No study has been able to prove long-term benefit of regular imaging follow-up after abdominal aortic aneurysm repair by means of endoprosthesis implantation. This is important because the costs for these studies are high, which should be added to potential radiation and contrast morbidity.
This work sought to characterize the association between post-endovascular abdominal aortic aneurysm repair imaging frequency and long-term survival.
Minimum appropriate imaging follow-up was defined as a computerized tomography (CT) scan or ultrasound of the abdomen within 90 days of the procedure, as well as every 15 months thereafter. A multivariate analysis was conducted to determine the association between compliance with minimum appropriate imaging follow-up over time and all-cause mortality.
The study enrolled 4988 patients treated with an endoprosthesis, and the mean follow-up was 3.4 years. Ninety-day mortality was 1.6%. Among those who survived over 90 days, 87% (n = 4251 of 4902) underwent at least one CT scan or ultrasound of the abdomen within 3 months, but only 58% (n = 2859 of 4902) came back afterwards to meet minimum appropriate imaging follow-up criteria.
Infrequent imaging correlated with lower follow-up by an interventional cardiologist or the vascular surgeon who performed the implantation, but not with infrequent primary care. Patients continued visiting their primary care physician, who did not refer them to specialists in a timely manner for minimum appropriate follow-up for their abdominal aortic aneurysm.
Consistently meeting minimum appropriate follow-up criteria was associated with a lower mortality rate when compared with patients who did not undergo a scan within 90 days (hazard ratio [HR]: 0.82; 95% confidence interval [CI]: 0.69-0.96; p = 0.014), or when compared with patients who underwent a first imaging follow-up within 90 days but missed subsequent follow-up instances (HR: 0.78; 95% CI: 0.68-0.91; p = 0.001).
The longer the patients remained within the minimum appropriate follow-up protocol, the lower the mortality rates.
These data support efforts to improve long term follow-up of patients who receive an endoprosthesis during infrarenal aortic aneurysm repair.
The lower mortality rates observed with regular follow-up after prosthesis implantation can be partially explained by imaging studies. Imaging follow-up may actually be a subrogated endpoint, and reduced mortality may be a consequence of, for example, better control of cardiovascular risk factors, or a change in lifestyle after the procedure.
Patients who disregarded the follow-up still visited their primary care physician regularly, which means that there is an opportunity to improve communication with these physicians in order to obtain adequate imaging follow-up.
Original title: The Impact of Compliance with Imaging Follow-up on Mortality After Endovascular Abdominal Aortic Aneurysm Repair: A Population Based Cohort Study.
Reference: C. de Mestral et al. Eur J Vasc Endovasc Surg (2017). Article in press.
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