Angioplasty in Total Coronary Artery Occlusion

Transcription

1 lacc Vol. 3. NO REPORTS ON THERAPY Angioplasty in Total Coronary Artery Occlusion DAVID R. HOLMES, Jr., MD, FACC, RONALD E. VLIETSTRA, MD, FACC, GUY S. REEDER, MD, JOHN F. BRESNAHAN, MD, HUGH C. SMITH, MD, FACC, ALFRED A. BOVE, MD, HARTZELL V. SCHAFF, MD Rochester. Minnesota Percutaneous transluminal coronary angioplasty was attempted without streptokinase in 24 patients with total coronary artery occiusion but without acute transmural myocardial infarction. The maximal duration of occlusion was estimated to be 1 week or less in 10 patients, more than 1 to 4 weeks in 6, more than 4 to 12 weeks in 3 and more than 12 weeks in 5. Dilation ofthe occluded artery was attempted in the left anterior descending coronary artery in 17 patients, in the right coronary artery in 4 and in the circumflex coronary artery in 3. Angioplasty was successful in 13 patients (54 %): left anterior descending coronary artery in 59 %, right coronary artery in 50% and circumflex coronary artery in 33 %. In patients with successful dilation, there was a mean decrease in coronary artery stenosis from 100 to 23%. In the 19 patients whose occlusion was estimated to be of 12 weeks' duration or less, angioplasty was successful in 68%. In the five patients whose occlusion was estimated to be of more than 12 weeks' duration, dilation was not successful in any (p = 0.006). It is concluded that in selected patients with symptomatic coronary artery disease and recent coronary artery occlusion without associated acute myocardial infarction, percutaneous transluminal coronary angioplasty alone may be effective in restoring patency. Since its introduction in 1977, percutaneous transluminal coronary angioplasty has been used with increasing frequency in patients with symptomatic coronary artery disease (1-7). Although the technique was initially reserved for patients with a single discrete stenosis, experience has shown that it may be applied in selected patients with left main coronary artery narrowing, coronary artery bypass graft stenosis and multiple vessel coronary artery disease (4,8-13). Current criteria for elective coronary angioplasty, however, still include the presence of high-grade but subtotal coronary obstruction. This study deals with the feasibility of coronary angioplasty alone in a selected group of patients with total coronary artery occlusion without associated acute myocardial infarction in whom the duration of occlusion could be estimated. From the Division of Cardiovascular Diseases and Internal Medicine. and the Section of Thoracic. Cardiovascular. Vascular and General Surgery, Mayo Clinic and Mayo Foundation. Rochester. Minnesota. Manuscript received May ; revised manuscript received September accepted September Address for reprints: David R. Holmes Jr.. MD. Division of Cardiovascular Diseases and Internal Medicine, Mayo Clinic. 200 First Street SW. Rochester, Minnesota by the American College of Cardiology Methods Study group. Patient selection. From October 1979 to the end of November 1982, percutaneous transluminal coronary angioplasty was attempted after informed consent in 24 patients with total coronary artery occlusion without associated acute transmural myocardial infarction. No patient received streptokinase therapy. These 24 patients represent 10.4% of all patients undergoing attempted coronary angioplasty during this period at the Mayo Clinic. There were 20 men and 4 women with a mean age of 58.4 years (range 48 to 75). Clinical findings. All patients had prior angina pectoris (mean duration 50.5 weeks; range I to 260). Fifteen patients had had angina pectoris for 6 months or less. Thirteen patients were in New York Heart Association functional class IV, eight were in class III and three were in class II. Twelve patients had a definite increase in frequency and severity of angina pectoris within I month before evaluation. Although no patient had a documented evolving transmural acute myocardial infarction, four had a recent myocardial infarction from I week to I month before attempted dilation-three with a subendocardial infarction and one with a transmural myocardial infarction. No patient had documented coronary artery spasm /84/$3.00

