| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
(Circulation. 1997;96:491-499.)
© 1997 American Heart Association, Inc.
Articles |
Comparison of Coronary Luminal Quantification Obtained From Intracoronary Ultrasound and Both Geometric and Videodensitometric Quantitative Angiography Before and After Balloon Angioplasty and Directional Atherectomy
From the Angiographic Research Laboratory, Thoraxcenter, Erasmus University, Rotterdam, Netherlands, and the Division of Cardiology (Y.O., T.K.), Third Department of Internal Medicine, Aichi Medical University, Nagakute, Aichi, Japan.
Correspondence to Patrick W. Serruys, MD, PhD, FESC, FACC, Professor of Interventional Cardiology, Thoraxcenter, Erasmus University, PO Box 1738, 3000 DR Rotterdam, Netherlands.
 |
Abstract |
|---|
 Top Abstract IntroductionMethodsResultsDiscussionReferences |
|---|
Background Debate exists regarding the relationship between angiographic and intracoronary ultrasound (ICUS) measurements of minimal luminal cross-sectional area after coronary intervention. We investigated this and the factors that may influence it by using ICUS and quantitative angiography.
Methods and Results Patients who underwent successful balloon angioplasty (n=100) or directional atherectomy (n=50) were examined by using ICUS and quantitative angiography (edge-detection [ED] and videodensitometry [VID]) before and after intervention. Luminal damage postintervention was qualitatively graded into three categories based on angiographic results (smooth lumen, haziness, or dissection). Correlation of minimal luminal cross-sectional area measurements by ICUS and ED was .59 before and .47 after balloon angioplasty. Correlation between ICUS and VID was .50 before and .63 after balloon angioplasty. Postintervention, the difference between ICUS and VID was less than the difference between ICUS and ED (P<.01). Additionally, the correlation was .74 between ICUS and ED measurements and .78 between ICUS and VID measurements in the smooth lumen group, .46 and .63, respectively, in the presence of haziness, and .26 and .46, respectively, in lesions with dissection. Similar results were obtained after directional atherectomy: the agreement between ICUS and quantitative angiography deteriorated according to the degree of vessel damage, but less so with VID than ED.
Conclusions Complex morphological changes induced by intervention may contribute to discordance between the two quantitative imaging techniques. In the absence of ICUS, VID may be a complementary technique to ED in lesions with complex morphology after balloon angioplasty and directional atherectomy.
Key Words: angiography • angioplasty • imaging • coronary disease • ultrasonics
|
Introduction |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
Although QCA is the gold standard in interventional cardiology, pathology studies indicate that angiography may underestimate the extent and severity of atherosclerotic disease.1 2 While ICUS provides unique information regarding vessel wall morphology compared with angiography,3 4 5 6 7 8 precise quantitative analysis of luminal CSA by ICUS would offer a significant advantage in the guidance of coronary intervention procedures.9 10 11 A recent multicenter ICUS study in patients with coronary angioplasty indicated that postinterventional luminal dimensions obtained by ICUS but not QCA may be a significant predictor of restenosis at follow-up.12 Additionally, another multicenter study suggests that a large residual plaque burden remains on ICUS imaging, despite optimal angiographic results.13 Nakamura et al9 and Colombo et al10 also suggest that luminal measurements provided by ICUS may be helpful for optimal stent deployment. Previous studies, however, have provided conflicting evidence on the agreement between quantitative measurements derived from ICUS and those derived from QCA.3 4 7 14 15 16 17 The aim of our study was to clarify whether ICUS measurements agree with QCA measurements and to determine which factors, if any, may play a role in any discordance between the techniques. To do this, we compared MCSA obtained from ICUS and both ED and VID computer-based QCA before and after BA and DCA.
|
Methods |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
Patients
Patients who had an ICUS examination before and after single-vessel BA (n=100) or DCA (n=50) with adequate quality of ICUS and angiographic images for quantitative analysis were enrolled in this study. Preintervention, the US catheter did not cross the target lesions in 20 lesions because of proximal vessel tortuosity, the severity of the target stenosis, or transient serious arrhythmia during the ICUS examination. Additionally, the ultrasound catheter completely occluded the coronary lesion in 89 lesions. Thus, preintervention MCSA of the stenotic segment was measured in the remaining 41 lesions. Postintervention ICUS measurements were obtained in all 150 lesions in the 150 patients.
