Yngvar Myreng

Stenting in small coronary arteries (SISCA) trial. A randomized comparison between balloon angioplasty and the heparin-coated beStent.

OBJECTIVES The purpose of this study was to assess the clinical and angiographic benefits of elective stenting in coronary arteries with a reference diameter of 2.1 to 3.0 mm, as compared with traditional percutaneous transluminal coronary angioplasty (PTCA). BACKGROUND The problems related to small-vessel stenting might be overcome using modern stents designed for small vessels, combined with effective antiplatelet therapy. METHODS In five centers, 145 patients with stable or unstable angina were randomly assigned to elective stenting treatment with the heparin (Hepamed)-coated beStent or PTCA. Control angiography was performed after six months. The primary end point was the minimal lumen diameter (MLD) at follow-up. Secondary end points were the restenosis rate, event-free survival and angina status. RESULTS At follow-up, there was a trend toward a larger MLD in the stent group (1.69 +/- 0.52 mm vs. 1.57 +/- 0.44 mm, p = 0.096). Event-free survival at follow-up was significantly higher in the stent group: 90.5% vs. 76.1% (p = 0.016). The restenosis rate was low in both groups (9.7% and 18.8% in the stent and PTCA groups, respectively; p = 0.15). Analyzed as treated, both the MLD and restenosis rate were significantly improved in patients who had stents as compared with PTCA. CONCLUSIONS In small coronary arteries, both PTCA and elective stenting are associated with good clinical and angiographic outcomes after six months. Compared with PTCA, elective treatment with the heparin-coated beStent improves the clinical outcome; however, there was only a nonsignificant trend toward angiographic improvement.

Left ventricular filling at elevated diastolic pressures: Relationship between transmitral Doppler flow velocities and atrial contribution

The relationship between transmitral Doppler blood flow velocities and atrial contribution to left ventricular (LV) filling was investigated in seven open-chest dogs. At LV filling pressures greater than 15 to 20 mm Hg, LV volume approaches a maximum. Thus we hypothesized that when LV pressure before the onset of atrial systole exceeds this level, the atrial contribution would decrease and the ratio between peak early (E) and atrial-induced (A) mitral velocities would increase. Atrial contribution was measured as LV diameter increase during atrial contraction expressed as a percentage of the total LV diameter change during diastole (sonomicrometry). When left ventricular end-diastolic pressure (LVEDP) was progressively increased from 10 +/- 1 (mean +/- standard deviation) to 28 +/- 3 mm Hg by intravenous saline solution, the atrial contribution decreased from 34 +/- 14% to 8 +/- 10% (p less than 0.001). Concomitantly the A velocity decreased from 39 +/- 7 to 24 +/- 8 cm.sec-1 (p less than 0.01), and the E/A ratio increased from 1.8 +/- 0.3 to 3.6 +/- 1.5 (p less than 0.001). The E/A ratio and the atrial contribution were constant until LVEDP exceeded 17 to 20 mm Hg, at which level marked changes in both parameters were noted. Thus when LV filling pressure was increased, the E/A ratio increased, indicating a filling shift towards early diastole. The reduced atrial contribution during increased preload was explained by the curvilinear shape of the LV pressure-volume curve. At markedly elevated filling pressures, near-maximum LV diameter was achieved before atrial contraction; hence the atrial contribution decreased and the E/A ratio increased.(ABSTRACT TRUNCATED AT 250 WORDS)

Sustained benefit of Stenting Chronic Coronary occlusion : Long-term clinical follow-up of the Stenting in Chronic Coronary occlusion (SICCO) study

