Spontaneous remission is a frequent outcome of variant angina

Coronary spasm and vasomotor dysfunction as a cause of MINOCA

Increasing evidence has shown that coronary spasm and vasomotor dysfunction may be the underlying cause in more than half of myocardial infarctions with non-obstructive coronary arteries (MINOCA) as well as an important cause of chronic chest pain in the outpatient setting. We review the contemporary understanding of coronary spasm and related vasomotor dysfunction of the coronary arteries, the pathophysiology and prognosis, and current and emerging approaches to diagnosis and evidence-based treatment.

Pathobiology and evolving therapies of coronary artery vasospasm

Coronary artery vasospasm is a known cause of chest pain and requires a high level of clinical suspicion for diagnosis. It also remains in the differential diagnosis for patients presenting with type 2 myocardial infarction. There are few randomized controlled trials for guideline-based prevention and treatment for coronary artery vasospasm. In this article, we review updated concepts in coronary artery vasospasm. Specifically, our aim is to provide current evidence of pathophysiology, identify the risk factors, propose a diagnostic algorithm, review available evidence of evolving therapies, and identify patients who would benefit from automatic implantable cardioverter defibrillators.

Impairment of platelet NO signalling in coronary artery spasm: role of hydrogen sulphide

BACKGROUND AND PURPOSE

The pathophysiology of coronary artery spasm (CAS), with its associated ischaemic crises, is currently poorly understood and treatment is frequently ineffective. In view of increasing evidence that platelet-based defects may occur in CAS patients, we investigated platelet reactivity in CAS patients and whether symptomatic crises reflect activation of platelet-endothelial interactions.

EXPERIMENTAL APPROACH

CAS patients were evaluated during acute and/or chronic symptomatic phases and compared with healthy control subjects. Inhibition of ADP-induced platelet aggregation by the NO donor sodium nitroprusside (SNP) and plasma concentrations of syndecan 1 (glycocalyx shedding marker), tryptase (mast cell activation marker) and platelet microparticles were measured.

KEY RESULTS

Inhibition of platelet aggregation by SNP was diminished in chronic CAS, with further (non-significant) deterioration during symptomatic crises, whereas plasma concentrations of syndecan 1, tryptase and platelet microparticles increased. Treatment of patients with high-dose N-acetylcysteine (NAC) plus glyceryl trinitrate rapidly increased platelet responsiveness to SNP and decreased plasma syndecan 1 concentrations. The effect of NAC on platelet responsiveness to SNP was confirmed in vitro and mimicked by the H₂ S donor NaHS. Conversely, inhibition of enzymatic production of H₂ S attenuated NAC effect.

CONCLUSION AND IMPLICATIONS

CAS is associated with substantial impairment of platelet NO signalling. During acute symptomatic exacerbations, platelet resistance to NO is aggravated, together with mast cell activation and damage to both vasculature and platelets. NAC, via release of H₂ S, reverses platelet resistance to NO and terminates glycocalyx shedding during symptomatic crises: This suggests that H₂ S donors may correct the pathophysiological anomalies underlying CAS.

Clinical roles of calcium channel blockers in ischemic heart diseases

Calcium (Ca) channel blockers (CCBs) inhibit Ca²⁺ channels in the myocardium or vascular smooth muscle cells, inhibit myocardium contraction, inhibit the impulse conduction system (anti-arrhythmias) and cause vasodilation. New classifications based on subtypes of Ca channels and α1 subunits have been proposed. Moreover, CCBs have pleiotropic effects on coronary spastic angina (CSA), including variant angina, myocardial infarction (MI) and stent thrombosis (ST). Although the roles of CCBs in clinical situations remain unknown, further studies in this field are expected to broaden our understanding. In this article, we explain the clinical roles of CCBs in ischemic heart diseases, such as CSA, MI and ST, based on previous knowledge and as demonstrated in representative clinical trials.

Anginalike pain and normal coronary arteries

Atherosclerotic CAD is the most common cause of cardiac chest pain in Western countries. Other cardiac syndromes may also cause anginalike pain and may be difficult to differentiate from atherosclerotic CAD. It is essential to make this distinction, because management and prognosis of these conditions are entirely different. A detailed history and, in some cases, special diagnostic methods can help make the diagnosis. When evaluating patients with anginalike chest pain and normal coronary arteries, physicians need to consider this group of diseases and tailor workup and diagnosis on an individual basis.

Role of coronary vasoconstriction in ischemic heart disease and search for novel therapeutic targets

Atherothrombosis has long been recognized as an important mechanism of cardiac events in ischemic heart disease, and large multicenter clinical studies have shown the benefit of antiplatelet agents, statins, beta-blockers and angiotensin converting enzyme inhibitors in preventing these events. However, more recent studies have been less successful at showing incremental gains in targeting these mechanisms, suggesting that the limits of this strategy have been exploited. Coronary vasoconstriction is another important mechanism in ischemic heart disease but has received little attention and yet is a potential therapeutic target. In the current review, the reasons why coronary vasconstriction has received insufficient consideration are explored. In particular, we need to change our approach from lumping heterogeneous clinical entities together to focusing on clinically-discrete homogeneous groups with a common mechanism and thus therapeutic target. The role of coronary vasoconstriction is examined in the various ischemic syndromes (variant angina, chronic stable angina, acute coronary syndromes and syndrome X) and the underlying mechanisms discussed. Finally, in order to advance studies in this field, an innovative research strategy is proposed, including: (1) selection of paradigmatic cases for the various ischemic syndromes; (2) candidate therapeutic targets; and (3) approaches in assessing the clinical efficacy of these potential therapies.

Prinzmetal's variant angina

Although the prevalence of variant angina pectoris is unknown, it appears to be substantially less common than typical, exertional angina and unstable angina at rest. The patient with variant angina typically complains of a pressure-like, squeezing retrosternal chest discomfort of several minutes duration. The diagnosis is secured by the occurrence of transient ST-segment elevation in association with chest pain, both of which resolve spontaneously or with nitroglycerin. After the diagnosis is made, the patient usually becomes symptom-free on calcium-channel blockers with or without long-acting nitrates. Although the long-term survival of these patients is excellent, an occasional individual with variant angina sustains a complication, most often myocardial infarction, a life-threatening arrhythmia, or sudden cardiac death.

A long-acting calcium antagonist over one year did not improve BMIPP myocardial scintigraphic imagings in patients with pure coronary spastic angina

BACKGROUND

Calcium antagonists (Ca) have been effective in reducing angina attacks in patients with variant angina. However, there are no reports regarding the effectiveness of Ca on myocardial fatty acid metabolic images in patients with pure coronary spastic angina (CSA).

