Early postinfarction ischemia: clinical, angiographic, and prognostic significance

Early ischemia, defined as angina with transient ST-T changes during hospitalization, 24 hr or more after an acute myocardial infarction (MI), was observed in 79 (18%) of a consecutive series of 449 patients surviving an MI and catheterized a mean of 10 +/- 3 days after admission. Three clinical factors present 24 hr after admission could identify patients at low, medium, and high risk of factors had a risk greater than 50% and the 118 patients with Q wave MI, no previous angina, and absence of risk factors had a risk of less than 8%. The angiographic correlates of early ischemia were number of vessels with 70% or more stenosis (2.1 +/- 0.8 vs 1.7 +/- 0.8/patient, p less than .0001), number of diseased coronary artery segments (2.8 +/- 1.4 vs 2.1 +/- 1.2, p less than .0001), left anterior descending coronary involvement (77% vs 62% of patients, p = .01), number of normally contractile segments at jeopardy because of a coronary stenosis (1.9 +/- 1.3 vs 1.3 +/- 1.1/patient, p less than .0002), collateral circulation at jeopardy (24% vs 15% of patients, p less than .005), and fewer collateral vessels distal to a tight stenosis (59 vs 72% of patients, p = .04). The stepwise logistic regression retained one angiographic and two clinical independent predictors of early ischemia: number of diseased vessels (p = .0008), presence of a non-Q wave MI (p = .0027), and previous angina (p = .017).(ABSTRACT TRUNCATED AT 250 WORDS)     

ST segment shift in unstable angina: pathophysiology and association with coronary anatomy and hospital outcome

The significance of ST segment shift with respect to coronary anatomy and hospital outcome was evaluated in 135 patients with unstable angina. ST shift was evident in 44% of patients on admission electrocardiogram (ECG) and in 66% on Holter monitor ECG. During hospitalization, 7% of patients had myocardial infarction, 4% died and 34% had urgent coronary revascularization. By comparing patients with and without ST shift on admission ECG, an unfavorable outcome was found in 55% versus 25% (p less than 0.005), multivessel disease in 77% versus 63% (p less than 0.05) and left main coronary artery stenosis in 22% versus 7% (p less than 0.025). When patients with and without ST shift on Holter monitor ECG were compared, an unfavorable outcome was found in 48% versus 20% (p less than 0.005), multivessel disease in 76% versus 54% (p less than 0.01) and left main coronary stenosis in 18% versus 4% (p less than 0.05). The duration of ST shift was also greater in patients with 1) unfavorable outcome (129 +/- 136 versus 52 +/- 111 min, p less than 0.01); 2) multivessel disease (98 +/- 129 versus 36 +/- 90 min, p less than 0.01); and 3) left main stenosis (150 +/- 147 versus 67 +/- 114 min, p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)     

Unstable angina: individualized stratification and prognosis.

