Catheterization and Cardiovascular Diagnosis 17:75-79 (1989)

Acute Reocclusion During Percutaneous Transluminal Coronary Angioplasty: Immediate and

Long-Term Outcome

Kenneth I?. Buccino, Alan S. Brenner, MD, and Kevin F. Browne, MD

Acute total occlusion of a coronary artery during percutaneous transluminal coronary angioplasty (PTCA) has previously resulted in emergency surgical intervention (CABG). We retrospectively surveyed 21 1 elective procedures and 65 procedures for acute myocardial infarction (AMI). There were 42 patients (pts) [29 elective (14%) and 13 AM1 (20%)] In whom total occlusion occurred after initial dilation had been achieved. In 30 of 42 pts reangioplasty successfully reperfused the vessel. Ten patients (24%) required CABG and two (5%) were treated medically for AMI. Death occurred in 2 pts due to irreversible cardiogenic shock despite successful angioplasty. After 6 months follow-up 22 pts remained asymptomatic. It is concluded that aggressive redilation of total occlusions which develop during PTCA will frequently result in a successful angioplasty with a long-term restenosis rate comparable to uncomplicated angioplasty.

Key words: acute occlusion, complications, acute MI, outcome

INTRODUCTION

Since the introduction of percutaneous transluminal coronary angioplasty (PTCA) in 1977, the role of the technique has expanded greatly. Originally, PTCA was used only for proximal, noncalcific, subtotal stenosis in patients with single-vessel disease [ 11. Subsequent progress has shown that PTCA is a viable treatment option in patients with multivessel disease [2], multiple lesions in single vessels, narrowing of coronary artery bypass grafts [3], unstable angina pectoris [4,5], and both acute and recent total coronary occlusion [6].

The present study deals with the efficacy of immediate redilation in treating patients who develop total occlusion in the catheterization laboratory during a PTCA. This report includes patients who initially have subtotal oc- clusion and patients who initially have a totally occluded vessel in whom initial PTCA attempt establishes good flow but subsequently have redevelopment of total oc- clusion.

Although acute occlusion of a coronary artery may result from spasm or thrombosis, coronary dissection with development of an intimal flap is thought to be the most common cause during an angioplasty and often leads to emergency surgical revascularization. Marquis et al. showed that redilation of an acute reocclusion was a feasible approach for patients in whom a coronary artery was completely occluded by a presumed dissection [7]. This analysis of our experience with a similar approach in 42 patients establishes the favorable outlook

that can be achieved despite the development of acute reocclusion.

MATERIALS AND METHODS Study Group

Between July of 1983 and December of 1985, percu- taneous transluminal coronary angioplasty (PTCA) was performed in 276 patients at our institution. Using the grading scale from the Thrombolysis in Myocardial Infarction Study (TIMI), TIMI grade I1 or I11 [8] flow was either present or established initially, but was followed by total coronary artery occlusion during the procedure in 42 (15%) of these patients. This study group consisted of 37 males and 5 females with a mean age of 61 2 9 years (range 43-86).

Clinical Characteristics of the Study Group Twenty-two patients were classified as having single-

vessel coronary artery disease, seventeen had two-vessel

From the Cardiovascular Division, Watson Clinic, Lakeland, Florida.

Received August 18, 1987; revision accepted December 18, 1988.

Address reprint requests to Kevin F. Browne, M.D., P.O. Box 95000, Lakeland, FL 33804.

This research was performed under a grant from The Watson Clinic Foundation.

0 1989 Alan R. Liss, Inc.

76 Buccino et al.

TABLE I. Clinical Characteristics

No. of Patients

Sex Male Female Elective PTCA” Increased risk PTCA” Acute MI PTCA”

Age 42

61 k 9 years

37 5

22 7

13

”See text for specific descriptions.

disease, and three had three-vessel disease. Although 20 patients had multivessel disease, only 3 of the patients with multivessel disease received multivessel angioplas- ties. Seventeen patients had one vessel angioplasty because the patients had one of the following character- istics: patient presented with an acute myocardial infarc- tion (MI) (12 patients), patient was extremely unstable or had already endured a long procedure (3 patients), or occluded first vessel of a multivessel attempt (2 pa- tients).

In 22 patients PTCA was performed on an elective basis, in 13 as an emergency for acute MI, and in 7 under conditions of increased risk (Table I). Acute myocardial infarction was defined by typical electrocardiographic ST-segment elevation and a clinical picture consistent with an acute ischemic event. Total creatine phosphoki- nase (CPK) values greater than 300 and myocardial band (MB) fractions greater than 4% of the total CPK were also considered to be consistent with an acute MI. All 13 patients who were diagnosed with an acute myocardial infarction received 1.5 million units of intravenous streptokinase prior to catheterization.