OBJECTIVES

This study sought to examine the correlation between myocardial fatty acid metabolic images and the medical treatment of Ca in patients with pure CSA.

METHODS AND RESULTS

This study included 35 consecutive patients (28 men, mean age of 66 +/- 10 years) with angiographically confirmed coronary spasm and no fixed stenosis. Long-acting Ca was administered to all 35 patients. Isosorbide dinitrate /nicorandil/another Ca/beta-bloker were administered when chest pain was not controlled. Using an iodinated fatty acid analogue, 15-(p-[iodine-123]iodophenyl)-3-(R,S)methylpentadecanoic acid (BMIPP), myocardial scintigraphies with intravenous adenosine triphosphate infusion were performed before cardiac catheterization and 12 mo after medical therapy. According to the medical control states, these 35 patients were classified into 3 groups; response (disappearance of angina attacks, 12 pts, 60 +/- 11 years), partial response (angina attacks < 4/mo, 12 pts, 67 +/- 10 years), and no response to therapy (angina attacks > or = 4/mo, 11 pts, 71 +/- 6 years). Reduced BMIPP uptake was observed in 24 (69%) of 35 patients before the treatment. Reduced BMIPP uptake was also found in 18 patients (51%) after 12 mo. Normal BMIPP uptake after 12 mo therapy was observed in about half (response: 42%, partial response: 58%, no response: 45%) of patients among the 3 groups. There was no difference regarding the value of washout rate (WOR) (response; 10 +/- 7 (before), 14 +/- 8% (12 mo)), partial response; 11 +/- 7, 10 +/- 5%, no response; 13 +/- 9, 14 +/- 8%) among the 3 groups. The defect scores of BMIPP in the three groups were not different during at least one year medical therapy. No difference regarding the distribution of other medical therapies (angiotensin converting enzyme inhibitors/angiotensin receptor blockers/beta-blockers/statins) was found. The administration of Ca and isosorbide dinitrate/nicorandil and 2 Ca was significantly higher in the poor than in the good control patients.

CONCLUSIONS

Long-acting Ca over one year did not improve myocardial fatty acid metabolic images in patients with pure CSA. This may be related to silent ischemia.

Did the Widespread Use of Long-Acting Calcium Antagonists Decrease the Occurrence of Variant Angina?

BACKGROUND

We have not often encountered variant angina (VA) since the use of long-acting calcium antagonists (L-CAs) became widespread.

OBJECTIVES

This study examined the frequency of VA retrospectively.

METHODS

and results: We diagnosed angiographically confirmed coronary spastic angina (CSA) in 349 consecutive patients using selective spasm provocation tests from January 1991 to December 2002. During this period, 3,148 diagnostic cardiac catheterizations and 1,515 selective spasm provocation tests were performed. Seventy-four of these 349 patients (21.2%) had VA. Coronary spasms were defined as transient luminal narrowings of > 99%, and VA was defined as an ST elevation during spontaneous attacks or noninvasive stress tests. We classified the 12 years of the study into four periods of 3 years each. No tendency to decrease for the ratio of the number of patients with CSA and the number of selective spasm provocation tests was observed among the four time periods (18%, 24%, 32%, and 23%, respectively). However, the number of patients with VA (28, 33, 9, and 4) and the VA/CSA ratio (32%, 28%, 14%, and 5%, respectively) in the four group significantly decreased. The frequency of administration of calcium antagonists (CAs) before hospital admission (49% vs 33%, respectively; p < 0.05) was significantly higher in the last time period (from 2000 to 2002) than in the first period (from 1991 to 1993). L-CAs were administered in > 90% of CSA patients who had been medicated with CAs before hospital admission in the last period (from 2000 to 2002), while L-CAs were administered in only 20% in the former period (from 1991 to 1993). The administration of statins and angiotensin-converting enzyme inhibitors/angiotensin receptor blockers before hospital admission gradually increased according to the period passed, but not significantly.

CONCLUSION

The frequency of VA has decreased in Japan, possibly due to the widespread use of therapy with L-CAs.

Coronary flow reserve in patients with vasospastic angina: correlation between coronary flow reserve and age or duration of angina

OBJECTIVES

This study sought to assess the coronary flow reserve (CFR) in patients with pure vasospastic angina (VSA).

METHODS AND RESULTS

The phasic flow velocities of both spasm-positive and spasm-negative coronary arteries of the left anterior descending artery (LAD) were recorded at rest and during hyperaemia (50 microg of adenosine triphosphate infusion intracoronary) using a 0.014 inch, 15 MHz Doppler guide wire in 42 patients with pure VSA and acetylcholine (ACh)-induced coronary artery spasms (20-100 microg), and 23 controls with normal coronary arteries without ACh-induced vasospasm. These 42 patients had 16 vessels with focal spasms (>99%), 17 vessels with diffuse spasms (>90%) in the LAD, and nine vessels with ACh-induced spasms in the right coronary artery, but not the LAD. Coronary flow reserve was obtained from the ratio of the hyperaemic/baseline time-averaged peak velocity. Coronary flow reserve did not differ between patients with VSA and the controls (2.9+/-0.8 versus 3.2+/-0.7, NS). Moreover, CFR did not differ among the four cases (focal: 2.8+/-0.7; diffuse: 3.0+/-0.9; non spasm: 2.9+/-0.7 versus controls: 3.2+/-0.7, respectively, NS). Coronary flow reserve in vessels with proximal spasms was significantly higher than that in vessels with mid or distal spasms (3.4+/-0.8 versus 2.6+/-0.6, 2.6+/-0.9, p<0.05). The only significant correlation was between CFR and age (p=0.0275) or the duration of angina before admission (p=0.0405).

CONCLUSIONS

There was no difference in CFR in patients with ACh-induced spasms between the spasm-positive and spasm-negative vessels. Moreover, CFR was maintained normally in vessels with diffuse spasms, as in those with focal spasms. The most important determinant factors for CFR in patients with VSA were age and the duration of angina before admission.

Limitations of medical therapy in patients with pure coronary spastic angina

OBJECTIVES

To assess the efficacy of medication for the treatment of pure coronary spastic angina, 71 consecutive patients with this diagnosis who had undergone coronary arteriography in a hospital with a follow-up of at least 2 years were studied.

METHODS AND RESULTS

All 71 patients without significant organic stenosis were treated with long-acting calcium antagonists. The disappearance of chest pain attacks while receiving medical therapy was observed in 27 patients (38%), whereas the remaining 44 patients (62%) had chest pain attacks. Of special interest, 30 patients had more than one attack per month irrespective of the administration of calcium antagonists or isosorbide dinitrate. Medical treatment showed a good response in female patients (63% vs 31%, respectively; p < 0.05) and those with ST-segment elevation during selective spasm provocation tests (63% vs 30%, respectively; p < 0.05). In contrast, patients with a longer history of chest pain attacks before hospital admission and those with diffuse spasms (77% vs 34%, respectively; p < 0.01) had poor responses to medical treatment. In this study, neither sudden death nor acute myocardial infarction was observed during the follow-up periods.

