Percutaneous transluminal coronary angioplasty in acute myocardial infarction

Percutaneous transluminal coronary angioplasty (PTCA) has, in general, been restricted to therapy for patients with angina pectoris. Thrombolytic therapy and guide wire recanalization

have been used to recanalize coronary arteries in patients with evolving myocardial infarction. Recently we and others have examined the use of PTCA to recanalize the acutely occluded artery associated with the early evolving phase of myocardial infarction. PTCA was performed as

definitive therapy in eight patients with acute myocardial infarction. Seven of these had totally occluded arteries to the region of infarct. The infarct-related artery was open within 20 minutes

in each of these cases. PTCA recanalization resulted in evidence for reperfusion in each case. Residual stenoses either were not present or were minimal. The procedure was well tolerated.

These preliminary results suggest that PTCA may be a reasonable alternative to intracoronary

thrombolytic therapy in certain patients with acute evolving myocardial infarction. (AM HEART J

107:820, 1984).

Carl J. Pepine, M.D., Xavier Prida, M.D., James A. Hill, M.D., Robert L. Feldman, M.D., and C. Richard Conti, M.D. Gainesville, Flu.

Limitation of myocardial infarction size through salvage of ischemic myocardium in the region undergoing necrosis is the major goal in the manage- ment of acute myocardial infarction (AMI). The angiographic observation that the coronary artery supplying the infarcted region is occluded early after the onset of symptoms has led to attempts to reestablish blood flow.’ Attempts to restore flow by perforation of the occlusion by guide wire, thrombo- lytic agents, or coronary artery bypass surgery have been accompanied by resolution of chest pain, return of ST segments to baseline, an early peak of serum creatine kinase (CK), and, in some, improved ventricular wall motion.2-5 Issues concerning recur- ring angina, residual stenosis, hemorrhagic infarc- tion, and reocclusion continue to be debated relative to nonsurgical therapy. For these and other regions, the method for optimal reperfusion is open to question. Recently percutaneous transluminal coro- nary angioplasty (PTCA) has been proposed as initial therapy in AMI.

THROMBOLYSIS VS PTCA

Restoration of flow by thrombolytic agents administered directly into the coronary artery

From the Department of Medicine, Division of Cardiology, University of Florida. and the Veterans Administration Medical Center.

Reprint requests: Carl J. Pep&, M.D., Department of Medicine (Cardiol- ogy), University of Florida, JHM Health Center, Box J-277, Gainesville, FL 32610.

820

requires coronary artery catheterization. Although clinical results have been favorable, restoration of patency ranges from 64% to 95% .’ This wide vari- ability probably relates to the morphologic features of the occlusion. In AM1 the occlusion is a complex lesion composed of both old and recent thrombus in addition to other mechanical elements.8 Complica- tions arising from thrombolytic therapy are fre- quent. Hemorrhage is common but rarely life threat- ening. Hemorrhagic infarction, a result of ischemic damage and perhaps the thrombolytic agent, has been seen in some fatal cases and may be common among survivors.7 Finally, important residual steno- sis and early reocclusion commonly may require other, more direct revascularization procedures. For this reason Meyer et a1.s introduced the combined thrombolytic and angioplasty procedure. They sug- gested that this combination could save time and money by the use of some of the same catheteriza- tion supplies, in addition to laboratory time and personnel. The combined procedure would probably be less stressful than two separate procedures for the patient. Subsequently, Serruys et al.‘O demon- strated that although reocclusion during or shortly after thrombolytic therapy is not uncommon, no reocclusions or reinfarctions occurred when PTCA was added.

PTCA AS DEFINITIVE THERAPY IN AMI

Hartzler et al.6 extended this concept by perform- ing PTCA without prior thrombolytic therapy in 12

Volume 107

Number 4 PTCA in acute myocardial infarction 821

Table I. University of Florida experience with PTCA as initial therapy in AM1

Patient No. Age (yrjlsex

Time between

onset of symptoms and reperfusion

(hr:min) Location

% Stenosis *

Before PTCA After PTCA

Killip class

Before PTCA After PTCA

1 50/F 4:50 Inferior RCA 100 50 I I

2 58/F 3:45 Anterior LAD 100 10 III I

3 56/M 4:30 Inferior RCA 60 0 III I

4 58/M 630 Anterior LAD 100 30 III I

5 48/M 8:oo Anterior LAD 100 20 I I

6 39/M 400 Inferior RCA 100 35 I I

7 57/M 4:00 Inferior RCA 100 0 I I

RCA = Right coronary artery; LAD = left anterior descending coronary artery.

*Percent stenosis in diameter reduction.

patients. In 4 of the 12, total coronary artery occlu- sion was responsible for AMI; in eight patients, subtotal occlusion was found. In 11 of the 12 patients, PTCA was successful in providing prompt relief of chest pain, stabilization of the clinical course, and improvement in regional and global left ventricular function.

We used PTCA as definitive therapy for coronary artery recanalization in acute evolving myocardial infarction in seven patients ranging in age from 39 to 58 years (Table I). Four infarctions were inferior and three anterior. None of the patients had sustained a prior myocardial infarction. All but one patient had total occlusion of the coronary artery supplying the infarcted region. In each patient, PTCA promptly recanalized the artery within 20 minutes of intro- duction of catheters. The resulting residual stenosis ranged from 0% to 50%. Clinical evidence for reperfusion, such as complete relief of chest pain with rapid evolution of ECG and serum CK changes occurred in each patient.

