Coronary artery spasm in myocardial infarction

Circadian Distribution of Acute Myocardial Infarction in Different Age Groups

Many epidemiologic studies reported a morning peak in the incidence of acute myocardial infarction (AMI). However, clinical outcomes and the relation between age distribution and circadian pattern have not been fully investigated in a large number of patients. Our study aimed to clarify the impacts of onset time in circadian variation on incidence and clinical outcomes of AMI according to age. From the Korea Acute Myocardial Infarction Registry, we gathered data of 20,685 patients from 53 centers in Republic of Korea. Data from a total of 19,915 patients (11,339 ST elevation myocardial infarction, 8,576 non-ST elevation myocardial infarction) were analyzed from the registry, after exclusion of diagnoses other than AMI. A morning-dominant incidence was shown by sinusoidal function, in all patients and in all separate age groups (age < 55, 55 ≤ age < 75, 75 ≤ age). In-hospital mortality and major adverse cardiovascular events (MACEs), including cardiac deaths, noncardiac deaths, recurrent myocardial infarction, repeated percutaneous coronary intervention, and coronary artery bypass graft at 1, 12, and 24 months' follow-up, were compared in 4 periods (00:00~05:59, 06:00~11:59, 12:00~17:59, and 18:00~23:59), and no significant difference was noted. Kaplan-Meier curve was drawn for death and MACE-free survival, and no significant different event-free survival was depicted (p value = 0.31). In conclusion, the incidences of myocardial infarction by onset time were uneven in 24 hours, in all patients and age groups, by sinusoidal function. However, there were no significant differences in in-hospital mortality or MACEs in the 4 time periods during 24 months of follow-up.

Blunted heart rate recovery is associated with coronary artery spasm in patients with suspected vasospastic angina

Background

Autonomic nervous system activity has been shown to be altered in patients with vasospastic angina (VA). Heart rate recovery (HRR) is a simple, non-invasive measurement of autonomic nervous system dysfunction. We aimed to investigate whether HRR is related to VA, as established by an ergonovine test.

Methods

A total of 976 consecutive patients (47.5% male, mean age 55 years) without significant coronary artery disease who underwent both an ergonovine provocation test and a treadmill exercise test were enrolled. The relationship between VA and HRR was evaluated.

Results

A total of 30.7% (300/976) of patients were diagnosed with VA, as documented by the ergonovine provocation test. HRR was significantly reduced in patients with VA compared to patients without VA (24.6 ± 18.0 vs. 30.5 ± 22.2, p < 0.001), and HRR was lowest in patients with multi-vessel spasm (21.9 ± 17.3). The proportion of blunted HRR, which was defined as HRR less than 12 beats, was significantly higher in patients with VA than in those without coronary artery spasm (26.6% vs. 39.3%, p < 0.001). In multivariable regression analyses, age (odds ratio (OR) = 1.03; 95% confidence interval (CI): 1.01–1.04; p = 0.001), blunted HRR (OR = 1.71; 95% CI: 1.26–2.31; p < 0.001), current smoking status (OR = 2.11; 95% CI: 1.50–2.98; p < 0.001), and male gender (OR = 2.00; 95% CI: 1.43–2.78; p < 0.001) were significant independent predictors of VA presence.

Conclusion

Blunted HRR was an independent predictor of VA presence, which suggests a link between coronary artery spasm and autonomic dysregulation.

The Impact of Subclinical Hypothyroidism or Thyroid Autoimmunity on Coronary Vasospasm in Patients without Associated Cardiovascular Risk Factors

Background and Objectives

Subclinical hypothyroidism is associated with endothelial dysfunction and impaired coronary flow reserve. However, the effect of subclinical hypothyroidism or thyroid autoimmunity on variant angina has yet to be determined.

Subjects and Methods

Among 385 consecutive patients without associated cardiovascular risk factors who underwent coronary angiography with the ergonovine provocation test (EPT), 165 had a positive EPT {EPT(+)} and 220 had a negative EPT {EPT(-)}. The relationship between coronary artery spasm and the presence of subclinical thyroid dysfunction as well as serum thyroid peroxidase autoantibody (TPO Ab) was evaluated.

Results

The proportion of patients with subclinical hypothyroidism among those who were EPT(+) was significantly higher than that in those who were EPT(-) (18% vs. 11%, p=0.001). However, there was no significant difference in the proportion of patients with subclinical hyperthyroidism between the groups. Moreover, EPT(+) patients showed significantly more positive TPO Ab (33% vs. 14%, p<0.001) than those with EPT(-). There was a positive correlation between EPT(+) and TPO positivity (r=0.226, p<0.001), subclinical hypothyroidism (r=0.112, p=0.033), and body mass index (r=0.123, p=0.018). Binary logistic regression analysis revealed that the significant predictors of EPT(+) were body mass index {adjusted odds ratio (OR)=1.042, 95% confidence interval (CI)=1.005-1.080}, presence of subclinical hypothyroidism (OR=3.047, 95% CI=1.083-8.572), TPO Ab titer (OR=1.028, 95% CI=1.015-1.041), and the presence of TPO Ab (OR=4.904, 95% CI=1.544-15.567).

