Assessment of regional and global left ventricular function by reinjection T1-201 and rest Tc-99m sestamibi ECG-gated SPECT: comparison with three-dimensional magnetic resonance imaging.

OBJECTIVES: The purpose of this study was to test the ability of reinjection thallium-201 and rest technetium-99m sestamibi ECG (electrocardiographic)-gated SPECT (i.e., reinjection-g-SPECT [single-photon emission computed tomography] and MIBI-g-SPECT) to determine regional and global functional parameters. BACKGROUND: The ECG-gated perfusion SPECT was reported to provide accurate left ventricular ejection fraction (LVEF) using an automated algorithm. We hypothesized that other various functional data may be obtained using reinjection-g-SPECT and MIBI-g-SPECT. METHODS: Reinjection-g-SPECT, MIBI-g-SPECT, and three-dimensional magnetic resonance imaging (3DMRI) were conducted in 20 patients with coronary artery disease. Regional wall motion (RWM) and wall thickening (RWT) were analyzed using semiquantitative visual scoring by each g-SPECT and 3DMRI. The left ventricular end-systolic and end-diastolic volumes (EDV, ESV) and LVEF estimated by reinjection- and MIBI-g-SPECT were compared with the results of 3DMRI. RESULTS: A high degree of agreement in RWM and RWT assessment was observed between each g-SPECT and 3DMRI (kappa >.70, p < .001). The LVEF values by reinjection- and MIBI-g-SPECT correlated and agreed well with those by 3DMRI (reinjection: r = .92, SEE = 5.9%, SD of differences = 5.7%; sestamibi: r = .94, SEE = 4.4%, SD of differences = 5.1%). The same also pertained to EDV (reinjection: r = .85, SEE = 18.7 ml, SD of differences = 18.4 ml; sestamibi: r = .92, SEE = 13.1 ml, SD of differences = 13.0 ml) and ESV (reinjection: r = .94, SEE = 10.3 ml, SD of differences = 10.3 ml; sestamibi: r = .97, SEE = 6.7 ml [p < .05 vs. reinjection by F test], SD of differences = 6.6 ml [p < .05 vs. reinjection by F test]). CONCLUSIONS: Reinjection- and MIBI-g-SPECT provide clinically satisfactory various functional data. These functional data in combination with the perfusion information will improve diagnostic and prognostic accuracy without an increase in cost or the radiation dose to the patients.

Simultaneous assessment of myocardial free fatty acid utilization and left ventricular function using 123I-BMIPP-gated SPECT.

UNLABELLED: This study was designed to evaluate the methodological feasibility of 123I-labeled beta-methyl-p-iodophenyl-pentadecanoic acid (BMIPP)-gated SPECT to assess regional and global left ventricular (LV) function in comparison with 99mTc-sestamibi (methoxyisobutyl isonitrile [MIBI])-gated SPECT and first-pass radionuclide angiography (FPRNA). METHODS: Forty-four patients with stable coronary artery disease underwent rest BMIPP-gated SPECT (111 MBq, 60 s/step) and rest MIBI-gated SPECT (600 MBq, 40 s/step) within a week. From both gated SPECT studies, regional defect scores (DS), wall motion scores (WMS) and wall-thickening scores (WTS) were evaluated visually using 4-point scales for nine segments, and LV ejection fraction (EF) (%) was automatically calculated using Quantitative Gated SPECT (QGS) software. FPRNA was also performed on injection of MIBI. RESULTS: Exact agreement between the two gated SPECT studies was 84.1% (kappa = 0.706, r = 0.907, P < 0.0001) in WMS and 87.1% (kappa = 0.662, r = 0.884, P < 0.0001) in WTS. LVEF obtained from BMIPP-gated SPECT linearly correlated with those from MIBI-gated SPECT (y = -0.27 + 0.944x, r = 0.948, SEE = 5.00, P < 0.0001) and FPRNA (y = -7.32 + 1.042x, r = 0.919, SEE = 6.19, P < 0.0001). Even in 21 patients with mismatch segments (BMIPP DS > MIBI DS), agreement was considered to be acceptable in WMS (81.5%, kappa = 0.707, r = 0.853, P < 0.0001) and in WTS (76.7%, kappa = 0.526, r = 0.754, P < 0.0001), and correlation in LVEF remained good between BMIPP-gated SPECT and MIBI-gated SPECT (y = -1.24 + 0.955x, r = 0.938, SEE = 6.25, P < 0.0001) or FPRNA (y = -6.03 + 1.024x, r = 0.913, SEE = 7.38, P < 0.0001). CONCLUSION: BMIPP-gated SPECT can evaluate regional and global LV function with the QGS software. Therefore, BMIPP-gated SPECT offers the opportunity for simultaneous assessment of myocardial free fatty acid utilization and LV function.

