Impact of wall shear stress affected by anatomical difference between acute and chronic coronary syndrome in patients with LAD proximal disease

 

Recent hemodynamic studies have demonstrated that progression of coronary atherosclerosis occurs at low wall share-stress site, whereas plaque rupture frequently occurs at high share stress site. It is well recognized that wall shear stress is relatively low along the outer walls of the bifurcation.

We investigated consecutive 140 patients (77 with acute coronary syndrome (ACS) and 63 with chronic coronary syndrome (CCS) performed PCI for LAD proximal lesions (AHA seg.6) from January 2016 to December 2019. In CCS group, entry criteria included stenosis of at least 90% in the LAD proximal lesion or at least 70% in the LAD proximal lesion and objective evidence of myocardial ischemia (inducible ischemia with either exercise or pharmacologic vasodilator stress or with pressure wire). Exclusion criteria were patients with maintenance dialysis, chronic total occlusion lesions, in-stent restenosis, and clinically diagnosed unstable angina without troponin I elevation. We measured the distance from LMT distal carina to the culprit site (Distance) and plaque location (Location) with intravascular ultrasound and angle between LMT and LAD with cardiovascular angiography analysis system (CAAS) (Angle).

The two groups were generally well balanced with regard to baseline clinical characteristics. The mean (±SD) age of the patients was 69.0±11.8 years, and 75% were men. Medication at baseline was also similar between two groups except higher prevalence of statin prescription in CCS group. The Distance was shorter and Angle was steeper in CCS group than in ACS group. The number of patients with Angle less than 150 degrees and with Location in the lateral wall side was much more in CCS group.

In this study, plaques in CCS were frequently observed at low shear stress site, whereas those in ACS at high shear stress site. Plaque progression in CCS may be associated with low wall shear stress, and high shear stress may play key role in plaque rupture in ACS. This anatomical difference can partly explain the different mechanisms of onset between of ACS and CCS.

Funding Acknowledgement

Type of funding sources: None. Anatomical differenceCharacteristics and results

Efficacy of Complex Fractionated Atrial Electrogram-Guided Extensive Encircling Pulmonary Vein Isolation for Persistent Atrial Fibrillation

Background: In persistent AF, the effect of adjunctive ablation in addition to PV isolation (PVI) is controversial. We considered a new modified PVI including complex fractionated atrial electrogram (CFAE) area.

Methods and Results: In 57 patients with persistent AF undergoing first ablation, CFAE were mapped before ablation and CFAE-guided extensive encircling PVI (CFAE-guided EEPVI) was performed. The PVI line was designed to include the CFAE area near PV or to cross the minimum cycle length points of the CFAE area near PV (CFAE-guided EEPVI group). The outcome was compared with conventional PVI in 34 patients with persistent AF (conventional PVI group). During a mean follow-up of 365±230 days after the first procedure, AF in 13 and atrial tachycardia (AT) in 9 patients recurred in the CFAE-guided EEPVI group, while only AF in 17 patients recurred in the conventional PVI group. Eight of 9 AT in the CFAE-guided EEPVI group were successfully ablated at second procedure. After first and second procedures, the recurrence of atrial tachyarrhythmia in the CFAE-guided EEPVI group was significantly reduced compared with the conventional PVI group (8 patients, 14% vs. 11 patients, 32%, respectively; P<0.01, log-rank test).

Conclusions: CFAE-guided EEPVI was more effective for persistent AF compared with conventional PVI after first and second procedures, because recurring AT as well as re-conduction of PV was successfully ablated.

The ReACT Trial: Randomized Evaluation of Routine Follow-up Coronary Angiography After Percutaneous Coronary Intervention Trial

OBJECTIVES

The purpose of this study was to evaluate long-term clinical impact of routine follow-up coronary angiography (FUCAG) after percutaneous coronary intervention (PCI) in daily clinical practice in Japan.

BACKGROUND

The long-term clinical impact of routine FUCAG after PCI in real-world clinical practice has not been evaluated adequately.

METHODS

In this prospective, multicenter, open-label, randomized trial, patients who underwent successful PCI were randomly assigned to routine angiographic follow-up (AF) group, in which patients were to receive FUCAG at 8 to 12 months after PCI, or clinical follow-up alone (CF) group. The primary endpoint was defined as a composite of death, myocardial infarction, stroke, emergency hospitalization for acute coronary syndrome, or hospitalization for heart failure over a minimum of 1.5 years follow-up.