Patients (pts) were considered to be at increased risk when their procedure was associated with at least one of the following features: unstable angina requiring intra- venous nitroglycerin (5 pts), hemodynamic instability (4 pts), unstable rhythm (2 pts), left ventricular ejection fraction less than 25% (1 pt).

The following predisposing factors for the develop- ment of coronary artery disease were categorized for each patient: hypertension, cigarette smoking, serum cholesterol above 200 mg%, diabetes mellitus, obesity, and an immediate family history of ischemic heart disease under age 65 years.

Catheterization procedure. All patients underwent percutaneous catheterization

from the right or left femoral artery using the Judkin’s technique. Standard cardiac catheterization techniques for opacification of the left and right coronary arteries and, in selected patients, left ventriculography in the right anterior oblique position were utilized [9].

Angioplasty procedure. PTCA was performed from the femoral artery in each

patient through a percutaneously placed arterial sheath. Right ventricular pacemakers were placed routinely via the right femoral vein to the right ventricular apex and set in a demand mode of 50 complexes per minute. Angio- plasty was performed using standard methods [ 101. When the balloon catheter was advanced to the ostium of an affected coronary artery, an angioplasty guidewire was advanced through it and across the stenosis. A balloon angioplasty catheter of appropriate size was advanced across the stenosis and dilated multiple times for variable durations and pressures. The initial inflation pressure was always 1 atm greater than the pressure required to obliterate balloon indentation. Balloon inf la- tion pressure and time varied for subsequent inflations. Following deflation an exchange wire was placed and the balloon was removed. No pressure gradients were used. Diagnostic angiography was then performed. All deci- sions on redilation were made based on the angiographic appearance of the vessel. If the angiographic appearance of the vessel was acceptable and the residual luminal diameter stenosis was reduced to less than 50%, the exchange wire was removed and diagnostic angiography was again performed. If reocclusion occurred the lesion was recrossed with a guidewire when possible and the above sequence repeated.

Equiprnen t used. In 64% of the patients in this study group a balloon

catheter from Advanced Catheter System (ACS) was used, while a SCIMED balloon catheter was employed in 26%, and a USCI Corporation balloon catheter was used in 9% of the patients. These figures are comparable with our overall data base, which shows the use of the Advanced Catheter System in 69% of the cases, the SCIMED system in 26%, and the USCI system used in 5%. Standard guidewires ranging from 0.014 through 0.018 inch diameter were employed, depending upon the anatomy and the size and type of balloon being used.

RESULTS Clinical Risk Factors

Occlusion during the procedure was not predicted by the presence of predisposing clinical risk factors of family history, hypertension, cigarette smoking, hyper- cholesterolemia, and diabetes mellitus. Thirteen patients had three or more of these factors, twenty-seven had either one or two, and the remaining two patients had no known predisposing factors for coronary artery disease. When compared with the overall population, the number of predisposing factors did not have a significant effect on the development of a total occlusion during the procedure.

Acute Reocclusion During PTCA 77

coronary lesions, and 3 of 4 patients (75%) with left circumflex lesions. Twelve patients could not be suc- cessfully redilated. Ten patients required emergency coronary bypass surgery and two were treated medically with evolution of myocardial infarction.

TABLE 11. Location of Occlusions During PTCA'

Study group (N = 42) Control Database (N = 234)

Vessel No of pts % of group No. of pts % of group LAD 18 43 105 45 RCA 20 48 87 31 LCX 4 10 42 18

*LAD = left anterior descending coronary artery; RCA = right coronary artery; LCX = left circumflex coronary artery.

Angiographic Characteristics The vessel which occluded during the procedure was

the right coronary artery (RCA) in 20 patients (48%), the left anterior descending (LAD) in 18 cases (43%), and the left circumflex (LCF) in 4 cases (10%). Table I1 shows that occlusion is slightly more likely to occur in the RCA, which agrees with Cowley's et al. conclusion that dissection is also more likely in the RCA [ 1 11. These differences only represent trends and are not statistically significant. The patients with two- or three-vessel dis- ease also occluded more often than the patients with single-vessel disease (P 5 0.02), regardless whether one or more vessels were attempted.

Table I11 lists characteristics of the lesions approached during angioplasty. The presence of a long lesion, intimal irregularity, multivessel disease, and eccentricity of the lesion are factors known to be associated with risk of PTCA complications and appear more frequently in this study group than with our overall database. How- ever, lesions occurring on a bend in the coronary artery did not produce the expected increase in occlusion rate. The presence of intraluminal thrombus was not evaluated in this retrospective study.

