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Biomedical subjects

Adam Timmis

Publications and source records attributed to Adam Timmis.

7 recordsLinked to original sources
PubMed2006

Cardiothoracic ratio within the "normal" range independently predicts mortality in patients undergoing coronary angiography.

OBJECTIVE: To determine whether cardiothoracic ratio (CTR), within the range conventionally considered normal, predicted prognosis in patients undergoing coronary angiography. DESIGN: Cohort study with a median of 7-years follow-up. SETTING: Consecutive patients undergoing coronary angiography at Barts and The London National Health Service (NHS) Trust. SUBJECTS: 1005 patients with CTRs measured by chest radiography, and who subsequently underwent coronary angiography. Of these patients, 7.3% had a CTR > or =0.5 and were excluded from the analyses. OUTCOMES: All-cause mortality and coronary event (non-fatal myocardial infarction or coronary death). Adjustments were made for age, left ventricular dysfunction, ACE inhibitor treatment, body mass index, number of diseased coronary vessels and past coronary artery bypass graft. RESULTS: The risk of death was increased among patients with a CTR in the upper part of the normal range. In total, 94 (18.9%) of those with a CTR below the median of 0.42 died compared with 120 (27.8%) of those with a CTR between 0.42 and 0.49 (log rank test p<0.001). After adjusting for potential confounders, this increased risk remained (adjusted HR 1.45, 95% CI 1.03 to 2.05). CTR, at values below 0.5, was linearly related to the risk of coronary event (test for trend p = 0.024). CONCLUSION: In patients undergoing coronary angiography, CTR between 0.42 and 0.49 was associated with higher mortality than in patients with smaller hearts. There was evidence of a continuous increase in risk with higher CTR. These findings, along with those in healthy populations, question the conventional textbook cut-off point of > or =0.5 being an abnormal CTR.

Anthropometry↗
PubMed2006

Comparison of the relation between renal impairment, angiographic coronary artery disease, and long-term mortality in women versus men.

Mild to moderate renal impairment has recently been associated with increased cardiovascular mortality. However, gender differences in the association of mild to moderate renal impairment with the presence of angiographic coronary artery disease and long-term mortality remain unknown. We examined a prospective cohort of consecutive patients who underwent coronary angiography from the ACRE study in the Royal Hospitals Trust (London, United Kingdom) with referral from 5 contiguous health authorities. Among 1,609 patients (465 women) who had angiographic and serum creatinine measurements at baseline, renal impairment at modification of diet in renal disease glomerular filtration rates of 45 to 59, 30 to 44, and <30 ml/min/1.73 m(2) was more common in women than in men and was significantly associated with the presence of angiographic coronary artery disease in women but not in men. At each level of glomerular filtration rate, multivariate adjusted hazard ratios of 7-year all-cause mortality for women compared with men were higher: 2.64 (95% confidence intervals [CI] 1.21 to 5.73) versus 1.34 (95% CI 0.995 to 1.79); 2.62 (95% CI 1.12 to 16.12) versus 2.35 (95% CI 1.60 to 3.43); and 10.42 (95% CI 3.97 to 27.39) versus 4.77 (95% CI 2.95 to 7.70), respectively. Similar patterns were observed in cardiovascular and coronary deaths. In conclusion, mild to moderate renal impairment may be a marker for unmeasured proatherogenic factors for women only, and women may bear a greater mortality burden that is attributable to renal impairment compared with men. Gender may influence the prognostic effect of renal impairment in coronary disease.

Aged↗
PubMed2005

Recruiting patients to medical research: double blind randomised trial of "opt-in" versus "opt-out" strategies.

OBJECTIVE: To evaluate the effect of opt-in compared with opt-out recruitment strategies on response rate and selection bias. DESIGN: Double blind randomised controlled trial. SETTING: Two general practices in England. PARTICIPANTS: 510 patients with angina. INTERVENTION: Patients were randomly allocated to an opt-in (asked to actively signal willingness to participate in research) or opt-out (contacted repeatedly unless they signalled unwillingness to participate) approach for recruitment to an observational prognostic study of patients with angina. MAIN OUTCOME MEASURES: Recruitment rate and clinical characteristics of patients. RESULTS: The recruitment rate, defined by clinic attendance, was 38% (96/252) in the opt-in arm and 50% (128/258) in the opt-out arm (P = 0.014). Once an appointment had been made, non-attendance at the clinic was similar (20% opt-in arm v 17% opt-out arm; P = 0.86). Patients in the opt-in arm had fewer risk factors (44% v 60%; P = 0.053), less treatment for angina (69% v 82%; P = 0.010), and less functional impairment (9% v 20%; P = 0.023) than patients in the opt-out arm. CONCLUSIONS: The opt-in approach to participant recruitment, increasingly required by ethics committees, resulted in lower response rates and a biased sample. We propose that the opt-out approach should be the default recruitment strategy for studies with low risk to participants.

Adult↗
PubMed2004

Prospective validity of measuring angina severity with Canadian Cardiovascular Society class: The ACRE study.

BACKGROUND: Although the prevalence of angina remains high, the importance of grading angina severity is unclear. OBJECTIVES: To determine the extent to which angina severity is associated with angiographic findings, and the rate of revascularization, mortality and nonfatal myocardial infarction. METHODS: Prospective, population-based study with a 2.5-year follow-up of 2849 consecutive patients with angina undergoing coronary angiography at Barts and the London NHS Trust, London, United Kingdom, in the Appropriateness of Coronary Revascularisation (ACRE) study. Angina severity was assessed with the Canadian Cardiovascular Society (CCS) classification, ranging from class I (mild) to IV (severe). Outcome measures were revascularization rates, and all-cause mortality and nonfatal myocardial infarction. RESULTS: In age-adjusted analyses, a higher CCS class was linearly associated (P<0.001) with a higher number of diseased vessels and impaired left ventricular function. When adjusting for age, sex, smoking, history of hypertension, diabetes, number of diseased vessels, left ventricular function, use of acetylsalicylic acid, beta-blockers or statins, and revascularization status (for death and nonfatal myocardial infarction), a higher CCS class was linearly associated with higher coronary angioplasty (P<0.001) and bypass graft (P=0.03) rates, and lower all-cause mortality and nonfatal myocardial infarction (P<0.001; CCS IV versus I: hazard ratio 2.44, 95% CI 1.46 to 4.09). CONCLUSION: CCS class was linearly associated with angiographic findings, revascularization rates, mortality and nonfatal myocardial infarction. These findings support the importance of a four-level grading of symptom severity among angina patients.

Angina Pectoris↗