|
|
||||||||||
|
J Am Coll Cardiol, 2001; 37:1019-1025 © 2001 by the American College of Cardiology Foundation |




* Harbor-UCLA Medical Center, Torrance, California, USA
Centro Cuore Columbus, Milan, Italy
Manuscript received November 5, 1999; revised manuscript received November 10, 2000, accepted December 13, 2000.
Reprint requests and correspondence: Dr. Steven L. Goldberg, Division of Cardiology, University of Washington School of Medicine, Box 356115, 1959 NE Pacific Street, Seattle, Washington 98195-6115
stevgold{at}u.washington.edu
| Abstract |
|---|
|
|
|---|
This study was performed to investigate the causes of diffuse and aggressive intra-stent restenosis.
BACKGROUND
Although restenosis is usually considered to be a dichotomous variable, there is clinical relevance to the severity of restenosis. It is not known which variables are predictive of diffuse or aggressive intra-stent restenosis.
METHODS
A consecutive series of 456 coronary lesions with in-stent restenosis was evaluated for the type of restenosis using quantitative coronary angiography. Restenosis was defined as
50% diameter stenosis at follow-up angiography, diffuse restenosis as a follow-up lesion length
10 mm and aggressive restenosis as either an increase in lesion length from the original lesion or a restenotic narrowing tighter than the original. Clinical, anatomic and procedural characteristics were evaluated for lesions associated with these types of restenosis.
RESULTS
Diffuse restenosis was associated with a smaller reference artery diameter, longer lesion length, female gender, longer stent length and the use of coil stents. Aggressive restenosis was more common in women, with the use of Wallstents and with long stent to lesion length ratios. Aggressive restenosis occurred earlier and was more closely associated with symptoms and myocardial infarctions than nonaggressive restenotic lesions.
CONCLUSIONS
Markers for diffuse restenosis were also important markers for the presence of any restenosis. A long stent to lesion length ratio is an important marker for aggressive restenosis. When severe forms of in-stent restenosis occur, they tend to present earlier and with more symptoms, including myocardial infarction. More careful consideration of the type of in-stent restenosis may aid in identifying when alternative strategies may be useful.
| ||||||||||
| Methods |
|---|
|
|
|---|
50% diameter stenosis on the follow-up angiogram. A diffuse restenosis was defined as a follow-up lesion length
10 mm or a total occlusion. A proliferative restenosis was defined as an increase in lesion length from the time of the original intervention to the follow-up angiogram. An aggressive restenosis was defined as either a proliferative restenosis or a restenotic narrowing that was tighter than the original narrowing. A previous report from this institution identified the characteristics predictive of angiographic restenosis (4). For this analysis, characteristics were evaluated for predictors of diffuse restenosis and aggressive restenosis. The evaluated characteristics are listed in Table 2 and can be organized as baseline clinical and angiographic features as well as procedural characteristics.
|
|
Stent length was calculated as the sum of the nominal lengths of each implanted stent. Stents were characterized as being: 1) tubular (Palmaz-Schatz, Cordis/Johnson & Johnson Interventional, Warren, New Jersey; AVE GFX, Arterial Vascular Engineering, Inc., Santa Rosa, California; Multilink, Guidant/Advanced Cardiovascular Systems, Santa Clara, California; NIR, Medinol Ltd., Tel Aviv, Israel; BeStent, Medtronic Interventional, San Diego, California; Pura and Pura-Vario, Devon Medical, Hamburg, Germany); 2) coil (Gianturco-Roubin Flexstent, Cook Interventional, Bloomington, Indiana; Gianturco-Roubin 2, Cook Interventional; Wiktor, Medtronic Interventional Inc., San Diego, California; Cordis stent, Cordis/Johnson & Johnson, Warren, New Jersey); or 3) mesh (Wallstent or Magic Wallstent, Schneider Europe, Lausanne, Switzerland).
