Addressing the Global Burden of Cardiovascular Disease: The Grenada Interventional Cardiology Pilot Program

Acknowledgements: The authors express thanks to Medtronic and ZOLL Corporation for donation of humanitarian supplies, Brendon LaGrenade, MBA, for administrative support, and Johansen Sylvester, MD, for medical support of the St. George University Adult Cardiology Clinic. In addition, we thank Lori Metayer, BSN, Shawn Metayer, C-RNA, Leigh Silver, Medtronic, and Annie Lanzieri, RT(R), for their assistance in performance of cardiac catheterization.

Editor's Note: Don't miss CLD's interview with Dr. Mark Lanzieri, "The Grenada Pilot Project: Behind the Scenes", at the end of the article.

Abstract

Aims. Cardiovascular disease is a global public health crisis. Detailed descriptions of cardiovascular interventions in emerging nations are limited. This report details development of a triphasic cardiovascular care program and initial results of coronary angioplasty in a limited resource setting. Methods and results. A prospective, real-world study of an indigent population requiring cardiac catheterization is presented. Coronary angiography was performed in 19 patients. Six patients underwent successful coronary angioplasty. No major adverse cardiovascular events were encountered. Conclusions. Cardiac catheterization and coronary angioplasty can be performed safely in a limited-resource setting.

The Grenada interventional cardiology pilot program seeks to provide needed cardiology services, objectify patient outcomes, and establish quality benchmarks for procedures performed in a resource-limited environment.

The United Nations’ 8 millennial development goals were established in 2000 and included the recommendation to address chronic disease.¹ The World Heart Federation has recommended integrating cardiovascular disease into the post-millennium development goal framework.² In the United States, the Institute of Medicine has further embraced this effort, seeking to both identify barriers to the global delivery of cardiovascular care and present a broad framework to address deficiencies in its local delivery. Among the potential barriers to care delivery are lack of disease awareness, limited health systems, and insufficient data on effectiveness.³ Located in the Eastern Caribbean, Grenada maintains free public access to primary health care. However, cardiology and vascular surgery are not represented in the system, and intensive care medicine is limited. Radiologic imaging in the public sector does not include vascular angiography. Ultrasound and computed tomography (CT) scanning are obtainable on a fee-for-service basis in Grenada’s private sector. As a result, the treatment of coronary disease is limited to medical therapy and most Grenadians are effectively denied access to interventional cardiology and cardiac surgery.

Despite global perceptions to the contrary, coronary disease is not uncommon in the developing areas of the Caribbean. The prevalence of coronary artery disease in Grenada can be estimated from two sources. A population study completed in 2012⁴ interviewed 2827 individuals and revealed the following risk factor profile: obesity (57.7%), diabetes (13%), hypertension (29.7%), cholesterol (8.6%), and smoking (7%). A self-reported prevalence of coronary artery disease of 2% was believed paradoxically low, given the shortcomings of self reporting, but even this percentage yields an incidence of 2000 individuals based on Grenada’s population of approximately 100,000.⁵ Given the social environment risk factor density, the true incidence of cardiovascular disease in Grenada may actually approach that in developed countries, where, for example, disease estimates are 5.2% of the general population of the United States.⁶ The second estimate, from the Pan American Health Organization⁷, indicates a prevalence of premature deaths from ischemic heart disease in Grenada of 33/100,000 population per year; consistent with rates across the Caribbean. However, this is an underestimation of the total population frequency of ischemic heart disease, because the cut-off age for analysis was 69 years. 

Even when ischemic heart disease is recognized, the ability to obtain advanced cardiovascular services in general and coronary revascularization specifically, is hampered severely by a lack of available programs and economic constraints. Although Caribbean-based coronary revascularization programs have demonstrated good outcomes, the largest published, retrospective series indicates 49% of patients had a low risk Euro score, which thus could represent the effect of selection bias on outcome. Furthermore, based on obtainable public data^8-11, case volume is generally fewer than 100 revascularizations per 100,000 individuals in the population. Applying identical regional selection criteria for coronary revascularization to a population of 100,000 with Grenada’s racial, cultural, and dietary characteristics would imply that at least 100 Grenadians a year would be candidates for revascularization. By contrast, per capita revascularization rates for the sum of coronary artery bypass grafting (CABG) and percutaneous coronary intervention (PCI) procedures in the U.S. and United Kingdom are estimated to be 409 and 207 per year per 100,000 individuals, respectively.^12,13 PCI has the potential to address this unmet need in the developed world if a program can demonstrate outcomes comparable to published reports of freestanding PCI programs without on-site cardiac surgery.