Evaluation of a compressive-type skeletal muscle pump for cardiac assistance.

BACKGROUND: Recent investigations have focused on using the latissimus dorsi muscle for cardiac assistance. Although cardiomyoplasty has been applied clinically, other procedures remain experimental, but promising, modes of cardiac assistance. We assessed the latissimus dorsi muscle as an in situ energy source for circulatory assist devices. METHODS: We developed a pneumatic chamber as a compressive-type muscle actuator. The chamber was implanted under the latissimus dorsi muscle and converted contractile power into pneumatic pressure. The effect of chamber position and size and the influence on muscle blood flow were examined. After muscle conditioning, the pump performance of a circulatory assist device driven by the chamber was evaluated. RESULTS: The chamber functioned better when placed in the proximal position of the latissimus dorsi muscle. The size affected the generated pneumatic pressure, and the higher resting pressure of the chamber reduced the muscle blood flow. The maximum stroke work of the circulatory assist device was greater than that of the right ventricle but less than that of the left ventricle. The chamber could drive the circulatory assist device against the systemic range of afterload in which a high preload was available. Long-term adhesion surrounding the chamber reduced the pressure generation capability. CONCLUSIONS: The compressive-type muscle actuator using the latissimus dorsi muscle generated acceptable hemodynamic work for right ventricular bypass or aortic counterpulsation.

Surgical repair of coronary arteriovenous fistula: a simple and useful approach to identify the fistulous communication.

In repairing coronary arteriovenous fistula (CAVF), it is very important to interrupt the fistulous tract without compromise of normal coronary vessel flow. In our case, selective coronary arteriography showed that the CAVF from the left anterior descending coronary artery (LAD) was very close to the native coronary artery and had a very broad and short neck. We describe a simple and useful approach, by using both antegrade and retrograde coronary perfusion, that makes it possible to certainly protect myocardium and to clearly distinguish the normal native coronary artery from the fistulous tract.

Applicability of the latissimus dorsi muscle in situ as a biomechanical energy source.

The purpose of this study was to assess the applicability of the latissimus dorsi muscle in situ as an energy source for a circulatory assist device. A pneumatic chamber, devised by the authors, was inserted beneath the muscle and compressed by contractions of the muscle so that muscle contractile power was converted into pneumatic pressure. The optimal insertion position of the chamber beneath the latissimus dorsi muscle, and the influence of chamber size on generated pneumatic pressure, were investigated. The pneumatic chamber functioned better when it was placed in a proximal position (third intercostal space) than in a middle or distal position. Using a mock circuit, the performance of the pneumatic chamber as an energy source for a circulatory assist device was evaluated. The pneumatic chamber was able to generate power sufficient to drive a right ventricular assist device as far as stroke work was involved. When the pneumatic chamber was operated with a high afterload, it could even be an energy source for aortic counterpulsation.

A compressive type skeletal muscle pump as a biomechanical energy source.