2 846 HOLMES ET AL. lacc Vol. 3. No.3 Angiographic characteristics. Eighteen patients had undergone angiography before attempted dilation with identification of a high-grade lesion (mean stenosis 96% of the luminal diameter; range 90 to 99) that was thought to be technically suitable for angioplasty. In these patients, the time interval between documentation of the suitable lesion and attempted dilation was 11.2 weeks (range I day to 40 weeks). Six patients did not have previous angiographic documentation of a lesion thought to be ideally suitable for dilation. In four of these six patients, dilation was performed during initial coronary angiography after documentation of a total coronary occlusion. All four patients were undergoing angiography within I month of the onset of unstable angina pectoris refractory to medical therapy. In these patients, because oftheir clinical course, cardiovascular surgical coverage had been prearranged with the option of proceeding directly to coronary bypass graft surgery, depending on the results of angiography. Of the remaining two patients, one had total left anterior descending coronary artery occlusion at angiography 2 years before attempted dilation; the other had undergone a successful dilation of a high-grade distal right coronary artery stenosis 2 months previously. Angina returned after angioplasty, and at angiography the previously successfully dilated distal right coronary artery was found to be totally occluded. Fourteen patients had single vessel coronary artery disease and 10 had double vessel coronary artery disease (2: 50% stenosis ofthe luminal diameter in two major coronary epicardial vessels). The occluded vessel was the left anterior descending coronary artery in 17 patients, the right coronary artery in 4 and the circumflex coronary artery in 3. Collateral circulation. Collateral vessels that provided some degree of opacification of the course of the occluded coronary artery were seen in 20 of the 24 patients. In the remaining four patients, the course of the occluded distal vessel was known from the previous angiogram that had documented a patent vessel. Among the 20 patients with collateral channels, the collateral vessel originated from the contralateral coronary artery in 10, from the ipsilateral coronary artery in 4 and from both coronary arteries in 6. Estimated duration ofocclusion. The maximal potential duration of occlusion was estimated in 18 patients as the interval between the initial angiogram that had documented a subtotal stenosis and the time of attempted dilation of the now occluded coronary artery. In the four patients without a previous angiogram (all of whom had the initial onset of angina pectoris within 4 weeks before angiography), the duration ofocclusion was estimated from the onset ofsymptoms until the time of angiography. Of the remaining two patients, one had a known occlusion for 2 years; in the other, who had a previous dilation, angina had returned 2 weeks before reevaluation. The duration of occlusion was I week or less in 10 patients, I week to I month in 6 patients, I to 3 months in 3 patients and more than 3 months in 5 patients (Fig. I). Angioplasty procedure. Percutaneous transluminal coronary angioplasty was performed as previously described (3). Supplemental nitrates and calcium antagonists were administered during each procedure to exclude patients with occlusion due to coronary artery spasm. Success was defined as an improvement in the stenosis by 40% or more of the luminal diameter. From collateral filling of the distal vessel or from prior angiography, the course of the postocclusion vessel segment was assessed. An angle ofview was selected to give optimal resolution of the catheter tip orientation. A balloon catheter was selected and advanced into the zone of occlusion with injections of contrast medium used to locate the tip and degree of penetration and to confirm intraluminal position. Statistical analysis. The differences in outcome of dilation were tested by means of chi-square analysis. Results The occlusion was successfully passed and dilated in 13 patients (54%): 10 (59%) of the 17 patients with a left anterior descending coronary occlusion, 2 (50%) of the 4 with a right coronary artery occlusion and I (33%) of the 3 with a circumflex coronary artery occlusion. In these 13 patients, the mean stenosis after successful dilation was 23% (range 0 to 60) (Fig. 2, 3). In 10 of these 13 patients the mean pressure gradient across the stenosis was measured before and after dilation; in these 10 patients it was 52 before and 6 mm Hg after dilation. In II patients in whom dilation was unsuccessful, the most common reason for failure was inability to cross the occluded segment (eight patients). In one patient, the occluded vessel (circumflex) could not be entered. In the two remaining patients, the occluded segment was crossed and initially dilated but reocclusion occurred (one patient) or a high-grade persistent stenosis remained (one patient). Occlusion duration and outcome. The effect of the estimated duration of occlusion on the outcome of dilation Figure 1. Estimated duration of occlusion (abscissa) in 24 patients. See text for description. 10 rn c: Ql 8 :;:: ro a. 6 ' Ql.c E 2 ::l Z ",1 > 1 ~'5.4 Time (weeks) 5 >12

