P6411Dyspnea in ticagrelor treated patients in the all-comer randomized GLOBAL LEADERS study and its association with clinical outcomes

Background

Dyspnea represents a drug adverse effect reported with a higher frequency for ticagrelor, as compared with other P2Y12 antagonists. The impact of dyspnea on clinical outcomes has not been yet evaluated in the context of aspirin-free therapies after percutaneous coronary intervention (PCI).

Purpose

The study aimed to evaluate the incidence of dyspnea and its associations with demographic characteristics and clinical outcomes in patients undergoing PCI treated with ticagrelor either as monotherapy or as a part of a dual antiplatelet therapy (DAPT) in the GLOBAL LEADERS cohort.

Methods

This is a sub-analysis of the randomized all-comer GLOBAL LEADERS study (n=15991), comparing the experimental strategy of ticagrelor monotherapy following one-month DAPT after PCI with the reference strategy of 12-month DAPT followed by 12-month aspirin monotherapy. The incidence of dyspnea reported as adverse event (AE) and its relation to demographic characteristics and 2-year clinical outcomes was evaluated (intention-to-treat analysis). Multivariable Cox proportional hazards models were performed, including randomized treatment and incidence of first dyspnea event as a time-dependent covariate. The primary endpoint was a composite of 2-year all-cause mortality or centrally adjudicated, new Q-wave myocardial infarction (MI). Patient-oriented clinical endpoints (POCE) comprised all-cause death, any stroke, MI or revascularization, whereas net adverse clinical events (NACE) included POCE and Bleeding Academic Research Consortium (BARC)-defined bleeding type 3 or 5.

Results

Overall, dyspnea was reported as an AE in 2101 patients (13.2%) up to two years of follow-up, with a higher frequency in the experimental arm (16.4%) as compared with the reference group (11.1%) (hazard ratio [HR]1.70, 95% confidence interval [CI] 1.56–1.86, p=0.001).

Predictors of dyspnea AE up to 2 years by multivariate analyses were: chronic obstructive pulmonary disease (HR1.71, 95% CI 1.56–1.87, p=0.001), female gender (HR1.31, 95% CI 1.18–1.44, p=0.001), hypertension (HR1.31, 95% CI 1.19–1.44, p=0.001, prior coronary artery bypass grafting (HR1.30, 95% CI 1.10–1.54, p=0.003), left ventricle ejection fraction below 40% (HR1.22, 95% CI 1.04–1.42, p=0.012), presentation with acute coronary syndrome (HR1.19, 95% CI 1.09–1.29, p=0.001) and body mass index (≥27kg/m2) (HR1.17, 95% CI 1.08–1.28, p=0.001).

In patients who reported dyspnea AE, the two-year rates of the efficacy and safety endpoints in the experimental and reference arm were: for the primary endpoint 3.4% vs. 4.3% (p adjusted=0.807), for POCE 15.8% vs. 17.6% (p adjusted=0.218), for NACE 17.2% vs. 19.6% (p adjusted=0.082), for BARC 3 or 5 type bleeding 17.2% vs. 19.6% (p adjusted=0.082), respectively.

Conclusions

The occurrence of dyspnea AE up to two years after PCI appeared not to affect the safety of the experimental treatment strategy of 23-month ticagrelor monotherapy following one-month DAPT after PCI.

Acknowledgement/Funding

Study founded by European Cardiovascular Research Institute, which received unrestricted grants from Biosensors Int., AstraZeneca, Medicines Company.

Fibroblast-derived exosomes promote epithelial cell proliferation through TGF-β2 signalling pathway in severe asthma

BACKGROUND

Bronchial fibroblasts play a key role in airway remodelling in asthma. They regulate epithelial cell functions such as proliferation through growth factors, cytokines, chemokines and exosomes. The role of exosomes in the communication between epithelial cells and fibroblasts by vehiculing these mediators in asthma remains to be determined.

OBJECTIVE

To evaluate the role of exosomes released by bronchial fibroblasts on epithelial cell proliferation in severe asthma.

METHODS

Exosomes were obtained from culture media of primary bronchial fibroblasts and characterized using Western blot, electron microscopy and flow cytometry. Uptake profile of fluorescent-labelled exosomes in epithelial cells was assessed by flow cytometry. Exosome cytokine content was analysed by Cytokine Arrays. Bronchial epithelial cell proliferation was evaluated by BrdU incorporation test. Exosome biogenesis/release was blocked using sphingomyelinase inhibitor. Plasmid transfection was used to modulate transforming growth factor beta 2 (TGF-β2) gene expression.

RESULTS

We showed that bronchial fibroblasts secreted exosomes, which were internalized by bronchial epithelial cells. Exosomes of severe asthmatic subjects' fibroblasts showed a lower level of TGF-β2 and significantly increased the epithelial cell proliferation of both healthy and severe asthmatic subjects compared to healthy controls' exosomes. Overexpression of TGF-β2 in severe asthmatics' fibroblasts induced enhanced TGF-β2 in exosomes leading to a reduced proliferation of epithelial cells, whereas knockdown of TGF-β2 enhanced epithelial cell proliferation.

