Show notes
In this episode we discuss cardiogenic shock due to valvular heart disease. Join Dr. Pranoti Hiremath (Interventional cardiology fellow, Johns Hopkins), Dr. Karan Desai (CN Critical Care Series Co-Chair, Cardiology fellow, University of Maryland), Dr. Yoav Karpenshif (CN Critical Care Series Co-Chair, Chief cardiology fellow, University of Pennsylvania), and Amit Goyal (CardioNerds Co-Founder) as they interview Dr. Paul Cremer (Associate Director of the Cardiac Intensive Care Unit and Associate Director of the Cardiovascular Fellowship at the Cleveland Clinic) in this broad overview of valvular shock. We discuss the nuances in diagnosis, differing presentations and how physical exam, multi-modality imaging, and invasive hemodynamics can inform management. Audio editing by Dr. Gurleen Kaur (Director of the CardioNerds Internship and CardioNerds Academy Fellow).
The CardioNerds Cardiac Critical Care Series is a multi-institutional collaboration made possible by contributions of stellar fellow leads and expert faculty from several programs, led by series co-chairs, Dr. Mark Belkin, Dr. Eunice Dugan, Dr. Karan Desai, and Dr. Yoav Karpenshif.
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Pearls and Quotes - Cardiogenic Shock and Valvular Heart Disease
Shock due to valve disease is the result of a structural abnormality that may be temporized with medical therapy and circulatory support devices. However, it is ultimately best treated with a structural solution in the form of either percutaneous valvular therapies or cardiac surgery.When treating a patient with cardiogenic shock with normal or hyperdynamic ventricular function, we should keep a high index of suspicion for valvular disease. The cardiac output may be reduced due to a stenotic lesion “blocking” forward flow or regurgitant lesion causing backward flow.Acute mitral and aortic regurgitation will typically not manifest as a loud murmur on physical exam. The combination of hypotension and rapid flow of regurgitant blood on an “unprepared” cardiac chamber results in rapid equalization of chamber pressures, shortening the intensity and duration of the murmur. On transthoracic echocardiogram, for instance with acute MR, color Doppler may not show a large turbulent jet, and thus the MR may be underestimated or not appreciated at all.Echocardiography is critical to understand the etiology and severity of valvular shock, and invasive hemodynamics are often needed to guide medical and mechanical interventions.In multi-valve disease with severe aortic stenosis and functional mitral regurgitation, we typically treat the aortic stenosis first, since the mitral regurgitation may improve from the reduction in afterload associated with treating aortic stenosis.
Show notes - Cardiogenic Shock and Valvular Heart Disease
1. Shock due to valve disease arises due to a structural problem that may be temporized with medical therapy and circulatory support devices, but is ultimately best treated with a structural solution in the form of either percutaneous valvular therapies or cardiac surgery.
Stabilizing therapies for acute mitral regurgitation include afterload reduction with vasodilators, diuresis as needed to reduce pulmonary edema, and mechanical circulatory support including intra-aortic balloon pumps.Therapies for acute aortic regurgitation are typically more limited and include vasopressors such as epinephrine. Bradycardia should be avoided with agents such as dobutamine or temporary pacing to reduce time in diastole. Temporary mechanical circulatory support options are limited in the setting of acute AR, though case reports of techniques such as LAVA ECMO (left atrial venoarterial extracorpeal membrane oxygenation) as a bridge to definitive therapy have been reported.There are several factors to consider in patients with aortic stenosis and cardiogenic shock.In some patients with aortic stenosis and LV dysfunction, the shock is a result of LV pressure overload potentially leading to congestion, the high afterload introduced on the LV by the stenotic aortic valve, and increased systemic vascular resistance (compensatory for the failing LV). In these patients, acute vasodilators (specifically nitroprusside) can relieve the additive afterload on the LV imposed by increased SVR as a bridge to definitive therapy.In other patients with severe AS, the LV faces high afterload at the level of the aortic valve but the SVR is relatively low (as well as the pressures in the aortic root which can reduce coronary perfusion), and thus these patients may require a pure alpha agonist (e.g., phenylephrine) to reduce the afterload mismatch and reduce myocardial ischemia.Furthermore, when patients have high LV filling pressures, they are reliant on longer diastole times and an atrial kick to promote LV filling and thus rapid atrial fibrillation can be highly detrimental. In both phenotypes, mechanical circulatory support may be needed as a bridge to valve surgery or TAVR.Percutaneous balloon valvuloplasty of the aortic valve may be utilized as a bridge to definitive therapy in select patientsIn scenarios of valvular disease and cardiogenic shock, right heart catheterization can be helpful to guide and titrate medical therapy and inform decisions to escalate to mechanical circulatory support.Percutaneous therapies (e.g., TAVR or Transcatheter Edge to Edge Repair with MitraClip) are increasingly being utilized as a “primary” therapy on a case by case basis for patients in cardiogenic shock with valvular disease. More data is needed to inform patient phenotypes who would benefit from such a strategy without futility.
