Plaque Morphology at Coronary Sites With Focal Spasm in Variant Angina-Study Using Intravascular Ultrasound-

Clinical Characteristics and Major Adverse Cardiovascular Events in Diabetic and Non-Diabetic Patients with Vasospastic Angina

Purpose

The clinical background and prognostic impact of diabetes mellitus (DM) on vasospastic angina (VSA) are unclear; thus, in this retrospective study, we investigated whether they differ based on the presence or absence of DM in patients with VSA.

Patients and Methods

We included 272 Japanese patients with VSA diagnosed by coronary angiography (CAG) and the spasm provocation test (SPT). The diagnosis of DM was determined by measuring fasting blood glucose and hemoglobin A1C and by the patient's current oral medications. On CAG, the presence of atherosclerotic lesions (20%-50%) was checked. On SPT, the coronary spasm was defined as transient coronary vasoconstriction >90% on CAG, accompanied by chest symptoms and/or ST-T changes. Focal spasm was defined as coronary spasm occurring within one segment of the American Heart Association classification on CAG. Blood and urine tests and vascular endothelial function were also evaluated when possible. A major adverse cardiovascular event (MACE), which is defined as cardiac mortality and rehospitalization due to cardiovascular illness, was the basis for determining the prognosis.

Results

There were 49 patients (18%) in the DM group and 223 (82%) in the non-DM group. No significant differences in urinary albumin levels and peripheral vascular function were between groups. On CAG, atherosclerotic lesions were observed significantly more frequently in the DM group (63% vs 46%; P = 0.028). Results of SPT showed a trend toward fewer focal spasms in the DM group (24% vs 39%; P = 0.072). No significant differences in MACE were noted between groups in the primary analysis of DM, whereas sub-analyses of focal spasms showed lower MACE-free survival in the DM group (P = 0.042).

Conclusion

The study results support the hypothesis that DM associated with VSA should be treated appropriately, especially in cases of focal spasm, which may require more attention in treatment.

Coronary Spasm: Ethnic and Sex Differences

Coronary spasm (CS), which may occur at the epicardial (focal or diffuse spasm) and/or microvascular (microvascular spasm) level, is a well-established cause of myocardial ischaemia, in particular in patients with anginal chest pain despite unobstructed coronary arteries. The diagnosis of CS can be confirmed during coronary angiography by an additional provocation test with vasoactive substances such as acetylcholine. Due to partially inconsistent data from large clinical studies, especially between Asian and white CS patients, ethnic differences concerning the prevalence and angiographic patterns of CS seem to exist. Furthermore, several studies in patients with coronary vasomotor disorders pointed towards differences among male and female CS patients. This article gives an overview of ethnic- and sex-related differences in patients with CS.

Does the intracoronary pressure differ according to two types (diffuse or focal) of coronary spasm?

BACKGROUND

Several reports show that two types of coronary vasospasm (diffuse and focal spasm) are associated with the severity or prognosis of coronary spasm in patients with vasospastic angina (VSA). It is unclear whether intracoronary pressure differs between the two spasm types.

AIM

To investigate such relationships using a pressure wire during the spasm provocation test (SPT) in patients with VSA.

METHODS

Eighty-seven patients with VSA (average age: 67 years; 50 men, 37 women) underwent SPT. During the SPT, a pressure wire was advanced into the distal portion of the right coronary artery and left anterior descending coronary artery, and the ratio of the intracoronary pressure to the aortic pressure (Pd/Pa) was continuously monitored. An SPT was performed using acetylcholine (ACh), and the presence of coronary spasm was defined as the presence of > 90% arterial narrowing in response to an ACh infusion, with the usual chest symptoms and/or ischemic ECG changes. Focal spasm was defined as total or subtotal spasm within one segment of the AHA classification, while diffuse spasm was defined as > 90% spasm with two or more segments.