Females have been observed to experience complica- tions more often than males from PTCA [ 11. However, when compared to the 172 males and 62 females in our overall data base who had angioplasties without occlu- sion, males appear to occlude more often than females ( P 9 .05).

Forty cases involved the dilation of coronary arteries which had 90% or greater stenosis initially. Only two patients who entered the laboratory with less than 90% occlusion developed total occlusion during the proce- dure. Discrete and local dissection was noted to be associated with total occlusion in 40% of the cases (17/42), complicated dissection occurred in 17% (7/42), and no dissection was seen in 43% (18/42), as shown in Table IV. The presence of dissection was more common with occlusion than in our overall data base ( P I 0.02).

In 30 of the 42 cases (71%), the angioplaster success- fully redilated the occlusion to a stenosis of less than 50% (Table V). Successful redilation was accomplished in 12 of the 18 patients (67%) with left anterior descend- ing lesions, 15 of the 20 patients (75%) with right

Procedural Issues

When compared with the overall data base there was no significant difference in the maximum initial inflation pressure or time. Because of the development of acute occlusion the study patients required more inflations, longer inflation times and higher inflation pressures than the control group (P<O.Ol). The brand of balloon did not influence the development of acute occlusion. The number of balloon inflations ranged from 1 to 16 with a mean of 6 * 4. The maximum pressure used varied from 2 to 14 atm (9 atm k 2). Inflation durations ranged from 15 to 300 s with a mean of 64 s 2 65.

Hospital Course

None of the 30 patients successfully redilated under- went elective bypass surgery during the study period. Two patients experienced cardiogenic shock complicat- ing an acute MI prior to PTCA and expired despite successful PTCA in both cases. These hemodynamic deaths represent a 4.7% mortality rate in our study group, which is considerably higher than our 0.4% overall death rate for all other angioplasty patients (P<O.OOl) and is higher than for our acute MI group

Antiplatelet (aspirin or dipyridamole), antispasm (Dil- tiazem or nitrates), and heparin were administered rou- tinely to patients post-PTCA. Thirteen patients received all three drugs, thirteen received only antiplatelet and antispasm drugs, three received antispasm and heparin, three received only antiplatelet, four received only an- tispasm, four received only heparin, and one received no medications. The last patient expired before he left the laboratory. The numbers in these subgroups were too small to determine effect on long-term results statisti- cally.

(4.4%).

Myocardial Infarction

Of the 29 patients in the elective and increased risk groups, three suffered a myocardial infarction by both EKG and CPK-MB isoenzyme criteria (10%). Twelve other patients showed evidence of infarction only through CPK-MB analysis. Nine acute MI (AMI) pa- tients had CPK-MB and surface electrocardiographic evidence of an acute MI. Six patients developed patho- logic Q waves. CPK-MB data were not taken in one AM1 patient who expired.

78 Buccino et al.

TABLE 111. Technical Difficulty Factors

Increased risk Elective Study (%) Control (%) XZ

Long lesion 7 3 7 40 31 1.22 Lesion at a bend 0 0 2 5 6 0.11 Lesion very distal 0 0 0 0 0 0.0

Acute MI

Local intimal disruption 6 2 7 36 29 0.65 Diffuse intimal disruption 0 1 0 2 9 2.04

Lesion calcified 0 0 0 0 1 0.42 Lesion eccentric 7 6 14 64 54 0.82 Two vessel disease 8 1 8 40 22 6.52 Three vessel disease 1 1 1 7 9 0.16 Initial stenosis > 90% 13 7 20 95.2 70 4.20

TABLE IV. lntimal Dissection (42 Patients)

Discrete Complicated None seen Acute MI 4 1 8 Increased risk 2 3 2 Elective 11 3 8

17/42(40%) 7/42(17%) 18/42(43%)

TABLE V. Success Rate of Attempted Re-PTCA

Successful redilation unsuccessful % successful

Overall (42 pts) (30pts) (12pts) (71%) RCA (20 pts) 15 5 75 LCX (4 pts) 3 1 75 LAD (1 8 pts) 12 6 67 Acute MI (13 pts) 11 2 85

Elective (22 pts) 15 7 68 Increased risk (7 pts) 4 3 57

Follow-up Studies Clinical follow-up data were available for at least 6

months in all 28 patients who were successfully redilated and left the hospital in stable condition. Six patients (21%) experienced angina and one of these (4%) suffered a nonfatal MI. Treadmill stress testing was performed according to a standard Bruce Protocol in all 28 patients during the first 6 months of follow-up and six patients (21 %) were considered to be ischemic. Recatheterization was advised 3-6 months after the original PTCA if symptoms or objective evidence suggested ischemia. Eleven (39%) patients underwent recatheterization of whom eight were either symptomatic or were found to have an early ischemic exercise test. Five had no restenosis of their vessels. Five patients had developed restenosis at the site of the original lesion, and one developed a high-grade lesion in another vessel. Of the latter six patients, four were treated with a repeat PTCA, one was sent to CABG, and one with diffuse disease was treated medically. Twenty-two of 28 patients (79%) remained asymptomatic through the 6 months following dilation of the total occlusion during their original PTCA .

