Mean platelet volume as a predictor of cardiovascular risk: a systematic review and meta-analysis

AIM

To determine whether an association exists between mean platelet volume (MPV) and acute myocardial infarction (AMI) and other cardiovascular events. Platelet activity is a major culprit in atherothrombotic events. MPV, which is widely available in clinical practice, is a potentially useful biomarker of platelet activity in the setting of cardiovascular disease.

METHODS AND RESULTS

We performed a systematic review and meta-analysis investigating the association between MPV and AMI, all-cause mortality following myocardial infarction, and restenosis following coronary angioplasty. Results were pooled using random-effects modeling. Pooled results from 16 cross-sectional studies involving 2809 patients investigating the association of MPV and AMI indicated that MPV was significantly higher in those with AMI than those without AMI [mean difference 0.92 fL, 95% confidence interval (CI) 0.67-1.16, P < 0.001). In subgroup analyses, significant differences in MPV existed between subjects with AMI, subjects with stable coronary disease (P < 0.001), and stable controls (P < 0.001), but not vs. those with unstable angina (P = 0.24). Pooled results from three cohort studies involving 3184 patients evaluating the risk of death following AMI demonstrated that an elevated MPV increased the odds of death as compared with a normal MPV (11.5% vs. 7.1%, odds ratio 1.65, 95% CI 1.12-2.52, P = 0.012). Pooled results from five cohort studies involving 430 patients who underwent coronary angioplasty revealed that MPV was significantly higher in patients who developed restenosis than in those who did not develop restenosis (mean difference 0.98 fL, 95% CI 0.74-1.21, P < 0.001).

CONCLUSIONS

Elevated MPV is associated with AMI, mortality following myocardial infarction, and restenosis following coronary angioplasty. These data suggest that MPV is a potentially useful prognostic biomarker in patients with cardiovascular disease. Whether the relationship is causal, and whether MPV should influence practice or guide therapy, remains unknown.

The International Personality Disorder Examination. The World Health Organization/Alcohol, Drug Abuse, and Mental Health Administration international pilot study of personality disorders

BACKGROUND

One of the aims of the World Health Organization/Alcohol, Drug Abuse, and Mental Health Administration joint program on psychiatric diagnosis and classification is the development and standardization of diagnostic assessment instruments for use in clinical research worldwide. The International Personality Disorder Examination (IPDE) is a semistructured clinical interview compatible with the International Classification of Diseases, Tenth Revision, and the DMS-III-R classification systems. This is the first report of the results of a field trial to investigate the feasibility of using the IPDE to assess personality disorders worldwide.

METHODS

The IPDE was administered by 58 psychiatrists and clinical psychologists to 716 patients enrolled in clinical facilities at 14 participating centers in 11 countries in North America, Europe, Africa, and Asia. To determine interrater reliability, 141 of the IPDEs (20%) were independently rated by a silent observer. To determine temporal stability, 243 patients (34%) were reexamined after an average interval of 6 months.

RESULTS

The IPDE proved acceptable to clinicians and demonstrated an interrater reliability and temporal stability roughly similar to instruments used to diagnose the psychoses, mood, anxiety, and substance use disorders.

CONCLUSION

It is possible to assess personality disorders with reasonably good reliability in different nations, languages, and cultures using a semistructured clinical interview that experienced clinicians find relevant, meaningful, and user-friendly.

Relationship between delay in performing direct coronary angioplasty and early clinical outcome in patients with acute myocardial infarction: results from the global use of strategies to open occluded arteries in Acute Coronary Syndromes (GUSTO-IIb) trial

BACKGROUND

Time to treatment with thrombolytic therapy is a critical determinant of mortality in acute myocardial infarction. Little is known about the relationship between the time to treatment with direct coronary angioplasty and clinical outcome. The objectives of this study were to determine both the time required to perform direct coronary angioplasty in the Global Use of Strategies to Open Occluded Arteries in Acute Coronary Syndromes (GUSTO-IIb) trial and its relationship to clinical outcome.

