Temporary Mechanical Circulatory Support During Bariatric Surgery: A Novel Bridge to Durable Left Ventricular Assist Device and Cardiac Transplantation

Case 1

A 30-year-old man was admitted for right heart catheterization due to a decline in left ventricular ejection fraction (LVEF) (50%-55% to 14%) revealed by echocardiogram. Medical history included nonischemic cardiomyopathy, New York Heart Association (NYHA) Class 3b, stage C congestive heart failure (CHF), class IV obesity with body mass index (BMI) of 51.92 kg/m², and type 2 diabetes.

On admission, the patient was hypotensive (82/63 mmHg) with SpO2 96%. Examination was remarkable for ascites, lower extremity edema, and multiple small open sores on the abdomen and calves. He was hyponatremic (Na 129 mEq/mL) with an elevated BNP (541 pg/mL). Right heart catheterization revealed severely elevated filling pressures with marginal cardiac index (CI) (1.55 L/min/m²) and cardiac output (CO) (4.5 L/min).

Post-catheterization, the patient was stabilized with milrinone and furosemide. On hospital day (HD) 4, he became dyspneic and tachycardic with a low-grade fever. A chest computed tomography angiography (CTA) was performed revealing an 8.2 cm pulmonary abscess. Blood cultures were positive for methicillin-sensitive Staphylococcus aureus (MSSA), and vancomycin was initiated. He underwent a repeat heart catheterization on the same day which showed a decrease in CI to 1.13 L/min/m² and CO to 3.2 L/min. The patient was transferred to the cardiothoracic ICU for treatment of concomitant cardiogenic and septic shock. Upon admission, he became progressively hypotensive and required veno-arterial extracorporeal membrane oxygenation (ECMO) with Impella CP placement as a vent. On HD11, he was decannulated from ECMO, and the Impella CP was replaced with an Impella 5.5, which has a longer duration of support. The Impella was set at P8 giving 4.2 liters of flow.

To improve candidacy for left ventricular assist device (LVAD) and eventual cardiac transplantation, he underwent successful laparoscopic sleeve gastrectomy (LSG) on HD26 without any complications. Body mass index at the time was 48.9 kg/m².

After LSG, the patient was supported with Impella 5.5 and decreasing inotropic requirements. On HD50, the Impella was removed and a HeartMate 3 (Abbott, Pleasanton, CA) LVAD was successfully implanted. Follow-up chest CT exhibited complete regression of the pulmonary abscess. On HD68, the patient was discharged. Throughout the hospital course, LVEF remained stable at approximately 10% and increased to 18% 2 months after LSG. Since his discharge, there have been no adverse cardiac events. At 8-month follow-up, BMI has decreased to 42.96 kg/m². Although he remains ineligible for cardiac transplantation due to his BMI, his weight loss thus far after LSG has shown it can be an effective tool in bringing patients closer to meeting transplant criteria.

Case 2

A 64-year-old man with medical history including nonischemic cardiomyopathy, NYHA class IV, stage D CHF (LVEF 15%-20%), implantable cardioverter defibrillator (ICD), atrial fibrillation, pulmonary hypertension, and class III obesity (BMI 41.89 kg/m²) was transferred to our hospital due to severe mitral regurgitation (MR) and cardiogenic shock.

At presentation, his blood pressure was 83/50 mmHg, SpO2 96%, with elevated BNP (360 pg/mL). Right heart catheterization revealed elevated filling pressures with preserved CI (2.43 L/min/m²) and CO (6.1 L/min) on dual inotropes with milrinone and dobutamine. Transesophageal echocardiogram (TEE) revealed severe global hypokinesis with decreased ventricular diastolic compliance, significant biatrial dilation, and severe MR.

Over the subsequent days, he had multiple non-sustained runs of ventricular tachycardia and was transferred to the cardiac ICU. Dobutamine was titrated up over the next week to optimize hemodynamics before escalation to Impella 5.5 implantation on HD16. The Impella was successfully implanted via right axilla and set at P8. On HD26, LSG was successfully performed without complications with the goal of improving candidacy for LVAD placement and eventual cardiac transplantation.

After LSG, the patient continued to be supported on inotropic therapy and Impella. On HD33, the Impella was removed and an LVAD was implanted. After cardiac stabilization, the patient was discharged on HD56. Transthoracic echocardiogram (TTE) before discharge showed LVEF of 10%-15%. Fifteen weeks following surgery, the patient lost 29 lbs and his BMI decreased to 32.39 kg/m². No postoperative complications were noted, and he will continue to be re-revaluated for cardiac transplantation.

Case 3

A 26-year-old man with history of dilated cardiomyopathy, NYHA class III, stage D CHF (LVEF 15%-20%), ICD, and class IV obesity (BMI 52.72 kg/m²) presented to the emergency room with acute CHF exacerbation.

On presentation, his blood pressure was 98/62 mmHg and SpO2 100% with laboratory testing revealing hyponatremia (Na 129 mEq/mL) and an elevated BNP (1170 pg/mL). A right heart catheterization was performed revealing a low CI (1.4 L/min/m²) and CO (3.6 L/min). Transthoracic echocardiogram showed global hypokinesis with restrictive physiology, severe MR, and pulmonary arterial hypertension.

Initially, the patient was hemodynamically stabilized using bumetanide and milrinone. He was concurrently being treated for an acute kidney injury. On HD39, Impella 5.5 was successfully implanted without complications and set at P8. On the following day, LSG was successfully performed. At the time of surgery, the patient’s BMI was 51.41 kg/m².

The patient’s hospital course was later complicated by hepatic and pulmonary abscess formation which resolved with a long course of intravenous meropenem treatment. On HD79, a HeartMate 3 LVAD was successfully implanted. He was discharged on HD110. At follow-up 11 weeks after LSG, he has lost over 65 lbs and BMI has decreased to 42.54 kg/m². He continues to lose weight and is motivated to become eligible for cardiac transplantation.

Discussion

Despite obesity being one of the strongest risk factors for developing HF, many patients with HF are denied cardiac transplantation due to severe obesity. ¹ According to the ISHLT, a BMI of ≤35 kg/m² is recommended prior to listing a patient for cardiac transplantation. ² While bariatric surgery may be a safe and effective bridge to cardiac transplantation in patients with advanced HF and obesity, ³ advanced HF remains a relative contraindication to bariatric surgery due to intraoperative risk. ⁴ Lack of eligibility for both cardiac transplantation (due to excess BMI) and bariatric surgery (due to HF) feeds into a vicious cycle. Cardiac support during bariatric surgery may allow some patients with HF and obesity to overcome this cycle.

Evidence is emerging regarding the successful use of bariatric surgery in patients with HF and LVAD implantation. ³ However, patients with coexisting contraindications to LVAD placement may not have the cardiac capacity to safely undergo bariatric surgery and are thus caught in the same cycle of ineligibility. Off-label use of a catheter-based miniature ventricular assist device (Impella) to support cardiac function during bariatric surgery has not been well studied. Here, we present 3 successful cases of Impella 5.5 use to support cardiac function during bariatric surgery, allowing for BMI reduction and progression toward eligibility for cardiac transplantation. Such intraoperative use may create a new population of patients eligible for cardiac transplantation who would otherwise fail to meet criteria.