Should we still perform angioplasty and stenting of an unprotected left main coronary artery stenosis in heart transplant patients? Two new cases and a review of the literature.

Coronary balloon angioplasty with stent implantation has emerged as a possible alternative to bypass grafting or repeat transplantation in left main coronary stenosis in heart transplant patients. We report 2 new cases of stent implantation for unprotected and isolated left main stenosis in heart transplant patients. Despite an initially successful procedure, restenosis prompted the performance of bypass surgery in both patients. The relative advantages and disadvantages of available techniques of revascularization are discussed in the context of the literature.

[Efficacy and safety of low-dose heparin (30 IU/kg) during coronary angioplasty]. / Efficacité et sécurité d'emploi de faibles doses d'héparine (30 UI/kg) en cours d'angioplastie coronaire.

High doses of heparin are recommended during coronary angioplasty although platelet inhibition seems to play a role in the prevention of ischaemic complications. Low dose heparin could reduce the incidence of local complications without increasing that of major coronary events. The authors report the results of a prospective register of coronary angioplasties performed by the femoral approach with a single bolus of 30 IU/Kg of heparin and immediate withdrawal of the 6 French introducer. Only patients with recent infarction or left main stem disease were excluded. All underwent clinical examination and ultrasonic scanning of the puncture site the day after the procedure. Four hundred and eighteen patients were included (mean age: 63.3 +/- 11 years; 79% men; 77% stenting). The average dose of heparin was 2253 +/- 1056 IU; the average procedure time was 25 +/- 16 minutes, and a final activated clotting time was 174 +/- 69 ms. The duration of normal compression was 7.7 +/- 3 min. Eighty-three point five per cent of patients were discharged the day after the procedure with a global cardiovascular complication rate of 2.87%. At 1 month, 1.67% of secondary cardiovascular events was recorded. Ultrasonography of the puncture site was abnormal in 7.6% of patients. Only one serious vascular complication (0.24%) requiring transfusion and surgical repair, was observed. The authors conclude that the use of low dose heparin appears effective and safe in cases without acute myocardial infarction. This protocol allows faster mobilisation and earlier hospital discharge of patients.

[Dobutamine echocardiography in children after heart transplantation]. / Echocardiographie sous perfusion de dobutamine chez l'enfant après transplantation cardiaque.

Coronary disease of the transplanted heart is the principal cause limiting long-term survival of patients and grafts. In view of the invasive nature of coronary angiography, dobutamine echocardiography has been proposed as a non-invasive diagnostic method for this disease. The aim of this study was to determine the feasibility and reliability of this investigation in transplanted children. Twenty-one echoes were performed with dobutamine infusions in 17 patients transplanted at 10 months to 16.9 years of age (average 8.4 years), and followed up 1.1 to 10.1 years (average 4.4 years): 4 were on antihypertensive drugs but none were treated by betablockers. Dobutamine echocardiography was performed according to the standard protocol used in adults. The maximal level was attained in all cases. No major side effects were observed. The maximal heart rate attained 57 to 89% of the theoretical maximal rate, an increase of 44 to 184% compared with the basal heart rate. The maximal systolic blood pressure rose to 120 to 194 mmHg, an increase of 8 to 109% compared with resting values. The contractility scores and segmental contractile index were normal in 18 cases, abnormal at the maximal level in 2 cases (hypokinesia of segments 8 and 9 and akinesia of segments 10 and 16 with an index of 1.2), abnormal at the lowest levels (hypokinesia of segment 7 with an index of 1.1) and maximal level (hypokinesia of segments 1 and 7 with an index of 1.2) in one case. These results were concordant with coronary angiography performed within 2 to 8 days of echocardiography, and considered as the diagnostic investigation of reference (sensitivity 75%, specificity 100%, positive predictive value 100% and negative predictive value 93%). The authors conclude that dobutamine echocardiography is a non-invasive method easily performed with low risk in transplanted children but its diagnostic performance in coronary disease of the transplanted heart should be confirmed in larger studies.

[Transluminal coronary angioplasty performed in patients with single vessel disease of the right coronary artery disease. Long-term results]. / Angioplasties coronaires transluminales réalisées chez des patients monotronculaires de l'artère coronaire droite. Résultats à long terme.

