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Coronary angioplasty in patients with prior coronary artery bypass grafting
International Elsevier
CARD10
333
Journal of Cardiologv, 28 (1990) 333-340
01104
Coronary angioplasty in patients with prior coronary artery bypass grafting T.M. Kolettis, H.C. Miller and D.P. De Bono * Department (Received
of Cardiology, 29 September
The Royal Infirmaty,
1989; revision
Kolettis TM, Miller HC, De Bono DP. Coronary grafting. Int J Cardiol 1990;28:333-340.
angioplasty
accepted
Edinburgh, UK. 20 March
in patients
1990)
with prior coronary
artery bypass
We studied the clinical and angiographic outcome of patients with prior coronary arterial bypass grafting who underwent percutaneous transluminal coronary angioplasty at the Royal Infirmary of Edinburgh. Over a 4 year period, 47 patients with prior bypass surgery underwent angioplasty of 23 stenotic graft sites and 37 stenotic sites of native vessels. The procedure was performed a mean of 31.3 months after surgery for recurrence of symptoms refractory to maximal medical treatment. Satisfactory angiographic results were achieved in 42 patients (58 stenotic grafts or native vessels). At a median follow up period of 18 months, 20 patients were symptomatically improved, but 22 patients experienced recurrence of symptoms a mean of 4.7 months after angioplasty, despite a good initial angiographic result. Overall, 4 patients had a repeat bypass grafting and 9 patients had a repeat angioplasty. Angioplasty can be used as an alternative to a repeat operation in patients with prior bypass grafting who experience recurrence of symptoms. Initial success rates are high and complication rates low. Restenosis or development of new lesions in the native circulation, and/or in the grafts, remain significant problems. Patients with a long asymptomatic interval (> 6 months) between the bypass operation and recurrence of symptoms are more likely to have better long-term results after successful angioplasty, perhaps because of slower progression of atherosclerotic heart disease. Key words: sis rates
Percutaneous
transluminal
coronary
angioplasty;
Introduction Since the introduction of the internal mammary coronary arterial anastomosis in 1967 [l], and the
Correspondence to: Professor D.P. de Bono, Dept. of Cardiology, Glenfield General Hospital, Groby Road, Leicester LE3 9QP, U.K. * Present address: Dept. of Cardiology, University of Leicester, U.K.
0X7-5273/90/$03.50
0 1990 Eisevier Science Publishers
Coronary
arterial
bypass
grafting;
Resteno-
use of saphenous vein grafts in 1968 [2], coronary arterial bypass grafting has been widely used in the treatment of ischaemic heart disease. It has become clear, nonetheless, that this is a palliative rather than a curative treatment. The progression of atherosclerotic disease in the coronary circulation, in the grafts, or in both, results in recurrence of angina1 symptoms in approximately 5% of patients annually [3,4]. Patients with severe recurrent angina after coronary bypass grafting who do not respond to
B.V. (Biomedical
Division)
334
medical treatment are potential candidates for a repeat operation. Unfortunately, this is technically more difficult, and gives less satisfactory results than the primary operation, while mortality and morbidity rates are higher than for the primary operation [5-71. An attractive alternative approach to the problem is offered by angioplasty of either native vessels, or grafts, or both. In this study we report our experience with the use of angioplasty in patients with prior coronary arterial bypass grafting.
Methods The computerised angioplasty records, clinic notes and angiograms of patients with prior coronary arterial bypass surgery who subsequently underwent percutaneous transluminal coronary angioplasty in the Royal Infirmary of Edinburgh during the period November 1984 to November 1988 were reviewed (during this period 1,450 patients underwent coronary bypass graffting in our centre). It is our policy to repeat coronary angiography in any patient who has had clinically unsatisfactory results from coronary bypass grafting if medical treatment fails to control symptoms. Angioplasty was selected as an alternative to repeat bypass grafting if coronary angiography demonstrated lesions which were thought to be responsible for the symptoms and were considered amenable to angioplasty. Diffuse “atheromatous” disease of a graft more than 1 year old, manifested by multiple shaft irregularities and narrowings, was regarded as a contraindication to angioplasty, as were unprotected stenoses of the left main coronary artery and severe three vessel disease with no grafts remaining patent. Angioplasty was performed by two cardiologists using a femoral approach, a standard long guidewire technique and wire guided balloon catheters. Inflations were continued until angiography (after withdrawal of the balloon) showed a satisfactory result defined as a reduction of more than 50% of the maximum diameter stenosis, or until the patient developed symptoms which necessitated termination of the procedure.
statistics Significance of difference was assessed by Student’s t-test for continuous variables or chi square analysis, after Yates’ correction, for events and patient numbers.
