Cardiac iodine-123-metaiodobenzylguanidine scintigraphy may be useful to identify pathologic from physiologic sinus bradycardia.

BACKGROUND: Sinus bradycardia includes pathologic sick sinus syndrome (SSS) and physiologic bradycardia such as athletes' heart. Pacemaker implantation is indicated for patients with symptomatic SSS; however, the indication remains difficult to determine in those with mild and/or unspecific symptoms. The sympathetic tone is increased in response to reduced cardiac output in SSS, whereas excessive vagal tone has been seen in physiological bradycardia. We sought to determine if cardiac iodine-123-metaiodobenzylguanidine scintigraphy (123 I-MIBG) was useful in differentiating pathologic from physiologic sinus bradycardia. METHODS: Twenty consecutive patients presenting with continuous sinus bradycardia (heart rate of <50 beats/min) in our outpatient clinic (male, eight patients; age, 70 ± 12 years old) were enrolled. The indication for a pacemaker implantation was determined by an experienced electrophysiologist in compliance with the international guidelines. The sympathetic nervous tone was assessed by cardiac 123 I-MIBG. RESULTS: Eight patients (40%) were clinically diagnosed as SSS (type I) including four suffering from obvious symptoms (syncope or dizziness) and four suffering from mild symptoms (fatigue), and had an indication for a pacemaker implantation. The patients with SSS indicated for a pacemaker implantation had a lower early heart-to-mediastinum ratio (2.0 ± 0.6 vs 2.5 ± 0.2, P = 0.043), lower delayed heart to mediastinum ratio (2.0 ± 0.8 vs 2.8 ± 0.3, P = 0.026), and higher washout rate (34 ± 6.0 vs 26 ± 6.0, P = 0.008) than those without. CONCLUSION: Excessive sympathetic tone detected by 123 I-MIBG may serve as an adjunct to determine the indication for a pacemaker implantation in sinus bradycardia.

Serial angioscopic evidence of incomplete neointimal coverage after sirolimus-eluting stent implantation: comparison with bare-metal stents.

BACKGROUND: The time course of neointimal formation after stent implantation has not been studied extensively by angioscopy in the drug-eluting stent era. METHODS AND RESULTS: Serial angioscopic findings at first follow-up (3.6+/-1.1 months), second follow-up (10.5+/-1.6 months), and third follow-up (21.2+/-2.2 months) after stent implantation were compared between sirolimus-eluting stents (SES, n=17) and bare-metal stents (BMS, n=11). Neointimal coverage, thrombus, and presence of yellow plaques underneath the stents were assessed. Neointimal coverage was graded as follows: grade 0, stent struts were fully visible; grade 1, struts bulged into the lumen, although they were covered; grade 2, struts were embedded by the neointima but were seen translucently; or grade 3, struts were fully embedded and invisible. Neointimal coverage was remarkably different between SES and BMS at each follow-up point. Neointimal coverage grade was 1.1+/-0.5 in SES versus 2.9+/-0.3 in BMS at the first follow-up (P<0.0001), 1.1+/-0.5 in SES versus 3.0+/-0.0 in BMS (P<0.0001) at the second follow-up, and 1.3+/-0.5 in SES versus 3.0+/-0.0 in BMS at the third follow-up (P=0.0009). No significant serial changes in coverage grade were noted in the BMS group, whereas coverage grade slightly but significantly increased at the third follow-up in the SES group (P<0.05). Thrombi were detected in 4 SES: a red thrombus was seen from the first to the third follow-up in 2; another was detected only at the third follow-up; and the fourth was seen at the first follow-up but disappeared at the second follow-up, associated with a new white thrombus despite dual antiplatelet therapy. Yellow plaques had disappeared by the time of the second follow-up in BMS. In contrast, yellow plaques were exposed in 71% of SES at the first follow-up and remained exposed until the third follow-up. Neointimal coverage grades correlated with thrombi (P=0.002) and with yellow plaques (P<0.0001). CONCLUSIONS: Serial angioscopic findings up to 2 years after SES implantation were markedly different from those after BMS. Neointimal coverage was completed by 3 to 6 months in BMS. In contrast, SES demonstrated the presence of thrombi and yellow plaques even as much as 2 years after implantation.

Effect of exercise on frequency of stent fracture in the superficial femoral artery.