Conclusion

Subclinical hypothyroidism and the presence of TPO Ab are significantly associated with coronary vasospasm in patients without cardiovascular risk factors.

Chronic kidney disease stage is a modulator on the association between high-sensitivity C-reactive protein and coronary vasospastic angina

The prevalence of coronary vasospasm and also the factors associated with coronary vasospasm in CKD is still unclear. In this cross-sectional study of 859 consecutive CKD patients with angina pectoris received coronary catheterization, we evaluated the factors associated with coronary vasospasm. Patients with vasospasm were older and had higher peripheral blood white cell counts, higher peripheral blood monocyte cell counts, higher haemoglobin levels, higher hs-CRP levels, and lower levels of serum creatinine than patients without vasospasm. The results of multivariate logistic regression analysis revealed that peripheral blood monocyte count and hs-CRP level were independently associated with coronary vasospasm in patients with stage 1 CKD. Only peripheral blood monocyte count but not hs-CRP was independently associated with coronary vasospasm in patients with stages 2 and 3 of CKD. In conclusion, peripheral blood monocyte count is independently associated with coronary vasospasm in patients with stage 1–3 CKD, whereas hs-CRP is only independently associated with coronary vasospasm in patients with stage 1 CKD.

Higher serum uric acid and lipoprotein(a) are correlated with coronary spasm

It has been reported that a major cause of coronary vasospastic angina (VSA) is endothelial dysfunction of the coronary artery. On the other hand, some studies showed that serum uric acid and lipoprotein(a) are correlated with endothelial dysfunction. Thus, we examined whether uric acid and lipoprotein(a), are correlated with VSA. Four hundred forty-one patients with suspected VSA who underwent a coronary angiogram with acetylcholine provocation (ACh test) during an 8-year period were enrolled. We divided them into a VSA group, who showed coronary spasm by the ACh test, and an atypical chest pain (ACP) group, who showed negative ACh test. We compared serum markers between the two groups, including low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, high-sensitivity C-reactive protein (hs-CRP), lipoprotein(a), fibrinogen, total plasminogen activator inhibitor-1, and uric acid. Uric acid, hs-CRP, and lipoprotein(a) were significantly higher in the VSA group than in the ACP group (all P < 0.05) while there were no significant differences in the other parameters. Multivariate analyses identified uric acid and lipoprotein(a) as significant independent markers for VSA. Uric acid and lipoprotein(a) are correlated with VSA, and medical intervention to decrease uric acid and lipoprotein(a) might be effective in controlling VSA.

Low glomerular filtration rate is associated with high prevalence of vasospastic angina

BACKGROUND

Although chronic kidney disease is associated with a high prevalence of cardiovascular disease, the relationship between coronary artery spasm and renal dysfunction has not been elucidated.

METHODS AND RESULTS

We evaluated 139 patients with chest pain at rest who had no significant organic stenosis on coronary angiograms and who underwent coronary spasm provocation tests using acetylcholine or ergonovine. The results of the provocation tests revealed that 59 patients had vasospastic angina (VSA), and that 80 did not (non-VSA). We analyzed the association between VSA and renal dysfunction using the estimated glomerular filtration rate (eGFR). The eGFR was significantly lower in the VSA group than in the non-VSA group (P = 0.013). The patients were assigned to quartiles (Q) 1, 2, 3 and 4 based on eGFR (ml·min⁻¹·1.73 m²) < 64.1, 64.1-74.7, 74.8-85.0 and ≥ 85.1, respectively, in each of which the prevalence of VSA was 57%, 53%, 34% and 26%, respectively. The prevalence of VSA was significantly higher in Q1 than in Q4 (P = 0.008). Logistic regression analysis showed that the independent factors associated with the presence of VSA were a lower eGFR (P = 0.011) and male gender (P = 0.001).

CONCLUSIONS

Lower levels of eGFR in our study population were significantly and independently associated with a high prevalence of VSA, suggesting that a lower eGFR could be a risk factor for VSA.

Decreased plasma extracellular superoxide dismutase level in patients with vasospastic angina

OBJECTIVE

Extracellular superoxide dismutase (EC-SOD) is the major extracellular scavenger of superoxides, and one of the main regulators of nitric oxide bioactivity in vessel walls. Here, we examined whether plasma EC-SOD level was associated with vasospastic angina (VSA), and if it was a risk factor for VSA.