Methods

Since its inception in 2001, the Grenada visiting cardiology program, under the sponsorship of St. George’s University School of Medicine in Grenada, was envisioned as a triphasic program. All physicians are U.S. board-certified cardiologists committed to recurrent annual or semiannual participation. Programmatic Phase I included performance of consultative cardiology and echocardiography in both outpatient and inpatient settings. Phase II expanded services to implantation of permanent pacemakers for bradyarrhythmias, and performance of diagnostic coronary angiography centered on imaging quality and safety of vascular access. Phase III is coronary angioplasty with the intention to provide peripheral endovascular intervention and vascular surgery. A critical foundation of the program is the virtual hospital concept, which encourages bidirectional electronic communication between clinic staff, referring physicians, and cardiologists to enhance follow-up. Communication facilitates the triage of the critically ill to receive care as early as possible. 

Patients

The study population represents a continuous, prospective series of all patients with a clinical presentation consistent with ischemic heart disease from a free outpatient cardiology clinic or hospitalized setting. This includes a history compatible with angina pectoris, unexplained dyspnea in the presence of vascular risk factors, hospitalization with acute coronary syndrome manifested as elevation of troponin more than twice control, electrocardiogram (ECG) evidence of new diagnostic Q waves or evolving ST and T abnormalities, or echocardiographic evidence of ejection fraction less than 50%. 

Equipment

Diagnostic coronary angiography and intervention was performed on an OEC 9800 digital C-arm with vascular upgrade (GE Healthcare) and dedicated vascular imaging table. The OEC is a portable x-ray system designed for portable imaging of vascular procedures most commonly in an ICU setting and was not originally intended for cardiac catheterization or PCI. It utilizes a 120v single-phase power source at a maximum of 20 amperes. By comparison, imaging equipment used in the U.S. for angiography utilizes up to 360v 3-phase power at 600 amperes in order to produce higher quality images, but requires a complex and expensive system for heat dissipation. The OEC displays images on a traditional image intensifier of sufficient quality for the resolution of coronary arteries less than 1 mm and allows real-time playback, freeze frame, digital recording, and storage. Cine angiography is recorded at 7 or 15 fpm using either a 6- or 9-inch image intensifier. This equipment was purchased at a cost of approximately $200,000 USD, less than 20% the cost of a fully integrated catheterization and hemodynamics suite. Physiologic pressure recording, multichannel ECG monitoring, blood pressure (BP) monitoring, and emergency pacing and defibrillation capacity was provided by a ProPaq (ZOLL Corporation). These monitors are widely used in critical care medicine and trauma transport applications. To our knowledge, this is their first application as standalone catheterization laboratory monitoring systems. 

Procedural description

All sheaths, catheters, guides, balloons, wires, and stents for the pilot project were donated by Medtronic. All angiography was performed using contrast from the host hospital. All patients were loaded with dual antiplatelet therapy immediately prior to diagnostic catheterization and all interventions were done on an ad hoc basis. Indications for intervention were angina refractory to medical therapy, presentation with acute coronary syndrome with the preceding 90 days, and coronary anatomy such that an improved mortality could be anticipated with PCI. All implanted stents were bare metal platforms. The interventional anti-thrombotic agent was heparin in all cases. All cases are done using radial access. Post procedure, all interventional patients received 1 month of dual antiplatelet therapy. All diagnostic and interventional patients remained hospitalized a minimum of 24 hours post procedure. Baseline clinical and anatomic characteristics were collected and expressed as Euro score II and pre-procedural SYNTAX score. Residual SYNTAX score was determined in all post-interventional cases. All interventional cases were followed a minimum of 1 month post procedure.

