ORIGINAL ARTICLES   

International Angiology 1999 March;18(1):52-7

Copyright © 2000 EDIZIONI MINERVA MEDICA

Impaired results of a randomised double blinded clinical trial of propranolol versus placebo on the expansion rate of small abdominal aortic aneurysms

Lindholt J. S., Henneberg E. W., Juul S., Fasting H.

From the Department of Vascular Surgery, Hospital of Viborg * Institute of Epidemiology and Social Medicine, University of Aarhus, Denmark

Background. To study the pro­pran­o­lol treat­ment of small abdom­i­nal aor­tic aneu­rysms (AAA) con­cern­ing inten­tion to treat, side ­effects, and inhi­bi­tion of expan­sion.
Methods. Design: Two-year last­ing pros­pec­tive ran­dom­ised dou­ble-blind­ed inter­ven­tion trial. Setting: Hospital-based mass screen­ing for AAA with annu­al ambu­la­to­ry con­trol of small AAA. Participants: Of 122 screen­ing-diag­nosed small AAA, 51 (42%) were exclud­ed ­because of con­tra­in­di­ca­tions or ­present beta-block­age, and 17 ­refused par­tic­i­pa­tion. Thus, 54 (44.3%) were includ­ed. Intervention: Participants were ran­dom­ised to 40 mg pro­pran­o­lol twice a day or pla­ce­bo. Measures: The same ­observed was used to fol­low-up AAA-expan­sion, side ­effects, qual­ity of life (QL), bran­chi­al and ankle blood pres­sure (ABI), and pul­mo­nary func­tion (FEV1 and FVC).
Results. Sixty per­cent in the pro­pran­o­lol group, and 25% in the pla­ce­bo group ­dropped out, main­ly ­caused by dysp­noea in the pro­pran­o­lol group (RR=1.74, 95% C.I.: 1.06-2.86). Five (16.7%) died in the pro­pran­o­lol group, while 1 (4.2%) died in the pla­ce­bo group (RR=1.6 (1.02-2.51)). Furthermore, ­decreased pul­mo­nary func­tion, ABI, and QL was ­noticed in the pro­pran­o­lol group. Consequently, the trial was ­stopped after two years.
Ninety-five percent of the meas­ure­ments of the AAA were meas­ured with­in 2 mm vari­a­tion. If expan­sion was ­defined as above 2 mm annu­al­ly, the rel­a­tive risk of expan­sion in the pla­ce­bo group was 1.17 (0.74-1.85), and 2.44 (0.88-6.77) among the non-drop-outs.
Conclusions. Only 22% of small screen­ings-diag­nosed AAA were treat­able with pro­pran­o­lol for two years. Consequently, only large scale stud­ies are ­capable of show­ing poten­tial minor inhi­bi­tion of expan­sion by pro­pran­o­lol. However, wheth­er such treat­ment ever ­becomes eth­i­cally accept­able is debat­able.