This episode discusses cardiogenic shock due to valvular heart disease. Join Dr. Pranoti Hiremath, interventional cardiology fellow, Johns Hopkins Medicine; Dr. Karan Desai, cardiology fellow, University of Maryland; Dr. Yoav Karpenshif, chief cardiology fellow, University of Pennsylvania; and Dr. Amit Goyal, CardioNerds Co-Founder, for an interview with Dr. Paul Cremer, associate director of the Cardiac Intensive Care Unit and Cardiovascular Fellowship at the Cleveland Clinic, covering an overview of valvular shock, including nuances in diagnosis, differing presentations, and how physical exam, multi-modality imaging, and invasive hemodynamics can inform management.
Pearls and Quotes
1. 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.
2. 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.
3. 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.
4. Echocardiography is critical to understand the etiology and severity of valvular shock, and invasive hemodynamics are often needed to guide medical and mechanical interventions.
5. 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
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 extracorporeal 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.
o 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.
o 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.
o 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.
o Percutaneous balloon valvuloplasty of the aortic valve may be utilized as a bridge to definitive therapy in select patients
• In 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.