Abstract
Background
Patent ductus arteriosus (PDA) is one of the most common cardiac abnormalities in children, but in rare cases it can go undiagnosed into adulthood until symptoms arise.
Case Summary
We present a unique case of a 55-year-old male patient with severe pulmonary hypertension and polycythemia vera requiring frequent phlebotomy who was found to have a PDA on cardiac computed tomography. Owing to the severity of his pulmonary hypertension, he was not a candidate for closure and was therefore treated with medical management.
Discussion
PDA diagnosed in adulthood is rare and carries significant morbidity, with findings such as congestive heart failure, infectious endarteritis, or severe pulmonary hypertension. Our patient had multiple severe and rare sequelae of a very large unrepaired PDA, including Eisenmenger syndrome and polycythemia vera, that required frequent phlebotomy. Despite the large size of the PDA, it was not visualized on echocardiography.
Key words: congenital heart disease, CT, patent ductus arteriosus, pulmonary hypertension
Graphical Abstract
History of Presentation
A 55-year-old man was referred to our hospital for further evaluation of chronic pulmonary hypertension. On presentation to our clinic, his blood pressure was normal, and he had mild desaturations on room air, with oxygen saturation of 93% on pulse oximetry. Cardiac auscultation revealed normal first heart sound and accentuated second heart sound. There was no audible murmur. No gallops, thrills, heaves, or rubs were noted. No digital clubbing was present, but he did have notable central cyanosis.
Past Medical History
The patient was a product of full-term delivery and had a complicated hospital course owing to neonatal cytomegalovirus infection and resultant right eye blindness and hearing impairment, with subsequent left cochlear implant and residual hearing difficulty. His mother reported a history of murmur in early childhood. However, she was reassured at the time and lost follow-up with cardiology for many years. He was, however, evaluated with echocardiograms on at least 2 occasions before presentation to our clinic; both showed no evidence of shunting lesions. His medical history was also remarkable for severe pulmonary hypertension, chronic respiratory failure, nocturnal hypoxemia for which he was on 5 L of oxygen supplementation at night, and polycythemia requiring frequent encounters for phlebotomy. He was not very physically active. He was assessed as being NYHA functional class II-III for several years without angina.
Differential Diagnosis
The differential diagnosis for the etiology of this patient's pulmonary hypertension was broad and included unrepaired cardiac shunting lesion, left heart disease, interstitial lung disease, hypoventilation disorders such as obstructive sleep apnea, chronic thromboembolism, and myeloproliferative disorder such as his known polycythemia vera.
Investigations
His electrocardiogram showed normal sinus rhythm and right ventricular hypotrophy. The echocardiogram was limited because of poor acoustic windows. Right ventricular hypertrophy and severe systolic dysfunction were noted. The left ventricle was normal in size with mildly diminished systolic function. There was mild tricuspid valve regurgitation. The estimated right ventricular systolic pressure was 93 mm Hg. No intracardiac shunts were identified. Magnetic resonance imaging was contraindicated owing to his cochlear implant, so contrast-enhanced functional cardiac computed tomography (CT) was performed, which demonstrated a large patent ductus arteriosus (PDA) (16 × 13 mm) with bidirectional shunting (Figure 1, Figure 2, Figure 3). Dilation of the main pulmonary artery and distal pulmonary arteries was also noted, consistent with pulmonary hypertension (Figure 4). He was referred for diagnostic hemodynamic cardiac catheterization and treatment of his PDA on the assumption that it had contributed to the development of pulmonary hypertension. Diagnostic catheterization was performed 3 months later and showed a Qp/Qs ratio of 0.9, mean pulmonary artery pressure of 83 mm Hg, and pulmonary vascular resistance of 23.7 WU.
Figure 1.
PDA Axial-View
Axial-view computed tomography scan showing large PDA. AAo = ascending aorta; DAo = descending aorta; PA = pulmonary artery; PDA = patent ductus arteriosus.
Figure 2.
PDA Sagittal-View
Sagittal-view computed tomography scan showing large PDA. AA = aortic arch; AAo = ascending aorta; DAo = descending aorta; PA = pulmonary artery; PDA = patent ductus arteriosus.
Figure 3.
