A randomized, placebo-controlled trial of doxycycline after endoluminal aneurysm repair

Study enrollment data. Inclusion and exclusion criteria for enrollment are as listed at the conclusion of the study. During the first year of enrollment, the maximal aortic diameter necessary for enrollment was 5.0 cm; this resulted in most of the anatomic exclusions. After randomization, but before dispensing the study medications we had four withdrawals: one developed a postoperative ileus and was unable to take the medication. One patient had an open abdominal aortic aneurysms (AAA) repair, and one patient from each group decided not to accept the study medications after surgery and withdrew. After the medications were dispensed, we had an additional 11 patients without 6 month follow-up. Two (1 doxycycline and 1 placebo) patients withdrew claiming medication gastrointestinal (GI) side effects, 4 developed other illnesses and declined further participation, and 2 withdrew without stating a reason, 1 person withdrew due to a change in insurance coverage and did not return to our facility, 1 patient in the placebo group died from complications of chronic obstructive pulmonary disorder, and there was 1 patient whom we could not contact and was lost to subsequent follow-up.

Correlation between pre-operative matrix metalloproteases (MMP)-9 and MMP-2 and maximum aortic diameter. Although the adjusted correlation coefficient (adj. R²) for MMP-9 is considerably greater than that for MMP-2, circulating levels of both enzymes significantly correlate with the magnitude of aneurysmal dilatation.

Effect of doxycycline treatment on maximal aneurysm diameter change after endoluminal exclusion of an abdominal aortic aneurysm. Change in maximal diameter was calculated as a percentage change in the maximum infrarenal aortic diameter between the 1 and 6 month computed tomography (CT) scans. Patients with evidence of a type II endoleak on the 6-month CT follow-up were excluded from this analysis. Doxycycline treatment resulted in a significantly greater decrease in maximal aneurysm size among the combined group of AneuRx and Excluder treated patients (P < .05).

Effect of doxycycline treatment on aortic neck diameter among patients with Excluder endograft. In the placebo treated group all aortic necks significantly increased in diameter between the preoperative and 6-month computed tomography (CT) scan measures. Among the patients treated with an Excluder endograft, doxycycline prevented this increase in aortic neck diameter. The treated patients demonstrated a significantly smaller increase in aortic diameter than the untreated patients for this sub-group (P < .05). Data is expressed as a percentage of the aortic neck diameter as measured on cross-sectional imaging relative to the nominal endograft diameter (percentage oversized).

Effect of doxycycline therapy on the circulating levels of matrix metalloproteases (MMP)-9. The mean levels of plasma MMP-9 are plotted before and at all follow-up intervals after placement of an aortic endograft. While the surgical procedure caused an initial increase in plasma MMP-9, these levels decreased over the first postoperative month in both groups. While plasma MMP-9 subsequently increased by 6 months in the placebo treated patients, doxycycline treatment resulted in a continued decrease of circulating MMP-9 in this interval. At 6 months, plasma MMP-9 decreased significantly below preoperative levels in the doxycycline treated group (P < .03), but not in the placebo treated patients. The overall change in MMP-9 during the study was significantly different between treatment groups (P < .009).