Does the type of renal artery anatomic variant determine the diameter of the main vessel supplying a kidney? A study based on CT data with a particular focus on the presence of multiple renal arteries

Wunderlich Syndrome: Spontaneous Cystic Rupture on Account of Acquired Kidney Atrophy

Wunderlich syndrome is an uncommon condition of spontaneous subcapsular and perirenal hemorrhage of atraumatic etiology in the kidney, with the potential to spread to the retroperitoneal region beyond the perirenal fascias. Its clinical manifestations usually include Lenk's triad, namely, acute flank pain, flank mass, and hemodynamic instability, which vary depending on the causative underlying renal pathology. Tumor bleeding of benign and malignant renal neoplasms is the most common cause of this syndrome, followed by vascular disorders and renal cystic diseases. Here, we report the case of a unilateral subcapsular renal hematoma on account of a left atrophic kidney with parapelvic cystic formations and variant hypoplastic vasculature which was successfully managed via radical nephrectomy after initial conservative treatment. Spontaneous cystic rupture contributed to the emergence of the syndrome, and its mechanisms are being addressed.

Target vessel displacement during fenestrated and branched endovascular aortic repair and its implications for the role of traditional computed tomography angiography roadmaps

Background

This retrospective study quantifies target vessel displacement during fenestrated and branched endovascular aneurysm repair due to the introduction of stiff guidewires and stent graft delivery systems. The effect that intraoperative vessel displacement has on the usability of computed tomography angiography (CTA) roadmaps is also addressed.

Methods

Patients that underwent fenestrated or branched EVAR were included in this retrospective study. Two imaging datasets were collected from each patient: (I) preoperative CTA and (II) intraoperative contrast-enhanced cone beam computed tomography (ceCBCT) acquired after the insertion of the stiff guidewire and stent graft delivery system. After image registration, the 3D coordinates of the ostium of the celiac artery, superior mesenteric artery, right renal artery and left renal artery were recorded in both the CTA and the ceCBCT dataset by two observers. The three-dimensional displacement of the ostia of the target vessels was calculated by subtracting the coordinates of CTA and ceCBCT from one another. Additionally, the tortuosity index and the maximum angulation of the aorta were calculated.

Results

In total 20 patients and 77 target vessels were included in this study. The ostium of the celiac, superior mesenteric, right renal and left renal artery underwent non-uniform three-dimensional displacement with mean absolute displacement of 8.2, 7.7, 8.2 and 6.2 mm, respectively. The average displacement of all different target vessels together was 7.8 mm. A moderate correlation between vessel displacement and the maximum angulation of the aortoiliac segment was found (Spearman's ρ=0.45, P<0.05).

Conclusions

The introduction of stiff endovascular devices during fenestrated or branched EVAR causes significant, non-uniform displacement of the ostium of the visceral and renal target vessels. Consequently, preoperative CTA roadmaps based on bone registration are suboptimal to guide target vessel catheterization during these procedures.

A systematic review of three-dimensional printed template-assisted physician-modified stent grafts for fenestrated endovascular aneurysm repair

OBJECTIVE

Fenestrated endovascular aneurysm repair has yet to gain widespread adoption owing to the technical complexity and increased risk of complications. Three-dimensional (3D) printed templates to guide fenestrated physician-modified stent grafts (PMSGs) are a novel technique that may have the potential to increase the accuracy of fenestration alignment, and to disrupt both the cost and timing of the current commercial fenestrated endograft supply chain. We have conducted a critical appraisal of the emerging literature to assess this.

METHODS

A systematic literature search was performed using PubMed and OVID Medline as guided by the PRISMA statement on April 30, 2020. We used "3D printing" and "physician modified" or "surgeon modified" and all related search terms. We identified 50 articles which met our search criteria. None articles were included as being of direct relevance to 3D-printed template-assisted PMSGs for fenestrated endovascular aneurysm repair. Abstracts were screened individually by each investigator to ensure relevance.

RESULTS

Nine relevant articles were identified for critical analysis. These included one technical report, five case reports or series, two prospective trials, and one letter to the editor.

CONCLUSIONS

These 3D-printed templates are a promising new avenue to assist with the placement of fenestrations in PMSGs, particularly in urgent or emergent cases where custom fenestrated endografts are unavailable, with larger scale studies warranted. Further work to validate the key stages of the template workflow are required, as well as further investigation into the most suitable manufacturing and distribution methods before the mainstream implementation of this novel technique.

Methylene blue usage for determining accessory artery ligation in donor kidneys

Objectives. We present a technique for determining whether to ligate or preserve accessory arteries in donor kidneys before implantation. Methods. Forty-three living-related donor kidneys in patients from January 2014 to February 2018 at our institution were included, all of which had dual arteries without the same stem. Among them, 19 cases of accessory arterial blood supply were evaluated using methylene blue (MB) perfusion, and accessory arteries supplying less than 10% of the total MB perfusion volume were ligated. The other 24 cases were assessed using a conventional method in which arteries with diameters less than 2 mm were ligated. The back-table surgical time, Doppler ultrasonography index, renal function and complications were compared between the 2 groups. Results. All patients underwent successful kidney transplantation. The back-table surgical time in the MB group was longer than that in the conventional group (42.70 ± 4.70 min vs 34.64 ± 5.30 min, P < .05). The serum creatinine level in the MB group was significantly lower than that in the conventional group 1 month after the operation (103.15 ± 19.26 μmol/L vs 119.17 ± 28.32 μmol/L, P < .05). No differences in the Doppler ultrasonography index or postoperative complications were noted. Conclusions. MB perfusion provides an easy and effective method to make decisions regarding arterial ligation and helps preserve renal function without increasing the number of complications after transplantation.

