerned about his risk factors and asks you if further analysis can be done to guide medical decision-making. You consider perivascular fat attenuation index (FAI) as an option.
The correct answer is: B. Perivascular FAI mapping can be used to risk stratify patients with anginal symptoms in terms of cardiovascular mortality.
Perivascular FAI is a novel and noninvasively measured marker of coronary inflammation that can be measured on a CCTA. Perivascular FAI detects inflammation-induced changes in the coronary perivascular fat attenuation, thereby enabling early detection of coronary inflammation. Higher perivascular FAI values were associated with a higher risk of all-cause and cardiac mortality in patients undergoing a CCTA in the recent CRISP-CT (Cardiovascular Risk Prediction Using Computed Tomography) study.1 However, this association between perivascular FAI and cardiac mortality was found only in analysis of proximal RCA and LAD territories and but not the LCX.
Perivascular FAI can be used regardless of underlying visible coronary lesions and can be utilized to incrementally increase prognostication of current models utilizing CCTA to predict adverse events. Perivascular FAI can quantify the residual inflammatory risk and can be used for risk re-stratification in both primary and secondary cardiovascular disease prevention. Integrating perivascular FAI into modern CCTA interpretation will facilitate identification of individuals at risk of future cardiac death, before structural changes of the coronary wall are visible, and will flag so-called vulnerable patients with inflamed coronary atheroma who might be candidates for more intensive treatment. Whether this information can be used to identify candidates for the new anti-inflammatory agents (e.g., canakinumab) or PCSK9 inhibitors, in addition to optimal medical therapy, to target their residual cardiovascular and inflammatory risk should be explored in future studies.
- Oikonomou EK, Marwan M, Desai MY, et al. Non-invasive detection of coronary inflammation using computed tomography and prediction of residual cardiovascular risk (the CRISP CT study): a post-hoc analysis of prospective outcome data. Lancet 2018;392:929-39.