Coronary vasospasm as a possible cause of elevated cardiac troponin I in patients with acute coronary syndrome and insignificant coronary artery disease

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.

Insights into the invasive diagnostic challenges of coronary artery vasospasm - A systematic review

Coronary provocation testing is an essential diagnostic procedure when evaluating vasospastic angina. Invasive methods using acetylcholine or ergonovine are considered the current gold standard. Despite efforts from global cardiovascular institutions, current protocols vary in dosage, administration time, and procedural approach. In addition, concerns over the specificity of findings and potential complications have limited routine uptake of this procedure in clinical practice. This systematic review evaluates current diagnostic protocols, focusing on invasive provocation testing. We included studies using intracoronary provocation testing with acetylcholine or ergonovine for the assessment of coronary artery vasospasm that detailed specific elements of the procedure (dosage, administration time, etc.) and included ≥50 patients. A total of 28 articles met strict inclusion criteria. Our review highlights the heterogeneity between current diagnostic protocols for invasive provocation testing. We believe standardization of a diagnostic protocol will encourage both current and future cardiologists to incorporate such procedures in the evaluation of variant angina.

Angina and Non-Obstructive Coronary Artery (ANOCA) Patients with Coronary Vasomotor Disorders

Angina and Non-Obstructive Coronary Artery (ANOCA) patients often lack a clear explanation for their symptoms, and are frequently discharged with the label of "unspecified chest pain", despite the availability of functional coronary angiography (provocative spasm and microvascular function testing) to identify potential underlying coronary vasomotor disorders. This study compared the outcomes of ANOCA patients with a coronary vasomotor disorder diagnosis post elective coronary angiography to patients discharged with unspecified chest pain. Using the CADOSA (Coronary Angiogram Database of South Australia) registry, consecutive symptomatic patients (n = 7555) from 2012 to 2018 underwent elective angiography; 30% had ANOCA (stenosis <50%). Of this cohort, 9% had documented coronary vasomotor disorders diagnosed, and 91% had unspecified chest pain. Patients with coronary vasomotor disorders were younger and had a similar female prevalence compared with those with unspecified chest pain. New prescriptions of calcium channel blockers and long-acting nitrates were more common for the coronary vasomotor cohort at discharge. In the 3 years following angiography, both groups had similar all-cause mortality rates. However, those with coronary vasomotor disorders had higher rates of emergency department visits for chest pain (39% vs. 15%, p < 0.001) and readmissions for chest pain (30% vs. 10%, p < 0.001) compared with those with unspecified chest pain. This real-world study emphasizes the importance of identifying high-risk ANOCA patients for personalized management to effectively address their symptoms.

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.

Assessment of coronary spasms with transluminal attenuation gradient in coronary computed tomography angiography

Purpose

To evaluate the imaging features of coronary spasm, including transluminal attenuation gradient (TAG) on coronary computed tomography angiography (CCTA), in patients with vasospastic angina (VA).

Methods

A total of 43 patients with a high clinical likelihood of VA were included in the study. All the subjects underwent double CCTA acquisition: CCTA without a vasodilator (‘baseline CT’) and CCTA during continuous intravenous nitrate infusion (‘IV nitrate CT’). A catheterized ergonovine provocation test was used to determine true VA patients. Coronary spasm is classified into focal- and diffuse-types according to morphological differences. We measured TAG and contrast enhancement of the proximal ostium (ProxHU) of each coronary artery for both the baseline and IV nitrate CT.

Results

Twenty-four patients (55.8%) showed positive results of coronary vasospasm on the provocation test. Thirty-eight vessels showed coronary spasms (29.5%): Focal-type in nine vessels (24%), and diffuse-type in 29 (76%). In the baseline CT, LCX showed significantly lower (steeper) TAG in spasm(+) vessels than in spasm(-) vessels, while LAD and RCA showed no significant differences in TAG. The ProxHU of LAD showed significantly lower values in spasm(+) vessels than in spasm(-) vessels, while the other vessels did not show significant differences in ProxHU. For IV nitrate CT, there were no significant differences in either the TAG and ProxHU between spasm(+) and (-) vessels for all the three vessel types. In subgroup analysis for spasm(+) vessels, diffuse spasms showed significantly lower TAG than focal spasms, while the ProxHU did not differ between the two types of spasm.

Conclusions

A relatively large percentage of coronary spasms present as diffuse type, and the TAG values significantly differed according to the morphological type of the coronary spasm.

A Case of Elevated Troponin I Level After Packed Red Blood Cell Transfusion With Normal Coronary Angiography

Other than acute coronary syndrome (ACS), many clinical conditions are associated with increased cardiac troponin I (cTnI) levels. Conditions such as pulmonary embolism, acute heart failure, myocarditis, sepsis, and renal failure are commonly reported as underlying causes. Analytical interference with the cTnI assay can also lead to falsely elevated troponin I levels. That can happen due to multiple causes such as fibrin clots, heterophile antibodies, microparticles contained in the sample, rheumatoid factor, interference by bilirubin, hemolysis, and elevated alkaline phosphatase activity. Herein, we present the case of a 66-year-old female who presented with pleuritic chest pain and had a cTnI of 35.5 ng/mL post-transfusion of three units of packed red blood cells. The patient had a complete ischemic workup for ACS, including coronary angiography, which was negative for coronary artery disease.

