Spontaneous remission in variant angina

Coronary Vasospastic Angina: A Review of the Pathogenesis, Diagnosis, and Management

Vasospastic angina (VSA) is an under-appreciated cause of chest pain. It is characterised by transient vasoconstriction of the coronary arteries and plays a significant role in the pathogenesis of stable angina and acute coronary syndromes. Complex mechanistic pathways characterised by endothelial dysfunction and smooth muscle hypercontractility lead to a broad spectrum of clinical manifestations ranging from recurrent angina to fatal arrhythmias. Invasive provocation testing using intracoronary acetylcholine or ergonovine is considered the current gold standard for diagnosis, but there is a wide variation in protocols amongst different institutions. Conventional pharmacological therapy relies on calcium channel blockers and nitrates; however, refractory VSA has limited options. This review evaluates the pathophysiology, diagnostic challenges, and management strategies for VSA. We believe global efforts to standardise diagnostic and therapeutic guidelines will improve the outcomes for affected patients.

Percutaneous coronary intervention in patients with documented coronary vasospasm during long-term follow-up

Objective

Although recurring coronary artery spasm (CAS) may lead to the development of fixed atherosclerotic coronary stenosis (FS), the relationship between coronary atherosclerosis and CAS is still speculative. We evaluated the incidence of FS requiring percutaneous coronary intervention (PCI) in patients with documented CAS during long-term follow-up and analysed their clinical features.

Methods

Clinical data of 3556 patients during a median follow-up of 9.4 years after non-invasive ergonovine spasm provocation testing with echocardiographic monitoring of left ventricular wall motion (erg echo) were analysed.

Results

Erg echo documented CAS in 830 (23.3%) patients, who had higher frequencies of coronary risk factors than those without CAS. Patients with documented CAS on erg echo showed significantly lower 10-year overall (90.5% vs 94.2%, p<0.001) and PCI-free (97.4% vs 98.4%, p=0.002) survival rates than those without CAS. Documented CAS was an independent factor associated with later PCI after adjustment by either Cox regression model or Fine-Gray competing risk model. There was no significant difference in baseline clinical characteristics between patients who needed later PCI and those who did not. Among 28 patients who needed later PCI after documentation of CAS, the original CAS and later PCI territory were concordant in 25 (89.3%), while 3 (10.7%) showed discordance.

Conclusions

CAS is a risk factor for the development of FS requiring PCI during long-term follow-up, and warrants physicians’ vigilance and careful follow-up of patients with documented CAS and insignificant stenosis of major epicardial coronary arteries at the time of initial diagnosis.

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.

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.

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.

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)

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.

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.

Spontaneous remission is a frequent outcome of variant angina

To assess the prevalence of spontaneous remission in variant angina, 100 patients with this diagnosis who had undergone coronary arteriography in the hospital and a follow-up of at least 1 year were studied. Patients with coronary bypass surgery or myocardial infarction were excluded. Remission was diagnosed in 45 of the 100 patients who had been angina-free and had had no treatment for more than 3 months (mean 18.3). The other 55 patients were receiving medical treatment; 37 had been angina-free for at least 6 months (mean 22.5) and angina persisted in 18. The persistent angina group had a lower prevalence of organic coronary stenoses 70% or greater: 4 of 18 versus 22 of 45 and 22 of 37 for the other two groups (p less than 0.05), and a longer history of rest angina before admission. The remission group contained more patients (17 of 45 versus 4 of 55 [p less than 0.001]) whose attacks had been documented only by provocative testing. Rest angina recurred when calcium antagonist drugs were discontinued in 15 of 51 instances, within 1 month in 11 patients and later in 4 patients. Remission was eventually attained in 35 of the 38 patients in whom these drugs were stopped. These results indicate that remission is a frequent outcome of variant angina. This fact should be considered in the evaluation of the long-term results of treatment and in the planning of care for an individual patient.

Natural history of pure coronary artery spasm in patients treated medically

The clinical course of 59 patients with coronary artery spasm and no fixed severe coronary obstruction was analyzed for an average of 5.9 years. The study group consisted of 27 men and 32 women. Angina at rest was the predominant symptom in 93% of the patients. Myocardial infarction occurred in 19% and syncope during angina in 27%. During spontaneous anginal episodes, 64% of the patients showed ST segment elevation, 17% ST segment depression and 15% no electrocardiographic changes. Major arrhythmias during angina occurred in 24% of the patients. Permanent pacemakers were required in 10% of the patients. Stress tests were positive in 32% of the patients. Long-acting nitrate therapy controlled symptoms in only 31%, and calcium antagonist agents controlled symptoms in 83% of the patients unresponsive to nitrates. Spontaneous remission of angina for at least 1 month while receiving no medical treatment occurred in 39% of the patients. Fifteen percent of patients had an indefinite remission with no recurrence of symptoms for at least 2 years. There were no cardiac deaths. The natural history of medically treated patients with pure coronary spasm is characterized by recurrent angina at rest, frequent spontaneous remission, a poor response to long-acting nitrate therapy and a good response to calcium antagonists. Although myocardial infarction and major arrhythmias are common, cardiac mortality is low in medically treated patients.

Randomized withdrawal from nifedipine: placebo-controlled study in patients with coronary artery spasm

A multicenter randomized double-blind withdrawal study was conducted to compare the efficacy of nifedipine to that of placebo in vasospastic angina. Following a 2-week single-blind nifedipine baseline period, during which nifedipine was maintained at prestudy levels, 38 patients, 19 taking placebo and 19 continuing nifedipine therapy, either completed a 4-week randomized phase or were prematurely withdrawn because of therapeutic failure. During the randomized phase, an increase in median anginal frequency (2.8 attacks/wk, p less than 0.003) and nitroglycerin usage (0.5 tablets/wk, p less than 0.03) occurred only in the placebo group. The randomized phase was prematurely terminated because of anginal exacerbation in 7 of 19 placebo patients (37%) (only 1 patient receiving nifedipine [p = 0.02] experienced anginal exacerbation). Double-blind therapy was judged effective in 16 patients (84%) receiving nifedipine and in 3 patients (16%) receiving placebo (p less than 0.001). Nifedipine was well tolerated. This study establishes the efficacy of nifedipine in the treatment of variant and validates previous clinical experience.

The hyperventilation test as a method for developing successful therapy in Prinzmetal's angina

In 10 cases of Prinzmetal's angina in which episodes of myocardial ischemia were easily and reproducibly induced by hyperventilation, this test was performed 111 times, 41 times under control conditions and 70 times during treatment with one or more of the following drugs: phentolamine, isosorbide dinitrate, propranolol, verapamil, nifedipine and amiodarone. Seventeen of 18 negative tests performed under the influence of a long-acting drug coincided with total remission of the patient's anginal episodes when this drug was administered on a short- or long-term basis. No patient died or sustained infarction during a follow-up period of 10.9 months. A negative test was thus a good indication that the clinical response to the corresponding drug would be favorable. The electrocardiographic changes and chest pain provoked by hyperventilation occurred not when alkalosis was greatest (hydrogen ion [pH] change from 7.42 to 7.58, p less than 0.001), but when pH was approaching normal or control values. The onset of electrocardiographic changes occurred an average of 175 seconds after the end of hyperventilation and, in two cases, the time lag was as much as 480 and 705 seconds, respectively. This raises several questions regarding the true mechanism triggering coronary spasm under such conditions. The hyperventilation test appears to be a useful and safe procedure for selecting the best possible drug for long-term treatment of Prinzmetal's angina as well as for comparing the relative efficacy of different drugs.