CONCLUSION

Our study shows that exosomes are involved in fine-tuning intercellular communication in asthma. Exosomes of severe eosinophilic asthmatics' fibroblasts can contribute to airway remodelling, at least in part, by modulating epithelial cell proliferation observed in severe asthma.

MicroRNA-19a enhances proliferation of bronchial epithelial cells by targeting TGFβR2 gene in severe asthma

BACKGROUND

Allergic asthma is characterized by inflammation and airway remodeling. Bronchial epithelium is considered a key player in coordinating airway wall remodeling. In mild asthma, the epithelium is damaged and fails to proliferate and to repair, whereas in severe asthma, the epithelium is highly proliferative and thicker. This may be due to different regulatory mechanisms. The purpose of our study was to determine the role of miRNAs in regulating proliferation of bronchial epithelial cells obtained from severe asthmatic subjects in comparison with cells obtained from mild asthmatics and healthy controls.

METHODS

Human bronchial epithelial cells (BEC) were isolated by bronchoscopy from bronchial biopsies of healthy donors and patients with mild and severe asthma. MiRNA expression was evaluated using the TaqMan low-density arrays and qRT-PCR. Transfection studies of bronchial epithelial cells were performed to determine the target genes. Cell proliferation was evaluated by BrdU incorporation test.

RESULTS

MiR-19a was upregulated in epithelia of severe asthmatic subjects compared with cells from mild asthmatics and healthy controls. Functional studies based on luciferase reporter and Western blot assays suggest that miR-19a enhances cell proliferation of BEC in severe asthma through targeting TGF-β receptor 2 mRNA. Moreover, repressed expression of miR-19a increased SMAD3 phosphorylation through TGF-β receptor 2 signaling and abrogated BEC proliferation.

CONCLUSION

Our study uncovers a new regulatory pathway involving miR-19a that is critical to the severe phenotype of asthma and indicates that downregulating miR-19a expression could be explored as a potential new therapy to modulate epithelium repair in asthma.

Cysteinyl leukotrienes regulate TGF-β(1) and collagen production by bronchial fibroblasts obtained from asthmatic subjects

BACKGROUND

Cysteinyl leukotrienes (CysLTs) play an important role in airway inflammation in asthma but their role in airway remodeling is not completely known.

METHODS

CysLTs receptors and procollagen I(α(1)) mRNA were determined by qPCR. Procollagen protein production was measured by RIA and TGF-β(1) expression was determined by ELISA. TGF-β receptor expression was assessed by western blots.

RESULTS

CysLT1R, TGF-β-R1 and active TGF-β(1) are highly expressed in cells from asthmatics compared to normal controls. LTD(4) increased significantly procollagen I(α(1)) mRNA and protein expression in fibroblasts from asthmatics. This increase was blocked by CysLTs receptor antagonist. LTD(4) increased significantly mRNA expression of TGF-β(1) and active form production in fibroblasts from asthmatics. Inhibition of TGF-β(1) signaling blocked LTD(4)-induced procollagen I(α(1)) expression.

CONCLUSIONS

Fibroblasts from asthmatic subjects express high level of CysLT1R. LTD(4) regulates procollagen I(α(1)) transcription in fibroblasts derived from asthmatic patients by modulating TGF-β(1) expression. This suggests that CysLTs may play a role in regulating collagen deposition in asthma.

Mechanical strain increases cytokine and chemokine production in bronchial fibroblasts from asthmatic patients

BACKGROUND

Mechanical strain and cytokine stimulation are two important mechanisms leading to airway remodeling in asthma. The effect of mechanical strain on cytokine secretion in airway fibroblasts is not known. The aim of this study was to determine whether bronchial and nasal fibroblasts differentially alter cytokine secretion in response to mechanical strain.

METHODS

We measured secretion of the pro-fibrotic cytokine, interleukin-6 (IL-6), and the pro-inflammatory cytokines, IL-8 and monocyte chemotactic protein 1, before and after mechanical strain in bronchial fibroblasts obtained from asthmatic patients [asthmatic bronchial fibroblasts (BAF)] and normal volunteers [normal bronchial fibroblasts (BNF)], and in nasal fibroblasts (NF) obtained from nasal polyps. Cells were grown on flexible membranes and a mechanical strain of 30% amplitude, 1 Hz frequency was applied for 3, 6 and 24 h. Control cells were unstrained. IL-6, IL-8 and monocyte chemotactic protein 1 was measured after 24 h strain using enzyme-linked immunoassay; mRNA was measured by real time polymerase chain reaction. We also measured mRNA for versican, a matrix proteoglycan, known to be upregulated in the asthmatic airway wall.

RESULTS

In unstrained conditions, no differences in cytokine secretion were observed. After 24 h strain, BAF secreted more IL-6 than BNF. Mechanical strain increased IL-8 mRNA in BAF, BNF and NF; and IL-6 and versican mRNA, in BAF, only.

