Initial and late results of coronary angioplasty for early postinfarction unstable angina

Coronary Angioplasty in Patients with Unstable Angina, with Special Reference to Preceding Treatment with Antithrombin III and Heparin

Seventy-nine patients undergoing percutane ous transluminal coronary angioplasty (PTCA) for unsta ble angina were analyzed with respect to preceding an tithrombin treatment; group I comprised patients (n = 26) without antecedent antithrombin therapy; group II, pa tients (n = 30) with heparin infusion for ≥24 h, and group III patients (n = 23) with ongoing heparin infusion and given antithrombin III concentrate immediately before the procedure because of plasma antithrombin III <85%. Immediate results were 89% (70 of 79) angiographic suc cess, five (6%) subacute occlusions (two subsequent non-Q wave infarctions), no emergency coronary artery bypass grafting (CABG), and no immediate mortality. There were no differences between the groups. From dis charge to 4 months, one patient died, one had a nonfatal infarction, and 24 (30%) had repeated PTCA or CABG. The cumulative 4-month event rate was 11 of 26 (42%) in group I, 10 of 30 (33%) in group II, and 7 of 23 (30%) in group III (NS). During PTCA, heparin bolus administra tion was guided by activated clotting time (ACT), aiming at>300 s. Baseline ACT was significantly less in patients not treated with heparin (129 ± 34 s in group I vs. 179 ± 38 and 162 ± 29 s in groups II and III, respectively; p < 0.05), but during the procedure, patients from all groups required the same amount of heparin (13,900 ± 4,800, 13,000 ± 6,800, and 13,000 ± 5,700 IU, respectively; NS) to reach similar maximum ACT levels (334 ± 36, 312 ± 32, and 319 ± 44 s, respectively; NS). Patients receiving warfarin ( n = 8) responded with a higher ACT (456 ± 110 s; p < 0.05) on lower doses of heparin (10,000 ± 3,800 IU). In conclusion, patients with unstable angina receiv ing individualized antithrombotic therapy can be success fully treated with PTCA, with an acute complication rate and long-term results comparable with those expected in patients undergoing elective procedures. The value of an tithrombin III substitution must be evaluated in random ized trials. Preprocedural heparin infusion does not re duce the need of extra heparin during the procedure. Key Words: Antithrombin III—Heparin—PTCA (percutane ous transluminal coronary angioplasty)—Unstable angina pectoris.

Unstable Angina Pectoris: An Interventional Approach to Management

The therapy of unstable angina has changed consider ably in the last 15 years. An improved understanding of the pathophysiology has led to many of the changes. Thrombus, platelet activation, progression of athero sclerosis, and coronary vasospasm all appear to have a role. Initial management in unstable angina should begin with aggressive medical therapy with nitrates, calcium antagonists, beta blockers, and aspirin. In patients who are refractory to aggressive medical management, early cardiac catheterization and coronary arteriography is in dicated. The literature appears to confirm that patients with unstable angina who are stabilized with aggressive medical therapy fare as well as those treated with emer gency bypass surgery. Percutaneous transluminal coro nary angioplasty (PTCA) is the treatment of choice in medically refractory unstable angina patients with single-vessel coronary disease.

New approaches include culprit lesion angioplasty, thrombolytic therapy, coronary sinus retroperfusion, and new catheter-based revascularization methods such as intracoronary stents, laser methods and atherectomy. Culprit lesion angioplasty involves angioplasty of only the angina-producing artery in patients with multivessel coronary disease. Early data suggest that this may be an effective short-term alternative to multivessel PTCA or bypass surgery. Recent data also suggest a beneficial role for thrombolytic therapy and synchronized coronary si nus retroperfusion with arterial blood in patients with unstable angina. New catheter-based approaches are in the early stages of development, and their eventual role in the treatment of coronary artery disease and unstable angina remains to be elucidated.

Management of high-risk subsets in unstable angina

This article focuses on the optimal treatment of postinfarction, refractory, or recurrent angina based on the results of recent clinical trials. Many of our recommendations hold true for the general management of unstable angina, but special considerations for the high-risk subsets are emphasized. Specifically, we discuss acute medical management and suggest that an early aggressive strategy that leads to early coronary angiography with the goal of revascularization when feasible best serves this subset. A special emphasis on the emerging role of glycoprotein IIb-IIIa antagonists is made because the important role of platelets in coronary thrombosis has dominated recent views on the pathophysiology of unstable angina.

