Common femoral vein Doppler as an adjunct for serial assessment of right ventricular dysfunction after lung transplantation

Abstract

Right ventricular dysfunction complicates the early course after lung transplantation, particularly when primary graft dysfunction elevates pulmonary vascular resistance. Bedside assessment is challenging: transthoracic echocardiographic windows are often limited after clamshell thoracotomy, and pulmonary artery catheters are typically removed within days. Common femoral vein (CFV) Doppler offers a noninvasive, position-independent means of detecting venous congestion via peripheral venous waveform pulsatility. We describe a bedside protocol integrating serial CFV Doppler with echocardiography and invasive hemodynamics for postoperative right ventricular assessment, illustrated in a 77-year-old lung transplant recipient with pre-existing right ventricular dysfunction and primary graft dysfunction requiring venovenous extracorporeal membrane oxygenation (ECMO). Markedly abnormal bidirectional CFV Doppler waveforms were concordant with invasive evidence of venous congestion and progressively normalized in parallel with hemodynamic recovery, ECMO decannulation, and clinical improvement. CFV Doppler may serve as a practical adjunct for serial bedside assessment of right-sided hemodynamics after lung transplantation.

Right ventricular (RV) dysfunction is a consequential complication following lung transplantation. Primary graft dysfunction (PGD), complicating 12–55% of cases, acutely elevates pulmonary vascular resistance and imposes poorly tolerated afterload on the right ventricle.1, 2 Bedside RV assessment in this setting is challenging. Transthoracic echocardiographic windows are frequently compromised after clamshell thoracotomy³ and while pulmonary artery catheters provide continuous hemodynamic data in the immediate postoperative period, they are typically removed within days, leaving a monitoring gap during ongoing recovery. Venous Doppler frameworks such as Venous Excess Ultrasound Score (VExUS) have advanced congestion assessment.⁴ Beyond variable image quality, reliable interrogation of the portal, hepatic, and renal veins requires dedicated training in vessel-specific acquisition and waveform interpretation.

The common femoral vein (CFV) offers an alternative acoustic window. Given its anatomical continuity with the inferior vena cava and right atrium, elevated right atrial pressure propagates cardiac pulsatility distally, producing increasingly abnormal Doppler waveforms detectable at the groin.5, 6 Although portal vein pulsatility and other abdominal venous metrics are validated in cardiac surgery and critical care, CFV Doppler uses an acquisition technique familiar to any intensivist trained in femoral venous access. A recent scoping review of 19 studies identified no evaluation of CFV Doppler after lung transplantation.⁷

We developed a bedside protocol integrating CFV Doppler with transthoracic echocardiography, pulmonary artery catheter data, and clinical markers of perfusion (Figure 1). CFV Doppler is performed using a high-frequency linear transducer placed over the common femoral vein, with pulsed-wave interrogation and emphasis on the peak retrograde velocity to peak antegrade velocity (PRV/PAV) ratio to minimize angle dependency. Abnormal waveforms, defined as PRV ≥10 cm/s or PRV/PAV >50% based on previously described thresholds from cardiac surgery and general ICU populations,5, 6 not yet validated in lung transplant recipients, prompt reassessment focused on RV optimization. The specific balance among preload reduction, afterload reduction, and inotropic support is determined by the accompanying echocardiographic and hemodynamic profile rather than the Doppler pattern alone. Normal waveforms in hemodynamically unstable patients suggest hypovolemia or distributive physiology, directing cautious volume administration and vasopressor optimization. Serial assessments are performed at 4-hour intervals for the first 8 h, then every 24 h through postoperative day 3.

Figure 1.

CFV Doppler-Guided Management Protocol for RV Dysfunction After Lung Transplantation. Protocol flowchart illustrating the integrated bedside assessment algorithm for suspected right ventricular dysfunction in the early postoperative period following bilateral lung transplantation.