RESULTS

Between May 2010 and July 2014, 700 patients were enrolled in the trial among 22 participating centers and were randomly assigned to the AF group (n = 349) or the CF group (n = 351). During a median of 4.6 years of follow-up (interquartile range [IQR]: 3.1 to 5.2 years), the cumulative 5-year incidence of the primary endpoint was 22.4% in the AF group and 24.7% in the CF group (hazard ratio: 0.94; 95% confidence interval: 0.67 to 1.31; p = 0.70). Any coronary revascularization within the first year was more frequently performed in AF group than in CF group (12.8% vs. 3.8%; log-rank p < 0.001), although the difference between the 2 groups attenuated over time with a similar cumulative 5-year incidence (19.6% vs. 18.1%; log-rank p = 0.92).

CONCLUSIONS

No clinical benefits were observed for routine FUCAG after PCI and early coronary revascularization rates were increased within routine FUCAG strategy in the current trial. (Randomized Evaluation of Routine Follow-up Coronary Angiography After Percutaneous Coronary Intervention Trial [ReACT]; NCT01123291).

Computer-Aided Interpretation of Coronary Cineangiograms

To accurately diagnose stenotic lesions on coronary cineangiograms, an automatic detection method using computer image processing was developed. We evaluated its accuracy by comparing the results of computer-aided interpretation (CAI) with those obtained independently by 3 observers. Evaluation was performed on 129 segments from 27 arteries visualized on angiograms obtained in 18 patients. The detection rates of stenosis of the 3 observers by pure visual interpretation were 7.0%, 27.9%, and 17.1%, and using CAI 40.0%, 42.6%, and 47.3%. By computer recognition alone, a detection rate of 51.9% was achieved. The agreement by at least 2 observers (consensus) on the sites with lesions was 41.1% while the consensus of computer recognition regarding the sites with lesion was 40.3%. Therefore, our findings indicated that computer recognition of cineangiograms is likely to result in overdetection of lesions. However, all 3 observers detected stenotic lesions better with CAI than with pure visual interpretation. Accordingly, CAI may improve the reliability of cineangiographic diagnosis.

Impact of NAD(P)H Oxidase-Derived Reactive Oxygen Species on Coronary Arterial Remodeling

Background— Coronary arterial remodeling, which is a response to the growth of atherosclerotic plaques, is associated with plaque vulnerability. Oxidative stress induced by reactive oxygen species (ROS) via NAD(P)H oxidase in the vasculature also plays a crucial role in the pathogenesis of atherosclerosis-based cardiovascular disease. In this study, the relationship between coronary arterial remodeling and ROS generation was examined by comparing preinterventional intravascular ultrasound findings of atherosclerotic lesions to the histochemical findings of corresponding specimens obtained by directional coronary atherectomy.

Methods and Results— Predirectional coronary atherectomy intravascular ultrasound images of 49 patients were analyzed. The remodeling index was calculated by dividing the target-lesion external elastic membrane cross-sectional area by the reference-segment external elastic membrane cross-sectional area. Expansive remodeling was defined as a remodeling index of >1.0. ROS generation and NAD(P)H oxidase p22 phox expression in directional coronary atherectomy specimens were evaluated using the dihydroethidium staining method and immunohistochemistry as the ratio of the positive area to the total surface area in each specimen, respectively. ROS generation and p22 phox expression were significantly greater in lesions with expansive remodeling than in lesions without remodeling (0.18�0.12 versus 0.03�0.02, P <0.0001, 0.10�0.08 versus 0.04�0.05, P =0.0039, respectively). Both ROS generation and p22 phox expression significantly correlated with the intravascular ultrasound-derived remodeling index ( r =0.77, P <0.0001, r =0.53, P <0.0001, respectively).

Conclusions— Simultaneous examination with intravascular ultrasound and immunohistochemistry analyses suggests that NAD(P)H oxidase-derived ROS is related to the coronary arterial remodeling process associated with plaque vulnerability.

Effect of culprit-lesion remodeling versus plaque rupture on three-year outcome in patients with acute coronary syndrome

To investigate intravascular ultrasound predictors of long-term clinical outcome in patients with acute coronary syndrome, 94 patients with a first acute coronary syndrome with both preintervention intravascular ultrasound imaging and long-term follow-up were enrolled in this study. Remodeling index was defined as external elastic membrane cross-sectional area at the target lesion divided by that at the proximal reference. Arterial remodeling was defined as either positive (PR: remodeling index >1.05) or intermediate/negative remodeling (remodeling index < or =1.05). Clinical events were death, myocardial infarction, and target-lesion revascularization. Patients were followed up for a mean of 3 years. PR was observed in 50 (53%), and intermediate/negative remodeling, in 44 (47%). During the 3-year follow-up, there were 20 target-lesion revascularization events and 5 deaths (2 cardiac and 3 noncardiac), but no myocardial infarctions. Patients with PR showed significantly lower major adverse cardiac event (MACE; death, myocardial infarction, and target-lesion revascularization)-free survival (log-rank p = 0.03). However, patients with plaque rupture showed a nonsignificant trend toward lower MACE-free survival (p = 0.13), but there were no significant differences in MACE-free survival between those with single versus multiple plaque ruptures. Using multivariate logistic regression analysis, only culprit lesion PR was an independent predictor of MACEs (p = 0.04). In conclusion, culprit-lesion remodeling rather than the presence or absence of culprit-lesion plaque rupture was a strong predictor of long-term (3-year) clinical outcome in patients with acute coronary syndrome.

