Impact of left atrial appendage morphology on thrombus formation in TAVI patients with atrial fibrillation.

PURPOSE: We aimed to correlate left atrial appendage (LAA) morphology with thrombus formation in patients with severe aortic valve stenosis and atrial fibrillation. METHODS: We analyzed LAA morphology and the prevalence of a thrombus in 231 patients with atrial fibrillation and severe aortic valve stenosis that were referred for pre-interventional CT scan before trans-catheter aortic valve implantation (TAVI) between 2016 and 2018. In addition, we documented neuro-embolic events depending on the presence of LAA thrombus within a follow-up of 18 months. RESULTS: The overall distribution of different LAA morphologies was chicken-wing 25.5%, windsock 51.5%, cactus 15.6% and cauliflower 7.4%. Compared to chicken-wing morphology, patients with non-chicken-wing morphology showed a significantly higher thrombus rate (OR: 2.48, 95%; CI 1.05 to 5.86, p = 0.043). Within the 50 patients with a LAA thrombus, we observed chicken-wing (14.0%), windsock (62.0%), cactus (16.0%) and cauliflower (8.0%) configuration. In patients with LAA thrombus those with chicken-wing configuration have a higher risk (42.9%) to develop neuro-embolic events compared to non-chicken-wing configuration (20.9%). CONCLUSION: We found a lower LAA thrombus rate in patients with chicken-wing morphology compared to patients with non-chicken-wing configuration. However, in the presence of thrombus, those patients with chicken-wing morphology showed a doubled risk for neuro-embolic events compared to patients with non-chicken-wing morphology. These results must be confirmed in larger trials but underline the importance of LAA evaluation in thoracic CT scans and could have an impact on the anticoagulation management.

Assessment of global and regional left ventricular function using 64-slice multislice computed tomography and 2D echocardiography: a comparison with cardiac magnetic resonance.

OBJECTIVES: To compare the assessment of global and regional left ventricular (LV) function using 64-slice multislice computed tomography (MSCT), 2D echocardiography (2DE) and cardiac magnetic resonance (CMR). METHODS: Thirty-two consecutive patients (mean age, 56.5+/-9.7 years) referred for evaluation of coronary artery using 64-slice MSCT also underwent 2DE and CMR within 48h. The global left ventricular function which include left ventricular ejection fraction (LVEF), left ventricular end diastolic volume (LVdV) and left ventricular end systolic volume (LVsV) were determine using the three modalities. Regional wall motion (RWM) was assessed visually in all three modalities. The CMR served as the gold standard for the comparison between 64-slice MSCT with CMR and 2DE with CMR. Statistical analysis included Pearson correlation coefficient, Bland-Altman plots and kappa-statistics. RESULTS: The 64-slice MSCT agreed well with CMR for assessment of LVEF (r=0.92; p<0.0001), LVdV (r=0.98; p<0.0001) and LVsV (r=0.98; p<0.0001). In comparison with 64-slice MSCT, 2DE showed moderate correlation with CMR for the assessment of LVEF (r=0.84; p<0.0001), LVdV (r=0.83; p<0.0001) and LVsV (r=0.80; p<0.0001). However in RWM analysis, 2DE showed better accuracy than 64-slice MSCT (94.3% versus 82.4%) and closer agreement (kappa=0.89 versus 0.63) with CMR. CONCLUSION: 64-Slice MSCT correlates strongly with CMR in global LV function however in regional LV function 2DE showed better agreement with CMR than 64-slice MSCT.

Acute tension pneumopericardium due to perforated gastric ulcer without diagnostic radiographic findings 72 h before perforation.