METHODS AND RESULTS

We assigned 105 patients with normal or mildly stenotic coronary arteries into either a VSA (n=58) or chest pain syndrome (CPS) (n=47) groups. Plasma EC-SOD and other biochemical variables were measured, and major coronary risk factors were assessed. Results showed that apart from smoking status there were no significant differences in patient characteristics and biochemical variables between the two groups. In the VSA group, prevalence of smoking was significantly higher (53% versus 26%, p=0.0055), and plasma EC-SOD level was significantly lower (68.9+/-18.5 ng/ml versus 83.8+/-25.9 ng/ml; p=0.0009). Not only smoking (OR 2.742, 95% CI 1.032-7.287, p=0.0431) but also plasma EC-SOD (OR 0.971, 95% CI 0.949-0.993, p=0.0102) was an independent risk factor for VSA.

CONCLUSIONS

In patients with VSA, plasma EC-SOD level was substantially reduced. Furthermore, plasma EC-SOD level followed by cigarette smoking was the most predictive risk factor for coronary spasms.

Prevention of Ventricular Fibrillation, Acute Myocardial Infarction (Myocardial Necrosis), Heart Failure, and Mortality by Bretylium

It is widely, but mistakenly, believed that ischemic heart disease (IsHD) and its complications are the sole and direct result of reduced coronary blood flow by obstructive coronary artery disease (CAD). However, cardiac angina, acute myocardial infarction (AMI), and sudden cardiac death (SCD) occur in 15%-20% of patients with anatomically unobstructed and grossly normal coronaries. Moreover, severe obstructive coronary disease often occurs without associated pathologic myocardiopathy or prior symptoms, ie, unexpected sudden death, silent myocardial infarction, or the insidious appearance of congestive heart failure (CHF). The fact that catecholamines explosively augment oxidative metabolism much more than cardiac work is generally underappreciated. Thus, adrenergic actions alone are likely to be more prone to cause cardiac ischemia than reduced coronary blood flow per se. The autonomic etiology of IsHD raises contradictions to the traditional concept of anatomically obstructive CAD as the lone cause of cardiac ischemia and AMI. Actually, all the signs and symptoms of IsHD reflect autonomic nervous system imbalance, particularly adrenergic hyperactivity, which may by itself cause ischemia as in rest angina. Adrenergic activity causing ischemia signals cardiac pain to pain centers via sympathetic efferent pathways and tend to induce arrhythmogenic and necrotizing ischemic actions on the cardiovascular system. This may result in ischemia induced metabolic myocardiopathy not unlike that caused by anatomic or spasmogenic coronary obstruction. The clinical study and review presented herein suggest that adrenergic hyperactivity alone without CAD can be a primary cause of IsHD. Thus, adrenergic heart disease (AdHD), or actually adrenergic cardiovascular heart disease (ACVHD), appears to be a distinct entity, most commonly but not necessarily occurring in parallel with CAD. CAD certainly contributes to vulnerability as well as the progression of IsHD. This vicious cycle, which explains the frequent parallel occurrence of arteriosclerosis and IHD, an association that appears to be linked by the same cause, comprises a common vulnerability to deleterious adrenergic actions on the myocardium, lipid metabolism, and vascular system alike, rather than viewing CAD and IsHD as having a putative cause and effect relationship as commonly thought. Adrenergic actions can also cause the abnormal lipid metabolism that is associated with CAD and IsHD by catecholamine-induced metabolic actions on lipid mobilization by activation of phospholipases. This may also be part of toxic catecholamine hypermetabolic actions by enhancing deleterious cholesterol and lipid actions in damaging coronary vessels by plaque formation as well as inducing obstructive coronary spasm and platelet aggregation. This may also cause direct toxic necrosis on the myocardium as well as atherosclerosis in blood vessels. In fact, drugs that inhibit adrenergic actions like propranolol, reserpine, and guanethidine all inhibit arteriosclerosis induced by hypercholesterolemia in experimental animals and prevent carotid vascular disease (associated with stroke) in humans. The concomitant development of myocardiopathy and coronary vascular lesions or coronary and carotid artery intimal medial thickening by catecholamine toxicity is reflected by the frequent primary presentation of patients with catecholamine-secreting pheochromocytoma with cardiovascular disease, ie, hypertension arrhythmias, AMI, SCD, CHF, and vascular disease, which represents a clear example of the primary deleterious impact of catecholamines on the entire cardiovascular system causing adrenergic cardiovascular disease. Thus, like myocardiopathy, CAD and atherosclerosis in general may be the consequences of or a complication of catecholamine actions rather than its putative cause. This report shows how prophylactic bretylium not only prevents arrhythmias but prevents myocardial necrosis, shock, CHF, maintains or restores normal contractility, and lowers mortality in AMI patients by inducing adrenergic blockade.