Expression of the cardiac ryanodine receptor in the compensated phase of hypertrophy in rat heart.

OBJECTIVES: Abnormal calcium handling is a general feature of cardiac hypertrophy and alteration in the expression of SR proteins has been suggested to be involved in this alteration. To determine the expression of the cardiac ryanodine receptor (Ry2) gene during compensatory hypertrophy, we studied the mRNA and protein accumulation in left ventricles from rats with 30 to 100% hypertrophy. METHODS: Cardiac hypertrophy was obtained after 1 month of aortic constriction. Ry2 mRNA was analyzed by RNase protection assay, Northern and slot blots, and Ry2 protein by high-affinity [3H]ryanodine binding and Western blot. RESULTS: We demonstrate that: (1) the cardiac Ry2 mRNA concentration is decreased by 50% in severe hypertrophy; (2) both the density of the high-affinity sites and the Ry2 protein level are decreased by 25%; (3) the decrease in the mRNA and protein levels and the number of high-affinity sites are highly correlated to the severity of hypertrophy. CONCLUSION: Our results suggest that, as for SR Ca(2+)-ATPase, there is either a downregulation or a lack of upregulation of the gene coding for the Ry2 in compensatory hypertrophy. The decreased density of Ry2 may alter SR Ca2+ transport and contribute to the impaired Ca2+ handling by slowing the Ca2+ movements.

Coronary stenting of bifurcation lesions using "T" or "reverse Y" configuration with Wiktor stent.

The purpose of this study was to determine the immediate and long-term angiographic and clinical results of coronary stenting of bifurcation lesions using the "T" or "reverse Y" configuration with a Wiktor GX stent. This series demonstrates that stents can be placed with a high rate of success in coronary bifurcation lesions and the techniques described will overcome the potential limitations of coronary angioplasty in such lesions.

[Coronary angioplasty in hemodialysis patients]. / Angioplastie coronaire chez l'hémodialysé.

The results of balloon coronary angioplasty are very disappointing in haemodialysis patients because of the high restenosis rate. On the other hand, the use of stents in this population had not previously been assessed. This retrospective study compared 63 coronary patients on haemodialysis with a référence group of 63 paired patients with respect to gender, age, and the necessity or not of stent implantation. There was a higher frequency of hypertension (79 vs 39%) and of hypertriglyceridaema (22 vs 8%) in the haemodialysis group than in the controls. However, there was no significant difference with respect to primary success rate of angioplasty (92 and 89% respectively), nor to the development of early cardiovascular complications (4% and 1.9% respectively). After a two-year follow-up, there was no significant difference in the restenosis rate in the haemodialysis patients (33%) compared with the controls (25%). Nevertheless, the mortality rate at 2 years was higher in the dialysis group (15%) compared with the reference group (3.5%, p = 0.03). However, this mortality rate was lower than that reported in the literature in haemodialysis patients after balloon angioplasty. Therefore, haemodialysis does not increase the risk of restenosis when an optimal angiographic results is obtained either by balloon angioplasty or by angioplasty with stenting. Coronary angioplasty is a safe and effective method of revascularisation in coronary haemodialysis patients when the lesions are accessible to stenting.

[Diagnosis of acute myocardial infarction using multislice computed tomography in emergency room]. / TDM coronaire en urgence dans le diagnostic d'infarctus à la phase aiguë.

Managing chest pain in emergency remains a diagnostic challenge because of the speediness and the accuracy that request. The authors report the case of a 40 years old patient admitted for chest pain with suspected aortic dissection. Multislice computed tomography (sixteen-slice CT) was performed at the patient's admission, initial diagnosis was rapidly corrected, showing both and accurately show both antero-septal defect perfusion and an acute occlusion of the proximal left anterior descending artery. Angioplasty was performed in emergency within the 6 first hours after onset of the symptoms. Multislice computed tomography was able to identify accurately not only the chest pain etiology but also to show the culprit artery, leading to quick and oriented percutaneous coronary intervention.

[Visualization of coronary tree and detection of coronary artery stenosis using 16-slice, sub-millimeter computed tomography: preliminary experience]. / Visualisation des artères coronaires et détection des sténoses significatives au scanner 16 coupes avec synchronisation cardiaque: première expérience.