RESULTS

Among 87 patients, the frequencies of metabolic syndrome and having coronary atherosclerosis were higher in the focal group (n = 33) than in the diffuse spasm group (n = 54, P < 0.05). In the vessel analyses, in these 134 spastic segments, diffuse and focal spasms were detected in 100 and 34 vessels, respectively. The Pd/Pa at baseline was similar in both groups (diffuse: 0.96 ± 0.05, focal: 0.95 ± 0.05, P = 0.35); however, the Pd/Pa during coronary spasm was lower in focal spastic vessels (0.66 ± 0.20) than in diffuse spastic vessels (0.76 ± 0.11, P < 0.01), and the reduction in Pd/Pa during an SPT was also lower in focal spastic vessels (-0.29 ± 0.20) than in diffuse spastic vessels (-0.18 ± 0.11, P < 0.01). The presence of focal spasm was a significant factor responsible for reduction in Pd/Pa during SPT.

CONCLUSION

These findings suggest that focal spasm may be more severe than diffuse spasm, judging from the intracoronary pressure during coronary spasm.

Intracoronary Thrombogenicity in Patients with Vasospastic Angina: An Observation Using Coronary Angioscopy

BACKGROUND

Despite significant interest in intracoronary thrombi in patients with vasospastic angina (VSA), the phenomenon remains unclarified. Therefore, we investigated a possible relationship using coronary angioscopy (CAS) in VSA patients.

METHODS

Sixty patients with VSA, for whom we could assess the spastic segment using CAS, were retrospectively studied. An intracoronary thrombus on CAS was a white thrombus and an erosion-like red thrombus. We verified the clinical characteristics and lesional characteristics as they determined the risk of intracoronary thrombus formation.

RESULTS

There were 18 (30%) patients with intracoronary thrombi. More of the patients with intracoronary thrombi were male, current smokers and had severe concomitant symptoms; however, no statistically significant difference was observed upon logistic regression analysis. There were 18 (26%) coronary arteries with intracoronary thrombi out of 70 coronary arteries recognised in the spastic segments. Furthermore, atherosclerotic changes and segmental spasms were significant factors responsible for such lesions.

CONCLUSION

Intracoronary thrombi occurred in 30% of VSA patients and much attention should be paid to the intracoronary thrombogenicity of VSA patients.

Clinical use of intracoronary imaging. Part 2: acute coronary syndromes, ambiguous coronary angiography findings, and guiding interventional decision-making: an expert consensus document of the European Association of Percutaneous Cardiovascular Interventions

This consensus document is the second of two reports summarizing the views of an expert panel organized by the European Association of Percutaneous Cardiovascular Interventions (EAPCI) on the clinical use of intracoronary imaging including intravascular ultrasound (IVUS), optical coherence tomography (OCT), and near infrared spectroscopy (NIRS)-IVUS. Beyond guidance of stent selection and optimization of deployment, invasive imaging facilitates angiographic interpretation and may guide treatment in acute coronary syndrome. Intravascular imaging can provide additional important diagnostic information when confronted with angiographically ambiguous lesions and allows assessment of plaque morphology enabling identification of vulnerability characteristics. This second document focuses on useful imaging features to identify culprit and vulnerable coronary plaque, which offers the interventional cardiologist guidance on when to adopt an intracoronary imaging-guided approach to the treatment of coronary artery disease and provides an appraisal of intravascular imaging-derived metrics to define the haemodynamic significance of coronary lesions.

Coronary Artery Spasm: New Insights

Coronary artery spasm (CAS) defined by a severe reversible diffuse or focal vasoconstriction is the most common diagnosis among INOCA (ischemia with no obstructive coronary artery disease) patients irrespective to racial, genetic, and geographic variations. However, the prevalence of CAS tends to decrease in correlation with the increasing use of medicines such as calcium channel blockers, angiotensin converting enzyme inhibitor, and statins, the controlling management of atherosclerotic risk factors, and the decreased habitude to perform a functional reactivity test in highly active cardiac catheterization centers. A wide spectrum of clinical manifestations from silent disease to sudden cardiac death was attributed to this complex entity with unclear pathophysiology. Multiple mechanisms such as the autonomic nervous system, endothelial dysfunction, chronic inflammation, oxidative stress, and smooth muscle hypercontractility are involved. Regardless of the limited benefits proffered by the newly emerged cardiac imaging modalities, the provocative test remains the cornerstone diagnostic tool for CAS. It allows to reproduce CAS and to evaluate reactivity to nitrates. Different invasive and noninvasive therapeutic approaches are approved for the management of CAS. Long-acting nondihydropyridine calcium channel blockers are recommended for first line therapy. Invasive strategies such as PCI (percutaneous coronary intervention) and CABG (coronary artery bypass graft) have shown benefits in CAS with significant atherosclerotic lesions. Combination therapies are proposed for refractory cases.