CONCLUSIONS

Cytokine responses to mechanical strain varied in different airway fibroblast populations, and depended on the site of origin, and the underlying inflammatory state. Strain resulted in IL-6 upregulation and increased message for extracellular matrix protein in bronchial fibroblasts from asthmatic patients only, and may reflect these patients' propensity for airway remodeling.

Angiogenic gene therapy in patients with nonrevascularizable ischemic heart disease: a phase 2 randomized, controlled trial of AdVEGF121 (AdVEGF121) versus maximum medical treatment

The demonstration that angiogenic growth factors can stimulate new blood vessel growth and restore perfusion in animal models of myocardial ischemia has led to the development of strategies designed for the local production of angiogenic growth factors in patients who are not candidates for conventional revascularization. The results of recent clinical trials of proangiogenesis gene therapy have been disappointing; however, significant limitations in experimental design, in particular in gene transfer strategies, preclude drawing definitive conclusions. In the REVASC study cardiac gene transfer was optimized by direct intramyocardial delivery of a replication-deficient adenovirus-containing vascular endothelial growth factor (AdVEGF121, 4 x 10(10) particle units (p.u.)). Sixty-seven patients with severe angina due to coronary artery disease and no conventional options for revascularization were randomized to AdVEGF121 gene transfer via mini-thoracotomy or continuation of maximal medical treatment. Exercise time to 1 mm ST-segment depression, the predefined primary end-point analysis, was significantly increased in the AdVEGF121 group compared to control at 26 weeks (P=0.026), but not at 12 weeks. As well, total exercise duration and time to moderate angina at weeks 12 and 26, and in angina symptoms as measured by the Canadian Cardiovascular Society Angina Class and Seattle Angina Questionnaire were all improved by VEGF gene transfer (all P-values at 12 and 26 weeks < or =0.001). However, if anything the results of nuclear perfusion imaging favored the control group, although the AdVEGF121 group achieved higher workloads. Overall there was no significant difference in adverse events between the two groups, despite the fact that procedure-related events were seen only in the thoracotomy group. Therefore, administration of AdVEGF121 by direct intramyocardial injections resulted in objective improvement in exercise-induced ischemia in patients with refractory ischemic heart disease.

Platelet GPIIb/IIIa receptor blockade reduces infarct size in a canine model of ischemia-reperfusion

OBJECTIVES

We studied the effects of N-acetyl-cys-asn-(5,5-dimethyl-4-thiazolidine-carbonyl)-4-amino-methyl-phe-gly-asp-cys, monoacetate (MK-0852) (platelet GPIIb/IIIa receptor blocker) on peak reactive hyperemia, distribution of blood flow, regional contractile function and infarct size in a canine model of acute ischemia-reperfusion injury.

BACKGROUND

Platelet activation and formation of platelet microaggregates in coronary vessels could contribute to ischemia-induced myocyte injury. Inhibition of platelet aggregation could reduce ischemia-reperfusion injury.

METHODS

Three groups of dogs (n = 10/group) were studied; group 1--heparin (HEP) (100 U/kg/h intravenously), group 2--MK-0852 (300 microg/kg intravenous bolus followed by 3 microg/kg/min for 3 h) and group 3--MK-0852 plus HEP. Infarct size after 60 min regional ischemia and 3 h reperfusion was evaluated by tetrazolium staining and normalized to risk area (Monastral blue dye).

RESULTS

Infarct size in HEP-treated controls was 32.4+/-2.8%; in MK-0852 without or with HEP groups, infarct size was 17.4+/-1.9% (p = 0.001) and 23.4+/-3.0% (p = 0.04), respectively. Cardiac hemodynamics and rate-pressure product were comparable between groups. Multivariate analysis using collateral blood flow as the independent variable confirmed the cytoprotective actions of MK-0852. Postischemic peak reactive hyperemia in the infarct-related artery was depressed in all groups; during reperfusion, transmural distribution of myocardial blood flow returned to near control levels, but severe regional hypokinesia persisted.

CONCLUSIONS

Diminished infarct size with MK-0852 treatment suggests an additional mechanism of benefit for GPIIb/IIIa blockers beyond stabilization of a "culprit" acute coronary lesion. This cytoprotective effect was unrelated to preservation of coronary vasoreactivity (assessed by reactive hyperemia), restoration of blood flow across the myocardium or acute improvement in contractility.

Long-term effects of cholesterol lowering and angiotensin-converting enzyme inhibition on coronary atherosclerosis: The Simvastatin/Enalapril Coronary Atherosclerosis Trial (SCAT)

BACKGROUND

This long-term, multicenter, randomized, double-blind, placebo-controlled, 2 x 2 factorial, angiographic trial evaluated the effects of cholesterol lowering and angiotensin-converting enzyme inhibition on coronary atherosclerosis in normocholesterolemic patients.

