No post-conditioning in the human heart with thrombolysis in myocardial infarction flow 2-3 on admission.

AIMS: Proof-of-concept evidence suggests that mechanical ischaemic post-conditioning (PostC) reduces infarct size when applied immediately after culprit coronary artery re-opening in ST-elevation myocardial infarction (STEMI) patients with thrombolysis in myocardial infarction 0-1 (TIMI 0-1) flow grade at admission. Whether PostC might also be protective in patients with a TIMI 2-3 flow grade on admission (corresponding to a delayed application of the post-conditioning algorithm) remains undetermined. METHODS AND RESULTS: In this multi-centre, randomized, single-blinded, controlled study, STEMI patients with a 2-3 TIMI coronary flow grade at admission underwent direct stenting of the culprit lesion, followed (PostC group) or not (control group) by four cycles of (1 min inflation/1 min deflation) of the angioplasty balloon to trigger post-conditioning. Infarct size was assessed both by cardiac magnetic resonance at Day 5 (primary endpoint) and cardiac enzymes release (secondary endpoint). Ninety-nine patients were prospectively enrolled. Baseline characteristics were comparable between control and PostC groups. Despite comparable size of area at risk (AAR) (38 ± 12 vs. 38 ± 13% of the LV circumference, respectively, P = 0.89) and similar time from onset to intervention (249 ± 148 vs. 263 ± 209 min, respectively, P = 0.93) in the two groups, PostC did not significantly reduce cardiac magnetic resonance infarct size (23 ± 17 and 21 ± 18 g in the treated vs. control group, respectively, P = 0.64). Similar results were found when using creatine kinase and troponin I release, even after adjustment for the size of the AAR. CONCLUSION: This study shows that infarct size reduction by mechanical ischaemic PostC is lost when applied to patients with a TIMI 2-3 flow grade at admission. This indicates that the timing of the protective intervention with respect to the onset of reperfusion is a key factor for preventing lethal reperfusion injury in STEMI patients. CLINICAL TRIAL NUMBER: NCT01483755.

Acute stroke and heart attack management within a four-hour time window.

BACKGROUND AND PURPOSE: Although brain embolism is a uncommon complication of myocardial infarction, sequential treatment of cerebral and coronary artery occlusion within a 4-hour time window is unusual. SUMMARY: of case A 60 year-old man experienced successful intravenous recombinant thrombolysis (tPA) for acute middle cerebral artery (MCA) occlusion followed by efficient angioplasty stenting of a troponin-negative coronary occlusion which, while painless, involved clear electrocardiographic abnormalities. Both pathologies were treated within a 4-hour time window. CONCLUSION: Acute brain and heart ischemia may be successfully treated within a 4-hour time window, thanks to an efficient multidisciplinary approach.

Morphological and biomechanical aspects of vulnerable coronary plaque.

Vulnerable plaque morphology has been described by gross pathology and intravascular ultrasound, but morphological criteria cannot fully explain vulnerability, which involves four distinct factors: 1) inflammatory and biological processes; 2) geometry; 3) composition; and 4) hemodynamic stress. These last three aspects underlie the biomechanical study of vulnerable plaque. By virtue of the nature of their evolution, atherosclerotic plaques tend to be excentric, and this is a crucial morphological feature, causing circumferential stress to peak in very specific juxta-luminal locations, where it can exceed the rupture threshold of collagen, the basic constituent of arterial architecture. The lipido-necrotic core covered by a fibrous cap, formed in young plaques, is another morphological feature, which, can also increase and concentrate circumference stress in the juxta-luminal fibrous cap. The larger the lipid core, the thinner the fibrous cap and the greater is the stress. There are also inflammatory processes in such areas, which tend to reduce cap thickness. Ruptures occur when this thickness falls below 65 microns. Heart rate, blood pressure and pulse pressure are all biomechanical factors affecting vulnerable arterial walls, increasing circumferential stress and material fatigue. Vulnerable plaques are almost always associated with positive arterial remodeling. Numerical simulation has shown such so-called compensatory remodeling to be exclusively due to the healthy arc stretching in vulnerable plaques. Positive remodeling is optimal when the healthy arc is around 170 degrees, which keeps the lumen area relatively stable as long as the plaque does not exceed 40% to 50%. This mechanism does not apply to concentric plaques. In conclusion, the mechanism of vulnerable plaque rupture is highly complex and multifactorial. This complexity more or less precludes prediction in individual cases: we are in the realms of chaos theory and acute sensitivity to initial conditions. The greatest caution is therefore required in any attempt to predict rupture from diagnostic imagery, which provides only morphological data on plaque's nature.

[Myocardial bridging and coronary spasm on effort]. / Pont myocardique et spasme coronaire à l'effort.

The discovery of myocardial bridging during coronary angiographies is common. Yet these bridges are rarely the origin of acute coronary syndrome. We report the case of an active 45 year old man with no cardiovascular risk factors who had acute coronary syndrome. Emergency coronary angiography just revealed two myocardial bridges on the anterior interventricular artery which did not explain this acute episode. A subsequent second angiogram together with endocoronary echography demonstrated that there was no atheroma and a methergin test set off diffuse coronary spasm. The association of myocardial bridging and coronary spasm has only rarely been reported in the literature. We describe the clinical, therapeutic and prognostic characteristics.

Multiple atherosclerotic plaque rupture in acute coronary syndrome: a three-vessel intravascular ultrasound study.

BACKGROUND: To test the hypothesis of general atherosclerotic plaque destabilization during acute coronary syndrome (ACS), the present study sought to analyze the 3 coronary arteries by systematic intravascular ultrasound scan (IVUS). METHODS AND RESULTS: Seventy-two arteries were explored in 24 patients referred for percutaneous coronary intervention after a first ACS with troponin I elevation. Fifty plaque ruptures (mean, 2.08 per patient; range, 0 to 6) were diagnosed by the association of a ruptured capsule with intraplaque cavity. Plaque rupture on the culprit lesion was found in 9 patients (37.5%). At least 1 plaque rupture was found somewhere other than on the culprit lesion in 19 patients (79%). These lesions were in a different artery than the culprit artery in 70.8% and were in both other arteries in 12.5% of these 24 patients. Complete IVUS examination of all 3 coronary axes in patients who had experienced a first ACS revealed that multiple atherosclerotic plaque ruptures were detected by IVUS; these multiple ruptures were present simultaneously with the culprit lesion; they were frequent and located (in three quarters of cases) on the 3 principal coronary trunks; and the multiple plaque ruptures in locations other than on the culprit lesion were less severe, nonstenosing, and less calcified. CONCLUSION: Although one single lesion is clinically active at the time of ACS, the syndrome seems nevertheless associated with overall coronary instability.

[Morphological and functional characteristics of the culprit coronary artery in acute coronary syndrome]. / Aspects morphologiques et fonctionnels de l'artère coronaire coupable d'un syndrome coronaire aigu.

In the catheter laboratory, faced with a patient with unstable angina, the problem is not the diagnosis of epicardial coronary artery stenosis but rather the atherothrombotic complexity of the stenosis and the identification of other less stenotic lesions on angiographically normal or nearly normal segments. The authors describe two appearances with morphological analysis of the vulnerable or unstable plaque and functional analysis of coronary artery vasomotricity. Acute coronary syndromes due to a clearly stenotic atherothrombotic plaque on angiography pose no diagnostic problems. However, an acute coronary syndrome may be more difficult to assess when angiography shows only simple irregularities of the lumen or no lesions at all. In these cases, angiography is said to be normal and the coronary arteries are considered to be possibly "healthy". Evaluation of the vessels' vasomotricity is especially valuable in this context. Using pharmacological stress tests, endovascular ultrasonography is a complementary diagnostic tool which allows identification of the unstable atheromatous process or of a partial atherothrombosis masked by positive remodelling process. These tests may also indicate the optimal treatment.

[Emergent transcatheter aortic valve implantation in a patient with bicuspid aortic valve stenosis in cardiogenic shock]. / Choc cardiogénique sur bicuspidie aortique sténosante traité par remplacement valvulaire aortique percutané en urgence.

Transcatheter aortic valve implantation is a therapeutic option for high-risk patients with severe aortic valve stenosis and with cardiac symptoms. This procedure requires the preliminary evaluation by a "heart team" and presents some contraindications. We report the case of a 58-year-old man with severe bicuspid aortic valve stenosis and cardiogenic shock. In spite of contraindications and because of the failure of balloon aortic valvuloplasty, transcatheter aortic valve implantation was performed in emergency.