OBJECTIVE: To analyse the methodology of risk stratification and the prognosis of patients admitted with unstable angina. POPULATION AND METHODS: This retrospective study involved a population of 68 patients (43 males and 25 females with a mean age of 65.8 +/- 9.8 years) consecutively admitted for suspected unstable angina during the year of 1996. Thirty six patients (52.9%) had angina at rest, 13 patients (19.1%) had both exertional and rest angina, 9 patients (13.2%) crescendo angina, 6 patients (8.8%) new onset exertional angina (less than 1 month), and 4 patients (5.8%) post-infarction angina (less than 2 weeks). The risk stratification was individualized. The coronary angiography (35 patients) was only performed when the medical therapy failed in patients with recurrent angina, or with proved ischemia after an exercise test and/or thallium 201 stress scintigraphy. Thirteen patients (19.1%) did not undergo these tests (advanced age and or bad general condition, or refusal). The follow-up of patients with and without ST-T changes was compared, as well as those revascularized versus non-revascularized. It was possible to achieve a mean follow-up of 13.7 +/- 6.2 months (3 to 25 months). RESULTS: The exercise test and/or thallium-201 stress scintigraphy were positive for myocardial ischemia in 28 pts (41.1%) and negative in 7 patients (10.2%). The coronary angiography revealed three-vessel coronary artery disease in 18 patients (26.4%), one vessel disease in 11 patients (16.1%) and two-vessel disease in 5 patients (7.3%). One patient had normal coronary arteries. Medical therapy was the initial approach. Coronary surgery was urgently performed in 3 patients and coronary angioplasty in 5 patients for refractory unstable angina. In the whole group coronary artery surgery was undertaken in 14 patients (20.5%) and coronary angioplasty in 12 patients (17.6%). A mean follow-up of 13.7 +/- 6.2 months was obtained in the 68 patients. During this period 6 patients (8.8%) died due to cardiac causes and 16 patients (23.5%) were readmitted: 8 patients (11.7%) for unstable angina, 5 patients (7.3%) for congestive heart failure and 3 patients (4.4%) for myocardial infarction. Fifty two patients (76.4%) remained free of cardiac events. The patients with transitory ST-T changes had more cardiac events (unstable angina, myocardial infarction, mortality) than the patients without ECG changes (13/30 vs 2/30, p = 0.003). When the revascularized patients were compared to the non revascularized no significant differences were observed regarding myocardial infarction and mortality, however revascularized pts had a less significant incidence of rehospitalization for unstable angina (0/26 vs 8/42 p = 0.02). CONCLUSIONS: An individualized strategy can be effective in pts with unstable angina. In this study 76.4% of patients remained free of cardiac events during the follow-up, 23.6% had severe cardiac events and the cardiac mortality was 8.8%. The patients with transitory ST-T changes had more cardiac events and worse prognosis. No patients significant difference was observed in the revascularized versus non revascularized patients for myocardial infarction and mortality; however, the revascularized patients had less significant incidence of rehospitalization for unstable angina.     

Role of perceptive threshold in myocardial infarction patients without previous angina

The purpose of this study is to clarify the mechanism of sudden onset myocardial infarction (MI) without previous angina and the relationship of MI without previous angina to the mechanism of onset of postinfarction asymptomatic myocardial ischemia. The mean initial time of ischemic pain in the upper arm under the tourniquet test was significantly prolonged in the MI patients without previous angina, compared with that for the MI patients with previous angina and normal control subjects, although there are some overlapping cases (74 +/- 37 sec versus 52 +/- 20 sec (p less than 0.01), and versus 56 +/- 15 sec (p less than 0.05), respectively). The tolerance time for ischemic pain also was similarly prolonged. There was no significant difference between the groups of MI patients (with and without previous angina) with respect to age, frequency of complications of diabetes mellitus, severity of coronary artery lesions or site of MI. The incidence of post-infarction myocardial ischemia was 50% for the previous angina group and 39.5% for the group without previous angina, but the frequency of asymptomatic ischemia was significantly higher in patients without previous angina, at 66.7%, than in those with previous angina, 32.3% (p less than 0.05). These results suggest that there is a close relationship between the mechanism of MI with sudden onset and that of asymptomatic myocardial ischemia during the pre- and post-infarction periods in patients with low sensitivity to pain.     

Angiographic characteristics of the infarct-related coronary artery in patients with angina pectoris after myocardial infarction

To elucidate the pathophysiology of angina pectoris after myocardial infarction, we analyzed the coronary stenoses in 45 subjects (28 men, 17 women, aged 33 to 67 years) with recent (less than or equal to 60 days) infarction, significant narrowing of only the infarct-related artery, and residual anterograde flow in this artery. Postinfarction angina was absent in 19 (group I) and present in 26 (group II). The groups were similar in age, left ventricular function, incidence with which each coronary artery was involved, as well as stenosis diameter (1.0 +/- 0.3 vs 0.9 +/- 0.4 mm [mean +/- standard deviation], respectively, difference not significant), stenosis area (0.9 +/- 0.4 vs 0.8 +/- 0.8 mm2, respectively, difference not significant), percent diameter narrowing (65 +/- 5 vs 66 +/- 9, respectively, difference not significant), and stenosis eccentricity. However, those with postinfarction angina had longer stenoses (group I, 4.3 +/- 1.4 mm; group II, 10.3 +/- 4.0 mm; p less than 0.001). Thus, patients with postinfarction angina and residual anterograde flow in the infarct artery may have angina due to a marked reduction in anterograde flow, caused by a long stenosis. There is no apparent relation between stenosis eccentricity and postinfarction angina.     

