What is the clinical evidence from this study?

Study design: Other. Population: Diffuse coronary artery disease (DCAD) and metabolic syndrome (n=18). Intervention: High fat atherogenic diet vs. Baseline measurements and lean diet control. Primary outcome: Lumen cross-sectional area (CSA) of the left anterior descending (LAD) artery at 4 months (p=0.006).

December 3, 2014IJC Heart & Vasculature9 citationsOpen Access

Compensatory enlargement of Ossabaw miniature swine coronary arteries in diffuse atherosclerosis

JCJenny S. Choy TLTong Luo YHYunlong Huo

Key Result

A high fat atherogenic diet induced compensatory enlargement of coronary arteries in Ossabaw swine, increasing the left anterior descending artery lumen cross-sectional area by 25.8% at 4 months.

Structured PICO

Does a high fat atherogenic diet induce compensatory enlargement of coronary arteries in a metabolic syndrome animal model with diffuse coronary artery disease?

Population

Ossabaw miniature pigs (n=13 total; Group I n=6, Group II n=7) fed a high fat atherogenic diet as a metabolic syndrome animal model with diffuse coronary artery disease

Intervention

High fat atherogenic diet for 4 months (Group I) or 12 months (Group II)

Comparator

Baseline measurements (for Group I)

Outcome

Lumen cross-sectional areas (CSA) of the left anterior descending (LAD), left circumflex (LCX) and right coronary (RCA) arteries measured by IVUS and CCTAsurrogate

This study demonstrates compensatory enlargement (the Glagov phenomenon) of coronary arteries in a metabolic syndrome animal model with diffuse coronary artery disease in the absence of severe focal stenosis.

Main Result

Absolute Event Rate: 7.2% vs 5.8%

p-value: p=0.006

Limitations

Animals developed cardiac arrest during CCTA imaging at 8 months, precluding longitudinal data beyond 4 months.
Measurements at 12 months were made in a different group of animals.
Body weight-matched Yorkshire domestic pigs were used as the control group, which is a different species.
Difficulties in perfectly matching single cross-sectional areas at different time points between IVUS and CCTA.
The atherosclerosis progression was evaluated over a relatively short period of time.

Abstract

Studies in human and non-human primates have confirmed the compensatory enlargement or positive remodeling (Glagov phenomenon) of coronary vessels in the presence of focal stenosis. To our knowledge, this is the first study to document arterial enlargement in a metabolic syndrome animal model with diffuse coronary artery disease (DCAD) in the absence of severe focal stenosis. Two different groups of Ossabaw miniature pigs were fed a high fat atherogenic diet for 4 months (Group I) and 12 months (Group II), respectively. Group I (6 pigs) underwent contrast enhanced computed tomographic angiography (CCTA) and intravascular ultrasound (IVUS) at baseline and after 4 months of high fat diet, whereas Group II (7 pigs) underwent only IVUS at 12 months of high fat diet. IVUS measurements of the left anterior descending (LAD), left circumflex (LCX) and right coronary (RCA) arteries in Group I showed an average increase in their lumen cross-sectional areas (CSA) of 25.8%, 11.4%, and 43.4%, respectively, as compared to baseline. The lumen CSA values of LAD in Group II were found to be between the baseline and 4 months values in Group I. IVUS and CCTA measurements showed a similar trend and positive correlation. Fractional flow reserve (FFR) was 0.91±0.07 at baseline and 0.93±0.05 at 4 months with only 2.2%, 1.6% and 1% stenosis in the LAD, LCX and RCA, respectively. The relation between percent stenosis and lumen CSA shows a classical Glagov phenomenon in this animal model of DCAD.

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