Age- and Sex-Specific Myocardial Blood Flow Values in Patients Without Coronary Atherosclerosis on Rb-82 PET Myocardial Perfusion Imaging

BACKGROUND

Quantitative myocardial blood flow (MBF) on positron-emission tomography myocardial perfusion imaging is a measure of the overall health of the coronary circulation. The ability to adequately augment blood flow, measured by myocardial blood flow reserve (MBFR), is associated with lower major adverse cardiovascular events and all-cause mortality. The age-specific ranges of MBFR in patients without demonstrable coronary artery disease have not been well established. We aimed to determine the effect of age and sex on MBF in a cohort of patients without demonstrable coronary artery disease.

METHODS

Patients who underwent positron-emission tomography myocardial perfusion imaging studies from 2012 to 2022 on positron-emission tomography/computed tomography cameras were included if the summed stress score was 0, the coronary calcium score was 0, and the left ventricular ejection fraction was ≥50%. Those with known coronary artery disease, prior history of coronary intervention, diabetes, heart/kidney/liver transplant, cirrhosis, or chronic kidney disease stage IV+ were excluded. MBF was calculated using a net retention model (ImagenQ, Cardiovascular Imaging Technologies, Kansas City), and quantile regression models were developed to predict MBF.

RESULTS

Among 2789 patients (age 59.9±13.0 years, 76.4% females), median rest MBF was 0.73 (0.60-0.91) mL/min·g, stress MBF was 1.72 (1.41-2.10) mL/min·g, and MBFR was 2.31 (1.96-2.74). Across all ages, males augmented MBF in response to vasodilator stress to a greater degree than females but achieved lower absolute stress MBF. Younger males in particular achieved a higher MBFR than their female counterparts, and this gap narrowed with increasing age. Predicted MBFR for a 20-year-old male was 3.18 and female was 2.50, while predicted MBFR for an 80-year-old male was 2.17 and female was 2.02.

CONCLUSIONS

In patients without demonstrable coronary artery disease, MBFR is higher in younger males than younger females and decreases with age in both sexes. Age- and sex-specific MBFR may be important in risk prediction and guidance for revascularization and warrant further study.

Economic and healthcare resource utilization assessments of PET imaging in Coronary Artery Disease diagnosis: a systematic review and discussion of opportunities for future economic evaluations

AIMS

This systematic literature review (SLR) consolidated economic and healthcare resource utilization (HCRU) evidence for positron emission tomography (PET) and single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) to inform future economic evaluations.

MATERIALS AND METHODS

An electronic search was conducted in MEDLINE, Embase, and Cochrane databases from 2012-2022. Economic and HCRU studies in adults who underwent PET- or SPECT-MPI for coronary artery disease (CAD) diagnosis were eligible. A qualitative methodological assessment of existing economic evaluations, HCRU, and downstream cardiac outcomes was completed. Exploratory meta-analyses of clinical outcomes were performed.

RESULTS

The search yielded 13,439 results, with 71 records included. Economic evaluations and comparative clinical trials were limited in number and outcome types (HCRU, downstream cardiac outcomes, and diagnostic performance) assessed. No studies included all outcome types and only one economic evaluation linked diagnostic performance to HCRU. The meta-analyses of comparative studies demonstrated significantly higher rates of early- and late-invasive coronary angiography and revascularization for PET- compared to SPECT-MPI; however, the rate of repeat testing was lower with PET-MPI. The rate of acute myocardial infarction was lower, albeit non-significant with PET- vs. SPECT-MPI.

LIMITATIONS AND CONCLUSIONS

This SLR identified economic and HCRU evaluations following PET- and SPECT-MPI for CAD diagnosis and determined that existing studies do not capture all pertinent outcome parameters or link diagnostic performance to downstream HCRU and cardiac outcomes, thus, resulting in simplified assessments of CAD burden. A limitation of this work relates to heterogeneity in study designs, patient populations, and follow-up times of existing studies. Resultingly, it was challenging to pool data in meta-analyses. Overall, this work provides a foundation for the development of comprehensive economic models for PET- and SPECT-MPI in CAD diagnosis, which should link diagnostic outcomes to HCRU and downstream cardiac events to capture the full CAD scope.

