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Biomedical subjects

S Nanto

Publications and source records attributed to S Nanto.

At least 55 records · Page 3Linked to original sources
PubMed1990

[Is emergency angioplasty following successful thrombolysis more effective than thrombolysis alone in acute myocardial infarction?].

This study clarified the effects of residual stenosis following successful thrombolysis in acute myocardial infarction on infarct size and cardiac function in the chronic stage. Subjects consisted of 24 patients with acute anteroseptal myocardial infarction within six hours after the onset of symptoms, in whom thrombolysis was performed, and additional coronary angioplasty was performed in 10 patients. Great cardiac venous flow (GCVF) at a point 30 min after thrombolysis and angioplasty was examined by continuous thermodilution, and the minimal cross-sectional area (MCSA) was determined at a stenotic lesion using an orthogonal angiographic view. As an index of infarct size, we measured abnormally contracting segments (ACS) and perfusion defects (PD) in 201T1 single photon emission computed tomograms four weeks after the onset. We determined anterior regional ejection fraction (rEF) as an index of left ventricular performance in the chronic stage. The patients with thrombolysis alone and the patients with angioplasty were comparable as to age, gender elapsed time, GCVF, MCSA, ACS, PD and rEF. In all the patients, MCSA did not correlate significantly with GCVF. In the patients with additional angioplasty, MCSA significantly increased (from 0.3 +/- 0.3 mm2 to 2.5 +/- 1.6 mm2). However, GCVF did not necessarily increase in all the angioplasty patients. In four patients having delays in angiographic flow, and MCSA less than 0.1 mm2, there was a significant increase in GCVF after angioplasty (41.3 +/- 32.0 vs 82.0 +/- 60.7 ml/min). GCVF correlated significantly with ACS, PD, and rEF, but MCSA did not correlate significantly with them. We concluded that in patients with successful thrombolysis but without angiographic filling delay, emergency angioplasty for residual stenosis has no effect on further limitation of infarct size.

Adult↗
PubMed1989

Right coronary artery occlusion: its role in the mechanism of precordial ST segment depression.

To investigate the mechanism of precordial ST segment depression during right coronary artery occlusion, precordial ST segment shifts and myocardial lactate metabolism were evaluated during coronary angioplasty in 10 patients with (group A) and 7 patients without (group B) precordial ST segment depression during balloon occlusion of the right coronary artery, and in 17 patients with precordial ST segment depression during balloon occlusion of the left anterior descending artery (group C). A 12 lead electrocardiogram was continuously recorded in each patient. Blood lactate in the aorta and great cardiac vein was measured during the procedure, and the lactate extraction ratio in the anterior wall was determined both before and during balloon occlusion. Eight of the 10 patients in group A and 1 of the 7 patients in group B had a dominant large right coronary artery. There were no significant differences in summed ST segment elevation in leads II, III and a VF between group A (0.56 +/- 0.26 mV) and group B (0.46 +/- 0.19 mV) during balloon occlusion of the right coronary artery, and no significant differences in summed ST segment depression in leads V1 to V6 during balloon occlusion between group A (0.44 +/- 0.26 mV) and group C (0.38 +/- 0.14 mV). Lactate extraction ratio before balloon occlusion was similar among the three groups. Patients in group A had a higher lactate extraction ratio during (38 +/- 11%) compared with before (30 +/- 11%) (p less than 0.05) balloon occlusion despite precordial ST segment depression.(ABSTRACT TRUNCATED AT 250 WORDS)

Angina Pectoris↗
PubMed1989

Visualization of subendocardial myocardial ischemia with myocardial contrast echocardiography in humans.

