Koichi Toyonaga

Pseudonormalized Doppler total ejection isovolume (Tei) index in patients with right ventricular acute myocardial infarction.

The Doppler total ejection isovolume (Tei) index is useful for estimating global cardiac function. However, the relation between the right ventricular (RV) Tei index and RV infarction has not been investigated. The relation between the RV Tei index and severity of RV infarction was evaluated in 25 patients with inferior wall acute myocardial infarction (13 with and 12 without RV infarction). RV infarction was diagnosed when right atrial pressure was > or = 10 mm Hg or when right atrial pressure/pulmonary capillary wedge pressure was >0.8 by catheterization. The RV Tei index was significantly increased in patients with RV infarction compared with those without (0.53 +/- 0.15 vs 0.38 +/- 0.14, p <0.05). The RV Tei index in patients with severe RV infarction (right atrial pressure > or = 15 mm Hg) was significantly smaller compared with those with mild/moderate RV infarction (right atrial pressure <15 mm Hg) and showed no significant difference in patients with myocardial infarction but without RV infarction (0.44 +/- 0.09 vs 0.61 +/- 0.16 vs 0.38 +/- 0.14, severe RV infarction vs mild/moderate RV infarction vs no RV infarction, p <0.01). The RV Tei index is generally increased in patients with RV infarction; however, severe RV infarction can be manifested with limited or no increase in the Tei index (pseudonormalization).

Noninvasive evaluation of coronary reperfusion by transthoracic Doppler echocardiography in patients with anterior acute Myocardial Infarction before coronary intervention

Background—Transthoracic Doppler echocardiography (TTDE) enables evaluation of distal left anterior descending coronary artery (LAD) flow. The purpose of this study was to test whether TTDE can differentiate coronary reperfusion with Thrombolysis in Myocardial Infarction (TIMI) grade 3 from TIMI grade ≤2 in patients with anterior acute myocardial infarction (AMI). Methods and Results—In 46 consecutive patients with a first anterior AMI in the acute phase before emergent coronary intervention, the presence of antegrade distal LAD flow and its diastolic peak velocity were evaluated by color and pulsed TTDE and compared with TIMI grades by subsequent coronary angiography performed 29±12 minutes later. Nineteen patients had TIMI 0 reperfusion, 4 had TIMI 1, 10 had TIMI 2, and 13 had TIMI 3. Visual antegrade distal LAD flow was present in 22 of the 46 patients. TIMI 2 and 3 reperfusions were both generally visualized by color TTDE. However, peak distal LAD flow velocity by pulsed TTDE was significantly greater in patients with TIMI 3 compared with those with TIMI 2 (40±10 vs 20±6 cm/s, P <0.0001). The diagnosis of TIMI 3 based on diastolic peak distal LAD flow velocity ≥25 cm/s by TTDE had a sensitivity, specificity, and accuracy of 77%, 94%, and 89%, respectively. Conclusion—TTDE enables noninvasive differentiation of TIMI 3 from TIMI ≤2 coronary reperfusion in patients with AMI in the acute phase before emergent coronary intervention.

Transesophageal doppler echocardiographic assessment of left coronary blood flow velocity in chronic aortic regurgitation

Assessment of systolic and diastolic coronary blood flow velocities (FVs) in patients with aortic regurgitation (AR) has remained a clinical challenge. We recorded left anterior descending coronary blood FV in 21 patients with chronic AR an in 6 control subjects using transesophageal pulsed Doppler echocardiography. In 7 patients FV was measured 4.0 +/- 5.2 months after aortic valve replacement. Peak and mean FVs during systole and diastole and systolic/diastolic ratios of these FVs were determined. Left ventricular (LV) mass index was calculated by means of standard M-mode echocardiography. In patients with severe AR, peak and mean systolic FVs were significantly increased (34 +/- 8 cm/sec and 21 +/- 6 cm/sec, respectively) compared with FVs in the control group (15 +/- 4 and 12 +/- 3 cm/sec, respectively) and in patients with mild AR (17 +/- 3 cm/sec and 13 +/- 2 cm/sec, respectively). Peak and mean systolic FVs were also significantly increased in severe AR (54 +/- 13 cm/sec and 33 +/- 9 cm/sec, respectively) compared with FVs in the control (30 +/- 8 cm/sec and 21 +/- 5 cm/sec, respectively) and mild AR groups (30 +/- 5 cm/sec and 21 +/- 4 cm/sec, respectively). Peak systolic and diastolic FVs were correlated significantly with LV mass index (r = 0.72 and r = 0.73, respectively). Systolic and diastolic FVs and LV mass index were significantly decreased, normalized or both after aortic valve surgery. In conclusion, LV mass seems to have an effect on the significantly increased systolic and diastolic left coronary blood FV pattern in patients with chronic, severe AR. Increased systolic and diastolic FV appears to be normalized in the late period after surgery.