PURPOSE: multislice CT has been shown as a promising tool for coronary artery imaging. Our goal was to investigate the value of the new sixteen-slice, CT technology for non-invasive visualization of coronary arteries and assessment of coronary stenosis. MATERIALS AND METHODS: we assessed coronary artery visualization in 30 consecutive patients using 16-slice CT and compared the findings with conventional coronary angiography. The whole heart was scanned using 0.75 millimeter slices after injection of contrast medium. Retrospective ECG-gated reconstructions were performed and images were analyzed using axial CT, maximum intensity projection and 3D images, blind to the conventional angiography findings. Seventeen main coronary segments of more than 1.5 mm were analyzed and stenosis was graded on a four-point scale. RESULTS: CT angiography attained diagnostic quality for the whole coronary artery tree in 90% (27/30) of patients. Sixteen of 493 segments (4%) were not interpreted because of substantial motion artifacts (n=12) or heavy calcifications or stenting (n=4). Thirty seven of the 43 cases of significant stenosis (>50%) identified on coronary angiograms were correctly identified with multislice CT. All 6 false negatives involved stenosis of the circumflex artery or branches. Five false positive stenoses were found in 432 non stenotic segments. The sensitivity was thus 86%, specificity 99% for stenosis of more than 50%. CONCLUSION: 16-slice CT provides an excellent visualization of the coronary tree in most patients, allowing accurate non-invasive detection of significant coronary stenosis. Stenoses of the left circumflex artery remain more difficult to detect.

[Anomalies in myocardial contrast uptake revealed by multislice cardiac CT during acute myocarditis]. / Anomalies de la prise de contraste myocardique mises en évidence par le scanner cardiaque multicoupes au cours de myocardites aiguës. A propos de 2 cas.

Acute myocarditis can display many various clinical appearances. Endomyocardial biopsy is an invasive investigation for which the sensibility is insufficient in mild cases and when it is performed too early. Multislice cardiac CT with ECG synchronisation and injection of contrast medium allows visualisation of the coronary arteries and the study of myocardial contrast uptake. We report the cases of two patients with a mild myocarditis where multislice CT performed early showed multiple areas of increased myocardial contrast uptake consistent with a diffuse inflammatory disorder. Coronary angiography was normal in these two patients. Multislice cardiac CT could be a useful non-invasive investigation for the early diagnosis of this disease.

[New thrombolytic agents in myocardial infarction]. / Nouveaux agents thrombolytiques dans l'infarctus du myocarde.

Myocardial infarction is the result of thrombotic coronary artery occlusion. Although present-day thrombolytics have major value by increasing the frequency of reopening of arteries responsible for myocardial infarction, by preserving myocardial function and, thereby, significantly reduce mortality. Nevertheless, they are subject to the following limitations: 1) excellent arterial partency is only obtained in 50% of cases: 2) reocclusion occurs in 5 to 10% of cases; 3) severe complications such as cerebral haemorrhage are observed in about 0.5% of cases. Therefore, the search to improve thrombolytic agents is intense. This article reports the recent advances in concept and production of new thrombolytic agents. The most recent results concern the production of mutants of T-PA (tissue plasmogen activator). Of these mutants, the reteplase (r-PA) has already received authorization for its commercialisation. Other t-PA mutants under development (phase 3) include TNK-t-PA and lanoteplase. Over the last few years, there has been renewed interest in staphylokinase. The results of the initial clinical trials with this agent have also been reported. Paradoxically, the mode of action of thrombolytic agents has an inherent pro-thrombotic effect. This explains some of the interest for anti-thrombotic agents as an adjuvant treatment of thrombolysis. The initial results of the association of thrombolytics with new glycoprotein IIb/IIIa platelet inhibitors and anti-thrombin agents are reported.

[Value of combined coronary angioplasty and coronary angiography]. / Intérêt de l'angioplastie coronaire dans le même temps que la coronarographie.

