Relationship between coronary artery calcium score and myocardial blood flow reserve in patients with suspected coronary artery disease

Funding Acknowledgements

Type of funding sources: None.

Background

Both the Coronary Artery Calcium Score (CACS), a non-invasive surrogate for atherosclerotic burden, and reduced myocardial blood flow reserve (MBFR) with normal perfusion, a non-invasive surrogate for coronary vasomotor dysfunction, independently predict future cardiovascular events. The relationship between CACS and MBFR, and potential clinical factors affecting it, is not well understood.

Methods

Among 9467 consecutive patients without known history of CAD who had normal perfusion on 82Rb PET-CT and a concomitantly measured CACS between 01/2010 - 06/2020 within our health system, we assessed the relationship between CACS and MBFR. Multiple linear regression was used to predict MBFR using CACS, adjusted for age, sex, BMI, risk factors, symptoms, resting LVEF and vital signs. Interactions of age, sex, diabetes, and symptoms with CACS were assessed to evaluate if they modified the relationship of CACS with MBFR.

Results

Mean age (SD) of the study cohort was 66.4 (12.6) years, 64% were women, 64% had chest pain and 47% had dyspnea. Reduced MBFR (<2) was present in 44% and CAC >0 in 74% of patients.  There was a modest inverse correlation between MBFR and CACS, r= - 0.18, p = < 0.0001 (Figure). In adjusted analyses, CACS (β for CAC per 100 = -0.013 [95% CI: -0.015, -0.010]) was weakly associated with MBFR, and age, sex, diabetes, or symptoms did not modify this relationship (all interaction p-values >0.1). Older age, female sex, presence of hypertension, diabetes, dyspnea, lower LVEF, higher baseline HR and higher CACS independently predicted reduced MBFR, but explained only 20% of the variance in MBFR (R2 =0.20).

Conclusion

There is a weak relationship between CACS and MBFR, which is not modified by age, sex, symptoms, or other CV risk factors. Coronary calcium burden does not completely reflect the overall disease activity within the coronary circulation, and measures of coronary vasomotor function such as MBFR may offer complementary information on CAD risk to that provided by the total burden of calcified atherosclerosis.

Relationship between country income, socioeconomic factors and control of cardiovascular disease risk factors in patients with type 2 Diabetes: insights from the global DISCOVER registry

Background

In patients with type 2 diabetes (T2D), optimal management of cardiovascular (CV) risk factors is critical for primary prevention of CV disease.

Purpose

To describe the association of country income and patient socioeconomic factors with risk factor control in patients with T2D.

Methods

DISCOVER is a 37-country, prospective, observational study of 15,983 patients with T2D enrolled between January 2016 and December 2018 at initiation of 2nd-line glucose-lowering therapy and followed for 3 years. In patients without known CV disease with sub-optimally controlled risk factors at baseline, we examined achievement of risk factor control (HbA1c <7%, BP <140/90 mmHg, appropriate statin) at the 3 year follow-up. Countries were stratified by gross national income (GNI)/capita, per World Bank report. We explored variability across countries in risk factor control achievement using hierarchical logistic regression models and examined the association of country- and patient-level economic factors with risk factor control.

Results

Among 9,613 patients with T2D but without CV disease (mean age 57.2 years, 47.9% women), 83.1%, 37.5%, and 66.3% did not have optimal control of glucose, BP, and statins, respectively, at baseline. Of these, 40.8%, 55.5%, and 28.6% achieved optimal control at 3 years of follow-up. There was substantial variability in achievement of risk factor control across countries (Figure) but no association of country GNI/capita on achievement of risk factor control (Table). Insurance status, which differed substantially by GNI group, was strongly associated with glycemic control, with no insurance and public insurance associated with lower odds of patients achieving HbA1c <7%.

Conclusions

In a global cohort of patients with T2D, a substantial proportion do not achieve risk factor control even after 3 years of follow-up. The variability across countries in risk factor control is not explained by the GNI/capita of the country.

Proportion of patients at goal

Funding Acknowledgement

Type of funding source: Private company. Main funding source(s): The DISCOVER study is funded by AstraZeneca