Long-term left ventricular support in patients with a mechanical aortic valve

Aortic Thrombosis in Patients on Mechanical Circulatory Support: A Systematic Literature Review

BACKGROUND

Aortic valve (AV) thrombosis is an uncommon but ominous complication in patients managed with mechanical circulatory support (MCS) devices. In this systematic review, we summarised the data on clinical presentations and outcomes in such patients.

METHODS

We searched articles on PubMed and Google Scholar, reporting at least one adult patient with aortic thrombosis on MCS support and where the individual patient data could be extracted. We grouped the patients by the type of MCS (temporary or durable), and the type of the AV (prosthetic, surgically modified, or native) RESULTS: We identified reports on six patients with aortic thrombus on short-term MCS, and on 41 patients on durable left ventricular assist devices (LVADs). On temporary MCS, AV thrombus typically causes no symptoms and is found incidentally pre- or intra-operatively. For those with durable MCS, the occurrence of aortic thrombus forming on prosthetic or surgically modified valves appears to be more related to the intervention on the valve, rather than from the presence of LVAD. The mortality in this group was 18%. In patients with native AV on durable LVAD support, 60% of patients presented with acute myocardial infarction, acute stroke, or acute heart failure, and mortality in this cohort was 45%. In terms of management, heart transplantation was most successful.

CONCLUSIONS

While the outcomes of aortic thrombosis were good in patients where temporary MCS was used in the setting of aortic valve surgery, patients with native AV who develop this complication on durable LVAD have high morbidity and mortality. Cardiac transplantation should be strongly considered in eligible candidates because other therapies provide inconsistent results.

A simple closure method for a mechanical aortic valve in left ventricular assist device implantation

Because a mechanical aortic valve is a contraindication for the implantation of left ventricular assist device, complicated additional procedures such as a replacement with a bioprosthesis and a closure of the left ventricular outflow tract are required to implant the device. Among such procedures, a sandwich plug technique using vascular clips is one of the simple and feasible procedures. However, this technique requires an off-label use of vascular clips within the aorta that could be associated with a risk of dislodgement and embolization. Thus, we developed a modified sandwich technique without using vascular clips, where the valve leaflets were fixed in the closed position using felt patches and sutures instead of vascular clips. This modified technique is a simple and secure method to close the mechanical aortic valve with the minimum use of artificial materials.

Survival following a concomitant aortic valve procedure during left ventricular assist device surgery: an ISHLT Mechanically Assisted Circulatory Support (IMACS) Registry analysis

Aims

The aim of this study was to compare early‐ and late‐term survival and causes of death between patients with and without a concomitant aortic valve (AoV) procedure during continuous‐flow left ventricular assist device (LVAD) surgery.

Methods and results

All adult primary continuous‐flow LVAD patients on the International Society of Heart and Lung Transplantation (ISHLT) Mechanically Assisted Circulatory Support (IMACS) Registry (n = 15 267) were included in this analysis and stratified into patients submitted to a concomitant AoV procedure (AoV replacement or AoV repair) and patients without an AoV procedure. The primary outcome was early (≤90 days) survival post‐LVAD surgery. Secondary outcomes were late survival (survival during the entire follow‐up period) and conditional survival (in patients who survived the first 90 days post‐LVAD surgery), and determinants. Patients who underwent concomitant AoV replacement (n = 457) had significantly reduced late survival compared with patients with AoV repair (n = 328) or without an AoV procedure (n = 14 482) (56% vs. 61% and 62%, respectively; P = 0.001). After adjustment for other significant predictors, concomitant AoV replacement remained an independent predictor for early [hazard ratio (HR) 1.226, 95% confidence interval (CI) 1.037–1.449] and late (HR 1.477, 95% CI 1.154–1.890) mortality. However, patients undergoing AoV replacement or repair, in whom the presence of moderate‐to‐severe AoV regurgitation was diagnosed prior to LVAD implantation, had survival similar to patients not undergoing AoV interventions.

Conclusions

Concomitant AoV surgery in patients undergoing LVAD implantation is an independent predictor of mortality. Additional research is needed to determine the best AoV surgical strategy at the time of LVAD surgery.

A case series of patients with left ventricular assist devices and concomitant mechanical heart valves

Mechanical heart valves left in situ at the time of left ventricular assist device (LVAD) implantation are thought to potentially increase the risk of thromboembolism. Recommendations exist to replace dysfunctional mechanical mitral valves and any mechanical aortic valves at the time of LVAD implantation. Due to potential increases in cardiopulmonary bypass time and associated comorbidities with valve replacement, leaving a functional mechanical valve in place at LVAD implantation has been suggested to be a safe option. We retrospectively reviewed all patients with prior mechanical mitral or aortic valves undergoing LVAD implantation at our center between 2012 and 2017. Echocardiograms were read by a single cardiologist to assess for mechanical valve dysfunction. We identified 15 patients. Five patients had major bleeding requiring transfusion. On follow-up, 2 patients had hemorrhagic stroke and 2 had transient ischemic attach/ischemic stroke. In addition, 2 patients had LVAD thrombosis and 2 patients had LVAD driveline malfunction. Mild mechanical valve regurgitation was identified on follow-up echocardiograms of 2 patients. Rate of complications in patients with mechanical valves undergoing LVAD implantation was comparable to that reported for the general LVAD population. Leaving a functional mechanical valve in place at the time of LVAD implantation could be a reasonable alternative to valve replacement. More data are required to further guide patient care in these individuals.

Effects of vitamin K epoxide reductase complex 1 gene polymorphisms on warfarin control in Japanese patients with left ventricular assist devices (LVAD)

PURPOSE

This study aimed to investigate relationships between times in therapeutic range (TTR) or warfarin sensitivity indexes (WSI) and VKORC1-1639G>A and CYP2C9 polymorphisms in patients with left ventricular assist devices (LVAD).

METHODS

Severe heart failure patients who received LVAD from January 1, 2013 to October 31, 2017 were recruited. Relationships between TTR or WSI and VKORC1-1639G>A and CYP2C9 gene polymorphisms were investigated immediately after LVAD implantation (period 1) and immediately prior to hospital discharge (period 2).

RESULTS

Among 54 patients, 31 (72.1%) had VKORC1-1639AA and CYP2C9*1/*1 (AA group) polymorphisms and 12 (27.9%) had VKORC1-1639GA and CYP2C9*1/*1 (GA group) polymorphisms. During period 1, mean prothrombin time-international normalized ratio (PT-INR) values were significantly higher in the AA group than in the GA group (2.21 vs. 2.05, p < 0.0001). Mean WSI values were 1.68-fold greater in the AA group than in the GA group (1.14 vs. 0.68, p < 0.0001). In addition, times below the therapeutic range (TBTR) in the GA group were significantly greater than in the AA group during period 1 (39.8 vs. 28.3%, p = 0.032), and insufficient PT-INR was more frequent in the GA group than in the AA group. However, mean PT-INR values during period 2 did not differ and no significant differences in TTR, TATR, and TBTR values were identified. In subsequent multivariable logistic regression analyses, the VKORC1-1639GA allele was significantly associated with insufficient anticoagulation.

CONCLUSION

Patients with the VKORC1-1639GA and CYP2C9*1/*1 alleles may receive insufficient anticoagulation therapy during the early stages after implantation of LVAD, and VKORC1-1639G>A and CYP2C9 genotyping may contribute to more appropriate anticoagulant therapy after implantation of LVAD.