Stent fracture has emerged as a new problem in the percutaneous transluminal angioplasty of the superficial femoral artery (SFA). The aim of our study was to delineate the factors influencing nitinol stent fracture in the SFA. Forty consecutive patients with peripheral artery disease who underwent rescue stenting with a nitinol stent (Luminexx, Bard) in the SFA were enrolled between May 2004 and January 2005. Follow-up angiography was performed 13.6+/-1.0 months later to detect stent fracture. Stent fracture occurred in 11 patients (28%). Lesion length>100 mm, the number of stents used, the lesion involving the distal SFA, chronic total occlusion, and walking>5,000 steps per day were more frequently observed in those with stent fracture than in those without fracture. Of these variables, walking>5,000 steps per day was the strongest independent determinant associated with stent fracture by discriminant analysis (p=0.0027). Vigorous exercise adversely affects stent fracture in patients implanted with a nitinol stent in the SFA.

Plaque gruel of atheromatous coronary lesion may contribute to the no-reflow phenomenon in patients with acute coronary syndrome.

BACKGROUND: No-reflow associated with direct angioplasty (PCI) of patients with acute coronary syndromes (ACS) is associated with unfavorable results. METHODS AND RESULTS: We used a new thrombectomy device to treat 51 lesions in 48 consecutive ACS patients (40 male and 8 female; mean age 63 years) and conducted a microscopic analysis of aspirates and blood samples retrieved from the culprit coronary artery. The first aspirate was collected before PCI and the second was collected separately after percutaneous transluminal coronary angioplasty or stenting, including samples from the no-reflow lumen. Light microscopy showed that the materials obtained from the pre-PCI aspiration consisted of thrombus in 37.5%, thrombus and atheroma in 35.0%, and atheromatous plaque in 27.5%. The materials collected from the post-PCI aspiration were thrombus in 8.3%, thrombus and atheroma in 41.7%, and atheromatous plaque in 50.0%. We then compared the 9 lesions (19.1%) with no-reflow to those without no-reflow. There was no difference in the pre-PCI aspirates. However, after PCI, there was more atheromatous plaque retrieved from patients with no-reflow (P<0.001) as well as significantly more platelet and fibrin complex, macrophages, and cholesterol crystals in the blood aspirated from no-reflow cases. Aspiration of these elements improved the no-reflow in 7 of 9 lesions to TIMI-3 flow. CONCLUSIONS: No-reflow after angioplasty may be caused by gruel that formed from an atheroma attributable to mechanical plaque disruption during intervention.

Detection of diastolic abnormality by dyssynchrony imaging: correlation with coronary artery disease in patients presenting with visibly normal wall motion.

BACKGROUND: Post-systolic shortening (PSS) is a sensitive indicator of myocardial ischemia. METHODS AND RESULTS: We have developed a tissue Doppler imaging technique that portrays PSS, and whether PSS correlates with coronary artery disease (CAD) was investigated in 186 patients presenting with chest pain and normal echocardiograms. Delays of the displacement peaks from end-systole were calculated in the apical views and displayed from green (0 ms) to red (>or=100 ms): detection of diastolic abnormality by dyssynchrony imaging (DADI). CAD was judged positive by DADI when the left ventricular segments were color-coded red. Patients subsequently underwent thallium-201 myocardial perfusion single-photon emission computed tomography (n=150), coronary angiography (CAG, n=74), or both (n=37). CAD(-) was defined as negative scintigraphy test and/or no significant coronary artery stenosis by CAG. In 43 patients (23%), CAD(+) was confirmed by CAG as >75% diameter stenosis. DADI predicted CAD with sensitivity of 60%, specificity of 75%, predictive accuracy of 72%, positive predictive value of 42%, and negative predictive value of 86%. Among 74 patients who underwent CAG, sensitivity was best for the left anterior descending artery. CONCLUSIONS: DADI detected the regional diastolic abnormality, which correlated with the presence of CAD in patients presenting with visibly normal wall motion.

Heterogeneous arterial healing in patients following paclitaxel-eluting stent implantation: comparison with sirolimus-eluting stents.

