Addressing Knowledge Gaps in the 2013 ACC/AHA Guideline on the Assessment of Cardiovascular Risk: a Review of Recent Coronary Artery Calcium Literature

Radiation Doses in Patients Undergoing Computed Tomographic Coronary Artery Calcium Evaluation With a 64-Slice Scanner Versus a 256-Slice Scanner

Computed tomographic coronary artery calcium scanning enables cardiovascular risk stratification; however, exposing patients to high radiation levels is an ongoing concern. New-generation computed tomographic systems use lower radiation doses than older systems do. To quantify comparative doses of radiation exposure, we prospectively acquired images from 220 patients with use of a 64-slice GE LightSpeed VCT scanner (control group, n=110) and a 256-slice GE Revolution scanner (study group, n=110). The groups were matched for age, sex, and body mass index; statistical analysis included t tests and linear regression. The mean dose-length product was 21% lower in the study group than in the control group (60.2 ± 27 vs 75.9 ± 22.6 mGy·cm; P <0.001) and also in each body mass index subgroup. Similarly, the mean effective radiation dose was 21% lower in the study group (0.84 ± 0.38 vs 1.06 ± 0.32 mSv) and lower in each weight subgroup. After adjustment for sex, women in the study group had a lower dose-length product (50.4 ± 23.4 vs 64.7 ± 27.6 mGy·cm) than men did and received a lower effective dose (0.7 ± 0.32 vs 0.9 ± 0.38 mSv) (P=0.009). As body mass index and waist circumference increased, so did doses for both scanners. Our study group was exposed to radiation doses lower than the previously determined standard of 1 mSv, even after adjustment for body mass index and waist circumference. In 256-slice scanning for coronary artery calcium, radiation doses are now similar to those in lung cancer screening and mammography.

Alcohol-related cirrhosis is associated with high coronary artery calcium scores in patients undergoing evaluation for orthotopic liver transplantation

BACKGROUND AND AIMS

Coronary artery disease is a major cause of morbidity and mortality in liver transplant patients. Coronary artery calcium (CAC) score has been used to evaluate the risk of CAD in non-cirrhotic patients. However, its significance in cirrhotic patients is unknown. This study aimed to identify factors associated with elevated CAC scores in patients with end-stage liver disease undergoing liver transplant evaluation.

METHODS

We retrospectively reviewed all patients who underwent liver transplantation evaluation and had coronary CT scan between January 2015 and December 2018. Patients with prior history of CAD were excluded. CAC score was calculated based on the method described by Agatston.

RESULTS

Sixty-two patients were included. 37.1% had alcohol-related liver disease and 27.4% had NASH cirrhosis. Mean CAC score was 261.1 ± SD, 463.84. Alcohol-related liver disease, male gender, and hypertension were significantly associated with CAC score >100 and only alcohol-related liver disease was associated with CAC score >300. In logistic regression, patients with alcohol-related liver disease had more than sixfold increase in risk of having CAC scores >100 and 300 (OR 6.14, and 6.70, respectively).

CONCLUSION

Alcohol-related liver disease, male gender, and hypertension were significantly associated with an increased CAC score >100. However, alcohol-related liver disease was the only factor associated with CAC score >300.

Clinical value of detecting autoantibodies against β1-, β2,- and α1-adrenergic receptors in carvedilol treatment of patients with heart failure

Objective

To determine the possible association of anti-β₁-adrenergic receptors (anti-β₁-AR), anti-β₂-AR and anti-α₁-AR with carvedilol treatment in patients with heart failure (HF).

Methods

A total of 267 HF patients were prospectively enrolled. Blood samples were measured by an enzyme-linked immunosorbent assay. All of the patients received carvedilol for their HF. Each patient was followed up for six months and their cardiac function was measured.

Results

The final analysis encompassed 137 patients comprising 65 patients with three autoantibodies (positive group) and 72 patients without all three autoantibodies but with one or two autoantibodies (negative group). The frequency and geometric mean titer of anti-β₁-AR, anti-β₂-AR, and anti-α₁-AR were significantly lower in the group without all three autoantibodies after six months of carvedilol treatment (all P < 0.01; from 100% to 57%, 50%, and 49%, respectively; and from 1: 118, 1: 138, and 1: 130 to 1: 72, 1: 61, and 1: 67, respectively). Furthermore, 28 patients in the positive group demonstrated complete ablation of autoantibodies. In addition, left ventricular remodelling and function was significantly improved by the use of carvedilol combined with the standard treatment regime for six months in the positive group (P < 0.01) when compared to the negative group (P < 0.05).

Conclusions

Carvedilol treatment significantly decreases frequency and geometric mean titer in patients with all three autoantibodies, even up to complete ablation, and significantly improved cardiac function and remodelling. The effect of carvedilol is probably correlated to the presence of all three autoantibodies.

Multisite atherosclerosis in subjects with metabolic syndrome and diabetes and relation to cardiovascular events: The Multi-Ethnic Study of Atherosclerosis

BACKGROUND AND AIMS

The extent and relation of multisite atherosclerosis to cardiovascular disease (CVD) in metabolic syndrome (MetS) and diabetes (DM) are not well documented. We examined the extent of multisite atherosclerosis and its prognostic value for CVD events in MetS and DM.