Anginal symptoms without ischemic electrocardiographic changes during ambulatory monitoring in men with coronary artery disease

Episodes of angina pectoris without electrocardiographic (ECG) signs of myocardial ischemia during 24-hour ambulatory monitoring were studied in 128 patients with a history of stable angina, angiographically proven coronary artery disease and positive exercise test results. In all, 341 episodes of ischemic ECG changes (ST-segment depression greater than 1 mm for greater than 1 minute) and 190 episodes of angina pectoris were observed: 86 episodes consisted of both ECG changes and angina pectoris, 255 episodes consisted only of ECG changes, and 104 episodes only of angina pectoris. Duration and magnitude of ST-segment deviation and heart rate at the onset of ischemia were similar in the 86 symptomatic and the 255 asymptomatic episodes with ECG changes. The 104 episodes of angina pectoris without ECG changes were detected in 44 patients (34%) (group A); 29 of them had only episodes with angina pectoris and 15 patients had both--episodes of angina pectoris with and without ECG changes. In 84 patients (66%) (group B) angina pectoris without ECG changes was not observed; all episodes were accompanied by ischemic ECG changes in these patients. No differences in the angiographic extent of coronary artery disease and in exercise test data were seen in both groups A and B; however, maximal ST-segment depression during exercise testing was significantly greater in group B than in group A patients (2.4 +/- 0.8 mm vs 1.9 +/- 0.9 mm; p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)     

Myocardial infarction after coronary bypass surgery. Associated factors and prognosis

This paper studies the factors associated with perioperative myocardial infarction after coronary bypass surgery and assesses the medium-term prognosis of these patients. Four hundred and seventy patients underwent coronary bypass surgery between January 1983 and December 1986. The appearance and persistence of pathological Q waves, absent on the preoperative ECG, was the unique criterion of perioperative infarction. This complication was observed in 36 patients (7.65%). A comparison of these patients with a random group of 144 of teh 434 patients without perioperative infarction showed that they had a higher incidence of crescendo angina (55% vs 21%; p less than 0.001), ST-T wave changes on the resting ECG (78% vs 46%; p less than 0.001) and poor distal left anterior descending network (33% vs 13%; p less than 0.001): in addition, the group with infarction had a lower left ventricular ejection fraction (0.58 vs 0.64, p less than 0.01), incomplete myocardial revascularisation procedures (58% vs 32%; p less than 0.01), longer cardiopulmonary bypass times (86 mn vs 69 mn; p less than 0.001) and longer aortic clamping times (44.5 mn vs 37.4 mn p less than 0.05). The acute phase of the perioperative infarct was characterised by a higher incidence of major cardiac complications such as low output states (30.5% vs 2.02%; p less than 0.001). The hospital mortality was higher in the infarct group (8.3% vs 2.01%) but this was not statistically significant. After an average follow-up of 44 +/- 3 months, the 5 year survival rate was 95.4 +/- 2.1 per cent in patients without infarction and 76.5 +/- 6.9 per cent in those with perioperative infarction (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)     

Prognostic significance and beneficial effect of diltiazem on the incidence of early recurrent ischemia after non-Q-wave myocardial infarction: results from the Multicenter Diltiazem Reinfarction Study

Of 576 patients with non-Q-wave acute myocardial infarction enrolled in the Diltiazem Reinfarction Study, 246 (43%) had 1 or more episodes of angina at rest or with minimal effort during 10.5 days of treatment with either diltiazem (90 mg every 6 hours) or placebo. Reinfarction (12.2% vs 3.6%, p less than 0.0001) or death (6.1% vs 1.5%, p = 0.003) was more likely to occur within 2 weeks of randomization in patients with postinfarction angina than in those without angina. Based on serial electrocardiographic data, 115 of the 246 patients with angina had transient ST-T changes and 131 did not. Comparison of the 14-day event rates in these 2 groups showed that the 115 patients with electrocardiographic evidence of ischemia had a higher frequency of reinfarction (20% vs 5.3%, p less than 0.001), more extensive damage as assessed by peak MB-creatine kinase levels (91 +/- 76 vs 37 +/- 19 IU/liter, p = 0.059 [Wilcoxon rank sum]) and a higher mortality rate (11.3% vs 1.5%, p = 0.001). Angina associated with transient ST-T changes occurred in 70 of the 289 patients in the placebo group but in only 45 of the 287 patients in the diltiazem group--a 28% reduction in cumulative life-table incidence (p = 0.0103 [2-tail, log rank]; 95% confidence interval, 9.3 to 53.8%). It is concluded that patients with early postinfarction angina are at increased risk of reinfarction and death, and angina associated with transient electrocardiographic changes identified a very high risk subset. This subset appeared to have a larger area of viable but jeopardized myocardium and benefited from prophylactic therapy with diltiazem.     

