- Email: [email protected]
Renal Artery Pseudoaneurysm Following Laparoscopic Partial Nephrectomy
Laparoscopy and Robotics Renal Artery Pseudoaneurysm Following Laparoscopic Partial Nephrectomy Edan Y. Shapiro, A. Ari Hakimi, Elias S. Hyams, Jacob Cynamon, Michael Stifelman, and Reza Ghavamian OBJECTIVES METHODS
RESULTS
CONCLUSIONS
To present our experience with the management of renal artery pseudoaneurysms following laparoscopic partial nephrectomy (LPN). Our bi-institutional LPN database of 259 patients from July 2001 to April 2008 was queried for patients diagnosed with a postoperative renal artery pseudoaneurysm. Demographic data, perioperative course, complications, and follow-up studies in identified subjects were analyzed. Postembolization success was defined as symptomatic relief, resolution of hematuria, and a stable hematocrit and serum creatinine. We identified 6 patients (2.3%) who were diagnosed with a renal artery pseudoaneurysm after LPN. The mean age of our cohort was 61.2 years (49-76), mean operative time was 208 minutes (140-265), and mean estimated blood loss was 408 mL (50-800). Patients presented at a mean of 12.6 days (5-23) after the initial surgery. Five patients had gross hematuria and a decreased hematocrit, with 1 patient presenting with clinical symptoms of hypovolemia. The sixth patient was incidentally diagnosed. The diagnosis of a renal artery pseudoaneurysm was confirmed in all cases by angiography. Selective angioembolization was successfully performed in all patients. At a median follow-up of 8.3 months all patients (100%) remained without any evidence of recurrence. Although pseudoaneuryms are a rare postoperative complication of LPN, they are potentially life-threatening. Early identification and proper management can help reduce the potential morbidity associated with pseudoaneurysms. Our experience demonstrates the feasibility and supports the use of selective angioembolization as an excellent first-line option for patients who present with this form of delayed bleeding. UROLOGY 74: 819 – 824, 2009. © 2009 Elsevier Inc.
N
ephron-sparing surgery has emerged as an excellent option for the management of small renal cortical tumors. Elective partial nephrectomy has become the standard of care for patients with renal tumors ⱕ 4 cm in the setting of a normal contralateral kidney. Some authors have even advocated partial nephrectomy in this elective setting in appropriately selected patients with tumors up to 7 cm in size. Laparoscopic partial nephrectomy (LPN), has been shown to have equivalent functional and oncologic outcomes to open surgery, while affording the patient all the benefits of laparoscopy.1-3 Complications of LPN for the most part are comparable to open partial nephrectomy. However, in a recent large study from 3 centers of excellence,
MATERIAL AND METHODS
From the Department of Urology, Montefiore Medical Center, Bainbridge, Bronx, New York; Department of Urology, New York University Medical Center, New York, New York; and Department of Interventional Radiology, Montefiore Medical Center, Bainbridge, Bronx, New York Reprint requests: A. Ari Hakimi, M.D., Department of Urology, 3400 Bainbridge, Bronx, NY 10467. E-mail: [email protected] Submitted: December 30, 2008, accepted (with revisions): March 25, 2009
A total of 259 laparoscopic partial nephrectomies were performed between April 1999 and June 2008 at 2 major teaching institutions. The procedures were performed by two experienced laparoscopists (R.G. and M.S.). A transperitoneal approach was performed for all procedures with renal hilar control. The clinicopathologic, perioperative, and follow-up data for all patients were reviewed, and patients diagnosed with a de-
© 2009 Elsevier Inc. All Rights Reserved
hemorrhagic complications were significantly more frequent in LPN.2 Renal artery pseudoaneurysm is a serious complication of partial nephrectomy and typically requires selective angioembolization to control the bleeding. There are a limited number of reports describing the presentation and management of this complication.4-10 Although this complication occurs after both open and laparoscopic nephrectomy, herein, we present our experience with pseudoaneurysm after LPN, including the clinical presentation, angiographic findings, and outcomes after intervention.
0090-4295/09/$34.00 doi:10.1016/j.urology.2009.03.056
819
820
5* 23 13 7 23 5 12.6 N/A* 3 5 3 6 4 4.2 400 600 50 800 500 100 408 205 265 140 190 N/A 238 208 Exophytic Exophytic Exophytic Endophytic Endophytic Endophytic 3.0 1.7 2.5 2.2 2.3 2.7 2.7 L R L L L R M M M M F M 1 2 3 4 5 6 Mean
75 71 49 55 63 53 61.2
LOS EBL OT Location Tumor (cm) Side Age (y) Sex No. Patients
Table 1. Patient characteristics, treatment, and follow-up information
Six patients (2.3%) presented with delayed hemorrhage and their characteristics are presented in Table 1. No patient was on anticoagulation therapy, and none had any history of previous renal surgery. Mean body mass index (BMI) for this cohort was 33.2 (27-42), with a mean ASA score of 2.5 (2-3). Of note, a seventh patient presented with delayed hemorrhage due to an arteriovenous fistula (AVF). However, we excluded this patient from our analysis because AVF and pseudoaneurysm are separate entities with different etiologies and the focus of the article is on pseudoaneurysms. Four of the 6 tumors were exophytic, but had a major endophytic component and the remaining 2 were endophytically located near the renal hilum. All tumors were resected with entry into the collecting system. The collecting system was repaired and renorrhaphy was successfully completed in all cases with interrupted absorbable sutures placed over bolsters composed of fibrin-soaked Gelfoam and Surgicel. Argon beam coagulator was used as an adjunct to various hemostatic compounds at the surgeons’ discretion, including FloSeal (Baxter, Irvine, CA) and Tissel (Baxter). Although the mean EBL was 408 mL, no patients required intraoperative transfusions. There were no intraoperative complications or open conversions. Renal hilar control with clamping of both the artery and vein was used in 5 cases, with a mean ischemia time of 34 minutes (31-38). Five patients had a solitary lesion, which consisted of 4 clear cell RCC and 1 papillary-type RCC. The sixth patient had multiple lesions, consisting of papillary, clear cell, and oncocytoma on final pathology. After surgery, 5 patients were discharged from the hospital on mean postoperative day 4.2 (3-6), with a stable hematocrit and without evidence of gross hematuria or clinical signs of bleeding. The remaining patient presented while still in the hospital from the LPN. The
DOP
RESULTS
OT ⫽ operative time; EBL ⫽ estimated blood loss; LOS ⫽ length of initial hospital stay; DOP ⫽ day of presentation; Hct ⫽ hematocrit; uPRBC ⫽ units of packed red blood cells; Sx ⫽ symptoms. * This patient presented during his initial postoperative hospital stay before be discharged. † This patient was incidentally diagnosed with a pseudoaneurysm.
