Episode Summary: The Fellow on Call – Episode 131: VTE Series – Approach to Workup and Initial Management
In Episode 131 of The Fellow on Call: The Heme/Onc Podcast, hosted by Rouleaux University Medical Center, Ronak, Vivek, and Dan delve into the intricate world of Venous Thromboembolism (VTE). This episode marks the commencement of a highly anticipated series focused on the fundamentals, core concepts, and management strategies in hematology and oncology, particularly centered around VTE.
Introduction to the VTE Series
The hosts kick off the episode by acknowledging their brief hiatus, emphasizing the importance of self-care in the demanding field of medicine. They express enthusiasm about returning with content that addresses common questions and challenges related to anticoagulation management post-clot formation.
Case Study Presentation
Dan introduces a clinical scenario to contextualize their discussion:
A 58-year-old male with a history of hypertension, hyperlipidemia, type 2 diabetes, and metastatic pancreatic cancer presents to the emergency room with acute shortness of breath and lower extremity swelling. Vital signs reveal a heart rate of 110 bpm and an oxygen saturation of 86% on room air.
Notable Quote:
Dan [04:24]: "This is certainly very worrisome for something like a pulmonary embolism, which fits into the larger category of venous thromboembolism or VTE."
Categorizing Pulmonary Embolism Severity
The team delineates the severity of pulmonary embolism (PE) into three categories:
- Massive PE: Characterized by hemodynamic instability requiring immediate intervention.
- Submassive PE: Exhibits signs of right heart strain without hemodynamic compromise, potentially necessitating interventions like thrombectomy.
- Low-Risk PE: The most prevalent category, typically managed with standard anticoagulation therapy.
Ronak elaborates on the physiological impact of PE:
[04:24] "The heart is essentially two pumps connected in series... the right heart can fail if there's a sudden increase in resistance, causing obstructive shock."
Diagnostic Workup and Initial Management
Vivek outlines the diagnostic steps:
- Imaging: Emphasizes the importance of CT Pulmonary Angiography (CTA) for confirming PE, with bedside echocardiograms reserved for suspected massive or submassive cases.
- Laboratory Tests: Highlights the necessity of CBC, CMP, PT, and PTT to inform anticoagulation strategies.
- Anticoagulation Initiation: Recommends starting with a heparin infusion for its quick reversibility.
Notable Quote:
Vivek [07:46]: "If you have a high clinical suspicion, stabilize the patient empirically, anticoagulate them if you have a really high index of suspicion, and then get the scan when they're stabilized."
Managing the Swollen Leg: Assessing Deep Vein Thrombosis (DVT)
Ronak discusses the approach to diagnosing and managing DVT associated with PE:
- Emergency Assessment: Differentiates between life-threatening clot burdens and those that are not.
- Imaging: Recommends Doppler Ultrasound to assess clot extent, noting the limitation in determining clot age.
- Inflammatory Response Indicators: Points out that elevated WBC counts and local symptoms like erythema and pain may signify acute DVT.
Notable Quote:
Ronak [11:07]: "A clot forming inside of a vein is always an abnormal event and often provokes a local and systemic inflammatory response."
Role of IVC Filters and Thrombolytics
Dan shares insights on the use of Inferior Vena Cava (IVC) filters:
- Indications: Reserved for patients with absolute contraindications to anticoagulation.
- Risks: Highlights the potential for thrombus formation on the filter and the necessity for timely removal to prevent complications.
Vivek addresses the efficacy of catheter-directed thrombolytics:
- Evidence-Based Practice: References the 2017 New England Journal of Medicine study, which found no significant benefit in preventing post-thrombotic syndrome with increased bleeding risks.
- Clinical Implication: Suggests reserving thrombolytics for cases with limb ischemia rather than routine use in proximal DVT.
Notable Quote:
Vivek [19:08]: "The use of catheter-directed thrombolytics does not need to be done for any proximal DVT in the femoral vein unless you have limb compromise."
Determining Duration of Anticoagulation Therapy
Dan explores the factors influencing the length of anticoagulation:
- Provoked vs. Unprovoked VTE: Major provoking factors (e.g., cancer, surgery) typically require limited anticoagulation, whereas unprovoked VTE often necessitates indefinite therapy.
- Patient History: Emphasizes assessing prior VTE episodes, bleeding risks, and family history to tailor treatment duration.
Vivek adds nuances regarding patient-specific factors and the importance of individualized discussions.
Notable Quote:
Dan [22:09]: "The decision is really an individualized discussion... balancing the risk of bleeding against the benefits of preventing recurrent VTE."
Anticoagulation Options: Warfarin vs. DOACs
Ronak advocates for the use of Direct Oral Anticoagulants (DOACs) over Warfarin in patients with active malignancy:
- Efficacy: DOACs are non-inferior to enoxaparin and offer convenience without the dietary restrictions associated with Warfarin.
- Monitoring: While DOACs generally do not require routine monitoring, periodic assessment of liver and kidney function is essential.
Vivek reinforces the practicality of DOACs, noting their minimal dietary interactions and ease of use compared to Warfarin.
Notable Quote:
Ronak [28:14]: "Warfarin was actually inferior to enoxaparin in patients with active malignancy... DOACs appear to be non-inferior."
Dietary Considerations and Lab Monitoring
Dan provides guidance on dietary restrictions and laboratory monitoring for patients on anticoagulants:
- DOACs: No significant dietary restrictions; however, apixaban requires no food for optimal absorption, unlike rivaroxaban.
- Warfarin: Requires consistent vitamin K intake to maintain stable INR levels, but complete avoidance of vitamin K is unnecessary.
Notable Quote:
Dan [32:19]: "There are no dietary restrictions for apixaban... it's important to maintain a stable amount of vitamin K in their diet for Warfarin."
Hypercoagulable Workup Considerations
When addressing post-discharge inquiries about hypercoagulable testing, such as Factor V Leiden mutations, Dan suggests postponing this discussion to a future episode, acknowledging the complexity and evolving perspectives within hematology.
Conclusion
The episode concludes with a comprehensive exploration of VTE management, emphasizing evidence-based practices, individualized patient care, and the practicalities of anticoagulation therapy. The hosts encourage listeners to stay informed through upcoming episodes and provide resources in their show notes for further learning.
Final Quote:
Dan [34:35]: "Peace."
Key Takeaways
- Categorize PE Severity: Differentiating between massive, submassive, and low-risk PE is crucial for appropriate management.
- Anticoagulation Strategy: DOACs are often preferred over Warfarin in cancer-associated VTE due to their efficacy and ease of use.
- IVC Filters and Thrombolytics: Reserved for specific indications, with a preference for minimizing their use to avoid complications.
- Duration of Therapy: Tailored based on whether VTE is provoked or unprovoked, with a focus on balancing recurrence and bleeding risks.
- Dietary and Monitoring Needs: Understanding the requirements and limitations of different anticoagulants to optimize patient outcomes.
Listeners are encouraged to engage with the podcast’s resources and anticipate future episodes that will further elucidate the complexities of VTE management and related hematologic considerations.