A Practical Approach to Invasive Testing in Ischemia with No Obstructive Coronary Arteries (INOCA)

Up to 65% of women and approximately 30% of men have ischemia with no obstructive coronary artery disease (CAD; commonly known as INOCA) on invasive coronary angiography performed for stable angina. INOCA can be due to coronary microvascular dysfunction or coronary vasospasm. Despite the absence of obstructive CAD, those with INOCA have an increased risk of all-cause mortality and adverse outcomes, including recurrent angina and cardiovascular events. These patients often undergo repeat testing, including cardiac catheterization, resulting in lifetime healthcare costs that rival those for obstructive CAD. Patients with INOCA often remain undiagnosed and untreated. This review discusses the symptoms and prognosis of INOCA, offers a systematic approach to the diagnostic evaluation of these patients, and summarizes therapeutic management, including tailored therapy according to underlying pathophysiological mechanisms.

Biomarker Development in Cardiology: Reviewing the Past to Inform the Future

Cardiac biomarkers have become pivotal to the clinical practice of cardiology, but there remains much to discover that could benefit cardiology patients. We review the discovery of key protein biomarkers in the fields of acute coronary syndrome, heart failure, and atherosclerosis, giving an overview of the populations they were studied in and the statistics that were used to validate them. We review statistical approaches that are currently in use to assess new biomarkers and overview a framework for biomarker discovery and evaluation that could be incorporated into clinical trials to evaluate cardiovascular outcomes in the future.

The Pivotal Role of Invasive Functional Assessment in Patients With Myocardial Infarction With Non-Obstructive Coronary Arteries (MINOCA)

Myocardial infarction with non-obstructive coronary arteries (MINOCA) encompasses several pathophysiological mechanisms not yet fully understood. Among the latter, vasomotion abnormalities and coronary microvascular dysfunction (CMD) play a major role for both epidemiological and prognostic reasons. Despite current guidelines do not recommend routine physiological assessment of both epicardial and microvascular coronary compartments within the context of an acute myocardial infarction, several recent evidence support the critical role of a comprehensive invasive functional assessment in order to identify the underlying pathophysiological mechanism and consequently to select an appropriate therapeutic strategy. Unfortunately, optimal medical therapy for these patients is not currently established due to the lack of dedicated trials evaluating clinical outcomes of commonly used medications for secondary prevention in MINOCA patients. For this reason, additional research is warranted to provide personalized treatments for patients affected by this puzzling clinical entity.

[Methergin pour le diagnostic de l'angor spastique : voie intraveineuse ou intracoronaire ?]

BACKGROUND

Vasospastic angina is an infrequent underlying cause of angina and is under-diagnosed. Ergonovine provocation tests can be performed via intravenous or intracoronary injections. Although the safety profile of intracoronary injection has been well documented, no study has yet compared the intracoronary and intravenous injections regarding the positivity rate of the test.

AIMS

This study sought to compare the positivity rate of intravenous versus intracoronary injection of ergonovine in the diagnosis of vasospastic angina.

METHODS

Between January 2010 and February 2018, 427 patients with suspected vasospastic angina underwent an ergonovine provocation test in 2 tertiary hospitals in France and were retrospectively included in this study. Injection was performed via the intravenous or the intracoronary route. The primary endpoint was the positivity rate of the test. Propensity score matching was used to account for confounding factors.

RESULTS

427 patients were included in the study. Mean age was 60.3 (+/- 12.4) years. There were 247 (58%) females and 97 (23%) smokers. The intracoronary route was used in 199 (47%) patients. The indication for the test was acute coronary syndrome for 121 (28%). No rhythmic complications or deaths were reported. After propensity-matching, the baseline characteristics of the 2 groups (148 patients in each) were comparable. The positivity rate was 24% in the intracoronary group and 9% in the intravenous group (OR [95%CI]: 3.2 [1.6, 6.4]).

CONCLUSIONS

Intracoronary injection of ergonovine is safe and associated with a positivity rate of the test three times higher compared to intravenous injection.

Coronary artery spasm-induced acute myocardial infarction in patients with myocardial infarction with non-obstructive coronary arteries

Coronary artery spasm-induced acute myocardial infarction (CASIAMI) is one of the etiologies of myocardial infarction with non-obstructive coronary arteries (MINOCA). We retrospectively analyzed the incidence and clinical characteristics of Japanese patients with CASIAMI and non-obstructive coronary arteries. We experienced 62 patients with MINOCA (10 thrombosis, 7 unknown causes, and 45 CASIAMI) among 991 patients with suspected AMI. Pharmacological spasm provocation testing was performed in 37 patients. CASIAMI without obstructive coronary arteries was found in 4.5% of patients with suspected AMI and was observed in 73% of patients with MINOCA. Patients with CASIAMI were frequently males and had relatively small AMIs. Spontaneous spasm was recognized in 8 patients. We could reproduce provoked spasm in 37 patients with MINOCA, including 23 patients with multiple spasm. No patients died during the follow-up period. The clinical outcomes in patients with CASIAMI under optimal coronary vasodilators were satisfactory.

Myocardial infarct size and sex-related angiographic differences in myocardial infarction in nonobstructive coronary artery disease

BACKGROUND

Myocardial infarction in nonobstructive coronary artery disease (MINOCA) is a recently described infarct subtype. There are few studies that examine coronary artery disease (CAD) extent, MI size and type, and treatment differences at hospital discharge compared to myocardial infarction in obstructive coronary artery disease (MICAD), or that explore sex-specific MINOCA attributes of coronary anatomy and infarct size.

METHODS

Our study population consisted of a single tertiary-center of consecutive patients that had coronary angiography for acute MI between 2005 and 2015. The MI type at presentation, MI size and ejection fraction (post-MI), and gender differences between MINOCA patients were examined.