DISCUSSION

In reviewing the role of PTCA in the treatment of coronary artery disease, Block recently concluded that the incidence of coronary dissection and occlusion does not change with operator experience and that factors intrinsic to the procedure may be operative in producing these complications [I]. Our experience with acute occlusions in 42 patients of 276 undergoing PTCA from 1983 to 1985 (15%) is similar to the 13.6% quoted for acute coronary events in the NHLBI Registry [ 11 despite the more difficult case selection including acute myocar- dial infarction and multivessel disease. As reported in other studies, we found that PTCA was more likely to be complicated by acute occlusion in patients with multi- vessel disease and in arteries obstructed by long and eccentric lesions with an irregular intimal appearance. Lesions in the RCA also were more likely to develop an occlusion during a PTCA. Vessels with less than 90% stenosis were much less likely to develop total occlusion; 40/42 patients (95%) in this study had 290% luminal stenosis.

Our data did not suggest a higher incidence of total occlusion in women or in patients assessed to be at increased risk because of unstable angina, hemodynamic instability, unstable rhythm, or poor left ventricular function. Also, the type of balloon system used was not related to the occurrence of acute occlusion.

Patients presenting with acute myocardial infarction and unstable angina clearly need to be separated and subgrouped from patients undergoing elective PTCA, since lesions in acute MI patients generally, and unstable angina patients frequently, are associated with thrombus and pre-PTCA intimal disruption. The mechanisms of total occlusion during PTCA are likely to differ from the elective group. Our patients with acute myocardial in- farction were more likely to develop total occlusion than our elective and high risk (unstable angina) groups, but this tendency was not statistically significant (.25 > P > . lo).

Immediate redilation was achieved in 30 of 42 patients

(7 1 %) who developed total coronary occlusion during PTCA and in 29 of the 30 cases the residual luminal diameter stenosis was estimated to be less than 50%. While this figure is lower than the primary success rate of 85 -90% cited in contemporary reports tabulated by the NHLBI Registry and >90% in our own data base for elective angioplasty, it shows that redilation can be successfully accomplished in a considerable number of patients who would otherwise be brought to emergency CABG or suffer an acute MI.

In fact, the option of immediate redilation and access to emergency CABG supports an acceptance of an increasing frequency of acute occlusions. Our group is more willing to attempt PTCA in higher-risk patients, i.e., those with multivessel disease and patients with angiographic lesions that are far from ideal. These options have expanded our clinical decision-making to include older patients and patients with more advanced coronary disease.

Six month outcome did not seem to be compromised in the 28 patients who were successfully redilated for acute occlusion during PTCA. If the patients who are free of symptoms and have nonischemic treadmill tests after successful redilation are presumed to have patent arteries, the long-term success rate is 22/28 (79%), a figure comparable with the long-term primary success rate after 1 year of follow-up in the NHLBI Registry (72%).

Repeat PTCA, which has proven to be more success- ful than the initial procedure, was needed by 14% of patients in the NHLBI Registry and 9.5% of our patients. The likelihood of restenosis, the major shortcoming of PTCA, was less for patients in our study group than patients in the NHLBI Registry; 6 of our 28 followed patients (2 1 %) demonstrated this restenosis, while the NHLBI Registry reports a 33% restenosis rate [l]. This difference partially reflects the fact that only symptom- atic patients or patients with ischemic treadmills were recatheterized and patients with restenosis who have no symptoms remain undetected.

In the early years of PTCA, patients who developed total occlusion during a procedure frequently required emergency CABG or medical treatment for an acute myocardial infarction; attempts to reopen the vessel by PTCA were often very limited. In recent years experi- enced angioplasters have been much more aggressive and persistent in attempts to resolve this complication by

Acute Reocclusion During PTCA 79

PTCA rather than accept emergency CABG or acute myocardial infarction. This study clearly demonstrates that this approach is valid and can frequently yield a successful long-term result without additional risk to the patient.

ACKNOWLEDGMENTS

We are indebted to Ms. Patricia Pipkin for her exten- sive secretarial assistance in preparing this manuscript.

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