Angioembolization Angioembolization Angioembolization Angioembolization Angioembolization Angioembolization Decreasing Hct Gross heme, pain, dizziness Pain, hematuria, retention Hematuria None† Hematuria 8 2 3 0 0 0 4.3
uPRBC
Presenting Sx
Treatment
layed hemorrhage requiring intervention were identified. Demographic and disease characteristics were recorded from our confidential IRB-approved oncologic databases, including age, gender, history of previous renal surgery, and preoperative renal function. Tumor size, depth, and location were determined from preoperative cross-sectional imaging. Operative data were collected for each patient, including the American society of Anesthesia Physical Symptom (ASA-PS) class, estimated blood loss (EBL), operative time, requirement for blood transfusion, type of repair, and warm ischemia time. Length of hospital stay (LOS), postoperative renal function, and hematocrit were also documented. Records were reviewed for information regarding the presentation of the postoperative hemorrhage and subsequent management. Follow-up after definitive treatment consisted of office visits to assess for resolution of hematuria and overall improvement. Follow-up hemograms were obtained to determine postembolization hematocrit levels. Radiographic follow-up were performed on a subset of patients. Success was defined as a combination of symptomatic relief, clinical and/or radiographic absence of bleeding, and stable postembolization renal function.
UROLOGY 74 (4), 2009
Figure 1. Angiographic evidence of renal artery pseudoaneurysm (arrow) before and after angioembolization with coil (arrowhead). (A) Preembolization angiogram demonstrating classic pseudaneursym “blush”. (B) Coil embolization. (C) Post embolization angiogram demonstrating highly selective coiling.
Figure 2. Preoperative CT scan of a patient with exophytic posterior mass on left kidney (L), and subsequent postoperative scan indicating the presence of an active bleed (arrow) from the surgical bed (R). The classic CT findings of a pseudoaneurysm are a rounded arterial blush with free blood in the retroperitoneum.
initial presentation of the delayed hemorrhage occurred on mean postoperative day 12 (5-23). Five of the total patients (83%) presented with complaints of gross hematuria, including 2 patients complaining of flank pain, 1 of whom also had clinical signs of hypovolemia. The sixth patient was diagnosed incidentally with pseudoaneurysm on renal ultrasound performed for fever. At presentation, all patients had decreased hematocrits relative to the value at time of their hospital discharge (38.8% vs 25.7%). Three patients (50%) required blood transfusions, with a mean of 4.3 units transfused. Angiography was performed in all cases (Figs. 1A and B), and an attending interventional radiologist in all cases made a definitive diagnosis of pseudoaneurysm. Following the diagnosis, superselective embolization was performed with platinum microcoils (Fig. 1C). Five of the total patients had complete resolution of the pseudoaneurysm with no post-treatment complications or recurrences (Table 1). However, 1 patient developed recurrent gross hematuria 15 days after angioembolization, and was found to have 2 newly diagnosed pseudoaneurysms adjacent to the area of resection, both of which were successfully embolized. Of note, both new pseudoaneurysms were found to occur at a distal branch of the lower pole artery, whereas the initial site was from a branch of the midpole artery. At a mean follow-up of 8.3 months (1UROLOGY 74 (4), 2009
24), all 6 patients (100%) were free from recurrence, as documented on CT and/or MRA (Fig. 2).