Clinical use of intracoronary imaging. Part 2: acute coronary syndromes, ambiguous coronary angiography findings, and guiding interventional decision-making: an expert consensus document of the European Association of Percutaneous Cardiovascular Interventions

This consensus document is the second of two reports summarizing the views of an expert panel organized by the European Association of Percutaneous Cardiovascular Interventions (EAPCI) on the clinical use of intracoronary imaging including intravascular ultrasound (IVUS), optical coherence tomography (OCT), and near infrared spectroscopy (NIRS)-IVUS. Beyond guidance of stent selection and optimization of deployment, invasive imaging facilitates angiographic interpretation and may guide treatment in acute coronary syndrome. Intravascular imaging can provide additional important diagnostic information when confronted with angiographically ambiguous lesions and allows assessment of plaque morphology enabling identification of vulnerability characteristics. This second document focuses on useful imaging features to identify culprit and vulnerable coronary plaque, which offers the interventional cardiologist guidance on when to adopt an intracoronary imaging-guided approach to the treatment of coronary artery disease and provides an appraisal of intravascular imaging-derived metrics to define the haemodynamic significance of coronary lesions.

Two-dimensional myocardial deformation in coronary vasospasm-related Takotsubo cardiomyopathy: A case report of a serial echocardiographic study

RATIONALE

Although transient reduction in the left ventricular ejection fraction is characteristic of Takotsubo cardiomyopathy, little is known about the time-course changes of myocardial deformation in coronary vasospasm-related Takotsubo cardiomyopathy.

PATIENT CONCERNS

We retrospectively analyzed the time-course changes in left ventricle, right ventricle, and left atrium strain values in a patient with coronary vasospasm-related Takotsubo cardiomyopathy. We found that not only left ventricular strain but also left atrial strain was abnormal during acute Takotsubo cardiomyopathy due to coronary vasospasm. Right ventricular free wall strain was normal.

DIAGNOSES

Coronary vasospasm-related Takotsubo cardiomyopathy.

INTERVENTIONS

A serial echocardiographic study.

OUTCOMES

The left ventricular strain was still subnormal despite a normalized left ventricular ejection fraction 2 months later. The left atrial strain was normal when the left ventricular ejection fraction normalized.

LESSONS

From this limited experience, it is suggested that echocardiographic myocardial deformation analysis can provide more information than the standard ejection fraction in evaluating myocardial contractile function.

Noninvasive Tissue Characterization of Coronary Arterial Plaque by 16-Slice Computed Tomography in Acute Coronary Syndrome

Noninvasive characterization of coronary plaques is challenging for cardiologists. The authors’ goal was to explore the clinical feasibility of newly developed 16-slice computed tomography (CT) in tissue characterization of coronary arterial plaques in patients with acute coronary syndrome. Sixteen patients with acute coronary syndrome underwent 16-slice CT (Aquillion, Toshiba) and coronary arteriography with intravascular ultrasound (IVUS) within 7 days. Twenty-three plaques were classified by IVUS according to plaque echogenicity: 6 soft plaques, 11 intermediate plaques, and 6 calcified plaques. Mean (±SD) CT numbers (Hounsfield units [HU]) of these 3 types of plaques were 50.6 ±14.8 HU, 131 ±21.0 HU, and 721 ±231 HU, respectively. Sixteen-slice CT facilitates noninvasive tissue characterization of coronary arterial plaques.

Clinical features and prognosis of patients with coronary spasm-induced non-ST-segment elevation acute coronary syndrome

BACKGROUND

The prevalence, clinical features, and long-term outcome of patients with non-ST-segment elevation acute coronary syndrome (NSTE ACS) associated with coronary spasm are not fully investigated.

