Coronary surgery and coronary angioplasty in patients with two-vessel coronary artery disease

Risk stratification after successful coronary revascularization: the lack of a role for routine exercise testing

OBJECTIVE

The objective of this study was to evaluate the American College of Cardiology/American Heart Association (ACC/AHA) guidelines for exercise testing (EXT) after successful coronary revascularization (CR) using the Bypass Angioplasty Revascularization Investigation experience.

BACKGROUND

The ACC/AHA guidelines state that EXT within three years of successful CR is not useful.

METHODS

The 1,678 patients randomized to CR by either angioplasty or bypass surgery were required to take symptom-limited treadmill tests one, three and five years after revascularization.

RESULTS

Patients who took the test at each specified time had a much lower subsequent two-year mortality than those who did not (1.9% vs. 9.4%, 3.5% vs. 12.6% and 3.3% vs. 11.0% at one, three and five years, respectively, after CR [p < 0.0001 for each]). Exercise parameters at the one- and three-year test did not improve a multivariable model of survival after including clinical parameters. Exercising to Bruce stage 3 or generating a Duke score >-6 were independently predictive of two-year survival after the five-year test. ST depression on the one-year test was associated with more revascularizations (relative risk = 1.6; p < 0.001).

CONCLUSIONS

Patients with stable multivessel coronary disease who took a protocol-mandated exercise test at one, three and five years after revascularization were at low risk for mortality in the two years subsequent to each test. Exercise parameters did not improve prediction of mortality in the two years after the one- and three-year tests. The ACC/AHA guidelines on exercise testing after CR (no value for routine testing in stable patients for three years after revascularization) are supported by these results.

Impact of routine angiographic follow-up after angioplasty

BACKGROUND

There is an ongoing controversy as to whether repeat coronary angiography should be routinely performed after successful percutaneous transluminal coronary angioplasty (PTCA).

METHODS

We examined the 10-year outcome in 400 patients who had or had not undergone an angiographic control 6 months after successful PTCA and a subsequent event-free 6-month period. Our comparison was based on data gathered by questionnaire and telephone interview in 315 patients with (group A) and 85 patients without (group B) a routine 6-month angiographic control. Multivariate analysis (Cox model) was performed to identify predictors of adverse events.

RESULTS

During the 10-year follow-up period, 22 (7%) of the 315 patients in group A died, compared with 16 (19%) patients in group B (P= .003). In groups A and B, respectively, acute myocardial infarction occurred in 28 (9%) and 10 (12%) patients (not significant [NS]); coronary artery bypass grafting (CABG) was performed in 42 (13%) and 14 (16%) patients (NS); repeat PTCA was performed in 89 (28%) and 11 (13%) patients (P= .012); and serious adverse events (death, myocardial infarction, CABG) occurred in 76 (24%) and 32 (38%) patients (P= .02). Absence of a 6-month angiographic follow-up was identified as an independent predictor of death associated with a 2.7 times higher mortality rate during the 10-year follow-up period. Previous myocardial infarction increased the risk of death 2.5 times. Any increase of residual diameter stenosis by 10% was combined with a 1.4 times higher mortality rate. The chance of bypass surgery was higher in patients with multivessel disease (2.9 times), in patients with unstable angina (2.1 times), and in case of an increase of residual diameter stenosis by 10% (1.3 times). No predictor for the risk of myocardial infarction was found. Angiographic follow-up increased the likelihood of PTCA 2.5 times.

CONCLUSIONS

A routinely performed angiographic control 6 months after successful PTCA is associated with a significantly higher rate of repeat PTCA but, most important, is correlated with a significantly lower mortality rate during the 10-year follow-up period.

Importance of diabetes mellitus and systemic hypertension rather than completeness of revascularization in determining long-term outcome after coronary balloon angioplasty (the LDCMC registry). Lady Davis Carmel Medical Center

