Sirolimus, Tacrolimus and Zotarolimus eluting stents to treat bifurcated lesions: a 7-month clinical outcome comparison

AIM

Drug eluting stents (DES) have been shown to reduce restenosis compared with bare metal stents in bifurcated lesions. The aim of this study was to evaluate the long-term clinical outcomes of patients with bifurcated lesions treated by 3 different DES.

METHODS

Consecutive patients with symptomatic coronary artery disease on one bifurcated lesion with SB>2.25 mm (on visual estimation) undergoing at the Department of Cardiology of the Catholic University of Rome, Italy were screened. Patients treated with Sirolimus-eluting stent (Cypher Select; SES Group), Tacrolimus-eluting stent (Taxus-Libertè; TA Group) and Zotarolimus-eluting stent (Endeavor Driver; ZOT Group) were enrolled in the study. Clinical and angiographic characteristics of all patients were prospectively recorded. Major adverse clinical events (MACE), including death, acute myocardial infarction (MI) or target lesion revascularization (TVR) by either percutaneous coronary intervention (PCI) or coronary surgery were recorded during the follow-up. Incidence of definite or probable stent thrombosis was calculated according to the ARC criteria.

RESULTS

Two hundred and forty-one consecutive patients were enrolled (89 Group CY, 98 Group TA and 54 Group EN). Length of follow-up was 235+/-60 days. Baseline clinical and angiographic characteristic were similar across the groups. The adopted technique for stent implantation was provisional stenting (73.4%), T-stenting technique (7%), crush (7%) and V-stenting (2.6%). The rate of patients finally treated with two stents was similar among groups. The cumulative rate of MACE (9% SES, 12% TA, 11% ZOT: P=0.7) and of TVR (2% SES, 9% TA, 7% ZOT) was similar among groups. No definite stent thrombosis was observed during follow-up, while 1 probable stent thrombosis was observed in TA group.

CONCLUSION

The clinical outcome of bifurcated lesions using DES and mainly a technique of single stent implantation is good. In the present observational study, clinical adverse events did not differ in patients with bifurcated lesions treated by Cypher, Taxus or Endeavor stent implantation.

Increased mortality after coronary stenting in patients treated with clopidogrel without loading dose. Evidence from a meta-analysis

AIM

Clopidogrel is an established alternative to ticlopidine in addition to aspirin after coronary stenting because of its hematologic safety, but its efficacy in comparison to ticlopidine is debated. We thus systematically reviewed randomized trials comparing clopidogrel vs ticlopidine after coronary stenting.

METHODS

Medline (1/1986-10/2003), BioMed Central, Central, Current Contents, LILACS and mRCT were searched. Fixed-effect relative risks (RR [95% CI]) were computed, and the primary end-point was death. Heterogeneity tests and subgroup analyses were performed according to loading vs non-loading clopidogrel scheme.

RESULTS

Five trials were retrieved (2 962 patients, average follow-up 7.4 months). In 3 studies both clopidogrel and ticlopidine were started with a loading dose, in 1 trial clopidogrel was administered without loading, and in 1 trial clopidogrel could be administered with or without loading. Overall analysis (p for heterogeneity=0.12) showed a non-significant trend toward increased mortality in patients treated with clopidogrel (38/1 649 [2.3%]) vs ticlopidine (22/1 313 [1.7%], RR=1.64 [0.94-2.86], p=0.080). After stratification, clopidogrel with loading was associated with non-significantly lower mortality rates than ticlopidine (9/959 [0.9%] vs 13/798 [1.6%], RR=0.68 [0.29-1.63], p=0.39). Instead, clopidogrel without any loading yielded a highly significantly 3-fold increased risk of death than ticlopidine (29/690 [4.2%] vs 9/515 [1.7%], RR=2.9 [1.45-6.1], p=0.0029). Similar results were obtained for the rate of death or non-fatal myocardial infarction.

CONCLUSION

This meta-analysis suggests that clopidogrel treatment including a loading regimen is equivalent or may even be superior to ticlopidine after coronary stenting. However, current evidence shows conversely that clopidogrel therapy in the absence of a loading dose is associated with a significantly higher risk of death or myocardial infarction.

