Simultaneous multivessel coronary artery spasm demonstrated by quantitative analysis of thallium-201 single photon emission computed tomography

Non-invasive diagnosis of vasospastic angina

Vasospastic angina (VSA), or variant angina, is an under-recognized cause of chest pain and myocardial infarction, especially in Western countries. VSA leads to a declined quality of life and is associated with increased morbidity and mortality. Currently, the diagnosis of VSA relies on invasive testing that requires the direct intracoronary administration of ergonovine or acetylcholine. However, invasive vasoreactivity testing is underutilized. Several non-invasive imaging alternatives have been proposed to screen for VSA. This review aims to discuss the strengths and limitations of available non-invasive imaging tests for vasospastic angina.

Clinical Characteristics and Prognosis of Patients with Multi-Vessel Coronary Spasm in Comparison with Those in Patients with Single-Vessel Coronary Spasm

(1) Background: We have sometimes experienced patients with vasospastic angina (VSA) who presented multi-vessel spasm (MVS) on coronary angiography and spasm provocation test (SPT). However, the clinical characteristics of VSA patients with MVS and the prognosis of such patients in the clinical setting have not been clarified. Therefore, we compared the clinical characteristics and prognosis in VSA patients with MVS with those in VSA patients with single-vessel spasm (SVS). (2) Methods: A total of 152 patients (mean age, 67 years, 74 men and 78 women) with VSA, in which the presence of coronary spasm was assessed in both left coronary artery (LCA) and right coronary artery (RCA) on SPT, were enrolled. We defined VSA as the presence of >90% narrowing of the epicardial coronary artery on angiograms, accompanied by usual chest symptoms and/or ischaemic ST-T changes on the electrocardiogram. On SPT, MVS was defined as the presence of spasms on ≥2 major coronary arteries. Based on the presence of MVS, patients were divided into the MVS group and the SVS group. The frequencies of conventional coronary risk factors, blood chemical parameters, average times of anginal attack, SPT findings such as spasm provocation induced by a low dose of acetylcholine (L-ACh) and total occlusion due to coronary spasm (TOC), number of coronary vasodilators at discharge and major cardiovascular events (MACE, including cardiac death and readmission due to any cause of cardiovascular diseases) were compared between the two groups. (3) Results: The MVS and SVS groups were comprised of 98 (64%) and 54 (36%) patients, respectively. The level of fasting blood glucose (FBS) was lower (p < 0.01), and the level of cystatin-C (n = 89) tended to be higher (p = 0.07) in the MVS group than in the SVS group. The frequencies of L-ACh-induced coronary spasm (33% in MVS and 17% in SVS, p = 0.04) and TOC (12% in MVS, 0% in SVS, p < 0.01) were higher in the MVS group than in the SVS group. The average number of coronary vasodilators at discharge was higher in the MVS group (1.2 ± 0.4) than in the SVS group (0.9 ± 0.5, p < 0.01). The frequency of MACE was not different between the two groups. (4) Conclusions: Patients with MVS may have higher VSA activity on SPT and have more aggressive medications, leading to a comparable prognosis in VSA patients with SVS. MVS is an important indicator of at least VSA activity, and cardiologists should confirm this in SPT whenever possible. Further studies should confirm whether lower FBS levels and higher cystatin-C levels are any markers of MVS.

Clinical usefulness of myocardial scintigraphy in patients with vasospastic angina

BACKGROUND

Myocardial scintigraphy is defined as class IIb in the Japanese Circulation Society guideline for diagnosis of vasospastic angina (VSA). However, Caucasian guidelines had no classification of cardiac scintigraphy for diagnosis of VSA.

OBJECTIVES

To clarify the clinical usefulness of myocardial scintigraphy, we analyzed the sensitivity and specificity of each cardiac scintigraphy.

METHODS

We extracted the 136 papers of myocardial scintigraphy from the PubMed database from 1980 to 2018 in patients with VSA. Finally we analyzed the 88 papers including 33 papers of^201-thallium (Tl), 10 papers of ¹²³I beta-methyl 15-para-iodophenyl 3(R, S)-methylpentadecanoic acid (BMIPP), 9 papers of ¹²³I-metaiodobenzylguanidine (MIBG), 4 papers of ^99mTc-sestamibi (MIBI: methoxy-isobutyl-isonitrile), and 2 papers of tetrofosmin to investigate the sensitivity and specificity of each tracer.

RESULTS

Tl, BMIPP, or MIBG cardiac scintigraphy were useful to diagnose patients with VSA, because sensitivity was 57-73%. Specificity was 55-83%. Sensitivity of left circumflex artery was significantly lower than other vessels. BMIPP imaging may be helpful for clinical course of VSA. However, myocardial scintigraphic abnormal findings may not always show the ischemic memory due to coronary artery spasm.

CONCLUSIONS

Recent cardiologists do not perform hyperventilation tests or MIBG scintigraphy for diagnosis of coronary spasm. After understanding the flow of the times, cardiologists should use Tl or BMIPP myocardial scintigraphy for VSA as one of supplementary tools in the real world.

Effect of coronary artery spasm on long-term outcomes in survivors of acute myocardial infarction

BACKGROUND

The prevalence of coronary artery spasm (CAS) inducible by intracoronary injection of acetylcholine (ACh) is high in survivors of acute myocardial infarction (AMI). Although there is a potential risk of sudden cardiac death in patients with CAS, the prognostic value of CAS was not clear. Thus, this study examined the effect of CAS on long-term prognosis in survivors of AMI in a prospective manner.