Results

From February 2015 to May 2016, a single operator (ML) completed 26 coronary angiograms. Of these, 15 demonstrated normal coronary arteries, 4 had high risk anatomy with SYNTAX scores greater than 30 and 7 underwent PCI. No patient had myocardial infarction, stroke, or bleeding complications 24 hours post procedure. The mean Euro score for all interventional patients was 1.07. The mean pre procedure SYNTAX score was 14.3 and the mean post procedure SYNTAX score was 5.14. No patient experienced myocardial infarction, stroke, or death at 1 month of follow-up. One patient experienced an access site hematoma without compartment syndrome that resolved with conservative therapy. No other vascular complications were encountered.

Discussion 

Elective coronary angioplasty can be safely performed in hospitals without on-site surgical backup.¹⁴ Data presented in this series suggest radial access coronary angiography and PCI can be performed safely in a third-world setting with limited capital investment. The EuroSCORE II risk of 1.07 presented here is lower than regional comparisons of 2.989 and reflects conservative case selection appropriate for a pilot investigation. This is the first Caribbean dataset to include SYNTAX score, which was used both to guide patient selection and to predict equipoise with surgical outcomes for major adverse events. Patients with low or intermediate SYNTAX scores demonstrate similar rates of major adverse cardiac or cerebrovascular events at 12 months in either PCI or CABG cohorts. In addition, the rate of death, myocardial infarction, or stroke is similar in patients with 3-vessel disease for either PCI or CABG¹⁵, albeit at the risk of restenosis. PCI capable of achieving a residual post intervention coronary SYNTAX score less than 8 has been demonstrated to improve mortality.¹⁶ The pilot project was able to achieve this in a small study population with a low risk, mean pre procedural SYNTAX score appropriate for a pilot program. These data are also the first to demonstrate PCI can be offered safely at a low capital investment in the third world. As the program matures and selects patients with higher EuroSCORE and SYNTAX scores consistent with regional programs, the goal is to approach 50 cases per year, by year 5.

Percutaneous coronary intervention can offer comparable mortality outcomes compared to CABG, albeit at the expense of restenosis¹⁵, while offering a lower incidence of stroke. For populations unable to access CABG locally or regionally due to social and economic factors, restenosis is a reasonable risk — particularly for patients presenting with medically refractory angina. Although randomized, controlled trials do not demonstrate a universal mortality benefit for PCI for chronic stable angina, 32% of patients in the optimal medical therapy treatment arm of COURAGE required PCI at 5-year follow-up.¹⁷ In an environment where cardiology services are intermittent, patients who fail medical therapy cannot quickly and easily “cross over to an invasive arm” and receive urgent interventional services. Similarly, while achieving a “best outcome” based on randomized, controlled trials might require surgical revascularization, a “better outcome” with PCI that results in symptom relief or mortality benefit may be achievable.¹⁸ 

One study limitation is the inclusion of a greater than expected number of patients with normal coronaries. This is likely due to clinical selection criteria alone, due to the unavailability of risk-stratifying noninvasive testing. Yet the finding of normal coronaries is not without value, allowing individuals in a struggling economic environment to return to full, unrestricted employment, and may spare patients the inconvenience and not-insignificant cost of international travel to receive this diagnosis. Best estimates for the cost of coronary angiography and angioplasty for a Grenadian seeking this service off island in the greater Caribbean are $1800 USD and $15,000 USD, respectively.¹⁹ Having completed the current volume, performing this service locally has become cost neutral and sustainable with industry material donation.

Conclusion

This pilot program should serve to reinforce the need for public education for the prevention, recognition, and management of cardiovascular risk factors and disease.²⁰ Ideally it will stimulate a regional dialogue between government, health care providers, and economic stakeholders to address cardiovascular services in the Eastern Caribbean and other underserved areas. Through cooperative efforts and shared resources, regional centers could provide care for large numbers of indigent patients at reasonable cost. The scope of the global cardiovascular disease burden warrants active engagement of international societies of interventional cardiology to provide not just education, but on-site expertise on a regular, recurring basis. Active participation in service delivery on a recurring basis can be successful in parallel with the development of locally supported, long-term programs.

The authors report no conflicts of interest regarding the content herein.

Mark Lanzieri, MD, can be contacted at marklanzieri73@hotmail.com.

