ical therapy is underway in the United States. Theprimary end points of angina class and exercisecapacity will be evaluated.

1. Kim CB, Kesten R, Javier M, Hayase M, Walton AS, Billingham ME, KernoffR, Oesterle SN. Percutaneous method of laser transmyocardial revascularization.Cathet Cardiovas Diagn1997;40:223–228.2. Mirhoseini M, Cayton MM. Revascularization of the heart by laser.J Micro-surg 1981;2:253–260.3. Mirhoseini M, Fisher JC, Cayton M. Myocardial revascularization by laser: aclinical report.Lasers Surg Med1983;3:241–245.4. Whittaker P, Kloner RA, Przyklenk K. Laser-mediated transmural myocardialchannels do not salvage acutely ischemic myocardium.J Am Coll Cardiol1993;22:302–309.

5. Krabatsch T, Scha¨per F, Leder C, Tu¨lsner J, Thalmann U, Hetzer R. Histo-logical findings after transmyocardial laser revascularization.J Card Surg1996;11:326–331.6. Kwong KF, Kanellopoulos GK, Nickols JC, Pogwizd S, Saffitz JE, SchuesslerRB, Sundt TM III. Transmyocardial laser treatment denervates canine myocar-dium. J Thorac Cardiovasc Surg1998; in press.7. Kohmoto T, DeRosa CM, Yamamoto N, Fisher P, Faily P, Smith CR, BurkhoffD. Evidence of vascular growth associated with laser treatment of normal caninemyocardium.Ann Thorac Surg1998; in press.8. Yamamoto N, Kohmoto T, Gu A, DeRosa CM, Smith CR, Burkhoff D.Angiogenesis is enhanced in ischemic canine myocardium by transmyocardiallaser revascularization.J Am Coll Cardiol1998; in press.9. Frazier OH, Cooley DA, Kadipasaoglu KA, Pehlivanoglu S, Lindenmeir M,Barasch E, Conger JL, Wilansky S, Moore WH. Myocardial revascularizationwith laser-preliminary findings.Circulation 1995; 92(suppl II):II-58–II-65.10. Horvath KA, Mannting F, Cummings N, Shernan SK, Cohn LH. Transmyo-cardial laser revascularization: operative techniques and clinical results at twoyears.J Thorac Cardiovasc Surg1996;111:1047–1053.

Prognosis of Medically Stabilized Unstable AnginaPectoris With a Negative Exercise Test

Raul Moreno, MD, Esteban Lopez de Sa, MD, Jose-Luis Lopez-Sendon, MD,Ana Ortega, MD, Maria-Jesus Fernandez, MD, Jaime Fernandez-Bobadilla, MD, and

Juan-Luis Delcan, MD

Patients with unstable angina pectoris (UAP) con-stitute an heterogeneous group with multiple

physiopathologic mechanisms, and therefore, a vari-able prognosis, with the death or acute myocardialinfarction rate at 1 year ranging from 13% to 25%.1–5

Patients with UAP refractory to medical treatment areusually recommended for cardiac catheterization.5 Al-though the management of patients with medicallystabilized UAP remains controversial,6 it is a frequentpractice to stratify future risk and identify those witha worse prognosis, and therefore, decide who couldbenefit by undergoing cardiac catheterization.5,7,8 Ex-ercise testing has been shown to be useful; those witha positive exercise test (ET) have a higher prevalenceof multivessel disease and a worse prognosis.5,7,8–21

However, 3% to 9% of patients with medical stabi-lized UAP and a negative ET experience myocardialinfarctions or die in a middle term follow-up.12–21

Therefore, although patients with a negative ET havea good prognosis as a group, there are subsets ofpatients with a worse prognosis who might hypothet-ically benefit from an aggressive approach. Accord-ingly, the aims of this study were: (1) to assess thelong-term prognosis of patients with UAP who weredischarged with a negative ET after medical control ofsymptoms, and (2) to identify the factors related witha worse prognosis.

• • •Patients admitted from January 1990 to December

1995 with UAP who had been medically stabilizedand discharged from medical treatment without coro-

nary revascularization after a negative ET were in-cluded in the study. UAP was diagnosed followingpreviously defined criteria.22 Patients were consideredstable when no new episodes of angina occurred$48hours before the study. Exercise testing was per-formed following the Bruce protocol.23 An ET wasconsidered positive when angina or ST segment de-pression.1 mm were present. The following clinicalvariables were studied: age, gender, type of UAP(resting, recent onset, progressive, or postinfarction);history of ischemic heart disease (myocardial infarc-tion, UAP, stable angina, percutaneous transluminalcoronary angioplasty, and coronary artery bypassgrafting), coronary risk factors (diabetes mellitus, his-tory of plasmatic cholesterol levels.240 mg/dl,smoking and high blood pressure), peripheral arterydisease, anti-ischemic treatment at discharge (nitrates,b blockers, calcium antagonists), and left ventricularejection fraction. The exercise testing parametersstudied were functional capacity, duration of exercise,and percentage of the maximum heart rate. The leftventricular ejection fraction was determined by 2-di-mensional echocardiography and was considered to benormal when.0.50, slightly depressed between 0.40to 0.50, moderately depressed between 0.30 to 0.40,and severely depressed when,0.30.

