What Was, What Is, and What Will Be!
On December 7th 1978, I participated in my first percutaneous transluminal coronary angioplasty (PTCA), and in February 1979, performed my first multivessel PTCA with a Schneider Medintag DG 2030 balloon catheter. At that time, lesion severity was determined by using visual estimation of percent diameter stenosis, utilizing Goffredo Genseni’s concepts within his book, Coronary Angiography (1975). Diameter stenosis was a proxy for percent area stenosis, which would correlate with flow impedance as detailed by Daniel Bernoulli (1700-1782), and Giovanni Venturi (1746-1822). While visual estimation (“guesstimates”) was repeatable, it was not anatomically accurate, as were other such methods as averaging of orthogonal angiographic views of lesion diameter stenosis. Intravascular ultrasound (IVUS) came onto the scene in the late 1980s and early 1990s; while IVUS was more precise and accurate when the images could be adequately defined, its adoption was minimal, since the catheters were cumbersome, required multiple exchanges, could not be used in many anatomical situations, were expensive, and not readily reimbursable. When intelligent guidewires were introduced, with a hollow construction enabling electrical measurement of translesion pressure, considered a reflection of lesion severity, their usage was limited to a minority of stable patients. Utilization of fractional flow reserve (FFR) and IVUS devices was not widely adopted because of several factors, including mechanical and performance characteristics of the hollow guidewire or large IVUS catheter, adenosine usage, and needed for multiple guidewire exchanges to obtain pre- and post-procedure data, which lengthened procedural time and radiation exposure. Even with the advent of better IVUS catheter equipment over time along with improved hollow guidewires, and the positive FFR FAME trial and IVUS outcomes data, utilization of FFR and IVUS devices remained limited.
In this month’s Journal of Invasive Cardiology, Dr Doh and colleagues’ focused communication1 provides a futuristic view of how interventional cardiologists should preform percutaneous coronary interventions (PCIs) employing both physiologic and structural tools so as not only to assess appropriateness, but also best procedural and long-term clinical results. This communication’s conclusions should be implemented, but hospital and health system administrators, insurers, and legislators will disregard the authors’ far-reaching conclusions (perhaps, crying too small a sample size) in order to limit the use of these devices within the diagnosis-related group (DRG), which will erode their profit margin. The increased costs associated with use of one, let alone both devices, the increased procedural time, the increase in complications associated with increased contrast usage, along with present procedural DRG reimbursement, all argue against their adoption and consistent usage. Presently, FFR penetration is in about 15% of the 30% of stable anginal patients, which constitutes only about 4%-5% of the entire PCI market in the United States, and IVUS usage is even less than that.
The synergy of FFR and IVUS, as reported, resulted in significantly improved clinical outcomes over that achieved with FFR alone. An IVUS minimal luminal area measurement after drug-eluting stent deployment of >5.4 mm2, along with an FFR >0.89, produced an improved 3-year survival free from target vessel failure when compared with those patients with an FFR <0.89.
But why has it taken so long, and required tenacious, diligent, and persevering investigators to show the synergy between these methodologies? Simply, present devices are not user friendly: (1) the hollow FFR wires are reticently used in unstable angina and ST-elevation myocardial infarction (STEMI) patients because of their mechanical and performance characteristics as compared with primary interventional guidewires; and (2) while IVUS catheter size has diminished, nevertheless, these IVUS catheters do not readily cross severe lesions, or facilely track through tortuous vessels (with/without stents). In addition, both devices require: multiple exchanges to complete the procedure so as to take pre- and post-procedure metrics; increased patient and physician radiation exposure; procedure prolongation; increased disposable costs without compensatory increased reimbursement; and decreased patient throughput. Presently, the combined usage of both devices, let alone one, is not looked upon favorably by myopic hospital and insurer administrators in the present DRG economic milieu. In fact, the overwhelming majority of patients never have these devices used, despite the knowledge that such metrics would improve clinical outcomes; this is justified by the fallacious argument that visual lesion assessment has done just fine, rather than by their adverse effect upon hospital profit margins. Since the majority of physicians are working for hospitals or health-care systems, which advise them of procedure appropriateness, finances rather than patient care become the primary and dominant determinant.
Obviously, the best answer to this conundrum is a primary interventional guidewire that would maintain its mechanical, performance, and steerable characteristics, while permitting stent deployment visualized in real time, as well as recording pre- and post-procedure metrics (eg, FFR and luminal area)and any structural issues. Such an intelligent guidewire would improve procedural and long-term clinical outcome results. However, such a guidewire does not exist. The integration of these two concepts (FFR and IVUS) within a primary interventional guidewire, such as Abbott’s Balance Middleweight (BMW) guidewire, would be ideal; just imagine, once the wire was placed, the pre-procedural metrics could be obtained, the appropriateness of the procedure documented, the stent deployed and expanded, and then the physiological and structural adequacy of the intervention assessed without ever having to move that “intelligent” BMW guidewire.
An intelligent primary interventional guidewire with all its physical attributes and in all iterations that can be facilely manipulated across every lesion, provide the metrics of FFR, the IVUS recording of the structural three-dimensional vessel anatomy without any pullback, the online live recording of stent expansion, the measurements assessing the adequacy of stent deployment, and then the post-procedural FFR to conclude the procedure is a fairy tale now, but dreaming, as far as I know, is not illegal. And, the implications of such a fairy tale device would be enormous for cardiology:
(1) The intelligent guidewire could be used on all cases of stable and unstable angina, as well as in non-ST elevation myocardial infarction (NSTEMI) patients, which constitute about 84% of the United State’s approximately 700,000 cases/year PCI market, while excluding the 16% STEMI patients, of which 50% have multivessel disease.2 Why? Because every interventional case has a guidewire placed.
