One-year survival in recipients older than 50 bridged to heart transplant with Impella 5.5 via axillary approach

Comparison of Intraoperative Blood Product Use During Heart Transplantation in Patients Bridged with Impella 5.5 versus Durable Left Ventricular Assist Devices

OBJECTIVE

To determine if the intraoperative transfusion requirements differ based on the mechanical circulatory device used as a bridge to heart transplantation.

DESIGN

A single-center retrospective analysis of intraoperative transfusion requirements in all patients undergoing heart or heart/kidney transplantation between November 2018 and July 2021 who were bridged with a temporary (Impella 5.5) or durable left ventricular assist device (LVAD).

SETTING

A tertiary care hospital.

PARTICIPANTS

Forty-three adult patients bridged to heart or heart/kidney transplantation with a temporary or durable LVAD between 2018 and 2021 INTERVENTIONS: Recording of baseline characteristics and intraoperative transfusion requirements, including packed red blood cells, fresh frozen plasma, cryoprecipitate, autologous blood salvage, and platelets. The difference in cardiopulmonary bypass times, intensive care unit length of stay, and the vasoactive inotrope score following transplantation were also recorded.

MEASUREMENTS AND MAIN RESULTS

The primary outcome was the volume of blood products transfused intraoperatively. Patients who underwent bridge to transplantation using the Impella 5.5 had statistically significant lower median transfusions of cryoprecipitate (155 mL versus 200 mL, p = 0.015), autologous blood salvage (675 mL versus 1,125 mL, p ≤ 0.01), and platelets (412 mL versus 675 mL, p ≤ 0.01). Additionally, there was a trend toward lower transfusion of intraoperative packed red blood cells (4.5 units versus 6.5 units, p = 0.29) and fresh frozen plasma (675 mL versus 800 mL, p = 0.11), but these were not statistically significant.

CONCLUSIONS

The results suggest a reduction in certain intraoperative transfusion requirements in patients undergoing heart transplantation bridged with the Impella 5.5 versus durable left ventricular assist device.

Impella 5.5 Bridge to Heart Transplant: An Institutional Series and a Closer Look at Device Removal Technique

Limited donor organ availability often necessitates mechanical circulatory support, and recently the Impella 5.5, as a bridge to heart transplant. Of 175 Impella 5.5-supported patients at our institution, 45 underwent transplantation in the largest series to date, for whom we analyzed outcomes. Two methods of complete device explant were evaluated: central Impella transection and removal via axillary graft. Median Impella days were 25 (16-41); median waitlist days were 21 (9-37). Eighty-nine percent (40/45) of patients had device placement via right axillary artery. Seventy-six percent (34/45) underwent central transection for device removal. Four patients (8.9%) required short-term venoarterial extracorporeal membranous oxygenation (VA ECMO) postoperatively for primary graft dysfunction (PGD). Two patients (4.4%) suffered postoperative stroke. Five patients (11.1%) required new RRT postoperatively. One patient (2.2%) returned to the operating room (OR) for axillary graft bleeding. A higher chance of procedural complications was found with the axillary removal technique ( p = 0.014). Median intensive care unit (ICU) days, length of stay (LOS), and postoperative days to discharge were 46 (35-63), 59 (49-80), and 18 (15-24), respectively. Ninety-eight percent (44/45) survived to discharge. Thirty-day survival was 95.6% (43/45), with 1 year survival at 90.3% (28/31). Eighty-eight percent (37/42) remain without rejection. In our institutional experience, Impella 5.5 is a safe and reliable bridge to transplant.

Case Report: Unmasking sustainable left ventricular recovery in chronic heart failure with axillary temporary mechanical circulatory support

Background

Mechanical circulatory support (MCS), temporary or durable, is essential in patients with acute heart failure presenting in cardiogenic shock (CS). MCS is fundamental in patients with advanced heart failure when used as a bridge to decision, transplant or left ventricular recovery. Limited data on acute-on-chronic heart failure (HF) patients exists in the era of axillary mechanical circulatory support with the Impella 5.5. We describe a case of chronic ischemic cardiomyopathy, HF-CS, in a patient who underwent Impella placement, medical optimization, and explant, now with sustained normalization in ejection fraction.

Case summary

A Caucasian female in her 50 s was referred to our center for evaluation for advanced therapies, including transplantation or durable left ventricular assist device placement. Her initial ejection fraction was 30% with comorbidities including multivessel coronary artery disease revascularized with 3 vessel bypass grafting ten years prior, type 2 diabetes (A1c 8.6%), and peripheral vascular disease. During her evaluation, she had acute decompensation leading to cardiogenic shock and required hospitalization with inotrope initiation, which was unable to be weaned. She was approved for organ transplant and listed; however, she required escalation of support and eventual placement of right axillary Impella 5.5. While on Impella support, her vasoactive needs reduced, and she was found to have left ventricular recovery and tolerated the initiation of guideline medical therapy. After three weeks of support, the Impella was weaned and explanted, and the patient was discharged. She remains stable with a sustained ejection fraction of greater than 50% with NYHA class 1 functional status at follow-up. One year later, the patient showed sustained myocardial recovery with guideline-directed medical therapy (GDMT).