A patent infarct-related artery is associated with reduced long-term mortality after percutaneous transluminal coronary angioplasty for postinfarction ischemia and an ejection fraction <50%

BACKGROUND

Prognosis after myocardial infarction (MI) is influenced by the presence of post-MI ischemia and possibly the patency of the infarct-related artery. The purpose of this study was to compare long-term outcome (reinfarction and death) in patients with open versus closed coronary arteries after percutaneous transluminal coronary angioplasty performed for MI complicated by persistent ischemia.

METHODS AND RESULTS

Between 1981 and 1989, 505 patients underwent percutaneous transluminal coronary angioplasty for post-MI ischemia at the Deaconess Hospital. Long-term incidence (mean follow-up, 34 months) of death, nonfatal reinfarction, repeated coronary angioplasty, and coronary bypass surgery was determined for 479 patients and then compared on the basis of the status of the artery, open versus closed, at the end of angioplasty. The 5-year Kaplan-Meier actuarial mortality rate was 4.9% for 456 patients with open infarct-related arteries and 19.4% for 23 patients with closed infarct-related arteries (P=.0008). Multivariate Cox proportional hazards analyses controlling for age, sex, number of diseased vessels, type and location of MI, and year of coronary angioplasty revealed a hazard ratio for death for closed compared with open arteries of 6.1 (95% CI, 1.8 to 20.0). Among patients with ejection fractions <50%, a closed artery was associated with a higher mortality (p=.0014) compared with patients with open arteries. The status of the artery was not associated with a difference in mortality in patients with ejection fractions > or = 50%.

CONCLUSIONS

As open artery after coronary angioplasty for post-MI ischemia is associated with significantly lower long-term mortality, particularly in patients with ejection fractions <50%.

Significance of location (anterior versus inferior) and type (Q-wave versus non-Q-wave) of acute myocardial infarction in patients undergoing percutaneous transluminal coronary angioplasty for postinfarction ischemia

Predictors of increased risk for recurrent cardiac events and death after acute myocardial infarction include postinfarction myocardial ischemia, anterior location of the infarct, and non-Q-wave versus Q-wave infarction. Although coronary angioplasty is performed in patients with postinfarction ischemia to alleviate symptoms, the outcome according to location and type of infarction and the effect on prevention of subsequent myocardial infarction and death are not known. To determine if location and type of myocardial infarction provide prognostic information in patients with postinfarction ischemia, we analyzed morbidity and mortality during and after coronary angioplasty according to the location (anterior vs inferior) and type (Q-wave vs non-Q-wave) of myocardial infarction in 505 consecutive patients. The incidence of recurrent angina, repeat coronary angioplasty, coronary bypass surgery, reinfarction, and death during long-term follow-up after hospital discharge (mean 34 +/- 19 months) for the 440 patients with an initial successful angioplasty was also compared. During the procedure, there was no difference in the primary success rate or mortality among the different groups; however, more patients with anterior non-Q-wave myocardial infarction underwent emergent bypass grafting after unsuccessful coronary angioplasty (p = 0.001). Multivariate Cox proportional-hazards analyses controlling for age, gender, number of diseased vessels, location, type of infarction, and year of coronary angioplasty revealed that more patients with anterior infarction had > or = 1 cardiac event (repeat angioplasty, coronary artery bypass grafting, reinfarction, or death) than did those with inferior infarction (RR 1.80, 95% confidence interval [Ci] 1.22 to 2.65, p = 0.003).(ABSTRACT TRUNCATED AT 250 WORDS)

Thrombolytic retreatment with tissue plasminogen activator for threatened reinfarction and thrombotic coronary reocclusion

Following successful coronary arterial thrombolysis, thrombogenic substrate persists, increasing the risk of recurrent thrombosis, reocclusion, and reinfarction. The preferred treatment in this setting has not been established. Although many patients receive mechanical revascularization, it is conceivable that repeat thrombolysis, primarily with tissue plasminogen activator, represents the most readily available and effective alternative.

Similar results of percutaneous transluminal coronary angioplasty for women and men with postmyocardial infarction ischemia

OBJECTIVES

The purpose of this study was to determine whether there are gender differences in the outcome of percutaneous transluminal coronary angioplasty performed for postmyocardial infarction ischemia.