Previous studies indicate the degree of myocardial echo contrast enhancement may be related to regional myocardial perfusion. In this study, myocardial contrast echocardiography was used to characterize changes in the transmural myocardial blood flow distribution that were provoked by rapid atrial pacing in 11 patients with one-vessel coronary artery disease. Ten patients without coronary artery disease served as controls. Myocardial contrast echocardiography was performed by intracoronary injection of 2 ml hand-agitated amidotrizoate sodium meglumine (Urografin-76) and by imaging a short-axis view of the left ventricle with two-dimensional echocardiography before and during injection of the contrast agent. The two-dimensional echocardiographic images at end diastole, before and after injection of the contrast agent, were digitized off-line into a 512 x 512 pixel matrix with 256 gray levels/pixel to quantify the degree of the enhancement of the peak gray level after injection. Transmural myocardial blood flow distribution was evaluated by measuring the ratio of the enhanced gray level in the endocardial half (endo) to that in the epicardial half (epi) (endo:epi gray level ratio) in the anteroseptal, posterolateral, and inferior segments before and just after rapid atrial pacing in each patient. In patients without coronary artery disease, there were no differences in the endo:epi gray level ratio between any of the three segments both before and after pacing. Mean values of the three segments were 0.95 +/- 0.08 before pacing and 0.90 +/- 0.13 after pacing, respectively. In contrast, in patients with coronary artery disease, the endo:epi gray level ratio for the segment supplied with stenotic coronary artery decreased after pacing (0.40 +/- 0.21 vs. 0.93 +/- 0.18, p less than 0.01), probably reflecting subendocardial myocardial ischemia, whereas that for the segment supplied with nonstenotic coronary artery remained unchanged (0.88 +/- 0.20 vs. 0.99 +/- 0.23, NS). Thus, changes in transmural myocardial blood flow distribution with rapid pacing, which may be due to transient subendocardial ischemia, are visualized with myocardial contrast echocardiography.

Adult↗
PubMed1989

[Evaluation of function of human collateral coronary arteries using myocardial contrast echocardiography].

The morphology of collateral vessels can be imaged by coronary angiography, but no method has been available for evaluating their function. This is a report of the use of regional myocardial perfusion to visualize collateral flow by means of myocardial contrast echocardiography in 28 patients with old myocardial infarction. Myocardial contrast echocardiography was accomplished by the intracoronary injection of two ml agitated amidotrizoate sodium meglumine. Short-axis images of the left ventricle were recorded on video tape. Those images were digitized off-line into a 512 x 512 pixel matrix. Using coronary angiography, the morphology and function of the collateral vessels were evaluated, then classified as poor, moderate or good. Myocardial perfusion was evaluated using the enhanced gray level after contrast injection, and the level was compared with the morphology and degree of collateral development. The enhanced gray level was evaluated arbitrarily as 3 +/- 2 U (mean +/- S.D.) in the "poor" group; 13 +/- 6 U in the "moderate" group; and 20 +/- 11 U in the "good" group (p less than 0.01 vs the "poor" group; NS vs the "moderate" group). Regional myocardial perfusion via the collateral vessels was generally proportional to the morphology. However, there were a few discrepancies between these two parameters.

Aged↗
PubMed1989

[Discrepancies between wall motion abnormalities and regional myocardial perfusion in patients with myocardial infarction: evaluation by myocardial contrast echocardiography].

Regional myocardial perfusions obtained by myocardial contrast echocardiography were compared with wall motion abnormalities evaluated by two-dimensional echocardiography in 26 patients with old myocardial infarction (12 with a QS pattern and 14 with a non-QS pattern on electrocardiograms). Myocardial contrast echocardiography was performed by the intracoronary injection of 2 ml of hand-agitated Urografin-76, and short-axis views of the left ventricle were recorded on VTR. Regional myocardial perfusion was categorized using a three-point scale based on the gray levels, and was compared with wall motion abnormalities of the corresponding region as assessed by two-dimensional echocardiography.

Adult↗
PubMed1989

[Serial myocardial lactate metabolic changes after intracoronary thrombolysis in evolving myocardial infarction].