METHODS AND RESULTS

This observational multicenter study enrolled 1601 consecutive patients with suspected NSTE-ACS who underwent cardiac catheterization between January 2001 and December 2010. A culprit lesion was found in 1152 (72%) patients. In patients without a culprit lesion, the acetylcholine provocation test was performed in 221 patients and was positive in 175 patients. In the other patients, coronary spasm was verified in 145 patients during spontaneous attack. Spasm-induced NSTE-ACS was diagnosed in 320 (20%) patients. Multivariable analysis identified age <70 years (odds ratio [OR] 2.19, 95% CI 1.58 to 3.04), estimated glomerular filtration rate >60 mL/min per 1.73 m(2) (OR 1.72, 95% CI 1.16 to 2.56), and lack of hypertension (OR 2.55, 95% CI 1.90 to 3.41), dyslipidemia (OR 2.76, 95% CI 2.05 to 3.73), diabetes mellitus (OR 2.49, 95% CI 1.78 to 3.48), previous myocardial infarction (OR 5.37, 95% CI 2.89 to 10.0), and elevated cardiac biomarkers (OR 2.84, 95% CI 2.11 to 3.83) as significant correlates of spasm-induced NSTE-ACS (P<0.01 for all variables). Transient ST-segment elevation during spontaneous attack (variant angina) was observed in 119 patients with spasm-induced NSTE-ACS. Variant angina was more common in nondyslipidemic men among patients with spasm-induced NSTE-ACS.

CONCLUSIONS

The study showed frequent involvement of coronary spasm in the pathogenesis of NSTE-ACS. Variant angina was observed in one third of patients with spasm-induced NSTE-ACS. Coronary spasm should be considered even in patients with less coronary risk factors and nonobstructive coronary arteries.

Clinical usefulness, angiographic characteristics, and safety evaluation of intracoronary acetylcholine provocation testing among 921 consecutive white patients with unobstructed coronary arteries

BACKGROUND

Coronary spasm can cause myocardial ischemia and angina in patients with and those without obstructive coronary artery disease. However, provocation tests using intracoronary acetylcholine administration are rarely performed in clinical routine in the United States and Europe. Thus, we assessed the clinical usefulness, angiographic characteristics, and safety of intracoronary acetylcholine provocation testing in white patients with unobstructed coronary arteries.

METHODS AND RESULTS

From September 2007 to June 2010, a total of 921 consecutive patients (362 men, mean age 62±12years) who underwent diagnostic angiography for suspected myocardial ischemia and were found to have unobstructed coronary arteries (no stenosis ≥50%) were enrolled. The intracoronary acetylcholine provocation testing was performed directly after angiography according to a standardized protocol. Three hundred forty-six patients (35%) reported chest pain at rest, 222 (22%) reported chest pain on exertion, 238 (24%) reported a combination of effort and resting chest pain, and 41 (4%) presented with troponin-positive acute coronary syndrome. The overall frequency of epicardial spasm (>75% diameter reduction with angina and ischemic ECG shifts) was 33.4%, and the overall frequency of microvascular spasm (angina and ischemic ECG shifts without epicardial spasm) was 24.2%. Epicardial spasm was most often diffuse and located in the distal coronary segments (P<0.01). No fatal or irreversible nonfatal complications occurred. However, 9 patients (1%) had minor complications (nonsustained ventricular tachycardia [n=1], fast paroxysmal atrial fibrillation [n=1], symptomatic bradycardia [n=6], and catheter-induced spasm [n=1]).

CONCLUSIONS

Epicardial and microvascular spasm are frequently found in white patients with unobstructed coronary arteries. Epicardial spasm is most often diffuse and located in the distal coronary segments. The intracoronary acetylcholine provocation test is a safe technique to assess coronary vasomotor function.

Coronary plaque component in patients with vasospastic angina: a virtual histology intravascular ultrasound study

BACKGROUND

Coronary spasm plays an important role in the pathogenesis of ischemic heart disease. However, tissue components of coronary plaque in patients with vasospastic angina (VSA) have been unknown. This study used virtual histology (VH)-intravascular ultrasound (IVUS) to elucidate the tissue component of spastic coronary arteries and its gender differences in patients with VSA.

METHODS

According to acetylcholine provocation tests, the study subjects (42 patients [19 men, 23 women, 61 ± 13 years]) were divided into 2 groups: the VSA group of 26 patients and the non-VSA group of 16 patients. After nitrate injection, IVUS volumetric analysis was done, and the parameters were compared between the groups.

