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

Predictive validity of the Braunwald classification of unstable angina for angiographic findings, short-term prognoses, and treatment selection

The authors tested the Braunwald classification for its predictive validity for underlying coronary conditions, clinical courses, and responses to treatment. A reliable definition and classification of unstable angina is needed to help physicians make correct diagnoses of patients' conditions and to appraise findings from clinical trials critically. Many clinical trials have been conducted, but it is difficult to compare the results because of different entry criteria. Of 113 consecutive patients admitted with unstable angina, 89 who had primary angina were studied. Braunwald's classification was applied at admission. The outcomes of interest during hospitalization were coronary angiographic findings, short-term prognoses, and the treatment selected. Multivariate analysis showed that the severity class expressed significant positive predictivity for coronary thrombi (adjusted odds ratio [OR], 6.53; 95% confidence interval [CI], 2.82 to 15.1) and progress to impending infarction (OR, 10.43; CI, 3.35 to 32.49). The treatment (OR, 0.02; CI, 0.004 to 0.08) and electrocardiographic (OR, 0.22; CI 0.10 to 0.49) classes showed independent negative predictivity for coronary vasospasm. The treatment (OR, 3.50; CI, 1.94 to 6.33) and electrocardiographic (odds ratio, 3.27; CI, 1.87 to 5.71) classes showed positive predictivity for the necessity for recanalization treatment with coronary angioplasty or bypass grafting. The Braunwald classification used at admission is highly predictive of underlying coronary conditions, progression to impending infarction, and the final selection of treatment. This classification should be considered in determining patient eligibility in clinical trials and studies.

Prior myocardial infarction and prognostic outcome in patients with unstable angina in a postdischarge follow-up

The authors investigated how a previous myocardial infarction (MI) affects the prognosis of unstable angina pectoris in patients with maintained or slightly reduced left ventricular performance. From January 1991 to August 1993, 131 patients hospitalized with the diagnosis of Braunwald's class II-III unstable angina and ejection fraction > 40% were included. The enrolled patients were divided into two groups: (1) group I: unstable angina with prior MI (n = 70, 49 men, 21 women, aged between fifty-one and eighty years, mean: 65.7 +/- 8.5 years, Braunwald's class III: 71.4%), (2) group II: unstable angina with previous infarction (n = 61, 31 men, 30 women, aged between forty-nine and eighty, mean: 66.3 +/- 7.9 years, Braunwald's class III: 83.6%). The follow-up varied between six and twenty-four months. The frequency of major cardiovascular events (deaths, MI, reinfarction, heart failure, and recurrent unstable angina) and the number of revascularization procedures (percutaneous transluminal coronary angioplasty [PTCA] and coronary artery bypass grafting [CABG]) established during follow-up were evaluated. Hospitalization was 10.1 +/- 2.9 days in group I and 8.6 +/- 2.6 days in group II (P < 0.01). The duration of the follow-up was comparable between the two groups. Based upon predischarge noninvasive evaluation, patients in both groups were selected to undergo coronary and ventricular angiography: 38 of 70 (55.7%) in group I and 39 of 61 (62.3%) in group II; among them, 52.9% in group I and 24.6% in group II (P < 0.05) were submitted to coronary revascularization, while the others received medical treatments: 33 of 70 in group I and 46 of 61 in group II (P < 0.05). In the subset of patients submitted to angiography, the severity of coronary disease did not differ between the groups, and group I showed a statistically lower ejection fraction than group II (P < 0.005). The frequency of major cardiovascular events demonstrated a mortality rate of 2.9% in group I and 1.6% in group II. Acute MI/reinfarction accounted for 2.9% of the cases in group I and 3.3% in group II. Heart failure was present in 2.9% of group I. Recurrence of unstable angina was diagnosed in 11.4% of group I and 6.5% of group II. CABG and PTCA were performed, respectively in 7.1% and 5.7% in group I and in 6.6% and 4.9% in group II. During follow-up 75.7% of patients in group I and 80.3% in group II were asymptomatic. No significant differences in the frequency of cardiovascular events were reported between the two groups. As result of more aggressive therapeutic approaches following the detection of residual ischemia in patients with prior infarction, the authors conclude that the prognosis of unstable angina in the group with previous infarction does not seem to differ from that of unstable angina in the absence of prior necrosis in patients whose left ventricular function is maintained or slightly decreased.

