IAGS Discussion – Supporting Patients in Shock

The High Mortality Among Patients in Cardiogenic Shock “LV or RV Infarcts:” What Have We Learned and Have We Made a Difference? In this symposium, we will revisit the treatment of cardiogenic shock complicating acute myocardial infarction with both right ventricular and left ventricular problems. In patients who do not survive cardiogenic shock complicating acute myocardial infarctions, a number of well known univariate predictors have stood up over time: Age greater than 60 years, prior angioplasty, the use of intraortic balloon pumps (trends) and early revascularization. (Edep and Brown Am J Cardiol 2000;85:1185–1188). Right ventricular infarction is a common cause of cardiogenic shock among patients with ST segment elevation myocardial infarction. It accounted for 20% of cases involving shock in the GUSTO I trial. These problems comprised the volume sensitive state that contrasts with the pressure sensitive state characteristic of predominantly left ventricular infarcts. (Topol et al. Lancet 2000;356:749–755). We will discuss the revascularization techniques in cardiogenic shock including angioplasty, stents, coronary artery bypass, (on and off the pump), and selective valve or ventricular septal defect repair. Mortality has declined for patients greater than 65 years of age complicated by cardiogenic shock. We feel that this has occurred in the setting of broader use of early revascularization and adjuncts to medical therapy for this high risk population. Intraortic balloon pump use in cardiogenic shock has shown survival advantage, but there are no good randomized trials and the effect of additional factors is not clear, including selection timing, direct revascularization strategies, thrombolytics, etc. The SHOCK trial has given us a great deal of information about the importance of our approach to patient with shock in acute myocardial infarction. We will discuss these in some detail and review the data from the SHOCK trial. (Barrow, Chow in Am Heart J 2000;141:133–139 and Webb, Hochman et al.Am Heart J 2001;141:964–970). The trends in outcomes are that early revascularization may be associated with a significant reduction in in-hospital mortality compared to the patients that are treated less aggressively. The wide spread use of intracoronary stents and antiplatelet agents appear to help with the early hazards of shock complicating acute myocardial infarction. Our recommendations in treatment of these patients will be reviewed and supported by the discussion from the panel. We are guardedly optimistic about improvement and the outcomes of this critically ill population. Paul A. Overlie, M.D., F.A.C.C., F.A.C.P. Discussion Moderator: Jim Zidar Panel Members: Luis de la Fuente; Gian Feltrin; Alfredo Rodriguez; Fayaz Shawl Fayaz Shawl:Since we are more aggressive early on, the number of shock cases has diminished. In terms of our approach in treating cardiogenic shock cases, it really depends on the patient’s overall status. Most cardiogenic shock cases I see today are not as extreme as in the past because they present earlier treatment. For patients in cardiogenic shock — I mean true shock which is associated with low blood pressure and signs of hypoperfusion — we routinely place a balloon pump. I and others have reported on the use of IABP, which is probably the most common type of support used. The number of patients requiring CPS is very small — only two or three cases a year at my hospital. These cases involve patients who are in full-blown shock, and the majority of them have multi-vessel coronary disease. As we have seen from Paul Overlie’s work and that of others, if we just perform infarct-related vessel intervention on the multi-vessel disease patients, there is a much higher incidence of mortality. At our lab, if we find that the other two vessels have very tight lesions, especially with a reduction of TIMI flow, we will not only treat the infarct-related vessel, but will intervene on the other two lesions as well, producing much better outcomes. In summary, the number of shock patients is fairly small, and the majority of them are successfully treated with intervention and sometimes balloon pump therapy. A very small percentage of patients require more support such as CPS. James P. Zidar: Are there any comments from our Argentine colleagues? Dr. de la Fuente? Alfredo Rodriguez: In terms of performing intervention on patients in cardiogenic shock, we see some issues that need resolving. First, patients need early intervention. In the SHOCK trial, for instance, when we evaluated the results, the time period from diagnosis of shock, to randomization, to opening the artery, was too long. The use of intra-aortic balloon pumps is another important issue, as is the use of glycoprotein IIb/IIIa agents. One of the major problems with the acute myocardial infarction trials, ADMIRAL and CADILLAC, which tested the use of IIb/IIIa glycoproteins in the acute MI site, is the selection bias. Cardiogenic shock is one of the exclusion criteria in these trials. Thus, with these trials, we cannot evaluate the role of IIb/IIIa glycoprotein agents in treating cardiogenic shock. Perhaps we need a more realistic trial that includes patients in a real world presentation of acute myocardial infarction to evaluate IIb/IIIa glycoproteins. We are currently involved in a trial, which also includes institutions in Germany and Italy, to test the role of stents and IIb/IIIa agents in patients in the real world presentation of in acute myocardial infarction. The data from this trial, called ACE, will be available soon. The ACE trial includes 17% of patients with cardiogenic shock of TIMI 3, 70% of whom have been treated for for PCA in acute myocardial infarction. The interim analysis of this trial seems to show that the use of glycoprotein IIb/IIIa inhibitors have benefitted in patients with TIMI 3–TIMI 4 flow, treated with intervention. Of course, I think that complete revascularization is an important issue for patients in cardiogenic shock. We try to revascularize the patient completely if possible, even with PCI. Luis de la Fuente: As one of the oldest cardiologists