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K Ivancev

Publications and source records attributed to K Ivancev.

At least 55 records · Page 3Linked to original sources
PubMed1998

The fate of the infrarenal aortic neck after open aneurysm surgery.

PURPOSE: The long-term success of the endovascular repair of abdominal aortic aneurysms is dependent on the secure fixation of the stent graft at the proximal and distal attachment sites. A progressive dilatation of the infrarenal neck may jeopardize this success. The data regarding this issue are scarce. However, the long-term fate of the infrarenal neck can be studied in patients who have undergone open aneurysm surgery. This was the purpose of the present investigation. METHODS: Between January 1989 and December 1993, 64 patients underwent open repair of infrarenal abdominal aortic aneurysms. Of the 36 patients who were eligible for the study, 19 had preoperative computed tomography scans that were available. The 19 patients also underwent a new computed tomography scanning at a mean of 71 +/- 12 months after surgery. RESULTS: The mean preoperative aortic diameter was 25.4 +/- 3.7 mm at the infrarenal neck, 24.8 +/- 3.4 mm at the level of the renal arteries, and 26.7 +/- 3.0 mm at the level of the superior mesenteric artery (SMA). The mean aortic diameter increased at all of the 3 levels: +2.8 +/- 3.1 mm (P =.0014) at the infrarenal neck, +2.8 +/- 3.0 mm (P =.0013) at the level of the renal arteries, and +1.3 +/- 3.0 mm (P = .080) at the level of the SMA. The annual growth rate was 0.48 mm/y (P = .0023) at the infrarenal neck, 0.46 mm/y (P =.0010) at the level of the renal arteries, and 0.21 mm/y (P = .5811) at the level of the SMA. No correlation was found between the preoperative infrarenal neck diameter (r = .295, P = .2194), the preoperative aortic diameter at the level of the renal arteries (r = .302, P = .2088), and the preoperative aortic diameter at the level of the SMA (r = .314, P =. 2043) and the corresponding growth rates. The patients were stratified into 2 groups one with a small annual growth rate at the infrarenal neck (n = 11; </= 0.3 mm/y) and one with a larger annual growth rate (n = 8; > 0.3 mm/y) and no differences in the preoperative infrarenal neck diameter or the clinical characteristics were found between the groups. CONCLUSION: This investigation shows an aortic dilatation of the infrarenal neck and of the aorta at the level of the renal arteries of approximately 0.5 mm annually after open aneurysm surgery. This dilatation raises concern regarding the long-term success after endovascular repair. The data also indicate that 2 populations might exist with regard to the annual growth rate of the infrarenal neck one with low growth rate and one with higher growth rate. This might be of interest for the future selection of patients for endovascular repair.

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PubMed1998

Persistent collateral perfusion of abdominal aortic aneurysm after endovascular repair does not lead to progressive change in aneurysm diameter.

PURPOSE: To differentiate between the phenomenon of collateral perfusion from a side branch versus graft-related endoleaks after endovascular repair of abdominal aortic aneurysms (AAA), with respect to aneurysm size and prognosis. METHODS: We successfully treated 64 AAA patients with endovascular grafting. We followed all the patients postoperatively with spiral computed tomography at one, three, six and 12 months, and biannually thereafter. We measured aneurysm diameters preoperatively and postoperatively. We calculated preoperatively the relation of maximum aortic diameter (D) to the thrombus-free lumen diameter (L) expressed as an L/D ratio. Median follow-up was 15 months. RESULTS: Sixteen patients had collateral perfusion during follow-up. We successfully treated two patients with embolization. One patient showed resolution of collateral perfusion after we stopped warfarin treatment. Two patients died of unrelated causes during follow-up. One patient was converted to surgical treatment, and two patients showed spontaneous resolution of their collateral perfusion. The group of patients with perfusion showed no statistically significant change of their aortic diameter on follow-up. The group of patients without perfusion showed a median decrease in aortic diameter of 8mm (p < 0.0001) at 18 months postoperatively. The group of patients with perfusion had significantly less thrombus in their aneurysm sac preoperatively than the group without perfusion, as expressed by the L/D ratio (mean L/D 0,61 versus 0,78, respectively; p=0.0021.) CONCLUSION: There was no significant increase in aortic diameter on an average 18 months postoperatively despite persistent collateral perfusion. This may indicate a halted disease progression in the short term. Embolization of collateral vessels is associated with risk of paraplegia. We recommend a conservative approach with close observation if aneurysm diameter is stable.