RESULTS

Although clinical demographics were almost identical between the groups, VSA group had lower plasma adiponectin level (5.9 ± 3.3 μg/ml vs. 11.2 ± 7.6 μg/ml, p=0.007) and tended to have higher high-sensitivity C-reactive protein (0.15 ± 0.24 mg/dl vs. 0.06 ± 0.04 mg/dl, p=0.1) than non-VSA group. VSA group had diffusely thickened intima (% plaque volume, 34 ± 11% vs. 27 ± 7%, p=0.01) compared with non-VSA group. However, plaque components of patients with VSA were similar with that of non-VSA patients (dense calcium, 4 ± 6% vs. 3 ± 4%; necrotic core, 10 ± 9% vs. 8 ± 6%; fibrofatty, 19 ± 16% vs. 22 ± 11%; and fibrous, 67 ± 16% vs. 67 ± 9%). Although male patients with VSA had atherogenic lipid and metabolic profiles than female VSA patients, there were no significant gender differences in the volumetric IVUS parameters and plaque components.

CONCLUSIONS

Compared with non-VSA patients, VSA patients had diffusely thickened fibrous-dominant coronary plaque without gender difference, and that might suggest the role of vasospasm in the development of atherosclerosis.

A cataclasm due to spasm

We describe a 59-year-old patient presenting with ST-elevation acute coronary syndrome. Coronary angiography with intravascular ultrasound (IVUS) showed an important nonsignificant atherosclerotic lesion in the proximal left anterior descending artery (LAD) and presence of bridging in the mid-LAD. Our hypothesis was that focal spasm at this site was the cause of transmural ischaemia; therefore, treatment was given by performing a percutaneous coronary intervention (PCI) of the lesion. The patient remained symptom-free which confirmed our conclusion. The myocardial bridging had no clinical implications at this moment.

Coronary vasospastic angina: assessment by multidetector CT coronary angiography

Objective

We aimed to describe the imaging findings of multidetector CT coronary angiography (MDCTA) in cases of vasospastic angina (VA) and to determine the accuracy of MDCTA in the identification of VA as compared with invasive coronary angiography with an ergonovine provocation test (CAG with an EG test).

Materials and Methods

Fifty-three patients with clinically suspected VA were enrolled in this study. Two radiologists analyzed the stenosis degree, presence or absence of plaque, plaque composition, and a remodeling index of the related-segment in CAG with an EG test, which were used as a gold standard. We evaluated the diagnostic performances of MDCTA by comparing the MDCTA findings with those of CAG with an EG test.

Results

Among the 25 patients with positive CAG with an EG test, all 12 patients with significant stenosis showed no definite plaque with the negative arterial remodeling. Of the six patients with insignificant stenosis, three (50%) had non-calcified plaque (NCP), two (33%) had mixed plaque, and one (17%) had calcified plaque. When the criteria for significant stenosis with negative remodeling but no definite evidence of plaque as a characteristic finding of MDCTA were used, results showed sensitivities, specificities, positive predictive values (PPV), and negative predictive values (NPV) of 48%, 100%, 100%, and 68%, respectively.

Conclusion

Significant stenosis with negative remodeling, but no definite evidence of plaque, is the characteristic finding on MDCTA of VA. Cardiac MDCTA shows good diagnostic performance with high specificity and PPV as compared with CAG with an EG test.

Acute myocardial infarction caused by multivessel coronary spasm due to calcium channel blocker withdrawal

Calcium channel blockers are a commonly used class of medications for the management of hypertension, angina, and superventricular tachyarrhythmias. Abrupt withdrawal of these agents can precipitate coronary vasospasm, which may result in myocardial infarction. We present the case of a 47-year-old woman who sustained an acute myocardial infarction mediated by multivessel coronary vasospasm secondary to verapamil withdrawal and the associated interventional management.