METHODS AND RESULTS

There were a total of 460 patients: 230 received simvastatin and 230, a simvastatin placebo, and 229 received enalapril and 231, an enalapril placebo (some subjects received both drugs and some received a double placebo). Mean baseline measurements were as follows: cholesterol level, 5.20 mmol/L; triglyceride level, 1.82 mmol/L; HDL, 0.99 mmol/L; and LDL, 3.36 mmol/L. Average follow-up was 47.8 months. Changes in quantitative coronary angiographic measures between simvastatin and placebo, respectively, were as follows: mean diameters, -0.07 versus -0.14 mm (P:=0.004); minimum diameters, -0.09 versus -0.16 mm (P:=0. 0001); and percent diameter stenosis, 1.67% versus 3.83% (P:=0.0003). These benefits were not observed in patients on enalapril when compared with placebo. No additional benefits were seen in the group receiving both drugs. Simvastatin patients had less need for percutaneous transluminal coronary angioplasty (8 versus 21 events; P:=0.020), and fewer enalapril patients experienced the combined end point of death/myocardial infarction/stroke (16 versus 30; P:=0.043) than their respective placebo patients.

CONCLUSIONS

This trial extends the observation of the beneficial angiographic effects of lipid-lowering therapy to normocholesterolemic patients. The implications of the neutral angiographic effects of angiotensin-converting enzyme inhibition are uncertain, but they deserve further investigation in light of the positive clinical benefits suggested here and seen elsewhere.

Ischemia-induced action potential shortening is blunted by d-sotalol in a pig model of reversible myocardial ischemia

The purpose of this study was to investigate, in an anesthetized pig model of low-flow myocardial ischemia, the electrophysiologic effects of the class III drug d-sotalol during myocardial ischemia. Serial monophasic action potential (MAPD90) recordings and refractory period determinations from the anterior and posterior left ventricular wall were taken in 25 pigs during baseline, after low-flow posterior wall ischemia, after d-sotalol infusion under nonischemic conditions, and after repeated posterior wall ischemia while continuing the drug. Measurements were done at 60 and 150 beats/min after radiofrequency ablation of atrioventricular conduction. At baseline, MAPD90 and refractory periods were comparable in the anterior and posterior wall (323 +/- 15 vs. 318 +/- 10 ms, and 267 +/- 10 vs. 262 +/- 11 ms at 60 beats/min, respectively). In the absence of d-sotalol, low-flow regional ischemia was associated with a significant shortening of MAPD90 in the posterior versus the anterior wall (267 +/- 20 vs. 317 +/- 20 ms at 60 beats/min; p = 0.006). Similarly, ischemia-induced shortening of the refractory periods in the posterior wall was apparent (230 +/- 16 ms in the posterior wall vs. 274 +/- 14 ms in the anterior wall at 60 beats/min). In contrast, ischemia was no longer associated with shortening of MAPD90 (360 +/- 17 ms posterior wall and 360 +/- 20 ms anterior wall at 60 beats/min) and refractory periods (304 +/- 19 ms posterior wall vs. 316 +/- 15 ms anterior wall at 60 beats/min) during combined posterior wall ischemia and d-sotalol infusion. Similar findings were obtained during pacing at 150 beats/min. d-Sotalol attenuates ischemia-induced action potential shortening. This property should decrease dispersion of cardiac repolarization and be antiarrhythmic. On the other hand, longer APD under ischemic conditions may favor calcium overload, which may trigger new arrhythmias.

Comparison of propafenone versus procainamide for the acute treatment of atrial fibrillation after cardiac surgery

A prospective, randomized, double-blind study to compare the efficacy in terminating postoperative atrial fibrillation of the class Ic drug propafenone versus class Ia drug procainamide was conducted. Intravenous propafenone was superior to procainamide in achieving rapid cardioversion and a better rate control with a lower incidence of symptomatic hypotension.

Block of potassium currents in guinea pig ventricular myocytes and lengthening of cardiac repolarization in man by the histamine H1 receptor antagonist diphenhydramine

Treatment with second generation histamine H1 receptor antagonists has been associated with lengthening of the Q-T interval and proarrhythmia. Similarly, lengthening of the Q-T interval has been reported in patients after overdosing with diphenhydramine (DPH), a first generation agent. Therefore, our study was designed 1) to assess effects of DPH on cardiac repolarization and 2) to characterize effects of the drug on major voltage-dependent cardiac K+ currents. First, we noticed that oral administration of DPH at usual dosages to healthy volunteers or to patients (prior to angioplasty) was associated with prolongation of the Q-Tc interval. Although this effect was modest in most individuals, Q-Tc was increased more than 20 ms in 7 of 20 patients. Second, we noticed that exposure of isolated guinea pig hearts to DPH 10(-5) M caused a lengthening of monophasic action potential duration. This effect was potentiated by the combined perfusion of other K+ channel blockers such as indapamide. Finally, experiments performed with the patch-clamp technique demonstrated unequivocal block of the rapid component of the delayed rectifier (IKr) by DPH; however, IC50 determined for block of IKr (3 x 10(-5) M) is approximately 40-fold greater than plasma concentrations of the drug measured at usual dosages (7 x 10(-7) M). Consequently, in agreement with the long-term clinical use of the drug, prolongation of cardiac repolarization should be minimal in most patients at usual dosages but may be observed with overdosing. Nevertheless, caution remains since excessive lengthening of cardiac repolarization may occur after administration of DPH with other drugs due to 1) concomitant block of other ionic currents or 2) pharmacokinetic interactions leading to toxic concentrations of DPH.

