ST-elevation myocardial infarction (STEMI)

STEMI Interventions Are “the Finest Indication” for PCI and Remain Urgently Needed Worldwide

Cath Lab Digest talks with Sameer Mehta, MD, FACC, MBA, Course Director, Lumen Global, Chairperson, Lumen Foundation, Miami, Florida
Cath Lab Digest talks with Sameer Mehta, MD, FACC, MBA, Course Director, Lumen Global, Chairperson, Lumen Foundation, Miami, Florida

It has been a few years since you last talked with CLD. Do you still have a STEMI-only practice?

Yes, it is now in its 12th year. The STEMI procedure is very inspiring and any sacrifices are made up for by its gratifying results. STEMI interventions remain the finest indication for percutaneous coronary intervention (PCI). 

Within your STEMI practice, what changes have you noticed over the past few years?

First, STEMI interventions have become easier and more predictable as the process has improved significantly. More patients are coming by ambulance, pre hospital alerts are the norm, false alarms and false positives (no culprit on angiography) are reduced, more emergency department (ED) bypass is occurring, teamwork has improved, and there is improved transfer process from non-PCI hospitals. Much still needs to be done in several areas, but the profound challenges of achieving door-to-balloon times (D2B) have become entirely surmountable.  

What challenges remain?

Patient awareness remains the biggest challenge. We must improve patient education and our interactions with the general physicians. Better integration of the HMO clinics and with their physicians is also required. Medical societies, community education, and philanthropic organizations can all contribute to this goal. Transfer from non-PCI institutions remains the Achilles’ heel of primary PCI and although there has been noteworthy progress in this area, much can still be done. Stringent transfer protocols and immediate availability of ambulance transport can improve. Pre hospital triage and ED bypass can be further improved. We can better integrate newer technology for pre hospital work, including initiating STEMI pharmacology in the ambulance. Finally, more insurance coverage with the new healthcare law will decrease financial pressures for institutions and physicians – for example, about 60% of our STEMI patients still have no insurance!  

Are these more local challenges or national trends?

Some issues are more local, such as the high rates of uninsured patients. But generally, the trends I described appear to be nationwide. Still, fantastic progress has been made in primary PCI in the United States. In 2006, in the first edition of the Textbook of STEMI Interventions, I had stated that the United States would take the global lead in primary PCI. I think this has already occurred, if you factor in the size of our country (as opposed to smaller European nations) and the large population. The U.S. has done a fantastic job with saving lives from heart attacks. American cardiology teams should feel very proud of this outstanding accomplishment and our patients should feel very fortunate. American cardiologists have single-mindedly dedicated themselves to this cause. The American College of Cardiology and American Heart Association have demonstrated flawless vision, and hospital administrators have been quick to respond to the huge demands of creating efficient STEMI programs. STEMI networks have matured in virtually every part of the nation, stakeholder support has expanded, and intelligent ambulance structures now exist throughout our vast country. Individual cardiologists have risen to the demand in a fantastic opportunity to save lives. Nurses and technologists, the unsung heroes in STEMI interventions, have been selfless. The gains of primary PCI, surprisingly, remain insignificant national news. Thousands of patients have survived heart attacks with completely preserved left ventricular (LV) function as a result the gallant devotion of these amazing cardiology teams, and because of their ability to create, and adapt as necessary, superb STEMI systems. Organizations such as Mission: Lifeline have led the way. Mission: Lifeline Chairperson Dr. Alice Jacobs deserves national and international recognition. 

Of course, some will dispute my blatantly optimistic evaluation. But they must realize that I have the vantage position of working in more than 30 countries with primary PCI. Countries are realizing how difficult it is to create ambulance networks and STEMI systems, and that saving lives predictably and nationwide is an exceptionally challenging task. 

What areas still need development?     

1. Improve patient awareness; 2. Streamline the transfer process from non-PCI institutions; 3. Standardize and optimize the STEMI procedure.

What needs to be done to standardize and optimize the STEMI procedure?

With all the process challenges, it is important to improve the STEMI procedure. With expert handling, the majority of patients (>95%) will have excellent outcomes. Yet with poor judgment and lack of attention to thrombus, the frail STEMI patient will deteriorate very quickly. STEMI interventions are increasingly becoming a very common procedure in most cath labs. Fellows in training must become proficient in the STEMI procedure using both transradial and transfemoral access. They should also maintain a standardized approach to performing a STEMI procedure.  The culprit vessel must be instantaneously diagnosed by electrocardiogram (EKG) and thrombus accurately assessed. Despite recent controversies about thrombectomy, stemming from the TASTE trial1, I remain a strong advocate of thrombectomy, but suggest a selective thrombus management strategy based upon thrombus grade. Performing complete angiography helps make a rational decision. You do not need multiple views. A single left anterior oblique (LAO) for the right coronary artery (RCA) when it is non-culprit and two orthogonal views if the left coronary artery (LCA) is non-culprit vessel, will suffice. As solid data has been aggregating, using drug-eluting stents to treat STEMI lesions appears prudent. Even in developing countries, drug-eluting stent use is increasing, as the gap between costs of drug-eluting and bare metal stents has narrowed. I remain a strong advocate for intra-coronary vasodilators that augment myocardial perfusion grade (MPG) and I universally employ intracoronary nitroprusside. I routinely evaluate left ventricular function, often with 8-10 cc of contrast media delivered with a hand injection. I use LV function to triage patients and to provide accurate results to the anxious patient and the family. Patients with normal LV function can proceed to early ambulation and discharge. However, impaired LV function is a reason to be cautious. The purpose of a quick assessment of LV function in the cath lab is not a substitute for an echocardiographic assessment that may be subsequently required, but it provides an early predictor that complements door-to-balloon time to forecast outcomes.  

