A comorbidity of cardiac atherosclerotic disease with cardiac myxomas being concomitantly treated by coronary artery bypass grafting coupling with tumor resection: a case report

Abstract

Introduction and importance:

Cardiac atherosclerotic disease (CAD), the leading cause to cardiovascular disease-related death, coexisting with cardiac myxoma, the commonest benign primary cardiac neoplasm, is rare. The treatment of the comorbidity is complicated due to the rarity and inexperience.

Case presentation:

A 65-year old male patient with intermittent chest tightness and shortness of breath for 10 years was admitted for further work-up. On admission, the comprehensive metabolic panel (CMP) revealed a normal liver, kidney and coagulant function, and the BNP, troponin and CK-MB were within the normal limits. ECG showed a sinus rhythm. Cardiac catheterization revealed a three-vessel disease of CAD. Incidentally, echocardiography and MRI found a mobile mass, highly suspicious of cardiac myxomas on the imaging, at the left atrium. A coronary artery bypass grafting (CABG) combining with a right-atrium approach resection of the lesion were devised and concomitantly performed. No surgical complications and major cardiac adverse events occurred post-procedure. After anti-infection and supportive care, the patient recovered uneventfully. Follow-up at 6 months revealed no discomfort of the patient.

Clinical discussion:

It was risky to treat the comorbidity separately. Due to the rarity of the comorbidity, it remains unsolved whether the prognosis will be truly affected by the concurrent procedures. Yet, this single case with a prosperous outcome post-surgery might provide a valuable reference to the treatment of cardiac myxomas incidentally diagnosed in CAD.

Conclusion:

The three-vessel CAD co-occurring with the single lesion cardiac myxomas at the left atrium can be managed safely and effectively by combining CABG with transseptal right atriotomy in the concomitant procedures.

Introduction

Cardiac atherosclerotic disease (CAD) is a prominent issue affecting the public health worldwide and a leading cause to cardiovascular disease-related death^[1]. The CABG is currently the most effective revascularization procedure to the occlusive coronary arteries, demonstrated to be superior over the other procedures in three-vessel disease by comparing the occurrence of myocardial infarction and the rate of repeated revascularization^[2].

HIGHLIGHTS

• A left atrium cardiac myxomas, the commonest benign primary cardiac neoplasms, incidentally diagnosed in CAD.

• The comorbidity of CAD with cardiac myxoma being rare.

• CABG indicated for three-vessel disease of CAD, class I evidence, complicated by the comorbidity.

• A CABG coupling with a surgical excision of the cardiac myxoma, through transseptal right atriotomy, being successfully performed.

• A prosperous outcome post-surgery providing the initial evidence for the safety and effectiveness of the combining open surgeries.

Cardiac myxoma is the most common benign primary cardiac neoplasm, accounting for about 50% of all adult cases^[3]. It occurs most frequently at the left atrium, where about 75% of all the diagnosed cases are found^[4]. The clinical manifestations are various according to the size, location, number and growth speed of the tumor. The symptoms are not specific to the condition that cases can be diagnosed incidentally by imaging studies for other indications or routine examinations. Notably, obstruction and embolization of cardiac myxoma can lead to lethal consequence of sudden death of the patients. Therefore, prompt surgical excision is indicated at the diagnosis of cardiac myxomas^[5]. It is rare that the cardiac myxoma is diagnosed incidentally with CAD and then treated concomitantly in one procedure. Our case hereby presented a comorbidity of the two conditions and highlighted a successful treatment of combining CABG with right-atrium approach tumor resection in concomitant procedures.

This case has been reported in accordance with the SCARE guidelines^[6].

Case presentation

A 65-year old male patient complained of an intermittent chest tightness and a shortness of breath for 10 years, getting worse for 1 day, and was admitted for further work-up. The discomfort often lasted for minutes before being relieved, and could be provoked by physical exertion or activity. Occasionally, he would have nocturnal orthopnea. The symptoms could be relieved by themself until they were getting worse upon admission. No palpation, nausea and vomiting were found with the major complaint. There was a history of high blood pressure that could be well controlled by oral medications. The patient had had a history of smoking, taking about 10 cigarettes per day, for 40 years. There was no smoking cessation even being attempted. And he had no history of alcohol consumption. No family history of cardiovascular disease or cardiac tumors had been documented. On admission, the physical examinations revealed the vital signs being stable as T 36 Celsius, P 71 bpm, R 18 bpm, BP 117/67 mmHg. No corneal arcus and retinal arteriolar were detected. The skin was normal as well. No heart murmur was detected. And no elevated jugular venous pressure, pulmonary rales and peripheral edema were found.