Adult↗
PubMed1998

Reduced pulsatile wall motion of abdominal aortic aneurysms after endovascular repair.

PURPOSE: The reduced size of abdominal aortic aneurysms (AAAs) after endovascular repair suggests lowered intraaneurysmal pressure. In the presence of endoleaks, the size is not decreased. Although postoperative intraaneurysmal pressure is difficult to record, the pulsatile wall motion (PWM) of aneurysms can be measured noninvasively. The aim of this study was to assess the PWM of AAAs before and after endovascular repair and to relate the change in the PWM to aneurysmal size and presence of endoleaks. METHODS: Forty-seven patients underwent endovascular repair of an AAA. The aneurysm diameter and PWM were measured with the use of ultrasonic echo-tracking scans preoperatively; at 1, 3, and 6 months; and thereafter biannually. Fifteen aneurysms developed endoleaks, whereas 32 were completely excluded. The leaks were characterized with the use of computed tomographic scanning and angiography. Median follow-up was 12 months (interquartile range, 5 to 24 months). RESULTS: The preoperative PWM of the aneurysms was 1.0 mm (range, 0.8 to 1.3 mm). After complete endovascular exclusion, the PWM was 25% (range, 16% to 37%) of the preoperative value (p < 0.001), and aneurysm diameter decreased by 8 mm (range, 6 to 14 mm) (p < 0.001). After 18 months, no further diameter reduction occurred. In three patients without endoleaks but with enlarging aneurysms, the postoperative PWM showed less reduction (p < 0.05). Aneurysms with endoleaks showed no diameter decrease, and the postoperative PWM was 50% higher than that in the totally excluded cases (p < 0.01). In five patients with transient endoleaks, the PWM was reduced after leakage ceased (p < 0.05). Leaks of various sources displayed similar PWM. CONCLUSION: The size and PWM of aneurysms are reduced after endovascular repair. The diameter reduction may cease after 1.5 years. Endoleaks are associated with higher PWM than expected. Pressure may be transmitted without evidence of leaks.

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PubMed1998

Postoperative fever, bowel ischaemia and cytokine response to abdominal aortic aneurysm repair--a comparison between endovascular and open surgery.

OBJECTIVES: To study bowel ischaemia in transfemorally placed endoluminal grafting (TPEG) for abdominal aortic aneurysms, and any relation to cytokine response or postoperative fever. DESIGN: Prospective not randomised. University hospital setting. MATERIAL: Fourteen cases of conventional surgery and 23 cases of endovascular technique for infrarenal abdominal aortic aneurysm repair. METHODS: Tonometry was used for sigmoid colon pH, and ELISAs for serum IL-6. RESULTS: Mucosal pH in the sigmoid colon fell significantly during clamping and reperfusion in both groups. Lowest measured sigmoid colon pH was 7.10 in the open group, compared to 7.22 in the TPEG group (p < 0.05). The IL-6 levels in serum peaked after 4 h of reperfusion; 249 pg/ml in the open group, compared to 89 pg/ml in the TPEG group (p < 0.05). High levels of IL-6 in the postoperative period and persisting low sigmoidal pH were associated with serious complications. Postoperative temperature did not differ significantly between the groups, and no significant correlation could be found with sigmoid colon pH or IL-6 levels. CONCLUSIONS: The less pronounced perioperative bowel ischaemia in TPEG patients indicates an advantage of the TPEG technique. Splanchnic ischaemia was not related to postoperative fever, nor the IL-6 or TNF response.