METHODS

The study included a total of 437 patients with AMI who underwent a CAS provocation test using ACh. All patients were followed prospectively for 5years or until the occurrence of the primary composite endpoint that consisted of cardiac death and acute coronary syndrome (ACS).

RESULTS

CAS was induced in 195 (45%) of the study patients. During the follow-up period, 30 patients had a recurrent event (4 had cardiac death and 26 had ACS). Kaplan-Meier estimates in time-to-first-event analysis demonstrated a similar probability of the primary endpoint in patients with and without inducible CAS (p=0.13, log-rank test). The rate of each component of the composite endpoint was also comparable between the 2 patient groups. In Cox proportional hazards risk analysis, treatment with calcium channel blockers (CCBs) negatively predicted the primary endpoints in patients with inducible CAS (HR, 0.21; 95% CI, 0.08-0.55, p<0.01).

CONCLUSIONS

The presence of inducible CAS did not increase the incidence of the cardiac events in AMI survivors. Treatment with CCBs may improve outcomes in AMI survivors with inducible CAS.

CLINICAL TRIAL REGISTRATION

URL: https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000021340, unique identifier: UMIN000018432.

Coronary vasospasm produces reversible perfusion defects observed during adenosine triphosphate stress myocardial single-photon emission computed tomography

BACKGROUND

Adenosine triphosphate stress thallium-201 single-photon emission computed tomography (ATP-SPECT) is useful for diagnosing coronary artery disease (CAD), although sometimes false positive results are observed. It has not been established whether a coronary spasm is responsible for the false positive findings during ATP-SPECT.

HYPOTHESIS

We investigated whether coronary spasm is one of the factors which produces reversible defects on ATP-SPECT.

METHODS

Eighty-six patients (mean age: 62 y; 58 men) who underwent both spasm-provocation testing by coronary angiography and ATP-SPECT, were selected for the study. Patients with coronary narrowing (>30%), myocardial infarction, or heart failure were excluded. Patients were divided into 2 groups based on whether the spasm-provocation test result was positive (vasospastic angina [VSA] group, n = 46) or negative (non-VSA group, n = 39).

RESULTS

The body mass index was lower in the VSA group than in the non-VSA group (p = 0.005). On ATP-SPECT imaging, any type of reversible defect was observed more frequently in the VSA group (68%) than in the non-VSA group (36%, p = 0.0027). Logistic regression analysis demonstrated that the presence of reversible defects was one of the factors accounting for the presence of coronary vasospasm (p = 0.0022, R2 = 0.172).

CONCLUSIONS

The findings suggest that reversible defects on ATP-SPECT imaging are frequently present in patients with coronary vasospasm. Coronary spasm may be considered as 1 of the factors, which produce reversible defects on ATP-SPECT, observed in patients with chest symptoms and angiographically normal coronary arteries.

Simultaneous multivessel coronary spasm causing acute myocardial infarction: a case report

Spontaneous simultaneous multivessel coronary artery spasm in patients with acute myocardial infarction (AMI) is uncommon. A 79-year-old Japanese man was transferred to this hospital because of severe prolonged chest pain and faintness. Left coronary angiography revealed total occlusion of the left anterior descending and the left circumflex coronary arteries. Moreover, right coronary angiography revealed 99% stenosis of the right coronary artery. After intracoronary administration of nicorandil, left coronary artery and right coronary artery angiography revealed no organic stenosis or thrombus. This is the first report in which simultaneous 3-vessel spasm was documented by emergency angiography in AMI.

A case of multivessel coronary artery spasm resulting in wandering ST segment elevation

We describe a case of recurrent episodes of resting myocardial ischaemia associated with ST elevation on ECG in different territories. Multivessel coronary artery spasm was demonstrated that was reversed with intracoronary glycerine trinitrate.

Prognostic Value of I-123 Metaiodobenzylguanidine Imaging in Vasospastic Angina Without Significant Coronary Stenosis

BACKGROUND

Myocardial imaging is widely used to detect coronary artery disease and to assess its prognosis. In vasospastic angina (VA), cardiac imaging can provide information on disease activity, which is related to cardiac events. The aim of this study was to clarify whether exercise thallium-201 imaging (Tl-SPECT) and 123I-metaiodobenzylguanidine imaging (MIBG) have prognostic value for patients with VA, but without significant coronary artery stenosis.