OBJECTIVES: We angioscopically compared paclitaxel-eluting stents (PES) and sirolimus-eluting stents (SES) to explore differences in arterial healing. BACKGROUND: Drug-eluting stents may demonstrate different arterial healing processes. METHODS: Angioscopy was performed 9 +/- 2 months after 30 PES and 36 SES were implanted initially in the native coronary artery. Heterogeneity of the neointimal coverage (NIC) as well as the dominant grade was examined. Neointimal coverage was defined as follows: grade 0 = fully visible struts; grade 1 = struts bulged into the lumen, but covered; grade 2 = embedded, but translucent struts; grade 3 = invisible struts. Heterogeneity was judged when the NIC grade variation >or=1. Thrombi and yellow plaques (YP) were also explored. RESULTS: In-stent late loss (0.44 +/- 0.44 mm vs. 0.13 +/- 0.33 mm; p < 0.0001) and dominant NIC grade (1.8 +/- 1.1 vs. 1.3 +/- 0.7; p = 0.02) were greater in PES than in SES. Of PES, 48% showed the heterogeneity of 1 grade; 26% showed that of 2 grades. Of SES, 53% showed homogeneous coverage; the remaining SES showed the heterogeneity of 1 grade; and 72% showed dominant grade 1. Thrombi were more common in PES than in SES (43% vs. 19%; p = 0.04). Both stents commonly revealed YP (83% vs. 78%; p = 0.76). CONCLUSIONS: NIC was more heterogeneous in PES, associated with a higher incidence of thrombi. Homogeneous NIC may be an important factor for competent arterial healing.

Cilostazol reduces restenosis after endovascular therapy in patients with femoropopliteal lesions.

BACKGROUND: Despite the recent development of endovascular therapy (EVT), a high incidence of restenosis remains as an unsolved issue in patients presenting with femoropopliteal lesions. We investigated whether cilostazol reduces restenosis after successful EVT for de novo femoropopliteal lesions. METHODS: This study was designed as a prospective, randomized, open-label, blinded end point study in a single institution. Between March 2004 and June 2005, we randomized 127 patients who were successfully treated with EVT for de novo femoropopliteal lesions to receive cilostazol (200 mg/d, n = 63) or ticlopidine (200 mg/d, n = 64) in addition to aspirin (100 mg/d). Antiplatelet medications were started at least 1 week before EVT and were continued until the end of follow-up. Patency was defined by duplex ultrasound imaging with peak systolic velocity ratio >2.4. RESULTS: There were no significant differences in the patients and lesion characteristics. Sixteen patients dropped out of the study protocol, six of whom were withdrawn due to adverse drug effects (cilostazol, n = 5; ticlopidine, n = 1; P = .09). Ten patients died (cilostazol, n = 4; ticlopidine, n = 6; P = .53) during the follow-up period. Patency rates at 12, 24, and 36 months were 87%, 82%, and 73% in the cilostazol group and 65%, 60%, and 51% in ticlopidine group by intention-to-treat analysis (P = .013) and were 87%, 82%, and 73% in the cilostazol group and 64%, 57%, and 48% in the ticlopidine group (P = .0088) by as-treated analysis. Freedom from target lesion revascularization and all adverse events (restenosis, amputation, and death) was significantly higher in cilostazol group than in ticlopidine group (P = .036, P = .031). No acute, subacute, or chronic thrombotic occlusion was encountered, and bleeding complication rates were similar between the two groups. CONCLUSIONS: Cilostazol significantly reduces restenosis after EVT in femoropopliteal lesions.

Endovascular therapy for limb salvage in a case of critical lower limb ischemia resulting from fibromuscular dysplasia.

Fibromuscular dysplasia (FMD) is a nonatherosclerotic, noninflammatory vascular disease that mostly affects the renal and internal carotid arteries, rarely complicating lower limbs. We report a case of FMD complicating critical limb ischemia due to the obstruction of below the knee arteries, diagnosed and treated with the support of skin perfusion pressure (SPP) measurement. Initial angiogram revealed the anterior tibial artery (ATA) was subtotally occluded showing a "strings of beads" pattern, which is typical of the arteries affected by FMD. SPP guided endovascular therapy was successful for ATA lesions. Intractable rest pain subsequently disappeared and the ulcer was completely healed without amputation.

Positive isovolumic relaxation velocity detected by a spectral tissue Doppler mapping technique as an indicator of coronary artery disease: a prospective study.