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PubMed1998

Late aortic arch perforation by graft-anchoring stent: complication of endovascular thoracic aneurysm exclusion.

PURPOSE: To describe a fatal case of late aortic perforation by an endograft-anchoring stent. METHODS AND RESULTS: A 69-year-old woman presented 2 years after thoracoabdominal aneurysm repair with a 9-cm dilatation of the descending thoracic aorta proximal to the conventional aortic graft. A 38-mm Dacron graft with multiple Gianturco Z-stents sutured inside was placed transluminally across the aortic arch such that part of the uncovered portion of the proximal stent was partially across the left subclavian orifice. Four months later, the patient died from massive hemorrhage. Autopsy showed that the uncovered portion of the proximal stent had perforated the aortic arch. CONCLUSIONS: This case stresses the need for low-profile stent-grafts and smaller, more flexible introducer systems. Anchoring stents must be flexible, less traumatic, and strong enough to create a watertight seal even in tortuous vessels. To avoid aortic arch damage by thoracic stent-grafts, the proximal stent should be fully covered by the fabric.

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PubMed1998

Endovascular AAA exclusion: will stents with hooks and barbs prevent stent-graft migration?

PURPOSE: To investigate if stents with hooks and barbs will improve stent-graft fixation in the abdominal aorta. METHODS: Sixteen- to 24-mm-diameter Dacron grafts were deployed inside cadaveric aortas. The grafts were anchored by stents as in endovascular abdominal aortic aneurysm repair. One hundred thirty-seven stent-graft deployments were carried out with modified self-expanding Z-stents with (A) no hooks and barbs (n = 75), (B) 4 5-mm-long hooks and barbs (n = 39), (C) 8 10-mm-long, strengthened hooks and barbs (n = 19), or (D) hooks only (n = 4). Increasing longitudinal traction was applied to determine the displacement force needed to extract the stent-grafts. The radial force of the stents was measured and correlated to the displacement force. RESULTS: The median (interquartile range) displacement force needed to extract grafts anchored by stent A was 2.5 N (2.0 to 3.4), stent B 7.8 N (7.4 to 10.8), and stent C 22.5 N (17.1 to 27.9), p < 0.001. Both hooks and barbs added anchoring strength. During traction, the weaker barbs were distorted or caused intimal tears. The stronger barbs engaged the entire aortic wall. The radial force of the stents had no impact on fixation, while aortic calcification and graft oversizing had marginal effects. CONCLUSIONS: Stent barbs and hooks increased the fixation of stent-grafts tenfold, while the radial force of stents had no impact. These data may prove important in future endograft development to prevent stent-graft migration after aneurysm exclusion.

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PubMed1998

Dilatation of the infrarenal aneurysm neck after endovascular exclusion of abdominal aortic aneurysm.

PURPOSE: To determine the fate of the infrarenal aneurysm neck and suprarenal aorta after endovascular exclusion of abdominal aortic aneurysms (AAAs). METHODS: Thirty-four patients underwent endovascular AAA repair between January 1994 and December 1995 using custom-made stent-grafts constructed from polyester graft material and modified self-expanding Gianturco Z-stents sutured to the graft orifices. Thirty-one patients were available for follow-up. Pre- and postimplantation diameters were measured using spiral computed tomography in the infrarenal aneurysm neck and the suprarenal aorta at the level of the superior mesenteric artery (SMA). RESULTS: The mean follow-up time was 25 months. There was a significant increase of the diameter of the infrarenal aneurysm neck (+ 1.65 mm, p = 0.002), but not in the aorta at the level of the SMA (+0.52 mm, p = 0.100). There was no difference in the change in diameter in the infrarenal neck in the group with a stent adjacent to the level of measurement (n = 20) compared with the group without an adjacent stent (n = 11, p = 0.790). There was no correlation between preimplantation size of the infrarenal neck and its diameter change (r = 0.14, p = 0.488). There was no correlation (r = 0.10, p = 0.603) or association (chi-square test, p = 0.211) between aortic diameter change at the level of the SMA and the infrarenal neck. CONCLUSIONS: This investigation shows a significant dilatation of the infrarenal aneurysm neck, but not in the suprarenal aorta, after endovascular AAA repair with this device. The clinical significance of these findings is unclear. Whether such a dilatation in the infrarenal aneurysm neck may affect the long-term attachment of stent-grafts remains to be shown in the future.