CONCLUSION

The limitations of medical therapy, including the administration of long-acting calcium antagonists, were observed in 30 of 71 patients (42%) with pure coronary spastic angina. Medical treatment was effective in only 38% of patients with pure coronary spastic angina in Japan.

Long lasting spasticity in controlled vasospastic angina

OBJECTIVE

To evaluate changes in coronary artery spasticity in patients with vasospastic angina who had been stable for years under continuous drug treatment.

METHODS

Follow up coronary angiography was performed under intracoronary ergonovine provocation in 27 well controlled patients with vasospastic angina and no organic stenosis; the tests were done > 24 months after the initial coronary angiography, in which occlusive spasm had been induced by the same regimen of ergonovine provocation.

RESULTS

The mean (SD) follow up period was 47.2 (21.6) months. All patients had been free from angina attack for more than 24 months under treatment with antianginal drugs. During this follow up period, organic stenosis developed in only one case. Occlusive spasm was observed during follow up coronary angiography in 23 patients. Spasm with 90% narrowing was observed in three other patients, and diffuse significant narrowing was seen in the final patient. No significant difference was found in spasticity (p = 0.75) between the initial and the follow up tests.

CONCLUSIONS

Repeated ergonovine provocation during coronary angiography after a controlled period of several years showed that coronary spasm remains inducible in most patients. Discontinuance of drug treatment during the remission from anginal attacks achieved by medication may put the patient at high risk.

Evolution of coronary vascular tone in vasospastic angina

In general, anginal symptoms diminish with time in patients with vasospastic angina. We assessed changes in coronary vascular tone (CVT) in patients with vasospastic angina over a 4-year period to evaluate the time course of spastic activity. Vasospastic angina was evaluated in 39 patients in whom occlusive spasm was evoked by selective intracoronary injection of ergonovine maleate (ERG-S) 48 h after stopping all coronary vasodilator drugs. These patients had no organic coronary stenosis and developed no stenosis during follow-up. ERG-S was repeated 3 times at 2-year intervals. CVT was determined at each ERG-S study using the equation: CVT = 1-(coronary artery diameter before ERG-S/coronary artery diameter after intracoronary injection of isosorbide dinitrate). Thirty-four patients (87%) had no angina pectoris at the second ERG-S study and 28 (72%) had none at the third. Coronary spasm was induced in 25 patients at the second ERG-S study and in 20 at the third. The overall CVT was shown to decrease at each successive ERG-S study (p < 0.01). There was no correlation between changes in CVT and anginal symptoms or the coronary spasm induction rate. These results demonstrate that CVT decreases over time in patients with vasospastic angina, suggesting that myocardial ischemia may improve spontaneously.

Sympathetic nerve activity in the spasm-induced coronary artery region is associated with disease activity of vasospastic angina

OBJECTIVES

We assessed the relation between sympathetic nerve activity and disease activity of vasospastic angina.

BACKGROUND

The autonomic nervous system has been proposed to play a key role in attacks of vasospastic angina. A unique feature of vasospastic angina attacks is periodic fluctuation, which complicates the assessment of disease activity.

METHODS

Twenty-five patients with left anterior descending coronary artery (LAD) spasm were studied: 12 with recent onset of chest pain (group 1) and 13 free of angina for more than 3 months after discontinuing medication (group 2). Group 1 underwent iodine-123 metaiodobenzylguanidine (MIBG) imaging (in the active phase) and atropine-stress MIBG imaging early after diagnostic angiography, and repeat MIBG imaging when they were free of angina for more than 3 months with medication (in the stable phase). Group 2 also underwent MIBG imaging (in remission). On a bull's-eye map, quantitative analysis of percent uptake and washout rate of MIBG was performed regionally.

RESULTS

In group 1 in the active phase, the washout rate of the LAD territory was significantly lower than the rates in the stable phase, in remission and during atropine-stress MIBG imaging. The regional washout rate of the territories of the right coronary artery and the circumflex artery in the active phase was also significantly lower than that during atropine-stress MIBG imaging. The washout rate of the LAD territory in the active phase was significantly lower than the rates of the other two regions. In contrast, there were no significant differences in the distribution of regional percent uptake in every image. A similar distribution of washout rate was observed among group 1 patients in the stable phase, in group 1 patients during atropine-stress MIBG imaging and in group 2 patients.

CONCLUSIONS

The MIBG washout rate of the spasm-induced coronary artery territory changed according to the degree of disease activity. Thus, sympathetic nerve activity could reflect disease activity of vasospastic angina.

Chronic treatment with interleukin-1 beta induces coronary intimal lesions and vasospastic responses in pigs in vivo. The role of platelet-derived growth factor

Studies in vitro have suggested that inflammatory cytokines may play an important role in the pathogenesis of atherosclerosis. However, little is known about their effects in vivo. Thus, the present study was designed to determine in vivo what histological and functional changes may be induced by chronic treatment with IL-1 beta, one of the major inflammatory cytokines, and also to clarify what mechanisms are involved in those changes. Under aseptic conditions, proximal segments of the left porcine coronary arteries were gently wrapped with cotton mesh absorbing Sepharose beads either with or without recombinant human IL-1 beta. From 1 to 4 wk after the operation, coronary vasospastic responses to intracoronary serotonin or histamine were noted at the IL-1 beta-treated site but not at the control site. Histologically, intimal thickening was greater at the IL-1 beta-treated site than at the control site. Those functional and histological changes induced by the chronic treatment with IL-1 beta were significantly inhibited by the simultaneous treatment with a neutralizing antibody to either IL-1 beta or PDGF. These results indicate that chronic treatment with Il-1 beta induces coronary intimal lesions and vasospastic responses in porcine coronary arteries in vivo and also suggest that these changes are substantially mediated by PDGF.

Fluctuation of spastic location in patients with vasospastic angina: a quantitative angiographic study

OBJECTIVES

This study sought to determine whether the location of coronary spastic activity may change over time in patients with persistent variant angina.

BACKGROUND

Although electrocardiographic studies have provided indirect evidence to indicate that the location of ischemia may change in patients with variant angina, it has not been tested by quantitative angiography whether the location of vasospastic activity may change over time.

