Thickness-Dependence Electrical Characterization of the One-Dimensional van der Waals TaSe3 Crystal

Needle-like single crystalline wires of TaSe3 were massively synthesized using the chemical vapor transport method. Since the wedged-shaped single TaSe3 molecular chains were stacked along the b-axis by weak van der Waals interactions, a few layers of TaSe3 flakes could be easily isolated using a typical mechanical exfoliation method. The exfoliated TaSe3 flakes had an anisotropic planar structure, and the number of layers could be controlled by a repeated peeling process until a monolayer of TaSe3 nanoribbon was obtained. Through atomic force and scanning Kelvin probe microscope analyses, it was found that the variation in the work function with the thickness of the TaSe3 flakes was due to the interlayer screening effect. We believe that our results will not only help to add a novel quasi-1D block for nanoelectronics devices based on 2D van der Waals heterostructures, but also provide crucial information for designing proper contacts in device architecture.

Remote Preconditioning on Rat Hepatic Ischemia-Reperfusion Injury Downregulated Bax and Cleaved Caspase-3 Expression

OBJECTIVE

Hepatic ischemia-reperfusion injury (IRI) is considered a major cause of hepatic damage in liver surgery. The aim of this study was to investigate the effect of the remote ischemic perconditioning method on hepatic IRI in a rat model.

METHODS

Seventeen rats underwent hepatic IRI for 30 minutes followed by reperfusion, and were divided into 3 groups: group I, only hepatic IRI (n = 5); group II, hepatic IRI with remote perconditioning (n = 7); and group III, hepatic IRI with remote postconditioning (n = 5).

RESULTS

For Bax/β-actin, mean values of the 3 groups (±standard deviation) were 1.29 ± 0.26 (group I), 0.89 ± 0.15 (group II), and 1.02 ± 0.23 (group III). The level of Bax/β-actin in group II was significantly lower than in group I (P < .01). The cleaved Caspase-3/β-actin ratio for groups I, II, and III was 0.93 ± 0.22, 0.46 ± 0.16, and 0.63 ± 0.22, respectively. The level of cleaved Caspase-3/β-actin in groups II and III were significantly lower than in group I (P < .01 and P < .05, respectively). The Bcl-2/β-actin ratio for groups I, II, and III was 1.01 ± 0.09, 1.19 ± 0.39, and 1.20 ± 0.12, respectively. However, there were no significant difference between groups II and III and group I.

CONCLUSIONS

The remote perconditioning on rat hepatic IRI downregulated the Bax and cleaved Caspase-3 expression.

Use of antimicrobial agents in aquaculture

The aquaculture industry has grown dramatically, and plays an important role in the world's food supply chain. Antimicrobial resistance in bacteria associated with food animals receives much attention, and drug use in aquaculture is also an important issue. There are many differences between aquatic and terrestrial management systems, such as the methods used for administration of drugs. Unique problems are related to the application of drugs in aquatic environments. Residual drugs in fish products can affect people who consume them, and antimicrobials released into aquatic environments can select for resistant bacteria. Moreover, these antimicrobial-resistant bacteria, or their resistance genes, can be transferred to humans. To decrease the risks associated with the use of antimicrobials, various regulations have been developed. In addition, it is necessary to prevent bacterial diseases in aquatic animals by vaccination, to improve culture systems, and to monitor the amount of antimicrobial drugs used and the prevalence of antimicrobial-resistant bacteria.

Mid-infrared photothermal heterodyne spectroscopy in a liquid crystal using a quantum cascade laser

We report a technique to measure the mid-infrared photothermal response induced by a tunable quantum cascade laser in the neat liquid crystal 4-octyl-4'-cyanobiphenyl (8CB), without any intercalated dye. Heterodyne detection using a Ti:sapphire laser of the response in the solid, smectic, nematic and isotropic liquid crystal phases allows direct detection of a weak mid-infrared normal mode absorption using an inexpensive photodetector. At high pump power in the nematic phase, we observe an interesting peak splitting in the photothermal response. Tunable lasers that can access still stronger modes will facilitate photothermal heterodyne mid-infrared vibrational spectroscopy.

Multi walled carbon nanotube nanocomposites with biodegradable poly(butylene succinate) and their physical characteristics

In order to examine the influence of multi walled carbon nanotube (MWNT) on physical properties of its biodegradable polymer nanocomposite, biodegradable poly(buthylene succinate) (PBS), which was synthesized from diols and dicarboxylic acids, and MWNT nanocomposites were prepared via a melt-mixing method using a co-rotating intermeshing twin screw extruder. Microstructure of the PBS/MWNT nanocomposites and MWNT were investigated via both scanning electron microscopy and transmission electron microscopy. Their rheological properties were also characterized via rotation and oscillation tests using a rotational rheometer with parallel-plate geometry. It was found that shear viscosity, storage modulus and loss modulus of the nanocomposites examined by a rotational rheometer increased with the MWNT content. Especially their sharp increase for MWNT content of ca. 2.0 wt% was observed, indicating its percolation threshold from the rheological viewpoint which was higher than its electrical percolation threshold (1.0 wt%).

Long-term follow-up after deferring angioplasty in asymptomatic patients with moderate noncritical in-stent restenosis

BACKGROUND

Many patients with in-stent restenosis (ISR) are angina-free, but the optimal treatment for these patients remains uncertain.

HYPOTHESIS

In cases with asymptomatic moderate noncritical ISR. deferral of the intervention may be safe and associated with favorable clinical outcome.

METHODS

We evaluated the long-term clinical outcome of asymptomatic patients (Group 1, n = 98) with moderate noncritical ISR (< 70% diameter stenosis) after intervention was deferred, and compared it with that of patients (Group 2, n = 655) without restenosis. After repeat angioplasty was deferred, all patients were treated medically and later underwent angioplasty only in the case of clinical recurrence.

RESULTS

Baseline characteristics were similar between the two groups. Clinical follow-up was available in all patients at 26.3+/-15.9 months. Twenty patients died during the follow-up: 1 in Group 1 and 19 in Group 2. Target lesion revascularization was performed in 3 patients in Group 1 and 11 patients in Group 2 during follow-up (p = NS), and new lesion revascularization in 2 patients in Group 1 and 27 patients in Group 2 (p = NS). Event-free survival rate (cardiac death, nonfatal myocardial infarction, repeat revascularization) was 86.7+/-6.1% in Group 1 and 84.8+/-2.2% in Group 2 at the end of follow-up (p = NS). Major adverse cardiac events were only associated with the presence of diabetic mellitus (hazards ratio 2.65, 95% confidence interval [CI] 1.48-4.73, p<0.01). The percentage of patients receiving antianginal medication was similar between the two groups at the end of the study (p = NS).

CONCLUSIONS

Asymptomatic patients with moderate noncritical ISR have a good prognosis and similar clinical outcome as those without ISR, suggesting that it may be safe to defer repeat angioplasty in these patients until angina recurrence.

Immediate and late clinical and angiographic outcomes after GFX coronary stenting: is high-pressure balloon dilatation necessary?

BACKGROUND

The GFX stent is a balloon-expandable stent made of sinusoidal element of stainless steel. The adjunct high-pressure balloon dilatations were usually recommended in routine stenting procedure.

HYPOTHESIS

The aim of this study was to evaluate the immediate and long-term clinical and angiographic outcomes and to investigate the necessity of high-pressure balloon dilatation during GFX stenting.

METHODS

In all, 172 consecutive patients underwent single 12 or 18 mm GFX stent implantation in 188 native coronary lesions. Two types of stenting technique were used: (1) stent size of a final stent-to-artery ratio of 1:1 (inflation pressure > 10 atm, high-pressure group), and (2) stent size of 0.5 mm bigger than reference vessel (inflation pressure < or = 10 atm, low-pressure group). The adjunct high-pressure balloon dilatations were performed only in cases of suboptimal results.