The study examined the 10-year outcome in a cohort of 227 unselected, consecutive patients (age 58+/-10 years) undergoing coronary balloon angioplasty between 1984 and 1986 and followed in a single cardiac center (Lady Davis Carmel Medical Center registry). In particular, we sought to identify the relative importance of the systemic risk factors diabetes and hypertension and the extent of coronary disease as opposed to procedure-related technical variables, the immediate success of the procedure, or completeness of revascularization. By life-table analysis (99% follow-up), 94% of the patients were alive at 5 years, and 77% at 10 years after angioplasty. Ten-year survival was reduced in patients with diabetes mellitus (59% vs 83%, p = 0.0008), in patients with previous myocardial infarction (68% vs 85%, p = 0.01), in patients with ejection fraction <50% (55% vs 82%, p = 0.005), and in patients with 3-vessel disease (58% vs 84% and 86% for 1- and 2-vessel disease, respectively, p = 0.04). Diabetes mellitus was the major independent predictor of poor survival (adjusted odds ratio 3.1, 95% confidence interval 1.55 to 6.19, p = 0.001). Survival at 10 years was identical in 199 patients in whom angioplasty was complete and in 25 in whom the balloon catheter did not cross the lesion, although bypass surgery was more frequent in the latter group (45% vs 21%, p = 0.001). Incomplete revascularization did not predict poor survival (72% vs 79% with complete angioplasty, p = NS). Event-free survival at 10 years for the whole group was 29%, and 49% of patients survived with no event other than a single repeat angioplasty procedure. Multivessel disease, hypertension, and diabetes mellitus were independent predictors of decreased event-free survival, but incomplete revascularization was not. Thus, long-term outcome after coronary balloon angioplasty was related to diabetes mellitus, systemic hypertension, and extent of coronary disease, but not to the immediate success of the procedure or completeness of revascularization.

Value of reversed saphenous vein in minimally invasive direct coronary artery bypass graft procedures

BACKGROUND

Minimally invasive direct coronary artery bypass graft procedures are gaining acceptance for revision as well as primary coronary revascularization. When suitable, the left and right internal mammary arteries are preferred as bypass conduits; in other cases, the greater saphenous vein, used for standard coronary artery bypass graft procedures, may be useful to revascularize coronary artery branches during minimally invasive direct coronary artery bypass graft procedures.

METHODS

We used the greater saphenous vein on three occasions during minimally invasive direct coronary artery bypass graft procedures (1) to revascularize the left anterior descending coronary artery by anastomosis to the left axillary artery in the infraclavicular region, (2) as an extension to the left internal mammary artery to reach the left anterior descending coronary artery, and (3) as a bridge from the splenic artery to bypass the distal right coronary artery.

RESULTS

Postoperatively, all 3 patients had relief from symptoms of coronary artery insufficiency and none has been readmitted to the hospital with symptoms. Angiography or thallium studies were not performed to confirm graft patency because all patients were elderly and the risks of these procedures were considered to outweigh their potential benefit.

CONCLUSIONS

The greater saphenous vein is a potential bypass conduit for use in minimally invasive direct coronary artery bypass graft procedures as well as for coronary artery bypass graft procedures.

Effectiveness of revascularization in the Emory angioplasty versus surgery trial. A randomized comparison of coronary angioplasty with bypass surgery

BACKGROUND

The Emory Angioplasty Versus Surgery Trial (EAST) was designed to determine whether percutaneous transluminal coronary angioplasty (PTCA) is as effective as coronary artery bypass graft surgery (CABG) in restoring arterial perfusion capacity in eligible patients with multivessel disease.

METHODS AND RESULTS

Of 392 patients in EAST, 198 were randomized to PTCA and 194 to CABG. Index lesions (2.7 +/- 1.0 per patient) were those with > or = 50% stenosis judged treatable by both angioplasty and surgery. Coronary segments jeopardized by these index lesions were designated as index segments (4.4 +/- 1.4 per patient). Percent stenosis was measured by quantitative angiography at the point of greatest obstruction in the main perfusion path of each index segment. The EAST primary arteriographic end point was the percent of a patient's index segments with < 50% stenosis in the main perfusion pathways at 1 and 3 years. At baseline, the percent of index segments for which revascularization was attempted was 85% for PTCA and 98% for CABG (P < .0001). At 1 year, PTCA patients had a smaller percentage of successfully revascularized index segments than CABG patients (59% versus 88%, P < .001). At 3 years, the findings were similar but less striking (70% versus 87%, P < .001). When only "high-priority" index segments (2.1 +/- 1.6 per patient) were considered, baseline attempts were comparable (96% versus 99%, P = NS); despite this, CABG remained more successful at 1 (64% versus 93%, P < .001) and 3 (76% versus 89%, P < .01) years. However, the mean percent of index segments free of severe stenosis (> or = 70%) did not differ between PTCA and CABG patients at 3 years (93% versus 95%, P = NS). Furthermore, the frequency of patients with all index segments free of severe stenosis did not differ between the two groups at 1 (76% versus 83%, P = NS) or 3 (82% for both PTCA and CABG) years.