In-vivo prediction of human coronary plaque rupture location using intravascular ultrasound and the finite element method.

BACKGROUND: Spontaneous rupture of atherosclerotic plaques is known to be involved in the mechanism leading to acute coronary syndromes. Means to detect plaques prone to rupture and predict rupture location would then be very valuable for clinical diagnosis. DESIGN: In this study, finite element (FE) analysis based on intravascular ultrasound (IVUS) images of atherosclerotic arteries was used to predict in-vivo plaque rupture locations. In four patients with coronary artery diseases, IVUS images were recorded before and after balloon angioplasty. Pre-angioplasty images were recorded after injection of ATP. This caused a brief drop of arterial blood pressure down to values of about 20 mmHg, and thus allowed the recording of the unloaded configurations of arteries used to initiate FE analysis. Plaque rupture was triggered by balloon inflation (coronary angioplasty). FE simulations were performed under physiological loading conditions. Stress distributions within the plaque and the arterial wall were determined. The corresponding stress maps are presented. RESULTS: Circumferential tensile peak stress areas were compared with plaque rupture locations on postangioplasty IVUS images. They were found to coincide in all four studied cases. CONCLUSION: Our results agreed with those reported in previous studies based on ex-vivo postnecropsic data and showed the feasibility of in-vivo prediction of atherosclerotic plaque rupture location.

Mechanical properties of coronary stents determined by using finite element analysis.

The mechanical function of a stent deployed in a damaged artery is to provide a metallic tubular mesh structure. The purpose of this study was to determine the exact mechanical characteristics of stents. In order to achieve this, we have used finite-element analysis to model two different type of stents: tubular stents (TS) and coil stents (CS). The two stents chosen for this modeling present the most extreme mechanical characteristics of the respective types. Seven mechanical properties were studied by mathematical modeling with determination of: (1) stent deployment pressure, (2) the intrinsic elastic recoil of the material used, (3) the resistance of the stent to external compressive forces, (4) the stent foreshortening, (5) the stent coverage area, (6) the stent flexibility, and (7) the stress maps. The pressure required for deployment of CS was significantly lower than that required for TS, over 2.8 times greater pressure was required for the tubular model. The elastic recoil of TS is higher than CS (5.4% and 2.6%, respectively). TS could be deformed by 10% at compressive pressures of between 0.7 and 1.3 atm whereas CS was only deformed at 0.2 and 0.7 atm. The degree of shortening observed increases with deployment diameter for TS. CS lengthen during deployment. The metal coverage area is two times greater for TS than for CS. The ratio between the stiffness of TS and that of CS varies from 2060 to 2858 depending on the direction in which the force is applied. TS are very rigid and CS are significantly more flexible. Stress mapping shows stress to be localized at link nodes. This series of finite-element analyses illustrates and quantifies the main mechanical characteristics of two different commonly used stents. In interventional cardiology, we need to understand their mechanisms of implantation and action.

Experimental assessment of new stent technologies: validation of a comparative paired rabbit iliac artery study model.

Preventing coronary in-stent restenosis is a major challenge for physicians and industry. To assess new stent technologies, a comparative paired iliac artery model in rabbits is proposed. One tubular stent was implanted in each external iliac artery in 12 rabbits (i.e., 24 stents). An artery overdilatation level of 20% was strictly observed. Restenosis was examined at 30 days by angiography, intravascular ultrasound (IVUS) examination, and histomorphometry. On quantitative angiography, the mean loss of angiographic diameter was 9.8 +/- 4.4% in the right as compared to 9.3 +/- 55% in the left artery (p = 0.75). On IVUS, the volume of intrastent neointimal proliferation was 26.6 +/- 4.9 mm(3) in the right and 25.8 +/- 3.5 mm(3) in the left artery (p = 0.58). In histomorphometry, the neointimal proliferation area was 0.78 +/- 17 mm(2) in the right and 0.76 +/- 0.17 mm(2) in the left artery (p = 0.87). Intrastent neointimal proliferation was comparable between the left and right arteries of all rabbits. The model has three main advantages: (1) arterial dilatation and thus arterial wall aggression are controlled, (2) pairing makes each animal its own control subject, and (3) the statistical power for comparative testing is maximized. The model enables the effect of a new drug-delivery device to be assessed.