Sex differences in diagnostic modalities of coronary artery disease: Evidence from coronary microcirculation

Although atherosclerosis is usually considered a disease of the large arteries, risk factors for atherosclerosis also trigger structural and functional abnormalities at a microvascular level. In cardiac disease, microvascular dysfunction is especially relevant in women, among whom the manifestation of ischemic disease due to impaired coronary microcirculation is more common than in men. This sex-specific clinical phenotype has important clinical implications and, given the higher pre-test probability of coronary microvascular dysfunction in females, different diagnostic modalities should be used in women compared to men. In this review, we summarize invasive and non-invasive diagnostic modalities to assess coronary microvascular function, ranging from catheter-based evaluation of endothelial function to Doppler echocardiography and positron emission tomography. Moreover, we discuss different clinical settings in which microvascular disease plays an important role, underlining the importance of choosing the right diagnostic modality depending on the sex of the patients.

Associations of cardiovascular and diabetes-related risk factors with myocardial perfusion reserve assessed by 201Tl/99mTc-tetrofosmin single-photon emission computed tomography in patients with diabetes mellitus and stable coronary artery disease

We aimed to examine the associations of cardiovascular risk factors with myocardial perfusion reserve (MPR) in patients with type 2 diabetes and stable coronary artery disease. The study patients were retrospectively identified from a database of patients with diabetes and stable coronary artery disease at Asan Medical Center (Seoul, Republic of Korea), covering the period from 2017 to 2019. The primary outcome variable was MPR assessed by dynamic stress 201Tl/rest 99mTc-tetrofosmin SPECT. Univariable and stepwise multivariable analyses were performed to assess the associations of cardiovascular risk factors with MPR. A total of 276 patients (236 men and 40 women) were included. The median global MPR was 2.4 (interquartile range 1.9-3.0). Seventy-five (27.2%) patients had an MPR < 2.0. Multivariable linear regression showed that smoking (ß = - 0.44, 95% confidence interval - 0.68 to - 0.21, P < 0.001), hypertension (ß = - 0.24, 95% confidence interval - 0.47 to - 0.02, P = 0.033), and summed difference score (ß = - 0.05, 95% confidence interval - 0.07 to - 0.03, P < 0.001) were independently associated with MPR. Abnormal MPR (< 2.0) was associated with a higher incidence of cardiac death or myocardial infarction (P = 0.034). MPR assessed by dynamic stress 201Tl/rest 99mTc-tetrofosmin SPECT was impaired in a large cohort of patients with diabetes. After adjusting for risk variables, including standard myocardial perfusion imaging characteristics, smoking, and hypertension were associated with MPR. Our results may aid in identifying patients with impaired MPR and stratifying patients with type 2 diabetes.

Imaging of heart disease in women: review and case presentation

Cardiovascular diseases (CVD) remain the leading cause of mortality worldwide. Although major diagnostic and therapeutic advances have significantly improved the prognosis of patients with CVD in the past decades, these advances have less benefited women than age-matched men. Noninvasive cardiac imaging plays a key role in the diagnosis of CVD. Despite shared imaging features and strategies between both sexes, there are critical sex disparities that warrant careful consideration, related to the selection of the most suited imaging techniques, to technical limitations, and to specific diseases that are overrepresented in the female population. Taking these sex disparities into consideration holds promise to improve management and alleviate the burden of CVD in women. In this review, we summarize the specific features of cardiac imaging in four of the most common presentations of CVD in the female population including coronary artery disease, heart failure, pregnancy complications, and heart disease in oncology, thereby highlighting contemporary strengths and limitations. We further propose diagnostic algorithms tailored to women that might help in selecting the most appropriate imaging modality.

Gender difference in association between diabetes mellitus and all-cause mortality in atrial fibrillation patients

OBJECTIVE

There may be gender difference in correlation of diabetes mellitus (DM) and cardiovascular events. We attempt to investigate whether there is gender-heterogeneity in one-year outcomes of atrial fibrillation (AF) patients with DM or not.