Attenuation of myocardial ischemia with repeated exercise in subjects with chronic stable angina: relation to myocardial contractility, intensity of exercise and the adenosine triphosphate-sensitive potassium channel

OBJECTIVES

This study characterized the attenuation of myocardial ischemia observed with re-exercise to determine whether: 1) a differing exercise intensity modifies this attenuation; 2) it could be explained by contractile down-regulation or stunning; 3) it is mediated by activation of ATP-sensitive potassium channels (K+-ATP).

BACKGROUND

Subjects with ischemic heart disease (IHD) frequently note less angina with re-exercise after a brief rest. Potential mechanisms of this 'warm-up' phenomenon have been little explored.

METHODS

IHD subjects with a positive exercise test were studied. Groups I and II (12 subjects each) underwent 2 successive Naughton protocol exercise echocardiography tests (with 1 min instead of 2 min stages for Group II). Group D (10 subjects) had type II diabetes, were on > or =10 mg daily of the K+-ATP blocker, glibenclamide, and underwent the group I exercise protocol. The ischemic threshold or rate-pressure product at 1 mm ST segment depression, ST depression corresponding to the peak rate-pressure product of the first exercise (maximum ST depression equivalent), and left ventricular wall motion indexes before and immediately after each exercise were analyzed.

RESULTS

Exercise-induced myocardial ischemia with re-exercise was similarly attenuated in groups I, II, and D. The ischemic threshold was raised by nearly 20% with re-exercise (p=0.001, p=0.02, and p=0.02, respectively) and the maximum ST depression equivalent was nearly halved on re-exercise (p=0.005, p=0.006, and p=0.001, respectively). Exercise-induced wall motion dysfunction was attenuated with re-exercise. In group I, wall motion returned to the initial baseline score prior to exercise 2, whereas in the more intense protocol of group II, wall motion dysfunction persisted prior to exercise 2.

CONCLUSIONS

Thus, the attenuation of myocardial ischemia observed with re-exercise appears to be independent of the intensity of the exercise protocol and is not explained by down-regulation of myocardial contractility induced by the initial ischemic stimulus. Since results were similar in diabetic subjects on robust doses of glibenclamide, this phenomenon does not appear to be mediated by K+-ATP activation.

Health promotion and early detection of cancer in older adults: needs assessment for program development

The greatest risk factor for developing cancer is age, yet little is known about the cancer-related knowledge, attitudes and beliefs of the older adult (age > 55 years). A community-based needs assessment was conducted to understand these dimensions in a large metropolitan community. Ten focus groups (n = 158 older adults) and 9 individuals were interviewed. Content analysis for the audiotaped sessions was completed. The study participants focused on "being active" and living a healthy lifestyle. Many worried about illness interfering with their ability to do what they wanted to do. Many had had exposure to cancer through family members or friends, but still had many unanswered questions about cancer. Age was not seen as a risk factor for cancer, and a range of attitudes existed regarding cancer prevention and early detection. Overall, despite fearing cancer, participants thought older adults needed to know about cancer and suggested a wide range of approaches to disseminate information effectively to older adults.

Health promotion and early detection of cancer in older adults: assessing knowledge about cancer

PURPOSE/OBJECTIVES

To identify the knowledge level concerning cancer in older Canadian adults.

DESIGN

Descriptive.

SETTING

Urban community in Canada.

SAMPLE

Convenience sample of 513 adults over the age of 55 (72% female; 68% born in countries other than Canada).

METHODS

A self-report questionnaire, the Cancer Knowledge Survey for Elders, was administered to participants in their native language (eight different language groups). Distribution was through community workers and public healthy nurses who worked with older adults.

MAIN RESEARCH VARIABLES

Knowledge about cancer, language group, length of time living in the country.

FINDINGS

The highest number of correct responses (87%) was for the item "Can some cancers be cured if they are discovered early?" The highest number of wrong answers (67%) was for the item "Can a bump or bruise to the body cause cancer?" Sixty-six percent did not consider age as a risk factor. For all but three items, the proportion of English language to non-English language individuals with correct answers was significantly different individuals whose native language was not English were less knowledgeable about cancer.

IMPLICATIONS FOR NURSING PRACTICE

This study offers a basis for a large multicultural survey. Should the observations be confirmed in a larger sample, implications exist for public education about the risk factors and signs and symptoms of cancer, especially with individuals for whom English is not a native language.

CONCLUSIONS

In this sample, specific areas were identified in which knowledge about cancer was lacking. In particular, the increased risk of cancer with advancing age was not recognized by a significant portion of study participants.