COMMENT Hemorrhagic complications are well-known sequelae of LPN occurring in approximately 5%-10% of cases.11,12 The most common type of hemorrhage involves intraoperative and/or postoperative bleeding, occasionally necessitating transfusion. However, hemorrhage can also occur in the context of a pseudoaneurysm or an arteriovenous malformation. Although these entities have been reported following renal trauma and percutaneous procedures, they are not as well characterized in the partial nephrectomy literature, especially for LPN.13,14 Post-partial nephrectomy rates of pseudoaneurysm are 0.4%1.4%.4,5 Currently, only 25 reported cases are available in the partial nephrectomy literature, with 11 reported after LPN.4-10,15-18 The etiology of pseudoaneurysm is believed to be the direct result of injury to a segmental branch of the renal artery, leading to a collection of blood in the surrounding tissue that freely communicates with the intravascular space. The vascular compromise is initially controlled by a combination of decreased blood flow, coagulation, and a tamponading effect of the surrounding tissue, which 821
initially prevents hemorrhage. As these temporizing measures begin to degrade, and the patient becomes more active, the blood flow to this vessel increases and a collection of blood from the renal artery begins to accumulate in the extravascular space, facilitating the formation of the pseudoaneurysm. Blood can then extend and leak into the collecting system, thus causing gross hematuria. Singh and Gill5 have suggested 2 possible mechanisms for this complication. The first is due to inadvertent vessel injury that occurs during the extirpation of the tumor, which mainly occurs with endophytically located tumors that require deep resection. The second is from a suture placed through a vessel during the reapproximation of the renal parenchyma. These iatrogenic injuries may not be initially noticed in the operating room, with patients presenting in a delayed fashion.4,5 The natural history of pseudoaneurysm ranges from spontaneous resolution to acute rupture. By far, the most common presentation is gross hematuria. Patients are often clinically stable and can present with nonspecific symptoms including flank pain, hypertension, and worsening lower urinary tract symptoms. A high index of suspicion in warranted following any surgical procedure that violates the renal parenchyma, especially in patients presenting with flank pain on the side of surgery and with gross hematuria. Patients usually present in the first few weeks after surgery, although the published studies report presentations ranging from as few as 1 day to 5 months postoperatively.4,7,15 After a pseudoaneurysm is suspected, radiographic evaluation is warranted. Arteriography remains the goldstandard diagnostic tool, although multiplanar contrastenhanced CT and MRA are suitable alternatives. Pseudoaneurysm appears as a focal area of high attenuation, with a similar enhancement to the adjacent vessels. The advantage of CT and MR imaging is that these modalities not only diagnose pseudoaneurysms but can also detect other possible intra-abdominal pathologies that may be responsible for the presenting symptoms. A three-dimensional reconstruction can be useful for differentiating a pseudoaneurysm from urinoma, which may, at times, be difficult to distinguish from one another.18 In our series, 3 patients had persistent hematuria despite conservative treatment with blood transfusions, whereas 2 patients were taken directly to angiography upon diagnosis by MRA. Unlike other reports, all patients presented at least 1 week after the initial surgery, at a mean time of 2 weeks postoperatively. Interestingly, the sixth patient had no signs or symptoms of a delayed bleed. This patient was seen by a urologist for a febrile urinary tract infection and underwent an office renal sonogram that was suspicious for a renal artery pseudoaneurysm (RAP). This is only the second reported case of pseudoaneurysm in an asymptomatic patient.4 The significance of asymptomatic pseudoaneurysms is unclear and their management is controversial. Pseudoaneurysm is likely more common than is recognized, particularly 822
with a growing willingness to treat endophytic tumors with LPN. However, only the subset that develop symptoms and have the relevant imaging will be diagnosed. Although 1 patient in our cohort presented with an AVF, this patient was not included in our cohort because AVF is a unique entity and we chose to focus primarily on the presentation and management of pseudoaneurysms. In contrast to the mechanism of pseudoaneurysm formation, arteriovenous fistulae occur from injury to arteries and veins in close proximity, allowing blood to flow from a high-pressure arterial system to the venous system without tamponade of the surrounding parenchyma. The angiographic findings of these 2 entities also differ. For arteriovenous fistulae, arteriography demonstrates injection of contrast in the artery that promptly results in the presence of contrast in the venous system, unlike the round configuration seen with pseudoaneurysms. Our analysis here was therefore limited to patients presenting with a postoperative pseudoaneurysm. All patients in our cohort were treated with selective angioembolization using microcoils. This intervention is ideal for focally isolating the pseudoaneurysm while preventing a significant decrease in renal vascularization, thereby preserving surrounding nephrons. Angioembolization has been shown to result in stable long-term renal function with serum creatinine levels returning to prebleeding baseline levels.19-21 All 6 patients in our study had stable post-treatment renal function. Complete resolution was seen in all 6 patients, with none developing recurrent pseudoaneurysm at the site of previous treatment. Interestingly, 1 patient developed 2 subsequent pseudoaneurysms, at a remote site, following the successful treatment of their initial pseudoaneurysm. This scenario has not been reported in the published studies and it remains unclear whether there were any host factors that predisposed this patient to vascular complications; both hematology and rheumatology evaluations yielded negative results in this patient. Although angioembolization is a highly successful, low-cost, and minimally invasive technique, some authors advocate for conservative management as the initial treatment in hemodynamically stable patients.4 The incidence of segmental RAP is low, relative to other post-LPN complications. In a review of 345 laparoscopic partial nephrectomies, the incidence of RAP was 1.7%, which was similar to our experience at a rate of 2.3%.5 A more recent review by Gill et al2 on 771 patients who underwent LPN showed an overall postoperative hemorrhage rate of 4.2%, with 5.8% of all patients requiring ⬎ 1 unit of blood postoperatively. Pseudoaneurysms were not mentioned specifically; however, 41% of these patients were managed conservatively, 31% required embolization, and the remaining 28% required re-exploration or a nephrectomy. The frequent requirement for measures beyond conservative treatment underscores the need for rigorous follow-up of these patients to UROLOGY 74 (4), 2009
enable early identification of vascular complications for which life-saving interventions might be offered. For our cohort, we were unable to discover any confounding factors that may have contributed to the delayed bleed. None of the patients were on anticoagulation medication, none had a history of coagulopathy, signs of platelet dysfunction, or thrombocytopenia. Finally, no patients received ketorolac or similar nonsteroidal anti-inflammatory agents postoperatively. Several intraoperative measures are indicated to prevent the formation of pseudoaneurysms. First, careful inspection of all vessels during tumor excision is warranted. Any obvious arteries should be ligated either by clipping or meticulous intracorporeal suturing. Renal capsular renorrhaphy sutures should not be placed too deeply to risk deep segmental branch injury. One continuous through and through suture motion is preferred, as multiple repositionings of the needle may cause arterial injury. In deep tumor resections, the tumor crater should be inspected and in the event of multiple segmental arterial transections, a hemostatic running intracorporeal suture at the crater should be employed with precise needle passes. Hemostatic agents such as FloSeal are used in the tumor crater with a rolled Surgical/Gelfoam cigar. Finally, meticulous inspection of the nephrectomy bed should be made after the renorrhaphy, especially after the abdomen is desufflated, to confirm adequate hemostasis. Hemostatic agents or the argon beam coagulator are then used as adjuncts in hemostasis. The aims of future studies include the identification of technical and patient risk factors that may predispose to pseudoaneurysm and delayed hemorrhage, and determining criteria that allow for safe observation of patients with gross hematuria, as well as whether treatment of incidentally diagnosed pseudoaneurysms is necessary. Not all patients with evidence of a delayed bleed require emergent intervention or intervention at all, depending on clinical status and underlying diagnosis. A low threshold should be maintained to proceed to angioembolization if intractable symptoms and/or clinical instability develop. This study has several limitations, inherent in its retrospective nature and small sample size. It is important to note that the true incidence of RAP may be larger than that currently reported because only patients with signs of acute bleeding, as well as 1 patient who was incidentally diagnosed, were imaged. If all patients undergoing LPN were routinely imaged postoperatively, we would expect to see a greater percentage of vascular abnormalities including pseudoaneurysm.