Follow-up of patients was made by telephone con-tact. The end-points were: (1) primary end-point:death or nonfatal myocardial infarction; and (2) sec-ondary: readmissions because of new episodes ofUAP and need for coronary revascularization (angio-plasty and/or bypass grafting).

Continuous variables were expressed as mean6SD and discrete variables as percentages. Data wereanalyzed with an actuarial survival method (Kaplan-Meier). An univariate analysis was performed with theStudent’s and Fisher’st tests to compare 2 mean

From the Department of Cardiology, Hospital Gregorio Maranon,Madrid, Spain. This study was supported by Mapfre Medicine, Ma-drid, Spain. Dr. Moreno’s address is: Department of Cardiology,Doctor Esquerdo, 46. Madrid 28007, Spain. Manuscript receivedNovember 24, 1997; revised manuscript received and acceptedApril 23, 1998.

662 ©1998 by Excerpta Medica, Inc. 0002-9149/98/$19.00All rights reserved. PII S0002-9149(98)00411-1

values, an analysis of variance test to compare.2mean values, and the chi-square test to compare pro-portions. Subsequently, a multivariate analysis wasperformed using the Cox proportional risk regressionmodel, including those variables associated with theend-points in the univariate analysis and those notassociated in the univariate analysis, but with prog-nostic value in previous studies. Intervals for riskratios are expressed as a 95% confidence interval.

Three hundred ninety-five patients met the inclu-sion criteria. Of these, 327 (83%) were followed up,during a mean of 39 months (median 41, range 1 to71). Baseline characteristics are summarized in TableI. Average age was 61.96 9.1 years, and 234 patients(72%) were men. One hundred four patients (32%)had a previous acute myocardial infarction and 78%had angina at rest. Mean duration of exercise was7.9 6 2.7 minutes, functional capacity was 8.96 2.9METs, and the percentage of the maximum heart ratewas 826 15%. The left ventricular ejection fractionwas normal in 275 patients (84%), slightly depressedin 25 (8%), moderately depressed in 19 (6%), andseverely depressed in 8 patients (2%).

During follow-up, 10.9% of the patients died, and11.1% experienced a nonfatal myocardial infarction(Kaplan-Meier method). Any of these 2 events oc-curred in 19.7% of the patients. The probability was6.1% during the first year and 11.8% at 39-monthfollow up. Therefore, survival without myocardial in-farction was 88.2% at 39 months and 80.3% at the endof follow-up.

Forty-five percent of patientswere readmitted because of new ep-isodes of UAP during follow-up(29% at the mean follow-up of 39months). Twenty-four percent of pa-tients required coronary revascular-ization during follow-up.

Variables statistically associatedwith the primary end-point (death ornonfatal myocardial infarction) inthe univariate analysis were: malegender (30.6% vs 7.3%; p5 0.023),previous infarction (30.1% vs 18.3%;p 5 0.002), and diabetes mellitus(58.7% vs 14.1%; p5 0,002). These 3variables were independent risk fac-tors in the multivariate analysis; therisk ratio (RR) was 1.57 (confidenceinterval [CI] 1.01 to 2.69; p5 0.05)for male gender, 1.44 (CI 1.03 to2.01; p5 0.032) for previous myo-cardial infarction, and 1.58 (CI 1.11to 2.21; p5 0.032) for diabetes mel-litus. The primary end-point was notassociated with the remaining clini-cal variables or ET parameters (du-ration of exercise, functional capac-ity, and percentage ofmaximum heartrate) in the univariate or multivariateanalysis (Table I).

Probability of readmission be-cause of new episodes of UAP was associated in theunivariate analysis with the following variables: hy-percholesterolemia (61% vs 39%; p5 0.001), diabe-tes mellitus (80% vs 32%; p,0.001), previous myo-cardial infarction (80% vs 31%; p,0.001), previousadmissions because of UAP (69% vs 38%; p,0.001),previous coronary angioplasty (74% vs 42%; p50.006), peripheral artery disease (73% vs 41%; p50.052), left ventricular dysfunction (78% vs 38%; p50.008), functional capacity,8 METs (54% vs 39%;p 5 0.019), percentage of the maximum heart rate,85% (54% vs 31%; p5 0.0237), and treatment withnitrates (62% vs 30%; p5 0.030). Only 3 of thesevariables were independent risk factors in the multi-variate analysis for readmissions because of new ep-isodes of UAP: previous myocardial infarction (RR1.50; CI 1.14 to 1.97; p5 0.004), hypercholesterol-emia (RR 1.38; CI 1.08 to 1.76; p5 0.010), anddiabetes mellitus (RR 1.55; CI 1.17 to 2.04; p50.003).