The purpose of this study was to assess the applicability of the conditioned latissimus dorsi muscle as an energy source for circulatory assist devices. The authors developed a pneumatic chamber as a muscle actuator. The pneumatic chamber placed between latissimus dorsi muscle and chest wall was compressed by the burst stimulated muscle and, thereby, converted muscle contractile power into pneumatic pressure. The authors report the performance of the implanted pneumatic chamber at a chronic phase, and the capability of the conditioned muscle in situ as an energy source for circulatory assist devices. Six adult mongrel dogs were used. At the first operation, a pacemaker for muscle conditioning and the pneumatic chamber were implanted. After 12 weeks of muscle conditioning, the performance of the pneumatic chamber with conditioned muscle was evaluated. The pressure generating capability of a chamber buried in fibrous adhesions was reduced to approximately 65% of that of a chamber without adhesions. The stroke volume and stroke work of the assist device driven by the developed pneumatic pressure were measured. The maximum stroke work of the circulatory assist was greater than the stroke work of the right ventricle, but less than that of the left ventricle. In respect to stroke volume, the pneumatic chamber could drive the circulatory assist device against not only a pulmonary range of afterload, but also a systemic range of afterload, when high pre load was available. These results indicate that the compressive skeletal muscle pump with conditioned latissimus dorsi muscle generates acceptable hemodynamic work for right ventricular bypass or aortic counterpulsation. In the long-term, the interface between tissue and actuator is the major obstacle to developing a muscle powered assist device.

Variations of wood delta(13)C for the past 50 years in declining Siebold's beech (Fagus crenata) forests.

Markedly damaged stands have been observed in Siebold's beech (Fagus crenata) forests on the Tanzawa Mountains, Japan, which are located close to densely populated and heavily industrial areas. We measured the delta(13)C records for the past 50 years (1944-1997) in wood cellulose sampled from relatively healthy trees in declining forests on Mt. Hinokiboramaru (1600 m). This may provide information on the history of stresses related to environmental changes, which have caused the decline symptoms. The results showed that, for all of the trees studied, wood delta(13)C has decreased with time. Also, the difference in delta(13)C among trees grew abruptly after the mid-1960s, which almost coincides with the time when the decline symptoms were markedly observed. Some trees with large reduction of wood delta(13)C exhibited the strong decreases in radial growth. This suggests that the reduction of tree growth may have been more greatly influenced by decreasing carboxylation rate than by stomatal limitation. It is unlikely that water stress and SO(2) and O(3) stresses have induced the growth reduction, because those stresses cause increasing wood delta(13)C. This is supported by the facts that wet conditions and relatively low SO(2) and O(3) levels have been observed near Mt. Hinokiboramaru. In addition, analyses of wood Ca showed no evidence that acid fog and soil acidification have affected the wood delta(13)C and growth through effects on the nutrient uptake of trees. However, what type of stresses have induced the large reduction of wood delta(13)C and growth for some of the trees studied remains unknown because of the lack of sufficient data for evaluation. In contrast, lesser reduction of wood delta(13)C from the other trees may be related to an increase in the plant water-use efficiency with increasing atmospheric CO(2) concentration.

Circulatory arrest with profound hypothermia during the surgical treatment of large internal carotid artery aneurysm--case report.

A 43-year-old male presented with a cerebral aneurysm manifesting as right facial paresthesia, without neurological deficit. Angiography revealed a large aneurysm (22 mm) of the left internal carotid artery. Intravascular treatment using placement of a detachable coil was attempted, but the coil did not stay in the aneurysmal cavity and the procedure was abandoned. The patient did not tolerate the transient balloon occlusion test of the left internal carotid artery. Therefore, the aneurysm was clipped through an open craniotomy with profound hypothermia (20 degrees C) with cardiac arrest (24 minutes). The aneurysmal dome was collapsed, allowing easy dissection of the posterior communicating artery. The closed chest method was used during the extracorporeal cardiopulmonary bypass. Postoperative angiography revealed complete neck clipping with preservation of carotid blood flow. The patient recovered well and resumed his employment. Circulatory arrest with hypothermia provides several benefits for the surgical treatment of large and giant aneurysms.

Aortoesophageal fistula caused by foreign body.

Aortoesophageal fistula is rare. A woman who developed aortoesophageal fistula after swallowing a fish bone developed hematemesis. 7 days later, we resected a false aneurysm near the left subclavian artery and repaired this section twice. Despite these measures, the woman died on hospital day 21. The clinical diagnosis was massive hematemesis from an infected aortic wall. The method of diagnosis, control of infection, and operative repair of aortoesophageal fistula are discussed.

[Surgical results of valvular heart disease combined with myocardial revascularization].