OBJECTIVES This study assessed the long-term clinical outcome of stenting chronic occlusions. BACKGROUND In the Stenting in Chronic Coronary Occlusion (SICCO) study, patients were randomized to additional stent implantation (n = 58) or not (n = 59) after successful recanalization and dilation of a chronic coronary occlusion. Palmaz-Schatz stents were used with full anticoagulation. The previously published 6-month angiographic follow-up results showed reduction of the restenosis rate from 74% to 32%. METHODS The primary end point was the occurrence of major adverse cardiac events (cardiac death, lesion-related acute myocardial infarction, repeat lesion-related revascularization or angiographic documentation of reocclusion). RESULTS Late clinical follow-up was obtained in all patients at 33 +/- 6 months. Major adverse cardiac events occurred in 14 patients (24.1%) in the stent group compared with 35 patients (59.3%) in the percutaneous transluminal coronary angioplasty (PTCA) group (odds ratio 0.22, 95% confidence interval 0.10 to 0.49, p = 0.0002). Target vessel revascularization (including failed PTCA attempts) was performed in 24% of the stent group and in 53% of the PTCA group (p = 0.002). There were no events in the stent group after 8 months, whereas events continued to occur in the PTCA group. By multivariate analysis, allocation to the PTCA group, left anterior descending coronary artery lesion and lesion length were significantly related to the development of major adverse cardiac events. CONCLUSIONS These data demonstrate the long-term safety and clinical benefit of stenting recanalized chronic occlusions. There is a continued risk of late clinical events related to nonstented lesions. Implantation of an intracoronary stent should therefore be considered after successful opening of a chronic coronary occlusion.

Reproducibility of cardiac stroke volume estimated by Doppler echocardiography

Doppler echocardiography was used to measure cardiac stroke volume in 10 patients with coronary artery disease who were treated with cardioactive drugs. Stroke volume estimates were determined at the aortic orifice by multiplying area by systolic velocity integral measured both from the suprasternal and the apical approach. Recordings were done independently by 2 experienced observers on the same day and repeated once after 1 to 21 days. Analysis of variance showed that no systematic differences were introduced by the 2 observers and Doppler approaches or by measuring on different days. The coefficient of variation between any pair of measurements in each patient was 9%. This variability is probably a result of the method or spontaneous fluctuations of the stroke volume and not of the varying recording conditions. The ultrasonic method detects day-to-day changes of cardiac stroke volume larger than 20% with a probability greater than 0.95.

Reproducibility of quantitative coronary analysis, Assessment of variability due to frame selection, different observers, and different cinefilmless laboratories.

Because of limited storage capacity for digital images, angiographic laboratories without cinefilm are dependent on locally performed quantitative coronary angiography (QCA) in clinical studies. In the present study the intra-and interobserver variability, as well as variability between different laboratories and variability due to frame selection was analyzed. A total of 20 coronary lesions were studied in two different digital laboratories 12±8 days apart. Images were analyzed on-line and after being transferred to a Cardiac Work Station (CWS). There was no significant difference between the measurement situations. For minimal luminal diameter (MLD) precision (SD of signed errors) ranged from 0.12 mm to 0.20 mm, for reference diameter (RD) from 0.15 mm to 0.28 mm, and for percent diameter stenosis (DS) from 4.2% to 5.8%. Overall relative precision was obtained by normalizing the QCA parameters, and was 11.9% for MLD, 7.0% for RD and 8.5% for DS (p<0.001, RD and DS compared to MLD). The overall variability in the interobserver and in the interlaboratory comparisons was 11.2% and 10.4%, respectively (n.s.) (n.s.). Thus the variability of QCA performed in cinefilmless, digital laboratories is small, and within a range making it an useful tool for clinical practice and group comparisons in clinical studies. However, the error range of QCA measurements must be taken into consideration when judging results from individual patients.

Effects of verapamil on left ventricular relaxation and filling dynamics in coronary artery disease: A study by pulsed Doppler echocardiography

The effect of verapamil on left ventricular diastolic function in coronary artery disease was assessed by Doppler echocardiography of transmitral flow velocities in 20 patients. At baseline, isovolumic relaxation time was prolonged compared with that in 18 age-matched normal subjects (95 +/- 13 msec versus 74 +/- 12 msec, p less than 0.001), but decreased to 80 +/- 14 msec (p less than 0.001) after treatment. The ratio between early and atrial-induced transmitral velocities (E/A-ratio) at baseline was lower in patients than in normal subjects (1.1 +/- 0.2 versus 1.4 +/- 0.3, p = 0.01), as was the filling fraction of the first third of diastole (43% +/- 5% versus 50% +/- 4%, p less than 0.001). Verapamil treatment increased the E/A-ratio to 1.3 +/- 0.4 (p less than 0.001) and filling fraction to 45% +/- 4% (p = 0.055) because of increased early filling. No change in systolic performance or heart rate was observed. Thus, coronary artery disease was associated with retarded relaxation and impairment of early filling. However, verapamil treatment enhanced relaxation and induced a filling shift toward early diastole, which indicated improved diastolic performance. The changes probably reflected reduced myocardial ischemia.