Results Forty-seven patients were analysed; 38 were male. The mean age was 55.9 years (range 24-74 years). At the time of surgery, 6 patients had single-vessel disease, 23 had two-vessel disease, 13 had three-vessel disease, and 5 had more than three vessel disease. Of the patients, 2 had undergone previous coronary artery bypass grafting, 2 had undergone two angioplasties each and a further 3 had undergone one angioplasty each prior to surgery. Grafts were placed on 114 vessels (39 on left anterior descending arteries, 26 on right coronary arteries, 31 on obtuse marginal arteries, 14 on diagonal arteries, and 4 on intermediate arteries). All patients had experienced recurrence of symptoms refractory to maximal medical treatment a mean period of 19.8 months after operation. Angioplasty was performed a mean of 31.3 months after bypass surgery. Sixty-four stenotic sites were identified and, in 60 of them (93.7%) the stenosis was successfully crossed. These included 23 sites within grafts (5 proximal anastomoses, 5 proximal graft sites, 1 mid-graft site, 4 distal graft sites and 8 distal anastomoses) and 37 sites within native vessels (6 in right coronary arteries, 15 in left anterior descending arteries, 3 in diagonal arteries, 11 in circumflex arteries, 1 in an obtuse marginal artery and 1 in a posterolateral artery). Of these native vessels, 23 were supplied by grafts (1 right coronary artery, 14 left anterior descending arteries, 2 diagonal arteries, 1 obtuse marginal artery, 1 posterolateral artery. The lesions could not be crossed in 4 native vessels (2 right coronary arteries, 1 circumflex artery, 1 obtuse marginal artery). All lesions were entered via the native vessel and not via a graft. One patient had a cardiac arrest during the third balloon inflation and was subsequently suc-
335
cessfully resuscitated. Two patients had chest pain which responded to nitrates and opiate. There were no other complications. Initial success, as judged angiographically, was achieved in 42 patients (89.3%) or 58 stenotic sites (90.6%) (Fig. 1). Of the 5 patients with technically unsuccessful angioplasty, or an unsatisfactory result as judged angiographically, 2 had repeat surgery, and no further intervention was possible in the remaining 3. The patients were followed up clinically at 3month intervals. The median duration of follow up was 18 months (range 3-49). During the period of follow-up, 1 patient (who had had an unsuccessful angioplasty) died. Benefit from angioplasty was achieved in 20 patients: 13 were symptomatically much improved (from Canadian Cardiovascular Society Functional Classification Criteria Class III-IV to Class I-II), and 7 patients were still experiencing angina but less severe than prior to their operation (from Class IV to II or III). In 22 patients, however, the benefit from angioplasty had been lost a mean of 4.7 months after the procedure despite a satisfactory initial angiographic result. Sixteen of them had repeat coronary angiography performed a mean of 10.2 months after angioplasty, with the results shown in Table 1. There was no significant difference in the rates of restenosis for grafts and for native vessels, nor was it possible to identify any site with a particular predilection for restenosis.
TABLE
Results of repeat coronary angiography unsatisfactory clinical response.
5 Patients unsuccessful PTCA r42 Patients (58 sites) Anglographic Success
Recurrence of stenosis in a graft Recurrence of stenosis in a native vessel Recurrence of stenosis in a native vessel + a new lesion in a native vessel Good result from previous angioplasty to a graft + new lesions in a graft Good result from previous angioplasty to a native vessel + new lesion in a native vessel New proximal lesion in a graft previously angioplastied Good result from angioplasty to graft; already occluded graft responsible for symptoms
2 6
20 Patients improved
9 Repeat PTCA
2 Repeai Surgery
11 Medical Rx
Fig. 1. Results of angioplasty following coronary arterial bypass grafting. PTCA = percutaneous transluminal coronary angioplasty; Rx = treatment.
2 2 2 1 1
Of the 22 patients with recurrence of symptoms, no further intervention was taken in 11 patients, 2 patients underwent a repeat bypass operation and 9 patients had a repeat angioplasty (Fig. 1). The mean asymptomatic interval between bypass surgery and first angioplasty for the patients with a good outcome after angioplasty was 26.9 months. This differed significantly when compared to the same interval for patients with a poor outcome after angioplasty, which was 12.4 months (P < 0.05). Similarly, the clinical outcome after angioplasty was compared between patients who experienced recurrence of symptoms early
2
Relation between outcome after angioplasty and time of return of symptoms after coronary bypass grafting.
I
I
with an
No. of pts.
Improved after PTCA
1 late death 2 repeat surgery
FOLLOW-UP 18 MONTHS
in 16 patients
Results
TABLE 47 Pattents wth Postoperative Angina
1
Early ( < 6 months) recurrence of symptoms after CABG Late ( > 6 months) recurrence of symptoms after CABG Total X = 6.86 angioplasty;
Not improved after PTCA
3
13
17
9
20
22
after Yates’ correction; CABG = grafting.
P < 0.01. PTCA
=
336 TABLE 3 Characteristics of patients with technically successful angioplasty.
Age Sex Smoking habit
N >5 <5 S
Improved after lWZA (n=20)
Not improved after F’TCA (n = 22)
59.3 f 9.44 15M 5F 4 10 6 0
53.2 k 11.53 18M 4F 3 8 10 1
Total cholesterol
6.57 + 1.50
6.54+
(mmol/l) Triglycerides
2.2 f1.06
2.9 + 1.52
0.05 < P i 0.1 NS NS
1.12
NS 0.05 < P i 0.01
(mmol/l) N = life-long non-smokers; > 5 = ex smokers, stopped more than 5 years prior to F’TCA; < 5 = ex smokers, stopped less than 5 years prior to ETCA; S = smokers; NS = no statistically significant difference; F’TCA = angioplasty.