The patients who have only single vessel disease of the right coronary artery have an excellent prognosis, unaffected by surgery. The object of this study was to evaluate the long-term prognosis of these patients after transluminal coronary angioplasty. The criteria of analysis were survival, anginal symptoms, quality of life and ergometric parameters. Two hundred and forty eight patients with an isolated lesion of the right coronary artery who underwent angioplasty were reassessed 39.6 +/- 22 months after angioplasty. The primary success rate was 89.9% with 5.2% of severe complications during the hospital period (myocardial infarction, bypass surgery, coronary angiography +/- angioplasty). The actuarial global and cardiac survival rates at 7 years were 88.4 and 96.2% respectively with no difference between the success and failure groups. The eight cardiovascular deaths and thirteen myocardial infarctions which were observed in the long-term were all in the successful angioplasty group. From the symptomatic viewpoint, 76% of the population became asymptomatic. The same results were observed in terms of quality of life with 58% of patients estimating it to be good in correlation with anginal status. The comparison of ergometric tests showed a significant gain in performance in 67% of patients. The authors conclude that the results suggest that angioplasty in single vessel disease of the right coronary artery provides a significant symptomatic and ergometric benefit but that it is impossible to assess the eventual benefits in terms of survival which would have needed a group of similar patients assessed under anti-ischaemic treatment and taking into consideration the recent innovations (stents, statins).

[Comparison of iodixanol (Visipaque) and ioxaglate (Hexabrix) in coronary angiography and ventriculography: a double-blind randomized study]. / Comparaison de l'iodixanol (Visipaque) et de l'ioxaglate (Hexabrix) en coronaro-ventriculographie: une étude randomisée en double aveugle.

OBJECTIVE: To evaluate and compare in a double-blinded and prospective study the incidence of adverse reactions between two contrast agents used for coronary angiography and ventriculography. The first agent was the non-ionic, dimeric, isotonic contrast medium iodixanol (Visipaque), the other was the ionic dimeric contrast medium ioxaglate (Hexabrix). METHODS: A total of 110 consecutive patients were randomized and received either iodixanol 320 mgl/ml or ioxaglate 320 mgl/ml. The efficacy, safety, tolerability and specific cardiovascular effects were evaluated. Adverse reactions were recorded during the procedure and during the first 24 hours after the examination. Hemodynamic and electrophysiological parameters were recorded before and after the ventricular injection and the first injections into the left and right coronary artery, respectively. RESULTS: The incidence of clinical adverse reactions was significantly different between iodixanol and ioxaglate (3% vs 28%, p = 0.0004). 24 patients (16 iodixanol; 8 ioxaglate) experienced no discomfort (sensation of warmth, coldness or pain), and the intensity of discomfort experienced by the remainder was similar for the two groups. No patient reported pain. During the 3 minutes after injection of contrast medium, the LV end-diastolic pressure increased but, apart from one reading, the increases with iodixanol were always significantly different (p < 0.05), and less than those for ioxaglate. During the same time period, heart rate was increased to a greater extent by ioxaglate (p < 0.05). QT interval was significantly (p < 0.05) prolonged with both ioxaglate and iodixanol, but the changes were less marked after iodixanol. The angiographic studies were of diagnostic quality for all patients and optimal diagnostic information was achieved in 92% of both groups. CONCLUSION: This randomized study shows that iodixanol and ioxaglate are of comparable diagnostic efficacy in coronary angiography and ventriculography, but that iodixanol is better tolerated by patients and results in less marked hemodynamic and eletrophysiological changes than does ioxaglate.

Troponin I, troponin T, or creatine kinase-MB to detect perioperative myocardial damage after coronary artery bypass surgery.

STUDY OBJECTIVES: To compare cardiac troponin I (cTnI), cardiac troponin T (cTnT), and creatine kinase MB (CKMB mass) in patients with and without new Q wave on the ECG following coronary artery bypass graft (CABG) surgery. PATIENTS: After ethic committee's approval and informed consent, 82 patients, mean age 63+/-10 years, scheduled for CABG were included. INTERVENTIONS: Arterial blood samples were drawn during cardiopulmonary bypass, before, and 6, 12, 24, and 48 h after aortic cross-clamp release. cTnI, cTnT, and CKMB mass were measured. The appearance of new Q wave on the ECG performed preoperatively and 24 h postoperatively was used to assess myocardial lesion independently of biological markers. RESULTS: There were 69 patients without new Q wave on the ECG (group 1) and 13 with (group 2). In group 1, cTnI reached a peak of 2.1 microg/L (median, interquartile range [IQ]=2.4) at 12 h, cTnT increased progressively with a peak of 0.22 microg/L (IQ=0.2) at 48 h, and CKMB presented an earlier peak of 10 microg/L (IQ=6.2) at 6 h. Starting with the same median value, group 2 patients presented significantly higher peaks: cTnI: 17 microg/L (IQ=16) at 12 h; cTnT: 1.4 microg/L (IQ=2.3) at 12 h; and CKMB mass: 74 microg/L (IQ=61) at 6 h. Receiver operating characteristic (ROC) curves were constructed. The area under the curve was 0.90 for cTnI, 0.84 for CKMB, and 0.81 for cTnT (not significant). The best cutoff values to discriminate between group 1 and group 2 patients were determined with the ROC curves: cTnI=5 microg/L; CKMB mass=20 microg/L; cTnT=0.3 microg/L. Sensitivity, specificity, and positive and negative values for cTnI (5 microg/L) were 91%, 82%, 53%, and 98%, respectively. CONCLUSIONS: There was little differences among cTnI, cTnT, and CKMB after CABG to diagnose myocardial damage as assessed by new Q wave on the ECG. There was a trend of cTnI to be a better discriminator than cTnT, but it did not reach statistical significance.

