Clinical, physiologic, anatomic and procedural factors predictive of restenosis after percutaneous transluminal coronary angioplasty

Angiographic predictors of recurrence of restenosis after Wiktor stent implantation in native coronary arteries

Intracoronary stenting has been proposed as an adjunct to balloon angioplasty to improve the immediate and long-term results. However, late luminal narrowing has been reported following the implantation of a variety of stents. One of the studies conducted with the Wiktor stent is a prospective registry designed to evaluate the feasibility, safety and efficacy of elective stent implantation in patients with documented restenosis of a native coronary artery. To identify angiographic variables predicting recurrence of restenosis, the angiograms of the first 91 patients with successful stent implantation and without clinical evidence of (sub)acute thrombotic stent occlusion were analyzed with the Computer Assisted Angiographic Analysis System using automated edge detection. The incidence of restenosis was 44% by patient and 45% by stent according to the 0.72 mm criterion, and 30% by patient and 29% by stent according to the 50% diameter stenosis criterion. The risk for restenosis for several angiographic variables was determined using an univariate analysis and is expressed as odds ratio with corresponding confidence interval. The only statistically significant predictor of restenosis was the relative gain when it exceeded 0.48 using the 0.72 mm criterion (odds ratio 2.7, 95% confidence interval 1.1-6.4). Furthermore, the relation between the relative gain (increase in minimal luminal diameter normalized to vessel size) as angiographic index of vessel wall injury and relative loss (decrease in minimal luminal diameter normalized to vessel size) as index of neointimal thickening was analyzed using a linear regression analysis. When using the categorical approach to address restenosis, there is an increased risk for recurrent restenosis when the relative gain exceeds 0.48. The continuous approach underscores this concept by indicating a weak but positive relation between the relative gain and relative loss.

Long-term outcome following successful reopening of abrupt closure after coronary angioplasty

Abrupt closure after coronary angioplasty is often successfully treated by repeat dilation. Long-term follow-up, including 6-month repeat catheterization and 12-month clinical evaluation, was obtained in 1,056 patients treated with acute (n = 335) or elective (n = 721) coronary angioplasty to evaluate the long-term impact of successful reopening of abrupt closure. Abrupt closure occurred in 13.5% of patients and was successfully reopened in 58%. Adverse outcomes including restenosis, death, bypass surgery, myocardial infarction and repeat angioplasty were compared between patients with successfully treated abrupt closure and those with successful procedures (residual diameter stenosis < or = 50%) without abrupt closure. For patients with acute angioplasty, the restenosis rates (> 50% diameter stenosis at follow-up) were 64% for those with successfully treated abrupt closure versus 36% for those with successful procedures without abrupt closure (p < 0.01). In addition, subsequent myocardial infarction (12 vs 3%; p = 0.01) and repeat angioplasty (21 vs 10%; p = 0.03) were more frequent in the group with abrupt closure. For patients with elective angioplasty, restenosis was 43% in those with successfully treated abrupt closure versus 45% in those without abrupt closure (p = NS). Subsequent death and myocardial infarction were more frequent in patients with abrupt closure (death: 12 vs 3% [p < 0.01]; myocardial infarction: 13 vs 3% [p < 0.01]). Long-term adverse events are increased in patients with successfully treated abrupt closure compared to those with successful procedures without abrupt closure.

Treatment of long coronary artery narrowings with long angioplasty balloon catheters

Balloon angioplasty of long coronary artery narrowings has been associated with a lower rate of acute success, and a higher rate of acute complications and restenosis than that observed for short narrowings. Angioplasty catheters with longer length balloons (30 and 40 mm) are now available, and the objective of this study was to determine the acute and long-term success for patients with long coronary artery narrowings treated with these longer balloons. All patients with long narrowings (> or = 10 mm) treated with long balloons at 1 institution over a 1-year period were identified (93 narrowings in 89 patients), and acute and long-term outcomes were carefully documented. Procedural success (residual stenosis < or = 50%) was 97%. Abrupt closure occurred in 6% and major dissection in 11% of narrowings. Clinical success (procedural success without in-hospital death, bypass surgery or myocardial infarction) was achieved in 90% of patients. Repeat catheterization was performed in 61 patients (76% of those eligible), and restenosis was found in 50 to 55%, depending on the definition used. The treatment of long coronary artery narrowings using angioplasty catheters with longer balloons leads to high rates of acute success. However, there is a high rate of restenosis. New interventional devices for long lesions should be compared with long balloons in a randomized controlled trial.

