Functional Testing for the Detection of Restenosis After Percutaneous Transluminal Coronary Angioplasty: a Meta-analysis

Background: A number of studies have examined the ability of functional testing to detect restenosis after percutaneous transluminal coronary angioplasty (PTCA). However, a meta-analysis of these studies has not been performed.

Objectives: To pool the results of studies examining the diagnostic abilities of exercise treadmill testing (ETT), stress nuclear imaging and stress echocardiographic imaging at six months to detect post-PTCA restenosis. The secondary objective was to examine, through the use of a theoretical model, the impact of stenting on the yield of post-PTCA functional testing.

Patients And Methods: A MEDLINE search was conducted to identify studies examining post-PTCA functional testing for the diagnosis of restenosis. The English-language literature was examined for the years 1975 to 2000. Appropriate articles were identified, and their references were examined to identify additional studies. The sensitivities and specificities of these studies were then pooled and Bayes' theorem was used to examine the effect of stenting on the diagnostic abilities of post-PTCA functional testing.

Results: A pooled analysis showed that ETT alone has a poor sensitivity (46%, 95% CI 33% to 58%) and a moderate specificity (77%, 95% CI 67% to 86%) for the identification of post-PTCA restenosis. The use of nuclear imaging increases the sensitivity (87%, 95% CI 74% to 100%) and the specificity (78%, 95% CI 74% to 81%). Echocardiographic imaging also increases both sensitivity (63%, 95% CI 15% to 100%) and specificity (87%, 95% CI 72% to 100%). The positive likelihood ratios for ETT alone, nuclear imaging and echocardiographic imaging were calculated to be 1.94, 3.93 and 4.94, respectively. Conversely, the negative likelihood ratios were calculated to be 0.71, 0.16 and 0.43, respectively. As restenosis rates decline from 30% to 10%, the false positive rate of stress imaging increases from 37% to 77%.

Conclusions: ETT alone is poorly diagnostic of post-PTCA restenosis, while stress nuclear and stress echocardiographic imaging perform better. However, the value of routine post-PTCA functional testing to detect restenosis is declining because restenosis rates are decreasing.