Case of successful percutaneous stenting of an in situ gastroepiploic-coronary bypass graft.

The in situ or free gastroepiploic artery (GEA) is being used as an arterial conduit for coronary artery bypass surgery (CABG). The recent rapid improvements in stent manufacture, particularly their profile and flexibility, and related equipment, have helped reduce complications of coronary angioplasty. We describe one case of successful stenting of an in situ GEA-posterior descending artery graft. Stenting of an in situ GEA graft may avoid an incomplete result of angioplasty with possible restenosis or the need for multiple surgical revascularization. The use of stents in GEA grafts with 6 Fr soft guiding catheters can be encouraged.

Early versus late coronary stenting following acute myocardial infarction: results of the STENTIM I Study (French Registry of Stenting in Acute Myocardial Infarction).

This study was undertaken to determine the feasibility and safety of coronary stenting in acute myocardial infarction (AMI). In AMI, primary percutaneous transluminal coronary angioplasty (PTCA) is accepted as the preferred method of reperfusion for patients presenting at highly experienced centres. Until recently, however, stenting has been avoided during AMI because of a potential high risk of thrombosis. This prospective observational study carried out in 20 centres and included 648 consecutive patients who underwent PTCA with stent implantation for AMI. Of these 648 patients, 269 (41.5%, Group 1) were dilated early (< 24 hr) after the onset of the symptoms (75% treated by direct PTCA) and 379 (58.5%, Group 2) were dilated between 24 hr and 14 days after AMI. Combined therapy with ticlopidin and aspirin was used after the procedure. Bailout stenting occurred more often in Group 1 than in Group 2 (17% vs. 9.5%)(P < 0.05). Angiographic successful stenting was similar in both groups of patients (96% vs. 97%). During the hospital follow-up period, stent thrombosis occurred in eight patients (3%) in Group 1 and in six patients (1.6%) in Group 2 (NS). There was 14 deaths (5.2%) in Group 1 and 11 deaths (3.9%) in Group 2 (NS). After multivariate analysis bailout stenting was identified as the sole predictor of stent thrombosis (P < 0.0001). Vascular access-site complications occurred in six patients (1%) with no difference between the two groups. This study indicates that patients who receive a coronary stent in AMI can be managed safely with antiplatelet therapy. Randomized studies are needed to determine the precise indication for coronary stenting as an adjunct to primary PTCA.

[Analysis of the diagnostic value of endovascular ultrasound with roc curves. Practical implications]. / Analyse de la performance diagnostique de l'échographie endovasculaire par les courbes ROC. Implications pratiques.

Intravascular ultrasound enables detection of the components of atherosclerotic plaques. The diagnostic value was assessed by ROC (receiver operating characteristic) curves on images acquired in vitro and correlated with the histological findings in 61 arteries. Five questions were asked of each operator; the reply was represented by a continuous variable in order to express all nuances of judgement. The area under the ROC curve, Az, was the criterion of performance (0.5 : chance response : 1.0 : all replies were accurate). Detection of plaque was satisfactory (Az = 0.89). The three layer appearance of muscular arteries was well recognised (Az = 0.94). The fibrous composition of a plaque was only just satisfactory (Az = 0.88) with 38.7% interindividual variability. The lipid composition of the plaque was poorly recognised (Az = 0.76) with large interindividual variability (52.8%) : hypoechogenicity was too ambiguous a sign from the acoustic point of view. A hypoechogenic zone must not be synonymous with a lipid plaque but a cellular zone. Calcium can almost always be detected (Az = 0.98) with a very low interindividual variability (10.7%), fibrohyaline progression of some plaques can be confusing. The authors present a more objective description of endovascular ultrasonographic images. They conclude that the diagnostic performance of 30 MHz intravascular ultrasound is satisfactory but several limitations are apparent in the interpretation of images, especially hypoechogenic zone and hyper-reflective zones with high attenuation.

