Efficacy of Repeat Percutaneous Transluminal Angioplasty for Coronary Restenosis

Coronary

DAVID 0. WILLIAMS, MD, ANDREAS R. GRUENTZIG, MD, KENNETH M. KENT, MD,

KATHERINE M. DETRE, MD, DrPH, SHERYL F. KELSEY, PhD, and TERESA TO, MS

The short- and long-term outcome of patients within the NHLBI PTCA Registry who underwent repeat PTCA for coronary restenosis were analyzed. Of 1,880 patients in whom an initial PTCA was suc- cessful, 203 had a repeat PTCA attempted after restenosis developed. Repeat PTCA was usually performed within 8 months of the first procedure. The success rate of repeat PTCA was 85.2 %. As a direct result of repeat PTCA, 1.5% of patients had an Ml and 2% required emergency CABG. No pa- tient died as a result of the attempted second pro- cedure. One to 3 years of follow-up information was available in 94 % of eligible patients. Most patients

(75.9 % ) did not have a subsequent (third) PTCA, CABG or an MI. The late mortality rate was 0.8%. Angiographic follow-up information was available in 82 patients. Sustained enhancement of the di- ameter of the redilated lesion was observed in 86 %. Thus, repeat PTCA has a high success and a low complication rate. Most patients did not have sub- sequent restenosis and are free of angina. Hence, repeat PTCA should be recommended for patients who have restenosis and should be considered as an integral component of PTCA therapy.

(Am J Cardiol 1984;53:32C-35C)

In 1979, NHLBI established a voluntary registry of patients who had undergone PTCA. The results of the acute outcome of PTCA have been reported by this Registry.’ Investigators have shown that PTCA, in the short term, relieves angina pectoris and objective evidence of myocardial ischemia as assessed by elec- trocardiography, by thallium scintigraphy and by measurement of coronary blood flow and myocardial metabolism.“-4

Regarding the long-term efficacy of PTCA, 1 point of concern is that in a substantial portion of successfully dilated patients, restenosis may develop associated with a recurrence of myocardial ischemia. The prevalence of restenosis is uncertain. Reported rates have varied from 14 to 47%.5-8 When restenosis does occur, the physician and patient are again faced with the options of medical, surgical or balloon catheter therapy.

For repeat PTCA to be of therapeutic value, one would desire a high likelihood of acute success when attempting the procedure, a low incidence of compli- cations and, importantly, a sustained increase in luminal diameter of the dilated site over the long term. With these considerations in mind, we reviewed the infor-

Address for reprints: David 0. Williams, MD, Division of Cardiology, Rhode Island Hospital, Providence, Rhode Island 02902.

mation within the NHLBI registry to determine the acute and chronic efficacy and safety of repeat PTCA for coronary restenosis.

Methods

A cohort of 1,880 patients in whom an initial PTCA was successful were identified from the 3,079 Registry patients in whom the procedure was attempted. PTCA was considered successful if it resulted in angiographic evidence of success in the absence of MI, death or emergency CABG.

Two hundred forty-one of the patients in whom PTCA was successful underwent a second PTCA procedure. PTCA was performed on the same arterial segment in 203 patients (84%) and on a different segment in 38 (16%). The former group represents patients in whom restenosis of the initially suc- cessfully dilated segment was the indication for the second procedure; these patients are the subject of the present report. The latter group were patients with multiple lesions in whom a “staged” procedure was performed.

Statistical analysis: Differences in proportion were ana- lyzed using the chi-square technique. Differences were con- sidered significant if p <0.05. Predictive value was defined as the ratio of true positives to true positives plus false positives.

Results

Eighty-seven percent of the patients who underwent repeat PTCA were men. Their mean age was 52 years. Ninety-six percent had class II to IV angina.g Six per- cent had undergone previous CABG and 18% had

32C

had a previous MI. Eighty-two percent had 1-vesse disease.

The mean interval from the first to the second PTCP. was 147 days (median 126) (Fig. 1). Only 19 patients hat, a repeat PTCA in less than 10 days, although 77% hat the second procedure within 6 months of the first.

Results of the acute outcome of repeat PTCA art, summarized in Table I and compared with those of al, patients who underwent an initial PTCA. The success rate of repeat PTCA was 85.2%, a value significant]!, higher than that of patients who underwent an initiai PTCA only. Inability to pass or dilate a lesion with a dilating catheter occurred less frequently among pa. tients who underwent repeat PTCA. Significant dif ferences were also observed in the prevalence of major complications. Of patients who underwent repeat PTCA, only 1.5% had a nonfatal MI and 2% required emergency CABG. No patient who underwent repeat PTCA died. The occurrence of any of these in-hospital complications was only one-third as frequent among patients who underwent repeat PTCA compared with those who underwent an initial PTCA (3.0 vs 9.3%).