METHODS AND RESULTS

Patients randomized to direct coronary angioplasty (n=565) were divided into groups based on the time between study enrollment and first balloon inflation. Patients randomized to angioplasty who did not undergo the procedure were also analyzed. The median time from study enrollment to first balloon inflation was 76 minutes; 19% of patients assigned to angioplasty did not undergo an angioplasty procedure. The 30-day mortality rate of patients who underwent balloon inflation </=60 minutes after study enrollment was 1.0%; 61 to 75 minutes after enrollment, 3.7%; 76 to 90 minutes after enrollment, 4.0%; and >/=91 minutes after enrollment, 6.4%. The mortality rate of patients assigned to angioplasty who never underwent the procedure was 14.1% (P=0.001). Logistic regression analysis revealed that the time from enrollment to first balloon inflation was a significant predictor of mortality within 30 days; after adjustment for differences in baseline characteristics, the odds of death increased 1.6 times (P=0.008) for a movement from each time interval to the next.

CONCLUSIONS

The time to treatment with direct PTCA, as with thrombolytic therapy, is a critical determinant of mortality.

Point-of-care measured platelet inhibition correlates with a reduced risk of an adverse cardiac event after percutaneous coronary intervention: results of the GOLD (AU-Assessing Ultegra) multicenter study

BACKGROUND

The optimal level of platelet inhibition with a glycoprotein (GP) IIb/IIIa antagonist necessary to minimize thrombotic complications in patients undergoing a percutaneous coronary intervention (PCI) is currently unknown.

METHODS AND RESULTS

Five hundred patients undergoing a PCI with the planned use of a GP IIb/IIIa inhibitor had platelet inhibition measured at 10 minutes, 1 hour, 8 hours, and 24 hours after the initiation of therapy with the Ultegra Rapid Platelet Function Assay (Accumetrics). Major adverse cardiac events (MACES: composite of death, myocardial infarction, and urgent target vessel revascularization) were prospectively monitored, and the incidence correlated with the measured level of platelet function inhibition at all time points. One quarter of all patients did not achieve >/=95% inhibition 10 minutes after the bolus and experienced a significantly higher incidence of MACEs (14.4% versus 6.4%, P=0.006). Patients whose platelet function was <70% inhibited at 8 hours after the start of therapy had a MACE rate of 25% versus 8.1% for those >/=70% inhibited (P=0.009). By multivariate analysis, platelet function inhibition >/=95% at 10 minutes after the start of therapy was associated with a significant decrease in the incidence of a MACE (odds ratio 0.46, 95% CI 0.22 to 0.96, P=0.04).

CONCLUSIONS

Substantial variability in the level of platelet function inhibition is achieved with GP IIb/IIIa antagonist therapy among patients undergoing PCI. The level of platelet function inhibition as measured by a point-of-care assay is an independent predictor for the risk of MACEs after PCI.

Contemporary reperfusion therapy for cardiogenic shock: the GUSTO-I trial experience. The GUSTO-I Investigators. Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries

OBJECTIVES

This study sought to examine the incidence, temporal profile and clinical implications of shock in a large trial of thrombolytic therapy for acute myocardial infarction.

BACKGROUND

Despite advances in the treatment of acute ischemic syndromes, cardiogenic shock remains associated with significant morbidity and mortality.

METHODS

Patients who presented within 6 h of symptom onset were randomized to four treatment strategies: 1) streptokinase plus subcutaneous heparin; 2) streptokinase plus intravenous heparin; 3) accelerated recombinant tissue-type plasminogen activator (rt-PA) plus intravenous heparin; or 4) streptokinase and rt-PA plus intravenous heparin. The primary end point was 30-day all-cause mortality.

RESULTS

Shock occurred in 2,972 patients (7.2%): 315 (11%) had shock on arrival, and 2,657 (89%) developed shock after hospital admission. Reinfarction occurred in 11% of patients who developed shock compared with 3% of patients without shock. The mortality rate was significantly higher in patients who presented with (57%) or developed (55%) shock than in those without shock (3%) (p < 0.001). Shock developed significantly less frequently in patients receiving rt-PA. There were fewer deaths in patients who presented with shock and were treated with streptokinase plus intravenous heparin or who developed shock and were treated with streptokinase plus subcutaneous heparin. Patients who developed shock had a significantly lower 30-day mortality rate if angioplasty was performed.

CONCLUSIONS

Because cardiogenic shock occurred most often after admission and with recurrent ischemia and reinfarction, recognizing signs of incipient shock may improve outcome. Fewer patients treated with rt-PA developed shock, yet those developing shock had the same high mortality rate as those presenting with shock, regardless of treatment. Only angioplasty was associated with a significantly lower mortality rate.

