Coronary flow reserve of the angiographically normal left anterior descending coronary artery in patients with remote coronary artery disease

Abstract

Coronary artery disease (CAD) has been suggested to alter coronary flow reserve (CFR; the ratio between hyperemic and baseline coronary flow velocities) not only in territories supplied by stenotic arteries but also in angiographically normal, remote regions. However, few data exist regarding the left anterior descending (LAD) coronary artery as the normal index artery. The influence of remote CAD on CFR of the angiographically normal LAD was evaluated with transthoracic Doppler ultrasound to measure CFR in the LAD during 90 seconds of venous adenosine infusion (140 g/kg/min) in 122 subjects who were assigned to 1 group; group 1 comprised 49 controls without angiographically detectable CAD, and group 2 consisted of 73 patients with an angiographically normal LAD and remote CAD. Experimental and clinical reports have suggested that acute myocardial infarction decreases coronary flow reserve (CFR; the ratio between hyperemic and baseline flow velocities) not only in the infarctrelated artery but also in remote, angiographically normal coronary arteries. 1-5 Discordant results have been reported in patients without previous myocardial infarction, 6 -8 and it is unclear what the interaction is when the normal vessel is the left anterior descending (LAD) coronary artery. Recent advances in color Doppler technology have allowed imaging of the distal LAD 9,10 by transthoracic echocardiography, thereby opening the way to the noninvasive detection of recanalization in acute anterior myocardial infarction, 11 diagnosis of LAD disease by measurement of CFR, 12-15 and monitoring of changes in CFR after stenting. 16,17 The aim of this study was to assess whether CFR in an angiographically normal LAD is preserved in patients with remote coronary artery disease (CAD), including those with myocardial infarction. CFR was prospectively measured by transthoracic coronary Doppler ultrasound. METHODSStudy population: Patients were selected from a population undergoing diagnostic or therapeutic cardiac catheterization at our institution. The requisite to be enrolled in this study was the presence of an angiographically normal LAD with or without remote CAD. From June 2002 to August 2003, 122 consecutive subjects (105 men and 17 women; mean age 58 Ϯ 10, range 31 to 77) were recruited and assigned to 1 of 2 groups; group 1 comprised 49 controls with chest pain but no angiographically detectable CAD (i.e., coronary arteries with angiographically smooth silhouettes), and group 2 consisted of 73 patients with an angiographically normal LAD and remote CAD. Group 2 was further divided into 4 subgroups: 16 patients with remote percutaneous coronary intervention but no evidence of myocardial infarction (group 2A); 13 patients without remote myocardial infarction but significant (Ն70%) remote coronary stenosis (group 2B); 23 patients with remote myocardial infarction and previous remote percutaneous coronary intervention (group 2C); and 21 patients with remote myocardial infarction but no remote percutaneous coronary intervention (group 2D)....

Transthoracic Echocardiography in the Assessment of Coronary Arteries

“…It seems attractive and easy to detect coronary stenoses basing on the search of the aliasing zone and the measurement of peak diastolic flow velocity only, but both methods are semiquantitative and, unfortunately, inaccurate. As previously reported, laminar peak diastolic velocity in the coronary artery is from 0.21 ± 0.08 m/s (Youn et al, 2002 to 0.28 ± 0.09 m/s (Pizzuto F., 2004), and the velocity will not exceed 1 m/s even in case of its 3-4-fold increase in the stenosis site. So, local peak diastolic flow velocity >2.0 m/s is a highly specific, but low sensitive marker of coronary artery stenosis.…”

“…Pizzuto et al, 2001 revealed CFVR value for the LAD ranging from 2.90±0.58 to 3.050.81 in control group of patients with angiographically normal coronary arteries, and similar values for CFVR were found in <50% LAD in-stent restenosis (Lambertz et al, 1999;. Later, CFVR in angiographically normal LAD patients with remote CAD (presence of previous remote myocardial infarction and wall motion abnormalities) was determined also as preserved (Pizzuto et al, 2004). According to numerous studies using TTE the cut-off value of CFVR is generally accepted to be 2.0 for predicting significant LAD stenosis in patients under decision-making process, after intracoronary intervention, and with in-stent restenosis (table 6).…”

“…In previous works, control subjects with normal coronary angiograms and normal left ventricular systolic function showed that the peak diastolic velocity in distal LAD was 21.27.9 cm/s and the duration of diastolic coronary artery flow was 58.56.4% of the R-R interval at rest within the range of physiologic heart rates (60-100 b/m) (Youn et al, 2002). In studies including the participants without significant LAD stenosis, the peak diastolic velocity in distal LAD was ranging from 218 cm/s to 289 cm/s (Hozumi et al, 1998a(Hozumi et al, , 1998bYoun et al, 2002;Pizzuto et al, 2004). In our study (Boshchenko et al, 2008) …”

“…In one study, CFVR with a cut-off value <2.0 was a significantly better predictor (90%sensitivity, 96%specificity) of LAD stenosis than multidetector computed tomography (80%sensitivity, 93%specificity) and improved the diagnostic accuracy of the latter from 90 to 96% (Pizzuto et al, 2009). A cut-off value <2.0 was appropriate even for the diagnosis of significant stenosis of donor LAD giving collaterals to other arteries (Pizzuto et al, 2004;Iwata et al, 2006). Several investigators studied the accuracy of Doppler TTE measurement of CFVR in the PDA to detect stenosis in the RCA, and the same cut-off value of CFVR (<2.0), demonstrating sensitivity 84-89% and specificity 83-96%, was accepted for predicting significant RCA stenosis Takeuchi et al, 2004 Table 6.…”

Assessment of Fractional Flow Reserve in Patients With Recent Non–ST-Segment–Elevation Myocardial Infarction

“…23,24 As discussed above, this could potentially have implications for the assessment of FFR in nonculprit vessels in patients presenting with ACS.…”