Effect of the ratio of coronary arterial lumen volume to left ventricle myocardial mass derived from coronary CT angiography on fractional flow reserve

BACKGROUND

We hypothesize that in patients with suspected coronary artery disease (CAD), lower values of the ratio of total epicardial coronary arterial lumen volume to left ventricular myocardial mass (V/M) result in lower fractional flow reserve (FFR).

METHODS

V/M was computed in 238 patients from the NXT trial who underwent coronary computed tomography angiography (CTA), quantitative coronary angiography (QCA) and FFR measurement in 438 vessels. Nitroglycerin was administered prior to CT, QCA and FFR acquisition. The V/M ratio was quantified on a patient-level from CT image data by segmenting the epicardial coronary arterial lumen volume (V) and the left ventricular myocardial mass (M). Calcified and noncalcified plaque volumes were quantified using semi-automated software.

RESULTS

The median value of V/M (18.57 mm³/g) was used to define equal groups of low and high V/M patients. Patients with low V/M had greater diameter stenosis by QCA, more plaque and lower FFR (0.80 ± 0.12 vs. 0.87 ± 0.08; P < 0.0001) than those with high V/M. A total of 365 vessels in 202 patients had QCA stenosis ≤50% and measured FFR. In these patients, those with low V/M had higher percent diameter stenosis by QCA, greater total plaque volume and lower FFR (0.81 ± 0.12 vs. 0.88 ± 0.07; P < 0.0001) than those with high V/M. In multivariate logistic regression analysis, V/M was an independent predictor of FFR ≤0.80 (all p-values < 0.001).

CONCLUSIONS

Patients with a low V/M ratio have lower FFR overall and in non-obstructive CAD, independent of plaque measures.

Offering integrated care for HIV/AIDS, diabetes and hypertension within chronic disease clinics in Cambodia

PROBLEM

In Cambodia, care for people with HIV/AIDS (prevalence 1.9%) is expanding, but care for people with type II diabetes (prevalence 5-10%), arterial hypertension and other treatable chronic diseases remains very limited.

APPROACH

We describe the experience and outcomes of offering integrated care for HIV/AIDS, diabetes and hypertension within the setting of chronic disease clinics.

LOCAL SETTING

Chronic disease clinics were set up in the provincial referral hospitals of Siem Reap and Takeo, 2 provincial capitals in Cambodia.

RELEVANT CHANGES

At 24 months of care, 87.7% of all HIV/AIDS patients were alive and in active follow-up. For diabetes patients, this proportion was 71%. Of the HIV/AIDS patients, 9.3% had died and 3% were lost to follow-up, while for diabetes this included 3 (0.1%) deaths and 28.9% lost to follow-up. Of all diabetes patients who stayed more than 3 months in the cohort, 90% were still in follow-up at 24 months.

LESSONS LEARNED

Over the first three years, the chronic disease clinics have demonstrated the feasibility of integrating care for HIV/AIDS with non-communicable chronic diseases in Cambodia. Adherence support strategies proved to be complementary, resulting in good outcomes. Services were well accepted by patients, and this has had a positive effect on HIV/AIDS-related stigma. This experience shows how care for HIV/AIDS patients can act as an impetus to tackle other common chronic diseases.