Variables associated with revascularization duringfollow-up in the univariate analysis were male gender(29% vs 12%, p5 0.025), previous myocardial in-farction (43% vs 16%; p,0.001), diabetes mellitus(45% vs 20%; p,0.001), hypercholesterolemia (31%vs 20%; p 5 0.049), and peripheral artery disease(32% vs 23%; p5 0.039). In the multivariate analysis,the following were predictors for coronary revascular-ization: male gender (RR 1.46; CI 1.01 to 2.29; p50.049), previous myocardial infarction (RR 1.52; CI

TABLE I Baseline Characteristics and Rate (%) of Death or Nonfatal MyocardialInfarction in Different Subgroups of Patients (Kaplan-Meier survival method)

Baseline Yes No p Value

Age .65 years 107 (34%) 23.3 19.6 NSMen 234 (72%) 30.6 7.3 0.0229Smoking 196 (60%) 18.3 24.2 NSHypercholesterolemia 124 (38%) 28.2 18.3 NSDiabetes mellitus 62 (19%) 58.7 14.1 0.0020High blood pressure 154 (47%) 19.5 21.0 NSPrevious myocardial infarction 104 (32%) 30.1 18.3 0.0016Previous UAP admission 75 (23%) 17.8 24.6 NSPrevious stable angina 51 (16%) 26.4 21.7 NSPrevious coronary angioplasty 32 (10%) 3.5 22.5 NSPrevious coronary bypass 22 (7%) 27.7 22.1 NSPeripheral artery disease 29 (9%) 31.6 22.7 NSType of UAP:

Rest 257 (78%) 21.7 22.5 NSRecent onset 43 (13%) 26.1 21.3 NS

Progressive 21 (7%) 21.3 22.4 NSPostinfarction 6 (2%) 25.0 22.1 NS

Left ventricular dysfunction 52 (16%) 21.4 19.3 NSExercise test

$8 METs 199 (64%) 15.5 31.8 NS$8 min 161 (52%) 17.0 26.2 NS$85% maximum heart rate 136 (44%) 14.6 26.8 NS

TreatmentNitrates 183 (56%) 17.7 23.7 NSb blockers 65 (20%) 22.8 24.1 NSDiltiazem/verapamil 180 (55%) 26.7 16.5 NSDihydropyridines 59 (18%) 18.3 25.0 NS

Yes 5 death/infarction rate in patients in whom characteristic is present; No 5 death/infarction inpatients in whom characteristic is absent.

BRIEF REPORTS 663

1.13 to 2.05; p5 0.006), and diabetes mellitus (RR1.63; CI 1.18 to 2.20; p5 0.003).

• • •In this study, the rate of death or nonfatal myocar-

dial infarction at the first year in patients with medi-cally stabilized UAP and a negative ET was 6%. Thisresult is concordant with previous studies, which showa 1-year mortality rate of 3% to 9%.12,17 This prog-nosis is better than that described for the whole groupof patients with UAP. The patients in the persent studyare a selected population with UAP, because nonre-currence of angina and control under pharmacologictreatment predict a better prognosis,4,24 and patientswith medically stabilized UAP and a negative ET havea lower future risk of myocardial infarction or death.However, in the present series of patients with medi-cally stabilized UAP and a negative ET, the 71-monthmortality or nonfatal myocardial infarction rate was20%, showing that these patients do not have a lowfuture risk when only receiving medical treatment.Thus, patients with medically stabilized UAP whohave a negative ET, although they have a better prog-nosis than those with a positive ET, have a consider-able rate of myocardial infarction or death.

In the present study, exercise parameters were notpredictors of a bad prognosis. Exercise testing param-eters have demonstrated a high prognostic value inpatients with ischemic heart disease. Patients of thepresent study constitute a selected population, becausethose in whom the ET was completed, because of

angina or ST depression, had been excluded. This maybe the explanation for the absence of prognostic valueof exercise parameters in patients with medically sta-bilized UAP and a negative ET.