RESULTS

The adjunct high-pressure balloon dilatation was required in 11 of 83 lesions (13%) in the high-pressure group and in 7 of 105 lesions (7%) in the low-pressure group (p = 0.203). Procedural success rate was 100%. There were no significant differences of in-hospital and long-term clinical events between the two groups. The overall angiographic restenosis rate was 17.7%; 18.4% in the high-pressure group and 17.1% in the low-pressure group (p = 0.991).

CONCLUSIONS

The GFX stent is a safe and effective device with a high procedural success rate and favorable late clinical outcome for treatment of native coronary artery disease. Further randomized trials may be needed to compare stenting techniques in GFX stent implantation.

Rescue use of abciximab improves regional left ventricular function after early incomplete reperfusion in acute myocardial infarction

BACKGROUND

Abciximab was shown to have important beneficial effects beyond the maintenance of epicardial coronary artery patency. However, it remains uncertain whether abciximab may lead to a better functional outcome in patients with acute myocardial infarction (AMI) and with incomplete reperfusion after primary angioplasty (PA).

HYPOTHESIS

The study aimed to evaluate whether rescue use of abciximab may lead to a better functional outcome in such patients.

METHODS

The study included 25 patients with first AMI who met the following criteria: (1) total occlusion of the infarct-related artery, (2) PA within 12 h of symptom onset, (3) postprocedural diameter stenosis < 30%, and final Thrombolysis in Myocardial Infarction (TIMI) flow grade 2. Echocardiographic examination was performed before and on Days 7 and 30 after PA. The study population was divided into two groups: Group 1 (usual care, n = 13) and Group 2 (rescue use of abciximab, n = 12). Baseline characteristics were similar between the two groups.

RESULTS

Peak level of creatine kinase was higher in Group 1 than in Group 2 (5,800+/-2,700 vs. 3,800+/-2,000 U/I, p < 0.05). At 1 month follow-up, infarct zone wall motion score index (2.71+/-0.26 vs. 2.05+/-0.63, p < 0.01) and left ventricular (LV) volume indices were smaller in Group 2 than in Group 1, whereas LV ejection fraction was higher in Group 2 than in Group 1 (52.1+/-7.8 vs. 42.1+/-6.4, p < 0.01). At 1-month, abciximab was the only independent predictor of wall motion recovery index by multiple regression analysis.

CONCLUSIONS

Rescue use of abciximab may reduce the infarct size in patients with AMI and TIMI grade 2 flow after PA, which may improve the recovery of regional LV function.

Structure determination of new analogues of vardenafil and sildenafil in dietary supplements

New analogues of vardenafil and sildenafil illegally added to dietary supplements were detected by high-performance liquid chromatography (HPLC) analysis with a photodiode array detector (PDA). These compounds were isolated and their structures elucidated by mass spectrometry (MS), infrared (IR) spectroscopy, one- and two-dimensional nuclear magnetic resonance (NMR). One of the new analogues given the trivial name pseudovardenafil (compound 1) was structurally elucidated and shown to be 1-[[3-(1,4-dihydro-5-methyl-4-oxo-7-propylimidazo[5,1-f][1,2,4]triazin-2-yl)-4-ethoxyphenyl]sulfonyl]-piperidine. It was a vardenafil analogue isolated from a dietary supplement capsule. Compared with vardenafil, the piperidine ring was substituted for the ethylpiperazine group. The second new analogue, trivially named hydroxyhongdenafil (compound 2), was separated from bulk powder used as a raw material for a dietary supplement. The piperazine and phenyl groups were connected through an acetyl group instead of a sulfonyl group, and hydroxyethylpiperazine was substituted for the methylpiperazine of sildenafil. It was structurally elucidated as 5-[2-ethoxy-5-[[4-(2-hydroxyethyl)-1-piperazinyl]acetyl]phenyl]-1,4-dihydro-1-methyl-3-propyl-7H-pyrazolo[4,3-d]pyrimidin-7-one.

Myocardial enhancement pattern in patients with acute myocardial infarction on two-phase contrast-enhanced ECG-gated multidetector-row computed tomography

AIM

To evaluate the myocardial enhancement pattern of the left ventricle on two-phase contrast-enhanced electrocardiogram (ECG)-gated multidetector computed tomography (MDCT) images in patients with acute myocardial infarction (AMI).

METHODS

Two-phase contrast-enhanced ECG-gated MDCT examinations were performed in 16 patients with AMI. The presence, location and pattern of myocardial enhancement were evaluated. MDCT findings were compared with the catheter angiographic results.

RESULTS

Subendocardial (n = 9) or transmural (n = 6) area of early perfusion defects of the myocardium was detected in 15 of 16 patients (94%) on early-phase CT images. Variable delayed myocardial enhancement patterns on late-phase CT images were observed in 12 patients (75%): (1) subendocardial residual perfusion defect and subepicardial late enhancement (n = 6); (2) transmural late enhancement (n = 1); (3) isolated subendocardial late enhancement (n=1); and (4) isolated subendocardial residual perfusion defect (n = 2). On catheter angiography, 14 of 15 corresponding coronary arteries showed significant stenosis.

CONCLUSION

Variable abnormal myocardial enhancement pattern was seen on two-phase, contrast-enhanced ECG-gated MDCT in patients with AMI. Assessment of myocardial attenuation on CT angiography gives additional information of the location and extent of infarction.

Survey of nitrate and nitrite contents of vegetables grown in Korea

A scientific basis for the evaluation of the risk to public health arising from excessive dietary intake of nitrate in Korea is provided. The nitrate () and nitrite () contents of various vegetables (Chinese cabbage, radish, lettuce, spinach, soybean sprouts, onion, pumpkin, green onion, cucumber, potato, carrot, garlic, green pepper, cabbage and Allium tuberosum Roth known as Crown daisy) are reported. Six hundred samples of 15 vegetables cultivated during different seasons were analysed for nitrate and nitrite by ion chromatography and ultraviolet spectrophotometry, respectively. No significant variance in nitrate levels was found for most vegetables cultivated during the summer and winter harvests. The mean nitrates level was higher in A. tuberosum Roth (5150 mg kg(-1)) and spinach (4259 mg kg(-1)), intermediate in radish (1878 mg kg(-1)) and Chinese cabbage (1740 mg kg(-1)), and lower in onion (23 mg kg(-1)), soybean sprouts (56 mg kg(-1)) and green pepper (76 mg kg(-1)) compared with those in other vegetables. The average nitrite contents in various vegetables were about 0.6 mg kg(-1), and the values were not significantly different among most vegetables. It was observed that nitrate contents in vegetables varied depending on the type of vegetables and were similar to those in vegetables grown in other countries. From the results of our studies and other information from foreign sources, it can be concluded that it is not necessary to establish limits of nitrates contents of vegetables cultivated in Korea due to the co-presence of beneficial elements such as ascorbic acid and alpha-tocopherol which are known to inhibit the formation of nitrosamine.

[Stent coated with bovine pericardium: in vitro evaluation, in animals, and initial results in humans]

Covering a stent with a membrane (stent graft) allows treatment of diverse coronary abnormalities such as aneurysms, rupture and fistulas (which, until recently, required surgical therapy). A stent graft could also reduce embolic complications associated with angioplasty of saphenous vein grafts. The objective of this study is to evaluate bovine pericardium as a graft for conventional stents. In vitro testing of the bovine pericardium disclosed an elasticity of 15% and a resistance to rupture of 0.22 kg/mm2, well above the pressure commonly used during stent deployment. In 18 pigs, 29 of 32 (90.63%) attempts to implant stent grafts were successful. Histology of acute porcine studies revealed correct apposition of the stent graft to the vessel wall, subacute and chronic (10 days and 1 month) samples showed adequate endothelization and exclusion of proliferative media. Twenty stents were placed in 15 patients with a 100% success rate. Seven patients had coronary aneurysms and in all a complete exclusion of the aneurysm was obtained without complications. Fourteen patients have a follow-up of 6 or more months with evidence of clinical restenosis in 2 (14.28%), whereas angiographic follow-up in 9 patients, which included the 2 cases with recurrent angina, evidenced restenosis in 3 of 14 stents (21.4%), two of which were overlapped in the LAD of one patient and one corresponded to a series of 9 stents (in 5 patients) placed in saphenous vein grafts. It is concluded that bovine pericardium is a suitable material for stent-grafts and its efficacy to seal coronary aneurysms was demonstrated. These results warrant a larger comparative study to better define its restenosis rate and further delineate its usefulness in the treatment of diseased saphenous vein grafts.