entity and provides excellent results with maximal renal preservation. References 1. McDougall E, Clayman R, Chandhoke P, et al. Laparoscopic partial nephrectomy in the pig model. J Urol. 1993;149:1633-1636. 2. Gill I, Kavoussi L, Lane B, et al. Comparison of 1,800 laparoscopic and open partial nephrectomies for single renal tumors. J Urol. 2007;178:41-46. 3. Dash A, Vickers A, Schachter L, et al. Comparison of outcomes in elective partial vs radical nephrectomy for clear cell renal cell carcinoma of 4-7 cm. BJU Int. 2006;97:939-945. 4. Albani J, Novick A. Renal artery pseudoaneurysm after partial nephrectomy: three case reports and a literature review. Urology. 2003;62:227-231. 5. Singh D, Gill I. Renal artery pseudoaneurysm following laparoscopic partial nephrectomy. J Urol. 2005;174:2256-2259. 6. Wright J, Porter J. Renal artery pseudoaneurysm after laparoscopic partial nephrectomy. Urology. 2005;66:1109. 7. Cohenpour M, Strauss S, Gottlieb P, et al. Pseudoaneurysm of the renal artery following partial nephrectomy: imaging findings and coil embolization. Clin Radiol. 2007;62:1104-1109. 8. Shigeta M, Mita K, Shoji K, et al. Renal artery pseudoaneurysm occurring after laparoscopic partial nephrectomy. Urol Int. 2008; 80:332-334. 9. Uberoi J, Badwan K, Wang D. Renal-artery pseudoaneurysm after laparoscopic partial nephrectomy. J Endourol. 2007;21:330-333. 10. Zorn K, Starks C, Gofrit O, et al. Embolization of renal-artery pseudoaneurysm after laparoscopic partial nephrectomy for angiomyolipoma: case report and literature review. J Endourol. 2007;21: 763-768. 11. Simmons M, Gill I. Decreased complications of contemporary laparoscopic partial nephrectomy: use of a standardized reporting system. J Urol. 2007;177:2067-2073. 12. Ramani A, Desai M, Steinberg A, et al. Complications of laparoscopic partial nephrectomy in 200 cases. J Urol. 2005;173:42-47. 13. Kessaris D, Bellman G, Pardalidis N, et al. Management of hemorrhage after percutaneous renal surgery. J Urol. 1995;153:604-608. 14. Swana H, Cohn S, Burns G, et al. Renal artery pseudoaneurysm after blunt abdominal trauma: case report and literature review. J Trauma. 1996;40:459-461. 15. Rezvani A, Ward J, Lavengood RJ. Intrarenal aneurysm following partial nephrectomy. Urology. 1973;2:286-288. 16. Chatziioannou A, Mourikis D, Awad M, et al. Embolization of a segmental renal artery pseudoaneurysm after partial nephrectomy in a solitary kidney. Urol Int. 2000;64:223-225. 17. Parsons J, Schoenberg M. Renal artery pseudoaneurysm occurring after partial nephrectomy. Urology. 2001;58:105. 18. Moore C, Rozen S, Fishman E. Two cases of pseudoaneurysm of the renal artery following laparoscopic partial nephrectomy for renal cell carcinoma: CT angiographic evaluation. Emerg Radiol. 2004; 10:193-196. 19. Miyazaki T, Saitoh R, Doi T, et al. Embolization of a pseudoaneurysm in the transplanted kidney. AJR. 1998;171:1617-1618. 20. Bui B, Oliva V, Péloquin F, et al. Correction of deteriorating renal function by superselective embolization of an arcuate renal artery pseudoaneurysm. J Urol. 1994;152:2087-2088. 21. Chatziioannou A, Brountzos E, Primetis E, et al. Effects of superselective embolization for renal vascular injuries on renal parenchyma and function. Eur J Vasc Endovasc Surg. 2004;28:201-206.