Reproducibility of echocardiographic estimates of the area of stenosed aortic valves using the continuity equation

Interobserver variability in echocardiographic estimates of the area of stenosed aortic valves was assessed in 30 consecutive patients. Using the continuity equation, two independent observers calculated the area of stenosis from separate recordings of the diameter of the aortic orifice and the velocity time integral in the left ventricular outflow tract and in the stenotic jet. No significant difference between the observers was noted for any measurement. With respect to the area of stenosis, a high correlation between the observers was found (r = 0.92, P less than 0.001) and the regression line was close to the line of identity. The 95% limits of agreement were less than +/- 0.3 cm2. No discrepancy between the observers was found in the assessment of cases for aortic stenosis less than 0.8 cm2. Regression analyses showed good interobserver agreement also for the diameter of the orifice, the velocity time integrals, and the mean pressure gradient (r greater than 0.90, P less than 0.001). The greatest variability was noted for the diameter of the aortic orifice (95% limits of agreement +/- 1.4 cm2). We conclude that echocardiography enables reproducible estimates of the orificial area of stenosed aortic valves. Changes greater than 0.3 cm2 can be detected with a confidence probability of 95%. The greatest source of error is the measurement of the diameter of the outflow tract at the basal attachments of the aortic leaflets.

Variability of quantitative coronary angiography: an evaluation of on-site versus core laboratory analysis

To assess the validity of locally performed off-line quantitative coronary angiography (QCA) measurement in clinical trials, we carried out a comparative study between on-site QCA analysis and analysis performed at an independent external core laboratory. One local operator analyzed the pre, post and follow-up angiograms of 116 patients participating in the Stenting in Small Coronary Arteries Study (SISCA) prior to final QCA analysis in the core laboratory. The mean values of the reference diameter (RD), minimal lumen diameter (MLD) and diameter stenosis (DS) showed acceptable agreement between study site and core laboratory. However, on the level of individuals the interobserver differences were large, affecting the outcome of restenosis rate significantly, and in a such way that the conclusions in the SISCA trial might have come out differently if a core laboratory had not been used. This emphasizes the importance of using independent core laboratories in coronary interventional trials.

Stenting small coronary arteries using two second-generation slotted tube stents: acute and six-month clinical and angiographic results.

This prospective study assessed the feasibility, safety, as well as clinical and angiographic outcome after 6 months in 96 patients (100 lesions) treated by stent implantation after a suboptimal balloon angioplasty result in coronary arteries < 3 mm and with a lesion length < 25 mm. The lesions were randomized to treatment with BeStent small or NIR‐7. Final quantitative coronary angiography was performed off line. Baseline reference diameter was 2.58 ± 0.22 mm. Complex lesions constituted 52%, and 23% had unstable angina. Angiographic and procedural success was achieved in 98% and 94%, respectively. At follow‐up, 88.5% were free of major adverse cardiac events. The overall restenosis rate was 22.5% (89% angiographic follow‐up). There were no statistically significant differences between the stents regarding predefined endpoints. Thus, provisional stent treatment of small coronary arteries using BeStent small or NIR‐7 is feasible, safe, and has a favorable clinical and angiographic mid‐term outcome. Cathet. Cardiovasc. Intervent. 50:307–313, 2000.

Clinical Benefit of Small Vessel Stenting: One-year Follow-up of the SISCA Trial

Objective : To assess the long-term clinical benefit of elective stenting as compared with percutaneous transluminal coronary angioplasty (PTCA) in small coronary arteries. Design : The Stenting in Small Coronary Arteries (SISCA) trial was a randomized trial comparing elective stenting with PTCA in coronary arteries with a reference diameter of 2.1-3.0 mm. The heparin-coated beStent was used. Control angiography was performed after 6 months, and the patients were followed clinically for 12 months. Results : At 6 months the clinical outcome was significantly better in the stent group as compared with the PTCA group, with an event-free survival in 90.5 and 76.1% ( p = 0.016), respectively. From 6 to 12 months, event-free survival was unchanged in both groups, demonstrating a sustained long-term clinical benefit of elective stenting. Conclusion : Angioplasty in small coronary arteries is associated with a favorable clinical outcome after 1 year. The clinical benefit of elective stenting using the Hepamed ® -coated beStent is maintained beyond 6 months, without any tendency towards late events. Thus, elective stenting should be considered as an option when treating small coronary arteries.