A 77-year-old woman with radiation-induced pulmonary fibrosis, pulmonary hypertension (estimated right ventricular systolic pressure 55–60 mmHg) and pre-existing RV dysfunction (tricuspid annular plane systolic excursion 1.0 cm; reference >1.7 cm⁸) underwent bilateral lung transplantation via clamshell thoracotomy (Supplemental Figures 1 and 2). Bilateral lung transplantation was performed with central venoarterial ECMO support. Once transplantation was completed and hemodynamic stability achieved with vasoactive support, the patient was reconfigured to peripheral VV-ECMO for concern for severe PGD (grade 3).¹

On postoperative day (POD) 0, the protocol was activated based on hemodynamic instability, radiographic concern for PGD, and elevated RV afterload. The hemodynamic trajectory and serial Doppler evolution are presented in Figure 2, Figure 3. CFV Doppler, performed contralateral to the ECMO drainage cannula, demonstrated markedly abnormal bidirectional waveforms with PRV/PAV >50%, concordant with invasive findings of venous congestion (central venous pressure (CVP) 8→18 mmHg, pulmonary artery pressure (PAP) up to 42/16 mmHg, cardiac index 2.0–2.2 L/min/m² 4 h postoperatively). These findings were consistent with and supportive of the integrated clinical assessment directing management toward RV optimization: preload reduction with intermittent furosemide, continuation of inhaled epoprostenol for afterload reduction, and escalation of inotropic support with dobutamine and milrinone. Systemic perfusion was supported with vasopressors and inotropes; the aggregate vasoactive-inotropic score (VIS) peaked at approximately 38 on POD 2.

Figure 2.

Hemodynamic and CFV Doppler Trajectory with Targeted Interventions. Postoperative course following bilateral lung transplantation showing serial CFV Doppler findings, central venous pressure, pulmonary artery pressure, cardiac index, and concurrent interventions from POD 0 through POD 3. CFV, common femoral vein; CI, cardiac index; CVP, central venous pressure; ECMO, extracorporeal membrane oxygenation; PAP, pulmonary artery pressure; POD, postoperative day; PRV, peak retrograde velocity; PAV, peak antegrade velocity.

Figure 3.

Serial Common Femoral Vein Pulsed-Wave Doppler Waveforms. Serial pulsed-wave Doppler waveforms of the left common femoral vein obtained at six time points following bilateral lung transplantation demonstrating evolution from bidirectional to continuous antegrade flow with clinical recovery. (A) Immediate postoperative (POD 0): markedly abnormal bidirectional waveform with PRV/PAV ratio >50%. (B–C) POD 0 at 4 and 8 h: bidirectional waveform that improved with therapeutic intervention. (D) POD 1: improving pulsatility. (E) POD 2: antegrade flow with reduced pulsatility. (F) POD 3: predominantly continuous antegrade flow consistent with normalization of venous congestion. PAV, peak antegrade velocity; POD, postoperative day; PRV, peak retrograde velocity; VV-ECMO, venovenous extracorporeal membrane oxygenation.

By POD 1, CFV Doppler showed resolution of retrograde pulsatility, paralleling improved invasive hemodynamics (CVP 14 mmHg, PAP 32/14 mmHg, cardiac index 2.4 L/min/m²). By POD 2, waveforms demonstrated predominantly antegrade flow with reduced pulsatility (CVP 9–10 mmHg, PAP 22/11 mmHg, cardiac index 2.5 L/min/m²). VV-ECMO was decannulated on POD 2. By POD 3, continuous antegrade flow had normalized (CVP 7–8 mmHg, PAP 19/10 mmHg, cardiac index 2.4 L/min/m²). Vasoactive support was fully withdrawn by POD 5, and the patient was discharged after 15 days without supplemental oxygen.

