Case Presentation: A 28-year-old, 447 lb man with hypothyroidism and depression was hospitalized for neurosurgical intervention for severe lumbar spinal stenosis. He had one risk factor from the Revised Cardiac Risk Index due to the spinal procedure, and his EKG, echocardiogram, and renal function were normal. He had no history of diabetes, TIA/CVA, or cardiac and lung disease. His Padua score was 1 for body mass index (BMI) >30 with no other criteria met. While medically optimizing him for the procedure, he developed new-onset, symptomatic atrial fibrillation with rapid ventricular response and became unresponsive the following day. He was found with a rapid and thready pulse, apneic breaths, and progressive cyanosis, and after receiving rescue breaths, he regained consciousness. CT of the chest revealed a massive saddle pulmonary embolism (PE) and deep vein thromboses (DVTs) in the right popliteal and posterior tibial veins. He was given tPA and was eventually put on apixaban.
Discussion: This case demonstrates the significance of incorporating BMI into venous thromboembolism (VTE) risk assessment. Studies confirm that obesity is associated with a 6.2-fold increased susceptibility to VTE, and a 3.9 million participant meta-analysis found that obese individuals have a 62% increased chance of VTE compared to those with normal BMI. This patient’s Padua score of 1 is considered low, with pharmacologic prophylaxis not indicated, yet he was unresponsive with acute arrhythmia secondary to a massive saddle PE. The Padua Prediction Score utilizes BMI >30 in determining anticoagulation for hospitalized patients with additional comorbidities but does not distinguish nor stratify between classes I, II, and III of obesity. The Caprini Score for VTE includes BMI >25 as a criterion but was designed for surgical candidates and does not include further weight stratification. Notably, in a cohort of over 1.25 million patients, neither Caprini nor Padua showed clinically meaningful ability to predict VTE. This suboptimal performance persisted across surgical and non-surgical patients, indicating that these models may not be sufficiently refined for predicting VTE in a general hospital setting. Further, the Wells Criteria is commonly used for initial risk determination but performs weakly in hospitalized patients on anticoagulation and thromboprophylaxis and does not identify weight in its calculation. These findings show the association between obesity and VTE while highlighting the limitations of existing VTE risk stratification tools, which either exclude BMI or fail to differentiate patients with moderate and severe obesity. Current methods are particularly unhelpful for obese patients with no other VTE comorbidities despite the well-established link between obesity and VTE.
Conclusions: Although obesity is a significant independent risk factor for VTE and PE, BMI is not considered as a critical component in current screening and risk assessment methods. This patient with a BMI of 60 would have benefited from recognizing obesity independently for DVT/PE in the absence of any other comorbidities. Given the evidence linking obesity to VTE, establishing new approaches that take weight alone into account with VTE likelihood is crucial, given the rising prevalence of obesity in developed nations. By identifying body habitus as a distinct risk indicator, these models may become more accurate and help avoid consequences from VTE in the future.