[Diagnostic value of echocardiography under dobutamine in everyday practice]. / Intérêt diagnostique de l'échocardiographie sous dobutamine en pratique quotidienne.

In order to evaluate the place of dobutamine echocardiography in everyday practice, this test and a stress ECG were performed in 34 patients referred for diagnostic or assessment coronary angiography. Dobutamine, administered in 3-minute stages from 5 to 30 micrograms/kg/min, was well tolerated. The anti-ischaemic treatment was continued in 26 patients before dobutamine echocardiography and in 15 patients before the stress ECG. The electrocardiographic, echocardiographic and angiographic documents were each analysed by 2 independent observers. Dobutamine echocardiography was considered to be positive in the presence of the development of a new abnormality of segmental kinetics or when abnormality of segmental kinetics was identified outside of the territory of infarction. With reference to coronary angiography, the sensitivity of stress ECG and dobutamine echocardiography was 46% and 42%, respectively, and the specificity was 75% and 88%, respectively; the sensitivity of each test was low, probably because of fake tests. The combination of the two tests improved the sensitivity (69%) without altering the specificity (75%). Dobutamine echocardiography could usefully complete a negative stress ICG whenever a false-negative result is suspected to avoir wrongly reassuring some patients and to allow appropriate management.

[Artefacts and intravascular ultrasonography. Analysis and implications for a better reliability in the interpretation of images and measurements]. / Artefacts et échographie endovasculaire. Analyses et implications pour une meilleure fiabilité dans l'interprétation des images et des mesures.

Intravascular ultrasound catheters provide cross-sectional images of vessel walls and surrounding tissues with rotating transducers, and the behavior of ultrasound in heterogeneous media both cause degradation of image quality. Qualitative and quantitative analyses of in vivo studies are operator-dependent and limited by artifacts. We investigated these limitations by an in vitro study on plexiglass phantoms and segments of fresh arteries. We observed, analyzed and interpreted the most specific reasons for image artifacts: geometric distortions, the point spread function of the imaging system and the near field effects. Various practical implications have resulted from this study. Knowledge of the most obvious pitfalls will enable the user to obtain maximum benefits from intravascular ultrasound imaging, and to appreciate its limitations.

Coronary arteries: new design for three-dimensional arterial phantoms.

Few three-dimensional (3D) anthropomorphic phantoms are available for testing 3D reconstruction and quantitation of vessels. The authors built a new realistic model of arteries with use of stereolithography, a computer-aided design and computer-aided manufacturing technique. Each phantom is composed of the physical object and its digital "twin." The entire coronary artery tree and complex stenoses were manufactured with a precision below 0.1 mm.

[Intravascular echographic imaging: experimental validations and limits. An in vitro study]. / Imagerie échographique endovasculaire: validations expérimentales et limitations. Etude in vitro.

Intravascular ultrasound is a new method of visualizing details of vascular pathology, providing (real time) high resolution images of vascular walls. Most of the research on the technique has explored its qualitative and quantitative capabilities to improve the assessment of atherosclerotic vascular disease in vivo. Intravascular ultrasound differs from angiography and angioscopy in its ability to penetrate below the surface of the vessel lumen, demonstrating specific appearances of the distribution and composition of plaque. Image analysis is operator dependent. Although this technology is very promising limitations such as artefacts and loss of image quality in heavily calcified vessels hinder its use. There is hope that this imaging technique may ultimately improve the results of endovascular interventions.

Artifacts in intravascular ultrasound imaging: analyses and implications.

The ability of an intravascular ultrasound catheter to give cross-sectional images of vessel walls and surrounding tissues, and the behavior of ultrasound in heterogeneous media, are at the origin of degradation of image quality. Qualitative and quantitative analyses of in vivo studies are then operator-dependent and are limited by artifacts. We investigated these limitations by an in vitro study on plexiglass phantoms and segments of fresh arteries. We used a 20 MHz transducer mounted on the tip of a 4.8 F catheter and an interventional ultrasound system. The ultrasound beam is reflected onto the rotating transducer at 600 rotations per minute (RPM), creating 360 degrees real-time images (10 images/second). We then observed, analyzed and interpreted the most specific reasons for image artifacts: geometric distortions, multiple echoes, the point spread function (PSF) of the imaging system, near-field effects, "petal-shaped" effect, and ultrasound speckle. Various practical implications have resulted from this study. Only a thorough knowledge of how to avoid some of the most obvious pitfalls will enable the user to obtain maximum benefits from intravascular ultrasound imaging, and to appreciate its limitations.