Major racial differences in coronary constrictor response between japanese and caucasians with recent myocardial infarction

BACKGROUND

Enhanced coronary vasomotion may contribute to acute coronary occlusion during the acute phase of myocardial infarction (AMI). Japanese have a higher incidence of variant angina than Caucasian patients, but racial differences in vasomotor reactivity early after AMI are controversial.

METHODS AND RESULTS

The same team studied 15 Japanese and 19 Caucasian patients within 14 days of AMI by acetylcholine injection into non-infarct-related (NIRA) and infarct-related (IRA) coronary arteries followed by nitroglycerin. Incidence of vasodilation, vasoconstriction, spasm, and basal tone were assessed in proximal, middle, and distal segments after each drug bolus by quantitative angiography. Japanese patients had much lower cholesterol levels than Caucasians (183+/-59 versus 247+/-53 mg/dL, P<0.006) but showed a lower incidence of vasodilation (2% versus 9% of coronary segments) and a greater incidence of spasm after acetylcholine (47% versus 15% of arteries, P<0.00001). Incidence of spasm was higher in IRAs than in NIRAs in both populations (67% versus 39% and 23% versus 11%, respectively). Multivessel spasm was more common (64% versus 17%, P<0.02) and vasoconstriction of nonspastic segments was greater in Japanese patients (-23.4+/-14.9% versus -20.1+/-15.7%, P<0.02) in the presence of similar average basal coronary tone with respect to post-nitroglycerin dilation and of nonsignificant differences of coronary atherosclerotic score.

CONCLUSIONS

Soon after AMI, Japanese patients exhibited a 3-fold-greater incidence of spasm and greater vasoconstriction of nonspastic segments after acetylcholine than Caucasians. The causes of such differences warrant further investigation because they may have relevant pathophysiological and therapeutic implications.

Circadianicity of hemostatic function and coronary vasomotion

Acute myocardial infarction, sudden cardiac death and ischemic stroke show a circadian periodicity, occurring more frequently in the morning. Because arterial thrombosis is common to these disorders, a circadianicity of prothrombotic and antithrombotic processes may contribute to explain the 24 h rhythms of these acute events. Available data indeed indicate that coronary vasomotor tone, platelet aggregability, plasma inhibition of fibrinolysis, coagulant activity and blood viscosity are all greater in the morning than at other times of day, producting a relative prothrombotic state in the early morning.

Low incidence of serotonin-induced occlusive coronary artery spasm in patients with recent myocardial infarction

Intracoronary infusion of serotonin has been reported to induce varying degrees of coronary vasoconstriction in different coronary syndromes, but it has never been studied in patients after myocardial infarction. In patients with recent myocardial infarction, we found a low incidence (11%) of serotonin-induced occlusive spasm only in the infarct-related artery (IRA), and a significantly higher vasoconstriction in the distal segment of the IRA than in the same segment of the non-IRA.

Color Doppler study of mitral regurgitation during percutaneous transluminal coronary angioplasty

Mitral regurgitation (MR) was evaluated by color Doppler echocardiography during percutaneous transluminal coronary angioplasty (PTCA) in 28 patients with one-vessel artery disease (left anterior descending artery in 11, right coronary artery in 8, and circumflex artery in 9) and normal left ventricular function. In all three groups, left ventricular ejection fraction (LVEF) and wall motion score index (WMSI) decreased significantly during artery occlusion in comparison with baseline values (no differences among various groups). Anterior and inferior akinesia/dyskinesia was observed in all patients during left anterior descending and right coronary artery occlusion, respectively. Lateral akinesia/dyskinesia was induced by occlusion of the circumflex artery in six patients (all with proximal lesions [p < 0.05 vs the other two groups]) and the right coronary artery in one. Only the six patients with circumflex artery occlusion showed PTCA-related MR (> 2+ in two). LVEF and WMSI were similar during artery occlusion in patients with and without MR. Neither mitral leaflet prolapse nor anulus dilation occurred during PTCA in any of the patients. Our data show that during brief occlusion of the proximal circumflex artery, functional MR (usually mild) frequently occurs in relation to specific lateral akinesia/dyskinesia.