RESULT

Among 1698 cases with acute MI, 95 had MINOCA (5.6%). MINOCA patients were younger, more often had NSTEMI, lower peak cardiac troponin (cTn) values, and greater ejection fraction than MICAD patients (all P-values <0.005). At hospital discharge, 30-day re-admission rates were similar. MINOCA patients less frequently received optimal medical therapy. When women were analyzed, the 45 women with MINOCA had smaller MIs (P < 0.001) and greater ejection fraction (P = 0.002) than the 358 women with MICAD. Sex comparisons of the 95 MINOCA patients revealed women were older than men (P < 0.001), had lower mean peak cTn values (P < 0.001), greater ejection fraction (P = 0.02), and more single-vessel disease involvement than men (P < 0.0001).

CONCLUSION

The average MI size is smaller in MINOCA than MICAD patients, and there are sex-related differences in clinical presentation, coronary artery disease extent, and MI size. Re-admission rates are similar and MINOCA patients are less likely to receive guideline recommended medical therapy at discharge.

Comparison of calcium-channel blockers for long-term clinical outcomes in patients with vasospastic angina

BACKGROUND/AIMS

Calcium channel blockers (CCBs) are the most widely prescribed medication for patients with vasospastic angina (VA). However, few studies have compared the prognosis of VA patients who are prescribed different CCBs.

METHODS

We enrolled 2,960 patients who received provocation test prospectively in 11 university hospitals in Korea. We divided 1,586 patients received four major CCBs into two groups: a first generation CCB (diltiazem and nifedipine) group and a second generation CCB (amlodipine and benidipine) group. Primary outcome was time to events of composite of death from any cause, acute coronary syndrome (ACS) and symptomatic arrhythmia during 3-year follow-up. We also compared the effect of each CCB on the control of angina symptoms.

RESULTS

There was no difference of the primary outcome among the two groups with a cumulative incidence rate of 5.4%, 2.9%, and a person-month incidence rate of 2.33 and 1.26, respectively (hazard ratio [HR], 0.54; 95% confidence interval [CI], 0.25 to 1.17; p = 0.120, as reference with the 1st generation CCBs). The incidence of ACS was significantly lower in 2nd generation CCBs group with a person-month incidence rate of 1.66 vs. 0.35 (HR, 0.22; 95% CI, 0.05 to 0.89; p = 0.034). Use of benidipine showed a significant better control of angina symptom compared with diltiazem for 3 years (odds ratio, 0.17; 95% CI, 0.09 to 0.32; p < 0.0001 at 3rd year).

CONCLUSION

The first and second generation CCB groups did not differ in terms of composite outcome occurrence. However, the ACS incidence rate was significantly lower in the users of the 2nd generation CCBs.

Diffuse coronary artery vasospasm in a patient with subarachnoid hemorrhage: A case report

BACKGROUND

Coronary artery vasospasm (CAV) is a reversible, transient form of vasoconstriction with clinical manifestations ranging from stable angina to acute coronary syndromes (ACS). Vasospasm of epicardial coronary arteries or associated micro-vasculature can lead to total or subtotal occlusion and has been demonstrated in nearly 50% of patients undergoing angiography for suspected ACS. The mechanism for CAV has been described in literature, but in a subgroup of patients presenting with intracranial hemorrhage, it appears to be multifactorial. These patients tend to have electrocardiographic changes, elevation of cardiac biomarkers of injury and neurogenic stress cardiomyopathy.

CASE SUMMARY

A 44-year-old woman presented with severe headaches and tonic-clonic seizures. She was found to have diffuse subarachnoid hemorrhage (SAH) requiring ventricular drain placement, coil embolization and induced hypertension. She subsequently developed chest pain with ST elevations in anterior precordial leads, elevated cardiac enzymes and apical ballooning with left ventricular ejection fraction of 35% on transthoracic echocardiogram. Coronary angiogram revealed severe diffuse triple vessel stenoses secondary to CAV seen distally. Subsequent cardiac MRI notable for apical non-viability and scar formation.

CONCLUSION

This case highlights a unique etiology of acute myocardial infarction in a patient with SAH leading to ST elevations, diffuse triple vessel CAV and apical scar.

Associations of myocardial bridging with adverse cardiac events: a meta-analysis of published observational cohort studies involving 4,556 individuals

Background

Data derived from small series have demonstrated an association of myocardial bridge (MB) with adverse cardiac events, while MB has been traditionally considered as a benign condition. Hence, the precise clinical implications of MB on prognosis remains inconsistent. Our purpose is to perform a meta-analysis to assess the clinical implications of MB on prognosis.

Methods

We performed an extensive search of PubMed and reference lists of relevant articles. Studies which compared prognosis between subjects with and without MB were identified from 1960 to 31 March 2018. Studies selection was limited to human data and restricted to English language.

Results

Six eligible studies were included in current meta-analysis. Of 4,556 subjects, 1,389 (30.5%) presented MB. MB was associated with an increased risk of adverse cardiac events [odds ratio (OR), 1.71; 95% confidence interval (CI): 1.29 to 2.26; P=0.0002], non-fatal myocardial infarction (OR: 3.17; 95% CI: 1.21 to 8.31; P=0.02), and angina requiring hospitalization (OR: 2.31; 95% CI: 1.55 to 3.45; P<0.0001), respectively, compared with subjects without MB.