METHODS AND RESULTS

One hundred and 5 patients who showed acetylcholine-induced coronary spasm, normal left ventricular function and no significant stenosis (<50%) underwent both symptom-limited Tl-SPECT and MIBG within 1 month. All patients were prescribed calcium antagonist during the follow-up period (mean 4.7 years). Exercise-induced ischemia was detected by Tl-SPECT in 53 patients and multivessel coronary spasm by coronary angiography in 33 patients. During the follow-up period, 1 patient died suddenly and another died of acute myocardial infarction (MI). Two patients developed nonfatal acute MI and 7 patients underwent emergency coronary angiography because of unstable angina. According to the baseline characteristics, VA with cardiac events showed a significantly higher heart-to-mediastinum ratio (H/M ratio) and a significantly lower MIBG washout rate than those without cardiac events (p<0.03 and p<0.02, respectively). Among 8 clinical variables, including coronary risk factors, exercise parameters and exercise-induced ischemia on Tl-SPECT and the MIBG delayed H/M ratio and washout rate, univariate Cox proportional hazard regression analysis showed that the high H/M ratio and reduced washout rate of MIBG were significant predictors of future cardiac events (relative risk (RR) =4, confidence interval (CI) =1.21-13.29, p<0.02 for H/M ratio and RR 0.92, CI 0.85-0.99, p<0.02 for washout rate). However, exercise-induced ischemia did not show any statistical significance. By multivariate Cox proportional hazard regression analysis, a reduced MIBG washout rate was the only significant predictor of future cardiac events (odds ratio =0.90, CI =0.82-1.00, p<0.04).

CONCLUSION

MIBG imaging can identify high-risk patients, even among those with VA who were previously regarded as low risk. This result strongly supports the idea that cardiac sympathetic dysfunction contributes to coronary artery spasm leading to cardiac events.

Diagnosis of multivessel coronary vasospasm by detecting postischemic regional left ventricular delayed relaxation on echocardiography using color kinesis

BACKGROUND

It is not known whether multivessel coronary spasm occurs spontaneously in patients who have variant angina (VA) with demonstrated multivessel spasm induced by intracoronary injection of acetylcholine (ACh). Regional left ventricular (LV) diastolic dysfunction or wall motion abnormality may persist after an episode of coronary vasospasm. Color kinesis (CK) is a recent development that facilitates the echocardiographic evaluation of regional diastolic wall motion.

METHODS AND RESULTS

Regional diastolic wall motion was evaluated using CK in 26 patients with VA within 1 week of the last episode of angina. The LV segmental filling fraction in the short-axis view during the first 30% of the diastolic filling time, expressed as a percentage, was used to objectively identify postischemic diastolic endocardial motion asynchrony. Diastolic asynchrony or regional LV delayed relaxation was noted in all 26 (100%) patients and in 14 (54%) it was detected in multiple vascular territories, suggesting multivessel spasm. Multivessel spasm was induced by ACh in 11 (79%) of the patients with suspected multivessel spasm by CK. In 11 (92%) of the 12 patients with multivessel spasm induced by ACh multiple regions of delayed relaxation had been noted by CK. The regions of delayed relaxation were largely consistent with the territories perfused by the arteries reacting to ACh (sensitivity: 96%, specificity: 91%).

CONCLUSION

ACh induced spasm in the same coronary arteries as those perfusing the regions with delayed diastolic wall motion detected by CK in most of the patients with VA, suggesting that multivessel spasm does occur spontaneously in patients with susceptible arteries.

Clandestine ischemia in patients with vasospastic angina

BACKGROUND

Coronary vasospasms generally occur at rest, but can also be triggered by physical exercise. Anginal pain and ST-segment elevation may be seen during exercise-stress tests. ST-segment depression, due to nonocclusive vasospasms, has also been found to occur. When the result of a test is positive, scintigraphy usually reveals perfusion defects. True silent or clandestine ischemia (normal result of exercise test with perfusion defects) in these patients is very uncommon.

OBJECTIVE

To stress the need for suspecting occurrence of coronary vasospasms in order to perform a proper diagnosis.

METHODS

Eight patients with angina were selected for this study. They had negative results of exercise tests with perfusion defects detected by thallium-201 tomography, normal coronary arteries and vasospasms. Maximal exercise-stress tests with thallium-201 tomography were performed. Sizes of perfusion defects were quantified by examining polar maps. Coronary angiography and then an intracoronary ergonovine test were performed for each patient.

RESULTS

Significant defects were seen in territory of the right coronary artery, the left anterior descending artery, or both. Lung:heart ratio was normal in every case. The coronary arteries were normal and vasospasms were elicited with ergonovine in all the patients. Correspondence between the location of perfusion defects and angiographic spasms was generally observed. After treatment with calcium antagonists and nitrates all of them improved and defects detected by thallium tomography were no longer found when tests were repeated.

CONCLUSIONS

Some patients with vasospastic angina may have normal results of exercise-stress tests and reversible perfusion defects detectable by scintigraphy. This finding must lead one to perform coronary angiography without administration of nitroglycerine beforehand and an ergonovine test if the coronary arteries are normal.

Dipyridamole-induced reversible thallium-201 defect in patients with vasospastic angina and nearly normal coronary arteries

BACKGROUND

Dipyridamole is a vasodilator of resistance vessels and has no vasoconstrictive effect on large coronary arteries.

HYPOTHESIS

The present study used dipyridamole thallium-201 (201Tl) scintigraphy to clarify the role of microvasculature in coronary flow limitation in patients with vasospastic angina and normal coronary arteries.

METHODS

Sixteen patients underwent dipyridamole and exercise 201Tl scintigraphy and provocative coronary angiography with acetylcholine. All patients showed coronary spasm (> 90% vasoconstriction concomitant with ST change) in at least one vessel.