Intravascular ultrasound analysis of beta radiation therapy for diffuse in-stent restenosis to inhibit intimal hyperplasia

We evaluated the efficacy of beta-radiation therapy ((188)Re-MAG(3)) to inhibit intimal hyperplasia (IH) in diffuse in-stent restenosis by intravascular ultrasound (IVUS) analysis in 50 patients. Nine patients who did not agree with radiation therapy, and therefore underwent rotational atherectomy and balloon angioplasty for diffuse in-stent restenosis in the same study period, were selected for control groups. Serial IVUS comparisons were available in 44 of 50 patients with radiation therapy and 7 of 9 control patients. At 6-month follow-up, there was less significant increase of IH area in patients with radiation therapy than in control patients (Delta IH area = 0.1 +/- 0.8 mm(2) vs. 2.6 +/- 1.8 mm(2), P > 0.001 in mean values, and 0.6 +/- 1.4 mm(2) vs. 2.9 +/- 2.1 mm(2), P = 0.026 in values of follow-up lesion site, respectively). In conclusion, beta-radiation therapy might be an effective treatment modality to inhibit intimal hyperplasia in patients with diffuse in-stent restenosis.

Elective stenting of unprotected left main coronary artery stenosis: effect of debulking before stenting and intravascular ultrasound guidance

OBJECTIVES

We sought to evaluate: 1) the long-term outcomes of 127 selected patients receiving unprotected left main coronary artery (LMCA) stenting; and 2) the impact of the debulking procedure before stenting and intravascular ultrasound (IVUS) guidance on their clinical outcomes.

BACKGROUND

The long-term safety of stenting of unprotected LMCA stenoses has not been established yet.

METHODS

A total of 127 consecutive patients with unprotected LMCA stenosis and normal left ventricular function were treated by elective stenting. The long-term outcomes were evaluated between two groups: IVUS guidance (n = 77) vs. angiographic guidance (n = 50); and debulking plus stenting (debulking/stenting; n = 40) vs. stenting only (n = 87).

RESULTS

Angiographic restenosis was documented in 19 (19%) of 100 patients. The lumen diameter after stenting was significantly larger in IVUS-guided group (p = 0.003). The angiographic restenosis rate was significantly lower in the debulking/stenting group (8.3% vs. 25%, p = 0.034). The reference artery size was the only independent predictor of angiographic restenosis. During follow-up (25.5 +/- 16.7 months), there were four deaths, but no nonfatal myocardial infarctions occurred. The survival rate was 97.0 +/- 1.7% at two years.

CONCLUSIONS

These data suggest that stenting of unprotected LMCA stenosis might be associated with a favorable long-term outcome in selected patients. Guidance with IVUS may optimize the immediate results, and debulking before stenting seems to be effective in reducing the restenosis rate. However, we need a large-scale, randomized study.

Clinical characteristics of constrictive pericarditis diagnosed by echo-Doppler technique in Korea

A retrospective analysis of clinical data of 71 patients with constrictive pericarditis (CP) diagnosed by echo-Doppler technique (mean age, 49+/-17) was done. In 27 patients (38%), the etiology was unknown, and the three most frequent identifiable causes were tuberculosis (23/71, 32%), cardiac surgery (8/71, 11%), and mediastinal irradiation (6/71, 9%). Pericardiectomy was performed in 35 patients (49%) with a surgical mortality of 6% (2/35), and 11 patients (15%, 11/ 71) showed complete resolution of constrictive physiology with medical treatment. Patients with transient CP were characterized by absence of pericardial calcification, shorter symptom duration, and higher incidence of fever, weight loss, and tuberculosis. The 5-yr survival rates of patients with transient CP and those undergoing pericardiectomy were 100% and 85+/-6%, respectively, which were significantly higher than that of patients without undergoing pericardiectomy (33+/-17%, p=0.0083). Mediastinal irradiation, higher functional class, low voltage in ECG, low serum albumin, and old age were the independent variables associated with a higher mortality. Tuberculosis is still the most important etiology of CP in Korea, and not infrequently, it may cause transient CP. Early diagnosis and decision-making using follow-up echocardiography are crucial to improve the prognosis of patients with CP.

Paclitaxel-coated Gianturco-Roubin II (GR II) stents reduce neointimal hyperplasia in a porcine coronary in-stent restenosis model

BACKGROUND

Drug-coated stents may treat both mechanisms of restenosis, namely, geometric remodeling and neointimal hyperplasia. Paclitaxel, an antimicrotubule agent, has been shown to inhibit smooth muscle cell proliferation and migration, and may be an excellent candidate for local elution from a stent platform.

METHODS

To study the antirestenosis effects of drug-coated stents, we impregnated paclitaxel (175-200 microg/stent with programmed elution over 6 months) on Gianturco-Roubin II (GR II) stents. These stents and control stents without drugs were implanted in porcine coronary arteries (stent/artery approx. 1.1) and evaluated 4 weeks later.

RESULTS

The vessel size and the stent-to-artery ratio were similar between the groups. However, at 4 weeks, the paclitaxel group had significantly reduced in-stent restenosis compared with the controls (51 +/- 27 versus 27 +/- 27% diameter stenosis, P < 0.05 and 669 +/- 357 versus 403 +/- 197 microm neointimal thickness, P < 0.05). This study further confirmed the biocompatibility of the polymer, with no foreign body reaction in any of the groups.

CONCLUSIONS

This study shows that the paclitaxel-coated stents significantly reduced in-stent restenosis without eliciting inflammation.

Treatment of diffuse in-stent restenosis with rotational atherectomy followed by radiation therapy with a rhenium-188-mercaptoacetyltriglycine-filled balloon

OBJECTIVES

This study was done to evaluate the feasibility and efficacy of beta-radiation therapy with a rhenium-188-mercaptoacetyltriglycine ((188)Re-MAG(3))-filled balloon after rotational atherectomy for diffuse in-stent restenosis (ISR).

BACKGROUND

Rotational atherectomy has been shown to be safe and efficient for the treatment of ISR, but the recurrence rate is still high. Intracoronary beta-irradiation after rotational atherectomy may be a reasonable approach to prevent recurrent ISR.

METHODS

Fifty consecutive patients with diffuse ISR (length >10 mm) in native coronary arteries underwent rotational atherectomy and adjunctive balloon angioplasty, followed by beta-irradiation using a (188)Re-MAG(3)-filled balloon catheter. The radiation dose was 15 Gy at a depth of 1.0 mm into the vessel wall.

RESULTS

The mean lengths of the lesion and irradiated segment were 25.6 +/- 12.7 mm and 37.6 +/- 11.2 mm, respectively. Radiation was delivered successfully to all patients, with a mean irradiation time of 201.8 +/- 61.7 s. No adverse event, including myocardial infarction, death or stent thrombosis, occurred during the follow-up period (mean 10.3 +/- 3.7 months), and nontarget vessel revascularization was needed in one patient. The six-month binary angiographic restenosis rate was 10.4%, and the loss index was 0.17 +/- 0.31.

CONCLUSIONS

Beta-irradiation using a (188)Re-MAG(3)-filled balloon after rotational atherectomy is safe and feasible in patients with diffuse ISR, and it may improve their clinical and angiographic outcomes. Further prospective, randomized trials are warranted to evaluate the synergistic effect of debulking and irradiation in patients with diffuse ISR.