(2) But let us go a step further, and consider multivessel angioplasty, ie, PCI of multiple vessels.
(a) In the United States, 75% of all PCIs performed are single-vessel angioplasties, and 55% of these patients have multivessel disease.3 If the authors’ advancements, and the reports of others, are true, then better clinical outcomes would occur in stable angina, NSTEMI, and multivessel STEMI patients with multivessel PCI, whether staged procedures or not. Then, it is possible that futuristic PCIs using an intelligent primary interventional guidewire would permit multiple lesions to be revascularized, which would lead to improved patient outcomes and lower complication rates. By intertwining FFR and IVUS into the primary interventional guidewire, the vast majority of PCI multivessel disease patients could have FFR and IVUS to determine lesion appropriateness, without exchanging any wires or catheters, ensuring the appropriate size and length of the stent chosen to fit the lesion anatomy, while observing online adequacy of stent deployment. The culmination of the procedure would be satisfactory post-procedure metrics that would best ensure the optimal clinical results. In addition, such a pathway could erode the usage of coronary artery bypass graft (CABG) surgery in the overwhelming majority of multivessel disease patients, as well as those hospital and rehabilitation expenses associated with surgery.
(b) Such a market shift would create certain financial realities: (1) more stent usage; (2) usage of a fictional intelligent wire in probably all PCI cases (why would the physician not use it?); (3) perhaps, even its usage in diagnostic angiography to determine whether intervention is warranted; and (4) increased reimbursement to cardiologists for performing more appropriately documented stent placements.
Now, let us consider the study pitting PCI versus CABG with FFR performed on all patients prior to any randomization. I am optimistic that this study’s results will not only support the premise the drug-eluting stent intervention is superior to CABG in multivessel disease, but that it will also show that the surgical results are better than prior CABG studies because surgeons now only operated on documented ischemic vessels; this would not be surprising if the same physiology that applied to interventional procedures also was applicable to bypass surgery, ie, anecdotal surgical stories abound about the results of bypassing non-critical lesions causing venous grafts to close immediately after surgery (documented by post-operative angiography), or an internal thoracic artery that did not hypertrophy and withered when placed distal to a non-critical left anterior descending coronary artery lesion.
Ted Kennedy paraphrased George Bernard Shaw at Robert Kennedy’s funeral. “Some men see things as they are and ask why. Others dream things that never were and ask why not.” This is how I think. I am an interventional cardiologist, who had the distinct pleasure of being involved with angioplasty in all its forms from its beginning. Nearly four decades have passed since the inception of interventional cardiology, which has grown and matured. However, what has unfortunately occurred is that the power derived from perspicacity, altruistic desires, knowledge, and patient welfare no longer remains in the hands of the physician, the interventionist. Today, large health-care businesses seduce cardiologists, concerned about economic stability, into giving up their independence, and their patients, by presenting bonuses and initially large contracts, which are not renewed or just have the salary lowered. Thus, cardiologists become technocrats, employed and dictated to by the health-care executives, whose focus is the bottom line, which results in mediocrity and nothing more; just look at some large health-care systems in the United States that have decimated their cardiovascular programs, while striving for the lowest cost possible. These are the sort of organization that will fight the introduction of an intelligent guidewire.
Nevertheless, Doh et al’s article makes me see a bright future that will improve and enhance patient care; but, for this to occur, cardiologists must remain strong, determined, as well as partnered with medical industry research to create and develop those fairy tale tools. Of course, I no longer perform interventions in the United States, do not work for any health-care or hospital system, have not participated in any federal, state, local, or private insurance plan for nearly two decades, and cannot be intimidated by such groups. I still believe that a better way should always be sought, and the status quo should be the embarking point to accomplish those dreams. I have always seen things differently, have done things differently; I hope that others will continue to remain true to the oaths we all took. The aforementioned are my opinions, those of a cowboy-cutting cardiologist, and using Dennis Miller’s words, “I could be wrong!”
References
- Doh JH, Nam CW, Koo BK, et al. Clinical relevance of post-stent fractional flow reserve and drug-eluting stent implantation. J Invasive Cardiol. 2015;27:346-351.
- Chan PS, Patel MR, Klein LW, et al. Appropriateness of percutaneous coronary intervention. JAMA. 2011;306:53-61.
- Dehmer GJ, Weaver D, Roe MT, et al. A contemporary view of diagnostic cardiac catheterization and percutaneous coronary intervention in the United States. A report from the cath PCI registry of the National Cardiovascular Data Registry, 2010 through June 2011. J Am Coll Cardiol. 2012;60:2017-2031.
- Gao Z, Xu B, Yang YJ, et al. Long-term outcomes of complete versus incomplete revascularization after drug-eluting stent implantation in patients with multivessel coronary disease. Catheter Cardiovasc Interv. 2013;82:343-349. Epub 2013 Apr 16.
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Gerald Dorros MD, ScD (Yeshiva University), ScD (Colby College), FACC, FESC, FACP, FSVMB, FAHA (emeritus), FCCP, FACA; Knight, Ecumenical Hospitalier Order of St. John - Knights of Malta, is the medical director of the William Dorros-Isadore Feuer Interventional Cardiovascular Disease Foundation in Wilson, Wyoming.
Disclosure: The author has completed and returned the ICMJE Form for Disclosure of Potential Conflicts of Interest. He reports that he is involved in, invested in, and lead director of Vascular Imaging Corporation, Rancho Cordova, CA, which is performing scientific experimentation and investigation of FFR and IVUS; the company has no commercial device.
Address for correspondence: Dr Gerald Dorros, The William Dorros-Isadore Feuer Interventional Cardiovascular Disease Foundation, Ltd, PO Box 1654, 1120 South Thunder Road, Wilson, WY 83014. Email: gdorros@dorrosfoundation.org