RESULTS

Dipyridamole or exercise caused only ST depression despite the ST elevation observed at spontaneous attack. Dipyridamole 201Tl scintigraphy demonstrated the reversible defects (11 cases), as did exercise 201Tl scintigraphy (13 cases). The region of 201Tl defect was not always consistent with the territories of angiographically depicted vasospastic arteries. Basal coronary tone, assessed by percentage of diameter change of epicardial arteries from baseline to isosorbide dinitrate administration, did not differ between the positive and the negative defect regions.

CONCLUSION

These results support the hypothesis that, in addition to epicardial coronary spasm, the dysfunction of microvasculature is responsible for abnormal coronary perfusion in the subgroup of patients with vasospastic angina and normal coronary arteries.

Hyperventilation as a specific test for diagnosis of coronary artery spasm

The hyperventilation test has been used as a clinical tool to induce coronary spasm. However, its diagnostic and prognostic values have not been fully elucidated. This study was designed to establish the sensitivity and specificity of the hyperventilation test and to clarify the characteristics of hyperventilation test-positive patients. We examined 206 patients in whom coronary spasm was documented by angiography (spasm group), and 183 patients without angina at rest in whom acetylcholine failed to induce spasm (nonspasm group). All patients performed vigorous hyperventilation for 6 minutes in the early morning. Of the spasm group patients, 127 showed positive responses to the test, including ST elevation (n = 111), ST depression (n = 15) and negative U wave (n = 1). None in the nonspasm group showed any ischemic electrocardiographic change. Thus, the sensitivity and specificity of this test for diagnosis of coronary spasm were 62% and 100%, respectively. In the spasm group, there were no significant differences between hyperventilation test-positive and test-negative patients in age, sex, the prevalence of hypertension, diabetes mellitus, obesity, smoking, and the number of diseased vessels. When clinical characteristics were compared, the proportions of the patients with high disease activity (> or =5 attacks a week), with severe arrhythmias (second- or third-degree atrioventricular block and/or ventricular tachycardia) during attacks, and with multivessel spasm were significantly higher in the hyperventilation test-positive patients than in the negative patients (69% vs 20%, p <0.0001; 31% vs 11%, p <0.005; and 58% vs 34%, p <0.01, respectively). These findings imply that hyperventilation is a highly specific test for the diagnosis of coronary artery spasm, and that hyperventilation test-positive patients are likely to have life-threatening arrhythmias during attacks and multivessel spasm.

Long-lasting abnormalities in cardiac sympathetic nervous system in patients with coronary spastic angina: quantitative analysis with iodine 123 metaiodobenzylguanidine myocardial scintigraphy

Quantitative analysis of iodine 123 metaiodobenzylguanidine (MIBG) myocardial tomographic imaging showed that the regional uptake reduction and abnormally high washout of MIBG in the myocardial territories of the coronary artery with spasm were observed in 33 (75%) and in 30 (68%) of 44 patients with coronary spastic angina, whereas it was observed in two (7%) and in four (15%) of 27 control subjects, respectively. The patients with higher disease activity of the anginal attack and those with life-threatening ventricular arrhythmias were frequently associated with either the uptake reduction or the abnormally high washout of MIBG (91% in patients with high disease activity, 100% in patients with ventricular arrhythmias). The repeated studies of MIBG myocardial tomographic imaging at 2 and 6 months after suppression of anginal attacks by medical treatments showed that the scintigraphic abnormalities still remained in 85% of the patients at 2 months and 32% at 6 months. Thus the abnormalities in sympathetic nervous system assessed with MIBG scintigraphy has been shown to be highly associated with patients with coronary arteries with spasm, particularly high-risk patients, and lasted for several months despite suppression of anginal attack.

Assessment of regional sympathetic nerve activity in vasospastic angina: analysis of iodine 123-labeled metaiodobenzylguanidine scintigraphy

With the use of iodine 123-labeled metaiodobenzylguanidine (123I-MIBG) scintigraphy, this study evaluated regional sympathetic nerve activity in vasospastic angina. Twenty male patients with left anterior descending coronary artery spasm and 18 male patients with normal coronary arteries as a control group were studied. All patients underwent quantitative 123I-MIBG scintigraphy and atropine stress 123I-MIBG scintigraphy. Both groups showed a similar heterogeneous 123I-MIBG uptake in the left ventricle. However, the regional washout rate in patients with coronary artery spasm was significantly reduced in all three territories compared with that in the control group. In vasospastic angina, the regional washout rate in the left anterior descending coronary artery territory was significantly reduced as compared with the other two regions. After intravenous injection of 1 mg atropine, the regional washout rate in the three regions significantly increased in both groups, but the regional differences between the two groups disappeared. The current study demonstrated that cardiac sympathetic nerve activity in vasospastic angina was suppressed, especially in the territory of the spasm-induced coronary artery, probably because of the enhanced parasympathetic nerve activity.

Role of adenosine in pathogenesis of syndrome X: assessment with coronary hemodynamic measurements and thallium-201 myocardial single-photon emission computed tomography

OBJECTIVES

This study was performed 1) to examine the role of adenosine in the pathogenesis of syndrome X in patients with this syndrome and abnormal results on myocardial scintigrams during exercise, and 2) to determine the susceptibility to myocardial ischemia in this subset of patients with syndrome X.

BACKGROUND

A role for adenosine in the pathogenesis of syndrome X has recently been postulated, but there are few clinical data supporting this hypothesis.

