Comparison of QCA systems

Combining short stent implantation and drug-eluting stenting for routine use yields a low restenosis rate

BACKGROUND

Stent length serves as a predictor of restenosis in use of bare metal stents (BMS). This has been demonstrated in a feasibility study that used a single short BMS implant (<9 mm) in a high proportion of lesions; the study observed a low rate of restenosis.

METHODS

We performed a pilot prospective study to investigate in a series of consecutive patients the immediate and long-term effects of implantation of either 1) a single short BMS for all lesions with low probability of restenosis or 2) a drug-eluting stent (DES) for all other lesions.

RESULTS

The 200 patients studied had 236 coronary artery lesions that were treated with short BMS in 168/236 patients (71.2%) and with DES in 68/236 patients (28.8%). Angiographic success was achieved in 230/236 lesions (97.5%) and procedural success in 194/200 patients (97.0%). Restenosis occurred in 15/153 lesions (9.8%) after short BMS, in 3/62 lesions (4.8%) after DES, and in 18/215 of all lesions (8.4%) angiographically controlled after six to eight months. Target vessel revascularization was performed in 16/218 lesion (7.4%).

CONCLUSION

Most of the coronary artery lesions in this small group of consecutive patients were treated sufficiently with a single BMS implant. This differential approach of treating suitable lesions in medium- to large-sized vessels with a single short BMS device and treating all other lesions with a DES implant resulted in a low incidence of restenosis.

Preservation from left ventricular remodeling by front-integrated revascularization and stem cell liberation in evolving acute myocardial infarction by use of granulocyte-colony-stimulating factor (FIRSTLINE-AMI)

BACKGROUND

Considering experimental evidence that stem cells enhance myocardial regeneration and granulocyte colony-stimulating factor (G-CSF) mediates mobilization of CD34+ mononuclear blood stem cells (MNCCD34+), we tested the impact of G-CSF integrated into primary percutaneous coronary intervention (PCI) management of acute myocardial infarction in man.

METHODS AND RESULTS

Fifty consecutive patients with ST-segment elevation myocardial infarction were subjected to primary PCI stenting with abciximab and followed up for 6 months; 89+/-35 minutes after successful PCI, 25 patients were randomly assigned in this pilot study (PROBE design) to receive subcutaneous G-CSF at 10 microg/kg body weight for 6 days in addition to standard care, including aspirin, clopidogrel, an ACE inhibitor, beta-blocking agents, and statins. By use of CellQuest software on peripheral blood samples incubated with CD45 and CD34, mobilized MNCCD34+ were quantified on a daily basis. With homogeneous demographics and clinical and infarct-related characteristics, G-CSF stimulation led to mobilization of MNCCD34+ to between 3.17+/-2.93 MNCCD34+/microL at baseline and 64.55+/-37.11 MNCCD34+/microL on day 6 (P<0.001 versus control); there was no indication of leukocytoclastic effects, significant pain, impaired rheology, inflammatory reactions, or accelerated restenosis at 6 months. Within 35 days, G-CSF and MNCCD34+ liberation led to enhanced resting wall thickening in the infarct zone of between 0.29+/-0.22 and 0.99+/-0.32 mm versus 0.49+/-0.29 mm in control subjects (P<0.001); under inotropic challenge with dobutamine (10 microg.kg(-1).min(-1)), wall motion score index showed improvement from 1.66+/-0.23 to 1.41+/-0.21 (P<0.004 versus control) and to 1.35+/-0.24 after 4 months (P<0.001 versus control), respectively, coupled with sustained recovery of wall thickening to 1.24+/-0.31 mm (P<0.001 versus control) at 4 months. Accordingly, resting wall motion score index improved with G-CSF to 1.41+/-0.25 (P<0.001 versus control), left ventricular end-diastolic diameter to 55+/-5 mm (P<0.002 versus control), and ejection fraction to 54+/-8% (P<0.001 versus control) after 4 months. Morphological and functional improvement with G-CSF was corroborated by enhanced metabolic activity and 18F-deoxyglucose uptake in the infarct zone (P<0.001 versus control).

CONCLUSIONS

G-CSF and mobilization of MNC(CD34+) after reperfusion of infarcted myocardium may offer a pragmatic strategy for preservation of myocardium and prevention of remodeling without evidence of aggravated restenosis.