Statistical analysis. Categorical variables were assessed by chi-square analysis. Normally distributed continuous variables are reported as mean ± standard deviation and compared by analysis of variance followed by the Scheffe F test. Variables without normal distributions are presented as median values and were evaluated with the Mann-Whitney U or the Mantel-Cox log-rank test. A p value <0.05 was considered statistically significant.
The association between the restenosis outcomes (diffuse restenosis or aggressive restenosis) and the potential predictors was assessed via logistic regression methods. To allow for correlation of type of restenosis within the same patient, the random effect of patient on lesions was controlled for in the logistic models using the generalized estimating equation methods of Zeger and Liang (6).
Factors that were biologically relevant and statistically significant in a univariate analysis were included in the multivariate analysis. Backward elimination was used to eliminate potential predictors. The univariate and multivariate odds ratios (ORs) and their corresponding 95% confidence intervals (CIs) are given. The unit measurements used to calculate the ORs were 1 mm for MLD and reference lumen diameter, 10 mm for lesion length and stent length, 1 mm2 for intra-stent cross-sectional area and 10 years for age. Outcomes specific to lesions, such as the length of restenosis, were evaluated on a per-lesion basis. Outcomes relating to patients, such as death or myocardial infarction (MI), were evaluated on a per-patient basis.
| Results |
|---|
|
|
|---|
50%, providing an overall angiographic restenosis rate of 25%. A previous report from this laboratory revealed the following characteristics as predictive of intra-stent restenosis: 1) a smaller final intra-stent cross-sectional area; 2) a longer total stent length; 3) a smaller reference artery lumen diameter; 4) the presence of a dissection; 5) older age and 6) prior history of coronary artery bypass graft surgery (4). Diffuse in-stent restenosis. Diffuse restenosis was seen in 286 of the 456 restenotic narrowings (63%), with 84 of these presenting at follow-up as total occlusions (18% of all in-stent restenotic narrowings or 4.6% of all stented lesions). Univariate and multivariate predictors of diffuse restenosis are presented in Tables 2 and 3 respectively. Diffuse restenosis was associated with a smaller reference artery diameter, smaller baseline MLD, longer lesion length, female gender and a smaller final minimal lumen diameter. The stent type used, in particular coil design or Wallstent, was also associated with diffuse restenosis. By multivariate logistic regression, a longer baseline lesion length, a smaller final result achieved and the use of coil stents remained independent predictors of diffuse in-stent restenosis.
|
Technical features associated with achieving larger intra-stent luminal results were not associated with diffuse restenosis. Final balloon size used to expand the stent, balloon-to-artery ratio or inflation pressures used were not significantly different between diffuse and focal in-stent restenosis. Diffuse restenosis was associated with smaller final luminal dimensions compared with focally restenotic lesions. There were 358 patients with more than one lesion treated. Similar to other centers findings (7), we found that when restenosis occurred in one of a patients lesions, other lesions within that individual were more likely to have restenosis (54% vs. 18%) when the first lesion did not demonstrate restenosis (p < 0.001, OR 5.3). In the 118 instances when two or more lesions were restenotic in the same patient, there was a strong correlation with the type of restenosis (diffuse or focal) between the two lesions, with an OR of 3.50 (CI 1.45 to 8.45, p = 0.005) that if one lesion was diffuse the other was more likely to be diffuse.
Predictors of aggressive restenosis. An aggressive restenosis process was defined as either: 1) an increase in lesion length; or 2) a decrease in MLD at the time of in-stent restenosis compared with baseline. Lesions with aggressive restenosis had greater late loss (2.2 ± 0.7 vs. 1.9 ± 0.6, p < 0.0001), despite lesser acute gains during the intervention (2.1 ± 0.7 vs. 2.4 ± 0.6, p < 0.0001). Predictors of an aggressive restenosis process are shown in Tables 2 and 4. Aggressive in-stent restenosis was more common in women, in shorter lesions and with larger baseline MLDs. The use of Wallstents, and long stent to lesion length ratios, were associated with aggressive restenosis as were less optimal results identified by intravascular ultrasound. By multivariate logistic regression analysis controlling for person effect, we found that female gender, a large baseline MLD, a shorter baseline lesion length and a greater stent to lesion length ratio were predictors of aggressive restenosis.
|
|
|
| Discussion |
|---|
|
|
|---|
Diffuse and aggressive restenosis predictors. In addition to the baseline lesion length, the presentation of a diffuse restenosis was predicted by a smaller final luminal result achieved inside the stent and by the use of specific coil stents.