Immediate and long-term outcome of intracoronary stent implantation for true bifurcation lesions

OBJECTIVES

The aim of this study was to evaluate the immediate and long-term outcome of intracoronary stent implantation for the treatment of coronary artery bifurcation lesions.

BACKGROUND

Balloon angioplasty of true coronary bifurcation lesions is associated with a lower success and higher complication rate than most other lesion types.

METHODS

We treated 131 patients with bifurcation lesions with > or =1 stent. Patients were divided into two groups; Group (Gp) 1 included 77 patients treated with a stent in one branch and percutaneous transluminal coronary angioplasty (PTCA) (with or without atherectomy) in the side branch, and Gp 2 included 54 patients who underwent stent deployment in both branches. The Gp 2 patients were subsequently divided into two subgroups depending on the technique of stent deployment. The Gp 2a included 19 patients who underwent Y-stenting, and Gp 2b included 33 patients who underwent T-stenting.

RESULTS

There were no significant differences between the groups in terms of age, gender, frequency of prior myocardial infarction (MI) or coronary artery bypass grafting (CABG), or vessels treated. Procedural success rates were excellent (89.5 to 97.4%). After one-year follow-up, no significant differences were seen in the frequency of major adverse events (death, MI, or repeat revascularization) between Gp 1 and Gp 2. Adverse cardiac events were higher with Y-stenting compared with T-stenting (86.3% vs. 30.4%, p = 0.004).

CONCLUSIONS

Stenting of bifurcation lesions can be achieved with a high success rate. However, stenting of both branches offers no advantage over stenting one branch and performing balloon angioplasty of the other branch.

Outcomes of patients with chronic renal insufficiency in the bypass angioplasty revascularization investigation

BACKGROUND

Although severe chronic kidney disease (CKD) is an independent predictor of mortality among patients with coronary artery disease, the impact of mild CKD on morbidity and mortality has not been fully defined.

METHODS AND RESULTS

Morbidity and mortality for the 3608 patients with multivessel coronary artery disease enrolled in the Bypass Angioplasty Revascularization Investigation randomized trial and registry were compared on the basis of the presence and absence of CKD, defined as a preprocedure serum creatinine level of >1.5 mg/dL. Seventy-six patients had CKD. Patients with renal insufficiency were older and more likely to have a history of diabetes, hypertension, and other comorbidities. Among patients undergoing PTCA, patients with CKD had a greater frequency of in-hospital death and cardiogenic shock (P<0.05 and 0.01, respectively). There was a trend toward a larger proportion of patients with CKD experiencing angina at 5 years (P=0.079). Patients with CKD had more cardiac admissions (P=0.003 and <0.0001 for patients undergoing PTCA and CABG, respectively) and a shorter time to subsequent CABG after initial revascularization than patients without CKD (P=0.01). CKD was associated with a higher risk of death at 7 years, both of all causes (relative risk 2.2, P<0.001) and of cardiac causes (relative risk 2.8, P<0.001).

CONCLUSIONS

CKD is associated with an increased risk of recurrent hospitalization, subsequent CABG, and mortality. This increased risk of death is independent of and additive to the risk associated with diabetes.

Initial and long-term outcome of 354 patients after coronary balloon angioplasty of total coronary artery occlusions

BACKGROUND

Coronary balloon angioplasty of chronic total occlusions is associated with relatively low success rates and a high incidence of restenosis. Whether there is long-term benefit in performing angioplasty of these lesions is unknown. The purpose of the present report was to analyze the long-term outcome of a large series of patients undergoing this procedure.

METHODS AND RESULTS

A computerized database analysis of 354 consecutive patients (from 1979 to 1990) who underwent coronary angioplasty of a chronic total coronary occlusion was performed (mean age, 62.3 years). Initial technical success was achieved in 69%; in 66%, success was achieved without procedural death or need for coronary artery surgery. During hospitalization, six patients suffered myocardial infarction, nine required emergency bypass surgery, and nine patients died. During a mean follow-up period of 2.7 years, no difference was found in survival or freedom from myocardial infarction among 234 successfully dilated patients compared with 120 patients with a failed attempt. However, the use of coronary artery bypass surgery was significantly less after successful dilation (p less than 0.0001 versus failed attempt). No significant difference in the cumulative incidence of severe angina was observed between these two patient populations, with the majority remaining asymptomatic. Restenosis occurred in 59% of 69 patients who returned for follow-up angiography.