Conclusions

This meta-analysis of currently available observational cohort studies suggests that MB has an association with adverse cardiac events. Further prospective multicenter studies with large sample size are needed to confirm current findings. Moreover, studies refining the impact of different types of MB on cardiac events, myocardial ischemia, and symptoms requiring therapy, may provide more insights to this issue.

Patients with acute myocardial infarction and non-obstructive coronary arteries: safety and prognostic relevance of invasive coronary provocative tests

Aims

Functional alterations of epicardial coronary arteries or coronary microcirculation represent a frequent cause of myocardial infarction and non-obstructive coronary arteries (MINOCA). We aimed at assessing the prognostic value of intracoronary provocative tests in patients presenting with MINOCA and in which other causes of MINOCA have been excluded.

Methods and results

We prospectively evaluated patients with a diagnosis of MINOCA, excluding patients with aetiologies other than suspected coronary vasomotor abnormalities. Immediately after coronary angiography, an invasive provocative test using acetylcholine or ergonovine was performed. The incidence of death from any cause, cardiac death, and recurrence of acute coronary syndrome (ACS) was assessed at follow-up. We also assessed angina status using Seattle Angina Questionnaires (SAQ). We enrolled 80 consecutive patients [mean age 63.0 ± 10.7 years, 40 (50%) male]. Provocative test was positive in 37 (46.2%) patients without any complication. Among patients with a positive test, epicardial spasm was detected in 24 (64.9%) patients and microvascular spasm in 13 (35.1%) patients. After a median follow-up of 36.0 (range 12.0-60.0) months, patients with a positive test had a significantly higher occurrence of death from any cause [12 (32.4%) vs. 2 (4.7%); P = 0.002], cardiac death [7 (18.9%) vs. 0 (0.0%); P = 0.005], and readmission for ACS [10 (27.0%) vs. 3 (7.0%); P = 0.015] as well as a worse angina status as assessed by SAQ [Seattle score: 88.0 (33.0-100.0) vs. 100.0 (44.0-100.0); P = 0.001] when compared with patients with a negative test.

Conclusions

We demonstrate that in patients presenting with MINOCA and suspected coronary vasomotor abnormalities, a positive provocative test for spasm is safe and identifies a high-risk subset of patients.

Safety and usefulness of acetylcholine provocation test in patients with no culprit lesions on emergency coronary angiography

BACKGROUND

Vasospastic angina (VSA), which often causes acute coronary syndrome (ACS), can be diagnosed by intracoronary acetylcholine (ACh) provocation test. However, the safety and usefulness of ACh provocation test in ACS patients on emergency coronary angiography (CAG) compared to non-emergency settings are unclear.

METHODS

A total of 529 patients undergoing ACh provocation test during emergency or non-emergency CAG were included. Patients with resuscitated cardiac arrest were excluded. The primary endpoint was adverse events defined as a composite of death, ventricular fibrillation or sustained ventricular tachycardia, myocardial infarction, cardiogenic shock, cardiac tamponade, and stroke within 24 h after ACh provocation test.

RESULTS

There were no significant differences of the clinical characteristics between the groups of emergency (n = 84) and non-emergency (n = 445) ACh provocation test. The rate of positive ACh provocation test was similar between the 2 groups (50% vs. 49%, p = 0.81). Similarly, the incidence of adverse events in patients with emergency and non-emergency ACh provocation test did not significantly differ (1.2% vs. 1.3%, p = 1.00).

CONCLUSION

ACh provocation test can be safely performed in ACS patients with no obstructive culprit lesions on emergency CAG, and may be useful to diagnose VSA in those patients.

Clinical characteristics of patients with suspected cardiac chest pain and angiographically normal coronary arteries in a secondary care hospital

BACKGROUND

An important number of patients with suspected cardiac chest pain have non-obstructive coronary artery disease. Our purpose was to describe the clinical characteristics of patients with normal or near-normal coronary arteries in routine cardiological practice in a secondary care hospital.

METHODS

In 2013, consecutive patients referred for invasive coronary angiography with suspected cardiac chest pain were analysed at a single-centre (Westfriesgasthuis, Hoorn, the Netherlands). Coronary arteries were defined as normal or near-normal if they showed no stenosis or only slight wall irregularities on visual assessment. Patients with a final non-cardiac diagnosis for the chest pain were excluded.

RESULTS

A total of 558 patients were included. Of these, 151 (27%) showed normal or near-normal coronary arteries on visual assessment. This group of patients were significantly more often female (p < 0.001), younger (p < 0.001) and non-diabetic (p = 0.002). Forty percent of hospitalised patients who had normal or near-normal coronary arteries at coronary angiography showed an elevated troponin.

CONCLUSION

In routine cardiological practice, around 1 out of 4 patients with suspected cardiac chest pain undergoing invasive angiography had normal or near-normal coronary arteries. We suggest that premenopausal women with suspected cardiac chest pain could be considered for non-invasive coronary imaging as a first step in clinical practice.

