Silent patent ductus arteriosus incidentally found before balloon mitral valvotomy for severe rheumatic mitral stenosis

Abstract

Rheumatic heart disease (RHD) and congenital heart disease (CHD) rarely co-exist in the same patient. However, such associations are not unknown in areas where RHD is endemic. We report a rare combination of severe rheumatic mitral stenosis, severe pulmonary artery hypertension (PAH), and an incidental clinically silent patent ductus arteriosus (PDA). The patient was initially subjected to a balloon mitral valvotomy to assess if the resultant fall in PA pressure would alter the flow dynamics of the PDA. Since the ductal flow remained small and clinically inaudible, no further intervention was advised. The case highlights the importance of detailed echocardiographic examination in patients with RHD to detect co-existent CHD and logical decision making in their management.

<Learning objective: A detailed echocardiographic examination is needed in all cases even when a diagnosis is apparent. Despite obvious rheumatic mitral stenosis, meticulous echocardiography revealed a small PDA, which was clinically silent. Since severe PAH can alter findings of PDA, we first performed balloon mitral valvotomy to see if resultant fall in PA pressure would alter the flow dynamics of PDA. Despite fall in PA pressures, the PDA flow remained trivial and it was clinically inaudible. Hence, no further intervention was advised.>

Introduction

The occurrence of rheumatic heart disease (RHD) with congenital heart disease (CHD) in the same patient is a rare entity. Among shunt lesions, atrial septal defects (ASD) are more commonly associated with RHD, while post-tricuspid shunts such as patent ductus arteriosus (PDA) and ventricular septal defects (VSD) are relatively uncommon. Previous associations of rheumatic mitral stenosis (MS) with PDA have invariably been in the setting of a large defect with anecdotal reports of surgical closure of the PDA being reported [1], [2], [3]. The physiologic and clinical consequences of such an association are essentially governed by the underlying pulmonary vascular resistance which chiefly depends on the size of the PDA and severity of MS.

We report a hitherto unreported combination of severe rheumatic MS, severe pulmonary artery hypertension (PAH), and an incidental clinically silent PDA. The patient was initially subjected to a balloon mitral valvotomy (BMV) to assess if the resultant fall in pulmonary artery (PA) pressure would alter the flow dynamics of the PDA. Since the ductal flow remained small and clinically inaudible, no further intervention was advised.

Case report

The patient was a 32-year-old male with shortness of breath New York Heart Association (NYHA) symptom class II for the previous 6 years which had gradually increased to class III for the past 2 months. At presentation, the patient had sinus tachycardia (heart rate 100 bpm), tachypnea (respiratory rate 22/min), and his blood pressure was 110/74 mmHg. Clinical examination revealed a loud first heart sound, an apical long, mid diastolic murmur with presystolic accentuation, and signs of severe PAH, all suggesting severe MS. A 12-lead electrocardiogram showed sinus tachycardia, right axis deviation, and bi-atrial enlargement (Fig. 1a). Chest X-ray revealed cardiomegaly, enlargement of the left and right atrium, and evidence of severe PAH (Fig. 1b). Transthoracic echocardiography (TTE) confirmed severe rheumatic MS (trans-mitral peak and mean gradient of 25 and 13 mmHg, respectively), mitral valve orifice area of 0.9 cm² (Fig. 2a), moderate tricuspid regurgitation, and severe PAH (predicted right ventricular systolic pressure of 74 mmHg). In addition, a small (2 mm) PDA with left-to-right shunt was also visualized (Fig. 2b). The continuous wave Doppler gradient across the PDA revealed a peak gradient (PG of ∼36 mmHg, Fig. 2c), corresponding to predicted PA pressure of ∼74 mmHg since the measured systolic blood pressure was 110 mmHg. The mitral valve appeared suitable for BMV with a Wilkins score of 5/16.

Fig. 1.

