Vascular & Perioperative Medicine

Acute pulmonary arterial occlusion abruptly raises RV afterload against a thin-walled chamber never built for high pressure. The RV dilates to maintain stroke volume, which shifts the interventricular septum leftward and impairs LV filling (ventricular interdependence), while RV wall tension rises and coronary perfusion pressure to the RV falls — a combination that can precipitate RV ischemia and a self-reinforcing spiral toward RV failure and obstructive shock in the most severe presentations.

Wells or revised Geneva criteria stratify pretest probability; a negative age-adjusted D-dimer reliably excludes PE in low/intermediate-probability patients, avoiding unnecessary CT. CT pulmonary angiography is the diagnostic standard when D-dimer is positive or probability is high; V/Q scanning is an alternative when contrast is contraindicated (renal failure, pregnancy).

DOACs are first-line for most hemodynamically stable patients — rapid onset, predictable dosing, no routine monitoring. Parenteral anticoagulation (UFH) is preferred when thrombolysis or thrombectomy is being considered, given its short half-life and reversibility.

A multidisciplinary Pulmonary Embolism Response Team (PERT) should guide advanced-therapy decisions in intermediate-to-high-risk (Category C-D) PE. Mechanical thrombectomy is reasonable over anticoagulation alone in Category E1 (persistent hypotension/cardiopulmonary failure) and may be considered in Category D; systemic thrombolysis remains an option where mechanical options are unavailable, weighed against bleeding risk.