High susceptibility of atherosclerotic coronary arteries to the onset of vasospasm and angina pectoris-like symptoms due to coronary spasm in WHHLMI rabbits

We examined the relationship between atherosclerosis and the provocation of coronary spasm as well as the influence of coronary spasm on the onset of acute ischemic myocardial disease. Coronary spasm was provoked in anesthetized normal Japanese white (JW) rabbits and myocardial infarction-prone Watanabe heritable hyperlipidemic (WHHLMI) rabbits, an animal model for coronary atherosclerosis and myocardial infarction, by injecting ergonovine during the infusion of norepinephrine through a marginal ear vein. A decrease in contrast flow in the left circumflex artery was observed on coronary angiograms. Ischemic changes were observed on the electrocardiograms of 29% (2/7) of JW and 79% (27/34, P=0.007) of WHHLMI rabbits. The frequency of coronary spasm was significantly high in rabbits with severe coronary plaques showing diffuse lesions. Left ventricle motility in vasospasm-positive rabbits, which was evaluated with echocardiograms, was decreased by 29% following the ergonovine injection (P<0.001), and every serum ischemic marker markedly increased 4 h after the provocation of vasospasm. These results demonstrate that atherosclerotic coronary arteries are positively related to the provocation of vasospasm, and vasospasm in severe atherosclerotic coronary segments evokes angina pectoris-like findings and/or non-fatal myocardial infarction. WHHLMI rabbits may be a novel animal model for angina pectoris and acute ischemic heart disease.

Recurrent Myocardial Infarction in a Patient with an Arteriovenous Coronary Fistula and No Coronary Artery Disease

Myocardial infarction in the absence of coronary artery disease is a rare finding. Mechanisms leading to infarction include paradoxical embolism, coronary dissection, coronary spasm, hypercoagulable states, vasculitis, or-in presence of a coronary fistula-a steal phenomenon. We report for the first time a case of a patient with an arteriovenous coronary fistula and no coronary artery disease, suffering from three incidents of myocardial infarction in three different coronary regions-of which only one was located in the area supplied by the coronary artery connected to the fistula.

A model for predicting angiographically normal coronary arteries in survivors of out-of-hospital cardiac arrest

BACKGROUND

It has been recommended that all survivors of out-of-hospital cardiac arrest (OHCA) have immediate coronary angiography (CAG), even though it has been reported that half of the survivors have normal coronary arteries. Our aim was to develop a model which might identify those who have angiographically normal coronary arteries. Reliable prediction would reduce unnecessary CAG.

METHODS

A retrospective, observational, cohort study was conducted on 47 consecutive adult survivors who received immediate CAG after resuscitation from OHCA, between June 1, 2006 and March 31, 2011. We analyzed the clinical and electrocardiographic characteristics of the survivors with and without normal coronary arteries.

RESULTS

All subjects had CAG. Normal coronary arteries were found in 25/47. These persons did not have diabetes mellitus (p = 0.0069) or a history of acute coronary syndrome (ACS) (p = 0.0069). Any abnormality of the ST segment or ST segment elevation on electrocardiogram (ECG) was strongly related to abnormal coronary arteries (p = 0.0045 and p = 0.0200, respectively). The partitioning model for predicting angiographically normal coronary arteries showed that all patients (8/8) with no ST segment change on their ECG had normal coronary arteries. Eight out of ten patients with ST segment abnormalities also had normal coronary arteries with a history of arrhythmia without a history of ACS.

CONCLUSIONS

Survivors of OHCA who have no history of diabetes mellitus, who have no past history of ACS, and who present with no ST segment abnormalities may not require urgent/emergent CAG. Further studies are needed to guide clinicians in the determination of emergent cardiac catheterization following resuscitation of OHCA.

Recurrent myocardial infarction secondary to Prinzmetal's variant angina

Prinzmetal's variant angina describes chest pain secondary to reversible coronary artery vasospasm in the context of both diseased and non-diseased coronary arteries. Symptoms typically occur when the patient is at rest and are associated with transient ST-segment elevation. Acute episodes respond to glyceryl trinitrate, but myocardial infarction and other potentially fatal complications can occur, and long-term management can be challenging. Although it is not well understood, the underlying mechanism appears to involve a combination of endothelial damage and vasoactive mediators. In this case, a 35-year-old woman with myocardial infarction secondary to coronary artery vasospasm experienced recurrent chest pain. Coronary angiography revealed severe focal stenosis in the mid left anterior descending artery, which completely resolved after administration of intracoronary glyceryl trinitrate. The patient was discharged on nitrates and calcium channel blockers. The patient re-presented with another myocardial infarction, requiring up-titration of medical therapy.

Clinical features and prognosis of type 2 myocardial infarction in vasospastic angina

BACKGROUND

Although generally the prognosis of vasospastic angina is considered excellent, vasospasm has been shown to be a cause of type 2 myocardial infarction. This study was performed to investigate the clinical characteristics and prognosis of patients with vasospastic angina complicated with type 2 myocardial infarction.

METHODS

We performed a retrospective analysis of 171 consecutive patients with definite vasospastic angina (median age, 64 years; 55.0% were male) who visited the Kameda Medical Center with chest pain and in whom cardiac troponin I level was measured between 2005 and 2013. The patients were divided into type 2 myocardial infarction and non-type 2 myocardial infarction groups. A diagnosis of type 2 myocardial infarction was based on a serum cardiac troponin I value >99th percentile upper reference limit. The primary end point was a combination of nonfatal myocardial infarction or death by any cause.

RESULTS

A total of 42 patients (24.6%) were diagnosed with type 2 myocardial infarction, and the type 2 myocardial infarction group had a higher incidence of combined end point than the non-type 2 myocardial infarction group during the median follow-up of 4.4 years (26.2% vs 9.3%, respectively, P = .008). Type 2 myocardial infarction remained an independent predictor of combined end point even after adjusting by the Japanese Coronary Spasm Association risk factors for combined end point (hazard ratio, 2.84; 95% confidence interval, 1.22-6.61; P = .02).

CONCLUSIONS

Approximately one quarter of patients with vasospastic angina were associated with type 2 myocardial infarction, and this population should be identified as a new high-risk subgroup of those with vasospastic angina requiring an alternative treatment strategy.