Risk factors for hospital death after combined valvular and coronary artery bypass surgery were examined in 131 consecutive cases between October 1988 and December 1999. These accounted for 8.0% of all 1,644 cases of coronary revascularization surgery and 15.3% of all 854 cases of valvular heart disease surgery. 84 men and 43 women underwent combined valvular and coronary artery bypass surgery. The mean age of the patients was 68.9 +/- 3.9 (22-86) years old. Numbers of cases comprised 58 undergoing aortic valve surgery, 63 undergoing mitral valve surgery, and 10 undergoing eight patients died during hospitalization after the operation: four due to cardiac death and four due to non-cardiac death. We studied pre- and perioperative risk factors for hospital death by means of multivariate analysis. As the major factors, ischemic mitral regurgitation, chronic renal failure, and duration of cardiopulmonary bypass were identified as three major predictors of hospital death. Ischemic mitral regurgitation was the strong predictor (p = 0.03) with 5 hospital deaths out of 38 ischemic mitral regurgitation cases (13.1%), whereas only 3 hospital deaths were seen in 93 other cases (3.2%) operated on in the same period. Over all operation results were not unfavorable, indicating that combined operations may be electively performed if severe coronary artery disease was present. The surgical results with ischemic mitral regurgitation are as yet not well documented and will require further study.

[A successful surgical repair of total anomalous pulmonary venous connection associated with Williams syndrome].

The surgical correction was performed successfully in a 14-year-old boy with total anomalous pulmonary venous connection (type Ia) associated with Williams syndrome. The diagnosis was made at the age of 3 and he had been well until the age of 13 when sudden chordal rupture caused severe mitral regurgitation and supraventricular tachyarrhythmia. The operational procedure includes common pulmonary vein and left atrium anastomosis through Gersony-Malm approach, chordal reconstruction of mitral valve with 4-0 Core Tex sutures. His postoperative course has been well without the sign of venous obstruction. As far as we know, this is the first documentation of a case of Williams syndrome associated with total anomalous pulmonary venous connection.

[A successful case of minimally invasive direct coronary artery bypass (MIDCAB) followed by PTCA].

A 70-year-old man who developed angina pectoris underwent cardiac catheterization, which showed total occlusion of the left anterior descending coronary artery (LAD), associated with 75% stenosis of the right coronary artery (RCA) and 90% stenosis of the small circumflex coronary artery (CX). The LAD received good collateral flow from the RCA. The patient was scheduled to undergo the MIDCAB for the LAD using the internal thoracic artery (ITA), combined with percutaneous transluminal coronary angioplasty (PTCA) for the RCA subsequently. A left anterior submammarian skin incision of 10 cm in length was made. The fifth costal cartilage was removed. The left ITA was directly harvested from the chest wall from the 4th to 7th intercostal space, and was anastomosed to the midportion of the LAD without cardiopulmonary bypass. The patient was quickly recovered after the operation. On the 8th postoperative day, the patient successfully underwent the PTCA for the RCA after the ITA-LAD graft had been verified to be patent. The MIDCAB could be indicated for multivessel coronary disease in conjunction with the PTCA.

Regional quantification of muscarinic acetylcholine receptors and ß-adrenoceptors in human airways.

BACKGROUND AND PURPOSE Muscarinic acetylcholine receptors (mAChRs) and ß-adrenoceptors in the airways and lungs are clinically important in chronic obstructive pulmonary disease (COPD) and asthma. However, the quantitative and qualitative estimation of these receptors by radioligand binding approaches in human airways has not yet been reported because of tissue limitations. EXPERIMENTAL APPROACH The regional distribution and relative proportion of mAChR and ß-adrenoceptor subtypes were evaluated in human bronchus and lung parenchyma by a tissue segment binding method with [(3)H]-N-methylscopolamine ([(3)H]-NMS) for mAChRs and [(3)H]-CGP-12,177 for ß-adrenoceptors. Functional responses to carbachol and isoprenaline were also analysed in the bronchus. KEY RESULTS The M(3) subtype predominantly occurred in the bronchus, but the density decreased from the segmental to subsegmental bronchus, and was absent in lung parenchyma. On the other hand, the M(1) subtype occurred in the lung only, and the M(2) subtype was distributed ubiquitously in the bronchus and lungs. ß(2)-adrenoceptors were increased along the airways, and their densities in the subsegmental bronchus and lung parenchyma were approximately twofold higher than those of mAChRs in the same region. ß(1)-adrenoceptors were also detected in lung parenchyma but not in the bronchus. The muscarinic contractions and adrenoceptor relaxations in both bronchial regions were mediated through M(3)-mAChRs and ß(2)-adrenoceptors, respectively. CONCLUSIONS AND IMPLICATIONS From the present radioligand binding approach with intact tissue segments, we constructed a distribution map of mAChRs and ß-adrenoceptors in human bronchus and lung parenchyma for the first time, providing important evidence for future pharmacotherapy and new drug development for respiratory disorders.