2. What is the differential diagnosis for cardiogenic shock with normal or hyperdynamic left ventricular function?
One framework to approach cardiogenic shock with normal or hyperdynamic left systolic function is to consider (1) pericardial failure with constriction or tamponade; (2) myocardial failure with severe restrictive disease (3) electrical failure with new arrhythmia, or (4) valvular failure.In this scenario, we should have a high index of suspicion for valvular disease. The cardiac output may be reduced due to a stenotic lesion blocking forward flow or regurgitant lesion causing backward flow.
3. If I don’t hear a significant murmur on examination, does that rule out an acute regurgitant valvular disease as a cause of shock?
Acute mitral and aortic regurgitation may not manifest as a loud murmur on physical exam. In severe, acute AR, a murmur may not be audible if the diastolic pressure in the LV and aorta equilibrate quickly. Similarly, in acute, severe MR, there can be a rapid rise in LA Pressure reducing the driving pressure across the mitral valve.On transthoracic echocardiogram, the same pathophysiology can explain why acute regurgitant lesions may not be readily apparent. For instance, with acute MR, color Doppler may not show a large turbulent jet, and thus the MR may be underestimated or not appreciated at all. In patients with sudden hemodynamic instability after myocardial infarction with hyperdynamic LV function by TTE, for instance, and no other cause for deterioration, TEE can be helpful in evaluating for Acute MR due to papillary muscle or chordal rupture.
4. Echocardiography and guidance with right heart catheterization is helpful to understand the etiology and severity of valvular shock.
Echocardiography can help determine whether valve dysfunction is primary (e.g. leaflet perforation due to endocarditis) versus secondary (e.g. dilated left ventricle leading to functional mitral regurgitation), as well as provide clues to the chronicity of valve disease.A right heart catheterization can help inform whether valvular disease is the primary insult or if other factors are contributing, inform an initial management strategy (e.g., medical therapies alone vs. mechanical circulatory support), and assess response to therapy.
5. In multi-valve disease, what is the best way to differentiate which lesion is the culprit?
These scenarios are not uncommon and require clinicians to use a multi-modal approach, from patient history, exam, echocardiography, other imaging modalities, and invasive hemodynamics. Identifying the “primary” lesion can still be difficult even after multiple data points.Empiric therapy and assessment of subsequent hemodynamic response may be one way to practically approach multi-valve disease.One scenario covered on the episode was patients with severe aortic stenosis and severe mitral regurgitation. The MR in this scenario may be partly functional due to high LV systolic pressures and may improve with intervention on the aortic valve. Thus, one approach would be to treat AS and evaluate if the MR improves.
References - Cardiogenic Shock and Valvular Heart Disease
Erlebach M, Lange R. Multivalvular Disease: Percutaneous Management in 2019 and Beyond. Interv Cardiol. 2019;14(3):142-146. Published 2019 Nov 18. doi:10.15420/icr.2019.13.R1
Khot UN, Novaro GM, Popović ZB, Mills RM, Thomas JD, Tuzcu EM, Hammer D, Nissen SE, Francis GS. Nitroprusside in critically ill patients with left ventricular dysfunction and aortic stenosis. N Engl J Med. 2003 May 1;348(18):1756-63. doi: 10.1056/NEJMoa022021. PMID: 12724481.
Otto CM, Nishimura RA, Bonow RO, et al. 2020 ACC/AHA Guideline for the Management of Patients With Valvular Heart Disease: Executive Summary: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines [published correction appears in Circulation. 2021 Feb 2;143(5):e228] [published correction appears in Circulation. 2021 Mar 9;143(10):e784]. Circulation.