Abstract
A 28-year old man presented to the Emergency Department with malaise after cocaine intake. After arrival he developed retrosternal chest pain and the electrocardiogram showed ST segment elevations in V1-V2 and ST segment depressions in V5-V6. An acute coronary angiogram revealed a focal non-occlusive lesion with thrombus in the left anterior descending artery. Supplementary optical coherence tomography (OCT) detected plaque erosion with adherent thrombus to be the responsible underlying pathophysiological mechanism. The patient received an effective antithrombotic regimen. Repeat angiogram with additional OCT one month later documented thrombus resolution and complete restoration of the previously eroded coronary vascular surface area.
Highlights
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Optical coherence tomography (OCT) was used to characterize a coronary artery plaque.
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OCT detected coronary plaque erosion in a young male with MI due to cocaine abuse.
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OCT was used to document thrombus resolution.
1
Introduction
Cocaine is the illicit drug that leads to most visits at Emergency Departments and the prevalence of cocaine use worldwide is estimated between 14 and 21 million users, making cocaine among the most frequently used illicit drugs . The pathophysiology of cardiovascular effects due to cocaine includes stimulation of the sympathetic nervous system through inhibition of norepinephrine and epinephrine reuptake by sympathetic neurons, blocking of potassium and sodium channels, and promotion of thrombosis through different pathways . Cardiovascular complications are more frequent due to cocaine use rather than any other illicit drug and include aortic dissection, arrhythmias, cardiomyopathy and sudden cardiac death . Cocaine also causes arterial hypertension and increases heart rate thereby increasing myocardial oxygen demand and activates platelets and stimulates platelet agreeability thereby promoting formation of thrombus . Acute cardiovascular impacts are more common rather than chronic cardiovascular impacts following cocaine use and the most common complaint is chest pain, making angina the most prevalent clinical presentation among cocaine users in Emergency Departments .
Optical coherence tomography (OCT) is an optical intravascular high-resolution imaging modality, which can be used to visualize superficial intravascular proportions . OCT is analogous to intravascular ultrasound and works by using a light source with wavelengths between 1280 and 1350 nm measuring the backscattered light rather than the sound thereby producing cross-sectional images of e.g. coronary arteries . Determining the backscattered light in coronary arteries during acute myocardial infarction (MI), OCT can be used to characterize culprit lesions, plaques, potential ruptures, and differentiate between red, white and mixed thrombus. OCT produces near in-vivo histological images of the superficial layers of the coronary vessel wall, and is considered of greater accuracy to detect and characterize thrombosis than other intracoronary imaging methods .
Here we present a case in which OCT was used to characterize a coronary artery plaque and thrombus in a young male patient with ST segment elevation MI (STEMI) changes on the electrocardiogram (ECG) after cocaine intake.
2
Case
A 28-year old man was admitted to the Emergency Department due to vomiting, periodic convulsions in his toes, tachycardia and profuse perspiring after four days of severe use of cocaine, alcohol and marihuana. He had a history of 15 smoking pack-years, alcohol abuse drinking allegedly more than 100 units weekly, and a habitual use of sniffing cocaine. He had previously been diagnosed with medical required depression but refused to take antidepressant medicine as he found it too expensive. He had no co-morbidities such as hypertension, hypercholesterolemia, and diabetes mellitus. There were no previous cardiovascular complaints, and no known familial history of cardiovascular disease. ECG at arrival showed sinus rhythm and QT prolongation 520 ms. Paraclinical results revealed lactate levels at 3.5 mmol/L and hypokalemia with potassium levels at 2.9 mmol/L. Urinal drug screening was positive for cocaine and marihuana. Two hours after arrival at the Emergency Department the patient developed retrosternal chest pain radiating to the left arm, and a new ECG showed sinus rhythm and significant ST segment elevations in V1-V2 and reciprocal descending ST segment depressions in V5-V6. The patient was transferred to a heart center where treatment of an acute coronary angiogram was performed. The angiogram revealed a focal non-occlusive lesion with thrombus in the left anterior descending artery (LAD) ( Fig. 1 A and B ) without signs of peripheral embolization and the coronary blood flow was preserved (thrombolysis in MI (TIMI) flow grade 3). The patient was treated medically with unfractionated heparin (10.000 IU), abciximab and dual antiplatelet therapy with aspirin and ticagrelor. A control angiogram with supplementary OCT was performed two days later, where the angiogram still showed an eccentric intracoronary filling detect. OCT documented a moderately large red thrombus (high-backscattering protrusion with signal free shadowing) adherent just proximal to the first diagonal branch, and extending 10 mm further proximally. Significant pathological intimal thickening (PIT) with a maximum thickness of 750 μm was identified in relation to the adherent red thrombus. Underlying plaque erosion at this fibrous plaque site was speculated, but it was impossible to visually verify this suspicion further, as the thrombus-induced signal free shadowing prevented complete superficial vessel wall assessment. Previously, it has been proposed to categorize plaque erosion as definite, when “fibrous cap disruption is absent and thrombus is present” . At non-culprit sites, the vessel wall was predominantly characterized by a preserved trilaminar inapparent architecture ( Fig. 2 ).
One month later a control angiogram with OCT revealed thrombus resolution ( Fig. 1 C and D) and restored and smooth luminal contours without any signs of erosion. The PIT site was largely unchanged ( Fig. 3 ). The cross-sectional area image corresponding to the previous largest thrombus burden site was with an intact lumen contour, and without any signs of rupture, cavity or residual erosion.
