Prevalence of Aortoiliac Aneurysms in Solid Organ Transplant Recipients Using the National Inpatient Sample Database

Objective: Single-center studies have suggested that solid organ transplant recipients are at increased risk for arterial aneurysms. Moreover, they describe a more aggressive natural history with increased rates of expansion and rupture. In this exploratory analysis, we aim to assess the frequency of arterial aneurysms in solid organ transplant recipients using a large-scale national database.

Methods: We queried the National Inpatient Sample (NIS) dataset from 2016 to 2020 using International Classification of Disease, Tenth Revision, Clinical Modification (ICD-10-CM) codes to identify patients with solid organ transplants. We calculated the prevalence of aortoiliac aneurysms by organ transplant type and performed 1:1 propensity score matching to compare aneurysm rates between transplant recipients and non-transplant patients. Additionally, we used a multivariable model to determine whether the observed aneurysm frequency was due to the transplant intervention or attributable to variable baseline characteristics of the groups.

Results: A retrospective analysis of the NIS database identified 34,920,964 non-transplant patients and 34,288 transplant recipients. Among the transplant cohort, kidney transplant patients made up the largest group at 57.5%. The median age of the transplant group was 55 years, with a predominance of male patients and a low smoking rate of 2.19%. The overall frequency of aortoiliac aneurysms in the transplant population was 0.48%. Specifically, the prevalence of thoracic aortic aneurysms (TAA), abdominal aortic aneurysms (AAA), and iliac artery aneurysms (IAA) was 0.2%, 0.19%, and 0.06%, respectively. Thoracic organ transplant recipients had a higher frequency of aortoiliac aneurysms compared to those with abdominal organ transplants. The frequencies of aortoiliac aneurysms were 0.81% in heart transplant patients, 1.37% in single lung recipients, 0.91% in double lung recipients, 0.42% in liver recipients, and 0.42% in kidney recipients. Additionally, the frequency of AAA was 0.42% in heart transplant recipients and 0.51% in single lung transplant recipients.

Conclusions: As transplant patient survival continues to improve, monitoring for comorbid conditions will become increasingly important. Given the limited availability of organs and importance of post-transplant care, the observed prevalence of aortoiliac aneurysms in heart, lung, and liver transplant recipients highlights the need for enhanced screening, and surveillance. Further studies are required to better understand the rates of aneurysm expansion and rupture in solid organ transplant recipients.