METHODS

Paired ergonovine provocation tests and coronary angiography were performed at a mean (+/- SD) interval of 43 +/- 13 months apart in patients with persistent symptoms of vasospastic angina in the absence of significant atherosclerosis. A total of 87 spastic and nonspastic segments of 87 major vessels in 29 patients were analyzed by quantitative angiography at baseline, after the administration of ergonovine and after isosorbide dinitrate at the initial and follow-up tests.

RESULTS

In 13 patients (group 1), coronary spasm was observed in the same 16 coronary segments at both the initial and follow-up ergonovine provocation tests. In 16 patients (group 2), the following angiographic changes occurred between the initial and follow-up tests in 48 major vessels: Of the 23 segments that developed spasm at the initial test, 10 did not have spasm at the follow-up test; of the 25 vessels that did not demonstrate spasm on the initial test, 12 demonstrated spasm on the follow-up test (a new site of spasm). Thus, in 22 (46%) of 48 vessels, fluctuation of spastic location was observed at follow-up.

CONCLUSIONS

Quantitative coronary angiography and repeated ergonovine tests revealed that some patients with persistent vasospastic angina demonstrate fluctuation of vasospastic location, whereas others exhibit a fixed location of vasospasm. Vasospastic angina may not only be a transient disease restricted in location, but may also be a persistent and variable condition involving multiple vessels over many years.

Randomized placebo-controlled trial of amlodipine in vasospastic angina. Amlodipine Study 160 Group

OBJECTIVES

This study was designed to assess the efficacy and safety of amlodipine, a long-acting calcium channel blocker, in patients with vasospastic angina.

BACKGROUND

Previous studies have established the value of short-acting calcium channel blockers in the treatment of coronary spasm.

METHODS

Fifty-two patients with well documented vasospastic angina were entered into the present study. After a single-blind placebo run-in period, patients were randomized (in a double-blind protocol) to receive either amlodipine (10 mg) or placebo every morning for 4 weeks. Twenty-four patients received amlodipine and 28 received placebo. All patients were given diaries in which to record both the frequency, severity, duration and circumstances of anginal episodes and their intake of sublingual nitroglycerin tablets.

RESULTS

The rate of anginal episodes decreased significantly (p = 0.009) with amlodipine treatment compared with placebo and the intake of nitroglycerin tablets showed a similar trend. Peripheral edema was the only adverse event seen more frequently in amlodipine-treated patients. No patient was withdrawn from the double-blind phase of the study because of an adverse event. Patients who completed the double-blind phase as responders to amlodipine or as nonresponders to placebo were offered the option of receiving amlodipine in a long-term, open label extension phase. During the extension, the daily dose of amlodipine was adjusted to 5 or 15 mg if needed and the rate of both anginal episodes and nitroglycerin tablet consumption showed statistically significant decreases between baseline and final assessment.

CONCLUSION

This study suggests that amlodipine given once daily is efficacious and safe in the treatment of vasospastic angina.

Long-term study of recurrent vasospastic angina using coronary angiograms during ergonovine provocation tests

Chronologic changes of coronary spasm were examined by repeated ergonovine provocation tests during angiography. A total of 322 patients who had variant angina without severe atherosclerosis demonstrated a positive response to the first test. Ninety of these patients had recurrent variant anginal symptoms after an angina-free period of 38 +/- 12 months (mean +/- SD). Of these 90 patients, 76 (84%) had symptoms or electrocardiographic (ECG) findings similar to those of the first test. The initial 9 of these 76 patients underwent a second provocation test and showed coronary responses analogous to those on the first test. Of the 90 patients, 14 (16%) had different symptoms or ECG findings from those elicited at the first episode. All 14 patients again had a positive response to a second ergonovine test and the following angiographic changes were observed in the three major vessels between the two tests. Of the 21 vessels that had spasm on the first test, eight vessels (19%) did not have spasm on the second test. Of the 21 vessels that did not demonstrate spasm on the first test, 10 (24%) demonstrated spasm on the second test. In the present study it is concluded that the majority of patients with recurrent angina seemed to have consistency in the location of coronary spasm, while in some patients the fluctuation of coronary spasm was confirmed by two ergonovine provocation tests.

Felodipine (once daily) versus nifedipine (four times daily) for Prinzmetal's angina pectoris

In 30 consecutive patients with Prinzmetal's angina pectoris, the antiischemic effect of felodipine, a new long-acting vasoselective calcium antagonist, administered at doses of 10 and 20 mg once daily was compared with that of the well-established therapeutic regimen with nifedipine administered at a dose of 20 mg 4 times daily. Twenty-four-hour Holter monitoring was performed during a 2-day placebo run-in and at the end of each of 3 consecutive 6-day periods during which the 3 active treatments were administered in randomized sequence. Three patients withdrew, whereas 27 completed the study. The therapeutic regimens tested proved to be similarly effective; primary end points (ischemic episodes recorded by Holter monitoring, and anginal attacks reported on diary cards) occurred in 5 patients (19%) during nifedipine treatment, and in 7 (26%) and 3 (11%) during felodipine treatment with 10 and 20 mg, respectively (p = not significant). The distribution of residual ischemic episodes demonstrated that treatment with felodipine once daily provides 24-hour antiischemic protection. Twenty-six patients were followed up with 20 mg of felodipine once daily for a mean of 6 +/- 5 months, and 21 of them (81%) remained free of symptoms and Holter-recorded ischemic attacks. It is concluded that for Prinzmetal's angina pectoris, 24-hour antiischemic protection may be achieved with administration of felodipine once daily. The availability of a simplified therapeutic approach may constitute a real advantage in terms of patient compliance and improving the quality of life.

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.

Comparative effects of oral molsidomine and nifedipine on methylergometrine-induced coronary artery spasm

Twelve consecutive patients (10 men and 2 women, mean +/- standard deviation age 49 +/- 9 years) with chest pain, angiographically normal coronary arteries and coronary artery spasm documented by methylergometrine testing received a single oral dose of molsidomine (4 mg) or nifedipine (10 mg) in a randomized, double-blind, crossover fashion at a 24-hour interval. Coronary artery spasm was documented during coronary angiography in 6 patients (left anterior descending artery, 3; right coronary artery, 2; left circumflex, 1). In the remaining 6 patients, coronary artery spasm was documented by a positive methylergometrine test performed at the bedside, which provoked ST-segment elevation in the inferior (n = 3), anterior (n = 1) or lateral (n = 2) leads. Ninety minutes after administration of the study medication, methylergometrine testing was performed at the bedside, using incremental doses of up to 0.4 mg of methylergometrine. After molsidomine, 10 patients (83%) had a negative and 2 had a positive test; after nifedipine, 9 patients (75%) had a negative and 3 a positive test. Only 1 patient had a methylergometrine test that remained positive after either molsidomine or nifedipine. Therefore, molsidomine appears as effective as nifedipine in suppressing methylergometrine-induced coronary artery spasm in patients with variant angina. In addition, patients not responding to 1 of the study medications may respond to the other.