INTRODUCTION: Acute tension pneumopericardium due to gastric perforation is a rare and often lethal condition. Only a few case reports have been described in the literature. Diagnosis based on clinical evaluation is difficult and it is usually made incidentally upon computed tomography (CT) or plain radiography of the chest. Since cardiac tamponade caused by pneumopericardium is life-threatening, immediate diagnosis and emergent therapy is vital. CASE REPORT: We report a 75-year-old male with peptic ulcer disease associated with perforation of the pericardium and acute shock. It is the first reported case with a series of two computed tomograms performed during the 72 h preceding the acute onset of tension pneumopericardium. No radiographic evidence of ulcer perforation was present in the three days prior to the acute event. DISCUSSIONS: Gastric ulcer perforation into the pericardium is rare and could not be detected by CT scan prior the deletorious event. Pneumopericardium seems to be fateful and could not be foreseen by clinical or radiological findings..

Application of the Bogossian formula for evaluation of the QT interval in pacemaker patients with stimulated left bundle branch block.

BACKGROUND: The presence of left bundle branch block (LBBB) represents a particular challenge in properly measuring the QT interval. Here we demonstrate the applicability of the "Bogossian formula" in pacemaker patients with LBBB due to apical or nonapical right ventricular (RV) pacing and preserved left ventricular function. METHODS: A total of 163 patients with a cardiac one- or two-chamber pacemaker were included in this prospective, multicentre observational study. Twelve-lead ECG recordings were obtained during both intrinsic rhythm and RV pacing with induced LBBB. The QT interval measured during LBBB was corrected using the Bogossian formula to obtain the "modified QT" (QTm). The QTmc interval was calculated with the Bazett formula, and this was compared with the QTc interval during intrinsic rhythm. RESULTS: Eighty-three patients (78 ± 9 years; male n = 83) with apical and eighty patients (71 ± 13 years; male n = 80) with non-apical RV pacing were included in this study. In the apical group the QTmc was determined to be 444 ± 39 ms in paced rhythm and the QTc interval 413 ± 36 ms in intrinsic rhythm. In the non-apical group these values were 430 ± 34 ms in paced and 416 ± 32 ms in intrinsic rhythm. CONCLUSION: The Bogossian formula is a reliable tool for QTc interval evaluation in pacemaker patients with LBBB due to apical or non-apical RV pacing. However, an overestimation of 30 ms should be included in the calculation.

Accuracy of 64-row multidetector computed tomography in detecting coronary artery disease in 134 symptomatic patients: influence of calcification.

BACKGROUND: The new 64-row multidetector computed tomography (CT)-assisted angiography can now detect coronary artery disease with shorter breath-hold time and at faster heart rates for symptomatic patients. We aim to determine if the 64-row scanner can also overcome limitations due to mild to moderate calcification. METHODS: Scheduled for conventional coronary angiography, 134 symptomatic patients underwent multidetector CT-assisted angiography within 3 months. Patients were divided into those with low or high calcium score (median score 142) by modified Agatston formula: group A calcium score <142 Agatston score (68 patients, mean age 53 years, heart rate 62 beat/min) and group B calcium score > or = 142 Agatston score (66 patients, mean age 57 years, heart rate 62 beat/min). Eleven major coronary segments were evaluated. RESULTS: In group A, 93.6% of segments were evaluable with 97.3% correlation. Segment-by-segment analyses for sensitivity, specificity, and positive and negative predictive values were 85.4%, 98.1%, 76.7%, and 99.2%, respectively. For group B, 86.9% of segments were evaluable with 90.5% correlation. Sensitivity, specificity, and positive and negative predictive values were 79.9%, 92.8%, 78.8%, and 93.5%, respectively. CONCLUSIONS: The 64-slice multidetector CT coronary angiography can reliably detect the presence of significant coronary stenosis in symptomatic patients with mild calcification, but remains limited by moderate to heavy calcification.

Proximal culprit lesion and coronary artery occlusion independently predict the risk of microvascular obstruction in acute myocardial infarction.

