Impact of low-dose B-type natriuretic peptide infusion on urine output after total artificial heart implantation

Three-month outcomes after the implantation of two HeartMate 3 devices in total artificial heart configuration

BACKGROUND

Total artificial heart (TAH) implantation is a rarely performed procedure. Contrarily, left ventricular assist device (VAD) implantation is rather common in many centers. As transplantation is quantitatively limited cardiac replacement with artificial hearts is a viable alternative in the treatment of severe biventricular heart failure. An alternative to TAH is the implantation of two VADs in a TAH configuration. We hereby present the first multi-center study on 3-months outcomes of patients treated by cardiectomy and placement of two HeartMate 3s in a TAH configuration.

METHODS

We retrospectively investigated a cohort of 15 patients that underwent HM3-TAH-implantation at three international institutions. Follow-up was 3 months after implantation. Baseline, intra- and postoperative parameters as well as survival data and adverse events were collected.

RESULTS

A total of 1089 days on HM3-TAH were observed. Thirty-day survival after HM3-TAH implantation was 53% (8/15) and three month survival was 40% (6/15). The longest duration on device was 274 days. Causes of death were multi-organ failure, sepsis, and neurological adverse events. No technical complications were documented. Two patients remained on the device. Four patients (26%) were successfully bridged to transplantation.

CONCLUSIONS

The implantation of two HeartMate 3s in a TAH configuration is a last resort and off-label concept in cases of extreme biventricular heart failure. In a diligently selected patient cohort, HM3-TAH implantation is a feasible method to increase the chance of survival in a severely ill patient cohort and successfully bridge patients to heart transplantation that would otherwise have died.

Heart transplantation after total artificial heart bridging-Outcomes over 15 years

BACKGROUND

Data are limited on outcomes after heart transplantation in patients bridged-to-transplantation (BTT) with a total artificial heart (TAH-t).

METHODS

The UNOS database was used to identify 392 adult patients undergoing heart transplantation after TAH-t BTT between 2005 and 2020. They were compared with 11 014 durable left ventricular assist device (LVAD) BTT patients and 22 348 de novo heart transplants (without any durable VAD or TAH-t BTT) during the same period.

RESULTS

TAH-t BTT patients had increased dialysis dependence compared to LVAD BTT and de novo transplants (24.7% vs. 2.7% vs. 3.8%) and higher levels of baseline creatinine and total bilirubin (all p < .001). After transplantation, TAH-t BTT patients were more likely to die from multiorgan failure in the first year (25.0% vs. 16.1% vs. 16.1%, p = .04). Ten-year survival was inferior in TAH-t BTT patients (TAH-t BTT 53.1%, LVAD BTT 61.8%, De Novo 62.6%, p < .001), while 10-year survival conditional on 1-year survival was similar (TAH-t BTT 66.8%, LVAD BTT 68.7%, De Novo 69.0%, all p > .20). Among TAH-t BTT patients, predictors of 1-year mortality included higher baseline creatinine and total bilirubin, mechanical ventilation, and cumulative center volume <20 cases of heart transplantation involving TAH-t BTT (all p < .05).

CONCLUSION

Survival after TAH-t BTT is acceptable, and patients who survive the early postoperative phase experience similar hazards of mortality over time compared to de novo transplant patients and durable LVAD BTT patients.

Predictors of Renal Failure in Patients Treated With the Total Artificial Heart

BACKGROUND

The incidence of hemodialysis (HD)-dependent renal failure after total artificial heart (TAH) implantation is high. We sought to determine the preoperative predictors of HD after TAH implantation.

METHODS AND RESULTS

We studied 87 patients after TAH implantation at our institution between April 2006 and March 2017. Baseline clinical data were obtained from the medical records, and patients were followed until death or heart transplantation. We performed logistic regression analysis to identify predictors of HD after TAH implantation. Of the patients, 24 (28%) required postimplantation HD. Those requiring HD were more likely to have histories of coronary artery disease (58% vs 29%; P = 0.01), required preoperative membrane oxygenation (33% vs 4.8%; P = 0.001) and had lower baseline estimated glomerular filtration rates (54 ± 29 vs 67 ± 24 mL/min/1.73m²; P = 0.04). Patients requiring HD were at a higher risk of death on device at 1 year (33% vs 5%, P = 0.001; log rank test: P =0.001, hazard ratio 6.6 [95% CI:1.8-23], P = 0.003).

CONCLUSIONS

The incidence of postimplantation HD is high and is associated with increased likelihood of mortality. Lower baseline estimated glomerular filtration rates, histories of coronary artery disease and preoperative membrane oxygenation support are predictors of postimplantation requirement of HD. These data may help to identify patients at risk for adverse outcomes after TAH implantation.

Perioperative Care of the Patient With the Total Artificial Heart

Advanced heart failure continues to be a leading cause of morbidity and mortality despite improvements in pharmacologic therapy. High demand for cardiac transplantation and shortage of donor organs have led to an increase in the utilization of mechanical circulatory support devices. The total artificial heart is an effective biventricular assist device that may be used as a bridge to transplant and that is being studied for destination therapy. This review discusses the history, indications, and perioperative management of the total artificial heart with emphasis on the postoperative concerns.

Getting to the Heart of the Matter: Review of Treatment of Cardiorenal Syndrome

Acute decompensated heart failure is a common cause of hospitalization with worsening kidney function or acute kidney injury often complicating the admission, which can result in further dysfunction of both systems in the form of a cardiorenal syndrome. Therapy in this arena has been largely empiric as rigorous clinical trial data to inform therapeutic choices are lacking. Here we review and discuss the available clinical evidence for common approaches to the management of this condition. A multidisciplinary approach to the care of patients with cardiorenal syndrome that relies on the experience of nephrologists and cardiologists to individualize treatment is critical given the paucity of rigorous clinical trial data.