Conclusion

Our case highlights a unique approach in patients with long-standing (>5 years) heart failure who may benefit from early consideration for axillary support and concomitant optimization with guideline-directed medical therapy to assess for explant and native heart recovery.

Impella 5.5 in left ventricular noncompaction syndrome as bridge to heart transplant

Background

Left ventricular non-compaction syndrome (LVNC) is an uncommon congenital disease characterized by prominent trabeculations and deep inter-trabecular recesses of the left ventricle wall. We present the first reported case of Impella 5.5 use in LVNC as a bridge to transplant in a highly sensitized patient.

Methods

A 50-year-old female with a family history of sudden cardiac death, LVNC cardiomyopathy associated with TPM1 gene mutation, and recurrent hospitalizations due to heart failure was listed for heart transplantation. She had severely reduced systolic function (EF 20%) and high panel reactive antibodies (PRA). She was admitted for desensitization therapy. Hospitalized, she escalated to Dobutamine and Milrinone due to progressive shock. Impella 5.5 was inserted, and inotropes were reduced as her condition steadied. She tolerated desensitization and eventually underwent heart transplantation after 120 days of continuous Impella 5.5 support without developing hemolysis or pump thrombosis.

Results

Post-transplant she was found to have concern for left sided stroke symtpoms but completely recovered and remians stable on follow up at 6 months. Due to the lack of prospective trials with large cohorts, managing patients with LVNC and cardiogenic shock is challenging. Novel approaches to complex patients with both Impella 5.5 support and desensitization therapies should be considered in the appropriate setting.

Conclusion

Our case highlights the use of mechanical circulatory support in the management of cardiogenic shock within a small left ventricluar cavity in a sensitized patient. This approach should be considered in high-risk patients in whom durable left ventricular assist therapy is not feasible.

The Year in Cardiothoracic and Vascular Anesthesia: Selected Highlights From 2023

This special article is the 16th in an annual series for the Journal of Cardiothoracic and Vascular Anesthesia. The authors thank the editor-in-chief, Dr. Kaplan, and the editorial board for the opportunity to continue this series, namely the research highlights of the past year in the specialty of cardiothoracic and vascular anesthesiology. The major themes selected for 2023 are outlined in this introduction, and each highlight is reviewed in detail in the main article. The literature highlights in the specialty for 2023 begin with an update on perioperative rehabilitation in cardiothoracic surgery, with a focus on novel methods to best assess patients in the preoperative and postoperative periods, and the impact of rehabilitation on outcomes. The second major theme is focused on cardiac surgery, with the authors discussing new insights into inhaled pulmonary vasodilators, coronary revascularization surgery, and discussion of causes of coronary graft failure after surgery. The third theme is focused on cardiothoracic transplantation, with discussions focusing on bridge-to-transplantation strategies. The fourth theme is focused on mechanical circulatory support, with discussions focusing on both temporary and durable support. The fifth and final theme is an update on medical cardiology, with a focus on outcomes of invasive approaches to heart disease. The themes selected for this article are only a few of the diverse advances in the specialty during 2023. These highlights will inform the reader of key updates on various topics, leading to improved perioperative outcomes for patients with cardiothoracic and vascular disease.

Revisiting Pulmonary Hypertension in the Era of Temporary Mechanical Circulatory Support - Literature Review and Case-Based Discussion

BACKGROUND

Pulmonary arterial hypertension (PAH) is characterized by persistently increased pressure in the pulmonary arteries. New defining criteria for the different hemodynamic types of pulmonary hypertension (PH) that occur with left heart disease have been proposed by the task force on PH. After consideration of the changes in the general definition of PH in left heart disease, the proposed hemodynamic definition was: (1) isolated postcapillary PH: pulmonary artery wedge pressure >15 mm Hg and mean pulmonary arterial pressure (mPAP) >20 mm Hg and pulmonary vascular resistance (PVR) <3 Woods units (WU); and (2) combined post- and precapillary PH: pulmonary artery wedge pressure >15 mm Hg, mPAP >20 mm Hg, and PVR ≥3 WU. Secondary PH is initially reversible, but eventually, it can become fixed because of the remodeling process of the pulmonary vascular system. Limitations in defining both the time for and amount of reversibility lack clarity. We discuss a case of PH as a framework to better understand these key principles in addressing patients' candidacy for heart or heart-lung transplantation.

