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ORIGINAL ARTICLE
Year : 2022 | Volume
: 9
| Issue : 5 | Page : 370-376
New classification for juxta renal aortoiliac occlusion-based on imaging for safe clamping and contemporary surgical management results
Ajay Savlania1, Venkata Vineeth Vaddavalli1, Sriharsha Balraj1, Prashant Jain1, Aswitha Ravi1, M Ananthakumar1, Arunanshu Behera1, Ujjwal Gorsi2, Lileshwar Kaman1
1 Department of General Surgery, Post Graduate Institute of Medical Education and Research, Chandigarh, India
2 Department of Radiodiagnosis, Post Graduate Institute of Medical Education and Research, Chandigarh, India
Correspondence Address:
Dr. Ajay Savlania
Department of General Surgery, Post Graduate Institute of Medical Education and Research, Chandigarh
India
Source of Support: None, Conflict of Interest: None
CheckDOI: 10.4103/ijves.ijves_62_22
Objectives: The objective is to decide the site of aortic clamping based on preoperative imaging and intraoperative findings and assess the outcomes on midterm follow-up in patients with juxtarenal aortoiliac occlusion (JRAIO) managed with aortic thromboendarterectomy and bypass grafting. Methods: Forty patients (39 males and one female) with JRAIO were managed with aortobifemoral bypass (ABFB). Two patients required concomitant superior mesenteric artery (SMA) bypass. The aortic clamping site was inter-renal, suprarenal, or supra-celiac, depending on the extent of thrombus relative to the renal artery and SMA ostia. We compared serum creatinine levels with renal ischemic time in the postoperative period. At the mean follow-up of 26.7 months, patients were assessed for graft patency, limb salvage, and survival rate. Results: The mean age of patients was 53.9 years, and 97.5% of patients were heavy smokers. Of the total patients, inter-renal clamping was done in 12.5%, suprarenal clamping in 70%, and supra-celiac clamping in 17.5%. Perioperative morbidity and mortality were 22.5% and 5%, respectively. Five patients with renal ischemic time ≥20 min developed acute kidney injury, showing a significant positive correlation (r = 0.465; P < 0.0001) with clamp time. Postoperative mean serum creatinine values also showed a significant difference (P = 0.0001) between <20 and ≥20 min groups. At follow-up, graft patency and limb salvage rates were 100%, and the survival rate was 97.4%. Conclusion: The risk of atheroembolic renal ischemia in ABFB for JRAIO can be lowered by good preoperative planning and safe intraoperative clamping technique, based on a simple classification for aortic clamping.
Keywords: Acute kidney injury, aortic endarterectomy, aortobifemoral bypass, juxtarenal aortoiliac occlusion, suprarenal aortic clamping
Atherosclerotic occlusive disease involving the abdominal aorta and iliac arteries is a common therapeutic challenge faced by most vascular surgeons. Patients with total occlusion of infrarenal aorta account only for 3%–8.5% of those with aortoiliac occlusive disease (AIOD).[1],[2],[3] The trans-Atlantic intersociety classification (TASC) of AIOD has confined infrarenal aortic occlusion among type D lesions.[4]
Two different patterns of AIOD can be identified based on the extent of atherosclerosis and symptomatology: distal and proximal or juxtarenal. Distal variety causes varying degrees of claudication and critical limb ischemia. In contrast, the juxtarenal type of AIOD also propagates proximally, leading to visceral artery stenosis or occlusion, consequent renal failure and intestinal ischemia, and even acute spinal cord ischemia and paraplegia.[4]
With the advancement and increasing experience in endovascular techniques, efforts are being made to treat juxta-renal aortoiliac occlusion (JRAIO) endovascularly, but no significant data support its durability.[5] Aortic thromboendarterectomy with bypass grafting is still the gold standard for managing this advanced AIOD pathology,[4] but in current literature, there is no detailed description regarding different patterns of the proximal extent of thrombus which can influence clamping and type of thrombus which can influence the duration of clamping. This study was conducted to assess the imaging patterns and intraoperative character of thrombus in JRAIO and its effect on decision-making regarding the aortic clamping site, duration of clamping, and its effect on postoperative renal functions.
