Topical nitroglycerin for the treatment of intraoperative microsurgical vasospasm

Background: Papaverine remains a popular agent to treat intraoperative microsurgical vasospasm. However, the recent shortage has forced surgeons to trial antispasmodic agents unproven in microsurgery, but commonly used in other areas. During this shortage we have trialed topical nitroglycerin to break intraoperative vasospasm. This study aims to analyze the outcomes of this medication on flap complications compared with papaverine. Methods: All consecutive free flaps performed for breast reconstruction at a single institution were reviewed. Data collected included patient demographics, co-morbidities, complications and type of antispasmodic agent. Rates of re-exploration, complications and flap salvage were compared between patients receiving nitroglycerin and papaverine. Results: Over 10 years, 991 flaps were treated with antispasmodics: 18 of which were treated with topical nitroglycerin. Patients treated with nitroglycerin tended to have higher BMI (32.1 vs. 27.9, P < 0.01), higher rates of pre-operative chemotherapy (83.3% vs. 51.3%, P < 0.01) and shorter follow-up duration (735 vs. 1691 days, P < 0.01). However, no differences in complications were observed, including: unplanned return to the operating room, flap loss, fat necrosis, infection, hematoma, or seroma. Subgroup analysis with a time-matched cohort of papaverine patients revealed minimal difference in comorbidities and no difference in complications. Conclusions: Substituting topical nitroglycerin for papaverine to treat vasospasm during the shortage did not demonstrate an increased rate of flap loss or return to the operating room, making these medications a safe alternative to papaverine.