PDA and Main PA Sagittal-View
Sagittal-view computed tomography scan showing large PDA and dilated main pulmonary artery. AA = aortic arch; PA = pulmonary artery; PDA = patent ductus arteriosus.
Figure 4.
Pulmonary Arteries Axial-View
Axial-view computed tomography scan showing dilated pulmonary trunk and pulmonary arteries. LPA = left pulmonary artery; MPA = main pulmonary artery; RPA = right pulmonary artery.
Management
Given his significantly elevated pulmonary vascular resistance and net right-to-left shunting (Eisenmenger physiology), the duct was not closed, as it would have put him at high risk of low cardiac output, progressive right heart failure, and potential for syncope or sudden cardiac death. The patient was subsequently admitted to the adult heart failure intensive care unit for initiation of medical management. He was started on intravenous epoprostenol, then was switched to treprostinil before being discharged owing to insurance coverage.
Follow-Up
At his 9-month follow-up visit, he had significant improvement in his oxygen saturation levels as well as his functional status.
Discussion
The diagnosis of PDA in adult patients is uncommon, as most cases are discovered and treated in childhood. Detection requires a high degree of clinical suspicion, particularly given the varied symptomatology. The delay in diagnosis in this case was multifactorial, with contributing factors that included lack of follow-up from childhood by a pediatric cardiologist, inability to visualize the defect with echocardiogram on multiple occasions, and low suspicion for a congenital heart defect in an adult as the cause of the symptoms.
The mortality of untreated large PDA in adults is estimated to be 1.8% per year, and few affected patients survive beyond 50 years of age without intervention.1 Pulmonary hypertension is a common presenting complication, however only 1 previous case has been reported; this involved a patient who presented with polycythemia that required phlebotomy before discovery of a PDA.2
Echocardiography has long been the preferred initial imaging modality for suspected cardiac lesions owing to its relative ease of use, noninvasiveness, and cost-effectiveness. It is useful in establishing the diagnosis of PDA as well as determining its morphology and flow velocity. It is also useful for assessing the effect of PDA on hemodynamics by estimating pulmonary artery diastolic pressure as well as left and right ventricular size and function.3 However, echocardiographic evaluation is user dependent, and it can be limited in adults given poor acoustic windows. Therefore, supplemental advanced imaging modalities may be required to establish the diagnosis. Our patient had multiple echocardiograms that did not show evidence of PDA despite its large size, owing to suboptimal images secondary to poor acoustic windows.
Over the past decade, cardiac CT is increasingly being used as a noninvasive alternative for evaluation in patients with adult congenital heart disease. In comparison to echocardiography, CT has high three-dimensional spatial resolution, which is an excellent tool for imaging small vessels and extracardiac anatomy. The high resolution allows for better, more detailed evaluation of structures not optimally visualized on echocardiogram. CT is also beneficial in preprocedural planning of percutaneous PDA device closure.4 In addition, it is useful in assessing lung parenchyma. Despite the wide availability of CT and rapid acquisition, the concern of radiation exposure makes it an unattractive imaging modality for serial follow-up. However, according to the PROTECTION VI study, the median estimated radiation dose from cardiac CT decreased by 78% from 2007 to 2017 with the development of methods for radiation dose reduction.5
Conclusions
Untreated large PDA can lead to significant morbidity and mortality. It requires a high level of clinical suspicion and possible evaluation with advanced imaging to establish the diagnosis and to aid in potential preprocedural planning. Contrast-enhancing CT is an excellent tool when magnetic resonance imaging is contraindicated.
Funding Support and Author Disclosures
The authors have reported that they have no relationships relevant to the contents of this paper to disclose.
Take-Home Messages
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This case highlights the importance of advanced imaging modalities in diagnosing patent ductus arteriosus in adults, given the diagnostic limitations of echocardiography.
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Consideration should be made to the presence of a right-to-left shunting cardiac lesion in adult patients with refractory or otherwise unexplained pulmonary hypertension.
Footnotes
The authors attest they are in compliance with human studies committees and animal welfare regulations of the authors’ institutions and Food and Drug Administration guidelines, including patient consent where appropriate. For more information, visit the Author Center.
References
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