Impact of Cutting Balloon Angioplasty (CBA) Prior to Bare Metal Stenting on Restenosis A Prospective Randomized Multicenter Trial Comparing CBA With Balloon Angioplasty (BA) Before Stenting (REDUCE III)

BACKGROUND

While stent restenosis and late thrombosis still occur even with drug-eluting-stents (DES), there remains a need to explore other strategies for preventing restenosis.

METHODS AND RESULTS

Five hundred and twenty-one patients were randomized: 260 to cutting-balloon angioplasty (CBA) before bare-metal stent (CBA-BMS) and 261 to balloon-angioplasty (BA) before BMS (BA-BMS). Intravascular ultrasound (IVUS)-guided procedures were performed in 279 (54%) patients and angiographic guidance was used in the remainder. Minimal lumen diameter was significantly greater in CBA-BMS than BA-BMS (2.65+/-0.40 mm vs 2.52+/-0.4 mm, p<0.01) and % diameter stenosis (%DS)-post was less in CBA-BMS than BA-BMS (14.0+/-5.9% vs 16.3+/-6.8%, p<0.01). %DS-follow-up was subsequently less in CBA-BMS than BA-BMS (32.4+/-15.1% vs 35.4+/-15.3%, p<0.05) associated with lower rates of restenosis in CBA-BMS than BA-BMS (11.8% vs 19.6%, p<0.05) and less target lesion revascularization (TLR) in CBA-BMS than BA-BMS (9.6% vs 15.3%, p<0.05). Patients were divided into 4 groups based on the device used before stenting and IVUS use (IVUS-CBA-BMS: 137 patients; Angio-CBA-BMS: 123; IVUS-BA-BMS: 142; and Angio-BA-BMS: 119). At follow-up IVUS-CBA-BMS had a significantly lower restenosis rate (6.6%) than Angio-CBA-BMS (17.9%), IVUS-BA-BMS (19.8%) and Angio-BA-BMS (18.2%, p<0.05).

CONCLUSIONS

Restenosis and TLR were significantly lower in CBA-BMS than BA-BMS. This favorable outcome was achieved because of the lower restenosis rate conferred by the IVUS-guided-CBA-BMS strategy (6.6%). The restenosis rates obtained with this strategy were comparable to those achieved with DES.

Soluble CD40 ligand and interleukin-6 in the coronary circulation after acute myocardial infarction

BACKGROUND

Inflammation, operated by blood, vascular and immune cells interaction, is implicated in plaque disruption and CD40 ligand (CD40L) was identified on activated T cells and platelets. We sought to investigate the roles of local inflammation in acute myocardial infarction (AMI).

METHODS

Coronary sinus (CS) and arterial (A) levels of interleukin (IL)-6 and soluble CD40L (sCD40L) and matrix metalloproteinase (MMP)-9 activity in serial blood samples obtained until 48 h after percutaneous coronary intervention (PCI) were determined. In tissue specimens obtained by aspirating thrombectomy and directional coronary atherectomy, CD40L was immunohistochemically stained.

RESULTS

Trans-cardiac gradient (CS-A) of IL-6, indicating cardiac release into the coronary circulation, significantly increased at 24 h after PCI in patients with AMI (group MI, n=17) in contrast with angina pectoris (n=10). Soluble CD40L levels in CS showed earlier peak, yielding trans-cardiac gradient, at 9 h in both groups. The maximum (max) release of IL-6 in MI, but not sCD40L, positively correlated with end-diastolic volume index (R=0.84) and negatively with ejection fraction (R=-0.66) by contrast ventriculography at 6-month follow up. Immunohistological study revealed the expression of CD40L in intra-coronary occlusive and mural thrombi. Aspirating thrombectomy significantly reduced the increase in both sCD40L levels and MMP-9 activity, but not max IL-6 release in MI.

CONCLUSIONS

In contrast with myocardial injury represented by IL-6 release, acute rise in sCD40L levels with the MMP-9 activation in the coronary circulation may possibly reflect local inflammation with platelet activation and be a novel marker of plaque damage by PCI.

