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 tes ting to detect restenosis after percutaneous transluminal coronary angiopla sty (PTCA). However, a metaanalysis of these studies has not been performed . OBJECTIVES: To pool the results of studies examining the diagnostic abiliti es of exercise treadmill testing (ETT), stress nuclear imaging and stress e chocardiographic 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 ex amining post-PTCA functional testing for the diagnosis of restenosis. The E nglish language literature was examined for the years 1975 to 2000. Appropr iate articles were identified, and their references were examined to identi fy additional studies. The sensitivities and specificities of these studies were then pooled and Bayes' theorem was used to examine the effect of sten ting on the diagnostic abilities of post-PTCA functional resting. 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%) f or the identification of post-PTCA restenosis. The use of nuclear imaging i ncreases the sensitivity (87%, 95% CI 74% to 100%) and the specificity (78% , 95% CI 74% to 81%). Echocardiographic imaging also increases both sensiti vity (63%, 95% CI 15% to 100%) and specificity (87%, 95% CI 72% to 100%), T he positive likelihood ratios for ETT alone, nuclear imaging and echocardio graphic imaging were calculated to be 1.94, 3.93 and 4.94, respectively. Co nversely, the negative likelihood ratios were calculated to be 0.71, 0.16 a nd 0.43, respectively. As restenosis rates decline from 30% to 10%, the fal se positive rare 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.