CONCLUSIONS

Successful recanalization is achieved in the majority of patients undergoing angioplasty of chronic total occlusions and reduces the need for coronary artery bypass surgery. However, no major impact on either survival or incidence of myocardial infarction was noted after successful recanalization when patients with surgery were included.

Impact of an aggressive invasive catheterization and revascularization strategy on mortality in patients with cardiogenic shock in the Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries (GUSTO-I) trial. An observational study

BACKGROUND

Although retrospective analyses have revealed an association between survival and coronary angiography and angioplasty in patients with acute myocardial infarction complicated by cardiogenic shock, the degree to which bias in the selection of patients to undergo these procedures contributes to this observation remains unclear.

METHODS AND RESULTS

We studied 2200 patients in the Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries (GUSTO-I) trial with acute myocardial infarction complicated by cardiogenic shock (systolic blood pressure < 90 mm Hg for > or = 1 hour) who survived > or = 1 hour after the onset of shock to determine the influence of an aggressive strategy of early angiography (within 24 hours of shock onset) and coronary angioplasty or bypass surgery, if appropriate, on survival. Revascularization was not protocol mandated but was selected by the attending physicians. Shock was present on admission in 11% and developed after admission in 89% of shock patients. The 30-day mortality was 38% in the 406 patients who underwent early angiography and were referred within 24 hours for angioplasty (n = 175), bypass surgery (n = 36), angioplasty and bypass surgery (n = 22), or neither (late or no revascularization, n = 173) compared with 62% in the 1794 patients who did not (P = .0001). However, there were important differences in the baseline characteristics of the two groups, including younger age (63 versus 68 years, P = .0001), less prior infarction (19% versus 27%, P = .001), and a shorter time to thrombolytic therapy (2.9 versus 3.2 hours, P = .0001) in patients treated with an aggressive strategy. Using multivariate logistic regression analysis to adjust for differences in baseline characteristics, an aggressive strategy was independently associated with reduced 30-day mortality (odds ratio, 0.43 [confidence interval, 0.34 to 0.54], P = .0001).

CONCLUSIONS

An aggressive strategy of early angiography (and revascularization when appropriate) is associated with a reduction in mortality in patients with acute myocardial infarction and cardiogenic shock who receive thrombolytic therapy.

Characterization of sodium-dependent [3H]GBR-12935 binding in brain: a radioligand for selective labelling of the dopamine transport complex

High-affinity and saturable binding sites for the diphenyl-substituted piperazine derivative [3H]GBR-12935 have been characterized in crude synaptosomal membranes prepared from rat brain. The specific binding of [3H]GBR-12935 is sodium-dependent and is unevenly distributed among various brain regions, with the highest concentration of binding sites being found in the corpus striatum and nucleus accumbens. Sodium-dependent [3H]GBR-12935 binding in all other brain areas was 10% or less of the binding found in the striatum. The affinity of [3H]GBR-12935 for binding sites in the striatum is increased in the presence of Na+ but other cations, including K+, Ca2+, or Mg2+, inhibit specific binding. There is an excellent correlation (r = 0.96, p less than 0.01) between the potencies of a series of drugs in inhibiting [3H]GBR-12935 binding to striatal membranes and their potencies in inhibiting [3H]3,4-dihydroxyphenylethylamine ([3H]dopamine) uptake in synaptosomes. Agonists and antagonists of other neurotransmitter receptor or drug recognition sites have little or no effect on specific [3H]GBR-12935 binding to striatal membranes. In addition, prior intracerebroventricular administration of 6-hydroxydopamine results in a decrease in the number of specific [3H]GBR-12935 binding sites in the striatum. These data indicate that [3H]GBR-12935 is a selective radioligand of the presynaptic dopamine transport complex in brain.

Coronary artery stents

CONTEXT

Intracoronary stents are now used for the majority of patients undergoing percutaneous coronary revascularization, and the body of scientific knowledge about stents has expanded rapidly in the last several years.

OBJECTIVE

To review the evidence supporting the widespread use of intracoronary stents.

DATA SOURCES

The MEDLINE database was searched for articles from 1990 through January 2000 using the indexing terms stents, coronary artery disease, and angioplasty. Additional data sources included bibliographies of articles identified on MEDLINE, bibliographies in textbooks on percutaneous coronary interventions, and preliminary data presented at recent national and international cardiology conferences.