( < 6 months) after surgery and those with late (> 6 months) recurrence of symptoms. There was a statistically significant difference in outcome after angioplasty, favouring patients with late recurrence of symptoms after surgery (P < 0.01, Table 2). The characteristics of the two groups of patients with different clinical outcome after angioplasty are shown in Table 3. There was no statistically significant difference in sex, smoking habit or total cholesterol values (at the time of angioplasty) between them. Patients with a poor outcome tended to be younger and tended to have higher levels of triglycerides (at the time of angioplasty) but none of these differences reached statistical significance. Unfortunately, information on the lipid status at the time of surgery was not available to us. TABLE 4 Relation of long-term clinical outcome after first graft angioplasty to “age” of graft. No. of pts. Old grafts (‘1
year)
New grafts (< 1 year)
<
<
Clinically improved Clinically not improved or angiographic recurrence Clinically improved Clinically not improved or angiographic recurrence
X = 5.09 (after Yates’ correction);
P i 0.05.
8 1 4 9
Comparison of the clinical or angiographic outcome of angioplasty to “old” (> 1 year) grafts with the outcome of angioplasty to “new” (< 1 year) grafts showed a statistically significant better outcome in old grafts (Table 4). Discussion Aetiology of recurrence of symptoms after coronary arterial bypass surgery
Recurrence of angina after coronary arterial bypass grafting is a complex clinical problem which may be due to several mechanisms. A very rapid recurrence of symptoms (within one month) may be due to technical problems, such as too large an aortotomy [8], or may be a result of incomplete revascularisation, graft failure [9] or total occlusion of grafts secondary to thrombosis [lO,ll]. The latter probability accounts for most of the cases. Angiography may be helpful in detecting technical problems, and sometimes these have a characteristic appearance (such as a constricted distal anastomosis, or shaft narrowing suggestive of thrombus in a valve pocket). Other causes of early recurrence of symptoms include the graft being placed on the wrong vessel, or misdiagnosing oesophageal or skeletal pain as angina. We do not believe these causes applied in the present study. Late recurrence of symptoms (after six months) is more likely to be a result of intimal fibromuscu-
331
lar proliferation in the grafts or progression of atherosclerosis in either the native circulation or in the grafts [9,11]. The rate of progression of atherosclerosis varies between individuals, and probably varies from time to time within the same individual. A number of predictors of the rate of development of atherosclerotic coronary arterial disease have been identified [12-141. Attention has previously been drawn to the need for control of risk factors for atherosclerosis in patients undergoing bypass grafting [15,16]. Initial success and complications
In our series, a satisfactory angiographic result was achieved in 89.3% of patients. Other studies [B-lo, 17-241 have also reported similar high initial success rates (75-95%). The complication rate has been low, again reflecting the experience of others [8-10,17-19,2123]. This rate is considerably lower than the complication rates of a repeat bypass graft, which carries a risk of perioperative myocardial infarction of 2-12% and mortality rates of l-17% [19]. Recurrence of symptoms after percutaneous luminal coronary angioplasty
trans-
We report a rate of 52.3% of recurrence of symptoms after technically successful angioplasty at a median follow up interval of 18 months. Similar rates have been reported by others [B10,17-20,22,25]. Graft restenosis. Some workers [8,9,26,27] have found a higher incidence of restenosis after angioplasty in proximal compared to distal anastomotic sites. We could not confirm this finding, and neither could others [19], but caution is needed in interpreting small numbers. An initially unexpected finding in our present series was a higher long-term success rate after angioplasty of old grafts (in place for more than one year). Several workers [11,19,27] have drawn attention to the dangers of atherothromboembolism after angioplasty of old grafts, which may have a friable and unstable pseudo-intima. We
would agree with these warnings, and advise very careful evaluation before undertaking angioplasty in grafts older than 1 year. It has been suggested that different mechanisms of angioplasty may operate in grafts of different ages [28], with stretching predominating in younger grafts and atherosclerotic plaque “fracture” in older ones. In our own series, despite the higher risk of restenosis in young grafts, repeat angioplasty was often feasible.
Restenosis of native vessels. It should be remembered that patients are likely to be selected for coronary arterial bypass surgery in the first instance because the lesions in their native vessels are relatively unattractive for angioplasty. Ernst et al. [17] found that 46% of patients with prior coronary arterial bypass surgery were free of symptoms 5 years after successful angioplasty, a rate which was significantly lower than for patients undergoing angioplasty as a primary procedure (79%). In their experience, angioplasty of “new” stenoses in the native circulation in patients with prior bypass surgery did not yield as good an outcome as in those who had not undergone previous surgery. They suggested that this can be partially explained by the higher incidence of progression of the disease elsewhere in the native circulation in patients with previous operations. Accelerated progression of atherosclerotic heart disease in patients with prior bypass surgery may be due to inadequate control of risk factors, but bypassing vessels with significant 129-311 or even minimal [32] lesions has been shown to accelerate atherosclerosis in the native circulation, possibly because of rheological factors [29,33]. The symptom-free interval after surgery is likely to reflect the rate of progression of atherosclerotic heart disease. We found that patients with late (> 6 months) recurrence of symptoms after surgery have a lower risk of recurrence of angina after angioplasty, compared to patients with a shorter (less than six months) symptom-free interval. Unfortunately, data are not available for us to attempt correlation between early symptom recurrence and failure to control atheroma risk factors.