CONCLUSIONS Although delayed hemorrhage due to RAPs is a rare event, it is potentially life-threatening. It must be considered in any patient who presents with gross hematuria or other signs of bleeding after LPN. Selective angioembolization is a safe and efficacious treatment for this UROLOGY 74 (4), 2009
EDITORIAL COMMENT Despite apparent, appropriate patient-selection and surgical technique, hemorrhage associated with laparoscopic partial nephrectomy (LPN) remains significant, with rates as high as 10% and transfusion rates as high as 15%. A significant percentage of 823
RESULTS
CONCLUSIONS
To present our experience with the management of renal artery pseudoaneurysms following laparoscopic partial nephrectomy (LPN). Our bi-institutional LPN database of 259 patients from July 2001 to April 2008 was queried for patients diagnosed with a postoperative renal artery pseudoaneurysm. Demographic data, perioperative course, complications, and follow-up studies in identified subjects were analyzed. Postembolization success was defined as symptomatic relief, resolution of hematuria, and a stable hematocrit and serum creatinine. We identified 6 patients (2.3%) who were diagnosed with a renal artery pseudoaneurysm after LPN. The mean age of our cohort was 61.2 years (49-76), mean operative time was 208 minutes (140-265), and mean estimated blood loss was 408 mL (50-800). Patients presented at a mean of 12.6 days (5-23) after the initial surgery. Five patients had gross hematuria and a decreased hematocrit, with 1 patient presenting with clinical symptoms of hypovolemia. The sixth patient was incidentally diagnosed. The diagnosis of a renal artery pseudoaneurysm was confirmed in all cases by angiography. Selective angioembolization was successfully performed in all patients. At a median follow-up of 8.3 months all patients (100%) remained without any evidence of recurrence. Although pseudoaneuryms are a rare postoperative complication of LPN, they are potentially life-threatening. Early identification and proper management can help reduce the potential morbidity associated with pseudoaneurysms. Our experience demonstrates the feasibility and supports the use of selective angioembolization as an excellent first-line option for patients who present with this form of delayed bleeding. UROLOGY 74: 819 – 824, 2009. © 2009 Elsevier Inc.
N
ephron-sparing surgery has emerged as an excellent option for the management of small renal cortical tumors. Elective partial nephrectomy has become the standard of care for patients with renal tumors ⱕ 4 cm in the setting of a normal contralateral kidney. Some authors have even advocated partial nephrectomy in this elective setting in appropriately selected patients with tumors up to 7 cm in size. Laparoscopic partial nephrectomy (LPN), has been shown to have equivalent functional and oncologic outcomes to open surgery, while affording the patient all the benefits of laparoscopy.1-3 Complications of LPN for the most part are comparable to open partial nephrectomy. However, in a recent large study from 3 centers of excellence,
MATERIAL AND METHODS
From the Department of Urology, Montefiore Medical Center, Bainbridge, Bronx, New York; Department of Urology, New York University Medical Center, New York, New York; and Department of Interventional Radiology, Montefiore Medical Center, Bainbridge, Bronx, New York Reprint requests: A. Ari Hakimi, M.D., Department of Urology, 3400 Bainbridge, Bronx, NY 10467. E-mail: [email protected] Submitted: December 30, 2008, accepted (with revisions): March 25, 2009
A total of 259 laparoscopic partial nephrectomies were performed between April 1999 and June 2008 at 2 major teaching institutions. The procedures were performed by two experienced laparoscopists (R.G. and M.S.). A transperitoneal approach was performed for all procedures with renal hilar control. The clinicopathologic, perioperative, and follow-up data for all patients were reviewed, and patients diagnosed with a de-
© 2009 Elsevier Inc. All Rights Reserved
hemorrhagic complications were significantly more frequent in LPN.2 Renal artery pseudoaneurysm is a serious complication of partial nephrectomy and typically requires selective angioembolization to control the bleeding. There are a limited number of reports describing the presentation and management of this complication.4-10 Although this complication occurs after both open and laparoscopic nephrectomy, herein, we present our experience with pseudoaneurysm after LPN, including the clinical presentation, angiographic findings, and outcomes after intervention.
0090-4295/09/$34.00 doi:10.1016/j.urology.2009.03.056
819
820
5* 23 13 7 23 5 12.6 N/A* 3 5 3 6 4 4.2 400 600 50 800 500 100 408 205 265 140 190 N/A 238 208 Exophytic Exophytic Exophytic Endophytic Endophytic Endophytic 3.0 1.7 2.5 2.2 2.3 2.7 2.7 L R L L L R M M M M F M 1 2 3 4 5 6 Mean
75 71 49 55 63 53 61.2
LOS EBL OT Location Tumor (cm) Side Age (y) Sex No. Patients
Table 1. Patient characteristics, treatment, and follow-up information
Six patients (2.3%) presented with delayed hemorrhage and their characteristics are presented in Table 1. No patient was on anticoagulation therapy, and none had any history of previous renal surgery. Mean body mass index (BMI) for this cohort was 33.2 (27-42), with a mean ASA score of 2.5 (2-3). Of note, a seventh patient presented with delayed hemorrhage due to an arteriovenous fistula (AVF). However, we excluded this patient from our analysis because AVF and pseudoaneurysm are separate entities with different etiologies and the focus of the article is on pseudoaneurysms. Four of the 6 tumors were exophytic, but had a major endophytic component and the remaining 2 were endophytically located near the renal hilum. All tumors were resected with entry into the collecting system. The collecting system was repaired and renorrhaphy was successfully completed in all cases with interrupted absorbable sutures placed over bolsters composed of fibrin-soaked Gelfoam and Surgicel. Argon beam coagulator was used as an adjunct to various hemostatic compounds at the surgeons’ discretion, including FloSeal (Baxter, Irvine, CA) and Tissel (Baxter). Although the mean EBL was 408 mL, no patients required intraoperative transfusions. There were no intraoperative complications or open conversions. Renal hilar control with clamping of both the artery and vein was used in 5 cases, with a mean ischemia time of 34 minutes (31-38). Five patients had a solitary lesion, which consisted of 4 clear cell RCC and 1 papillary-type RCC. The sixth patient had multiple lesions, consisting of papillary, clear cell, and oncocytoma on final pathology. After surgery, 5 patients were discharged from the hospital on mean postoperative day 4.2 (3-6), with a stable hematocrit and without evidence of gross hematuria or clinical signs of bleeding. The remaining patient presented while still in the hospital from the LPN. The
DOP
RESULTS
OT ⫽ operative time; EBL ⫽ estimated blood loss; LOS ⫽ length of initial hospital stay; DOP ⫽ day of presentation; Hct ⫽ hematocrit; uPRBC ⫽ units of packed red blood cells; Sx ⫽ symptoms. * This patient presented during his initial postoperative hospital stay before be discharged. † This patient was incidentally diagnosed with a pseudoaneurysm.