METHODS

Patients who were diagnosed with AF admitted to the emergency departments in the Chinese AF Multicenter Registry study were enrolled. Basic demographics information, initial Blood Pressure and heart rate, medical histories, and treatments of each patient were collected. Follow-up was carried out with a mean duration of one year. The primary endpoint was all-cause mortality and systemic embolism.

RESULTS

A total of 2016 patients were selected from September 2008 and April 2011. All-cause mortality was significantly higher in male AF patients with DM than those without (21.8 % & 13.6 %, P = 0.014). Cox regression analysis showed that there was an interaction between gender and DM for one-year all-cause mortality (P = 0.049). DM was significantly associated with one-year all-cause mortality regardless of univariate analysis (HR = 1.436, 95%CI:1.079-1.911, P = 0.013) or multivariate analysis (HR = 1.418, 95%CI: 1.059-1.899, P = 0.019). For male patients with AF, DM was significantly associated with one-year all-cause mortality (P = 0.048), but not for female patients with AF (P = 0.362).

CONCLUSION

DM was independently associated with one-year all-cause mortality in the entire cohort of AF patients. This association was found mainly in male patients with AF, but not in female patients. DM management programs may need to reflect gender difference.

Cardiovascular diseases in people with diabetes mellitus in Spain according to the Primary Care Clinical Database (BDCAP) in 2017

INTRODUCTION AND OBJECTIVES

Atherosclerotic cardiovascular disease and heart failure are the leading cause of morbidity and mortality in patients with diabetes. The objective of this work is to know the prevalence of atherosclerotic cardiovascular diseases and heart failure in people diagnosed with diabetes in Spain during 2017 and compare them with those not diagnosed with diabetes according to age and sex.

METHODS

Data for diagnoses of diabetes mellitus (DM), acute myocardial infarction (AMI), stroke, peripheral artery disease (PAD) or heart failure (HF) for 2017 were obtained from the National Health System's Primary Care Clinical Database (BDCAP).

RESULTS

Comparing people with diabetes and people without diabetes over 35 years of age, the Odds Ratio (OR) for being diagnosed with acute myocardial infarction, stroke, peripheral artery disease or heart failure is about 2 in those over 64 years of age and more than 4 in patients under that age. This OR is superior in females versus males for all diagnoses apart from peripheral artery disease.

CONCLUSIONS

This study shows the high cardiovascular comorbidity of patients with diabetes in Spain, with a greater excess of risk in patients under 65 years of age, more pronounced in women. We should offer more intensive treatment for DM2 in women.

Determinants and prognostic implications of instantaneous wave-free ratio in patients with mild to intermediate coronary stenosis: Comparison with those of fractional flow reserve

The instantaneous wave-free ratio (iFR) is used for assessing the hemodynamic severity of a lesion, as an alternative to the fractional flow reserve (FFR). We evaluated the relationship between iFR and FFR in detail and the clinical significance of iFR in patients with mild to intermediate coronary artery stenosis. We recruited consecutive 323 patients (421 lesions) with lesions exhibiting 30% to 80% diameter stenosis on angiography in whom FFR and iFR were measured. In the total lesions, mean diameter stenosis was 48.6% ± 9.0%, and physiological significance, defined by FFR of 0.80 or less or by iFR of 0.92 or less, was observed in 32.5% or 33.5%, respectively. Mismatch between iFR and FFR was observed in 18.1% of the lesions. Clinical factors did not predict FFR value; however, gender, diabetes mellitus, aortic stenosis, anemia, high-sensitivity CRP value, and renal function predicted iFR value. In multivariate logistic analysis after adjustment for FFR value, gender (p < 0.001), diabetes mellitus (p = 0.005), aortic stenosis (p = 0.016), high-sensitivity CRP (p < 0.001), and renal function (p = 0.003) were all independent predictors of iFR value. In Kaplan-Meier analysis, the baseline iFR predicted the subsequent major cardiovascular events (MACE) (hazard ratio, 2.40; 95% CI, 1.16–4.93; p = 0.018) and the results of the iFR-guided strategy for predicting rates of MACE and myocardial infarction/revascularization were superior to those of the FFR-guided strategy. In conclusion, significant clinical factors predicted iFR value, which affected the prognostic capacity. The iFR-guided strategy may be superior in patients with mild to intermediate stenosis.