STUDY SELECTION

We selected for review studies that assessed the effects of stenting on the immediate and long-term outcome of patients undergoing percutaneous coronary revascularization. If data from randomized controlled trials were not available for specific patient subsets or lesion characteristics, observational studies were included.

DATA EXTRACTION

The methodologic characteristics of studies in coronary stenting were extracted and summarized according to key components of research design, including lesion type, location, and adjunctive therapy used. Studies were classified according to the strength of the available data into proven and unproven indications for stent use.

DATA SYNTHESIS

Coronary artery stents increase the safety of interventional procedures, increase procedure success rates, and decrease the need for emergency coronary artery bypass graft surgery.

CONCLUSIONS

Intracoronary stents have become an essential component of the catheter-based treatment of coronary artery disease. The evidence indicates that elective stenting, rather than provisional stenting or balloon angioplasty alone, improves clinical outcomes in the months following percutaneous coronary revascularization in a wide variety of clinical settings and lesion types. JAMA. 2000;284:1828-1836.

The effect of estrogen replacement therapy on plasma nitric oxide and endothelin-1 levels in postmenopausal women

BACKGROUND

Estrogen replacement therapy (ERT) in postmenopausal women decreases cardiac mortality and improves endothelial function. The endothelium regulates vascular tone and growth by releasing such factors as nitric oxide and endothelin-1.

OBJECTIVE

To determine whether ERT alters the balance between the total oxidized products of nitric oxide and endothelin-1.

DESIGN

Single-arm, before-after clinical trial.

SETTING

Outpatient clinical research center of an academic medical center.

PATIENTS

15 postmenopausal women.

INTERVENTION

Treatment with 17 beta-estradiol for 6 months and a 10-day course of methoxyprogesterone every 3 months.

MEASUREMENTS

Plasma nitric oxide and endothelin-1 levels were measured at baseline and after 6 months of ERT.

RESULTS

The mean baseline nitric oxide level was 27.5 nmol/mL (range, 20.3 to 34.8 nmol/mL) and increased by a mean of 7.2 nmol/mL (range, 0.2 to 14.1 nmol/mL) (P = 0.04). The mean baseline plasma endothelin-1 level was 16.4 pg/mL (range, 12.0 to 20.8 pg/mL) and decreased by a mean of 3.9 pg/mL (range, 0.4 to 7.8 pg/mL) (P = 0.04). The mean baseline ratio of nitric oxide to endothelin-1 was 2.0 (range, 1.3 to 2.8) and increased by 1.2 (range, 0.1 to 2.2) (P = 0.03).

CONCLUSION

ERT results in an increased ratio of nitric oxide to endothelin-1. This may be one mechanism by which ERT provides cardiovascular benefit.

Systematic 16S rRNA gene sequencing of atypical clinical isolates identified 27 new bacterial species associated with humans

Clinical microorganisms isolated during a 5-year study in our hospital that could not be identified by conventional criteria were studied by 16S rRNA gene sequence analysis. Each isolate yielded a > or =1,400-bp sequence containing <5 ambiguities which was compared with the GenBank 16S rRNA gene library; 1,404 such isolates were tested, and 120 were considered unique (27 isolates) or rare (< or =10 cases reported in the literature) human pathogens. Eleven new species, "Actinobaculum massiliae," "Candidatus Actinobaculum timonae," Paenibacillus sanguinis, "Candidatus Bacteroides massiliae," Chryseobacterium massiliae, "Candidatus Chryseobacterium timonae," Paenibacillus massiliensis, "Candidatus Peptostreptococcus massiliae," "Candidatus Prevotella massiliensis," Rhodobacter massiliensis, and "Candidatus Veillonella atypica" were identified. Sixteen species were obtained from humans for the first time. Our results show the important role that 16S rRNA gene sequence-based bacterial identification currently plays in recognizing unusual and emerging bacterial diseases.

Cardiogenic shock in patients with acute ischemic syndromes with and without ST-segment elevation

BACKGROUND

Cardiogenic shock is usually considered a sequela of ST-segment elevation myocardial infarction. There are limited prospective data on the incidence and significance of shock in non-ST-segment elevation patients. This study assessed the incidence and outcomes of cardiogenic shock developing after enrollment among patients with and without ST-segment elevation in the Global Use of Strategies To Open Occluded Coronary Arteries (GUSTO)-IIb trial.

