Communicating the Benefits of Renal Artery Stenting

The safe and effective treatment of renovascular patients begins with educating everyone involved in the process of referral.

By Andrew B. Covit, MD, and Larry E. Shindelman, MD
 

To view the figure and table related to this article, please refer to the print version of our November/December issue, page 62.

Continuing advancements in the field of endovascular interventions have resulted in remarkable changes in traditional clinical practice patterns. Whereas traditionally trained vascular surgeons once held sway at the center of the noncardiac atherosclerotic vascular realm, advancements in endovascular technology, expertise, and capability among other practitioners within a specific community have resulted in new decision-making models, as well as the rethinking of referral patterns.1 Often, a medical subspecialist, such as a cardiologist or nephrologist, is consulted by the primary care physician to manage the vascular patient, recognizing that the various interventional options have only increased the complexity of clinical management of these difficult patients (Figure 1). Typically, these patients have multiple comorbid diagnoses, including diabetes mellitus, hypertension, chronic heart failure, and chronic renal failure; as a result they carry much higher than normal operative risks.2 The potential renovascular patient is often referred to the nephrologist as a result of renal failure and/or difficulty in hypertension management (Table 1).3,4

The patient with renovascular disease poses a particularly difficult clinical picture because the presentation is highly variable and often less than obvious.3 In our experience, patients are most often referred to a nephrologist because of newly discovered or progressive renal disease.5 Invariably, these patients also have evidence of diffuse atherosclerotic disease in addition to cardiac disease.5,6 This article discusses some of the factors involved in establishing effective referral patterns for endovascular interventions in the renal artery.

INITIAL REFERRAL
A long-term commitment on the part of the nephrologist to the ongoing high-quality care of all types of renal patients likely constitutes the single most important factor in ensuring a constant stream of referrals from the family practitioners, general internists, and medical subspecialists (endocrine, cardiology, and so forth) for potential renovascular evaluation. In fact, upcoming recommendations from the K/DOQI task force on hypertension in the chronic renal failure patient will place particular emphasis on the diagnosis and management of renovascular disease in the chronic kidney disease population.7 However, it is imperative for the nephrologist to artfully maintain a sense of “objectivity” advancing the diagnosis of a renovascular process as only one of several possible diagnoses. Furthermore, the efficacy of renal artery stenting procedures in the management of the renovascular patient remains controversial.3

A Typical Case
Recently, a 66-year-old woman was referred for evaluation of hematuria and proteinuria in the setting of modest hypertension, controlled on a daily combination angiotensin receptor blocker hydrochlorothiazide agent. The patient had a mildly elevated creatinine at 1.5 mg/dL. Neither the hypertension nor renal insufficiency was mentioned in the handwritten referral note sent with the patient by the internist. The note did, however, list the several studies already completed, including B-mode ultrasound, abdominal CT scan, and a MAG-3 nuclear renal scan. At the bottom of the note, ?Please evaluate for CRF? was written. This physician takes great pride in arriving at the diagnosis before the subspecialist without any of those ?fancy tests.?

After the physical examination, during which a periumbilical bruit was discovered, a lengthy discussion ensued that eventually convinced the patient (amid protestations against “not another test”) to undergo a repeat renal ultrasound, this time with renal artery Doppler analysis. Immediately, a highly appreciative and differential diagnosis-laden consultation letter was sent to the primary doctor (prior to discovering that indeed her renal artery duplex scan revealed a high-grade right renal artery stenosis). A follow-up telephone call once the results were available was met with significant appreciation and a discussion of the potential treatment options, followed by the referral of another patient.

Jumping to the renal artery diagnosis would have, in this case, insulted the internist, and his tendency to protect himself would likely overwhelm any high-minded admiration of the acute (read ?merely experienced?) diagnostician the next time a renal case came along. Everyone involved in clinical practice knows that referrals often follow perceived patterns of expertise. As a result of the typically clandestine nature of the renovascular ?syndrome,? this referral behavior might result in exclusion of many of the very patients that could benefit from renal artery evaluation. Initially, at least, a generalist approach serves best to initiate the renovascular investigation.

MAINTAINING REFERRALS
Several factors combine to help maintain a steady referral stream for renovascular endovascular procedures. First and foremost is clear-cut procedural excellence. Success rates for correct and appropriate stent deployment have to be extremely high when compared to evidence-based standards of care and, moreover, complications must be nearly nonexistent. Patient safety is paramount in the public consciousness as a result of the recent reports on medical errors.8 These are hard standards, but when faced with the controversies surrounding the optimal management of the patient with renal artery stenosis,3 they are absolutely mandatory.

Adequate experiential training for the endovascular physician is the focal point of this recommendation. Thought must be given to defining a “post”-fellowship year for vascular surgeons, interventional radiologists, and medical interventionalists (cardiologists, nephrologists, and so forth) to ensure adequate training in this burgeoning field. For those in active practice, a system of minimum standards for proctored experience in designated centers of excellence would provide the appropriate background training that would go beyond a 1- or 2-day course.9 This background will go a long way in generating confidence in the endovascular surgeon’s technical capabilities.