Multidetector-row computed tomography vs. angiography and intravascular ultrasound for the evaluation of the diameter of proximal coronary arteries

BACKGROUND

Multidetector-row computed tomography has evolved as a promising method for noninvasive visualization of coronary arteries and detection of coronary artery calcification. We determined the accuracy of computed tomography for measurement of coronary artery lumen diameters in comparison to quantitative coronary angiography and intravascular ultrasound (IVUS).

METHODS

Eighteen patients (4 female, age 62+/-8 years) with known or suspected coronary artery disease were investigated by computer tomography (4x1 mm collimation, rotation time: 500 ms, table feed: 1.5 mm/rotation). Coronary angiography and IVUS were performed in the left anterior descending, left circumflex and right coronary artery according to common standards. Lumen diameters were measured at the origin of the coronary artery and 10, 30 and 50 mm distally. Results of all three techniques were compared.

RESULTS

Only measuring points evaluated by all measuring techniques were included. Thus, 50 diameters could be analyzed. The correlation R between computed tomography and angiography measures was 0.909 (p<0.05) at the origin of the artery, 0.907 (p<0.05) at 10, 0.841 (p<0.05) at 30 and 0.780 (p<0.05) at 50 mm distally. The correlation R between computed tomography and IVUS was 0.934 at the origin (p<0.05), 0.867 at 10 (p<0.05), 0.880 at 30 (p<0.05) and 0.727 at 50 mm (p<0.05).

CONCLUSIONS

Multidetector-row computed tomography is a promising tool to measure the proximal coronary artery diameters with a good correlation to angiographic and IVUS measurements. Multidetector-row computed tomography might become more feasible with improvement of technology, e.g. with 16 row scanners.

Shortening the stent length reduces restenosis with bare metal stents: matched pair comparison of short stenting and conventional stenting

OBJECTIVE

To investigate the effect of reducing stent length on the rate of target lesion restenosis.

DESIGN

In a prospective investigation, acute and long term results of a short stenting procedure were analysed by quantitative angiography and compared with results of a conventional stenting procedure selected according to a matched pairs analysis.

PATIENTS

Short stents were implanted in 400 consecutive patients with 464 lesions and conventional stents in 430 patients. Demographic and lesion characteristics were comparable between groups.

INTERVENTIONS

In short stenting, the shortest stent length to cover only segments with > 30% reduction in vessel diameter was used. In conventional stenting, full coverage of a stenotic vessel segment was intended.

MAIN OUTCOME MEASURES

The mean stent lengths of the short stent group (9.8 (4) mm) and the conventional stent group (16.3 (7) mm) differed significantly (p < 0.0001); all other procedural and angiographic parameters were the same. Procedural success was similar for both groups. Control angiography after six months was conducted in 92% of patients.

RESULTS

Short stenting resulted in both less restenosis (68 of 431 (15.8%)) than conventional stenting (93 of 381 (24.4%), p = 0.007) and less late lumen loss (0.6 (0.6) mm v 0.75 (0.5) mm, p = 0.0001). Residual stenosis (< 45%) in adjacent vessel segments after short stenting did not affect the restenosis rate. Only the implantation of a < or = 9 mm stent predicted the absence of restenosis in a multivariate analysis.

CONCLUSION

Shortening the length of bare metal stents reduces the restenosis rate as compared with conventional stenting.

Short stent implantation for routine use is feasible in a high proportion of coronary interventions and yields a low restenosis rate

Stent length predicts restenosis. The feasibility of using a short stent (<10 mm) routinely was investigated in 331 consecutive patients treated for 424 coronary artery lesions. A single short stent provided suitable coverage and achieved a residual stenosis <30%, with or without predilatation, in 252/424 lesions (59.4%). Longer stents were implanted in 58/424 lesions (13.7%), while only percutaneous transluminal coronary angioplasty was performed in 114/242 lesions (26.9%). Angiographic success and procedural success were achieved in 250/252 lesions (99.2%). Restenosis occurred in 36/231 lesions (15.6%) after short stenting, in 10/53 lesions (18.9%) after long stents, in 21/88 lesions (23.9%) after percutaneous transluminal coronary angioplasty, and in 67/372 lesions (18.0%) controlled angiographically. Only small vessel diameter predicted restenosis after short stenting. Thus, a single short stent implanted directly or after predilatation is sufficient to achieve an acceptable angiographic result in more than in nearly 60% of all treated lesions. Short stenting results in a low restenosis rate.