Abnormal intraventricular flow patterns in left ventricular dysfunction determined by color Doppler study

We examined the relation between left ventricular (LV) flow dynamics measured by color Doppler, and either global or regional LV function in 19 normal subjects (group 1), in 55 patients with old myocardial infarction (MI) (29 without [group 2] and 26 with LV aneurysm [group 3]), and in 16 with idiopathic dilated cardiomyopathy (group 4). We calculated by M-mode color Doppler a flow persistence index (FPI) (duration of flow directed in systole toward the apex/LV ejection time). Contrast echocardiography was performed as a control method in 14 patients of the four groups. In normal subjects, rapid systolic inversion of flow toward the aorta was evident (FPI: 0.11 +/- 0.16). In all but one patient in group 2, a similar LV flow pattern was observed, but FPI was greater (0.32 +/- 0.26). In groups 3 and 4, a paradoxical antegrade LV flow pattern was evident during the entire period of systole (FPI: 1.13 +/- 0.42 and 1.28 +/- 0.36, respectively). LV flow patterns were reproduced in echo-contrast studies. FPI was related to LV end-diastolic volume (r = 0.77), end-systolic volume (r = 0.82), and ejection fraction (r = -0.84). However, when data were analyzed separately in the different groups, these correlations were significant only in groups 2 and 3. Paradoxical flow pattern is not peculiar to regional LV dysfunction; it also occurs in global LV dysfunction. This LV flow abnormality may develop after MI even in the absence of severe LV dyssynergy or dilation, and is quantitatively related to the degree of LV dysfunction.

Anomalous coronary arteries: a report of 2 cases of single coronary artery

One patient with chronic exertional angina, not significant electrocardiographic signs of myocardial ischemia at exercise stress test and recent onset of angina at rest underwent coronary arteriography. A second one with known severe aortic stenosis underwent cardiac catheterization and coronary arteriography because of effort chest pain and syncope. A single coronary artery originating respectively from the right and from the left sinus of Valsalva but without significant coronary stenosis was detected in both patients. This entity is a quite uncommon finding of relevant interest if surgical treatment is required and good prognosis if not associated with additional cardiac anomalies.

Ventricular arrhythmia induced by programmed ventricular stimulation after acute myocardial infarction

The prevalence, characteristics and clinical significance of ventricular electrical instability with programmed ventricular stimulation was studied in 50 hemodynamically stable patients 17 to 40 days after acute myocardial infarction (AMI) using double extrastimuli at 2- and 10-mA intensity and from 2 right ventricular sites. Ventricular electrical instability was defined as induction of 10 or more consecutive intraventricular reentrant beats. Of 50 patients, 23 (46%) had ventricular electrical instability (10 of these had sustained ventricular tachycardia [VT] induced). No significant differences were observed between patients with and without ventricular electrical instability with respect to age, site of AMI, coronary prognostic index, maximal level of CK, number of narrowed coronary arteries and presence of severe wall motion abnormalities. During a mean follow-up of 11.2 months no patient died suddenly. During repeated Holter recordings patients with ventricular electrical instability had a higher incidence of nonsustained VT than did patients without ventricular electrical instability.

Assessment of tricuspid regurgitation by pulsed Doppler ultrasonography of the hepatic veins