338
In
conclusion,
despite the relatively high restenosis rate, angioplasty remains an attractive first-line procedure in patients who develop recurrent angina after coronary bypass grafting. From our experience in the present series we would emphasize three points. First, patients with a rapid progression of disease in their native vessels have a poor outcome. Vigorous efforts should be made to reduce risk factors in such patients both before and after bypass grafting. Second, patients with early stenosis within grafts usually have an excellent early response to angioplasty, but the stenoses tend to recur and repeat angioplasty is often needed. Finally carefully selected patients with a stenosis in an “old” graft may respond well to graft angioplasty. References 1 Kolessov VI. Mammary artery - coronary artery anastomosis as method of treatment for angina pectoris. J Thorac Cardiovasc Surg 1967;54:535-544. 2 Favaloro RG. Saphenous vein auto graft replacement of severe segmental coronary artery occlusion: operative technique. Ann Thorac Surg 1968;5:334-339. 3 Campeau L, Lesperance J, Hermann J, Corbara F, Grondin CM, Bourassa MG. Loss of the improvement of angina between 1 and 7 years after aortocoronary bypass surgery. Circulation 1979;6O(suppl l):l-5. 4 Seides SF, Borer JS, Kent KM, Rosing DR, McIntosh CL, Epstein SE. Long-term anatomic fate of coronary artery bypass grafts and functional status of patients five years after operation. N Engl J Med 1978;298:1213-1217. A, Kemp HG, Jr, Green GE. Reoperation for 5 Cameron coronary artery disease: 10 years of clinical follow-up. Circulation 1988;78(suppl 1); 158-162. 6 Fosler ED, Fisher LD, Kaiser GC, Myers WO. Comparison of operative mortality and morbidity for initial and repeat coronary artery bypass grafting: the Coronary Artery Surgery Study (CASS) registry experience. Ann Thorac Surg 1984;38:563-570. 7 Schaff HV, Orszulak TA, Gersh BJ, et al. The morbidity and mortality of reoperation for coronary artery disease and analysis of late results with use of actuarial estimate of event-free interval. J Thorac Cardiovasc Surg 1983;85:508513. 8 Dorros G, Johnson WD, Tector AJ, Schmahl TM, Kalush SL, Janke L. Percutaneous transluminal coronary angioplasty in patients with prior coronary artery bypass grafting. J Thorac Cardiovasc Surg 1984;87:17-26. P. PTCA: 10 years’ 9 Chokshi SK, Meyers S, Abi-Mansour experience. Prog Cardiovasc Dis 1987;30:147-210. 10 Ford WB, Wholey MH, Zikria EA. et al. Percutaneous transhuninal angioplasty in the management of occlusive
11
12
13
14
15
16
17
18
19
20
21
22
23 24
disease involving the coronary arteries and saphenous vein bypass grafts. J Thorac Cardiovasc Surg 1980;79:1-11. Saber RS, Edwards WD, Holmes DR Jr, Vlietstra RE, Reeder GS. Balloon angioplasty of aortocoronary saphenous vein bypass grafts. A histopathologic study of six grafts from five patients, with emphasis on restenosis and embolic complications. J Am Co11 Cardiol 1988;12: 1501-1509. Barth JD, Jansen H, Kromhout D, Reiber JHC, Birkenhager JC., Amtzenius AC. Progression and regression of lumen coronary atherosclerosis. The role of lipoproteins, lipases and thyroid hormones in coronary lesion growth. Atherosclerosis 1987;68:51-58. Kannel WB. D’Agostino RB, Belanger AJ. Fibrinogen, cigarette smoking and risk of cardiovascular disease: insights from the Framingham Study. Am Heart J 1987;113: 1006-1010. Kannel WB. Eaker ED. Psychosocial and other features of coronary heart disease: insights from the Framingham Study. Am Heart J 1986;112:1066-1073. Bourassa MG, Campeau L, Lesperance J, Solymoss C. Atherosclerosis after coronary artery bypass surgery. Results of recent studies and recommendations regarding prevention. Cardiology 1986;73:259-268. Campeau L, Enjalbert M, Lesperance J, et al. The relation of risk factors to the development of atherosclerosis in saphenous vein bypass grafts and the progression of disease in the native circulation. N Engl J Med 1984;311:13291332. Ernst SMPG, van der Feltz TA, Ascoop CAPL et al. Percutaneous transluminal coronary angioplasty in patients with prior coronary artery bypass grafting: long term results. J Thorac Cardiovasc Surg 1987;93:268-275. Reeder GS, Bresnahan JF, Holmes DR Jr, et al. Angioplasty for aortocoronary bypass graft stenosis. Mayo Clin Proc 1986;61:14-19. Cote G. Mvler RK, Stertzer SH, et al. Percutaneous transluminal a&ioplasty of stenotic coronary artery bypass grafts: 5 years’ experience. J Am Co11 Cardiol 1987;9:8-17. Corbelli J, Franc0 I, Hollman J, Simpfendorfer C, Galan K. Percutaneous transluminal coronary angioplasty after previous coronary artery bypass surgery. Am J Cardiol 1985;56:398-403. King JF, Dorros G, Lewin RF. The acute outcome of coronary angioplasty in patients with multiple prior bypass surgeries (abstract). Eur Heart J 1987;8(suppl 2):209. Wittenberg 0, Fajadet J, Pouchelon E, Marco J. Transluminal coronary angioplasty in patients with prior coronary artery bypass surgery. Immediate results and long-term follow up (abstract). Eur Heart J 1987;8(suppl 2):216. Hartzler GO. Role of angioplasty to complement bypass surgery (abstract). Eur Heart J 1987;8(suppl 2):238. Plokker HWM, Ernst SMPG, Bal ET, et al. Restoring the function of a proximally stenosed or occluded sequential aortocoronary venous graft by PTCA of a bypassed native vessel: the “back-door technique”. Eur Heart J 1988;9: 1098-1103.