[Repeated percutaneous transluminal septal myocardial ablation leads to reduction of left ventricular outflow-tract pressure gradient in hypertrophic obstructive cardiomyopathy: a case report]

A 61-year-old man with hypertrophic obstructive cardiomyopathy was treated twice with percutaneous transluminal septal myocardial ablation (PTSMA). The first procedure improved the left ventricular outflow tract pressure gradient (LVOTG) from 148 to 48 mmHg and the New York Heart Association (NYHA) class from III to II in a week. However, the LVOTG increased to 197 mmHg and the NYHA class worsened to III within 3 months. In spite of medical treatment with beta-blocker, syncope attack occurred suddenly. Repeated PTSMA was performed. Just after the second procedure, the LVOTG did not decrease. However, the LVOTG decreased to 81 mmHg and the NYHA class improved to II with 3 months. The different response of pressure gradient in the acute and chronic phase with repeated PTSMA was interesting.

Procedural implications of intravascular ultrasound morphologic features of chronic total coronary occlusions

Although the success rates of percutaneous coronary intervention of chronic total occlusions (CTOs) have improved, morphologic features are not well known. We analyzed experience at 4 centers where intravascular ultrasound (IVUS) was performed in 67 native artery CTO lesions (mean CTO duration 6.3 months) just after the lesion was crossed with a guidewire (n = 7) or after dilatation with a 1.5-mm (n = 46) or 2.0-mm (n = 14) balloon. IVUS detected calcium somewhere in the CTO in 96%; however, only 68% had mild calcium. IVUS identified a proximal end of the CTO in all lesions, but a distal end of the CTO in only 50%. An intramural hematoma was observed in 34% of CTOs, suggesting that the guidewire frequently entered the medial space during successful recanalization. CTOs were longer, vessel area was smaller, and total calcium index was greater in lesions with hematomas (p = 0.003, 0.05, and 0.03, respectively). Inadequate reflow after the procedure was observed in 9% and was associated with longer lesions and intralesional calcium. CTO length as measured with angiography was shorter than the length as measured with IVUS (p = 0.02). Calcium was detected on the angiogram in 61% (p = 0.054 vs IVUS). Most typical angiographic findings associated with a low rate of procedural success were not associated with different IVUS morphologies. In conclusion, CTO lesions had multiple small calcium deposits, intramural hematomas were common and were indicative of guidewire penetration into the medial space during the CTO procedure, especially in long calcified lesions in smaller vessels, and inadequate reflow after the procedure was correlated with more complex CTO morphology.

Possible Role of Brain-Derived Neurotrophic Factor in the Pathogenesis of Coronary Artery Disease

Background— The neurotrophin (NT) family, including nerve growth factor NT-3 and brain-derived neurotrophic factor (BDNF), has a critical role in the survival, growth, maintenance, and death of central and peripheral neurons. NTs and their receptors are expressed in atherosclerotic lesions; however, their significance in cardiovascular disease remains unclear.

Methods and Results— To clarify the role of NTs in the pathogenesis of coronary artery disease, NT plasma levels in the aorta, coronary sinus, and peripheral veins of patients with unstable angina (n=38), stable effort angina (n=45), and non–coronary artery disease (n=24) were examined. In addition, regional expression of BDNF in coronary arteries was examined in autopsy cases and patients with angina pectoris by directional coronary atherectomy. The difference in BDNF levels, but not NT-3, between the coronary sinus and aorta was significantly greater in the unstable angina group compared with the stable effort angina and non–coronary artery disease groups. Immunohistochemical investigations demonstrated BDNF expression in the atheromatous intima and adventitia in atherosclerotic coronary arteries. BDNF expression was enhanced in macrophages and smooth muscle cells in atherosclerotic coronary arteries. Stimulation with recombinant BDNF significantly enhanced NAD(P)H oxidase activity and the generation of reactive oxygen species in cultured human coronary artery smooth muscle cells.

Conclusions— BDNF has an important role in atherogenesis and plaque instability via the activation of NAD(P)H oxidase.

[Impact of metabolic syndrome and diabetes mellitus on cardiovascular events in coronary artery disease without ischemia on stress thallium-201 single photon emission computed tomography after percutaneous coronary intervention]

OBJECTIVES

The metabolic syndrome defined by the National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III) is a predictor of cardiovascular events. However, the significance of metabolic syndrome for cardiovascular events has been not clarified in Japan. The impact of metabolic syndrome and diabetes mellitus on cardiovascular events was investigated, especially in the high risk group after percutaneous coronary intervention.