To ascertain whether early intracoronary reperfusion (less than 3 hours) preserves aerobic myocardial metabolism in acute myocardial infarction, serial changes in trans-cardiac lactate extraction after intracoronary thrombolysis were examined in 35 patients with acute anteroseptal myocardial infarction. Eight patients without intracoronary reperfusion served as controls. In the chronic phase, we also observed abnormally contracting myocardial segments as an index of infarct size and the regional ejection fraction as an index of chronic regional cardiac function. In the early reperfusion group (less than 3 hours; 15 cases), positive lactate extraction was restored; there were small abnormally-contracting segments and a high regional ejection fraction. However, the intermediate reperfusion group (3-5 hours; 10 cases) had sustained anaerobic lactate extraction, large abnormally-contracting segments and a low regional ejection fraction. The late reperfusion (greater than 5 hours; 10 cases) group showed apparent aerobic lactate extraction, but had large abnormally-contracting segments and a low regional ejection fraction. Thus, early reperfusion preserves aerobic lactate metabolism and good ventricular function in the chronic phase.

Heart Ventricles↗
PubMed1988

Effects of changes in coronary stenosis on left ventricular diastolic filling assessed with pulsed Doppler echocardiography.

To determine the effects of changes in coronary stenosis on left ventricular diastolic filling, diastolic filling was serially examined before and after percutaneous transluminal coronary angioplasty using pulsed Doppler echocardiography in 50 patients with stable exertional angina pectoris. Peak rapid filling velocity and the ratio of peak atrial filling to peak rapid filling velocities were measured from the transmitral flow velocity pattern before and 2 and 9 days after coronary angioplasty. Peak rapid filling velocity increased and the ratio of peak atrial filling to peak rapid filling velocities decreased gradually after coronary angioplasty. The improvement in left ventricular diastolic filling was greater in patients with severe (greater than 90%) coronary stenosis than in patients with mild (less than or equal to 90%) coronary stenosis. In the long-term follow-up period, the improved left ventricular diastolic filling worsened in only 11 patients with marked progression to greater than 90% coronary stenosis. Thus, left ventricular diastolic filling improved gradually after coronary angioplasty, possibly reflecting post-ischemic "stunned" myocardium. Serial examinations of left ventricular diastolic filling with pulsed Doppler echocardiography may be a means of noninvasively assessing the temporal changes in the coronary stenosis and predicting the occurrence of coronary restenosis after coronary angioplasty.

Adult↗
PubMed1988

Effect of OPC-8212 (2(1H)-quinolinone), a new inotropic agent, on myocardial energy metabolism in patients with coronary heart disease.

We examined the effects of a new inotrope, OPC-8212 (OPC: 2(1H)-quinolinone), on coronary sinus flow (CSF), myocardial oxygen consumption, myocardial lactate extraction ratio (LER), cardiac index (CI) and pulmonary arterial diastolic pressure (PADP) in eleven patients with prior myocardial infarction. Measurements were taken before (control) and 8 hours after administration of OPC (480 mg, p.o.). A cardiac function curve was obtained in each stage with rapid intravenous administration of 500 ml of saline (loaded state) after baseline measurements. There was a significant increase in the cardiac index and decrease in the pulmonary arterial diastolic pressure in the loaded state after OPC. Thus the ventricular function curve was shifted to the left and showed a steep incline, indicating an increased inotropic state. On the other hand, myocardial oxygen consumption and myocardial lactate extraction ratio were unchanged. Thus we concluded that OPC improved cardiac performance without increasing myocardial oxygen consumption.

Adult↗
PubMed1988

[Regional myocardial perfusion in ischemic heart disease assessed by myocardial contrast echocardiography].

Myocardial contrast echocardiography is a new cardiovascular imaging technique that can be used to evaluate regional myocardial perfusion. Regional myocardial perfusion was studied in 12 patients with normal coronary arteries, 14 patients with old myocardial infarction, four patients with acute myocardial infarction, and 15 patients with effort angina. Conventional two-dimensional echo imaging was obtained during intracoronary injections of relatively small volumes (2 ml) of agitated Urografin-76. The echo intensities were measured before and after injecting contrast agents and the subtraction images were composed by a high-speed image processor (NEXUS 6400). Clear myocardial images were obtained in 10 of 12 the patients with normal coronary arteries, and they reflected well the epicardial arterial architecture by coronary angiography. In cases of old myocardial infarction, the infarcted areas appeared as contrast defects in seven and as slightly enhanced areas in three of the 10 patients. In cases of acute myocardial infarction, contrast defect areas in the myocardial images were less in two cases of successful early coronary thrombolysis or percutaneous transluminal coronary angioplasty (PTCA). However, contrast defects remained unchanged despite good recanalization in one case of delayed PTCA. In cases of effort angina, anginal attacks were successfully induced by rapid atrial pacing in six of the 15 patients. In four of the six patients, contrast enhancement in myocardial imaging during anginal attack decreased more in the endocardial than in the epicardial myocardium, possibly reflecting subendocardial ischemia. It is concluded that this technique can identify regional myocardial perfusion, which is not revealed by coronary angiography, and it is therefore useful for the clinical analysis of ischemic heart disease.