Determinants and prognostic implications of terminal QRS complex distortion in patients treated with primary angioplasty for acute myocardial infarction

Terminal QRS complex distortion on admission has an impact on a patient's prognosis after primary angioplasty for acute myocardial infarction (AMI). We evaluated the determinants and prognostic significance of terminal QRS complex distortion in 153 consecutive patients with AMI after primary angioplasty. The study population was divided into 2 groups according to the presence (group I, n = 41) or absence (group II, n = 112) of terminal QRS complex distortion. The primary end points were the occurrence, within 6 weeks after AMI, of death, nonfatal reinfarction, or congestive heart failure. Baseline characteristics were similar between the 2 groups. However, patients in group I had higher peak levels of serum creatine kinase than those in group II (5,100 +/- 3,100 vs 3,000 +/- 1,800 U/L, respectively, p <0.01). The rate of angiographic no-reflow (Thrombolysis In Myocardial Infarction flow grade < or =2) was 31.7% in group I and 10.7% in group II (p <0.01). The predischarge left ventricular ejection fraction was 45.0 +/- 12.0% in group I and 54.0 +/- 8.0% in group II (p <0.01). Multivariate analysis identified the pressure-derived fractional collateral flow index and the culprit lesion in the left anterior descending coronary artery as independent determinants of the terminal QRS complex distortion. No patients died during 6 weeks of follow-up. The 2 groups were similar for life-threatening arrhythmia or reinfarction. However, there were more patients in group I than in group II with congestive heart failure (26.8% vs 5.4%, respectively, p <0.01) or who reached the primary end points (29.3% vs 5.4%, respectively, p <0.01). In conclusion, terminal QRS complex distortion on admission is associated with poor clinical outcome after primary angioplasty for AMI, and collateral flow may have a major influence on terminal QRS complex distortion during AMI.

Are we making progress with percutaneous saphenous vein graft treatment? A comparison of 1990 to 1994 and 1995 to 1998 results

OBJECTIVES

We sought to determine whether strategies to reduce procedural distal embolization and late repeat revascularization have resulted in more favorable outcomes after saphenous vein graft (SVG) angioplasty.

BACKGROUND

Angioplasty of SVG lesions has been associated with frequent procedural and late cardiac events. Therefore, evolving strategies have been attempted to improve outcomes after SVG angioplasty.

METHODS

We compared our earlier experience (1990 to 1994) of 1,055 patients with 1,412 SVG lesions with a recent group (1995 to 1998) of 964 patients with 1,315 lesions.

RESULTS

Baseline characteristics were similar between the groups. However, there were significantly more unfavorable lesion characteristics (older, longer and significantly more degenerated SVGs) in the recent series. Between the two periods, there was decreased use ofatheroablative devices, whereas stent use increased. The procedural success rates (96.6% vs. 96.1%) were similar. However, one-year outcome (event-free survival) was significantly improved in the more recent experience (70.7% vs. 59.1%, p < 0.0001), especially late mortality (6.1% vs. 11.3%, p < 0.0001). Multivariate analysis showed stent use to be the only protective variable for both periods.

CONCLUSIONS

This study shows that despite higher risk lesions, strategies to reduce distal embolization have maintained high procedural success. Late cardiac events, including mortality, have also been substantially reduced.

Prognostic significance of cerebral metabolic abnormalities in patients with congestive heart failure

BACKGROUND

Cerebral metabolic abnormalities were proposed as a potential marker of disease severity in congestive heart failure (CHF), but their prognostic significance remains uncertain.

METHODS AND RESULTS

We investigated the prognostic value of cerebral metabolic abnormalities in 130 consecutive patients with advanced CHF (100 men aged 42.6+/-11.9 years; left ventricular ejection fraction, 22.2+/-6.2%). Proton magnetic resonance spectroscopy data were obtained from localized regions ( approximately 8 mL) of the occipital gray matter and the parietal white matter. The primary end point was the occurrence of death after the proton magnetic resonance spectroscopy. During follow-up (18.5+/-14.4 months), 21 patients died and 15 underwent urgent heart transplantation. In the Cox proportional model, occipital metabolites (N-acetylaspartate, creatine, choline, and myoinositol), parietal N-acetylaspartate level, and the duration of CHF symptoms (>12 months) were validated as univariate predictors of death. In multivariate Cox analyses, however, the occipital N-acetylaspartate level was an independent predictor of death (hazard ratio, 0.52; 95% CI, 0.41 to 0.67; P<0.001). An analysis with respect to the combined end point of death or urgent transplantation showed similar results. The best cutoff value (9.0 mmol/kg) for occipital N-acetylaspartate level had 75% sensitivity and 67% specificity to predict mortality.

CONCLUSIONS

The occipital N-acetylaspartate level is a powerful and independent predictor of CHF mortality, suggesting that cerebral metabolic abnormalities may be used as a new prognostic marker in the assessment of patients with CHF.

Primary hyperparathyroidism and acute pancreatitis during the third trimester of pregnancy

The simultaneous occurrence of maternal primary hyperparathyroidism (PHPT) and acute pancreatitis during pregnancy is very rare. We report a case of concurrent PHPT and pancreatitis during the third trimester of pregnancy. A summary of the relevant literature regarding the clinical course and recommended management in relation to this case is also presented.

Six-month angiographic follow-up after intravascular ultrasound-guided stenting of infarct-related artery: comparison with non-infarct-related artery

BACKGROUND

Compared with balloon angioplasty, stenting has been established as an effective treatment modality to reduce restenosis in patients with acute myocardial infarction. However, the immediate results that predict favorable long-term outcomes in the acute infarct stenting are unknown. Therefore, we evaluated long-term outcomes of stenting for infarct-related artery (IRA) lesions by using intravascular ultrasound (IVUS) compared with that of stenting for non-IRA lesions.

METHODS

IVUS-guided coronary stenting was successfully performed in 510 native coronary lesions (105 IRA vs 405 non-IRA). A 6-month follow-up angiogram was performed in 419 (82.2%) lesions: 87 (82.9%) IRA lesions and 332 (82.0%) non-IRA lesions. Coronary stenting on the IRA lesions was successfully performed within 7 to 10 days after onset of infarction in 42 patients and within 12 hours in 45 patients. Results were evaluated by clinical, angiographic, and IVUS methods.

RESULTS

There were no significant differences in clinical and angiographic variables between the two groups. IVUS variables including reference vessel area and minimal stent area were also similar between the two groups. There was no significant difference in angiographic restenosis rate between the two groups in cases of minimal stent area > or = 7 mm(2): 12.8% (6 of 47) in IRA versus 19.1% (33 of 173) in non-IRA lesions (P = .315). However, the angiographic restenosis rate in cases of minimal stent area <7 mm(2) was 50% (20 of 40) in IRA lesions versus 31.5% (50 of 159) in non-IRA lesions (P = .028).

CONCLUSIONS

Angiographic restenosis is significantly higher in stenting for IRA lesions compared with that for non-IRA lesions in cases of minimal stent area < 7 mm(2).

Determinants and prognostic significance of spontaneous coronary recanalization in acute myocardial infarction

Spontaneous recanalization (SR) occurs after the onset of acute myocardial infarction (AMI), but its clinical significance in the reperfusion era remains uncertain. We evaluated the determinants and prognostic significance of SR in 196 consecutive patients with AMI who underwent primary angioplasty at our institution. The study population was divided into 2 groups according to the presence (group I, n = 44) or absence (group II, n = 152) of SR (Thrombolysis In Myocardial Infarction [TIMI] anterograde > or = 2 flow on the preintervention angiogram). The primary end point was the occurrence, within 6-weeks after AMI, of death, nonfatal reinfarction, and congestive heart failure. Baseline characteristics were similar between the 2 groups. Peak levels of creatine kinase were lower in group I than in group II (2,500 +/- 1,800 vs 4,000 +/- 2,900 U/L, respectively, p < 0.05). The rate of TIMI flow grade 3 after intervention was higher in group I than in group II (93.2% vs 79.6%, respectively, p < 0.05), and patients in group I had a faster corrected TIMI frame count than those in group II (22.7 +/- 12.4 vs 30.3 +/- 22.8, respectively, p < 0.05). Preinfarction angina (odds ratio [OR] 2.18, 95% confidence interval [CI] 1.10 to 4.33, p < 0.05), heavy thrombi (OR 0.10, 95% CI 0.01 to 0.74, p < 0.05), and good angiographic collaterals (OR 0.12, 95% CI 0.02 to 0.89, p < 0.05) were independent predictors of SR. Death, reinfarction, and severe arrhythmia were not different between the 2 groups. However, heart failure occurred more frequently in group II than in group I (15.1% vs 2.3%, respectively, p < 0.05). The primary end point was also significantly lower in group I than in group II (4.5% vs 18.4%, respectively, p < 0.05). In conclusion, SR in AMI is associated with faster coronary flow, smaller infarct size, and a better clinical outcome after primary angioplasty.

