Right ventricle | PulmPEEPs

We are extremely excited to be hosting this episode in collaboration with CardioNerds! We have known Amit and Dan for many years, and they have been huge supporters of Pulm PEEPs, so it is an honor to address a topic we’re all interested in together.

We are joined by experts in the field today to discuss acute, decompensated right ventricle failure in patients with Pulmonary Arterial Hypertension (PAH). This topic can be quite intimidating, so we hope this will serve as a valuable guide for anyone who encounters a patient like this in the ICU.

Meet Our Guests

Leonid “Leon” Mirson is an internal medicine resident at the Johns Hopkins Hospital Osler Medical Residency and an Associate Editor here at Pulm PEEPs. He was born in Ukraine and moved to Philadelphia in early childhood with his family. He received his undergraduate degree from the University of Pittsburgh where he studied biomedical engineering and received his medical degree from the University of Pittsburgh School of Medicine. His current interests include pulmonary and critical care medicine with a focus on pulmonary hypertension as well as medical education. He is a rising PCCM fellow at the University of Pennsylvania.

Bhavya Varma completed her medical school at the University of Pittsburgh, her internal medicine residency at Johns Hopkins, and is a rising Cardiology fellow at NYU. She is interested in medical education and has done work with CardioNerds during her residency.

Mardi Gomberg-Maitland is a Professor of Medicine at George Washington University. She serves as the Medical Director of the Pulmonary Hypertension Program at George Washington Hospital. She completed her medical degree at Albert Einstein College of Medicine, completed her residency at the Weill-Cornell Medical Center, and completed her fellowship in cardiovascular diseases at Mount Sinai Medical Center. Her research focus is on understanding the epidemiology of pulmonary hypertension and the development of novel therapeutics and biomarkers. Dr. Gomberg-Maitland is internationally known for her work, she has had extensive grant funding and has published over 150 articles, abstracts, reviews, and chapters.

Rachel Damico is a pulmonologist and an Associate Professor of Medicine at Johns Hopkins Hospital, where she is also the Associate Director of the physician-scientist training program. Dr. Damico received her medical degree and doctoral degree in Molecular and Cellular biology from the University of Pennsylvania. She completed her residency in the Osler Internal Medicine training program and continued on as a PCCM fellow at Johns Hopkins. She has quickly achieved an international reputation in the field of pulmonary vascular biology and both basic and translational research, as well as clinical excellence, in Pulmonary Arterial Hypertension.

Patient Presentation

A 21-year-old woman with a past medical history notable for congenital heart disease (primum ASD and sinus venosus with multiple surgeries) complicated by severe PAH on home oxygen, sildenafil, ambrisentan, and subcutaneous treprostinil is presenting with palpitations, chest pain, and syncope. She presented as a transfer from an outside ED where she arrived in an unknown tachyarrhythmia and had undergone DCCV due to tachycardia into the 200s and hypotension. On arrival at our hospital, she denied SOB but did endorse nausea, leg swelling, and poor medication adherence. Her initial vitals were notable for a BP of 80/50, HR 110, RR 25, and saturating 91% on 5L O2. On exam, she was uncomfortable appearing but mentating well. She had cool extremities with 1-2+ LE edema. Her JVP was 15cm H2O. She has an RV Heave and 2/6 systolic murmur. Her lungs were clear bilaterally. Her labs were notable for Cr 2.0, an anion gap metabolic acidosis (HCO3 = 11), elevated lactate (4.1), elevated troponin to 14, and a pro-BNP of ~5000. Her CBC was unremarkable. Her EKG demonstrated 2:1 atrial flutter at a rate of 130.

Key Learning Points

Diagnosing RV failure in patients with PH:

RV dysfunction and RV failure are two separate entities. RV dysfunction can be measured on echocardiography, but RV failure can be thought of as a clinical syndrome where there is evidence of RV dysfunction and elevated right sided filling pressures.

RV failure is a spectrum and can present with a range of manifestations from evidence of R sided volume overload and markers of organ dysfunction, all the way to frank cardiogenic shock. Most patients with RV failure are not in overt shock.

One of the first signs of impending shock in patients with RV failure is the development of new or worsening hypoxemia. Patients with decompensated RV failure approaching shock often do not present with symptoms classic for LV low flow state. Instead, hypoxia 2/2 VQ mismatching may be the first sign and they can be otherwise well appearing. Particularly because patients with PH tend to be younger, they can often appear compensated until they rapidly decompensate.

Causes of decompensation for patients with RV dysfunction and PH:

Iatrogenesis (inadvertent cessation of pulmonary vasodilators by providers, surgery if providers are not familiar with risks of anesthesia), non-adherence to pulmonary vasodilators (either due to affordability issues or other reasons), infections, arrhythmias (particularly atrial arrhythmias), and progression of underlying disease.

Patients with atrial arrhythmias (atrial flutter or atrial fibrillation) and pulmonary hypertension do not tolerate the loss of the atrial kick well as it contributes a significant amount to their RV filling and impacts their cardiac output. It is often difficult to determine if the atrial arrhythmia is a cause or effect of decompensated RV failure, but its presence is associated with a worse prognosis. Efforts should be made to re-establish normal sinus rhythm in patients with decompensated RV failure and atrial arrhythmias.