Pulsed Doppler echocardiography was tested to assess the degree of tricuspid regurgitation (TR), classified by right ventriculography, in 47 patients. Forty-eight subjects without TR served as controls (39 with sinus rhythm and 9 with atrial fibrillation). Two Doppler methods were used: the distance of systolic turbulence within right atrium from the tricuspid plane and the quantitative analysis of the flow-velocity traces from the hepatic veins (HVs). Right atrial systolic turbulence was found in 41 of 47 patients with TR and in none of the control subjects, and moderately correlated with the angiographic grading (r = 0.57). In control subjects, TR flow-velocity traces from the HVs showed 2 anterograde flow waves, systolic and diastolic. The ratio of anterograde systolic/anterograde diastolic velocity was more than 0.6 in 38 subjects with sinus rhythm and in 8 with atrial fibrillation. Twenty-two control subjects had a positive wave (designated as "v") coincident with the end of T wave. In 30 patients with TR, a retrograde holosystolic wave was present. Of the remaining patients, 12 had a ratio of anterograde systolic/anterograde diastolic velocity less than 0.6. Fifteen had an end-systolic "v-like" wave, which occurred earlier than the v wave in control subjects (p less than 0.001). In patients with TR, maximal velocities of the anterograde diastolic and retrograde systolic flow correlated with angiographic grading (r = 0.74 and 0.73, respectively). An anterograde diastolic flow velocity more than 26 cm/s and a retrograde systolic flow velocity more than 16 cm/s excluded mild TR. Analysis of Doppler recordings of the HVs is valuable to semiquantitatively assess TR, complementing the right atrial Doppler findings.

Assessment of left atrial dimensions by cross sectional echocardiography in patients with mitral valve disease

Left atrial dimensions were measured using cross sectional echocardiography in 37 patients with mitral valve disease and 30 normal subjects of similar ages. The anteroposterior (AP), superior-inferior (SI), and medial-lateral (ML) left atrial dimensions were determined at the end of ventricular systole using parasternal long and short axis and apical four chamber views (for SIa and MLa). To assess the reliability of these measurements cross sectional echocardiographic and angiographic left atrial volumes were compared in 19 patients with mitral valve disease, giving an excellent correlation. A moderate correlation was found between the anteroposterior dimension of the left atrium obtained using M mode echocardiography and that obtained using the parasternal short axis and long axis projections. In normal subjects a good correlation was found between SI and ML dimensions, while a lower correlation was found between SI and AP, and ML and AP dimensions. The SI dimension was the major axis of the left atrium and AP dimension the minor axis. In patients with mitral valve disease a good correlation was found between SI and ML dimensions, while SI and ML dimensions had a low correlation with AP dimensions. The AP dimension was the minor axis of the left atrium, while the SI and ML dimensions were not significantly different. All left atrial dimensions were significantly greater in patients with mitral valve disease than in normal subjects. Of 30 patients with at least one dimension increased, all three dimensions were abnormal in 16, two dimensions were increased in 10, and only one dimension was increased in four. AP, SI, and ML dimensions were abnormal in 25, 20, and 27 patients, respectively. Cross sectional echocardiography may provide a reliable estimate of left atrial dimensions. In patients with mitral valve disease a thorough examination of the left atrium using multiple cross sectional views is necessary to detect asymmetric left atrial enlargement and to measure the degree of left atrial dilatation.

Significance of high voltage QRS anterior forces in young asymptomatic adults. Evaluation by wide-angle two-dimensional echocardiography

Thirteen asymptomatic adults less than 40 years old who showed tall right precordial R waves on the ECG were examined by VCG, M-mode and two-dimensional echocardiography (2D Echo). Common causes of QRS anterior displacement, such as right ventricular enlargement or right bundle branch block, were excluded in each subject. Although each subject was normal at physical examination, 2D Echo revealed areas of left ventricular hypertrophy in eight of these 13 subjects. Four had a prevailing hypertrophy of the basal portion of the interventricular septum, three had an isolated apical hypertrophy, and one had a diffuse concentric left ventricular hypertrophy. Results were normal in five cases. 2D Echo classification was confirmed by heart catheterization findings, when available. The subjects with asymmetric septal hypertrophy showed low-voltage QRS leftward forces on the ECG and VCG. ECGs and VCGs were not useful in differentiating the subjects with atypically distributed left ventricular hypertrophy from the normals: high-voltage QRS leftward forces and T wave abnormalities were evident in some subjects of both groups. Tall right precordial R waves may constitute a marker of hypertrophic cardiomyopathy in asymptomatic young adults. 2D Echo is useful to exactly classify these subjects.