Comparison of endocardial electromechanical mapping with radionuclide perfusion imaging to assess myocardial viability and severity of myocardial ischemia in angina pectoris

The assessment of left ventricular electromechanical activity using a novel, nonfluoroscopic 3-dimensional mapping system demonstrates considerable differences in electrical and mechanical activities within regions of myocardial infarction or ischemia. We sought to determine whether these changes correlate with indexes of myocardial perfusion, viability, or ischemia. A 12-segment comparative analysis was performed in 61 patients (45 men, 61 +/- 12 years old) with class III to IV angina, having reversible and/or fixed myocardial perfusion defects on single-photon emission computed tomographic perfusion imaging. A dual-isotope protocol was used, consisting of rest and 4-hour redistribution thallium images followed by adenosine technetium-99m sestamibi imaging. Average rest endocardial unipolar voltage (UpV) and local shortening (LS) mapping values were compared with visually derived perfusion scores. There was gradual and proportional reduction in regional UpV and LS in relation to thallium-201 uptake score at rest (p = 0.0001 and p = 0.0002, respectively) and redistribution studies (p = 0.0001 and p = 0.003, respectively). UpV > or = 7.4 mV and LS > or = 5.0% had a sensitivity of 78% and 65%, respectively, with a specificity of 68% and 67% for detecting viable myocardium. UpV values of 12.3 and 5.4 mV had 90% specificity and sensitivity, respectively, to predict viable tissue. UpV, but not LS, values differentiated between normal segments and those with adenosine-induced severe perfusion defects (11.8 +/- 5.3 vs 8.8 +/- 4.1 mV, p = 0.005). Catheter-based left ventricular assessment of electromechanical activity correlates with the degree of single-photon emission computed tomographic perfusion abnormality and can identify myocardial viability with a greater accuracy than myocardial ischemia.

Automation of the synthesis of highly concentrated 188Re-MAG3 for intracoronary radiation therapy

We have developed an efficient method and an automated synthetic system for the preparation of highly concentrated 188Re-MAG3. Routine production of 188Re-MAG3 for use in intracoronary radiation therapy was performed by compressed air driven semi-automated shielded system. 188Re-MAG3 was prepared with a commercial kit and reducing agents, purified and concentrated by C18 Sep-Pak cartridges to desired radioactivity and volume. Using this automated system, reproducible radiolabeling yields of 80-85% were obtained.

Influence of gender on early and one-year clinical outcomes after saphenous vein graft stenting

Compared with men, women may have a worse prognosis after native coronary revascularization. However, the influence of gender on clinical outcomes after saphenous vein graft (SVG) stenting is unknown. The purpose of this study was to compare early and 1-year clinical outcomes between men and women after stent implantation in SVG. A total of 1,199 consecutive patients with 1,858 SVG lesions were studied. Procedural success, in-hospital events, and late clinical outcomes were compared between men (n = 951) and women (n = 248). Overall procedural success was similar between men and women (97% vs 96%, p = NS). However, in-hospital (3.2% vs 1.6%, p = 0.07) and 30-day cumulative (4.4% vs 1.9%, p = 0.02) mortality rates were higher in women than in men. In addition, women had a higher incidence of vascular complications (12% vs 7.3%, p = 0.006) and postprocedural acute renal failure (8.1% vs 4%, p = 0.02). At 1-year follow-up, mortality was 13% in women and 11% in men (p = NS) and target lesion revascularization was 18% versus 23%, respectively (p = NS). By multivariate regression analysis, independent correlates of in-hospital mortality were female gender (odds ratio [OR] 3.6, confidence interval [CI] 1.0 to 12.5, p = 0.05) and left ventricular ejection fraction (OR 0.9, CI 0.9 to 1.0, p = 0.01). Female gender was found to predict 30-day mortality (OR 2.5, CI 1.1 to 5.5, p = 0.02). The sole predictor of 1-year mortality was diabetes mellitus (OR 1.6, CI 1.1 to 2.3, p = 0.01). This study shows that women compared with men treated with stent implantation in SVG lesions have (1) a trend toward higher in-hospital mortality, (2) higher risk of 30-day mortality, (3) increased incidence of vascular complications and postprocedure acute renal failure, and (4) similar 1-year clinical outcome.

Effects of stent design on side branch occlusion after coronary stent placement

This study was performed to assess the immediate and long-term patency of stent-associated side branches (SB) according to the types of stent. A total of 314 patients with 332 lesions (CrossFlex stent 86, NIR 100, GFX 146) had 365 SB (>1 mm) covered by coronary stents. Side branch occlusion (SBO) occurred in 7.7% of CrossFlex stent, in 10.5% of NIR stent and in 8.8% of GFX stent (P = NS). SBO primarily occurred in SB with ostial disease, and the presence of SB ostial disease was the only independent predictors of SBO after stenting (OR 22.1, 95% CI 9.47-51.49, P < 0.001). At 6 months follow-up, 11 of 31 SBO regained the patency, but the remaining SB had persistent SBO. Delayed SBO occurred in 8 SB, being associated with the presence of SB ostial disease and in-stent restenosis. In conclusions, SBO was not associated with the types of stent design, but with the SB lesion morphology.

Determinants of coronary blood flow following primary angioplasty for acute myocardial infarction

The aim of this study was to evaluate determinants of coronary blood flow following primary angioplasty (PA) in acute myocardial infarction (AMI). The corrected TIMI (thrombolysis in myocardial infarction) frame count and the TIMI flow grade were used as indexes of coronary blood flow, and its determinants were examined in 115 consecutive AMI patients who underwent PA (pain onset </= 12 hr). The following were validated as univariate predictors of slower corrected TIMI frame count: a lower pressure-derived farctional collateral flow (PDCF) index (P < 0.01), poor angiographic collaterals (P < 0.01), TIMI flow 0, 1 before PA (P < 0.05), and the presence of heavy thrombi (P < 0.01). The PDCF index and the presence of heavy thrombi were independent predictors of the corrected TIMI frame count. Likewise, the PDCF index (chi(2) = 12.9; P < 0.01) and the presence of heavy thombi (chi(2) = 11.4; P < 0.01) were independent predictors of TIMI 3 flow. In conclusion, collateral flow and the presence of thrombi are major determinants of coronary blood flow after PA in AMI.

Assessing a strategy of initial stand-alone extractional atherectomy followed by staged stent placement in degenerated saphenous vein graft lesions

To assess whether a staged strategy (initial stand alone transluminal extraction atherectomy and coumadin therapy followed by stenting six weeks later) could reduce ischemic complications in degenerated saphenous vein graft (SVG) interventions, we studied 72 patients undergoing percutaneous interventions of degenerated SVG. Patients were divided into two groups; 28 were treated with a staged strategy (group I) and 44 with similar lesion characteristics were treated with a definitive initial procedure with transluminal extraction atherectomy +/- adjunctive balloon angioplasty and stenting (group II). Procedural success, major in-hospital complications (death, Q-wave myocardial infarction, and emergent coronary bypass surgery), and incidence of distal embolization were compared between the 2 groups. Procedural success was lower (92% vs 100%, p = 0.14) and major in-hospital complications were higher (0% vs 11%, p = 0.14) in group II. Distal embolization occurred in 11% of the patients in group I compared with 23% of the patients in group II (p = 0.19). At 6 week follow-up (group I), 9 patients (33%) had negative symptoms, 11 (41%) underwent stent implantation, 3 (11%) did not require any further therapy (without significant stenosis), and 4 (14%) had total occlusions. We therefore conclude that this staged strategy in degenerated SVG appears to reduce distal embolization but most importantly avoids major in-hospital complications, including any deaths either at the time of initial procedure or during the 6-week follow-up period.