Rationale and design features of a clinical trial examining the effects of cholesterol lowering and angiotensin-converting enzyme inhibition on coronary atherosclerosis: Simvastatin/Enalapril Coronary Atherosclerosis Trial (SCAT). SCAT Investigators

BACKGROUND

In the treatment of coronary atherosclerotic artery disease (CAD), the mechanisms by which lipid lowering, a proven therapy, produces beneficial clinical effects remain unclear. Moreover, although potential mechanisms of benefit are well known and increasingly applied clinically, there are no conclusive data from clinical trials studying primarily the antiischemic effects of angiotensin-converting enzyme (ACE) inhibition in patients with normal heart function. The Simvastatin/Enalapril Coronary Atherosclerosis Trial (SCAT) is designed to clarify some of these issues in CAD patients with normal or mildly elevated cholesterol. DESIGN AND OBJECTIVES: SCAT is a three- to five-year, multicentre, randomized, double-blind, placebo controlled, 2 x 2 factorial trial evaluating the effects of cholesterol lowering therapy by simvastatin and/or ACE inhibition by enalapril on anatomic coronary atherosclerosis progression assessed by quantitative coronary angiography in CAD patients with preserved left ventricular function and total cholesterol levels between 4.1 and 6.2 mmol/L.

PATIENTS

Of 460 patients (age 61 +/- 9 years; 409 males, 51 females) enrolled between June 1991 and July 1995, 230 were randomized to simvastatin and 230 to placebo, and 229 to enalapril and 231 to placebo. Average baseline total cholesterol level was 5.20 +/- 0.61 mmol/L, high density lipoprotein cholesterol was 0.99 +/- 0.25 mmol/L, low density lipoprotein cholesterol was 3.36 +/- 0.57 mmol/L and triglycerides were 1.82 +/- 0.75 mmol/L. The trial will be completed in June 1998.

SIGNIFICANCE

Insights gained from this long term angiographic trial will lead to a better understanding of the mechanisms of benefits of these two treatments, both alone and in combination. Of particular interest is that this trial will be able to examine a suspected beneficial interaction, if present, between these two treatments.

Health promotion and early detection of cancer in older adults: a practical approach

Little is known about the cancer-related knowledge, attitudes and health behaviours of older adults (> 55 years), or about designing health promotion and early detection interventions responsive to their learning needs. A collaborative project was established with the intent of designing an appropriate program for older adults. The initial work included a community needs assessment using focus groups, one-on-one interviews and self-report surveys. The use of key community contacts was effective in locating older adult subjects (> 55 years) through pre-established linkages with agencies. Various ethnocultural groups, low income communities and isolated individuals, as well as other pre-established groups, were included in this study. The needs assessment found that: age is not perceived as a cancer risk factor; transportation is a barrier to screening; fear inhibits people from being screened; physicians are viewed as both the main source of expert cancer knowledge and as the gatekeepers to screening; family and peers are the main source of support, ethnospecific groups have different information needs; and finally, that lifestyle suggestions can reduce the risk of cancer. The findings indicated that community health promotion programs for older adults will require multiple approaches with a combination of strategies in order to meet their learning needs.

Absence of increased in-hospital complications with reused balloon catheters

A reanalysis of data from a prospective Canadian study suggests that catheter reuse is not associated with an increased rate of in-hospital complications. However, these results should be replicated in clinical trials before catheter reuse becomes routinely established.

Myocardial infarction patients in the 1990s--their risk factors, stratification and survival in Canada: the Canadian Assessment of Myocardial Infarction (CAMI) Study

OBJECTIVES

This study sought to evaluate the in-hospital and postdischarge mortality of patients with an acute myocardial infarction in the 1990s.

BACKGROUND

The widespread implementation of therapeutic interventions that modify the natural history of coronary artery disease has led to changes in the profile and survival of patients with an acute myocardial infarction. Although data exist for selected subsets of patients with an acute myocardial infarction, at this time there is little recent prospective information on all patients presenting with an acute myocardial infarction, particularly for survival after hospital discharge.

METHODS

All patients < or = 75 years old presenting with an acute myocardial infarction between July 1, 1990 and June 30, 1992 at nine Canadian hospitals were prospectively evaluated and followed up for 1 year. From November 1991, patients of all ages were included. In two centers, recruitment continued until December 31, 1992. A total of 3,178 patients were recruited.

RESULTS

The in-hospital mortality rate of patients < or = 75 years old was 8.4%, and that at 1 year after hospital discharge was 5.3%. For patients of all ages recruited after November 1, 1991, the in-hospital mortality rate was 9.9% and 7.1% for 1 year after hospital discharge. For patients < or = 75 years old, age carried an independent in-hospital but no post discharge risk. Female patients had a twofold greater risk of dying in hospital. After hospital discharge, only 1.7% of patients < or = 75 years old and 1.9% of patients of all ages died of a presumed arrhythmic death. Premature ventricular contractions had no independent prognostic value. The relatively low in-hospital (5.3%) and postdischarge (6.1%) reinfarction rate may have contributed to improved survival. A greater reinfarction rate in patients >75 years old (17.4% vs. 9.6%, p < 0.001) may have contributed to their poorer outcome.

CONCLUSIONS

One-year mortality after acute myocardial infarction continues to decrease, and changes in the prognostic value of traditional methods of risk stratification have occurred.

Reuse of balloon catheters for coronary angioplasty: a potential cost-saving strategy?

