Multifactorial Genesis of a Seeming Case of Pulmonary Hypertension.

Herein, we report the case of a 44-year-old female with end-stage renal disease on hemodialysis. She was admitted to our hospital to evaluate if she was eligible for a kidney transplant. Transthoracic echocardiography showed a markedly dilated coronary sinus and an unexpected finding of increased right ventriculoatrial gradient. A saline contrast echocardiography to confirm the presence of persistent left superior vena cava (PLSVC) was not performed because of arteriovenous fistula (FAV) for hemodialysis on the left forearm. Therefore, computed tomography angiography was performed, and it showed the PLSVC. We also proceeded with a transesophageal echocardiography which showed an atrial septal defect (ASD) of the sinus venous type hemodynamically significant. In this case, we identified a rare association of PLSVC with a ASD; therefore, there is a right ventricular volume overload because of the ASD hemodynamically significant and high flow FAV leading to a condition of a seeming pulmonary hypertension.

INTRODUCTION

Persistent left superior vena cava (PLSVC) is one of the most common venous anomalies of the thorax. However, the incidence is in <0.5% in the general population but occurs in approximately 4% of patients with congenital heart disease (CHD).[1] Sinus venous atrial septal defect (ASD) accounts for 4%–11% of all ASDs. The association between PLSVC and sinus venous type ASD is very rare.[2] Sinus venous type ASD, if left unrepaired, may eventually lead to right heart volume overload. Herein, we describe a case of PLSVC identified in a patient with markedly dilated coronary sinus (CS) and a rare association with sinus venous type ASD.

CASE REPORT

A 44-year-old female was hypertensive treated with ramipril 5 mg twice daily. She had a family history of kidney disease and a medical history of IgA nephropathy (Berger's disease). Then, she had become uremic, requiring chronic hemodialysis due to renal failure following Berger's disease for 8 years. Furthermore, an arteriovenous fistula (FAV) was created in the left forearm. Following hemodialysis training, the patient performed hemodialysis three times a week at home.

She had been hospitalized at the Nephrology Department 1 year previously because of bilateral pleural effusion and fever during hemodialysis.

Then, she was admitted to our hospital to evaluate if she was eligible for a kidney transplant. At the admission, the patient was asymptomatic. There was a mild leg swelling. On clinical examination, she was apyretic with a pulse rate of 96/min, blood pressure of 150/100 mmHg, and arterial saturation of 96%. On cardiac examination, we found normal first heart sound, fixed splitting of the second heart sound, hardening P2, and pansystolic murmur four of six in left parasternal line of intercostal space II–III. On lung auscultation, vesicular breath sound was heard over the most of the lung surface. Laboratory tests showed serum creatinine 9.91 mg/dl, serum urea 191 mg/dl, serum potassium 5.6 mmol/l, serum phosphorus 5.9 mg/dl, and Hb 9.5 g/dl.

Her electrocardiogram showed sinus rhythm of 90 bpm. Transthoracic echocardiography (TTE) showed enlargement of the right ventricle (right ventricular basal diameter of 51 mm) [Figure 1c] and truncus of pulmonary artery (diameter of 36 mm), a markedly dilated CS: 25 mm × 21 mm (normal value: <15 mm) [Figure 1a and b], mildly enlarged left atrium (42 mm parasternal long axis), normal size left ventricle (42 mm), and mild ejection fraction reduction (50%) along with altered diastolic pattern (Grade 1 diastolic dysfunction). There were also moderate mitral regurgitation and evidence of right ventricular volume overload with right ventricular-right atrial gradient of 43 mmHg [Figure 1d], tricuspid regurgitation of 3.4 m/s with estimate pulmonary artery systolic pressure of 65 mmHg. There was also a mild pericardial effusion.

Figure 1

(a) Two dimensional-transthoracic echocardiography: Parasternal long axis view in systolic phase showing left atrium, inferolateral wall of the left ventricle, the anteroseptum, and the right ventricular outflow tract. The red arrow shows a markedly dilated coronary sinus (diameter 21 mm × 25 mm) in the posterior atrioventricular groove. (b) Two-dimensional-transthoracic echocardiography: Apical 2-chamber view in systolic phase demonstrating left atrial and inferior and anterior walls of the left ventricle. The red arrow shows a markedly dilated coronary sinus. (c) Two-dimensional-transthoracic echocardiography: Modified apical 4-chamber view in diastolic phase showing an enlargement of the right ventricle (right ventricle basal diameter of 51 mm). (d) Two-dimensional-transthoracic echocardiography: Apical 4-chamber view in systolic phase showed a right ventricular volume overload with right ventricular-right atrial gradient of 43 mmHg and tricuspid regurgitation 3.4 m/s

We also proceeded with a transesophageal echocardiographic (TEE) study which demonstrated a septal defect of the sinus venous type, ranging 18–20 mm [Figure 2a and b], with normal return of the pulmonary veins. The resulting left-to-right shunt is hemodynamically significant with Qp/Qs: 2.2 (systemic blood flow of 7.6 l/min and pulmonary blood flow of 17.4 l/min due to the association of ASD and FAV).

Figure 2

(a) Transesophageal echocardiography: Bicaval view shows right atrium, caudal inferior vena cava (left), cephalad superior vena cava (right), and sinus venous interatrial septum (red arrow) defect (ranging 18–20 mm). (b) Transesophageal echocardiography: Bicaval view with color-flow Doppler that shows the hemodynamically significant shunt left-to-right side. (c) Computed tomography angiography: Lower transversal section shows persistent left superior vena cava (red arrowhead). The red arrow shows the hemiazygos vein which terminates in the lower end of the left superior vena cava. (d) Computed tomography angiography: Transversal section shows persistent left superior vena cava draining into the right atrium through a dilated coronary sinus (red arrow)

Dilatation of the CS raised suspicion of PLSVC. A saline contrast echocardiography to confirm the presence of PLSVC was not performed because of FAV on the left forearm. Therefore, computed tomography (CT) angiography was performed, and it showed the PLSVC draining into the right atrium through a dilated CS [Figure 2c and d].

Right heart catheterization (RHC) was performed to better estimate the magnitude of the shunt (pulmonary to systemic flow ratio, Qp: Qs) and measurement of the pulmonary artery pressure. The results of the RHC revealed a mean pulmonary arterial pressure of 21 mmHg, a pulmonary artery wedge pressure of 13 mmHg, and a pulmonary vascular resistance of 2.6 Wood units. Therefore, the RHC ruled out the diagnosis of precapillary pulmonary hypertension. There was only a right ventricular volume overload because of the ASD hemodynamically significant and high flow fistula. During RHC, oxygen saturations of single blood specimens were measured from the PLSVC, right atrium, and pulmonary artery. The oxygen saturations in PLSVC were 99% because of the FAV on the left forearm; in the right atrium, mid-high was higher than normal value, ranging from 98% to 95%, because of the shunt determined by the ASD. At the right atrium low, near tricuspid valve, there was an oxygen saturation of 80% for the reason why it received deoxygenated blood from the body through the inferior vena cava (O2: 56%).

Now, the patient is waiting for the elective surgery for ASD closure.

DISCUSSION

PLSVC is the most common thoracic vein anomaly, occurring in approximately 0.3%–0.5% of the normal population[3] and about 3%–10% in those with CHD, most commonly in association with septal defects or complex malformations, and in some cases with isomerism.[3] In about 90% of cases, bilateral superior vena cava exist; the absence of right superior vena cava is uncommon.[4] There are variable insertions of the PLSVC. It drains into the right atrium through the CS in 80%–90% of individuals, resulting in no hemodynamic consequence, but can cause a right-to-left-sided shunt when it drains into the left atrium by unroofed CS or, more rarely, directly.[5]

PLSVC should be suspected whenever a dilated CS is discovered on TTE or other imaging modalities. CS dilatation can result from various forms of anomalous venous communication such as PLSVC drainage into CS, total anomalous pulmonary venous return with CS drainage, coronary FAV with drainage into the CS, and the CS ASD. Other causes include right ventricular dysfunction, RA hypertension, and severe pulmonary hypertension.

The CS is best visualized in the parasternal long-axis view as a circular structure of approximately <1 cm in diameter in the posterior atrioventricular groove.

The presence of PLSVC can be confirmed by saline contrast echocardiography. Other modern imaging modalities such as CT or magnetic resonance imaging can be used to confirm the diagnosis. The enhancement of dilated CS before the right atrium following the injection of contrast into the left arm vein is echocardiographic criterion for PLSVC diagnosis, but in this case was performed CT angiography.

PLSVC has practical implications when performing procedures such as RHC or new therapeutic techniques that make the use of the cardiac veins overlying the left ventricle such as left ventricular pacing or percutaneous in situ coronary venous arterialization.[56] PLSVC can complicate permanent pacemaker and implantable cardioverter defibrillator placement. Serious complications such as arrhythmia, cardiogenic shock, cardiac tamponade, and CS thrombosis have been reported when pacemaker leads or catheters have been inserted through PLSVC.[5] During the diagnostic procedure for our patient, ASD, another congenital anomaly, and an unexpected finding of increased right ventriculoatrial gradient were found. Sinus venous ASD, originally described in 1858, encompasses approximately 4%–11% of ASDs.[7] The typical malformation is an interatrial communication caused by a deficiency of the common wall between the superior vena cava and the right-sided pulmonary veins. Sinus venous type ASD is commonly associated with anomalous pulmonary venous connection of some or all of the pulmonary veins,[8] which produces additional left-to-right shunting.

It may be asymptomatic in childhood but may become symptomatic with age. Unrepaired sinus venous ASD eventually leads to right heart volume overload and can ultimately lead to hypertensive pulmonary vascular disease, which was absent in our patient. TEE improves diagnostic accuracy of sinus venous ASD,[9] and it has also been shown to be superior to TTE in this regard[10] with a novel analysis of atrial defects and dysfunction.[11]

In our case, there is a rare association of PLSVC and ASD; this case also presents a right side volume overload due to high flow FAV and ASD.

CONCLUSIONS

A careful echocardiographic examination is required when there is an association between PLSVC and other cardiac abnormalities such as an ASD when CS is extremely dilated, and it is coexisting with enlargement of right ventricle. In our case, the diagnosis of PLSVC was suspected on routine TTE, and a definitive diagnosis of PLSVC was made on CT pulmonary angiography because the saline contrast echocardiography was not performed for why there is a high-flow AVF on the left forearm for hemodialysis, which contributes to right side volume overload.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.