Comparative predictive value of ST-segment depression or angina during early and repeat postinfarction exercise tests

To determine the relative value of electrocardiographic (ECG) ST-segment depression alone compared to angina alone for predicting multivessel coronary artery disease during early and repeat postinfarction exercise tests, we evaluated 93 postmyocardial infarction patients with modified treadmill exercise tests prior to hospital discharge (mean 14 +/- 2 days), and 36 of these 93 patients with repeat exercise tests at six weeks following infarction. It was concluded that angina alone or angina irrespective of the presence of ST-segment depression are better predictors of multivessel coronary artery disease than ECG ST-segment depression alone, and the persistence of ischemic abnormalities during repeat treadmill exercise tests following infarction is useful for confirming the presence of multivessel coronary artery disease.     

Can the exercise test with nitroglycerin be useful for differentiation of patients with and without changes in coronary arteries--syndrome X?

The aim of this study was to compare the results of ECG exercise test performed before and after oral administration of nitroglycerine (NTG) in patients with coronary artery disease (CAD), and patients with typical chest pain without any changes in coronary arteriography--syndrome X. We examined 98 patients with typical chest pain, positive result of ECG exercise test, then accordingly to results of coronary arteries assessed with coronary arteriography, patients (pts.) were divided into two groups: group 1--35 pts. without any changes in coronary arteriography--syndrome X, and group 2--48 pts. with significant stenosis present in one or more coronary vessels. Each patient underwent two ECG exercise tests: first without any medication and second performed average 30 minutes after first test, and 5 min after oral administration of 1 table of nitroglycerine. During both tests the following parameters were evaluated: test duration, presence of chest pain, max. ST-T changes, heart rate (HR), and systolic blood pressure (SBP). RESULTS: In group 1 after NTG time of test duration had shortened from 5.9 +/- 0.4 min to 5.7 +/- 0.6 min. We also observed an increase in max. ST-T complex depression (2.2 +/- 0.5 mm vs 2.4 +/- 0.4 mm) but these differences were not statistically significant. In CAD group, duration of test after NTG was longer (6.2 +/- 1 vs 7.4 +/- 1.2), and normalization of max. ST-T complex depressions (2.7 +/- 0.5 vs 2.0 +/- 0.3 mm) was observed p < 0.01. CONCLUSION: Our study suggests that ECG exercise test with NTG may be useful in differentiation of patients with syndrome X and patients with typical coronary artery disease.     

Impact of thallium-201 imaging on clinical assessment and management of patients with chest pain

The histories, rest, and exercise ECG results of 60 patients without myocardial infarction complaining of chest pain were submitted to 6 physicians (3 cardiologists and 3 noncardiologists) who were unaware of the angiographic findings. The physicians were requested to estimate the probability of coronary artery disease present in percentages and to assess the need for coronary angiography on a five-point scale (1 = definitely not indicated, 5 = definitely indicated). After obtaining the results of thallium-201 imaging following dipyridamole (0.50 mg/kg intravenously) administration, the physicians were again requested to estimate probability and need for angiography. In the 43 patients with coronary artery disease the judgment of probability was increased significantly after 201Tl from 75.6 +/- 20.2% to 82.9 +/- 23.2% (p less than 0.001) and the need for angiography from 4.3 +/- 0.9% to 4.5 +/- 0.9% (p less than 0.001). In the subgroup of patients with atypical angina the relative change in probability was higher than in other subgroups of patients with coronary artery disease. In the 17 patients with normal coronary arteries the probability estimation fell after 201Tl from 36.7 +/- 22.0% to 24.8 +/- 21.0% (p less than 0.001), the need for angiography was decreased from 2.7 +/- 1.1% to 2.2 +/- 1.2% (p less than 0.001). With the 201Tl information, cardiologists performed a better diagnostic differentiation of patients with and without coronary artery disease than noncardiologists. The study demonstrates the improvement of clinical diagnosis in patients with chest pain by thallium-201 imaging and confirms the favorable influence of the method on the management of the patients in terms of indications for coronary angiography.     