Systematic review of patients presenting with suspected myocardial infarction and nonobstructive coronary arteries

BACKGROUND

Myocardial infarction with nonobstructive coronary arteries (MINOCA) is a puzzling clinical entity with no previous evaluation of the literature. This systematic review aims to (1) quantify the prevalence, risk factors, and 12-month prognosis in patients with MINOCA, and (2) evaluate potential pathophysiological mechanisms underlying this disorder.

METHODS AND RESULTS

Quantitative assessment of 28 publications using a meta-analytic approach evaluated the prevalence, clinical features, and prognosis of MINOCA. The prevalence of MINOCA was 6% [95% confidence interval, 5%-7%] with a median patient age of 55 years (95% confidence interval, 51-59 years) and 40% women. However, in comparison with those with myocardial infarction associated with obstructive coronary artery disease, the patients with MINOCA were more likely to be younger and female but less likely to have hyperlipidemia, although other cardiovascular risk factors were similar. All-cause mortality at 12 months was lower in MINOCA (4.7%; 95% confidence interval, 2.6%-6.9%) compared with myocardial infarction associated with obstructive coronary artery disease (6.7%, 95% confidence interval, 4.3%-9.0%). Qualitative assessment of 46 publications evaluating the underlying pathophysiology responsible for MINOCA revealed the presence of a typical myocardial infarct on cardiac magnetic resonance imaging in only 24% of patients, with myocarditis occurring in 33% and no significant abnormality in 26%. Coronary artery spasm was inducible in 27% of MINOCA patients, and thrombophilia disorders were detected in 14%.

CONCLUSIONS

MINOCA should be considered as a working diagnosis with multiple potential causes that require evaluation so that directed therapies may improve its guarded prognosis.

Nonobstructive coronary artery disease and risk of myocardial infarction

IMPORTANCE

Little is known about cardiac adverse events among patients with nonobstructive coronary artery disease (CAD).

OBJECTIVE

To compare myocardial infarction (MI) and mortality rates between patients with nonobstructive CAD, obstructive CAD, and no apparent CAD in a national cohort.

DESIGN, SETTING, AND PARTICIPANTS

Retrospective cohort study of all US veterans undergoing elective coronary angiography for CAD between October 2007 and September 2012 in the Veterans Affairs health care system. Patients with prior CAD events were excluded.

EXPOSURES

Angiographic CAD extent, defined by degree (no apparent CAD: no stenosis >20%; nonobstructive CAD: ≥1 stenosis ≥20% but no stenosis ≥70%; obstructive CAD: any stenosis ≥70% or left main [LM] stenosis ≥50%) and distribution (1, 2, or 3 vessel).

MAIN OUTCOMES AND MEASURES

The primary outcome was 1-year hospitalization for nonfatal MI after the index angiography. Secondary outcomes included 1-year all-cause mortality and combined 1-year MI and mortality.

RESULTS

Among 37,674 patients, 8384 patients (22.3%) had nonobstructive CAD and 20,899 patients (55.4%) had obstructive CAD. Within 1 year, 845 patients died and 385 were rehospitalized for MI. Among patients with no apparent CAD, the 1-year MI rate was 0.11% (n = 8, 95% CI, 0.10%-0.20%) and increased progressively by 1-vessel nonobstructive CAD, 0.24% (n = 10, 95% CI, 0.10%-0.40%); 2-vessel nonobstructive CAD, 0.56% (n = 13, 95% CI, 0.30%-1.00%); 3-vessel nonobstructive CAD, 0.59% (n = 6, 95% CI, 0.30%-1.30%); 1-vessel obstructive CAD, 1.18% (n = 101, 95% CI, 1.00%-1.40%); 2-vessel obstructive CAD, 2.18% (n = 110, 95% CI, 1.80%-2.60%); and 3-vessel or LM obstructive CAD, 2.47% (n = 137, 95% CI, 2.10%-2.90%). After adjustment, 1-year MI rates increased with increasing CAD extent. Relative to patients with no apparent CAD, patients with 1-vessel nonobstructive CAD had a hazard ratio (HR) for 1-year MI of 2.0 (95% CI, 0.8-5.1); 2-vessel nonobstructive HR, 4.6 (95% CI, 2.0-10.5); 3-vessel nonobstructive HR, 4.5 (95% CI, 1.6-12.5); 1-vessel obstructive HR, 9.0 (95% CI, 4.2-19.0); 2-vessel obstructive HR, 16.5 (95% CI, 8.1-33.7); and 3-vessel or LM obstructive HR, 19.5 (95% CI, 9.9-38.2). One-year mortality rates were associated with increasing CAD extent, ranging from 1.38% among patients without apparent CAD to 4.30% with 3-vessel or LM obstructive CAD. After risk adjustment, there was no significant association between 1- or 2-vessel nonobstructive CAD and mortality, but there were significant associations with mortality for 3-vessel nonobstructive CAD (HR, 1.6; 95% CI, 1.1-2.5), 1-vessel obstructive CAD (HR, 1.9; 95% CI, 1.4-2.6), 2-vessel obstructive CAD (HR, 2.8; 95% CI, 2.1-3.7), and 3-vessel or LM obstructive CAD (HR, 3.4; 95% CI, 2.6-4.4). Similar associations were noted with the combined outcome.