A coronary CTA was initially ordered at the outpatient department and showed that the LAD, circumflex artery, and right coronary artery were narrowing. After the admission, the ECG showed a sinus rhythm with a normal ST segment. The CMP revealed a normal liver, kidney, and coagulant function, and the electrolytes were within normal limits. TG was 2.6 mmol/L higher than normal. And the BNP, troponin and CK-MB were all within normal limits at admission. US to heart function revealed normal ejection fraction. Supported by this results, a treatment of anti-platelet and statins was initiated, and a cardiac catheterization for further test was ordered.

The cardiac catheterization was completed and showed the narrowing of the coronary arteries: the LM, the proximal and middle LAD, the diagonal branch, and the base and proximal vessel of LCX were constricted by 85%, 75%, 99%, 80%, 75%, and 85%, respectively, in vessel diameters; the RCA was constricted about 50% and the posterior interventricular branch was about 70% obstruction both in luminal diameter (Fig. 1). It was distinguished as a three-vessel CAD.

Figure 1.

Cardiac catheterization. (A) The end of LM was constricted by 85% in luminal diameter (white arrow). (B) The proximal and middle LAD, the diagonal branch, and the base and proximal vessel of LCX were obstructed by 75%, 99%, 80%, 75%, and 85%, respectively, in diameters (white arrow). (C and D) The RCA and the posterior interventricular branch narrowed about 50% and 70% both by luminal diameter.

Notably, the imaging studies of the work-up incidentally detected a left atrium mass. Echocardiography detected a heterogeneous mobile mass revealed as a moderate hyperechoic lesion protruding to the left atrium chamber about 1.3 by 1.0 cm around the top of left atrium (Fig. 2A). MRI revealed a round form mass about 12 mm being isointense at T1 weighted and hyperintense at T2 weighted on the side of left atrium septal (Fig. 2B). With the above imaging features, a diagnosis of cardiac myxomas was highly suspicious.

Figure 2.

Echocardiography and MRI. (A) Echocardiography detected a heterogeneous mobile mass at the left atrium. (B) MRI revealed a round-like mass about 12 mm isointense at T1 weighted and hyperintense at T2 weighted on the side of the left atrium septal (white arrow).

After evaluation, an on-pump CABG combining with an excision of the highly suspicious cardiac myxomas lesion were planned and then successfully performed. Briefly, the surgery was performed in a supine position. After the establishment of general anesthesia and draping, a median sternotomy was operated to expose the heart. Once the heart being exposed and the patient being heparinized, the procedure of on-pump cardiopulmonary bypass was initiated from the cannulation of the ascending aorta and the right atrial appendage for the superior and inferior vena cava drain. A purse-string was created to tighten the inserted cannulas. The ascending aorta cannula was first inserted, and then was the antegrade cardioplegia cannula into the ascending aorta. The cannulation of superior vena cava was first established and then the inferior vena cava. After an antegrade cardioplegia completed for cardiac arrest, the right atrium was incised open along the line of superior and inferior vena cava. The right atrium was exposed and then the fossa ovalis was cut open to enter the left atrium, where the mass was found about 2.0 by 1.0 cm with the body and head protruding to the top of the right atrium and the base rooted on the atrial septal. The surface and the borderline of the mass were smooth and clear. The mass was then completely incised from the base and the left atrium was carefully explored for residual lesions before closing. 4-0 suture was used to close the atrial septal. On completion, the cardiopulmonary bypass took 70 min and the aorta was blocked for 32 min. The mass was sent for pathological examination, which confirmed the diagnosis of cardiac myxoma (Fig. 3). Following it, a CABG was then performed successfully. The great saphenous vein was harvested and prepared. The saphenous vein was anastomosed sequentially to the ascending aorta and the middle of LAD. Notably, the collateral flow of the diagonal branch was formed substantially after exploration; therefore, it was left untreated.

Figure 3.

Pathological examination. (A) The mass appeared as a round nodule with a smooth surface and a red and gray core. (B) Microscopically, H&E staining revealed that the polygonal cells of myxoma were arranged in cords and nests surrounded by mucinous matrix and stroma. The slides also revealed local bleeding, muscle tissue degeneration, and inflammatory cells infiltration. (C and D) The immunohistochemistry of CD 34 and Vimentin showed positive staining in brown color, the presence of the markers together with the HE staining pointing to the diagnosis of cardiac myxomas.

After the surgery, the patient was immediately transferred to the Intensive Care Unit while intubated and unawakened for close monitoring and prompt response. And a ventilator was used there for a while. Post-surgery treatment mainly included anti-infection, supportive care, anti-clotting, analgesics and sedation. Lab tests were ordered to monitor the vital organs and recovery. No surgery related complications occurred. On the fourth day post-surgery, the patient was moved back to the regular ward while the physiological functions of vital organs returned to normal and were kept stable after the acute phase, and the anti-coagulation started from then on. The following 2 weeks were spent in the regular ward for cardiac rehabilitation until his discharge on the 19th day post-surgery. The recovery process was uneventful. And 6-month follow-up revealed no discomfort of the patient.