[The vulnerable plaque: a necessary concept in the management of atherothrombosis]. / La plaque vulnérable: un concept nécessaire dans la prise en charge de l'athérothrombose.

The advance of cardiology has improved the prognosis of atherothrombosis through direct diagnosis and early management, but the global incidence of atherothrombotic events has been modified only slightly. Currently, although the stenosing effect of atherosclerosis is well known and if treated hardly poses a problem, the unpredictable risk of arterial thrombosis continues to cause the seriousness of the disease in as much as it is not linked to the degree of stenosis. The initiation of thrombosis progresses via destabilisation phenomena of atherosclerotic plaques with rupture or erosion of the capsule. The identification of plaques "at risk" of instability, so-called "vulnerable" plaques, is thus now a fundamental concept. Thanks to anatomo-pathology, certain morphological and functional criteria of these vulnerable plaques are better understood and are starting to find a clinical resonance. An inflammatory syndrome scenario, thin capsule, and a large lipidic heart associated with an as yet quiescent atherosclerotic plaque are predictive elements of acute coronary syndrome. These elements show promise and an already combined biological and morphological approach will certainly be at the heart of clinical research for years to come.

[Qualitative and quantitative descriptions of the mechanisms of action of the angioplasty balloon on coronary stenosis. An endovascular ultrasonic study]. / Descriptions qualitatives et quantitatives des mécanismes d'action du ballon d'angioplastie sur la sténose coronaire. Etude échographique endovasculaire.

The barotrauma induced by inflation of the balloon on an obstructive atherosclerotic plaque induces several distinct, complex effects. The object of this study was to describe these mechanisms based on endovascular echographic sections of coronary stenoses before and after balloon angioplasty. The 32 lesions analysed were richly cellular (81.2%) and associated with calcifications in 31% of cases. The remodelling index before angioplasty was used to individualize a majority of lesions with chronic arterial constriction (56.2%). The modelling of the plaque (dilatation or constriction) had no effect on the final luminal result. Global analysis of the endoluminal gain (4.38 +/- 2.28 mm2) showed that it was mainly due to reduction of plaque surface (78.2% of gain) without prejudging the mechanism, and less due to expansion of the global arterial surface (21.8% of the gain). The type of remodelling affected the mechanisms of action of balloon angioplasty. Dissection was present in 53.1% of cases. Fragmentation of the plaque with embolisation is a common phenomenon (28% of cases). The authors conclude that there are four mechanisms which coexist: 1) Reduction of plaque thickness cannot physically correspond to simple compression of tissue. The plaque is redistributed longitudinally. 2) Arterial expansion only plays a minor part in endoluminal gain. 3) Plaque rupture is directly related to the acute increase in wall stress often exceeding the thresholds of rupture of its components. Finally, 4) embolisation by parietal fragmentation, a mechanism often unknown or ignored which plays an essential part in the potentially deleterious effects.

[Ischemic preconditioning: concept of endogenous myocardial protection]. / Le préconditionnement ischémique: concept d'une protection myocardique endogène.

Preconditioning is a temporary tolerance to ischaemia acquired by the myocardium after a short period of ischaemia. It results in the limitation of the infarct size induced by prolonged coronary occlusion. The mechanism of this cytoprotection remains poorly understood. The A1 adenosine receptors, the ATP-sensitive potassium channels and protein-kinase C seem to play prominent roles. The effects of preconditioning on the complications of ischaemia/reperfusion such as myocardial stunning, ventricular arrhythmias or decreased coronary reserve are not well known. Several studies suggest that the cytoprotection resulting from preconditioning could be applied to human myocardium and constitute a preventive anti-ischaemic therapy during coronary angioplasty, cardiac surgery or the conservation of transplant grafts.

[Multiple ruptures of atherosclerotic plaques in acute coronary syndrome. Endocoronary ultrasonography study of three arteries]. / Ruptures multiples de plaques d'athérosclérose dans les syndromes coronaires aigus. Etude échographique endocoronaire des trois artères.