Functional medial thickening and folding of the internal elastic lamina in coronary spasm

Although there are a number of studies on vasospastic angina, the structural changes at the cellular level that occur in the coronary arterial wall during spasm are not well known. Coronary spasm was induced by brushing the coronary adventitia in nine anesthetized beagles, and structural changes in the spastic coronary segments were examined by light and electron microscopy, making comparisons with the adjacent nonspastic segments. The % diameter stenosis of the spastic segments as measured angiographically was 79.4±12% (mean±SD). Light microscopic changes in the spastic and nonspastic segments were as follows: medial thickness 1,512 vs. 392 μm (P<0.0001) and % diameter and % area stenoses of spastic segment 81.0% and 96.5%, respectively, indicating that spasm was induced by medial thickening. Circular smooth muscle cells (SMCs) in the media were arranged in parallel with the internal (IEL) and external (EEL) elastic lamina in nonspastic segments but radially rearranged in spastic segments. SMCs were classified by their patterns of connection to IEL into six types by electron microscopy. Of these, three contracted and pulled the IEL toward the EEL, causing folding of the IEL and waving of EEL resulting in thickening of the media and narrowing of the lumen. We conclude that coronary spasm was elicited by radial rearrangement of the medial SMCs due to their own contraction and resultant medial thickening and folding of IEL, creating a piston effect to narrow the lumen, i.e., spasm.

Morphological features of coronary arteries in patients with coronary spastic angina: assessment with intracoronary optical coherence tomography

BACKGROUND

Coronary spasm (CS) plays an important role in the pathogenesis of many types of ischemic heart disease, but morphological appearance of non-stenotic coronary segments with CS is not fully understood. We evaluate the morphological characteristics of coronary arteries in patients with coronary spastic angina (CSA) using intravascular optical coherence tomography (OCT).

METHODS

We evaluated 37 patients with resting chest pain whose coronary angiograms did not reveal significant stenosis. These patients underwent an acetylcholine (ACh) provocation test. OCT was performed after complete dilatation of coronary arteries, and additionally during ACh-induced CS in four patients.

RESULTS

Based on the ACh test, 23 patients were diagnosed as having CSA, and the remaining 14 patients without CS were referred to as CS-negative. OCT study revealed that coronary segments with ACh-induced CS had homogeneous intimal thickening, and quantitative analysis showed that CS-positive segments had a significantly greater intima area as compared with corresponding CS-negative segments without lipid or calcium content. By contrast, CS-positive segments had a significantly smaller intima area as compared with CS-negative segments with lipid or calcium deposit. During ACh-induced CS, lumen and total vascular areas were significantly decreased, whereas intima area did not change in comparison with complete vasodilatation. The luminal surface of the intima formed a markedly wavy configuration during CS.

CONCLUSIONS

Coronary artery segments involved in CS are characterized by diffuse intimal thickening without lipid or calcium content. High-resolution coronary OCT imaging could make it possible to analyze the vascular pathophysiology in patients with CS.

Plaque components at coronary sites with focal spasm in patients with variant angina: virtual histology-intravascular ultrasound analysis

BACKGROUND

We compared the plaque components at coronary sites with focal spasm after ergonovine provocation test in 30 variant angina (VA) patients with those at culprit coronary sites in 32 unstable angina (UA) patients using virtual histology-intravascular ultrasound (VH-IVUS).

METHODS

VH-IVUS classified and color-coded tissue into four major components: fibrotic; fibro-fatty; dense calcium (DC); and necrotic core (NC). Thin-cap fibroatheroma (TCFA) was defined as a NC≥10% of plaque area in at least 3 consecutive frames without overlying fibrous tissue in the presence of ≥40% plaque burden.

RESULTS

The lesion site plaque burden was significantly smaller (44.5±10.8% vs. 70.5±13.1%, p<0.001), the plaque volume was significantly smaller (135±118 mm³ vs. 223±160 mm³, p=0.020), the remodeling index was significantly lower (0.90±0.14 vs. 0.97±0.23, p=0.023), and more plaque was hypoechoic with less calcium (87% vs. 56% and 0% vs. 19%, respectively, p=0.033) in VA patients compared with UA patients. The % NC and DC areas were significantly smaller at the minimum lumen site within spasm/culprit lesion (12.9±12.9% vs. 22.3±11.7%, p=0.004, and 6.5±8.0% vs. 12.8±10.8%, p=0.011, respectively), and the % NC and DC volumes were significantly smaller in VA patients compared with UA patients (12.2±10.3% vs. 17.7±8.1%, p=0.025, and 6.4±6.0% vs. 11.8±8.5%, p=0.007, respectively). The TCFA within lesion segments was less frequently observed in VA patients compared with UA patients (13% vs. 53%, p=0.001).

