[Evaluation of indications for PTCA]

Rating the indications for invasive cardiac procedures often is regarded as one key method for quality assessment in cardiology. The aim of this study was to evaluate the validity of the method proposed by the RAND Corporation and the University of California, Los Angeles, appropriateness and necessity rating. Two hypotheses were tested: 1. The acute and long-term benefit of PTCA is less clearly in cases rated "uncertain" than in cases rated "appropriate" or "necessary", and 2. in cases rated "necessary", successful PTCA improves the patients long-term prognosis, since RAND's definition of "necessary" implies that a successful PTCA will avert major harm from this patient.

Five hundred and one consecutive patients dilated between 1981 and 1984 were included.

Age 52.5 +/- 8.2 years, male gender 87.0%, Canadian Heart Classification (CHC) class I or II 40.5%, positive and extremely positive stress test 54.4% and 33.3%, single vessel disease 72.5%. The long-term follow-up was determined by questionnaire 91 +/- 21 months after PTCA, and a complete 5-year follow-up was available in 95.4% of all patients.

According to RAND's 1991 published criteria, 1.0% of all indications were rated "inappropriate", 21.4% "uncertain", 27.1% "appropriate", and 50.5% "necessary". Before PTCA, patients rated "uncertain" were less symptomatic and had a higher exercise capacity than patients rated "necessary" (CHC I or II: 85.0% vs. 8.7%, p < 0.001; 693 +/- 214 vs. 520 +/- 251 watts*min, p < 0.001). Following PTCA, "uncertain" patients reported less often a lasting symptomatic improvement or freedom of symptoms than "necessary" patients (63.9% vs. 76.3%, p = n.s.), and they experienced no relevant improvement in exercise capacity (10 +/- 263 vs. 139 +/- 308 watts*min, p < 0.05). The acute success rate was significantly lower for patients who underwent PTCA for indications rated "revascularization necessary" or "CABG necessary", p < 0.03. This resulted in a high rate of CABG within the first year for patients with these rating (29.0% and 36.1%, compared to 15.0% to 20.6% in cases rated "uncertain", "appropriate", or "PTCA necessary", p < 0.02). Only in patients with the rating "PTCA necessary" (n = 184), a significant difference in long-term survival was observed between successful and unsuccessful uncomplicated cases (5-year-survival-probability 97.8 +/- 1.3% vs. 85.5 +/- 6.0%, p < 0.001). In contrast, "uncertain" cases (n = 107) had a 5-year-survival-probability of 94.8 +/- 2.5% following successful and 94.4 +/- 5.4% following unsuccessful PTCA.

These results are in agreement with both hypotheses and therefore support the validity of RAND's 1991 appropriateness and necessity criteria for PTCA in a historic series of patients. Thus, even if these particular ratings may be outdated today, the technique of appropriateness and necessity rating is expected to be a useful and valid tool for quality assessment in PTCA.