Use of technetium-99m sestamibi ECG-gated single-photon emission tomography for the evaluation of left ventricular function following coronary artery bypass graft: comparison with three-dimensional magnetic resonance imaging.

In patients who had undergone cardiac surgery (coronary artery bypass graft) and whose hearts showed abnormal movement during the cardiac cycle, we studied the accuracy of functional assessment using ECG-gated single-photon emission tomography (SPET) and the automated software developed by Germano et al. by comparing the findings with magnetic resonance (MR) images acquired three-dimensionally. Sixteen patients who had undergone cardiac surgery underwent 99mTc-sestamibi gated SPET (MIBI-g-SPET) and MRI on the same day. Left ventricular end-diastolic and end-systolic volumes (EDV, ESV) and ejection fraction (LVEF) were measured using MIBI-g-SPET and the aforementioned algorithm. Regional wall thickening was assessed using a four-point scale on MIBI-g-SPET and cine MRI. There was a good correlation between MIBI-g-SPET and MRI in respect of EDV (r=0.89), ESV (r=0.93) and LVEF (r=0.89). A high degree of agreement was found between the wall thickening scores obtained by MIBI-g-SPET and MRI in total segments (kappa=0.62) and in septal segments (kappa=0.67). It is concluded that ECG-gated perfusion SPET can provide regional and global functional information, including absolute volumes, in patients following cardiac surgery.

Assessment of the effect of revascularization early after CABG using ECG-gated perfusion single-photon emission tomography.

When an arterial graft is used, reversible perfusion defects on single-photon emission tomography (SPET) perfusion images are occasionally observed early after coronary artery bypass graft surgery (CABG), owing to the restricted flow capacity. The purpose of this study was to determine whether the functional information obtained with electrocardiography (ECG)-gated perfusion SPET could be helpful in evaluating the effect of revascularization early after CABG. Twenty-three patients (18 men and 5 women, mean age 65+/-9 years) underwent stress/re-injection thallium-201 ECG-gated SPET before and 4 weeks after CABG (13 with exercise and 10 with dipyridamole). Patency of all grafts was confirmed by coronary angiography 1 month after CABG. Cardiac functional data including the left ventricular ejection fraction (LVEF) and the transient ischaemic dilatation (TID) ratio were analysed using a commercially available automated program. The conventional stress and re-injection tomograms were interpreted by means of a five-point scoring system in a nine-segment model. Stress-induced reversible 201Tl perfusion defects were present in 64% of the myocardial segments bypassed by patent arterial grafts, in contrast to 42% of the myocardial segments bypassed by patent venous grafts (chi2=7.8, P=0.005). Of the 23 patients, 12 showed improvement in summed ischaemic scores (group 1), while 11 had no change or deterioration (group 2), although all grafts were patent on postoperative catheterization. The TID ratio improved in both group 1 and group 2 before and after CABG (1.14+/-0.13 vs 0.99+/-0.07, P=0.001 and 1.09+/-0.07 vs 0.94+/-0.05, P=0.002, respectively). However, LVEF did not significantly improve in group 1 or group 2 after CABG (42.5%+/-9.9% vs 47.5%+/-11.8%, and 52.1%+/-7.5% vs 53.1%+/-5.9%, respectively). Perfusion imaging or LVEF assessment is of limited value early after CABG. The TID ratio obtained with ECG-gated perfusion SPET may be a useful marker to evaluate the effect of revascularization early after surgery.