Resident Chapel hill, North Carolina, United States
Disclosure(s):
Eric Stoutenburg, MD, PhD: No financial relationships to disclose
Background: Right ventricular failure (RVF) is a significant complication of left ventricular assist device (LVAD) implantation associated with increased mortality, with up to 5% of patients requiring right ventricular assist device (RVAD) placement. Optimization of cardiac and pulmonary hemodynamics is critical to mitigate this risk.
Methods: A 67-year old female with end stage heart failure from non-ischemic cardiomyopathy on home milrinone, severe mitral regurgitation, chronic kidney disease and right middle lobe syndrome (RMLS) presented to an outside hospital with worsening dyspnea and lower extremity edema. She was found to be in cardiogenic shock requiring vasopressor support. Right heart catheterization demonstrated post-capillary pulmonary hypertension (mean PA 42 mmHg, PCWP 35 mmHg, PVR 2.1 Woods units) and reduced cardiac index. Echocardiography showed severe LV dysfunction (LVEF 15%, LVIDd 8.7 cm), moderate-severe AI, and preserved RV function. She was admitted to our facility for planned LVAD placement several weeks later. She was hemodynamically optimized on a single inotrope and subsequently underwent uncomplicated surgical implantation of a HM3-LVAD with concomitant bioprosthetic aortic valve replacement.
Outcome: Following LVAD implantation, post-bypass TEE indicated only mild RV dysfunction. Shortly after arrival to the surgical ICU, she developed a series of sudden LVAD low-flow alarms with acute hypotension. Inotropic support was escalated and review of serial chest radiographs noted expansion of her chronic atelectatic right middle lobe with intubation. Bedside echocardiography revealed a moderately sized RV with moderately reduced systolic function. Diuretics were escalated for a CVP target of 8-12, with continuation of inhaled nitric oxide (iNO) and RV protective ventilation ensuring low tidal volumes and minimal PEEP that allowed for collapse of her right middle lobe on follow-up chest radiography. With this strategy, recurrent episodes of low-flow alarms with acute hypotension resolved. Unfortunately, RV hemodynamics declined over the next few days and she required a percutaneous RVAD (ProtekDuo), which allowed for de-escalation of some support. By post-operative day 11 her RVAD had been weaned to 1 LPM. However, elevated CVP (16-18 mmHg), low mixed venous oxygen saturation (SvO2, 28-42%) and a reduced pulmonary artery pulsatility index (PAPi) of 0.82-1.13, prevented attempts at RVAD decannulation. On post-operative day 33, she developed ventricular tachycardia refractory to multiple cardioversions, and her family elected to withdraw care.
Conclusion: This case highlights a rare cause of right ventricular failure after LVAD implantation, likely due to expansion of a chronically atelectatic right middle lobe within a small thoracic cavity causing left atrial compression and impaired LV filling. Recognition of patient-specific anatomy is critical when managing mechanical circulatory support candidates.