Technetium-99m sestamibi tomography in patients with spontaneous chest pain: correlations with clinical, electrocardiographic and angiographic findings.

The sensitivity and specificity of technetium-99m hexakis-2-methoxy-2-isobutyl-isonitrile (sestamibi) single-photon emission computed tomographic (SPECT) imaging for the diagnosis of coronary artery disease were studied in 45 patients admitted to the hospital for clinical suspicion of unstable angina. Only patients without prior myocardial infarction were included and all patients had technetium-99m sestamibi injection and a 12-lead electrocardiogram (ECG) during and less than or equal to 4 h after an episode of chest pain. Coronary angiography performed in all patients during hospitalization showed significant coronary artery disease (greater than or equal to 50% luminal diameter reduction) in 26 of the 45 patients. The SPECT studies obtained after injection of technetium-99m sestamibi during an episode of spontaneous chest pain showed a sensitivity of 96% for the detection of coronary artery disease; the 12-lead ECG obtained at the time of the injection had a sensitivity of 35%. With the patient in the pain-free state, respective sensitivity values were 65% and 38%. Specificity for the radionuclide study was 79% during pain and 84% in the pain-free state; for the ECG, it was 74% both during and between episodes of pain. The site of the perfusion defect corresponded to the most severe coronary artery lesion in 88% of patients. The severity of the perfusion defect correlated with the extent of coronary artery disease: the defect score was 5.3 +/- 3.3 with one-vessel disease, 4.9 +/- 2.8 with two-vessel disease and 10.5 +/- 5.0 with three-vessel disease (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)     

Dynamic limitation of coronary vasodilator reserve in patients with dilated cardiomyopathy and chest pain

Twenty-six patients with dilated cardiomyopathy and angiographically normal coronary arteries, 12 of whom gave a history of anginal chest pain, underwent noninvasive and invasive hemodynamic study. During treadmill exercise testing, patients with a history of angina demonstrated worse effort tolerance (7.4 +/- 4.9 versus 13.6 +/- 5.1 minutes, p less than 0.005) and a lower end-exercise systolic blood pressure-heart rate product (17.9 +/- 3.4 versus 23.6 +/- 4.9 mm Hg.beats/min x 10(3), p less than 0.005) compared with patients without a history of angina. During rapid atrial pacing after ergonovine, 0.15 mg intravenously, 11 of the 12 patients with a history of angina experienced their typical chest pain, in contrast to only 1 of 12 patients without a history of angina. The angina group, compared with the nonangina group, had significantly lower great cardiac vein flow (118 +/- 24 versus 160 +/- 43 ml/min, p less than 0.01), and higher coronary resistance (0.87 +/- 0.21 versus 0.66 +/- 0.25 mm Hg.min/ml, p less than 0.05), significant widening of the arterial--great cardiac vein oxygen difference and a significant fall in cardiac index during pacing. Further, ergonovine resulted in higher coronary resistance during pacing in the angina group compared with pacing alone (+0.16 +/- 0.16 mm Hg min/ml, p less than 0.01), in the absence of significant reduction in epicardial coronary artery luminal diameter. After dipyridamole, 0.5 to 0.75 mg/kg intravenously, to 21 patients, the 7 patients with a history of angina had significantly lower flow (149 +/- 37 versus 218 +/- 73 ml/min, p less than 0.05) and higher coronary resistance (0.59 +/- 0.09 versus 0.43 +/- 0.17 mm Hg.min/ml, p less than 0.05) than did the nonangina group. It is concluded that patients with dilated cardiomyopathy and chest pain unrelated to epicardial coronary artery disease exhibit impaired vasodilator responses to both metabolic and pharmacologic stimuli, and an increased sensitivity to the vasoconstrictor effects of ergonovine. Whether these findings are of etiologic or long-term prognostic significance is unknown.     