[Left auricular hypertrophy in aortic stenosis in adults]. / L'hypertrophie auriculaire gauche dans le rétrécissement aortique orificiel de l'adulte.

Left atrial hypertrophy (LAH) was noted from the electrocardiograms of 72 of 98 adult patients (81%) who underwent hemodynamic evaluation of calcified aortostenosis (CAS). The relations between LAH and clinical, echographic and hemodynamic findings are specified. The frequency of LAH was not higher in cases of a history of hypertension, angina pectoris, lipothymia or exercise-induced syncope. In contrast, dyspnea was more frequently associated with LAH (84%) than not (17%). An approximately linear relation was seen between LAH and the mean pulmonary capillary pressure, the mean rate of circumferential decrease (RCF), the coefficient of muscle rigidity (ks of Mirsky), the left ventricular mass (LVM) and the left ventricle-aorta gradient. LAH is, therefore, a frequent sign in patients presenting CAS. Its origin is multifactorial, with a predominance of increased mean capillary pressure in cases of clinical signs of poor safety.

[Left auricular dilatation in calcified aortic stenosis in adults]. / Dilatation auriculaire gauche dans le rétrécissement aortique orificiel calcifié de l'adulte.

Two groups of patients of comparable age, one comprising 12 subjects without detectable cardiac disease and the other comprising 38 patients with calcific aortic stenosis (CAS) underwent clinical, electrocardiographic, echocardiographic and haemodynamic studies to assess the degree and significance of left atrial hypertrophies in CAS. The volume of the left atrium (LA) was globally increased in CAS (maximum volume 68 per cent: 26/38) and LA ejection fraction was decreased in 60 per cent of patients (23/38). However, the maximum volume was only moderately greater than that of normal subjects (+38 per cent). The most specific non-invasive investigation for left atrial assessment is echocardiography. There was a linear relationship between LA angiographic volume and echocardiographic antero-posterior dimension (r = 0.43; p less than 1 x 10(-2)). The duration of the P wave in S2 was a specific (75 per cent) but relatively insensitive (27 per cent) sign of LA dilatation in pure CAS. On the other hand, the Morris index based on the surface of the P terminal force in V1 was quite sensitive (77 per cent) but not very specific (25 per cent). The maximum LA volume was not related to left ventricular volume, the severity of CAS, diastolic indices of compliance or left ventricular mass. However, the minimum LA volume (after atrial systole) was related to left ventricular end diastolic (r = 0.35, p less than 0.05) and end systolic volume (r = 0.34, p less than 0.05). The LA ejection fraction was inversely related to mean pulmonary capillary pressure (r = 0.34, p less than 5 x 10(-2).(ABSTRACT TRUNCATED AT 250 WORDS)

[Hemodynamic effects of intravenous magnesium sulfate in man]. / Effets hémodynamiques du sulfate de magnésium intraveineux chez l'homme.

The haemodynamic effects of a single 3 g dose of magnesium sulfate administered by slow (1 min) intravenous injection were evaluated in 16 patients with coronary disease about to be explored by coronary arteriography. The haemodynamic effects were transient, with maximal values at the end of the injection and return to baseline values within less than 3 min. They consisted of peripheral vasodilatation with a decrease in systolic aortic pressure (128 +/- 18 mmHg versus 113 +/- 17 mmHg, p less than 0.05), an increase of cardiac index (3.0 +/- 0.4 versus 3.8 +/- 0.06 1/min/m2, p less than 0.001) and a fall in peripheral arterial resistance (1168 +/- 203 versus 919 +/- 29 dyn/s/cm-5, p less than 0.01). This action was accompanied by a moderate increase in contractility (Vmax) (1.63 +/- 0.34 versus 1.87 +/- 0.47 CIR/s, p less than 0.01) without changes in the relaxation index T (37 +/- 8 versus 67 +/- 9 s-1, NS), but with concomitant increase in heart rate (80 +/- 12 versus 67 +/- 10 beats/min, p less than 1.10(-4]. It is concluded that the haemodynamic effects of magnesium sulfate are moderate and transient and that this substance can be used safely as antiarrhythmic agent, even in case of marked deterioration of the left ventricular function.