here, I have enjoyed hearing so much of the history of Interventional Cardiology this morning. Most of the treatment modalities for cardiogenic shock have already been discussed today and I also absolutely agree that the patient in cardiogenic shock must be treated as soon as possible to open the occluded artery in the case of an acute myocardial infarction. I would like to comment on how we see cardiogenic shock from the South. First of all, allow me to review some history that may explain why we don't see as much cardiogenic shock in Argentina. With Favaloro, going back to 1969, we were convinced that myocardial revascularization was a very good procedure to improve blood flow to the ischemic heart, and the problem for us from then on would be the treatment of the acute coronary syndromes, especially the acute myocardial infarction and its complications. When we returned to Argentina from the U.S. in January 1970, we performed the first coronary angiography without any complications in 5 patients with acute myocardial infarction showing that this procedure was safe and feasible. In 1971, Favaloro wrote a book on myocardial revascularization and he said that one day acute myocardial infarction would be treated the same way that we were treating a “dead leg” — that is, given oxygenated blood to the infarcted area. However, at that time there was a good deal of pathological work in animals, primarily in dogs, showing that if oxygenated blood was given to an acute myocardial infarction area in the first hours, you would transform an anemic infarction into an hemorrhagic one and it would be very deleterious. We did not agree with this concept. On the contrary, we thought that monkey hearts would be more like our hearts. In 1972, we conducted studies in monkeys, ligating the left anterior descending artery and releasing the ligature after 6 hours and we could prove by left ventricular cineangiography that the left ventricular function improved dramatically after we released the ligature. Our studies showed that if we could revascularize the infarcted area in the first 6 hours, we could diminish the size of the infarct. From then on we started doing bypass surgery in acute myocardial infarction. Our work was presented at the American College of Cardiology meetings and was seen with enthusiasm by some doctors and with a lot of skepticism and criticism by others. We were invited to publish our experience, but our manuscripts were rejected by the reviewers, saying that the coronary and left ventriculogram pre and post were beautiful but that we were crazy. This is enough for the history. Years went by and physicians in Argentina gradually became educated on what to do when a patient with an acute myocardial infarction develops angina pectoris and/or continue to have ischemic changes either by EKG or Holter. It became evident that these patients could have an extension of the infarct or a new infarct in a different territory and they should be studied by angiography immediately. They also learned that in about 40% of the patients the first manifestation of coronary artery disease is an acute myocardial infarction or sudden death. If a patient has angina pectoris or others signs and/or symptoms of myocardial ischemia he has a real advantage because he can consult his cardiologist before any serious event. We stressed to the cardiologist that when a patient has an infarcted ventricular mass of near 40% he will go into cardiogenic shock and his prognosis will be very poor. We also told them that a patient with single vessel disease does not always have a relatively good prognosis. It is very important to know, not only the severity of the lesion and type of plaque, but also the location, the size of the artery and the absence or presence of adequate collateral circulation. A large left anterior descending artery can irrigate up to 33% of the left ventricular mass, very close to the 38-40% necessary to produce a cardiogenic shock. In our experience with acute myocardial infarction complicated by a severe mitral regurgitation produced by the rupture of the posterior papillary muscle, close to 25% of this patients had either a very large superdominant right coronary or circumflex arteries. These patients can also go in cardiogenic shock. In conclusion, I would say that the best treatment for cardiogenic shock is its prevention. Perhaps that is why, in Argentina, we currently don't see many patients in cardiogenic shock. However when we do see a patient with acute myocardial infarction in true cardiogenic shock we act more or less in the same way that Dr. Shawl has outlined. We also agree that there must be an cardiac interventionist on call 24 hours a day. James P. Zidar: Thank you for those comments. How about what’s going on in Italy? Are there any differences in the approaches you use? Gian Feltrin: We basically use the same approach. In northern Italy, we have the benefit now of a new public health system in which a patient can be transported to the hospital or moved to another facility very quickly. The territories are divided according to emergency specialties in many centers, the system (Phone M8) constitutes one of the most important changes implemented in Italy in the past five or six years. Secondly, there has been a significant drop in the number of cardiogenic shock patients — less than 5% of patients seen. Also, our operators frequently use intra-aortic balloon pump devices as well as counterpulsation because these devices allow for more prompt intra-arterial intervention. Thus, we can achieve rapid reperfusion and even potentially restrict the infarction. I must emphasize that at our centers, the use of these devices is very consistent, as seen in the literature. I don’t have hard data available, but I do know that these devices are widely used because cardiologists, cardiac surgeons and other practitioners can rather easily deploy them. With intra-aortic pump, we obtain an effective aid to the blood flow, and also, we offer a useful opportunity to coronary revascularization. On the other hand, in sudden failure, after surgery the intra-aortic balloon pumps are very effective and can greatly improve