Angioembolization Angioembolization Angioembolization Angioembolization Angioembolization Angioembolization Decreasing Hct Gross heme, pain, dizziness Pain, hematuria, retention Hematuria None† Hematuria 8 2 3 0 0 0 4.3
uPRBC
Presenting Sx
Treatment
layed hemorrhage requiring intervention were identified. Demographic and disease characteristics were recorded from our confidential IRB-approved oncologic databases, including age, gender, history of previous renal surgery, and preoperative renal function. Tumor size, depth, and location were determined from preoperative cross-sectional imaging. Operative data were collected for each patient, including the American society of Anesthesia Physical Symptom (ASA-PS) class, estimated blood loss (EBL), operative time, requirement for blood transfusion, type of repair, and warm ischemia time. Length of hospital stay (LOS), postoperative renal function, and hematocrit were also documented. Records were reviewed for information regarding the presentation of the postoperative hemorrhage and subsequent management. Follow-up after definitive treatment consisted of office visits to assess for resolution of hematuria and overall improvement. Follow-up hemograms were obtained to determine postembolization hematocrit levels. Radiographic follow-up were performed on a subset of patients. Success was defined as a combination of symptomatic relief, clinical and/or radiographic absence of bleeding, and stable postembolization renal function.
UROLOGY 74 (4), 2009
Figure 1. Angiographic evidence of renal artery pseudoaneurysm (arrow) before and after angioembolization with coil (arrowhead). (A) Preembolization angiogram demonstrating classic pseudaneursym “blush”. (B) Coil embolization. (C) Post embolization angiogram demonstrating highly selective coiling.
Figure 2. Preoperative CT scan of a patient with exophytic posterior mass on left kidney (L), and subsequent postoperative scan indicating the presence of an active bleed (arrow) from the surgical bed (R). The classic CT findings of a pseudoaneurysm are a rounded arterial blush with free blood in the retroperitoneum.
initial presentation of the delayed hemorrhage occurred on mean postoperative day 12 (5-23). Five of the total patients (83%) presented with complaints of gross hematuria, including 2 patients complaining of flank pain, 1 of whom also had clinical signs of hypovolemia. The sixth patient was diagnosed incidentally with pseudoaneurysm on renal ultrasound performed for fever. At presentation, all patients had decreased hematocrits relative to the value at time of their hospital discharge (38.8% vs 25.7%). Three patients (50%) required blood transfusions, with a mean of 4.3 units transfused. Angiography was performed in all cases (Figs. 1A and B), and an attending interventional radiologist in all cases made a definitive diagnosis of pseudoaneurysm. Following the diagnosis, superselective embolization was performed with platinum microcoils (Fig. 1C). Five of the total patients had complete resolution of the pseudoaneurysm with no post-treatment complications or recurrences (Table 1). However, 1 patient developed recurrent gross hematuria 15 days after angioembolization, and was found to have 2 newly diagnosed pseudoaneurysms adjacent to the area of resection, both of which were successfully embolized. Of note, both new pseudoaneurysms were found to occur at a distal branch of the lower pole artery, whereas the initial site was from a branch of the midpole artery. At a mean follow-up of 8.3 months (1UROLOGY 74 (4), 2009
24), all 6 patients (100%) were free from recurrence, as documented on CT and/or MRA (Fig. 2).