CONCLUSIONS

VA patients have less plaque, more negative remodeling behavior, more hypoechoic plaque with less calcification, and less NC- and DC-containing lesions and less TCFA lesions compared with UA patients.

Intermediate fixed coronary artery stenosis at the site of ergonovine-provoked spasm as a predictor of long-term major adverse cardiac events of patients with coronary spastic angina

BACKGROUND

Organic coronary artery stenosis is a significant prognostic factor in patients with coronary spastic angina (CSA), so the present study was focused on assessing the impact of intermediate fixed stenosis at sites of provoked spasm on the long-term outcomes of CSA patients.

METHODS AND RESULTS

CSA patients diagnosed on the basis of ergonovine-provoked spasm were enrolled and the clinical background and long-term prognosis of CSA patients with intermediate fixed stenosis at the site of provoked spasm (with-fixed-stenosis group, n=37) and those without fixed stenosis (without-fixed-stenosis group, n=126) were retrospectively compared. During the follow-up period (average 4.01 years for with-fixed-stenosis, 4.47 years for without-fixed-stenosis), the with-fixed-stenosis group had a significantly lower event-free survival rate, as well as a higher frequency of admission for unstable angina and percutaneous coronary intervention than the without-fixed-stenosis group, whereas the survival rate did not differ significantly between the 2 groups. In the multivariate analysis, intermediate fixed stenosis at the site of provoked spasm was a predictor of long-term major adverse cardiac events (MACE).

CONCLUSIONS

Intermediate fixed stenosis at the site of ergonovine-provoked spasm is an independent risk factor for MACE during the long-term period in CSA patients.

Generalized spasm of the right coronary artery after successful stent implantation provoked by intracoronary administration of ergonovine

Coronary spasm may be one of the reasons for the appearance of chest pain after successful percutaneous coronary interventions, and is potentially hazardous when myocardial ischemia occurs. Coronary spasm can be diagnosed by intracoronary administration of ergonovine as a selective spasm provocative test. We report here the case of a patient who had chest pain and ST segment elevation 10 days after successful right coronary artery stent implantation. Repeat angiography was performed, with results of no in-stent stenosis and no stenosis in other segments. Since coronary artery spasm was considered as a possible reason, a spasm provocative test was attempted. Following ergonovine administration (total dose, 50 mug) into the right coronary artery, severe spasm with 99% stenosis developed over the whole artery except the stented segment. Isosorbide dinitrate was injected immediately, and the provoked spasm was soon relieved. Intravascular ultrasound revealed no neointima at the stented segment and diffuse and mild low-echogenic concentric plaque at the distal as well as proximal segment of the stent. Most reports regarding coronary artery spasm provocative tests have focused on focal lesions before interventional therapy, or during interventional procedures. Although it is quite rare, potential coronary spasm should be considered when chest symptoms recur after percutaneous coronary interventions without angiographic representation.

Clinical characteristics of patients with exercise-induced ST-segment elevation without prior myocardial infarction

BACKGROUND

Exercise-induced ST-segment elevation is a relatively uncommon problem and occurs more frequently in patients who have had a myocardial infarction. Data is limited on the characteristics of Taiwanese patients without prior myocardial infarction who develop exercise-induced ST-segment elevation.

METHODS AND RESULTS

Exercise-induced ST-segment elevation developed in 9 of 6,147 consecutive patients without myocardial infarction who underwent treadmill exercise testing at out institution over a 4-year period. The clinical and angiographic characteristics of these patients were studied. Angiographically normal coronary arteries with coronary vasospasm were found in 5 patients, hemodynamically significant coronary stenosis was found in 3 patients, and coexisting spasm in angiographically normal coronary arteries combined with hemodynamically significant coronary stenosis in the different vessel was found in 1 patient. During a median follow-up of 71 months, 2 patients with coronary vasospasm developed recurrent angina after self-discontinuation of calcium antagonists and 2 patients (1 with coronary vasospasm and 1 with hemodynamically significant coronary stenosis) died of cardiac causes before arrival at the emergency department.