METHODS

We studied 456 patients (mean age 63 +/- 10 years, range 36-88 years) without ischemia on stress thallium-201 single photon emission computed tomography after percutaneous coronary intervention. The diagnosis of metabolic syndrome was made according to the modified NCEP ATP III criteria. Cardiovascular events were examined for mean 3.7 +/- 1.8 years (range 2.0-8.7 years). There were 196 patients without diabetes mellitus or metabolic syndrome (Group D - M -), 89 patients without diabetes mellitus but with metabolic syndrome (Group D - M +), 61 patients with diabetes mellitus but without metabolic syndrome (Group D + M -), and 110 patients with both diabetes mellitus and metabolic syndrome (Group D + M +).

RESULTS

The event-free survival curve in Group D - M + was significantly lower than that in Group D - M - (p < 0.05), but not different from that in Group D + M -. The survival curve was markedly lower in Group D + M + than that in Group D - M + (p < 0.005). The Cox proportional hazard model revealed that diabetes mellitus and metabolic syndrome were independent significant risk factors for events.

CONCLUSIONS

The diagnosis of metabolic syndrome was helpful for identification of patients with high cardiovascular event rate even in patients after percutaneous coronary intervention. The combination of metabolic syndrome and diabetes mellitus markedly increases the risk for cardiovascular events.

Interaction of oxidative stress and inflammatory response in coronary plaque instability: important role of C-reactive protein

OBJECTIVE

C-reactive protein (CRP), a predictor of cardiovascular events, localizes in atherosclerotic arteries and exerts proinflammatory effects on vascular cells. Reactive oxygen species (ROS) have been implicated in atherogenesis and plaque instability.

METHODS AND RESULTS

Expressional pattern of CRP in directional coronary atherectomy specimens from 39 patients was examined. Characteristics of histological plaque instability and higher levels of serum CRP and fibrinogen were associated with the CRP immunoreactivity. In situ hybridization revealed the presence of CRP mRNA in coronary vasculature. Furthermore, the expression of CRP mRNA and protein was detected in cultured human coronary artery smooth muscle cells (CASMCs) by reverse transcriptase-polymerase chain reaction and Western blotting. In addition, CRP was frequently colocalized with p22phox, an essential component of NADH/NADPH oxidase, which is an important source of ROS in vasculature. Moreover, the incubation of cultured CASMCs with CRP resulted in the enhanced p22phox protein expression and in the generation of intracellular ROS.

CONCLUSIONS

The expression of CRP in coronary arteries was associated with histological and clinical features of vulnerable plaque, and it had a prooxidative effect on cultured CASMCs, suggesting that it might play a crucial role in plaque instability and in the pathogenesis of acute coronary syndrome via its prooxidative effect.

Superoxide generation in directional coronary atherectomy specimens of patients with angina pectoris: important role of NAD(P)H oxidase

OBJECTIVE

NADH/NADPH oxidase is an important source of reactive oxygen species (ROS) in the vasculature. Recently, we demonstrated that p22(phox), an essential component of this oxidase, was expressed in human coronary arteries and that its expression was enhanced with the progression of atherosclerosis. The present study was undertaken to investigate its functional importance in the pathogenesis of coronary artery disease. For this aim, the expression of p22(phox), the distribution of oxidized low density lipoprotein (LDL), and the generation of ROS in directional coronary atherectomy (DCA) specimens were examined.

METHODS AND RESULTS

DCA specimens were obtained from patients with stable or unstable angina pectoris. The distribution of p22(phox) and of oxidized LDL was examined by immunohistochemistry. The generation of superoxide in DCA specimens was assessed by the dihydroethidium method and lucigenin-enhanced chemiluminescence. ROS were closely associated with the distribution of p22(phox) and oxidized LDL. Not only inflammatory cells but also smooth muscle cells and fibroblasts generated ROS. There was a correlation between ROS and the expression of p22(phox) or oxidized LDL. The generation of ROS was significantly higher in unstable angina pectoris compared with stable angina pectoris.

CONCLUSIONS

ROS generated by p22(phox)-based NADH/NADPH oxidase likely mediate the oxidative modification of LDL and might play a major role in pathogenesis of atherosclerotic coronary artery disease.

Structure determination and total synthesis of a novel antibacterial substance, AB0022A, produced by a cellular slime mold

A novel antibacterial substance, AB0022A, was isolated from the cellular slime mold Dictyostelium purpureum K1001. It inhibited the growth of Gram-positive bacteria, and its MICs ranged from 0.39 to 50 microg/ml. Because AB0022A was a highly substituted aromatic compound, we could not determine its structure based on only its physico-chemical and spectral data. We therefore used a dehalogenated derivative from AB0022A and deduced that its structure was 1,9-dihydroxy-3,7-dimethoxy-2-hexanoyl-4,6,8-trichlorodibenzofuran . To confirm this structure, we synthesized the compound having the deduced structure. The synthetic compound was identical to naturally occurring AB0022A.