339 25 El Gamal M. Bonnier H, Michels R, Heijman J, Stassen E. Percutaneous transluminal angioplasty of stenosed aortocoronary bypass grafts. Br Heart J 1984;52:617-620. 26 Douglas JS Jr, Gruentzig AR, King SB et al. Percutaneous transluminal coronary angioplasty in patients with prior coronary bypass surgery. J Am Co11 Cardiol 1983;2:745754. 27 Block PC, Cowley MJ, Kaltenbach M, Kent KM, Simpson J. Percutaneous angioplasty of stenoses of bypass grafts or of bypass graft at anastomotic sites. Am J Cardiol 1984;53:666-668. 28 Wailer BF. Rothbaum DA, Gorfinkel HJ, Ulbright TM, Linnemeier TJ, Berger SM. Morphologic observations after percutaneous transluminal balloon angioplasty of early and late aortocoronary saphenous vein bypass grafts. J Am Co11 Cardiol 1984;4:784-792. 29 Aldridge HE. Trimble AS. Progression of proximal coronary artery lesions to total occlusion after aortocoronary saphenous vein bypass grafting. J Thorac Cardiovasc Surg 1971;62:7-17.
30 Griffith LSC, Aschuff SC, Conti CR, et al. Changes in intrinsic coronary circulation and segmental ventricular motion after saphenous vein coronary bypass graft surgery. N Engl J Med 1973;288:589-595. 31 Levine JA, Bechtel DJ. Gorlin R, et al. Coronary artery anatomy before and after direct revascularization surgery: clinical and tine arteriographic studies in 67 selected patients. Am Heart J 1975;89:561-570. 32 Cashin WL, Sanmarco ME, Nessim SA, Blankenhorn DH. Accelerated progression of atherosclerosis in coronary vessels with minimal lesions that are bypassed. N Engl J Med 1984;311:824-828. 33 Kakos GS, Oldham HN Jr, Dixon SH Jr, Davis RW, Hagen PO, Sabiston DC Jr. Coronary artery haemodynamics after aortocoronary artery vein bypass: an experimental evaluation. J Thorac Cardiovasc Surg 1972:63:849-853.
CARD10
333
Journal of Cardiologv, 28 (1990) 333-340
01104
Coronary angioplasty in patients with prior coronary artery bypass grafting T.M. Kolettis, H.C. Miller and D.P. De Bono * Department (Received
of Cardiology, 29 September
The Royal Infirmaty,
1989; revision
Kolettis TM, Miller HC, De Bono DP. Coronary grafting. Int J Cardiol 1990;28:333-340.
angioplasty
accepted
Edinburgh, UK. 20 March
in patients
1990)
with prior coronary
artery bypass
We studied the clinical and angiographic outcome of patients with prior coronary arterial bypass grafting who underwent percutaneous transluminal coronary angioplasty at the Royal Infirmary of Edinburgh. Over a 4 year period, 47 patients with prior bypass surgery underwent angioplasty of 23 stenotic graft sites and 37 stenotic sites of native vessels. The procedure was performed a mean of 31.3 months after surgery for recurrence of symptoms refractory to maximal medical treatment. Satisfactory angiographic results were achieved in 42 patients (58 stenotic grafts or native vessels). At a median follow up period of 18 months, 20 patients were symptomatically improved, but 22 patients experienced recurrence of symptoms a mean of 4.7 months after angioplasty, despite a good initial angiographic result. Overall, 4 patients had a repeat bypass grafting and 9 patients had a repeat angioplasty. Angioplasty can be used as an alternative to a repeat operation in patients with prior bypass grafting who experience recurrence of symptoms. Initial success rates are high and complication rates low. Restenosis or development of new lesions in the native circulation, and/or in the grafts, remain significant problems. Patients with a long asymptomatic interval (> 6 months) between the bypass operation and recurrence of symptoms are more likely to have better long-term results after successful angioplasty, perhaps because of slower progression of atherosclerotic heart disease. Key words: sis rates
Percutaneous
transluminal
coronary
angioplasty;
Introduction Since the introduction of the internal mammary coronary arterial anastomosis in 1967 [l], and the
Correspondence to: Professor D.P. de Bono, Dept. of Cardiology, Glenfield General Hospital, Groby Road, Leicester LE3 9QP, U.K. * Present address: Dept. of Cardiology, University of Leicester, U.K.
0X7-5273/90/$03.50
0 1990 Eisevier Science Publishers
Coronary
arterial
bypass
grafting;
Resteno-
use of saphenous vein grafts in 1968 [2], coronary arterial bypass grafting has been widely used in the treatment of ischaemic heart disease. It has become clear, nonetheless, that this is a palliative rather than a curative treatment. The progression of atherosclerotic disease in the coronary circulation, in the grafts, or in both, results in recurrence of angina1 symptoms in approximately 5% of patients annually [3,4]. Patients with severe recurrent angina after coronary bypass grafting who do not respond to
B.V. (Biomedical
Division)
334
medical treatment are potential candidates for a repeat operation. Unfortunately, this is technically more difficult, and gives less satisfactory results than the primary operation, while mortality and morbidity rates are higher than for the primary operation [5-71. An attractive alternative approach to the problem is offered by angioplasty of either native vessels, or grafts, or both. In this study we report our experience with the use of angioplasty in patients with prior coronary arterial bypass grafting.