BA or DCA Procedures
All patients received full anticoagulant therapy including
intravenous aspirin and heparin before ICUS examination and
intervention. Coronary angiograms were recorded on cinefilm
after the intracoronary administration of isosorbide dinitrate
(1 to 2 mg). The size of the balloon or atherectomy device was
determined to match the vessel RD obtained from the online QCA
measurement. Luminal damage postintervention was qualitatively graded
into three categories by angiographic assessment as none (smooth
lumen), generalized haziness, or dissection. Dissection was defined
according to the dissection classification types B, C, D, E, and F of
the classification of the National Heart, Lung, and Blood
Institute.18
ED-QCA
The new version of the computer-based Coronary
Angiography Analysis System (CAAS II)19 20 was
used to perform the ED and VID quantitative analyses. In the
CAAS analysis,19 20 21 22 23 24 the entire 18x24-mm cineframe
is digitized at a resolution of 1329x1772 pixels, and the boundaries
of a selected coronary segment are detected automatically. The
absolute diameters of the stenosis (MLD and RD) are determined
by using the contrast-free guiding catheter as a scaling device. To
standardize the method of analysis before and after
intervention, all study frames selected for analysis were
end-diastolic to minimize motion artifact, and
arterial segments were measured between the same
identifiable branch points in multiple views after the administration
of isosorbide dinitrate.20 21 22 23 24 MCSA was calculated as
x(MLD1)x(MLD2)÷4 from measurements obtained from the ED
analysis in orthogonal views (MLD1 and MLD2) before and
after intervention.
VID-QCA
VID measurement is based on the relationship between the
attenuating power of the lumen filled with contrast medium and the
x-ray image intensity.25 Using this relationship, a VID
profile that was proportional to the CSA of the lumen was obtained.
Subtraction of patient structure noise was applied after computing the
linear regression line through the background pixels located on both
sides of the detected luminal contours. Consecutive densitometric
profiles of the analyzed segment were acquired in all scan
lines perpendicular to the vessel including lesion, reference, and
nondiseased areas. Conversion of the individual VID profiles to
absolute values was performed after a transformation of the VID profile
found in a CSA of a nondiseased segment, assuming a CSA at any point is
proportional to the densitometric profiles at that point. MCSA was
calculated from the average value obtained from the VID system in
multiple views. The basic principles of the technique are illustrated
in Fig 1
.
|
ICUS Image Acquisition
Following angiography, an ICUS catheter (30 MHz; 2.9F, 3.2F, or
4.3F; Cardiovascular Imaging Systems) was introduced
over a 0.014-in. guide wire and positioned distal to the lesion. Lesion
geometry was then imaged by using a slow, continuous catheter pull-back
procedure. Catheter position was documented by simultaneous
fluoroscopy superimposed on the ICUS display screen. ICUS images were
stored on super VHS tape for offline analysis.
Quantitative and Qualitative Assessment of ICUS
Luminal CSA was defined as the integrated area central to the
intimal leading-edge echo. Images with MCSA were selected from the
pull-back sequence by reviewing the position of the ICUS catheter on
the angiographic image that was recorded on the same ICUS image and
by reviewing the time log and audio recording of the procedure
to analyze the same coronary segment as the
quantitative angiogram. Total vessel CSA was defined as the area inside
the interface between the plaque-media complex and adventitia (ie, the
area inside the external elastic membrane). When the dissected lumen
communicated constantly with the true lumen, the dissected lumen was
included in the luminal area, as exemplified in Fig 2.
Echo reflectivity was categorized as either low or high (plaque
reflectivity lower or higher, respectively, than the bright adventitial
layer).26 Calcium deposits were defined as highly
echo-reflective tissue with acoustic shadowing. A lesion was considered
homogeneous if the plaque consisted of >75% of one type
of echo reflectivity. A lesion was defined as mixed if it contained
both high and low echo-reflective areas occupying >25% of the plaque
area.26 A lesion was considered predominantly calcific if
calcium occupied >180° of the vessel
circumference.26
|
Luminal damage postintervention was qualitatively graded into three categories: regular lumen, irregular lumen including a small tear not extending to the media, and dissected lumen with circumferential tear behind the plaque or tear extending to the media.5 6 27 The eccentricity ratio was calculated as the ratio between minimal and maximal wall thickness (1 indicates concentric plaque, <1 indicates increasing eccentricity).27 To determine the interobserver variability of ICUS measurements, 30 videotapes of the complete original recording were used by two independent observers to select and measure the minimal CSA. The mean signed difference and correlation of the measurements of minimal CSA were -0.12±0.79 mm2 and 0.94, respectively.
