The effects of improved hemodynamics on aortic dimensions in patients undergoing heart transplantation

Abstract

Purpose: Retrospective studies have demonstrated an accelerated growth rate of abdominal aortic aneurysms in heart transplant patients. This prospective study was undertaken to define the relationship between cardiac hemodynamics and posttransplant aortic dilation.Methods: Sixty-eight patients undergoing heart (n = 60) or heart-lung (n = 8) transplantation were prospectively evaluated with abdominal ultrasonography before transplantation and annually after transplantation. Risk factors implicated in aneurysm growth, including age, indication for transplantation, immunosuppression, posttransplantation hypertension, and abdominal aortic dimension before transplantation were recorded. All patients underwent annual coronary artery catheterization and multiple gated acquisition scanning.Results: Thirty-seven patients (54%) had no change in aortic diameter after transplantation (pretransplantation and posttransplantation diameter = 1.8 ± 0.3 cm), over a mean follow-up period of 28 ± 14 months. In the remaining 31 (46%) patients, aortic diameter increased by 0.5 ± 0.6 cm over 31 ± 15 months (p < 0.05). Four (6%) of these 31 patients had abdominal aortic aneurysms (mean aortic diameter = 5.0 ± 0.8 cm). The mean increase in aortic diameter among these 4 patients was 1.8 ± 0.2 cm (annual rate of growth = 0.96 ± 0.3 cm/year). Patients experiencing an increase in aortic dimension after transplantation had significantly lower (p < 0.005) pretransplantation ejection fractions (17.1% ± 10.5% vs 28.6% ± 18.1%) and, as a consequence, significantly greater (p < 0.05) increases in their ejection fractions after transplantation compared with patients with stable aortic dimensions (42.7% ± 12.6% vs 31.8% ± 18.0%).Conclusions: Of 68 heart transplant patients prospectively evaluated, aortic diameter increased in 31 (46%); new aneurysms developed in four of these patients. Greater incremental increases in cardiac ejection fraction were significant correlates with aortic enlargement.