End-of-trial inflammatory biomarkers, lipid levels, creatine kinase and markers of renal and liver function in the LoDoCo2 trial

Background

The Low-Dose Colchicine 2 (LoDoCo2) trial demonstrated that colchicine reduced major cardiovascular events in patients with chronic coronary artery disease (CAD). The effect of long-term colchicine treatment on inflammatory biomarkers and markers reflecting renal and liver function have not been investigated yet.

Purpose

This substudy examines levels of inflammatory biomarkers, lipid fractions, creatine kinase (CK) and markers of renal and liver function at close-out of the trial.

Methods

The LoDoCo2 trial randomly assigned patients with chronic CAD to colchicine 0.5 mg once daily or placebo. Blood samples were drawn during close-out visits after a median follow-up of 32.7 (interquartile range [IQR] 24.0–48.6) months.

Results

Assignment to colchicine was associated with lower levels of high-sensitivity C-Reactive Protein (0.94 mg/L [0.53–1.93] vs. 1.24 mg/L [0.73–2.55]; −24.2%; p<0.01) and interleukin-6 (2.70 ng/L [1.79–4.18] vs. 3.16 ng/L [2.07–4.95]; −14.9%; p<0.01), but was not associated with any differences in lipid fractions or markers of renal function. Although CK levels were higher after colchicine (123.0 U/L, [84.0–184.0] vs. 110.0 U/L, [77.0–164.0], p<0.01), the number of participants with marked elevations of CK (>5 times upper limit of normal [ULN]) was low and not different between treatment groups. Levels of alanine aminotransferase (ULN 40 U/L) and albumin (ULN 50 U/L) were higher (p<0.01) in the colchicine group compared to placebo (30.0 U/L [22.0–40.0] vs. 26.0 U/L [19.0–34.0] and 43.01 g/L±2.39 vs. 42.64 g/L±2.48, respectively). There were no differences in gamma-glutamyl transferase or bilirubin.

Conclusion

Long-term low-dose colchicine in patients with chronic CAD was associated with lower levels of hs-CRP and IL-6 but was not associated with clinically important differences in lipid fractions, CK, renal or liver function.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): The National Health Medical Research Council of AustraliaThe Netherlands Organization for Health Research and Development

The effects of colchicine in patients with diabetes mellitus and chronic coronary artery disease: a post-hoc analysis of the LoDoCo2-trial

Background

Atherosclerosis is an inflammatory disease and is accelerated by diabetes mellitus (DM). Patients with chronic coronary artery disease (CAD) who also have DM are at high risk of recurrent cardiovascular events. The role of inflammation in atherosclerosis is well established, whereas the role of inflammation on incident and progression of DM has been hypothesized. The nucleotide-binding oligomerization domain-, leucine-rich repeat-, and pyrin domain-containing protein 3 (NLRP3) inflammasome in particular, may play an important role in the onset and progression of T2DM. The anti-inflammatory drug colchicine attenuates the NLRP3-inflammasome. The Low-Dose Colchicine 2 (LoDoCo2) trial showed that colchicine reduces cardiovascular risk in patients with chronic CAD.

Purpose

The purpose of this study was to assess the effects of colchicine in patients with chronic CAD and DM on cardiovascular events as well as the effect of colchicine on the development of new-onset DM.

Methods

The LoDoCo2 trial randomized 5522 to placebo or colchicine, with a median follow-up of 28.6 months (interquartile range 20.5–44.4). The primary endpoint was a composite of cardiovascular death, spontaneous myocardial infarction, ischaemic stroke, or ischaemia-driven revascularization. Secondary outcomes consisted of the aforementioned events, separately. Cox proportional hazards models were used to investigate univariable associations between DM status for all endpoints in the placebo group. The interactions between treatment group and DM status were evaluated with the addition of treatment and the treatment-by-DM variable interaction.

Results

In total, 1007 participants (18.2%) had DM at baseline. The hazard ratio for the primary endpoint was 0.87 (95% CI, 0.61–1.25) in those with DM and 0.64 (95% CI, 0.51–0.80) in those without DM (p for interaction>0.05). Treatment effects of colchicine were consistent over all secondary endpoints (p for interaction>0.05). The incidence of new-onset DM was 1.5% (34/2270) in the colchicine group and 2.2% (49/2245) in the placebo group (p=0.10). Participants with DM were at higher risk for all endpoints. The primary composite end point in the placebo group occurred in 13.0% (67/515) patients with DM and in 8.8% (197/2245) of the patients without DM (unadjusted hazard ratio 1.54 [95% CI 1.16–2.03, p<0.01]) compared to the group without DM. DM was also strongly associated with the occurrence of all secondary end points.

Conclusion

This study shows that the beneficial effects of colchicine on cardiovascular endpoints are consistent regardless of DM status. The data indicate that larger trials are needed to assess whether colchicine reduces the incidence of new-onset DM.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): National Health Medical Research Council of Australia and the Netherlands Organization for Health Research and Development

Calcaneal quantitative ultrasound is associated with all-cause and cardiovascular disease mortality independent of hip bone mineral density

Osteoporosis has been linked with increased risk of cardiovascular disease previously. However, few studies have detailed bone and vascular information. In a prospective study of older women, we demonstrated heel quantitative ultrasound measures were associated with increased cardiovascular and all-cause mortality, independent of established cardiovascular risk factors.

INTRODUCTION

Osteoporosis and low bone mineral density (BMD) have been previously linked to cardiovascular disease (CVD) and mortality. Calcaneal quantitative ultrasound (QUS) is used to evaluate bone material properties, especially in older women. However, it is uncertain whether it is related to risk of mortality. This study was aimed to investigate the association between calcaneal QUS measurements and 15-year all-cause and CVD mortality in 1404 older women (mean age 75.2 ± 2.7 years).

METHODS

One thousand four hundred four older women, participants of Calcium Intake Fracture Outcome study (CAIFOS), had calcaneal bone measured at baseline (1998) and followed for 15 years. The primary outcomes, any deaths, and deaths attributable to cardiovascular causes ascertained by using linked data were obtained from Western Australia data linkage system.

RESULTS

Over the 15 years of follow-up (17,955 person years), 584 of the women died, and 223 from CVD. For every standard deviation (SD), reduction in broadband ultrasound attenuation (BUA) in minimally and multivariable-adjusted model including cardiovascular risk factors increased relative hazards for all-cause (multivariable-adjusted HR 1.15; 95%CI: 1.06-1.26, p = 0.001) and CVD mortality (multivariable-adjusted HR 1.20; 95%CI: 1.04-1.38, p = 0.010). Such relationships also persisted when hip BMD was included in the model (all-cause mortality HR 1.19; 95%CI: 1.07-1.33, p = 0.002; CVD mortality HR 1.28; 95%CI: 1.07-1.53, p = 0.008).