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PubMed1997

Early results of endovascular aortic aneurysm surgery with aortouniiliac graft, contralateral iliac occlusion, and femorofemoral bypass.

PURPOSE: The aim of this study was to evaluate the feasibility of endovascular aortic aneurysm repair with use of an aortouniiliac graft secured with self-expanding (Gianturco) stents. METHODS: Thirty patients with a median age of 72 years (age range, 52 to 86 years) and aneurysm diameter of 6.0 cm (range, 4.0 to 9.0 cm) were treated with an aortouniiliac endovascular graft. Of these 30 procedures, 28 were carried out electively and two as emergencies for leaking aneurysm. Of the 30 patients, 21 (70%) were considered to be at high risk for open surgery. A modified Gianturco stent, Dacron graft, and Wallstent were used for these procedures. RESULTS: Endovascular repair was successfully carried out in 25 of 30 (83.3%) patients. All these patients were mobile and had resumed a normal diet within 48 hours of the procedure. The overall 30-day mortality rate was two in 30 (6.6%), but it was one in 28 (3.5%) for the elective cases; all deaths occurred in the group at high risk for surgery. Other complications encountered within 30 days of procedure included myocardial infarction in one patient, pneumonia in two patients, homonymous quadrantanopia in one patient, and colonic ischemia in one patient, giving an overall morbidity rate of four in 30 (13.3%). At a median follow-up of 4 months (range, 1 to 13 months), 27 of 30 (90%) patients remain alive and well. CONCLUSION: Endovascular aortouniiliac repair of abdominal aortic aneurysm with Gianturco stent is feasible in both elective and emergency situations. It appears to be minimally traumatic, and the majority of patients deemed to be at high risk for open surgery can safely undergo endovascular repair. However, data on more patients with longer follow-up is required to determine its role in the management of abdominal aortic aneurysm.

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PubMed1997

The effect of endovascular aortic stents placed across the renal arteries.

OBJECTIVES: To investigate renal artery patency and renal function after deployment of aortic stents covering the orifices of renal arteries. DESIGN: Prospective open animal study. SETTING: Department of Experimental Surgery at a university hospital. MATERIALS: Twenty-three pigs were used. METHODS: Ten pigs were observed for 1 h after graft-anchoring aortic stents, Gianturco (5) and Palmaz (5), were placed so that the stents covered the renal arterial orifices. In 13 pigs, Gianturco (6) and Palmaz (7) stents without grafts were placed over the renal arteries and left in situ for 7 days. Renal function and blood flow were measured by renograms, iohexol clearance and ultrasonic blood flow meter and patency was verified by angiograms. The kidneys were microscopically examined for signs of ischaemia and microemboli. RESULTS: One renal artery covered by a graft-anchoring Gianturco stent occluded. The remaining renal arteries remained patent without any significant decrease in renal blood flow after stent deployment. Normal renal function and histology was maintained. CONCLUSIONS: Aortic stents placed at the level of the renal arteries do not affect renal blood flow within 1 week in this experimental model. This may prove valuable in endovascular treatment of aortic aneurysms and in other procedures involving stents.

Animals↗
PubMed1997

A telescopic stent-graft for aortoiliac implantation.

