Rostislav S. Karpov

Simultaneous transesophageal Doppler assessment of coronary flow reserve in the left anterior descending artery and coronary sinus allows differentiation between proximal and non-proximal left anterior descending artery stenoses.

AIM AND METHODS The role of simultaneous transesophageal Doppler assessment of coronary flow reserve (CFR) in the left anterior descending artery (LAD) and coronary sinus (CS) in the diagnostics of hemodynamically significant LAD stenoses of various localization was studied in 16 CAD patients with angiographically proven >50% stenotic atherosclerosis of the LAD (nine--in the proximal third, seven--in the mid and/or distal third) and 23 healthy volunteers (all men). Dipyridamole was used as a stress agent. The diastolic phase of coronary flow in the LAD and the antegrade phase of coronary flow in the CS were analyzed. CFR in the LAD and CS was calculated in two ways: one--as ratio of peak hyperemic flow velocity to the peak baseline blood flow velocity (CFR by Vp); two--as ratio of volume hyperemic blood flow velocity to the volume baseline blood flow velocity (CFR by VBF). The level of the CFR <2 in both ways of calculation was diagnosed as reduced. RESULTS It was found that in CAD patients with LAD proximal stenosis the values of CFR in the LAD were significantly lower than those in healthy individuals by both Vp (1.87 +/- 0.43 and 3.54 +/- 0.82; P<0.001) and VBF (1.79 +/- 0.77 and 3.85 +/- 1.25; P<0.01). In proximal stenosis CFR in the LAD by Vp was significantly lower than that in non-proximal stenosis (1.87 +/- 0.43 and 3.31 +/- 1.44; P<0.05). Sensitivity and specificity of CFR <2 in the LAD by Vp in the diagnostics of LAD proximal stenosis were 56% and 97%, respectively; and CFR <2 in the LAD by VBF--89% and 93%, respectively. In CAD patients with both proximal and non-proximal LAD stenoses CFR in the CS by Vp was significantly lower than that in healthy volunteers and was 1.74 +/- 0.53, 1.63 +/- 0.30 and 2.56 +/- 0.87; P<0.05, respectively. Sensitivity and specificity of CFR <2 in the CS by Vp in the diagnostics of hemodynamically significant LAD stenoses were 75% and 70%, respectively. The values of CFR in the CS by VBF in CAD patients and healthy volunteers did not differ significantly. CONCLUSIONS Thus, simultaneous evaluation of CFR in the LAD and CS makes it possible to diagnose hemodynamically significant LAD stenoses and to differentiate between proximal and non-proximal impairments.

Transthoracic echocardiography in the detection of chronic total coronary artery occlusion

AIMS The aim of our study was to detect chronic total occlusion of the left anterior descending coronary artery (LAD), circumflex coronary artery (Cx), and right coronary artery (RCA) using transthoracic echocardiography (TTE) in 110 consecutive patients who underwent coronary angiography for investigation of angina. METHODS AND RESULTS Coronary blood flow direction was assessed in the epicardial collaterals [distal LAD (dLAD), obtuse marginal branches and right posterior descending artery (PDA)] and intramyocardial collaterals [LAD septal branch (SB LAD) and RCA septal branch (SB RCA)]. The sensitivity and specificity of retrograde flow for identification of the occluded LAD by TTE in the dLAD only were 78 and 96%, respectively, and those in both dLAD and SB LAD were 89 and 96%, respectively. The retrograde SB LAD flow detects proximal LAD occlusion with 88% sensitivity and 75% specificity. The sensitivity and specificity of retrograde flow for identification of the occluded RCA by TTE in the PDA only were 79 and 97%, respectively, and those in both PDA and SB RCA were 89 and 97%, respectively. The retrograde SB RCA flow does not allow us to differentiate between proximal and non-proximal RCA occlusion. Transthoracic echocardiography is not a method for diagnosing Cx occlusions as the success in visualizing the Cx epicardial collaterals was achieved in 31% of cases only. CONCLUSION TTE is a sensitive and highly specific non-invasive method for diagnosis of LAD and RCA occlusions, based on the detection of the coronary blood flow direction in the epicardial and intramyocardial collaterals.