Practice guidelines, where possible, should be developed and employed so that all cases will be collected according to accepted standards for review. This will aid in the clinical efficiency of patient care and provide appropriate comfort for referring physicians. Such regimentation of care would also allow for a more rapid introduction and evaluation of new equipment and technologies by providing a robust baseline for comparisons. Providing the newest technique should only serve to further enhance the main message of clinical excellence and patient safety.

The second key ingredient in establishing and maintaining a steady referral stream again involves the aforementioned objectivity when dealing with the patient’s condition. The ability to say “No” to a referring physician because of technical or clinical limitations in a given case is a very powerful tool. Recent scrutiny of an open-heart program revealed that too many extremely high-risk patients were being operated on without significant chance for success either for the program (outcomes were suffering) or for the patients (high morbidity and mortality). It is imperative to remember that some patients are beyond our capacity to intervene. Recognition of this fact improves overall care, allows for measured efficacy for the interventional technology, and gives the referring physician some guidance as to future consultations.

Intertwined with this objectivity is the need to develop and convey a longitudinal view of the vascular patient. Strategies employed in the management of the renovascular patient come more from the game of chess rather than blackjack. By not merely focusing on the renal artery procedure at hand, but also at the patient’s care over time, continued referrals for other endovascular procedures will be commonplace, helping to maintain overall clinical competency.

Incorporating this long-term management scheme necessitates, at the same time, conveying early (even contemporaneous) and repeated updates to the referring physicians (both nephrologists and primary physicians), including them in the clinical care process. Offer continued follow-up as appropriate, but shift focus back to the referring practitioners as soon as possible. At the same time, communicate the need for predetermined follow-up requirements, such as at 30 days after the procedure, then again at 6 and 12 months. This goes a long way to foster the long-term approach to the patient’s care and also provides ample opportunity for research and documentation. Follow-up care can and should be provided by some combination of visits with the endovascular physician and the referring nephrologist, as determined by local standards of practice. In our practice, follow-up care involves linking the effect of renal artery stenting with preservation of kidney function by following anatomic changes with renal artery duplex scan and measuring preservation of kidney function with 24-hour creatinine clearance.

As in any area of rapid advancement, there are many factors that will impact on the delivery of care in the renovascular patient—clinical, economic, cultural, and otherwise. Integral to measuring the efficacy of an intervention is a constant review of data. In this new era of endovascular technologies, device manufacturers become de facto partners in the care of patients with renovascular disease, obligating them to support the review of data and thereby ensuring evidence-based medicine. Multicenter trials evaluating the revolutionary techniques and concepts involved in treating these challenging patients will likely yield a clearer clinical pathway for their management and result in improved outcomes and economic benefits.

Andrew B. Covit, MD, is Clinical Associate Professor of Medicine, Division of Nephrology, UMDNJ-Robert Wood Johnson Medical School, Medical Director of Outpatient Dialysis, St. Peter’s University Hospital, President of the Medical Staff, Robert Wood Johnson University Hospital, New Brunswick, New Jersey. Dr. Covit may be reached at (732) 390-4888; nephrohibp@att.net.
Larry E. Shindelman, MD, is a Clinical Associate Professor of Surgery, UMDNJ-Robert Wood Johnson Medical School, Director of the Endovascular Institute of New Jersey, New Brunswick, New Jersey. Dr. Shindelman may be reached at (732) 698-0606.

1. Criado FJ. On becoming an endovascular surgeon (editorial). J Endovasc Surg. 1996;3:140-145.
2. American College of Physicians: Guidelines for assessing and managing the perioperative risk from coronary artery disease associated with major non-cardiac surgery. Ann Intern Med. 1997;127:309-312.
3. Safian RD, Textor SC. Renal artery stenosis. N Engl J Med. 2001;344:431-442.
4. Mann SJ Pickering TG. Detection of renal artery stenosis: state of the art–1992. Ann Intern Med. 1992;117:845-853.
5. Shindelman LE, Covit AB. Clinical outcome of endovascular renal artery interventional therapy. In preparation.
6. Uzu T, Inoue T, Fugii T, et al. Prevalence and predictors of renal artery stenosis in patients with myocardial infarction. Am J Kidney Dis. 1997;29:733-738.
7. K/DOQI: Clinical Practice Guidelines for Blood Pressure Management and Use of Antihypertensive Agents in Chronic Kidney Disease. In preparation.
8. Chassin MR, Galvin RW. The urgent need to improve health care quality. JAMA. 1998;280:1000-1005.
9. Credentialing Criteria for Endovascular Surgery: Report from the Executive Board of the International Society for Endovascular Surgery. J Endovasc Surg. 1995;2:131-132.

 

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About Endovascular Today

Endovascular Today is a publication dedicated to bringing you comprehensive coverage of all the latest technology, techniques, and developments in the endovascular field. Our Editorial Advisory Board is composed of the top endovascular specialists, including interventional cardiologists, interventional radiologists, vascular surgeons, neurologists, and vascular medicine practitioners, and our publication is read by an audience of more than 22,000 members of the endovascular community.