Renal Function Recovery with Total Artificial Heart Support

Heart failure patients requiring total artificial heart (TAH) support often have concomitant renal insufficiency (RI). We sought to quantify renal function recovery in patients supported with TAH at our institution. Renal function data at 30, 90, and 180 days after TAH implantation were analyzed for patients with RI, defined as hemodialysis supported or an estimated glomerular filtration rate (eGFR) less than 60 ml/min/1.73 m. Between January 2008 and December 2013, 20 of the 46 (43.5%) TAH recipients (age 51 ± 9 years, 85% men) had RI, mean preoperative eGFR of 48 ± 7 ml/min/1.73 m. Renal function recovery was noted at each follow-up interval: increment in eGFR (ml/min/1.73 m) at 30, 90, and 180 days was 21 ± 35 (p = 0.1), 16.5 ± 18 (p = 0.05), and 10 ± 9 (p = 0.1), respectively. Six patients (30%) required preoperative dialysis. Of these, four recovered renal function, one remained on dialysis, and one died. Six patients (30%) required new-onset dialysis. Of these, three recovered renal function and three died. Overall, 75% (15 of 20) of patients' renal function improved with TAH support. Total artificial heart support improved renal function in 75% of patients with pre-existing significant RI, including those who required preoperative dialysis.

The total artificial heart

The total artificial heart (TAH) is a form of mechanical circulatory support in which the patient's native ventricles and valves are explanted and replaced by a pneumatically powered artificial heart. Currently, the TAH is approved for use in end-stage biventricular heart failure as a bridge to heart transplantation. However, with an increasing global burden of cardiovascular disease and congestive heart failure, the number of patients with end-stage heart failure awaiting heart transplantation now far exceeds the number of available hearts. As a result, the use of mechanical circulatory support, including the TAH and left ventricular assist device (LVAD), is growing exponentially. The LVAD is already widely used as destination therapy, and destination therapy for the TAH is under investigation. While most patients requiring mechanical circulatory support are effectively treated with LVADs, there is a subset of patients with concurrent right ventricular failure or major structural barriers to LVAD placement in whom TAH may be more appropriate. The history, indications, surgical implantation, post device management, outcomes, complications, and future direction of the TAH are discussed in this review.

Mechanical circulatory support devices in the ICU

The medical community has used implantable mechanical circulatory support devices at increasing rates for patients dying from heart failure and cardiogenic shock. Newer-generation devices offer a more durable and compact option when compared with bulky early-generation devices. This article is a succinct introduction and overview of the hemodynamic principles and complications after device implantation for ICU clinicians. We review the concepts of device physiology, clinical pearls for perioperative management, and common medical complications after device implantation.

Heart and lung transplantation

PURPOSE OF REVIEW

Every year, thousands of heart and lung transplants are performed worldwide. As experience and clinical acumen advance, both fields are continually evolving. This review elucidates and describes many of the recent changes in practice and future directions of heart and lung transplantation. Preoperative, intraoperative and postoperative developments are presented with supporting evidence in these continually evolving fields.

RECENT FINDINGS

The field of heart transplantation is continually adapting to the growing use of mechanical circulatory support devices as bridge to transplant and for postoperative support. Recent modifications in surgical technique have contributed to improved outcomes.Lung transplantation advancements include the increasing use of extracorporeal membrane oxygenation during the perioperative period. Lobar transplantation and ex-vivo lung perfusion techniques may aid in providing successful lung grafts to those with potentially long wait list times.Rates of rejection continue to decline in both fields as immunosuppression regimens are improved and modified.

SUMMARY

This review investigates and summarizes the recent changes and advancements in heart and lung transplantation. Mechanical circulatory support and extracorporeal membrane oxygenation are increasingly used in the perioperative setting, and continuing research will evaluate their safety profiles. Optimizing and tailoring immunosuppression regimens for transplant recipients continue to be the subject of ongoing investigation.

Implantation of the syncardia total artificial heart

With advances in technology, the use of mechanical circulatory support devices for end stage heart failure has rapidly increased. The vast majority of such patients are generally well served by left ventricular assist devices (LVADs). However, a subset of patients with late stage biventricular failure or other significant anatomic lesions are not adequately treated by isolated left ventricular mechanical support. Examples of concomitant cardiac pathology that may be better treated by resection and TAH replacement includes: post infarction ventricular septal defect, aortic root aneurysm / dissection, cardiac allograft failure, massive ventricular thrombus, refractory malignant arrhythmias (independent of filling pressures), hypertrophic / restrictive cardiomyopathy, and complex congenital heart disease. Patients often present with cardiogenic shock and multi system organ dysfunction. Excision of both ventricles and orthotopic replacement with a total artificial heart (TAH) is an effective, albeit extreme, therapy for rapid restoration of blood flow and resuscitation. Perioperative management is focused on end organ resuscitation and physical rehabilitation. In addition to the usual concerns of infection, bleeding, and thromboembolism common to all mechanically supported patients, TAH patients face unique risks with regard to renal failure and anemia. Supplementation of the abrupt decrease in brain natriuretic peptide following ventriculectomy appears to have protective renal effects. Anemia following TAH implantation can be profound and persistent. Nonetheless, the anemia is generally well tolerated and transfusion are limited to avoid HLA sensitization. Until recently, TAH patients were confined as inpatients tethered to a 500 lb pneumatic console driver. Recent introduction of a backpack sized portable driver (currently under clinical trial) has enabled patients to be discharged home and even return to work. Despite the profound presentation of these sick patients, there is a 79-87% success in bridge to transplantation.