METHODS AND RESULTS

Among 12,084 patients in GUSTO-IIb who did not present with cardiogenic shock, 4092 (34%) had and 7991 (66%) did not have ST-segment elevation on the enrollment ECG. Cardiogenic shock developed in 4.2% of ST-segment elevation patients compared with 2.5% of patients without ST-segment elevation (odds ratio, 0. 581; 95% CI, 0.472 to 0.715; P<0.001). Shock developed significantly later among patients without ST-segment elevation. There were significant differences in baseline characteristics between shock patients with and without ST-segment elevation: Patients without ST-segment elevation were older, more frequently had diabetes mellitus and 3-vessel disease, but had less TIMI grade 0 flow at angiography. Regardless of the initial ECG, mortality was high: 63% among patients with ST-segment elevation and 73% in those without ST-segment elevation.

CONCLUSIONS

Cardiogenic shock occurs in the setting of acute ischemic syndromes regardless of whether ST-segment elevation is present. The incidence, patient characteristics, timing, clinical course, and angiographic findings differ between the 2 groups. Mortality from cardiogenic shock is similarly high among patients with and without ST-segment elevation.

Long-term clinical outcome in the Bypass Angioplasty Revascularization Investigation Registry: comparison with the randomized trial. BARI Investigators

BACKGROUND

The Bypass Angioplasty Revascularization Investigation (BARI) included 4039 patients with multivessel coronary artery disease; 1829 consented to randomization, and 2010 did not but were followed up in a registry. Thus, we can evaluate the outcome of physician-guided versus random assignment of percutaneous transluminal coronary angioplasty (PTCA) versus coronary artery bypass graft surgery (CABG).

METHODS AND RESULTS

We compared the baseline features and outcomes for PTCA and CABG in the overall registry and its predesignated subgroups. We assessed the impact of treatment by choice versus random assignment by comparing the results in the registry with those of the randomized trial. Statistical adjustments for differences in baseline characteristics were made. Within the registry, nearly twice as many patients were selected for PTCA (1189) as CABG (625); mortality at 7 years was similar for PTCA (13.9%) and CABG (14.2%) (P=0.66) before and after adjustment for baseline differences between patients selected for PTCA versus CABG (adjusted RR, 1.02; P=0.86). In contrast to the randomized trial, the 7-year mortality rate of treated diabetics in the registry was equally high (26%) with PTCA or CABG. Seven-year mortality was higher for patients undergoing PTCA in the randomized trial than in the registry (19.1% versus 13.9%, P<0.01) but not for those undergoing CABG (15.6% versus 14.2%, P=0.57). The adjusted relative mortality risk for PTCA in the randomized versus registry population was 1.17 (P=0.16).

CONCLUSIONS

BARI physicians were able to select PTCA rather than CABG for 65% of registry patients who underwent revascularization without compromising long-term survival either in the overall population or in treated diabetics.

Tryptase and agonists of PAR-2 induce the proliferation of human airway smooth muscle cells

Airway remodeling with smooth muscle cell (SMC) hyperplasia is a feature of chronic asthma. We investigated the potential for tryptase, the major secretory product of human mast cells, to act as a growth factor for human airway SMCs. Because this serine protease can activate proteinase-activated receptor-2 (PAR-2), we also examined the actions of SLIGKV, a peptide agonist of PAR-2. Incubation with lung tryptase provoked a twofold increase in [(3)H]thymidine incorporation; a similar increase in cell numbers was found when we used the MTS assay. The effect was catalytic site dependent, being abolished by the protease inhibitors leupeptin and benzamidine and by heat inactivation of the enzyme. Tryptase-induced DNA synthesis was inhibited by preincubation of the cells with pertussis toxin, calphostin C, or genistein. Transduction mechanisms are thus likely to involve a pertussis toxin-sensitive G protein, protein kinase C, and tyrosine kinase. SLIGKV elicited a response on SMCs similar to that of tryptase. Tryptase could provide an important stimulus for SMC proliferation in asthmatic airways, by acting on PAR-2.

Clopidogrel versus ticlopidine after intracoronary stent placement

OBJECTIVES

The study compared the safety and efficacy of ticlopidine with clopidogrel in patients receiving coronary stents.

BACKGROUND

Stent thrombosis is reduced when ticlopidine is administered with aspirin. Clopidogrel is similar to ticlopidine in chemical structure and function but has fewer side effects; few data are available about its use in stent patients.