COMMENT Hemorrhagic complications are well-known sequelae of LPN occurring in approximately 5%-10% of cases.11,12 The most common type of hemorrhage involves intraoperative and/or postoperative bleeding, occasionally necessitating transfusion. However, hemorrhage can also occur in the context of a pseudoaneurysm or an arteriovenous malformation. Although these entities have been reported following renal trauma and percutaneous procedures, they are not as well characterized in the partial nephrectomy literature, especially for LPN.13,14 Post-partial nephrectomy rates of pseudoaneurysm are 0.4%1.4%.4,5 Currently, only 25 reported cases are available in the partial nephrectomy literature, with 11 reported after LPN.4-10,15-18 The etiology of pseudoaneurysm is believed to be the direct result of injury to a segmental branch of the renal artery, leading to a collection of blood in the surrounding tissue that freely communicates with the intravascular space. The vascular compromise is initially controlled by a combination of decreased blood flow, coagulation, and a tamponading effect of the surrounding tissue, which 821
initially prevents hemorrhage. As these temporizing measures begin to degrade, and the patient becomes more active, the blood flow to this vessel increases and a collection of blood from the renal artery begins to accumulate in the extravascular space, facilitating the formation of the pseudoaneurysm. Blood can then extend and leak into the collecting system, thus causing gross hematuria. Singh and Gill5 have suggested 2 possible mechanisms for this complication. The first is due to inadvertent vessel injury that occurs during the extirpation of the tumor, which mainly occurs with endophytically located tumors that require deep resection. The second is from a suture placed through a vessel during the reapproximation of the renal parenchyma. These iatrogenic injuries may not be initially noticed in the operating room, with patients presenting in a delayed fashion.4,5 The natural history of pseudoaneurysm ranges from spontaneous resolution to acute rupture. By far, the most common presentation is gross hematuria. Patients are often clinically stable and can present with nonspecific symptoms including flank pain, hypertension, and worsening lower urinary tract symptoms. A high index of suspicion in warranted following any surgical procedure that violates the renal parenchyma, especially in patients presenting with flank pain on the side of surgery and with gross hematuria. Patients usually present in the first few weeks after surgery, although the published studies report presentations ranging from as few as 1 day to 5 months postoperatively.4,7,15 After a pseudoaneurysm is suspected, radiographic evaluation is warranted. Arteriography remains the goldstandard diagnostic tool, although multiplanar contrastenhanced CT and MRA are suitable alternatives. Pseudoaneurysm appears as a focal area of high attenuation, with a similar enhancement to the adjacent vessels. The advantage of CT and MR imaging is that these modalities not only diagnose pseudoaneurysms but can also detect other possible intra-abdominal pathologies that may be responsible for the presenting symptoms. A three-dimensional reconstruction can be useful for differentiating a pseudoaneurysm from urinoma, which may, at times, be difficult to distinguish from one another.18 In our series, 3 patients had persistent hematuria despite conservative treatment with blood transfusions, whereas 2 patients were taken directly to angiography upon diagnosis by MRA. Unlike other reports, all patients presented at least 1 week after the initial surgery, at a mean time of 2 weeks postoperatively. Interestingly, the sixth patient had no signs or symptoms of a delayed bleed. This patient was seen by a urologist for a febrile urinary tract infection and underwent an office renal sonogram that was suspicious for a renal artery pseudoaneurysm (RAP). This is only the second reported case of pseudoaneurysm in an asymptomatic patient.4 The significance of asymptomatic pseudoaneurysms is unclear and their management is controversial. Pseudoaneurysm is likely more common than is recognized, particularly 822
with a growing willingness to treat endophytic tumors with LPN. However, only the subset that develop symptoms and have the relevant imaging will be diagnosed. Although 1 patient in our cohort presented with an AVF, this patient was not included in our cohort because AVF is a unique entity and we chose to focus primarily on the presentation and management of pseudoaneurysms. In contrast to the mechanism of pseudoaneurysm formation, arteriovenous fistulae occur from injury to arteries and veins in close proximity, allowing blood to flow from a high-pressure arterial system to the venous system without tamponade of the surrounding parenchyma. The angiographic findings of these 2 entities also differ. For arteriovenous fistulae, arteriography demonstrates injection of contrast in the artery that promptly results in the presence of contrast in the venous system, unlike the round configuration seen with pseudoaneurysms. Our analysis here was therefore limited to patients presenting with a postoperative pseudoaneurysm. All patients in our cohort were treated with selective angioembolization using microcoils. This intervention is ideal for focally isolating the pseudoaneurysm while preventing a significant decrease in renal vascularization, thereby preserving surrounding nephrons. Angioembolization has been shown to result in stable long-term renal function with serum creatinine levels returning to prebleeding baseline levels.19-21 All 6 patients in our study had stable post-treatment renal function. Complete resolution was seen in all 6 patients, with none developing recurrent pseudoaneurysm at the site of previous treatment. Interestingly, 1 patient developed 2 subsequent pseudoaneurysms, at a remote site, following the successful treatment of their initial pseudoaneurysm. This scenario has not been reported in the published studies and it remains unclear whether there were any host factors that predisposed this patient to vascular complications; both hematology and rheumatology evaluations yielded negative results in this patient. Although angioembolization is a highly successful, low-cost, and minimally invasive technique, some authors advocate for conservative management as the initial treatment in hemodynamically stable patients.4 The incidence of segmental RAP is low, relative to other post-LPN complications. In a review of 345 laparoscopic partial nephrectomies, the incidence of RAP was 1.7%, which was similar to our experience at a rate of 2.3%.5 A more recent review by Gill et al2 on 771 patients who underwent LPN showed an overall postoperative hemorrhage rate of 4.2%, with 5.8% of all patients requiring ⬎ 1 unit of blood postoperatively. Pseudoaneurysms were not mentioned specifically; however, 41% of these patients were managed conservatively, 31% required embolization, and the remaining 28% required re-exploration or a nephrectomy. The frequent requirement for measures beyond conservative treatment underscores the need for rigorous follow-up of these patients to UROLOGY 74 (4), 2009
enable early identification of vascular complications for which life-saving interventions might be offered. For our cohort, we were unable to discover any confounding factors that may have contributed to the delayed bleed. None of the patients were on anticoagulation medication, none had a history of coagulopathy, signs of platelet dysfunction, or thrombocytopenia. Finally, no patients received ketorolac or similar nonsteroidal anti-inflammatory agents postoperatively. Several intraoperative measures are indicated to prevent the formation of pseudoaneurysms. First, careful inspection of all vessels during tumor excision is warranted. Any obvious arteries should be ligated either by clipping or meticulous intracorporeal suturing. Renal capsular renorrhaphy sutures should not be placed too deeply to risk deep segmental branch injury. One continuous through and through suture motion is preferred, as multiple repositionings of the needle may cause arterial injury. In deep tumor resections, the tumor crater should be inspected and in the event of multiple segmental arterial transections, a hemostatic running intracorporeal suture at the crater should be employed with precise needle passes. Hemostatic agents such as FloSeal are used in the tumor crater with a rolled Surgical/Gelfoam cigar. Finally, meticulous inspection of the nephrectomy bed should be made after the renorrhaphy, especially after the abdomen is desufflated, to confirm adequate hemostasis. Hemostatic agents or the argon beam coagulator are then used as adjuncts in hemostasis. The aims of future studies include the identification of technical and patient risk factors that may predispose to pseudoaneurysm and delayed hemorrhage, and determining criteria that allow for safe observation of patients with gross hematuria, as well as whether treatment of incidentally diagnosed pseudoaneurysms is necessary. Not all patients with evidence of a delayed bleed require emergent intervention or intervention at all, depending on clinical status and underlying diagnosis. A low threshold should be maintained to proceed to angioembolization if intractable symptoms and/or clinical instability develop. This study has several limitations, inherent in its retrospective nature and small sample size. It is important to note that the true incidence of RAP may be larger than that currently reported because only patients with signs of acute bleeding, as well as 1 patient who was incidentally diagnosed, were imaged. If all patients undergoing LPN were routinely imaged postoperatively, we would expect to see a greater percentage of vascular abnormalities including pseudoaneurysm.