Angiographic outcome in multivessel disease (GABI II study) using new coronary device interventions and comparison with GABI I trial results

Percutaneous coronary interventions using stents were investigated in patients with multivessel disease. Acute and long-term results were compared with those of the German Angioplasty Bypass Surgery Investigation trial in a prospective multicenter study. The study included 134 patients in whom 277 lesions were treated. Angiographic success and procedural success were achieved in 268 of 277 lesions (97%) and 118 of 134 patients (88%), respectively. Control angiography performed in 90 of 118 eligible patients (76%) exhibited restenosis in 43 of 182 lesions (24%). Multivariate regression analysis found that a diffuse lesion, the lesion and stent length, and the final luminal diameter were predictive for restenosis. Thus, immediate and long-term results of multivessel coronary intervention utilizing stents were improved compared to percutaneous transluminal coronary angioplasty of multivessel lesions. However, there is still need for improvement of long-term results, especially in particular lesion subgroups.

Multislice spiral computed tomography for the detection of coronary stent restenosis and patency

BACKGROUND

Multislice spiral computed tomography (MSCT) has evolved as a new promising method for non-invasive visualization of the coronary arteries and detection of native coronary artery stenosis. We determined the value of MSCT to non-invasively detect significant in-stent restenosis after coronary artery stenting.

METHODS

Twenty patients (age 56.3+/-8.6 years) were investigated by MSCT (4x1 mm cross-sections, 500 ms tube rotation, table feed 1.5 mm/rotation, intravenous contrast agent, retrospectively ECG-gated image reconstruction) at a mean interval of 9.6+/-4.2 months after coronary stent implantation. Results were compared with conventional quantitative coronary angiography (QCA). A total number of 32 stents were studied, four different stent types were evaluated.

RESULTS

QCA showed in-stent restenosis >50% diameter stenosis in five (16%) stents. Using MSCT it was impossible in all stents, irrespective of stent type or diameter, to directly visualize the stent lumen due to partial volume effects and beam hardening. MSCT allowed the visualization of the coronary vessel proximal and distal to the stent. This allowed confirmation of stent patency in 18/18 cases and correct identification of total stent occlusion in two patients.

CONCLUSIONS

MSCT allows no direct visualization of coronary in-stent restenosis, but it correctly differentiates between stent patency and stent occlusion. The reasons are mainly partial volume effects and beam hardening, which are induced by the stent material.

Value of 3D-volume rendering in the assessment of coronary arteries with retrospectively ECG-gated multislice spiral CT

PURPOSE

To assess the diagnostic value and measurement precision of 3D volume rendering technique (3D-VRT) from retrospectively ECG-gated multislice spiral CT (MSCT) data sets for imaging of the coronary arteries.

MATERIAL AND METHODS

In 35 patients, retrospectively ECG-gated MSCT of the heart using a four detector row MSCT scanner with a standardized examination protocol was performed as well as quantitative X-ray coronary angiography (QCA). The MSCT data was assessed on segmental basis using 3D-VRT exclusively. The coronary artery diameters were measured at the origin of each main coronary branch and 1 cm, 3 cm and 5 cm distally. The minimum, maximum and mean diameters were determined from MSCT angiography and compared to QCA.

RESULTS

A total of 353 of 525 (67.2%) coronary artery segments were assessable by MSCT angiography. The proximal segments were more often assessable when compared to the distal segments. Stenoses were detected with a sensitivity of 82.6% and a specificity of 92.8%. According to the Bland-Altman method the mean differences between QCA and MSCT ranged from -0.55 to 1.07 mm with limits of agreement from -2.2 mm to -2.7 mm.

CONCLUSION

When compared to QCA, the ability of 3D-VRT to quantitatively assess coronary artery diameters and coronary artery stenoses is insufficient for clinical purposes.

Angiographic analysis of the angioplasty versus rotational atherectomy for the treatment of diffuse in-stent restenosis trial (ARTIST)

Patients with diffuse in-stent restenoses (ISRs) are at high risk for recurrent restenosis after percutaneous transluminal balloon angioplasty (PTCA). Percutaneous transluminal rotational ablation (PTCR) has proved effective in removing neointimal burden in ISRs. This study compares the acute and long-term results of PTCA and PTCR for the treatment of diffuse ISR in a randomized, multicenter investigation. The primary end point was the comparison of the minimum luminal diameter (MLD) between both groups at 6-month follow-up. Patients with symptomatic, diffuse, or high-grade ISRs were included; 146 patients were randomized to PTCA and 152 patients to PTCR. Diameter stenosis was reduced from 80 +/- 12% to 29 +/- 10% and from 80 +/- 11% to 28 +/- 12%, respectively, and MLD increased from 0.55 +/- 0.3 to 1.9 +/- 0.3 mm in the PTCA group and from 0.54 +/- 0.3 mm to 1.9 +/- 0.4 mm in the PTCR group. Spasm in the treated vessel and an intermittent slow flow phenomenon occurred more often after rotational ablation (17.7% vs 8.6%, p = 0.001; 5.3% vs 0%, p = 0.007). Minimum stenosis diameter at 6-month follow-up was smaller in the PTCR group than in the PTCA group (1.0 +/- 0.6 vs 1.2 +/- 0.6 mm, p = 0.008) and the restenosis rate was higher (64.9% vs 51.2%, p = 0.027). Procedural factors did not influence long-term outcome. In the PTCR group, the restenosis rate increased with decreasing vessel size, whereas this was not seen in the PTCA group. The lesion length and the baseline diameter stenosis were found to be predictive of restenosis with both treatment strategies; however, a residual diameter stenosis of <30% predicted absence of a restenosis only in the PTCR group. Thus, PTCA and PTCR of diffuse ISRs yield comparable acute angiographic results. The recurrence of a restenosis is higher after PTCR than after PTCA.

Rotational atherectomy does not reduce recurrent in-stent restenosis: results of the angioplasty versus rotational atherectomy for treatment of diffuse in-stent restenosis trial (ARTIST)

BACKGROUND

Aim of this trial was to compare rotational atherectomy followed by balloon angioplasty (rotablation [ROTA] group) with balloon angioplasty (percutaneous transluminal coronary angioplasty [PTCA] group) alone in patients with diffuse in-stent restenosis.

METHODS AND RESULTS

The ARTIST study is a multicenter, randomized, prospective European trial with 298 patients with in-stent restenosis>70% (mean lesion length, 14 +/- 8 mm) in stents, implanted in coronary arteries for >/= 3 months. In the PTCA group, angioplasty was performed at the discretion of the local investigator, and rotablation was performed by using a stepped-burr approach followed by adjunctive PTCA with low (</= 6 atm) inflation pressure. Intravascular ultrasound during the intervention and at follow-up was used in a substudy in 86 patients (45 PTCA, 41 ROTA). Angiography demonstrated no difference regarding the short-term outcome, with equivalent procedural success rates defined as remaining stenosis <30% (89% PTCA, 88% ROTA). However, the results showed that, in the long term, PTCA was a significantly better strategy than ROTA. Mean net gain in minimal lumen diameter was 0.67 mm and 0.45 mm for PTCA and ROTA, respectively (P=0.0019). Mean gain in diameter stenosis was 25% and 17% (P=0.002), resulting in restenosis (>/= 50%) rates of 51% (PTCA) and 65% (ROTA) (P=0.039). By intravascular ultrasound, the major difference was the missing stent over-expansion during PTCA after ROTA. Six-month event-free survival was significantly higher after PTCA (91.3%) compared with ROTA (79.6%, P=0.0052).

CONCLUSIONS

In terms of the primary objective of the study, PTCA produced a significantly better long-term outcome than ROTA followed by adjunctive low-pressure PTCA.

Calibration with currently available low-radiopacity catheters for scaling in digital quantitative coronary angiography

RATIONALE AND OBJECTIVES

In quantitative coronary angiography, the absolute diameters of coronary artery lumina are obtained by using a catheter as a scaling device.

METHODS

We examined the effect of x-ray opacity on the accuracy of calibration methods that use such catheters by varying the concentration of contrast medium in the catheters in phantom experiments with a digital cine imaging system.

RESULTS

With contrast-filled, currently available catheters, the average increase in the measured calibration factor from the gold standard (as determined by using a measuring scale) was 1.0% and 0.4% in the 13-cm and 17-cm image-intensifier modes, respectively, compared with -9.9% and -12.4% for catheters without contrast medium. The corresponding figures for catheters of the previous generation that lacked contrast medium were 1.0% and 0.4%, respectively. The image contrast of previous-generation catheters filled with saline was closer to that of current-generation catheters filled with contrast medium than that of current-generation catheters filled with saline.

CONCLUSIONS

When used for quantitative coronary angiography by digital angiography, currently available low-radiopacity catheters give more accurate data when filled with contrast medium.