MethodsA total of 40 patients having JRAIO who require aorto-bifemoral bypass (ABFB) surgery, were included in this study after taking written informed consent from all the patients from January 2016 to July 2020 at a Tertiary Care Center in Northern India. The study was conducted after obtaining the Institutional Ethical Clearance (NK/4820/MS/089). JRAIO was defined as occlusion of aorta extending cephalad approaching the level of the lowest renal artery. The patterns of the proximal extent of thrombus, involvement of the viscero-renal arteries, and the site of intraoperative aortic clamping were evaluated prospectively. These patients had either severe claudication affecting their quality of life or chronic limb-threatening ischemia (CLTI). Patients with poor cardiac function (assessed with 12 lead electrocardiogram, echocardiography, and stress thallium perfusion study in selected patients) or poor pulmonary functional status and deemed unfit to undergo ABFB surgery were not included in the study. These patients were managed with extra-anatomical bypass procedures or medical management. All the patients planned for surgery underwent preoperative clinical assessment with the examination of peripheral pulses, ankle-brachial index (ABI) measurement, renal function test, liver function test, hemogram, coagulation profile, and computed tomography (CT) angiography (CTA) of the abdominal aorta and bilateral lower limbs [Figure 1].
Figure 1: Computed tomography angiogram-based classification for the purpose of deciding safe clamp space for the surgical management of JRAIO. N is a number of patients followed by percentage. Type I, juxtarenal thrombus reaching the base of one renal artery, and there is a space for inter-renal clamping. Type II, Juxta renal thrombus going to the base of both renal arteries, or one of the renal arteries is occluded by lesion and there is space for suprarenal aortic clamping. Type III, no safe suprarenal clamp space due to eccentric thrombus progression cranially on the posterior or anterior wall of aorta or SMA occluded by thrombus. These patients require supra-celiac aortic clamping. JRAIO: Juxtarenal aortoiliac occlusion, SMA: Superior mesenteric arterySurgical technique
All the patients included in this study underwent aortic thromboendarterectomy and ABFB grafting through midline laparotomy and transperitoneal approach. The parietal peritoneum overlying infrarenal aorta was incised after releasing the ligament of the Treitz. After this, the left renal vein was mobilized and retracted caudally but never divided to achieve adequate and safe access to the superior mesenteric artery (SMA) and renal artery-bearing segment of the aorta [Figure 2]a. The site of aortic clamping was decided based on the proximal extent of the thrombus and the involvement of viscero-renal arteries. Supra-celiac aorta was dissected and exposed in case thrombus and plaque extent warranted supra celiac aortic control, or there was no safe clamping space between SMA and renal arteries due to their very close ostia [Figure 1]. After 1 mg/kg of heparin injection, clamping of one or bilateral renal arteries was mandatory with bulldog soft clamps before inter/suprarenal aortic clamp placement to reduce the risk of atheroembolization. The aortic clamping was inter-renal, suprarenal, or supraceliac as mandated by the extent of thrombus in relation to renal and SMA [Figure 1].
Figure 2: Intraoperative pictures showing the surgical technique of ABFB in JRAIO. (a) Intraoperative picture showing retroperitoneal structures–left renal vein looped and retracted caudally, renal arteries and SMA dissected neatly for safe suprarenal clamping (arrows). Green and yellow arrow depicting right and left renal arteries, black arrow showing SMA. (b) Infrarenal aorta transacted 2 cm below renal arteries after clamping renal arteries and suprarenal aorta. (c) Intraoperative picture showing end-to-end anastomosis of the aorta with a coated Polyester graft. (d) Intraoperative picture showing retrograde bypass from the left limb of ABFB graft to SMA. SMA: Superior mesenteric artery, JRAIO: Juxtarenal aortoiliac occlusion, ABFB: Aortobifemoral bypassAfter this, the aorta was transected 1.5–2 cm below the lowest renal artery origin, and an adequate thromboendarterectomy of the infrarenal aorta was done [Figure 2]b. The bulldog clamps were then released from renal arteries to check the back bleed and flush out debris from their lumen. Suprarenal, inter-renal clamp, or supra celiac clamp was then transferred to an infrarenal position, and blood flow was restored to visceral and renal arteries. Then, conventional ABFB was performed [Figure 2]c with proximal anastomosis in an end-to-end fashion and distal anastomosis with bilateral common femoral arteries in an end-to-side manner. All patients received mannitol diuresis (20 g/100 ml) before renal artery clamping intraoperatively. We used coated polyester grafts of size 16 mm × 8 mm or 14 mm × 7 mm in all patients. In addition, two patients presented with features of chronic mesenteric ischemia due to SMA occlusion. In these patients, we did a simultaneous retrograde bypass from one of the limbs of the primary ABFB graft [Figure 2]d. Inferior mesenteric artery reimplantation was not done in any of the patients. Blood and blood products were used intraoperatively and postoperatively based on blood loss and the patient's hemodynamics.