CONCLUSION

BUA is associated with all-cause and CVD mortality in older women independent of BMD and established CVD risk factors. Understanding why and how these are related may provide further insights about the bone-vascular nexus as well as therapeutic targets benefiting both systems.

Common genetic variants do not predict recurrent events in coronary heart disease patients

Background

It is unclear whether genetic variants identified from single nucleotide polymorphisms (SNPs) strongly associated with coronary heart disease (CHD) in genome-wide association studies (GWAS), or a genetic risk score (GRS) derived from them, can help stratify risk of recurrent events in patients with CHD.

Methods

Study subjects were enrolled at the close-out of the LIPID randomised controlled trial of pravastatin vs placebo. Entry to the trial had required a history of acute coronary syndrome 3–36 months previously, and patients were in the trial for a mean of 36 months. Patients who consented to a blood sample were genotyped with a custom designed array chip with SNPs chosen from known CHD-associated loci identified in previous GWAS. We evaluated outcomes in these patients over the following 10 years.

Results

Over the 10-year follow-up of the cohort of 4932 patients, 1558 deaths, 898 cardiovascular deaths, 727 CHD deaths and 375 cancer deaths occurred. There were no significant associations between individual SNPs and outcomes before or after adjustment for confounding variables and for multiple testing. A previously validated 27 SNP GRS derived from SNPs with the strongest associations with CHD also did not show any independent association with recurrent major cardiovascular events.

Conclusions

Genetic variants based on individual single nucleotide polymorphisms strongly associated with coronary heart disease in genome wide association studies or an abbreviated genetic risk score derived from them did not help risk profiling in this well-characterised cohort with 10-year follow-up. Other approaches will be needed to incorporate genetic profiling into clinically relevant stratification of long-term risk of recurrent events in CHD patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-022-02520-0.

12-month post-trial follow-up of participants in the Australian arm of the second low-dose colchicine trial

Background

In the Australian arm of the LoDoCo2 trial, colchicine 0.5mg daily compared with placebo markedly reduced the risk of cardiovascular (CV) events in patients with chronic coronary disease (2.0 vs 3.9 events per 100 person years, HR 0.51; 95% CI 0.39–0.67). The purpose of this analysis was to explore CV and non-CV outcomes in the Australian cohort out to one year after cessation of trial medication.

Methods

Information was collected on all potential CV events and non-CV deaths as well as a range of other co-morbidities. All CV events were blindly adjudicated. The analysis examined the primary outcome (a composite of CV death, myocardial infarction, ischemic stroke, and unscheduled revascularization) and non-CV deaths by initial randomized treatment from the beginning of the trial up until one year after cessation of trial medication. A landmark analysis was then used to examine these outcomes from the date of last contact during the trial until one year after cessation of trial medication.

Results

The clinical status was confirmed in 1819/1824 (99.7%) participants who were alive at the end of the trial, and in 100% of those participants still taking trial medication at the end of the trial. During post-trial follow up, 515 patients (28.2%) were taking non-study colchicine, including 278 (30.5%) originally randomized to colchicine and 237 (25.9%) randomized to placebo. Over the entire follow-up period that included the 12-month period after the trial medication was ceased, the effect of prior exposure to colchicine on the primary CV outcome was still evident (2.2 vs 3.8 events per 100 person years, HR 0.58; 95% CI 0.45–0.74), however no post-trial CV benefit were apparent in the landmark analysis (3.3 vs 3.4 events per 100 person years, HR 0.97; 95% CI 0.56–0.1.69). Over the entire course of follow-up the incidence of new cancer (7.9% vs 7.2% RR 0.91; 95% CI 0.66–1.25) and non-CV death (0.9 vs 0.6 events per 100 person years, HR 1.44; 95% CI 0.92–2.27) was no different in the treatment groups.

Conclusion

Although the CV benefits of colchicine treatment that emerged during the trial were still evident in the year after stopping study treatment, no additional CV benefit accrued after it was ceased. These data suggest that colchicine should be continued long-term to maximize its CV benefits.

Funding Acknowledgement

Type of funding sources: None.

Changing patterns of medical treatment in acute myocardial infarction

TYPE OF STUDY

Descriptive study of trends in the drug therapy for acute myocardial infarction.

SETTING

Population-based register of acute coronary events compiled for the years 1984 to 1990 in the course of the Perth MONICA project.

CASES

5294 cases meeting clinical criteria for acute myocardial infarction.

RESULTS

Striking changes were seen in the use of aspirin before admission to hospital (from 4% to 18%). During the stay in hospital the use of beta-blockers increased steadily from 52% to 76%, while the use of aspirin increased 3.5-fold from 25% to 88% and the use of streptokinase increased 13.5-fold from 2.4% to 32.4%. The proportion of patients prescribed beta-blockers on discharge from hospital increased from 46% to 65% and that for aspirin rose from 16% to 83%. There were also major relative increases in the use of lipid-lowering agents and declines in the use of antiarrhythmic drugs.

CONCLUSION

These trends in the pharmacological management of myocardial infarction mirror the emerging evidence from clinical trials, although the increases in the use of certain types of drugs antedated publication of the results of major randomised studies. The changes in therapy would partly explain observed improvements in case fatality and may have contributed to the decline in coronary mortality observed in the Perth community.

Follow‐up care after acute myocardial infarction

OBJECTIVE

To examine the medical care received by patients following discharge from hospital after acute myocardial infarction (AMI).

SETTING AND DESIGN

Community-based cross-sectional survey.

PATIENTS

2836 consecutive patients aged 25-64 years living in the Perth Statistical Division who were admitted to hospital with AMI during 1984-1988. After one reminder the response rate was 71%.

RESULTS

Half of all respondents were in full-time employment at the time of their AMI. At follow-up this had fallen to a third. Over 80% of patients visited a cardiologist after AMI, with half remaining under consultant care to the time of survey. However, one in five patients reported no follow-up care at the time of survey. Seventy-three per cent of patients reported undergoing at least one exercise stress test after AMI, with 61% undergoing angiography, 16% angioplasty and 24% coronary bypass surgery. Large proportions of the patients accurately reported being prescribed beta-blockers and antiplatelet agents. The pattern of prescribing at discharge corresponded closely with the use of cardioactive agents at the time of survey and with drugs reported to have been taken continuously since discharge to the time of survey.

CONCLUSIONS

These data suggest that follow-up care after AMI is both comprehensive and widespread. Such care may have contributed significantly to the overall decline in mortality from ischaemic heart disease.