METHODS

We compared 30-day event rates in 500 consecutive coronary stent patients treated with aspirin and clopidogrel (300 mg loading dose immediately prior to stent placement, and 75 mg/day for 14 days) to 827 consecutive stent patients treated with aspirin and ticlopidine (500 mg loading dose and 250 mg twice daily for 14 days).

RESULTS

Patients treated with clopidogrel had more adverse clinical characteristics including older age, more severe angina, and more frequent infarction within the prior 24 h. Nonetheless, mortality was 0.4% in clopidogrel patients versus 1.1% in ticlopidine patients; nonfatal myocardial infarction occurred in 0% versus 0.5%, stent thrombosis in 0.2% versus 0.7%, bypass surgery or repeat angioplasty in 0.4% versus 0.5%, and any event occurred in 0.8% versus 1.6% of patients, respectively (p = NS). Based on the observed 30-day event rate of 1.6% with ticlopidine, the statistical power of the study was 43% to detect an even rate of 0.5% with clopidogrel, and 75% to detect an event rate with of 4% with clopidogrel, with a p value of 0.05.

CONCLUSIONS

These data indicate that clopidogrel can be safely substituted for ticlopidine in patients receiving coronary stents.

A multicenter, randomized trial of coronary angioplasty versus directional atherectomy for patients with saphenous vein bypass graft lesions. CAVEAT-II Investigators

BACKGROUND

Directional coronary atherectomy and percutaneous transluminal coronary angioplasty have both been used in symptomatic patients with coronary saphenous vein bypass graft stenoses. The relative merits of plaque excision and removal versus balloon dilatation remain uncertain. We compared outcomes after directional coronary atherectomy or angioplasty in patients with de novo bypass graft stenoses.

METHODS AND RESULTS

Fifty-four North American and European sites randomized 305 patients with de novo vein graft lesions to atherectomy (n = 149) or angioplasty (n = 156). Quantitative coronary angiography at a core laboratory assessed initial and 6-month results. Initial angiographic success was greater with atherectomy (89.2% versus 79.0%), as was initial luminal gain (1.45 versus 1.12 mm, P < .001). Distal embolization was increased with atherectomy (P = .012), and a trend was shown toward more non-Q-wave myocardial infarction (P = .09). Although the 6-month net minimum luminal diameter gain was 0.68 mm for atherectomy and 0.50 mm for angioplasty, the restenosis rates were similar, 45.6% for atherectomy and 50.5% for angioplasty (P = .491). At 6 months, there was a trend toward decreased repeated target-vessel interventions for atherectomy (P = .092); in addition, 13.2% of patients treated with atherectomy versus 22.4% of the angioplasty patients (P = .041) required repeated percutaneous intervention of the initial target lesion.

CONCLUSIONS

Atherectomy of de novo vein graft lesions was associated with improved initial angiographic success and luminal diameter but also with increased distal embolization. There was no difference in 6-month restenosis rates, although primary atherectomy patients tended to require fewer target-vessel revascularization procedures.

Pathophysiology of bronchial smooth muscle remodelling in asthma

Whereas the role of bronchial smooth muscle remains controversial in healthy subjects its role is well established in asthmatics. Bronchial smooth muscle contraction induces airway narrowing. The smooth muscle also contributes to bronchial inflammation by secreting a range of inflammatory mediators, recruiting and activating inflammatory cells, such as mast cells or T-lymphocytes. In addition, bronchial smooth muscle mass is significantly increased in asthma. Such an increase has been related to a deposition of extracellular matrix proteins, and an increase in both cell size and number. However, the mechanisms of this smooth muscle remodelling are complex and not completely understood. The article will review recent data regarding the pathophysiology of bronchial smooth muscle remodelling in asthma.

Deletion of an N-terminal regulatory domain of the c-abl tyrosine kinase activates its oncogenic potential

The requirements for the oncogenic conversion of the c-abl proto-oncogene have been determined by the expression of N-terminal deleted forms and viral gag-fused forms of the c-abl proteins from a selectable retroviral vector. To activate the transforming potential of c-abl, it is necessary that (i) specific N-terminal amino acids are deleted to release the kinase from negative regulation in vivo; (ii) an N-terminal myristylation site is part of the activated kinase; (iii) the fatty-acylated, activated kinase is overproduced. The N-terminal amino acids found to be necessary for the cellular inhibition of c-abl tyrosine phosphorylation are part of a homologous region present in many non-receptor tyrosine kinases, the v-crk oncogene and phospholipase C-II. Overproduction of a deregulated and myristylated c-abl tyrosine kinase induces the transformation of NIH 3T3 cells.