CABG after successful PTCA: a case-control study

We sought characteristics predictive of the need for operative revascularization subsequent to a successful coronary angioplasty. Through June 1993, 128 patients who had successful percutaneous transluminal coronary angioplasty (PTCA) between January 1982 and March 1989 required subsequent coronary artery bypass grafting (CABG) at our hospital. These cases were matched with 128 controls who had a successful PTCA but did not require subsequent CABG. Controls were matched to cases by the date of their initial PTCA. Before initial PTCA there were no differences between the cases and controls in terms of age, sex, prior myocardial infarction, ejection fraction, duration of anginal symptoms, hypertension, hyperlipidemia, family history, or obesity (all not significant). A greater number of cases had diabetes (35 versus 18; p = 0.009). Angiography before initial PTCA revealed that cases had a greater mean number of total lesions (4.1 versus 3.3; p = 0.002) and a higher incidence of left anterior descending and circumflex artery stenoses of 70% or greater (98 versus 75 and 57 versus 34, respectively; p = 0.006). The mean number of lesions successfully dilated was greater in cases (2.4 versus 1.7; p = 0.0001). Cases had CABG at a mean interval of 16.7 +/- 23 months. There were 17 late deaths among cases and 9 among the controls at a mean of 38.6 +/- 30 months. The survival probability at 5 years was 94.5% for controls and 87.9% for cases (p = 0.048). Initial revascularization by PTCA is followed by CABG at a brief interval in a subset of patients who have markers of more severe disease than do patients who do not require early CABG.(ABSTRACT TRUNCATED AT 250 WORDS)

Relation of severity of symptoms to transient myocardial ischemia and prognosis in unstable angina

OBJECTIVES

This study was undertaken to compare the relative power of the severity of angina versus that of any other clinical, electrocardiographic (ECG) and angiographic findings in predicting the risk of subsequent in-hospital coronary events in patients admitted to the coronary care unit for treatment of unstable angina.

BACKGROUND

The presence or absence of chest pain has traditionally been used to guide management and therapy of unstable angina. However, recent studies raised the possibility that the cumulative duration of ischemia may be an additional index of prognosis.

METHODS

We studied 104 consecutive patients admitted to the coronary care unit because of unstable angina. Diaries of symptoms were accurately kept. All patients underwent Holter ambulatory ECG monitoring during the 1st 24 h and angiography within 1 week of admission.

RESULTS

During the hospital stay, 41 patients (group 1) had subsequent coronary events; the remaining 63 patients (group 2) had a good clinical outcome. Recurrence of chest pain after admission was observed in 76% of patients: 36 of the 41 group 1 patients (sensitivity 88%) and 43 of the 63 group 2 patients (specificity 32%). Anginal scores (frequency and persistence of pain, duration of each single episode and pain-free interval) showed high specificity but low sensitivity for detecting evolution toward subsequent coronary events. On Holter monitoring, the duration/24 h of the total number of ischemic episodes was consistently greater in group 1 than in group 2. A cumulative duration of ischemia > or = 60 min/24 h was observed in 34 of the 41 group 1 patients (sensitivity 83%) but in only 16 of the 63 group 2 patients (specificity 75%). High risk coronary artery lesions (left main coronary artery disease or complex stenosis) were detected in 36 of the 41 group 1 patients and in 26 of the 63 group 2 patients.

CONCLUSIONS

Transient myocardial ischemia detected by Holter monitoring, but not chest pain, is the best predictor of unfavorable short-term clinical outcome. The decision to perform early angiography and revascularization cannot be based on symptoms alone.

Aggressive clinical pattern of angina at restenosis following coronary angioplasty in unstable angina

The frequency, clinical pattern, and timing of recurrent angina following successful single-lesion percutaneous transluminal coronary angioplasty (PTCA) was assessed in a consecutive group of 104 patients with stable angina and in 85 with unstable angina. In addition, the relationship between lesion morphology and angiographic features and the pattern of recurrent angina was determined. Restenosis, defined as recurrence of symptoms with > 50% stenosis at the site of PTCA, occurred in 25 (24%) of the stable group and in 23 (27%) of the unstable group (p = NS). The pattern of angina at repeat presentation was aggressive in nature in 8% of the stable group and in 48% of the unstable group (p = 0.002). The time interval between the recurrence of symptoms and repeat coronary angiogram or PTCA was longer in the nonaggressive group than in the aggressive group, 16 +/- 12.1 and 5 +/- 6.8 weeks, respectively (p < 0.003). The key factors predicting the recurrent angina pattern identified by multiple logistic regression analysis were the angina status pre-PTCA (p = 0.001) and the presence of double-vessel disease (p = 0.01). An aggressive pattern of angina at the time of restenosis is frequent in patients with unstable angina at the time of PTCA, and close post-PTCA surveillance is necessary in these patients.