12-Lead electrocardiogram (a) showing sinus tachycardia, right axis deviation, and bi-atrial enlargement; X-ray chest (b) depicting cardiomegaly, enlargement of the left and right atrium, and evidence of severe pulmonary artery hypertension.

Fig. 2.

Pre balloon mitral valvotomy (BMV) 2D echocardiography showing severe mitral stenosis (parasternal short-axis view, a) and a small patent ductus arteriosus (PDA) (2D and Doppler, b, c); Post BMV 2D echocardiography showing adequately open mitral valve (parasternal short-axis view), (d) and the tiny PDA (2D and Doppler, e, f). Ao, aorta; MPA, main pulmonary artery; PDA, patent ductus arteriosus; DA, descending aorta.

Since the PDA still demonstrated left-to-right flow (although it was clinically inaudible), we planned to first perform BMV and reassess the PDA for likely device closure, once the PA pressures had reduced following BMV. After obtaining informed consent, the patient underwent left and right heart cardiac catheterization which confirmed severe MS (trans-mitral end diastolic gradient 10 mmHg) and severe PAH [right ventricular (RV) systolic pressure 75 mmHg, PA mean pressure 48 mmHg, aortic systolic pressure 110 mmHg, Table 1]. An aortogram revealed a tiny PDA (2 mm) while the oximetry data showed only a small left-to-right shunt (Qp/Qs ratio of 1.2:1) (Video 1, Table 1).

Table 1.

Parameters before and after BMV.

Chamber	Pre BMV (HR 78/min)		Post BMV (HR 80/min)
	Pressure (mmHg)	Oxygen saturations	Pressure (mmHg)	Oxygen saturations
HSVC		64		66
LSVC		65		65
IVC		69		70
RA (a/v/m)	8, 2, 4	69	7, 2, 4	69
RV	75/0, 6	70	55/0, 6	71
PA	75/31 (48)	77	55/28 (38)	78
PCWP	24, 31, 26	99.9	16, 18, 14	99.6
LA (a/v/m)	23, 30, 27	99.6	13, 15, 14	99.3
LV	110/0, 6	98.7	108/0, 5	98.8
Aorta	110/57 (75)	97.6	110/58 (76)	96.6
MV (PG/MG/EDG)	18, 13, 10		10, 4, 2
CO (L/min/m2)	3.78		4.78
MVA (cm2)	0.9		1.6
SVR	12.84		11.84
PVR	4.93		4.23
Qp/Qs	1.2		1.21

BMV, balloon mitral valvotomy; HR: heart rate; HSVC, high superior vena cava; LSVC, left superior vena cava; IVC, inferior vena cava; RA, right atrium; RV, right ventricle; PA, pulmonary artery; PCWP, pulmonary capillary wedge pressure; LA, left atrium; LV, left ventricle; MV (PG/MG/EDG), mitral valve: peak gradient, mean gradient, end-diastolic gradient; CO, cardiac output; MVA, mitral valve area; SVR, systemic vascular resistance; PVR, pulmonary vascular resistance.

BMV was performed using the Inoue balloon (Toray, Tokyo, Japan) (24 × 1, single inflation) with a satisfactory result. The mitral valve area increased to 1.6 cm² while the RV systolic pressure decreased from 75 mmHg to 55 mmHg. Repeat oximetry revealed no change in the left-to-right shunt or Qp/Qs (Table 1). A repeat aortogram to look for any change in the PDA flow (after the fall in PA pressure) revealed no significant change in the PDA flow (either on angiography or by oximetry, Video 2, Table 1) and it remained clinically inaudible. Therefore, no further immediate intervention for the PDA was done.

An echocardiographic assessment 1 month later reconfirmed the fact that mitral valve area was 1.5 cm² (Fig. 2d), the RV systolic pressure was 50 mmHg, and the PDA flow remained small with slight reduction in color Doppler flow (smaller acceleration and less mosaic signal, Fig. 2e). The continuous wave Doppler gradient across the PDA now revealed a PG of 62 mm corresponding to predicted PA pressure of ∼50 mmHg as the measured systolic blood pressure was 112 mmHg (Fig. 2f). Since there was no change in the PDA flow dynamics even after 1 month and the PDA was clinically silent, the patient was advised medical follow-up.