Cell adhesion molecules NgCAM and axonin-1 form heterodimers in the neuronal membrane and cooperate in neurite outgrowth promotion

The axonal surface glycoproteins neuronglia cell adhesion molecule (NgCAM) and axonin-1 promote cell-cell adhesion, neurite outgrowth and fasciculation, and are involved in growth cone guidance. A direct binding between NgCAM and axonin-1 has been demonstrated using isolated molecules conjugated to the surface of fluorescent microspheres. By expressing NgCAM and axonin-1 in myeloma cells and performing cell aggregation assays, we found that NgCAM and axonin-1 cannot bind when present on the surface of different cells. In contrast, the cocapping of axonin-1 upon antibody-induced capping of NgCAM on the surface of CV-1 cells coexpressing NgCAM and axonin-1 and the selective chemical cross-linking of the two molecules in low density cultures of dorsal root ganglia neurons indicated a specific and direct binding of axonin-1 and Ng-CAM in the plane of the same membrane. Suppression of the axonin-1 translation by antisense oligonucleotides prevented neurite outgrowth in dissociated dorsal root ganglia neurons cultured on an NgCAM substratum, indicating that neurite outgrowth on NgCAM substratum requires axonin-1. Based on these and previous results, which implicated NgCAM as the neuronal receptor involved in neurite outgrowth on NgCAM substratum, we concluded that neurite outgrowth on an NgCAM substratum depends on two essential interactions of growth cone NgCAM: a trans-interaction with substratum NgCAM and a cis-interaction with axonin-1 residing in the same growth cone membrane.

Inflammation of bronchial smooth muscle in allergic asthma

BACKGROUND

Recent observations in asthma suggest that bronchial smooth muscle is infiltrated by inflammatory cells including mast cells. Such an infiltration may contribute to airway remodelling that is partly due to an increase in smooth muscle mass. Whether muscle increase is the result of smooth muscle cell hypertrophy remains controversial and has not been studied by ultrastructural analysis. A morphometric analysis of airway smooth muscle (ASM) was undertaken in asthmatic patients using electron microscopy to examine the interactions between ASM cells and inflammatory cells.

METHODS

ASM specimens were obtained from 14 asthmatic subjects and nine non-asthmatic controls undergoing fibreoptic endoscopy. Inflammatory cell counts were assessed by immunohistochemistry, and ultrastructural parameters were measured using electron microscopy in a blinded fashion on smooth muscle cells and inflammatory cells.

RESULTS

ASM from asthmatic patients was infiltrated by an increased number of mast cells and lymphocytes. Smooth muscle cells and their basal lamina were thicker in asthmatic patients (9.5 (0.8) and 1.4 (0.2) microm) than in controls (6.7 (0.4) and 0.7 (0.1) microm). In asthmatics the extracellular matrix was frequently organised in large amounts between ASM cells. Myofibroblasts within smooth muscle bundles were only observed in asthmatics, some of them displaying a close contact with ASM cells.

CONCLUSION

In asthma, airway myositis is characterised by a direct interaction between ASM cells and mast cells and lymphocytes. Smooth muscle remodelling was present, including cell hypertrophy and abnormal extracellular matrix deposition moulding ASM cells.

Cardiogenic shock complicating acute coronary syndromes

Cardiogenic shock remains the major cause of death among patients with all types of acute coronary syndromes. Thus, there is a growing interest in the identification of patients who are at risk for developing cardiogenic shock, in the exploration of different therapeutic approaches to preventing its development, and in the improvement of outcome when it occurs. This article reviews the aetiology and pathophysiology of cardiogenic shock, its epidemiology, its treatment (including pharmaceutical agents, counterpulsation, and revascularisation), and its outcome. Algorithms are presented that predict its occurrence in both ST-segment-elevation myocardial infarction and unstable angina or non-ST-elevation myocardial infarction, and that predict its mortality in patients with ST-segment-elevation acute myocardial infarction. Such new areas as metabolic therapy and glycoprotein IIb/IIIa inhibitors are discussed, as are the economic implications of shock.