An aggressive restenosis, defined as the development of a longer or tighter lesion at follow-up compared with baseline, was predicted using multivariate logistic regression analysis by the ratio of the stent length to the baseline lesion length. The strong relationships between a large MLD at baseline, or a short baseline lesion length, and the development of an aggressive restenosis are artifacts of the definition of aggressive restenosis. A very small lumen diameter to start with (such as a baseline total occlusion) has very little room to become tighter, whereas a large baseline lumen is more likely to be at least slightly smaller when restenosis occurs. Similarly, a short lesion length was more likely to be longer on follow-up. Women were more likely to develop an aggressive restenosis, suggesting important person-related effects.
Controllable characteristics. Some have proposed that aggressive stent implantation techniques using oversized balloons and/or high-pressure inflations may contribute to a more aggressive restenotic process (1012). In this study there was little evidence that inflation pressures or balloon sizes used to expand the stents were related to worsened restenosis. Instead, the final result obtained, particularly as identified by intravascular ultrasound, was consistently related to the restenotic process, with larger final results associated with more favorable angiographic outcomes (Fig. 3) (4).
|
Stent selection. The prevalent finding that coil stents and Wallstents had higher associations with the presence and severity of restenosis suggests there may be important relationships between certain stent types and the restenotic process. In randomized studies, a higher angiographic restenosis rate was seen with the Gianturco-Roubin II stent compared with the Palmaz-Schatz stent (13). In this study Gianturco-Roubin II coil stents were strongly associated with diffuse restenosis. These studies together suggest there is an important interaction of stent design with the restenotic process.
Previous analysis has supported a relationship between the amount of metal implanted and the development of in-stent restenosis (4). The current analysis demonstrates a strong association with the amount of metal implanted and the development of a proliferative restenosis. A significant predictor of an increase in lesion length was the stent to lesion length ratio. This ratio was not predictive of any angiographic restenosis, however. It appears that the interaction of the metal with the arterial wall promotes intimal proliferation in a subset of individuals. When this predilection is not present, additional stent length may help in achieving an optimal luminal result along the length of the artery. However, when this predilection is present, the resultant restenosis tends to extend further along the length of the stented segment.
Restenosis as a nondichotomous variable. The current study showed that the most important characteristics predicting the presence or absence of restenosis were also important in predicting the severity of restenosis (Fig. 3). This suggests that restenosis is a graded, not merely a dichotomous, process. Large arteries are more commonly free of restenosis after stenting, whereas small arteries develop not only restenosis but diffuse and/or aggressive restenosis, with intermediate arteries presenting with less severe forms.
The tradition of considering the restenotic process as strictly dichotomous may have directed attention away from clinically relevant differences. For example, two different stent types may have similar rates of restenosis, but if one presents in a simple, easily treated fashion and the other presents in a complex, more refractory manner, clinical differences may be significant. None of the randomized trials of stenting to date have reported on the characteristics of restenosis.
Study limitations. This analysis is retrospective and uncontrolled. There were wide variations in lesion characteristics, stent types and strategies employed. Multiple statistical analyses were performed, making it possible that some of the associations were due to type I errors. Consistency of relationships across different analyses should be considered more important than any single finding alone.
The end points of this analysis depended upon the quantitative coronary angiographic determinations of the measured lesion length; however, this measurement carries greater subjectivity than other quantitative angiographic determinants. In-stent restenosis often presents as closely grouped sequential narrowings as opposed to single, specific lesions. Precise definitions of single versus multiple lesions within an artery were prospectively created and adhered to when the quantitative angiographic measurements were performed to minimize subjectivity.