outcomes. James P. Zidar: I have two questions. First, do any of you have age criterion cut-offs? Paul, you alluded to the age factor when you mentioned that elderly patients above the age of 75 in cardiogenic shock have quite a high mortality rate. Do you treat everybody in your practices, or do you say, “Gee, the patient is over the age of 80 and is in shock; I’m not going to go to the trouble.” Fayaz Shawl: In my practice, if a patient is in cardiogenic shock, I don’t concern myself with his or her age, I just do the job. Paul Overlie: If there are specific family requests not to, we don’t. But generally we do, because one of the reasons we take patients to the cath lab and support them with a balloon pump is to determine exactly what the anatomy is and to risk stratify them for things that may occur downstream. Alfredo Rodriguez: Age is a risk factor for PCA and primary PTCA, independent of whether the patient is in cardiogenic shock or not. There is an ongoing trial — the SINIO (?) PAMI trial — which is attempting to answer the question about what the role of PCA is in older age. In patients in cardiogenic shock, I think we have to prioritize the shock over the age. In our practice, if a patient is in shock, regardless of age, we will attempt to do something. Luis de la Fuente: When we see patients in cardiogenic shock — especially women over 60 years of age — we have to rule out severe mitral regurgitation produced by a rupture of the papillary muscle. There is a high incidence of single-vessel disease in this group of patients. James P. Zidar: We actually have three hospitals that refer patients to our institution. These hospitals, which use Duke as a back-up center, have diagnostic labs, two of which are equipped for interventional procedures. If a patient comes in with an acute myocardial infarction and is stable, these hospitals will often hang on to the patient. But if the patient comes in with shock, they will usually put a balloon pump in and transport the patient to our facility. Dr. Magnus Ohman, who was at Duke for a long time and who is now at UNC in Chapel Hill, was trying to initiate a local balloon pump trial with the goal of getting local emergency room doctors to put balloon pumps in and then transport the patient to a center for angioplasty. One of the struggles Dr. Oman encountered was that the physicians who are most comfortable putting in balloon pumps are interventional cardiologists who perform a lot of cases and handle a lot of sick patients, not the physician who does an occasional case or does it without surgical back-up. It was thus difficult for Dr. Ohman to recruit patients. Would anyone in the audience or on the panel like to comment on how you handle a patient who presents in cardiogenic shock to a hospital located an hour from your facility? Paul Overlie: We used to fly over and put the balloon pumps in the patients ourselves. We don’t do that as often anymore due to fatigue, I suppose. Now we put the patients on pressors and transport them to our facility as quickly as possible. James P. Zidar: So you’re not having someone put the balloon pump in at the local emergency room? Paul Overlie: No. It’s under discussion again, but we haven’t instituted it yet. Gian Feltrin: In Italy, we have had extensive experience with thrombolytic therapy. One of the trials, called GISSI, studied streptokinase use. The results we obtained, however, were not convincing. If the thrombolytic, administered by rapid intra-arterial infusion, is used with the support of an intra-aortic balloon pump, the results are favorable. We have noted a reduction in mortality in normal terms. Kirk Garratt: We have been in the practice of encouraging our referring physicians within the Mayo Clinic healthcare system to send the patients promptly to us in order to get a balloon pump in place. As described earlier, we have a couple of hospitals that are now equipped and staffed to perform angioplasty on-site without surgical support. In those hospitals, we have made a decision to pull out all the stops: we will use aggressive therapies to treat patients and this includes using the intra-aortic balloon pump. The present challenge at those facilities is how to manage vascular complications among those patients, because hospitals that cannot support a cardiac surgeon usually have difficulty supporting a vascular surgeon as well. General surgeons can do some vascular work, but they are usually not very enthusiastic about managing your gigantic retroperitoneal hematoma at 2:00 am. The published complication rates with IABP still hover between 10–15%. I think the SHOCK data from Judith Hochmans’ study are very good. Good medical therapy with intra-aortic balloon pump therapy will provide life-saving treatment for the majority of patients and may rival what we can do for those patients when we take them to the cath lab. I also think that, at least in North America, most hospitals that cannot offer catheter therapy will also have a very difficult time offering safe and effective balloon pump therapy. James P. Zidar: For the sites that perform angioplasty, with Mayo Clinic backing them up, are they performing acute angioplasty with balloon pump on shock patients as well? Kirk Garratt: Yes. Those hospitals do handle “all comers.” However, we are still maintaining an expedited transport system for the shock patients. This is not done because of balloon pump concerns necessarily — which are very real — but simply because some of those patients will be in cardiogenic shock due to a blown out mitral valve or a VSD, or something requiring surgery. We do take these patients to the cath lab early so we can open up any occluded vessels that may need therapy. Paul Overlie: We actually instituted a similar program in the early- to mid-1980s with a center north of us where they placed the balloon pump, but the patient was brought back to the home hospital. I still feel better about that arrangement because those patients are extremely sick. All a smaller hospital needs is to have a couple of those patients die and its programs could be in jeopardy. (this discussion continues.... Please see Supporting Patients in Shock, part II)