Microvascular obstruction (MO) and coronary flow have been independently described to have a high prognostic impact after acute myocardial infarction (AMI). Their interdependence has not been precisely elucidated, so far. Aim of this study was to investigate the impact of coronary flow on the occurrence of MO in patients with AMI. 336 patients with revascularized AMI were examined by cardiac magnetic resonance imaging. Patients were categorised into two groups based on the presence of MO. Procedural characteristics and marker of infarct size were analyzed. MO was present in 110 (33 %) and absent in 226 (67 %) patients. Both groups differed significantly regarding pre- and post-interventional thrombolysis in myocardial infarction (TIMI) flow. After multivariable regression analysis pre-interventional TIMI-flow 0, proximal culprit lesion, post-interventional TIMI-flow

Enhanced cardiac contractility after gene transfer of V2 vasopressin receptors In vivo by ultrasound-guided injection or transcoronary delivery.

BACKGROUND: Systemic levels of arginine vasopressin (AVP) are increased in congestive heart failure, resulting in vasoconstriction and reduced cardiac contractility via V(1) vasopressin receptors. V(2) vasopressin receptors (V2Rs), which promote activation of adenylyl cyclase, are physiologically expressed only in the kidney and are absent in the myocardium. Heterologous expression of V2Rs in the myocardium could result in a positive inotropic effect by using the endogenous high concentrations of AVP in heart failure. METHODS AND RESULTS: We tested gene transfer with a recombinant adenovirus for the human V2R (Ad-V2R) to stimulate contractility of rat or rabbit myocardium in vivo. Ultrasound-guided direct injection or transcoronary delivery of adenovirus in vivo resulted in recombinant receptor expression in the myocardial target area, leading to a substantial increase in [(3)H]AVP binding. In 50% of the cardiomyocytes isolated from the directly injected area, single-cell shortening measurements detected a significant increase in contraction amplitude after exposure to AVP or the V2R-specific desmopressin (DDAVP). Echocardiography of the target myocardial area documented a marked increase in local fractional shortening after systemic administration of DDAVP in V2R-expressing animals but not in control virus-treated hearts. Simultaneous measurement of global contractility (dP/dt(max)) confirmed a positive inotropic effect of DDAVP on left ventricular function in the Ad-V2R-injected animals. CONCLUSIONS: Adenoviral gene transfer of the V2R into the myocardium increases cardiac contractility in vivo. Heterologous expression of cAMP-forming receptors in the myocardium could lead to novel strategies in the therapy of congestive heart failure by bypassing the desensitized beta-adrenergic receptor-signaling cascade.

PlA polymorphism of platelet glycoprotein IIIa and risk of restenosis after coronary stent placement.

BACKGROUND: Platelets play a central role in the process of restenosis after percutaneous coronary interventions. A polymorphism of platelet glycoprotein IIIa (PlA) has been associated with a higher risk of coronary thrombosis. We designed this prospective study to test the hypothesis that PlA polymorphism of glycoprotein IIIa is associated with an increased risk for restenosis after coronary stent placement. METHODS AND RESULTS: The study included 1150 consecutive patients with successful coronary stent placement and 6-month follow-up with coronary angiography. The end point of the study was the incidence of angiographic restenosis (>/=50% diameter stenosis) at follow-up. Of the 1150 patients, 72.5% were homozygous for PlA1, 24.7% were heterozygous (PlA1/A2), and 2.8% were homozygous for PlA2. Patients with the PlA2 allele demonstrated a significantly higher restenosis rate than did those without (47% versus 38%; OR, 1.42; 95% CI, 1.09 to 1.84). The risk was highest in homozygous carriers of PlA2 (53.1% restenosis rate). After adjustment for several clinical and angiographic characteristics, the presence of the PlA2 allele remained a significantly independent risk factor for restenosis (adjusted OR, 1.35; 95% CI, 1.07 to 1.70). The influence of the PlA2 allele on restenosis was stronger in women. Women with PlA2 had a restenosis rate of 52% compared with the 33% incidence among women homozygous for PlA1 (OR, 2.21; 95% CI, 1.27 to 3.85). CONCLUSIONS: This study showed a significant association between the PlA polymorphism of glycoprotein IIIa and the risk of restenosis after coronary stent placement. The risk was more pronounced in patients homozygous for PlA2 allele and in female patients.