Methods The computerised angioplasty records, clinic notes and angiograms of patients with prior coronary arterial bypass surgery who subsequently underwent percutaneous transluminal coronary angioplasty in the Royal Infirmary of Edinburgh during the period November 1984 to November 1988 were reviewed (during this period 1,450 patients underwent coronary bypass graffting in our centre). It is our policy to repeat coronary angiography in any patient who has had clinically unsatisfactory results from coronary bypass grafting if medical treatment fails to control symptoms. Angioplasty was selected as an alternative to repeat bypass grafting if coronary angiography demonstrated lesions which were thought to be responsible for the symptoms and were considered amenable to angioplasty. Diffuse “atheromatous” disease of a graft more than 1 year old, manifested by multiple shaft irregularities and narrowings, was regarded as a contraindication to angioplasty, as were unprotected stenoses of the left main coronary artery and severe three vessel disease with no grafts remaining patent. Angioplasty was performed by two cardiologists using a femoral approach, a standard long guidewire technique and wire guided balloon catheters. Inflations were continued until angiography (after withdrawal of the balloon) showed a satisfactory result defined as a reduction of more than 50% of the maximum diameter stenosis, or until the patient developed symptoms which necessitated termination of the procedure.
statistics Significance of difference was assessed by Student’s t-test for continuous variables or chi square analysis, after Yates’ correction, for events and patient numbers.
Results Forty-seven patients were analysed; 38 were male. The mean age was 55.9 years (range 24-74 years). At the time of surgery, 6 patients had single-vessel disease, 23 had two-vessel disease, 13 had three-vessel disease, and 5 had more than three vessel disease. Of the patients, 2 had undergone previous coronary artery bypass grafting, 2 had undergone two angioplasties each and a further 3 had undergone one angioplasty each prior to surgery. Grafts were placed on 114 vessels (39 on left anterior descending arteries, 26 on right coronary arteries, 31 on obtuse marginal arteries, 14 on diagonal arteries, and 4 on intermediate arteries). All patients had experienced recurrence of symptoms refractory to maximal medical treatment a mean period of 19.8 months after operation. Angioplasty was performed a mean of 31.3 months after bypass surgery. Sixty-four stenotic sites were identified and, in 60 of them (93.7%) the stenosis was successfully crossed. These included 23 sites within grafts (5 proximal anastomoses, 5 proximal graft sites, 1 mid-graft site, 4 distal graft sites and 8 distal anastomoses) and 37 sites within native vessels (6 in right coronary arteries, 15 in left anterior descending arteries, 3 in diagonal arteries, 11 in circumflex arteries, 1 in an obtuse marginal artery and 1 in a posterolateral artery). Of these native vessels, 23 were supplied by grafts (1 right coronary artery, 14 left anterior descending arteries, 2 diagonal arteries, 1 obtuse marginal artery, 1 posterolateral artery. The lesions could not be crossed in 4 native vessels (2 right coronary arteries, 1 circumflex artery, 1 obtuse marginal artery). All lesions were entered via the native vessel and not via a graft. One patient had a cardiac arrest during the third balloon inflation and was subsequently suc-
335
cessfully resuscitated. Two patients had chest pain which responded to nitrates and opiate. There were no other complications. Initial success, as judged angiographically, was achieved in 42 patients (89.3%) or 58 stenotic sites (90.6%) (Fig. 1). Of the 5 patients with technically unsuccessful angioplasty, or an unsatisfactory result as judged angiographically, 2 had repeat surgery, and no further intervention was possible in the remaining 3. The patients were followed up clinically at 3month intervals. The median duration of follow up was 18 months (range 3-49). During the period of follow-up, 1 patient (who had had an unsuccessful angioplasty) died. Benefit from angioplasty was achieved in 20 patients: 13 were symptomatically much improved (from Canadian Cardiovascular Society Functional Classification Criteria Class III-IV to Class I-II), and 7 patients were still experiencing angina but less severe than prior to their operation (from Class IV to II or III). In 22 patients, however, the benefit from angioplasty had been lost a mean of 4.7 months after the procedure despite a satisfactory initial angiographic result. Sixteen of them had repeat coronary angiography performed a mean of 10.2 months after angioplasty, with the results shown in Table 1. There was no significant difference in the rates of restenosis for grafts and for native vessels, nor was it possible to identify any site with a particular predilection for restenosis.
TABLE
Results of repeat coronary angiography unsatisfactory clinical response.
5 Patients unsuccessful PTCA r42 Patients (58 sites) Anglographic Success
Recurrence of stenosis in a graft Recurrence of stenosis in a native vessel Recurrence of stenosis in a native vessel + a new lesion in a native vessel Good result from previous angioplasty to a graft + new lesions in a graft Good result from previous angioplasty to a native vessel + new lesion in a native vessel New proximal lesion in a graft previously angioplastied Good result from angioplasty to graft; already occluded graft responsible for symptoms
2 6
20 Patients improved
9 Repeat PTCA
2 Repeai Surgery
11 Medical Rx
Fig. 1. Results of angioplasty following coronary arterial bypass grafting. PTCA = percutaneous transluminal coronary angioplasty; Rx = treatment.
2 2 2 1 1
Of the 22 patients with recurrence of symptoms, no further intervention was taken in 11 patients, 2 patients underwent a repeat bypass operation and 9 patients had a repeat angioplasty (Fig. 1). The mean asymptomatic interval between bypass surgery and first angioplasty for the patients with a good outcome after angioplasty was 26.9 months. This differed significantly when compared to the same interval for patients with a poor outcome after angioplasty, which was 12.4 months (P < 0.05). Similarly, the clinical outcome after angioplasty was compared between patients who experienced recurrence of symptoms early
2
Relation between outcome after angioplasty and time of return of symptoms after coronary bypass grafting.