Discussion

The primary cardiac neoplasms are very rare, of less than 0.1% found during large autopsies and of 70% cases being benign with a female preference^[7,8]. Cardiac myxomas is the most common benign primary cardiac neoplasm, of which the left atrium is the preference site. The neoplasm usually originates from the marginal region of the fossa ovalis. It can be either sporadic or familial. The lesion may be single or multiple and even multicentric. The familial cardiac myxoma has a high tendency of recurring after resection. The papillary lesion of myxomas is gelatinous and fragile, and prone to embolization^[9–11].

The current knowledge elucidates that the cardiac myxoma is originated from the pluripotent mesenchymal cell. Microscopically, stellated fusiform and polygonal cells and multinucleated cells are visualized to occupy the lesion in myxoid like stroma. And the form of chained rings or nests can be observed around the capillaries. On the surface of the neoplasm, a layer of endothelium is visualized present. Immunohistochemically, the biomarkers of CD32, CD34, CD56, FVIIIAg, S-100 protein, calretinin, vimentin, desmin, smooth muscle myosin, a1 antitrypsin and alpha 1-antichymotrypsin have been found positive in the lesion^[12].

The symptoms and signs are nonspecific. The diagnosis is made incidentally in as high as 50% cases by imaging studies for other indications or routine cardiac imaging studies^[5]. The location, size, and mobility of the myxomas dictate the clinical presentations typified by intracardiac obstruction, embolization and constitutional symptoms. The symptoms mimic mitral stenosis for the detachment of the lesion from the left atrium, the most common diseased site, can obstruct the outlet of the mitral. The patients may present syncope, or even develop left heart failure. The right heart chamber lesion, less common site, can lead to the right heart obstruction or failure^[13]. Imaging studies can help find the neoplasm. Ultrasound (US) is usually the first modality to detect the presence of a lesion. The typical feature of cardiac myxomas on the imaging of US presents as a solid mobile mass with the base pedunculated to the atrium septum. MRI can further reveal the lesion for evaluation to devise a proper surgery, where the size and shape and the location of the lesion can be shown more clearly with an isointense mass at T1 weighted and a hyperintense at T2-weighted imaging and the core of the mass being hypointensity on both T1 and T2 imagings^[14,15].

In this case, the CAD was the first diagnosis with the cardiac myxomas found incidentally on the following imaging studies. The comorbidity is rarely encountered in practice. Therefore, the management is inexperienced, and the prognosis remains to be unanswered. In CAD, the typical symptom remains to be angina pectoris, which is usually depicted by patients as being squeezing and viselike chest pain. Notably, it can be atypical in women and elderly^[16,17]. The chest discomfort presents more severely, lasts longer and cannot be relieved by sublingual nitroglycerin, or occurs at rest or nocturnal, most likely heralding the presence of an acute coronary syndrome (ACS) or a myocardial infarction (MI). The complications of ventricular septal defect, mitral papillary muscle rupture, and free ventricular rupture may present after MI. And cardiogenic shock often indicates a poor prognosis with a high mortality^[18,19]. Physical examination has little value in distinguishing the diagnosis. A holosystolic or mid-late systolic apical murmur may indicate mitral regurgitation resulted from reversible papillary muscle dysfunction. The signs of elevated jugular venous pressure, pulmonary rales, and peripheral edema are linked with heart failure^[20].

Although ECG and serum biomarkers have values in diagnosing CAD, there are not without limitations. ECG may not reveal ST segment depression or elevation or T wave inversion in stable cases, where collateral circulations have been well established to compensate the demand of oxygen at rest. The troponin can be detected as early as 2 hours after the onset of the symptoms, but delays of up to 8 hours before elevation has also been observed in some cases, requiring repeated tests in clinical practice^[21]. These traditional lab tests have been criticized for reaching a limit in the prevention of the incidence of CAD; however, the novel noninvasive testings still await to be developed in clinical practice^[22].

Coronary catheterization remains to be the “gold standard” in the diagnosis of CAD. The coronary artery is anatomically classified as LAD, the circumflex, and the RCA that have been established decades ago and are still used at present^[23,24]. Coronary angiography has been standardized and can reveal the location, length, diameter and contour of the epicardial coronary arteries, where the coronary blockage can be detected and assessed and collateral flow be visualized^[25]. In our case, the coronary catheterization revealed a three-vessel CAD, where the ECG and troponin did not show severe abnormality, indicating that a network of “backup” vessels could compensate for the myocardium demand of oxygen at rest and help reserve the heart function to endure the surgery.

In the most recent guidelines of American College of Cardiology, except acute ST-elevation myocardial infarction, CABG has a superior class over the other interventions in treating CAD. Class I indications for CABG include unprotected left main, three-vessel disease with or without proximal LAD, two-vessel disease with proximal LAD^[20]. A large-scale and longer follow-up study has compared CABG with PCI (with drug-eluted stent) for three-vessel or left main CAD, revealing that CABG has superior class in terms of lowering MI occurrence and repeated revascularization in the complicated CAD cases^[26]. Notably, the CABG needs to assess the distal end of the vessel at first. Should the distal end of the vessel be severely restricted there will be less chance to bypass the restriction and conduct enough blood flow to the myocardium. In our case, the distal sides of the restricted vessels were left wide open for enough blood flow by the initial evaluation and the CABG was indicated. Yet, the operation was complicated by the incidental discovery of a highly suspicious cardiac myxomas at the left atrium. The coexisting of cardiac myxomas with CAD have been reported^[27,28]. Notably, coronary artery endothelial injury plays an important role in the pathogenesis of CAD, and inflammatory response and lipid deposition can induce the injury^[29]. The cardiac myxoma and the CAD in our case may share a common inflammatory pathway that contributes to the progress of the comorbidity. It will be interesting that basic studies can explore the pathogenesis from the point of inflammatory cytokines, for instance, the mucinous tumors, cardiac myxoma, can secrete IL-6 and/or other related cytokines, that can promote the coronary atherosclerosis. The optimal treatment for this comorbidity has not yet been explored. For cardiac myxomas, a prompt surgery is often recommended to avoid a disastrous embolization caused by the detachment of the fragile lesion possibly occurring at any time^[11]. Surgical excision may be performed through a biatrial approach, or a transseptal approach with right atriotomy and septotomy, or a left atriotomy according to the size and location of the lesion^[30,31]. In our case, the root of the tumor was attached to the atrium septum with the head pointing to the top of the left atrium. Therefore, the transseptal approach with right atriotomy, most likely shortening the access to the tumor and accomplishing a complete resection, has been chosen to excise the tumor. And the four chambers can also be well explored by this approach. In addition, the right atrium approach can avoid damaging the Bachmann’s bundle (the interatrial bundle), branching to the roof of the left atrium, and protect the function of the left atrium. By contrast, the biatrial approach is more suitable for larger size tumors. The disadvantages of the right atriotomy approach are obvious in this case, where the cut through the posteria interatrial groove is comparatively far from the lesion and exposing the lesion can increase the risk of the fragile lesion detachment leading to embolization, and the function of the left atrium can also be damaged. Although the CABG coupling with right atriotomy approach has been successfully performed with a prosperous outcome in our patient, it should be noted that the cardiac myxomas was not a complex lesion, but a single and comparatively small one, which tremendously eased the surgical procedures. For multiple and other chamber lesions, the treatment needs to be evaluated individually and a totally different approach may be devised to treat the tumors with various sizes and locations.

Notably, the questions that need to be answered are whether the excision of cardiac myxomas coupling with CABG can increase the risk of the latter one, and how the prognosis will be affected if the comorbid conditions are treated separately. And a large-scale data exploring the feasibility, safety, effectiveness and prognosis are lack due to the rarity of the comorbidity. This single case demonstrated the CABG combined with the cardiac myxomas excision in one single procedure were safe and effective in treating the comorbidity. No major cardiac event occurred post-procedure, and the recovery process was prosperous after 6 months. Yet, a longer follow-up awaits to find out the long-term outcome of the joining procedures and the recurrence of the tumor.

Conclusion

Cardiac myxomas can co-occur with CAD. It is rare that the comorbidity is treated by the concomitant surgeries. For the left atrium cardiac myxomas with a single lesion, the right atrium approach surgery through right atriotomy and septotomy is safe to be performed concurrently with the CABG for the three-vessel CAD.

Ethical approval

Not applicable.

Consent

A copy of the written consent form is available for review on request.

Sources of funding

None.

Author contributions

C.H.: the first author, completed the manuscript draft and data collection. F.L.: the corresponding author, conceptualized the paper and edited the manuscript. N.G. and J.W.: contributed equally to the manuscript as a surgical team. M.X.: contributed to the revised manuscript by modifying the high-resolution photos of all the figures. All the authors read and approved the submission of this manuscript.

Conflicts of interest disclosure

The author declares no conflict of interest.

Research registration unique identifying number (UIN)

Not applicable.

Guarantor

Puren Hospital.

Provenance and peer review

Not commissioned, externally peer-reviewed.

Data availability statement

All submitted data are available for public access.