Statistical Analysis
In the absence of the known true values, Bland and
Altman28 recommend the use of the mean and SD of the
signed differences between two measurement systems as an index of
agreement between the two systems. Thus, we took the mean and SD of the
signed differences between ICUS and QCA measurements as an index of
agreement between ICUS and QCA measurements instead of linear
regression analysis. The individual measurements obtained from
ICUS and QCA were compared by using the paired Student t
test and correlation coefficient. A probability value of <.05 was
considered significant.
|
Results |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
Baseline Clinical and Angiographic Characteristics
No difference was found in gender, age, anginal symptoms, or distribution of diseased vessels between the BA and DCA groups (Table 1
). QCA measurements were obtained in 100 lesions
before and after BA and in 50 lesions before and after DCA. ED-QCA
indicated that the RD before and after intervention and MLD
postintervention were significantly larger in the DCA than the BA
patients. MCSA was measured by using ICUS in 26 lesions before BA and
15 lesions before DCA without wedge of the ICUS catheter. One hundred
lesions after BA and 50 lesions after DCA were estimated by using ICUS,
which revealed that 64 lesions in BA and 31 lesions in DCA consisted of
homogeneous plaque; all remaining lesions were classified
as mixed. Most of the homogeneous plaque was low echo
reflective. Focal calcium deposits were observed in 42 lesions in BA
and 19 lesions in DCA, while moderate-to-diffuse calcification was seen
in 32 lesions in BA and 16 lesions in DCA (P=NS). Total
vessel CSA, plaque and medial CSA, and percent plaque and medial CSA
preintervention were larger in the DCA than the BA group. Lesion
eccentricity was not significantly different between the two
groups.
|
MCSA Measured by ICUS, ED-QCA, and VID-QCA Before and After
Interventions
Table 2 shows the MCSA measured by ICUS, ED-QCA,
and VID-QCA before and after BA and DCA. MCSA in nonwedged lesions
(BA=26 lesions and DCA=15 lesions) as obtained by ICUS was
significantly larger than MCSA measured by using ED- or VID-QCA pre-BA
(both P<.01) and pre-DCA (both P<.01). Post-BA
MCSA in 100 lesions as obtained by ICUS was significantly larger than
the MCSA measured by either ED- or VID-QCA (both P<.01).
Post-DCA MCSA in 50 lesions as obtained by ICUS was significantly
larger than MCSA as measured by ED-QCA (P<.01) but not
VID-QCA.
|
Agreement Between ICUS, ED, and VID Before and After BA and
DCA
Table 3 compares the agreement between the three
measurement techniques, and Figs 3 and 4
display the postintervention agreement between measurements obtained
from ICUS and ED-QCA (Fig 3) and from ICUS and VID-QCA (Fig 4). The
correlation coefficient between the ICUS and ED measurements decreased
from .59 pre-BA to .47 post-BA and from .57 pre-DCA to .44 post-DCA.
The absolute difference between ICUS and ED was significantly greater
post-BA and post-DCA than pre-BA and pre-DCA (both P<.05).
The agreement between ICUS and ED deteriorated post-BA and DCA compared
with the pre-BA and DCA agreement. The correlation coefficient between
ICUS and VID measurements increased from .50 pre-BA to .63 post-BA and
from .50 pre-DCA to .72 post-DCA (Table 3). The difference between ICUS
and VID was not significantly different from pre-BA and DCA to post-BA
and DCA. Postintervention, the difference between ICUS and VID was
significantly less than the difference between ICUS and ED post-BA and
post-DCA (both P<.01). The discordance between ICUS and VID
was smaller than the discordance between ICUS and ED both post-BA and
post-DCA. While in both pre-BA and DCA no significant difference was
observed between ED and VID, in post-BA and DCA there was a significant
difference between the two (BA, P<.001; DCA,
P<.01).
|
|
|
Luminal Damage Postintervention as Assessed by Angiography and
ICUS
The degree of luminal damage postintervention as assessed by using
angiography and ICUS is given in Table 4. Concordance
between the two qualitative imaging techniques was found in 23 (70%)
of the 33 patients with angiographically detected dissected lesions and
23 (66%) of the 35 patients with dissection as detected by ICUS
post-BA and in 10 (83%) of the 12 patients with angiographically
detected dissected lesions and 10 (59%) of the 17 patients with
dissection as detected by ICUS post-DCA.
|
Influence of Vessel Damage Induced by BA and DCA in the Agreement
Between ICUS and QCA
The correlation coefficient of ICUS and ED quantitative
measurements was .74 in lesions with an angiographically determined
smooth lumen, .46 in lesions with angiographic haziness, and .26 in
lesions with angiographic evidence of dissection (Table 5). The correlation of ICUS and ED quantitative
measurements was .70 in lesions with a regular lumen as determined by
ICUS, .52 in lesions with an irregular lumen, and .10 in lesions with
ICUS evidence of dissection. Thus, the presence of vessel damage
induced by BA was associated with a deterioration of agreement between
ICUS and ED measurements. While agreement between ICUS and VID-QCA also
deteriorated in the presence of morphological changes induced by BA,
the difference of the measurements between ICUS and VID was
significantly less than the difference between ICUS and ED in the
presence of both angiographic (P<.05) and ICUS
(P<.05) evidence of dissection. While high agreement was
obtained between ED-QCA and VID-QCA, agreement between these two
techniques also decreased post-BA according to the increase of vessel
damage.
|
A similar pattern was seen when lesions treated by DCA were categorized
according to their morphological characteristics (Table 6). Poor agreement was obtained in lesions with
angiographic or ICUS evidence of vessel damage compared with lesions
with an angiographically smooth lumen or ICUS appearance of a regular
lumen. The absolute difference of the measurement between ICUS and VID
was significantly less than the difference between ICUS and ED in the
presence of both angiographic (P<.01) and ICUS
(P<.01) evidence of dissection.
|
Correlation Between QCA Analyses of the Same Lesion From
Multiple Views
To ensure that the better relationship between VID and ICUS was a
true phenomenon and not due to a greater variation in values obtained
from different views, we looked at the correlation and differences
between orthogonal measurements for both VID and ED before and after
intervention.29 30 31 The correlation and differences between
orthogonal measurements obtained by ED were 0.69 (0.21±0.62
mm2) preintervention and 0.49 (0.39±2.33
mm2) postintervention. The values obtained for VID were
0.69 (0.14±0.71 mm2) preintervention and 0.67
(-0.33±1.79 mm2) postintervention.
|
Discussion |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
The principle findings of our study were (1) that MCSA obtained by ICUS was significantly larger than MCSA as measured by either ED- or VID-QCA both before and after BA and DCA, (2) that the agreement between ICUS and ED deteriorated considerably after both BA and DCA, (3) that the complex morphological changes induced by BA and DCA contributed to the discordance of the agreement between ICUS and ED, and (4) that VID measurements were found to provide a better agreement with ICUS than ED measurements, particularly in lesions with complex morphological changes post-BA and DCA.
Agreement Between ICUS and ED-QCA in Previous Studies
Previous studies have provided conflicting evidence on whether
luminal measurements obtained from ICUS agree with ED-QCA measurements
in human coronary arteries. In general, studies that examined
ICUS and ED measurements in normal coronary segments report a
favorable correlation between the two quantitative imaging
modalities,3 7 while those that examined lesions
postangioplasty report a poor correlation.4 15 16 Nakamura
and colleagues17 report that dissection induced by BA
plays a role in the discordance between ICUS and ED-QCA measurements,
but there are several methodological differences between their study
and ours. First, they did not examine VID measurements. Second, they
showed only the correlation coefficient in groups with and without
dissection, and no statistical difference was found in the difference
of the individual ICUS and angiographic measurements between two
groups. Finally, they did not use a computer-based QCA system but
rather caliper measurements, which have a poor reproducibility and
result in frequent underestimation or overestimation of
stenosis severity.32 Our study is the first to
compare both ED- and VID-QCA measurements with ICUS measurements.
Factors Contributing to the Discordance of ICUS and QCA
Measurements
Agreement of luminal area measurements as obtained by using ICUS
and ED deteriorated considerably after BA and DCA. A progressive
deterioration in the relationship between the ICUS and QCA measurements
was seen in accordance with the presence of increasing vessel damage
and increasing luminal complexity postintervention. Thus, the
cross-sectional shape of the vessel lumen postintervention may be a
significant factor in the discrepancy between ICUS and ED-QCA
measurements. MLD obtained from ED-QCA depends on the angiographic
projection. Although we calculated luminal area from two orthogonal
views, the chances of obtaining the exact minimal and maximal diameters
of the lesion CSA using ED-QCA would be small, particularly in the
complex elliptical shape of the lumen postintervention (Fig 5). ICUS and VID are not projection dependent, and
both would provide a measure of the "depth" as well as the
"width" of the lumen cross section. ED, however, provides only a
measure of one diameter (the "width") of the lumen.
