Heart transplantation in patients with ventricular assist devices: Impacts of the implantation technique and support duration

Post-transplant survival with pre-transplant durable continuous-flow mechanical circulatory support in a Swiss cohort of heart transplant recipients

BACKGROUND

Worldwide, almost half of all heart transplantation candidates arrive today at their transplant operation with durable continuous-flow mechanical circulatory support (CF-MCS). This evolution is due to a progressive increase of waiting list time and hence an increased risk of haemodynamic worsening. Longer duration of CF-MCS is associated with a higher risk of device-related complications with potential adverse impact on post-transplant outcome as suggested by recent results from the United Network of Organ Sharing of the United States.

METHODS

A 2-centre Swiss heart transplantation programme conducted a retrospective observational study of consecutive patients of theirs who underwent a transplant in the period 2008-2020. The primary aim was to determine whether post-transplant all-cause mortality is different between heart transplant recipients without or with pre-transplant CF-MCS. The secondary outcome was the acute cellular rejection score within the first year post-transplant.

RESULTS

The study participants had a median age of 54 years; 38/158 (24%) were females. 53/158 study participants (34%) had pre-transplant CF-MCS with a median treatment duration of 280 days. In heart transplant recipients with pre-transplant CF-MCS, the prevalence of ischaemic cardiomyopathy was higher (51 vs 32%; p = 0.013), the left ventricular ejection fraction was lower (20 vs 25; p = 0.047) and pulmonary vascular resistance was higher (2.3 vs 2.1 Wood Units; p = 0.047). Over the study period, the proportion of heart transplant recipients with pre-transplant CF-MCS and the duration of pre-transplant CF-MCS treatment increased (2008-2014 vs 2015-2020: 22% vs 45%, p = 0.009; increase of treatment days per year: 34.4 ± 11.2 days, p = 0.003; respectively). The primary and secondary outcomes were not different between heart transplant recipients with pre-transplant CF-MCS or direct heart transplantation (log-rank p = 0.515; 0.16 vs 0.14, respectively; p = 0.81).

CONCLUSION

This data indicates that the strategy of pre-transplant CF-MCS with subsequent orthotopic heart transplantation provides post-transplant outcomes not different to direct heart transplantation despite the fact that the duration of pre-transplant assist device treatment has progressively increased.

Impact of Extracorporeal Membrane Oxygenation on Right Ventricular Function After Heart Transplantation

Aims

Acute right ventricular failure remains a common challenging clinical syndrome in heart transplant (HTx) recipients. While extracorporeal membrane oxygenation (ECMO) is a proven strategy for the treatment of this condition, the outcomes after weaning and during follow up remain understudied. We aimed to evaluate the right-sided heart function in ECMO survivors following HTx.

Methods

Between September 2005 and December 2019, 205 patients with end-stage heart failure who underwent standard orthotopic HTx were enrolled. In total, 68 (33.2%) patients were included in the ECMO group and 137 (66.8%) patients were included in the non-ECMO group.

Results

Of the 68 patients in the ECMO group, 42 (61.8%) were successfully weaned from ECMO. After a median follow-up period of 53 months, there were 25 (59.5%) and 27 (23.7%) deaths in the ECMO and non-ECMO groups (P = 0.023), respectively. Systolic pulmonary artery pressure (SPAP) before discharge (P = 0.003) was the unique predictor of all-cause mortality during follow up. Meanwhile, patients in the ECMO group with more than moderate SPAP increase before discharge had higher mortality than patients in the non-ECMO group without such increase (P = 0.005).

Conclusions

Recipient right-sided heart characteristics were strong predictors of ECMO need after HTx. ECMO patients had high mortality in the perioperative and follow-up periods, and the changes in right ventricular function in ECMO patients may be associated with pulmonary vessel injury before and after HTx.