A patient’s home PH medications should never be stopped for any reason upon admission unless on the basis of recommendations by a pulmonary hypertension provider as this is often a cause of decompensation inpatient

Interpreting findings on echocardiogram:

Echo is a useful screening tool. When interpreting evidence of RV dysfunction, it is important to look at the global picture and not just one measurement.

RVSP, though commonly reported, may be of limited value when evaluating for decompensation. It’s a function of blood pressure, heart rate, and cardiac output. RVSP may even decline as shock worsens.

TAPSE is useful as a marker of RV dysfunction if it is reduced, but it is difficult to follow over time and only gives information about cardiac function around the annulus; it may be normal even when apical RV function is depressed. RV fractional area of change may be more useful for global RV function. It is important to pay attention to the RV size overall, the degree of TR, and the presence of effusion all of which are associated with RV dysfunction.

Tips regarding the interpretation of invasive hemodynamics:

Cardiac output by thermodilution is the standard way to calculate PVR. Despite the degree of TR that is typically present, it is thought to be a better representation of cardiac output than the estimated Fick calculation.

Our experts agree that routine monitoring of invasive hemodynamics for acute decompensated RV failure is likely not helpful and has significant risks. A good external volume exam or CVP off a central venous catheter + central venous saturation will likely be all you need to navigate a patient with shock secondary to RV failure. A right heart catheterization (should be only done under fluoroscopy for patients with large RVs) may be helpful if the etiology of shock is unclear.

Management of decompensated RV failure in patients with pulmonary hypertension

Managing preload is of utmost importance, perhaps the most important tenant of management of decompensated RV failure. The overwhelming majority of patients with PH and decompensation are volume overloaded, it is exceptionally rare that someone would be dry. Furthermore, the myth that the RV is “preload responsive” is only true in the setting of acute RV injury (eg. RV infarction) and not so in patients with acute on chronic RV dysfunction. It is important to optimize preload in someone in decompensated RV failure and it is safe to do this more rapidly than traditionally taught. Exact goals varied between our experts, but anywhere from 2-4L net negative per day is reasonable especially if the patient is hemodynamically tolerating the fluid removal. If the patient is not responding to diuretics, hemodialysis with ultrafiltration may be necessary to optimize the patient.

Afterload is the next tenant of management. Optimizing the following parameters will reduce the patient’s pulmonary vascular resistance and reduce afterload to the right ventricle.

— Avoiding hypoxic pulmonary vasoconstriction, liberalize the patient’s O2 goal

— Avoid permissive hypercapnia and academia in this patient population

— Do not withhold a patient’s pulmonary vasodilator until discussion with the PH team. If stopped inadvertently, restart this medication immediately. For patients with malfunctioning pumps, there is a phone number on the back that you can call for rapid troubleshooting. Sildanefil can be given IV if a patient is NPO.

— Inhaled nitric oxide can improve oxygenation and reduce afterload

— Intubation and mechanical ventilation greatly increase PVR and are poorly tolerated. Exacting care must be taken to titrate PEEP and tidal volume, and avoid intubation when possible.

— Starting a new systemic pulmonary vasodilator in decompensated RV failure may be considered under close guidance from the pulmonary hypertension team

Management of atrial arrhythmias:

As above, patients with severe pulmonary hypertension do not tolerate loss of sinus rhythm well. If they are decompensated, every effort should be made to re-establish normal sinus rhythm.

Management of RV perfusion:

Unlike the LV, the RV is perfused during BOTH systole and diastole. Maintaining effective coronary perfusion to the RV is essential in RV failure. For this reason, the systemic systolic pressure (as well as the mean arterial pressure) should be kept high enough to ensure that the RV is able to perfuse. There is no great body of evidence as to which pressor works best. Norepinephrine, vasopressin, and even phenylephrine are all reasonable choices to maintain appropriate perfusing blood pressure.

Inotropy:

Patients in shock and RV failure do not always require inotropes, but if they do it’s often a sign of a grim prognosis. Either dobutamine or milrinone is reasonable, but the negative effects of these drugs (arrhythmias, tachycardia, and systemic hypotension) may limit their uses.

Mechanical circulatory support:

Limited options are available. Balloon pumps and Impella devices have limited roles except in expert centers, and ECMO remains the standard of care. ECMO (either V-V or V-A) may have utility as a bridge to recovery if a reversible cause is identified, or a bridge to transplant if the patient is on the transplant list.

Goals of care:

The prognosis of a patient admitted to the ICU with acute on chronic decompensated RV failure is guarded, with very high mortality rates even if not in shock

It is important for the patient’s longitudinal pulmonary hypertension provider to discuss the prognosis and goals of care ahead of time but this is not always possible. If they are admitted, early discussions regarding code status and prognosis are essential. It may be helpful to bring in the patient’s longitudinal pulmonary hypertension doctor into these discussions if possible.

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