Consistent with this is the fact that VID-QCA provided a better
agreement and less relative underestimation in relation to ICUS
measurements than ED-QCA.
|
The underestimation by ED relative to ICUS measurements may reflect the
propensity of the contour-detection algorithm to trace the change in
the brightness profile in the contrast-weak channel between the true
and false lumens33 (Fig 2
), while ICUS measurements and
VID measurements in multiple views may include the contribution of the
false lumen. Such a phenomenon, however, would not account for the
relative underestimation by ED in the preintervention phase. Another
possibility is that the interventional cardiologist tends to select
angiographic projections that best demonstrate both the
stenosis preintervention and the residual stenosis
postintervention, ie, "worst view" angiography. Even using
multiple orthogonal views, as we did in our study, the assumed
elliptical cross section may have been based on multiple "worst
views," which although they were, per protocol, >45° apart, were
not necessarily a combination of truly "worst view" and "best
view." Such a limitation to ED-QCA has been an inherent problem in
all coronary interventional trials, and attempts to address
this by three-dimensional imaging in truly orthogonal views are
currently under evaluation.34 35
Two additional ICUS-related factors may also have contributed to the
observed discordance between ICUS and quantitative angiographic
measurements. Elliptical angulation of the ultrasound catheter within
the longitudinal axis of the vessel may have led to overestimation of
luminal dimensions by ICUS. Additionally, introduction of the
ultrasound catheter may have itself resulted in tacking back of
dissection flaps, with a resultant larger lumen during ICUS
examinations postintervention compared with the less invasive technique
of contrast angiography. Our data also suggest that quantitative
angiography may yield larger luminal measurements than ICUS in a
significant number of patients (Figs 3 and 4). This increase in the
apparent angiographic diameter may be caused by extraluminal contrast
within fissures, cracks, and dissection as seen around the true lumen.
Study Limitations
First, the coronary sites compared by ICUS and QCA may not
have been exactly identical. Although we tried to ensure that this was
the case by using simultaneous recording of
fluoroscopy and ICUS imaging as well as landmarks such as side branches
to guide us, there is no guarantee that we analyzed exactly the
same point of the coronary artery in ICUS and QCA measurements.
This is, however, a generic problem of any ICUS-QCA
study3 4 that would be very difficult to overcome, as the
presence of the ICUS catheter at the lesion site during
coronary arteriography would interfere with the QCA
measurements. Second, both ED- and VID-QCA analysis were
performed using only the CAAS II system. Thus, further studies would be
required to confirm if our findings can be generalized to other QCA
hardware or software systems.21 It is conceivable that if
an ED algorithm were inaccurate in the normal reference segment, then a
systematic underestimation or overestimation of vessel diameters could
be translated to subsequent VID measurements. Third, it is also
possible that ultrasound image analysis fails to see the true
leading intimal edge, especially if the plaque has a low fibrous
component and appears relatively hypoechoic, thus overestimating
luminal dimensions. Additionally, a poor dynamic range can also induce
technical intimal drop-out, leading to lumen overestimation.
Clinical Implications
Although ICUS provides unique information regarding the vessel
wall morphology, the clinical utility of this technique remains
unproven to date. ICUS luminal measurements, however, do provide
important additional information to that obtained by visual assessment
for optimal stent implantation.9 10 Whether ICUS provides
more accurate information than QCA, however, has not yet been
determined. Additionally, whether luminal measurements obtained from
ICUS are a superior index for the short- and long-term success of
interventional procedures awaits the results of recent multicenter
trials.12 13 36 While ICUS is not universally available
and involves additional time and expense,11 QCA is more
widely available and less time-consuming. Our data suggest that in the
absence of the known true value and assuming that ICUS gives the most
accurate estimate of luminal dimensions, QCA measurements, particularly
ED, may be compromised, especially in assessing the complex luminal
morphology following BA or DCA. Our study suggests that VID may offer a
better correlation with the true luminal dimensions, as reflected by
ICUS, than ED-QCA. VID may thus be the "poor man's" ICUS,
especially in lesions with complex morphology.