I have used the above principles now for more than 1,200 consecutive short door-to-balloon procedures that comprise the SINCERE database (Single Individual Community Experience Registry). For the entire database, door-to-balloon times average 61 minutes and are stubbornly resistant to dropping further, as the first several hundred early procedures (2003-2007) had D2B times between 80 to 90 minutes. It is notable to mention that missing the 90-minute door-to-balloon time is unusual now, thanks in great part to ED bypass and predictable pre hospital alerts.

Similar to thrombectomy, performing PCI on non-culprit lesions is also controversial. Can you elaborate?

Thrombus management and addressing non-culprit lesions are the two most pertinent issues in STEMI interventions today. The academic positions are being calibrated in the midst of TASTE and PRAMI2 trials. I will lean on my experience from SINCERE to elaborate. Thrombus is dynamic; in the early hours of STEMI, there is the presence of easy-to-treat, friable, white thrombus that is platelet-rich. With delay to presentation and treatment, more dense and organized red thrombus is confronted. This is an aggregate of red blood cells and fibrin strands. The early, fresh thrombus is easy to aspirate, whereas the dense, red thrombus requires more aggressive strategies such as the AngioJet (Medrad) (with favorable anatomy). Most trials have not incorporated the dynamism of thrombus or duration to its presentation, instead advocating a single, all-comer strategy. I think this approach needs more pondering. Aspiration is less helpful in treating the late-presenting, dense and red thrombus. Similarly, AngioJet is less beneficial in treating the fresh and friable, white thrombus, unless it is voluminous and located in large, bulky vessels. To manage thrombus more effectively, I recommend a selective thrombus management strategy that is based upon thrombus grade (Figure 1).  

Regarding performing PCI on non-culprit lesions versus a strategy of deferring PCI for these lesions, it does appear prudent to defer PCI for non-culprit lesions. However, I want to narrate a different perspective and recommend some important caveats. As I mentioned, my practice has a very large number of uninsured patients. Their management must not differ from that of patients with insurance. Yet there are pragmatic issues to contemplate. During the initial STEMI presentation, a U.S. patient legally enters the healthcare system with considerable ease (there are more barriers in developing countries). However, hospitals will not authorize a second hospitalization for a staged procedure, ethics and high moral ground notwithstanding. Therefore, PCI of the non-culprit lesion has a financial merit. It does not and must not supersede scientific guidelines. Yet it is increasingly practiced in developing countries that confront massive financial constraints. Therefore, I view PRAMI for this pragmatic relevance.  

If one is to perform non-culprit PCI, I suggest two caveats — first, the result for the culprit STEMI lesion must be pristine, and secondly, the non-culprit lesion should be technically simple. 

Are Lumen’s global educational efforts with STEMI ongoing?

Yes, these efforts are ongoing and they are flourishing. A decade ago, people wondered about the sustainability of a STEMI-only practice and a STEMI-only meeting. We are on a determined path to succeed with both! Lumen Global, the subject-centric STEMI meeting, just completed its most successful 13th annual meeting in Bangkok, Thailand. It has slowly evolved beyond a meeting to become a STEMI movement. Lumen provides tools to the most vulnerable sections of the global society to save lives from acute myocardial infarction. The recent meeting had robust global attendance, a solid, CME-accredited academic agenda, a world-class faculty, scientific presentations from all countries of ASEAN (Association of South East Asian Nations) and enthusiastic efforts to improve both the STEMI process and procedure. Bangkok, as a venue, provided unprecedented hospitality. As the meeting has matured, numerous central themes that were discussed at Lumen Global have been adopted into practice by countless institutions. This is particularly gratifying when you understand that this transformation is occurring in countries such as Myanmar, Bangladesh, Cambodia and Vietnam — countries that have not yet been touched by most STEMI improvement efforts.  