Morphology of vulnerable coronary plaque: insights from follow-up of patients examined by intravascular ultrasound before an acute coronary syndrome

OBJECTIVES

To determine the morphologic features of coronary plaques associated with acute coronary syndrome, we prospectively followed patients with atherosclerotic disease identified by intravascular ultrasound (IVUS).

BACKGROUND

Although clinical evaluation of the vulnerable atherosclerotic plaque is important, few data exist regarding the morphology of the vulnerable plaque in clinical settings.

METHODS

We examined 114 coronary sites without significant stenosis by angiography (<50% diameter stenosis) in 106 patients. All the sites exhibited atherosclerotic lesions by IVUS. These lesions consisted of 22 concentric and 92 eccentric plaques with a percent plaque area averaging 59 +/- 12%.

RESULTS

During the follow-up period of 21.8 +/- 6.4 months (range 1 to 24), 12 patients had an acute coronary event at a previously examined coronary site at an average of 4.0 +/- 3.4 months after the initial IVUS study. All the preexisting plaques related to the acute events exhibited an eccentric pattern and the mean percent plaque area was 67 +/- 9%, which was greater than plaque area in the other 90 patients without acute events (57 +/- 12%, p < 0.05). There was no statistically significant difference in lumen area between two patient groups (6.7 +/- 3.0 vs. 7.5 +/- 3.7 mm2). Among 12 coronary sites with an acute occlusion, 10 sites contained the echolucent zones, eight of these shallow and two deep, likely representing a lipid-rich core. In 90 sites without acute events, an echolucent zone in the shallow portion was seen at only four sites (p < 0.05).

CONCLUSIONS

Large eccentric plaque containing an echolucent zone by IVUS can be at increased risk for instability even though the lumen area is preserved at the time of initial study. Compensatory enlargement of vessel wall due to remodeling may contribute to the relatively small degree of stenosis by angiography.

(3-substituted benzyl)thiazolidine-2,4-diones as structurally new antihyperglycemic agents

A series of 3-[(2,4-dioxothiazolidin-5-yl)methyl]benzamide derivatives was prepared as part of a search for antidiabetic agents. A structure-activity relationship study of these compounds led to the identification of 5-[(2,4-dioxothiazolidin-5-yl)methyl]-2-methoxy-N-[[4-(trifluorome thyl)-phenyl]methyl]benzamide (KRP-297) as a candidate drug for the treatment of diabetes mellitus.

[Severe pulmonary hypertension due to mitral regurgitation without overt sign of congestive heart failure: a case report]

A 49-year-old man was found to have a heart murmur at a local hospital and was referred to our hospital for further examination. Although he had no signs of congestive heart failure, echocardiography and cardiac catheterization showed severe pulmonary hypertension caused by severe mitral regurgitation. Mitral valve replacement was performed, followed by reduction of pulmonary artery pressure. This patient had an unusual combination of no signs of lung congestion despite severe mitral regurgitation with pulmonary hypertension.

Three-dimensional reconstruction of intravascular ultrasound images of coronary stents using an ECG-gated pull-back device

Three-dimensional reconstruction (3D-R) of intravascular ultrasound (IVUS) images is not yet satisfactory because of artifacts caused by cardiac movement. This problem can be overcome with a new device, an electrocardiographic (ECG)-gated pull-back system. Using this device a catheter is pulled back stepwise gated by the ECG, and IVUS dynamic images of an entire cardiac cycle are acquired at each step. We performed 3D-R of IVUS images of stents using this new device in six patients with Palmaz-Schatz coronary stent implantation. We obtained precise 3D images in all cases, and stent structure was visualized in detail. In conclusion, use of an ECG-gated pull-back device enables precise 3D-R of IVUS images and provides useful information on the coronary artery.

[Left ventricular pseudoaneurysm recognized 9 years after mitral valve replacement and repeated heart failure of 3 years duration: a case report]

A 66-year-old woman had suffered from repeated heart failure beginning 6 years after mitral valve replacement. Left ventricular pseudoaneurysm was discovered 9 years after the replacement, while no evidence including histology was obtained for the cause of the pseudoaneurysm except the mitral valve replacement. The progression of aortic valve stenosis and the formation of the pseudoaneurysm may have contributed to the onset of congestive heart failure. Surgical treatment was successful. Although left ventricular pseudoaneurysm after mitral valve replacement is rare, careful echocardiographic examination is necessary for detecting such a complication in patients after surgery.

