Systematic assessment of procedural parameters, influence on downstream testing and 12-month outcomes of a CT-myocardial perfusion service.

AIMS: This study describes the real-world referral pattern of patients to a CT myocardial perfusion service, the technical issues associated with providing the service, the results of the studies, and the subsequent downstream utilization of other investigations, and patient outcomes. METHODS AND RESULTS: 115 consecutive patients underwent CTA, dynamic rest and dipyridamole-stress perfusion scanning. There were 29 (25%) and 14 (12%) patients who had reversible defects and fixed defects respectively, indicating abnormal flow reserve and previous infarction respectively. In the patients with fixed defects, delayed hyperenhancement was noted in all, indicative of prior infarction, scarring and non-viability. With the existing CTA Appropriateness Criteria, the categorization of "Appropriate," "Of Uncertain Appropriateness", and "Inappropriate" would have been applied to 25%, 25% and 50% of the present studies respectively. Up to 72% could have been referred for ischemia evaluation with other modalities of functional imaging after the non-diagnostic CT angiogram. Follow up was complete in 113 subjects (98%) over a period of 14 ±â€¯8 months. In the 29 patients with abnormal flow reserve and CAD, 62% underwent invasive angiography and 94%, angioplasty within a 90-day period. In the patients who underwent angioplasty, all remained free of myocardial infarction or death and 88% remained free of myocardial infarction, death or readmission over a mean of 14 ±â€¯8 months. CONCLUSION: A CT-myocardial perfusion service provided measures of ischemia and infarct detection over that of CTA alone. The information was utilized clinically by doctors to support a strategy of referral to revascularization versus conservative medical management.

Ethnic differences in atrial fibrillation in patients with heart failure from Asia-Pacific.

OBJECTIVE: Ethnic differences in the prevalence of atrial fibrillation (AF) in heart failure (HF) remain unclear. We compared the prevalence and clinical correlates of AF among different ethnicities in an Asian-Pacific population with HF. METHODS: Patients with validated HF were prospectively studied across Singapore and New Zealand (NZ). RESULTS: Among 1746 patients with HF (62% Asian, 26% women, mean age 66 (SD 13) years, mean ejection fraction (EF) 37 (SD 16%), 39% had AF. The prevalence of AF was markedly lower in Singapore-Asians than NZ-Europeans (24% vs 63%; p<0.001), even after adjusting for age, clinical and echocardiographic covariates, regardless of EF group (pinteraction for EF=0.39). Patients with AF were older, had higher body mass index and were more likely to have a history of hypertension, stroke, peripheral vascular disease, renal disease, chronic respiratory disease and increased alcohol intake, but less likely to have diabetes. Clinical correlates were similar for Asians and NZ-Europeans, except diabetes: Asian diabetic patients with HF had less AF compared with Asian patients without diabetes (OR 0.66, 95% CI 0.50 to 0.88), whereas among NZ-Europeans there was no significant association between diabetes and AF (OR 1.22, 95% CI 0.85 to 1.75) (pinteraction for ethnicity=0.01). AF was associated with a higher crude composite outcome of mortality and HF hospitalisations at 2 years (HR 1.19, 95% CI 1.02 to 1.38). CONCLUSION: There is a strikingly lower prevalence of AF among Asian compared with NZ-European patients with HF. The underlying mechanisms for the lower prevalence of AF among Asians, particularly in the presence of diabetes, deserve further study. TRIAL REGISTRATION NUMBER: ACTRN12610000374066.

Influence of Ethnicity, Age, and Time on Sex Disparities in Long-Term Cause-Specific Mortality After Acute Myocardial Infarction.

BACKGROUND: We examined the influence of sex, ethnicity, and time on competing cardiovascular and noncardiovascular causes of death following acute myocardial infarction in a multiethnic Asian cohort. METHODS AND RESULTS: For 12 years, we followed a prospective nationwide cohort of 15 151 patients (aged 22-101 years, median age 63 years; 72.3% male; 66.7% Chinese, 19.8% Malay, 13.5% Indian) who were hospitalized for acute myocardial infarction between 2000 and 2005. There were 6463 deaths (4534 cardiovascular, 1929 noncardiovascular). Compared with men, women had a higher risk of cardiovascular death (age-adjusted hazard ratio [HR] 1.3, 95% CI 1.2-1.4) but a similar risk of noncardiovascular death (HR 0.9, 95% CI 0.8-1.0). Sex differences in cardiovascular death varied by ethnicity, age, and time. Compared with Chinese women, Malay women had the greatest increased hazard of cardiovascular death (HR 1.4, 95% CI 1.2-1.6) and a marked imbalance in death due to heart failure or cardiomyopathy (HR 3.4 [95% CI 1.9-6.0] versus HR 1.5 [95% CI 0.6-3.6] for Indian women). Compared with same-age Malay men, Malay women aged 22 to 49 years had a 2.5-fold (95% CI 1.6-3.8) increased hazard of cardiovascular death. Sex disparities in cardiovascular death tapered over time, least among Chinese patients and most among Indian patients; the HR comparing cardiovascular death of Indian women and men decreased from 1.9 (95% CI 1.5-2.4) at 30 days to 0.9 (95% CI 0.5-1.6) at 10 years. CONCLUSION: Age, ethnicity, and time strongly influence the association between sex and specific cardiovascular causes of mortality, suggesting that health care policy to reduce sex disparities in acute myocardial infarction outcomes must consider the complex interplay of these 3 major modifying factors.

Ethnic differences in the association of QRS duration with ejection fraction and outcome in heart failure.

BACKGROUND: QRS duration (QRSd) criteria for device therapy in heart failure (HF) were derived from predominantly white populations and ethnic differences are poorly understood. METHODS: We compared the association of QRSd with ejection fraction (EF) and outcomes between 839 Singaporean Asian and 11 221 Swedish white patients with HF having preserved EF (HFPEF)and HF having reduced EF (HFREF) were followed in prospective population-based HF studies. RESULTS: Compared with whites, Asian patients with HF were younger (62 vs 74 years, p<0.001), had smaller body size (height 163 vs 171 cm, weight 70 vs 80 kg, both p<0.001) and had more severely impaired EF (EF was <30% in 47% of Asians vs 28% of whites). Overall, unadjusted QRSd was shorter in Asians than whites (101 vs 104 ms, p<0.001). Lower EF was associated with longer QRSd (p<0.001), with a steeper association among Asians than whites (pinteraction<0.001), independent of age, sex and clinical covariates (including body size). Excluding patients with left bundle branch block (LBBB) and adjusting for clinical covariates, QRSd was similar in Asians and whites with HFPEF, but longer in Asians compared with whites with HFREF (p=0.001). Longer QRSd was associated with increased risk of HF hospitalisation or death (absolute 2-year event rate for ≤120 ms was 40% and for >120 ms it was 52%; HR for 10 ms increase of QRSd was 1.04 (1.03 to 1.06), p<0.001), with no interaction by ethnicity. CONCLUSION: We found ethnic differences in the association between EF and QRSd among patients with HF. QRS prolongation was similarly associated with increased risk, but the implications for ethnicity-specific QRSd cut-offs in clinical decision-making require further study.