Five- to ten-year outcome after multivessel percutaneous transluminal coronary angioplasty

The early and late outcome of patients who underwent multivessel percutaneous transluminal coronary angioplasty (PTCA) in a 1-stage procedure are described, and the predictors for clinical event and new revascularization procedure are identified. Of 1,937 patients treated by PTCA between 1981 and 1986, 203 (10.4%) had multivessel PTCA in a 1-step procedure. A follow-up extending to 71 +/- 23 months was obtained in 195 patients (96%). Primary success was achieved in 91% of 494 attempted sites, and complete revascularization in 65% of 203 patients. There were no in-hospital deaths. Acute complications occurred in 13 patients (6.4%), including non-Q-wave (n = 8) and Q-wave (n = 5) infarction, and urgent coronary artery bypass surgery (n = 3). Before PTCA, 126 patients (62%) were in class III or IV of the Canadian Cardiovascular Society classification; at follow-up, 84% were angina-free or in class I. Death occurred in 14 patients and nonfatal myocardial infarction in 18. Angiographic restenosis was diagnosed in 37.2% of dilated lesions in 96 patients (60% of 159 restudied). A repeat revascularization procedure for restenosis or progression of disease, or both, was needed in 92 symptomatic patients (47%). The survival rate at 7 years without the need for surgery or PTCA was 53%, and cardiac survival without myocardial infarction was 85.5%. The only independent predictor of cardiac death was ejection fraction (p < 0.001). The rate of restenosis per patient was primarily determined by the number of segments dilated, whereas progression of disease was related to the number of nonsignificant coronary artery stenoses (< 50%) at baseline (p < 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)

Definition and measurement of restenosis after successful coronary angioplasty: implications for clinical trials

Angiographic restenosis represents the most established measure of long-term outcome in most prospective clinical trials of coronary angioplasty (PTCA). The accuracy of assessing this endpoint is of utmost importance. The purpose of this article is to propose guidelines for the use of coronary angiography in this setting. First, the cineangiograms must be of high technical quality and performed in a high proportion of consecutive patients in follow-up under controlled study conditions that are reproducible. Second, computer-assisted quantitative coronary angiographic analysis is essential to minimize interobserver and intraobserver variability in stenosis measurement between successive studies. The following recommendations are presented for quantitative coronary angiographic analysis. Because biplane orthogonal views cannot always be performed both at baseline and at follow-up, stenosis measurement in the single-plane, most severe view often constitutes the most consistent and practical approach. The edge-detection method is still much more reproducible and accurate than densitometry and should be the preferred method of analysis. Measurement of reference diameter by the interpolated method is more objective than measurement by the user-defined approach and should be used whenever possible. Finally, measurements of absolute minimum diameter and percent diameter stenosis are both important in the assessment of outcome in clinical trials. Absolute minimum diameters are independent of variations in reference diameter, and the extent of reduction in minimum diameter between the immediate postangioplasty and follow-up angiograms, when expressed in dichotomous or continuous fashion, accurately defines the extent of vessel wall hyperplasia as an endpoint. On the other hand, vessel size corresponds in general to the size of myocardium subserved, and absolute changes do not take into account this physiologic fact. Therefore defining restenosis in terms of significant reduction in percent diameter stenosis is also a useful approach because of its clinical relevance. Thus clinical restenosis requires that a successfully dilated segment (< 50% diameter stenosis) show a > or = 50% diameter stenosis at follow-up angiography with, in addition, a meaningful degree of change, that is, exceeding 2 SDs of observer variability in quantitative measurements which, in our experience, translates into > or = 15% difference between early postangioplasty and follow-up angiography measurements.