METHODS

In CVD-free subjects from the Multi-Ethnic Study of Atherosclerosis, multisite atherosclerosis was measured as: (1) the number of arterial beds involved (coronary calcium>0, abdominal aortic calcium>0, carotid intima-media thickness ≥1 mm and ankle brachial index<1 or ≥1.4); (2) a composite score summing the quartile rank for each atherosclerosis measure. Hazard ratios (HRs) and c-statistics were calculated for incident CVD and coronary heart disease (CHD) over 10.6 years.

RESULTS

Of 1675 individuals (mean age 64 years, 51% male), 33.4% had MetS and 15.9% had DM. The number of atherosclerotic sites was higher in those with DM (mean ± SD = 1.67 ± 1.15) and MetS (1.49 ± 1.12) versus neither MetS/DM (1.09 ± 1.09) (p < 0.0001). CVD rates per 1000 person-years ranged from 3.5, 8.2, and 10.0 in those with 0 sites positive to 35.1, 79.6 and 103.4 in those with 4 sites positive among neither DM/MetS, MetS and DM groups, respectively. HRs (95% CI) for CVD comparing those with 4 vs. 0 atherosclerotic sites were 4.0 (0.8-19.1), 4.9 (2.0-12.0), and 14.4 (3.6-57.6), respectively. C-statistics adding multisite atherosclerosis measures increased over models without the measures and with CIMT or ABI but not CAC.

CONCLUSIONS

Multisite atherosclerosis is greater with MetS or DM, and predicts CVD and CHD events. Risk prediction is improved over CIMT and ABI but not CAC.

Delphi Analysis of Science Gaps in the 2015 American Heart Association Cardiac Arrest Guidelines

Background

Current cardiac arrest guidelines have limited high‐quality scientific evidence to support recommendations for care. The quality of scientific evidence on which guidelines are based may correlate with improved patient outcomes and meaningful survival. We sought to develop a prioritized list of knowledge gaps in resuscitation to assist researchers, policy makers, and funding agencies in their decision‐making process.

Methods and Results

A 4‐stage modified Delphi method was used with a panel of cardiac arrest experts. Experts addressed the prompt: “What are the top 3 gaps in knowledge involving cardiac arrest care that should be research priorities for National Institutes of Health/American Heart Association funding to have the greatest impact on public health?” Knowledge gaps were identified in the initial round, rated in a second round, and rank ordered in the third round, and they underwent final review and consensus (final round). The outcome was 10 knowledge gaps, with prioritization of the top 3 gaps. A total of 61 gaps, with 19 distinct themes, were identified by participants. The 10 knowledge gaps most likely to affect public health identified by the expert panel included, in order, the following: telecommunicator cardiopulmonary resuscitation, hemodynamic monitoring for goal‐directed resuscitation, reasons why bystanders fail to respond, optimization of postarrest care, out‐of‐hospital cardiac arrest identification and response, individualizing resuscitation strategies, predicting patients at risk, tools for neuroprognostication, optimal airway management, and optimizing educational strategies.

Conclusions

Ten priorities for cardiac arrest research were identified, but consensus was not reached on the prioritized top 3. Future research should address these gaps to potentially improve resuscitation guideline evidence quality.

High-pitch versus sequential mode for coronary calcium in individuals with a high heart rate: Potential for dose reduction

BACKGROUND

To determine the impact of high-pitch spiral acquisition on radiation dose and cardiovascular disease (CVD) risk stratification by coronary artery calcium (CAC) assessment with computed tomography in individuals with a high heart rate.

METHODS

Of the ROBINSCA trial, 1990 participants with regular rhythm and heart rates >65 beats per minute (bpm) were included. As reference, 390 participants with regular heart rates ≤65 bpm were used. All participants underwent prospectively electrocardiographically(ECG)-triggered imaging of the coronary arteries using dual source CT at 120 kVp, 80 ref mAs using both high-pitch spiral mode and sequential mode. Radiation dose, Agatston score, number of positive scores, as well as median absolute difference of the Agatston score were determined and participants were stratified into CVD risk categories.

RESULTS

A similar percentage of participants with low heart rates and high heart rates had a positive CAC score in data sets acquired in high-pitch spiral (low heart rate: 57.7%, high heart rate: 55.8%) and sequential mode (58.0%, 54.7%, p = n.s.). The median absolute difference in Agatston scores between acquisition modes was 14.2% and 9.2%, for the high and low heart rate groups, respectively. Excellent agreement for risk categorization between the two data acquisition modes was found for the high (κ = 0.927) and low (κ = 0.946) heart rate groups. Radiation dose was 48% lower for high-pitch spiral versus sequential acquisitions.

CONCLUSION

Radiation dose for the quantification of coronary calcium can be reduced by 48% when using the high-pitch spiral acquisition mode compared to the sequential mode in participants with a regular high heart rate. CVD risk stratification agreement between the two modes of data acquisition is excellent.