Impact of pretransplant left ventricular assist device support duration on outcome after heart transplantation

 

OBJECTIVES

Heart transplantation after left ventricular assist device (LVAD) implantation remains challenging. It is still unclear whether its support duration impacts the outcome after transplantation.

METHODS

All patients undergoing heart transplantation between 2010 and 2021 at a single department after previous left ventricular assistance were retrospectively reviewed and divided into 4 different study groups with regard to the duration of LVAD support to examine the impact on the postoperative morbidity and mortality.

RESULTS

A total of n = 198 patients were included and assigned to the 4 study groups (group 1: <90 days, n = 14; group 2: 90 days to 1 year, n = 31; group 3: 1–2 years, n = 29; group 4: >2 years, n = 24). Although there were no differences between the 4 groups concerning relevant mismatch between the recipients and donors, the incidence of primary graft dysfunction was numerically increased in patients with the shortest support duration, and also those patients with >1 year of support (group 1: 35.7%, group 2: 25.8%, group 3: 41.4%, group 4: 37.5%, P = 0.63). The incidence of acute graft rejection was by trend increased in patients of group 1 (group 1: 28.6%, group 2: 3.3%, group 3: 7.1%, group 4: 12.5%, P = 0.06). Duration of LVAD support did not impact on perioperative adverse events (infections, P = 0.79; acute kidney injury, P = 0.85; neurological events, P = 0.74; thoracic bleeding, P = 0.61), neither on postoperative survival (1-year survival: group 1: 78.6%, group 2: 66.7%, group 3: 80.0%, group 4: 72.7%, P = 0.74).

CONCLUSION

We cannot identify a significant impact of the duration of pretransplant LVAD support on postoperative outcome; therefore, we cannot recommend a certain timeframe for transplantation of LVAD patients.

Levosimendan for Treatment of Primary Graft Dysfunction After Heart Transplantation: Optimal Timing of Application

OBJECTIVES

Primary graft dysfunction remains a serious problem after heart transplant. Pharmacological treatment with the calcium sensitizer levosimendan may be an additive treatment for primary graft dysfunction.

MATERIALS AND METHODS

Patients undergoing heart transplant between 2010 and 2020 were retrospectively reviewed and divided depending on postoperative treatment with (n = 41) or without (n = 109) levosimendan. Recipients who received levosi mendan were further divided with regard to timing of levosimendan application (early group: started ≤48 hours posttransplant [n = 23]; late group: started >48 hours posttransplant [n = 18]).

RESULTS

Patients who received levosimendan treatment displayed a remarkable incidence (87.8%) of postoperative primary graft dysfunction with need for venoarterial extracorporeal membrane oxygenation and therefore often presented with perioperative morbidity. Patient with early application of levosimendan showed significantly decreased duration of venoarterial extracorporeal membrane oxygenation support (5.1 ± 3.5 days vs 12.6 ± 9.3 days in those with late application; P < .01) and decreased mortality during venoarterial extracorporeal membrane oxygenation support (0.0% vs 33.3% in early vs late group; P < .01). In addition, compared with patients with late levosimendan application, patients with early application needed fewer blood transfusions (P < .05), had shorter ventilation times (279 ± 235 vs 428 ± 293 h; P = .03), and showed a trend of reduced incidence of postoperative renal failure (69.6% vs 94.4%; P = .06). Moreover, survival analyses indicated an increased survival for patients with early start of levosimendan therapy within the first 48 hours after heart transplant (P = .09).

CONCLUSIONS

Pharmacotherapy with levosimendan may be a promising additive in the treatment of primary graft dysfunction after heart transplant. With administration of levosimendan within the first 48 hours posttransplant, rates of successful weaning from venoarterial extracorporeal membrane oxygenation and outcomes after heart transplant were shown to increase.