CONCLUSIONS AND RELEVANCE

In this cohort of patients undergoing elective coronary angiography, nonobstructive CAD, compared with no apparent CAD, was associated with a significantly greater 1-year risk of MI and all-cause mortality. These findings suggest clinical importance of nonobstructive CAD and warrant further investigation of interventions to improve outcomes among these patients.

Provocative testing for coronary reactivity and spasm

Coronary spasm is an important and often overlooked etiology of chest pain. Although coronary spasm, or Prinzmetal's angina, has been thought of as benign, contemporary studies have shown serious associated adverse outcomes, including acute coronary syndrome, arrhythmia, and death. Definitive diagnosis of coronary spasm can at times be difficult, given the transience of symptoms. Numerous agents have been historically described for provocative testing. We provide a review of published data for the role of provocation testing in the diagnosis of coronary spasm.

Troponin elevation in supraventricular tachycardia: primary dependence on heart rate

BACKGROUND

It is known that some patients with supraventricular tachycardia (SVT) could have increased troponin levels without coronary artery disease.

OBJECTIVES

To compare the cardiovascular risk of patients admitted with SVT with troponin T elevation (T+ patients) versus those without (T- patients), to determine if the rise in troponin levels could be predicted, and to identify the right approach in T+ patients.

METHODS

Retrospective database search of patients with SVT from 2002 to 2007 either with or without troponin T elevation at admission.

RESULTS

Of the 73 study patients, there were 24 (32.9%) T+ patients and 49 (67.1%) T- patients. All except 5 T+ patients underwent either a stress test/MIBI or a coronary angiogram. Two noninvasive tests were positive and only 1 patient needed an angiogram and percutaneous coronary intervention; none of the other angiograms triggered any further treatment. Of the 49 T- patients, 11 had a noninvasive stress test; none of these tests was positive or triggered any further treatment. Compared with that of T- patients, the maximum heart rate was significantly higher in T+ patients (190.8 versus 170.3 beats per minute, P = .008). A correlation was found between the maximal heart rate during SVT and the level of troponin elevation (r = 0.637, P = .001).

CONCLUSIONS

SVT could be associated with a troponin elevation without any severe coronary artery disease. In most patients, either conservative management or noninvasive stratification seems to be sufficient; an invasive strategy could then be reserved only for high-risk patients who tested positive. The only clinical variable correlated with the troponin rise was a higher maximal heart rate during the SVT episode.

Surgical reconstruction of the left main coronary artery with patch-angioplasty

Background

Conventional coronary artery bypass grafting (CABG) has been established as the treatment of choice for left main coronary artery (LMCA) stenosis However, the conventional grafting provides a retrograde perfusion to extensive myocardial area and leads prospectively to competitive flow of the non-occluded coronaries thus consuming the grafts. Surgical reconstruction of the LMCA with patch-angioplasty is an alternative method that eliminates these drawbacks.

Methods

Between February 1997 and July 2007, 37 patients with isolated LMCA stenosis were referred for surgical ostial reconstruction. In 27 patients (73%) surgical angioplasties have been performed. All patients were followed up clinically and with transesophageal echocardiography (TEE) and coronary angiography when required.

Results

In 10 patients (27%) a LMCA stenosis could not be confirmed. There were no early mortality or perioperative myocardial infarctions. The postoperative course was uneventful in all patients. In 25 patients, TEE demonstrated a wide open main stem flow pattern one to six months after reconstruction of the left main coronary artery with one patch mild aneurysmal dilated.

Conclusions

The surgical reconstruction with patch-angioplasty is a safe and effective method for the treatment of proximal and middle LMCA stenosis. Almost one third of the study group had no really LMCA stenosis: antegrade flow pattern remained sustained and the arterial grafts have been spared. In the cases of unclear or suspected LMCA stenosis, cardio-CT can be performed to unmask catheter-induced coronary spasm as the underlying reason for isolated LMCA stenosis.

3-year follow-up of patients with coronary artery spasm as cause of acute coronary syndrome: the CASPAR (coronary artery spasm in patients with acute coronary syndrome) study follow-up

OBJECTIVES

We sought to determine the prognosis of patients with acute coronary syndrome without culprit lesion and proof of coronary spasm during 3 years of follow-up.

BACKGROUND

Coronary artery spasm has been identified as an alternative cause for acute coronary syndrome (ACS) in patients without culprit lesion. In the CASPAR (Coronary Artery Spasm as a Frequent Cause for Acute Coronary Syndrome) study, we recently showed that ∼50% of ACS patients without culprit lesion, in whom intracoronary acetylcholine provocation was performed, had coronary spasm. However, data on prognosis in these patients are sparse.

METHODS

After 3 years of follow-up, data regarding the following end points were obtained: death (cardiac and noncardiac), nonfatal myocardial infarction, and recurrent angina leading to repeated coronary angiography. The analysis focused on patients with a culprit lesion (n = 270) and patients without a culprit lesion (n = 76) but with acetylcholine provocation (total n = 346).

RESULTS

In patients without culprit lesion, there was no cardiac death or nonfatal myocardial infarction during follow-up; 1 patient died due to a noncardiac cause. However, 38 of 76 patients reported persistent angina requiring repeated angiography in 3 cases (3.9%). Thirty of 270 patients with culprit lesion died due to a cardiac cause (11.1%) and 13 due to a noncardiac cause (4.8%). Eleven patients had nonfatal myocardial infarction (4.1%) and 27 repeated angiography due to persistent or recurrent angina (10%). Patients with a culprit lesion had a higher mortality and more coronary events compared with those without (p < 0.0005, log-rank test).