3 JACC Vol. 3, No.3 HOLMES ET AL. 847 Figure 2. Angiogram, right anterior oblique view, of the left coronary artery. A, Total occlusion of the middle left anterior descending artery. B, After dilation, there is visualization of the distal left anterior descending artery with minor residual stenosis. was assessed. In the 19 patients in whom the occlusion was estimated to be 12 weeks or less in duration, dilation was successful in 13 (68%). This contrasts with the five patients in whom the occlusion was estimated to be more than 12 weeks in duration, in none of whom dilation was successful (probability [p] = 0.006) (Fig. 4). Hospital course. Eight of the 11 patients with unsuccessful dilation underwent elective coronary artery bypass surgery, The remaining three patients, all with single vessel disease, continued with medical treatment. None of the II patients with unsuccessful dilation had evidence of coronary Figure 3. Angiogram, left anterior oblique view, of the left coronary artery. A, Total occlusion ofthe middle left anterior descending artery. B, After dilation, there is visualization of the distal vessel with 30% residual stenosis in the area of dilation. artery dissection, myocardial infarction, thromboembolic events, or coronary artery spasm, Of the 13 patients with an angiographically successful dilation and 40% or more improvement in stenosis of the luminal diameter, 3 had elevation of creatine kinase with a positive MB fraction after coronary angioplasty but without associated diagnostic electrocardiographic changes, A single patient experienced chest pain subsequent to the initially

4 848 HOLMES ET AL. JACC Vol. 3. No.3 <fl 10 C ~ 8 CO Q. 6 7,;:1 4 >1-s4 Time (weeks) Figure 4. Effect of estimated duration of occlusion (abscissa) on outcome of angioplasty in 24 patients. Discussion ~ Unsuccessful o Successful >4-';:12 successful coronary angioplasty. Repeat angiography documented a patent coronary artery but with evidence of a long intimal flap. This patient underwent coronary artery bypass surgery. During the postoperative period, an increase in creatine kinase with a positive MB fraction but without electrocardiographic changes was documented. Follow-up studies. Follow-up data were available in all patients. In patients with successful dilation at a mean follow-up of 7 months, one patient had required coronary artery bypass graft surgery for restenosis and one had required repeat dilation for restenosis. Seventy-seven percent of the patients were asymptomatic or had only atypical chest pain, whereas 23% had angina pectoris. In patients with unsuccessful dilation, eight had undergone coronary artery bypass graft surgery and three had continued with medical treatment. At a mean follow-up of 10.9 months, 73% were asymptomatic or had atypical chest pain, whereas 27% had angina pectoris. Of the 10 who underwent follow-up angiography, two had restenosis with greater than 40% increase in luminal diameter stenosis. In one patient with a 20% stenosis immediately after coronary angioplasty, at follow-up angiography 7 months later, the stenosis had increased to 40%. Initially, percutaneous transluminal coronary angioplasty was reserved for patients with symptomatic coronary artery disease and a proximal discrete, concentric subtotal stenosis in one coronary artery. Adherence to these selection criteria results in excellent success rates in two thirds or more of cases, but it significantly limits the proportion of patients with coronary artery disease who can be treated with this technique (1-7). With continued experience and technical improvements, clinical and angiographic selection criteria have been modified so that a larger proportion of patients with coronary artery disease might benefit from this approach (8-13). These criteria might be further broadened >12 to include selected patients with total coronary occlusion as documented in our experience. Progression of coronary stenosis to total occlusion. The patients presented represent a select group, and the extent to which our results can be applied in larger patient series is unclear. In practice, patients with symptomatic coronary artery stenosis technically suitable for dilation are identified at angiography. A variable