METHODS

We performed a literature search for all available contemporary data with the following terms: "pulmonary hypertension," "reversal," "Impella 5.5," "temporary mechanical support," and "LVAD" using the National Library of Medicine - PubMed and PubMed Central between 2019 and 2023. A total of 14 published papers were found with these search. From these, 3 addressed the issue of PH and reversibility in the setting of LHD after durable LVAD placement. No papers were found using Impella 5.5 and PH during this timeframe. Given the paucity of data in the field regarding temporary mechanical circulatory support and pulmonary hypertension, we present a case-based discussion to guide the reader in understanding the potential impact of this method in patients with WHO Class 2 Pulmonary hypertension.

CASE

A 49-year-old woman with a medical history of acute on chronic biventricular systolic and diastolic heart failure, American College of Cardiology stage D, Stevenson profile C, New York Heart Association class IV (ejection fraction 18%) secondary to nonischemic cardiomyopathy after cardiac resynchronization therapy, pulmonary hypertension, bilateral deep vein thrombosis, and segmental pulmonary embolism presented for heart transplant evaluation. Her cardiac output and central hemodynamics were measured, and she was found to have a pulmonary artery (PA) pressure of 78/38 with a mean PA pressure of 51, pulmonary capillary wedge pressure (PCWP) 30, transpulmonary pressure gradient (TPG) 21, thermodilution cardiac output (CO) 3.35 L/min, and cardiac input (CI) 1.75 L/min/m2. Her PVR was 6.2 WU. Provocative pharmacologic testing for reversibility of PH was performed using sodium nitroprusside, which resulted in a blood pressure of 83/57 (92), heart rate 92/min, and PA pressure of 71/31, with a mean PA pressure of 44 PCWP 22, TPG 22, CO 4.8 L/min, and CI of 2.48 L/min/m2 with a PVR of 4.5 WU. Following this, the patient underwent Impella 5.5 placement through the right axillary artery to optimize afterload reduction and improve end-organ perfusion. Post-Impella hemodynamics on milrinone 0.5 mcg/kg/min demonstrated the following: blood pressure 90/66 (74), heart rate 53/min, and PA pressure of 56/29, with a mean PA pressure of 38, PCWP 24, TPG 14, CO 6 L/min, and CI of 2.9 L/min/m2 with a PVR of 2.3 WU.

CONCLUSION

Left ventricular assist device support with Impella 5.5 is associated with a reduction in mPAP and PVR over weeks to months and thus plays a crucial role as a bridge to transplant. Our case and this review highlights the characteristics of PH resulting from heart failure with reduced ejection fraction and discusses the important clinical issues related to the treatment of these patients. We have shown that left ventricular assist device therapy with Impella 5.5 can effectively reduce left-sided filling pressures and lead to PH improvement. We demonstrate the potential benefits of Impella 5.5 in the management of patients with WHO 2 PH and cardiogenic shock with impaired hemodynamics.

Axillary mechanical circulatory support improves renal function prior to heart transplantation in patients with chronic kidney disease

Impaired kidney function is often associated with acute decompensation of chronic heart failure and portends a poor prognosis. Unfortunately, current data have demonstrated worse survival in patients with acute kidney injury than in patients with chronic kidney disease during durable LVAD placement as bridge therapy. Furthermore, end-stage heart failure patients undergoing combined heart-kidney transplantation have poorer short- and long-term survival than heart transplants alone. We evaluated the kidney function recovery in our heart failure population awaiting heart transplantation at our institution, supported by temporary Mechanical Circulatory Support (tMCS) with Impella 5.5. The protocol (#22004000) was approved by the Mayo Clinic institutional review board, after which we performed a retrospective review of all patients with acute on chronic heart failure and kidney disease in patients considered for only heart and kidney combined organ transplant and supported by tMCS between January 2020 and February 2021. Hemodynamic and kidney function trends were recorded and analyzed before and after tMCS placement and transplantation. After placement of tMCS, we observed a trend towards improvement in creatinine, Fick cardiac index, mixed venous saturation, and glomerular filtration rate (GFR), which persisted through transplantation and discharge. The average duration of support with tMCS was 16.5 days before organ transplantation. The median pre-tMCS creatinine was 2.1 mg/dL (IQR 1.75-2.3). Median hematocrit at the time of tMCS placement was 32% (IQR 32-34), and the median estimated glomerular filtration rate was 34 mL/min/BSA (34-40). The median GFR improved to 44 mL/min/BSA (IQR 45-51), and serum creatinine improved to 1.5 mg/dL (1.5-1.8) after tMCS. Median discharge creatinine was 1.1 mg/dL (1.19-1.25) with a GFR of 72 (65-74). None of these six patients supported with tMCS required renal replacement therapy after heart transplantation. Early adoption of Impella 5.5 in this patient population resulted in renal recovery without needing renal replacement therapies or dual organ transplantation and should be further evaluated.