In contrast, male gender, diabetes mellitus, andprevious myocardial infarction were associated with ahigher rate of death or nonfatal myocardial infarction.Diabetes mellitus is associated with more extendedand quickly progressive coronary artery disease and aworse prognosis.25 The presence of previous myocar-dial infarction is associated with a higher prevalenceof multivessel disease and left ventricular dysfunction;these are both associated with a worse prognosis.21,26

Women probably have a higher prevalence of micro-vascular angina and a lower probability of epicardialcoronary disease. Conversely, male gender is associ-ated with a higher prevalence of epicardial coronarydisease and multivessel disease.26–30 Although in pa-tients with acute myocardial infarction female genderis correlated with a worse prognosis, most womenexperiencing a myocardial infarction have epicardialcoronary disease; thus patients with infarction andthose with medically stabilized UAP and a negativeET are not comparable populations.

Thus, management of patients with medically sta-bilized UAP and a negative ET should be based onclinical variables, rather than exercise parameters.However, it cannot be concluded that patients with abad prognosis necessarily benefit from an aggressiveapproach, and further research is needed to ascertain ifcardiac catheterization and coronary revascularizationimprove the prognosis in these patients.

The absence of the prognostic values of age andleft ventricular function is probably due to the selec-tion criteria. Most patients with a severely depressedleft ventricular ejection fraction are usually recom-mended for cardiac catheterization and revasculariza-tion, which explains the low proportion of patientswith left ventricular dysfunction and its absence ofprognostic significance in the present study. On theother hand, elderly patients usually undergo dobut-amine echocardiography or radionuclide methods andnot exercise testing; thus, the low proportion of el-derly patients may explain the absence of statisticalassociation between age and prognosis.

Lastly, it must be emphasized that the type ofmedical treatment did not influence prognosis. It isprobably more important to achieve clinical stabiliza-tion of UAP without ischemia during the ET, regard-less of the type of anti-ischemic treatment.

The best medical therapy for patients with UAP asa group remains controversial, but management ofmedically stabilized UAP with a negative ET is evenmore unclear. The prognostic significance of exercisetesting parameters has not been defined in patientswith stabilized UAP and a negative ET. However,although it has not been demonstrated, it has beenclassically considered that those with a lower func-tional capacity, duration of exercise, and heart ratehave a worse prognosis. In this way, a frequent prac-tice, at least in Europe, is to submit for cardiac cath-

TABLE II Readmission Because of New Episodes of UnstableAngina Pectoris (UAP) (%) in Different Subgroups of Patients(Kaplan-Meier)

Yes No p Value

Age .65 years 42.2 46.8 NSMale gender 51.3 32.6 NSSmoking 49.1 42.8 NSHypercholesterolemia 60.8 38.9 0.0013Diabetes mellitus 80.3 31.5 ,0.0001High blood pressure 42.5 49.1 NSPrevious myocardial infarction 79.5 30.7 ,0.0001Previous UAP-admissions 69.2 37.8 0.0006Stable angina 45.8 45.2 NSPrevious coronary angioplasty 73.7 42.3 0.0064Previous coronary bypass 84.5 41.6 NSPeripheral artery disease 73.3 41.4 0.0520Type of UAP

Rest 46.6 36.5 NSRecent onset 37.9 45.5 NS

Progressive 34.1 45.6 NSPostinfarction 20.0 45.4 NS

Left ventricular dysfunction 78.2 38.4 0.0077Exercise test

$8 METs 39.4 54.4 0.0192$8 minutes 43.2 46.3 NS$85% maximum heart rate 31.4 54.4 0.0237

Treatment:Nitrates 61.5 29.6 0.0298b blockers 48.8 44.4 NSDiltiazem/verapamil 52.0 36.2 0.0937Dihydropyridines 48.0 44.4 NS

Yes 5 new episodes rate in patients in whom characteristic is present; No 5

new UA episodes rate in patients in whom characteristic is absent.

664 THE AMERICAN JOURNAL OF CARDIOLOGYT VOL. 82 SEPTEMBER 1, 1998

eterization those patients with low exercise testingparameters, but no ischemia at the ET.

The results of this study suggest that it is easy toidentify subgroups of patients with a worse prognosisamong those with stabilized UAP and a negative ETwhen considering simple clinical variables. Male pa-tients with diabetes mellitus and previous myocardialinfarctions could be considered as candidates for amore aggressive management, based independently onthe exercise testing parameters. If this approachshould prove to be beneficial, it should be establishedin prospective and controlled trials.

In conclusion, 20% of patients with UAP, whohave a negative ET after having been medicallystabilized and discharged from medical treatment,die or suffer a nonfatal myocardial infarction dur-ing a follow-up of 71 months. Diabetes mellitus,male gender, and previous myocardial infarction,but not exercise testing parameters, are indepen-dent risk factors for death or myocardial infarc-tion. Thus, the selection of patients with UAP anda negative ET for cardiac catheterization should bebased on clinical variables (diabetes mellitus, malegender, and previous myocardial infarction) ratherthan exercise testing parameters.

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