Endothelium-derived relaxing factor and coronary vasospasm

The endothelium releases the powerful vasodilator and antiaggregatory substance, EDRF, both under basal conditions and upon stimulation by a wide variety of agents. Endothelial injury or dysfunction may play an important role in the spasmogenicity of the coronary artery, although other possible alterations related to atherosclerosis should also be considered. Among the possible stimuli, aggregating platelets are important as a source of vasoconstrictor substances. The endothelium may also produce the vasoactive substances EDHF and EDCF(s). Their pathophysiologic significance remains to be determined.

Different coronary vasomotor effects of nifedipine and therapeutic correlates in angina with spontaneous and effort components versus Prinzmetal angina

Flow impedance, probably of vasomotor origin, superimposed on severe coronary stenosis has been considered a trigger for the spontaneous component of angina occurring both on effort and at rest. To investigate more thoroughly this pathophysiologic aspect we evaluated (by means of quantitative coronary angiography) the acute vasomotor reaction to nifedipine (10 mg sublingually) of significant (greater than 50%) stenotic lesions in 22 patients with double-component angina. We also correlated this reaction with the clinical response (daily number of ischemic episodes evaluated by means of 48-hour Holter ambulatory monitoring) to treatment with nifedipine (20 mg four times a day); calcium channel blockade, in fact, is considered a specific remedy in cases of altered coronary vasomotility. Patients with Prinzmetal angina, who were known to have homogeneous coronary vasodilating reactions and favorable clinical responses to nifedipine, were studied by means of the same methods and served as the control group (14 patients). In double-component angina the residual lumen diameter of significant lesions was unchanged in two patients, enhanced in 10, and reduced in 10 after sublingual nifedipine; lumen variations from baseline values ranged from +1.29 to -1.56 mm. Acute changes in stenosis correlated closely with results obtained with oral treatment. In the group with Prinzmetal angina, coronary stenoses invariably responded with dilatation (the residual coronary lumen increased by an average of 69% of baseline); 100% of the patients in this group responded favorably to treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Different vasomotor action of nifedipine on dynamic coronary obstructions and therapeutic response in effort and prinzmetal angina

Variations induced by nifedipine (10 mg sublingually) in the residual lumen diameter of significant (greater than 50%) coronary lesions were assessed angiographically in 58 patients with effort angina (group 1) and in 19 patients with Prinzmetal angina (group 2). A relationship was sought between these acute variations of the stenotic lumen and the clinical response to treatment with the same drug (20 mg four times daily). Treatment efficacy was evaluated with exercise testing in group 1 and Holter monitoring in group 2. In group 1 the residual segment of stenotic diameter showed an increase, decrease, or no change with the calcium antagonist. Nifedipine failed to improve 40% of the cases (21% unchanged and 19% worsened) in group 1. In the same group of patients, the responses to exercise tests were dissociated from the acute vasomotor pattern. Changes in the pressure-rate product also did not explain the clinical results. In group 2 the majority of lesions had compliant portions, which invariably reacted to nifedipine with dilatation. All patients with the Prinzmetal form had relief of the anginal episodes with treatment. These data suggest that the therapeutic efficacy of nifedipine in classic effort angina probably is the net result of influences on the myocardial oxygen consumption and supply, and the acute coronary vasomotor pattern does not allow to predict the clinical response. Stenotic lesions in the Prinzmetal form possess a distinct sensitivity to the relaxant action of calcium channel blockade, which reasonably explains the highly positive response to treatment.

Early evolution of symptoms and long-term prognosis in variant angina: importance of the functional component of coronary arterial disease

PURPOSE

Most investigations describing the long-term outcome of large groups of patients with variant angina pectoris have focused on such endpoints as myocardial infarction, coronary artery surgery, and death, and have asked how the risk of these events is related to the severity of existing organic coronary disease. It is also possible to ask what is the relative importance of organic and functional components in causation of symptoms and outcomes, as was done in this study.

PATIENTS AND METHODS

The early and long-term clinical course was observed in a group of 80 patients with variant angina and a low prevalence of severe organic coronary disease (diameter stenosis greater than 70 percent of one vessel in 28.3 percent, of two or more vessels in 2.7 percent). Patients were seen at the UCLA Medical Center between July 1963 and June 1985.

RESULTS

The following observations were made: Compared with those experiencing a first episode of angina at rest, subjects whose first episode of vasospastic angina occurred during strenuous effort were more likely subsequently to have a positive exercise test result and a more stable but long-term anginal course. A good initial response to vasodilator therapy indicated a likelihood of being alive and symptom-free without an intervening myocardial infarction by five years after diagnosis, which was twice the rate as if initial response to such treatment was poor. The presence or absence of severe coronary artery obstruction as detected by angiography could not be predicted from the nature or severity of angina, the historical presence of effort angina, or the occurrence of a positive result on an exercise test. The existence of severe coronary stenosis in at least one vessel was not associated with an increased incidence of myocardial infarction, cardiac arrest, or death in the first nine years after diagnosis.

CONCLUSION

These findings are consistent with the hypothesis that manifestations of ischemic heart disease in these patients were more directly caused by coronary vasospasm than by the degree of organic coronary obstruction seen by coronary arteriography. In addition, the presence of severe organic stenosis in one coronary artery did not appear to be associated with measurably increased adverse effects on clinical course or survival over the first nine years after diagnosis.

Coronary vasomotor and clinical effects of nifedipine in effort, mixed and Prinzmental angina

Changes induced by nifedipine (10 mg s.l.) in the residual lumen diameter of significant (greater than 50%) coronary lesions were assessed angiographically in 69 patients with effort angina (Group 1), in 22 patients with mixed angina (Group 2), and in 14 patients with Prinzmental angina (Group 3). These changes were related to the clinical response to treatment with the same drug (diary records, exercise testing, Holter monitoring). In Groups 1 and 2 segments of stenotic vessels showed either increase, decrease or no change in diameter with the calcium antagonist; in Group 3 the majority of the vessels showed compliant portions which invariably responded with dilatation. Nifedipine failed to improve cases with exertional (21% unchanged, 19% worsened) and mixed (41% exacerbated) forms; all patients with the Prinzmental form had relief of the anginal episodes. In Group 1, the response to exercise tests were dissociated from the acute vasomotor pattern and the pressure-rate product failed to explain the clinical results. Fifty-two percent of the patients in Group 2 showed significant acute widening of critical stenoses as well as obvious improvement; patients in this group who did worse with treatment had reacted to nifedipine with narrowing of their critical stenoses. These data suggest that: the response to nifedipine of classic effort angina is probably the net result of an interaction of changes in myocardial oxygen consumption and supply; coronary vasomotion has a role in mixed angina and influences of nifedipine may be either favorable or unfavorable; stenotic lesions in the Prinzmental form are quite sensitive to the relaxant action of calcium blockade and this probably represents a background to the highly positive clinical response to treatment.