Angiographic analysis of immediate and long-term results of PTCR vs. PTCA in complex lesions (COBRA study)

We conducted a prospective, randomized trial to compare immediate and long-term effects of percutaneous transluminal coronary angioplasty (PTCA) and high-frequency rotational atherectomy (PTCR) in patients with angiographically predefined complex coronary artery lesions (AHA type B2 and C). The relation of lesion characteristics to procedural results is reported in this angiographic analysis. Patients were randomly assigned to balloon angioplasty (n = 250 patients) or rotational atherectomy (n = 252 patients). Quantitative coronary angiography could be performed in 447 patients to evaluate immediate results and in 293 patients with a 6-month angiographic follow-up. Procedural success was comparable in the PTCR and in the PTCA group (80% vs. 76%, P = 0.260). The need for stent implantation due to a residual stenosis >50% or a bail-out situation was significantly higher in the PTCA group (9.7% vs. 2.0%, P = 0.001). In both treatment groups, diameter stenosis was effectively reduced and MLD increased. The acute gain did not differ between the two groups. At 6-month control, the restenosis rate was comparable in the PTCR and in the PTCA group (37% vs. 35%, P = 0.658), whereas diameter stenosis was significantly more severe in the PTCR group than in the PTCA group (52% vs. 46%, P = 0.039) and, correspondingly, the MLD was significantly smaller in the PTCR group (1.29 mm vs. 1.44 mm, P = 0.031). Late loss was about the same in both groups, however, net gain and net gain index were significantly higher in the PTCA group (0.82 mm vs. 0.64 mm, P = 0.008; and 31% vs. 24%, P = 0.009). Analysis of procedural results for various lesion characteristics revealed no significant difference between treatment groups. In this randomized trial, complex coronary artery lesions were treated with comparable results for angiographic and procedural success and the restenosis rate by both, PTCA and PTCR. Late loss, however, was significantly higher and net gain significantly smaller after PTCR. Stents, although infrequently used, had a relevant impact on immediate PTCA results but not on late results. Cathet Cardiovasc Intervent 2001;53:359-367.

Validation of an accurate method for three-dimensional reconstruction and quantitative assessment of volumes, lengths and diameters of coronary vascular branches and segments from biplane angiographic projections

The goal of the study was the validation of an accurate method for three-dimensional reconstruction and quantitative assessment of volumes, lengths and diameters of coronary vascular branches and segments from biplane angiographic projections.

METHODS

The accuracy was tested in a complex phantom. In vivo, inter- and intraobserver agreement were assessed by analysis of routine angiograms. The sensitivity was evaluated using angiograms of patients having diagnostic vasoactive pharmacological intervention. Two-dimensional quantitative coronary angiography (2-D QCA) and 3-D QCA were compared concerning the accuracy of diameter evaluation.

RESULTS

3-D QCA yields accurate results (< 3% error) even based on nonorthogonal views, provided that projections parallel to the object are avoided. The inter- and intraobserver variability is < or = 5%. Significant (p < 0.01) changes of the volume (36-39%) and the diameter (19-21%) are detected following pharmacological intervention. 2-D QCA and 3-D QCA agree in short matched segments without foreshortening. 2-D QCA is rather sensitive to foreshortening and not suitable for evaluation of diameters of longer branches or total coronaries.

CONCLUSION

3-D QCA permits an accurate, reproducible and sensitive comprehensive three-dimensional geometric analysis of the coronaries and is superior to 2-D QCA with respect to extended diameter evaluation.

Validation of an accurate method for three-dimensional reconstruction and quantitative assessment of volumes, lengths and diameters of coronary vascular branches and segments from biplane angiographic projections

The goal of the study was the validation of an accurate method for three-dimensional reconstruction and quantitative assessment of volumes, lengths and diameters of coronary vascular branches and segments from biplane angiographic projections.

METHODS

The accuracy was tested in a complex phantom. In vivo, inter- and intraobserver agreement were assessed by analysis of routine angiograms. The sensitivity was evaluated using angiograms of patients having diagnostic vasoactive pharmacological intervention. Two-dimensional quantitative coronary angiography (2-D QCA) and 3-D QCA were compared concerning the accuracy of diameter evaluation.

RESULTS

3-D QCA yields accurate results (< 3% error) even based on nonorthogonal views, provided that projections parallel to the object are avoided. The inter- and intraobserver variability is < or = 5%. Significant (p < 0.01) changes of the volume (36-39%) and the diameter (19-21%) are detected following pharmacological intervention. 2-D QCA and 3-D QCA agree in short matched segments without foreshortening. 2-D QCA is rather sensitive to foreshortening and not suitable for evaluation of diameters of longer branches or total coronaries.

CONCLUSION

3-D QCA permits an accurate, reproducible and sensitive comprehensive three-dimensional geometric analysis of the coronaries and is superior to 2-D QCA with respect to extended diameter evaluation.