The concordance between serial CFV Doppler waveform morphology and invasive hemodynamic trajectory in this case supports the potential utility of this technique as an adjunct bedside tool. Several confounders warrant consideration. VV-ECMO drainage generates continuous, non-pulsatile flow that theoretically cannot produce the cardiorespiratory-synchronized bidirectional pulsatility observed; active drainage would bias toward falsely normal waveforms, suggesting the markedly abnormal POD 0 findings potentially underestimated congestion severity. Positive-pressure ventilation and positive end-expiratory pressure (PEEP) influence venous return and may affect waveform morphology; serial measurements in this case were obtained under consistent ventilator settings (PEEP 10 cmH₂O throughout). Future protocols should document ventilatory parameters alongside Doppler assessments. Prior work in pulmonary hypertension has demonstrated that CFV Doppler detects elevated right atrial pressure with reasonable diagnostic performance against invasive reference,⁹ supporting application in lung transplant recipients with antecedent pulmonary vascular disease.

This report has important limitations. It reflects a single-patient experience and cannot establish diagnostic accuracy or generalizability. Multiple concurrent interventions preclude attribution of outcome to any single monitoring modality. We emphasize that CFV Doppler informed but did not independently drive management decisions. Pre-transplant CFV Doppler was not obtained and the quantitative thresholds applied were derived from non-transplant populations. Sex-specific effects on CFV waveform morphology cannot be assessed from a single case. CFV waveform interpretation is operator-dependent.

CFV Doppler may represent a practical, reproducible adjunct for serial bedside assessment of right-sided hemodynamics after lung transplantation, complementing invasive monitoring and echocardiography when acoustic windows are limited. Prospective validation correlating CFV Doppler with invasive hemodynamics across diverse lung transplant recipients is needed.¹⁰

Ethics approval

All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional research committee and with the 1964 Declaration of Helsinki and its later amendments.

Data Availability

All data supporting the findings of this report are contained within the manuscript and its supplemental materials. No additional datasets were generated or analyzed during the preparation of this work. Further details regarding the case described are not publicly available in order to protect patient privacy but may be made available from the corresponding author on reasonable request, subject to institutional review board approval and applicable privacy regulations.

Consent for publication

Written informed consent was obtained from the patient (or the patient's legally authorized representative) for publication of this case report and any accompanying images.

Compliance with the Declaration of Istanbul

The authors declare that the donor organ used in the case described was procured in accordance with the WHO Guiding Principles on Human Cell, Tissue and Organ Transplantation and the Declaration of Istanbul. No organs or tissues were obtained from executed prisoners or prisoners of conscience.

Funding

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

CRediT authorship contribution statement

Sajid Kadir: Conceptualization, Methodology, Investigation, Writing – original draft, Writing – review and editing, Visualization, Project administration. Mauricio Tellez: Investigation, Data curation, Writing – review and editing. Travis Murphy: Writing – review and editing. Andres Pelaez: Conceptualization, Supervision, Writing – review and editing. All authors read and approved the final manuscript.

Declaration of Generative AI and AI-Assisted Technologies in the Writing Process

During the preparation of this work, the authors used Claude (Anthropic) for language editing, cross-checking of numerical and tabular consistency, reference formatting, and figure code generation. After using these tools, the authocrs reviewed and edited the content as needed and take full responsibility for the content of the publication.

Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Appendix A. Supplemental material

Supplemental Figure 1. Pre-transplant Imaging Demonstrating Radiation-Associated Pulmonary Fibrosis. (A) Pre-transplant chest radiograph demonstrates diffuse bilateral reticular and coarse interstitial opacities with architectural distortion. (B) Axial high-resolution computed tomography demonstrates advanced fibrotic interstitial lung disease with honeycombing, traction bronchiectasis, and architectural distortion

Supplemental Figure 2. Serial Postoperative Chest Radiographs Following Bilateral Lung Transplantation. Serial anteroposterior chest radiographs obtained at postoperative days 0 through 3 demonstrating progressive radiographic improvement paralleling clinical recovery