Previous cytomegalovirus infection and restenosis after coronary stent placement.

BACKGROUND: Reactivated cytomegalovirus may promote neointima formation after percutaneous coronary interventions by facilitating cell cycle progression through inhibition of the eukariotic tumor suppressor protein p53. This prospective study sought to investigate the effect of previous cytomegalovirus infection on restenosis after coronary stenting. METHODS AND RESULTS: In 551 consecutive patients with successful stent placement, we determined cytomegalovirus IgG titers. Primary and secondary end points were the rate of angiographic restenosis at 6 months and the rate of target vessel reintervention at 1 year, respectively. Three hundred forty patients (62%) had a positive cytomegalovirus IgG titer. We obtained angiographic follow-up in 82% of all patients. Angiographic restenosis rate was 28.7% in patients with positive cytomegalovirus titers and 34.6% in patients with negative titers (P=0.18). Between the groups with and without positive cytomegalovirus titers, there were no significant differences in late lumen loss (1.16+/-0.90 mm and 1.23+/-0.86 mm, respectively, P=0.44). Target vessel reintervention was performed in 16.8% of the patients with positive cytomegalovirus titers and in 17.5% of those without (P=0.82). Even after correction for potential confounding variables by multivariate analysis, positive cytomegalovirus titers did not manifest as a predictor of angiographic restenosis (adjusted odds ratio [95% confidence interval], 0.78 [0.52 to 1.19]). CONCLUSIONS: Previous cytomegalovirus infection does not carry an increased risk of restenosis after stenting.

Intracoronary stenting and angiographic results: strut thickness effect on restenosis outcome (ISAR-STEREO) trial.

BACKGROUND: Increased thrombogenicity and smooth muscle cell proliferative response induced by the metal struts compromise the advantages of coronary stenting. The objective of this randomized, multicenter study was to assess whether a reduced strut thickness of coronary stents is associated with improved follow-up angiographic and clinical results. METHODS AND RESULTS: A total of 651 patients with coronary lesions situated in native vessels >2.8 mm in diameter were randomly assigned to receive 1 of 2 commercially available stents of comparable design but different thickness: 326 patients to the thin-strut stent (strut thickness of 50 microm) and 325 patients to the thick-strut stent (strut thickness of 140 microm). The primary end point was the angiographic restenosis (>/=50% diameter stenosis at follow-up angiography). Secondary end points were the incidence of reinterventions due to restenosis-induced ischemia and the combined rate of death and myocardial infarctions at 1 year. The incidence of angiographic restenosis was 15.0% in the thin-strut group and 25.8% in the thick-strut group (relative risk, 0.58; 95% CI, 0.39 to 0.87; P=0.003). Clinical restenosis was also significantly reduced, with a reintervention rate of 8.6% among thin-strut patients and 13.8% among thick-strut patients (relative risk, 0.62; 95% CI, 0.39 to 0.99; P=0.03). No difference was observed in the combined 1-year rate of death and myocardial infarction. CONCLUSIONS: The use of a thinner-strut device is associated with a significant reduction of angiographic and clinical restenosis after coronary artery stenting. These findings may have relevant implications for the currently most widely used percutaneous coronary intervention.

Effect of glycoprotein IIb/IIIa receptor blockade with abciximab on clinical and angiographic restenosis rate after the placement of coronary stents following acute myocardial infarction.