Transthoracic Echocardiography in the Assessment of Coronary Arteries

Quantitative coronary angiography remains the reference standard for assessing coronary anatomy, measuring anatomic severity of the stenotic lesion and assisting in the process of intracoronary interventions. Thus, treatment of coronary artery disease (CAD) is performed primarily on the basis of anatomic measurements of stenosis severity, although the disease severity correlates better with physiologic disturbances which can be revealed by the analysis of coronary artery flow and coronary flow reserve (CFR). Direct invasive measurements of coronary flow signal using Doppler flow wires and catheters provide a lot of information on the pathophysiology of coronary flow dynamics (Chamuleau et al, 2001; Bax et al, 2006; Braden, 2006; Werner et al., 2006; Kaul & Jayaweera, 2008; Courtis et al., 2009). But in clinical practice, these invasive techniques are rarely applied because of the time and expense required. Alternative methodology in detecting coronary flow and CFR is positron emission tomography which is feasible but expensive and scarcely available (West & Kramer, 2009). In fact, a large-scale assessment of such important functional parameters is hampered by the lack of a reliable, low-cost, noninvasive method that might be used for this purpose (Pellikka, 2004). Some years ago transesophageal echocardiography was proposed for evaluation of coronary flow and CFR in man. However, this method demonstrates some important limitations: it is semiinvasive, and has optimal feasibility in visualizing the flow in only very proximal part of the left anterior descending coronary artery (LAD) (ranging from 69% to 97%) and right coronary artery (RCA) (ranging from 66% to 83%) which allowes the assessment of transstenotic or prestenotic CFR but not poststenotic CFR (Vrublevsky et al., 2001, 2004). Until recently, transthoracic echocardiography (TTE) evaluation of the CAD was aimed at the assessment of regional and global left ventricular function (Youn & Foster, 2004). Direct transthoracic visualization of the coronary arteries was attempted in children and occasionally in adults with coronary artery anomalies, arteriovenous fistulas, and aneurysms (Harada et al., 1999; Hiraishi et al, 2000; P.C. Frommelt & M.A. Frommelt, 2004). However, with the advent of harmonic imaging, contrast agents and high-frequency transducers, direct transthoracic Doppler visualization of non-dilated arteries and measurement of coronary artery flow is now relevant in the majority of patients. The aims of this review are to outline the technical aspects of coronary artery visualization and flow measurements both at rest and with pharmacological stress, to demonstrate pathologic coronary artery flow patterns by TTE and to discuss clinical implications of TTE for patients with suspected or confirmed CAD.

1073 Transthoracic doppler analysis of coronary artery poststenotic flow characteristics in the mid and distal left anterior descending coronary artery

Eur J Echocardiography Abstracts Supplement, December 2006 Results: The two groups were similar for sex, age, heart rate, body mass index, systolic and diastolic blood pressure (BP), LV mass, relative wall thickness, transmitral E/A ratio and deceleration time. CBF diastolic peak velocity at rest was higher in patients with E/Em ratio≥8 (26.0±0.6 cm/s) than in those with E/Em ratio<8 (22.3±0.6 cm/s) (p<0.01). In the overall population, resting CBF diastolic velocity was positively related with E/Em ratio (r=0.40, p<0.01). This association remained significant even after controlling for diastolic BP and LV mass (r=0.37, p<0.02). Conclusions: In uncomplicated arterial hypertension CBF at rest is increased in presence of increased E/Em ratio, independently of BP values and LV hypertrophy. These findings indicate that the increase of LV filling pressure occurring during pressure overload is able itself to induce elevation of coronary microvascular resistance and, thus, of CBF velocities at baseline condition.

1131-149 Reduced coronary flow reserve in the coronary sinus is a predictor of hemodynamically significant stenoses of the left coronary artery territory

AIM AND METHODS The role of transesophageal Doppler assessment of coronary flow reserve (CFR) in the coronary sinus (CS) in the diagnostics of significant left coronary artery (LCA) stenoses was studied in 65 CAD patients with angiographically proven >50% stenotic atherosclerosis of the LCA territory (38--with isolated left anterior descending artery (LAD) or left circumflex artery (Cx) stenosis; 27--with both LAD and Cx stenoses) and 31 healthy volunteers (all men). Dipyridamole was used as a stress agent. The antegrade phase of coronary flow in the CS moving into the right atrium was analysed. CFR in the CS was calculated in two ways: (1) as ratio of hyperemic to baseline peak antegrade flow velocity (CFRp); (2) as ratio of hyperemic to baseline volumetric blood flow velocity (CFRv). The level of CFR <2.0 in both ways of calculation was diagnosed as reduced. RESULTS CAD patients compared with healthy volunteers had significantly lower CFRp (1.51+/-0.44 and 2.57+/-0.79; p<0.001) and CFRv (2.21+/-1.18 and 5.43+/-2.83; p < 0.001) in the CS. CFRp <2.0 in the CS was a predictor of significant stenoses of the LCA with sensitivity of 89% and specificity of 76%, while CFRv <2.0 was a predictor of significant stenoses of the LCA with sensitivity of 49% and specificity of 97%. CFRp <2.0 in the CS was registered in 96% of CAD patients with two-vessel lesion and in 84% of CAD patients with one-vessel lesion, while CFRv <2.0 in the CS was revealed in 85% of CAD patients with two-vessel lesion and only in 26% of CAD patients with one-vessel lesion. Sensitivity and specificity of CFRv <2.0 in the CS in the diagnostics of significant two-vessel lesion of the LCA were 85% and 84%, respectively. CONCLUSIONS Thus, the reduced CFR in the CS is a sensitive and specific predictor of LCA stenoses. A decrease of both CFRp <2 and CFRv <2.0 in the CS is a predictor of significant two-vessel lesion of the LCA, while a decrease of only CFRp <2.0 in the CS is a predictor of significant one-vessel lesion of the LCA.