Angina Pectoris↗
PubMed1987

Effect of aortocoronary bypass surgery on coronary circulation and myocardial metabolism during atrial pacing.

Eleven patients with coronary heart disease, in whom at least one of several bypass grafts to the left coronary artery was patent, were selected for the study. The hemodynamics, coronary sinus blood flow, myocardial oxygen consumption, and myocardial lactate metabolism were evaluated at rest and during atrial pacing stress test before and after surgery. There were no significant improvements in the cardiac index, pulmonary arterial end-diastolic pressure, and left ventricular ejection fraction after aortocoronary bypass surgery. However, significant improvement of coronary sinus blood flow, myocardial oxygen consumption, and myocardial lactate extraction and consumption were found during postoperative atrial pacing compared with the preoperative findings. These results suggest that successful bypass grafting may improve myocardial lactate metabolism in ischemic lesions and contribute to the postoperative relief of angina.

Cardiac Pacing, Artificial↗
PubMed1987

Acute electrocardiographic changes associated with successful coronary thrombolysis in acute myocardial infarction.

In this study ECG changes were analyzed to assess the acute effects of antegrade blood flow on the ECG in patients with AMI. The study population consisted of 22 patients with MI in whom the totally occluded left anterior descending artery (LAD) or right coronary artery (RCA) was recanalized by intracoronary urokinase infusion (recanalized group) and 14 patients in whom the occluded coronary artery was not successfully recanalized (control group). No significant difference was found in the sum of ST segment elevation (V2-V4 leads for the LAD-occluded group, II, III and aVF leads for the RCA-occluded group) before urokinase infusion. In the recanalized group sigma ST abruptly increased in 5 min after recanalization in 13 of 16 LAD-occluded patients from 1.49 +/- 0.89 mV to 2.44 +/- 1.67 mV (p less than 0.005), and in 4 of 6 RCA-occluded patients from 0.66 +/- 0.12 mV to 1.42 +/- 0.52 mV (p less than 0.01). However increased sigma ST in the recanalized group was reduced to the control value existing before recanalization within 30 min after recanalization and continued to decline more rapidly than in the control group. These transient ST segment elevations were not correlated with long-term angiographic determinants of left ventricular function. We conclude that ST segment shows abrupt augmentation after successful thrombolysis and that continuous ST segment monitoring is useful for assessing thrombolysis in AMI.

Adult↗
PubMed1987

Thromboxane A2 as an enhancing factor of coronary vasospasticity in variant angina.

To clarify the role of thromboxane A2 (TXA2) in evoking coronary spasm, we compared coronary arterial spasticity induced by ergonovine maleate (EM) with coronary sinus thromboxane B2 (TXB2: a stable catabolite of TXA2) in 34 patients with documented variant angina and 11 patients with chest pain syndrome (CPS). We also examined the effect of OKY-1581 (8 mg/kg, i.v.), a TXA2 synthetase inhibitor, on the coronary arterial spasticity of these patients. When blood samples were taken from coronary sinus just before EM test, all patients with variant angina exhibiting markedly augmented TXB2 levels (424 +/- 138 pg/ml), had positive EM test results, while CPS exhibiting lower TXB2 levels (223 +/- 38 pg/ml), had negative EM test. We found that the amounts of EM needed to induce coronary spasm were inversely correlated with TXB2 levels in coronary sinus. In 7 out of these 8 patients, OKY-1581 was found to attenuate the increased spasticity with reduction of coronary sinus TXB2 levels. In 3 patients, an EM rechallenge at symptomatically quiescent stage resulted in negative test with augmented TXB2 levels being markedly decreased. These findings indicate that increased TXA2 in circulating plasma is closely correlated with the hypersensitivity of coronary arteries to EM in patients with variant angina, suggesting a possible role of augmented TXA2 production in the enhancement of coronary vascular spasticity.