OBJECTIVES: In the Intracoronary Stenting and Antithrombotic Regimen-2 trial (ISAR-2), we sought to investigate the effect of abciximab on angiographic and clinical restenosis after stenting following acute myocardial infarction (AMI). We also intended to assess the impact of abciximab on clinical outcome in this setting. BACKGROUND: It is unclear whether abciximab reduces neointima formation after stenting. Such an effect may be particularly prominent in thrombus-containing lesions. METHODS: Patients undergoing stenting within 48 h after onset of AMI were randomly assigned to receive either standard-dose heparin or abciximab plus reduced-dose heparin. Of 401 patients randomized, 366 without 30-day adverse events were eligible for six-month angiographic follow-up. Scheduled angiography was performed in 80% of these patients. RESULTS: By 30 days, the composite clinical end point of death, reinfarction, and target lesion revascularization (TLR) was reached in 5.0% of the abciximab group and in 10.5% of the control group (p = 0.038). At one year, absolute reduction in the composite clinical end point by abciximab was still 5.7% but had lost its statistical significance. Our primary end point, late lumen loss, was 1.26+/-0.85 mm with abciximab and 1.21+/-0.74 mm with standard heparin (p = 0.61), and binary angiographic restenosis rates were 31.1% and 30.6%, respectively (p = 0.92). CONCLUSIONS: In patients undergoing stenting following AMI, abciximab exerted beneficial effects by substantially reducing the 30-day rate of major adverse cardiac events. During one-year follow-up, there was no additional benefit from a reduction in TLR nor did abciximab reduce angiographic restenosis.

[Reduced radioiodine uptake at increased iodine intake and 131I-induced release of "cold" iodine stored in the thyroid]. / Verminderter Radioiod-Uptake durch erhöhte Iodzufuhr und 131I-induzierte Freisetzung von thyreoidal gespeichertem "kalten" Iod.

AIM: The extent of urinary iodine excretion (UIE) provides information about iodine supply and release. In the present study we investigated correlations between UIE and radioiodine uptake (RIU) as well as effects of radioiodine therapy on UIE in patients with autonomous goitre. PATIENTS, METHODS: In 197 consecutive patients with thyroid autonomy, UIE was measured twice during radioiodine test (RITe) and correlated with RIU. In 98 of these patients, thyroglobulin and thyroid volume (V) were determined prior to therapy. Individual changes in urinary iodine excretion (DeltaUIE) and TG (DeltaTG) could be investigated four weeks (4W) and six months (6M) after radioiodine therapy. Additionally, DeltaV was determined 6M after therapy. DeltaUIE, DeltaTG and DeltaV were correlated with target dose and target volume. RESULTS: Patients with higher iodine excretion exhibited significantly lower thyroidal radioiodine uptake values. Twofold increased UIE prior to therapy decreased radioiodine uptake by 25%. Compared with pretherapeutic values, UIE and TG were significantly increased four weeks after radioiodine therapy (p < 0.001). Median values of both parameters were found to be doubled. The product of target dose and target volume was not only correlated with a decrease of thyroid volume 6M after therapy, but also with an increase of UIE and TG in the early phase after therapy. CONCLUSIONS: It was confirmed that UIE during RITe is a measure for iodine intake and can be used to investigate the competition between stable iodine and radioiodine. The increase of UIE and TG four weeks after therapeutic administration of radioiodine can be explained by disintegrated thyroid follicles. The therapy-induced iodine release may be one important cause for the development of hyperthyroidism in some patients during the first weeks after radioiodine therapy. It may contribute to the known decrease of radioiodine uptake after preapplications of 131I in various thyroid diseases.

Feasibility and accuracy of 64-row MDCT coronary imaging from a centre with early experience: a review and comparison with established centres.

The accuracy of multi-detector computed tomographic (MDCI) coronary angiography (CTA) is dependant on image quality as well as the experience of the operator. Established centers have reported negative predictive values of over 95%. The aim of our study was to investigate the accuracy and feasibility of CTA for the assessment of haemodynamically significant coronary stenosis in a center with very early experience (<6 months) utilizing the improved spatial and temporal resolutions of the latest generation 64-row MDCI scanner. One hundred and twenty eight patients (93 male, 35 female; mean age 56.2 +/- 9.5 years) with suspected or known coronary artery disease underwent both CIA and conventional coronary angiographv (CCA). The sensitivity, specificity, positive (PPV) and negative (NPV) predictive values for stenoses > or =50% by CIA compared to CCA were 70%, 97%, 70% and 97% respectively. Evaluation of main and proximal segments in patients with good quality images (78% of patients) produced values of 94%, 95%, 74% and 99% respectively. The improved spatial and temporal resolutions of 64-row MJ) CT provided a high negative predictive value in assessing significant coronary artery stenosis even in a centre with very early experience. However, new centers embarking on CTA might not be able to reproduce the results reported by more experienced centers.