Noninvasive Evaluation of Coronary Reperfusion by CT Angiography in Patients With STEMI

OBJECTIVES The aim of this study was to determine whether 64-slice multidetector computed tomography (MDCT) can differentiate coronary reperfusion with Thrombolysis In Myocardial Infarction (TIMI) flow grade 3 from TIMI flow grade ≤ 2 after ST-segment elevation myocardial infarction (STEMI). BACKGROUND Multidetector computed tomography has become a popular modality for noninvasive coronary artery imaging. Recently, 64-slice MDCT has been applied to evaluate coronary arteries in acute coronary artery disease. METHODS The presence or absence of distal reperfusion in infarct-related arteries (IRA) was visualized with 64-slice MDCT during the acute phase in 87 non-high-risk patients after STEMI. To differentiate TIMI flow grade 3 from TIMI flow grade 2, we calculated the computed tomography (CT) number ratio by dividing the CT number of the contrast-enhanced coronary lumen at the most distal IRA by that at the proximal site to the culprit lesion in patients with reperfusion on MDCT. The MDCT findings were compared with TIMI flow grade with invasive coronary angiography (ICA) performed 20 ± 5 min later. RESULTS According to ICA, 58 patients had TIMI flow grade 0 or 1, 17 had TIMI flow grade 2, and 12 had TIMI flow grade 3, whereas distal reperfusion was evident on MDCT in 28 of the 29 patients with TIMI flow grade ≥ 2 and absent in 55 of the 58 with TIMI flow grade ≤ 1. The CT number ratio was significantly higher in TIMI flow grade 3 than in TIMI flow grade ≤ 2 (0.64 ± 0.11 vs. 0.37 ± 0.12; p < 0.0001). The sensitivity, specificity, and accuracy of a diagnosis of TIMI flow grade 3 on the basis of a CT number ratio of ≥ 0.54 that was an optimal cutoff value determined by receiver-operator characteristic curve analysis were 92%, 97%, and 97%, respectively. CONCLUSIONS Visualization of the IRA by 64-slice MDCT enables noninvasive differentiation of angiographic TIMI flow grade 3 from TIMI flow grade ≤ 2 coronary reperfusion during the acute phase in patients with STEMI.

Transesophageal Doppler echocardiographic assessment of systolic and diastolic coronary blood flow velocities at baseline and during adenosine triphosphate–induced coronary vasodilation in chronic aortic regurgitation

Few reports exist on the changes in systolic and diastolic coronary flow velocities (CFVs) at baseline and during coronary vasodilation in patients with chronic aortic regurgitation (AR). We examined the left anterior descending CFVs in 21 patients with AR (11 patients with mild AR and 10 patients with moderate to severe AR), 9 patients without AR (no AR group), and 6 patients who had undergone surgery for moderate to severe AR (postoperation group) with transesophageal Doppler echocardiography. Adenosine triphosphate (ATP) was infused into a peripheral right arm vein at four different doses (35, 70, 100, and 140 micrograms/kg/min). Coronary flow velocity response in systole and diastole was calculated as the ratio of systolic peak and mean and diastolic peak and mean CFVs during maximal ATP infusion to those at baseline. The systolic peak and mean CFVs and the diastolic peak and mean CFVs at baseline were significantly increased in the moderate to severe group compared with those in the other groups (p < 0.05, respectively). Systolic and diastolic CFVs were significantly increased during ATP infusions in the four groups. No significant differences of systolic and diastolic CFVs were observed among the four groups during maximal ATP infusion. The coronary flow velocity response calculated from the peak and mean diastolic CFVs were significantly decreased in the moderate to severe group (1.6 +/- 0.3 and 1.7 +/- 0.4) compared with those in the other three groups (3.6 +/- 0.7 and 3.2 +/- 1.1 in the no AR group, 2.6 +/- 0.6 and 2.5 +/- 0.4 in the mild group, and 2.5 +/- 0.7 and 2.4 +/- 0.6 in the postoperation group) (p < 0.05, respectively). In conclusion, the systolic and diastolic left CFVs at baseline appeared to be significantly increased in patients with moderate to severe chronic AR. However, the velocities during coronary vasodilation by ATP were equal to those in other groups, resulting in a decrease of coronary flow velocity response in systole and diastole.

Usefulness of adenosine triphosphate-atropine stress echocardiography for detecting coronary artery stenosis

There have been few studies on adenosine triphosphate (AT) stress echocardiography. The AT stress test may have fewer adverse effects than the adenosine stress test. The addition of atropine to AT echocardiography may enhance the sensitivity for detection of coronary artery disease (CAD). The purpose of this study was to determine the utility of AT-atropine echocardiography for detection of CAD. The group studied consisted of 112 patients with suspected CAD. Sixty-one patients did not have a history of prior myocardial infarction (group I) and 51 patients did (group II). AT was infused intravenously at 180 microg/kg/min for 14 minutes. Atropine (0.25 mg intravenously, repeated up to maximum total dose of 1 mg) was administered starting after 8 minutes of AT infusion. Ischemic response was defined as new or worsening wall motion abnormality occurring during the infusion. The sensitivity and specificity for detection of CAD were assessed using the representative echocardiograms during single AT infusion and AT-atropine infusion. Sixty-two patients had CAD. Fifty-eight patients (52%) developed minor side effects that resolved promptly. The rate-pressure product (10(3)/mm Hg beats/min) was significantly increased at 12 minutes of infusion (12.4+/-3.2) compared with that at baseline (9.1+/-2.3) and that at 6 minutes of infusion (9.4+/-2.1). The sensitivity for detection of CAD was 45% for AT echocardiography and 74% for AT-atropine echocardiography. The specificity was 94% for AT echocardiography and 90% for AT-atropine echocardiography. The sensitivity and specificity of AT-atropine echocardiography was 78% and 93%, respectively, in group I, and 70% and 86%, respectively, in group II. In conclusion, AT-atropine stress echocardiography seems to be well tolerated, safe, and useful for detection of CAD.