BACKGROUND: A positive myocardial velocity during isovolumic relaxation phase (V(IR)) detected by spectral tissue Doppler imaging has been shown to indicate ischemic myocardium. We sought to examine the diagnostic value of positive V(IR) for detecting coronary artery disease (CAD) in patients with chest pain and apparently normal left ventricular contraction. METHODS: A total of 138 patients (74 men, age 69 +/- 8 years) underwent spectral Doppler tissue imaging measurements at the annular and mid left ventricular levels in the apical 4- and 2-chamber views (8 points/patient) at rest in addition to standard echocardiography. Subsequently, patients underwent thallium-201 myocardial perfusion single photon emission computed tomography (n = 98) and/or coronary angiography (n = 60). The duration of positive V(IR) was also assessed. CAD was diagnosed by having more than 75% diameter stenosis in coronary angiography. RESULTS: CAD was present in 41 patients (30%). The duration of positive V(IR) was distributed from 0 to 280 milliseconds with the median value of 100 milliseconds. Presence of positive V(IR) predicted CAD with sensitivity of 80% and specificity of 61%. CONCLUSIONS: Positive V(IR) detected by spectral tissue Doppler imaging is a useful indicator of CAD in patients with apparently normal left ventricular contraction and chest pain.

[Shoshin beriberi complicating severe pulmonary hypertension: a case report].

A 44-year-old male was admitted to our hospital for dyspnea, associated with severe pulmonary hypertension. The patient fell into a shock state on the next day. Hemodynamic measurements revealed high output heart failure with low peripheral vascular resistance. We suspected shoshin beriberi, a fulminant form of cardiac beriberi, by ruling out other common causes of pulmonary hypertension. The rapid recovery after intravenous thiamine administration and the patient's history of improper diet strongly supported the diagnosis. The present case of shoshin beriberi complicating severe pulmonary hypertension shows that history taking is important in elucidating the etiology and selecting the correct treatment.

Sustained attenuation of neointimal coverage over the stent following brachytherapy for in-stent restenosis: angioscopic findings.

BACKGROUND: The nature of the vessel lumen following vascular brachytherapy (VBT) has not been extensively explored in the clinical setting. METHODS AND RESULTS: By using angioscopy, 33 stents treated with percutaneous balloon angioplasty with or without VBT for in-stent restenosis after 8.9 +/- 2.1 months of the treatment were followed (VBT =14 lesions; control =19 lesions). Neointimal coverage, stent attachment, and the presence of red or white thrombi were factors that were assessed. The majority of the stents (74%) were fully covered with non-transparent neointima in the control group. In contrast, stent struts were clearly seen in 57% lesions with VBT. The absence of neointima with glittering stent struts were only seen in 29% of lesions in VBT (p = 0.03). Incomplete stent attachment was not detected in the controls, whereas 14% were in VBT (p = 0.17). Red thrombi were observed in 14% with VBT and in 16% in controls, which showed that there was a similar incidence regardless of the treatment. Neither exposure of stent struts (p = 0.5) nor incomplete stent attachment (p = 1.0) was related to thrombi. CONCLUSIONS: The exposure of stent struts and incomplete stent attachment were occasionally observed by angioscopy even 9 months after VBT for the treatment of in-stent restenosis.

Elevation of plasma matrix metalloproteinase-9 in the culprit coronary artery in patients with acute myocardial infarction: clinical evidence from distal protection.

BACKGROUND: Although the elevation of circulating plasma matrix metalloproteinase (MMP)-9 levels in patients with acute myocardial infarction (AMI) has been documented, the origin of MMP-9 remains unclear. METHODS AND RESULTS: Plasma MMP-9 levels in both the peripheral circulation and coronary arteries were measured in patients with AMI (n=23) and with stable angina pectoris (SAP, n=10) during percutaneous coronary intervention (PCI) with a distal protection device. Blood samples were collected from the femoral artery (FA) and the coronary artery before (Initial) and after (Second) dilation of the culprit lesion. Coronary sinus blood samples were obtained immediately after PCI (n=7). Coronary artery plaque fragments were aspirated in patients with AMI (n=20) and compared with those from patients with SAP who underwent directional atherectomy (n=10). MMP-9 levels in Initial and Second were significantly higher in patients with AMI than in patients with SAP (p<0.01). In AMI patients MMP-9 levels were significantly higher in Initial than in the FA (p<0.05), and were further increased in Second (p<0.0001), whereas those in the coronary sinus were similar to the FA. Immunohistochemistry revealed augmented MMP-9 expression in the coronary artery plaque fragments from AMI patients. CONCLUSIONS: MMP-9 is mainly released into the coronary circulation from the coronary artery plaque in patients with AMI.

Cilostazol reduces target lesion revascularization after percutaneous transluminal angioplasty in the femoropopliteal artery.