Coronary angiographic significance of left anterior fascicular block during acute myocardial infarction

The clinical and angiographic significance of isolated left anterior fascicular block occurring during the early stage of acute myocardial infarction was studied in 141 consecutive patients who underwent cardiac catheterization before hospital discharge. Left anterior fascicular block occurred in 15 of the 62 patients with an anterior wall infarction and in 13 of the 79 with an inferior infarction. None of the clinical characteristics differed among patients with or without left anterior fascicular block. The number of coronary vessels with significant stenosis, the Friesinger and the Gensini scores for severity of stenosis and the ejection fraction were also similar in the two groups. Patients with left anterior fascicular block had more severe narrowing of the coronary artery supplying the infarct zone (88 +/- 21 versus 70 +/- 35%, p less than 0.001) and tended to have less developed collateral circulation (collateral score 0.7 +/- 0.8 versus 1 +/- 0.8, p = 0.10). A significant stenosis of the left anterior descending coronary artery was found as frequently in patients with as in those without left anterior fascicular block (64 versus 65%); 29% of the patients with inferior wall infarction and left anterior fascicular block had left anterior descending coronary artery stenosis compared with 47% of the patients without this conduction disturbance (no significant difference). When the infarction was located anteriorly, a significant stenosis of the proximal segment of the left anterior descending coronary artery was present in 47% of the patients with and in 45% of the patients without left anterior fascicular block.(ABSTRACT TRUNCATED AT 250 WORDS)     

Coronary bypass surgery improves global and regional left ventricular function following thrombolytic therapy for acute myocardial infarction. TAMI Study Group

Coronary bypass surgery was performed prior to hospital discharge in 303 (22%) of 1387 consecutive patients enrolled in the TAMI 1 to 3 and 5 trials of intravenous thrombolytic therapy for acute myocardial infarction. Bypass surgery was of emergency nature (less than 24 hours from treatment with intravenous thrombolytic therapy) in 36 (2.6%) and was deferred (greater than 24 hours) in 267 (19.3%) patients. The indications for bypass surgery included failed angioplasty (12%); left main or equivalent coronary disease (9%); complex or multivessel coronary disease (62%); recurrent postinfarction angina (13%); and refractory pump dysfunction, mitral regurgitation, ventricular septal rupture or abnormal predischarge functional test (1% each). Although patients having bypass surgery were older (59.5 +/- 9.8 versus 56.0 +/- 10.2 years, (p less than 0.0001), had more extensive coronary artery disease (46% with three-vessel disease versus 11%, (p less than 0.0001), had more frequent diabetes mellitus (19% versus 15%, (p = 0.048), had more prior infarctions (p less than 0.0001), had more severe initial depression in global left ventricular ejection fraction (48.0 +/- 11.9% versus 51.8 +/- 11.9%, p = 0.0002), and regional infarct zone (-2.7 +/- 0.94 versus -2.5 +/- 1.1 SD/chord, p = 0.02) and noninfarct zone function (-0.36 +/- 1.8 versus 0.43 +/- 1.6 SD/chord, p less than 0.0001) than patients not having coronary bypass surgery, no difference in the incidence of death in hospital (7% surgical versus 6% nonsurgical) or death at long-term follow-up of hospital survivors (7% surgical versus 6% nonsurgical) was noted between groups. Surgical patients demonstrated a greater degree of recovery in left ventricular ejection fraction (3.4 +/- 9.8% versus 0.16 +/- 8.5%, p = 0.036) and infarct zone regional function (0.71 +/- 1.1 versus 0.34 +/- 0.99 SD/chord, p = 0.001) when immediate (90 minutes following initiation of thrombolytic therapy) and predischarge (7 to 14 days after treatment) contrast left ventriculograms were compared than did patients who received only intravenous thrombolytic therapy with or without coronary angioplasty. These data suggest a beneficial influence of coronary bypass surgery on left ventricular function and possibly on the clinical outcome of patients initially treated with intravenous thrombolytic therapy for acute myocardial infarction.     

