Quantitative CT assessment identifies more heart transplanted patients with progressive coronary wall thickening than standard clinical read.

Background: We sought to compare quantitative coronary CT angiography (CTA) assessment versus standard clinical reading to identify heart transplanted (HTX) patients with progressive coronary wall thickening.

Methods: 35 patients (23 males, age 58 [IQR: 50;61] years) underwent 256-slice coronary CTA at one year and two years after HTX to rule out cardiac allograft vasculopathy (CAV). In addition to the standard clinical read, we quantified total vessel wall volume in all coronaries up to 2-mm luminal diameter. Fixed threshold settings were used to assess calcified (>350 HU) and non-calcified vessel wall components with high- (131-350 HU), intermediate- (75-130 HU) and low-attenuation (<75 HU).

Results: Total lumen volume did not change between baseline and follow-up studies (p = 0.59). Total vessel wall volume showed significant increase (464 [IQR: 338; 570] vs. 563 [IQR: 345; 717] mm, p < 0.001). The volume of high-, intermediate and low-attenuation non-calcified wall components showed progression (332 [IQR: 217;425] vs. 385 [IQR: 238;489], 40 [IQR: 12;48] vs. 59 [IQR: 16;83] and 18 [IQR: 4;21] vs. 46 [IQR: 6;41] mm, respectively, p < 0.05 all), while calcified volume did not change between baseline and follow-up CTAs (72 [IQR: 16;127] vs. 72 [IQR: 29;102] mm, p = 0.73). Quantitative analysis identified more patients with progressive coronary wall thickening (≥10% cut-off) than standard clinical read (11 vs. 22, p = 0.01).

Conclusion: Quantitative coronary wall assessment is feasible with coronary CTA in HTX patients. Coronary wall thickening within the first two years after HTX is mainly attributable to non-calcified lesion components and might be an early sign of CAV.