BACKGROUND

Although women have a higher mortality rate after myocardial infarction than that of men, they are less frequently referred for coronary angioplasty (and coronary artery bypass graft surgery) than are men, possibly because of expectations of a worse procedural outcome.

METHODS

We analyzed the morbidity and mortality at coronary angioplasty and during a mean follow-up period of 34.4 months for women and 34.2 months for men in 505 consecutive patients (164 women and 341 men) with postmyocardial infarction ischemia between 1981 and 1989.

RESULTS

Compared with men, women had similar procedural success rates (89.6% and 91.2%, respectively), need for coronary artery bypass surgery (3.7% and 2.6%) and mortality rates at coronary angioplasty (0.6% and 0.9%). During the follow-up period, there were no significant gender differences in the requirement for coronary artery bypass surgery (3.6% and 4%), repeat angioplasty (18.7% and 17.3%), reinfarction (5.8% and 6%) and death (3.6% and 3.7%) or the combined end points of all four events (26.6% and 26.6%). Women had significantly more recurrent angina than did men (54% vs. 42.5%, p < 0.01), even though the extent of coronary artery disease and frequency of incomplete revascularization were similar in men and women.

CONCLUSIONS

The procedural outcome of coronary angioplasty for postmyocardial infarction ischemia is similar in women and men. Long-term follow-up is also similar except that women experience an increased incidence of recurrent angina, an outcome also reported after bypass surgery. Therefore, concerns over the safety of coronary angioplasty in women should not adversely influence decisions concerning referral of women for coronary angioplasty after myocardial infarction complicated by ischemia.

Argentine randomized trial of percutaneous transluminal coronary angioplasty versus coronary artery bypass surgery in multivessel disease (ERACI): in-hospital results and 1-year follow-up. ERACI Group

OBJECTIVES

This study was designed to compare freedom from combined cardiac events (death, angina, myocardial infarction) at 1-, 3- and 5-year follow-up in patients with multivessel disease randomized to either percutaneous transluminal coronary angioplasty or coronary artery bypass graft surgery.

BACKGROUND

Percutaneous transluminal coronary angioplasty has been an effective approach in patients with coronary artery disease, but its role in patients with multivessel coronary artery disease is still controversial.

METHODS

One-hundred twenty-seven patients with multivessel disease and lesions suitable for either form of therapy were randomized to either coronary artery bypass grafting (n = 64) or coronary angioplasty (n = 63). In this study we report the immediate results and freedom from combined cardiac events at 1-year follow-up.

RESULTS

Demographic, clinical and angiographic characteristics were similar in both groups. There were no differences in in-hospital deaths, frequency of periprocedure myocardial infarction or need for emergency revascularization procedures between the two groups. At 1-year follow-up, there were no differences in mortality or in the incidence of myocardial infarction between the groups. However, patients treated with coronary artery bypass grafting were more frequently free of angina, reinterventions and combined cardiac events than were patients treated with coronary angioplasty (83.5% vs. 63.7%, p < 0.005). In-hospital cost and cumulative cost at 1-year follow-up were greater for the coronary artery bypass grafting than for the coronary angioplasty group.

CONCLUSIONS

No significant differences were found in major in-hospital complications between patients treated with coronary artery bypass grafting or coronary angioplasty. Although at 1-year follow-up there were no differences in survival and freedom from myocardial infarction, patients in the coronary artery bypass grafting group were more frequently free from angina, reinterventions and combined events than were patients in the coronary angioplasty group.

Salvage angioplasty: an alternative to high risk surgery for unstable angina?

This prospective, Human Subjects Committee and Ethics Committee approved investigation was performed to determine if coronary angioplasty (PTCA) might be a reasonable alternative revascularization method for unstable angina patients thought to be at high risk for operative (CABG) mortality. Between March 1990 and October 1991, thirty-four consecutive patients with medically refractory rest angina were deamed to have high risk of surgical mortality and underwent PTCA without surgical backup. Predicted operative mortality was calculated for each patient based upon the VA Surgical Risk Assessment model. Angioplasty of 52 vessels was attempted. Reduction in lumenal narrowing to < 50% and improved angiographic flow was obtained in 47 vessels. There were four complicating infarctions. One death occurred in the lab, and three patients with unsuccessful angioplasty died within 30 days of pump failure. Relief of angina occurred in 30/34. Thirty patients were discharged home. In follow-up from 1 to 12 months, there have been 2 late sudden deaths at 4 months and 9 months, 1 death from lung cancer; 4 patients have stable exertional angina; 2 are awaiting heart transplant but are pain free, and one patient who had PTCA during cardiogenic shock from acute myocardial infarction had elective coronary artery bypass surgery. There have been no late myocardial infarctions. The observed angioplasty 30-day mortality of 11.8% (95% confidence limit 1% to 22.6%) compares favorably with the predicted operative mortality of 23.8% for this group. This prospective but non-randomized series supports the concept that balloon angioplasty may be a reasonable alternative to surgical intervention in some patients with unstable angina and high risk for surgery. A prospective randomized trial is warranted.