entity and provides excellent results with maximal renal preservation. References 1. McDougall E, Clayman R, Chandhoke P, et al. Laparoscopic partial nephrectomy in the pig model. J Urol. 1993;149:1633-1636. 2. Gill I, Kavoussi L, Lane B, et al. Comparison of 1,800 laparoscopic and open partial nephrectomies for single renal tumors. J Urol. 2007;178:41-46. 3. Dash A, Vickers A, Schachter L, et al. Comparison of outcomes in elective partial vs radical nephrectomy for clear cell renal cell carcinoma of 4-7 cm. BJU Int. 2006;97:939-945. 4. Albani J, Novick A. Renal artery pseudoaneurysm after partial nephrectomy: three case reports and a literature review. Urology. 2003;62:227-231. 5. Singh D, Gill I. Renal artery pseudoaneurysm following laparoscopic partial nephrectomy. J Urol. 2005;174:2256-2259. 6. Wright J, Porter J. Renal artery pseudoaneurysm after laparoscopic partial nephrectomy. Urology. 2005;66:1109. 7. Cohenpour M, Strauss S, Gottlieb P, et al. Pseudoaneurysm of the renal artery following partial nephrectomy: imaging findings and coil embolization. Clin Radiol. 2007;62:1104-1109. 8. Shigeta M, Mita K, Shoji K, et al. Renal artery pseudoaneurysm occurring after laparoscopic partial nephrectomy. Urol Int. 2008; 80:332-334. 9. Uberoi J, Badwan K, Wang D. Renal-artery pseudoaneurysm after laparoscopic partial nephrectomy. J Endourol. 2007;21:330-333. 10. Zorn K, Starks C, Gofrit O, et al. Embolization of renal-artery pseudoaneurysm after laparoscopic partial nephrectomy for angiomyolipoma: case report and literature review. J Endourol. 2007;21: 763-768. 11. Simmons M, Gill I. Decreased complications of contemporary laparoscopic partial nephrectomy: use of a standardized reporting system. J Urol. 2007;177:2067-2073. 12. Ramani A, Desai M, Steinberg A, et al. Complications of laparoscopic partial nephrectomy in 200 cases. J Urol. 2005;173:42-47. 13. Kessaris D, Bellman G, Pardalidis N, et al. Management of hemorrhage after percutaneous renal surgery. J Urol. 1995;153:604-608. 14. Swana H, Cohn S, Burns G, et al. Renal artery pseudoaneurysm after blunt abdominal trauma: case report and literature review. J Trauma. 1996;40:459-461. 15. Rezvani A, Ward J, Lavengood RJ. Intrarenal aneurysm following partial nephrectomy. Urology. 1973;2:286-288. 16. Chatziioannou A, Mourikis D, Awad M, et al. Embolization of a segmental renal artery pseudoaneurysm after partial nephrectomy in a solitary kidney. Urol Int. 2000;64:223-225. 17. Parsons J, Schoenberg M. Renal artery pseudoaneurysm occurring after partial nephrectomy. Urology. 2001;58:105. 18. Moore C, Rozen S, Fishman E. Two cases of pseudoaneurysm of the renal artery following laparoscopic partial nephrectomy for renal cell carcinoma: CT angiographic evaluation. Emerg Radiol. 2004; 10:193-196. 19. Miyazaki T, Saitoh R, Doi T, et al. Embolization of a pseudoaneurysm in the transplanted kidney. AJR. 1998;171:1617-1618. 20. Bui B, Oliva V, Péloquin F, et al. Correction of deteriorating renal function by superselective embolization of an arcuate renal artery pseudoaneurysm. J Urol. 1994;152:2087-2088. 21. Chatziioannou A, Brountzos E, Primetis E, et al. Effects of superselective embolization for renal vascular injuries on renal parenchyma and function. Eur J Vasc Endovasc Surg. 2004;28:201-206.
CONCLUSIONS Although delayed hemorrhage due to RAPs is a rare event, it is potentially life-threatening. It must be considered in any patient who presents with gross hematuria or other signs of bleeding after LPN. Selective angioembolization is a safe and efficacious treatment for this UROLOGY 74 (4), 2009
EDITORIAL COMMENT Despite apparent, appropriate patient-selection and surgical technique, hemorrhage associated with laparoscopic partial nephrectomy (LPN) remains significant, with rates as high as 10% and transfusion rates as high as 15%. A significant percentage of 823