Conclusions
MCSA measurements obtained by ICUS are significantly larger than
measurements provided by either geometric or VID-QCA both before and
after intervention. Agreement between ICUS and geometric QCA
measurements deteriorate considerably after intervention. Complex
morphological changes induced by intervention may play a role in such a
discordance between the two quantitative imaging techniques. In the
absence of ICUS, VID, which is currently available in an online QCA
system, may provide a better alternative than ED-QCA in lesions with
complex morphology.
|
Selected Abbreviations and Acronyms |
|---|
|
|
Acknowledgments |
|---|
We gratefully acknowledge Professor Tetsu Yamaguchi, MD, PhD (Third Department of Internal Medicine, Ohashi Hospital, Toho University School of Medicine, Tokyo, Japan) for his helpful advice.
|
Footnotes |
|---|
Presented in part at the 43rd Annual Scientific Session of the American College of Cardiology, Atlanta, Ga, March 13-17, 1994, and previously published in abstract form (J Am Coll Cardiol. 1994;23[suppl]:70A).
Received August 5, 1996; revision received January 27, 1997; accepted February 3, 1997.
|
References |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
1. Grondin CM, Dyrda I, Pasternac A, Campeau L, Bourassa MG, Lesperance J. Discrepancies between cineangiographic and post mortem findings in patients with coronary artery disease and recent myocardial revascularization. Circulation. 1974;49:703-708.
2.
Hutchins GM, Buckley BH, Ridolfi RL, Griffith LSC,
Lohr FT, Piasio MA. Correlation of coronary arteriograms
and left ventriculograms with post mortem studies.
Circulation. 1977;56:32-34.
3.
Nissen SE, Gurley JC, Grines CL, Booth DC, McClure R,
Berk M, Fisher C, DeMaria AN. Intravascular ultrasound
assessment of lumen size and wall morphology in normal subjects and
patients with coronary artery disease.
Circulation. 1991;84:1087-1099.
4.
Tobis JM, Mallery J, Mahon D, Lehmann K, Zalesky P,
Griffith J, Gessert J, Moriuchi M, McRae M, Dwyer ML, Greep N, Henry
WL. Intravascular ultrasound imaging of human coronary
arteries in vivo: analysis of tissue characterizations with
comparison to in vitro histological specimens.
Circulation. 1991;83:913-926.
5.
Fitzgerald PJ, Ports TA, Yock PG. Contribution
of localized calcium deposits to dissection after angioplasty: an
observational study using intravascular ultrasound.
Circulation. 1992;86:64-70.
6.
Honye J, Mahon DJ, Jain A, White CJ, Ramee SR, Wallis
JB, Al-Zarka A, Tobis JM. Morphological effects of
coronary balloon angioplasty in vivo assessed by intravascular
ultrasound imaging. Circulation. 1992;85:1012-1025.
7.
St. Goar FG, Pinto FJ, Alderman EL, Fitzgerald PJ,
Stinson EB, Billingham ME, Popp RL. Detection of
coronary atherosclerosis in young adult hearts
using intravascular ultrasound. Circulation. 1992;86:756-763.
8. Mintz GS, Popma JJ, Pichard AD, Kent KM, Satler LF, Chuang YAC, Ditrano CJ, Leon MB. Patterns of calcification in coronary artery disease: a statistical analysis of intravascular ultrasound and coronary angiography in 1155 lesions. Circulation. 1994;73:423-430.
9.
Nakamura S, Colombo A, Gaglione S, Almagor Y, Goldberg
SL, Maiello L, Finci L, Tobis JM. Intracoronary
ultrasound observations during stent implantation.
Circulation. 1994;89:2026-2034.
10.
Colombo A, Hall P, Nakamura S, Almagor Y, Maiello L,
Martini G, Gaglione A, Goldberg SL, Tobis JM.
Intracoronary stenting without anticoagulation accomplished
with intravascular ultrasound guidance. Circulation. 1995;91:1676-1688.
11. Ozaki Y, Keane D, Nobuyoshi M, Hamasaki N, Popma JJ, Serruys PW. Coronary lumen at 6 month follow-up of the new radiopaque Cordis tantalum stent using quantitative angiography and intracoronary ultrasound. Am J Cardiol. 1995;76:1135-1143.[Medline] [Order article via Infotrieve]
12. The GUIDE Trial Investigators. IVUS-determined predictors of restenosis in PTCA and DCA: an interim report from the GUIDE Trial, Phase II. Circulation. 1994;90(suppl I):I-23. Abstract.