Evidence-based prescribing of drugs for secondary prevention of acute coronary syndrome in Aboriginal and non-Aboriginal patients admitted to Western Australian hospitals

AIMS

To assess the level of evidence-based drug prescribing for acute coronary syndrome (ACS) at discharge from Western Australian (WA) hospitals and determine predictors of such prescribing in Aboriginal and non-Aboriginal patients.

METHODS

All Aboriginal (2002-2004) and a random sample of non-Aboriginal (2003) hospital admissions with a principal diagnosis of ACS were extracted from the WA Hospital Morbidity Data Collection of WA Data Linkage System. Clinical information, history of co-morbidities and drugs were collected from medical notes by trained data collectors. Evidence-based prescribing (EBP) was defined as prescribing of aspirin, statin and beta-blocker or angiotensin-converting enzyme inhibitor/angiotensin II antagonist.

RESULTS

Records for 1717 ACS patients discharged alive from hospitals were reviewed. The majority of patients (71%) had EBP, and there was no significant difference between Aboriginal and non-Aboriginal patients (70% vs 71%, P = 0.36). Conversely, a significantly higher proportion of Aboriginal patients had none of the drugs prescribed compared with non-Aboriginal patients (11% vs 7%, P < 0.01). EBP for ACS was independently associated with male sex (odds ratio (OR) 1.63, 95% confidence interval (CI) 1.26-2.11), previous admission for ACS (OR 1.83, 95% CI 1.39-2.42) and diabetes (OR 1.36, 95% CI 1.04-1.79). However, ACS patients living in regional and remote areas, attending district or private hospitals, or with a history of chronic obstructive pulmonary disease were significantly less likely to have ACS drugs prescribed at discharge.

CONCLUSIONS

Opportunity exists to improve prescribing of recommended drugs for ACS patients at discharge from WA hospitals in both Aboriginal and non-Aboriginal patients. Attention regarding pharmaceutical management post-ACS is particularly required for patients from rural and remote areas, and those attending district and private hospitals.

The effect of yoghurt and its probiotics on blood pressure and serum lipid profile; a randomised controlled trial

BACKGROUND AND AIMS

Despite strong mechanistic data, and promising results from in vitro and animal studies, the ability of probiotic bacteria to improve blood pressure and serum lipid concentrations in humans remains uncertain. The aim of this study was to determine the effect of Lactobacillus acidophilus La5 and Bifidobacterium animalis subsp lactis Bb12, provided in either yoghurt or capsule form, on home blood pressure and serum lipid profile.

METHODS AND RESULTS

Following a 3-week washout period, 156 overweight men and women over 55 y were randomized to a 6-week double-blinded, factorial, parallel study. The four intervention groups were: A) probiotic yoghurt plus probiotic capsules; B) probiotic yoghurt plus placebo capsules; C) control milk plus probiotic capsules; and D) control milk plus placebo capsules. Each probiotic test article provided a minimum L. acidophilus La5 and B. animalis subsp. lactis Bb12 dose of 3.0 × 10⁹ CFU/d. Home blood pressure monitoring, consisting of 7-day bi-daily repeat measurements, were collected at baseline and week 6. Fasting total cholesterol, low density lipoprotein cholesterol (LDLC), high density lipoprotein cholesterol (HDLC), and serum triglyceride were performed at baseline and week 6. When compared to control milk, probiotic yoghurt did not significantly alter blood pressure, heart rate or serum lipid concentrations (P > 0.05). Similarly, when compared to placebo capsules, supplementation with probiotic capsules did not alter blood pressure or concentrations of total cholesterol LDLC, HDLC, or triglycerides (P > 0.05).

CONCLUSIONS

The probiotic strains L. acidophilus La5 and B. animalis subsp. lactis Bb12 did not improve cardiovascular risk factors.

Changes in clinical indications for community antibiotic prescribing for children in the UK from 1996 to 2006: will the new NICE prescribing guidance on upper respiratory tract infections just be ignored?

OBJECTIVE

To analyse changes in clinical indications for community antibiotic prescribing for children in the UK between 1996 and 2006 and relate these findings to the new NICE guidelines for the treatment of upper respiratory tract infections in children.

STUDY DESIGN

Retrospective cohort study.

METHOD

The IMS Health Mediplus database was used to obtain annual antibiotic prescribing rates and associated clinical indications in 0-18-year-old patients between 1 January 1996 and 31 December 2006 in the UK.

RESULTS

Antibiotic prescribing declined by 24% between 1996 and 2000 but increased again by 10% during 2003-2006. Respiratory tract infection was the most common indication for which an antibiotic was prescribed, followed by "abnormal signs and symptoms", ear and skin infections. Antibiotic prescriptions for respiratory tract infections have decreased by 31% (p<0.01) mainly because of reduced prescribing for lower respiratory tract infections (56% decline, p<0.001) and specific upper respiratory tract infections including tonsillitis/pharyngitis (48% decline, p<0.001) and otitis (46% decline, p<0.001). Prescribing for non-specific upper respiratory tract infection increased fourfold (p<0.001). Prescribing for "abnormal signs and symptoms" increased significantly since 2001 (40% increase, p<0.001).

CONCLUSION

There has been a marked decrease in community antibiotic prescribing linked to lower respiratory tract infection, tonsillitis, pharyngitis and otitis. Overall prescribing is now increasing again but is associated with non-specific upper respiratory tract infection diagnoses. General practitioners may be avoiding using diagnoses where formal guidance suggests antibiotic prescribing is not indicated. The new NICE guidance on upper respiratory tract infections is at risk of being ignored.

Long term survival after evidence based treatment of acute myocardial infarction and revascularisation: follow-up of population based Perth MONICA cohort, 1984-2005

OBJECTIVE

To examine trends in long term survival in patients alive 28 days after myocardial infarction and the impact of evidence based medical treatments and coronary revascularisation during or near the event.

DESIGN

Population based cohort with 12 year follow-up.

SETTING

Perth, Australia.

PARTICIPANTS

4451 consecutive patients with a definite acute myocardial infarction according to the World Health Organization MONICA (monitoring trends and determinants in cardiovascular disease) criteria admitted to hospital during 1984-7, 1988-90, and 1991-3.

MAIN OUTCOME MEASURES

All cause mortality identified from official mortality records and the hospital morbidity data, with death from cardiovascular disease as a secondary end point.