CONCLUSIONS

In patients with multivessel disease, index segment revascularization was more complete with CABG than PTCA at both 1 and 3 years. However, when the physiological priority of the target lesion and the measured severity of the residual stenosis are taken into account, the advantage of CABG becomes less significant or nonsignificant. This may, in part, explain why these two strategies did not differ in terms of the EAST primary clinical end points over 3 years.

The invasive management of angina: issues for consumers and commissioners

OBJECTIVE

To review, from the purchaser's perspective, the current state of knowledge of techniques for investigation and treating coronary artery disease. The study was based on evidence from past and continuing randomised controlled trials (RCTs). CRITERIA FOR INCLUSION OF REPORTS: Articles listed on Medline (1990-3) with the keywords coronary disease, angina, and unstable angina (combined with surgery, economics, therapy, or drug therapy) and percutaneous transluminal coronary angioplasty (PTCA) and coronary artery bypass grafting (CABG) were included. Articles published before 1990 were obtained from two comprehensive literature reviews published by the Rand organisation in 1991 and from the papers obtained using the Medline search. A hand search of relevant journals published between July 1993 and June 1994 was also undertaken. Results from more recently published RCTs are included.

RESULTS

CABG provides improved angina relief compared with drug treatment and may prolong life in patients with more severe illness. PTCA is also better than drug treatment, but less so than CABG, and its cost advantages over CABG decrease with time. Repeat intervention for return of symptoms is more frequently required after PTCA, but increasing numbers of patients are also undergoing second and third repeat CABG for graft occlusion in the years after the original operation. Newer PTCA techniques are not, as yet, fully evaluated. One technique, atherectomy, has been shown to be no more effective, and more expensive, than conventional balloon angioplasty. In the short term intracoronary stents reduce the problems associated with vessel occlusion after PTCA and therefore reduce the need for further intervention. PTCA should not be performed without ready access to cardiothoracic support. There is an increasing trend towards the development of coronary catheterisation units at peripheral sites. This may lead to increasing, inappropriate use of this investigation in suboptimal circumstances.

CONCLUSIONS

Ischaemic heart disease is an important cause of morbidity and mortality and invasive management techniques are developing rapidly; some service expansion is occurring without trial evidence. More research is required to determine the optimum balance of PTCA, CABG, and angiography and population requirements for these procedures. In the meantime, in the absence of firm long term evidence of the superior cost effectiveness of PTCA compared with CABG, the rapid expansion of this procedure should be limited. Patients should be fully informed of the benefits and disadvantages of CABG and PTCA, where either procedure is indicated, to enable them to make fully informed choices.

Percutaneous transluminal coronary angioplasty as a first revascularization procedure in single-, double- and triple-vessel coronary artery disease

OBJECTIVES

We sought to compare in-hospital and long-term outcome after angioplasty in patients with single-, double- and triple-vessel disease.

BACKGROUND

Coronary angioplasty is increasingly used in patients with multivessel disease.

METHODS

The source of data was the clinical data base at Emory University. Patients who had previous coronary revascularization or who underwent angioplasty in the setting of acute myocardial infarction were excluded.

RESULTS

Of 10,783 patients, 71% had one-vessel, 24% two-vessel and 5% three-vessel disease. Age, male gender, diabetes, hypertension, history of previous myocardial infarction, Canadian Cardiovascular Society class III or IV angina and congestive failure all increased with severity of disease. Complete revascularization was achieved in most patients with one-vessel disease, in a minority with two-vessel disease and rarely in those with three-vessel disease. Emergency coronary bypass surgery increased from 1.7% with one-vessel disease to 3.2% with three-vessel disease. Q wave myocardial infarctions could not be shown to vary significantly with severity of disease. The mortality rate increased from 0.2% with one-vessel disease to 1.2% with three-vessel disease. The number of vessels diseased was a multivariate correlate of in-hospital and long-term mortality. The 1-, 5- and 10-year survival was 0.99, 0.93 and 0.86 for one-vessel disease and 0.97, 0.89 and 0.76 for two-vessel disease, respectively. The 1-, 5- and 9-year survival was 0.95, 0.85 and 0.70 in three-vessel disease, respectively. Freedom from myocardial infarction, coronary bypass surgery and repeat angioplasty was also lower with more severe disease.

