Why have a symposium focused solely on cardiogenic shock?
Everything we do in cardiology stems from our desire to either improve the survival of our patients or improve their quality of life. Over the past several decades, cardiologists have been successful in doing so in many areas, such as acute coronary syndromes (ACS), but have failed to do so when it comes to cardiogenic shock. In fact, temporal trends in shock mortality have not changed significantly over decades, hovering anywhere from thirty-five to fifty percent. It is because of this unacceptable high mortality that we created the Houston Shock Symposium, with an emphasis on three main areas that I think will allow us to have an impact on mortality. First, we need to focus on early recognition of shock patients in the field or in the emergency room. Second, we need to emphasize that it is a systemic problem that begins with the heart, but if not addressed, progresses rapidly to involve every organ in the body. Finally, we need to acknowledge that it is best managed at dedicated shock centers by a multidisciplinary teams that encompass cardiologists, interventionalists, cardiothoracic surgeons, critical care physicians, emergency medical personnel, dedicated nursing staff, perfusionists, and cath lab staff that are well versed in the management and care of shock patients.
Why do patients develop cardiogenic shock?
There are several reasons why patients develop shock. Shock is the final common pathway for multiple different conditions: muscle-related problems including myocardial infarction, myocarditis, or acute ventricular septal defect or wall rupture; valve-related problems such as severe aortic stenosis or acute aortic regurgitation; electrical problems including ventricular tachycardia storm; and, often we see those with chronic heart failure come in with severe acute decompensation and progress to a shock state.
This is the Houston Shock Symposium’s second year. How did it start?
Houston is one the largest U.S. cities, and not only has a well-established legacy of device innovation and shock management, but has had pioneers leading this field for decades. It seemed natural to create this annual symposium in Houston. Chief Biswajit Kar, MD, myself, and my colleagues at the Center for Advanced Heart Failure had a vision of holding an annual, dedicated, and comprehensive shock symposium that brings together national and international experts in this field to meet and share their best practices and experiences, continuing the Houston innovative legacy. I joined the faculty at UTHealth in Houston about 4 years ago, after training at Tufts in Boston, and decided to help fulfill this vision. With the support of UTHealth McGovern Medical School, and with co-providership from the Society for Cardiovascular Angiography and Interventions (SCAI) and the Texas Chapter of the American College of Cardiology (ACC), The Houston Shock Symposium had its inaugural event in April of 2018.
The multidisciplinary aspect sounds central.
Yes. The Houston Shock Symposium hosts experts in different arenas, not just cardiologists. Cardiogenic shock starts as a hemodynamic problem, but it progresses rapidly to multi-organ failure and death. It is not just about the heart, but it is a cardio-renal, cardio-pulmonary, cardio-hepatic, and cardio-metabolic problem. Once multi-organ failure sets in, mortality rates are very high. Thus, it is best managed by a team of experts in different fields of medicine.
Is there a time window with shock like with ST-elevation myocardial infarction (STEMI)?
This is a fantastic question. Since the 1990s, the focus has been mostly on hemodynamics when it comes to shock. A recent meta-analysis by Thiele et al1 of four major clinical trials in shock patients supported with either an intra-aortic balloon pump (IABP) or a TandemHeart (CardiacAssist)/Impella (Abiomed) device demonstrated that higher support devices improved hemodynamics including cardiac output, pulmonary capillary wedge pressure, and blood pressure, but this did not translate into a mortality benefit. The issue goes beyond hemodynamic support. And it is not just about support — when and how you support the patient is key. When is the ideal time to support patients? Similar to STEMI, where patients have a door-to-balloon time of 90 minutes, we need to focus on understanding the ideal door-to-support time in shock patients. This window of opportunity is still not fully known, and is dependent somewhat on the etiology of shock.
How should mechanical circulatory support devices be utilized?
The first question is when should we use support devices? When patients arrive and in shock, the kneejerk reaction is to put them on pressors, because that is the quickest thing to do, but the more pressors you use, the worse the outcome, as demonstrated in multiple studies over the past 20 years. There are different device platforms that should be utilized in shock early but judiciously, whether purely for left ventricular (LV) support with the TandemHeart/Impella family of devices or the IABP; right ventricular (RV) support, such as the Impella RP or the TandemHeart RVAD; biventricular support with a combination of those devices; or utilizing veno-arterial extracorporeal membrane oxygenation (VA-ECMO). Depending on the driver of the shock, the hemodynamics, and the expertise of the team, and the expected patient-device interaction, the device platform choice should be individualized.