Simultaneous transesophageal doppler estimation of coronary flow reserve in the left descending artery and coronary sinus in the differentiation of proximal and nonproximal left descending artery stenoses

The aim of our study was the differentiation of proximal and non-proximal left descending artery (LDA) stenoses with simultaneous assessment of coronary flow reserve (CFR) in the LDA and coronary sinus (CS) in CAD patients with single-vessel LDA stenosis using multiplane transesophageal echocardlography. Methods: We studied 17 men (mean age 46~7 years) with over 50% single-vessel LDA stenosis, confirmed with quantitative coronary angiography. Nine patients with over 50% smgle-vessel proximal LDA stenosis were included in group la. Eight patients with over 50% stenosis of the LDA mid and/or distal third composed group lb. The control group (II) consisted of 25 healthy volunteers (men, mean age 35*5 years). Transesophageal Doppler assessment of coronary blood flow in proximal LDA and CS was performed at baseline and after intravenous dipyridamole (0,56 mg/kg for 4 minutes) using ultrasound diagnostic systems HDI 5000 SonoCT and Ultramark 9 HDI CV (Philips-ATL). CFR was calculated as the ratio of hyperemic to baseline peak diastolic velocities I” the LDA and CS. Results: The baseline peak diastolic velocltvas of blood flow in the LDA and CS did not differ significantly in groups la, lb and II, and were 52+27 cm/s, 39*13 cm/s. 37+11 cm/s for the LDA, and 32ill cm/s, 34+8 cm/s. 3&l 1 cm/s for the CS, respectively. In group la CFR in the LDA was significantly reduced, compared to groups lb and II, and made 1.87eO.43. 3.23el.35 and 3.51kO.79, p<O.Ol, respectively. We revealed a reverse correlation between the LDA stenosis area and CFR in this artery (r=-0.60, pcO.001). CFR in the LDA <2 had a positive predictive accuracy of 83% in the diagnostics of proxlmal stenoses. A signtficant diminution of CFR in the CS was determined in CAD patients of both the groups when compared with healthy volunteers and was 1.74eO.53, 1.63*0.30. 2.56i0.87 for groups la, lb, II, respectively (p la-11 cO,O5, p lb-11 <0,05, p la-lb =ns). CFR ~2 in the CS had a positive predictive accuracy of 63% in the diagnosttcs of LDA stenosis of any localization. Thus. reduced CFR in the LDA is a predictor of proximal LDA stenosis. Reduced CFR in the CS IS a predictor of stenosis in both the proximal and non-proximal LDA segments.

849 Detection of left coronary artery stenoses using transesophageal Doppler assessment of coronary flow reserve in the coronary sinus

examiners. Results: The mean IMT-Carotid was 1.0±0.2 mm (0.6-2.1 mm), the Plaque-Ao 2.9±1.7 mm (0.6-10.0 mm). Both IMT-Carotid and Plaque-Ao correlated signifi- cantly with age (r=0.45, p 0.9 mm for a Plaque-Ao of >4.0 mm was only 28% (60 of 214 patients). Conclusion: Due to the high negative predictive value of the IMT-Carotid, TEE of the thoracic aorta appears to be dispensable in patients with ischemic insult and an IMT-Carotid <0.9 mm. An elevated IMT-Carotid increases the probability of relevant atherosclerosis of the aorta, but is not definitively predictive in the individual case. Therefore, sonographic examination of the carotid arteries should be supplemented with transesophageal echocardiographic examination of the aorta in these patients.