Objectives: This study was undertaken: 1) to assess the efficacy of traditional PTCA in affording "optimal" initial dilatation (OID) of coronary stenoses (as assessed by on-line quantitative angiography) defined as a post-procedure residual lumen narrowing < or = 20%; 2) to determine clinical and angiographic correlates of these types of successes.
Background: Recent reports have shown that acute angiographic results achieved by traditional PTCA, resembling those obtainable by elective stenting, carry low risks of restenosis. However, safety and the ability of conventional PTCA to consistently provide acute stent-like results are still practically unknown.
Patients and methods: Using a "standardized" procedural protocol intended to optimize acute angiographic results, 878 consecutive non-selected patients, 750 men and 128 women aged 29-78 years (mean 60.5 yrs) underwent PTCA on 1054 lesions. Compliant balloons reaching nominal dimensions at 6 atm and predicted balloon-artery ratios of 0.92-1.05 (mean 1.02) were used. An inflation pressure of 5 atm was gradually and slowly applied initially (usually sufficient to reach the point of plaque fracture). Inflation times of 60 seconds and step-increases in inflation pressure of 1 atm were subsequently utilized, until a large lumen with smooth contours (the nearest to normal) or any wall damage were detected by angiographic tests performed at each step. Inflations were stopped when, even in the presence of sub-optimal dilatation, the inflation pressure of 14 atm was reached (which usually corresponded to an effective balloon/artery ratio < 1.15).
Results: Overall traditional primary successes were 830 (94.5%) for patients and 1001 (95%) for lesions. Major complications, without mortality, were 24 (2.7%). CABS was necessary in 17 patients (1.9%) while acute myocardial infarction occurred in 7 patients (0.8%). OID was obtained in 65.4% of the treated lesions: 77.9% in type A, 73.9% in B1, 54.0% in B2 and 32.5% in C lesion subgroups of the AHA/ACC classification scheme. Multivariate analysis showed that no clinical variables significantly influenced OID. Lesion-related variables such as chronic occlusion, diffuse disease, length > 10 mm, heavily calcified and markedly angulated lesions emerged as (negative) determinants of success.
Conclusions: Acute stent-like angiographic results are obtainable by conventional PTCA in a consistent percentage of eligible coronary lesions. Following a safe modality of balloon-stress application in performing angioplasty, probability of safely achieving OID of coronary stenoses is related to specific angiographic lesion characteristics.