Combination Anticoagulation Strategy in Pregnancy With Mechanical Valves: The KYBELE Study

BACKGROUND

Optimal first-trimester anticoagulation is still challenging in pregnant women with mechanical heart valves (MHVs) requiring high-dose warfarin.This multicenter prospective study aims to determine the optimal anticoagulation regimens for pregnant patients with MHVs.

METHODS

All women were allocated to one of three treatment options during first trimester including lone low-molecular-weight heparin (LMWH), combination of LMWH+2.5 mg warfarin, and LMWH+4 mg warfarin. Primary maternal outcome included a combination of death, thromboembolism, severe bleeding, and need for treatment of mechanical valve thrombosis (MVT).Any fetal loss was determined as primary fetal outcome.

RESULTS

The study included 78 pregnancies in 65 women with MHVs.Primary maternal outcome rate was 44%, 12.5%, 3.5%, respectively.The rates of primary maternal outcome (44 vs 3.5%, p<0.001), obstructive MVT (16 vs 0%, p=0.04), MVT requiring treatment (28 vs 0%, p=0.003), and cerebral embolism (24 vs 3.4%, p=0.041) were found to be significantly higher in lone LMWH group compared to LMWH+4 mg warfarin group. Moreover, the rates of primary maternal outcome (12.5 vs 44%, p=0.015) and treatment for MHV thrombus (4.2 vs 28%, p=0.049) were significantly lower in LMWH+2.5 mg warfarin group compared to lone LMWH group.The incidences of fetal loss were 8 (32%) in the lone LMWH group, 8 (33.3%) in LMWH+2.5 mg warfarin group, and 11 (37.9%) in LMWH+4 mg warfarin group (p=0.890 for 3-group).Warfarin related-embryopathy was not observed in any case.

CONCLUSIONS

The combined anticoagulation strategy of LMWH plus low-dose warfarin during the first trimester of pregnancy may result in less maternal complications with comparable fetal outcomes in patients with MHVs.

CONDENSED ABSTRACT

Low-molecular-weight heparin (LMWH) is thought to be safer for the fetus, however it is suspected to be less protective for the mother. To solve this dilemma, the authors suggested a novel anticoagulation strategy in pregnant women with prosthetic valves. Seventy-eight pregnancies of 65 women [median age 32 (27-35) years] were included in the study. A combination of LMWH and a reduced dose warfarin were associated with low rates of thrombus-related complications in pregnant patients with mechanical heart valves.

Development of acute severe right heart failure after transcatheter aortic valve implantation in patient with left ventricle assist device-acquired aortic regurgitation

A 58-year-old man with a left ventricular assist device (LVAD), which had been implanted 1 year earlier, presented with rest dyspnea. Moderate to severe aortic regurgitation (AR), pre-postcapillary pulmonary hypertension, modarete right ventricular (RV) failure, and low cardiac output were observed at presentation. Transcatheter aortic valve implantation (TAVI) was performed to treat the AR and a self-expandable aortic valve was implanted. Within minutes, hypotension, RV and inferior vena cava dilatation, and left atrial (LA) and left ventricular (LV) collapse occurred and persisted despite LVAD speed reduction. It was observed that severe RV failure had developed and venoarterial extracorporeal membrane oxygenation (VA-ECMO) was applied. Following VA-ECMO treatment, the RV dimensions decreased, and the LA and LV dimensions began to increase, as well as the LVAD flow. Weaning from VA-ECMO was unsuccessful and exitus occurred on the fifth day after TAVI secondary to RV failure. It was surmised that the decrease in blood circulation from the aorta to the LV after treatment of severe AR with TAVI caused an acute increase in the cardiac output and the RV preload. The acute increase in the RV preload led to acute severe right heart failure. It is necessary to prepare the RV to compete with an acute increase in preload before TAVI even when there is only modarete RV failure.