Recurrent myocardial ischemia following thrombolytic therapy: guidelines for practicing clinicians

The natural history of patients with acute myocardial infarction treated with thrombolytic therapy includes two distinct phases: the initial or acute phase is characterized pathologically by atheromatous plaque rupture and thrombotic coronary arterial occlusion, and clinically by the abrupt onset of symptoms. Prompt restoration of coronary blood flow and myocardial reperfusion during this phase, achieved in a majority of patients given thrombolytic therapy, limits myocardial necrosis, preserves ventricular function, and lowers mortality. Although the thrombus can be pharmacologically removed, an unstable anatomic substrate persists. Therefore following thrombolytic therapy, a subacute phase occurs, during which patients are at risk for recurrent ischemic events. More than a theoretical concept, experience has shown that recurrent ischemia and reinfarction develop in 20% to 30% and 5% of patients, respectively. Morbidity and mortality are elevated considerably in these patients, dictating an aggressive diagnostic and treatment approach.

Percutaneous transluminal coronary angioplasty for unstable angina

Coronary angioplasty is an effective treatment for patients with angina at rest, either refractory or initially stabilized but returning despite pharmacologic treatment, and with early postinfarction angina. The procedure has a high initial success rate, but there is an increased risk of major complications resulting from a higher incidence of acute closure, which may be related to preexisting thrombus. Resolution of this problem may be achieved by the use of more potent antiplatelet treatment, pretreatment with thrombolytic agents, or treatment that can be applied locally (e.g., laser energy, atherectomy) at the site of the unstable plaque. Results in this study have been obtained from selected groups of patients: those with predominantly single-vessel disease and well-preserved left ventricular function. It remains to be determined whether the same benefits can be achieved in patients with multivessel disease or in those who have severely reduced left ventricular function.

Coronary angioplasty for medically refractory unstable angina within 30 days of acute myocardial infarction

Percutaneous transluminal coronary angioplasty (PTCA) has been used with good results in selected patients with unstable angina. The population with recent (less than or equal to 30 days) infarction and unstable angina is a subject of controversy. This report reviews the results of angioplasty of 84 vessels in 66 patients with medically refractory unstable angina who had documented myocardial infarction within 30 days of the procedure. Of these 66 patients, 54 had rest angina. Of the 66 patients with angioplasties, 58 patients (88%) had successful procedures. Two patients had technically unsuccessful results in the only vessel attempted; one went to elective surgery and recovered uneventfully and the other patient was in cardiogenic shock at the time of the procedure and died 12 hours later. There were three acute occlusions of infarct-related arteries that were managed medically. There were two (3%) emergency coronary artery bypass graft (CABG) procedures. There were two (3%) deaths during the index hospitalization. Of the 58 of 66 patients with technically successful angioplasty, all 58 had no more rest angina, and 46 had a satisfactory predischarge exercise test. All 46 were without angina at exercise. In follow-up ranging from 4 months to 36 months (14 months mean), there have been six cases of restenosis with recurrence of angina treated successfully with repeat angioplasty. There have been five late bypass surgeries. There have been three late deaths. These data, generated by a single operator in a Veterans Administration (VA) center, support the use of angioplasty in patients with unstable angina and recent myocardial infarction. The data suggest that a VA prospective randomized trial of PTCA versus CABG for post-infarction angina may be feasible.

