Assessment of coronary flow reserve by contrast-enhanced second harmonic echo Doppler

Coronary Flow and Reserve by Enhanced Transthoracic Doppler Trumps Coronary Anatomy by Computed Tomography in Assessing Coronary Artery Stenosis

We report the case of a 71-year-old patient with many risk factors for coronary atherosclerosis, who underwent computed coronary angiography (CTA), in accordance with the guidelines, for recent onset atypical chest pain. CTA revealed critical (>50% lumen diameter narrowing) stenosis of the proximal anterior descending coronary, and the patient was scheduled for invasive coronary angiography (ICA). Before ICA he underwent enhanced transthoracic echo-Doppler (E-Doppler TTE) for coronary flow detection by color-guided pulsed-wave Doppler recording of the left main (LMCA) and whole left anterior descending coronary artery (LAD,) along with coronary flow reserve (CFR) in the distal LAD calculated as the ratio, of peak flow velocity during i.v. adenosine (140 mcg/Kg/m) to resting flow velocity. E-Doppler TTE mapping revealed only mild stenosis (28% area narrowing) of the mid LAD and a CFR of 3.20, in perfect agreement with the color mapping showing no flow limiting stenosis in the LMCA and LAD. ICA revealed only a very mild stenosis in the mid LAD and mild atherosclerosis in the other coronaries (intimal irregularities). Thus, coronary stenosis was better predicted by E-Doppler TTE than by CTA. Coronary flow and reserve as assessed by E-Doppler TTE trumps coronary anatomy as assessed by CTA, without exposing the patient to harmful radiation and iodinated contrast medium.

Reduced coronary flow reserve and parasympathetic dysfunction in patients with cardiovascular syndrome X

OBJECTIVE

Although cardiovascular syndrome X was described many years ago, its causes are still unclear. Many studies have addressed the autonomic function, whereas others have investigated the coronary reserve. The purpose of this study was to investigate the correlations between parasympathetic dysfunction and coronary flow reserve deficiency.

BASIC METHODS

Eleven consecutive women suffering from cardiovascular syndrome X were enrolled in the study. All the patients underwent the analysis of heart rate and blood pressure variability, the cold face test and noninvasive evaluation of the coronary flow reserve by transthoracic echocardiography. Comparison was made with healthy volunteers.

RESULTS

Seven patients (64%) showed vagal impairment in the analysis of heart rate and blood pressure variability and a pathological response to the cold face test, whereas four patients (36%) did not show significant differences from the control group. In these three groups, patients with and without vagal impairment and controls, there was a difference in the mean diastolic coronary velocity reserve (1.94+/-0.48; 3.73+/-0.95, 2.88+/-0.55, P=0.0005) and in maximal diastolic velocity reserve (2.00+/-0.48, 3.26+/-0.64, 2.65+/-0.57, P=0.0047). Post-hoc analysis demonstrated that the mean and maximal diastolic velocity reserves of the patients with vagal impairment seemed to be reduced compared with those of the other groups (P<0.05), which were similar.

CONCLUSIONS

This study confirmed that syndrome X patients represent a heterogeneous group. More than half of the patients exhibited vagal dysfunction. In these patients, coronary flow reserve was abnormal compared with controls and other syndrome X patients without vagal impairment.