CONCLUSION

Coronary vasospasm was a more common underlying pathology of exercise-induced ST-segment elevation in this Taiwanese cohort. Coronary angiography +/- intracoronary ergonovine provocation testing is necessary in these patients to identify the underlying pathology and appropriate treatment.

Motion artifact reduction for IVUS-based thermal strain imaging

Thermal strain imaging (TSI) using intravascular ultrasound (IVUS) has the potential to identify lipid pools within rupture-prone arterial plaques and serve as a valuable supplement to current IVUS systems in diagnosing acute coronary syndromes. The major challenge for in vivo application of TSI will be cardiac motion, including bulk motion and tissue deformation. Simulations based on an artery model, including a lipid-filled plaque, demonstrate that effective bulk motion compensation can be achieved within a certain motion range using spatial interpolation. We also propose a practical imaging scheme to minimize mechanical strains caused by tissue deformation based on a linear least squares fitting strategy. This scheme was tested on clinical data by artificially superimposing thermal displacements corresponding to different temperature rises. Results suggest a 1-2 degrees C temperature rise is required to detect lipids in an atherosclerotic plaque in vivo.

Assessment of Coronary Intima - Media Thickness by Optical Coherence Tomography Comparison With Intravascular Ultrasound

BACKGROUND

Optical coherence tomography (OCT) is a new imaging method. With a resolution of approximately 10-20 Em, which is approximately 10-fold higher than that of intravascular ultrasound (IVUS).

METHODS AND RESULTS

This study compared the coronary intima - media thickness (IMT) and the intimal thickness of 54 coronary arterial segments evaluated by histological examination with the results of OCT and IVUS. There was better agreement in IMT between OCT and histological examination than between IVUS and histological examination (r = 0.95, p < 0.001, mean difference = -0.01+/-0.07 mm for OCT; r = 0.88, p < 0.001, mean difference = -0.03+/-0.10 mm for IVUS). There was good agreement in the intimal thickness between OCT and histological examination (r = 0.98, p < 0.001, mean difference = 0.01+/-0.04 mm).

CONCLUSIONS

IMT could be measured more accurately by OCT than IVUS. In addition, the intimal thickness could be evaluated by OCT and correlated well with the histological examination.

Lesion Severity and Hypercholesterolemia Determine Long-Term Prognosis of Vasospastic Angina Treated With Calcium Channel Antagonists

Although patients with medically treated vasospastic angina have a good outcome, few data exist regarding the role of underlying lesion severity associated with or without hyperlipidemia in the prognosis. Therefore, the aim of the present study was to assess the relationship between the long-term outcome of vasospastic angina and the factors influencing its prognosis. A total of 256 patients (219 men, 37 women; mean age, 54.1+/-9.2) who had coronary spasm with or without underlying lesions and were being treated with calcium channel antagonists were enrolled and followed for 13.6+/-3.7 years. Cardiac events consisted of cardiac death and ischemic events, which included acute myocardial infarction and unstable angina. Cox analysis selected coronary artery stenosis (CAS, >/=50%) and risk factors such as age, hypertension, diabetes mellitus, low-density lipoprotein-cholesterol (LDL-C), sex and smoking. There were 19 cases of cardiac death (7.4%) and 58 of ischemic events (22.7%) during the follow-up period. The presence of significant CAS was an independent predictor of event-free survival (hazard ratio (HR) =2.84, 95% confidence interval (CI) =1.79-4.52, p<0.0001). In 193 patients without significant CAS, there were 10 cases of cardiac death (5.2%, p<0.05) and 34 of ischemic events (17.6%, p<0.01). In that group, high LDL-C was the independent predictor of event-free survival (HR = 3.89, 95% CI = 1.20-12.6, p=0.02). Kaplan-Meier survival analysis revealed significantly lower event-free survival in patients with than in those without lesions (p<0.0001 by log-rank test). These results demonstrate that the most important factor for long-term prognosis of vasospastic angina treated with calcium channel antagonists is significant CAS. High LDL-C, which might alter the underlying coronary endothelial function and/or accelerate atherosclerotic lesions, could also contribute to the occurrence of cardiac events, particularly in patients without significant CAS.