MVP (Micro Vascular Plug®) embolization of severe renal hemorrhages after nephrostomic tube placement

Background

We report our experience in managing iatrogenic renal bleedings after nephrostomic procedures by transarterial embolization using Micro Vascular Plug (MVP) (Medtronic, USA) as single or complementary embolization device with parenchimal sparing.

Materials and methods

Five patients have been treated in a single center with transarterial embolization because of renal hemorrhages occurring after positioning of nephrostomic drainages.

All patients presented with back pain, severe hematuria and/or bright red blood into the nephrostomic bag, with fall in hemoglobin value.

After contrast enhanced CT scan confirming arterial active bleeding, rescue embolization was performed using MVP.

The renal parenchimal loss was estimated on final postembolization DSA. Creatinine values were monitored before and after the procedure.

Results

Technical and clinical successes were obtained in all patients.

Two patients presented with extraluminal blush, one with multiple pseudoaneurysms, one with pseudoaneurysm with arterovenous fistula, one with extraluminal blush with arterovenous fistula.

MVP models were choosen oversized because of vasospasm that would underestimate the effective caliber of target vessel; MVP 3Q and MVP 7Q were adopted in one patient each, while MVP 5Q was released in three cases.

MVP was the sole embolizing agent in four patients; in one patient, MVP was employed after microcoils failed to obtain complete embolization.

The percentage of renal parenchimal lost was lower than 20%; no increase in Creatinine values was detected at dismission.

Conclusions

According to proposed data, MVP seems to be a safe, effective and fast embolizing device that interventionalists could consider when facing renal bleedings, even as sole agent.

Renal-aortic ratio as an objective measure of renal artery diameter a computed tomography angiography study

Background

Considering vital role of renal arteries in many surgical procedures, diameter of renal arteries seems to be an important measure of kidney perfusion. In this study, we analyzed a new parameter, renal-aortic ratio (R-Ar) as an objective measure of the renal artery diameter.

Method

The study included CT angiographic images from 254 patients (129 women and 125 men). R-Ar was calculated by dividing the diameter of the main renal artery for each kidney by the aortic diameter.

Results

R-Ar values for the whole study group ranged between 0.0863 and 0.5083; the ranges of R-Ar values for women and men patients were 0.1150–0.5083 and 0.0863–0.4449, respectively. In 412 cases (81.10%), the kidney was supplied by a single renal artery (RA variant) and in 96 (18.90%) by more than one artery (sRA variant). A significant difference was found in R-Ar values for RA and sRA variants (p = 0.0008). When the anatomical variant of renal perfusion was not considered on statistical analysis, a significant difference was found between the R-Ar values for women and men (p = 0.0259). No statistically significant difference was observed in R-Ar values for the right and left kidneys (p = 0.3123). Spearman’s coefficient of rank correlation between patient age and renal-aortic ratio values for the whole study group equaled − 0.36.

Conclusion

The analysis of the renal-aortic ratio values demonstrated that the diameter of renal arteries depended primarily on their number, and the relative diameter of renal arteries in women was larger than in men.

The level of origin of renal arteries in horseshoe kidney vs. in separated kidneys: CT-based study

Purpose

Horseshoe kidney is a rare congenital anomaly with potential clinical implications. The aim of this study was to determine the number of renal arteries and veins and the level at which the arteries branched off their parental vessels in individuals with horseshoe kidney (HSK) and in persons with separated kidneys (SK).

Materials and methods

The analysis included computed tomography angiography studies of 331 patients (83 HSK and 248 SK). The number of renal vessels and diameters of renal arteries were determined, along with the level at which they branched in relation to other ramifications (four groups of origin were proposed) and their entrance of the vessels to the kidney.

Results

Number of renal arteries in HSK group was 4.57 ± 1.39 per patient and 2.4 ± 0.43 in SK group (p < 0.0001). The distribution of branching level of renal arteries in HSK group was: I group ~ 57%, II group ~ 27%, III group ~ 15% and IV group < 1%, whereas in SK group the distribution was respectively: I group ~ 99%, II group < 1%, III and IV group − 0% (p = 0.0001). In HSK group, diameter of renal arteries branching above the IMA was 4.61 ± 1.58 mm, as compared with 3.96 ± 1.34 mm for the arteries branching below (p = 0.0004). Number of veins was 566 in SK group (87.70% of kidneys were supplied by single vein) and 323 in HSK group (9.64% kidneys were supplied by two veins) (p < 0.0001).

Conclusion

In HSK group, renal arteries significantly more often branch off their parental vessels below the origin of IMA and such vessels are usually smaller.

Rare combined variations of renal, suprarenal, phrenic and accessory hepatic arteries

Knowledge of the morphological variations within the abdominal cavity is significant for all medical practitioners planning surgery. This report presents the rare origin of a common trunk for the right inferior phrenic artery, and superior and inferior suprarenal artery from the right renal artery. An accessory hepatic artery was found, which served as a branch of the right inferior phrenic artery. The diameter of the common trunk was 3.95 mm, and the diameters of the inferior and superior suprarenal arteries were 1.84 and 1.36 mm, respectively. The diameter of the right inferior phrenic artery was 2.55 mm. Both the embryological background and the potential clinical significance of this morphological variation are discussed. Knowledge of this common trunk and the occurrence of the accessory right hepatic artery may be of significance in diagnostic and surgical procedures.