OBJECTIVES: To test a new delivery system for a telescopic stent-graft. MATERIALS: Variable overlap between the components of this stent-graft combination allows length adjustment. This device differs from other multi-component stent-grafts in that both components are contained within a single delivery system. METHODS: The stent-graft was implanted in the distal thoracic to suprarenal aorta of five pigs (35-50 kg), where the arterial diameter falls by almost 50%. The proximal and distal components of the stent-graft were targeted to bony landmarks in the vertebral column. RESULTS: Inspection of completion angiograms showed both proximal and distal stent-grafts to be within 1 mm of their target locations in all five experiments. Overall combined stent-graft length varied from 13.5 cm to 16.1 cm depending on the location of the bony landmark chosen as the distal target, and on the size of the pig. CONCLUSIONS: This system may be useful for the repair of abdominal aortic aneurysm whenever preoperative sizing is difficult due to aortic tortuosity, or precluded due to the urgency of the procedure.

Animals↗
PubMed1997

Aneurysm pressure following endovascular exclusion.

OBJECTIVES: To assess the effect of stent-graft implantation on the pressure within an abdominal aortic aneurysm. METHODS: Aneurysm exclusion was performed using an aorto-uniiliac stent-graft in eight patients. Following stent-graft implantation, pressure measurements were performed through a catheter adjacent to the graft in the aneurysm. This "aneurysm pressure" was compared with radial arterial pressure. RESULTS: The pressure was lower in the aneurysm than in the radial artery, in all cases. Mean aneurysm pressure was 36.5/33.8 mmHg, while mean radial arterial pressure was 118.5/50.5 mmHg (p < 0.05, for both systolic and diastolic pressures). These findings corresponded with a reduction in the palpable abdominal pulse, and an absence of perigraft perfusion on follow-up computerised tomography. CONCLUSION: Stent-graft implantation produces a fall in the pressure within an abdominal aortic aneurysm.

Aortic Aneurysm, Abdominal↗
PubMed1997

The use of intravascular ultrasound as control procedure for the deployment of endovascular stented grafts.

OBJECTIVE: To assess whether intravascular ultrasound (IVUS), used systematically in a series of patients with abdominal aortic aneurysms (AAA), is a feasible control procedure to ensure correct transfemoral placement of endovascular stent grafts (TPEG). DESIGN: Descriptive study. MATERIALS AND METHODS: Fourteen patients with infrarenal aortic aneurysms were treated by the placement of one tube graft, 10 aorto-uni-iliac and three aorto-bi-iliac grafts. Arteriography and IVUS were performed before, during and after deployment of the graft to ensure correct placement in relation to side branches, and proper adaptation of the stents to the aortic wall. Postoperative CT-scan and arteriography served as control procedures. RESULTS: IVUS identified both renal arteries before graft deployment in eight of 13 (62%) patients. In the remaining patients only one renal artery was visualised due to interference from guidewires or the introducer system. Imaging during stent deployment was abandoned after IVUS catheter damage in two of three cases. Postprocedural IVUS was able to evaluate the expansion of the stents and the adaptation to the aortic wall in all instances. In four (29%) cases a leak was identified. Additional intervention included deployment of a further stent (n = 2) or redilation (n = 2). Covering of the renal arteries could only be indirectly determined by IVUS. CONCLUSION: IVUS can provide important decisive information before and after stented graft deployment, with the limitations that guidewires, introducer system and stents may cause interference. Contemporary IVUS designs are unsuitable for monitoring stent deployment.

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PubMed1997

Renal arteries covered by aortic stents: clinical experience from endovascular grafting of aortic aneurysms.