Evaluation of coronary flow reserve in patients with vasospastic angina

OBJECTIVES: The presence of microvascluar impairment was evaluated in 154 patients with vasospastic angina identified by the acetylcholine provocation test. METHODS: Coronary flow reserve was evaluated with a Doppler flow guidewire in 128 vessels of 72 patients with chest pain, but no significant coronary stenosis(less than 50% stenosis) and no clinical factors that affect coronary flow reserve. Coronary flow reserve was obtained from the ratio of adenosine triphosphate-induced maximum/baseline averaged peak velocity. These vessels were classified into 2 categories according to whether acetylcholine-induced vasospasm was positive or negative. Vasospasm positive was defined as more than 90% stenosis provoked with chest pain and/or ischemic ST change. Positive vessels were subdivided according to focal or diffuse vasospasm. These vessels were also classified into 2 other categories according to whether vasospasm in the distal artery was positive or negative. RESULTS: Coronary flow reserve was significantly lower in vessels with vasospasm than in vessels without vasospasm in patients without vasospasm(2.9 +/- 0.8 vs 3.6 +/- 1.0, p = 0.0005). Coronary flow reserve was significantly lower in vessels without vasospasm in patients with vasospasm than in vessels without vasospasm in patients without vasospasm(3.0 +/- 0.8 vs 3.6 +/- 1.0, p = 0.03). There was no significant difference in coronary flow reserve between vessels with vasospasm and vessels without vasospasm in patients with vasospasm(2.9 +/- 0.8 vs 3.0 +/- 0.8, p = 0.8). There was no significant difference in coronary flow reserve between focal and diffuse vasospasm(3.2 +/- 0.8 vs 2.9 +/- 0.8, p = 0.3). Coronary flow reserve was significantly lower in vessels with vasospasm in the distal artery than in vessels without vasospasm in the distal artery (2.8 +/- 0.8 vs 3.4 +/- 1.0, p = 0.004). CONCLUSIONS: Patients with vasospastic angina have microvascular impairment in both vessels with vasospasm, and vessels without vasospasm. Microvascular impairment is prominent in vessels with vasospasm in the distal artery.     

The predictive value of ventricular function during exercise after a myocardial infarct]

To assess the prognostic value of exercise left ventricular function, and if this test improves the prognostic value of clinical data and exercise test, 146 patients (mean age 56 +/- 9 years) underwent rest and exercise radionuclide angiography, 10 days after myocardial infarction. During follow-up (mean 16 +/- 5 months), 32 patients had new coronary events: 5 died, 9 had a new myocardial infarction and the remaining 18 developed unstable angina (Class III-IV of the CCS classification). Patients with new coronary events had more frequently severe left ventricular failure (Killip III-IV) (15% vs 3%; p less than 0.05) and postinfarction angina (32% vs 9%; p less than 0.01) than their counterparts. There were no differences regarding rest ejection fraction between both groups of patients. Exercise ejection fraction increased significantly (50 +/- 14% to 56 +/- 16%, p less than 0.001), while there was no change in patients with new coronary events (46 +/- 16% to 43 +/- 15%, NS). Logistic regression analysis including only clinical data identified postinfarction angina (p less than 0.01) and left ventricular failure (Killip III-IV) (p less than 0.01) as independent predictors of new coronary events. The sensitivity and specificity of the regression equation obtained with clinical data were 43% and 90%, respectively. Analyzing data from clinical variables, as well as exercise test and both, rest and exercise radionuclide angiography, logistic regression analysis identified, exercise ejection fraction (p less than 0.001), postinfarction angina (p less than 0.01) and rest ejection fraction (p less than 0.05) as independent predictors of new coronary events.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of coronary angioplasty on electrocardiographic changes in patients with unstable angina secondary to left anterior descending coronary artery disease

The effect of semiemergent percutaneous transluminal coronary angioplasty on clinical and electrocardiographic (ECG) variables was assessed in 76 patients with unstable angina secondary to an isolated severe proximal left anterior descending coronary artery stenosis. All patients manifested symmetric T wave inversion in two or more anterior ECG leads. Wall motion abnormalities were present in 37 patients on ventriculography before dilation. Angioplasty was successful in 70 patients (92%), resulting in a reduction in luminal diameter stenosis from 91 +/- 8% to 21 +/- 6%, with no major acute procedure-related complications observed. The other six patients underwent semiurgent (less than 48 h) coronary artery bypass surgery and three patients experienced a myocardial infarction (before bypass surgery in two). Serial ECGs revealed complete resolution of ST-T wave changes in 51% of patients at 14 weeks and in 90% at 28 weeks. In contrast, prolongation of the corrected QT interval, which was present in 16 patients (8%), normalized within 48 h of successful angioplasty. Twelve of these 16 patients with a prolonged QT interval had nonocclusive thrombus formation and poor collateral circulation on angiography. Patients were followed up for 6 to 43 months (mean 23 +/- 10). Angiographic evidence of restenosis was present in 34% of patients, all of whom underwent a successful second or third procedure. One death occurred at 8 months after successful angioplasty. Wall motion abnormalities had completely resolved in 13 of 15 patients who underwent repeat ventriculography, at which time 10 had a normal ECG. This study demonstrates that ECG changes may persist for up to 7 months in patients who undergo successful angioplasty for severe left anterior descending coronary artery disease and unstable angina. Semiemergent angioplasty was associated with a high initial success rate and excellent long-term outcome.     