Combined coronary angioplasty and coronary angiography is performed in most catheter laboratories and has become a routine procedure. The aim of this study was to assess its clinical results and economic value. This was a retrospective monocenter study performed over an 11 year period (1990-2000) which included 2,727 patients requiring coronary angioplasty after coronary angiography. The angioplasty procedure was performed at the same time as angiography (combined, n = 1,809) or after angiography (deferred, n = 631). Patients admitted for acute coronary syndromes not stabilised by pharmacological interventions were excluded from the study. The comparison of these two modes of angioplasty was based on primary success rates, complications, duration of hospital stay and hospital costs. The combined procedure was used progressively more frequently over the study period, increasing from 54% to 88% in 2000. The hospital clinical results (Success and complication rates) were comparable in the two groups. The predictive factors of failure were the year of the angioplasty procedure and occlusive lesions on multivariate analysis. The combined procedure was associated with a shorter hospital stay than deferred angioplasty (8.2 +/- 6.1 days versus 15.0 +/- 8.0 days, p = 0.0001) and with lower costs. The authors conclude that combined coronary angiography-angioplasty is as effective and as safe as deferred angioplasty. It is associated with a shorter hospital stay and lower hospital costs.

[Non-invasive coronarography: myth or reality]. / La coronarographie non invasive: mythe ou réalité.

Slice Imaging technology progress allows a good approach of coronary arteries. MRI and Multislice Computed Tomography (MSCT) are in competition. Inspite of important progress, MRI of coronary artery disease remains "disappointing". With this imaging technology, there is a good plaque burden and myocardium visualisation. MST, and particularly with 16 slice technology, allows a good coronary stenosis identification. This technology enables soft plaque and myocardial ischemia detection. It is now possible to detect coronary heart disease with MSCT, which can replace or help a coronary angiogram in some indications.

Cardiac calcium release channel (ryanodine receptor) in control and cardiomyopathic human hearts: mRNA and protein contents are differentially regulated.

Abnormal intracellular calcium handling in cardiomyopathic human hearts has been associated with an impaired function of the sarcoplasmic reticulum, but previous reports on the gene expression of the ryanodine receptors (Ry2) are contradictory. We measured the mRNA levels, the protein levels and the number of high affinity [3H]ryanodine binding sites in the left ventricle of non-failing (n = 9) and failing human hearts [idiopathic dilated (IDCM n = 16), ischemic (ICM n = 7) or mixed (MCM n = 8) cardiomyopathies]. Ry2 mRNA levels were significantly reduced in IDCM (-30%) and unchanged in MCM and ICM and Ry2 protein levels were similar. In contrast, we observed a two-fold increase in the number of high affinity Ry2 (B(max) = 0.43 +/- 0.11 v 0.22 +/- 0.13 pmol/mg protein, respectively; P<0.01) and an unchanged K(d). Furthermore, levels of myosin heavy chain mRNA and protein per g of tissue were similar in failing and non-failing hearts, suggesting that the observed differences in Ry2 are not caused by the increase in fibrosis in failing heart. Therefore, the dissociation between the two-fold increase in the number of high affinity ryanodine receptors observed in all failing hearts and the slightly decreased mRNA level or unchanged protein level suggests that the ryanodine binding properties are affected in failing myocardium and that such modifications rather than a change in gene expression alter the channel activity and could contribute to abnormalities in intracellular Ca2+ handling.

Clinical outcome following coronary angioplasty in dialysis patients: a case-control study in the era of coronary stenting.

BACKGROUND: Balloon coronary angioplasty has been reported to be ineffective in patients treated for end stage renal disease because of a high restenosis rate. OBJECTIVE: To compare the clinical outcome following coronary angioplasty with provisional stenting in dialysis versus non-dialysis patients. DESIGN: A case-control study. PATIENTS: Of 1428 consecutive patients who underwent coronary angioplasty, 100 (7%) were being treated for end stage renal disease. These were compared with 100 control patients matched for age, sex, coronary lesions, presence of diabetes mellitus, and rate of coronary stenting (40%). MAIN OUTCOME MEASURES: In-hospital and one year clinical outcome. RESULTS: The rates of procedural success (90% v 93%), in-hospital mortality (1% v 0%), stent thrombosis (0% v 0%), and Q wave myocardial infarction (0% v 1%) were similar in dialysis and non-dialysis patients. One year clinical outcome after coronary angioplasty was similar in the two groups in terms of clinical restenosis (31% v 28%) and myocardial infarction (6% v 2%), but cardiac death was more common in dialysed patients (11% v 2%, p < 0.03). CONCLUSIONS: Dialysis does not increase the risk of clinical restenosis after coronary angioplasty with provisional stenting. Coronary angioplasty is a safe and effective therapeutic procedure in selected dialysis patients with culprit lesions accessible to stenting. However, the one year survival is reduced in this high risk population.