Adult↗
PubMed1986

Oral OPC-8212 for the treatment of congestive heart failure: hemodynamic improvement and increased exercise capacity.

The chronic effects of the oral administration of OPC-8212 (3,4-dihydro-6-[4-(3,4-dimethoxybenzoyl)-1-piperazinyl]-2(1H)-quinolinon e) on resting hemodynamics and exercise capacity were assessed in 15 patients with congestive heart failure (NYHA II-IV). Doses of 30 or 60 mg per day were given per os over 3.0 weeks on average (range 2-6 weeks). Multigated radionuclide ventriculography and multistage exercise testing were performed before and during OPC-8212 therapy to assess the changes in left ventricular volume and exercise capacity respectively. Systolic blood pressure showed a slight increase (from 123 +/- 3 to 129 +/- 4 mmHg) during OPC-8212 therapy, while heart rate was unchanged (69 +/- 3 vs 67 +/- 3 beats/min). The left ventricular end-diastolic volume index decreased from 127 +/- 9 to 107 +/- 7 ml/m2, and ejection fraction and the P/V index (the ratio of peak systolic pressure to left ventricular end-systolic volume index) increased during OPC-8212 therapy (from 27% +/- 3% to 30% +/- 4% and from 1.5 +/- 0.2 to 2.0 +/- 0.3 mmHg/ml/m2 respectively). NYHA functional class was improved in 9 of 15 patients, and the average peak work load achieved during exercise testing increased from 27 +/- 6 to 47 +/- 7 W. No significant adverse effect was observed in any patient. These results indicate that OPC-8212 enhances the inotropic state and, hence, reduces heart size with no change in heart rate. Moreover, it increases exercise capacity. Thus, OPC-8212 is an inotropic agent with promise for application in the long-term treatment of congestive heart failure.

Administration, Oral↗
PubMed1986

Clinical assessment of elastic properties of large coronary arteries: pressure-diameter relationship and dynamic incremental elastic modulus.

Vascular elastic properties in vivo (dynamic incremental elastic modulus [Ep(dyn)]) of large coronary arteries were assessed from the pressure-diameter relationships of the large coronary arteries in 46 patients with suspected ischemic heart disease. Ep(dyn) represents the vascular stiffness primarily determined by the organic sclerotic changes of the vascular wall and the vascular smooth muscle tone. Coronary arterial diameter was obtained from the magnified cine coronary arteriograms by using a computerized caliber measurement technique. The mean Ep(dyn) of the left main coronary artery and the proximal portions of the left anterior descending and circumflex coronary arteries with apparently normal angiograms were significantly (P less than 0.01) increased as the number of involved coronary vessels was increased. Mean Ep(dyn) values in multi-vessel disease were comparable with those of dilated segment by the percutaneous transluminal coronary angioplasty, indicating that the vascular sclerotic changes are not localized to the narrowed segments but diffusely distributed to the angiographically normal vascular wall. In 4 patients who had successful percutaneous transluminal coronary angioplasty, Ep(dyn) of the dilated coronary segment showed markedly higher values (0.21-0.30 X 10(6) Nm-2) than the normal values (0.16 +/- 0.06 X 10(6) Nm-2 in left anterior descending coronary artery). In contrast, there was no significant difference in Ep(dyn) values of the angiographically normal left main coronary trunk, proximal portions of left anterior descending and circumflex arteries between patients with and without vasospastic angina. During myocardial ischemia induced by ergonovine maleate, vasospastic response of the non-diseased segment was comparable with that in patients who did not have an anginal attack during the ergonovine test. Thus, in contrast to the sclerotic change, abnormal vasoconstrictive property of the coronary artery may be localized to the diseased segment.

Adult↗