Regarding “Aneurysm sac pressure measurements after endovascular repair of abdominal aortic aneurysms”

JOURNAL OF VASCULAR SURGERY Volume 35, Number 3

The search for a realistic method to determine “competence” may dwarf the search for the Holy Grail, but if certification is to be a major facet of that determination, then perhaps reappraisal of the criteria used for allowing one to obtain the vascular certificate should be considered. Dr Cronenwett closes by noting, “certainly our patients deserve better information for their vascular surgery shopping.” If any Board or Sub-board is going to provide that, the public deserves a less biased method to appraise what constitutes a competent vascular surgeon. Alan Berger, MD, FACS Lehigh Valley Hospital Allentown, Pa

REFERENCES 1. Hertzer NR, Avellone JC, Farrell CJ, Plecha FR, Rhodes RS, Sharp WV, et al. The risk of vascular surgery in a metropolitan community. With observations on surgeon experience and hospital size. J Vasc Surg 1984;1:13-21. 2. Ernst CB. The impact of vascular surgical training on vascular surgical care. J Vasc Surg 1987;5:403-4. 3. Kempczinski RF, Brott TG, Labutta RJ. The influence of surgical specialty and caseload on the results of carotid endarterectomy. J Vasc Surg 1986;3:911-6. 4. Squires JW, Johnson RE, Doyle L. Does the surgeon’s annual case load make a difference in the quality of peripheral vascular surgery? A report of the mortality, morbidity and long-term results of 101 procedures performed over 93 months. Arch Surg 1985;120:781-5. 5. Nahrwold DL. The competence movement: a report on the activities of the American Board of medical specialties. Bulletin ACS2000;85;11: 14-8. 24/41/121205 doi:10.1067/mva.2002.121205

Reply Dr Berger raises the important issue of the high-volume, noncertified vascular surgeon and cites some data suggesting that they may have outcomes similar to a certified vascular surgeon. We, too, are aware of a few surgeons in Ontario who trained in the era before the specialty of vascular surgery was formally recognized by the Royal College of Surgeons of Canada and training examinations developed. Unfortunately, we did not have an adequate sample size in our study to allow us to make definitive conclusions regarding their outcomes as compared with those of certified vascular surgeons, although we suspect they may be comparable. In defining a competent vascular surgeon, we agree that board certification, by itself, is not enough, and that an examination of actual contemporary risk-adjusted surgeon-specific outcomes is probably the best barometer by which to measure the competency of a particular surgeon. Nevertheless, our study suggests that on balance, patients who have their aneurysm surgery performed by surgeons with formal certification in vascular surgery have better patient outcomes. Jack V. Tu, MD Peter Austin, PhD K. Wayne Johnston, MD Institute for Clinical Evaluative Sciences Sunnybrook and Women’s College Health Sciences Centre University Health Network—Toronto General Division University of Toronto 24/41/121207 doi:10.1067/mva.2002.121207

Letters to the Editor 625 Reply I compliment Dr Berger and his associates on their excellent surgical results, and more importantly, for tracking these results. In fact, this was the point of my invited commentary, which concluded with the sentence, “It is time for vascular surgeons to monitor and report their outcomes.” The issues raised by Dr Berger concerning volume-outcome and certifying competency are both timely and important. There is little debate that highvolume hospitals and surgeons have better outcomes with volume-sensitive procedures, including arterial reconstruction. l This has led to suggestions for regionalization of such procedures. The Leapfrog initiative, organized by a consortium of health care purchasers for 20 million people, has now established minimum hospital volume requirements for carotid endarterectomy and elective abdominal aortic aneurysm repair.2 Such standards have the potential to disenfranchise low-volume hospitals (and surgeons), even if they have excellent results. However, the Leapfrog Group will grant hospitals a waiver from volume standards if they can demonstrate and publicly report satisfactory outcomes. 1 This again emphasizes the critical importance of monitoring outcomes in vascular surgery. The contribution of board certification to competence is a complex issue. It is unfortunate that a small number of vascular surgeons were disenfranchised by the ABS certification process if they had not accumulated a sufficient vascular caseload prior to 1989. However, a larger issue is how to establish ongoing competence by vascular surgeons after they achieve board certification. These issues are currently under intense review by all interested parties and should be of concern to all vascular surgeons. I appreciate Dr Berger’s highlighting these issues for us. Jack L. Cronenwett, MD Dartmouth-Hitchcock Medical Center Lebanon, NH