Exercise beta-methyl iodophenyl acid (BMIPP) and resting thalium delayed single photon emission computed tomography (SPECT) in the assessment of ischemia and viability

To clarify the significance of exercise BMIPP (beta-methyl iodophenyl pentadecanoic acid) and resting T1 delayed single photon emission computed tomography (SPECT) in the assessment of ischemia and viability, we studied maximal exercise-loading BMIPP SPECT following rest-injected T1 3 h SPECT in 11 control subjects, 20 patients with effort angina and 38 patients with old myocardial infarction. The left ventricular wall on ECT was divided into 9 segments. BMIPP and T1 uptake were scored as 0 = normal, 1 = reduced, 2 = severely reduced, or 3 = absent. Discordance was defined as when segments with a reduced BMIPP uptake had a better resting T1 uptake. Significant coronary artery stenosis was defined as stenosis of 75% or greater on coronary arteriogram. Left ventricular wall motion was assessed as either normokinesis, hypokinesis, severe hypokinesis, akinesis or dyskinesis on left ventriculogram. When discordance was considered to be a marker of ischemia, the sensitivity and specificity in effort angina and control subjects were 95.2% and 84.6% for patients and 83.9% and 94.4% for diseased vessels, respectively. There were no differences between the sensitivity and specificity in left anterior descending artery (LAD), left circumflex artery (LCx) and right coronary artery (RCA) lesions (83.3%, 95.5% in LAD, 83.3%, 95.5% in LCx, 85.7%, 92.6% in RCA, respectively). All of the patients with old myocardial infarction had reduced exercise BMIPP uptake in infarcted regions. In old myocardial infarction, 35 patients had segments with discordant uptake. Discordance was observed in 75 (91.5%) of 82 segments with hypokinesis, and in 24 (92.3%) of 26 segments with severe hypokinesis. Even among the 36 segments with akinesis or dyskinesis, 25 (69.0%) had discordant uptake. When discordance in the infarcted region was considered to be a marker of viability, regions with severe asynergy showed a high possibility of viability. Thus, discordant uptake on exercise BMIPP and resting T1 delayed SPECT may be a useful marker of ischemia in effort angina and of viability in old myocardial infarction.

Genotoxic effect of griseofulvin in somatic cells of Drosophila melanogaster

Griseofulvin (GF), a carcinogenic spindle poison, was tested in two types of somatic-cell assays of Drosophila melanogaster, one of which detects the induction of DNA damage and the other mutation/mitotic recombination. In both assays, GF was fed to tester larvae and genetic endpoints examined after emergence. In the wing spot test, trans-heterozygous flies carrying mwh and flr3 wing-hair mutations produced both significant and dose-dependent increases in the frequency of mwh single spots over the control level but no increase of twin spots. In the DNA repair test, double-mutant larvae carrying both mei-9(a) (excision repair-defective) and mei-41(D5) (postreplication repair-defective) mutations showed hypersensitivity to killing by GF compared with their DNA repair-proficient counterparts, suggesting that GF caused potentially lethal DNA damages which were efficiently repaired by the DNA repair-proficient but not -defective larvae. These lines of evidence clearly demonstrate that GF is genotoxic in somatic cells of Drosophila. It is noted that (1) GF-fed larvae showed a developmental delay and (2) surviving adult flies had morphological abnormalities in their eyes and wings.

Studies of neuroregulators in the brain stem of SIDS

Some dysmaturity of neuroregulator neuronal systems may be responsible for brain stem disorders. These disorders may partly explain the mechanism of death in SIDS. The available data using microbiochemical assays, immunocytochemical techniques and autoradiographic methods seem to show anomalies of some monoaminergic and of some peptidergic systems, especially in the medulla oblongata. All these data need to be confirmed by further studies. It should be understood that one positive effect of such neuroanatomical study on SIDS is to gain 'normative' data on the human brain during development.

Computer-aided interpretation of coronary cineangiograms. Accuracy of automatic detection of stenotic lesions

To accurately diagnose stenotic lesions on coronary cineangiograms, an automatic detection method using computer image processing was developed. We evaluated its accuracy by comparing the results of computer-aided interpretation (CAI) with those obtained independently by 3 observers. Evaluation was performed on 129 segments from 27 arteries visualized on angiograms obtained in 18 patients. The detection rates of stenosis of the 3 observers by pure visual interpretation were 7.0%, 27.9%, and 17.1%, and using CAI 40.0%, 42.6%, and 47.3%. By computer recognition alone, a detection rate of 51.9% was achieved. The agreement by at least 2 observers (consensus) on the sites with lesions was 41.1% while the consensus of computer recognition regarding the sites with lesion was 40.3%. Therefore, our findings indicated that computer recognition of cineangiograms is likely to result in overdetection of lesions. However, all 3 observers detected stenotic lesions better with CAI than with pure visual interpretation. Accordingly, CAI may improve the reliability of cineangiographic diagnosis.

