Mark Webster

Results of percutaneous coronary angioplasty in patients < 40 years of age

This study examined factors influencing the outcome of percutaneous transluminal coronary angioplasty (PTCA) in patients <40 years of age. We followed 86 patients (mean age 37 years) treated from 1982 to 1994. The primary procedural success was 90%. At follow-up of 83 patients (97%) at a mean of 48 +/- 33 months (range 5 to 147), there had been 3 late deaths. Actuarial survival at 5 and 10 years was 95% and 91%, respectively. At review only 5% of patients had class III angina and no patient had class IV angina. Repeat revascularization (PTCA alone in 21 [25%], surgery in 8 [10%], or both in 10 [12%] patients) was performed for restenosis in 29 patients (35%) and for disease progression at other sites in 10 patients (12%). On multivariate analysis, a history of diabetes mellitus (p <0.02) was the only factor associated with death or a subsequent cardiovascular event (myocardial infarction, stroke, or hospital admission with unstable angina). At follow-up, 20 patients (24%) still smoked, 64 (77%) had a total cholesterol level > or = 200 mg/dl, 20 (24%) had a body mass index > or = 30, and 15 (18%) were not taking aspirin. In conclusion, PTCA in adults <40 years of age has excellent early results with a low morbidity and mortality. The medium-term prognosis and control of symptoms was good, although by 5 years, further revascularization was required in almost half of the patients.

Long and short of optimal stent design

The ideal stent must fulfil a broad range of technical requirements. Stents must be securely crimped onto the delivery balloon and, in this form, must have a low profile and be sufficiently flexible to facilitate deliverability to the lesion site without distortion or displacement. Following expansion, stents must exert sufficient radial force on the vessel wall to overcome lesion resistance and elastic recoil. To achieve an optimal lumen diameter, the lesion must be uniformly and adequately scaffolded, with minimal tissue prolapse between struts but without compromising side-branch access. Furthermore, the deployed stent must conform to the vessel curvature to minimise vessel distortion, particularly at the stent edges. Radio-opacity is also important to guide safe positioning, adequate deployment and postdilataion and to permit assessment of optimal stent expansion. Equally though, the stent lumen must also be sufficiently visible to allow radiographic assessment of flow dynamics and restenosis. Efforts to optimise one characteristic of stent design may have detrimental effects on another. Thus, currently available stents all reflect a compromise between competing desirable features and have subtle differences in their performance characteristics. Striving to achieve stents with optimal deliverability, conformability and radial strength led to a reduction in longitudinal strength. The importance of this parameter was highlighted by complications occurring in the real-world setting where percutaneous coronary intervention is often undertaken in challenging anatomy. This review focuses on aspects of stent design relevant to longitudinal strength.