Isolated Pulmonary Regurgitation without Right Heart Remodeling or Pulmonary Hypertension

Introduction

Pulmonary regurgitation (PR) is commonly secondary to pulmonary hypertension, congenital heart disease (eg, repaired tetralogy of Fallot), endocarditis, or carcinoid syndrome, often leading to right ventricular (RV) dilation and heart failure [1]. Moderate to severe PR is typically due to pulmonary hypertension (77%), congenital/iatrogenic causes (11%), primary pulmonary valve disease (2%, with 88% due to carcinoid), or isolated idiopathic causes (10%), while severe PR is attributed to congenital/iatrogenic disease (52%), pulmonary hypertension (39%), primary PR (5%), or isolated idiopathic PR (3%) [5]. Mild PR is often benign in healthy individuals, but moderate PR can cause RV volume overload if progressive [2]. Potential causes include idiopathic pulmonary artery dilatation, valvular degeneration, or intermittent hemodynamic stress from arrhythmias [3]. The distinction between mild and moderate PR lies in the regurgitant volume and its hemodynamic impact; mild PR typically has minimal clinical consequences, whereas moderate PR can lead to RV volume overload over time, necessitating closer monitoring [2,4]. This case report is noteworthy because it presents a rare instance of isolated moderate PR without associated conditions, offering insights into diagnostic challenges and the need for long-term surveillance. The purpose of this report is to describe the clinical presentation, diagnostic evaluation, and management strategy of isolated moderate PR, emphasizing the role of advanced imaging and the potential implications for clinical practice, including the need for further research into its natural history and optimal management. This case of isolated moderate PR in a patient with normal RV function and no pulmonary hypertension emphasizes the need for detailed echocardiographic assessment and long-term monitoring to detect progression, with emerging roles for advanced imaging like cardiac MRI [3].

Case Report

DIFFERENTIAL DIAGNOSIS:

The differential diagnosis for moderate PR without right heart remodeling was carefully considered. Primary valvular degeneration, suspected to be myxomatous or age-related based on indirect evidence from similar changes in the mitral valve, was considered the most probable etiology, given the patient’s age and echocardiographic findings of mitral valve involvement [2]. Long-standing pSVT may have contributed to intermittent RV pressure overload, potentially causing valvular dysfunction [3]. Idiopathic pulmonary artery dilatation was ruled out due to the normal pulmonary artery diameter (22 mm) [3]. Endocarditis was unlikely, as there were no systemic signs of infection or vegetations on echocardiography, despite the patient’s immunocompromised state from multiple myeloma. Connective tissue disorders, such as Marfan or Ehlers-Danlos syndromes, were excluded due to the absence of systemic features, including normal aortic root dimensions (3.2 cm) and no joint hypermobility or skin findings [3].

TREATMENT:

Given the patient’s hemodynamic stability and absence of symptoms during hospitalization, no immediate intervention was required for PR. Management focused on conservative monitoring, as normal RV size and RVSP (22.89 mmHg) did not indicate urgent intervention [5]. The patient’s pSVT was well-controlled with existing anti-arrhythmic medications, requiring no adjustments. Hypertension was optimized with the current therapy. Consideration of cardiac MRI was discussed to provide precise RV volume assessment, including right ventricular end-diastolic and end-systolic volumes, if PR progresses, as it offers superior quantification of ventricular dimensions and function compared to echocardiography, particularly in detecting subtle changes in RV volume overload [3,6]. Cardiac MRI was not performed at the time due to the patient’s clinical stability, absence of current indications for advanced imaging, and a shared decision with the patient prioritizing non-invasive monitoring initially.

OUTCOME AND FOLLOW-UP:

The patient was discharged without signs of right heart failure. A structured follow-up plan included serial echocardiography every 6 months to assess PR progression and RV function, alongside cardiology follow-up for pSVT surveillance. The patient was educated on reporting symptoms such as dyspnea or peripheral edema, which could indicate worsening PR or RV dysfunction. If RV dilation or symptomatic PR develops, pulmonary valve replacement may be considered, guided by ESC guidelines, which recommend intervention for RV end-diastolic volume >150 mL/m2 or symptomatic deterioration [5].

Discussion

Isolated moderate PR without right heart remodeling is rare, typically seen in secondary conditions like pulmonary hypertension or congenital defects [2]. This case is notable for its primary presentation, suspected to be due to valvular degeneration or pSVT-related strain, as no other structural abnormalities were identified on echocardiography (Figures 1–5). The absence of RV remodeling, with normal RV size (<5 mm wall thickness) and RVSP (22.89 mmHg), supported a conservative management strategy, as there was no evidence of volume overload or hemodynamic compromise [5]. Pellikka et al (1993) described PR in carcinoid syndrome, but their patient lacked systemic features [1].

The diagnostic reasoning for conservative management was based on the absence of RV dilation, normal RV function, and low RVSP (22.89 mmHg), indicating minimal hemodynamic impact [4,5]. Potential etiologies include suspected myxomatous degeneration, inferred from similar findings in the mitral valve but without direct assessment of the pulmonary valve, or intermittent RV strain from pSVT, which can cause transient pressure overload [3,6]. The long-term implications of isolated PR are not well-established, but studies suggest that progressive PR can lead to RV volume overload and dysfunction over time [2,6]. A recent study by Naser et al (2025) reported that isolated idiopathic moderate-to-severe PR occurs in 10% of cases, while isolated idiopathic severe PR occurs in 3%, with most patients remaining stable but requiring monitoring for progression [4]. The porcine model by Kopic et al (2017) demonstrated that PR reduces RV longitudinal function, which may precede overt remodeling, supporting the need for vigilant follow-up in this case [6]. Cardiac MRI, offering superior RV assessment, may be considered for precise follow-up, especially if echocardiography is inconclusive [3]. Criteria for intervention, such as RV dilation or symptomatic PR, align with ESC guidelines for valvular heart disease [5]. These guidelines recommend pulmonary valve replacement for RV end-diastolic volume >150 mL/m2, RV systolic dysfunction, or symptoms like dyspnea or reduced exercise capacity [5]. Routine echocardiographic surveillance remains critical to detect progression, with cardiac MRI as a potential adjunct for accurate RV volume assessment [3,6]. This case highlights the need for further research into the natural history of isolated PR and optimal management strategies, as current evidence is limited [4,6].

Conclusions

This case highlights the diagnostic and management challenges of isolated moderate PR. Advanced imaging (eg, echocardiography and potentially cardiac MRI) and symptom-guided follow-up are essential to monitor progression, with potential interventions like pulmonary valve replacement if RV dysfunction or symptoms (eg, dyspnea, peripheral edema) emerge. Clinical signs warranting treatment escalation include RV end-diastolic volume >150 mL/m2, RV systolic dysfunction, or symptomatic deterioration, as per ESC guidelines [5]. Clinicians should prioritize valvular degeneration and arrhythmia-related strain in the differential diagnosis, ensuring long-term surveillance to prevent complications. This case report contributes to the limited literature on isolated PR and underscores the need for further studies to define its natural history and optimal management [4,6].