Discussion

The prevalence of RHD in school going children in India is estimated to be in the range of 2–11 per 1000, while that of CHD is ∼8 per 1000 live births [4], [5]. Therefore, the co-existence of both conditions is considered to be uncommon. In a retrospective analysis of 285 patients at a tertiary referral center, Bokhandi et al. reported that only 1.8% patients had both RHD and CHD; the observed congenital lesions included subaortic membrane, large ventricular septal defect (VSD), coarctation, and atrial septal defect (ASD) [6]. In a necropsy study of 2756 patients who died because of RHD, Zabal et al. reported that 14.6% had an association with CHD, of which aortic (39.6%) and pulmonary (27.7%) involvement were most frequent, while ASD, PDA, and VSD were present in 4.9%, 2.9%, and 1%, respectively [7]. In a study of 15,080 school going children aged 5–16 years in Northern India, Thakur et al. reported that the prevalence of rheumatic fever (RF)/RHD was significantly higher in children with CHD (8.8%) as compared to those without CHD (0.3%) [8]. The authors proposed that the presence of CHD may actually predispose the child to the occurrence of RF/RHD. Whether the occurrence of CHD and RHD in the same patient is a coincidence or the presence of CHD in a patient actually predisposes to RF and future likelihood of RHD remains speculative.

The association of rheumatic MS with a small, clinically silent PDA as reported in our case is hitherto unreported. In all previously reported associations with rheumatic MS, the PDA was large with either combined aortic and mitral valve disease or isolated MS [1], [2]. The physiologic consequences and clinical presentation of PDA co-existing with rheumatic MS depend chiefly on the size of the PDA, the functional capability of the volume-loaded left ventricle and the underlying pulmonary vascular resistance. In patients with an isolated large PDA, the increased pulmonary blood flow can itself produce an apical mid-diastolic murmur across the mitral valve, even in the absence of significant MS. In patients with large PDA and MS, the lungs are exposed not only to the back pressure of pulmonary venous hypertension due to MS, but also to the increased pulmonary blood flow due to the left-to-right shunt. The larger amount of blood having to pass through the narrowed mitral valve accentuates the effect of the stenosis.

On the other hand, if the underlying MS leads to severe PAH, the shunt through the PDA may become reduced or even reversed, obscuring the clinical signs of the left-to-right shunt. In such cases, it would be worthwhile to reassess the PDA flow after reduction in PA pressure (i.e. following a BMV). Patra et al. reported a case with rheumatic MS, large PDA, multiple VSDs, and Eisenmneger's syndrome in which the authors contemplated performing a BMV to decrease PA pressure and thus the right to left shunt [3]. However, the procedure could not be performed due to lack of consent by the patient.

In view of the severe PAH present in our case, we planned a BMV with reassessment of PDA flow after the resultant fall in PA pressure following the BMV. After performance of a successful BMV in our case, expectedly there was a significant decrease in mean PA systolic and mean pressure, pulmonary capillary wedge pressure, trans-mitral gradients, and an increase in the mitral valve area. However, a repeat aortogram performed immediately following the BMV failed to reveal any significant change in the ductal flow, either by angiography or on oximetry. Hence, no further intervention for the PDA was done.

Although endarteritis of clinically silent PDA has been reported, the overall risk is low [9]. According to current guidelines, clinically silent PDAs do not merit closure [10]. Therefore, after performing BMV, the patient was advised medical follow-up.

We conclude that the association of RHD with PDA is rare. The clinical and physiological consequences of such combinations chiefly depend on the underlying pulmonary vascular resistance. Careful hemodynamic assessment with individualized management of each case is essential, as highlighted in our case.

Conflicts of interest

There are no conflicts of interest to declare.

Appendix A. Supplementary data

The following are Supplementary data to this article: