Acute coronary syndrome secondary to cardiac infiltration and coronary occlusion of chronic lymphocytic leukemia – A case report

Abstract

A 72-year-old male with a history of chronic lymphocytic leukemia (CLL) was admitted to hospital with a productive cough and an episode of diarrhea and vomiting. He was initially treated for pneumonitis and sepsis. On the 12th day of his admission, he reported chest pain. Changes on his electrocardiogram were suggestive of myocardial ischemia and an elevated troponin rise was detected from his blood tests. A diagnosis of acute coronary syndrome was made but due to his frailty, he was medically managed. His echocardiogram revealed an external echogenic mass which invaded the anterolateral left ventricular wall. Further imaging with cardiac magnetic resonance imaging (MRI) and computed tomography (CT) thorax demonstrated external encasement of left circumflex coronary artery with mediastinal mass, leading into downstream myocardial ischemia and subsequent necrosis. He was considered suitable for aggressive radiotherapy/chemotherapy but passed away 7 days later. This case highlights the unusual case where an acute myocardial infarction can be attributed to direct infiltration and external compression of coronary artery by mediastinal tumor and the value of multi-modality imaging (echocardiogram, CT, and MRI) in identifying the cause of myocardial ischemia in patients with CLL in the end stages of the disease.

<Learning objective: It is unusual that acute coronary syndrome is caused by direct tumor infiltration and obstruction of a major epicardial vessel. This case highlights the interesting and unusual scenario where tumor growth results in complete occlusion of the obtuse marginal coronary artery in a patient with chronic lymphocytic leukemia. By using multi-modal imaging, we were able to characterize the lesion and the coronary involvement.>

Introduction

Chronic lymphocytic leukemia (CLL) is a malignancy of CD5⁺ B cells where there is an accumulation of mature-appearing neoplastic lymphocytes which can accumulate in the peripheral blood, bone marrow, and lymphoid tissues [1]. The complications in CLL relate to the spread of malignant cells, which commonly involve spleen and liver. In advance stages of CLL, the neoplastic cells may invade other organs including prostate, pituitary, thyroid glands, and myocardium [2]. There are rare case reports of acute myocardial infarction as the result of microvascular obstruction secondary to direct leukemic infiltration and vasoconstriction, with minor epicardial coronary artery luminal stenosis [3,4]. Here, we present a patient with known CLL who, during an admission with suspected recurrent pneumonitis, later developed an acute coronary syndrome caused by direct infiltration and obstruction of a major epicardial vessel.

Case report

A 72-year old Caucasian man presented to the accident and emergency department complaining of feeling generally unwell with a productive cough and an episode of diarrhea and vomiting. He was under surveillance for CLL and autoimmune hemolytic anemia. In addition, he had bronchiectasis and recurrent Klebsiella infections. His other comorbidities included previous transient ischemic attack and type 2 diabetes mellitus. He lived with his wife and was normally an independent, non-smoker and did not consume alcohol.

On examination he was found to be febrile (38.0 °C), tachycardic (123 beats/min), tachypneic (25 breaths/min), with reduced air entry to the left base of the lungs and widespread crepitations on auscultation of both lung fields. His blood pressure was 100/46 mmHg. He was hypoxic on arrival and his oxygen saturations became stable at 100% on 15 L of oxygen. The working diagnosis was recurrent pneumonitis.

His blood test showed hemoglobin 116 g/L, white cell count 9.2 × 10⁹/L, a low platelet count at 43 × 10⁹/L, profound neutropenia at 1 × 10⁹/L, raised C-reactive protein 109 mg/L, estimated glomerular filtration rate >90/min/1.73 m², K 4.6 mM, Ur 8.7 mM, and the venous blood gas showed pH 7.39, pCO₂ 4.58 kPa, lactate 2.7 mM, and HCO₃⁻ 21 nM.

His electrocardiogram was reported by the team reviewing as sinus tachycardia, rate: 150 bpm with no significant ST or T wave changes (Fig. 1A).

Fig. 1.

(A) Electrocardiogram (ECG) on admission. (B) Chest X-ray on admission. (C) ECG during chest pain.

The chest X-ray demonstrated a left-sided chest wall opacity (Fig. 1B). He was started on intravenous hydrocortisone the next day with a provisional diagnosis of neutropenic sepsis, infection originating from chest. Blood cultures were obtained.

On day 12 of admission the patient fell in the bathroom, on questioning he reported having central chest discomfort, rate 5/10 in severity which caused him to fall. An electrocardiogram was performed which demonstrated 1 mm ST segment elevation and T wave inversion in leads I and aVL, as well as V4 to V6, compatible with high-lateral myocardial infarction, with repolarization abnormities (Fig. 1C). It was noted that the treating doctor highlighted the inferolateral T-wave inversion but there were typical changes consistent with an evolving high lateral ST-elevation myocardial infarction likely in the left circumflex territory. His troponin I was checked and was found to be significantly elevated at 1613 ng/mL; the patient was started on acute coronary syndrome regimen with dual antiplatelet, high-dose statin. As the patient's symptoms had settled analgesia and nitrates were not commenced. An urgent echocardiogram was requested.

The echocardiogram showed an echogenic mass surrounding anterolateral left ventricular epicardial space, potentially infiltrating into the myocardium (Fig. 2). There was a normal size left ventricular cavity with moderate left ventricular systolic impairment, due to antero-apical and lateral regional wall motion abnormality. Estimated left ventricular ejection fraction was calculated to be 40–44%. A computed tomography (CT) of the thorax, abdomen, and pelvis was arranged as well as a cardiac magnetic resonance imaging (MRI) scan.

Fig. 2.

(A) Apical four-chamber view of myocardial mass invasion into the apical antero-lateral LV region on echocardiography. (B) Apical two-chamber view of myocardial mass invasion into the apical anterior LV region on echocardiography.

LV, left ventricle; LA, left atrium; RV, right ventricle.

Fig. 3a shows the axial portovenous phase CT scan showing pericardial and myocardial invasion by the necrotic mass, also extending through the chest wall. The full scan was reported as showing a widening left hilar mass, now extending into the pericardial space with further epicardial infiltration. The mass also extended into the sternum, left hemi-thorax lower ribs, and the pulmonary space including infiltration of the lingular segments and bronchial branches. Left lower lobe consolidation was seen which could be either the result of direct infiltration, or atelectasis related to mucous plugging. The overall appearance of the mass suggested a liquefying solid lesion, infected and/or purely necrotizing malignancy. There was a stable small non-dependent left pleural effusion and a smaller right mild pleural effusion. The impression was significant progression in left hilar malignancy with extension in the left ventricular myocardial, chest wall and left lung compared to previous scans.

Fig. 3.

(A) Axial portovenous phase computed tomography images showing the mass invading the left ventricle. (B, C) Four-chamber images from the cardiac magnetic resonance imaging showing the mass invading the left ventricle. (B) 4-chamber STIR images. (C) 4-chamber early gadolinium images. (D-F) Short-axis images from the cardiac magnetic resonance imaging showing the mass invading the left ventricle. (D) Short-axis T2 STIR images. (E) Short-axis steady-state free procession cine images. (F) Short-axis late-gadolinium enhancement images.

Images from the patients cardiac MRI scan are shown in Fig. 3B–F. Fig. 3B illustrates the four chamber T2-weighted STIR images showing invasion of the lateral wall of the left ventricle. Fig. 3C shows the four-chamber early gadolinium enhancement and edema in the mid-to-apical left ventricular lateral wall. Fig. 3D shows the short-axis T2-weighted STIR images showing the invasion of the lateral wall of the left ventricle. Fig. 3E shows the short-axis steady-state free procession cine which depicts the myocardial thinning and akinesia in systole. Fig. 3F shows the short-axis late-gadolinium enhancement demonstrating the mid-inferolateral transmural scarring in the area of thinning and akinesia.

The cardiac MRI was reported as good volumes for both left and right cardiac ventricles with impaired left ventricular systolic functional impairment secondary to mass invasion of the lateral wall. The large mass with central necrosis extended over the left hemithorax, mediastinum, left lung, anterior chest wall, pericardium, and finally left ventricular myocardium at the lateral wall. The lateral left ventricular wall showed increased T2 signal on STIR in keeping with myocardial edema as well as infiltration on cine images, supplemented by the observation of abnormal early gadolinium uptake. In addition to changes related to external cardiac mass, there was abnormal rest perfusion, along with late gadolinium enhancement in mid to apical lateral wall, in keeping with superadded myocardial infarct. Location of the infarct and its relationship with mass suggested myocardial infarction related to obtuse marginal branch occlusion with extrinsic infiltration.

In view of his reduced general health, physiological status, the patient was managed conservatively. A tissue diagnosis through ultrasound-guided biopsy was considered, however risk/benefit balance once again dictated a more conservative approach. The patient's general health gradually declined. Palliative care team's input was obtained with his family's consent and the patient passed away peacefully a month after his admission. Cause of death was attributed to end stage CLL, to the best of our knowledge there were no episodes of heart failure or cardiac arrythmias.

Discussion

This case report describes a myocardial infarction due to extrinsic compression of the coronary arteries secondary to CLL-derived mediastinal mass. We show how different cardiac imaging modalities can be useful in evaluating mass and elucidate various mechanisms leading to myocardial infarction and coronary obstruction.

The true incidence of myocardial infiltration of CLL is unknown with only one single center experience being published on organ infiltration rates of CLL patients [5]. Of the 47 included patients, 64% (25 patients) had myocardial involvement and 14 patients had infiltration within the epicardium, 18 within the myocardium, and 12 within the endocardium. Furthermore, as patients with cardiac involvement are often asymptomatic, there are limited published case reports of myocardial involvement of CLL. Of the published cases, CLL infiltration of the endocardium and myocardium was attributed to a patient's death secondary to myocarditis and ensuing heart failure [6]. In two further cases, acute myocardial infarctions occurred secondary to severe atherosclerotic changes with infiltrated CLL cells within the adventitia and media of coronary arteries [7,8]. Our case highlights the finding that CLL in the end stages can also results in a large accumulation of malignant cells which can lead to encasement and subsequent occlusion of a coronary vessel and myocardial infarction.

The combination of CT, cardiac MRI, and echocardiogram imaging modalities was useful in this case to ensure a comprehensive assessment of CLL. Once the acute coronary syndrome diagnosis was suspected, an echocardiogram is often the first-line imaging modality of choice to assess the cardiac structure and function of the myocardium [9]. However, as seen in this case, there are instances where echocardiogram is limited in characterizing a myocardial mass invading the ventricular wall and further assessment with the use of cardiac MRI and CT imaging complemented assessment. Cardiac MRI offered tissue characterization for the mass, as well as enabling assessment of full extent of myocardial invasion and evaluation myocardial viability. CT thoracic imaging is integral to CLL patients’ management for staging of the disease [10]. While not performed, a CT coronary angiogram could have been helpful in assessing coronary anatomy and patency, which cannot be evaluated with cardiac MRI.

In conclusion, this case of a patient with CLL highlights the interesting and unusual scenario where tumor growth results in complete occlusion of the obtuse marginal coronary artery. By using multi-modal imaging, we were able to characterize the lesion and the coronary involvement. Unfortunately, the patient had significant spread of his CLL so it was decided that it was best that he would be medically managed and he died.

Declaration of Competing Interest

There are no competing interests.