In Reply to: Case 0498_04 -- Aortic angiosarcoma, renal FMD, and iatrogenic axillary hematoma posted by Editor on March 31, 1998 at 14:52:58:
This is a great cases that raises several interesting issues. First, I'd like to thank the authors for submitting it so that the SCVIR membership could have the benefit of this on-line discussion. The questions they raise are difficult.
At the outset I would say that this is a very unusual case. A young woman presents with claudication and is found to have an angiosarcoma of the infrarenal aorta. Incidentally noted is bilateral FMD. She is treated successfully with chemo, radiation and surgery but in the process loses function of her left kidney. Seven years later, at age 41, the patient is alive (apparently cured) but suffers from poorly controlled hypertension and is discovered to have a significant right renal artery stenosis. Should she be treated? If so, how should she be treated?
Clearly this patient should be treated. She has poorly controlled hypertension. She is young and has a unilateral stenosis of the main renal artery most likely due to FMD probably the medial fibroplasia type. Ordinarily one would expect a good result with PTA - 85% benefit, and 50% normotensive without requirement for meds. But this is not an ordinary case. The patient has only one functioning kidney and she has undergone radiation, chemo and surgery in this area. Moreover, PTA at an outside institution was unsuccessful. So now what?
My first question is what is the disease process affecting the right renal artery. Is this medial fibroplasia. If so, one would expect a good response to PTA. Could it be intimal fibroplasia or perhaps a combined response of FMD and radiation injury, both of which are unlikely to respond to PTA.
My second question is how do you evaluate the technical result of FMD to PTA. By SCVIR guidelines technical success is defined as a less than 20% residual narrowing and significant hemodynamic improvement. With FMD though one often sees a very irregular post-PTA appearance that improves and smoothes over time. In general my approach to PTA for FMD has been to dilate the lesion and observe the clinical result. So I am not sure I would feel compelled to intervene further unless the patient continued to have uncontrollable hypertension. If she did, under ordinary circumstances at our institution she would undergo an operative reconstruction.
But again, this is not an ordinary case. The stakes are quite high. This is a young woman with a single kidney. A bad outcome to intervention makes this patient dialysis dependent. We are later told by the authors that the patient is not a surgical candidate. (The definition of "not a surgical candidate" is certainly operator dependent but in this case, I can understand that renal artery reconstruction in a post op, post radiation field would prohibitively difficult). So should you put a stent in the right renal artery and what results might you expect. Who knows? The mid term results with renal stents (2-5 yrs) are just being published (AJR 1997; 168: 245-251. JVIR 1996; 7:343-350. N Engl J Med 1997; 1997; 336:459-65). There appears to be a 10-20% incidence of restenosis. But few published series include any patients with FMD. So the answer does not lie in the published literature.
Clearly the main downside to stent placement in a location near the bifurcation of the main renal artery is that it will preclude surgical reconstruction or that restenosis will extend into the bifurcation branches making further endovascular therapy difficult. We have already acknowledged that the patient is not a surgical candidate. So if stenting is performed close clinical follow-up is necessary to identify restenosis early, at a point where reintervention is possible.
Finally, I should say that if I were asked to treat this patient my first reaction would be to ask the advice of someone more experienced than myself. So after reading this case, I called Lou Martin from Emory who has much more experience with renal artery intervention than I do. Lou told me that he has little experience stenting FMD because most of his patients who fail PTA go on to surgery.
In conclusion, the authors were presented with a very difficult case, where the risks of intervention were great. They concluded that the best therapeutic option for their patient (stent placement) was one for which little data is available. Their decision appears to have been a good one. The procedure was very successful with an impressive immediate angiographic and clinical result. I think we have all benefited from the presentation of this case and await further followup.