13. Mintz GS, Fitzgerald PJ, Kuntz RE, Simonton CA, Bersin RM, Yock PG, Baim DM, Leon MB, for the OARS Investigators. Lesion site and reference segment remodeling after directional coronary atherectomy: an analysis from the Optimal Atherectomy Restenosis Study (OARS). Circulation. 1995;92(suppl I):I-93. Abstract.
14. Werner GS, Sold G, Buchwald A, Kreuzer H, Wiegand V. Intravascular ultrasound imaging of human coronary arteries after percutaneous transluminal angioplasty: morphologic and quantitative assessment. Am Heart J. 1991;122:212-220.[Medline] [Order article via Infotrieve]
15. DeScheerder I, Man FDE, Herregods MC, Wilczek K, Barrios L, Raymenants E, Desmet W, Geest HDE, Piessens J. Intravascular ultrasound versus angiography for measurement of luminal diameters in normal and diseased coronary arteries. Am Heart J. 1994;127:243-251.[Medline] [Order article via Infotrieve]
16. Haase J, Ozaki Y, Di Mario C, Escaned J, de Feyter P, Roelandt JRTC, Serruys PW. Can intracoronary ultrasound correctly assess the luminal dimensions of coronary artery lesions? a comparison with quantitative angiography. Eur Heart J. 1995;16:112-119.
17. Nakamura S, Mahon DJ, Maheswaran B, Gutfinger DE, Colombo A, Tobis JM. An explanation for discrepancy between angiographic and intravascular ultrasound measurements after percutaneous transluminal coronary angioplasty. J Am Coll Cardiol. 1995;25:633-639.[Abstract]
18. Huber MS, Mooney JF, Madison J, Mooney MR. Use of a morphologic classification to predict clinical outcome after dissection from coronary angioplasty. Am J Cardiol. 1991;68:467-471.[Medline] [Order article via Infotrieve]
19. Ozaki Y, Keane D, Herrman JP, Foley D, Haase J, den Boer A, Di Mario C, Serruys PW. Coronary arteriography for quantitative analysis: an experimental and clinical comparison of cinefilm and video recordings. Am Heart J. 1995;129:471-475.[Medline] [Order article via Infotrieve]
20. Serruys PW, Foley DP, de Feyter PJ, eds. Quantitative Coronary Angiography in Clinical Practice. Dordrecht, Netherlands: Kluwer Academic Publishers; 1994.
21.
Keane D, Haase J, Slager CJ, van Swijndregt EM, Lehmann
K, Ozaki Y, Di Mario C, Kirkeedee R, Serruys PW. Comparative
validation of quantitative coronary angiographic systems:
results and implications from a multicenter study.
Circulation. 1995;91:2174-2183.
22.
Ozaki Y, Keane D, Serruys PW. Progression and
regression of coronary stenosis in the long-term
follow-up of vasospastic angina: a quantitative angiographic
study. Circulation. 1995;92:2446-2456.
23.
Ozaki Y, Keane D, Ruykrok P, van der Giessen WJ, de
Feyter PJ, Serruys PW. Six-month clinical and angiographic
outcome of the new less shortening Wallstent in native coronary
arteries. Circulation. 1996;93:2114-2120.
24. Ozaki Y, Keane D, Serruys PW. Fluctuation of spastic location in patients with vasospastic angina: a quantitative angiographic study. J Am Coll Cardiol. 1995;26:1606-1614.[Abstract]
25. Serruys PW, Reiber JHC, Wijns W, van den Brand M, Kooijman CJ, ten Katen HJ, Hugenholtz PG. Assessment of percutaneous transluminal coronary angioplasty by quantitative coronary angiography: diameter versus densitometric area measurements. Am J Cardiol. 1984;54:482-488.[Medline] [Order article via Infotrieve]
26.
de Feyter PJ, Ozaki Y, Baptista J, Escaned J, Di Mario
C, deJaegere PPT, Serruys PW, Roelandt JRTC.
Ischemia-related lesion characteristics in patients with stable
or unstable angina: a study with intracoronary angioscopy and
ultrasound. Circulation. 1995;92:1408-1413.
27. Di Mario C, Gil R, Camenzind E, Ozaki Y, van Birgelen C, Uman V, deJaegere P, de Feyter PJ, Roelandt JRTC, Serruys PW. Wall recoil and intimal hyperplasia: quantitative assessment with intracoronary ultrasound of the mechanism of restenosis after balloon angioplasty and directional atherectomy. Am J Cardiol. 1995;75:772-777.[Medline] [Order article via Infotrieve]
28. Bland JM, Altman DG. Statistical methods for assessing agreement between two methods of clinical measurement. Lancet. 1986;2:307-310.