CONCLUSIONS

Patients have increasing in-hospital and long-term mortality as the severity of disease increases. There is also an increased incidence of myocardial infarction and revascularization procedures with more severe disease.

A randomized study of coronary angioplasty compared with bypass surgery in patients with symptomatic multivessel coronary disease. German Angioplasty Bypass Surgery Investigation (GABI)

BACKGROUND

The standard treatment for patients with symptomatic multivessel coronary artery disease is coronary-artery bypass grafting (CABG). Percutaneous transluminal coronary angioplasty (PTCA) is widely used as an alternative approach to revascularization, but a systematic comparison of the two procedures is needed. We compared the outcomes in patients one year after complete revascularization with CABG or PTCA.

METHODS

A total of 8981 patients with multivessel coronary disease were screened at eight clinical sites, and 359 patients were randomly assigned to undergo CABG (177 patients) or PTCA (182 patients). Enrollment required that complete revascularization of at least two major vessels supplying different myocardial regions be deemed clinically necessary and technically feasible.

RESULTS

Among the patients in the CABG group, an average of 2.2 +/- 0.6 vessels were grafted, and among those in the PTCA group, 1.9 +/- 0.5 vessels were dilated. After CABG, hospitalization was longer (median, 19, as compared with 5 days for PTCA), and Q-wave myocardial infarction in relation to the procedure was more frequent (8.1 percent, as compared with 2.3 percent after PTCA; P = 0.022), whereas in-hospital mortality did not differ significantly between the two groups (2.5 percent in the CABG group and 1.1 percent in the PTCA group). At discharge 93 percent of the patients in the CABG group were free of angina, as compared with 82 percent of those in the PTCA group (P = 0.005). During the first year of follow-up, further interventions were necessary in 44 percent of the patients in the PTCA group (repeated PTCA in 23 percent, CABG in 18 percent, and both in 3 percent) but in only 6 percent of the patients in the CABG group (repeated CABG in 1 percent and PTCA in 5 percent; P < 0.001). Seventy-four percent of the patients in the CABG group and 71 percent of those in the PTCA group were free of angina one year after treatment. Exercise capacity improved similarly in both groups. However, 22 percent of the CABG group, as compared with only 12 percent of the PTCA group, did not require antianginal medication (P = 0.041).

CONCLUSIONS

In selected patients with multivessel coronary disease, PTCA and CABG as initial treatments resulted in equivalent improvement in angina after one year. However, in order to achieve similar clinical outcomes, the patients treated with PTCA were more likely to require further interventions and antianginal drugs, whereas the patients treated with CABG were more likely to sustain an acute myocardial infarction at the time of the procedure.

A randomized trial comparing coronary angioplasty with coronary bypass surgery. Emory Angioplasty versus Surgery Trial (EAST)

BACKGROUND

The clinical benefit of percutaneous transluminal coronary angioplasty (PTCA) as compared with coronary-artery bypass grafting (CABG) for patients with multivessel coronary artery disease has not been established. To determine the outcomes of these treatments in patients referred for the first time for coronary revascularization, we conducted a three-year prospective, randomized trial comparing the two procedures.

METHODS

Revascularization was performed by accepted methods. Follow-up clinical information was collected every six months, and coronary arteriography and thallium stress scanning were performed at one and three years. The primary end point was a composite of death, Q-wave myocardial infarction, and a large ischemic defect identified on thallium scanning at three years. Secondary end points included clinical and angiographic status and the need for additional revascularization procedures. Data were analyzed according to the intention-to-treat principle.

RESULTS

Of the 5118 patients screened for the trial, 842 (16.5 percent) were eligible for enrollment, and 392 (7.7 percent) agreed to participate. A total of 194 patients were randomly assigned to the CABG group, and 198 to the PTCA group. The primary end point occurred in 27.3 percent of the CABG group and 28.8 percent of the PTCA group (P = 0.81). Death occurred in 6.2 percent of the CABG group and 7.1 percent of the PTCA group (P = 0.73 by log-rank test). At three years, the proportions of patients in the CABG group who required repeated bypass surgery (1 percent) or angioplasty (13 percent) were significantly lower than the proportions in the PTCA group (22 and 41 percent, respectively; P < 0.001). Angiographic studies at three years showed a greater degree of revascularization in the CABG group. Angina was more frequent in the PTCA group (20 percent) than in the CABG group (12 percent).

CONCLUSIONS

We found that CABG and PTCA did not differ significantly with respect to the occurrence of the composite primary end point. Consequently, the selection of one procedure over the other should be guided by patients' preferences regarding the quality of life and the possible need for subsequent procedures.