The aim of this study was to assess the three coronary arteries systematically by endocoronary ultrasonography in patients with unstable angina to check the hypothesis of global destabilisation of atherosclerotic plaques in acute coronary syndromes (ACS). Sixty two coronary arteries were examined (2.6 per patient). Fifty plaque ruptures were diagnosed (2.08 per patient). Rupture of a plaque of the culprit lesion of the ACS was clearly detected in 9 patients (37.5%). At least one ruptured plaque on a site other than the culprit lesion was observed in 19 patients (79%), on another artery in 70.8% of cases and on two other arteries in 12.5% of cases. A complete endocoronary ultrasonic examination of the three coronary arteries in patients with a first ACS demonstrated that: multiple atherosclerotic plaque rupture may be detected by endocoronary ultrasonography; these multiple plaque ruptures occur simultaneously with the culprit lesion; they are frequent and can be situated on the three main coronary vessels and multiple plaque rupture other than the culprit lesion are less severe, non stenotic and less calcified. Thus, although a single lesion is clinically symptomatic, ACS seems to be associated with global coronary instability.

[Sudden death by coronary spasm: a particular and often unrecognised clinical entity]. / Mort subite par s pasme coronaire: une entité particulière, trop souvent méconnue.

The authors report 3 cases of resuscitated sudden death in which the investigations clearly showed coronary spasm. This was demonstrated by systematic coronary angiography with an ergometric test. Two patients underwent electrophysiological investigations which were normal. The three patients were prescribed long-term calcium antagonist therapy and one of them underwent coronary angioplasty. With a follow-up of 6 months to 3 years, there was no clinical recurrence or documented arrhythmia. A review of the literature shows that this is a cause of sudden death which is probably underestimated and unrecognised. Electrophysiological investigations often give disappointing results and medical therapy is the keystone of treatment. Coronary angioplasty and implantation of an automatic defibrillator are second-line treatments reserved to forms refractory to medical therapy.

[Coronary pressure measurement for functional evaluation and treatment of intermediate angiographic stenosis]. / Apport des guides de pression intracoronaire pour l'évaluation fonctionnelle et le traitement des sténoses angiographiques intermédiaires.

Accurate understanding of the physiopathology of a coronary stenosis is a major objective in management during diagnostic coronary angiography. Measurement of fractional flow reserve (FFR) by coronary pressure measurement is a reliable method for evaluating the functional consequences of a lesion of the myocardium. This retrospective monocentric study of 114 patients showed that routine coronary pressure measurement for assessing the functional consequences of intermediate (30 to 70% stenosis) lesions or those of ambiguous topography: was necessary in 4% of diagnostic coronary angiographies enabling an immediate management decision. Using this method, 34% of complementary investigations were not performed (stress test, myocardial scintigraphy, dobutamine stress echocardiography). Seventeen per cent of unnecessary angioplasties were also avoided so that acute coronary event were also avoided when lesions with a FFR >0.75 were not treated by angioplasty. A 10-14% reduction in cost was achieved compared with a strategy of systematic angioplasty in respectively mono- or multivessel disease patients and 39% compared with performing ambulatory myocardial scintigraphy in patients with multivessel disease.

[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).

[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.

[Predictive value of glycemia in acute coronary syndromes]. / Valeurs prédictives de la glycémie dans les syndromes coronaires aigus. Revue de la littérature.

Intravenous insulin therapy is used in diabetic patients at the acute phase of coronary syndrome (ACS). However, hyperglycemia in diabetic patients is a powerful predictive factor for patient outcome as it is associated with a doubling of in-hospital mortality and poor long-term prognosis. Recent studies involving non-diabetic patients show that even mild hyperglycemia in the setting of ACS is also a predictive factor of in-hospital mortality. Moreover, the new entity called impaired fasting glucose (IFG) (6.1 to 7 mmol/L) is not only an independent factor of mortality for coronary patients, but very recently has also been associated with a doubling of the risk of in-hospital mortality in the setting of ACS. Admission as well as follow-up glycaemia are fundamental parameters in ACS on the one hand for their prognostic value, and on the other end as a diagnostic tool in determining the presence of diabetes or IFG.

[Platypnea-orthodeoxia syndrome: case report]. / Le syndrome de platydéoxie-orthopnée : à propos d'un cas.

We report the case of an 80-year-old woman with symptomatic postural hypoxaemia caused by a right-to-left shunt through a patent foramen ovale. The hypoxaemia was enhanced by the supine position and disappeared in upright position. Potential mechanisms underlying postural variations of the shunt seemed to be similar to those describe in platypnea-orthodeoxia syndrome. Patient became asymptomatic after shunt resolution.