Characterization and inhibition of beta-adrenergic receptor kinase in intact myocytes.

OBJECTIVES: beta-Adrenergic receptor kinase (beta ARK) phosphorylates and thereby inactivates agonist-occupied beta-adrenergic receptors (beta AR). beta ARK is thought to play an important role in the regulation of cardiac function. Therefore, we studied beta ARK activation and its inhibition in intact smooth muscle cells and in cardiomyoblasts. METHODS AND RESULTS: beta AR agonist-stimulated translocation of beta ARK was monitored by immunofluorescence labelling with specific antibodies and confocal laser scanning microscopy in DDT-MF 2 hamster smooth muscle cells and in H9c2 rat cardiomyoblasts. In unstimulated cells. beta ARK was mainly located in the cytosol. After beta AR agonist stimulation, the beta ARK signal was partially translocated to the membranes. Liposomal gene transfer of the COOH-terminus of beta ARK ('beta ARKmini') as a beta ARK inhibitor led to functional expression of this protein in both cell lines with high efficiency. Western blots with beta ARK antibodies showed a gene concentration-dependent immunoreactivity of the 'beta ARKmini' protein. 'beta ARKmini'-transfected myocytes demonstrated reduced membrane targeting of the beta ARK immuno-fluorescence signal. Additionally, the effect of 'beta ARKmini' on beta AR-induced desensitization of myocytic cAMP accumulation was investigated. In control cells, desensitization with isoproterenol led to a subsequent reduction of beta AR-induced cAMP accumulation. In 'beta ARKmini'-transfected myocytes, this beta AR-induced desensitization was significantly diminished, whereas normal beta AR-induced cAMP accumulation was unaffected. A gene concentration of 2 micrograms 'beta ARKmini' DNA/100,000 cardiomyoblasts, and of 0.7 microgram 'beta ARKmini' DNA/100,000 DDT-MF2 smooth muscle cells led to approximately 5.9- and approximately 5.6-fold overexpressions of 'beta ARKmini' vs. native beta ARK, respectively. These gene doses proved sufficient to attenuate beta-adrenergic desensitization significantly. CONCLUSIONS: (1) beta ARK translocation was evidenced in DDT-MF2 smooth muscle cells and in cardiomyoblasts by confocal laser scanning microscopy. (2) Feasibility of 'beta ARKmini' gene transfer to myocytes was demonstrated, and necessary gene doses for beta ARK inhibition were titered. (3) Overexpression of 'beta ARKmini' functionally interacted with endogenous beta-adrenergic signal transduction, leading to sustained cAMP accumulation after prolonged beta-adrenergic stimulation.

Adenosine inhibits norepinephrine release in the postischemic rat heart: the mechanism of neuronal stunning.

