Publications

BACKGROUND

Antithymocyte globulin (ATG) is used as induction therapy after cardiac transplant for enhancing immunosuppression and delaying the initiation of nephrotoxic drugs. It is unknown if ATG induction is associated with decreased coronary plaque progression by intravascular ultrasound (IVUS).

METHODS AND RESULTS

Patients transplanted between March 2010 and December 2012 with baseline and 1-year IVUS were included. All patients transplanted were included in a secondary analysis. Change in plaque progression was measured in a blinded fashion on matched coronary segments and contrasted between patients induced with ATG and those who were not. One hundred and three patients were included in IVUS arms. Mean age at transplant was 55.8 ± 12.6 years, and 33.0% were female. Patients induced with ATG were more sensitized (54.3% versus 14.3%). Plaque progression was attenuated in patients who received ATG by changes in maximal intimal area (1.0 ± 1.2 versus 2.3 ± 2.6 mm(2); P = 0.001), maximal percent stenosis (6.3 ± 7.9 versus 12.8 ± 12.3%; = 0.003), maximal intimal thickness (0.2 ± 0.2 versus 0.3 ± 0.3 mm; P = 0.035), and plaque volume (0.5 ± 0.7 versus 1.0 ± 1.3 mm(3)/mm; P = 0.016). Rapid plaque progression by maximal percent stenosis (≥ 20%) occurred less frequently in the ATG arm (4.3% versus 26.3; P = 0.003). Survival (P = 0.242) and any treated rejection (P = 0.166) were not statistically different between groups. Patients receiving ATG had a higher rate of first-year infection (P = 0.003), perhaps related to increased intravenous antibiotic use immediately postoperatively, and a trend toward more biopsy-proven rejection (P = 0.073).

CONCLUSIONS

Induction therapy with ATG is associated with reduced first-year coronary plaque progression as assessed by IVUS, despite an increased prevalence of sensitized patients with a trend toward more rejection.

A 48-year-old woman with 40 years of intermittent squeezing chest pain presented with worsening symptoms. Results of an ambulatory electrocardiogram, echocardiogram, and exercise treadmill were unremarkable. Persistent symptoms prompted a computed tomography coronary angiogram (CTCA) that revealed mid-left anterior descending artery myocardial bridging (MB) that was not physiologically significant by exercise single-photon emission CT. Conservative treatment was pursued. Anatomic MB is prevalent in a large proportion of the general population and are increasingly identified by CTCA. The majority are benign, physiologically significant bridging is uncommon, but accelerated proximal atherosclerosis can occur. b-blockers and nondihydropyridine calcium-channel blockers are the primary treatment options, with surgical myomectomy, coronary artery bypass, and stenting reserved for patients refractory to medical therapy with demonstrable ischemia. Head-to-head evaluation of nonpharmacologic therapies is needed. Intracoronary techniques provide simultaneous anatomical and physiological assessment but CTCA fractional flow reserve and hybrid positron emission tomography with concomitant spatial imaging systems are evolving as noninvasive alternatives.