Morimichi Setsuda

Impact of coronary artery remodeling on clinical presentation of coronary artery disease: an intravascular ultrasound study.

OBJECTIVES We examined the association between the features of the culprit lesion in coronary artery disease (CAD) and clinical presentation as shown by intravascular ultrasound (IVUS). BACKGROUND The association between coronary remodeling pattern and clinical presentation of CAD is unclear. METHODS We analyzed 125 selected patients who underwent preintervention IVUS. Acute myocardial infarction (AMI) and unstable angina pectoris (UAP) were categorized as an acute coronary syndrome (ACS), and stable angina pectoris (SAP) and old myocardial infarction (OMI) as stable CAD. Coronary remodeling patterns and plaque morphology of the culprit lesion obtained by IVUS were analyzed in terms of their association with clinical presentation or angiographic morphology. RESULTS Angiographically complex lesions were associated with ACS and OMI. In patients with a complex lesion, positive remodeling was observed more frequently than in those with a simple lesion. In AMI and UAP, positive remodeling was observed more frequently than in SAP and OMI (82% vs. 78% vs. 33% vs. 40%, respectively, p < 0.0001). The remodeling ratio was greater in AMI and UAP than in SAP and OMI (1.26 +/- 0.15 vs. 1.11 +/- 0.10 vs. 0.94 +/- 0.11 vs. 0.96 +/- 0.13, respectively, p < 0.0001). Furthermore, within ACS, the remodeling ratio was greater in AMI than in UAP (1.26 +/- 0.15 vs. 1.11 +/- 0.10, respectively, p < 0.05), whereas the frequency of positive remodeling was not different. CONCLUSIONS Positive remodeling was more frequently observed in ACS than in stable CAD. Moreover, the degree of positive remodeling was greater in AMI than in UAP. These results may reflect the impact of remodeling types and its degree in the culprit lesion of CAD on clinical presentation.

Effects of trapidil (triazolopyrimidine), a platelet-derived growth factor antagonist, in preventing restenosis after percutaneous transluminal coronary angioplasty

Trapidil (triazolopyrimidine), a platelet-derived growth factor antagonist, is a potential inhibitor of intimal proliferation after percutaneous transluminal coronary angioplasty (PTCA). To study its efficacy, 72 patients were randomized to receive Trapidil (600 mg/day orally for 1 week before PTCA and for 4 to 6 months after PTCA; n = 36) or aspirin and dipyridamole (aspirin, 300 mg/day, and dipyridamole, 150 mg/day; n = 36). At entry, both groups were comparable with regard to age, sex, dilated vessels, severity of pre-PTCA stenosis, residual stenosis after PTCA, and prevalence of coronary risk factors. Repeat coronary angiography was performed 6 months after PTCA. Restenosis, defined as the loss of at least 50% of the gain in luminal diameter accomplished by dilation, was present in seven patients (19.4%) in the trapidil group and 15 patients (41.7%) in the aspirin-dipyridamole group (p less than 0.05). The progression of stenosis in patients with less than 30% residual stenosis was significant in both groups. Furthermore, in the patients with residual stenosis of more than 30%, progression of stenosis was less in the trapidil group than in the aspirin-dipyridamole group. Thus trapidil was useful in preventing intimal proliferation after PTCA, especially in patients with more than 30% residual stenosis after PTCA.

Impact of heart rate on mechanical dyssynchrony and left ventricular contractility in patients with heart failure and normal QRS duration

The quantification of mechanical dyssynchrony has important diagnostic value and may help to determine optimal therapy in heart failure (HF). We hypothesized that mechanical dyssynchrony may be augmented at increased heart rates in patients with HF and normal QRS duration.

Advanced atrioventricular block induced by obstructive sleep apnea before oxygen desaturation

We report a patient with transient advanced atrioventricular (AV) block induced by obstructive sleep apnea (OSA). This 54-year-old man was diagnosed as having severe OSA and AV block with ventricular asystole for more than 6 s during overnight polysomnography, which occurred just from the onset of OSA before oxygen desaturation had occurred. An electrophysiological study revealed normal AV conduction system function and normal His-Purkinje system function. The resolution of OSA with continuous positive airway pressure therapy improved the advanced AV block. Therefore, the bradyarrhythmia was determined to be an OSA-induced AV block that occurred before oxygen desaturation.

Late development of an aneurysm of a saphenous vein used as an aortocoronary conduit

A case of a large saphenous vein aortocoronary aneurysm that developed late after coronary artery bypass grafting is presented. This is the first case of a large saphenous vein aortocoronary aneurysm identified by serial angiography and 3-dimensional computed tomographic scanning.

A case of ventricular fibrillation not detected by an automated external defibrillator

We report a case of ventricular fibrillation (VF) which an automated external defibrillator (AED) could not detect. A 13‐year‐old girl collapsed just after playing basketball. Cardio pulmonary resuscitation (CPR) was started immediately and 5 minutes later an AED was applied by a rescue team. The monitor of the AED displayed typical VF, but the AED did not detect it as VF. The VF was not detected during 2 more attempts. Detection occurred on the fourth attempt, and counter‐shock was successfully delivered, but the process took an extra 9 minutes. After the event, the girl was diagnosed with a latent type of prolonged QT syndrome. We analyzed the reason why the VF was not detected by the AED and found that the ECG detected by the AED fell outside the devices parameters for ventricular tachycardia (VT) or VF. We emphasize that the AED is an excellent device, but we should also be aware of its limitations.