OBJECTIVES

This study was designed to determine the effectiveness, safety and costs associated with reuse of angioplasty catheters and to compare these results with those of a contemporary center that employed a single-use strategy.

BACKGROUND

Coronary angioplasty is an important but expensive procedure. To overcome the financial constraints of the Canadian health care system, reuse of angioplasty catheters is routinely practiced in some institutions.

METHODS

In a prospective observational study, data forms were completed after each angioplasty procedure and before patient discharge over a 10-month period.

RESULTS

A total of 693 patients underwent coronary angioplasty in the two centers. Clinical and lesion characteristics were similar except for a higher incidence of unstable angina at the reuse center (p < 0.005). The angiographic success rate was identical (88%) at both centers. The reuse center utilized more balloon catheters/lesion (mean +/- SD 2.4 +/- 1.5 vs. 1.2 +/- 0.5, p < 0.00001) and had a higher incidence of initial balloon failure (10.2% vs. 3.3%, p < 0.0001). Significant prolongation of the procedure time (81 +/- 41 vs. 68 +/- 32 min, p < 0.0001) and increased volume of contrast medium (201 +/- 86 vs. 165 +/- 61 ml, p < 0.0001) were seen in the reuse center. A higher rate of adverse clinical events (7.8% vs. 3.8%, p < 0.025) was observed in the reuse center, especially in patients with unstable angina.

CONCLUSIONS

The reuse strategy was associated with a higher rate of adverse events, prolonged procedure time and increased use of contrast medium, especially in lesions that were not crossed by the initial balloon and in patients with unstable angina. Whether these differences are related to the reuse strategy or to differences in patient groups cannot be ascertained by this observational study. A multicenter randomized trial is required to further assess the safety and the cost/benefit ratio of this strategy.

Porous balloon catheters for local delivery: assessment of vascular damage in a rabbit iliac angioplasty model

OBJECTIVES

This experimental study assessed long-term vascular damage induced by the use of porous balloon catheters designed for local delivery.

BACKGROUND

Local drug delivery using porous balloon catheters has emerged as a possible means by which compounds designed to prevent restenosis might be delivered locally at concentrations higher than achievable by systemic administration. There are, nonetheless, some concerns about the possibility of greater arterial trauma induced by the high pressure fluid jets from the delivery catheter itself, a complication that could provide additional stimulus for intimal hyperplasia. Because these concerns are based mainly on in vitro studies and on studies performed after acute experiments, further work is required to assess the long-term effects of this device on the arterial wall.

METHODS

Local delivery of a saline solution was performed in 32 rabbits in one iliac artery, using an inflation pressure of 6 atm and a balloon/artery ratio of 1.3 to 1.5, followed by angioplasty in both iliac arteries. Vascular injury was assessed using tritiated thymidine incorporation at 4 days (12 rabbits) and planimetry at 30 days after the procedure (20 rabbits).

RESULTS

Tritiated thymidine incorporation did not reveal any significant difference between the angioplasty group and the group with local delivery and angioplasty (117,921 +/- 18,853 vs. 140,652 +/- 23,125 cpm/mg protein, p = NS). Planimetry at 30 days was also similar in the two groups (neointimal area 0.11 +/- 0.02 vs. 0.13 +/- 0.02 mm2).

CONCLUSIONS

In this model the use of porous balloon catheters before angioplasty did not lead to greater intimal hyperplasia than angioplasty alone. Further experimental investigation is required to determine whether this strategy could be used to prevent postangioplasty restenosis in humans.

Histological changes in the aortic valve after balloon dilatation: evidence for a delayed healing process

OBJECTIVE

To investigate whether balloon dilatation of the aortic valve induces long-term macroscopic or histological changes or both to explain the restenosis process.

DESIGN

Prospective study of 39 consecutive patients. Sixteen later (mean (SD) 12 (10) months) required operation. This non-randomised subgroup was compared with 10 patients who had aortic valve replacement without prior dilatation.

SETTING

University cardiology and cardiac surgery centre and pathology department.

PATIENTS

16 patients who had aortic valve replacement because of failure of or restenosis after balloon dilatation of the aortic valve. Twelve resected valves were examined.

INTERVENTIONS

Percutaneous balloon dilatation of the aortic valve (maximal balloon size: trefoil 3 x 12 mm balloon or bifoil 2 x 19 mm balloon) and surgical inspection before excision of the aortic valve leaflets during open-chest aortic valve replacement. Fixation, decalcification, and staining for histology.

MAIN OUTCOME MEASURES

Presence of long-term pathological changes in the resected valve and their relation to restenosis after balloon dilatation.

RESULTS

Macroscopically the previously dilated valves were indistinguishable from valves from the patients who had valve replacement only. Microscopically, the dilated aortic valves showed areas of young scar tissue that were not seen in a control group of surgically excised stenotic aortic valves. This persistent scarring reaction was seen around small tears or lacerations of the collagenous valve stroma, fractures in calcified areas, and splits in commissures. Young scar tissue without collagenisation was still present 24 months after dilatation.