References

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15. Boden WE, O’Rourke RA, Teo KK, Hartigan PM, Maron DJ, Kostuk WJ, et al; COURAGE Trial Research Group. Optimal medical therapy with or without PCI for stable coronary disease. N Engl J Med. 2007 Apr 12; 356(15): 1503-1516. 
16. Généreux P, Palmerini T, Caixeta A, Rosner G, Green P, Dressler O, et al. Quantification and impact of untreated coronary artery disease after percutaneous coronary intervention: the residual SYNTAX (Synergy Between PCI with Taxus and Cardiac Surgery) score. J Am Coll Cardiol. 2012 Jun 12; 59(24): 2165-2174. doi: 10.1016/j.jacc.2012.03.010.
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The Grenada Pilot Project: Behind the Scenes

Questions for Mark E. Lanzieri, MD, FACC, FSCAI, Director of Interventional Cardiovascular Services, Grenada General Hospital, St. George’s University School of Medicine, Grenada, West Indies; Staff Cardiologist, Central Maine Medical Center, Lewiston, Maine.

Why is this work important?

First, there are immediate benefits conferred to patients who do not need to leave their family and social support networks. Second, this project demonstrates that a global public health issue can be addressed in a meaningful way with small scale, local solutions. Third, I believe an incremental approach to programmatic development is more beneficial in the long term than a “siege mentality” of performing a few high-profile interventions. Finally, our surgical and disaster medicine colleagues have been doing this for decades. The suffering from cardiovascular disease is less dramatic, but no less important. It is past time for interventional cardiologists to meet this challenge.

How and when did you become involved?

I came to the program in 2000 because of a connection to a prior cardiac nurse at Johns Hopkins. As a graduate who had completed cardiology training, I was one of the people she contacted for help. So I have been involved since the beginning. It was random at first, but my involvement has grown a great deal and I feel fortunate that she sent me that letter.

Others at Central Maine Medical Center have also become involved?

Yes. There is a rotating group of 10. Three are initial physicians from 2000, and the others we have recruited over time.

How does this project differ from other cardiology non-governmental organizations (NGOs)?

Our current successes are directly related to the participation of a group of physicians in a recurrent manner. Our cardiology clinic in Grenada is staffed 10 months a year and several cardiologists have staffed annual or semiannual clinics for 10 years now. Building relationships and trust from years of consultative cardiology has allowed us to assume more risk, performing pacemaker implantation and PCI, with the complete support of local physicians and government. One of the remarkable things I experience is receiving an email consultation or EKG when I am not in Grenada and providing management assistance in real time. 

Do you envision this program as a permanent solution or might it evolve in some way?

The problem is financial support, as you can imagine. A lot of the health care dollars in Grenada are consumed by primary, maternal, and trauma care. It is very unlikely they will ever get a freestanding cardiovascular program. We intend to continue for as long as we can keep it funded and humanitarian aid continues from corporate and industry sponsors, and St. George’s University. I would categorize it as probably an imperfect, permanent solution.

What are some of the future issues?

This work is critically dependent on humanitarian support from corporations including Medtronic, ZOLL, St. Jude Medical, Merit Medical, and Terumo that will hopefully always be available. In the absence of cardiothoracic or vascular surgery, it is important to continue to select cases at low or at most moderate risk, and not try to replicate cases I do in the U.S. Formally calculating SYNTAX risk and recording outcomes will remain a core feature of future development. We are exploring the possibility of low risk peripheral and structural intervention to serve the greater Eastern Caribbean region. However, current resources do not allow any arterial procedure that cannot be done via radial access, because a femoral complication could be catastrophic. Finally, we continue to seek involvement of U.S. hospitals — in addition to Central Maine Medical Center — that can consistently accept 1 or 2 surgical patients a year at no cost.

Are there challenges with the infrastructure? 

It was a challenge at one time. Some of our plans had to wait for things as basic as backup power to the operating rooms, which we did not have when we first started. We have been working in an operating room, which is powered, has backup power, and is a sterile environment. We have not been able to (and I don’t think we ever will be able to) get a freestanding cath lab in a different part of the hospital. We work with the infrastructure we are given.

How are your relationships with local physicians and staff?