Continuing evolution of therapy for coronary artery disease. Initial results from the era of coronary angioplasty

BACKGROUND

Survival after coronary artery bypass graft surgery (CABG) and medical therapy in patients with coronary artery disease (CAD) has been studied in both randomized trials and observational treatment comparisons. Over the past decade, the use of coronary angioplasty (PTCA) has increased dramatically, without guidance from either randomized trials or prospective observational comparisons. The purpose of this study was to describe the survival experience of a large prospective cohort of CAD patients treated with medicine, PTCA, or CABG.

METHODS AND RESULTS

The study was designed as a prospective nonrandomized treatment comparison in the setting of an academic medical center (tertiary care). Subjects were 9263 patients with symptomatic CAD referred for cardiac catheterization (1984 through 1990). Patients with prior PTCA or CABG, valvular or congenital disease, nonischemic cardiomyopathy, or significant (> or = 75%) left main disease were excluded. Baseline clinical, laboratory, and catheterization data were collected prospectively in the Duke Cardiovascular Disease Databank. All patients were contacted at 6 months, 1 year, and annually thereafter (follow-up 97% complete). Cardiovascular death was the primary end point. Of this cohort, 2788 patients were treated with PTCA (2626 within 60 days) and 3422 with CABG (3080 within 60 days). Repeat or crossover revascularization procedures were counted as part of the initial treatment strategy. Kaplan-Meier survival curves (both unadjusted and adjusted for all known imbalances in baseline prognostic factors) were used to examine absolute survival differences, and treatment pair hazard ratios from the Cox model were used to summarize average relative survival benefits. For the latter, a 13-level CAD prognostic index was used to examine the relation between survival and revascularization as a function of CAD severity. The effects of revascularization on survival depended on the extent of CAD. For the least severe forms of CAD (ie, one-vessel disease), there were no survival advantages out to 5 years for revascularization over medical therapy. For intermediate levels of CAD (ie, two-vessel disease), revascularization was associated with higher survival rates than medical therapy. For less severe forms of two-vessel disease, PTCA had a small advantage over CABG, whereas for the most severe form of two-vessel disease (with a critical lesion of the proximal left anterior descending artery), CABG was superior. For the most severe forms of CAD (ie, three-vessel disease), CABG provided a consistent survival advantage over medicine. PTCA appeared prognostically equivalent to medicine in these patients, but the number of PTCA patients in this subgroup was low.

CONCLUSIONS

In this first large-scale, prospective observational treatment comparison of PTCA, CABG, and medicine, we confirmed the previously reported survival advantages for CABG over medical therapy for three-vessel disease and severe two-vessel disease. For less severe CAD, the primary treatment choices are between medicine and PTCA. In these patients, there is a trend for a relative survival advantage with PTCA, although absolute survival differences were modest. In this setting, treatment decisions should be based not only on survival differences but also on symptom relief, quality of life outcomes, and patient preferences.

Benefit of adding low molecular weight heparin to the conventional treatment of stable angina pectoris. A double-blind, randomized, placebo-controlled trial

BACKGROUND

Patients with chronic coronary artery disease exhibit a dysfunctioning endothelium, which may be responsible for exercise-induced platelet activation and expression of a procoagulant moiety. In this study, we evaluated the therapeutic efficacy of a low molecular weight heparin (Parnaparin) in patients with stable angina pectoris.

METHODS AND RESULTS

According to a double-blind, randomized, placebo-controlled trial, 29 patients with stable exercise-induced angina pectoris and angiographically proven coronary artery disease received a single daily subcutaneous injection of Parnaparin or placebo on top of aspirin and conventional antianginal medication over 3 months. Patients randomized to Parnaparin showed a significant decrease in the fibrinogen level (P = .035) and an improvement in both the time to 1-mm ST segment depression (P = .008) and the peak ST segment depression (P = .015). The Canadian Cardiovascular Society class for angina pectoris was also improved by Parnaparin (P = .016). Parnaparin did not affect ADP and collagen-induced platelet aggregation, whereas thrombin-induced aggregation was reduced (P = .0001). The bleeding time was slightly prolonged, but this was not associated with any significant bleeding.

CONCLUSIONS

Patients with stable angina pectoris may be treated with Parnaparin in addition to aspirin and conventional antianginal medication. Side effects are negligible, and compliance is excellent.