Complications of left ventricular assist devices causing high urgency status on waiting list: impact on outcome after heart transplantation

Aims

Heart transplantation (HTx) represents optimal care for advanced heart failure. Left ventricular assist devices (LVADs) are often needed as a bridge‐to‐transplant (BTT) therapy to support patients during the wait for a donor organ. Prolonged support increases the risk for LVAD complications that may affect the outcome after HTx.

Methods and results

A total of 342 patients undergoing HTx after LVAD as BTT in a 10‐year period in two German high‐volume HTx centres were retrospectively analysed. While 73 patients were transplanted without LVAD complications and with regular waiting list status (T, n = 73), the remaining 269 patients were transplanted with high urgency status (HU) and further divided with regard to the observed leading LVAD complications (infection: HU1, n = 91; thrombosis: HU2, n = 32; stroke: HU3, n = 38; right heart failure: HU4, n = 41; arrhythmia: HU5, n = 23; bleeding: HU6, n = 18; device malfunction: HU7, n = 26). Postoperative hospitalization was prolonged in patients with LVAD complications. Analyses of perioperative morbidity revealed no differences regarding primary graft dysfunction, renal failure, and neurological events except postoperative infections. Short‐term survival, as well as Kaplan–Meier survival analysis, indicated comparable results between the different study groups without disadvantages for patients with LVAD complications.

Conclusions

Left ventricular assist device therapy can impair the outcome after HTx. However, the occurrence of LVAD complications may not impact on outcome after HTx. Thus, we cannot support the prioritization or discrimination of HTx candidates according to distinct mechanical circulatory support‐associated complications. Future allocation strategies have to respect that device‐related complications may define urgency but do not impact on the outcome after HTx.

Minimally Invasive Left Ventricular Assist Device Insertion Facilitates Subsequent Heart Transplant

OBJECTIVE

We have observed that minimally invasive left ventricular assist device (LVAD) insertion leads to more facile re-entry and easier cardiac transplantation. We hypothesize minimally invasive LVAD implantation results in improved outcomes at the time of subsequent heart transplant.

METHODS

All adults undergoing cardiac transplantation between October 2015 and March 2019 at our institution were retrospectively reviewed. Those bridged to transplantation with a HeartWare HVAD were identified and divided into 2 cohorts based upon the surgical approach: those who underwent HVAD placement by conventional sternotomy versus minimally invasive insertion via lateral thoracotomy and hemisternotomy (LTHS). Patient demographics, as well as perioperative transplant outcomes, including survival, length of stay (LOS), blood utilization, ischemic time, bypass time, and postoperative extracorporeal membrane oxygenation (ECMO) were compared between cohorts.

RESULTS

Forty-two patients were bridged to heart transplant with a HVAD implanted via either sternotomy (n = 22) or LTHS technique (n = 20). Demographics were similar between groups. There was 1 predischarge death in the sternotomy group and none in the LTHS group. Body surface area, cardiopulmonary bypass time, ischemic time, ECMO utilization, and reoperation for bleeding were similar. Red blood cell units transfused were significantly lower in the LTHS cohort (3.0 [1.0-5.0] vs 6.0 [2.5-10.0] P = 0.046). The LTHS cohort had a significantly shorter hospital LOS (12.0 [11.0-28.0] vs 22.5 [15.7-41.7] P = 0.022) with a trend toward shorter intensive care unit LOS (6.0 [5.0-10.5] vs 11.0 [6.0-21.5] days P = 0.057).

CONCLUSIONS

Minimally invasive HVAD implantation improves outcomes at subsequent heart transplantation, resulting in shorter LOS and less red cell transfusion. Larger multi-institutional studies are necessary to validate these findings.

The Year in Cardiothoracic Transplantation Anesthesia: Selected Highlights from 2019

The highlights in cardiothoracic transplantation focus on the recent research pertaining to heart and lung transplantation, including expansion of the donor pool, the optimization of donors and recipients, the use of mechanical support, the perioperative and long-term outcomes in these patient populations, and the use of transthoracic echocardiography to diagnose rejection.