Postoperative monitoring
Postoperatively, patients were assessed for lower limb pulses, urine output, and serum creatinine levels, cardiac biomarkers such as Troponin T/I and Creatine kinase-MB (CK-MB), wound status, and if deemed fit in all aspects, were considered for discharge after advising regular follow-up. Patients with serum creatinine values showing a >50% increase above the preoperative levels or low urine output (<0.5 ml/kg/h for >6 h) were labeled as having acute kidney injury (AKI) as per AKI Network 2007 definition.[6],[7] In the postoperative period, all patients were prescribed antiplatelet drugs and statins. Antihypertensive, insulin, and oral hypoglycemic drugs were given as per indication.
Follow-up and outcome assessment
Follow-up of patients was scheduled at 1 month, then every 3 months for the 1st year, 6-monthly in the 2nd year, and annually thereafter. During the follow-up, all patients were assessed by clinical examination, ABI, and Duplex ultrasonography. CTA was planned only for any suspected graft stenosis or occlusion, pseudoaneurysm formation, or progression of the distal disease.
Endpoint definitions for outcome assessment were adopted from the Society for Vascular Surgery Working Group for the development of objective performance goals in 2009. Safety outcomes included major adverse cardiovascular events and major adverse limb events within 30 days of surgery. In addition, perioperative morbidity (within 30 days), graft patency, and survival rate at 2 years' follow-up were also calculated.
Statistical analysis
All the data were recorded in an electronic case record form, and statistical analysis was done in Microsoft Excel and SPSS version software 17 (SPSS Inc, Floor Chicago, IL, USA). All categorical variables were recorded as percentages and continuous variables as means. Means were compared using an unpaired Student's t-test. The correlation between two variables was determined using Pearson's correlation coefficient (r). The level of significance was kept at P < 0.05.
ResultsA total of 40 patients with JRAIO underwent ABFB surgery. Their demographic details and symptom profiles are described in [Table 1]. On evaluating risk factors and comorbidities, 39/40 participants (97.5%) were chronic smokers. Seventeen patients (42.5%) had a history of hypertension, and 14 (35%) had diabetes mellitus. A history of coronary artery disease was identified in eight patients (20%) [Table 1]. None of the patients had preoperative evidence of renal insufficiency, defined as a serum creatinine level >1.6 mg/dl.
On preoperative CT angiogram evaluation, JRAIO with occlusion of the unilateral renal artery was found in two patients (5%), SMA occlusion in two patients (5%), and normal renal functions in all the patients. Eight patients (20%) had tandem stenotic and occlusive lesions in the profunda femoris artery, and six patients (15%) had femoropopliteal disease and tibial vessel disease. The profundoplasty was done in eight patients (20%), and sequential femoropopliteal bypass with reversed saphenous vein graft was done in four patients (10%) during the same procedure who had CLTI.
For ease of description, we have divided the patients into three categories based on the level of aortic clamping. Out of 40 patients, 5 (12.5%) had thrombus extending till the ostium of one of the renal arteries but not causing viscera-renal stenosis, thus allowing inter-renal clamp placement. In the second category, the thrombus was reaching the bilateral renal artery Ostia leaving no space in between for inter-renal clamping. Thus, suprarenal clamping was done in these patients. This category had 28 patients (70%) with different patterns of thrombus, as shown in [Figure 1]. Two patients (5%) in this category had right renal artery occlusion and renal atrophy. In the last category, seven patients (17.5%) underwent supraceliac clamping due to a thrombus extending up to the SMA and causing its occlusion or due to lack of space between SMA and renal artery Ostia for safe clamping [Figure 1].