RESULTS

In the 1991-3 cohort, 28 day survivors of acute myocardial infarction had a 7.6% absolute event reduction (95% confidence interval 4% to 11%) or a 28% lower relative risk reduction (16% to 38%), unadjusted for risk of death, over 12 years after the incident admission compared with the 1984-7 cohort, similar to the survival of the 1988-90 cohort. The improved survival for the 1991-3 cohort persisted after adjustment for demographic factors, coronary risk factors, severity of disease, and event complications with an adjusted relative risk reduction of 26% (14% to 37%), but this was not apparent after further adjustment for medical treatments in hospital and coronary revascularisation procedures within 12 months of the incident myocardial infarction.

CONCLUSION

The improving trends in 12 year survival after a definite acute myocardial infarction are associated with progressive use of evidence based treatments during the initial admission to hospital and in the 12 months after the event. These changes in the management of acute myocardial infarction are probably contributing to the continuing decline in mortality from coronary heart disease in Australia.

Has UK guidance affected general practitioner antibiotic prescribing for otitis media in children?

BACKGROUND

Since 1997, UK guidance has advocated limiting antibiotic prescribing for otitis media. It is not known whether this has influenced general practitioner prescribing practice. Aims and objectives To investigate the trends in diagnoses and antibiotic prescribing for otitis media in children in relation to guidance.

METHODS

We used the General Practice Research Database to conduct time-trend analyses of diagnoses and antibiotic prescribing for otitis media in 3 months to 15 years old, between 1990 and 2006.

RESULTS

A total of 1 210 237 otitis media episodes were identified in 464 845 children; two-thirds (68%; 818 006) received antibiotics. Twenty-two percent (267 335) were classified as acute, 85% (227 335) of which received antibiotics. Overall, antibiotic prescribing for otitis media declined by 51% between 1995 and 2000. Much of this reduction predated guidance. During this period, prescribing for otitis media coded as acute increased by 22%. Children diagnosed with acute otitis media were more likely to receive antibiotics than otitis media not coded as acute (P < 0.05). From 2000 prescribing plateaued, despite publication of further guidance. Otitis media diagnoses consistently paralleled prescribing.

CONCLUSIONS

The reduction in antibiotic prescribing for otitis media predated guidance. The simultaneous decrease in prescribing for non-acute otitis media and increase for acute otitis media suggest diagnostic transfer, possibly to justify the decision to treat.

The C-480T hepatic lipase polymorphism is associated with HDL-C but not with risk of coronary heart disease

High-density lipoprotein cholesterol (HDL-C) is a known predictor of coronary heart disease (CHD). Studies have shown that the C-480T polymorphism of the hepatic lipase (HL) gene is predictive of HDL-C; however, its observed relationship with the risk of CHD has been inconsistent. We analysed four biallelic polymorphisms in the HL gene in participants from three independent Western Australian populations. Samples were collected from two cross-sectional studies of 1111 and 4822 community-based subjects assessed for cardiovascular risk factors, and a third sample of 556 subjects with physician-diagnosed CHD. Genotypes were tested for association with plasma lipids and the risk of CHD. All polymorphisms were highly correlated (D' > 0.97, r(2) > 0.90); therefore, only C-480T was analysed. The -480T allele was significantly associated with an increase in HDL-C of between 0.08 and 0.16 mmol/l in all three populations (p < 0.001). No associations with other lipids were observed, nor was an association with CHD in a case-control study of males. The TT genotype was however associated with decreased risk of myocardial infarction among cases (odds ratio = 0.39, 95% confidence interval = 0.19-0.78, p = 0.008). These findings replicate those of previous studies in three independent populations and suggest that the genetic determinants of CHD are complex and cannot be entirely explained through intermediate phenotypes.

Failure of current public educational campaigns to impact on the initial response of patients with possible heart attack

AIMS

The National Heart Foundation of Australia recognizes that the risk of lethal arrhythmias is greater very early after the onset of myocardial infarction and that the more promptly flow can be restored in the infarct-related artery the greater will be the benefits for survival and preservation of heart function. The Heart Foundation has therefore conducted several public media campaigns to encourage patients to seek help more promptly and evaluated their impact.

METHODS

Since 1996, we have conducted four surveys of delays preceding admission of patients to coronary care units throughout Australia to assess the impact of the Heart Foundation's media campaigns. Data were collected on 1665 patients who presented to 73 hospitals; information on patient delay was available for 1178 of them.

RESULTS

There were no significant differences in patient delay (median 1.5-2.0 h) in the four surveys from 1996 to 2002, nor when patients were categorized by age, sex, presenting diagnosis or history of previous myocardial infarction or coronary revascularization by percutaneous or surgical techniques.

CONCLUSION

New approaches are needed to reduce patient-related delay after the onset of symptoms suggesting possible myocardial infarction.

Mortality and recurrent cardiac events after coronary artery bypass graft: long term outcomes in a population study

OBJECTIVE

To determine 30 day mortality, long term survival, and recurrent cardiac events after coronary artery bypass graft (CABG) in a population.

DESIGN

Follow up study of patients prospectively entered on to a cardiothoracic surgical database. Record linkages were used to obtain data on readmissions and deaths.

PATIENTS

8910 patients undergoing isolated first CABG between 1980 and 1993 in Western Australia.

MAIN OUTCOME MEASURES

30 day and long term survival, readmission for cardiac event (acute myocardial infarction, unstable angina, percutaneous transluminal coronary angioplasty or reoperative CABG).

RESULTS

There were 3072 deaths to mid 1999. 30 day and long term survival were significantly better in patients treated in the first five years than during the following decade. The age of the patients, proportion of female patients, and number of grafts increased over time. An urgent procedure (odds ratio 3.3), older age (9% per year) and female sex (odds ratio 1.5) were associated with increased risk for 30 day mortality, while age (7% per year) and a recent myocardial infarction (odds ratio 1.16) influenced long term survival. Internal mammary artery grafts were followed by better short and long term survival, though there was an obvious selection bias in favour of younger male patients.

CONCLUSIONS

This study shows worsening crude mortality at 30 days after CABG from the mid 1980s, associated with the inclusion of higher risk patients. Older age, an acute myocardial infarction in the year before surgery, and the use of sephenous vein grafts only were associated with poorer long term survival and greater risk of a recurrent cardiac event. Female sex predicted recurrent events but not long term survival.

Antioxidant vitamins and the risk of carotid atherosclerosis. The Perth Carotid Ultrasound Disease Assessment study (CUDAS)

OBJECTIVES

This study examined whether dietary intake or plasma levels of antioxidant vitamins were independently associated with common carotid artery intima-media (wall) thickness (IMT) or focal plaque, or both, in a large, randomly selected community population.

BACKGROUND

Oxidation of low-density lipoprotein (LDL) cholesterol is thought to be important in early atherogenesis. Antioxidant micronutrients may therefore protect against lipid peroxidation and atherosclerotic vascular disease.

