Importance of diastolic fractional flow reserve and dobutamine challenge in physiologic assessment of myocardial bridging
Javier Escaned, MD, PhD*,*,
Jorge Cortés, MD*,
Alex Flores, MD, PhD*,
Javier Goicolea, MD, PhD*,
Fernando Alfonso, MD, PhD*,
Rosana Hernández, MD, PhD*,
Antonio Fernández-Ortiz, MD, PhD*,
Manel Sabaté, MD, PhD*,
Camino Bañuelos, MD* and
Carlos Macaya, MD, PhD*
* Interventional Cardiology Service, Cardiovascular Institute, Hospital Clínico San Carlos, Madrid, Spain
View larger version (22K):
[in a new window]
|
Figure 1 Angiographic characteristics of systolic vessel compression at baseline and at peak dobutamine challenge.
|
|
View larger version (125K):
[in a new window]
|
Figure 2 Modifications introduced by dobutamine challenge in the angiographic severity of left anterior descending myocardial bridging. With dobutamine challenge, systolic minimal luminal diameter decreased from 0.75 to 0.35 mm, and the length of the compressed segment increased from 23.65 to 36.91 mm.
|
|
View larger version (40K):
[in a new window]
|
Figure 3 Intracoronary hyperemic pressure measurements at baseline and during dobutamine challenge. The graph shows the recorded electrocardiogram (EKG), aortic pressure (Pa), and intracoronary pressure distal to the myocardial bridge (Pd) as well as the instantaneous pressure gradient resulting from the difference between the two pressures. These tracings are shown as recorded at baseline and during dobutamine challenge (note the differing scaling of the pressure tracings). The overshooting of Pd over Pa noted during dobutamine challenge contributes to the characteristic negative systolic and positive protodiastolic pressure gradients, which mimic the Doppler flow velocity pattern described previously (1,9). At baseline mean fractional flow reserve (FFR) was 0.90 and diastolic FFR was 0.87; during dobutamine challenge mean FFR was 0.80 and diastolic FFR was 0.72.
|
|
View larger version (28K):
[in a new window]
|
Figure 4 Fractional flow reserve (FFR) values obtained at baseline and at peak dobutamine challenge using either mean or diastolic FFR. The combination of dobutamine challenge and diastolic FFR allows identification of the largest number of patients in whom the optimal cutoff value for detection of hemodynamic relevance was reached.
|
|
View larger version (23K):
[in a new window]
|
Figure 5 Influence of the intracoronary systolic pressure gradients on the discrepancy between mean and diastolic fractional flow reserve (FFR) measurements, expressed as the ratio mean FFR/diastolic FFR. At baseline the discrepancy between the techniques is minimal and is not influenced by systolic gradients. Conversely, during dobutamine challenge a significant inverse relationship between intracoronary systolic gradient and the defined discrepancy develops, being maximal in those patients who developed negative systolic intracoronary pressure gradients.
|
|
|