interval usually elapses between this initial angiogram and coronary angioplasty, because the patient may require a trial of more intensive medical treatment or further consultation and referral. The coronary artery stenoses in these patients are usually angiographically and functionally very significant. Our experience is consistent with previous studies demonstrating that although progression of most coronary stenoses is slow and unpredictable, the most severe stenoses (generally > 90% reduction in diameter) have the greatest tendency to progress, often to complete occlusion (14,15). The progression in these lesions to total occlusion without clinical or electrocardiographic evidence of myocardial infarction has also been described (15). Importance of duration of occlusion. In the patients reported here, most occlusions were relatively recent, as judged from the interval between the previous angiogram and attempted dilation. A significant finding was that the maximal possible duration of occlusion was an important factor in determining the success of a dilation. In patients with an occlusion of less than 12 weeks' duration, a success rate of 68% was obtained. In contrast, in patients with an occlusion estimated to be of more than 12 weeks' duration, no successful dilations were achieved. The 100% failure in the latter group may be related to progressive organization and fibrosis in the occluded area, for the most common reason for failure was inability to cross the occluded segment. Role of collateral circulation. We presume that coronary collateral vessels were in part responsible for the wellmaintained regional myocardial function in the territory of completely occluded vessels in these patients (16,17). Other factors may play an important role (16,18,19). These factors include the time course of the occlusion, the amount of muscle mass perfused by the artery, the myocardial oxygen needs at the time of occlusion and the ability of the collateral flow to respond to physiologic stresses. The rapid disappearance of collateral vessels after successful coronary angioplasty as well as after saphenous vein bypass graft surgery has been documented (20,21). Precautions. Certain precautions should be taken with dilation of completely occluded arteries. First, perfusion of the myocardium in the distribution of the occluded vessel relies on the remaining coronary vessels. Because loss of these collateral vessels may be poorly tolerated, care must be taken to avoid trauma to the nondilated segments that supply these vessels. Second, it is important to visualize the course ofthe distal vessel and, thus, determine the proper

5 JACC Vol. 3. No.3 HOLMES ET AL. 849 route for the dilating catheter. This may be possible by reviewing films before the time of complete occlusion or by visualizing the distal vessel by way ofcollateral channels. Clinical implications. Criteria for patient selection and recommendations for coronary angioplasty continue to evolve. The patients reported here are a select group. In these patients, on the basis of our experience, total occlusion is not by itself a contraindication to coronary angioplasty. Successful dilation can be achieved in approximately two thirds ofselectedpatients with recent «12 weeks) total occlusion. In our experience, this situation occurs most commonly when a subtotal lesion suitable for dilation progresses to total occlusion in the interval between angiography and dilation. In these patients, if the interval is less than 12 weeks, dilation can be attempted with a reasonable chance of success and low likelihood of complications. The role of percutaneous transluminal coronary angioplasty without prior angiography in patients with the recent onset of unstable angina and a totally occluded artery (four patients in our series) requires further evaluation. For patients who have a recent onset of unstable angina that is refractory to medical management and who are scheduled for surgical revascularization immediately after angiography, dilation of the technically suitable coronary artery occlusions may be a reasonable alternative. References I. Griintzig A. Transluminal dilatation of coronary-artery stenosis (letter to the editor). Lancet 1978; I: Griintzig AR, Senning A, Siegenthaler WE. Nonoperative dilatation of coronary-artery stenosis: percutaneous transluminal coronary angioplasty. N Engl J Med 1979;30 1: Vlietstra RE, Holmes DR Jr, Smith HC, Hartzler GO. Orszulak TA. Percutaneous transluminal coronary angioplasty: initial Mayo Clinic experience. 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