JACC February 2001 ABSTRACTS - Noninvasive Imaging 379A 1031-l 35 Predictors of Left Atrial Appendage Clot: A Transesophageal Echocardiographic Study of Left Atria! Appendage Function in Patients With Severe Mitral Stenosis Kewal C. Goswami, Rakesh Yadav, M. Bhaskararao, Vinay K. Bahl, Kewal K. Talwar, Subhash C. Manchanda. Cardiothoracic Sciences Center, A// India Institute of Medical Sciences, New Delhi, India Background: Left atrial appendage (LAA) is the major site of clot formation in severe mitral stenosis (MS). There are not enough studies properly evaluating LAA function in a large number of patients (pts) with isolated severe MS. The purpose of this study was to analyze the LAA function with LAA clot and spontaneous echo contrast (SEC). Method: LAA function [LAA-ejectlo” fraction (EF), peak filling and emptying velocities and their velocity time integrals (VTls)] was prospectively evaluated I” 200 consecutive pls (mean age 30.2 r 9.4 years, 51.5% females) of severe MS by transesophageal echocardio- graphy (TEE). Pts with more than mild mitral regurgitation, significant aortic valve dis- ease, previous valvulotomy and on anticoagulatlon or antiplatelet therapy were excluded. Twenty normal controls were compared. Result: Fifty five (27.5%) were in atrial fibrilla- tion (AF). LAA clot was present in 25% pts and 56.5% had SEC. On univariate analysis the older age, increased duration of symptoms, AF, SEC, larger LA area, depressed LAA function and type II and III-LAA flow patter” correlated significantly (~~0.05) with LAA clot. LAA-EF was significantly less in pts with clot (21.8 + 12.8% Vs 39.1 t 13.2%, p<O.OOOl) and with SEC (30.3 r 16.2% Vs 40.3 i 11.3%, p<O.OOl). LAA filling (16.0 * 11.7 Vs. 27.6 f 11.8 cm/s, p<O.OOl) and emptying (15.4 ? 7.0 Vs 21.5 + 9.6 cm/s, p<O.OOl) velocities and filling (1.4 t 1 .O Vs 2.5 f 1.4 cm, p<O.OOOl) and emptying (1.5 + 1.2 Vs 2.1 f 1.2 cm, ~~0.05) VTls were also significantly lower in pts with clot. Similarly pts with SEC had significantly lower fliling and emptying velocities and VTls. On multivari- ate regression analysis, AF and LAA-EF were the only independent predictors of LAA clot formation. Pts with LAA-EF < 25% had 62.5% incidence of clot as compared to 10.4% with LAA-EF >25%. In a subgroup of the pts with sinus rhythm (NSR) the LAA-EF was significantly less in pts with clot (31.2 + 13.2 Vs 41.2 + 11.5% p<O.Ol) and was the only predictor of clot formation. Conclusion: We conclude that in the pts with severe MS, besides AF, a subgroup of pts in NSR with depressed LAA -EF (< 25%) had a higher risk of LAA clot formation and we suggest that these pts should be routinely anticoagulated for prevention of LAA clot. 1031-136 High Grade Left Atrial Spontaneous Echo Contrast Is a Potential Risk for Micro-Emboli in Cerebral Circulation in Patients With Atrial Fibrillation Under Anticoagulants Yoshio Yamanaka, Hiroya Kawai, Katsuya Hata, Hideyuki Takaoka, Toshiro Shinke, Yoichi Ktjima, Takeomi Murata, Soichiro Ota, Yoke Miyata, Yoshiaki Ueda, Fiyouhei Yoshikawa, Osamu Iseki, Yasuaki Matsuda, Horuka Akita, Mitsuhiro Yokoyama. The fstDept. of /&ma/ Medicine,Kobe Univerwy School of Medicine, Kobe, Japan Background. Presence of left atrial spontaneous echo contrast detected in patlents with atrial fibrillation has been reported as a potential risk factor for cerebral ischemic event. However, whether spontaneous echo contrast in left atrial cavity is the actual source of micro-emboli in cerebral circulation remains to be clarified. Methods. Study patients con- sisted of 24 chronic atrial fibrillation patients, who received anticoagulant therapy (pro- thrombin time 1.83 f 0.16 INR). We evaluated spontaneous echo contrast in the left atrial quantitatively as a” integrated backscatter intensity using transesophageal echocardio- graphy. Calibrated -left atrlal integrated backscatter was caluculated as difference between digital integrated backscatter image sequences of the left atrial cavity and the right atrial cavity under the same gain settings in all patients. Then, we estimated micro- emboli in middle cerebral arteries as the counts of high intensity transient signals during 30 minutes in transcranial Doppler recordings. Results. In all patients, integrated back- scatter in the left atrial exceeded that in right atrial. Calibrated lefl atrial - integrated back- scatter was closely correlated with high intensity transient signals counts (p<O.OOO5,r=O.69). Conclusions. Atrial fibrillation patients with high grade spontaneous echo contrast in the left atrial have frequent incidence of mere-emboli in middle cerebral arteries, in whom more intensive anticoagulant therapy will be required. POSTER SESSION 1031 Echo Assessment of the Left Atrium and interatriai Septum Sunday, March 18, 2001, Noon-2:00 p.m. Orange County Convention Center, Hall A4 Presentation Hour: Noon-i :00 p.m. 1031-133 Degree of Patent Foramen Ovale Shunting Quantified by Transthoracic Transmitral Doppler Is Associated With Likelihood of Cryptogenic Cerebral lschemic Events Andrew J. Kerr, Michael H. Picard. Chi-Ming Chow, Robert A. Levine, Lee H. Schwamm. Massachusetts Genera/ Hospital, Boston, MA Background: Despite a 20 to 30 percent incidence of patent foramen wale (PFO) in the general population, strokes attributable to paradoxical embolism are uncommon. A “on- invasive method to identify those patients at higher risk of stroke due to paradoxical embolism would provide a rational basis for treatment decisions. Aims: This study com- pared the degree of trans.PFO shunting in patients with cerebral ischemia and PFO using transmitral Doppler (TMD), a recently validated transthoracic echo (TTE) method to quantify bubble passage. Patients without additlonal risk factors other than PFO (crypto- genie events) may have a greater degree of shunting. Methods: TMD recordings are made at the mitral leaflet tips during saline contrast study at rest and after a maneuver to provoke right-to-left shunt. Bubble transit corresponded to high intensity signals in the velocity envelope of the mitral inflow profile. Bubble transit is quantified by taking the Integral of the acoustic power within the maximal mitral envelope during contrast injection, divided by the integral of the acoustic power before contrast for any given patient. lschemlc events were classified as cryptogenic (C) or non-cryptogenic (NC) according to TOAST criteria. Results: 32 of 101 (32%) consecutive patients referred for TTE TMD saline contrast study after cerebral ischemic events had a PFO detected. Of these 32, 21 (66%) had cryptogenic vs. 11 (33%) had non-cryptogenic events. Bubble passage measured by “or- malized acousiic power was significantly greater in the C group than in the NC group after the provocative maneuver. NC (n=l 1) c (n=21) Rest 45+86 65+82 P = 0.07 MatlelWr 57+86 94+78 P = 0.03 Patlents with > 5 bubbles in the maximal beat were more likely to have a cryptogenic stroke, both at rest (OR = 9, p = 0.02), and with maneuver (OR=7.92, p = 0.03). Conclusions: Because larger shunts detected by transthoracic TMD are associated with otherwise cryptogenic events, the technique may be useful in the decision analysis of PFO closure after cerebral ischemia. 1031-134 lnteratrial Septal Aneurysms Predict Larger Shunts Across Patent Foramen Ovales: An Analysis by Transmitral Doppler Ervin R. Fox, Michael H. Picard, Chl-Ming Chow, Robert A. Levine, Andrew J. Kerr. Massachusetts General Hospital, Boston. MA Background: The association of patent foramen wale with cryptogenic stroke is stron- gest in patients with larger trans-PFO shunts and those with interatrial septal aneurysms (IASA). We postulate that the potency of IASA as a risk factor for cerebrovascular acci- dents may relate to the size of the shunt across PFOs associated with IASAs. The size of shunt in PFOs associated with IASAs is unknown. Purpose: We compared the degree of right to left shunting across PFOs in patients with and patients without IASA using the recently validated transmitral Doppler (TMD) tech- nique. Methods: Consecutive patients referred for transthoracic saline contrast study were entered. All had transthoracic 2D and TMD contrast studies. TMD recordings were made at the mitral leaflet tips during saline contrast study at rest and after a maneuver to increase right to left shunting. Bubble transit corresponded to high intensity signals in the velocity envelope of the mitral inflow profile. Bubble transit in the maximal mitral profile is reported semi-quantitatively using a 0 to 4 bubble score (0 = no bubbles; 1 = 1 to 5 bub- bles; 2 = 6 to 10 bubbles; 3 = >lO bubbles without envelope saturation ; 4 = envelope sat- uration). TMD score has been shown to correlate defect size with the severity of shunt. IASA was present if 1) the base width 2 1.5 cm and 2) 2 1.1 cm excursion into either the left or the right atrium or a sum of the total excursion into the left or right atrium oft 1 .l Cm. Results: Of 160 consecutive patients 57 had a PFO. Of these, 19 patients had IASAs. Atrial septal motion could not be assessed in three (3) patients due to study quality. Bub- ble scores were significantly higher (p = 0.0001) among patients with IASAs. Of note, all patients with IASA had bubble scores of 2 3. TMD Bubble Score IASA (n = 19) No IASA (n = 35) 0 0 3 1 0 10 2 0 9 3 5 9 4 14 4 Conclusion: lnteratrial septum aneurysms are associated with larger right-to-left shunts across PFOs. This observation may have important diagnostic and management implica- tions in patients with unexplained stroke and IASA. POSTER SESSION 1032 Cardiovascular Magnetic Resonance: Plaque and Lumen Sunday, March 18, 2001, Noon-2:00 p.m. Orange County Convention Center, Hall A4 Presentation Hour: Noon-l :00 p.m. 1032-137 Feasibility of Using High Resolution MR Imaging of Atherosclerotic Plaque in an Epidemiological Study Chun Yuan, Shaoxiong Zhang, Norman J. Beauchamp. Department of Radiology, University of Washington, Seattle, WA, Johns Hopkins Medical Institutions, Baltimore, MD Background: It has been previously shown that magnetic resonance imaging (MRI) is capable of identifying various atherosclerotic plaque tissue types and monitoring the pro- gression of lesions. This study is to demonstrate the feasibility of performing high resolu- tion (HR) carotid MRI of atherosclerotic plaque in a” epidemiological study.