OBJECTIVES: During the endovascular repair of abdominal aortic aneurysms (AAAs), effective anchoring of the stent-graft is difficult in the presence of a short infrarenal aneurysm neck. The aim of this study was to investigate renal artery patency and renal function after deployment of graft anchoring stents across the renal arteries. DESIGN: Retrospective open study. PATIENTS: Twenty-five renal arteries, in 18 patients treated by endovascular exclusion of an AAA, were intentionally covered with the Gianturco Z-stent to ensure stent graft attachment. METHODS: Renal artery patency was assessed by repeated spiral computed tomography (CT) scans and angiography. Creatinine levels, blood pressure and antihypertensive medication were recorded. Follow-up was a median 6 months (2-9). RESULTS: All 25 stent-covered renal arteries remained patent. CT showed a small infarct in one kidney. Creatinine was 108 mumol/l (89-133) before intervention and 98 mumol/l (87-127) at follow-up. Blood pressure was 150/80 mmHg on both occasions. Antihypertensive therapy was intensified in one patient whose creatinine level remained stable and whose separate renin sampling was normal. CONCLUSIONS: Covering the renal arteries with the Gianturco Z-stent does not seem to affect renal function within 6 months. Further follow-up is needed before suprarenal stent deployment can be advocated.

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PubMed1997

Abdominal aortic aneurysms: experience with the Ivancev-Malmö endovascular system for aortomonoiliac stent-grafts.

PURPOSE: To describe a component-based aortomonoiliac stent-graft system and the first clinical results achieved with this device in endovascular abdominal aortic aneurysm (AAA) repair. METHODS: From November 1993 to October 1996, 45 patients aged 60 to 86 years underwent endoluminal exclusion of true AAAs (median diameter 60 mm) involving the common iliac arteries (median diameter 16 mm right and 15 mm left) using unilimb stent-grafts deployed with the Iancev-Malmö system. RESULTS: Six immediate conversions occurred in the beginning of the series due to endografts that were too short. Complications, including 2 inadvertent renal artery occlusions, 7 kinked grafts, 6 iliac artery dissections, and 3 perioccluder leaks, were prominent features in the first 15 patients. Five patients died in the postoperative period, four of whom were nonsurgical candidates. There were five significant stent-graft migrations: one 3 weeks after surgery due to mechanical injury of the proximal stent and four after 1 year owing to continuous dilation of a wide proximal neck, stent-graft placement in a conical, thrombus-lined proximal neck, and two instances of proximal extension separation from the main graft. Translumbar aneurysm perfusion required embolization in 3 patients. CONCLUSIONS: Despite early complications associated with a learning curve, exclusion of large AAAs using unilimb stent-grafts is feasible. Strict inclusion criteria are necessary in order to improve mortality among nonsurgical candidates and minimize the risk for late migration.

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PubMed1997

Changing aneurysmal morphology after endovascular grafting: relation to leakage or persistent perfusion.

PURPOSE: To relate changing abdominal aortic aneurysm (AAA) morphology after endovascular grafting to the presence of leakage, collateral perfusion, and other factors. METHODS: Thirty-five patients who underwent successful AAA endovascular grafting were evaluated. Self-expanding Z-stents and Dacron grafts were applied in bifurcated and aortomonoiliac systems. Postoperative diameter changes were calculated from repeated spiral computed tomographic scans, angiograms, and ultrasonic phase-locked echo-tracking scans during a median 6-month follow-up (interquartile range [IQR] 3 to 12). RESULTS: At 12 months, the diameters of completely excluded aneurysms had decreased 6 mm (IQR 2 to 11; p = 0.006). The proximal graft-anchoring stents had dilated 2 mm (IQR 0.5 to 3.3; p = 0.01). The aortic diameters immediately below the renal arteries but above the stents had not changed. Endoleakage and collateral perfusion (n = 13) were each associated with preserved aneurysm size and a 12 times higher risk of aneurysm dilation. After the leakage or the collateral perfusion had been treated, the aneurysm size decreased. Aneurysms with extensive intraluminal thrombi presented a reduced risk of leakage or perfusion. CONCLUSIONS: The diameters of endovascularly excluded AAAs decrease, except in cases of leakage or perfusion. Careful follow-up of patients with aortic endografts is necessary.

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