29. Escaned J, Foley DP, Haase J, Di Mario C, Hermans WR, deFeyter PJ, Serruys PW. Quantitative angiography during coronary angioplasty with a single angiographic view: a comparison of automated edge detection and videodensitometric techniques. Am Heart J. 1993;126:1326-1333.[Medline] [Order article via Infotrieve]
30. Strauss BH, Juilliere Y, Rensing BJ, Reiber JHC, Serruys PW. Edge detection versus densitometry for assessing coronary stenting quantitatively. Am J Cardiol. 1991;67:484-490.[Medline] [Order article via Infotrieve]
31. Umans VA, Strauss BH, deFeyter PJ, Serruys PW. Edge detection versus videodensitometry for quantitative angiographic assessment of directional coronary atherectomy. Am J Cardiol. 1991;68:534-539.[Medline] [Order article via Infotrieve]
32. Kalbfleisch SJ, McGillem MJ, Pinto IMF, Kavanaugh KM, DeBoe SF, Mancini GBJ. Comparison of automated quantitative coronary angiography with caliper measurements of percent diameter stenosis. Am J Cardiol. 1990;65:1181-1184.[Medline] [Order article via Infotrieve]
33. Hermans WRM, Rensing BJ, Foley DP, Deckers JW, Rutsch W, Emanuelsson H, Danchin N, Wijns W, Chappuis F, Serruys PW. Therapeutic dissection after successful coronary angioplasty: no influence on restenosis or on clinical outcome: a study in 693 patients. J Am Coll Cardiol. 1992;20:767-780.[Abstract]
34. Wollschlager H, Lee P, Zeiher A, Solzbach U, Bonzel T, Just H. Mathematical tools for spatial computations with biplane isocentric x-ray equipment. Biomed Tech (Berlin). 1986;31:101-106.[Medline] [Order article via Infotrieve]
35. Slager CJ, Laban M, von Birgelen C, Krams R, Oomen JAF, den Boer A, Wenguang L, de Feyter PJ, Serruys PW. ANGUS: a new approach to three-dimensional reconstruction of geometry and orientation of coronary lumen and plaque by combined use of coronary angiography and IVUS. J Am Coll Cardiol. 1995;25(suppl):144A. Abstract.
36. Baim DS, Kuntz RE, Sharma SK, Fortuna R, Feldman R, Senerchia C, Defeo T, Popma JJ, Ho KKL, for the BOAT Investigators. Acute results of the randomized phase of the Balloon Versus Optimal Atherectomy Trial (BOAT). Circulation. 1995;92(suppl I):I-544. Abstract.
37. Metz JA, Fitzgerald PJ, Oshima A, Hayase M, Weissman NJ, Diver DJ, Moses J, Pepine CJ, Uren NG, Oesterle SN, Yock PG. Impact of intravascular ultrasound guidance on stenting in the CRUISE substudy. Circulation. 1996;94(suppl I):I-199. Abstract.
This article has been cited by other articles:
 |
|
 |
|
  F. Alfonso Nonocclusive coronary dissections: to stent or not to stent? J. Am. Coll. Cardiol., July 1, 2000; 36(1): 303 - 304. [Full Text] [PDF]
|
|
|
|
 |
|
 F. Alfonso Videodensitometric vs edge-detection quantitative angiography. Insights from intravascular ultrasound imaging Eur. Heart J., April 2, 2000; 21(8): 604 - 607. [PDF]
|
|
|
|
|
|
R.J.G Peters, W.E.M Kok, G Pasterkamp, C Von Birgelen, M Prins, and P.W Serruys Videodensitometric quantitative angiography after coronary balloon angioplasty, compared to edge-detection quantitative angiography and intracoronary ultrasound imaging Eur. Heart J., April 2, 2000; 21(8): 654 - 661. [Abstract] [PDF]
|
|
|
|
|
|
P. W. Serruys, I. P. Kay, C. Disco, N. V. Deshpande, P. J. de Feyter, and on behalf of the BENESTENT I BENESTENT II Pilot BE Periprocedural quantitative coronary angiography after Palmaz-Schatz stent implantation predicts the restenosis rate at six months: Results of a meta-analysis of the belgian netherlands stent study (BENESTENT) I, BENESTENT II pilot, BENESTENT II and MUSIC trials J. Am. Coll. Cardiol., October 1, 1999; 34(4): 1067 - 1074. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||