Angiographic morphology in unstable angina and its relation to transient myocardial ischemia and hospital outcome

Complex stenosis morphology frequently occurs in patients with unstable angina pectoris. However, its relation to transient myocardial ischemia and hospital outcome has not been ascertained. To address this issue, 88 patients with significant (greater than or equal to 50%) coronary artery disease presenting with angina--new onset (n = 38), worsening (n = 20) or at rest (n = 30)-were studied. Patients with left main artery disease, normal coronary arteries or occlusion of the ischemia-related arteries were not included in the study. Continuous electrocardiographic recordings were obtained during the first 24 hours. Angiography was performed within 1 week from admission. Complex morphology was defined as any stenosis with irregular borders, overhanging edges or intracoronary thrombus. Only data referring to the in-hospital outcome were considered in this study. Adverse end points were sudden death, myocardial infarction and emergency revascularization. Analysis of the angiograms revealed a complex morphology in 58 patients (group 1). The remaining 30 patients served as control subjects (group 2). Thirty-two of the 58 group 1 patients had an unfavorable clinical outcome (positive predictive value, 55%). A similar outcome occurred in only 2 of the 30 group 2 patients (negative predictive value, 93%). Of the 32 group 1 patients who had an unfavorable clinical outcome, 29 had a cumulative duration of transient myocardial ischemia of greater than or equal to 60 minutes per 24 hours. A similar duration of ischemia, however, was observed in another 6 group 1 and in 8 group 2 patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary artery disease in the octogenarian: angiographic spectrum and suitability for revascularization

The angiographic findings of 84 consecutive octogenarians presenting with symptoms of coronary artery disease (CAD) were examined to determine the extent of CAD as well as suitability for both coronary artery bypass grafting (CABG) and percutaneous transluminal coronary angioplasty (PTCA). The frequency of 0-, 1-, 2-, and 3-vessel and left main CAD was 7, 14, 21, 57 and 13%, respectively. Based on angiographic criteria, 69 of 78 patients (88%) with significant CAD had suitable coronary anatomy for CABG. Only 24 patients (31%) had coronary anatomy amenable to PTCA. CABG was performed in 19 patients with an operative mortality of 16% and major complication rate of 37%. PTCA was performed in 12 patients with a clinical success rate of 83%, mortality of 8% and major complication rate of 8%. It is concluded that in octogenarians with CAD, cardiac catheterization will often reveal coronary anatomy that is suitable for CABG but less suitable for PTCA. The morbidity and mortality associated with these interventions are high.

Unstable angina pectoris

The pathophysiology of unstable angina has been better elucidated in the past five years and has led to more rational therapy. Coronary arteries in patients with unstable angina have atherosclerotic plaques which are often complex and are the site of platelet activation and fibrin deposition. Nitrates, one of the oldest therapies, are efficacious and act not only by dilating coronary vessels but by reducing preload and afterload. Beta blockers have a salutary effect by decreasing myocardial oxygen demand. Calcium channel blockers attenuate smooth muscle contraction and thereby act to decrease coronary artery spasm. Beta blockers and calcium channel blockers are equally efficacious in unstable angina. The antiplatelet agent, aspirin, has been shown to reduce fatal or non-fatal myocardial infarction and probably overall mortality. The use of heparin acutely for unstable angina has been demonstrated to decrease refractory angina and myocardial infarction, and acutely is probably better than aspirin. For patients with reduced ejection fractions (0.30-0.49), a prospective randomized trial has shown that coronary artery bypass graft surgery offers an improved three-year survival compared with medical therapy; however, surgery does not prevent myocardial infarction. Percutaneous transluminal coronary angioplasty may be a reasonable therapeutic alternative for some patients with single-vessel disease who are refractory to medical therapy but there are as yet no controlled trials of this question. To date a clinical benefit from thrombolytic therapy has not been demonstrated.