[Contractile properties of coronary artery bypass conduit--comparison between saphenous vein and internal mammary artery]

This study was designed to examine the response of coronary artery bypass conduit to serotonin, phenylephrine, and ergonovine as provocation agents of vasoconstriction. Saphenous veins (SV) and internal mammary arteries (IMA) were obtained during coronary artery bypass grafting (CABG), and their contractile properties were measured using isometric contraction recording apparatus. Both SV and IMA showed sigmoid contraction curves indicating dose dependence to ergonovine, serotonin, and phenylephrine. The concentration-response relations for phenylephrine showed a similar curve in both SV and IMA, however, those for ergonovine and serotonin showed a leftward shift in SV compared with IMA. Half maximum effective dose for ergonovine and serotonin were less in SV than IMA. From these results, it was suggested that "perioperative spasm" during CABG might occur not only in coronary arteries but also in the graft conduit itself. Graft spasm might be a possible mechanism for occlusion of the bypass graft. In conclusion, greater hyperreactivity of SV compared with IMA in response to ergonovine and serotonin was suggested, so it is concluded that, from this point of view, IMA is more suitable for use in CABG.

Role of serotonin, histamine, and thromboxane A2 in platelet-induced contractions of coronary arteries and aortae from rabbits

The present study was undertaken to clarify the underlying mechanisms responsible for contractions of isolated coronary arteries and aortae from rabbits in response to thrombin-stimulated autologous platelets. Thrombin-stimulated platelets evoked potent contractions of both arteries in a platelet concentration-related manner. Pretreatment of platelets with aspirin, which almost completely inhibited thromboxane A2 synthesis but not the release reaction of biologic monoamines from platelets, caused only slight suppression of platelet-induced contractions of both arteries. Ketanserin as well as methysergide markedly inhibited aortic contractions to platelets. In contrast, the contractile responses of coronary arteries to platelets were suppressed by methysergide but not by ketanserin. Pretreatment of the arteries with diphenhydramine did not inhibit the aortic responses to platelets, but significantly suppressed coronary arterial contractions induced by higher concentrations of platelets. Phentolamine had no inhibitory effects on the responses of either artery to platelets. Pretreatment of arteries with aspirin did not affect the contractile responses of either artery to platelets. The contractile responses of aortae to exogenously administered serotonin were competitively antagonized by ketanserin, but those of coronary arteries were not. Coronary contractions to serotonin were competitively inhibited by methiothepin and significantly suppressed by methysergide. The contractile responses of both arteries to histamine were antagonized by diphenhydramine but not by cimetidine. On the basis of our results obtained from studies in organ chamber, we conclude that a major role of thromboxane A2 was not demonstrated in platelet-induced contractions of the arteries, and that those of aortae were mainly mediated by platelet-derived serotonin at S2 receptor and those of coronary arteries at S1-like receptor. The contractions of coronary arteries in responses to higher concentrations of platelets were partly mediated by histamine at H1 receptor.

Analysis of the rat interpeduncular subnuclei by immunocytochemical double-staining for enkephalin and substance P, with some reference to the coexistence of both peptides

The rat interpeduncular nucleus (IPN) was immunocytochemically double-stained for enkephalin (ENK) and substance P (SP) on the same sections. On the basis of both peptidergic distribution patterns and topographic relationship, the IPN was divided into nine subnuclei and one cap: the rostral subnucleus (IP-R), the central subnucleus (IP-C), the rostral-lateral subnucleus (IP-RL), the main lateral subnucleus (IP-L), the caudal-lateral subnucleus (IP-CL), the dorsal-lateral subnucleus (IP-DL), the dorsal-medial subnucleus (IP-DM), the apical subnucleus (IP-A), the intermediate subnucleus (IP-I), and the dorsal cap (IP-Cap). As the descriptions of the IP-RL, IP-L, and IP-CL were inconsistent with previous reports, they were reevaluated; the IP-RL was proposed as the region situated in the lateral portion at rostral levels and characterized by the lack of ENK and SP immunoreactive structures, the IP-L as the region situated throughout the rostrocaudal extent in the lateral portion of the IPN and containing the highest density of SP immunoreactive fibers but no ENK immunoreactive fibers, and the IP-CL as the region situated just laterocaudal to the IP-L in the caudal pole of the IPN and containing ENK immunoreactive cells and fibers but no SP immunoreactive structures. Our results also showed that some cells in the IP-R have both ENK and SP immunoreactivity. This coexistence was observed in some small spherical cells of the IP-R, but rarely in larger oval-shaped cells, which occasionally showed only ENK immunoreactivity. In addition, paired ENK immunoreactive fiber bundles entering the IP-R were found to run just rostral to the paired SP immunoreactive columns, both of which composed parts of the interpedunculotegmental tract. A three-dimensional model representing the subnuclear organization of the IPN was proposed on the basis of the present results.