REFERENCES 1. Dudley RA, Johansen KL. Invited commentary: physician responses to purchaser quality initiatives for surgical procedures. Surgery 2001;130:425-8. 2. Birkmeyer JD, Finlayson EV, Birkmeyer CM. Volume standards for high-risk surgical procedures: potential benefits of the Leapfrog initiative. Surgery 2001;130:415-22. 24/41/121206 doi:10.1067/mva.2002.121206

Regarding “Aneurysm sac pressure measurements after endovascular repair of abdominal aortic aneurysms” We read with interest the article written by Baum et al (J Vasc Surg 2001;33;32-41) and congratulate them on presenting some valuable data. Type 2 endoleaks are becoming a difficult management problem. We are now realizing that they might not be as benign as originally thought, being capable of transmitting systemic and pulsatile pressure, therefore risking sac rupture. In Nottingham we have been performing intrasac injections of contrast (aneurysmograms or “sacograms”) to detect type 2 endoleaks for 3 years.1 The method we use is an endovascular one in which we gain access to the aneurysm sac intraoperatively via the contralateral common iliac artery. We have found the sacogram to be a useful predictor of subsequent type 2 endoleak. 2 If the sacogram shows patent side branch vessels, we go on to fill the aneurysm sac with

JOURNAL OF VASCULAR SURGERY March 2002

626 Letters to the Editor

polyvinyl alcohol sponge, thus obviating the need for further intervention. Using this method of intraoperative sacogram and aneurysm packing, we have reduced our type 2 endoleak rate from 9% to 1.3% (at completion of 2-year follow-up in 149 patients using our original, absorbable thrombogenic agent, Spongostan).3 The results in Dr Baum’s article have ignited further interest in intrasac embolization and aneurysm packing; however, we agree that the material of choice should be carefully chosen. Our method of packing the aneurysm sac was originally only applicable to uniiliac devices. It was feared that with bifurcated devices a large sheath would be required to be advanced between an iliac limb and the common iliac artery. More recently, we have devised a method of packing an aneurysm sac after bifurcated endovascular repair. Using smaller “bullets” of polyvinyl alcohol sponge, we have decreased the diameter of the introducer sheath to 11F and thus reduced the likelihood of injury to the iliac artery or disruption of the endograft limb. Robert Hinchliffe B. R. Hopkinson Department of Vascular and Endovascular Surgery University Hospital Nottingham, United Kingdom

REFERENCES 1. Walker SR, Macierewicz J, Hopkinson BR. Endovascular AAA repair: prevention of side branch endoleaks with thrombogenic sponge. J Endovasc Surg 1999;6:350-3. 2. Lehmann JM, Macierewicz JA, Davidson IR, Whitaker SC, Wenham PW, Hopkinson BR. Prevention of side branch endoleaks with thrombogenic sponge: one year follow-up. J Endovasc Ther 2000;7:431-3. 3. Hinchliffe RJ, Hopkinson BR. Experimental and clinical benefits by packing aneurysms after endografting. Proceedings of the 6th International Symposium on Critical Issues in Endovascular Surgery; 2001 Feb 23; Leiden, the Netherlands. 24/41/119237 doi:10.1067/mva.2002.119237