Long-term prognosis of medically treated patients with vasospastic angina and no fixed significant coronary atherosclerosis

The clinical course of 48 consecutive patients with vasospastic angina and minor coronary atherosclerosis (no stenoses greater than 50%) was analyzed during an average follow-up period of 47 months. The study group consisted of 37 men and 11 women. Patients were treated with usual doses of calcium antagonists. One patient died (2%) and three had myocardial infarctions (6%). Seventy-one percent were asymptomatic or had infrequent angina; 13% had recurrences but had periods of remission lasting at least 10 months. Only 16% had persistent angina. None of the clinical or angiographic findings at the time of diagnosis were predictive of myocardial infarction or death, and they could not separate angina-free patients from those with recurrences. Thus, vasospastic angina without fixed coronary narrowing has a good prognosis despite the possibility of recurrences. However, there is a slight risk of myocardial infarction and death. This fact should be considered if there are plans to discontinue treatment.

Clinical characteristics and long-term prognosis of patients with variant angina. A comparative study between western and Japanese populations

To determine the factors influencing the prognosis of variant angina, the clinical characteristics and long-term prognosis of 158 consecutive Japanese patients were examined and compared with those in previous major western studies (Pisa, Montreal, and Duke studies). The Japanese patients were characterized by relatively low prevalences of coronary risk factors, significant coronary stenoses and previous myocardial infarction. Survival and survival without myocardial infarction for the entire group or for the subpopulation with significant coronary artery disease were significantly better in the Japanese population than in the western populations; however, in the subpopulation without significant coronary artery disease, the prognosis was excellent in all four studies. If the prevalence of coronary artery disease was corrected for the Japanese population, there would be no difference in the prognosis between the Japanese and the western populations. It is concluded: (1) the overall prognosis of variant angina may be better in Japanese patients, and (2) coronary artery disease appears to be the strongest prognostic factor for assessing the differences in the prognosis between the Japanese and the western populations.

Nifedipine and angina pectoris. Short-term changes in quantitative coronary angiography with nifedipine and clinical response to treatment in effort-induced, mixed, and spontaneous angina pectoris

Changes induced by nifedipine (10 mg sublingually) in the residual luminal diameter of significant (greater than 50 percent) coronary lesions were assessed angiographically in 69 patients with effort-induced angina (group 1), in 22 patients with mixed angina (group 2), and in 14 patients with Prinzmetal's angina (group 3). These changes were related to the clinical response to treatment with the same drug, as evaluated through diary records and Holter monitoring in the mixed (spontaneous component) and Prinzmetal forms and through exercise testing in effort-induced and mixed (effort-associated component) angina. In groups 1 and 2, segments of stenotic vessels showed either an increase or decrease or no change in diameter with the calcium antagonist; in group 3, the majority of the lesions had compliant portions which invariably responded with dilatation. Nifedipine failed to improve cases with exertional (20 percent [14/69] unchanged; 19 percent [13/69] worsened) and mixed (41 percent [9/22] exacerbated) forms; 100 percent of the 14 patients with the Prinzmetal form had relief of the anginal episodes. In group 1, the response to exercise tests was dissociated from the short-term vasomotor pattern, and the pressure-rate product failed to explain the clinical results. Forty-five percent (ten) of the patients in group 2 showed significant short-term widening of critical stenoses, as well as obvious improvement; patients who did worse with treatment in this group had reacted to nifedipine with narrowing of critical stenoses. These data suggest that the response to nifedipine of classic effort-induced angina is probably the net result of an interaction of changes in myocardial oxygen consumption and supply; coronary vasomotion has a role in mixed angina, and influences of nifedipine may be either favorable or unfavorable; stenotic lesions in the Prinzmetal form are quite sensitive to the relaxant action of calcium blockade, and this probably represents a background to the highly positive clinical response to treatment.

A case of variant angina exacerbated by administration of rifampicin

Rifampicin, an antituberculosis agent, is known to be a potent inducer of microsomal drug-metabolizing enzymes in the liver. Elimination or clearance of many drugs has been reported to be enhanced, and their effectiveness reduced; however, no report in the literature has dealt with the interaction between rifampicin and dihydropiridine calcium entry-blocking drugs such as nifedipine. We present here evidence for the possible interaction between rifampicin and nifedipine in a patient with angina pectoris, which was exacerbated during coadministration or rechallenge with rifampicin. The peak plasma level and area under the curve were reduced and the apparent oral clearance of nifedipine was increased by rifampicin, suggesting that rifampicin enhanced the elimination of nifedipine via induction of a hepatic microsomal drug-metabolizing enzyme, as has been reported on other drugs widely metabolized in the liver.

Restoration of endothelium-dependent relaxation by dietary treatment of atherosclerosis

Atherosclerosis results in impaired relaxation to acetylcholine, thrombin, and the calcium ionophore A23187, all agents that require the presence of endothelium. We now report that dietary treatment of atherosclerosis in monkeys not only produces morphological improvement of the atherosclerotic lesion but restores endothelium-dependent vascular relaxation to normal. Because the intima remains thickened after regression of atherosclerosis, these studies suggest that intimal thickening which is present in both atherosclerotic vessels and after regression of atherosclerosis does not prevent the endothelium-derived relaxing factor from reaching the underlying vascular smooth muscle.

Clinical characteristics associated with myocardial infarction, arrhythmias, and sudden death in patients with vasospastic angina

A total of 349 patients with vasospastic angina were followed in eight centers in Japan for a period of 3.4 +/- 0.1 years (mean +/- SE). Ninety-eight percent of patients were treated with calcium blockers. Twenty-one episodes of myocardial infarction occurred in 18 patients (5%), including two fatal myocardial infarctions. The rate of myocardial infarction was higher (p less than .01) in patients with a fixed stenosis of 90% or greater than in patients with a fixed stenosis of less than 90% or normal coronary arteries. Myocardial infarctions occurred predominantly during hospital stays or at a time when the frequency of vasospastic angina increased. There were five sudden deaths (2%). Only one patient suffering sudden death had a fixed stenosis of 75% or greater. Serious arrhythmias were noted in 49 patients (14%). The risk of arrhythmias did not depend on the presence of a fixed stenosis of 75% or greater. These results suggest that cardiac events are rather infrequent in Japanese patients with vasospastic angina who are receiving treatment with calcium blockers and that the presence of a severe fixed stenosis markedly increases the risk of myocardial infarction but not the risk of arrhythmias.

