Burden of Cardiovascular Events and Bleeding Is High in Myelodysplastic Syndromes

Background: Myelodysplastic syndromes (MDS) and acute myeloid leukaemia (AML) patients are older and suffer with cardiovascular (CV) diseases. Management of these patients with antiplatelet and anticoagulation therapy is challenging as thrombocytopenia can increase the risk of bleeding.

Aim: To assess burden and CV disease related mortality, review of anticoagulant /antiplatelet therapy and bleeding complications in MDS and oligoblastic AML patients.

Methods:

Electronic medical records of 910 MDS and oligoblastic AML patients enrolled in the South Australian MDS (SA-MDS) registry were reviewed. CV risk factors, CV and bleeding events requiring or occurring during hospitalisation, anticoagulation and/or antiplatelet therapy information were collected.

Platelet counts of <100, <50 and <20 (x10⁹/L) were defined as mild, moderate and severe thrombocytopenia respectively. Severity of bleeding events was classified using modified International Society of Thrombosis and Hemostasis (ISTH) classification. MDS patients require regular RBC transfusion, hence fall in hemoglobin ≥20 gm/L or ≥2 units of RBC transfusion were not used for defining major bleeding.

Results: At the time of MDS diagnosis, 72% (658/910) and 42% (386/910) patients had ≥1 and ≥2 CV risk factors. Twenty-five percent patients required hospitalization for CV events prior to the MDS diagnosis and their median OS was significantly poor compared to patients who did not have CV events (Figure 1A).

During median follow up of 28 months after MDS diagnosis, 27.5% (251/910) patients were admitted with or developed CV events during hospitalization. In a Cox-regression analysis age, absolute monocyte count, CV risk factors and prior CV events were independent predictors of CV events following MDS diagnosis (Figure 1B).

The most frequent CV events were arrhythmia (137/399; 34%), congestive cardiac failure (129/399; 32%), and ischemic heart disease (94/399; 23%). Atrial fibrillation (AF) contributed towards 78% (108/137) of all arrhythmias. 39% of AF occurred in the setting of infections and 12% patients died during the same hospitalization or were palliated. 89% of AF patients had a CHADS2VASc2 score ≥2, however only 30% (20/65) and 24% (16/65) events with available information were treated with anticoagulation and antiplatelet therapy respectively. While 60% (39/65) AF events did not receive antiplatelet or anticoagulation therapies. Four AF patients developed ischemic stroke following MDS diagnosis and five patients had stroke before MDS diagnosis and were subsequently diagnosed with AF. Importantly, 36% (34/94) AF patients developed 45 bleeding events. The frequency of bleeding events was not significantly different between patients treated with anticoagulation/antiplatelet therapy versus who were not treated (13.8% vs. 13.6%).

Although, cumulative incidence of bleeding and CV events was similar at 29% and 28% at five-years (Figure 1C-D), only some patients had both events. Of the 387 patients, 39% (n= 152) and 39% (n=153) patients required hospitalization only for CV or bleeding events, while only 21% (82/387) required hospitalization for both bleeding and CV events. Identifying these three groups early is crucial to optimize their outcome.

Of the 387 bleeding events, 88 (24%) were major and 296 (76%) were clinically relevant minor bleeding. Notably, 127, 47 and 15 bleeding events were gastrointestinal, intracranial and intraocular respectively. While 50% bleeding events occurred in the setting of moderate to severe thrombocytopenia, 19% and 31% of bleeding events occurred at platelet counts of >50-100 and >100x10⁹/L respectively (Figure 1E).

Details of anticoagulation/antiplatelet therapy were available for 66% (161/243) of bleeding events. Importantly, 76% of bleeding events occurred without anticoagulation and antiplatelet therapy, while 10% and 13% bleeding occurred while on anticoagulation therapy and antiplatelet therapy respectively.

Conclusions: Our analysis demonstrates a significant burden of CV and bleeding in MDS. Only 23% of all bleeding events occurred while on anticoagulation therapy and some patients with recurrent CV events did not require hospitalization for bleeding. However, large numbers of CV events are sub-optimally managed due to perceived excess risk of bleeding. Therefore, guidelines for anticoagulation and/or antiplatelet therapy are required for MDS patients.

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