OBJECTIVE: Numerous studies support the concept of impaired postischemic sympathetic neurotransmission in the heart. We hypothesized that postischemic neuronal dysfunction (neuronal stunning) is caused by a transient suppression of exocytotic norepinephrine (NE) release from sympathetic nerve terminals. Furthermore, we assessed the role of presynaptic adenosine-receptors and alpha2-adrenoceptors in neuronal stunning. METHODS AND RESULTS: Exocytotic NE release was induced by two electrical field stimulations (S(1) and S(2)) in isolated perfused rat hearts. S(1) was performed under baseline conditions and S(2) either during or following intervention. Results are expressed as mean S(2)/S(1) ratios+/-S.E.M. Stepwise increase of global ischemic periods (10, 20, and 30 min) induced a progressive suppression of NE release in the postischemic hearts, which was reversible during reperfusion. Both the degree and duration of NE suppression was dependent on the extent of the preceding ischemic period. Following 10-min ischemia complete recovery of NE release was achieved after 5-min reperfusion (1.07+/-0.12), whereas 5-min reperfusion did not restore NE release after 30 min (0.36+/-0.07) of ischemia. The adenosine-receptor antagonists 8-phenyltheophylline (8-PT; non-selective) and 8-cyclopentyl-1,3-dipropylxanthine (DPCPX; adenosine A1-receptor subtype selective) significantly increased NE release after 30-min ischemia and 5-min reperfusion (0.78+/-0.06 and 0.64+/-0.07), while in the same experimental protocol blockade of alpha2-adrenoceptors by yohimbine failed to restore the postischemic release (0.24+/-0.06). In non-ischemic hearts the adenosine analogue R(-)N(6)-(2-phenylisopropyl)adenosine (R-PIA) resulted in a marked suppression of NE release (0.61+/-0.07). The inhibitory effect of R-PIA and 2-chloro-N(6)-cyclopentyladenosine (CCPA; adenosine A1-receptor subtype selective agonist) persisted 5 min after cessation of R-PIA (0.62+/-0.05) and CCPA (0.58+/-0.04). Activation of alpha2-adrenoceptors by 5-bromo-N-(4,5-dihydro-1H-imidazol-2-yl)-6-quinoxalinamine (UK 14,304) also caused a reduction of NE release (0.50+/-0.02), but the release increased to control levels 5 min after cessation of UK 14,304 (0.90+/-0.06). CONCLUSIONS: The results establish the phenomenon of neuronal stunning in terms of a postischemic suppression of exocytotic NE release and provide evidence that neuronal stunning is mediated by endogenous adenosine through activation of presynaptic adenosine A1-receptors.

Blocking caspase-activated apoptosis improves contractility in failing myocardium.

Cardiac myocyte apoptosis has been demonstrated in end-stage failing human hearts. The therapeutic utility of blocking apoptosis in congestive heart failure (CHF) has not been elucidated. This study investigated the role of caspase activation in cardiac contractility and sarcomere organization in the development of CHF. In a rabbit model of heart failure obtained by rapid ventricular pacing, we demonstrate, using in vivo transcoronary adenovirus-mediated gene delivery of the potent caspase inhibitor p35, that caspase activation is associated with a reduction in contractile force of failing myocytes by destroying sarcomeric structure. In this animal model gene transfer of p35 prevented the rise in caspase 3 activity and DNA-histone formation. Genetically manipulated hearts expressing p35 had a significant improvement in left ventricular pressure rise (+dp/dt), decreased end-diastolic chamber pressure (LVEDP), and the development of heart failure was delayed. To better understand this benefit, we examined the effects of caspase 3 on cardiomyocyte dysfunction in vitro. Microinjection of activated caspase 3 into the cytoplasm of intact myocytes induced sarcomeric disorganization and reduced contractility of the cells. These results demonstrate a direct impact of caspases on cardiac function and may lead to novel therapeutic strategies via antiapoptotic regimens.

G protein beta3 subunit polymorphism and risk of thrombosis and restenosis following coronary stent placement.

C825T polymorphism in the G protein beta3 subunit gene (GNB3) has been associated with arterial hypertension, coronary artery disease and myocardial infarction. On the cellular level, C825T polymorphism is associated with altered transmembrane signaling via adenylyl cyclase inhibiting (G(i)) G proteins. This study was designed to test whether C825T polymorphism has an impact on the processes leading to restenosis and thrombosis following coronary stenting. The primary endpoint of the study was angiographic restenosis (> or =50% diameter stenosis) at 6-month follow-up. Secondary endpoint was angiographically proven stent thrombosis within 30 days of implantation. In the 562 consecutive patients C825T genotype was CC, 46.1%, CT, 45.2% and TT, 8.7%. The incidence of angiographic restenosis was 32.7% in homozygous carriers of the C allele, 28.2% in CT patients and 33.3% in homozygous carriers of the T allele (P = 0.563). C825T genotype distribution in 34 consecutive patients with subacute stent thrombosis (44.0% CC, 50.0% CT, and 6.0% TT) was not different from that of 451 patients with angiographically patent stented vessel (45.4% CC, 44.6% CT, 10.0% TT; P = 0.644). In conclusion, C825T polymorphism has no appreciable impact on the mechanisms leading to thrombosis and restenosis following coronary stent placement.