Rotational coronary atherectomy after unsuccessful coronary balloon angioplasty

The clinical and angiographic outcome of patients undergoing rotational coronary atherectomy after unsuccessful balloon angioplasty was evaluated using quantitative angiographic methods to provide insight into this procedure's mechanism of benefit. During the study period, 41 patients (50 lesions) were referred for rotational atherectomy after standard balloon angioplasty was unsuccessful. After rotational atherectomy, percent diameter stenosis was reduced from 72 +/- 14% to 41 +/- 16% (p < 0.001); adjunct balloon angioplasty was performed in 44 lesions (88%), resulting in a 25 +/- 17% final diameter stenosis (p < 0.001). The acute gain in minimal lumen diameter was 1.20 +/- 0.59 mm. In lesions needing adjunct balloon dilatation, lesion stretch was 73 +/- 27%, and elastic recoil was 22 +/- 18%, with no variation by etiology of the initial balloon failure. Overall angiographic success (< 50% residual diameter stenosis) was obtained in 49 lesions (98%). Procedural success, defined as < 50% residual diameter stenosis and the absence of major in-hospital complications (death, Q-wave myocardial infarction or emergency bypass surgery), was obtained in 37 of 41 procedures (90%); complications developed in 3 patients (7%), including 2 who needed emergency bypass surgery after development of delayed abrupt closure. It is concluded that rotational coronary atherectomy may be used in selected patients when standard balloon angioplasty is unsuccessful. Its mechanism of benefit appears related, at least in part, to changes in plaque compliance resulting from partial atheroma ablation.

Intracoronary ultrasound predictors of adverse outcomes after coronary artery interventions

OBJECTIVES

The purpose of this study was to determine the association between qualitative and quantitative lesion characteristics as assessed by intracoronary ultrasound imaging and adverse outcomes after coronary artery interventions.

BACKGROUND

Restenosis and other adverse outcomes after coronary artery interventions may be difficult to predict from clinical or angiographic data. Intracoronary ultrasound imaging provides additional data that could prove useful.

METHODS

Immediately after successful coronary artery interventions (angiographic residual stenosis < or = 50%), 69 patients underwent intracoronary ultrasound imaging. Images were assessed qualitatively for plaque composition and topography and for dissection. Quantitative data included measurement of minimal lumen diameter, lumen area, plaque area and percent area stenosis at the treatment and adjacent reference sites. Adverse outcome was defined as death, coronary bypass surgery, myocardial infarction or angiographic restenosis.

RESULTS

Of the 69 patients, 1 died, 3 had bypass surgery and 1 had a myocardial infarction before planned 6-month repeat catheterization. Two patients were lost to follow-up study. Of the remaining 62 patients, 56 (90%) agreed to follow-up catheterization and 25 (45%) of the 56 had restenosis. Thus, 30 patients had an adverse outcome and 37 had no adverse event. The incidence of dissection detected by ultrasound imaging after an intervention was significantly greater in patients with than in those without a subsequent adverse event (63% vs. 35%, p < 0.05). The severity of dissection also appeared to be related to outcome (p < 0.05). Other qualitative and quantitative variables were not significantly different between the two patient groups.

CONCLUSIONS

Dissection, as assessed by intracoronary ultrasound imaging after a coronary artery intervention, can identify patients at increased risk of subsequent adverse events. Additional studies are warranted to explore whether such imaging may allow modification of interventional procedures to improve outcome.