BACKGROUND: Although percutaneous transluminal angioplasty (PTA) is being widely used for the treatment of stenosis of peripheral arteries, the high in-stent restenosis rate (50-60%) in the femoropopliteal artery still remains an unsolved issue. Cilostazol is a unique antiplatelet drug that has vasodilatory effects and inhibits smooth muscle cell proliferation. METHODS AND RESULTS: A total of 141 consecutive patients scheduled for PTA in the femoropopliteal artery between September 1999 and April 2004 were retrospectively analyzed for the use of cilostazol. Target lesion revascularization (TLR) was defined as repeated PTA in patients who had a recurrence of symptoms with diameter stenosis >50% by angiography. Patient and lesion characteristics were similar between the cilostazol (+) and cilostazol (-) groups. Use of other medications was similar between the groups, except for ticlopidine, which was more frequently used in the cilostazol (-) than in the cilostazol (+) group (15% vs 61%, p<0.01). TLR was significantly reduced in the cilostazol (+) group (12% [8/68] vs 32% [23/73], p<0.01). CONCLUSIONS: Although this study was retrospective and nonrandomized, the results suggest that cilostazol reduces TLR after PTA in the femoropopliteal artery.

Disappearance of intima over the stent and ulcer formation after intracoronary radiation for in-stent restenosis.

Little is known about the alterations of the vascular surface after radiation therapy for in-stent restenosis in humans, even though animal experiments suggest that delayed healing of the neointima is a cause of late thrombosis. Coronary angioscopy, together with coronary angiography, was performed at 3 months follow-up of 7 patients with in-stent restenosis who underwent beta-radiation therapy. Minimal lesion diameter (MLD) of the lesion increased from 1.00+/-0.30 mm (immediately before) to 2.44+/-0.39 mm (immediately after) and the MLD was well maintained 3 months later (2.34+/-0.62 mm) without any cases of restenosis. In 5 patients, the intima was so thin that some stent struts could be seen through it on angioscopy and in 2 of those, the intima over the stent had disappeared and 1 patient showed ulceration of the vascular wall beneath the stent. After intracoronary radiation therapy, the intima can become so thin that some stent struts are exposed to the lumen, which may be related to the occurrence of late thrombosis. Accordingly, patients who are treated with intracoronary radiation therapy may need long-term antiplatelet therapy.

No-reflow following dilatation of a coronary lesion with a large lipid core.

Radiolucent findings of coronary angiogram are believed to usually represent intracoronary thrombus, but in the present case, were atheromatous plaque with a large lipid core. A 62-year-old man who suffered from an inferior acute myocardial infarction was admitted to hospital 6 h after onset. The first cine angiograms showed TIMI-1 flow in the distal-portion of the right coronary artery, so thrombectomy was initially carried out and TIMI-2 flow achieved. However, the radiolucent lesion did not disappear and so adjunctive mechanical dilatation of the lesion was prformed, which resulted in 'no-reflow' (TIMI-0). Finally, aspiration of the material from the stagnated lesion was attempted and immediately obtained TIMI-3 flow. The retrieved materials were macrophages (foam cells) and many cholesterol crystals, both of which are considered to be atheromatous gruel. Therefore, the sudden flow reduction following percutaneous transluminal coronary angioplasty was caused by mechanical disruption of an atheromatous plaque with a large lipid core.

Prediction of no-reflow phenomenon after successful percutaneous coronary intervention in patients with acute myocardial infarction: intravascular ultrasound findings.

Plaque characterization by intravascular ultrasound (IVUS) before percutaneous coronary intervention (PCI) was evaluated in 81 consecutive patients with acute myocardial infarction (AMI) to establish if IVUS can predict the occurrence of the 'no-reflow' phenomenon. Angiographic no-reflow was defined as TIMI flow grade 1 or 2 without any mechanical obstruction in the epicardial artery. Patients were divided into 2 groups according to the post-PCI angiograms: normal flow (group R, n=60) and no-reflow (group NR, n=21). Although the incidence of either soft or noncalcified plaque was not statistically different between the groups, positive vessel remodeling was more frequent in group NR than in group R (57.1% vs 31.6%, p<0.05). Lipid core was also more frequently found in group NR than in group R (61.9% vs 25.0%, p<0.01). Positively remodeled vessels with lipid-rich plaques as characterized by IVUS before PCI predicted the occurrence of angiographic no reflow with a sensitivity of 43% and a specificity of 60%.