METHODS

Exercise thallium-201 myocardial scintigraphy after intravenous administration of aminophylline, an adenosine receptor blocking agent, or saline solution and adenosine thallium-201 scintigraphy were performed in 26 patients with syndrome X. Hemodynamic variables during exercise and perfusion defect size after aminophylline and saline infusions were compared. At cardiac catheterization, coronary hemodynamic variables during separate infusions of adenosine and doubutamine were also examined and were compared among patients with abnormal or normal scintigrams and 10 control subjects.

RESULTS

Perfusion abnormalities on exercise-thallium-201 scintigraphy occurred in 14 of 26 patients with syndrome X. Intravenous infusion of aminophylline suppressed the scintigraphic perfusion defect and prolonged the time to 1-mm ST segment depression in patients with syndrome X with abnormal exercise scintigrams. Intravenous infusion of adenosine induced a perfusion defect in the same myocardial area where the perfusion defect was observed at exercise in 7 of the 14 patients with syndrome X. At cardiac catheterization, patients with syndrome X with abnormal exercise scintigrams had lower coronary flow reserve and a greater frequency of myocardial lactate production and ST segment depression in response to the infusions of adenosine and doubtamine than did the other two groups. During adenosine infusion, great cardiac vein blood flow and oxygen content were significantly increased and myocardial oxygen consumption and lactate extraction were significantly reduced from baseline without a significant increase in rate-pressure product in this subset of patients with syndrome X.

CONCLUSIONS

Patients with syndrome X with abnormal exercise scintigrams have high susceptibility to myocardial ischemia during exercise or pharmacologic stress tests, probably owing to reduced coronary flow reserve. A heterogeneous response to endogenous adenosine may contribute to scintigraphic perfusion abnormalities and myocardial ischemia during exercise in this subset of patients with syndrome X.

Tl-201 scintigraphy in multivessel exercise-induced variant angina

A 53-year-old man presented for evaluation of nocturnal chest pain, consistent with angina pectoris. An exercise stress test reproduced his symptoms, however, exercise electrocardiograms were nondiagnostic. An exercise-thallium perfusion study confirmed vasospasm as the cause. This knowledge guided subsequent successful medical therapy.

Increased plasma levels of B-type natriuretic peptide in patients with unstable angina

This study was designed to examine the plasma levels of B-type or brain natriuretic peptide (BNP), as well as A-type or atrial natriuretic peptide (ANP) in patients with unstable angina as compared with those in patients with stable exertional angina and control subjects. We measured the plasma levels of BNP and ANP in 33 patients with unstable angina, 20 patients with stable exertional angina, and 20 control subjects. The plasma levels of BNP were significantly increased in patients with unstable angina compared with those in patients with stable exertional angina and control subjects, respectively (39.5 +/- 29.4 pg/ml vs 15.1 +/- 8.0 pg/ml; p < 0.01 and 39.5 +/- 29.4 pg/ml vs 10.3 +/- 6.4 pg/ml; p < 0.01, respectively). On the other hand, there was no significant difference in the plasma levels of ANP among the three groups. Furthermore, in patients with unstable angina, the plasma levels of BNP decreased significantly after the medical treatment (from 39.5 +/- 29.4 pg/ml to 15.8 +/- 11.0 pg/ ml; p < 0.01), whereas the plasma levels of ANP did not change. We conclude that the plasma levels of BNP are increased in the majority of patients with unstable angina and that the increased levels decrease toward normal after treatment.

Characteristics of vasospastic angina with exercised-induced ischemia--analysis of parameters of hemostasis and fibrinolysis

To characterize the vasospastic angina patients with exercise-induced ischemia, we measured hemostasis (platelet factor 4; PF4, fibrinopeptide A; FPA) and fibrinolytic parameters (tissue plasminogen activator antigen; t-PA, free plasminogen activator inhibitor-1 antigen; free PAI-1) in 15 normal subjects and 33 vasospastic angina patients without significant coronary artery stenosis (less than 50% stenosis). All of the vasospastic angina patients began to feel chest pain within 3 months before diagnostic coronary angiography. Blood samples were obtained from all of the study patients at 8:30-9:30 am before exercise 201Tl emission computed tomography. Vasospastic angina patients were divided into 2 groups; 15 patients with exercise-induced ischemia (group 1) and 18 patients without exercise-induced ischemia (group 2). On coronary angiography, the severity of coronary artery stenosis at the site of spasm in group 1 (34 +/- 5%) was greater than that in group 2 (18 +/- 3%). Plasma FPA and PF 4 levels in group 1 were also significantly higher than those in normal subjects and group 2. Plasma t-PA and free PAI-1 levels in group 1 were significantly higher than those in normal subjects and group 2. Plasma levels of free PAI-1 group 2 were also significantly higher than those in normal subjects. The present study demonstrated that all of the patients with vasospastic angina had impaired fibrinolysis, and these patients with exercise-induced ischemia showed enhanced platelet activation, an enhanced coagulation system, and advanced atherosclerotic lesions. These results suggest that vasospastic angina with exercise-induced ischemia puts patients at increased risk for thrombus formation.