How should centers be organized to treat cardiogenic shock?
I think that there should be a hub-and-spoke model, as was discussed in the 2017 American Heart Association scientific statement of cardiogenic shock management.2 A hub-and-spoke model means there is a shock center or several shock centers in a city, to which all the smaller non-shock centers refer. What has worked well for us at UTHealth in Houston is a shock team that is multidisciplinary and available 24/7 to support all our “spoke” hospitals in Houston. We often fly to stabilize patients in shock and bring them back to our main campus at the Medical Center for continued management. Spoke centers should be able to stabilize patients with whatever device platform available in their cath lab, and transfer patients thereafter to the shock center. An open dialogue between the hub and spoke teams is critical to manage patients efficiently.
What would you like to highlight about the second Houston Shock Symposium in March 2019?
The first Houston Shock Symposium was endorsed by the Texas Chapter of the ACC and SCAI. The Shock Symposium is a joint, collaborative effort between UT Health McGovern Medical School and Memorial Hermann Hospital. Our first event had 45 speakers from the U.S. and Europe. The Houston Shock Symposium is a forum that focuses on cultivating cross talks among different disciplines in medicine. This year, we have 50 faculty members: clinical trialists, biomedical engineers, physicians, emergency medical personnel, nurses, and policy makers all in one room to discuss all aspects of shock, and how best we can achieve our three main goals I spoke about earlier. The 2019 Houston Shock Symposium has a dedicated Skills Lab that offers hands-on training on device deployment and troubleshooting scenarios run by selected faculty members of UTHealth McGovern Medical School. Lastly, the Houston Shock Symposium is dedicated to its educational mission: in addition to free registration, we are offering free continued medical and nursing educational credits for our attendees.
Can you talk about the importance of nurses and technologists in treating cardiogenic shock?
This is a very important topic. Team approach to shock management is the key. It starts with emergency medical personnel recognizing shock and activating the cath lab in those with ACS, moving through the chain all the way to the ICU staff. Cath lab staff are often called in to stabilize “crash and burn” patients. The staff needs to attend to a hypotensive patient on several drips, occasionally with active CPR in progress or an unstable rhythm, who need emergent coronary revascularization and mechanical support device deployment. A cohesive staff in the lab working well together, with clear channels of communication between each team member, plays a key role in having a successful outcome.
What research interests you most at the moment?
I am personally interested in device therapies in cardiogenic shock, particularly percutaneous device therapies commonly deployed in the cath lab or bedside. Understanding patient-device interaction in shock is not the same in every patient. We expect increased LV afterload in VA-ECMO, but we don’t see this all the time in clinical practice. We expect to unload the LV with an Impella device, but we sometimes don’t see that occur. Despite animal and preclinical data, the role of unloading in ischemic shock is not well established in large clinical trials nor implemented routinely in clinic practice. I am looking forward to implementing the concept of door-to-unload for patients coming in with STEMI in light of the recent Door-to-Unloading (DTU) clinical data presented by Dr. Navin Kapur3 and to see the impact of unloading in ACS-shock on outcomes. The role of LV unloading in ischemic shock will also be discussed at the Houston Shock Symposium, and I am looking forward to lively discussions on this topic with our faculty and attendees.
1. Thiele H, Jobs A, Ouweneel DM, et al. Percutaneous short-term active mechanical support devices in cardiogenic shock: a systematic review and collaborative meta-analysis of randomized trials. Eur Heart J. 2017 Dec 14; 38(47): 3523-3531. doi: 10.1093/eurheartj/ehx363.
2. van Diepen S, Katz JN, Albert NM, et al; American Heart Association Council on Clinical Cardiology; Council on Cardiovascular and Stroke Nursing; Council on Quality of Care and Outcomes Research; and Mission: Lifeline. Contemporary management of cardiogenic shock: a scientific statement from the American Heart Association. Circulation. 2017 Oct 17;136(16):e232-e268. doi: 10.1161/CIR.0000000000000525.
3. Kapur NK, Alkhouli M, DeMartini T, et al. Unloading the left ventricle before reperfusion in patients with anterior ST-segment elevation myocardial infarction: a pilot study using the Impella CP®. Circulation. 2018 Nov; published ahead of print. doi:10.1161/CIRCULATIONAHA.118.038269.