We share emails frequently, both with the clinic staff and the 2 to 3 core referring physicians at the hospital. I get sent EKGs and short notes by email about patients who are active. About 2 weeks before I arrive, I make sure they know I am coming, and they set up cases that are active and need to be seen. We have an electronic relationship that is as good as some of the electronic relationships I have in my own office. In Maine, we have a large referral base geographically, and much of that communication is electronic. So it is no different in Grenada.

How many cases do you typically do in a visit?

We are doing 10 cases now over the course of a week. Some are angiography and some are permanent pacemakers. Ten cases a week seems to be what can be accommodated in the operating room schedule in a week’s time. We do have a room to use while we are there, and 10 seems to be what we can get done both in terms of scheduling and in terms of the resources we have allocated for the week. We obviously don’t have an endless supply closet, but with the donations, it allows us to do that number of cases on each trip. If we had more donations and more supply, we might be able to commit to more time, but we haven’t yet reached that point.

How much does the ability to take medication after receiving a stent play into your decision-making?

Right now, aspirin and clopidogrel are available on the island. I think that the most devastating thing would be for someone to not take those medicines after a stent in that kind of environment. We show up with a big bottle of Bayer aspirin and a generic bottle of clopidogrel, donated from my home hospital. We give them “Bottle #1” and “Bottle #2”, with 30 pills in each bottle, and we say, take one of each for a month. We can’t ensure compliance, but we can ensure they have dual antiplatelet therapy for 30 days. We have not put in any drug-eluting stents because the availability of medicine is not 100%, and people’s understanding of its importance is not 100%. A great stent is only great if it stays open.

You mentioned possible future expansion could include treatment of peripheral vascular disease. What are the challenges?

One problem is that the peripheral disease that I have seen in Grenada has gone unrecognized for so long that it is really to the point of amputation or chronic limb ischemia. Without a vascular surgeon, I think we would try an isolated, short segment of disease with a balloon in a peripheral circulation, but that is not the character of disease we are seeing. What is needed is a high-risk intervention and/or the association of a vascular surgeon. Two vascular surgeons have expressed interest in being involved in the program. However, they need additional imaging support, which we also don’t yet have. Peripheral disease is on our program’s growth curve, but I am not sure when that is going to happen, since we have to bring a lot of other items, meaning devices and equipment, online. It is the same thing with simple structural disease. We have talked about closing atrial septal defects or doing mitral cases at reasonable risk, but we don’t have a transesophageal probe and the echo machine is very old. It’s one of these things where you can’t do it until the infrastructure is built, but if you are not already doing cases, it is tough to find someone who wants to build the infrastructure or supply the equipment. We take it a little at a time. We have gotten this far and maybe we will take those other steps.

How have patients reacted?

The patients are delighted, because many of them were told, “There is nothing you can have done”, or “You have to leave the island and possibly go to the United States”, or “If you stay in the Caribbean, you’re going to have to pay a lot of money to have this done”. We do procedures I think can be done at a reasonable risk, in that kind of circumstance. Obviously there are things I do in my own cath lab that I wouldn’t try to do there. But for many people, this is life changing, whether it is a single-chamber pacemaker, a stent, or simply something that allows them to go back to work or keeps them out of the hospital. They have been very happy with the services we offer and the outcomes we’ve had.

How do others get involved?

Many people reading this are capable of replicating our project and other people reading this probably know of a locality that needs these services. The challenge is getting these two groups to find each other, and to work with their local institutions and industry representatives to form a long-term commitment to each other. I believe the involvement of an organization such as the American College of Cardiology (ACC), Society for Cardiovascular Angiography and Interventions (SCAI), or a global medicine group could provide the ideal sponsorship for idea exchange and networking. After initial contacts are made, individuals and institutions can then work out the logistics. Wouldn’t it be great to attend a session every year and hear the annual outcome data of a dozen small, international programs centered on humanitarian cardiovascular care? All of us involved in the St. George’s University Adult Cardiology Clinic and the Grenada Interventional Cardiology Pilot Program would be delighted to participate. One of the future directions, I think, is to encourage people in other places to replicate what we have done. We are happy to share our work and are hoping it stimulates some larger discussion and action.