CONCLUSION

Organisation and collagenisation of scar tissue develops slowly after balloon dilatation of the aortic valve. This prolonged scarring reaction may explain the late development of restenosis in some patients.

Aortic valvuloplasty of calcific aortic stenosis with monofoil and trefoil balloon catheters: practical considerations. An evaluation of balloon design and valvular morphology relationship, derived from experimental and clinicopathological observations

In order to evaluate the relation between balloon design (monofoil, trefoil) and valvular configuration, experimental aortic valvuloplasty was performed in four post-mortem hearts with calcific aortic stenosis of various morphology. The degree of obstruction of the aortic orifice was assessed by computed axial tomography during inflation of monofoil 15 and 19 mm and trefoil 3 x 12 mm balloon catheters. We also evaluated the hemodynamic repercussion of balloon inflation (fall in systolic aortic pressure) in four elderly patients with acquired aortic stenosis who underwent a percutaneous transluminal aortic balloon valvuloplasty, with stepwise increasing balloon sizes of 15 mm, 19 mm and 3 x 12 mm, as during our in vitro experiments, and who underwent aortic valve replacement later on. In these patients, we correlated the anatomy of the excised aortic valves with the retrospective analysis of aortic pressure curves recorded during previous valvuloplasty procedures. Our experimental and clinicopathological observations showed that the degree of obstruction of the aortic orifice in post-mortem specimens and the tolerance to balloon inflation in live patients are dependent of the valvular configuration. Although trefoil balloons have the theoretical advantage to avoid complete obstruction of the aortic orifice during inflation, we observed that in presence of a tricuspid configuration, they could be potentially more occlusive than monofoil balloons since each of the 3 individual components of the trefoil balloon occupied the intercommissural spaces while inflated. However, they offered more residual free space when inflated in aortic valves with a bicuspid configuration (i.e. congenitally bicuspid valves or tricuspid valves with one fused commissure). In our opinion, these observations are relevant, since degenerative disease of the aortic valve (i.e. tricuspid valve without commissural fusion) is now recognized as the most common etiology of aortic stenosis in the elderly.

[Chronology and incidence of restenosis after coronary angioplasty. Comparison of patients with stable and unstable angina]

The aim of this prospective study was to compare the incidence of restenosis after percutaneous transluminal coronary angioplasty (PTCA) in patients with stable and unstable angina before the procedure. Between January 1984 and February 1986, 344 patients with stable angina and 228 patients with unstable angina underwent PTCA. The primary success rate was 86.3 per cent in patients with stable angina (297 patients) and 87.7 per cent in patients with unstable angina (200 patients). The patients were recalled for systematic control coronary arteriography at 30, 60, 90, 120 or 150 days, and was obtained in 83.8 per cent of patients with stable angina and in 86 per cent of patients with unstable angina. The degree of stenosis before and the angiographic changes after PTCA and at control coronary arteriography were evaluated by a computer-assisted automatic contour detection system. The three criteria of restenosis were: 1) over 50 per cent loss of the benefit of PTCA, 2) residual post-PTCA stenosis increasing from less than 50 per cent to more than 50 per cent at control arteriography, 3) a decrease in the minimum intraluminal diameter of at least 0.72 mm with respect to the immediate post-PTCA result. A comparison between the two groups of patients showed that the average age was slightly greater in patients with unstable angina (56 +/- 9 years vs 58 +/- 9 years, p = 0.047). Apart from this difference, the two groups were comparable with regards to the average number of lesions dilated per patient, the date of control arteriography, the severity of the coronary artery disease and previous bypass surgery, angioplasty and infarction.(ABSTRACT TRUNCATED AT 250 WORDS)

Assessment of the "long sheath" technique for percutaneous aortic balloon valvuloplasty

A 100 cm-long 16.5 F valvuloplasty catheter introducer was assessed as an adjunct for percutaneous transluminal aortic valvuloplasty (PTAV) via the femoral artery in 31 patients with severe aortic stenosis. Observed improvements in peak systolic gradient (81.6 +/- 29.9 mm Hg vs. 35.5 +/- 16.0 mm Hg, P less than 0.000001) and aortic valve area (0.6 +/- 0.4 cm2 vs. 1.0 +/- 0.6 cm2, P less than 0.00001) were similar to those achieved in a control group (C) of 17 patients in which no femoral sheath was used. However, a shorter procedure duration (211 +/- 81 min vs. 117 +/- 30 min, P less than 0.001) and a reduced rate of vascular complications at the femoral puncture site (41% vs. 6.5%) were observed in patients in whom the long sheath (LS) technique was used. The frequency of other PTAV-related complications was comparable (C = 35%, LS = 29%, P = n.s.). Other technical advantages of this device are: 1) prevention of looping and bending of the balloon catheter in tortuous vessels and easy positioning of the balloon across the aortic orifice provided by the LS trackability, 2) stabilisation of the balloon during inflation, 3) monitoring of supravalvular aortic pressure provided by the side-arm of the LS and reliable measurement of systolic gradient, and 4) the ability to perform aortograms without the need of another catheter in the ascending aorta. Thus, in our experience, the long sheath technique is a valuable adjunct for PTAV.