Author + information
- David Barton,
- Yiannis Chatzizisis,
- Feng Xie,
- Edward O'Leary,
- Gregory Pavlides and
- Thomas Porter
Background: Abnormal myocardial contrast enhancement with a continuous infusion of intravenous ultrasound contrast during demand stress reflects resistance changes at the mirovascular level that control coronary blood flow responses in response to an epicardial stenosis. We have previously demonstrated that these abnormal microvascular perfusion (MVP) responses may frequently occur even when fractional flow reserve (FFR) across the epicardial stenosis is considered normal. With the availability of hemodynamic wires capable of measuring both velocity and pressure distal to a stenosis, we hypothesized that MVP may correlate more closely with invasive measures of microvascular resistance.
Methods: In 20 consecutive patients (11 male, 9 female mean age 65 years; range 54-83 years) who underwent demand stress contrast echocardiography (10 exercise, 10 dobutamine) and who had an intermediate stenoses subtending a coronary artery territory (CAT) with stenosis range 50-75%) at subsequent coronary angiography, invasive coronary hemodynamics were obtained using a 0.014 inch Combo wire (Volcano, San Diego, CA). During intravenous adenosine infusion, measurements of FFR, coronary flow reserve (CFR), and hyperemic microvascular resistance (HMR) were obtained. CFR was defined as normal if >2.0, and HMR was defined as normal if <1.2 mm Hg/cm/sec. Normal FFR was >0.80. MVP during demand stress was considered abnormal only if independently confirmed by at least two expert reviewers.
Results: There were 16 coronary artery territories (CAT) in the 20 patients that were independently read as abnormal by contrast echocardiography. FFR was abnormal (<0.8) in only four of these CAT (25%), while CFR and HMR were abnormal in 11 (69%; p=0.01 compared FFR). There were three CAT where HMR was abnormal but MVP appeared normal.
Conclusions: Patients with abnormal myocardial perfusion during demand stress and intermediate stenoses at subsequent coronary angiography frequently have normal FFR values. In a majority of these patients, the perfusion abnormality is due to abnormal microvascular resistance.
Poster Hall, Hall C
Saturday, March 18, 2017, 9:45 a.m.-10:30 a.m.
Session Title: Innovative Use of Echocardiography
Abstract Category: 28. Non Invasive Imaging: Echo
Presentation Number: 1197-228
- 2017 American College of Cardiology Foundation