Heart period variability in patients with variant angina

To clarify how cardiac autonomic control is affected in variant angina, we analyzed heart period variability in 35 patients with variant angina and in 19 control subjects. Patients with variant angina were divided into 1-vessel (group S, n = 17) and multivessel spasm groups (group M, n = 18) according to the site(s) of ST elevation on the electrocardiogram during attacks. The 24-hour Holter electrocardiogram recorded 6 +/- 3 days after the treatment with calcium antagonist was analyzed to avoid the possible influence of spontaneous attacks. In 5 group M patients, the electrocardiogram recorded 1 month after the treatment was also analyzed. There was no difference in the number of spontaneous attacks between groups S and M. The standard deviation of all normal RR intervals (SDNN) and the percentage of differences between adjacent normal RR intervals >50 (pNN50) in variant angina were slightly but significantly lower than those in controls. There were no differences in other indexes between variant angina and controls. When the data were analyzed separately in groups S and M, averaged RR intervals (MN), SDNN, pNN50, high-frequency power, and low-frequency power in group M were significantly lower than those in group S and controls, and the ratio of low- to high-frequency power in group M was significantly higher than that in group S and controls. There was no difference in any index between group S and controls. All abnormal indexes in group M recovered to levels similar to those in controls 1 month after the treatment. In conclusion, depressed cardiac vagal control and sympathetic-dominant sympathovagal interaction were present in patients with variant angina, especially in those with multivessel spasm.

Increased constrictor response to acetylcholine of the isolated coronary arteries from patients with variant angina

The aim of this study was to determine whether isolated coronary arteries from patients with variant angina show hyperreactivity and/or supersensitivity to acetylcholine in vitro. Coronary arterial rings were obtained at autopsy within 3 h after death from six coronary arteries having spasm in four patients with variant angina and from 22 coronary arteries in 14 control patients with non-cardiac death. The coronary rings were suspended in the organ chamber filled with Krebs Henseleit solution bubbled with 95% O2 + 5% CO2, and their isometric tensions were monitored. Arterial rings isolated from both the patients with variant angina and the controls contracted dose-dependently in response to acetylcholine (10(-9)-10(-5) mol/l). EC50 of acetylcholine (i.e. concentration producing 50% of maximum contraction) was not significantly different between the coronary arteries from patients with variant angina and those from controls, but maximum contraction elicited by acetylcholine (expressed as a percentage of the contraction elicited by 60 mmol/l KCl) was significantly greater in the coronary arteries from patients with variant angina than those from controls. In conclusion, the isolated coronary arteries from patients with variant angina have hypercontractile reactivity to acetylcholine. This intrinsic alteration of the coronary reactivity to acetylcholine may play a role in the genesis of coronary spasm occurring in the situations of enhanced parasympathetic nervous discharge.

Comparison of the distribution of myocardial blood flow between exercise-induced and hyperventilation-induced attacks of coronary spasm: a study with thallium-201 myocardial scintigraphy

Exercise and hyperventilation tests are often used as the provocative tests for coronary artery spasm. To examine the distribution of myocardial blood flow during exercise-induced and hyperventilation-induced attacks of coronary spasm, thallium-201 myocardial scintigraphy was performed in 47 patients with variant angina. The extent and severity scores and severity index (severity score/extent score) of scintigraphic perfusion defect were calculated. In 32 patients, anginal attack associated with ST elevation on the electrocardiogram was induced by exercise; in 23 patients, the attack was induced by hyperventilation. In patients with either anterior or inferior wall ischemia, both the extent and severity scores and severity index in the scintigram were significantly greater in exercise-induced anginal attack than those in hyperventilation-induced attack. In patients with simultaneous anterior and inferior wall ischemia, they tended to be greater in exercise-induced attack. In eight patients in whom anginal attack was induced by both exercise and hyperventilation, these scores and index were significantly greater in exercise-induced attack than those in hyperventilation-induced attack. These data suggest that myocardial ischemia during exercise-induced attack is enhanced as compared with that during hyperventilation-induced attack. Thallium-201 scintigraphy combined with exercise testing seems to be more sensitive for detecting myocardial ischemia induced by coronary spasm.

Influence of exercise-induced coronary artery spasm on thallium-201 initial distribution and washout kinetics in patients with variant and classic angina pectoris

Thallium-201 single-photon emission computed tomography was performed immediately, and 2 and 4 hours after exercise-induced anginal attack in 2 groups of patients with either exercise-induced coronary spasm or severe fixed stenosis on the isolated proximal left anterior descending coronary artery. All patients with variant angina had transient ST-segment elevation during the exercise-induced attack for thallium-201 scintigraphic study. Both perfusion defects and 4-hour washout abnormalities were significantly greater in patients with variant angina than in those with stable effort angina (p < 0.01). In patients with stable effort angina, thallium-201 activity in ischemic regions (as a percentage of initial count in the normal region) progressively decreased, whereas in patients with variant angina it increased from 38% (initial) to 48% (2 hours), and then declined to 42% (4 hours). The initial normalized thallium-201 activity in the ischemic regions was significantly lower in patients with variant angina than in those with stable effort angina (p < 0.001). In conclusion, perfusion and washout abnormalities during exercise-induced angina are greater in patients with variant angina than in those with stable effort angina. Exercise-induced coronary spasm seems to contribute to the profound reduction in initial thallium-201 distribution and delayed thallium-201 accumulation in the ischemic region.