The average intraoperative renal ischemic time was 16.8 min. The comparison of renal ischemic time with postoperative serum creatinine is shown in [Figure 3]. Twelve patients had renal ischemic time >20 min, out of which four patients developed a transient rise in serum creatinine in the postoperative period, which normalized by the third postoperative day (POD) and did not require any renal replacement therapy. All these 12 patients had a very firm organized thrombus adherent with the aortic wall and required judicious separation to avoid lifting of renal artery ostium and dissection. Only one patient developed renal failure requiring hemodialysis, but he expired following cardiac arrest. No renal insufficiency was detected in other patients. The analysis of the effect of intraoperative renal ischemic time on renal function on PODs 1 and 3 showed Pearson's coefficient values of 0.465 (P < 0.0001) and 0.243 (P = 0.001), respectively. These findings establish a significant positive correlation between intraoperative aortic clamping time (i.e., renal ischemic time) and a rise in the serum creatinine values on PODs 1 and 3. Thus, intraoperative renal ischemic time can be used as a measure to predict postoperative renal function. All five patients who developed renal dysfunction were from the type II category of JRAIO [Figure 1], where suprarenal clamping was required and had firmly adherent organized thrombus.
Figure 3: Correlation plot depicting the effect of intraoperative aortic clamping time (renal ischemic time) on serum creatinine values at PODs 1 and 3. r: Pearson's correlation coefficient. PODs: Postoperative daysThis effect of intraoperative renal ischemic time on postoperative renal function was further established by comparing the mean serum creatinine values between the two groups (i.e., renal ischemic time <20 min vs. ≥20 min). Although there were no differences in the preoperative mean serum creatinine values between the two groups (P = 0.26), postoperative mean serum creatinine values on days, 1 and 3 showed significant differences between the two groups [P = 0.0001 and P = 0.0005, respectively, [Table 2] and [Figure 4].
Figure 4: Line diagram showing pre-OP and postoperative mean serum creatinine values in the two groups. OP: Operative, POD: Postoperative dayNo intraoperative deaths were recorded. Perioperative mortality was 2/40 (5%). One patient with a normal preoperative stress thallium scan developed an acute cardiac event 2 weeks after surgery and expired. The second patient succumbed to acute renal failure and subsequent cardiac arrest on POD 10. Perioperative morbidity was 22.5%, as described in [Table 3]. At a mean follow-up of 26.7 ± 12.4 months, the graft patency rate was 100%; no patient had graft occlusion during this period. All the patients had palpable pulses in their lower limbs, and none complained of rest pain. An average postoperative ABI value of 1.02 ± 0.1 was recorded.
DiscussionJRAIO represents a relatively rare variant of TASC type D aortic disease, which should be considered separately from distal aortic occlusion in terms of anatomic characteristics, an indication of treatment, and a therapeutic approach.[4] Of the various risk factors such as smoking, diabetes mellitus, and hypertension, chronic smoking is the most important as 97.5% of patients were heavy smokers in our study. The thrombus organizes over time and ascends to the level of renal arteries. This thrombus approaching the level of renal arteries and SMA may cause renal failure, intestinal infarction, and even paraplegia.[4] In our study, two patients (5%) had SMA involvement and presented with features of chronic mesenteric ischemia, and two patients (5%) had unilateral renal artery occlusion and atrophy of the ipsilateral kidney. However, none of the patients had deranged renal function tests or paraplegia.