Of the 173 patients in whom repeat PTCA was suc- cessful, 128 had their procedure performed before Oc- tober 1,1981, and were thus eligible for at least 1 year of follow-up (Table II). Information was obtained for 120 patients, for a completeness of follow-up of 94%. Eighty-seven patients had a maximum follow-up of less than 2 years. All but one was alive. Three-fourths of the patients (75.9%) did not require subsequent revascu- larization by either PTCA or CABG and did not have an MI. Nearly two-thirds of this subgroup of patients (48% of the entire l-year follow-up group) were free of angina. Fewer patients were available for 2 and 3 years of follow-up. No deaths occurred among these patients. The majority of these late follow-up patients did not have an MI or require additional revascularization procedures.

Sixty-two patients in the follow-up group (48%) un- derwent angiography. The mean interval from repeat PTCA to the time of follow-up angiography was 218 days. In 54 patients (87%), the interval was longer than 3 months.

Follow-up angiographic examinations were assessed regarding development of restenosis of the segment that was dilated twice (Table III). Restenosis was defined as either an increase of 30% or more in the severity of di- ameter of luminal narrowing or loss of at least half of the gain in improved luminal narrowing resulting from the second PTCA.

Restenosis was present in 21 patients (34%) in whom angiographic follow-up was available. Thus, 66% of the patients showed sustained improvement in the arterial segment that had initially restenosed after the first successful PTCA.

The relation between the symptom of chest pain at the time of follow-up and the angiographic results was assessed (Table IV). Twenty-four patients (39%) com- plained of chest pain. Eight of these patients (33%) did not have evidence of restenosis. Thus, the predicted accuracy of chest pain as an indicator for restenosis was

a 0 6.’ ] MEAN. MEDIAN: 147 126 Days Days

3 ill ‘7% Withio 200 Days

5 60‘ 3 I- .u Ll

/

2 2

a 40’

20 ‘- ~

1

0; I l- , . < 10 31-60 101-200 301-400 > 700 501-600

10-30 61-100 201-300 401-500 601-700

DAYS

FIGURE 1. Distribution of repeat PTCA procedures performed according to the clasped time after the first PTCA.

67%. Only 5 of 33 patients without chest pain had evi- dence of restenosis. The predictive accuracy of the ab- sence of chest pain for sustained angiographic im- provement was 87%. Thus, the absence of chest pain was more likely to predict the presence of sustained im- provement than was the presence of chest pain in pre- dicting development of restenosis.

Discussion

The results of this investigation indicate that patients who undergo repeat PTCA have baseline clinical char- acteristics similar to those of the large group of patients undergoing a single or an initial PTCA. The 2 groups are not distinguishable in terms of the presence of angina or history of MI or CABG.

Repeat PTCA was usually performed early in the course of follow-up after an initial successful PTCA. Most repeat procedures were performed within 6 months of the first. Repeat PTCA in this investigation was performed for restenosis of an initially successfully dilated arterial segment. The interval from PTCA to the

TABLE I immediate Outcome of Repeat Percutaneous Transluminal Coronary Angioplasty

Success Inability to

pass iesion Inability to

dilate lesion Nonfatal MI

MI, emergency CABG or death

Initial PTCA

Procedure (n = 3,079)

1881 (61.0%) 757 (24.7%)

256 (8.3%)

151 (5.0%) 200 (6.6%)

28 (0.9) 286 (9.5%)

Second Procedure

for Restenosis P (n = 203) Value

173 (85.2) <o.oi 13 (6.4%) <O.Ol

8 (3.9 %) <0.05

; 1;:;“:“; <0.05 00 <O.Ol

0 (0.0%) <O.Ol 6 (3.0%) <O.Ol

34C EFFICACY OF REPEAT PTCA

TABLE II Late Outcome of Patients in Whom a Repeat Procedure Was Successful

Duration of Follow-up

1 Year 2 Years 3 Years Total

No. of pts Event free Asymptomatic

C~;-; event CABG MI Death

87 (100%) 28 (100%) 5 (100%) 120 (100%) 66 (75.9%) 18 (64.3%) 4 (80%) 88 (73.3%) 42 (48.3%) 8 (44.4%) 0 50 (41.7%)

4 (4.6%) 1: (35.7%)

0 4 (3.3%) 1; ;;7i”/‘;o) 1(20%) 26 (21.7%)

00 0 1(0.8%) l(l.l%) 0” 0 1(0.8%)

development of clinical manifestations of restenosis, in most instances, is less than 4 months.7 Thus, the interval from an initial PTCA to the second PTCA is closely correlated to the time required for restenosis to be clinically manifest. Repeat PTCA was usually done soon after restenosis became clinically apparent.

