Bradykinin or Mast Cells? Decoding ACE inhibitor-induced angioedema

In this episode, Dr. Thomas Buttgereit welcomes Dr. Alexis Bocquet from the French National Center for Angioedema in Grenoble to discuss one of the most challenging forms of drug-induced angioedema — ACE inhibitor–induced angioedema. They discuss🔹 Why are ACE inhibitors among the most prescribed cardiovascular drugs worldwide? 🔹 How can physicians distinguish bradykinin-mediated from mast-cell-mediated angioedema? 🔹 What are the key risk factors for developing ACE inhibitor–induced angioedema? 🔹 How can the new diagnostic core support clinicians in practice? Dr. Bocquet shares findings from a French multicenter study conducted in Grenoble and Réunion Island, where he and his colleagues identified four clinical criteria that accurately differentiate ACE inhibitor–induced angioedema from other forms. He also explains the score they developed — a five-point tool that predicts diagnosis with more than 90% accuracy — and offers practical advice on treatment, including when to use icatibant or C1 inhibitor concentrate in acute care. Join us for a scientifically rich and practical conversation on how to diagnose and manage one of the most life-threatening but underrecognized types of angioedema. Key Learnings from the Epesode:ACE inhibitors are widely used for heart failure, hypertension, and kidney protection but can rarely cause bradykinin-mediated angioedema. The pathophysiology involves inhibition of bradykinin degradation, leading to increased vascular permeability and swelling. Risk factors include age over 65, female sex, African or Afro-Caribbean ethnicity, concomitant use of NSAIDs, smoking, cardiovascular comorbidities, and genetic variants in bradykinin receptor B2 or aminopeptidase N. In a French bicenter study (Grenoble & Réunion Island, 2019–2022), 126 patients were evaluated for angioedema without hives; 49 were confirmed as ACE inhibitor–induced, and 44 as mast cell-mediated. The four diagnostic factors identified were: No relapse after discontinuation of ACE inhibitor Attack duration longer than 24 hours Hospitalization in intensive care Fewer than three previous angioedema attacks These factors formed the five-point score: 0–2 points → Likely mast cell angioedema 4–5 points → >90% probability of ACE inhibitor–induced angioedema Persistent angioedema after stopping ACE inhibitors usually indicates mast- cell-mediated angioedema or CSU, not ACE inhibitor–induced angioedema. Genetic testing may help rule out hereditary angioedema with normal C1 inhibitor. Tranexamic acid shows little benefit in ACE inhibitor–induced angioedema. Treatment recommendations: Icatibant is first-line off-label therapy with rapid efficacy. C1 inhibitor concentrate is an effective alternative. Both are off-label but justified in life-threatening upper-airway cases.The team plans a national prospective validation of the diagnostic Score for ACE inhibitor-induced anigoedema across France in 2025. Chapters:00:00 Introduction to ACE Inhibitor Induced Angioedema03:31 Understanding ACE Inhibitors and Their Benefits06:00 Pathophysiology and Risk Factors of Angioedema09:02 Research Insights from CRIAC and Study Design11:30 Clinical Features and Diagnosis of Angioedema14:01 Proposed Diagnostic Score for Angioedema16:40 Treatment Options for ACE Inhibitor Induced AngioedemaDo you have suggestions for future episodes? Please provide feedback and offer your suggestions for future topics and expert selection here.Feedback form ATA: ⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠https://forms.office.com/e/ZWxx3D4Cmr⁠⁠