Usefulness of ST deviation induced by prolonged hyperventilation as a predictor of cardiac death in angina pectoris

One hundred ninety patients with chronic angina for an average of 2 years were followed. Forty-seven had at least 1 mm of ST deviation in response to provocation of coronary vasoconstriction by prolonged hyperventilation (group I); 143 had no ST deviation (group II). The angiographic response to this test was studied in 21 patients from group I, and revealed 25 to 100% diameter reduction; in group II 9 patients showed a 5 to 14% diameter reduction. In group I, 15 patients (32%) died (hazard rate = 0.17 deaths/patients X years) vs 18 (13%) in group II (hazard rate = 0.06) (p less than 0.01). Seven patients in group I (15%) and 3 in group 2 (2%) died while waiting for surgery (p less than 0.01). All patients who died had coronary stenoses of at least 70%. A Cox regression analysis, using 24 variables (invasive and noninvasive), showed a positive hyperventilation test (ST deviation at least 1 mm), low ejection fraction and systolic blood pressure of at least 160 mm Hg to be independent predictors of death (p less than 0.05). Considering only deaths in non-operated patients (patients waiting for surgery and patients not planned to undergo operation), a rate-pressure product/100 of 150 or less at exercise stress testing, left ventricular end-diastolic pressure of 15 mm Hg or more and duration of angina less than 1 year were also independent predictors of death. Thus, the hyperventilation test may be useful for identifying angina patients who are at high risk of cardiac death due to dynamic coronary obstructions.

Spontaneous remission of variant angina documented by Holter monitoring and ergonovine testing in patients treated with calcium antagonists

Twenty-four patients with Prinzmetal's variant angina showing a favorable initial response to calcium antagonist treatment were studied to assess the evolution of the disease and the frequency and time course of spontaneous remission. At 3, 6 and 12 months from the acute phase, patients underwent in-hospital control studies, with 48-hour Holter monitoring and ergonovine testing carried out during treatment and after its interruption. During calcium antagonist therapy complete protection from spontaneous attacks was documented in 22 of 24 patients at 3 months, in 19 of 21 at 6 months and in all 21 at 12 months; ergonovine test results were negative in 16 of 23 patients at 3 months, in 16 of 20 at 6 months and in all 20 studied at 12 months. After stopping treatment spontaneous attacks did not reappear in 7 of 24 patients (29%), 14 of 21 (66%) and 16 of 21 (76%) at 3, 6 and 12 months respectively, while the ergonovine test response remained negative in 6 of 21 (28%), 7 of 18 (39%) and 13 of 20 (65%) of the patients controlled at 3, 6 and 12 months. Thus, complete remission of angina documented by both Holter recording and ergonovine testing occurred in 5 of 24 patients (21%) at 3 months, in 7 of 21 (33%) at 6 months and in 12 of 21 (57%) at 12 months. Patients with remission of angina had a shorter duration of symptoms and more often showed normal or not critically diseased coronary arteries.(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of a variant angina on the results of percutaneous transluminal coronary angioplasty

Nineteen (86%) of 22 patients with variant angina and important coronary stenoses (greater than 60%) had successful percutaneous transluminal coronary angioplasty. The acute complications in two patients were not caused by coronary spasms but by dissection with disturbance of perfusion. One of these two patients required a coronary bypass graft; the other was treated conservatively. Myocardial infarction developed in both patients. Despite long term administration of nifedipine (30-80 mg daily), restenoses occurred within six months (on average after 10 weeks) in nine patients with symptoms and one without. In four patients the restenoses exceeded the degree of stenosis before angioplasty. Five patients were revascularised by surgical means. Vessels in three out of four patients were later successfully dilated. After a mean period of observation of 24 months (6-51 months) 18 of the 19 patients are symptom free and do not require medication. The results confirm that angioplasty is an effective method of treating patients with variant angina and important coronary stenoses. The problem of the high frequency of restenosis, however, remains unresolved.

The long-term outcome of patients who suffered and survived an acute myocardial infarction in the midst of recurrent attacks of variant angina

Twenty-one patients, ranging in age between 28 and 59 years, who survived hospitalization for an acute myocardial infarction in association with repetitive attacks of variant angina, were followed prospectively for 59.1 +/- 5.1 (SEM) (range 17-120) months. Four patients died, one of sudden death 17 months after admission, one of congestive heart failure at 33 months, and two of cancer at 43 and 45 months of follow-up. Three patients had four new myocardial infarctions at 22, 32, 33, and 61 months of follow-up. Six patients were readmitted for angina or other cardiac reasons. Twelve patients remained asymptomatic throughout the follow-up and one more patient was asymptomatic before and after his recurrent myocardial infarction. No relapse of variant angina was documented. Thus, the long-term course of patients with variant angina culminating in acute myocardial infarction is relatively benign, despite the highly unstable features of their initial presentation.

Late follow-up (41 to 102 months) of medically treated patients with coronary artery spasm and minor atherosclerotic coronary obstructions

From a series of 37 patients with coronary artery spasm and less than 70% diameter narrowing treated initially with verapamil and nitrates, 33 were followed up 41 to 102 months (mean 62). One patient died from carcinoma of the lung and 3 could not be traced. Before diagnosis, 3 had nontransmural myocardial infarction and 10 had either ventricular tachycardia and fibrillation or atrioventricular block. During follow-up there were no cardiac deaths or myocardial infarctions. Asymptomatic periods of more than 3 months occurred in 23 patients during follow-up: 18 with asymptomatic periods of more than 1 year were pain free at the time of study and 5 with asymptomatic periods of 3 to 6 months had infrequent pain. Ten patients had no asymptomatic periods. Symptomatic status at last review was related to initial response to therapy: 13 of 18 patients (72%) currently asymptomatic became asymptomatic with initial therapy compared with 5 of 15 patients (33%) currently experiencing pain (p = 0.06). Twenty-six patients were currently receiving therapy: 22 verapamil, 80 to 640 mg/day (mean 280), 2 nifedipine, 1 diltiazem and amiodarone and 1 isosorbide (15 were receiving additional isosorbide). Twelve patients were not receiving therapy or were receiving very low dosage therapy, including 8 with asymptomatic periods of more than 1 year. Patients with coronary spasm and less than 70% diameter narrowing treated medically have low mortality and morbidity rates over 5-year follow-up. Many have long asymptomatic periods and some may be able to stop therapy indefinitely.

Coronary artery spasm. What is its role in ischemic heart disease?