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.

Influence of heparin therapy on percutaneous transluminal coronary angioplasty outcome in unstable angina pectoris

The acute procedural outcome of percutaneous transluminal coronary angioplasty in 304 patients with unstable angina was retrospectively examined with respect to the influence of prolonged preprocedural intravenous heparin therapy. Clinical and angiographic success in 135 patients receiving heparin therapy for greater than or equal to 24 hours was 91% while such success was noted in 81% of patients not treated with heparin (p = 0.02). The incidence of immediate postprocedural thrombotic vessel occlusion was higher in the nonheparin group than in the heparin-treated group (8.3 vs 1.5%, respectively, p less than 0.01). In addition, the overall rate of thromboembolic target and branch or distal vessel occlusion was 12.4% in the nonheparin group and 1.5% in the heparin-treated group (p less than 0.001). Thus, prolonged preprocedural intravenous heparin administration in this well-defined group of patients with unstable angina resulted in an improved procedural success rate and a significant decrease in the risk of abrupt vessel closure. These observations are concordant with current understanding of the pathophysiology of unstable angina.

Short-term and long-term benefits of coronary angioplasty in unstable angina pectoris

Primary coronary angioplasty was attempted in 288 patients (206 men and 82 women) who presented with stable (50%) or unstable (50%) angina pectoris. The success rates of angioplasty and the subsequent revascularization requirements in these two angina categories were compared during a one year prospective follow-up. The site and distribution of coronary artery stenoses did not differ between the categories. Three hundred and five dilatations were attempted (149 in 144 patients with unstable angina and 156 in 144 patients with stable angina). Of these procedures, 265 (87%) were technically successful--133 (89%) in 128 patients with unstable angina and 132 (85%) in 120 patients with stable angina. Lower success rates were achieved in 29 attempted dilatations of vessels with chronic total occlusion (19 successful [66%], P = 0.002) and in 19 patients who presented with unstable angina after recent (within two weeks) infarction (10 patients with successful angioplasty, [53%], P less than 0.0001). Subsequent revascularization requirements after an initially successful angioplasty in 57 patients were greater in unstable (36 patients) than in stable angina (21 patients; P = 0.05) and reflected the greater frequency of repeat angioplasty in patients with unstable angina (22 patients) compared with those with stable angina (10 patients; P = 0.04) among patients with recurrent symptoms. At one year, 245 patients (85%)-121 treated for unstable angina and 124 treated for stable angina--experienced no angina during normal daily activities. We conclude that a primary angioplasty success rate of 89% can be achieved in patients with unstable angina pectoris but this rate is significantly lower in patients presenting after recent infarction. Repeat angioplasty for recurrent symptoms after a successful primary procedure is required more frequently in patients presenting with unstable angina.

Angiographic and clinical characteristics of patients with unstable angina showing an ECG pattern indicating critical narrowing of the proximal LAD coronary artery

One hundred eighty of 1260 patients consecutively admitted to the hospital because of unstable angina pectoris had the typical ST-T segment changes suggestive of a critical stenosis in the proximal LAD. In 108 patients the ECG abnormalities were present at the time of admission. In the remaining 72 patients they developed shortly thereafter. The difference between these two groups was a longer duration of anginal complaints in the former (mean 2.3 days). Results of coronary angiography, performed a mean of 4.6 days after the last attack of chest pain, showed 50% or more narrowing in the proximal LAD in all patients. Thirty-three patients had complete occlusion of the LAD and 75 had collateral circulation to the LAD. Results of left ventricular angiography showed abnormal systolic left ventricular wall motion in 137 patients and normal systolic motion in the remaining 43 patients. The difference between these two groups was a shorter mean time interval between the last attack of chest pain and angiography in the former group (p less than 0.001). Twenty-four patients had only abnormal diastolic wall motion. Twenty-one patients had a small increase in the creatine kinase level at the time of admission. Fifteen patients (nine before and six during early revascularization) had an anterior wall myocardial infarction in the hospital; these patients had a patent but severely narrowed LAD and a low incidence of collateral circulation to the LAD.(ABSTRACT TRUNCATED AT 250 WORDS)