I
I
with an
No. of pts.
Improved after PTCA
1 late death 2 repeat surgery
FOLLOW-UP 18 MONTHS
in 16 patients
Results
TABLE 47 Pattents wth Postoperative Angina
1
Early ( < 6 months) recurrence of symptoms after CABG Late ( > 6 months) recurrence of symptoms after CABG Total X = 6.86 angioplasty;
Not improved after PTCA
3
13
17
9
20
22
after Yates’ correction; CABG = grafting.
P < 0.01. PTCA
=
336 TABLE 3 Characteristics of patients with technically successful angioplasty.
Age Sex Smoking habit
N >5 <5 S
Improved after lWZA (n=20)
Not improved after F’TCA (n = 22)
59.3 f 9.44 15M 5F 4 10 6 0
53.2 k 11.53 18M 4F 3 8 10 1
Total cholesterol
6.57 + 1.50
6.54+
(mmol/l) Triglycerides
2.2 f1.06
2.9 + 1.52
0.05 < P i 0.1 NS NS
1.12
NS 0.05 < P i 0.01
(mmol/l) N = life-long non-smokers; > 5 = ex smokers, stopped more than 5 years prior to F’TCA; < 5 = ex smokers, stopped less than 5 years prior to ETCA; S = smokers; NS = no statistically significant difference; F’TCA = angioplasty.
( < 6 months) after surgery and those with late (> 6 months) recurrence of symptoms. There was a statistically significant difference in outcome after angioplasty, favouring patients with late recurrence of symptoms after surgery (P < 0.01, Table 2). The characteristics of the two groups of patients with different clinical outcome after angioplasty are shown in Table 3. There was no statistically significant difference in sex, smoking habit or total cholesterol values (at the time of angioplasty) between them. Patients with a poor outcome tended to be younger and tended to have higher levels of triglycerides (at the time of angioplasty) but none of these differences reached statistical significance. Unfortunately, information on the lipid status at the time of surgery was not available to us. TABLE 4 Relation of long-term clinical outcome after first graft angioplasty to “age” of graft. No. of pts. Old grafts (‘1
year)
New grafts (< 1 year)
<
<
Clinically improved Clinically not improved or angiographic recurrence Clinically improved Clinically not improved or angiographic recurrence
X = 5.09 (after Yates’ correction);
P i 0.05.
8 1 4 9
Comparison of the clinical or angiographic outcome of angioplasty to “old” (> 1 year) grafts with the outcome of angioplasty to “new” (< 1 year) grafts showed a statistically significant better outcome in old grafts (Table 4). Discussion Aetiology of recurrence of symptoms after coronary arterial bypass surgery
Recurrence of angina after coronary arterial bypass grafting is a complex clinical problem which may be due to several mechanisms. A very rapid recurrence of symptoms (within one month) may be due to technical problems, such as too large an aortotomy [8], or may be a result of incomplete revascularisation, graft failure [9] or total occlusion of grafts secondary to thrombosis [lO,ll]. The latter probability accounts for most of the cases. Angiography may be helpful in detecting technical problems, and sometimes these have a characteristic appearance (such as a constricted distal anastomosis, or shaft narrowing suggestive of thrombus in a valve pocket). Other causes of early recurrence of symptoms include the graft being placed on the wrong vessel, or misdiagnosing oesophageal or skeletal pain as angina. We do not believe these causes applied in the present study. Late recurrence of symptoms (after six months) is more likely to be a result of intimal fibromuscu-
331
lar proliferation in the grafts or progression of atherosclerosis in either the native circulation or in the grafts [9,11]. The rate of progression of atherosclerosis varies between individuals, and probably varies from time to time within the same individual. A number of predictors of the rate of development of atherosclerotic coronary arterial disease have been identified [12-141. Attention has previously been drawn to the need for control of risk factors for atherosclerosis in patients undergoing bypass grafting [15,16]. Initial success and complications
In our series, a satisfactory angiographic result was achieved in 89.3% of patients. Other studies [B-lo, 17-241 have also reported similar high initial success rates (75-95%). The complication rate has been low, again reflecting the experience of others [8-10,17-19,2123]. This rate is considerably lower than the complication rates of a repeat bypass graft, which carries a risk of perioperative myocardial infarction of 2-12% and mortality rates of l-17% [19]. Recurrence of symptoms after percutaneous luminal coronary angioplasty
trans-
We report a rate of 52.3% of recurrence of symptoms after technically successful angioplasty at a median follow up interval of 18 months. Similar rates have been reported by others [B10,17-20,22,25]. Graft restenosis. Some workers [8,9,26,27] have found a higher incidence of restenosis after angioplasty in proximal compared to distal anastomotic sites. We could not confirm this finding, and neither could others [19], but caution is needed in interpreting small numbers. An initially unexpected finding in our present series was a higher long-term success rate after angioplasty of old grafts (in place for more than one year). Several workers [11,19,27] have drawn attention to the dangers of atherothromboembolism after angioplasty of old grafts, which may have a friable and unstable pseudo-intima. We
would agree with these warnings, and advise very careful evaluation before undertaking angioplasty in grafts older than 1 year. It has been suggested that different mechanisms of angioplasty may operate in grafts of different ages [28], with stretching predominating in younger grafts and atherosclerotic plaque “fracture” in older ones. In our own series, despite the higher risk of restenosis in young grafts, repeat angioplasty was often feasible.