The success rate of repeat PTCA was high and ex- ceeds that in a larger population of patients who un- derwent an initial or a single PTCA. At least 2 reasons may account for this finding. First, patients who un- dergo repeat PTCA are a highly selected cohort in that PTCA had been attempted once before and was suc- cessful. Thus, the anatomic characteristics of the cor- onary circulation of these patients was suitable for PTCA. Furthermore, assuming the same physician performed the second procedure, the physician ob- viously had the capabilities and equipment necessary to fulfill the requirements for a successful outcome. The second, albeit probably less significant, reason is that all cases were performed later in the learning experience of the operator compared with all initial cases.

Regardless of the reason for differences in the success rate of repeat PTCA compared with initial PTCA, the value of 85% is high. Thus, patients who present with restenosis are likely to have successful PTCA, at least for the short term, should they elect again to undergo the procedure.

TABLE III Angiographic Follow-Up After Repeat Percutaneous Transluminal Coronary Angioplasty

n %

No. of pts 62 100 Sustained Improvement 41 Restenosis 21 ::

TABLE IV Relation Between Chest Pain and Angiographic Findings After Successful Repeat Angioplasty

No Restenosis Restenosis Total

No chest pain 33 5 38 Chest pain 8 16 Total 41 21 :;

Mean duration of follow-up = 218 days.

Serious complications during repeat PTCA were rare and occurred less often than during initial PTCA pro- cedures. Undoubtedly, the low complication rate again was in part related to the fact that patients who un- derwent repeat PTCA had undergone a previous suc- cessful procedure. Although successful PTCA can be associated with a major complication (for example, MI resulting from occlusion of an arterial side branch), the prevalence of such complications is substantially lower than that in patients in whom PTCA is unsuccessful.10 Hence, preselection is probably the most important factor accounting for the high success rate and low complication rate during repeat PTCA for coronary restenosis.

Although repeat PTCA for restenosis has a high likelihood of success and a low risk of major complica- tion, it would not be of value if the second successful dilatation were not sustained for the long term. Because restenosis occurred shortly after the first successful PTCA, will it occur immediately after the second? This important question could best be answered if all of the Registry patients who underwent repeat PTCA had routine follow-up angiography and the results of such studies were available. The voluntary nature of the Registry, however, both in terms of patient and physi- cian obligations for fulfillment of follow-up evaluation and data acquisition, limits the degree to which the Registry can address detailed issues concerning late follow-up. Nevertheless, historical information per- taining to the patients who underwent repeat PTCA in whom at least 1 to 3 years had elapsed after the proce- dure was obtained in 94% of these patients. The mor- tality rate for the group was low (0.8%). Most patients did not require a subsequent revascularization proce- dure; MI was rare (0.8%). Nearly half of the patients were asymptomatic. Thus, in terms of mortality and de- velopment of MI, the frequency of such morbid events during the period of follow-up was low. These results compare favorably with those of patients with l-ves- sel CAD treated either medically or surgically.“-‘”

Angiographic information was available in half of the patients eligible for follow-up. Although in each of these patients restenosis had developed after the first PTCA, only 34% of the patients had restenosis after the second procedure. Thus, in two-thirds of the procedures, im- provement in luminal diameter of the arterial segment was sustained.

June 15. 1984 THE AMERICAN JOURNAL OF CARDIOLOGY Volume 53 35c

The patients in whom angiography was performed after repeat PTCA were further analyzed to determine the relation between the symptom of chest pain and the development of restenosis. Of the 62 patients, 24 (38%) complained of chest pain and 21 (33%) had restenosis. Although the prevalence of chest pain and restenosis was similar, some patients with chest pain did not have restenosis and vice versa. Thus, the predictive value of chest pain for the presence of restenosis was only 67%. Although restenosis did occur in the absence of chest pain, this was a rare event such that the absence of chest pain for predicting absence of restenosis was high-87%. Thus, chest pain occurring after repeat PTCA may or may not indicate the development of restenosis. Ab- sence of chest pain may be interpreted as usually indi- cating sustained improvement.

In summary, these data detailing the immediate and late effectiveness of repeat PTCA indicate that the procedure is of therapeut.ic value. Repeat PTCA has a high success and a low complication rate. The majority of patients do not experience subsequent restenosis and are free of angina. If repeat PTCA is applied as an in- tegral component of PTCA therapy, it has a significant impact on the overall effectiveness of PTCA (Fig. 2). According to Registry data, if 100 patients underwent a successful PTCA procedure, restenosis would develop in one-third.i4 If a second PTCA were performed in these patients, 28 would be successfully dilated. Eigh- teen patients with sustained improvement would be recovered from the restenosis group and added to the long-term success cohort. Thus, if PTCA is recom- mended for restenosis, patients who experience an ini-

tially successful PTCA can anticipate a rate of long- term success of approximately 85%‘.

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