METHODS

We studied 1,111 subjects (558 men and 553 women; age 52 +/- 13 years [mean +/- SD], range 27 to 77). We measured dietary vitamin intake and fasting plasma levels of vitamins A, C and E, lycopene and alpha- and beta-carotene and performed bilateral carotid artery B-mode ultrasound imaging. RESULTS; After adjustment for age and conventional risk factors, there was a progressive decrease in mean IMT, with increasing quartiles of dietary vitamin E intake in men (p = 0.02) and a nonsignificant trend in women (p = 0.10). Dietary vitamin E levels accounted for 1% of the variance in measured IMT in men. For plasma antioxidant vitamins, there was an inverse association between carotid artery mean IMT and plasma lycopene in women (p = 0.047), but not in men. None of the other dietary or plasma antioxidant vitamins, nor antioxidant vitamin supplements, were associated with carotid artery IMT or focal carotid artery plaque.

CONCLUSIONS

This study provides limited support for the hypothesis that increased dietary intake of vitamin E and increased plasma lycopene may decrease the risk of atherosclerosis. No benefit was demonstrated for supplemental antioxidant vitamin use.

Polymorphisms in the angiotensinogen gene are associated with carotid intimal-medial thickening in females from a community-based population

BACKGROUND

Polymorphisms within genes of the renin-angiotensin system have been associated with an increased risk of cardiovascular disease. We investigated the association of polymorphisms in the angiotensinogen (AGT) and angiotensin II receptor type 1 (AGTR1) genes with increased intima-media thickness (IMT) and the presence of plaques in carotid arteries.

METHODS

Subjects (1111) from the Perth Carotid Ultrasound Disease Assessment Study (CUDAS) were genotyped for three polymorphisms: two in the promoter of the AGT gene, G-6A and A-20C; and one in the AGTR1 gene, A1166C.

RESULTS

Using multivariate generalised linear models, the AGT-6A allele (P<0.001) and the AGT-20C allele (P<0.03) were significantly associated with increased mean carotid IMT in females but not in males when adjusted for conventional risk factors. The AGTR1 A1166C polymorphism did not show any significant relationship to mean IMT. Results suggest that the I allele of the angiotensin converting enzyme insertion/deletion polymorphism may interact with the AGT-6G allele to increase mean carotid IMT in the population as a whole. None of the polymorphisms investigated were significantly associated with the presence of carotid plaques.

CONCLUSION

This study shows that polymorphisms in the angiotensinogen gene are associated with an increased risk of carotid intimal-medial wall thickening in females.

Role of coronary interventional procedures in improved postinfarction survival in the 1990s

The contribution of increased use of same-admission percutaneous coronary interventional procedures to recent improvements in hospital survival of patients with acute myocardial infarction (AMI) remains unclear. Patients with International Classification of Diseases codes for AMI (code 410), who were admitted to the emergency coronary care unit and underwent an initial episode of treatment, were studied over the 9-year period 1990 to 1998 (n = 2,628). Three triennia between 1990 and 1998 were compared. Trends in risk, the use of procedures, and hospital outcomes were analyzed. Hospital mortality was 33% lower (p <0.02) in the third triennium (5.8%) than in the earlier 2 triennia (8.7%), equivalent to an absolute reduction of 29 hospital deaths/1,000 patients treated. The lower hospital mortality was not due to: (1) shorter hospital stays (reduction in mortality was primarily in the first 3 hospital days), (2) treatment of lower risk subjects (a risk score based on age, gender, and presence of diabetes increased between the first and third triennia), or (3) use of in-hospital interventional procedures (although the use of percutaneous coronary intervention more than doubled in the third triennium, most procedures were performed in patients with a 1% risk of hospital death). We conclude from this study that there has been a substantial improvement over a 9-year period in early case fatality after AMI, but that this cannot be attributed to the increased use of in-hospital coronary interventions, which were largely performed on low-risk patients.

A Pro12Ala polymorphism in the human peroxisome proliferator-activated receptor-gamma 2 is associated with combined hyperlipidaemia in obesity

OBJECTIVE

Peroxisome proliferator-activated receptor-gamma 2 (PPAR gamma 2) is an important regulator of adipose tissue metabolism and insulin sensitivity. The aim of this investigation was to determine whether a PPAR gamma 2 Pro12Ala polymorphism was associated with cardiovascular risk factors (obesity, blood pressure, diabetes and blood lipids) in Western Australian Caucasians (n=663).

DESIGN

Subjects were selected from two population studies (the Carotid Ultrasound Disease Assessment Study (CUDAS) and Busselton Population Health Survey) on the basis of body mass index (BMI). 292 obese (BMI > or =30 kg/m) and 371 lean (BMI <25 kg /m) subjects were studied.

METHODS

Blood pressure and anthropometric measurements were collected from all participants, as well as a fasting venous blood sample. Biochemical measurements (high-density lipoprotein (HDL)- and low-density lipoprotein-cholesterol, triglycerides) and PPAR gamma 2 Pro12Ala genotype were also determined.

RESULTS

Obese Pro/Ala and Ala/Ala subjects had lower levels of HDL-cholesterol (P=0.032) and a trend towards higher levels of triglycerides (P=0.055) compared with obese Pro/Pro subjects. In the obese group, the Ala allele was significantly associated with the presence of combined hyperlipidaemia (odds ratio = 2.33, P=0.042). There was no significant difference in the frequency of the polymorphism between lean and obese groups (P=0.069). No association was observed between Pro12Ala genotype and obesity, blood pressure or diabetes in either group.

CONCLUSIONS

Obese carriers of the Pro12Ala polymorphism have a greater risk of developing combined hyperlipidaemia, possibly due to impaired activation of PPAR gamma target genes. The Pro12Ala polymorphism is not directly associated with obesity, hypertension or diabetes in this population.

Clinical relevance of statins: instituting treatment early in acute coronary syndrome patients

The efficacy of statins in lowering the total and low-density lipoprotein cholesterol and reducing the risk of cardiac events is now well established. The secondary prevention studies started treatment several months after the acute event. However, the greatest risk of recurrence is shortly after the index event. Recent evidence from small-scale clinical trials shows that standard doses of statins can be both safe and effective when given early after an acute coronary event, including early after thrombolytic therapy for myocardial infarction. Angiographic studies have shown beneficial effects of pravastatin on coronary stenosis when initiated after a coronary event. While none of these studies have been powered to demonstrate an effect on outcome, each has shown a reduction in major cardiovascular events. Two large observational studies have shown a reduction in 6- and 12-month risk-adjusted mortality among post-MI patients treated early with statins. Large-scale trials of all statins are now in progress to evaluate further the efficacy of early initiation of statin therapy in acute coronary syndromes. The largest of these is the Australian Pravastatin Acute Coronary Treatment (PACT) study, which will compare early outcomes in patients treated with pravastatin versus placebo prescribed within the first 24 h of an acute coronary event.