Therapeutic significance of exercise-induced ST-segment elevation in patients without previous myocardial infarction

Twelve patients with exercise-induced ST-segment elevation without prior myocardial infarction, electrocardiographic evidence of left ventricular hypertrophy or left bundle branch block underwent thallium-201 tomography immediately after exercise and 4 hours later. Coronary angiography and left ventriculography were performed within an average of 8 days of exercise testing. Five patients had repeat exercise thallium-201 tomography after medical therapy or revascularization. All patients had large, reversible perfusion defects (average defect size 33.5 +/- 13%), with 11 of 12 patients having a > or = 25% stress perfusion defect. In 10 patients with atherosclerotic coronary artery disease, the average stenosis of the involved vessel was 93 +/- 9% (range 70 to 100). The electrocardiographic leads with ST-segment elevation predicted the site of reversible hypoperfusion. Two patients had extensive, reversible anterior hypoperfusion due to exercise-induced spasm of minimally stenosed left anterior descending coronary arteries. Follow-up exercise testing in 5 patients showed abolition of reversible hypoperfusion and ST changes after medical therapy or revascularization. In patients without prior myocardial infarction, exercise-induced ST-segment elevation signifies extensive, reversible hypoperfusion that can be abolished by revascularization in patients with critical coronary stenoses and by medical therapy in those with coronary vasospasm.

Plasma plasminogen activator inhibitor activity and tissue plasminogen activator levels in patients with unstable angina and those with coronary spastic angina

Plasminogen activator inhibitor (PAI) activity and tissue plasminogen activator (TPA) antigen were measured in venous samples in 14 patients with unstable angina consisting of eight patients with organic stenosed coronary arteries and six patients with coronary spastic angina (unstable angina group); in 14 patients with stable exertional angina (stable exertional angina group); and in 14 patients with chest pain syndrome (chest pain syndrome group). The plasma levels of PAI activity were higher (p less than 0.01) in the unstable angina group than in the stable exertional angina group and the chest pain syndrome group (12.3 +/- 1.0 versus 5.1 +/- 0.7 and 4.8 +/- 0.6 IU/ml). The plasma levels of TPA antigen were also higher (p less than 0.05) in the unstable angina group than in the stable exertional angina group and the chest pain syndrome group (10.2 +/- 1.3 versus 6.5 +/- 0.8 and 6.0 +/- 0.7 ng/ml). There were no significant differences in PAI activity and TPA antigen levels between the stable exertional angina group and the chest pain syndrome group. Furthermore, both PAI activity and TPA antigen levels in the unstable angina group decreased to the levels in the stable exertional angina group and the chest pain syndrome group after treatment (p less than 0.01). In conclusion, the increased plasma PAI activity in patients with unstable angina and in those with coronary spastic angina indicates that the fibrinolytic system is impaired in these patients.

Plasma platelet-derived growth factor levels in coronary circulation in unstable angina pectoris

To examine whether plasma platelet-derived growth factor (PDGF) levels are elevated in the coronary circulation of patients with unstable angina, the plasma PDGF levels in the coronary sinus and aortic root were simultaneously examined in 14 patients with unstable angina, 15 with stable exertional angina, and 15 control subjects. The mean plasma PDGF level (pg/ml) in the coronary sinus was significantly higher (p less than 0.01) in patients with unstable angina than in those with stable exertional angina and in control subjects (502.1 +/- 98.7 vs 301.3 +/- 62.5, and 312.7 +/- 62.6). However, there were no significant differences in mean plasma PDGF levels in the aortic root among the 3 groups. It is concluded that PDGF release is increased in the coronary circulation in patients with unstable angina.

A new strategy for the reduction of acute myocardial infarction in variant angina

To study the effects of stepwise early treatment in variant angina pectoris, frequencies of cardiac events and complications were examined after three different types of treatment. The subjects of the study consisted of 159 consecutive patients with variant angina pectoris, who were in need of hospitalization. The three treatment modalities were the introduction of calcium antagonists, nicorandil and nitroglycerin infusion, and percutaneous transluminal coronary angioplasty (PTCA), respectively. The cardiac event rate for this series of patients was 16% (25 of 159). The cumulative cardiac event rate was 22% at 1 year and 23% at 3 years in the first treatment period; 11% at the same intervals in the second treatment period; and 6% at the same intervals in the third treatment period. Our results suggest that it is important in the treatment of variant angina pectoris not only to prevent anginal attacks by the use of fast-acting coronary vasodilators, but also to initiate early revascularization.

Effect of nitroglycerin on coronary collateral function during exercise evaluated by quantitative analysis of thallium-201 single photon emission computed tomography

A noninfarcted, entirely collateral-dependent myocardial region provides an opportunity to assess the effect of nitroglycerin on coronary collateral function during exercise. Stress thallium-201 computed tomography was performed in seven patients with effort angina and no history of myocardial infarction, both before and after nitroglycerin (0.3 mg). All patients had single-vessel disease with total or subtotal (99% with delay) occlusion of proximal left anterior descending coronary artery and well-developed collaterals. The pressure-rate product, mean blood pressure, and heart rate at peak exercise did not differ before and after nitroglycerin. The size of the perfusion defect and the severity of ischemia during exercise estimated by quantitative analysis of thallium-201 single photon emission computed tomography were significantly less after nitroglycerin administration (extent score: 23 +/- 17 vs 7 +/- 9, p less than 0.01; severity score: 20 +/- 22 vs 3 +/- 4, p less than 0.05). The pressure-rate products at peak exercise did not differ before and after nitroglycerin, which suggested that the reduction in perfusion defect size was unlikely to be the result of decreased myocardial oxygen consumption. These results suggest that nitroglycerin improved coronary collateral function during exercise and thus prevented exercise-induced myocardial ischemia.