Expression and kinetics of cytokines determined by intracellular staining using flow cytometry.

Cytokine production by human lymphocytes was assessed by a flow cytometric procedure involving staining of intracellular cytokines by the paraformaldehyde-saponin procedure. The production of interleukin 2 (IL2), interferon gamma (IFNgamma) and tumor necrosis factor alpha (TNFalpha) was determined in T-helper (Th) and cytotoxic T-cells (CTL) as well as in naive and memory cells after stimulation with phorbol-12-myristate-13-acetate (PMA) and ionomycin under the influence of monensin. Kinetic studies on IL2, IFNgamma and TNFalpha in lymphocyte subpopulations showed that TNFalpha was the first cytokine produced by T-cells. Production of this cytokine peaked at 2 h and declined rapidly thereafter. The peak of IL2 and IFNgamma production was at 8 h, and production of IL2 exceeded that of IFNgamma in T-cells at all times. IL2 production declined markedly after 8 h, while IFNgamma remained relatively stable for 24 h. IL2 and TNFalpha were mainly produced by Th cells while CTL primarily expressed IFNgamma. At all times a higher percentage of memory cells stained cytokine positive compared to naive cells and production of cytokines increased more rapidly in the memory cells. Naive cells produced primarily IL2, while memory cells expressed all the studied cytokines in substantial amounts. Kinetic studies between 1 and 24 h showed that 5 h was the optimal time point for evaluating the cytokines studied; hence normal values obtained from 50 healthy blood donors were evaluated after 5 h continuous PMA and ionomycin stimulation.

Comparison of effects of clopidogrel versus ticlopidine on platelet function in patients undergoing coronary stent placement.

Clopidogrel in combination with aspirin administered as a loading dose of 450 mg reveals an accelerated antiplatelet effect in the early hours after first administration in patients undergoing coronary stent placement.

Sodium-hydrogen exchange inhibition: novel strategy to prevent myocardial injury following ischemia and reperfusion.

Activation of Na+/H+ exchange and subsequent calcium overload in cardiac myocytes appear to play an important role in myocardial tissue injury following ischemia and reperfusion. Results of several in vitro studies in isolated myocytes and heart preparations and in vivo studies in pigs and rats have suggested that inhibition of Na+/H+ exchange is an effective means to prevent lethal reperfusion injury, arrhythmia, and improve myocardial contractile dysfunction. In patients with acute myocardial infarction (MI), any preventive agent is administered immediately before or shortly after reperfusion, rather than before the occurrence of coronary occlusion. The direct interventional approach to treating acute MI provides the opportunity to see if reperfusion has already occurred; if not, a protective agent prior to mechanical reperfusion by percutaneous transluminal coronary angioplasty (PTCA) can be administered to limit reperfusion injury. In a multicenter, randomized, placebo-controlled clinical trial, we tested the hypothesis that inhibition of Na+/H+ exchange with cariporide (HOE 642) could limit infarct size and improve myocardial function in patients with acute transmural MI treated with direct PTCA. Patients were randomized to receive placebo or cariporide given as a 40-mg intravenous bolus prior to reperfusion. Global and regional left ventricular function were analyzed via paired contrast left ventriculograms performed before direct PTCA and after 21 days. Myocardial enzymes (i.e., creatine kinase [CK], CK-MB, and lactate dehydrogenase) as markers for myocardial tissue injury were evaluated as well. The results of this pilot study suggested that the Na+/H+ exchange inhibition could be of benefit to prevent reperfusion injury in patients with acute anterior MI treated with direct angioplasty.