Grazing-incidence hyperboloid-hyperboloid designs for wide-field x-ray imaging applications

The classical Wolter type I grazing-incidence x-ray telescope consists of a paraboloidal primary mirror and a confocal hyperboloidal secondary mirror. This design exhibits stigmatic imaging on-axis but suffers from coma, astigmatism, field curvature, and higher-order aberrations such as oblique spherical aberration. Wolter-Schwarzschild designs have been developed that strictly satisfy the Abbe sine condition and thus exhibit no spherical aberration or coma. However, for wide-field applications such as the solar x-ray imager (SXI), there is little merit in a design with stigmatic imaging on-axis. Instead, one needs to optimize some area-weighted-average measure of resolution over the desired operational field of view. This has traditionally been accomplished by mere despacing of the focal plane of the classical Wolter type I telescope. Here we present and evaluate in detail a family of hyperboloid-hyperboloid grazing-incidence x-ray telescope designs whose wide-field performance is much improved over that of an optimally despaced Wolter type I and even somewhat improved over that of an optimally despaced Wolter-Schwarzschild design.

Effects of pravastatin in 3260 patients with unstable angina: results from the LIPID study

BACKGROUND

The LIPID study is a major trial of secondary prevention of coronary-heart-disease events that includes hospital admission with unstable angina (as well as myocardial infarction) as a qualifying event. In this substudy of LIPID, we compared subsequent cardiovascular risks and the effects of pravastatin in patients with previous unstable angina or previous myocardial infarction.

METHODS

3260 patients diagnosed with unstable angina and 5754 with acute myocardial infarction 3-36 months previously were randomly assigned 40 mg pravastatin daily or placebo over a mean of 6.0 years. The risk reduction of a range of cardiovascular events was estimated by means of the hazard ratio in Cox's proportional hazards model.

FINDINGS

Among patients assigned placebo, survival in the two diagnosis groups was similar. The relative risk reduction for mortality with pravastatin was 20.6% in the myocardial infarction group and 26.3% in the unstable angina group (p=0.55). Pravastatin significantly reduced the rates of all prespecified coronary endpoints in the myocardial infarction group. In patients with previous unstable angina, coronary heart disease mortality, total mortality, myocardial infarction, a need for coronary revascularisation, the number of admissions to hospital, and the number of days in hospital were significantly lower with pravastatin. Overall, hospital admission for unstable angina was the most common endpoint (24.6% of the placebo group; 22.3% of the pravastatin group).

INTERPRETATION

Patients who have survived acute myocardial infarction or unstable angina have a similar long-term prognosis, a high occurrence of subsequent unstable angina, and benefit similarly from therapy with pravastatin.

Serum ferritin and C282Y mutation of the hemochromatosis gene as predictors of asymptomatic carotid atherosclerosis in a community population

BACKGROUND AND PURPOSE

Serum ferritin and heterozygosity for the C282Y mutation of the hemochromatosis gene have both been associated with an increased risk of cardiovascular events. The purpose of the study was to test whether either is a risk predictor for asymptomatic carotid atherosclerosis.

METHODS

We assessed carotid intima-media wall thickness (IMT) and focal plaque formation by high-resolution B-mode ultrasound, conventional risk factors, serum ferritin levels, and the C282Y mutation of the hemochromatosis gene in a randomly selected community population of 1098 subjects (545 women and 553 men) aged 27 to 77 years.

RESULTS

After adjustment for conventional risk factors, serum ferritin was not associated with carotid mean IMT. Women with ferritin values over the first quartile (>34 microg/L) had an adjusted odds ratio of 2.1 (95% CI, 1. 3 to 3.4; P:=0.0016) for carotid plaque compared with the first quartile. Ferritin was not associated with carotid plaque in men. Subjects who were heterozygous for the C282Y mutation constituted 11. 4% of the population, and there was no independent association of this genotype with either carotid IMT or focal plaque formation.

CONCLUSIONS

We conclude that in our community population, C282Y genotype status was not a risk predictor for either carotid mean IMT or plaque formation. Serum ferritin values in women were independently associated with carotid plaque.

Changing the site of delivery of thrombolytic treatment for acute myocardial infarction from the coronary care unit to the emergency department greatly reduces door to needle time

OBJECTIVE

To quantify the change in door to needle time when delivery of thrombolytic treatment of acute myocardial infarction was changed from the coronary care unit to the emergency department.

DESIGN

A comparative observational study using prospectively collected data.

SETTING

Coronary care unit and emergency department of an Australian teaching hospital.

PARTICIPANTS

89 patients receiving thrombolysis in coronary care unit between June 1994 and January 1996, and 100 patients treated in the emergency department between April 1997 and May 1998.

INTERVENTIONS

From April 1997, by agreement between cardiology and emergency medicine, all patients with acute myocardial infarction receiving thrombolysis were treated by emergency physicians in the emergency department.

MAIN OUTCOME MEASURE

Door to needle time measured from time of arrival at the hospital to start of thrombolysis. Other outcomes included pain to needle time and mortality.

RESULTS

Median door to needle times were less for patients treated in the emergency department than in the coronary care unit (37 minutes, 95% confidence interval (CI) 33 to 44 v 80 minutes, 95% CI 70 to 89, respectively; p < 0.0001). Door to needle time was under 60 minutes in 83% of emergency department patients and 26% of coronary care unit patients (57% difference, 95% CI 45% to 69%; p < 0.0001). Median pain to needle time was less for emergency department patients than for coronary care unit patients (161 minutes, 95% CI 142 to 177 v 195 minutes, 95% CI 180 to 209; p = 0.004); times of less than 90 minutes occurred in 18% of emergency department patients v 1% of coronary care unit patients (17% difference, 95% CI 9% to 25%; p < 0.05). Overall mortality was similar in patients treated in the emergency department and the coronary care unit.

CONCLUSIONS

With a collaborative interdepartmental approach, thrombolytic treatment of acute myocardial infarction was more rapid in the emergency department, without compromising patient safety. This should improve the outcome in patients with infarcts treated with thrombolytic agents.