Quantification of myocardium at risk in unstable angina: comparison of patients with and without previous infarction

We studied two subgroups of patients with unstable angina pectoris: 35 without (Group A) and 73 with (Group B) previous myocardial infarction. The severity of coronary artery disease was assessed by means of a previously described scoring system. This scoring system was used to calculate the proportion of left ventricular myocardium fed by significantly (greater than 75% luminal area reduction) stenosed coronary arteries (called percent myocardium threatened). To estimate the amount of myocardium lost by previous infarction we used a four-point wall motion score for each of seven left ventricular wall segments: a value of 2 was given to normokinetic segments, 1 for hypokinetic segments, 0 for akinetic and -1 for dyskinetic segments. The deficit in wall motion score was used to estimate the amount of myocardium infarcted. This was then subtracted from the proportion of myocardium threatened to yield the proportion of myocardium still in jeopardy. We found a different extent and severity of coronary artery disease between the two subgroups. In the group without previous infarction, the numbers of patients with one-, two- and three-vessel disease were 15, 9, and 11, respectively (or 43, 26, and 31%). In those with a previous infarction, the respective numbers were 11, 23, and 39 (or 15, 31.5, and 53.5%). This difference is statistically significant (P less than 0.01). The mean number of stenotic arteries was 1.9 +/- 0.9 in the patients without previous infarction and 2.4 +/- 0.7 in those with an infarction (P less than 0.05). Using the above-mentioned scoring system the score was 3.2 +/- 1.4 in patients without previous infarction and 4.0 +/- 1.6 in those with previous infarction (P less than 0.05). The percent myocardium threatened was 53.6 +/- 24.1 vs. 68.7 +/- 24.7 (P less than 0.01). Wall motion score was 13.8 +/- 0.6 in Group A and 10.6 +/- 3.1 in Group B (P less than 0.01), which gives values for the proportion of myocardium infarcted of 1.6 +/- 4.2 and 24.2 +/- 22.0%, respectively. The percentage still in jeopardy (after subtracting that infarcted from that threatened) was 51.8 +/- 22.7 in those without and 44.2 +/- 31.1 in those with a previous infarction: this difference is not statistically significant. We conclude that patients with unstable angina pectoris who have sustained a previous myocardial infarction have more severe coronary artery disease than similar patients without previous infarction. The amount of left ventricular myocardium still in jeopardy of becoming infarcted is, however, the same.     

Left ventricular function after myocardial infarction: clinical and angiographic correlations

There is a paucity of information correlating the angiographic findings immediately after myocardial infarction with the clinical status before infarction. Therefore, the coronary anatomy, collateral circulation and quantitative left ventricular function were studied in 39 patients who underwent angiography within 3 weeks of a first transmural myocardial infarction. In all patients, the vessel supplying the infarct was totally occluded at the time of angiography. Patients without angina before infarction (Group I) had fewer coronary obstructions than did patients with a long history of angina before infarction (Group II) (1.5 +/- 0.5 versus 2.5 +/- 0.5, respectively, p less than 0.001) but worse overall and regional left ventricular function. These paradoxical differences between Groups I and II were evident in patients with anterior as well as inferior infarction. Patients in Group I had significantly lower collateral scores than did patients in Group II (0.6 +/- 0.8 versus 1.9 +/- 0.9, respectively, p less than 0.0001) and 13 of 22 patients in Group I had no collateral vessels compared with only 1 of 17 in Group II (p less than 0.001). Partial preservation of anterior wall function in Group II patients with anterior infarction was related both to the presence of collateral vessels and to the more distal obstruction of the left anterior descending coronary artery in these patients as compared with patients with anterior infarction in Group I. In contrast, in patients with inferior wall infarction, no relation could be found between the presence of collateral vessels and regional left ventricular function, although only two patients in this series with inferior infarction did not have collateral vessels.(ABSTRACT TRUNCATED AT 250 WORDS)