ings with any possible influence on the intimal layer, we quantified both intimal and media thickness and area of the same specimen with the aid of video morphometry. The degree of intimal hyperplasia was not reduced at clipped anastomotic sites compared with sutured ones. Similar findings were reported by Caiati et al.2 We suggested that, in our study, this might be the result of a comparison between a continuous (suture) and discontinuous (clip) anastomosing technique. In our experiments, we used nonanastomotic vessel segments as a control group, and, unlike Baguneid et al, we did not carry out the same experiments with interrupted sutures. In their study, differences in loss of compliance, as well as the total compliance mismatch across anastomoses, were most prominent when a continuous technique was compared with an interrupted technique (either suture or clip). There were no significant differences between interrupted sutures and clips. This may further support our previous hypothesis, that in fact the beneficial effects of an interrupted anastomosis, regardless of which material it is made of or if it is penetrating or not, have been measured. Further experiments will be needed to define more precisely the influence of the clips on the occurrence of intimal hyperplasia in the longer term. Clark J. A. M. Zeebregts, MD Department of Surgery Medisch Spectrum Twente Enschede, The Netherlands

REFERENCES 1. Zeebregts C, van den Dungen J, Buikema H, Tiebosch A, van der Want J, van Schilfgaarde R. Preservation of endothelial integrity and function in experimental vascular anastomosis with non-penetrating clips. Br J Surg 2001;88:1201-8. 2. Caiati JM, Madigan JD, Bhagat G, Benvenisty AI, Nowygrod R, Todd GJ. Vascular clips have no significant effect on the cellular proliferation, intimal changes, or peak systolic velocity at anastomoses in rabbit vein grafts. J Surg Res 2000;92:29-35. 24/41/121062 doi:10.1067/mva.2002.121062

Reply Regarding “A comparison of para-anastomotic compliance profiles after vascular anastomosis: Nonpenetrating clips versus standard sutures” Recently, several articles have appeared reporting the feasibility of using nonpenetrating VCS clips for vascular anastomosis, as well as the reduced anastomotic times with clips when compared with conventional sutures. However, there are very few articles that describe the effects of the clips on the vessel wall layers in detail. I would, therefore, like to congratulate Dr M. S. Baguneid and associates on their paper (J Vasc Surg 2001;33:812-20), in which they show that para-anastomotic compliance profiles are less reduced when using clips compared with sutures. It is concluded that this may lead to a reduced risk of anastomotic intimal hyperplasia in the longer term. Unfortunately, they failed to show any results of intimal thickness measurements and only gave us the description of what was seen in macroscopic view. In a series of pig carotid experiments, we showed the effects of the same clips on the vascular endothelium.1 It was found that endothelial relaxatory responses at the site of the anastomosis, as determined by adding pharmacological agents, remained better preserved with clips than with sutures. Scanning electron microscopy confirmed the better preservation of endothelial architecture after adding clips. To correlate these endothelial find-

We read with interest the comments made by Dr Zeebregts and would therefore like to clarify the main purpose of our study. Conventional anastomoses generate para-anastomotic flow disturbances on each side of the suture line, resulting in abnormal mechanical shear stress that may ultimately lead to endothelial cell loss, thereby initiating uncontrolled cellular proliferation. We compared the compliance profiles of continuous and interrupted sutured vascular anastomoses with those using nonpenetrating clips in the setting of acute nonrecovery in vivo experiments. It was therefore not relevant for us to record intimal thickness as a measure of intimal hyperplasia. Our main findings were that clipped anastomoses were quick and resulted in significantly better compliance profiles than continuous sutured anastomoses and similar profiles to those using interrupted sutures. However, there was significantly less acute endothelial injury seen in those using nonpenetrating clips. We therefore feel that the beneficial effects of both improved anastomotic compliance and reduced intimal damage may result in reduced intimal hyperplasia in the long term. We also congratulate Dr Zeebregts and colleagues for their work comparing endothelial preservation of clipped and continuous sutured anastomoses. They showed that the use of nonpenetrating clips in vein patch closure of an arteriotomy preserves greater endothelial function than continuous sutured closure. Yet,