POTENTIAL ADVANTAGES OF PTCA IN AMI

Our uncontrolled pilot results with PTCA as primary therapy in AM1 have been encouraging. The total time spent in the catheterization laborato- ry is relatively short and probably considerably shorter than that for elective transluminal angio- plasty. The reason is that penetration of the guide wire and/or balloon-catheter through the occluded region appears to be much easier than in cases in which PTCA is done electively for chronic angina. The material comprising the occlusion seems to be not only relatively soft but rapidly and easily di- lated, generally with relatively low pressure. Impor- tant residual stenoses were not seen after PTCA in these patients with AMI. In addition, our patients undergoing emergency PTCA for AM1 have not had

coronary artery bypass surgery as a standby if the procedure proved unsuccessful or complicated. Our reasoning is that in the patient with a 4- to 8- hour-old infarction, the risk of subsequent coronary artery bypass surgery 2 hours later could be high. The vessel is likely to be totally occluded proximal- ly, and the region is already undergoing infarction. The major complication leading to the need for emergency surgery in elective PTCA for angina is sudden total occlusion of the vessel with the threat of myocardial infarction. In our opinion little is to be gained by emergency surgery if the procedure is unsuccessful. In these patients already undergoing infarction, we make no attempt to dilate stenoses in other regions not involved with the infarction. Mon- itoring the patient’s clotting status after PTCA is considerably simpler than doing so after thrombo- lytic therapy. In our series there has been no signif- icant bleeding-in spite of the fact that several patients received small doses of intracoronary strep- tokinase after PTCA in an attempt to “clean up” the vessel that had angiographic characteristics suggest- ing residual thrombus. Pretreatment with steroids, a possible deleterious factor in the healing myocardial infarction, is not required if streptokinase is not used. Contraindications for thrombolytic therapy, such as stroke, bleeding, coagulation disorder, and previous exposure to streptokinase, are not contra- indications to PTCA.

CLINICAL IMPLICATIONS

Despite encouraging initial results, we do not know whether PTCA offers a definite benefit over other recanalization procedures in patients with acute infarction. Clearly, not every patient with an AM1 will be a candidate for revascularization by coronary angioplasty. Current clinical indications for attempting recanalization include continuing

822 Pepine et al. April, 1984

American Heart Journal

pain less than several hours in duration, with ECG evidence of ischemia. Technical considerations include location of the stenosis or totally occluded vessel and association of multiple-vessel disease. Some of these technical factors may preclude PTCA in favor of thrombolytic therapy or other manage- ment, such as coronary artery bypass surgery. In many cases of acute infarction, however, the ana- tomic characteristics of the totally or subtotally occluded vessel suggest that PTCA, as definitive therapy, is feasible-as suggested by our small series and the patients reported by Hartzler et a1.6 These results can form the background data necessary for larger studies and possible randomized trials com- paring PTCA without thrombolytic therapy and thrombolytic therapy alone or bypass surgery alone in management of patients with AMI. REFERENCES

1. DeWood MA, Spores J, Notske RN, et al: Prevalence of total

coronary occlusion during the early hours of transmural myocardial infarction. N Engl J Med 303897, 1980.

2. Ganz W, Buchbinder N, Marcus H, et al: Intracoronary thrombolysis in evolving myocardial infarction. AM HEART J 101:4. 1981.

3. Rentrop P, Blanke H, Karsch KR, et al: Changes in left ventricular function after intracoronary streptokinase infu- sion in clinically evolving myocardial infarction. AM HEART d 102:1188, 1981.

4. Mathey DG, Kuck K-H, Tilsner V, Krebber HJ, Bleifeld W: Nonsurgical coronary artery recanalization in acute transmu- ral myocardial infarction. Circulation 63:489, 1981.

5. Markis JE, Malagold M, Parker JA, et al: Myocardial salvage after intracoronary thrombolysis with streptokinase in acute myocardial infarction. Assessment by intracoronary thalli- um-201. N Engl J Med 305:777, 1981.

6. Hartzler GO, Rutherford BD, McConahay DR, Johnson WL, et al: Percutaneous transluminal coronary angioplasty with and without thrombolytic therapy for treatment of acute myocardial infarction. AM HEART J 106:965, 1983.

7. Brooks N: Intracoronary thrombolysis in acute myocardial infarction (editorial). Br Heart J 50:397, 1983.

8. Fulton WFM: The morphology of coronary thrombotic occlu- sions relevant to thrombolytic intervention. In Kaltenbach M, et al, editors: Transluminal coronary angioplasty and intracoronary thrombolysis. Berlin, 1982, Springer-Verlag. p 244.

9. Meyer J, Merx W, Schmitz H, Erbel R, et al: Percutaneous transluminal coronary angioplasty immediately after intra- coronary streptolysis of transmural myocardial infarction. Circulation 66:905, 1982.

10. Serruys PW, Wijns W, VanDenBrand M, Ribeiro V, et al: Is transluminal coronary angioplasty mandatory after success- ful thrombolysis? Quantitative coronary angiographic study. Br Heart J 50:257, 1983.