Therapeutic dissection after successful coronary balloon angioplasty: no influence on restenosis or on clinical outcome in 693 patients. The MERCATOR Study Group (Multicenter European Research Trial with Cilazapril after Angioplasty to prevent Transluminal Coronary Obstruction and Restenosis)

OBJECTIVES

The objective of this study was to examine the relation between an angiographically visible coronary dissection immediately after successful coronary balloon angioplasty and a subsequent restenosis and long-term clinical outcome.

BACKGROUND

The study population comprised all 693 patients who participated in the MERCATOR trial (randomized, double-blind, placebo-controlled restenosis prevention trial of cilazapril, 5 mg two times a day).

METHODS

Cineangiographic films were processed and analyzed at a central angiographic core laboratory, without knowledge of clinical data, with use of an automated interpolated edge detection technique. Dissection was judged according to the National Heart, Lung, and Blood Institute classification. Angiographic follow-up was obtained in 94% of patients with 778 lesions. Two approaches were used to assess the restenosis phenomenon: 1) categoric, using the traditional cutoff criterion of greater than 50% diameter stenosis at follow-up, and 2) continuous, defined as absolute change in minimal lumen diameter (mm) between the postcoronary angioplasty and follow-up, adjusted for the vessel size (relative loss). Clinical outcome was ranked according to the most serious adverse clinical event per patient during the 6-month follow-up period, ranging from death, nonfatal myocardial infarction, coronary revascularization and recurrent angina requiring medical therapy to none of these.

RESULTS

Dissection was present in 247 (32%) of the 778 dilated lesions. The restenosis rate was 29% in lesions with and 30% in lesions without dissection (relative risk 0.97; 95% confidence interval 0.77 to 1.23). The relative loss in both groups was 0.10 (mean difference 0; 95% confidence interval -0.03 to 0.03). Clinical outcome ranged from death in 4 patients (0.9%) without dissection and 1 patient (0.4%) with dissection; nonfatal myocardial infarction in 4 (0.9%) without and 8 (3.2%) with dissection; coronary revascularization in 73 (16.6%) without and 32 (12.7%) with dissection; recurrent angina requiring medical therapy in 88 (20%) without and 47 (18.7%) with dissection to no serious adverse event in 272 (61.7%) without and 114 (65.1%) with dissection.

CONCLUSIONS

These data indicate that a successfully dilated coronary lesion with an angiographically visible dissection is no more likely to develop restenosis, and is not associated with a worse clinical outcome, at 6-month follow-up than is a dilated lesion without visible dissection on the post-balloon angioplasty angiogram.

Acute and long-term outcome of narrowed saphenous venous grafts treated by endoluminal stenting and directional atherectomy

Angioplasty of the narrowed saphenous vein bypass grafts remains a difficult challenge. Over a 37-month period at this institution, 119 of 176 interventions (68%) on saphenous vein grafts (average age 8.3 years from bypass surgery to graft intervention) were performed using either directional coronary atherectomy (n = 35) or Palmaz-Schatz intracoronary stents (n = 84), representing 37% of all stents and 15% of all atherectomies during the study period, respectively. Of the 57 saphenous vein graft lesions treated with conventional balloon angioplasty during this period, 49 (86%) had 1 or more contraindications to stenting or directional atherectomy (thrombus, total occlusion, reference vessel less than 3 mm in diameter). The acute success rate was 99% for stents (1 failure to dilate) and 94% for directional atherectomy (2 failures to cross the lesion with the atherectomy device). Lumen diameter increased from 0.9 to 3.6 mm (reference vessel 3.6) for stents, and from 0.9 to 3.5 mm (reference 3.8) for atherectomy (for all comparisons, p = not significant), with no major complications (abrupt or subabrupt closure, emergent coronary bypass surgery, death, or Q-wave myocardial infarctions). During the same time period 50 of 57 vein grafts (88%) rejected for stenting or atherectomy were dilated successfully by conventional balloon angioplasty, with 3 patients (5%) requiring emergent coronary bypass surgery. Angiographic follow-up was available for 50 of 64 eligible patients (78%).(ABSTRACT TRUNCATED AT 250 WORDS)