Erectile dysfunction, sildenafil and cardiovascular risk

Cardiovascular risk factors are commonly associated with erectile dysfunction and should be identified and treated. Patients with cardiovascular diseases should be assessed and counselled regarding their fitness for sexual activity. The danger of concurrent use of sildenafil and nitrates under any circumstances, regardless of age and sex, must be highlighted at all levels of the community. Sildenafil is absolutely contraindicated in patients receiving treatment with long-acting nitrates for ischaemic heart disease. Patients who need sublingual short-acting nitrates infrequently should not be precluded from taking sildenafil, provided they are aware that sildenafil is not to be taken within 24 h of taking the nitrate.

Diffracted radiance: a fundamental quantity in nonparaxial scalar diffraction theory

Most authors include a paraxial (small-angle) limitation in their discussion of diffracted wave fields. This paraxial limitation severely limits the conditions under which diffraction behavior is adequately described. A linear systems approach to modeling nonparaxial scalar diffraction theory is developed by normalization of the spatial variables by the wavelength of light and by recognition that the reciprocal variables in Fourier transform space are the direction cosines of the propagation vectors of the resulting angular spectrum of plane waves. It is then shown that wide-angle scalar diffraction phenomena are shift invariant with respect to changes in the incident angle only in direction cosine space. Furthermore, it is the diffracted radiance (not the intensity or the irradiance) that is shift invariant in direction cosine space. This realization greatly extends the range of parameters over which simple Fourier techniques can be used to make accurate calculations concerning wide-angle diffraction phenomena. Diffraction-grating behavior and surface-scattering effects are two diffraction phenomena that are not limited to the paraxial region and benefit greatly from this new development.

Lack of association between seropositivity to Chlamydia pneumoniae and carotid atherosclerosis

Since the Chlamydia pneumoniae (C. pneumoniae)-specific antibody was shown to be associated with acute myocardial infarction and chronic coronary heart disease, the role of C. pneumoniae in the etiology of cardiovascular disease has been studied by a number of groups. We investigated the association between the C. pneumoniae-specific antibody, measured by microimmunofluorescence, risk factors for cardiovascular disease, and atherosclerosis in a randomly selected urban population. Overall, immunoglobulin-G (IgG) seroprevalence to C. pneumoniae in this sample of 1,034 subjects was 58%, whereas IgA seroprevalence was 32%. There was a decline in seropositivity with age for IgG but not IgA. Men were more likely than women to be IgG (66% vs 51%, chi-square p = 0.001) and IgA seropositive (36% vs 28%, chi-square p = 0.005). Current smokers had higher IgA seropositivity than nonsmokers (43% vs 30%). Those patients with a family history of cerebrovascular disease were more likely to have IgG antibody than those without (75% vs 57%, chi-square p= 0.007). Neither IgG nor IgA seropositivity was associated with the standard risk factors of hypertension, hyperlipidemia, or family history of ischemic heart disease, nor was seropositivity associated with carotid intima medial thickening (IMT) or atherosclerotic plaque as measured by carotid B-mode ultrasound. There was no difference between those participants who were IgG or IgA seropositive and seronegative in measurements of mean IMT, prevalence of abnormal IMT, and percentage with atherosclerotic plaque. In conclusion, although C. pneumoniae was associated with several risk factors for cardiovascular disease in a large cross-sectional population, we found no independent association between seroprevalence to C. pneumoniae and carotid atherosclerosis as measured by carotid IMT.

Angiotensin-converting enzyme gene polymorphism and carotid wall thickening in a community population

The insertion/deletion (I/D) polymorphism of the angiotensin-converting enzyme (ACE) gene has been associated with an increased risk of coronary heart disease, but whether it is a risk factor for underlying atherosclerosis remains unclear. Therefore, we examined to see whether the ACE gene deletion polymorphism was associated with carotid wall thickening and atherosclerotic plaque formation in a large randomly selected community population. A total of 1111 subjects, aged 27 to 77 years, with an equal male:female ratio and equal numbers in each age decile, were randomly selected from the Perth community population. Mean common carotid intima-medial wall thickness (IMT) and focal plaque formation were assessed by high-resolution B-mode ultrasound. The ACE gene I/D polymorphism was detected by PCR. The distribution of the ACE genotypes conformed to the Hardy-Weinberg equilibrium (DD, 31.0%; ID, 48.4%; and II, 20.6%). The D allele was strongly correlated in a codominant fashion with plasma ACE activity (r(s)=0.53, P<0.0001), and accounted for 33% of the total variance in circulating ACE activity. No significant differences among the ACE genotypes were found with respect to age, sex, and conventional risk variables, including a history of hypertension and vascular disease. The average mean IMT and prevalence of increased IMT and focal plaque were not significantly different among genotypes in the overall population or in the subset (n=852) who were conventionally low risk by Framingham coronary heart disease risk score. Logistic regression analysis selected age, systolic blood pressure, pack-years of smoking, LDL cholesterol level, waist/hip ratio, and history of hypertension, but not the D allele, as multivariate predictors of increased IMT and carotid plaque formation. We conclude that, although the ACE I/D polymorphism is strongly related to ACE activity, it is not a risk predictor of carotid wall thickening or focal plaque formation when examined in a large randomly selected community population.

Hyperhomocysteinemia but not the C677T mutation of methylenetetrahydrofolate reductase is an independent risk determinant of carotid wall thickening. The Perth Carotid Ultrasound Disease Assessment Study (CUDAS)

BACKGROUND

Hyperhomocysteinemia has been identified as a potential risk factor for atherosclerosis. This study examined whether a modest elevation of plasma total homocysteine (tHcy) was an independent risk factor for increased carotid artery intimal-medial wall thickness (IMT) and focal plaque formation in a large, randomly selected community population. We also examined whether vitamin cofactors and the C677T genetic mutation of the methylenetetrahydrofolate reductase (MTHFR) enzyme were major contributors to elevated plasma tHcy and carotid vascular disease.

METHODS AND RESULTS

In 1111 subjects (558 men, 553 women) 52+/-13 years old (mean+/-SD; range, 27 to 77 years) recruited from a random electoral roll survey, we measured fasting tHcy and performed bilateral carotid B-mode ultrasound. For the total population, mean tHcy was 12.1+/-4.0 micromol/L. Plasma tHcy levels were correlated with IMT (Spearman rank rs=0.31, P=0.0001). After adjustment for age, sex, and other conventional risk factors, subjects in the highest versus the lowest quartile of tHcy had an odds ratio of 2.60 (95% CI, 1.51 to 4.45) for increased IMT and 1.76 (95% CI, 1.10 to 2.82) for plaque. Serum and dietary folate levels and the C677T mutation in MTHFR were independent determinants of tHcy (all P=0.0001). The mutant homozygotes (10% of the population) had higher mean tHcy than heterozygotes or those without the mutation (14.2 versus 12.3 versus 11.6 micromol/L, respectively, P=0.0001). The inverse association of folate levels with tHcy was steeper in the mutant homozygotes. Despite this, the C677T MTHFR mutation was not independently predictive of increased carotid IMT or plaque formation.