Randomized comparison of coronary stenting with optimal balloon angioplasty for treatment of lesions in small coronary arteries

AIMS

Angioplasty of lesions in small coronary arteries remains a significant problem because of the increased risk of restenosis. The aim of this study was to compare the efficacy of elective coronary stent placement and optimal balloon angioplasty in small vessel disease.

METHODS

One hundred and twenty patients with lesions in small coronary arteries (de novo, non-ostial lesion and reference diameter <3 mm) were randomly assigned to either balloon angioplasty or elective stent placement (7-cell NIR stent). The primary end-point was restenosis at 6 months follow-up. Optimal balloon angioplasty was defined as diameter stenosis less than or = 30% and the absence of major dissection after the angioplasty, and crossover to stenting was allowed.

RESULTS

Baseline clinical and angiographic characteristics were similar in the two groups. Procedure was successful in all patients, and in-hospital events did not occur in any patient. However, 12 patients in the angioplasty group were stented because of suboptimal results or major dissection. Postprocedural lumen diameter was significantly larger in the stent group than in the angioplasty group (2.44 +/- 0.36 mm vs 2.14 +/- 0.36, P<0.05, respectively), but late loss was greater in the stent group (1.12 +/- 0.67 mm vs 0.63 +/- 0.48, P<0.01, respectively). The angiographic restenosis rate was 30.9% in the angioplasty group, and 35.7% in the stent group (P = ns). Clinical follow-up was available in all patients (15.9 +/- 5.7 months) and clinical events during the follow-up were similar in both groups.

CONCLUSIONS

These results suggest that optimal balloon angioplasty with provisional stenting may be a reasonable approach for treatment of lesions in small coronary arteries.

Long-term outcomes of minor dissection at the edge of stents detected with intravascular ultrasound

We evaluated the influences of minor edge dissections on late angiographic in-stent restenosis in 327 patients with 348 lesions (281 lesions without edge dissection and 67 lesions [19.3%] with edge dissection); the angiographic restenosis rate was 29.9% in the lesions with edge dissections versus 25.3% without edge dissections (p = 0.540). The minor non-flow-limiting dissections at the edge of stents may not be associated with the development of late angiographic in-stent restenosis.

Influence of diabetes mellitus on early and late clinical outcomes in saphenous vein graft stenting

OBJECTIVES

The purpose of this study was to compare early and late clinical outcomes in diabetic and nondiabetic patients after stent implantation in saphenous vein grafts (SVG).

BACKGROUND

Patients with diabetes mellitus have less favorable acute and long-term outcomes after stent implantation in native coronary arteries. The impact of diabetes on SVG stenting, however, is not known.

METHODS

We studied 908 consecutive patients (1,366 SVG lesions) treated with Palmaz-Schatz stents. In-hospital and late clinical outcomes (death, Q-wave myocardial infarction and repeat revascularization rates at one year) were compared between diabetic (n = 290) and nondiabetic (n = 618) patients.

RESULTS

In-hospital mortality was significantly higher in diabetic as compared with nondiabetic patients (2.2% vs. 0.3%, p = 0.003). At one-year follow-up, target lesion revascularization (TLR) was 16.6% in diabetic and 12.3% in nondiabetic patients (p = 0.03). Overall cardiac event-free survival (freedom from death, Q-wave myocardial infarction and any coronary revascularization procedure) at one year was significantly lower in the diabetic (68%) compared with the nondiabetic patients (79%, p = 0.0003). By Cox regression analysis, diabetes mellitus was an independent predictor of both TLR (relative risk: 1.23; confidence interval: 0.96 to 1.58; p = 0.004) and late cardiac events (relative risk: 1.40; confidence interval: 1.05 to 1.86; p = 0.02).

CONCLUSIONS

Patients with diabetes undergoing stent implantation in SVG have: 1) higher in-hospital and late mortality, 2) higher one-year TLR rates, and 3) significantly lower one-year cardiac event-free survival. Thus, diabetic patients have less favorable acute and late clinical outcomes after stent implantation in SVG lesions.

Prognostic value of recurrent episodes of creatine kinase-MB elevation following repeated catheter-based coronary interventions

Creatine kinase-MB (CK-MB) enzyme elevations were shown to affect cardiac prognosis following percutaneous coronary interventions (PCIs). This study examined whether recurrent episodes of CK-MB elevation following repeated PCIs may be associated with a cumulative adverse prognostic risk. We studied 767 consecutive patients (age, 64 +/- 11 years; 69% male) who underwent two consecutive PCI procedures on two separate hospitalizations (mean interval, 121 +/- 110 days). Patients were stratified into four groups according to number of episodes of any (> 4 ng/ml) postinterventional CK-MB rise (no elevation, previously elevated, currently elevated, or elevated at the time of both procedures; n = 403, 107, 153, and 104 patients, respectively). In-hospital clinical outcomes (death, Q-MI, and repeat revascularization) and up to 1-year follow-up events were obtained. Recurrent episodes of CK-MB elevation were associated with increased in-hospital mortality (3.8% vs. 0.9% vs. 0% vs. 0%, P = 0.0003), increased cumulative mortality (18.9% vs. 5.9% vs. 4.3% vs. 4.3%, P = 0.0003) and cumulative Q wave MI (8.0% vs. 4.9% vs. 1.0% vs. 0.8%, P = 0.005) at 1 year, and lower overall cardiac event-free survival at follow-up (66.8% vs. 80.5% vs. 88.8% vs. 88.8%, P = 0.0001 for patients with twice, current, previous, and no CK-MB elevation, respectively). By multivariate analysis, CK-MB elevated at the time of both procedures, was the strongest independent predictor for cumulative mortality (OR 3.4, 95% CI 1.6-7.1, P = 0.001) or any adverse cardiac events (OR 2.6, 95% CI 1.6-4.3, P = 0.0002). We conclude that cumulative episodes of periprocedural CK-MB elevation are associated with an incremental adverse prognostic risk including mortality and Q-wave MI. Thus, measures aimed at reducing subsequent CK-MB rise may be warranted in particular among patients with a prior history of PCI related CK-MB elevation.

Short- and intermediate-term clinical outcomes from direct myocardial laser revascularization guided by biosense left ventricular electromechanical mapping

BACKGROUND

Direct myocardial revascularization (DMR) has been examined as an alternative treatment for patients with chronic refractory myocardial ischemic syndromes who are not candidates for conventional coronary revascularization. Methods and Results-We used left ventricular electromagnetic guidance in 77 patients with chronic refractory angina (56 men, mean age 61+/-11 years, ejection fraction 0.48+/-0.11) to perform percutaneous DMR with an Ho:YAG laser at 2 J/pulse. Procedural success (laser channels placed in prespecified target zones) was achieved in 76 of 77 patients with an average of 26+/-10 channels (range 11 to 50 channels). The rate of major in-hospital cardiac adverse events was 2.6%, with no deaths or emergency operations, 1 patient with postprocedural pericardiocentesis, and 1 patient with minor embolic stroke. The rate of out-of-hospital adverse cardiac events (up to 6 months) was 2.6%, with 1 patient with myocardial infarction and 1 patient with stroke. Exercise duration after DMR increased from 387+/-179 to 454+/-166 seconds at 1 month and to 479+/-161 seconds at 6 months (P=0.0001). The time to onset of angina increased from 293+/-167 to 377+/-176 seconds at 1 month and to 414+/-169 seconds at 6 months (P=0.0001). Importantly, the time to ST-segment depression (>/=1 mm) also increased from 327+/-178 to 400+/-172 seconds at 1 month and to 436+/-175 seconds at 6 months (P=0.001). Angina (Canadian Cardiovascular Society classification) improved from 3.3+/-0.5 to 2.0+/-1.2 at 6 months (P<0.001). Nuclear perfusion imaging studies with a dual-isotope technique, however, showed no significant improvements at 1 or 6 months.

