To prophylax or not, and how much and how long? Controversies in VTE prevention for medical inpatients, including COVID-19 inpatients

The fi eld of thromboprophylaxis for acutely ill med i cal patients, includ ing those hos pi tal ized for COVID -19, is rap idly evolv-ing both in the inpa tient set ting and the imme di ate post - hos pi tal dis charge period. Recent data reveal the impor tance of incorporating holistic thromboembolic outcomes that encompass both venous thromboembolism (VTE) and arterial throm bo em bo lism, as thromboprophylaxis with low -dose direct oral anti co ag u lants has been shown to reduce major and fatal vas cu lar events, espe cially against a back ground of dual path way inhi bi tion with aspi rin. In addi tion, recent post hoc ana ly ses from ran dom ized trial data have established 5 key bleed ing -risk fac tors that, if removed, reveal a low - bleed ing - riskmed i cally ill pop u la tion and, con versely, key indi vid ual risk fac tors, such as advanced age, a past his tory of can cer or VTE, an ele vated D -dimer, or the use of a val i dated VTE risk score - the IMPROVE VTE score using established cut offs - to predict a high-VTE-risk medically ill population that benefits from extended postdischarge thromboprophylaxis. Last, thromboprophylaxis of a high -throm botic -risk sub set of med i cally ill patients, those with COVID -19, is rap idly evolv ing, both dur ing hos pi tal i za tion and post dis charge. This arti cle reviews 3 con tro ver sial top ics in the thromboprophylaxis of hos pi tal ized acutely ill med i cal patients: (1) clin i cal rel e vance of key effi cacy and safety out comes incor po rated into ran-dom ized tri als but not incor po rated into rel e vant antithrombotic guide lines on the topic, (2) the use of indi vid ual risk factors or risk models of low-bleeding-risk and high-thrombotic-risk subgroups of medically ill inpatients that benefit from extended thromboprophylaxis, and (3) thromboprophylaxis of hos pi tal ized COVID -19 patients, includ ing extended postdischarge thromboprophylaxis.