Knowledge of the pathophysiology of myocardial ischemia has been greatly enhanced recently by new information on coronary artery spasm. This phenomenon accounts for the mechanism underlying the attacks of resting chest pain in Prinzmetal's angina and plays a role in almost all aspects of ischemic heart disease. The diagnosis of coronary artery spasm can be made presumptively with noninvasive methods, but definitive documentation is usually obtained in the cardiac catheterization laboratory. The nitrate derivatives and the calcium antagonists provide a safe and effective approach to therapy.

Nicardipine for angina pectoris at rest and coronary arterial spasm

The antiischemic effects and safety of nicardipine were assessed in 17 patients with angina at rest and coronary arterial spasm in a randomized placebo-controlled study over 8 to 13 weeks. Eleven patients had previously had unsatisfactory results with long-acting nitrates or other calcium blockers. The average daily dosage of nicardipine for optimal angina relief was 89 mg (range 40 to 160). During the double-blind phase, angina frequency decreased with nicardipine compared with placebo (mean 0.47 vs 2.11 attacks/day, p less than 0.05). A similar decrease in nitroglycerin requirements occurred (0.51 vs 2.77 tablets/day, p less than 0.05). During placebo periods, 51 episodes of ischemic ST-segment shifts occurred during 482 hours of ambulatory electrocardiographic monitoring and 12 (24%) were associated with angina. During nicardipine treatment, only 15 episodes of ST-segment shifts occurred during 498 hours of monitoring. In 1 patient a burning skin rash developed; otherwise, the drug was generally well tolerated. Thus, nicardipine is effective and safe in preventing symptomatic and asymptomatic ischemia in patients with coronary spasm. It may be particularly beneficial in patients with unsatisfactory responses to other therapy.

Percutaneous transluminal coronary angioplasty for the treatment of variant angina

Among 268 patients undergoing percutaneous transluminal coronary angioplasty between February 1980 and January 1983, a total of 21 patients had variant angina, documented before angioplasty in 14 and after angioplasty in 7. Before angioplasty, all 21 patients had rest angina and 17 also had effort angina; single vessel coronary artery disease with 60 to 95% stenosis was present in all patients and the left anterior descending coronary artery was involved in all but 3 patients. Coronary angioplasty was successful in 19 patients (90%). Eight of the 19 patients remained symptom-free without coronary restenosis after successful angioplasty; in the other 11 patients, angina reappeared within 4 months, usually in association with restenosis. Of the nine patients with coronary restenosis, six had repeat angioplasty (five successful procedures and one failure), two received medical therapy and one underwent coronary bypass surgery. Patients in whom calcium channel antagonists were discontinued immediately after angioplasty had an exceedingly high coronary restenosis rate (8 [80%] of 10 successful attempts), but when calcium antagonists were continued for an average of 6 +/- 4 months after angioplasty, the restenosis rate was low (3 [21%] of 14 successful attempts). After a mean (+/- SD) follow-up period of 33 +/- 13 months, 1 patient had died and the 20 others (95%) were symptom-free; among these 20, 15 patients (75%) had been taking no antianginal drugs for more than 1 year, 2 still received calcium channel antagonists and 3 had had coronary bypass surgery. Repeat coronary arteriography performed 14 +/- 7 months after angioplasty in the 17 patients without angioplasty-related infarction or surgery showed 50% or less coronary stenosis in 13 patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Large vessel coronary vasospasm: diagnosis, natural history and treatment

The diagnosis of coronary artery spasm is confirmed by angiography, for example, change in caliber of the coronary arteries plus evidence of ischemia. The prevalence and contribution of coronary artery spasm in the individual patient with symptoms of ischemic heart disease is not known and depends on how the condition is defined. The prognosis of patients with coronary artery spasm appears to depend on the presence or absence of severe coronary atherosclerosis, that is, those with severe disease have a worse prognosis. Nitrates should be used to initiate therapy in all patients with this problem. Intravenous nitrates have proven useful in patients whose symptoms are difficult to control and who require hospitalization. beta blockers used alone may be detrimental in patients with coronary artery spasm, but studies supporting the detrimental effects are few. The combination of nitrates, beta blockers and nifedipine has proved effective therapy for many patients with recurrent angina at rest, possibly related to coronary artery spasm. Several open-label and double-blind placebo control trials have shown that all of the calcium antagonists are effective short-term agents for patients with proven coronary artery spasm. When nifedipine was compared with isosorbide dinitrate in a randomized crossover, double-blind trial in patients with coronary artery spasm, both drugs were shown to be efficacious and neither was superior. The traditional alpha-blocking agents have not been shown to be an effective therapy, but a recent study of prazosin, a selective alpha blocker, revealed excellent results in patients whose conditions were resistant to therapy with traditional calcium blockers, beta blockers and, in 1 case, phenoxybenzamine.(ABSTRACT TRUNCATED AT 250 WORDS)

Circadian variation in variant angina

Thirteen hospitalized patients with variant angina were studied to assess circadian variation in disease activity. Over 48 hours, all angina attacks were noted, a continuous Holter electrocardiogram was recorded and 2 ergonovine tests were performed 12 hours apart, 1 at 4 AM and the other at 4 PM. Only 2 patients gave a clearcut history of more frequent nocturnal or early morning attacks. During the study period, 1.8 +/- 1.6 AM and 0.62 +/- 1.2 PM angina episodes per patient were reported (p less than 0.02), but a circadian pattern was apparent in only 4 patients. However, Holter analysis revealed 5.3 +/- 13.8 AM and 2.6 +/- 8.5 PM episodes of ST elevation per patient (p less than 0.05) and 8.1 +/- 13.9 AM and 3.2 +/- 8.5 PM episodes of ST elevation, ST depression or T-wave pseudonormalization (p less than 0.01). Ten of 11 patients with Holter abnormalities had more frequent AM than PM attacks (p less than 0.01). ST elevation developed during all 13 of the 4-AM and 12 of 13 of the 4-PM ergonovine tests. In 10 cases the ergonovine threshold at which the attack occurred was lower in the morning, in no case was it lower in the afternoon, and in 3 patients the morning and afternoon doses were identical (p less than 0.01). Thus, circadian variation in disease activity both for spontaneous and provoked attacks is present in most patients with variant angina, even though it is often not clinically apparent.

What is the long-term prognosis of patients with coronary spasm and normal coronary arteries?

The clinical course of patients with pure coronary artery spasm is variable. Some patients have a chronic course characterized by recurrent angina at rest. Others develop spontaneous remission of symptoms. Most patients have a poor response to long-acting nitrate therapy and a good response to calcium antagonists. Despite the morbidity associated with this syndrome, cardiac mortality is low. When death occurs, it is usually sudden and probably secondary to an arrhythmia.