Beyond providing pragmatic templates of improving the STEMI process and procedures in poor countries, Lumen Global has pioneered distinctive themes. These include STEMI interventions in women, urban pharmaco-invasive management, and empowering the general physician.  These important topics are iconic components of the meeting. STEMI networks and stakeholder development remain paramount and comprise important segments of Lumen Global. At the recent event in Bangkok, Lumen Global country directors from Thailand, India, China, Indonesia, Cambodia, Vietnam, Korea, Japan, Myanmar, Hong Kong, Singapore, Philippines, Malaysia, Bangladesh, UAE and Sri Lanka presented objective analysis of STEMI interventions in their respective countries, and received feedback and recommendations from European and American experts. Several of these developing countries have millions of patients that are vulnerable to acute myocardial infarction, most of whom are at least 15 years younger than patients in the western hemisphere. Countries such as Myanmar have just begun performing PCI and Lumen Global has urged them along to create STEMI programs and STEMI initiatives.  It is very gratifying to apply our best experience through Lumen Global to the most populous and most susceptible population.  

Over the years, you have been helping create STEMI networks and STEMI initiatives in other countries as well. How is that venture progressing?

Several years ago, we formed the Lumen Foundation to guide the Lumen Global meeting and to advance acute myocardial infarction care in developing countries. Today, this work is ongoing in more than 30 countries! In most countries, the focus is on helping to create massive, population-based STEMI programs. In others, it is working with local cardiac and medical societies, and with individual hospitals. This has been my most gratifying work and it is the best application of years of lessons learnt with SINCERE and with Lumen Global. The goal is unambiguous: saving lives from acute myocardial infarction. The method to reach that goal is to help poorer countries develop better systems to treat AMI. We recognize that it will not be possible for several countries to proceed to primary PCI, as they lack basic infrastructure. Figures 2a and 2b depict global STEMI epidemiology that helps in formulating strategies for Lumen Foundation and in developing the most meaningful agenda for Lumen Global. The global acute myocardial infarction chart makes it clear how unrealistic it is to expect countries that are in the 1st phase to perform primary PCI. How can you discuss pre-hospital work in an environment that lacks basic healthcare? By themselves, however, most of the developing countries will proceed to performing primary PCI. This amazing procedure can simply not be denied to save the life of a 35-year-old, just because he or she happens to be in a poor country. It is our goal to serve as a catalyst to help these countries move along the process and rapidly escalate through these elemental stages. 

About 7.2 million deaths occur from acute myocardial infarction globally.3 About 70% of these deaths occur in the areas covered by the Lumen Foundation. Often, the task is as simple as inspiring these countries and sharing our experience to provide them with the confidence that they can also work in this fashion. It is definitely possible to significantly reduce the mortality of acute myocardial infarction patients by offering a blend of techniques and systems. A few institutions might be able to perform primary PCI, some can be offered pragmatic pharmaco-invasive management, and others simply taught to use thrombolytic therapy more cost-effectively.  

In our work with several countries, the main point is to emphatically and unequivocally mandate urgent response. This simple instruct often goes to the root of a problem that has cultural and ethical basis. Several countries have fallen into the trap of using PCI during the day and thrombolytic therapy at night. It has been our experience that cardiologists want to do the best for their patients; they overwhelmingly trust primary PCI as the best treatment for their STEMI patients, and they are willing to sacrifice sleep and lifestyle to save lives. Their frustrations stem from lack of insurance, infrastructure, and resources.  

Our two best population-based works include the ongoing National Chinese STEMI-PCI study (> 6,000 patients enrolled, with an average door-to-balloon time of 117 minutes) and PRINCE (Puerto Rico Infarct Nationwide Collaborative Experience, www.accpuerto rico.org/prince) that has all PCI institutions and dedicated interventional cardiologists working in union to provide superb acute myocardial infarction care for the entire country, using standardized protocol, consent, and techniques.  

Are there other aspects of your work that you would like to highlight? 

Another fascinating and promising area is the use of telemedicine to provide a platform for comprehensive management of acute myocardial infarction. This simple and inexpensive technique can be effectively employed to reduce the gaps that exist in acute myocardial infarction care in developed and in developing countries. We have begun a pilot project in Brazil and in Colombia to demonstrate the effectiveness of telemedicine for managing STEMI care.

Visit www.lumenglobal.org to learn more.

Dr. Sameer Mehta can be contacted at mehtas@bellsouth.net.

References

  1. Fröbert O, Lagerqvist B, Olivecrona GK, Omerovic E, Gudnason T, Maeng M, et al; TASTE Trial. Thrombus aspiration during ST-segment elevation myocardial infarction. N Engl J Med. 2013 Oct 24; 369(17): 1587-1597. doi: 10.1056/NEJMoa1308789.
  2. Wald DS1, Morris JK, Wald NJ, Chase AJ, Edwards RJ, Hughes LO, Berry C, Oldroyd KG; PRAMI Investigators. Randomized trial of preventive angioplasty in myocardial infarction. N Engl J Med. 2013 Sep 19; 369(12): 1115-1123. doi: 10.1056/NEJMoa1305520.
  3. Trends of Acute Myocardial Infarction (AMI) in Singapore. A publication of the National Registry of Diseases Office, Singapore. November 28, 2013. Available online at https://www.nrdo.gov.sg/uploadedFiles/NRDO/INP-13-6_Health_Factsheet_AMI_rev1.pdf. Accessed March 24, 2014.