Restenosis of native vessels. It should be remembered that patients are likely to be selected for coronary arterial bypass surgery in the first instance because the lesions in their native vessels are relatively unattractive for angioplasty. Ernst et al. [17] found that 46% of patients with prior coronary arterial bypass surgery were free of symptoms 5 years after successful angioplasty, a rate which was significantly lower than for patients undergoing angioplasty as a primary procedure (79%). In their experience, angioplasty of “new” stenoses in the native circulation in patients with prior bypass surgery did not yield as good an outcome as in those who had not undergone previous surgery. They suggested that this can be partially explained by the higher incidence of progression of the disease elsewhere in the native circulation in patients with previous operations. Accelerated progression of atherosclerotic heart disease in patients with prior bypass surgery may be due to inadequate control of risk factors, but bypassing vessels with significant 129-311 or even minimal [32] lesions has been shown to accelerate atherosclerosis in the native circulation, possibly because of rheological factors [29,33]. The symptom-free interval after surgery is likely to reflect the rate of progression of atherosclerotic heart disease. We found that patients with late (> 6 months) recurrence of symptoms after surgery have a lower risk of recurrence of angina after angioplasty, compared to patients with a shorter (less than six months) symptom-free interval. Unfortunately, data are not available for us to attempt correlation between early symptom recurrence and failure to control atheroma risk factors.
338
In
conclusion,
despite the relatively high restenosis rate, angioplasty remains an attractive first-line procedure in patients who develop recurrent angina after coronary bypass grafting. From our experience in the present series we would emphasize three points. First, patients with a rapid progression of disease in their native vessels have a poor outcome. Vigorous efforts should be made to reduce risk factors in such patients both before and after bypass grafting. Second, patients with early stenosis within grafts usually have an excellent early response to angioplasty, but the stenoses tend to recur and repeat angioplasty is often needed. Finally carefully selected patients with a stenosis in an “old” graft may respond well to graft angioplasty. References 1 Kolessov VI. Mammary artery - coronary artery anastomosis as method of treatment for angina pectoris. J Thorac Cardiovasc Surg 1967;54:535-544. 2 Favaloro RG. Saphenous vein auto graft replacement of severe segmental coronary artery occlusion: operative technique. Ann Thorac Surg 1968;5:334-339. 3 Campeau L, Lesperance J, Hermann J, Corbara F, Grondin CM, Bourassa MG. Loss of the improvement of angina between 1 and 7 years after aortocoronary bypass surgery. Circulation 1979;6O(suppl l):l-5. 4 Seides SF, Borer JS, Kent KM, Rosing DR, McIntosh CL, Epstein SE. Long-term anatomic fate of coronary artery bypass grafts and functional status of patients five years after operation. N Engl J Med 1978;298:1213-1217. A, Kemp HG, Jr, Green GE. Reoperation for 5 Cameron coronary artery disease: 10 years of clinical follow-up. Circulation 1988;78(suppl 1); 158-162. 6 Fosler ED, Fisher LD, Kaiser GC, Myers WO. Comparison of operative mortality and morbidity for initial and repeat coronary artery bypass grafting: the Coronary Artery Surgery Study (CASS) registry experience. Ann Thorac Surg 1984;38:563-570. 7 Schaff HV, Orszulak TA, Gersh BJ, et al. The morbidity and mortality of reoperation for coronary artery disease and analysis of late results with use of actuarial estimate of event-free interval. J Thorac Cardiovasc Surg 1983;85:508513. 8 Dorros G, Johnson WD, Tector AJ, Schmahl TM, Kalush SL, Janke L. Percutaneous transluminal coronary angioplasty in patients with prior coronary artery bypass grafting. J Thorac Cardiovasc Surg 1984;87:17-26. P. PTCA: 10 years’ 9 Chokshi SK, Meyers S, Abi-Mansour experience. Prog Cardiovasc Dis 1987;30:147-210. 10 Ford WB, Wholey MH, Zikria EA. et al. Percutaneous transhuninal angioplasty in the management of occlusive
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339 25 El Gamal M. Bonnier H, Michels R, Heijman J, Stassen E. Percutaneous transluminal angioplasty of stenosed aortocoronary bypass grafts. Br Heart J 1984;52:617-620. 26 Douglas JS Jr, Gruentzig AR, King SB et al. Percutaneous transluminal coronary angioplasty in patients with prior coronary bypass surgery. J Am Co11 Cardiol 1983;2:745754. 27 Block PC, Cowley MJ, Kaltenbach M, Kent KM, Simpson J. Percutaneous angioplasty of stenoses of bypass grafts or of bypass graft at anastomotic sites. Am J Cardiol 1984;53:666-668. 28 Wailer BF. Rothbaum DA, Gorfinkel HJ, Ulbright TM, Linnemeier TJ, Berger SM. Morphologic observations after percutaneous transluminal balloon angioplasty of early and late aortocoronary saphenous vein bypass grafts. J Am Co11 Cardiol 1984;4:784-792. 29 Aldridge HE. Trimble AS. Progression of proximal coronary artery lesions to total occlusion after aortocoronary saphenous vein bypass grafting. J Thorac Cardiovasc Surg 1971;62:7-17.
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