Percutaneous transluminal coronary angioplasty for rest angina pectoris requiring intravenous nitroglycerin and intraaortic balloon counterpulsation

In selected patients with medically refractory rest angina, percutaneous transluminal coronary angioplasty (PTCA) might be a reasonable alternative to coronary artery bypass graft surgery. Between January 1987 and November 1989, 1 operator at a Veterans Administration center performed PTCA on 73 vessels in 56 patients with rest angina of sufficient severity to require intravenous nitroglycerin in all 56 and intraaortic balloon counter-pulsation (IABP) in 18. Of the 56 patients, 17 (30%) had 1-vessel disease, 14 (25%) had 2-vessel disease and 25 (45%) had 3-vessel disease; 14 (25%) had greater than or equal to 1 prior bypass surgery, 35 (62.5%) were within 30 days of an acute infarction, 12 (21%) had left ventricular ejection fraction less than 0.50 and 7 (12.5%) were greater than 70 years of age. PTCA was successful in 61 (84%) vessels and 47 (84%) patients (greater than or equal to 1 vessel plus relief of angina). During index hospitalization, there were 2 deaths (3.6%), 4 myocardial infarctions (7.2%), 4 emergent bypass surgeries (7.2%) and 1 semiemergent bypass (1.8%) for technically unsuccessful PTCA. In follow-up from 3 to 36 months, there has been 1 additional myocardial infarction (1.8%), 1 late death (1.8%), 2 repeat PTCAs (3.6%), 6 crossovers to bypass (10.7%) and 38 patients (68%) have remained cardiac-event free. Although this angioplasty cohort is small and selected, these data raise the possibility that a prospective randomized comparison of PTCA versus bypass surgery might be feasible and appropriate in a subset of unstable angina patients who require intravenous nitroglycerin or IABP.

Unstable angina

Unstable angina can manifest as an array of symptom complexes. In some patients, medical therapy will stabilize the episodes of angina, and only predismissal exercise testing or angiography (or both) will be necessary. At the other end of the spectrum are patients with rest angina or multiple episodes of silent ischemia who are refractory to medical therapy and experience undetected microinfarction. Most of these patients require immediate catheterization and subsequent intervention with intra-aortic balloon pulsation, percutaneous transluminal coronary angioplasty, or coronary artery bypass grafting. An entire spectrum of manifestations exists between these two extremes. One challenge during the 1990s will be better stratification of patients with unstable angina so that safe, efficient, cost-effective treatment strategies can be appropriately applied to all patients.

Use of percutaneous transluminal coronary angioplasty and bypass surgery despite improved medical therapy for unstable angina pectoris

To evaluate current strategies for the management of unstable angina, 104 consecutive patients admitted to the coronary care unit with unstable angina during a 6-month period were followed prospectively. Although 58 patients had symptomatic relief with the initiation of intensive medical therapy, 46 (44%) continued to have episodes of angina despite maximal tolerated triple-drug antianginal therapy as well as aspirin or heparin, or both. In-hospital mortality for the 104 patients was 4%. The incidence of myocardial infarction was 8%, and differed (p less than 0.01) for the medically responsive group (3%) vs the medically refractory group (13%). Based on clinical status and coronary anatomy, patients were referred for either bypass surgery (46%), coronary angioplasty (41%) or continued medical therapy (13%). Choice of therapy varied according to the extent of coronary disease, with coronary angioplasty attempted in 72% of patients with 1-vessel disease, 44% of patients with 2-vessel disease and 7% of patients with 3-vessel disease. Angioplasty was performed with an initial success rate of 88%, and compared favorably with bypass surgery in terms of in-hospital mortality (0 vs 11%), late mortality (2.8 vs 7.7%), freedom from angina (62 vs 69%) and subsequent employment (44 vs 27%) at 18 months follow-up. The favorable results of angioplasty in this prospective observational study suggest that additional randomized trials should be conducted in this important patient group.

Death after acute myocardial infarction: interrelation between left ventricular dysfunction, arrhythmias and ischemia

Patients who survive an acute myocardial infarction face an increased risk of sudden death for approximately 6 months after hospital discharge; their prognosis is determined by the severity of their coronary arteriosclerosis and the degree of left ventricular dysfunction. Frequent ventricular premature complexes and evidence of ischemia either spontaneously or on treadmill are also markers for early morbidity and mortality in patients who are discharged from the hospital after acute myocardial infarction. The degree of left ventricular dysfunction is the strongest predictor of mortality; patients who have both left ventricular dysfunction, frequent premature ventricular beats and evidence of ischemia are at the highest risk of mortality after hospital discharge. It appears likely that all 3 of these risk factors interact and that therapy to reduce morbidity and mortality after myocardial infarction should aim at the amelioration of each of these risk factors. A model for the interaction of these risk factors is proposed and an approach to treatment for patients at high risk of mortality after hospital discharge after myocardial infarction is suggested.