CONCLUSIONS

ACS patients without culprit lesion and proof of coronary spasm have an excellent prognosis for survival and coronary events after 3 years compared with patients with obstructive ACS. However, persistent angina represents a challenging problem in these patients, leading in some cases to repeated coronary angiography.

Disruption of coronary vasomotor function: the coronary spasm syndrome

Abnormal coronary vasoconstriction, or coronary spasm, can be the result of several factors, including local and neuroendocrine aberrations. It can manifest clinically as a coronary syndrome and plays an important role in the genesis of myocardial ischemia. Over the past half century, coronary angiography allowed the in vivo demonstration of spasm in patients who fit the initial clinical description of the condition as reported by Prinzmetal et al. Several clinical, basic, and more recently, genetic studies have provided insight into the pathogenesis, manifestations, and therapy of this condition. It is not uncommonly encountered in patients with coronary syndromes and absence of clearly pathologic lesions on angiography. Provocation tests utilizing pharmacologic and nonpharmacologic stimuli combined with imaging (echocardiography or coronary angiography) can help make the correct diagnosis. The use of calcium channel blockers and long-acting nitrates is currently considered standard of care and the overall prognosis appears to be good. The recent discovery of genetic abnormalities predisposing to abnormal spasm of the coronaries has stimulated interest in the development of targeted therapies for the management of this condition.

Non-ST-elevation acute myocardial infarction with normal coronary arteries: predictors and prognosis

INTRODUCTION AND OBJECTIVES

Occasionally, coronary arteries without significant stenosis are observed during invasive treatment of acute non-ST-elevation myocardial infarction (NSTEMI). The aim was to investigate predictive factors and prognosis in these patients.

METHODS

The study involved 504 patients admitted for NSTEMI who underwent cardiac catheterization. The primary end-point was the observation of coronary arteries without significant stenosis, and the secondary end-point was death or myocardial infarction within a median of 3 years. In evaluating the secondary end-point, a control group of 160 patients with a normal troponin level and no significant coronary artery stenosis who were admitted for chest pain during the same period was included.

RESULTS

Overall, 64 patients (13%) had coronary arteries without significant lesions. The predictors were: female sex (odds ratio [OR]=6.6; P=.0001), age <55 years (OR=3.0; P=.001), and the absence of diabetes (OR=2.4, P=.02), previous antiplatelet treatment (OR=3.9, P=.007) or ST-segment depression (OR=2.4, P=.008). The composite variable of female sex plus at least two additional predictive factors had a specificity of 85% and a sensitivity of 53% for coronary angiography showing no significant stenosis. The absence of coronary artery stenosis decreased the probability of death or myocardial infarction during follow-up (hazard ratio=0.3, 95% confidence interval, 0.2-0.9; P=.03). Among all patients without significant stenosis (n=224), there was no difference in the event rate between those with elevated and normal troponin levels.

CONCLUSIONS

In NSTEMI, female sex, age <55 years and the absence of diabetes, previous antiplatelet treatment or ST-segment depression were all associated with coronary angiography showing no significant stenosis. The long-term prognosis in these patients was good.

Non-ST-elevation acute myocardial infarction with normal coronary arteries: predictors and prognosis

INTRODUCTION AND OBJECTIVES

Occasionally, coronary arteries without significant stenosis are observed during invasive treatment of acute non-ST-elevation myocardial infarction (NSTEMI). The aim was to investigate predictive factors and prognosis in these patients.

METHODS

The study involved 504 patients admitted for NSTEMI who underwent cardiac catheterization. The primary end-point was the observation of coronary arteries without significant stenosis, and the secondary end-point was death or myocardial infarction within a median of 3 years. In evaluating the secondary end-point, a control group of 160 patients with a normal troponin level and no significant coronary artery stenosis who were admitted for chest pain during the same period was included.

RESULTS

Overall, 64 patients (13%) had coronary arteries without significant lesions. The predictors were: female sex (odds ratio [OR]=6.6; P=.0001), age <55 years (OR=3.0; P=.001), and the absence of diabetes (OR=2.4, P=.02), previous antiplatelet treatment (OR=3.9, P=.007) or ST-segment depression (OR=2.4, P=.008). The composite variable of female sex plus at least two additional predictive factors had a specificity of 85% and a sensitivity of 53% for coronary angiography showing no significant stenosis. The absence of coronary artery stenosis decreased the probability of death or myocardial infarction during follow-up (hazard ratio=0.3, 95% confidence interval, 0.2-0.9; P=.03). Among all patients without significant stenosis (n=224), there was no difference in the event rate between those with elevated and normal troponin levels.

CONCLUSIONS

In NSTEMI, female sex, age <55 years and the absence of diabetes, previous antiplatelet treatment or ST-segment depression were all associated with coronary angiography showing no significant stenosis. The long-term prognosis in these patients was good.

Menstruation angina: a case report

Introduction

Menstruation is commonly associated with migraine and irritable bowel but is rarely correlated with angina or myocardial ischaemia. Only a small number of cases have been reported suggesting a link between menstruation and myocardial ischaemic events.

Case presentation

A case of menstruation angina is reported in order to raise awareness of this association. A 47-year-old South Asian woman presented with recurrent chest pains in a monthly fashion coinciding with her menstruations. Each presentation was associated with troponin elevation. Angioplasty failed to resolve her symptoms but she eventually responded to hormonal therapy.

Conclusions

The possibility of menstruation angina should always be taken into account in any female patients from puberty to menopause presenting with recurrent chest pains. This can allow an earlier introduction of hormonal therapy to arrest further myocardial damage.