Although some patients with JRAIO and concomitant severe risk factors may be managed by extra-anatomic bypasses, most vascular surgeons agree that a direct inline approach to the aorta is warranted and provides better long-term results.[8] The classical surgical procedure used for totally occluded infrarenal aorta was described by Liddicoat and associates.[9] This method involves digital pressure control of the suprarenal aorta while the clot is removed through an incision in the infrarenal aorta, and the final remnants are flushed by arterial blood pressure as digital control is temporarily released. After clot removal, the aorta is clamped below the renal arteries and the operation proceeds as a standard ABFB. This method is not effective in all cases. We prefer aortic thrombectomy under direct vision with proximal aortic clamping [Figure 2] with both renal arteries clamped. We encountered an organized adherent clot in majority of our patients (n = 12; 30%), and relying only on digital milking and systemic pressure flow to clear the clot in such cases was not completely effective, and it would be safer to clamp both renal arteries before clamping of aorta, otherwise with unclamped renal arteries theoretical risk of atheroembolization is always associated. Compared to digital control, aortic clamp control allows us to restore the lumen of the occluded juxta renal aortic segment directly under vision after transection of the aorta. Most patients (70%) in the present study had thrombus patterns that required suprarenal clamping (Type II), as shown in [Figure 1], and only 12.5% of patients had proximal thrombus extent allowing inter-renal clamping (Type I). On rare occasions, as shown in type III of [Figure 1], the SMA may be too close to the origin of renal arteries leaving no space between them to place the clamp, or an eccentric thrombus may reach up to the SMA, not allowing safe placement of suprarenal clamp. Therefore, in these cases, supra-celiac clamping of the aorta will be prudent. We had 7 (17.5%) such cases in which we used supra celiac clamping for safe control of the aorta. Thus, this study describes various patterns of proximal thrombus extension and corresponding safe aortic clamping sites to reduce the risk of renal atheroembolism. This classification further expands our current understanding of the JRAIO presentation and surgical management.
We focused on keeping the renal ischemic time as short as possible, as this is the safest and most effective method for renal protection in addition to a safe clamping approach guided by the pattern of thrombus in the juxta-renal aortic bed.[10] As a means of renal protection, diuresis with mannitol or renal hypothermia with cold fluid injection before aortic cross-clamping can be used, but its effect are still controversial.[11],[12],[13] We used mannitol 20 g (100 ml) intraoperatively in all the patients. In our study, the average renal ischemic time was 16.8 min, with 12 patients (30%) having a clamping time of more than 20 min because these patients had firmly adherent thrombus, which takes time for safe clearance. Of these 12 patients, four (10%) developed a transient rise in postoperative serum creatinine levels, and one (2.5%) required hemodialysis. This compares favorably with the previously reported incidence of renal failure, which ranges from 0% to 25%.[1],[2],[9] In the present study, the comparison of renal function outcomes in <20 min and ≥20 min renal ischemic time groups showed a significant difference (P = 0.0001 and P = 0.0005 on PODs 1 and 3, respectively). Thus, highlighting the importance of keeping supra-renal aortic clamp time as short as possible, to reduce the deleterious effect on renal function test. According to Sutzko et al., the overall incidence of myocardial infarction is 2.4% in major noncardiac open vascular surgeries and 1.8% for ABFB.[14] In our study, mortality is 5% which is comparable with a study done by Madiba and Robbs.[3]
No patient in this series developed postoperative graft infection or thrombosis, in contrast to available literature, which reports a 1%–6% infection rate.[3],[15],[16] The patency rate in our study was 100% at a mean follow-up of 26.7 ± 12.4 months. However, we believe that traditional definitions of treatment success like graft patency may not correlate well with limb preservation, as many patients with patent grafts may still require amputation because of gangrenous or infected tissues.
Endovascular treatment for the infrarenal aortic occlusive disease has been proposed as the first-line approach due to impressive results obtained in terms of periprocedural morbidity, secondary patency rates, and less invasivity.[17],[18],[19] However, when juxtarenal occlusion is present, endovascular management as first-line modality becomes controversial; however, with technological improvement, better results are reported.[5] In JRAIO, technical success of 100% has been reported with endovascular management, at a mean follow-up of 18 months (range 6–30 months). The primary and secondary patency was, respectively, 92.3% and 100%.[18] Surgery still provides a better long-term primary patency rate than endovascular treatment, even though endovascular re-intervention can achieve 80%–98% secondary patency rates.[20]
ConclusionThe aortic bypass procedure following aortorenal thromboendarterectomy for JRAIO is a challenging procedure. Classification based on the proximal extent of disease in relation to viscero-renal vessels will help in better decision-making about the site of aortic clamping to avoid complications related to renal atheroembolization.
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Conflicts of interest
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References
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