CONCLUSIONS

Percutaneous DMR guided by left ventricular mapping is feasible and safe and reveals improved angina and prolonged exercise duration for up to a 6-month follow-up.

Effects of cilostazol on angiographic restenosis after coronary stent placement

This study evaluates the impact of cilostazol on post-stenting restenosis. Cilostazol is a potent antiplatelet agent with antiproliferative properties. Few data are available about the effect of cilostazol on poststenting restenosis. Four hundred nine patients (494 lesions) who were scheduled for elective stenting were randomized to receive aspirin plus ticlopidine (group I, n = 201, 240 lesions) or aspirin plus cilostazol (group II, n = 208, 254 lesions), starting 2 days before stenting. Ticlopidine was given for 1 month and cilostazol for 6 months. Follow-up angiography was performed at 6 months, and clinical evaluation at regular intervals. Baseline characteristics were similar between the 2 groups. The procedural success rate was 99.6% in group I and 100% in group II. There were no cases of stent thrombosis after stenting. Angiographic follow-up was performed in 380 of the 494 eligible lesions and the angiographic restenosis rate was 27% in group I and 22.9% in group II (p = NS). However, diffuse type in-stent restenosis was more common in group I than in group II (54.2% vs 26.8%, respectively, p <0.05). In diabetic patients, the angiographic restenosis rate was 50% in group I and 21.7% in group II (p <0.05). Clinical events during follow-up did not differ between the 2 groups. In conclusion, aspirin plus cilostazol seems to be an effective antithrombotic regimen with comparable results to aspirin plus ticlopidine, but it does not reduce the overall angiographic restenosis rate after elective coronary stenting.

Long-term outcomes of minor plaque prolapsed within stents documented with intravascular ultrasound

The direct relationship between minor plaque prolapsed within stents and late in-stent restenosis is unknown. Therefore, we evaluated the impact of minor plaque prolapse on late angiographic in-stent restenosis. Intravascular ultrasonography (IVUS)-guided single-coronary stenting was successfully performed on 384 consecutive patients with 407 native coronary lesions. Six-month follow-up angiographic evaluation was performed on 315 patients (82. 0%) with 334 lesions (82.1%). Minor plaque prolapsed within the stent was found in 75 of 334 lesions (22.5%). Results were evaluated using angiographic and IVUS methods. The development of minor plaque prolapse was significantly associated with infarct-related artery (P = 0.000) and small pre-intervention minimal lumen diameter (P = 0. 001). The overall angiographic restenosis rate was 23.1% (77/334)-21.3% (16/75) in the lesions with plaque prolapse vs. 23.6% (61/259) in the lesions without plaque prolapse (P = 0.806). In conclusion, minor plaque prolapsed within stents might not be associated with late angiographic in-stent restenosis.

Intravascular ultrasound findings of negative arterial remodeling at sites of focal coronary spasm in patients with vasospastic angina

BACKGROUND

There are few data about the intravascular ultrasound (IVUS) findings in patients with vasospastic angina, especially regarding patterns of vascular remodeling.

METHODS AND RESULTS

Coronary spasm was documented by angiography and electrocardiographic evidence of ischemia in 36 patients after administration of ergonovine (cumulative doses up to 350 microg). After relief of spasm with 1000 microg of intracoronary nitroglycerin, quantitative angiography and IVUS imaging were performed and analyzed by standard methods. The 36 focal spasm sites were compared with the proximal and distal reference segments. The angiographic baseline minimum lumen diameter measured 1.78 +/- 0.66 mm, which decreased to 0.66 +/- 0.38 mm with ergonovine provocation (P <.0001), increased to 2.66 +/- 0.64 mm after intracoronary nitroglycerin (P <.0001 compared with baseline and after ergonovine), and did not change after IVUS imaging (2.66 +/- 0.63, P =.9). By IVUS, atherosclerotic lesions were observed at all coronary spasm sites; the mean plaque burden measured 56% at the spasm site and 35% at the reference. Spasm site plaque composition was hypoechoic in 31 and hyperechoic, noncalcific in 5; there was no calcium. The mean eccentricity index (maximum divided by minimum plaque thickness) was 6.7. Positive remodeling (spasm site arterial area greater than proximal reference) was present in 5; intermediate remodeling (proximal reference greater than spasm site greater than distal reference arterial area) was present in 7; and negative remodeling (spasm site arterial area less than distal reference) was present in 24.

CONCLUSIONS

Sites of vasospasm in patients with variant angina showed characteristics of early atherosclerosis, except for an unusually high incidence of negative arterial remodeling.

Side-branch occlusion after rotational atherectomy of in-stent restenosis: incidence, predictors, and clinical significance

We evaluated the incidence, predictors, and clinical significance of side-branch occlusion (SBO) after rotational atherectomy (RA) for treatment of in-stent restenosis (ISR) and compared it with those of native coronary artery (NC). RA was performed in 64 patients with 34 ISR (42 side branches) and 30 NC (40 side branches). SBO occurred 14% after RA in ISR group compared with 0% in NC group (P < 0.05), and 33% after adjunctive balloon inflation in ISR group compared with 2.5% in NC group (P < 0.01). Non-Q myocardial infarction developed in seven patients in ISR group and four patients in NC group (P = NS). The presence of significant side-branch (SB) ostial disease (OR = 4.7, P < 0.05) and ISR lesions (OR = 15.5, P < 0.05) were the only independent predictors of SBO by multivariate analysis. The incidence of SBO is higher after RA of ISR than RA of NC and may be associated with an increased risk of non-Q myocardial infarction.

Safety and clinical impact of ergonovine stress echocardiography for diagnosis of coronary vasospasm

OBJECTIVES

We sought to address the issues of safety, feasibility and clinical impact of noninvasive diagnosis of coronary vasospasm (CVS).

BACKGROUND

The safety of ergonovine provocation for CVS performed outside the catheterization laboratory has been questioned.

METHODS

We performed a retrospective analysis of the results of bedside ergonovine provocation testing by monitoring left ventricular regional wall motion abnormalities (RWMAs) using two-dimensional echocardiography (Erg Echo).

RESULTS

After confirming that there was no significant epicardial coronary stenosis, Erg Echo was performed on 1,372 patients from July 1991 to December 1997. Ergonovine echocardiography was terminated prematurely in 13 patients (0.9%) because of limitations caused by side effects unrelated to myocardial ischemia. Among 1,359 completed tests, 31% (n = 421) showed positive results, with development of RWMAs in 412 tests (98%) or ST displacement in electrocardiograms of nine tests (2%). Arrhythmias developed in 1.9% (26/1,372), including transient ventricular tachycardia (n = 2) and atrioventricular block (n = 4), which were promptly reversed with nitroglycerin. There was no mortality or development of myocardial infarction. Based on the angiographic criteria of 218 patients, the sensitivity and specificity of Erg Echo for the diagnosis of CVS were 93% and 91%, respectively. Since 1994, Erg Echo has become a more popular diagnostic method than invasive spasm provocation testing in the catheterization laboratory and has comprised more than 95% of all spasm provocation tests during the last three years. In the outpatient clinic, 453 patients underwent Erg Echo safely.

CONCLUSIONS

Although this is a retrospective study in a single center, we believe that Erg Echo is highly feasible, accurate and safe for the diagnosis of CVS and can replace invasive angiographic spasm provocation testing in the catheterization laboratory.

Histopathologic analysis of in-stent neointimal regression in a porcine coronary model

BACKGROUND

Animal and clinical studies have demonstrated late regression of in-stent neointima. This study was performed to identify the temporal changes in the in-stent neointimal constituents responsible for late regression.

