Cath Lab Digest

You have a unique perspective on mechanical circulatory support. Can you tell us about your background?

I am an interventional cardiologist with advanced training in heart failure and cardiac transplantation. My background in heart failure certainly influences how I approach patients in the cath lab. On the heart failure service, we think about hemodynamics all the time, because that is how we guide patient therapy. Similarly, as an interventionalist, the root of our practice is founded in a comprehensive appreciation for invasive hemodynamics. Since Tufts has a large cardiac transplant and ventricular assist device (VAD) program, our patient population tends to be people with early or late stage heart failure from various causes, anything from inherited myopathies all the way to acute myocardial infarction (MI). For this reason, we have developed an interdisciplinary interventional/heart failure (IHF) team approach that allows us to implement a gamut of mechanical support devices, both percutaneous and surgical, when necessary. For the past five years, when selecting a percutaneous ventricular support device (Figure 1), we have used a decision-making algorithm that blends interventional criteria, like coronary anatomic risk, clinical characteristics, acute MI and acute coronary syndromes (ACS), and heart failure characteristics such as hemodynamic assessment, New York Heart Association (NYHA) class, and Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) class¹.These multi-disciplinary evaluations often involve our interventionalists, advanced heart failure specialists, and cardiac surgeons.  

My particular expertise focuses on mechanical support devices, cardiac remodeling, and the development of the IHF program at Tufts. The IHF program is a great example of interdisciplinary work leading to better patient care, because decisions often have to be made acutely in the cath lab and having a system in place to rapidly discuss complex patient scenarios, if necessary, is helpful. Everyone, including our technologists and nurses, who are an important part of the IHF team, recognizes that whether we are implanting a mechanical support device, performing a high risk coronary intervention in a patient with advanced heart failure, percutaneously treating an aortic or mitral valve, performing a septal alcohol ablation procedure, or interrogating a patient’s hemodynamic status. We are constantly asking: what is the root cause of their heart failure and what is the best approach to stabilize and improve their quality and quantity of life?

Can you tell us more about the algorithm you use to assess patients for high risk PCI?

For high risk coronary interventions, our algorithm involves four main criteria: 

1. Assessing the patient’s coronary anatomy, thereby laying out realistic expectations of how difficult the procedure may be; 
2. Determining the amount of myocardium at risk in a coronary territory; 
3. Considering other aspects of the patient’s characteristics such as ejection fraction and clinical presentation — is it acute MI, is it ACS, or is it purely an elective percutaneous coronary intervention (PCI)?; 
4. Determining the hemodynamic status of the patient at the time of PCI (perhaps one of the most important criteria).

In most complex PCI cases, we first assess cardiac filling pressures and function with a pulmonary artery (PA) catheter or at minimum, a pigtail left ventricular end diastolic pressure (LVEDP) measurement. If we find that the patient has massively elevated cardiac filling pressures and if it is an elective or semi-elective procedure, we will often opt to diurese the patient, seeking to normalize their hemodynamics as much as possible, before making the myocardium ischemic during a potentially high-risk coronary intervention. For example, if you take a patient who comes in with a LVEDP of 40 who needs to have a PCI done, that makes the procedure considerably higher risk than if the LVEDP is 10, even if each patient has the same ‘high-risk coronary anatomy’. This is because the first effect of ischemia is to increase LVEDP, or cardiac filling pressures, which can lead to congestion, heart failure, cardiogenic shock, etc.