Follow-up after in-stent restenosis was not available for this study. However, more MIs and earlier presentations occurred as the restenosis severity increased, supporting an important clinical significance of the degree of restenosis severity. Other investigators have found correlations with the severity of restenosis presented and an increased likelihood of further events (14,15).
Conclusions. Markers for diffuse restenosis were also important markers for the presence of any restenosis and included the baseline lesion length, the length of stent implanted, the final result achieved inside the stented segment and the stent type used. An important marker for a proliferative restenosis was the relative length of stent implanted to the original lesion length. When aggressive forms of in-stent restenosis occur, they tend to present earlier and are more likely to present as a MI. More careful consideration of the type of in-stent restenosis may aid in identifying when alternative strategies may be useful.
| Acknowledgments |
|---|
| References |
|---|
|
|
|---|
This article has been cited by other articles:
![]() |
D Perera, P Postema, R Rashid, S Patel, L Blows, M Marber, and S Redwood Does a well developed collateral circulation predispose to restenosis after percutaneous coronary intervention? An intravascular ultrasound study Heart, June 1, 2006; 92(6): 763 - 767. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. A. Batyraliev, I. V. Pershukov, Z. A. Niyazova-Karben, A. Karaus, O. Calenici, N. Guler, B. Eryonucu, A. Temamogullari, S. Ozgul, F. Akgul, et al. Current Role of Laser Angioplasty of Restenotic Coronary Stents Angiology, January 1, 2006; 57(1): 21 - 32. [Abstract] [PDF] |
||||
![]() |
U Dietz, N Holz, C Dauer, and H Lambertz Shortening the stent length reduces restenosis with bare metal stents: matched pair comparison of short stenting and conventional stenting Heart, January 1, 2006; 92(1): 80 - 84. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. Sahara, H. Kirigaya, Y. Oikawa, J. Yajima, K. Ogasawara, H. Satoh, K. Nagashima, H. Hara, Y. Nakatsu, and T. Aizawa Arterial remodeling patterns before intervention predict diffuse in-stent restenosis: An intravascular ultrasound study J. Am. Coll. Cardiol., November 19, 2003; 42(10): 1731 - 1738. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. V. Dee and H. Samady Evolving Strategies for the Prevention and Treatment of Coronary Restenosis Seminars in Cardiothoracic and Vascular Anesthesia, September 1, 2003; 7(3): 281 - 293. [Abstract] [PDF] |
||||
![]() |
P. V. Oemrawsingh, G. S. Mintz, M. J. Schalij, A. H. Zwinderman, J. W. Jukema, and E. E.v.d. Wall Intravascular Ultrasound Guidance Improves Angiographic and Clinical Outcome of Stent Implantation for Long Coronary Artery Stenoses: Final Results of a Randomized Comparison With Angiographic Guidance (TULIP Study) Circulation, January 7, 2003; 107(1): 62 - 67. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. Farb, D. K. Weber, F. D. Kolodgie, A. P. Burke, and R. Virmani Morphological Predictors of Restenosis After Coronary Stenting in Humans Circulation, June 25, 2002; 105(25): 2974 - 2980. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. Kimura, K. Abe, S. Shizuta, K. Odashiro, Y. Yoshida, K. Sakai, K. Kaitani, K. Inoue, Y. Nakagawa, H. Yokoi, et al. Long-Term Clinical and Angiographic Follow-Up After Coronary Stent Placement in Native Coronary Arteries Circulation, June 25, 2002; 105(25): 2986 - 2991. [Abstract] [Full Text] [PDF] |
||||
![]() |
H. C. Lowe, S. N. Oesterle, and L. M. Khachigian Coronary in-stent restenosis: Current status and future strategies J. Am. Coll. Cardiol., January 16, 2002; 39(2): 183 - 193. [Abstract] [Full Text] [PDF] |
||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | SUBSCRIPTIONS | CURRENT ISSUE | PAST ISSUES | CARDIOSOURCE | SEARCH | HELP | FEEDBACK |