CONCLUSIONS

Mild hyperhomocysteinemia is an independent risk factor for increased carotid artery wall thickness and plaque formation in a general population. Lower levels of dietary folate intake and the C677T mutation in MTHFR are important causes of mild hyperhomocysteinemia and may therefore contribute to vascular disease in the community.

The primary angioplasty vs thrombolysis debate

Early and complete coronary reperfusion can improve survival in myocardial infarction. Primary angioplasty can achieve TIMI grade 3 flow (complete restoration) in over 90% of cases. In comparison thrombolysis can achieve TIMI grade 3 flow in only just over 50%. Comparative trials have shown superior rates of death and reinfarction with a low haemorrhagic risk with PTCA compared with thrombolysis. Early clinical trials showed a clear superiority of primary angioplasty over thrombolysis but larger trials with larger number of endpoints have shown less impressive superiority. Wider application in community studies has not shown the benefits promised in the earlier studies, possibly due to dilution of experience. The impact of newer stent regimens vs nonnewer thrombolytic and antithrombotic regimens can only be determined by further clinical trials.

The benefits of beta-blockade at the time of myocardial infarction

Data from the World Health Organization Monitoring Trends and Determinants in Cardiovascular Disease (WHO MONICA) project, collected in Perth, are described. Patients taking a beta-blocker at the time of onset of myocardial infarction are a high-risk group, but univariate analysis of the data showed that the overall survival of patients on beta-blockers at 28 days was the same as for those not taking beta-blockers. A multiple logistic regression model analysis showed that the patients treated with beta-blockers had a survival advantage at 28 days, with a relative risk of death of 0.5. The mechanism of benefit is unclear. It does not appear to be an anti-arrhythmic effect, because beta-blockers did not affect survival in the first 24 h following a myocardial infarction, nor did they affect ventricular fibrillation. The effect may be due to a reduction in myocardial necrosis. Furthermore, an analysis of the incidence of coronary disease and type of drugs prescribed in Perth has indicated that beta-blockers may be contributing to a decrease in mortality due to coronary events.

Prevention of embolic complications in nonvalvular atrial fibrillation in the elderly

Atrial fibrillation is common in elderly subjects, usually with coexistent underlying heart disease. Nonvalvular atrial fibrillation is associated with increased morbidity and mortality, especially due to embolic complications: it carries a 5.6-fold increased risk of stroke, compared with age-matched controls. Three recent trials have demonstrated that prophylactic anticoagulation (either 'full' or 'partial') decreases the rate of stroke significantly, with an acceptably low rate of complications. The benefits of aspirin prophylaxis are less clear, and currently there is no evidence for a beneficial effect in the elderly patient. At present, no factor apart from a previous symptomatic embolism predicts those who are at risk of embolism. The risk of stroke appears to continue for a long time and, until data are provided, therapy should be continued indefinitely in the absence of contraindications. All patients with nonvalvular atrial fibrillation should be considered for prophylactic anticoagulants. Further work is required to identify those at highest risk, and to clarify how long therapy should be continued and whether there are subgroups in whom full or partial anticoagulation would be preferable.

A randomized comparison of intravenous heparin with oral aspirin and dipyridamole 24 hours after recombinant tissue-type plasminogen activator for acute myocardial infarction. National Heart Foundation of Australia Coronary Thrombolysis Group

BACKGROUND

This study addressed the need for heparin administration to be continued for more than 24 hours after coronary thrombolysis with recombinant tissue-type plasminogen activator (rt-PA).

METHODS AND RESULTS

A total of 241 patients with acute myocardial infarction were treated with 100 mg rt-PA and a bolus of 5,000 units i.v. heparin followed by 1,000 units/hr i.v. heparin for 24 hours. At 24 hours, 202 patients were randomized to continue intravenous heparin therapy (n = 99) in full dosage or to discontinue heparin therapy and begin an oral antiplatelet regimen of aspirin (300 mg/day) and dipyridamole (300 mg/day) (n = 103). On prospective recording, there were no differences in the pattern of chest pain, reinfarction, or bleeding complications. Coronary angiography on cardiac catheterization at 7-10 days showed no differences in patency of the infarct-related artery. The proportion of patients with total occlusion (TIMI grade 0-1) of the infarct-related artery was 18.9% in the heparin group and 19.8% in the aspirin and dipyridamole group. In the patients with an incompletely occluded infarct-related artery, the lumen was reduced by 69 +/- 2% of normal in the heparin group and 67 +/- 2% in the aspirin and dipyridamole group. Left ventricular function assessed on cardiac catheterization and radionuclide study at day 2 and at 1 month showed no differences between the two groups. Left ventricular ejection fraction on radionuclide ventriculography at 1 month was 52.4 +/- 1.2% in the heparin group and 51.9 +/- 1.2% in the aspirin and dipyridamole group.

CONCLUSIONS

We conclude that heparin therapy can be discontinued 24 hours after rt-PA therapy and replaced with an oral antiplatelet regimen without any adverse effects on chest pain, reinfarction, coronary patency, or left ventricular function.

Reduced risk of death at 28 days in patients taking a beta blocker before admission to hospital with myocardial infarction

OBJECTIVE

To see whether patients taking an oral beta blocker at the time of admission to hospital with myocardial infarction have a reduced risk of death at 28 days.

DESIGN

Retrospective analysis of data collected on patients admitted over four years.

SETTING

Community based study.

PATIENTS

2430 Consecutive patients living in the Perth statistical division admitted to hospital with myocardial infarction during 1984-7.

MAIN OUTCOME MEASURE

Survival at 28 days among patients taking a beta blocker at onset of myocardial infarction.

RESULTS

Patients were grouped into those who were and were not taking a beta blocker at the time of admission. Though patients taking a beta blocker were older and more likely to have a history of myocardial infarction, angina, or hypertension, the overall mortality at 28 days was similar in the two groups. A logistic regression model used to adjust for factors predictive of cardiac death at 28 days confirmed that patients taking a beta blocker at the time of admission had a significantly reduced risk of death (relative risk 0.50; 95% confidence interval 0.34 to 0.76). Though the incidence of fatal ventricular fibrillation was similar in the two groups, mean peak creatine kinase activity was significantly lower in the beta blocker group.

CONCLUSIONS

These data support the value of long term use of beta blockers in patients at risk of myocardial infarction. They suggest that patients taking these agents before admission to hospital with myocardial infarction have a significant survival advantage at 28 days, which may be due to a reduction in infarct size.