METHODS

NIR stents were implanted in porcine coronary arteries (size of stent (in mm) to size of artery (in mm) approximately equal to 1.1) and harvested at 2 months and 6 months (n = 6 stents/group). Histopathologic analyses included morphometric analysis, smooth muscle cell density, and extracellular matrix contents.

RESULTS

Compared with the findings at 2 months, at 6 months there was a significant reduction in area stenosed (from 21 +/- 3% to 14 +/- 1%, P < 0.05) and neointimal thickness (from 0.2 +/- 0.03 mm to 0.03 +/- 0.02 mm, P < 0.05), despite similar injury scores (0.05 +/- 0.06 at 2 months and 0.36 +/- 0.29 at 6 months). This regression was accompanied mainly by a reduction in proteoglycan (from 24 +/- 19% to 5 +/- 8%, P = 0.05), with no change in smooth muscle cell density (71 +/- 7 compared with 76 +/- 23/high power field) or collagen content (25 +/- 19% compared with 25 +/- 19%).

CONCLUSIONS

The study confirmed the regression of in-stent neointima, which was mainly attributable to a reduction in proteoglycan content, resembling the natural healing response.

Comparison of debulking followed by stenting versus stenting alone for saphenous vein graft aortoostial lesions: immediate and one-year clinical outcomes

OBJECTIVES

We compared in-hospital and one-year clinical outcomes in patients undergoing debulking followed by stent implantation versus stenting alone for saphenous vein graft (SVG) aortoostial lesions.

BACKGROUND

Stent implantation in SVG aortoostial lesions may improve procedural and late clinical outcomes. However, the impact of debulking before stenting in this complex lesion subset is unknown.

METHODS

We studied 320 consecutive patients (340 SVG aortoostial lesions) treated with Palmaz-Schatz stents. Debulking with excimer laser or atherectomy was performed in 133 patients (139 lesions) before stenting (group I), while 187 patients (201 lesions) underwent stent implantation without debulking (group II). Procedural success and late clinical outcomes were compared between the groups.

RESULTS

Overall procedural success (97.6%) was similar between the groups. Procedural complications were also similar (2.2% for group I and 2.6% for group II). At one-year follow-up, target lesion revascularization (TLR) was 19.4% for group I and 18.2% for group II (p = 0.47). There was no difference in cumulative death or Q wave myocardial infarction between the groups. Overall cardiac event-free survival was similar (69% for group I and 68% for group II). By Cox regression analysis, the independent predictors of late cardiac events were final lumen cross-sectional area (CSA) by intravascular ultrasound (IVUS) (p = 0.001) and restenotic lesions (p = 0.01). Similarly, final IVUS lumen CSA (p = 0.0001) and restenotic lesions (p = 0.006) were found to predict TLR at one year.

CONCLUSIONS

These results suggest that, in most patients with SVG aortoostial lesions, debulking before stent implantation may not be necessary.

Long-term clinical events following creatine kinase--myocardial band isoenzyme elevation after successful coronary stenting

OBJECTIVE

We sought to evaluate the impact of intermediate creatine kinase-myocardial band isoenzyme (CK-MB) elevation on late clinical outcomes in patients undergoing successful stent implantation in native coronary arteries.

BACKGROUND

Elevations of CK-MB after percutaneous coronary interventions are frequent. An association between high level of CK-MB elevation (>5 times normal) and late mortality after balloon and new device angioplasty has been reported previously. However, significant controversy remains on the long-term clinical importance of lower CK-MB elevations (one to five times normal) after percutaneous coronary revascularization. Moreover, the incidence and prognostic importance of cardiac enzyme elevation after coronary stenting have not been well established.

METHODS

Prospectively collected data from 900 consecutive patients (1,213 lesions) undergoing successful stenting in native vessels were analyzed. Based on the CK-MB levels after coronary stenting, patients were classified into three groups: normal group 1 (n = 585), elevation of >1 to 5 times normal group 2 (n = 238) and elevation of >5 times normal group 3 (n = 77).

RESULTS

Patients in group 3 had more in-hospital recurrent ischemia (p = 0.001) and pulmonary edema (p = 0.01) than patients in groups 1 and 2. Long-term clinical end points were similar between groups 1 and 2. However, patients in group 3 had an increased incidence of late mortality compared with patients in groups 2 and 1 (6.9%, 1.2% and 1.7%, respectively, p = 0.01). Multivariate analysis showed that patients with CK-MB >5 times normal after coronary stenting had an increased risk of major adverse clinical events (relative risk: 1.70, p < 0.05) and death (relative risk: 3.25, p < 0.05) that was not observed in patients with lower CK-MB rise.

CONCLUSIONS

Patients with CK-MB elevation >5 times normal had higher late mortality and more unfavorable event-free survival than those patients with normal or lower CK-MB rise after coronary stenting. While intermediate CK-MB elevation (>1 to 5 times normal) is frequent after coronary stenting (26%), this was not associated with an increased risk of late mortality or major adverse clinical events.

Multivessel coronary stenting versus bypass surgery in patients with multivessel coronary artery disease and normal left ventricular function: immediate and 2-year long-term follow-up

BACKGROUND

Compared with coronary artery bypass surgery (CABG), the clinical benefits of intracoronary stenting have not been established in patients with multivessel coronary lesions.

METHODS AND RESULTS

To compare the clinical outcomes of intracoronary stenting with that of CABG, we reviewed the outcomes of patients with multivessel coronary artery disease from an observational database. Two hundred consecutive patients with multivessel coronary artery disease and normal left ventricular function were evaluated. In 200 patients, multivessel stenting was performed in 100 and CABG was performed in 100. Complete revascularization was achieved in 95% in the CABG group and in 69% in the stent group (P <.05). The duration of total hospital stay and coronary care unit admission was significantly shorter in the stent group (P <.05). The long-term survival was similar between the 2 groups. There were no significant differences of cardiac events between the 2 groups except for the recurrence of angina (19% in stenting vs 8% in CABG, P =.03) and target lesion revascularization (19% vs 2%, P <.01) in the patients with stents.

CONCLUSIONS

In selected patients with multivessel coronary artery disease and normal left ventricular function, intracoronary stenting may offer an effective alternative to coronary bypass surgery.

Pressure-derived fractional collateral blood flow: a primary determinant of left ventricular recovery after reperfused acute myocardial infarction

OBJECTIVES

We evaluated the relation between pressure-derived fractional collateral flow (PDCF) and left ventricular (LV) recovery after reperfused acute myocardial infarction (AMI).

BACKGROUND

The functional significance of collateral flow remains uncertain in AMI.

METHODS

The PDCF was measured in 70 patients with first AMI (pain onset <12 h) treated with primary angioplasty (PA), being determined by simultaneous measurement of mean aorta pressure (Pa), distal coronary pressure during the balloon occlusion (Poc), and central venous pressure (CVP): (Poc - CVP)/(Pa - CVP)*100. Sufficient collateral (group I) was defined as PDCF index >24% and insufficient collateral (group II) as PDCF index <24%. Echocardiography was performed before, and on day 3, day 7, and day 30 after PA. Wall-motion recovery index (RI) was obtained by dividing the number of improved wall-motion segments (>grade 1) at follow-up by the number of abnormal wall-motion segments within the infarct zone at baseline.

RESULTS

Baseline characteristics were similar between both groups. Peak levels of creatine kinase were lower in group I than in group II (2,600+/-1,900 U/liter vs. 4,100+/-3,000, p < 0.05). At one month, infarct zone wall-motion score index (1.65+/-0.54 vs. 2.31+/-0.46, p < 0.01) and LV volume indexes were smaller in group I than in group II, whereas, LV ejection fraction was higher in group I than in group II (52.8+/-8.3 vs. 45.9+/-9.0, p < 0.01). The PDCF index was the strongest predictor of RI at one month (r = 0.61, p < 0.01). Time to reperfusion was not related to RI at one month. However, it was significantly related to RI in group II (r = -0.34, p < 0.05).

CONCLUSIONS

The LV recovery after reperfused AMI is primarily determined by PDCF and is less dependent on time to reperfusion in patients with sufficient collaterals.