Exercise-induced silent myocardial ischemia in patients with vasospastic angina

To clarify the incidence and clinical characteristics of exercise-induced myocardial ischemia in patients with vasospastic angina, we performed exercise thallium computed tomography in 25 patients who had no significant coronary artery stenosis greater than 70%. Coronary artery spasm was documented by coronary angiography in all patients. Eleven patients (44%) developed exercise-induced perfusion defects, but only four of them had anginal pain (36%). Diltiazem (90 mg, administered orally) prevented the development of exercise-induced perfusion defects in all patients. Multivessel coronary spasm was documented by coronary angiography in 11 patients, and nine of them (82%) showed exercise-induced perfusion defects (p less than 0.05).

CONCLUSION

(1) Exercise-induced myocardial ischemia was demonstrated in 44% of patients who had vasospastic angina without fixed coronary stenosis, and 64% of them were asymptomatic. (2) Patients with multivessel spasm had a greater prevalence of exercise-induced myocardial ischemia than those with single-vessel spasm.

Suppression of exercise-induced angina by magnesium sulfate in patients with variant angina

The effects of intravenous magnesium on exercise-induced angina were examined in 15 patients with variant angina and in 13 patients with stable effort angina and were compared with those of placebo. Symptom-limited bicycle exercise and thallium-201 myocardial scintigraphy were performed after intravenous administration of 0.27 mmol/kg body weight of magnesium sulfate and after placebo on different days. In all patients, serum magnesium levels after administration of magnesium sulfate were about twofold higher than levels after placebo. Exercise-induced angina associated with transient ST segment elevation occurred in 11 patients with variant angina receiving placebo and in only 2 of these patients receiving magnesium (p less than 0.005). On the other hand, exercise-induced angina was not suppressed by magnesium in any patient with stable effort angina. In these patients there was no significant difference in exercise duration after administration of placebo versus after administration of magnesium. The size of the perfusion defect as measured by thallium-201 scintigraphy was significantly less in patients with variant angina receiving magnesium than that in those receiving placebo (p less than 0.001), whereas it was not significantly different in patients with stable effort angina receiving placebo versus magnesium. In conclusion, exercise-induced angina is suppressed by intravenous magnesium in patients with variant angina but not in patients with stable effort angina. This beneficial effect of magnesium in patients with variant angina is most likely due to improvement of regional myocardial blood flow by suppression of coronary artery spasm.

Long-term prognosis for patients with variant angina and influential factors

Two hundred forty-five patients with variant angina were followed for an average of 80.5 months (range, 36-184 months). Survival rate at 1, 3, 5, and 10 years was 98%, 97%, 97%, and 93%, respectively. Survival rate without myocardial infarction at 1, 3, 5, and 10 years was 86%, 85%, 83%, and 81%, respectively. By univarite analysis, ST segment elevation in both the anterior and inferior electrocardiographic leads was the most important factor influencing survival, followed by use of calcium antagonists, left ventricular function, smoking, and alcohol intake. The variables that significantly correlated with survival without myocardial infarction were use of calcium antagonists, left ventricular function, extent and severity of coronary artery disease, coronary artery bypass surgery, and disease activity. Multivariate analysis using the Cox proportional hazards model showed that intake of calcium antagonists, extent and severity of coronary artery disease, and ST segment elevation in both the anterior and inferior leads were significant independent predictors of survival without myocardial infarction. We conclude that long-term prognosis for patients with variant angina is relatively good and that use of calcium antagonists improves it.

Multivessel coronary spasm in patients with variant angina: a study with intracoronary injection of acetylcholine

Multivessel coronary spasm has been described but its incidence in patients with variant angina still remains unclear. Thirty-three patients with variant angina were studied during coronary angiographic examination with selective intracoronary injection of acetylcholine (ACh). In all but three patients, the location of ischemia during attack was determined by the electrocardiographic findings, by exercise 201Tl myocardial scintigraphy, and by two-dimensional echocardiography during a hyperventilation test, and the coronary artery (or arteries) responsible for the attack was predicted before the study. ACh induced spasm of at least one coronary artery in all but one patient. ACh induced spasm of both the left and right coronary arteries (i.e., multivessel coronary spasm) in 24 patients: in two of the four patients who were predicted to have spasm of the left coronary artery, in six of the 11 predicted to have spasm of the right coronary artery, in 13 of the 15 predicted to have spasm of both the left and right coronary arteries, and in three of the three in whom coronary artery responsible for attack had not been predicted. This ACh-induced spasm of the left and right coronary arteries occurred separately and no patients showed hemodynamic instability during attack. In one patient in whom multivessel coronary spasm had been predicted and ACh failed to induice coronary spasm, ergonovine maleate (0.2 mg) induced spasm of both the left and right coronary arteries simultaneously, resulting in severe prolonged hypotension. Nineteen of the 25 patients in whom multivessel coronary spasm was documented showed angiographically normal or nearly normal coronary arteries after administration of nitroglycerin.(ABSTRACT TRUNCATED AT 250 WORDS)